fs/btrfs/inode.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/bio.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/file.h>
  23 #include <linux/fs.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/highmem.h>
  26 #include <linux/time.h>
  27 #include <linux/init.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mpage.h>
  31 #include <linux/swap.h>
  32 #include <linux/writeback.h>
  33 #include <linux/compat.h>
  34 #include <linux/bit_spinlock.h>
  35 #include <linux/xattr.h>
  36 #include <linux/posix_acl.h>
  37 #include <linux/falloc.h>
  38 #include <linux/slab.h>
  39 #include <linux/ratelimit.h>
  40 #include <linux/mount.h>
  41 #include <linux/btrfs.h>
  42 #include <linux/blkdev.h>
  43 #include <linux/posix_acl_xattr.h>
  44 #include <linux/uio.h>
  45 #include "ctree.h"
  46 #include "disk-io.h"
  47 #include "transaction.h"
  48 #include "btrfs_inode.h"
  49 #include "print-tree.h"
  50 #include "ordered-data.h"
  51 #include "xattr.h"
  52 #include "tree-log.h"
  53 #include "volumes.h"
  54 #include "compression.h"
  55 #include "locking.h"
  56 #include "free-space-cache.h"
  57 #include "inode-map.h"
  58 #include "backref.h"
  59 #include "hash.h"
  60 #include "props.h"
  61 #include "qgroup.h"
  62 #include "dedupe.h"
  63
  64 struct btrfs_iget_args {
  65         struct btrfs_key *location;
  66         struct btrfs_root *root;
  67 };
  68
  69 struct btrfs_dio_data {
  70         u64 outstanding_extents;
  71         u64 reserve;
  72         u64 unsubmitted_oe_range_start;
  73         u64 unsubmitted_oe_range_end;
  74         int overwrite;
  75 };
  76
  77 static const struct inode_operations btrfs_dir_inode_operations;
  78 static const struct inode_operations btrfs_symlink_inode_operations;
  79 static const struct inode_operations btrfs_dir_ro_inode_operations;
  80 static const struct inode_operations btrfs_special_inode_operations;
  81 static const struct inode_operations btrfs_file_inode_operations;
  82 static const struct address_space_operations btrfs_aops;
  83 static const struct address_space_operations btrfs_symlink_aops;
  84 static const struct file_operations btrfs_dir_file_operations;
  85 static const struct extent_io_ops btrfs_extent_io_ops;
  86
  87 static struct kmem_cache *btrfs_inode_cachep;
  88 struct kmem_cache *btrfs_trans_handle_cachep;
  89 struct kmem_cache *btrfs_transaction_cachep;
  90 struct kmem_cache *btrfs_path_cachep;
  91 struct kmem_cache *btrfs_free_space_cachep;
  92
  93 #define S_SHIFT 12
  94 static const unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  95         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  96         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  97         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  98         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  99         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
 100         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
 101         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
 102 };
 103
 104 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
 105 static int btrfs_truncate(struct inode *inode);
 106 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
 107 static noinline int cow_file_range(struct inode *inode,
 108                                    struct page *locked_page,
 109                                    u64 start, u64 end, u64 delalloc_end,
 110                                    int *page_started, unsigned long *nr_written,
 111                                    int unlock, struct btrfs_dedupe_hash *hash);
 112 static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len,
 113                                        u64 orig_start, u64 block_start,
 114                                        u64 block_len, u64 orig_block_len,
 115                                        u64 ram_bytes, int compress_type,
 116                                        int type);
 117
 118 static int btrfs_dirty_inode(struct inode *inode);
 119
 120 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 121 void btrfs_test_inode_set_ops(struct inode *inode)
 122 {
 123         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
 124 }
 125 #endif
 126
 127 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 128                                      struct inode *inode,  struct inode *dir,
 129                                      const struct qstr *qstr)
 130 {
 131         int err;
 132
 133         err = btrfs_init_acl(trans, inode, dir);
 134         if (!err)
 135                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 136         return err;
 137 }
 138
 139 /*
 140  * this does all the hard work for inserting an inline extent into
 141  * the btree.  The caller should have done a btrfs_drop_extents so that
 142  * no overlapping inline items exist in the btree
 143  */
 144 static int insert_inline_extent(struct btrfs_trans_handle *trans,
 145                                 struct btrfs_path *path, int extent_inserted,
 146                                 struct btrfs_root *root, struct inode *inode,
 147                                 u64 start, size_t size, size_t compressed_size,
 148                                 int compress_type,
 149                                 struct page **compressed_pages)
 150 {
 151         struct extent_buffer *leaf;
 152         struct page *page = NULL;
 153         char *kaddr;
 154         unsigned long ptr;
 155         struct btrfs_file_extent_item *ei;
 156         int err = 0;
 157         int ret;
 158         size_t cur_size = size;
 159         unsigned long offset;
 160
 161         if (compressed_size && compressed_pages)
 162                 cur_size = compressed_size;
 163
 164         inode_add_bytes(inode, size);
 165
 166         if (!extent_inserted) {
 167                 struct btrfs_key key;
 168                 size_t datasize;
 169
 170                 key.objectid = btrfs_ino(BTRFS_I(inode));
 171                 key.offset = start;
 172                 key.type = BTRFS_EXTENT_DATA_KEY;
 173
 174                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 175                 path->leave_spinning = 1;
 176                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 177                                               datasize);
 178                 if (ret) {
 179                         err = ret;
 180                         goto fail;
 181                 }
 182         }
 183         leaf = path->nodes[0];
 184         ei = btrfs_item_ptr(leaf, path->slots[0],
 185                             struct btrfs_file_extent_item);
 186         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 187         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 188         btrfs_set_file_extent_encryption(leaf, ei, 0);
 189         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 190         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 191         ptr = btrfs_file_extent_inline_start(ei);
 192
 193         if (compress_type != BTRFS_COMPRESS_NONE) {
 194                 struct page *cpage;
 195                 int i = 0;
 196                 while (compressed_size > 0) {
 197                         cpage = compressed_pages[i];
 198                         cur_size = min_t(unsigned long, compressed_size,
 199                                        PAGE_SIZE);
 200
 201                         kaddr = kmap_atomic(cpage);
 202                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 203                         kunmap_atomic(kaddr);
 204
 205                         i++;
 206                         ptr += cur_size;
 207                         compressed_size -= cur_size;
 208                 }
 209                 btrfs_set_file_extent_compression(leaf, ei,
 210                                                   compress_type);
 211         } else {
 212                 page = find_get_page(inode->i_mapping,
 213                                      start >> PAGE_SHIFT);
 214                 btrfs_set_file_extent_compression(leaf, ei, 0);
 215                 kaddr = kmap_atomic(page);
 216                 offset = start & (PAGE_SIZE - 1);
 217                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 218                 kunmap_atomic(kaddr);
 219                 put_page(page);
 220         }
 221         btrfs_mark_buffer_dirty(leaf);
 222         btrfs_release_path(path);
 223
 224         /*
 225          * we're an inline extent, so nobody can
 226          * extend the file past i_size without locking
 227          * a page we already have locked.
 228          *
 229          * We must do any isize and inode updates
 230          * before we unlock the pages.  Otherwise we
 231          * could end up racing with unlink.
 232          */
 233         BTRFS_I(inode)->disk_i_size = inode->i_size;
 234         ret = btrfs_update_inode(trans, root, inode);
 235
 236         return ret;
 237 fail:
 238         return err;
 239 }
 240
 241
 242 /*
 243  * conditionally insert an inline extent into the file.  This
 244  * does the checks required to make sure the data is small enough
 245  * to fit as an inline extent.
 246  */
 247 static noinline int cow_file_range_inline(struct btrfs_root *root,
 248                                           struct inode *inode, u64 start,
 249                                           u64 end, size_t compressed_size,
 250                                           int compress_type,
 251                                           struct page **compressed_pages)
 252 {
 253         struct btrfs_fs_info *fs_info = root->fs_info;
 254         struct btrfs_trans_handle *trans;
 255         u64 isize = i_size_read(inode);
 256         u64 actual_end = min(end + 1, isize);
 257         u64 inline_len = actual_end - start;
 258         u64 aligned_end = ALIGN(end, fs_info->sectorsize);
 259         u64 data_len = inline_len;
 260         int ret;
 261         struct btrfs_path *path;
 262         int extent_inserted = 0;
 263         u32 extent_item_size;
 264
 265         if (compressed_size)
 266                 data_len = compressed_size;
 267
 268         if (start > 0 ||
 269             actual_end > fs_info->sectorsize ||
 270             data_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info) ||
 271             (!compressed_size &&
 272             (actual_end & (fs_info->sectorsize - 1)) == 0) ||
 273             end + 1 < isize ||
 274             data_len > fs_info->max_inline) {
 275                 return 1;
 276         }
 277
 278         path = btrfs_alloc_path();
 279         if (!path)
 280                 return -ENOMEM;
 281
 282         trans = btrfs_join_transaction(root);
 283         if (IS_ERR(trans)) {
 284                 btrfs_free_path(path);
 285                 return PTR_ERR(trans);
 286         }
 287         trans->block_rsv = &fs_info->delalloc_block_rsv;
 288
 289         if (compressed_size && compressed_pages)
 290                 extent_item_size = btrfs_file_extent_calc_inline_size(
 291                    compressed_size);
 292         else
 293                 extent_item_size = btrfs_file_extent_calc_inline_size(
 294                     inline_len);
 295
 296         ret = __btrfs_drop_extents(trans, root, inode, path,
 297                                    start, aligned_end, NULL,
 298                                    1, 1, extent_item_size, &extent_inserted);
 299         if (ret) {
 300                 btrfs_abort_transaction(trans, ret);
 301                 goto out;
 302         }
 303
 304         if (isize > actual_end)
 305                 inline_len = min_t(u64, isize, actual_end);
 306         ret = insert_inline_extent(trans, path, extent_inserted,
 307                                    root, inode, start,
 308                                    inline_len, compressed_size,
 309                                    compress_type, compressed_pages);
 310         if (ret && ret != -ENOSPC) {
 311                 btrfs_abort_transaction(trans, ret);
 312                 goto out;
 313         } else if (ret == -ENOSPC) {
 314                 ret = 1;
 315                 goto out;
 316         }
 317
 318         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 319         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 320         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 321 out:
 322         /*
 323          * Don't forget to free the reserved space, as for inlined extent
 324          * it won't count as data extent, free them directly here.
 325          * And at reserve time, it's always aligned to page size, so
 326          * just free one page here.
 327          */
 328         btrfs_qgroup_free_data(inode, 0, PAGE_SIZE);
 329         btrfs_free_path(path);
 330         btrfs_end_transaction(trans);
 331         return ret;
 332 }
 333
 334 struct async_extent {
 335         u64 start;
 336         u64 ram_size;
 337         u64 compressed_size;
 338         struct page **pages;
 339         unsigned long nr_pages;
 340         int compress_type;
 341         struct list_head list;
 342 };
 343
 344 struct async_cow {
 345         struct inode *inode;
 346         struct btrfs_root *root;
 347         struct page *locked_page;
 348         u64 start;
 349         u64 end;
 350         struct list_head extents;
 351         struct btrfs_work work;
 352 };
 353
 354 static noinline int add_async_extent(struct async_cow *cow,
 355                                      u64 start, u64 ram_size,
 356                                      u64 compressed_size,
 357                                      struct page **pages,
 358                                      unsigned long nr_pages,
 359                                      int compress_type)
 360 {
 361         struct async_extent *async_extent;
 362
 363         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 364         BUG_ON(!async_extent); /* -ENOMEM */
 365         async_extent->start = start;
 366         async_extent->ram_size = ram_size;
 367         async_extent->compressed_size = compressed_size;
 368         async_extent->pages = pages;
 369         async_extent->nr_pages = nr_pages;
 370         async_extent->compress_type = compress_type;
 371         list_add_tail(&async_extent->list, &cow->extents);
 372         return 0;
 373 }
 374
 375 static inline int inode_need_compress(struct inode *inode)
 376 {
 377         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 378
 379         /* force compress */
 380         if (btrfs_test_opt(fs_info, FORCE_COMPRESS))
 381                 return 1;
 382         /* bad compression ratios */
 383         if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 384                 return 0;
 385         if (btrfs_test_opt(fs_info, COMPRESS) ||
 386             BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS ||
 387             BTRFS_I(inode)->force_compress)
 388                 return 1;
 389         return 0;
 390 }
 391
 392 static inline void inode_should_defrag(struct inode *inode,
 393                 u64 start, u64 end, u64 num_bytes, u64 small_write)
 394 {
 395         /* If this is a small write inside eof, kick off a defrag */
 396         if (num_bytes < small_write &&
 397             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 398                 btrfs_add_inode_defrag(NULL, inode);
 399 }
 400
 401 /*
 402  * we create compressed extents in two phases.  The first
 403  * phase compresses a range of pages that have already been
 404  * locked (both pages and state bits are locked).
 405  *
 406  * This is done inside an ordered work queue, and the compression
 407  * is spread across many cpus.  The actual IO submission is step
 408  * two, and the ordered work queue takes care of making sure that
 409  * happens in the same order things were put onto the queue by
 410  * writepages and friends.
 411  *
 412  * If this code finds it can't get good compression, it puts an
 413  * entry onto the work queue to write the uncompressed bytes.  This
 414  * makes sure that both compressed inodes and uncompressed inodes
 415  * are written in the same order that the flusher thread sent them
 416  * down.
 417  */
 418 static noinline void compress_file_range(struct inode *inode,
 419                                         struct page *locked_page,
 420                                         u64 start, u64 end,
 421                                         struct async_cow *async_cow,
 422                                         int *num_added)
 423 {
 424         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 425         struct btrfs_root *root = BTRFS_I(inode)->root;
 426         u64 num_bytes;
 427         u64 blocksize = fs_info->sectorsize;
 428         u64 actual_end;
 429         u64 isize = i_size_read(inode);
 430         int ret = 0;
 431         struct page **pages = NULL;
 432         unsigned long nr_pages;
 433         unsigned long nr_pages_ret = 0;
 434         unsigned long total_compressed = 0;
 435         unsigned long total_in = 0;
 436         unsigned long max_compressed = SZ_128K;
 437         unsigned long max_uncompressed = SZ_128K;
 438         int i;
 439         int will_compress;
 440         int compress_type = fs_info->compress_type;
 441         int redirty = 0;
 442
 443         inode_should_defrag(inode, start, end, end - start + 1, SZ_16K);
 444
 445         actual_end = min_t(u64, isize, end + 1);
 446 again:
 447         will_compress = 0;
 448         nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
 449         nr_pages = min_t(unsigned long, nr_pages, SZ_128K / PAGE_SIZE);
 450
 451         /*
 452          * we don't want to send crud past the end of i_size through
 453          * compression, that's just a waste of CPU time.  So, if the
 454          * end of the file is before the start of our current
 455          * requested range of bytes, we bail out to the uncompressed
 456          * cleanup code that can deal with all of this.
 457          *
 458          * It isn't really the fastest way to fix things, but this is a
 459          * very uncommon corner.
 460          */
 461         if (actual_end <= start)
 462                 goto cleanup_and_bail_uncompressed;
 463
 464         total_compressed = actual_end - start;
 465
 466         /*
 467          * skip compression for a small file range(<=blocksize) that
 468          * isn't an inline extent, since it doesn't save disk space at all.
 469          */
 470         if (total_compressed <= blocksize &&
 471            (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 472                 goto cleanup_and_bail_uncompressed;
 473
 474         /* we want to make sure that amount of ram required to uncompress
 475          * an extent is reasonable, so we limit the total size in ram
 476          * of a compressed extent to 128k.  This is a crucial number
 477          * because it also controls how easily we can spread reads across
 478          * cpus for decompression.
 479          *
 480          * We also want to make sure the amount of IO required to do
 481          * a random read is reasonably small, so we limit the size of
 482          * a compressed extent to 128k.
 483          */
 484         total_compressed = min(total_compressed, max_uncompressed);
 485         num_bytes = ALIGN(end - start + 1, blocksize);
 486         num_bytes = max(blocksize,  num_bytes);
 487         total_in = 0;
 488         ret = 0;
 489
 490         /*
 491          * we do compression for mount -o compress and when the
 492          * inode has not been flagged as nocompress.  This flag can
 493          * change at any time if we discover bad compression ratios.
 494          */
 495         if (inode_need_compress(inode)) {
 496                 WARN_ON(pages);
 497                 pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
 498                 if (!pages) {
 499                         /* just bail out to the uncompressed code */
 500                         goto cont;
 501                 }
 502
 503                 if (BTRFS_I(inode)->force_compress)
 504                         compress_type = BTRFS_I(inode)->force_compress;
 505
 506                 /*
 507                  * we need to call clear_page_dirty_for_io on each
 508                  * page in the range.  Otherwise applications with the file
 509                  * mmap'd can wander in and change the page contents while
 510                  * we are compressing them.
 511                  *
 512                  * If the compression fails for any reason, we set the pages
 513                  * dirty again later on.
 514                  */
 515                 extent_range_clear_dirty_for_io(inode, start, end);
 516                 redirty = 1;
 517                 ret = btrfs_compress_pages(compress_type,
 518                                            inode->i_mapping, start,
 519                                            total_compressed, pages,
 520                                            nr_pages, &nr_pages_ret,
 521                                            &total_in,
 522                                            &total_compressed,
 523                                            max_compressed);
 524
 525                 if (!ret) {
 526                         unsigned long offset = total_compressed &
 527                                 (PAGE_SIZE - 1);
 528                         struct page *page = pages[nr_pages_ret - 1];
 529                         char *kaddr;
 530
 531                         /* zero the tail end of the last page, we might be
 532                          * sending it down to disk
 533                          */
 534                         if (offset) {
 535                                 kaddr = kmap_atomic(page);
 536                                 memset(kaddr + offset, 0,
 537                                        PAGE_SIZE - offset);
 538                                 kunmap_atomic(kaddr);
 539                         }
 540                         will_compress = 1;
 541                 }
 542         }
 543 cont:
 544         if (start == 0) {
 545                 /* lets try to make an inline extent */
 546                 if (ret || total_in < (actual_end - start)) {
 547                         /* we didn't compress the entire range, try
 548                          * to make an uncompressed inline extent.
 549                          */
 550                         ret = cow_file_range_inline(root, inode, start, end,
 551                                             0, BTRFS_COMPRESS_NONE, NULL);
 552                 } else {
 553                         /* try making a compressed inline extent */
 554                         ret = cow_file_range_inline(root, inode, start, end,
 555                                                     total_compressed,
 556                                                     compress_type, pages);
 557                 }
 558                 if (ret <= 0) {
 559                         unsigned long clear_flags = EXTENT_DELALLOC |
 560                                 EXTENT_DEFRAG;
 561                         unsigned long page_error_op;
 562
 563                         clear_flags |= (ret < 0) ? EXTENT_DO_ACCOUNTING : 0;
 564                         page_error_op = ret < 0 ? PAGE_SET_ERROR : 0;
 565
 566                         /*
 567                          * inline extent creation worked or returned error,
 568                          * we don't need to create any more async work items.
 569                          * Unlock and free up our temp pages.
 570                          */
 571                         extent_clear_unlock_delalloc(inode, start, end, end,
 572                                                      NULL, clear_flags,
 573                                                      PAGE_UNLOCK |
 574                                                      PAGE_CLEAR_DIRTY |
 575                                                      PAGE_SET_WRITEBACK |
 576                                                      page_error_op |
 577                                                      PAGE_END_WRITEBACK);
 578                         btrfs_free_reserved_data_space_noquota(inode, start,
 579                                                 end - start + 1);
 580                         goto free_pages_out;
 581                 }
 582         }
 583
 584         if (will_compress) {
 585                 /*
 586                  * we aren't doing an inline extent round the compressed size
 587                  * up to a block size boundary so the allocator does sane
 588                  * things
 589                  */
 590                 total_compressed = ALIGN(total_compressed, blocksize);
 591
 592                 /*
 593                  * one last check to make sure the compression is really a
 594                  * win, compare the page count read with the blocks on disk
 595                  */
 596                 total_in = ALIGN(total_in, PAGE_SIZE);
 597                 if (total_compressed >= total_in) {
 598                         will_compress = 0;
 599                 } else {
 600                         num_bytes = total_in;
 601                         *num_added += 1;
 602
 603                         /*
 604                          * The async work queues will take care of doing actual
 605                          * allocation on disk for these compressed pages, and
 606                          * will submit them to the elevator.
 607                          */
 608                         add_async_extent(async_cow, start, num_bytes,
 609                                         total_compressed, pages, nr_pages_ret,
 610                                         compress_type);
 611
 612                         if (start + num_bytes < end) {
 613                                 start += num_bytes;
 614                                 pages = NULL;
 615                                 cond_resched();
 616                                 goto again;
 617                         }
 618                         return;
 619                 }
 620         }
 621         if (pages) {
 622                 /*
 623                  * the compression code ran but failed to make things smaller,
 624                  * free any pages it allocated and our page pointer array
 625                  */
 626                 for (i = 0; i < nr_pages_ret; i++) {
 627                         WARN_ON(pages[i]->mapping);
 628                         put_page(pages[i]);
 629                 }
 630                 kfree(pages);
 631                 pages = NULL;
 632                 total_compressed = 0;
 633                 nr_pages_ret = 0;
 634
 635                 /* flag the file so we don't compress in the future */
 636                 if (!btrfs_test_opt(fs_info, FORCE_COMPRESS) &&
 637                     !(BTRFS_I(inode)->force_compress)) {
 638                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 639                 }
 640         }
 641 cleanup_and_bail_uncompressed:
 642         /*
 643          * No compression, but we still need to write the pages in the file
 644          * we've been given so far.  redirty the locked page if it corresponds
 645          * to our extent and set things up for the async work queue to run
 646          * cow_file_range to do the normal delalloc dance.
 647          */
 648         if (page_offset(locked_page) >= start &&
 649             page_offset(locked_page) <= end)
 650                 __set_page_dirty_nobuffers(locked_page);
 651                 /* unlocked later on in the async handlers */
 652
 653         if (redirty)
 654                 extent_range_redirty_for_io(inode, start, end);
 655         add_async_extent(async_cow, start, end - start + 1, 0, NULL, 0,
 656                          BTRFS_COMPRESS_NONE);
 657         *num_added += 1;
 658
 659         return;
 660
 661 free_pages_out:
 662         for (i = 0; i < nr_pages_ret; i++) {
 663                 WARN_ON(pages[i]->mapping);
 664                 put_page(pages[i]);
 665         }
 666         kfree(pages);
 667 }
 668
 669 static void free_async_extent_pages(struct async_extent *async_extent)
 670 {
 671         int i;
 672
 673         if (!async_extent->pages)
 674                 return;
 675
 676         for (i = 0; i < async_extent->nr_pages; i++) {
 677                 WARN_ON(async_extent->pages[i]->mapping);
 678                 put_page(async_extent->pages[i]);
 679         }
 680         kfree(async_extent->pages);
 681         async_extent->nr_pages = 0;
 682         async_extent->pages = NULL;
 683 }
 684
 685 /*
 686  * phase two of compressed writeback.  This is the ordered portion
 687  * of the code, which only gets called in the order the work was
 688  * queued.  We walk all the async extents created by compress_file_range
 689  * and send them down to the disk.
 690  */
 691 static noinline void submit_compressed_extents(struct inode *inode,
 692                                               struct async_cow *async_cow)
 693 {
 694         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 695         struct async_extent *async_extent;
 696         u64 alloc_hint = 0;
 697         struct btrfs_key ins;
 698         struct extent_map *em;
 699         struct btrfs_root *root = BTRFS_I(inode)->root;
 700         struct extent_io_tree *io_tree;
 701         int ret = 0;
 702
 703 again:
 704         while (!list_empty(&async_cow->extents)) {
 705                 async_extent = list_entry(async_cow->extents.next,
 706                                           struct async_extent, list);
 707                 list_del(&async_extent->list);
 708
 709                 io_tree = &BTRFS_I(inode)->io_tree;
 710
 711 retry:
 712                 /* did the compression code fall back to uncompressed IO? */
 713                 if (!async_extent->pages) {
 714                         int page_started = 0;
 715                         unsigned long nr_written = 0;
 716
 717                         lock_extent(io_tree, async_extent->start,
 718                                          async_extent->start +
 719                                          async_extent->ram_size - 1);
 720
 721                         /* allocate blocks */
 722                         ret = cow_file_range(inode, async_cow->locked_page,
 723                                              async_extent->start,
 724                                              async_extent->start +
 725                                              async_extent->ram_size - 1,
 726                                              async_extent->start +
 727                                              async_extent->ram_size - 1,
 728                                              &page_started, &nr_written, 0,
 729                                              NULL);
 730
 731                         /* JDM XXX */
 732
 733                         /*
 734                          * if page_started, cow_file_range inserted an
 735                          * inline extent and took care of all the unlocking
 736                          * and IO for us.  Otherwise, we need to submit
 737                          * all those pages down to the drive.
 738                          */
 739                         if (!page_started && !ret)
 740                                 extent_write_locked_range(io_tree,
 741                                                   inode, async_extent->start,
 742                                                   async_extent->start +
 743                                                   async_extent->ram_size - 1,
 744                                                   btrfs_get_extent,
 745                                                   WB_SYNC_ALL);
 746                         else if (ret)
 747                                 unlock_page(async_cow->locked_page);
 748                         kfree(async_extent);
 749                         cond_resched();
 750                         continue;
 751                 }
 752
 753                 lock_extent(io_tree, async_extent->start,
 754                             async_extent->start + async_extent->ram_size - 1);
 755
 756                 ret = btrfs_reserve_extent(root, async_extent->ram_size,
 757                                            async_extent->compressed_size,
 758                                            async_extent->compressed_size,
 759                                            0, alloc_hint, &ins, 1, 1);
 760                 if (ret) {
 761                         free_async_extent_pages(async_extent);
 762
 763                         if (ret == -ENOSPC) {
 764                                 unlock_extent(io_tree, async_extent->start,
 765                                               async_extent->start +
 766                                               async_extent->ram_size - 1);
 767
 768                                 /*
 769                                  * we need to redirty the pages if we decide to
 770                                  * fallback to uncompressed IO, otherwise we
 771                                  * will not submit these pages down to lower
 772                                  * layers.
 773                                  */
 774                                 extent_range_redirty_for_io(inode,
 775                                                 async_extent->start,
 776                                                 async_extent->start +
 777                                                 async_extent->ram_size - 1);
 778
 779                                 goto retry;
 780                         }
 781                         goto out_free;
 782                 }
 783                 /*
 784                  * here we're doing allocation and writeback of the
 785                  * compressed pages
 786                  */
 787                 em = create_io_em(inode, async_extent->start,
 788                                   async_extent->ram_size, /* len */
 789                                   async_extent->start, /* orig_start */
 790                                   ins.objectid, /* block_start */
 791                                   ins.offset, /* block_len */
 792                                   ins.offset, /* orig_block_len */
 793                                   async_extent->ram_size, /* ram_bytes */
 794                                   async_extent->compress_type,
 795                                   BTRFS_ORDERED_COMPRESSED);
 796                 if (IS_ERR(em))
 797                         /* ret value is not necessary due to void function */
 798                         goto out_free_reserve;
 799                 free_extent_map(em);
 800
 801                 ret = btrfs_add_ordered_extent_compress(inode,
 802                                                 async_extent->start,
 803                                                 ins.objectid,
 804                                                 async_extent->ram_size,
 805                                                 ins.offset,
 806                                                 BTRFS_ORDERED_COMPRESSED,
 807                                                 async_extent->compress_type);
 808                 if (ret) {
 809                         btrfs_drop_extent_cache(inode, async_extent->start,
 810                                                 async_extent->start +
 811                                                 async_extent->ram_size - 1, 0);
 812                         goto out_free_reserve;
 813                 }
 814                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
 815
 816                 /*
 817                  * clear dirty, set writeback and unlock the pages.
 818                  */
 819                 extent_clear_unlock_delalloc(inode, async_extent->start,
 820                                 async_extent->start +
 821                                 async_extent->ram_size - 1,
 822                                 async_extent->start +
 823                                 async_extent->ram_size - 1,
 824                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 825                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 826                                 PAGE_SET_WRITEBACK);
 827                 ret = btrfs_submit_compressed_write(inode,
 828                                     async_extent->start,
 829                                     async_extent->ram_size,
 830                                     ins.objectid,
 831                                     ins.offset, async_extent->pages,
 832                                     async_extent->nr_pages);
 833                 if (ret) {
 834                         struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 835                         struct page *p = async_extent->pages[0];
 836                         const u64 start = async_extent->start;
 837                         const u64 end = start + async_extent->ram_size - 1;
 838
 839                         p->mapping = inode->i_mapping;
 840                         tree->ops->writepage_end_io_hook(p, start, end,
 841                                                          NULL, 0);
 842                         p->mapping = NULL;
 843                         extent_clear_unlock_delalloc(inode, start, end, end,
 844                                                      NULL, 0,
 845                                                      PAGE_END_WRITEBACK |
 846                                                      PAGE_SET_ERROR);
 847                         free_async_extent_pages(async_extent);
 848                 }
 849                 alloc_hint = ins.objectid + ins.offset;
 850                 kfree(async_extent);
 851                 cond_resched();
 852         }
 853         return;
 854 out_free_reserve:
 855         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
 856         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1);
 857 out_free:
 858         extent_clear_unlock_delalloc(inode, async_extent->start,
 859                                      async_extent->start +
 860                                      async_extent->ram_size - 1,
 861                                      async_extent->start +
 862                                      async_extent->ram_size - 1,
 863                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 864                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 865                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 866                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK |
 867                                      PAGE_SET_ERROR);
 868         free_async_extent_pages(async_extent);
 869         kfree(async_extent);
 870         goto again;
 871 }
 872
 873 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 874                                       u64 num_bytes)
 875 {
 876         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 877         struct extent_map *em;
 878         u64 alloc_hint = 0;
 879
 880         read_lock(&em_tree->lock);
 881         em = search_extent_mapping(em_tree, start, num_bytes);
 882         if (em) {
 883                 /*
 884                  * if block start isn't an actual block number then find the
 885                  * first block in this inode and use that as a hint.  If that
 886                  * block is also bogus then just don't worry about it.
 887                  */
 888                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 889                         free_extent_map(em);
 890                         em = search_extent_mapping(em_tree, 0, 0);
 891                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 892                                 alloc_hint = em->block_start;
 893                         if (em)
 894                                 free_extent_map(em);
 895                 } else {
 896                         alloc_hint = em->block_start;
 897                         free_extent_map(em);
 898                 }
 899         }
 900         read_unlock(&em_tree->lock);
 901
 902         return alloc_hint;
 903 }
 904
 905 /*
 906  * when extent_io.c finds a delayed allocation range in the file,
 907  * the call backs end up in this code.  The basic idea is to
 908  * allocate extents on disk for the range, and create ordered data structs
 909  * in ram to track those extents.
 910  *
 911  * locked_page is the page that writepage had locked already.  We use
 912  * it to make sure we don't do extra locks or unlocks.
 913  *
 914  * *page_started is set to one if we unlock locked_page and do everything
 915  * required to start IO on it.  It may be clean and already done with
 916  * IO when we return.
 917  */
 918 static noinline int cow_file_range(struct inode *inode,
 919                                    struct page *locked_page,
 920                                    u64 start, u64 end, u64 delalloc_end,
 921                                    int *page_started, unsigned long *nr_written,
 922                                    int unlock, struct btrfs_dedupe_hash *hash)
 923 {
 924         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 925         struct btrfs_root *root = BTRFS_I(inode)->root;
 926         u64 alloc_hint = 0;
 927         u64 num_bytes;
 928         unsigned long ram_size;
 929         u64 disk_num_bytes;
 930         u64 cur_alloc_size;
 931         u64 blocksize = fs_info->sectorsize;
 932         struct btrfs_key ins;
 933         struct extent_map *em;
 934         int ret = 0;
 935
 936         if (btrfs_is_free_space_inode(inode)) {
 937                 WARN_ON_ONCE(1);
 938                 ret = -EINVAL;
 939                 goto out_unlock;
 940         }
 941
 942         num_bytes = ALIGN(end - start + 1, blocksize);
 943         num_bytes = max(blocksize,  num_bytes);
 944         disk_num_bytes = num_bytes;
 945
 946         inode_should_defrag(inode, start, end, num_bytes, SZ_64K);
 947
 948         if (start == 0) {
 949                 /* lets try to make an inline extent */
 950                 ret = cow_file_range_inline(root, inode, start, end, 0,
 951                                         BTRFS_COMPRESS_NONE, NULL);
 952                 if (ret == 0) {
 953                         extent_clear_unlock_delalloc(inode, start, end,
 954                                      delalloc_end, NULL,
 955                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 956                                      EXTENT_DEFRAG, PAGE_UNLOCK |
 957                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 958                                      PAGE_END_WRITEBACK);
 959                         btrfs_free_reserved_data_space_noquota(inode, start,
 960                                                 end - start + 1);
 961                         *nr_written = *nr_written +
 962                              (end - start + PAGE_SIZE) / PAGE_SIZE;
 963                         *page_started = 1;
 964                         goto out;
 965                 } else if (ret < 0) {
 966                         goto out_unlock;
 967                 }
 968         }
 969
 970         BUG_ON(disk_num_bytes >
 971                btrfs_super_total_bytes(fs_info->super_copy));
 972
 973         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 974         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 975
 976         while (disk_num_bytes > 0) {
 977                 unsigned long op;
 978
 979                 cur_alloc_size = disk_num_bytes;
 980                 ret = btrfs_reserve_extent(root, cur_alloc_size, cur_alloc_size,
 981                                            fs_info->sectorsize, 0, alloc_hint,
 982                                            &ins, 1, 1);
 983                 if (ret < 0)
 984                         goto out_unlock;
 985
 986                 ram_size = ins.offset;
 987                 em = create_io_em(inode, start, ins.offset, /* len */
 988                                   start, /* orig_start */
 989                                   ins.objectid, /* block_start */
 990                                   ins.offset, /* block_len */
 991                                   ins.offset, /* orig_block_len */
 992                                   ram_size, /* ram_bytes */
 993                                   BTRFS_COMPRESS_NONE, /* compress_type */
 994                                   BTRFS_ORDERED_REGULAR /* type */);
 995                 if (IS_ERR(em))
 996                         goto out_reserve;
 997                 free_extent_map(em);
 998
 999                 cur_alloc_size = ins.offset;
1000                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
1001                                                ram_size, cur_alloc_size, 0);
1002                 if (ret)
1003                         goto out_drop_extent_cache;
1004
1005                 if (root->root_key.objectid ==
1006                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1007                         ret = btrfs_reloc_clone_csums(inode, start,
1008                                                       cur_alloc_size);
1009                         if (ret)
1010                                 goto out_drop_extent_cache;
1011                 }
1012
1013                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
1014
1015                 if (disk_num_bytes < cur_alloc_size)
1016                         break;
1017
1018                 /* we're not doing compressed IO, don't unlock the first
1019                  * page (which the caller expects to stay locked), don't
1020                  * clear any dirty bits and don't set any writeback bits
1021                  *
1022                  * Do set the Private2 bit so we know this page was properly
1023                  * setup for writepage
1024                  */
1025                 op = unlock ? PAGE_UNLOCK : 0;
1026                 op |= PAGE_SET_PRIVATE2;
1027
1028                 extent_clear_unlock_delalloc(inode, start,
1029                                              start + ram_size - 1,
1030                                              delalloc_end, locked_page,
1031                                              EXTENT_LOCKED | EXTENT_DELALLOC,
1032                                              op);
1033                 disk_num_bytes -= cur_alloc_size;
1034                 num_bytes -= cur_alloc_size;
1035                 alloc_hint = ins.objectid + ins.offset;
1036                 start += cur_alloc_size;
1037         }
1038 out:
1039         return ret;
1040
1041 out_drop_extent_cache:
1042         btrfs_drop_extent_cache(inode, start, start + ram_size - 1, 0);
1043 out_reserve:
1044         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
1045         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1);
1046 out_unlock:
1047         extent_clear_unlock_delalloc(inode, start, end, delalloc_end,
1048                                      locked_page,
1049                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
1050                                      EXTENT_DELALLOC | EXTENT_DEFRAG,
1051                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
1052                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
1053         goto out;
1054 }
1055
1056 /*
1057  * work queue call back to started compression on a file and pages
1058  */
1059 static noinline void async_cow_start(struct btrfs_work *work)
1060 {
1061         struct async_cow *async_cow;
1062         int num_added = 0;
1063         async_cow = container_of(work, struct async_cow, work);
1064
1065         compress_file_range(async_cow->inode, async_cow->locked_page,
1066                             async_cow->start, async_cow->end, async_cow,
1067                             &num_added);
1068         if (num_added == 0) {
1069                 btrfs_add_delayed_iput(async_cow->inode);
1070                 async_cow->inode = NULL;
1071         }
1072 }
1073
1074 /*
1075  * work queue call back to submit previously compressed pages
1076  */
1077 static noinline void async_cow_submit(struct btrfs_work *work)
1078 {
1079         struct btrfs_fs_info *fs_info;
1080         struct async_cow *async_cow;
1081         struct btrfs_root *root;
1082         unsigned long nr_pages;
1083
1084         async_cow = container_of(work, struct async_cow, work);
1085
1086         root = async_cow->root;
1087         fs_info = root->fs_info;
1088         nr_pages = (async_cow->end - async_cow->start + PAGE_SIZE) >>
1089                 PAGE_SHIFT;
1090
1091         /*
1092          * atomic_sub_return implies a barrier for waitqueue_active
1093          */
1094         if (atomic_sub_return(nr_pages, &fs_info->async_delalloc_pages) <
1095             5 * SZ_1M &&
1096             waitqueue_active(&fs_info->async_submit_wait))
1097                 wake_up(&fs_info->async_submit_wait);
1098
1099         if (async_cow->inode)
1100                 submit_compressed_extents(async_cow->inode, async_cow);
1101 }
1102
1103 static noinline void async_cow_free(struct btrfs_work *work)
1104 {
1105         struct async_cow *async_cow;
1106         async_cow = container_of(work, struct async_cow, work);
1107         if (async_cow->inode)
1108                 btrfs_add_delayed_iput(async_cow->inode);
1109         kfree(async_cow);
1110 }
1111
1112 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1113                                 u64 start, u64 end, int *page_started,
1114                                 unsigned long *nr_written)
1115 {
1116         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1117         struct async_cow *async_cow;
1118         struct btrfs_root *root = BTRFS_I(inode)->root;
1119         unsigned long nr_pages;
1120         u64 cur_end;
1121
1122         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1123                          1, 0, NULL, GFP_NOFS);
1124         while (start < end) {
1125                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1126                 BUG_ON(!async_cow); /* -ENOMEM */
1127                 async_cow->inode = igrab(inode);
1128                 async_cow->root = root;
1129                 async_cow->locked_page = locked_page;
1130                 async_cow->start = start;
1131
1132                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS &&
1133                     !btrfs_test_opt(fs_info, FORCE_COMPRESS))
1134                         cur_end = end;
1135                 else
1136                         cur_end = min(end, start + SZ_512K - 1);
1137
1138                 async_cow->end = cur_end;
1139                 INIT_LIST_HEAD(&async_cow->extents);
1140
1141                 btrfs_init_work(&async_cow->work,
1142                                 btrfs_delalloc_helper,
1143                                 async_cow_start, async_cow_submit,
1144                                 async_cow_free);
1145
1146                 nr_pages = (cur_end - start + PAGE_SIZE) >>
1147                         PAGE_SHIFT;
1148                 atomic_add(nr_pages, &fs_info->async_delalloc_pages);
1149
1150                 btrfs_queue_work(fs_info->delalloc_workers, &async_cow->work);
1151
1152                 while (atomic_read(&fs_info->async_submit_draining) &&
1153                        atomic_read(&fs_info->async_delalloc_pages)) {
1154                         wait_event(fs_info->async_submit_wait,
1155                                    (atomic_read(&fs_info->async_delalloc_pages) ==
1156                                     0));
1157                 }
1158
1159                 *nr_written += nr_pages;
1160                 start = cur_end + 1;
1161         }
1162         *page_started = 1;
1163         return 0;
1164 }
1165
1166 static noinline int csum_exist_in_range(struct btrfs_fs_info *fs_info,
1167                                         u64 bytenr, u64 num_bytes)
1168 {
1169         int ret;
1170         struct btrfs_ordered_sum *sums;
1171         LIST_HEAD(list);
1172
1173         ret = btrfs_lookup_csums_range(fs_info->csum_root, bytenr,
1174                                        bytenr + num_bytes - 1, &list, 0);
1175         if (ret == 0 && list_empty(&list))
1176                 return 0;
1177
1178         while (!list_empty(&list)) {
1179                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1180                 list_del(&sums->list);
1181                 kfree(sums);
1182         }
1183         return 1;
1184 }
1185
1186 /*
1187  * when nowcow writeback call back.  This checks for snapshots or COW copies
1188  * of the extents that exist in the file, and COWs the file as required.
1189  *
1190  * If no cow copies or snapshots exist, we write directly to the existing
1191  * blocks on disk
1192  */
1193 static noinline int run_delalloc_nocow(struct inode *inode,
1194                                        struct page *locked_page,
1195                               u64 start, u64 end, int *page_started, int force,
1196                               unsigned long *nr_written)
1197 {
1198         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1199         struct btrfs_root *root = BTRFS_I(inode)->root;
1200         struct extent_buffer *leaf;
1201         struct btrfs_path *path;
1202         struct btrfs_file_extent_item *fi;
1203         struct btrfs_key found_key;
1204         struct extent_map *em;
1205         u64 cow_start;
1206         u64 cur_offset;
1207         u64 extent_end;
1208         u64 extent_offset;
1209         u64 disk_bytenr;
1210         u64 num_bytes;
1211         u64 disk_num_bytes;
1212         u64 ram_bytes;
1213         int extent_type;
1214         int ret, err;
1215         int type;
1216         int nocow;
1217         int check_prev = 1;
1218         bool nolock;
1219         u64 ino = btrfs_ino(BTRFS_I(inode));
1220
1221         path = btrfs_alloc_path();
1222         if (!path) {
1223                 extent_clear_unlock_delalloc(inode, start, end, end,
1224                                              locked_page,
1225                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1226                                              EXTENT_DO_ACCOUNTING |
1227                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1228                                              PAGE_CLEAR_DIRTY |
1229                                              PAGE_SET_WRITEBACK |
1230                                              PAGE_END_WRITEBACK);
1231                 return -ENOMEM;
1232         }
1233
1234         nolock = btrfs_is_free_space_inode(inode);
1235
1236         cow_start = (u64)-1;
1237         cur_offset = start;
1238         while (1) {
1239                 ret = btrfs_lookup_file_extent(NULL, root, path, ino,
1240                                                cur_offset, 0);
1241                 if (ret < 0)
1242                         goto error;
1243                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1244                         leaf = path->nodes[0];
1245                         btrfs_item_key_to_cpu(leaf, &found_key,
1246                                               path->slots[0] - 1);
1247                         if (found_key.objectid == ino &&
1248                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1249                                 path->slots[0]--;
1250                 }
1251                 check_prev = 0;
1252 next_slot:
1253                 leaf = path->nodes[0];
1254                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1255                         ret = btrfs_next_leaf(root, path);
1256                         if (ret < 0)
1257                                 goto error;
1258                         if (ret > 0)
1259                                 break;
1260                         leaf = path->nodes[0];
1261                 }
1262
1263                 nocow = 0;
1264                 disk_bytenr = 0;
1265                 num_bytes = 0;
1266                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1267
1268                 if (found_key.objectid > ino)
1269                         break;
1270                 if (WARN_ON_ONCE(found_key.objectid < ino) ||
1271                     found_key.type < BTRFS_EXTENT_DATA_KEY) {
1272                         path->slots[0]++;
1273                         goto next_slot;
1274                 }
1275                 if (found_key.type > BTRFS_EXTENT_DATA_KEY ||
1276                     found_key.offset > end)
1277                         break;
1278
1279                 if (found_key.offset > cur_offset) {
1280                         extent_end = found_key.offset;
1281                         extent_type = 0;
1282                         goto out_check;
1283                 }
1284
1285                 fi = btrfs_item_ptr(leaf, path->slots[0],
1286                                     struct btrfs_file_extent_item);
1287                 extent_type = btrfs_file_extent_type(leaf, fi);
1288
1289                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1290                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1291                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1292                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1293                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1294                         extent_end = found_key.offset +
1295                                 btrfs_file_extent_num_bytes(leaf, fi);
1296                         disk_num_bytes =
1297                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1298                         if (extent_end <= start) {
1299                                 path->slots[0]++;
1300                                 goto next_slot;
1301                         }
1302                         if (disk_bytenr == 0)
1303                                 goto out_check;
1304                         if (btrfs_file_extent_compression(leaf, fi) ||
1305                             btrfs_file_extent_encryption(leaf, fi) ||
1306                             btrfs_file_extent_other_encoding(leaf, fi))
1307                                 goto out_check;
1308                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1309                                 goto out_check;
1310                         if (btrfs_extent_readonly(fs_info, disk_bytenr))
1311                                 goto out_check;
1312                         if (btrfs_cross_ref_exist(root, ino,
1313                                                   found_key.offset -
1314                                                   extent_offset, disk_bytenr))
1315                                 goto out_check;
1316                         disk_bytenr += extent_offset;
1317                         disk_bytenr += cur_offset - found_key.offset;
1318                         num_bytes = min(end + 1, extent_end) - cur_offset;
1319                         /*
1320                          * if there are pending snapshots for this root,
1321                          * we fall into common COW way.
1322                          */
1323                         if (!nolock) {
1324                                 err = btrfs_start_write_no_snapshoting(root);
1325                                 if (!err)
1326                                         goto out_check;
1327                         }
1328                         /*
1329                          * force cow if csum exists in the range.
1330                          * this ensure that csum for a given extent are
1331                          * either valid or do not exist.
1332                          */
1333                         if (csum_exist_in_range(fs_info, disk_bytenr,
1334                                                 num_bytes))
1335                                 goto out_check;
1336                         if (!btrfs_inc_nocow_writers(fs_info, disk_bytenr))
1337                                 goto out_check;
1338                         nocow = 1;
1339                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1340                         extent_end = found_key.offset +
1341                                 btrfs_file_extent_inline_len(leaf,
1342                                                      path->slots[0], fi);
1343                         extent_end = ALIGN(extent_end,
1344                                            fs_info->sectorsize);
1345                 } else {
1346                         BUG_ON(1);
1347                 }
1348 out_check:
1349                 if (extent_end <= start) {
1350                         path->slots[0]++;
1351                         if (!nolock && nocow)
1352                                 btrfs_end_write_no_snapshoting(root);
1353                         if (nocow)
1354                                 btrfs_dec_nocow_writers(fs_info, disk_bytenr);
1355                         goto next_slot;
1356                 }
1357                 if (!nocow) {
1358                         if (cow_start == (u64)-1)
1359                                 cow_start = cur_offset;
1360                         cur_offset = extent_end;
1361                         if (cur_offset > end)
1362                                 break;
1363                         path->slots[0]++;
1364                         goto next_slot;
1365                 }
1366
1367                 btrfs_release_path(path);
1368                 if (cow_start != (u64)-1) {
1369                         ret = cow_file_range(inode, locked_page,
1370                                              cow_start, found_key.offset - 1,
1371                                              end, page_started, nr_written, 1,
1372                                              NULL);
1373                         if (ret) {
1374                                 if (!nolock && nocow)
1375                                         btrfs_end_write_no_snapshoting(root);
1376                                 if (nocow)
1377                                         btrfs_dec_nocow_writers(fs_info,
1378                                                                 disk_bytenr);
1379                                 goto error;
1380                         }
1381                         cow_start = (u64)-1;
1382                 }
1383
1384                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1385                         u64 orig_start = found_key.offset - extent_offset;
1386
1387                         em = create_io_em(inode, cur_offset, num_bytes,
1388                                           orig_start,
1389                                           disk_bytenr, /* block_start */
1390                                           num_bytes, /* block_len */
1391                                           disk_num_bytes, /* orig_block_len */
1392                                           ram_bytes, BTRFS_COMPRESS_NONE,
1393                                           BTRFS_ORDERED_PREALLOC);
1394                         if (IS_ERR(em)) {
1395                                 if (!nolock && nocow)
1396                                         btrfs_end_write_no_snapshoting(root);
1397                                 if (nocow)
1398                                         btrfs_dec_nocow_writers(fs_info,
1399                                                                 disk_bytenr);
1400                                 ret = PTR_ERR(em);
1401                                 goto error;
1402                         }
1403                         free_extent_map(em);
1404                 }
1405
1406                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1407                         type = BTRFS_ORDERED_PREALLOC;
1408                 } else {
1409                         type = BTRFS_ORDERED_NOCOW;
1410                 }
1411
1412                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1413                                                num_bytes, num_bytes, type);
1414                 if (nocow)
1415                         btrfs_dec_nocow_writers(fs_info, disk_bytenr);
1416                 BUG_ON(ret); /* -ENOMEM */
1417
1418                 if (root->root_key.objectid ==
1419                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1420                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1421                                                       num_bytes);
1422                         if (ret) {
1423                                 if (!nolock && nocow)
1424                                         btrfs_end_write_no_snapshoting(root);
1425                                 goto error;
1426                         }
1427                 }
1428
1429                 extent_clear_unlock_delalloc(inode, cur_offset,
1430                                              cur_offset + num_bytes - 1, end,
1431                                              locked_page, EXTENT_LOCKED |
1432                                              EXTENT_DELALLOC |
1433                                              EXTENT_CLEAR_DATA_RESV,
1434                                              PAGE_UNLOCK | PAGE_SET_PRIVATE2);
1435
1436                 if (!nolock && nocow)
1437                         btrfs_end_write_no_snapshoting(root);
1438                 cur_offset = extent_end;
1439                 if (cur_offset > end)
1440                         break;
1441         }
1442         btrfs_release_path(path);
1443
1444         if (cur_offset <= end && cow_start == (u64)-1) {
1445                 cow_start = cur_offset;
1446                 cur_offset = end;
1447         }
1448
1449         if (cow_start != (u64)-1) {
1450                 ret = cow_file_range(inode, locked_page, cow_start, end, end,
1451                                      page_started, nr_written, 1, NULL);
1452                 if (ret)
1453                         goto error;
1454         }
1455
1456 error:
1457         if (ret && cur_offset < end)
1458                 extent_clear_unlock_delalloc(inode, cur_offset, end, end,
1459                                              locked_page, EXTENT_LOCKED |
1460                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1461                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1462                                              PAGE_CLEAR_DIRTY |
1463                                              PAGE_SET_WRITEBACK |
1464                                              PAGE_END_WRITEBACK);
1465         btrfs_free_path(path);
1466         return ret;
1467 }
1468
1469 static inline int need_force_cow(struct inode *inode, u64 start, u64 end)
1470 {
1471
1472         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
1473             !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC))
1474                 return 0;
1475
1476         /*
1477          * @defrag_bytes is a hint value, no spinlock held here,
1478          * if is not zero, it means the file is defragging.
1479          * Force cow if given extent needs to be defragged.
1480          */
1481         if (BTRFS_I(inode)->defrag_bytes &&
1482             test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
1483                            EXTENT_DEFRAG, 0, NULL))
1484                 return 1;
1485
1486         return 0;
1487 }
1488
1489 /*
1490  * extent_io.c call back to do delayed allocation processing
1491  */
1492 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1493                               u64 start, u64 end, int *page_started,
1494                               unsigned long *nr_written)
1495 {
1496         int ret;
1497         int force_cow = need_force_cow(inode, start, end);
1498
1499         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW && !force_cow) {
1500                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1501                                          page_started, 1, nr_written);
1502         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC && !force_cow) {
1503                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1504                                          page_started, 0, nr_written);
1505         } else if (!inode_need_compress(inode)) {
1506                 ret = cow_file_range(inode, locked_page, start, end, end,
1507                                       page_started, nr_written, 1, NULL);
1508         } else {
1509                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1510                         &BTRFS_I(inode)->runtime_flags);
1511                 ret = cow_file_range_async(inode, locked_page, start, end,
1512                                            page_started, nr_written);
1513         }
1514         return ret;
1515 }
1516
1517 static void btrfs_split_extent_hook(struct inode *inode,
1518                                     struct extent_state *orig, u64 split)
1519 {
1520         u64 size;
1521
1522         /* not delalloc, ignore it */
1523         if (!(orig->state & EXTENT_DELALLOC))
1524                 return;
1525
1526         size = orig->end - orig->start + 1;
1527         if (size > BTRFS_MAX_EXTENT_SIZE) {
1528                 u32 num_extents;
1529                 u64 new_size;
1530
1531                 /*
1532                  * See the explanation in btrfs_merge_extent_hook, the same
1533                  * applies here, just in reverse.
1534                  */
1535                 new_size = orig->end - split + 1;
1536                 num_extents = count_max_extents(new_size);
1537                 new_size = split - orig->start;
1538                 num_extents += count_max_extents(new_size);
1539                 if (count_max_extents(size) >= num_extents)
1540                         return;
1541         }
1542
1543         spin_lock(&BTRFS_I(inode)->lock);
1544         BTRFS_I(inode)->outstanding_extents++;
1545         spin_unlock(&BTRFS_I(inode)->lock);
1546 }
1547
1548 /*
1549  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1550  * extents so we can keep track of new extents that are just merged onto old
1551  * extents, such as when we are doing sequential writes, so we can properly
1552  * account for the metadata space we'll need.
1553  */
1554 static void btrfs_merge_extent_hook(struct inode *inode,
1555                                     struct extent_state *new,
1556                                     struct extent_state *other)
1557 {
1558         u64 new_size, old_size;
1559         u32 num_extents;
1560
1561         /* not delalloc, ignore it */
1562         if (!(other->state & EXTENT_DELALLOC))
1563                 return;
1564
1565         if (new->start > other->start)
1566                 new_size = new->end - other->start + 1;
1567         else
1568                 new_size = other->end - new->start + 1;
1569
1570         /* we're not bigger than the max, unreserve the space and go */
1571         if (new_size <= BTRFS_MAX_EXTENT_SIZE) {
1572                 spin_lock(&BTRFS_I(inode)->lock);
1573                 BTRFS_I(inode)->outstanding_extents--;
1574                 spin_unlock(&BTRFS_I(inode)->lock);
1575                 return;
1576         }
1577
1578         /*
1579          * We have to add up either side to figure out how many extents were
1580          * accounted for before we merged into one big extent.  If the number of
1581          * extents we accounted for is <= the amount we need for the new range
1582          * then we can return, otherwise drop.  Think of it like this
1583          *
1584          * [ 4k][MAX_SIZE]
1585          *
1586          * So we've grown the extent by a MAX_SIZE extent, this would mean we
1587          * need 2 outstanding extents, on one side we have 1 and the other side
1588          * we have 1 so they are == and we can return.  But in this case
1589          *
1590          * [MAX_SIZE+4k][MAX_SIZE+4k]
1591          *
1592          * Each range on their own accounts for 2 extents, but merged together
1593          * they are only 3 extents worth of accounting, so we need to drop in
1594          * this case.
1595          */
1596         old_size = other->end - other->start + 1;
1597         num_extents = count_max_extents(old_size);
1598         old_size = new->end - new->start + 1;
1599         num_extents += count_max_extents(old_size);
1600         if (count_max_extents(new_size) >= num_extents)
1601                 return;
1602
1603         spin_lock(&BTRFS_I(inode)->lock);
1604         BTRFS_I(inode)->outstanding_extents--;
1605         spin_unlock(&BTRFS_I(inode)->lock);
1606 }
1607
1608 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1609                                       struct inode *inode)
1610 {
1611         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1612
1613         spin_lock(&root->delalloc_lock);
1614         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1615                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1616                               &root->delalloc_inodes);
1617                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1618                         &BTRFS_I(inode)->runtime_flags);
1619                 root->nr_delalloc_inodes++;
1620                 if (root->nr_delalloc_inodes == 1) {
1621                         spin_lock(&fs_info->delalloc_root_lock);
1622                         BUG_ON(!list_empty(&root->delalloc_root));
1623                         list_add_tail(&root->delalloc_root,
1624                                       &fs_info->delalloc_roots);
1625                         spin_unlock(&fs_info->delalloc_root_lock);
1626                 }
1627         }
1628         spin_unlock(&root->delalloc_lock);
1629 }
1630
1631 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1632                                      struct inode *inode)
1633 {
1634         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1635
1636         spin_lock(&root->delalloc_lock);
1637         if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1638                 list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1639                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1640                           &BTRFS_I(inode)->runtime_flags);
1641                 root->nr_delalloc_inodes--;
1642                 if (!root->nr_delalloc_inodes) {
1643                         spin_lock(&fs_info->delalloc_root_lock);
1644                         BUG_ON(list_empty(&root->delalloc_root));
1645                         list_del_init(&root->delalloc_root);
1646                         spin_unlock(&fs_info->delalloc_root_lock);
1647                 }
1648         }
1649         spin_unlock(&root->delalloc_lock);
1650 }
1651
1652 /*
1653  * extent_io.c set_bit_hook, used to track delayed allocation
1654  * bytes in this file, and to maintain the list of inodes that
1655  * have pending delalloc work to be done.
1656  */
1657 static void btrfs_set_bit_hook(struct inode *inode,
1658                                struct extent_state *state, unsigned *bits)
1659 {
1660
1661         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1662
1663         if ((*bits & EXTENT_DEFRAG) && !(*bits & EXTENT_DELALLOC))
1664                 WARN_ON(1);
1665         /*
1666          * set_bit and clear bit hooks normally require _irqsave/restore
1667          * but in this case, we are only testing for the DELALLOC
1668          * bit, which is only set or cleared with irqs on
1669          */
1670         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1671                 struct btrfs_root *root = BTRFS_I(inode)->root;
1672                 u64 len = state->end + 1 - state->start;
1673                 bool do_list = !btrfs_is_free_space_inode(inode);
1674
1675                 if (*bits & EXTENT_FIRST_DELALLOC) {
1676                         *bits &= ~EXTENT_FIRST_DELALLOC;
1677                 } else {
1678                         spin_lock(&BTRFS_I(inode)->lock);
1679                         BTRFS_I(inode)->outstanding_extents++;
1680                         spin_unlock(&BTRFS_I(inode)->lock);
1681                 }
1682
1683                 /* For sanity tests */
1684                 if (btrfs_is_testing(fs_info))
1685                         return;
1686
1687                 __percpu_counter_add(&fs_info->delalloc_bytes, len,
1688                                      fs_info->delalloc_batch);
1689                 spin_lock(&BTRFS_I(inode)->lock);
1690                 BTRFS_I(inode)->delalloc_bytes += len;
1691                 if (*bits & EXTENT_DEFRAG)
1692                         BTRFS_I(inode)->defrag_bytes += len;
1693                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1694                                          &BTRFS_I(inode)->runtime_flags))
1695                         btrfs_add_delalloc_inodes(root, inode);
1696                 spin_unlock(&BTRFS_I(inode)->lock);
1697         }
1698 }
1699
1700 /*
1701  * extent_io.c clear_bit_hook, see set_bit_hook for why
1702  */
1703 static void btrfs_clear_bit_hook(struct inode *inode,
1704                                  struct extent_state *state,
1705                                  unsigned *bits)
1706 {
1707         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1708         u64 len = state->end + 1 - state->start;
1709         u32 num_extents = count_max_extents(len);
1710
1711         spin_lock(&BTRFS_I(inode)->lock);
1712         if ((state->state & EXTENT_DEFRAG) && (*bits & EXTENT_DEFRAG))
1713                 BTRFS_I(inode)->defrag_bytes -= len;
1714         spin_unlock(&BTRFS_I(inode)->lock);
1715
1716         /*
1717          * set_bit and clear bit hooks normally require _irqsave/restore
1718          * but in this case, we are only testing for the DELALLOC
1719          * bit, which is only set or cleared with irqs on
1720          */
1721         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1722                 struct btrfs_root *root = BTRFS_I(inode)->root;
1723                 bool do_list = !btrfs_is_free_space_inode(inode);
1724
1725                 if (*bits & EXTENT_FIRST_DELALLOC) {
1726                         *bits &= ~EXTENT_FIRST_DELALLOC;
1727                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1728                         spin_lock(&BTRFS_I(inode)->lock);
1729                         BTRFS_I(inode)->outstanding_extents -= num_extents;
1730                         spin_unlock(&BTRFS_I(inode)->lock);
1731                 }
1732
1733                 /*
1734                  * We don't reserve metadata space for space cache inodes so we
1735                  * don't need to call dellalloc_release_metadata if there is an
1736                  * error.
1737                  */
1738                 if (*bits & EXTENT_DO_ACCOUNTING &&
1739                     root != fs_info->tree_root)
1740                         btrfs_delalloc_release_metadata(inode, len);
1741
1742                 /* For sanity tests. */
1743                 if (btrfs_is_testing(fs_info))
1744                         return;
1745
1746                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1747                     && do_list && !(state->state & EXTENT_NORESERVE)
1748                     && (*bits & (EXTENT_DO_ACCOUNTING |
1749                     EXTENT_CLEAR_DATA_RESV)))
1750                         btrfs_free_reserved_data_space_noquota(inode,
1751                                         state->start, len);
1752
1753                 __percpu_counter_add(&fs_info->delalloc_bytes, -len,
1754                                      fs_info->delalloc_batch);
1755                 spin_lock(&BTRFS_I(inode)->lock);
1756                 BTRFS_I(inode)->delalloc_bytes -= len;
1757                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1758                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1759                              &BTRFS_I(inode)->runtime_flags))
1760                         btrfs_del_delalloc_inode(root, inode);
1761                 spin_unlock(&BTRFS_I(inode)->lock);
1762         }
1763 }
1764
1765 /*
1766  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1767  * we don't create bios that span stripes or chunks
1768  *
1769  * return 1 if page cannot be merged to bio
1770  * return 0 if page can be merged to bio
1771  * return error otherwise
1772  */
1773 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1774                          size_t size, struct bio *bio,
1775                          unsigned long bio_flags)
1776 {
1777         struct inode *inode = page->mapping->host;
1778         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1779         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1780         u64 length = 0;
1781         u64 map_length;
1782         int ret;
1783
1784         if (bio_flags & EXTENT_BIO_COMPRESSED)
1785                 return 0;
1786
1787         length = bio->bi_iter.bi_size;
1788         map_length = length;
1789         ret = btrfs_map_block(fs_info, btrfs_op(bio), logical, &map_length,
1790                               NULL, 0);
1791         if (ret < 0)
1792                 return ret;
1793         if (map_length < length + size)
1794                 return 1;
1795         return 0;
1796 }
1797
1798 /*
1799  * in order to insert checksums into the metadata in large chunks,
1800  * we wait until bio submission time.   All the pages in the bio are
1801  * checksummed and sums are attached onto the ordered extent record.
1802  *
1803  * At IO completion time the cums attached on the ordered extent record
1804  * are inserted into the btree
1805  */
1806 static int __btrfs_submit_bio_start(struct inode *inode, struct bio *bio,
1807                                     int mirror_num, unsigned long bio_flags,
1808                                     u64 bio_offset)
1809 {
1810         int ret = 0;
1811
1812         ret = btrfs_csum_one_bio(inode, bio, 0, 0);
1813         BUG_ON(ret); /* -ENOMEM */
1814         return 0;
1815 }
1816
1817 /*
1818  * in order to insert checksums into the metadata in large chunks,
1819  * we wait until bio submission time.   All the pages in the bio are
1820  * checksummed and sums are attached onto the ordered extent record.
1821  *
1822  * At IO completion time the cums attached on the ordered extent record
1823  * are inserted into the btree
1824  */
1825 static int __btrfs_submit_bio_done(struct inode *inode, struct bio *bio,
1826                           int mirror_num, unsigned long bio_flags,
1827                           u64 bio_offset)
1828 {
1829         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1830         int ret;
1831
1832         ret = btrfs_map_bio(fs_info, bio, mirror_num, 1);
1833         if (ret) {
1834                 bio->bi_error = ret;
1835                 bio_endio(bio);
1836         }
1837         return ret;
1838 }
1839
1840 /*
1841  * extent_io.c submission hook. This does the right thing for csum calculation
1842  * on write, or reading the csums from the tree before a read
1843  */
1844 static int btrfs_submit_bio_hook(struct inode *inode, struct bio *bio,
1845                           int mirror_num, unsigned long bio_flags,
1846                           u64 bio_offset)
1847 {
1848         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1849         struct btrfs_root *root = BTRFS_I(inode)->root;
1850         enum btrfs_wq_endio_type metadata = BTRFS_WQ_ENDIO_DATA;
1851         int ret = 0;
1852         int skip_sum;
1853         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1854
1855         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1856
1857         if (btrfs_is_free_space_inode(inode))
1858                 metadata = BTRFS_WQ_ENDIO_FREE_SPACE;
1859
1860         if (bio_op(bio) != REQ_OP_WRITE) {
1861                 ret = btrfs_bio_wq_end_io(fs_info, bio, metadata);
1862                 if (ret)
1863                         goto out;
1864
1865                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1866                         ret = btrfs_submit_compressed_read(inode, bio,
1867                                                            mirror_num,
1868                                                            bio_flags);
1869                         goto out;
1870                 } else if (!skip_sum) {
1871                         ret = btrfs_lookup_bio_sums(inode, bio, NULL);
1872                         if (ret)
1873                                 goto out;
1874                 }
1875                 goto mapit;
1876         } else if (async && !skip_sum) {
1877                 /* csum items have already been cloned */
1878                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1879                         goto mapit;
1880                 /* we're doing a write, do the async checksumming */
1881                 ret = btrfs_wq_submit_bio(fs_info, inode, bio, mirror_num,
1882                                           bio_flags, bio_offset,
1883                                           __btrfs_submit_bio_start,
1884                                           __btrfs_submit_bio_done);
1885                 goto out;
1886         } else if (!skip_sum) {
1887                 ret = btrfs_csum_one_bio(inode, bio, 0, 0);
1888                 if (ret)
1889                         goto out;
1890         }
1891
1892 mapit:
1893         ret = btrfs_map_bio(fs_info, bio, mirror_num, 0);
1894
1895 out:
1896         if (ret < 0) {
1897                 bio->bi_error = ret;
1898                 bio_endio(bio);
1899         }
1900         return ret;
1901 }
1902
1903 /*
1904  * given a list of ordered sums record them in the inode.  This happens
1905  * at IO completion time based on sums calculated at bio submission time.
1906  */
1907 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1908                              struct inode *inode, struct list_head *list)
1909 {
1910         struct btrfs_ordered_sum *sum;
1911
1912         list_for_each_entry(sum, list, list) {
1913                 trans->adding_csums = 1;
1914                 btrfs_csum_file_blocks(trans,
1915                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1916                 trans->adding_csums = 0;
1917         }
1918         return 0;
1919 }
1920
1921 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1922                               struct extent_state **cached_state, int dedupe)
1923 {
1924         WARN_ON((end & (PAGE_SIZE - 1)) == 0);
1925         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1926                                    cached_state);
1927 }
1928
1929 /* see btrfs_writepage_start_hook for details on why this is required */
1930 struct btrfs_writepage_fixup {
1931         struct page *page;
1932         struct btrfs_work work;
1933 };
1934
1935 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1936 {
1937         struct btrfs_writepage_fixup *fixup;
1938         struct btrfs_ordered_extent *ordered;
1939         struct extent_state *cached_state = NULL;
1940         struct page *page;
1941         struct inode *inode;
1942         u64 page_start;
1943         u64 page_end;
1944         int ret;
1945
1946         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1947         page = fixup->page;
1948 again:
1949         lock_page(page);
1950         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1951                 ClearPageChecked(page);
1952                 goto out_page;
1953         }
1954
1955         inode = page->mapping->host;
1956         page_start = page_offset(page);
1957         page_end = page_offset(page) + PAGE_SIZE - 1;
1958
1959         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end,
1960                          &cached_state);
1961
1962         /* already ordered? We're done */
1963         if (PagePrivate2(page))
1964                 goto out;
1965
1966         ordered = btrfs_lookup_ordered_range(inode, page_start,
1967                                         PAGE_SIZE);
1968         if (ordered) {
1969                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1970                                      page_end, &cached_state, GFP_NOFS);
1971                 unlock_page(page);
1972                 btrfs_start_ordered_extent(inode, ordered, 1);
1973                 btrfs_put_ordered_extent(ordered);
1974                 goto again;
1975         }
1976
1977         ret = btrfs_delalloc_reserve_space(inode, page_start,
1978                                            PAGE_SIZE);
1979         if (ret) {
1980                 mapping_set_error(page->mapping, ret);
1981                 end_extent_writepage(page, ret, page_start, page_end);
1982                 ClearPageChecked(page);
1983                 goto out;
1984          }
1985
1986         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state,
1987                                   0);
1988         ClearPageChecked(page);
1989         set_page_dirty(page);
1990 out:
1991         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1992                              &cached_state, GFP_NOFS);
1993 out_page:
1994         unlock_page(page);
1995         put_page(page);
1996         kfree(fixup);
1997 }
1998
1999 /*
2000  * There are a few paths in the higher layers of the kernel that directly
2001  * set the page dirty bit without asking the filesystem if it is a
2002  * good idea.  This causes problems because we want to make sure COW
2003  * properly happens and the data=ordered rules are followed.
2004  *
2005  * In our case any range that doesn't have the ORDERED bit set
2006  * hasn't been properly setup for IO.  We kick off an async process
2007  * to fix it up.  The async helper will wait for ordered extents, set
2008  * the delalloc bit and make it safe to write the page.
2009  */
2010 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
2011 {
2012         struct inode *inode = page->mapping->host;
2013         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2014         struct btrfs_writepage_fixup *fixup;
2015
2016         /* this page is properly in the ordered list */
2017         if (TestClearPagePrivate2(page))
2018                 return 0;
2019
2020         if (PageChecked(page))
2021                 return -EAGAIN;
2022
2023         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
2024         if (!fixup)
2025                 return -EAGAIN;
2026
2027         SetPageChecked(page);
2028         get_page(page);
2029         btrfs_init_work(&fixup->work, btrfs_fixup_helper,
2030                         btrfs_writepage_fixup_worker, NULL, NULL);
2031         fixup->page = page;
2032         btrfs_queue_work(fs_info->fixup_workers, &fixup->work);
2033         return -EBUSY;
2034 }
2035
2036 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
2037                                        struct inode *inode, u64 file_pos,
2038                                        u64 disk_bytenr, u64 disk_num_bytes,
2039                                        u64 num_bytes, u64 ram_bytes,
2040                                        u8 compression, u8 encryption,
2041                                        u16 other_encoding, int extent_type)
2042 {
2043         struct btrfs_root *root = BTRFS_I(inode)->root;
2044         struct btrfs_file_extent_item *fi;
2045         struct btrfs_path *path;
2046         struct extent_buffer *leaf;
2047         struct btrfs_key ins;
2048         int extent_inserted = 0;
2049         int ret;
2050
2051         path = btrfs_alloc_path();
2052         if (!path)
2053                 return -ENOMEM;
2054
2055         /*
2056          * we may be replacing one extent in the tree with another.
2057          * The new extent is pinned in the extent map, and we don't want
2058          * to drop it from the cache until it is completely in the btree.
2059          *
2060          * So, tell btrfs_drop_extents to leave this extent in the cache.
2061          * the caller is expected to unpin it and allow it to be merged
2062          * with the others.
2063          */
2064         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
2065                                    file_pos + num_bytes, NULL, 0,
2066                                    1, sizeof(*fi), &extent_inserted);
2067         if (ret)
2068                 goto out;
2069
2070         if (!extent_inserted) {
2071                 ins.objectid = btrfs_ino(BTRFS_I(inode));
2072                 ins.offset = file_pos;
2073                 ins.type = BTRFS_EXTENT_DATA_KEY;
2074
2075                 path->leave_spinning = 1;
2076                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
2077                                               sizeof(*fi));
2078                 if (ret)
2079                         goto out;
2080         }
2081         leaf = path->nodes[0];
2082         fi = btrfs_item_ptr(leaf, path->slots[0],
2083                             struct btrfs_file_extent_item);
2084         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2085         btrfs_set_file_extent_type(leaf, fi, extent_type);
2086         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
2087         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
2088         btrfs_set_file_extent_offset(leaf, fi, 0);
2089         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2090         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
2091         btrfs_set_file_extent_compression(leaf, fi, compression);
2092         btrfs_set_file_extent_encryption(leaf, fi, encryption);
2093         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
2094
2095         btrfs_mark_buffer_dirty(leaf);
2096         btrfs_release_path(path);
2097
2098         inode_add_bytes(inode, num_bytes);
2099
2100         ins.objectid = disk_bytenr;
2101         ins.offset = disk_num_bytes;
2102         ins.type = BTRFS_EXTENT_ITEM_KEY;
2103         ret = btrfs_alloc_reserved_file_extent(trans, root->root_key.objectid,
2104                         btrfs_ino(BTRFS_I(inode)), file_pos, ram_bytes, &ins);
2105         /*
2106          * Release the reserved range from inode dirty range map, as it is
2107          * already moved into delayed_ref_head
2108          */
2109         btrfs_qgroup_release_data(inode, file_pos, ram_bytes);
2110 out:
2111         btrfs_free_path(path);
2112
2113         return ret;
2114 }
2115
2116 /* snapshot-aware defrag */
2117 struct sa_defrag_extent_backref {
2118         struct rb_node node;
2119         struct old_sa_defrag_extent *old;
2120         u64 root_id;
2121         u64 inum;
2122         u64 file_pos;
2123         u64 extent_offset;
2124         u64 num_bytes;
2125         u64 generation;
2126 };
2127
2128 struct old_sa_defrag_extent {
2129         struct list_head list;
2130         struct new_sa_defrag_extent *new;
2131
2132         u64 extent_offset;
2133         u64 bytenr;
2134         u64 offset;
2135         u64 len;
2136         int count;
2137 };
2138
2139 struct new_sa_defrag_extent {
2140         struct rb_root root;
2141         struct list_head head;
2142         struct btrfs_path *path;
2143         struct inode *inode;
2144         u64 file_pos;
2145         u64 len;
2146         u64 bytenr;
2147         u64 disk_len;
2148         u8 compress_type;
2149 };
2150
2151 static int backref_comp(struct sa_defrag_extent_backref *b1,
2152                         struct sa_defrag_extent_backref *b2)
2153 {
2154         if (b1->root_id < b2->root_id)
2155                 return -1;
2156         else if (b1->root_id > b2->root_id)
2157                 return 1;
2158
2159         if (b1->inum < b2->inum)
2160                 return -1;
2161         else if (b1->inum > b2->inum)
2162                 return 1;
2163
2164         if (b1->file_pos < b2->file_pos)
2165                 return -1;
2166         else if (b1->file_pos > b2->file_pos)
2167                 return 1;
2168
2169         /*
2170          * [------------------------------] ===> (a range of space)
2171          *     |<--->|   |<---->| =============> (fs/file tree A)
2172          * |<---------------------------->| ===> (fs/file tree B)
2173          *
2174          * A range of space can refer to two file extents in one tree while
2175          * refer to only one file extent in another tree.
2176          *
2177          * So we may process a disk offset more than one time(two extents in A)
2178          * and locate at the same extent(one extent in B), then insert two same
2179          * backrefs(both refer to the extent in B).
2180          */
2181         return 0;
2182 }
2183
2184 static void backref_insert(struct rb_root *root,
2185                            struct sa_defrag_extent_backref *backref)
2186 {
2187         struct rb_node **p = &root->rb_node;
2188         struct rb_node *parent = NULL;
2189         struct sa_defrag_extent_backref *entry;
2190         int ret;
2191
2192         while (*p) {
2193                 parent = *p;
2194                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2195
2196                 ret = backref_comp(backref, entry);
2197                 if (ret < 0)
2198                         p = &(*p)->rb_left;
2199                 else
2200                         p = &(*p)->rb_right;
2201         }
2202
2203         rb_link_node(&backref->node, parent, p);
2204         rb_insert_color(&backref->node, root);
2205 }
2206
2207 /*
2208  * Note the backref might has changed, and in this case we just return 0.
2209  */
2210 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2211                                        void *ctx)
2212 {
2213         struct btrfs_file_extent_item *extent;
2214         struct old_sa_defrag_extent *old = ctx;
2215         struct new_sa_defrag_extent *new = old->new;
2216         struct btrfs_path *path = new->path;
2217         struct btrfs_key key;
2218         struct btrfs_root *root;
2219         struct sa_defrag_extent_backref *backref;
2220         struct extent_buffer *leaf;
2221         struct inode *inode = new->inode;
2222         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2223         int slot;
2224         int ret;
2225         u64 extent_offset;
2226         u64 num_bytes;
2227
2228         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2229             inum == btrfs_ino(BTRFS_I(inode)))
2230                 return 0;
2231
2232         key.objectid = root_id;
2233         key.type = BTRFS_ROOT_ITEM_KEY;
2234         key.offset = (u64)-1;
2235
2236         root = btrfs_read_fs_root_no_name(fs_info, &key);
2237         if (IS_ERR(root)) {
2238                 if (PTR_ERR(root) == -ENOENT)
2239                         return 0;
2240                 WARN_ON(1);
2241                 btrfs_debug(fs_info, "inum=%llu, offset=%llu, root_id=%llu",
2242                          inum, offset, root_id);
2243                 return PTR_ERR(root);
2244         }
2245
2246         key.objectid = inum;
2247         key.type = BTRFS_EXTENT_DATA_KEY;
2248         if (offset > (u64)-1 << 32)
2249                 key.offset = 0;
2250         else
2251                 key.offset = offset;
2252
2253         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2254         if (WARN_ON(ret < 0))
2255                 return ret;
2256         ret = 0;
2257
2258         while (1) {
2259                 cond_resched();
2260
2261                 leaf = path->nodes[0];
2262                 slot = path->slots[0];
2263
2264                 if (slot >= btrfs_header_nritems(leaf)) {
2265                         ret = btrfs_next_leaf(root, path);
2266                         if (ret < 0) {
2267                                 goto out;
2268                         } else if (ret > 0) {
2269                                 ret = 0;
2270                                 goto out;
2271                         }
2272                         continue;
2273                 }
2274
2275                 path->slots[0]++;
2276
2277                 btrfs_item_key_to_cpu(leaf, &key, slot);
2278
2279                 if (key.objectid > inum)
2280                         goto out;
2281
2282                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2283                         continue;
2284
2285                 extent = btrfs_item_ptr(leaf, slot,
2286                                         struct btrfs_file_extent_item);
2287
2288                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2289                         continue;
2290
2291                 /*
2292                  * 'offset' refers to the exact key.offset,
2293                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2294                  * (key.offset - extent_offset).
2295                  */
2296                 if (key.offset != offset)
2297                         continue;
2298
2299                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2300                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2301
2302                 if (extent_offset >= old->extent_offset + old->offset +
2303                     old->len || extent_offset + num_bytes <=
2304                     old->extent_offset + old->offset)
2305                         continue;
2306                 break;
2307         }
2308
2309         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2310         if (!backref) {
2311                 ret = -ENOENT;
2312                 goto out;
2313         }
2314
2315         backref->root_id = root_id;
2316         backref->inum = inum;
2317         backref->file_pos = offset;
2318         backref->num_bytes = num_bytes;
2319         backref->extent_offset = extent_offset;
2320         backref->generation = btrfs_file_extent_generation(leaf, extent);
2321         backref->old = old;
2322         backref_insert(&new->root, backref);
2323         old->count++;
2324 out:
2325         btrfs_release_path(path);
2326         WARN_ON(ret);
2327         return ret;
2328 }
2329
2330 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2331                                    struct new_sa_defrag_extent *new)
2332 {
2333         struct btrfs_fs_info *fs_info = btrfs_sb(new->inode->i_sb);
2334         struct old_sa_defrag_extent *old, *tmp;
2335         int ret;
2336
2337         new->path = path;
2338
2339         list_for_each_entry_safe(old, tmp, &new->head, list) {
2340                 ret = iterate_inodes_from_logical(old->bytenr +
2341                                                   old->extent_offset, fs_info,
2342                                                   path, record_one_backref,
2343                                                   old);
2344                 if (ret < 0 && ret != -ENOENT)
2345                         return false;
2346
2347                 /* no backref to be processed for this extent */
2348                 if (!old->count) {
2349                         list_del(&old->list);
2350                         kfree(old);
2351                 }
2352         }
2353
2354         if (list_empty(&new->head))
2355                 return false;
2356
2357         return true;
2358 }
2359
2360 static int relink_is_mergable(struct extent_buffer *leaf,
2361                               struct btrfs_file_extent_item *fi,
2362                               struct new_sa_defrag_extent *new)
2363 {
2364         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2365                 return 0;
2366
2367         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2368                 return 0;
2369
2370         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2371                 return 0;
2372
2373         if (btrfs_file_extent_encryption(leaf, fi) ||
2374             btrfs_file_extent_other_encoding(leaf, fi))
2375                 return 0;
2376
2377         return 1;
2378 }
2379
2380 /*
2381  * Note the backref might has changed, and in this case we just return 0.
2382  */
2383 static noinline int relink_extent_backref(struct btrfs_path *path,
2384                                  struct sa_defrag_extent_backref *prev,
2385                                  struct sa_defrag_extent_backref *backref)
2386 {
2387         struct btrfs_file_extent_item *extent;
2388         struct btrfs_file_extent_item *item;
2389         struct btrfs_ordered_extent *ordered;
2390         struct btrfs_trans_handle *trans;
2391         struct btrfs_root *root;
2392         struct btrfs_key key;
2393         struct extent_buffer *leaf;
2394         struct old_sa_defrag_extent *old = backref->old;
2395         struct new_sa_defrag_extent *new = old->new;
2396         struct btrfs_fs_info *fs_info = btrfs_sb(new->inode->i_sb);
2397         struct inode *inode;
2398         struct extent_state *cached = NULL;
2399         int ret = 0;
2400         u64 start;
2401         u64 len;
2402         u64 lock_start;
2403         u64 lock_end;
2404         bool merge = false;
2405         int index;
2406
2407         if (prev && prev->root_id == backref->root_id &&
2408             prev->inum == backref->inum &&
2409             prev->file_pos + prev->num_bytes == backref->file_pos)
2410                 merge = true;
2411
2412         /* step 1: get root */
2413         key.objectid = backref->root_id;
2414         key.type = BTRFS_ROOT_ITEM_KEY;
2415         key.offset = (u64)-1;
2416
2417         index = srcu_read_lock(&fs_info->subvol_srcu);
2418
2419         root = btrfs_read_fs_root_no_name(fs_info, &key);
2420         if (IS_ERR(root)) {
2421                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2422                 if (PTR_ERR(root) == -ENOENT)
2423                         return 0;
2424                 return PTR_ERR(root);
2425         }
2426
2427         if (btrfs_root_readonly(root)) {
2428                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2429                 return 0;
2430         }
2431
2432         /* step 2: get inode */
2433         key.objectid = backref->inum;
2434         key.type = BTRFS_INODE_ITEM_KEY;
2435         key.offset = 0;
2436
2437         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2438         if (IS_ERR(inode)) {
2439                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2440                 return 0;
2441         }
2442
2443         srcu_read_unlock(&fs_info->subvol_srcu, index);
2444
2445         /* step 3: relink backref */
2446         lock_start = backref->file_pos;
2447         lock_end = backref->file_pos + backref->num_bytes - 1;
2448         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2449                          &cached);
2450
2451         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2452         if (ordered) {
2453                 btrfs_put_ordered_extent(ordered);
2454                 goto out_unlock;
2455         }
2456
2457         trans = btrfs_join_transaction(root);
2458         if (IS_ERR(trans)) {
2459                 ret = PTR_ERR(trans);
2460                 goto out_unlock;
2461         }
2462
2463         key.objectid = backref->inum;
2464         key.type = BTRFS_EXTENT_DATA_KEY;
2465         key.offset = backref->file_pos;
2466
2467         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2468         if (ret < 0) {
2469                 goto out_free_path;
2470         } else if (ret > 0) {
2471                 ret = 0;
2472                 goto out_free_path;
2473         }
2474
2475         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2476                                 struct btrfs_file_extent_item);
2477
2478         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2479             backref->generation)
2480                 goto out_free_path;
2481
2482         btrfs_release_path(path);
2483
2484         start = backref->file_pos;
2485         if (backref->extent_offset < old->extent_offset + old->offset)
2486                 start += old->extent_offset + old->offset -
2487                          backref->extent_offset;
2488
2489         len = min(backref->extent_offset + backref->num_bytes,
2490                   old->extent_offset + old->offset + old->len);
2491         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2492
2493         ret = btrfs_drop_extents(trans, root, inode, start,
2494                                  start + len, 1);
2495         if (ret)
2496                 goto out_free_path;
2497 again:
2498         key.objectid = btrfs_ino(BTRFS_I(inode));
2499         key.type = BTRFS_EXTENT_DATA_KEY;
2500         key.offset = start;
2501
2502         path->leave_spinning = 1;
2503         if (merge) {
2504                 struct btrfs_file_extent_item *fi;
2505                 u64 extent_len;
2506                 struct btrfs_key found_key;
2507
2508                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2509                 if (ret < 0)
2510                         goto out_free_path;
2511
2512                 path->slots[0]--;
2513                 leaf = path->nodes[0];
2514                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2515
2516                 fi = btrfs_item_ptr(leaf, path->slots[0],
2517                                     struct btrfs_file_extent_item);
2518                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2519
2520                 if (extent_len + found_key.offset == start &&
2521                     relink_is_mergable(leaf, fi, new)) {
2522                         btrfs_set_file_extent_num_bytes(leaf, fi,
2523                                                         extent_len + len);
2524                         btrfs_mark_buffer_dirty(leaf);
2525                         inode_add_bytes(inode, len);
2526
2527                         ret = 1;
2528                         goto out_free_path;
2529                 } else {
2530                         merge = false;
2531                         btrfs_release_path(path);
2532                         goto again;
2533                 }
2534         }
2535
2536         ret = btrfs_insert_empty_item(trans, root, path, &key,
2537                                         sizeof(*extent));
2538         if (ret) {
2539                 btrfs_abort_transaction(trans, ret);
2540                 goto out_free_path;
2541         }
2542
2543         leaf = path->nodes[0];
2544         item = btrfs_item_ptr(leaf, path->slots[0],
2545                                 struct btrfs_file_extent_item);
2546         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2547         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2548         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2549         btrfs_set_file_extent_num_bytes(leaf, item, len);
2550         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2551         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2552         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2553         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2554         btrfs_set_file_extent_encryption(leaf, item, 0);
2555         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2556
2557         btrfs_mark_buffer_dirty(leaf);
2558         inode_add_bytes(inode, len);
2559         btrfs_release_path(path);
2560
2561         ret = btrfs_inc_extent_ref(trans, fs_info, new->bytenr,
2562                         new->disk_len, 0,
2563                         backref->root_id, backref->inum,
2564                         new->file_pos); /* start - extent_offset */
2565         if (ret) {
2566                 btrfs_abort_transaction(trans, ret);
2567                 goto out_free_path;
2568         }
2569
2570         ret = 1;
2571 out_free_path:
2572         btrfs_release_path(path);
2573         path->leave_spinning = 0;
2574         btrfs_end_transaction(trans);
2575 out_unlock:
2576         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2577                              &cached, GFP_NOFS);
2578         iput(inode);
2579         return ret;
2580 }
2581
2582 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2583 {
2584         struct old_sa_defrag_extent *old, *tmp;
2585
2586         if (!new)
2587                 return;
2588
2589         list_for_each_entry_safe(old, tmp, &new->head, list) {
2590                 kfree(old);
2591         }
2592         kfree(new);
2593 }
2594
2595 static void relink_file_extents(struct new_sa_defrag_extent *new)
2596 {
2597         struct btrfs_fs_info *fs_info = btrfs_sb(new->inode->i_sb);
2598         struct btrfs_path *path;
2599         struct sa_defrag_extent_backref *backref;
2600         struct sa_defrag_extent_backref *prev = NULL;
2601         struct inode *inode;
2602         struct btrfs_root *root;
2603         struct rb_node *node;
2604         int ret;
2605
2606         inode = new->inode;
2607         root = BTRFS_I(inode)->root;
2608
2609         path = btrfs_alloc_path();
2610         if (!path)
2611                 return;
2612
2613         if (!record_extent_backrefs(path, new)) {
2614                 btrfs_free_path(path);
2615                 goto out;
2616         }
2617         btrfs_release_path(path);
2618
2619         while (1) {
2620                 node = rb_first(&new->root);
2621                 if (!node)
2622                         break;
2623                 rb_erase(node, &new->root);
2624
2625                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2626
2627                 ret = relink_extent_backref(path, prev, backref);
2628                 WARN_ON(ret < 0);
2629
2630                 kfree(prev);
2631
2632                 if (ret == 1)
2633                         prev = backref;
2634                 else
2635                         prev = NULL;
2636                 cond_resched();
2637         }
2638         kfree(prev);
2639
2640         btrfs_free_path(path);
2641 out:
2642         free_sa_defrag_extent(new);
2643
2644         atomic_dec(&fs_info->defrag_running);
2645         wake_up(&fs_info->transaction_wait);
2646 }
2647
2648 static struct new_sa_defrag_extent *
2649 record_old_file_extents(struct inode *inode,
2650                         struct btrfs_ordered_extent *ordered)
2651 {
2652         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2653         struct btrfs_root *root = BTRFS_I(inode)->root;
2654         struct btrfs_path *path;
2655         struct btrfs_key key;
2656         struct old_sa_defrag_extent *old;
2657         struct new_sa_defrag_extent *new;
2658         int ret;
2659
2660         new = kmalloc(sizeof(*new), GFP_NOFS);
2661         if (!new)
2662                 return NULL;
2663
2664         new->inode = inode;
2665         new->file_pos = ordered->file_offset;
2666         new->len = ordered->len;
2667         new->bytenr = ordered->start;
2668         new->disk_len = ordered->disk_len;
2669         new->compress_type = ordered->compress_type;
2670         new->root = RB_ROOT;
2671         INIT_LIST_HEAD(&new->head);
2672
2673         path = btrfs_alloc_path();
2674         if (!path)
2675                 goto out_kfree;
2676
2677         key.objectid = btrfs_ino(BTRFS_I(inode));
2678         key.type = BTRFS_EXTENT_DATA_KEY;
2679         key.offset = new->file_pos;
2680
2681         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2682         if (ret < 0)
2683                 goto out_free_path;
2684         if (ret > 0 && path->slots[0] > 0)
2685                 path->slots[0]--;
2686
2687         /* find out all the old extents for the file range */
2688         while (1) {
2689                 struct btrfs_file_extent_item *extent;
2690                 struct extent_buffer *l;
2691                 int slot;
2692                 u64 num_bytes;
2693                 u64 offset;
2694                 u64 end;
2695                 u64 disk_bytenr;
2696                 u64 extent_offset;
2697
2698                 l = path->nodes[0];
2699                 slot = path->slots[0];
2700
2701                 if (slot >= btrfs_header_nritems(l)) {
2702                         ret = btrfs_next_leaf(root, path);
2703                         if (ret < 0)
2704                                 goto out_free_path;
2705                         else if (ret > 0)
2706                                 break;
2707                         continue;
2708                 }
2709
2710                 btrfs_item_key_to_cpu(l, &key, slot);
2711
2712                 if (key.objectid != btrfs_ino(BTRFS_I(inode)))
2713                         break;
2714                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2715                         break;
2716                 if (key.offset >= new->file_pos + new->len)
2717                         break;
2718
2719                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2720
2721                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2722                 if (key.offset + num_bytes < new->file_pos)
2723                         goto next;
2724
2725                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2726                 if (!disk_bytenr)
2727                         goto next;
2728
2729                 extent_offset = btrfs_file_extent_offset(l, extent);
2730
2731                 old = kmalloc(sizeof(*old), GFP_NOFS);
2732                 if (!old)
2733                         goto out_free_path;
2734
2735                 offset = max(new->file_pos, key.offset);
2736                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2737
2738                 old->bytenr = disk_bytenr;
2739                 old->extent_offset = extent_offset;
2740                 old->offset = offset - key.offset;
2741                 old->len = end - offset;
2742                 old->new = new;
2743                 old->count = 0;
2744                 list_add_tail(&old->list, &new->head);
2745 next:
2746                 path->slots[0]++;
2747                 cond_resched();
2748         }
2749
2750         btrfs_free_path(path);
2751         atomic_inc(&fs_info->defrag_running);
2752
2753         return new;
2754
2755 out_free_path:
2756         btrfs_free_path(path);
2757 out_kfree:
2758         free_sa_defrag_extent(new);
2759         return NULL;
2760 }
2761
2762 static void btrfs_release_delalloc_bytes(struct btrfs_fs_info *fs_info,
2763                                          u64 start, u64 len)
2764 {
2765         struct btrfs_block_group_cache *cache;
2766
2767         cache = btrfs_lookup_block_group(fs_info, start);
2768         ASSERT(cache);
2769
2770         spin_lock(&cache->lock);
2771         cache->delalloc_bytes -= len;
2772         spin_unlock(&cache->lock);
2773
2774         btrfs_put_block_group(cache);
2775 }
2776
2777 /* as ordered data IO finishes, this gets called so we can finish
2778  * an ordered extent if the range of bytes in the file it covers are
2779  * fully written.
2780  */
2781 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2782 {
2783         struct inode *inode = ordered_extent->inode;
2784         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2785         struct btrfs_root *root = BTRFS_I(inode)->root;
2786         struct btrfs_trans_handle *trans = NULL;
2787         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2788         struct extent_state *cached_state = NULL;
2789         struct new_sa_defrag_extent *new = NULL;
2790         int compress_type = 0;
2791         int ret = 0;
2792         u64 logical_len = ordered_extent->len;
2793         bool nolock;
2794         bool truncated = false;
2795
2796         nolock = btrfs_is_free_space_inode(inode);
2797
2798         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2799                 ret = -EIO;
2800                 goto out;
2801         }
2802
2803         btrfs_free_io_failure_record(inode, ordered_extent->file_offset,
2804                                      ordered_extent->file_offset +
2805                                      ordered_extent->len - 1);
2806
2807         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2808                 truncated = true;
2809                 logical_len = ordered_extent->truncated_len;
2810                 /* Truncated the entire extent, don't bother adding */
2811                 if (!logical_len)
2812                         goto out;
2813         }
2814
2815         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2816                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2817
2818                 /*
2819                  * For mwrite(mmap + memset to write) case, we still reserve
2820                  * space for NOCOW range.
2821                  * As NOCOW won't cause a new delayed ref, just free the space
2822                  */
2823                 btrfs_qgroup_free_data(inode, ordered_extent->file_offset,
2824                                        ordered_extent->len);
2825                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2826                 if (nolock)
2827                         trans = btrfs_join_transaction_nolock(root);
2828                 else
2829                         trans = btrfs_join_transaction(root);
2830                 if (IS_ERR(trans)) {
2831                         ret = PTR_ERR(trans);
2832                         trans = NULL;
2833                         goto out;
2834                 }
2835                 trans->block_rsv = &fs_info->delalloc_block_rsv;
2836                 ret = btrfs_update_inode_fallback(trans, root, inode);
2837                 if (ret) /* -ENOMEM or corruption */
2838                         btrfs_abort_transaction(trans, ret);
2839                 goto out;
2840         }
2841
2842         lock_extent_bits(io_tree, ordered_extent->file_offset,
2843                          ordered_extent->file_offset + ordered_extent->len - 1,
2844                          &cached_state);
2845
2846         ret = test_range_bit(io_tree, ordered_extent->file_offset,
2847                         ordered_extent->file_offset + ordered_extent->len - 1,
2848                         EXTENT_DEFRAG, 1, cached_state);
2849         if (ret) {
2850                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2851                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
2852                         /* the inode is shared */
2853                         new = record_old_file_extents(inode, ordered_extent);
2854
2855                 clear_extent_bit(io_tree, ordered_extent->file_offset,
2856                         ordered_extent->file_offset + ordered_extent->len - 1,
2857                         EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS);
2858         }
2859
2860         if (nolock)
2861                 trans = btrfs_join_transaction_nolock(root);
2862         else
2863                 trans = btrfs_join_transaction(root);
2864         if (IS_ERR(trans)) {
2865                 ret = PTR_ERR(trans);
2866                 trans = NULL;
2867                 goto out_unlock;
2868         }
2869
2870         trans->block_rsv = &fs_info->delalloc_block_rsv;
2871
2872         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2873                 compress_type = ordered_extent->compress_type;
2874         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2875                 BUG_ON(compress_type);
2876                 ret = btrfs_mark_extent_written(trans, inode,
2877                                                 ordered_extent->file_offset,
2878                                                 ordered_extent->file_offset +
2879                                                 logical_len);
2880         } else {
2881                 BUG_ON(root == fs_info->tree_root);
2882                 ret = insert_reserved_file_extent(trans, inode,
2883                                                 ordered_extent->file_offset,
2884                                                 ordered_extent->start,
2885                                                 ordered_extent->disk_len,
2886                                                 logical_len, logical_len,
2887                                                 compress_type, 0, 0,
2888                                                 BTRFS_FILE_EXTENT_REG);
2889                 if (!ret)
2890                         btrfs_release_delalloc_bytes(fs_info,
2891                                                      ordered_extent->start,
2892                                                      ordered_extent->disk_len);
2893         }
2894         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2895                            ordered_extent->file_offset, ordered_extent->len,
2896                            trans->transid);
2897         if (ret < 0) {
2898                 btrfs_abort_transaction(trans, ret);
2899                 goto out_unlock;
2900         }
2901
2902         add_pending_csums(trans, inode, &ordered_extent->list);
2903
2904         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2905         ret = btrfs_update_inode_fallback(trans, root, inode);
2906         if (ret) { /* -ENOMEM or corruption */
2907                 btrfs_abort_transaction(trans, ret);
2908                 goto out_unlock;
2909         }
2910         ret = 0;
2911 out_unlock:
2912         unlock_extent_cached(io_tree, ordered_extent->file_offset,
2913                              ordered_extent->file_offset +
2914                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
2915 out:
2916         if (root != fs_info->tree_root)
2917                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
2918         if (trans)
2919                 btrfs_end_transaction(trans);
2920
2921         if (ret || truncated) {
2922                 u64 start, end;
2923
2924                 if (truncated)
2925                         start = ordered_extent->file_offset + logical_len;
2926                 else
2927                         start = ordered_extent->file_offset;
2928                 end = ordered_extent->file_offset + ordered_extent->len - 1;
2929                 clear_extent_uptodate(io_tree, start, end, NULL, GFP_NOFS);
2930
2931                 /* Drop the cache for the part of the extent we didn't write. */
2932                 btrfs_drop_extent_cache(inode, start, end, 0);
2933
2934                 /*
2935                  * If the ordered extent had an IOERR or something else went
2936                  * wrong we need to return the space for this ordered extent
2937                  * back to the allocator.  We only free the extent in the
2938                  * truncated case if we didn't write out the extent at all.
2939                  */
2940                 if ((ret || !logical_len) &&
2941                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2942                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
2943                         btrfs_free_reserved_extent(fs_info,
2944                                                    ordered_extent->start,
2945                                                    ordered_extent->disk_len, 1);
2946         }
2947
2948
2949         /*
2950          * This needs to be done to make sure anybody waiting knows we are done
2951          * updating everything for this ordered extent.
2952          */
2953         btrfs_remove_ordered_extent(inode, ordered_extent);
2954
2955         /* for snapshot-aware defrag */
2956         if (new) {
2957                 if (ret) {
2958                         free_sa_defrag_extent(new);
2959                         atomic_dec(&fs_info->defrag_running);
2960                 } else {
2961                         relink_file_extents(new);
2962                 }
2963         }
2964
2965         /* once for us */
2966         btrfs_put_ordered_extent(ordered_extent);
2967         /* once for the tree */
2968         btrfs_put_ordered_extent(ordered_extent);
2969
2970         return ret;
2971 }
2972
2973 static void finish_ordered_fn(struct btrfs_work *work)
2974 {
2975         struct btrfs_ordered_extent *ordered_extent;
2976         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
2977         btrfs_finish_ordered_io(ordered_extent);
2978 }
2979
2980 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
2981                                 struct extent_state *state, int uptodate)
2982 {
2983         struct inode *inode = page->mapping->host;
2984         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2985         struct btrfs_ordered_extent *ordered_extent = NULL;
2986         struct btrfs_workqueue *wq;
2987         btrfs_work_func_t func;
2988
2989         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
2990
2991         ClearPagePrivate2(page);
2992         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
2993                                             end - start + 1, uptodate))
2994                 return 0;
2995
2996         if (btrfs_is_free_space_inode(inode)) {
2997                 wq = fs_info->endio_freespace_worker;
2998                 func = btrfs_freespace_write_helper;
2999         } else {
3000                 wq = fs_info->endio_write_workers;
3001                 func = btrfs_endio_write_helper;
3002         }
3003
3004         btrfs_init_work(&ordered_extent->work, func, finish_ordered_fn, NULL,
3005                         NULL);
3006         btrfs_queue_work(wq, &ordered_extent->work);
3007
3008         return 0;
3009 }
3010
3011 static int __readpage_endio_check(struct inode *inode,
3012                                   struct btrfs_io_bio *io_bio,
3013                                   int icsum, struct page *page,
3014                                   int pgoff, u64 start, size_t len)
3015 {
3016         char *kaddr;
3017         u32 csum_expected;
3018         u32 csum = ~(u32)0;
3019
3020         csum_expected = *(((u32 *)io_bio->csum) + icsum);
3021
3022         kaddr = kmap_atomic(page);
3023         csum = btrfs_csum_data(kaddr + pgoff, csum,  len);
3024         btrfs_csum_final(csum, (u8 *)&csum);
3025         if (csum != csum_expected)
3026                 goto zeroit;
3027
3028         kunmap_atomic(kaddr);
3029         return 0;
3030 zeroit:
3031         btrfs_print_data_csum_error(inode, start, csum, csum_expected,
3032                                     io_bio->mirror_num);
3033         memset(kaddr + pgoff, 1, len);
3034         flush_dcache_page(page);
3035         kunmap_atomic(kaddr);
3036         if (csum_expected == 0)
3037                 return 0;
3038         return -EIO;
3039 }
3040
3041 /*
3042  * when reads are done, we need to check csums to verify the data is correct
3043  * if there's a match, we allow the bio to finish.  If not, the code in
3044  * extent_io.c will try to find good copies for us.
3045  */
3046 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
3047                                       u64 phy_offset, struct page *page,
3048                                       u64 start, u64 end, int mirror)
3049 {
3050         size_t offset = start - page_offset(page);
3051         struct inode *inode = page->mapping->host;
3052         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3053         struct btrfs_root *root = BTRFS_I(inode)->root;
3054
3055         if (PageChecked(page)) {
3056                 ClearPageChecked(page);
3057                 return 0;
3058         }
3059
3060         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
3061                 return 0;
3062
3063         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
3064             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
3065                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM);
3066                 return 0;
3067         }
3068
3069         phy_offset >>= inode->i_sb->s_blocksize_bits;
3070         return __readpage_endio_check(inode, io_bio, phy_offset, page, offset,
3071                                       start, (size_t)(end - start + 1));
3072 }
3073
3074 void btrfs_add_delayed_iput(struct inode *inode)
3075 {
3076         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3077         struct btrfs_inode *binode = BTRFS_I(inode);
3078
3079         if (atomic_add_unless(&inode->i_count, -1, 1))
3080                 return;
3081
3082         spin_lock(&fs_info->delayed_iput_lock);
3083         if (binode->delayed_iput_count == 0) {
3084                 ASSERT(list_empty(&binode->delayed_iput));
3085                 list_add_tail(&binode->delayed_iput, &fs_info->delayed_iputs);
3086         } else {
3087                 binode->delayed_iput_count++;
3088         }
3089         spin_unlock(&fs_info->delayed_iput_lock);
3090 }
3091
3092 void btrfs_run_delayed_iputs(struct btrfs_fs_info *fs_info)
3093 {
3094
3095         spin_lock(&fs_info->delayed_iput_lock);
3096         while (!list_empty(&fs_info->delayed_iputs)) {
3097                 struct btrfs_inode *inode;
3098
3099                 inode = list_first_entry(&fs_info->delayed_iputs,
3100                                 struct btrfs_inode, delayed_iput);
3101                 if (inode->delayed_iput_count) {
3102                         inode->delayed_iput_count--;
3103                         list_move_tail(&inode->delayed_iput,
3104                                         &fs_info->delayed_iputs);
3105                 } else {
3106                         list_del_init(&inode->delayed_iput);
3107                 }
3108                 spin_unlock(&fs_info->delayed_iput_lock);
3109                 iput(&inode->vfs_inode);
3110                 spin_lock(&fs_info->delayed_iput_lock);
3111         }
3112         spin_unlock(&fs_info->delayed_iput_lock);
3113 }
3114
3115 /*
3116  * This is called in transaction commit time. If there are no orphan
3117  * files in the subvolume, it removes orphan item and frees block_rsv
3118  * structure.
3119  */
3120 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
3121                               struct btrfs_root *root)
3122 {
3123         struct btrfs_fs_info *fs_info = root->fs_info;
3124         struct btrfs_block_rsv *block_rsv;
3125         int ret;
3126
3127         if (atomic_read(&root->orphan_inodes) ||
3128             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
3129                 return;
3130
3131         spin_lock(&root->orphan_lock);
3132         if (atomic_read(&root->orphan_inodes)) {
3133                 spin_unlock(&root->orphan_lock);
3134                 return;
3135         }
3136
3137         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
3138                 spin_unlock(&root->orphan_lock);
3139                 return;
3140         }
3141
3142         block_rsv = root->orphan_block_rsv;
3143         root->orphan_block_rsv = NULL;
3144         spin_unlock(&root->orphan_lock);
3145
3146         if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state) &&
3147             btrfs_root_refs(&root->root_item) > 0) {
3148                 ret = btrfs_del_orphan_item(trans, fs_info->tree_root,
3149                                             root->root_key.objectid);
3150                 if (ret)
3151                         btrfs_abort_transaction(trans, ret);
3152                 else
3153                         clear_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
3154                                   &root->state);
3155         }
3156
3157         if (block_rsv) {
3158                 WARN_ON(block_rsv->size > 0);
3159                 btrfs_free_block_rsv(fs_info, block_rsv);
3160         }
3161 }
3162
3163 /*
3164  * This creates an orphan entry for the given inode in case something goes
3165  * wrong in the middle of an unlink/truncate.
3166  *
3167  * NOTE: caller of this function should reserve 5 units of metadata for
3168  *       this function.
3169  */
3170 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
3171 {
3172         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3173         struct btrfs_root *root = BTRFS_I(inode)->root;
3174         struct btrfs_block_rsv *block_rsv = NULL;
3175         int reserve = 0;
3176         int insert = 0;
3177         int ret;
3178
3179         if (!root->orphan_block_rsv) {
3180                 block_rsv = btrfs_alloc_block_rsv(fs_info,
3181                                                   BTRFS_BLOCK_RSV_TEMP);
3182                 if (!block_rsv)
3183                         return -ENOMEM;
3184         }
3185
3186         spin_lock(&root->orphan_lock);
3187         if (!root->orphan_block_rsv) {
3188                 root->orphan_block_rsv = block_rsv;
3189         } else if (block_rsv) {
3190                 btrfs_free_block_rsv(fs_info, block_rsv);
3191                 block_rsv = NULL;
3192         }
3193
3194         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3195                               &BTRFS_I(inode)->runtime_flags)) {
3196 #if 0
3197                 /*
3198                  * For proper ENOSPC handling, we should do orphan
3199                  * cleanup when mounting. But this introduces backward
3200                  * compatibility issue.
3201                  */
3202                 if (!xchg(&root->orphan_item_inserted, 1))
3203                         insert = 2;
3204                 else
3205                         insert = 1;
3206 #endif
3207                 insert = 1;
3208                 atomic_inc(&root->orphan_inodes);
3209         }
3210
3211         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3212                               &BTRFS_I(inode)->runtime_flags))
3213                 reserve = 1;
3214         spin_unlock(&root->orphan_lock);
3215
3216         /* grab metadata reservation from transaction handle */
3217         if (reserve) {
3218                 ret = btrfs_orphan_reserve_metadata(trans, inode);
3219                 ASSERT(!ret);
3220                 if (ret) {
3221                         atomic_dec(&root->orphan_inodes);
3222                         clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3223                                   &BTRFS_I(inode)->runtime_flags);
3224                         if (insert)
3225                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3226                                           &BTRFS_I(inode)->runtime_flags);
3227                         return ret;
3228                 }
3229         }
3230
3231         /* insert an orphan item to track this unlinked/truncated file */
3232         if (insert >= 1) {
3233                 ret = btrfs_insert_orphan_item(trans, root,
3234                                 btrfs_ino(BTRFS_I(inode)));
3235                 if (ret) {
3236                         atomic_dec(&root->orphan_inodes);
3237                         if (reserve) {
3238                                 clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3239                                           &BTRFS_I(inode)->runtime_flags);
3240                                 btrfs_orphan_release_metadata(inode);
3241                         }
3242                         if (ret != -EEXIST) {
3243                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3244                                           &BTRFS_I(inode)->runtime_flags);
3245                                 btrfs_abort_transaction(trans, ret);
3246                                 return ret;
3247                         }
3248                 }
3249                 ret = 0;
3250         }
3251
3252         /* insert an orphan item to track subvolume contains orphan files */
3253         if (insert >= 2) {
3254                 ret = btrfs_insert_orphan_item(trans, fs_info->tree_root,
3255                                                root->root_key.objectid);
3256                 if (ret && ret != -EEXIST) {
3257                         btrfs_abort_transaction(trans, ret);
3258                         return ret;
3259                 }
3260         }
3261         return 0;
3262 }
3263
3264 /*
3265  * We have done the truncate/delete so we can go ahead and remove the orphan
3266  * item for this particular inode.
3267  */
3268 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3269                             struct inode *inode)
3270 {
3271         struct btrfs_root *root = BTRFS_I(inode)->root;
3272         int delete_item = 0;
3273         int release_rsv = 0;
3274         int ret = 0;
3275
3276         spin_lock(&root->orphan_lock);
3277         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3278                                &BTRFS_I(inode)->runtime_flags))
3279                 delete_item = 1;
3280
3281         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3282                                &BTRFS_I(inode)->runtime_flags))
3283                 release_rsv = 1;
3284         spin_unlock(&root->orphan_lock);
3285
3286         if (delete_item) {
3287                 atomic_dec(&root->orphan_inodes);
3288                 if (trans)
3289                         ret = btrfs_del_orphan_item(trans, root,
3290                                                     btrfs_ino(BTRFS_I(inode)));
3291         }
3292
3293         if (release_rsv)
3294                 btrfs_orphan_release_metadata(inode);
3295
3296         return ret;
3297 }
3298
3299 /*
3300  * this cleans up any orphans that may be left on the list from the last use
3301  * of this root.
3302  */
3303 int btrfs_orphan_cleanup(struct btrfs_root *root)
3304 {
3305         struct btrfs_fs_info *fs_info = root->fs_info;
3306         struct btrfs_path *path;
3307         struct extent_buffer *leaf;
3308         struct btrfs_key key, found_key;
3309         struct btrfs_trans_handle *trans;
3310         struct inode *inode;
3311         u64 last_objectid = 0;
3312         int ret = 0, nr_unlink = 0, nr_truncate = 0;
3313
3314         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3315                 return 0;
3316
3317         path = btrfs_alloc_path();
3318         if (!path) {
3319                 ret = -ENOMEM;
3320                 goto out;
3321         }
3322         path->reada = READA_BACK;
3323
3324         key.objectid = BTRFS_ORPHAN_OBJECTID;
3325         key.type = BTRFS_ORPHAN_ITEM_KEY;
3326         key.offset = (u64)-1;
3327
3328         while (1) {
3329                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3330                 if (ret < 0)
3331                         goto out;
3332
3333                 /*
3334                  * if ret == 0 means we found what we were searching for, which
3335                  * is weird, but possible, so only screw with path if we didn't
3336                  * find the key and see if we have stuff that matches
3337                  */
3338                 if (ret > 0) {
3339                         ret = 0;
3340                         if (path->slots[0] == 0)
3341                                 break;
3342                         path->slots[0]--;
3343                 }
3344
3345                 /* pull out the item */
3346                 leaf = path->nodes[0];
3347                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3348
3349                 /* make sure the item matches what we want */
3350                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3351                         break;
3352                 if (found_key.type != BTRFS_ORPHAN_ITEM_KEY)
3353                         break;
3354
3355                 /* release the path since we're done with it */
3356                 btrfs_release_path(path);
3357
3358                 /*
3359                  * this is where we are basically btrfs_lookup, without the
3360                  * crossing root thing.  we store the inode number in the
3361                  * offset of the orphan item.
3362                  */
3363
3364                 if (found_key.offset == last_objectid) {
3365                         btrfs_err(fs_info,
3366                                   "Error removing orphan entry, stopping orphan cleanup");
3367                         ret = -EINVAL;
3368                         goto out;
3369                 }
3370
3371                 last_objectid = found_key.offset;
3372
3373                 found_key.objectid = found_key.offset;
3374                 found_key.type = BTRFS_INODE_ITEM_KEY;
3375                 found_key.offset = 0;
3376                 inode = btrfs_iget(fs_info->sb, &found_key, root, NULL);
3377                 ret = PTR_ERR_OR_ZERO(inode);
3378                 if (ret && ret != -ENOENT)
3379                         goto out;
3380
3381                 if (ret == -ENOENT && root == fs_info->tree_root) {
3382                         struct btrfs_root *dead_root;
3383                         struct btrfs_fs_info *fs_info = root->fs_info;
3384                         int is_dead_root = 0;
3385
3386                         /*
3387                          * this is an orphan in the tree root. Currently these
3388                          * could come from 2 sources:
3389                          *  a) a snapshot deletion in progress
3390                          *  b) a free space cache inode
3391                          * We need to distinguish those two, as the snapshot
3392                          * orphan must not get deleted.
3393                          * find_dead_roots already ran before us, so if this
3394                          * is a snapshot deletion, we should find the root
3395                          * in the dead_roots list
3396                          */
3397                         spin_lock(&fs_info->trans_lock);
3398                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3399                                             root_list) {
3400                                 if (dead_root->root_key.objectid ==
3401                                     found_key.objectid) {
3402                                         is_dead_root = 1;
3403                                         break;
3404                                 }
3405                         }
3406                         spin_unlock(&fs_info->trans_lock);
3407                         if (is_dead_root) {
3408                                 /* prevent this orphan from being found again */
3409                                 key.offset = found_key.objectid - 1;
3410                                 continue;
3411                         }
3412                 }
3413                 /*
3414                  * Inode is already gone but the orphan item is still there,
3415                  * kill the orphan item.
3416                  */
3417                 if (ret == -ENOENT) {
3418                         trans = btrfs_start_transaction(root, 1);
3419                         if (IS_ERR(trans)) {
3420                                 ret = PTR_ERR(trans);
3421                                 goto out;
3422                         }
3423                         btrfs_debug(fs_info, "auto deleting %Lu",
3424                                     found_key.objectid);
3425                         ret = btrfs_del_orphan_item(trans, root,
3426                                                     found_key.objectid);
3427                         btrfs_end_transaction(trans);
3428                         if (ret)
3429                                 goto out;
3430                         continue;
3431                 }
3432
3433                 /*
3434                  * add this inode to the orphan list so btrfs_orphan_del does
3435                  * the proper thing when we hit it
3436                  */
3437                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3438                         &BTRFS_I(inode)->runtime_flags);
3439                 atomic_inc(&root->orphan_inodes);
3440
3441                 /* if we have links, this was a truncate, lets do that */
3442                 if (inode->i_nlink) {
3443                         if (WARN_ON(!S_ISREG(inode->i_mode))) {
3444                                 iput(inode);
3445                                 continue;
3446                         }
3447                         nr_truncate++;
3448
3449                         /* 1 for the orphan item deletion. */
3450                         trans = btrfs_start_transaction(root, 1);
3451                         if (IS_ERR(trans)) {
3452                                 iput(inode);
3453                                 ret = PTR_ERR(trans);
3454                                 goto out;
3455                         }
3456                         ret = btrfs_orphan_add(trans, inode);
3457                         btrfs_end_transaction(trans);
3458                         if (ret) {
3459                                 iput(inode);
3460                                 goto out;
3461                         }
3462
3463                         ret = btrfs_truncate(inode);
3464                         if (ret)
3465                                 btrfs_orphan_del(NULL, inode);
3466                 } else {
3467                         nr_unlink++;
3468                 }
3469
3470                 /* this will do delete_inode and everything for us */
3471                 iput(inode);
3472                 if (ret)
3473                         goto out;
3474         }
3475         /* release the path since we're done with it */
3476         btrfs_release_path(path);
3477
3478         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3479
3480         if (root->orphan_block_rsv)
3481                 btrfs_block_rsv_release(fs_info, root->orphan_block_rsv,
3482                                         (u64)-1);
3483
3484         if (root->orphan_block_rsv ||
3485             test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
3486                 trans = btrfs_join_transaction(root);
3487                 if (!IS_ERR(trans))
3488                         btrfs_end_transaction(trans);
3489         }
3490
3491         if (nr_unlink)
3492                 btrfs_debug(fs_info, "unlinked %d orphans", nr_unlink);
3493         if (nr_truncate)
3494                 btrfs_debug(fs_info, "truncated %d orphans", nr_truncate);
3495
3496 out:
3497         if (ret)
3498                 btrfs_err(fs_info, "could not do orphan cleanup %d", ret);
3499         btrfs_free_path(path);
3500         return ret;
3501 }
3502
3503 /*
3504  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3505  * don't find any xattrs, we know there can't be any acls.
3506  *
3507  * slot is the slot the inode is in, objectid is the objectid of the inode
3508  */
3509 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3510                                           int slot, u64 objectid,
3511                                           int *first_xattr_slot)
3512 {
3513         u32 nritems = btrfs_header_nritems(leaf);
3514         struct btrfs_key found_key;
3515         static u64 xattr_access = 0;
3516         static u64 xattr_default = 0;
3517         int scanned = 0;
3518
3519         if (!xattr_access) {
3520                 xattr_access = btrfs_name_hash(XATTR_NAME_POSIX_ACL_ACCESS,
3521                                         strlen(XATTR_NAME_POSIX_ACL_ACCESS));
3522                 xattr_default = btrfs_name_hash(XATTR_NAME_POSIX_ACL_DEFAULT,
3523                                         strlen(XATTR_NAME_POSIX_ACL_DEFAULT));
3524         }
3525
3526         slot++;
3527         *first_xattr_slot = -1;
3528         while (slot < nritems) {
3529                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3530
3531                 /* we found a different objectid, there must not be acls */
3532                 if (found_key.objectid != objectid)
3533                         return 0;
3534
3535                 /* we found an xattr, assume we've got an acl */
3536                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3537                         if (*first_xattr_slot == -1)
3538                                 *first_xattr_slot = slot;
3539                         if (found_key.offset == xattr_access ||
3540                             found_key.offset == xattr_default)
3541                                 return 1;
3542                 }
3543
3544                 /*
3545                  * we found a key greater than an xattr key, there can't
3546                  * be any acls later on
3547                  */
3548                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3549                         return 0;
3550
3551                 slot++;
3552                 scanned++;
3553
3554                 /*
3555                  * it goes inode, inode backrefs, xattrs, extents,
3556                  * so if there are a ton of hard links to an inode there can
3557                  * be a lot of backrefs.  Don't waste time searching too hard,
3558                  * this is just an optimization
3559                  */
3560                 if (scanned >= 8)
3561                         break;
3562         }
3563         /* we hit the end of the leaf before we found an xattr or
3564          * something larger than an xattr.  We have to assume the inode
3565          * has acls
3566          */
3567         if (*first_xattr_slot == -1)
3568                 *first_xattr_slot = slot;
3569         return 1;
3570 }
3571
3572 /*
3573  * read an inode from the btree into the in-memory inode
3574  */
3575 static int btrfs_read_locked_inode(struct inode *inode)
3576 {
3577         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3578         struct btrfs_path *path;
3579         struct extent_buffer *leaf;
3580         struct btrfs_inode_item *inode_item;
3581         struct btrfs_root *root = BTRFS_I(inode)->root;
3582         struct btrfs_key location;
3583         unsigned long ptr;
3584         int maybe_acls;
3585         u32 rdev;
3586         int ret;
3587         bool filled = false;
3588         int first_xattr_slot;
3589
3590         ret = btrfs_fill_inode(inode, &rdev);
3591         if (!ret)
3592                 filled = true;
3593
3594         path = btrfs_alloc_path();
3595         if (!path) {
3596                 ret = -ENOMEM;
3597                 goto make_bad;
3598         }
3599
3600         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3601
3602         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3603         if (ret) {
3604                 if (ret > 0)
3605                         ret = -ENOENT;
3606                 goto make_bad;
3607         }
3608
3609         leaf = path->nodes[0];
3610
3611         if (filled)
3612                 goto cache_index;
3613
3614         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3615                                     struct btrfs_inode_item);
3616         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3617         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3618         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3619         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3620         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
3621
3622         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->atime);
3623         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->atime);
3624
3625         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->mtime);
3626         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->mtime);
3627
3628         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->ctime);
3629         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->ctime);
3630
3631         BTRFS_I(inode)->i_otime.tv_sec =
3632                 btrfs_timespec_sec(leaf, &inode_item->otime);
3633         BTRFS_I(inode)->i_otime.tv_nsec =
3634                 btrfs_timespec_nsec(leaf, &inode_item->otime);
3635
3636         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3637         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3638         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3639
3640         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
3641         inode->i_generation = BTRFS_I(inode)->generation;
3642         inode->i_rdev = 0;
3643         rdev = btrfs_inode_rdev(leaf, inode_item);
3644
3645         BTRFS_I(inode)->index_cnt = (u64)-1;
3646         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3647
3648 cache_index:
3649         /*
3650          * If we were modified in the current generation and evicted from memory
3651          * and then re-read we need to do a full sync since we don't have any
3652          * idea about which extents were modified before we were evicted from
3653          * cache.
3654          *
3655          * This is required for both inode re-read from disk and delayed inode
3656          * in delayed_nodes_tree.
3657          */
3658         if (BTRFS_I(inode)->last_trans == fs_info->generation)
3659                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3660                         &BTRFS_I(inode)->runtime_flags);
3661
3662         /*
3663          * We don't persist the id of the transaction where an unlink operation
3664          * against the inode was last made. So here we assume the inode might
3665          * have been evicted, and therefore the exact value of last_unlink_trans
3666          * lost, and set it to last_trans to avoid metadata inconsistencies
3667          * between the inode and its parent if the inode is fsync'ed and the log
3668          * replayed. For example, in the scenario:
3669          *
3670          * touch mydir/foo
3671          * ln mydir/foo mydir/bar
3672          * sync
3673          * unlink mydir/bar
3674          * echo 2 > /proc/sys/vm/drop_caches   # evicts inode
3675          * xfs_io -c fsync mydir/foo
3676          * <power failure>
3677          * mount fs, triggers fsync log replay
3678          *
3679          * We must make sure that when we fsync our inode foo we also log its
3680          * parent inode, otherwise after log replay the parent still has the
3681          * dentry with the "bar" name but our inode foo has a link count of 1
3682          * and doesn't have an inode ref with the name "bar" anymore.
3683          *
3684          * Setting last_unlink_trans to last_trans is a pessimistic approach,
3685          * but it guarantees correctness at the expense of occasional full
3686          * transaction commits on fsync if our inode is a directory, or if our
3687          * inode is not a directory, logging its parent unnecessarily.
3688          */
3689         BTRFS_I(inode)->last_unlink_trans = BTRFS_I(inode)->last_trans;
3690
3691         path->slots[0]++;
3692         if (inode->i_nlink != 1 ||
3693             path->slots[0] >= btrfs_header_nritems(leaf))
3694                 goto cache_acl;
3695
3696         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3697         if (location.objectid != btrfs_ino(BTRFS_I(inode)))
3698                 goto cache_acl;
3699
3700         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3701         if (location.type == BTRFS_INODE_REF_KEY) {
3702                 struct btrfs_inode_ref *ref;
3703
3704                 ref = (struct btrfs_inode_ref *)ptr;
3705                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3706         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3707                 struct btrfs_inode_extref *extref;
3708
3709                 extref = (struct btrfs_inode_extref *)ptr;
3710                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3711                                                                      extref);
3712         }
3713 cache_acl:
3714         /*
3715          * try to precache a NULL acl entry for files that don't have
3716          * any xattrs or acls
3717          */
3718         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3719                         btrfs_ino(BTRFS_I(inode)), &first_xattr_slot);
3720         if (first_xattr_slot != -1) {
3721                 path->slots[0] = first_xattr_slot;
3722                 ret = btrfs_load_inode_props(inode, path);
3723                 if (ret)
3724                         btrfs_err(fs_info,
3725                                   "error loading props for ino %llu (root %llu): %d",
3726                                   btrfs_ino(BTRFS_I(inode)),
3727                                   root->root_key.objectid, ret);
3728         }
3729         btrfs_free_path(path);
3730
3731         if (!maybe_acls)
3732                 cache_no_acl(inode);
3733
3734         switch (inode->i_mode & S_IFMT) {
3735         case S_IFREG:
3736                 inode->i_mapping->a_ops = &btrfs_aops;
3737                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3738                 inode->i_fop = &btrfs_file_operations;
3739                 inode->i_op = &btrfs_file_inode_operations;
3740                 break;
3741         case S_IFDIR:
3742                 inode->i_fop = &btrfs_dir_file_operations;
3743                 inode->i_op = &btrfs_dir_inode_operations;
3744                 break;
3745         case S_IFLNK:
3746                 inode->i_op = &btrfs_symlink_inode_operations;
3747                 inode_nohighmem(inode);
3748                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3749                 break;
3750         default:
3751                 inode->i_op = &btrfs_special_inode_operations;
3752                 init_special_inode(inode, inode->i_mode, rdev);
3753                 break;
3754         }
3755
3756         btrfs_update_iflags(inode);
3757         return 0;
3758
3759 make_bad:
3760         btrfs_free_path(path);
3761         make_bad_inode(inode);
3762         return ret;
3763 }
3764
3765 /*
3766  * given a leaf and an inode, copy the inode fields into the leaf
3767  */
3768 static void fill_inode_item(struct btrfs_trans_handle *trans,
3769                             struct extent_buffer *leaf,
3770                             struct btrfs_inode_item *item,
3771                             struct inode *inode)
3772 {
3773         struct btrfs_map_token token;
3774
3775         btrfs_init_map_token(&token);
3776
3777         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3778         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3779         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3780                                    &token);
3781         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3782         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3783
3784         btrfs_set_token_timespec_sec(leaf, &item->atime,
3785                                      inode->i_atime.tv_sec, &token);
3786         btrfs_set_token_timespec_nsec(leaf, &item->atime,
3787                                       inode->i_atime.tv_nsec, &token);
3788
3789         btrfs_set_token_timespec_sec(leaf, &item->mtime,
3790                                      inode->i_mtime.tv_sec, &token);
3791         btrfs_set_token_timespec_nsec(leaf, &item->mtime,
3792                                       inode->i_mtime.tv_nsec, &token);
3793
3794         btrfs_set_token_timespec_sec(leaf, &item->ctime,
3795                                      inode->i_ctime.tv_sec, &token);
3796         btrfs_set_token_timespec_nsec(leaf, &item->ctime,
3797                                       inode->i_ctime.tv_nsec, &token);
3798
3799         btrfs_set_token_timespec_sec(leaf, &item->otime,
3800                                      BTRFS_I(inode)->i_otime.tv_sec, &token);
3801         btrfs_set_token_timespec_nsec(leaf, &item->otime,
3802                                       BTRFS_I(inode)->i_otime.tv_nsec, &token);
3803
3804         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3805                                      &token);
3806         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3807                                          &token);
3808         btrfs_set_token_inode_sequence(leaf, item, inode->i_version, &token);
3809         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3810         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3811         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3812         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3813 }
3814
3815 /*
3816  * copy everything in the in-memory inode into the btree.
3817  */
3818 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3819                                 struct btrfs_root *root, struct inode *inode)
3820 {
3821         struct btrfs_inode_item *inode_item;
3822         struct btrfs_path *path;
3823         struct extent_buffer *leaf;
3824         int ret;
3825
3826         path = btrfs_alloc_path();
3827         if (!path)
3828                 return -ENOMEM;
3829
3830         path->leave_spinning = 1;
3831         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3832                                  1);
3833         if (ret) {
3834                 if (ret > 0)
3835                         ret = -ENOENT;
3836                 goto failed;
3837         }
3838
3839         leaf = path->nodes[0];
3840         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3841                                     struct btrfs_inode_item);
3842
3843         fill_inode_item(trans, leaf, inode_item, inode);
3844         btrfs_mark_buffer_dirty(leaf);
3845         btrfs_set_inode_last_trans(trans, inode);
3846         ret = 0;
3847 failed:
3848         btrfs_free_path(path);
3849         return ret;
3850 }
3851
3852 /*
3853  * copy everything in the in-memory inode into the btree.
3854  */
3855 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3856                                 struct btrfs_root *root, struct inode *inode)
3857 {
3858         struct btrfs_fs_info *fs_info = root->fs_info;
3859         int ret;
3860
3861         /*
3862          * If the inode is a free space inode, we can deadlock during commit
3863          * if we put it into the delayed code.
3864          *
3865          * The data relocation inode should also be directly updated
3866          * without delay
3867          */
3868         if (!btrfs_is_free_space_inode(inode)
3869             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
3870             && !test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) {
3871                 btrfs_update_root_times(trans, root);
3872
3873                 ret = btrfs_delayed_update_inode(trans, root, inode);
3874                 if (!ret)
3875                         btrfs_set_inode_last_trans(trans, inode);
3876                 return ret;
3877         }
3878
3879         return btrfs_update_inode_item(trans, root, inode);
3880 }
3881
3882 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3883                                          struct btrfs_root *root,
3884                                          struct inode *inode)
3885 {
3886         int ret;
3887
3888         ret = btrfs_update_inode(trans, root, inode);
3889         if (ret == -ENOSPC)
3890                 return btrfs_update_inode_item(trans, root, inode);
3891         return ret;
3892 }
3893
3894 /*
3895  * unlink helper that gets used here in inode.c and in the tree logging
3896  * recovery code.  It remove a link in a directory with a given name, and
3897  * also drops the back refs in the inode to the directory
3898  */
3899 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3900                                 struct btrfs_root *root,
3901                                 struct btrfs_inode *dir,
3902                                 struct btrfs_inode *inode,
3903                                 const char *name, int name_len)
3904 {
3905         struct btrfs_fs_info *fs_info = root->fs_info;
3906         struct btrfs_path *path;
3907         int ret = 0;
3908         struct extent_buffer *leaf;
3909         struct btrfs_dir_item *di;
3910         struct btrfs_key key;
3911         u64 index;
3912         u64 ino = btrfs_ino(inode);
3913         u64 dir_ino = btrfs_ino(dir);
3914
3915         path = btrfs_alloc_path();
3916         if (!path) {
3917                 ret = -ENOMEM;
3918                 goto out;
3919         }
3920
3921         path->leave_spinning = 1;
3922         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3923                                     name, name_len, -1);
3924         if (IS_ERR(di)) {
3925                 ret = PTR_ERR(di);
3926                 goto err;
3927         }
3928         if (!di) {
3929                 ret = -ENOENT;
3930                 goto err;
3931         }
3932         leaf = path->nodes[0];
3933         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3934         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3935         if (ret)
3936                 goto err;
3937         btrfs_release_path(path);
3938
3939         /*
3940          * If we don't have dir index, we have to get it by looking up
3941          * the inode ref, since we get the inode ref, remove it directly,
3942          * it is unnecessary to do delayed deletion.
3943          *
3944          * But if we have dir index, needn't search inode ref to get it.
3945          * Since the inode ref is close to the inode item, it is better
3946          * that we delay to delete it, and just do this deletion when
3947          * we update the inode item.
3948          */
3949         if (inode->dir_index) {
3950                 ret = btrfs_delayed_delete_inode_ref(inode);
3951                 if (!ret) {
3952                         index = inode->dir_index;
3953                         goto skip_backref;
3954                 }
3955         }
3956
3957         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3958                                   dir_ino, &index);
3959         if (ret) {
3960                 btrfs_info(fs_info,
3961                         "failed to delete reference to %.*s, inode %llu parent %llu",
3962                         name_len, name, ino, dir_ino);
3963                 btrfs_abort_transaction(trans, ret);
3964                 goto err;
3965         }
3966 skip_backref:
3967         ret = btrfs_delete_delayed_dir_index(trans, fs_info, dir, index);
3968         if (ret) {
3969                 btrfs_abort_transaction(trans, ret);
3970                 goto err;
3971         }
3972
3973         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len, inode,
3974                         dir_ino);
3975         if (ret != 0 && ret != -ENOENT) {
3976                 btrfs_abort_transaction(trans, ret);
3977                 goto err;
3978         }
3979
3980         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len, dir,
3981                         index);
3982         if (ret == -ENOENT)
3983                 ret = 0;
3984         else if (ret)
3985                 btrfs_abort_transaction(trans, ret);
3986 err:
3987         btrfs_free_path(path);
3988         if (ret)
3989                 goto out;
3990
3991         btrfs_i_size_write(&dir->vfs_inode,
3992                         dir->vfs_inode.i_size - name_len * 2);
3993         inode_inc_iversion(&inode->vfs_inode);
3994         inode_inc_iversion(&dir->vfs_inode);
3995         inode->vfs_inode.i_ctime = dir->vfs_inode.i_mtime =
3996                 dir->vfs_inode.i_ctime = current_time(&inode->vfs_inode);
3997         ret = btrfs_update_inode(trans, root, &dir->vfs_inode);
3998 out:
3999         return ret;
4000 }
4001
4002 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
4003                        struct btrfs_root *root,
4004                        struct btrfs_inode *dir, struct btrfs_inode *inode,
4005                        const char *name, int name_len)
4006 {
4007         int ret;
4008         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
4009         if (!ret) {
4010                 drop_nlink(&inode->vfs_inode);
4011                 ret = btrfs_update_inode(trans, root, &inode->vfs_inode);
4012         }
4013         return ret;
4014 }
4015
4016 /*
4017  * helper to start transaction for unlink and rmdir.
4018  *
4019  * unlink and rmdir are special in btrfs, they do not always free space, so
4020  * if we cannot make our reservations the normal way try and see if there is
4021  * plenty of slack room in the global reserve to migrate, otherwise we cannot
4022  * allow the unlink to occur.
4023  */
4024 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
4025 {
4026         struct btrfs_root *root = BTRFS_I(dir)->root;
4027
4028         /*
4029          * 1 for the possible orphan item
4030          * 1 for the dir item
4031          * 1 for the dir index
4032          * 1 for the inode ref
4033          * 1 for the inode
4034          */
4035         return btrfs_start_transaction_fallback_global_rsv(root, 5, 5);
4036 }
4037
4038 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
4039 {
4040         struct btrfs_root *root = BTRFS_I(dir)->root;
4041         struct btrfs_trans_handle *trans;
4042         struct inode *inode = d_inode(dentry);
4043         int ret;
4044
4045         trans = __unlink_start_trans(dir);
4046         if (IS_ERR(trans))
4047                 return PTR_ERR(trans);
4048
4049         btrfs_record_unlink_dir(trans, BTRFS_I(dir), BTRFS_I(d_inode(dentry)),
4050                         0);
4051
4052         ret = btrfs_unlink_inode(trans, root, BTRFS_I(dir),
4053                         BTRFS_I(d_inode(dentry)), dentry->d_name.name,
4054                         dentry->d_name.len);
4055         if (ret)
4056                 goto out;
4057
4058         if (inode->i_nlink == 0) {
4059                 ret = btrfs_orphan_add(trans, inode);
4060                 if (ret)
4061                         goto out;
4062         }
4063
4064 out:
4065         btrfs_end_transaction(trans);
4066         btrfs_btree_balance_dirty(root->fs_info);
4067         return ret;
4068 }
4069
4070 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
4071                         struct btrfs_root *root,
4072                         struct inode *dir, u64 objectid,
4073                         const char *name, int name_len)
4074 {
4075         struct btrfs_fs_info *fs_info = root->fs_info;
4076         struct btrfs_path *path;
4077         struct extent_buffer *leaf;
4078         struct btrfs_dir_item *di;
4079         struct btrfs_key key;
4080         u64 index;
4081         int ret;
4082         u64 dir_ino = btrfs_ino(BTRFS_I(dir));
4083
4084         path = btrfs_alloc_path();
4085         if (!path)
4086                 return -ENOMEM;
4087
4088         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
4089                                    name, name_len, -1);
4090         if (IS_ERR_OR_NULL(di)) {
4091                 if (!di)
4092                         ret = -ENOENT;
4093                 else
4094                         ret = PTR_ERR(di);
4095                 goto out;
4096         }
4097
4098         leaf = path->nodes[0];
4099         btrfs_dir_item_key_to_cpu(leaf, di, &key);
4100         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
4101         ret = btrfs_delete_one_dir_name(trans, root, path, di);
4102         if (ret) {
4103                 btrfs_abort_transaction(trans, ret);
4104                 goto out;
4105         }
4106         btrfs_release_path(path);
4107
4108         ret = btrfs_del_root_ref(trans, fs_info, objectid,
4109                                  root->root_key.objectid, dir_ino,
4110                                  &index, name, name_len);
4111         if (ret < 0) {
4112                 if (ret != -ENOENT) {
4113                         btrfs_abort_transaction(trans, ret);
4114                         goto out;
4115                 }
4116                 di = btrfs_search_dir_index_item(root, path, dir_ino,
4117                                                  name, name_len);
4118                 if (IS_ERR_OR_NULL(di)) {
4119                         if (!di)
4120                                 ret = -ENOENT;
4121                         else
4122                                 ret = PTR_ERR(di);
4123                         btrfs_abort_transaction(trans, ret);
4124                         goto out;
4125                 }
4126
4127                 leaf = path->nodes[0];
4128                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4129                 btrfs_release_path(path);
4130                 index = key.offset;
4131         }
4132         btrfs_release_path(path);
4133
4134         ret = btrfs_delete_delayed_dir_index(trans, fs_info, BTRFS_I(dir), index);
4135         if (ret) {
4136                 btrfs_abort_transaction(trans, ret);
4137                 goto out;
4138         }
4139
4140         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
4141         inode_inc_iversion(dir);
4142         dir->i_mtime = dir->i_ctime = current_time(dir);
4143         ret = btrfs_update_inode_fallback(trans, root, dir);
4144         if (ret)
4145                 btrfs_abort_transaction(trans, ret);
4146 out:
4147         btrfs_free_path(path);
4148         return ret;
4149 }
4150
4151 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
4152 {
4153         struct inode *inode = d_inode(dentry);
4154         int err = 0;
4155         struct btrfs_root *root = BTRFS_I(dir)->root;
4156         struct btrfs_trans_handle *trans;
4157         u64 last_unlink_trans;
4158
4159         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
4160                 return -ENOTEMPTY;
4161         if (btrfs_ino(BTRFS_I(inode)) == BTRFS_FIRST_FREE_OBJECTID)
4162                 return -EPERM;
4163
4164         trans = __unlink_start_trans(dir);
4165         if (IS_ERR(trans))
4166                 return PTR_ERR(trans);
4167
4168         if (unlikely(btrfs_ino(BTRFS_I(inode)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
4169                 err = btrfs_unlink_subvol(trans, root, dir,
4170                                           BTRFS_I(inode)->location.objectid,
4171                                           dentry->d_name.name,
4172                                           dentry->d_name.len);
4173                 goto out;
4174         }
4175
4176         err = btrfs_orphan_add(trans, inode);
4177         if (err)
4178                 goto out;
4179
4180         last_unlink_trans = BTRFS_I(inode)->last_unlink_trans;
4181
4182         /* now the directory is empty */
4183         err = btrfs_unlink_inode(trans, root, BTRFS_I(dir),
4184                         BTRFS_I(d_inode(dentry)), dentry->d_name.name,
4185                         dentry->d_name.len);
4186         if (!err) {
4187                 btrfs_i_size_write(inode, 0);
4188                 /*
4189                  * Propagate the last_unlink_trans value of the deleted dir to
4190                  * its parent directory. This is to prevent an unrecoverable
4191                  * log tree in the case we do something like this:
4192                  * 1) create dir foo
4193                  * 2) create snapshot under dir foo
4194                  * 3) delete the snapshot
4195                  * 4) rmdir foo
4196                  * 5) mkdir foo
4197                  * 6) fsync foo or some file inside foo
4198                  */
4199                 if (last_unlink_trans >= trans->transid)
4200                         BTRFS_I(dir)->last_unlink_trans = last_unlink_trans;
4201         }
4202 out:
4203         btrfs_end_transaction(trans);
4204         btrfs_btree_balance_dirty(root->fs_info);
4205
4206         return err;
4207 }
4208
4209 static int truncate_space_check(struct btrfs_trans_handle *trans,
4210                                 struct btrfs_root *root,
4211                                 u64 bytes_deleted)
4212 {
4213         struct btrfs_fs_info *fs_info = root->fs_info;
4214         int ret;
4215
4216         /*
4217          * This is only used to apply pressure to the enospc system, we don't
4218          * intend to use this reservation at all.
4219          */
4220         bytes_deleted = btrfs_csum_bytes_to_leaves(fs_info, bytes_deleted);
4221         bytes_deleted *= fs_info->nodesize;
4222         ret = btrfs_block_rsv_add(root, &fs_info->trans_block_rsv,
4223                                   bytes_deleted, BTRFS_RESERVE_NO_FLUSH);
4224         if (!ret) {
4225                 trace_btrfs_space_reservation(fs_info, "transaction",
4226                                               trans->transid,
4227                                               bytes_deleted, 1);
4228                 trans->bytes_reserved += bytes_deleted;
4229         }
4230         return ret;
4231
4232 }
4233
4234 static int truncate_inline_extent(struct inode *inode,
4235                                   struct btrfs_path *path,
4236                                   struct btrfs_key *found_key,
4237                                   const u64 item_end,
4238                                   const u64 new_size)
4239 {
4240         struct extent_buffer *leaf = path->nodes[0];
4241         int slot = path->slots[0];
4242         struct btrfs_file_extent_item *fi;
4243         u32 size = (u32)(new_size - found_key->offset);
4244         struct btrfs_root *root = BTRFS_I(inode)->root;
4245
4246         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
4247
4248         if (btrfs_file_extent_compression(leaf, fi) != BTRFS_COMPRESS_NONE) {
4249                 loff_t offset = new_size;
4250                 loff_t page_end = ALIGN(offset, PAGE_SIZE);
4251
4252                 /*
4253                  * Zero out the remaining of the last page of our inline extent,
4254                  * instead of directly truncating our inline extent here - that
4255                  * would be much more complex (decompressing all the data, then
4256                  * compressing the truncated data, which might be bigger than
4257                  * the size of the inline extent, resize the extent, etc).
4258                  * We release the path because to get the page we might need to
4259                  * read the extent item from disk (data not in the page cache).
4260                  */
4261                 btrfs_release_path(path);
4262                 return btrfs_truncate_block(inode, offset, page_end - offset,
4263                                         0);
4264         }
4265
4266         btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4267         size = btrfs_file_extent_calc_inline_size(size);
4268         btrfs_truncate_item(root->fs_info, path, size, 1);
4269
4270         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4271                 inode_sub_bytes(inode, item_end + 1 - new_size);
4272
4273         return 0;
4274 }
4275
4276 /*
4277  * this can truncate away extent items, csum items and directory items.
4278  * It starts at a high offset and removes keys until it can't find
4279  * any higher than new_size
4280  *
4281  * csum items that cross the new i_size are truncated to the new size
4282  * as well.
4283  *
4284  * min_type is the minimum key type to truncate down to.  If set to 0, this
4285  * will kill all the items on this inode, including the INODE_ITEM_KEY.
4286  */
4287 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
4288                                struct btrfs_root *root,
4289                                struct inode *inode,
4290                                u64 new_size, u32 min_type)
4291 {
4292         struct btrfs_fs_info *fs_info = root->fs_info;
4293         struct btrfs_path *path;
4294         struct extent_buffer *leaf;
4295         struct btrfs_file_extent_item *fi;
4296         struct btrfs_key key;
4297         struct btrfs_key found_key;
4298         u64 extent_start = 0;
4299         u64 extent_num_bytes = 0;
4300         u64 extent_offset = 0;
4301         u64 item_end = 0;
4302         u64 last_size = new_size;
4303         u32 found_type = (u8)-1;
4304         int found_extent;
4305         int del_item;
4306         int pending_del_nr = 0;
4307         int pending_del_slot = 0;
4308         int extent_type = -1;
4309         int ret;
4310         int err = 0;
4311         u64 ino = btrfs_ino(BTRFS_I(inode));
4312         u64 bytes_deleted = 0;
4313         bool be_nice = 0;
4314         bool should_throttle = 0;
4315         bool should_end = 0;
4316
4317         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
4318
4319         /*
4320          * for non-free space inodes and ref cows, we want to back off from
4321          * time to time
4322          */
4323         if (!btrfs_is_free_space_inode(inode) &&
4324             test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4325                 be_nice = 1;
4326
4327         path = btrfs_alloc_path();
4328         if (!path)
4329                 return -ENOMEM;
4330         path->reada = READA_BACK;
4331
4332         /*
4333          * We want to drop from the next block forward in case this new size is
4334          * not block aligned since we will be keeping the last block of the
4335          * extent just the way it is.
4336          */
4337         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4338             root == fs_info->tree_root)
4339                 btrfs_drop_extent_cache(inode, ALIGN(new_size,
4340                                         fs_info->sectorsize),
4341                                         (u64)-1, 0);
4342
4343         /*
4344          * This function is also used to drop the items in the log tree before
4345          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4346          * it is used to drop the loged items. So we shouldn't kill the delayed
4347          * items.
4348          */
4349         if (min_type == 0 && root == BTRFS_I(inode)->root)
4350                 btrfs_kill_delayed_inode_items(BTRFS_I(inode));
4351
4352         key.objectid = ino;
4353         key.offset = (u64)-1;
4354         key.type = (u8)-1;
4355
4356 search_again:
4357         /*
4358          * with a 16K leaf size and 128MB extents, you can actually queue
4359          * up a huge file in a single leaf.  Most of the time that
4360          * bytes_deleted is > 0, it will be huge by the time we get here
4361          */
4362         if (be_nice && bytes_deleted > SZ_32M) {
4363                 if (btrfs_should_end_transaction(trans)) {
4364                         err = -EAGAIN;
4365                         goto error;
4366                 }
4367         }
4368
4369
4370         path->leave_spinning = 1;
4371         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4372         if (ret < 0) {
4373                 err = ret;
4374                 goto out;
4375         }
4376
4377         if (ret > 0) {
4378                 /* there are no items in the tree for us to truncate, we're
4379                  * done
4380                  */
4381                 if (path->slots[0] == 0)
4382                         goto out;
4383                 path->slots[0]--;
4384         }
4385
4386         while (1) {
4387                 fi = NULL;
4388                 leaf = path->nodes[0];
4389                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4390                 found_type = found_key.type;
4391
4392                 if (found_key.objectid != ino)
4393                         break;
4394
4395                 if (found_type < min_type)
4396                         break;
4397
4398                 item_end = found_key.offset;
4399                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4400                         fi = btrfs_item_ptr(leaf, path->slots[0],
4401                                             struct btrfs_file_extent_item);
4402                         extent_type = btrfs_file_extent_type(leaf, fi);
4403                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4404                                 item_end +=
4405                                     btrfs_file_extent_num_bytes(leaf, fi);
4406                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4407                                 item_end += btrfs_file_extent_inline_len(leaf,
4408                                                          path->slots[0], fi);
4409                         }
4410                         item_end--;
4411                 }
4412                 if (found_type > min_type) {
4413                         del_item = 1;
4414                 } else {
4415                         if (item_end < new_size) {
4416                                 /*
4417                                  * With NO_HOLES mode, for the following mapping
4418                                  *
4419                                  * [0-4k][hole][8k-12k]
4420                                  *
4421                                  * if truncating isize down to 6k, it ends up
4422                                  * isize being 8k.
4423                                  */
4424                                 if (btrfs_fs_incompat(root->fs_info, NO_HOLES))
4425                                         last_size = new_size;
4426                                 break;
4427                         }
4428                         if (found_key.offset >= new_size)
4429                                 del_item = 1;
4430                         else
4431                                 del_item = 0;
4432                 }
4433                 found_extent = 0;
4434                 /* FIXME, shrink the extent if the ref count is only 1 */
4435                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4436                         goto delete;
4437
4438                 if (del_item)
4439                         last_size = found_key.offset;
4440                 else
4441                         last_size = new_size;
4442
4443                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4444                         u64 num_dec;
4445                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4446                         if (!del_item) {
4447                                 u64 orig_num_bytes =
4448                                         btrfs_file_extent_num_bytes(leaf, fi);
4449                                 extent_num_bytes = ALIGN(new_size -
4450                                                 found_key.offset,
4451                                                 fs_info->sectorsize);
4452                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4453                                                          extent_num_bytes);
4454                                 num_dec = (orig_num_bytes -
4455                                            extent_num_bytes);
4456                                 if (test_bit(BTRFS_ROOT_REF_COWS,
4457                                              &root->state) &&
4458                                     extent_start != 0)
4459                                         inode_sub_bytes(inode, num_dec);
4460                                 btrfs_mark_buffer_dirty(leaf);
4461                         } else {
4462                                 extent_num_bytes =
4463                                         btrfs_file_extent_disk_num_bytes(leaf,
4464                                                                          fi);
4465                                 extent_offset = found_key.offset -
4466                                         btrfs_file_extent_offset(leaf, fi);
4467
4468                                 /* FIXME blocksize != 4096 */
4469                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4470                                 if (extent_start != 0) {
4471                                         found_extent = 1;
4472                                         if (test_bit(BTRFS_ROOT_REF_COWS,
4473                                                      &root->state))
4474                                                 inode_sub_bytes(inode, num_dec);
4475                                 }
4476                         }
4477                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4478                         /*
4479                          * we can't truncate inline items that have had
4480                          * special encodings
4481                          */
4482                         if (!del_item &&
4483                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4484                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
4485
4486                                 /*
4487                                  * Need to release path in order to truncate a
4488                                  * compressed extent. So delete any accumulated
4489                                  * extent items so far.
4490                                  */
4491                                 if (btrfs_file_extent_compression(leaf, fi) !=
4492                                     BTRFS_COMPRESS_NONE && pending_del_nr) {
4493                                         err = btrfs_del_items(trans, root, path,
4494                                                               pending_del_slot,
4495                                                               pending_del_nr);
4496                                         if (err) {
4497                                                 btrfs_abort_transaction(trans,
4498                                                                         err);
4499                                                 goto error;
4500                                         }
4501                                         pending_del_nr = 0;
4502                                 }
4503
4504                                 err = truncate_inline_extent(inode, path,
4505                                                              &found_key,
4506                                                              item_end,
4507                                                              new_size);
4508                                 if (err) {
4509                                         btrfs_abort_transaction(trans, err);
4510                                         goto error;
4511                                 }
4512                         } else if (test_bit(BTRFS_ROOT_REF_COWS,
4513                                             &root->state)) {
4514                                 inode_sub_bytes(inode, item_end + 1 - new_size);
4515                         }
4516                 }
4517 delete:
4518                 if (del_item) {
4519                         if (!pending_del_nr) {
4520                                 /* no pending yet, add ourselves */
4521                                 pending_del_slot = path->slots[0];
4522                                 pending_del_nr = 1;
4523                         } else if (pending_del_nr &&
4524                                    path->slots[0] + 1 == pending_del_slot) {
4525                                 /* hop on the pending chunk */
4526                                 pending_del_nr++;
4527                                 pending_del_slot = path->slots[0];
4528                         } else {
4529                                 BUG();
4530                         }
4531                 } else {
4532                         break;
4533                 }
4534                 should_throttle = 0;
4535
4536                 if (found_extent &&
4537                     (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4538                      root == fs_info->tree_root)) {
4539                         btrfs_set_path_blocking(path);
4540                         bytes_deleted += extent_num_bytes;
4541                         ret = btrfs_free_extent(trans, fs_info, extent_start,
4542                                                 extent_num_bytes, 0,
4543                                                 btrfs_header_owner(leaf),
4544                                                 ino, extent_offset);
4545                         BUG_ON(ret);
4546                         if (btrfs_should_throttle_delayed_refs(trans, fs_info))
4547                                 btrfs_async_run_delayed_refs(fs_info,
4548                                         trans->delayed_ref_updates * 2,
4549                                         trans->transid, 0);
4550                         if (be_nice) {
4551                                 if (truncate_space_check(trans, root,
4552                                                          extent_num_bytes)) {
4553                                         should_end = 1;
4554                                 }
4555                                 if (btrfs_should_throttle_delayed_refs(trans,
4556                                                                        fs_info))
4557                                         should_throttle = 1;
4558                         }
4559                 }
4560
4561                 if (found_type == BTRFS_INODE_ITEM_KEY)
4562                         break;
4563
4564                 if (path->slots[0] == 0 ||
4565                     path->slots[0] != pending_del_slot ||
4566                     should_throttle || should_end) {
4567                         if (pending_del_nr) {
4568                                 ret = btrfs_del_items(trans, root, path,
4569                                                 pending_del_slot,
4570                                                 pending_del_nr);
4571                                 if (ret) {
4572                                         btrfs_abort_transaction(trans, ret);
4573                                         goto error;
4574                                 }
4575                                 pending_del_nr = 0;
4576                         }
4577                         btrfs_release_path(path);
4578                         if (should_throttle) {
4579                                 unsigned long updates = trans->delayed_ref_updates;
4580                                 if (updates) {
4581                                         trans->delayed_ref_updates = 0;
4582                                         ret = btrfs_run_delayed_refs(trans,
4583                                                                    fs_info,
4584                                                                    updates * 2);
4585                                         if (ret && !err)
4586                                                 err = ret;
4587                                 }
4588                         }
4589                         /*
4590                          * if we failed to refill our space rsv, bail out
4591                          * and let the transaction restart
4592                          */
4593                         if (should_end) {
4594                                 err = -EAGAIN;
4595                                 goto error;
4596                         }
4597                         goto search_again;
4598                 } else {
4599                         path->slots[0]--;
4600                 }
4601         }
4602 out:
4603         if (pending_del_nr) {
4604                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
4605                                       pending_del_nr);
4606                 if (ret)
4607                         btrfs_abort_transaction(trans, ret);
4608         }
4609 error:
4610         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
4611                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4612
4613         btrfs_free_path(path);
4614
4615         if (err == 0) {
4616                 /* only inline file may have last_size != new_size */
4617                 if (new_size >= fs_info->sectorsize ||
4618                     new_size > fs_info->max_inline)
4619                         ASSERT(last_size == new_size);
4620         }
4621
4622         if (be_nice && bytes_deleted > SZ_32M) {
4623                 unsigned long updates = trans->delayed_ref_updates;
4624                 if (updates) {
4625                         trans->delayed_ref_updates = 0;
4626                         ret = btrfs_run_delayed_refs(trans, fs_info,
4627                                                      updates * 2);
4628                         if (ret && !err)
4629                                 err = ret;
4630                 }
4631         }
4632         return err;
4633 }
4634
4635 /*
4636  * btrfs_truncate_block - read, zero a chunk and write a block
4637  * @inode - inode that we're zeroing
4638  * @from - the offset to start zeroing
4639  * @len - the length to zero, 0 to zero the entire range respective to the
4640  *      offset
4641  * @front - zero up to the offset instead of from the offset on
4642  *
4643  * This will find the block for the "from" offset and cow the block and zero the
4644  * part we want to zero.  This is used with truncate and hole punching.
4645  */
4646 int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len,
4647                         int front)
4648 {
4649         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4650         struct address_space *mapping = inode->i_mapping;
4651         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4652         struct btrfs_ordered_extent *ordered;
4653         struct extent_state *cached_state = NULL;
4654         char *kaddr;
4655         u32 blocksize = fs_info->sectorsize;
4656         pgoff_t index = from >> PAGE_SHIFT;
4657         unsigned offset = from & (blocksize - 1);
4658         struct page *page;
4659         gfp_t mask = btrfs_alloc_write_mask(mapping);
4660         int ret = 0;
4661         u64 block_start;
4662         u64 block_end;
4663
4664         if ((offset & (blocksize - 1)) == 0 &&
4665             (!len || ((len & (blocksize - 1)) == 0)))
4666                 goto out;
4667
4668         ret = btrfs_delalloc_reserve_space(inode,
4669                         round_down(from, blocksize), blocksize);
4670         if (ret)
4671                 goto out;
4672
4673 again:
4674         page = find_or_create_page(mapping, index, mask);
4675         if (!page) {
4676                 btrfs_delalloc_release_space(inode,
4677                                 round_down(from, blocksize),
4678                                 blocksize);
4679                 ret = -ENOMEM;
4680                 goto out;
4681         }
4682
4683         block_start = round_down(from, blocksize);
4684         block_end = block_start + blocksize - 1;
4685
4686         if (!PageUptodate(page)) {
4687                 ret = btrfs_readpage(NULL, page);
4688                 lock_page(page);
4689                 if (page->mapping != mapping) {
4690                         unlock_page(page);
4691                         put_page(page);
4692                         goto again;
4693                 }
4694                 if (!PageUptodate(page)) {
4695                         ret = -EIO;
4696                         goto out_unlock;
4697                 }
4698         }
4699         wait_on_page_writeback(page);
4700
4701         lock_extent_bits(io_tree, block_start, block_end, &cached_state);
4702         set_page_extent_mapped(page);
4703
4704         ordered = btrfs_lookup_ordered_extent(inode, block_start);
4705         if (ordered) {
4706                 unlock_extent_cached(io_tree, block_start, block_end,
4707                                      &cached_state, GFP_NOFS);
4708                 unlock_page(page);
4709                 put_page(page);
4710                 btrfs_start_ordered_extent(inode, ordered, 1);
4711                 btrfs_put_ordered_extent(ordered);
4712                 goto again;
4713         }
4714
4715         clear_extent_bit(&BTRFS_I(inode)->io_tree, block_start, block_end,
4716                           EXTENT_DIRTY | EXTENT_DELALLOC |
4717                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4718                           0, 0, &cached_state, GFP_NOFS);
4719
4720         ret = btrfs_set_extent_delalloc(inode, block_start, block_end,
4721                                         &cached_state, 0);
4722         if (ret) {
4723                 unlock_extent_cached(io_tree, block_start, block_end,
4724                                      &cached_state, GFP_NOFS);
4725                 goto out_unlock;
4726         }
4727
4728         if (offset != blocksize) {
4729                 if (!len)
4730                         len = blocksize - offset;
4731                 kaddr = kmap(page);
4732                 if (front)
4733                         memset(kaddr + (block_start - page_offset(page)),
4734                                 0, offset);
4735                 else
4736                         memset(kaddr + (block_start - page_offset(page)) +  offset,
4737                                 0, len);
4738                 flush_dcache_page(page);
4739                 kunmap(page);
4740         }
4741         ClearPageChecked(page);
4742         set_page_dirty(page);
4743         unlock_extent_cached(io_tree, block_start, block_end, &cached_state,
4744                              GFP_NOFS);
4745
4746 out_unlock:
4747         if (ret)
4748                 btrfs_delalloc_release_space(inode, block_start,
4749                                              blocksize);
4750         unlock_page(page);
4751         put_page(page);
4752 out:
4753         return ret;
4754 }
4755
4756 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4757                              u64 offset, u64 len)
4758 {
4759         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4760         struct btrfs_trans_handle *trans;
4761         int ret;
4762
4763         /*
4764          * Still need to make sure the inode looks like it's been updated so
4765          * that any holes get logged if we fsync.
4766          */
4767         if (btrfs_fs_incompat(fs_info, NO_HOLES)) {
4768                 BTRFS_I(inode)->last_trans = fs_info->generation;
4769                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4770                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4771                 return 0;
4772         }
4773
4774         /*
4775          * 1 - for the one we're dropping
4776          * 1 - for the one we're adding
4777          * 1 - for updating the inode.
4778          */
4779         trans = btrfs_start_transaction(root, 3);
4780         if (IS_ERR(trans))
4781                 return PTR_ERR(trans);
4782
4783         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4784         if (ret) {
4785                 btrfs_abort_transaction(trans, ret);
4786                 btrfs_end_transaction(trans);
4787                 return ret;
4788         }
4789
4790         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(BTRFS_I(inode)),
4791                         offset, 0, 0, len, 0, len, 0, 0, 0);
4792         if (ret)
4793                 btrfs_abort_transaction(trans, ret);
4794         else
4795                 btrfs_update_inode(trans, root, inode);
4796         btrfs_end_transaction(trans);
4797         return ret;
4798 }
4799
4800 /*
4801  * This function puts in dummy file extents for the area we're creating a hole
4802  * for.  So if we are truncating this file to a larger size we need to insert
4803  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4804  * the range between oldsize and size
4805  */
4806 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4807 {
4808         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4809         struct btrfs_root *root = BTRFS_I(inode)->root;
4810         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4811         struct extent_map *em = NULL;
4812         struct extent_state *cached_state = NULL;
4813         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4814         u64 hole_start = ALIGN(oldsize, fs_info->sectorsize);
4815         u64 block_end = ALIGN(size, fs_info->sectorsize);
4816         u64 last_byte;
4817         u64 cur_offset;
4818         u64 hole_size;
4819         int err = 0;
4820
4821         /*
4822          * If our size started in the middle of a block we need to zero out the
4823          * rest of the block before we expand the i_size, otherwise we could
4824          * expose stale data.
4825          */
4826         err = btrfs_truncate_block(inode, oldsize, 0, 0);
4827         if (err)
4828                 return err;
4829
4830         if (size <= hole_start)
4831                 return 0;
4832
4833         while (1) {
4834                 struct btrfs_ordered_extent *ordered;
4835
4836                 lock_extent_bits(io_tree, hole_start, block_end - 1,
4837                                  &cached_state);
4838                 ordered = btrfs_lookup_ordered_range(inode, hole_start,
4839                                                      block_end - hole_start);
4840                 if (!ordered)
4841                         break;
4842                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
4843                                      &cached_state, GFP_NOFS);
4844                 btrfs_start_ordered_extent(inode, ordered, 1);
4845                 btrfs_put_ordered_extent(ordered);
4846         }
4847
4848         cur_offset = hole_start;
4849         while (1) {
4850                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
4851                                 block_end - cur_offset, 0);
4852                 if (IS_ERR(em)) {
4853                         err = PTR_ERR(em);
4854                         em = NULL;
4855                         break;
4856                 }
4857                 last_byte = min(extent_map_end(em), block_end);
4858                 last_byte = ALIGN(last_byte, fs_info->sectorsize);
4859                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4860                         struct extent_map *hole_em;
4861                         hole_size = last_byte - cur_offset;
4862
4863                         err = maybe_insert_hole(root, inode, cur_offset,
4864                                                 hole_size);
4865                         if (err)
4866                                 break;
4867                         btrfs_drop_extent_cache(inode, cur_offset,
4868                                                 cur_offset + hole_size - 1, 0);
4869                         hole_em = alloc_extent_map();
4870                         if (!hole_em) {
4871                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4872                                         &BTRFS_I(inode)->runtime_flags);
4873                                 goto next;
4874                         }
4875                         hole_em->start = cur_offset;
4876                         hole_em->len = hole_size;
4877                         hole_em->orig_start = cur_offset;
4878
4879                         hole_em->block_start = EXTENT_MAP_HOLE;
4880                         hole_em->block_len = 0;
4881                         hole_em->orig_block_len = 0;
4882                         hole_em->ram_bytes = hole_size;
4883                         hole_em->bdev = fs_info->fs_devices->latest_bdev;
4884                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4885                         hole_em->generation = fs_info->generation;
4886
4887                         while (1) {
4888                                 write_lock(&em_tree->lock);
4889                                 err = add_extent_mapping(em_tree, hole_em, 1);
4890                                 write_unlock(&em_tree->lock);
4891                                 if (err != -EEXIST)
4892                                         break;
4893                                 btrfs_drop_extent_cache(inode, cur_offset,
4894                                                         cur_offset +
4895                                                         hole_size - 1, 0);
4896                         }
4897                         free_extent_map(hole_em);
4898                 }
4899 next:
4900                 free_extent_map(em);
4901                 em = NULL;
4902                 cur_offset = last_byte;
4903                 if (cur_offset >= block_end)
4904                         break;
4905         }
4906         free_extent_map(em);
4907         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
4908                              GFP_NOFS);
4909         return err;
4910 }
4911
4912 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4913 {
4914         struct btrfs_root *root = BTRFS_I(inode)->root;
4915         struct btrfs_trans_handle *trans;
4916         loff_t oldsize = i_size_read(inode);
4917         loff_t newsize = attr->ia_size;
4918         int mask = attr->ia_valid;
4919         int ret;
4920
4921         /*
4922          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4923          * special case where we need to update the times despite not having
4924          * these flags set.  For all other operations the VFS set these flags
4925          * explicitly if it wants a timestamp update.
4926          */
4927         if (newsize != oldsize) {
4928                 inode_inc_iversion(inode);
4929                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
4930                         inode->i_ctime = inode->i_mtime =
4931                                 current_time(inode);
4932         }
4933
4934         if (newsize > oldsize) {
4935                 /*
4936                  * Don't do an expanding truncate while snapshoting is ongoing.
4937                  * This is to ensure the snapshot captures a fully consistent
4938                  * state of this file - if the snapshot captures this expanding
4939                  * truncation, it must capture all writes that happened before
4940                  * this truncation.
4941                  */
4942                 btrfs_wait_for_snapshot_creation(root);
4943                 ret = btrfs_cont_expand(inode, oldsize, newsize);
4944                 if (ret) {
4945                         btrfs_end_write_no_snapshoting(root);
4946                         return ret;
4947                 }
4948
4949                 trans = btrfs_start_transaction(root, 1);
4950                 if (IS_ERR(trans)) {
4951                         btrfs_end_write_no_snapshoting(root);
4952                         return PTR_ERR(trans);
4953                 }
4954
4955                 i_size_write(inode, newsize);
4956                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
4957                 pagecache_isize_extended(inode, oldsize, newsize);
4958                 ret = btrfs_update_inode(trans, root, inode);
4959                 btrfs_end_write_no_snapshoting(root);
4960                 btrfs_end_transaction(trans);
4961         } else {
4962
4963                 /*
4964                  * We're truncating a file that used to have good data down to
4965                  * zero. Make sure it gets into the ordered flush list so that
4966                  * any new writes get down to disk quickly.
4967                  */
4968                 if (newsize == 0)
4969                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
4970                                 &BTRFS_I(inode)->runtime_flags);
4971
4972                 /*
4973                  * 1 for the orphan item we're going to add
4974                  * 1 for the orphan item deletion.
4975                  */
4976                 trans = btrfs_start_transaction(root, 2);
4977                 if (IS_ERR(trans))
4978                         return PTR_ERR(trans);
4979
4980                 /*
4981                  * We need to do this in case we fail at _any_ point during the
4982                  * actual truncate.  Once we do the truncate_setsize we could
4983                  * invalidate pages which forces any outstanding ordered io to
4984                  * be instantly completed which will give us extents that need
4985                  * to be truncated.  If we fail to get an orphan inode down we
4986                  * could have left over extents that were never meant to live,
4987                  * so we need to guarantee from this point on that everything
4988                  * will be consistent.
4989                  */
4990                 ret = btrfs_orphan_add(trans, inode);
4991                 btrfs_end_transaction(trans);
4992                 if (ret)
4993                         return ret;
4994
4995                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
4996                 truncate_setsize(inode, newsize);
4997
4998                 /* Disable nonlocked read DIO to avoid the end less truncate */
4999                 btrfs_inode_block_unlocked_dio(inode);
5000                 inode_dio_wait(inode);
5001                 btrfs_inode_resume_unlocked_dio(inode);
5002
5003                 ret = btrfs_truncate(inode);
5004                 if (ret && inode->i_nlink) {
5005                         int err;
5006
5007                         /* To get a stable disk_i_size */
5008                         err = btrfs_wait_ordered_range(inode, 0, (u64)-1);
5009                         if (err) {
5010                                 btrfs_orphan_del(NULL, inode);
5011                                 return err;
5012                         }
5013
5014                         /*
5015                          * failed to truncate, disk_i_size is only adjusted down
5016                          * as we remove extents, so it should represent the true
5017                          * size of the inode, so reset the in memory size and
5018                          * delete our orphan entry.
5019                          */
5020                         trans = btrfs_join_transaction(root);
5021                         if (IS_ERR(trans)) {
5022                                 btrfs_orphan_del(NULL, inode);
5023                                 return ret;
5024                         }
5025                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
5026                         err = btrfs_orphan_del(trans, inode);
5027                         if (err)
5028                                 btrfs_abort_transaction(trans, err);
5029                         btrfs_end_transaction(trans);
5030                 }
5031         }
5032
5033         return ret;
5034 }
5035
5036 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
5037 {
5038         struct inode *inode = d_inode(dentry);
5039         struct btrfs_root *root = BTRFS_I(inode)->root;
5040         int err;
5041
5042         if (btrfs_root_readonly(root))
5043                 return -EROFS;
5044
5045         err = setattr_prepare(dentry, attr);
5046         if (err)
5047                 return err;
5048
5049         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
5050                 err = btrfs_setsize(inode, attr);
5051                 if (err)
5052                         return err;
5053         }
5054
5055         if (attr->ia_valid) {
5056                 setattr_copy(inode, attr);
5057                 inode_inc_iversion(inode);
5058                 err = btrfs_dirty_inode(inode);
5059
5060                 if (!err && attr->ia_valid & ATTR_MODE)
5061                         err = posix_acl_chmod(inode, inode->i_mode);
5062         }
5063
5064         return err;
5065 }
5066
5067 /*
5068  * While truncating the inode pages during eviction, we get the VFS calling
5069  * btrfs_invalidatepage() against each page of the inode. This is slow because
5070  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
5071  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
5072  * extent_state structures over and over, wasting lots of time.
5073  *
5074  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
5075  * those expensive operations on a per page basis and do only the ordered io
5076  * finishing, while we release here the extent_map and extent_state structures,
5077  * without the excessive merging and splitting.
5078  */
5079 static void evict_inode_truncate_pages(struct inode *inode)
5080 {
5081         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5082         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
5083         struct rb_node *node;
5084
5085         ASSERT(inode->i_state & I_FREEING);
5086         truncate_inode_pages_final(&inode->i_data);
5087
5088         write_lock(&map_tree->lock);
5089         while (!RB_EMPTY_ROOT(&map_tree->map)) {
5090                 struct extent_map *em;
5091
5092                 node = rb_first(&map_tree->map);
5093                 em = rb_entry(node, struct extent_map, rb_node);
5094                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
5095                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
5096                 remove_extent_mapping(map_tree, em);
5097                 free_extent_map(em);
5098                 if (need_resched()) {
5099                         write_unlock(&map_tree->lock);
5100                         cond_resched();
5101                         write_lock(&map_tree->lock);
5102                 }
5103         }
5104         write_unlock(&map_tree->lock);
5105
5106         /*
5107          * Keep looping until we have no more ranges in the io tree.
5108          * We can have ongoing bios started by readpages (called from readahead)
5109          * that have their endio callback (extent_io.c:end_bio_extent_readpage)
5110          * still in progress (unlocked the pages in the bio but did not yet
5111          * unlocked the ranges in the io tree). Therefore this means some
5112          * ranges can still be locked and eviction started because before
5113          * submitting those bios, which are executed by a separate task (work
5114          * queue kthread), inode references (inode->i_count) were not taken
5115          * (which would be dropped in the end io callback of each bio).
5116          * Therefore here we effectively end up waiting for those bios and
5117          * anyone else holding locked ranges without having bumped the inode's
5118          * reference count - if we don't do it, when they access the inode's
5119          * io_tree to unlock a range it may be too late, leading to an
5120          * use-after-free issue.
5121          */
5122         spin_lock(&io_tree->lock);
5123         while (!RB_EMPTY_ROOT(&io_tree->state)) {
5124                 struct extent_state *state;
5125                 struct extent_state *cached_state = NULL;
5126                 u64 start;
5127                 u64 end;
5128
5129                 node = rb_first(&io_tree->state);
5130                 state = rb_entry(node, struct extent_state, rb_node);
5131                 start = state->start;
5132                 end = state->end;
5133                 spin_unlock(&io_tree->lock);
5134
5135                 lock_extent_bits(io_tree, start, end, &cached_state);
5136
5137                 /*
5138                  * If still has DELALLOC flag, the extent didn't reach disk,
5139                  * and its reserved space won't be freed by delayed_ref.
5140                  * So we need to free its reserved space here.
5141                  * (Refer to comment in btrfs_invalidatepage, case 2)
5142                  *
5143                  * Note, end is the bytenr of last byte, so we need + 1 here.
5144                  */
5145                 if (state->state & EXTENT_DELALLOC)
5146                         btrfs_qgroup_free_data(inode, start, end - start + 1);
5147
5148                 clear_extent_bit(io_tree, start, end,
5149                                  EXTENT_LOCKED | EXTENT_DIRTY |
5150                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
5151                                  EXTENT_DEFRAG, 1, 1,
5152                                  &cached_state, GFP_NOFS);
5153
5154                 cond_resched();
5155                 spin_lock(&io_tree->lock);
5156         }
5157         spin_unlock(&io_tree->lock);
5158 }
5159
5160 void btrfs_evict_inode(struct inode *inode)
5161 {
5162         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5163         struct btrfs_trans_handle *trans;
5164         struct btrfs_root *root = BTRFS_I(inode)->root;
5165         struct btrfs_block_rsv *rsv, *global_rsv;
5166         int steal_from_global = 0;
5167         u64 min_size;
5168         int ret;
5169
5170         trace_btrfs_inode_evict(inode);
5171
5172         if (!root) {
5173                 kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
5174                 return;
5175         }
5176
5177         min_size = btrfs_calc_trunc_metadata_size(fs_info, 1);
5178
5179         evict_inode_truncate_pages(inode);
5180
5181         if (inode->i_nlink &&
5182             ((btrfs_root_refs(&root->root_item) != 0 &&
5183               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
5184              btrfs_is_free_space_inode(inode)))
5185                 goto no_delete;
5186
5187         if (is_bad_inode(inode)) {
5188                 btrfs_orphan_del(NULL, inode);
5189                 goto no_delete;
5190         }
5191         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
5192         if (!special_file(inode->i_mode))
5193                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
5194
5195         btrfs_free_io_failure_record(inode, 0, (u64)-1);
5196
5197         if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) {
5198                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
5199                                  &BTRFS_I(inode)->runtime_flags));
5200                 goto no_delete;
5201         }
5202
5203         if (inode->i_nlink > 0) {
5204                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
5205                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
5206                 goto no_delete;
5207         }
5208
5209         ret = btrfs_commit_inode_delayed_inode(BTRFS_I(inode));
5210         if (ret) {
5211                 btrfs_orphan_del(NULL, inode);
5212                 goto no_delete;
5213         }
5214
5215         rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
5216         if (!rsv) {
5217                 btrfs_orphan_del(NULL, inode);
5218                 goto no_delete;
5219         }
5220         rsv->size = min_size;
5221         rsv->failfast = 1;
5222         global_rsv = &fs_info->global_block_rsv;
5223
5224         btrfs_i_size_write(inode, 0);
5225
5226         /*
5227          * This is a bit simpler than btrfs_truncate since we've already
5228          * reserved our space for our orphan item in the unlink, so we just
5229          * need to reserve some slack space in case we add bytes and update
5230          * inode item when doing the truncate.
5231          */
5232         while (1) {
5233                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
5234                                              BTRFS_RESERVE_FLUSH_LIMIT);
5235
5236                 /*
5237                  * Try and steal from the global reserve since we will
5238                  * likely not use this space anyway, we want to try as
5239                  * hard as possible to get this to work.
5240                  */
5241                 if (ret)
5242                         steal_from_global++;
5243                 else
5244                         steal_from_global = 0;
5245                 ret = 0;
5246
5247                 /*
5248                  * steal_from_global == 0: we reserved stuff, hooray!
5249                  * steal_from_global == 1: we didn't reserve stuff, boo!
5250                  * steal_from_global == 2: we've committed, still not a lot of
5251                  * room but maybe we'll have room in the global reserve this
5252                  * time.
5253                  * steal_from_global == 3: abandon all hope!
5254                  */
5255                 if (steal_from_global > 2) {
5256                         btrfs_warn(fs_info,
5257                                    "Could not get space for a delete, will truncate on mount %d",
5258                                    ret);
5259                         btrfs_orphan_del(NULL, inode);
5260                         btrfs_free_block_rsv(fs_info, rsv);
5261                         goto no_delete;
5262                 }
5263
5264                 trans = btrfs_join_transaction(root);
5265                 if (IS_ERR(trans)) {
5266                         btrfs_orphan_del(NULL, inode);
5267                         btrfs_free_block_rsv(fs_info, rsv);
5268                         goto no_delete;
5269                 }
5270
5271                 /*
5272                  * We can't just steal from the global reserve, we need to make
5273                  * sure there is room to do it, if not we need to commit and try
5274                  * again.
5275                  */
5276                 if (steal_from_global) {
5277                         if (!btrfs_check_space_for_delayed_refs(trans, fs_info))
5278                                 ret = btrfs_block_rsv_migrate(global_rsv, rsv,
5279                                                               min_size, 0);
5280                         else
5281                                 ret = -ENOSPC;
5282                 }
5283
5284                 /*
5285                  * Couldn't steal from the global reserve, we have too much
5286                  * pending stuff built up, commit the transaction and try it
5287                  * again.
5288                  */
5289                 if (ret) {
5290                         ret = btrfs_commit_transaction(trans);
5291                         if (ret) {
5292                                 btrfs_orphan_del(NULL, inode);
5293                                 btrfs_free_block_rsv(fs_info, rsv);
5294                                 goto no_delete;
5295                         }
5296                         continue;
5297                 } else {
5298                         steal_from_global = 0;
5299                 }
5300
5301                 trans->block_rsv = rsv;
5302
5303                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
5304                 if (ret != -ENOSPC && ret != -EAGAIN)
5305                         break;
5306
5307                 trans->block_rsv = &fs_info->trans_block_rsv;
5308                 btrfs_end_transaction(trans);
5309                 trans = NULL;
5310                 btrfs_btree_balance_dirty(fs_info);
5311         }
5312
5313         btrfs_free_block_rsv(fs_info, rsv);
5314
5315         /*
5316          * Errors here aren't a big deal, it just means we leave orphan items
5317          * in the tree.  They will be cleaned up on the next mount.
5318          */
5319         if (ret == 0) {
5320                 trans->block_rsv = root->orphan_block_rsv;
5321                 btrfs_orphan_del(trans, inode);
5322         } else {
5323                 btrfs_orphan_del(NULL, inode);
5324         }
5325
5326         trans->block_rsv = &fs_info->trans_block_rsv;
5327         if (!(root == fs_info->tree_root ||
5328               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
5329                 btrfs_return_ino(root, btrfs_ino(BTRFS_I(inode)));
5330
5331         btrfs_end_transaction(trans);
5332         btrfs_btree_balance_dirty(fs_info);
5333 no_delete:
5334         btrfs_remove_delayed_node(BTRFS_I(inode));
5335         clear_inode(inode);
5336 }
5337
5338 /*
5339  * this returns the key found in the dir entry in the location pointer.
5340  * If no dir entries were found, location->objectid is 0.
5341  */
5342 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
5343                                struct btrfs_key *location)
5344 {
5345         const char *name = dentry->d_name.name;
5346         int namelen = dentry->d_name.len;
5347         struct btrfs_dir_item *di;
5348         struct btrfs_path *path;
5349         struct btrfs_root *root = BTRFS_I(dir)->root;
5350         int ret = 0;
5351
5352         path = btrfs_alloc_path();
5353         if (!path)
5354                 return -ENOMEM;
5355
5356         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(BTRFS_I(dir)),
5357                         name, namelen, 0);
5358         if (IS_ERR(di))
5359                 ret = PTR_ERR(di);
5360
5361         if (IS_ERR_OR_NULL(di))
5362                 goto out_err;
5363
5364         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
5365 out:
5366         btrfs_free_path(path);
5367         return ret;
5368 out_err:
5369         location->objectid = 0;
5370         goto out;
5371 }
5372
5373 /*
5374  * when we hit a tree root in a directory, the btrfs part of the inode
5375  * needs to be changed to reflect the root directory of the tree root.  This
5376  * is kind of like crossing a mount point.
5377  */
5378 static int fixup_tree_root_location(struct btrfs_fs_info *fs_info,
5379                                     struct inode *dir,
5380                                     struct dentry *dentry,
5381                                     struct btrfs_key *location,
5382                                     struct btrfs_root **sub_root)
5383 {
5384         struct btrfs_path *path;
5385         struct btrfs_root *new_root;
5386         struct btrfs_root_ref *ref;
5387         struct extent_buffer *leaf;
5388         struct btrfs_key key;
5389         int ret;
5390         int err = 0;
5391
5392         path = btrfs_alloc_path();
5393         if (!path) {
5394                 err = -ENOMEM;
5395                 goto out;
5396         }
5397
5398         err = -ENOENT;
5399         key.objectid = BTRFS_I(dir)->root->root_key.objectid;
5400         key.type = BTRFS_ROOT_REF_KEY;
5401         key.offset = location->objectid;
5402
5403         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
5404         if (ret) {
5405                 if (ret < 0)
5406                         err = ret;
5407                 goto out;
5408         }
5409
5410         leaf = path->nodes[0];
5411         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
5412         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(BTRFS_I(dir)) ||
5413             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
5414                 goto out;
5415
5416         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
5417                                    (unsigned long)(ref + 1),
5418                                    dentry->d_name.len);
5419         if (ret)
5420                 goto out;
5421
5422         btrfs_release_path(path);
5423
5424         new_root = btrfs_read_fs_root_no_name(fs_info, location);
5425         if (IS_ERR(new_root)) {
5426                 err = PTR_ERR(new_root);
5427                 goto out;
5428         }
5429
5430         *sub_root = new_root;
5431         location->objectid = btrfs_root_dirid(&new_root->root_item);
5432         location->type = BTRFS_INODE_ITEM_KEY;
5433         location->offset = 0;
5434         err = 0;
5435 out:
5436         btrfs_free_path(path);
5437         return err;
5438 }
5439
5440 static void inode_tree_add(struct inode *inode)
5441 {
5442         struct btrfs_root *root = BTRFS_I(inode)->root;
5443         struct btrfs_inode *entry;
5444         struct rb_node **p;
5445         struct rb_node *parent;
5446         struct rb_node *new = &BTRFS_I(inode)->rb_node;
5447         u64 ino = btrfs_ino(BTRFS_I(inode));
5448
5449         if (inode_unhashed(inode))
5450                 return;
5451         parent = NULL;
5452         spin_lock(&root->inode_lock);
5453         p = &root->inode_tree.rb_node;
5454         while (*p) {
5455                 parent = *p;
5456                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
5457
5458                 if (ino < btrfs_ino(BTRFS_I(&entry->vfs_inode)))
5459                         p = &parent->rb_left;
5460                 else if (ino > btrfs_ino(BTRFS_I(&entry->vfs_inode)))
5461                         p = &parent->rb_right;
5462                 else {
5463                         WARN_ON(!(entry->vfs_inode.i_state &
5464                                   (I_WILL_FREE | I_FREEING)));
5465                         rb_replace_node(parent, new, &root->inode_tree);
5466                         RB_CLEAR_NODE(parent);
5467                         spin_unlock(&root->inode_lock);
5468                         return;
5469                 }
5470         }
5471         rb_link_node(new, parent, p);
5472         rb_insert_color(new, &root->inode_tree);
5473         spin_unlock(&root->inode_lock);
5474 }
5475
5476 static void inode_tree_del(struct inode *inode)
5477 {
5478         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5479         struct btrfs_root *root = BTRFS_I(inode)->root;
5480         int empty = 0;
5481
5482         spin_lock(&root->inode_lock);
5483         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
5484                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
5485                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
5486                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5487         }
5488         spin_unlock(&root->inode_lock);
5489
5490         if (empty && btrfs_root_refs(&root->root_item) == 0) {
5491                 synchronize_srcu(&fs_info->subvol_srcu);
5492                 spin_lock(&root->inode_lock);
5493                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5494                 spin_unlock(&root->inode_lock);
5495                 if (empty)
5496                         btrfs_add_dead_root(root);
5497         }
5498 }
5499
5500 void btrfs_invalidate_inodes(struct btrfs_root *root)
5501 {
5502         struct btrfs_fs_info *fs_info = root->fs_info;
5503         struct rb_node *node;
5504         struct rb_node *prev;
5505         struct btrfs_inode *entry;
5506         struct inode *inode;
5507         u64 objectid = 0;
5508
5509         if (!test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
5510                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
5511
5512         spin_lock(&root->inode_lock);
5513 again:
5514         node = root->inode_tree.rb_node;
5515         prev = NULL;
5516         while (node) {
5517                 prev = node;
5518                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5519
5520                 if (objectid < btrfs_ino(BTRFS_I(&entry->vfs_inode)))
5521                         node = node->rb_left;
5522                 else if (objectid > btrfs_ino(BTRFS_I(&entry->vfs_inode)))
5523                         node = node->rb_right;
5524                 else
5525                         break;
5526         }
5527         if (!node) {
5528                 while (prev) {
5529                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
5530                         if (objectid <= btrfs_ino(BTRFS_I(&entry->vfs_inode))) {
5531                                 node = prev;
5532                                 break;
5533                         }
5534                         prev = rb_next(prev);
5535                 }
5536         }
5537         while (node) {
5538                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5539                 objectid = btrfs_ino(BTRFS_I(&entry->vfs_inode)) + 1;
5540                 inode = igrab(&entry->vfs_inode);
5541                 if (inode) {
5542                         spin_unlock(&root->inode_lock);
5543                         if (atomic_read(&inode->i_count) > 1)
5544                                 d_prune_aliases(inode);
5545                         /*
5546                          * btrfs_drop_inode will have it removed from
5547                          * the inode cache when its usage count
5548                          * hits zero.
5549                          */
5550                         iput(inode);
5551                         cond_resched();
5552                         spin_lock(&root->inode_lock);
5553                         goto again;
5554                 }
5555
5556                 if (cond_resched_lock(&root->inode_lock))
5557                         goto again;
5558
5559                 node = rb_next(node);
5560         }
5561         spin_unlock(&root->inode_lock);
5562 }
5563
5564 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5565 {
5566         struct btrfs_iget_args *args = p;
5567         inode->i_ino = args->location->objectid;
5568         memcpy(&BTRFS_I(inode)->location, args->location,
5569                sizeof(*args->location));
5570         BTRFS_I(inode)->root = args->root;
5571         return 0;
5572 }
5573
5574 static int btrfs_find_actor(struct inode *inode, void *opaque)
5575 {
5576         struct btrfs_iget_args *args = opaque;
5577         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5578                 args->root == BTRFS_I(inode)->root;
5579 }
5580
5581 static struct inode *btrfs_iget_locked(struct super_block *s,
5582                                        struct btrfs_key *location,
5583                                        struct btrfs_root *root)
5584 {
5585         struct inode *inode;
5586         struct btrfs_iget_args args;
5587         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5588
5589         args.location = location;
5590         args.root = root;
5591
5592         inode = iget5_locked(s, hashval, btrfs_find_actor,
5593                              btrfs_init_locked_inode,
5594                              (void *)&args);
5595         return inode;
5596 }
5597
5598 /* Get an inode object given its location and corresponding root.
5599  * Returns in *is_new if the inode was read from disk
5600  */
5601 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5602                          struct btrfs_root *root, int *new)
5603 {
5604         struct inode *inode;
5605
5606         inode = btrfs_iget_locked(s, location, root);
5607         if (!inode)
5608                 return ERR_PTR(-ENOMEM);
5609
5610         if (inode->i_state & I_NEW) {
5611                 int ret;
5612
5613                 ret = btrfs_read_locked_inode(inode);
5614                 if (!is_bad_inode(inode)) {
5615                         inode_tree_add(inode);
5616                         unlock_new_inode(inode);
5617                         if (new)
5618                                 *new = 1;
5619                 } else {
5620                         unlock_new_inode(inode);
5621                         iput(inode);
5622                         ASSERT(ret < 0);
5623                         inode = ERR_PTR(ret < 0 ? ret : -ESTALE);
5624                 }
5625         }
5626
5627         return inode;
5628 }
5629
5630 static struct inode *new_simple_dir(struct super_block *s,
5631                                     struct btrfs_key *key,
5632                                     struct btrfs_root *root)
5633 {
5634         struct inode *inode = new_inode(s);
5635
5636         if (!inode)
5637                 return ERR_PTR(-ENOMEM);
5638
5639         BTRFS_I(inode)->root = root;
5640         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5641         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5642
5643         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5644         inode->i_op = &btrfs_dir_ro_inode_operations;
5645         inode->i_opflags &= ~IOP_XATTR;
5646         inode->i_fop = &simple_dir_operations;
5647         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5648         inode->i_mtime = current_time(inode);
5649         inode->i_atime = inode->i_mtime;
5650         inode->i_ctime = inode->i_mtime;
5651         BTRFS_I(inode)->i_otime = inode->i_mtime;
5652
5653         return inode;
5654 }
5655
5656 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5657 {
5658         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
5659         struct inode *inode;
5660         struct btrfs_root *root = BTRFS_I(dir)->root;
5661         struct btrfs_root *sub_root = root;
5662         struct btrfs_key location;
5663         int index;
5664         int ret = 0;
5665
5666         if (dentry->d_name.len > BTRFS_NAME_LEN)
5667                 return ERR_PTR(-ENAMETOOLONG);
5668
5669         ret = btrfs_inode_by_name(dir, dentry, &location);
5670         if (ret < 0)
5671                 return ERR_PTR(ret);
5672
5673         if (location.objectid == 0)
5674                 return ERR_PTR(-ENOENT);
5675
5676         if (location.type == BTRFS_INODE_ITEM_KEY) {
5677                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5678                 return inode;
5679         }
5680
5681         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
5682
5683         index = srcu_read_lock(&fs_info->subvol_srcu);
5684         ret = fixup_tree_root_location(fs_info, dir, dentry,
5685                                        &location, &sub_root);
5686         if (ret < 0) {
5687                 if (ret != -ENOENT)
5688                         inode = ERR_PTR(ret);
5689                 else
5690                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5691         } else {
5692                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5693         }
5694         srcu_read_unlock(&fs_info->subvol_srcu, index);
5695
5696         if (!IS_ERR(inode) && root != sub_root) {
5697                 down_read(&fs_info->cleanup_work_sem);
5698                 if (!(inode->i_sb->s_flags & MS_RDONLY))
5699                         ret = btrfs_orphan_cleanup(sub_root);
5700                 up_read(&fs_info->cleanup_work_sem);
5701                 if (ret) {
5702                         iput(inode);
5703                         inode = ERR_PTR(ret);
5704                 }
5705         }
5706
5707         return inode;
5708 }
5709
5710 static int btrfs_dentry_delete(const struct dentry *dentry)
5711 {
5712         struct btrfs_root *root;
5713         struct inode *inode = d_inode(dentry);
5714
5715         if (!inode && !IS_ROOT(dentry))
5716                 inode = d_inode(dentry->d_parent);
5717
5718         if (inode) {
5719                 root = BTRFS_I(inode)->root;
5720                 if (btrfs_root_refs(&root->root_item) == 0)
5721                         return 1;
5722
5723                 if (btrfs_ino(BTRFS_I(inode)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5724                         return 1;
5725         }
5726         return 0;
5727 }
5728
5729 static void btrfs_dentry_release(struct dentry *dentry)
5730 {
5731         kfree(dentry->d_fsdata);
5732 }
5733
5734 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5735                                    unsigned int flags)
5736 {
5737         struct inode *inode;
5738
5739         inode = btrfs_lookup_dentry(dir, dentry);
5740         if (IS_ERR(inode)) {
5741                 if (PTR_ERR(inode) == -ENOENT)
5742                         inode = NULL;
5743                 else
5744                         return ERR_CAST(inode);
5745         }
5746
5747         return d_splice_alias(inode, dentry);
5748 }
5749
5750 unsigned char btrfs_filetype_table[] = {
5751         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5752 };
5753
5754 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5755 {
5756         struct inode *inode = file_inode(file);
5757         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5758         struct btrfs_root *root = BTRFS_I(inode)->root;
5759         struct btrfs_item *item;
5760         struct btrfs_dir_item *di;
5761         struct btrfs_key key;
5762         struct btrfs_key found_key;
5763         struct btrfs_path *path;
5764         struct list_head ins_list;
5765         struct list_head del_list;
5766         int ret;
5767         struct extent_buffer *leaf;
5768         int slot;
5769         unsigned char d_type;
5770         int over = 0;
5771         char tmp_name[32];
5772         char *name_ptr;
5773         int name_len;
5774         bool put = false;
5775         struct btrfs_key location;
5776
5777         if (!dir_emit_dots(file, ctx))
5778                 return 0;
5779
5780         path = btrfs_alloc_path();
5781         if (!path)
5782                 return -ENOMEM;
5783
5784         path->reada = READA_FORWARD;
5785
5786         INIT_LIST_HEAD(&ins_list);
5787         INIT_LIST_HEAD(&del_list);
5788         put = btrfs_readdir_get_delayed_items(inode, &ins_list, &del_list);
5789
5790         key.type = BTRFS_DIR_INDEX_KEY;
5791         key.offset = ctx->pos;
5792         key.objectid = btrfs_ino(BTRFS_I(inode));
5793
5794         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5795         if (ret < 0)
5796                 goto err;
5797
5798         while (1) {
5799                 leaf = path->nodes[0];
5800                 slot = path->slots[0];
5801                 if (slot >= btrfs_header_nritems(leaf)) {
5802                         ret = btrfs_next_leaf(root, path);
5803                         if (ret < 0)
5804                                 goto err;
5805                         else if (ret > 0)
5806                                 break;
5807                         continue;
5808                 }
5809
5810                 item = btrfs_item_nr(slot);
5811                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5812
5813                 if (found_key.objectid != key.objectid)
5814                         break;
5815                 if (found_key.type != BTRFS_DIR_INDEX_KEY)
5816                         break;
5817                 if (found_key.offset < ctx->pos)
5818                         goto next;
5819                 if (btrfs_should_delete_dir_index(&del_list, found_key.offset))
5820                         goto next;
5821
5822                 ctx->pos = found_key.offset;
5823
5824                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5825                 if (verify_dir_item(fs_info, leaf, di))
5826                         goto next;
5827
5828                 name_len = btrfs_dir_name_len(leaf, di);
5829                 if (name_len <= sizeof(tmp_name)) {
5830                         name_ptr = tmp_name;
5831                 } else {
5832                         name_ptr = kmalloc(name_len, GFP_KERNEL);
5833                         if (!name_ptr) {
5834                                 ret = -ENOMEM;
5835                                 goto err;
5836                         }
5837                 }
5838                 read_extent_buffer(leaf, name_ptr, (unsigned long)(di + 1),
5839                                    name_len);
5840
5841                 d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
5842                 btrfs_dir_item_key_to_cpu(leaf, di, &location);
5843
5844                 over = !dir_emit(ctx, name_ptr, name_len, location.objectid,
5845                                  d_type);
5846
5847                 if (name_ptr != tmp_name)
5848                         kfree(name_ptr);
5849
5850                 if (over)
5851                         goto nopos;
5852                 ctx->pos++;
5853 next:
5854                 path->slots[0]++;
5855         }
5856
5857         ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5858         if (ret)
5859                 goto nopos;
5860
5861         /*
5862          * Stop new entries from being returned after we return the last
5863          * entry.
5864          *
5865          * New directory entries are assigned a strictly increasing
5866          * offset.  This means that new entries created during readdir
5867          * are *guaranteed* to be seen in the future by that readdir.
5868          * This has broken buggy programs which operate on names as
5869          * they're returned by readdir.  Until we re-use freed offsets
5870          * we have this hack to stop new entries from being returned
5871          * under the assumption that they'll never reach this huge
5872          * offset.
5873          *
5874          * This is being careful not to overflow 32bit loff_t unless the
5875          * last entry requires it because doing so has broken 32bit apps
5876          * in the past.
5877          */
5878         if (ctx->pos >= INT_MAX)
5879                 ctx->pos = LLONG_MAX;
5880         else
5881                 ctx->pos = INT_MAX;
5882 nopos:
5883         ret = 0;
5884 err:
5885         if (put)
5886                 btrfs_readdir_put_delayed_items(inode, &ins_list, &del_list);
5887         btrfs_free_path(path);
5888         return ret;
5889 }
5890
5891 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
5892 {
5893         struct btrfs_root *root = BTRFS_I(inode)->root;
5894         struct btrfs_trans_handle *trans;
5895         int ret = 0;
5896         bool nolock = false;
5897
5898         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5899                 return 0;
5900
5901         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
5902                 nolock = true;
5903
5904         if (wbc->sync_mode == WB_SYNC_ALL) {
5905                 if (nolock)
5906                         trans = btrfs_join_transaction_nolock(root);
5907                 else
5908                         trans = btrfs_join_transaction(root);
5909                 if (IS_ERR(trans))
5910                         return PTR_ERR(trans);
5911                 ret = btrfs_commit_transaction(trans);
5912         }
5913         return ret;
5914 }
5915
5916 /*
5917  * This is somewhat expensive, updating the tree every time the
5918  * inode changes.  But, it is most likely to find the inode in cache.
5919  * FIXME, needs more benchmarking...there are no reasons other than performance
5920  * to keep or drop this code.
5921  */
5922 static int btrfs_dirty_inode(struct inode *inode)
5923 {
5924         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5925         struct btrfs_root *root = BTRFS_I(inode)->root;
5926         struct btrfs_trans_handle *trans;
5927         int ret;
5928
5929         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5930                 return 0;
5931
5932         trans = btrfs_join_transaction(root);
5933         if (IS_ERR(trans))
5934                 return PTR_ERR(trans);
5935
5936         ret = btrfs_update_inode(trans, root, inode);
5937         if (ret && ret == -ENOSPC) {
5938                 /* whoops, lets try again with the full transaction */
5939                 btrfs_end_transaction(trans);
5940                 trans = btrfs_start_transaction(root, 1);
5941                 if (IS_ERR(trans))
5942                         return PTR_ERR(trans);
5943
5944                 ret = btrfs_update_inode(trans, root, inode);
5945         }
5946         btrfs_end_transaction(trans);
5947         if (BTRFS_I(inode)->delayed_node)
5948                 btrfs_balance_delayed_items(fs_info);
5949
5950         return ret;
5951 }
5952
5953 /*
5954  * This is a copy of file_update_time.  We need this so we can return error on
5955  * ENOSPC for updating the inode in the case of file write and mmap writes.
5956  */
5957 static int btrfs_update_time(struct inode *inode, struct timespec *now,
5958                              int flags)
5959 {
5960         struct btrfs_root *root = BTRFS_I(inode)->root;
5961
5962         if (btrfs_root_readonly(root))
5963                 return -EROFS;
5964
5965         if (flags & S_VERSION)
5966                 inode_inc_iversion(inode);
5967         if (flags & S_CTIME)
5968                 inode->i_ctime = *now;
5969         if (flags & S_MTIME)
5970                 inode->i_mtime = *now;
5971         if (flags & S_ATIME)
5972                 inode->i_atime = *now;
5973         return btrfs_dirty_inode(inode);
5974 }
5975
5976 /*
5977  * find the highest existing sequence number in a directory
5978  * and then set the in-memory index_cnt variable to reflect
5979  * free sequence numbers
5980  */
5981 static int btrfs_set_inode_index_count(struct inode *inode)
5982 {
5983         struct btrfs_root *root = BTRFS_I(inode)->root;
5984         struct btrfs_key key, found_key;
5985         struct btrfs_path *path;
5986         struct extent_buffer *leaf;
5987         int ret;
5988
5989         key.objectid = btrfs_ino(BTRFS_I(inode));
5990         key.type = BTRFS_DIR_INDEX_KEY;
5991         key.offset = (u64)-1;
5992
5993         path = btrfs_alloc_path();
5994         if (!path)
5995                 return -ENOMEM;
5996
5997         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5998         if (ret < 0)
5999                 goto out;
6000         /* FIXME: we should be able to handle this */
6001         if (ret == 0)
6002                 goto out;
6003         ret = 0;
6004
6005         /*
6006          * MAGIC NUMBER EXPLANATION:
6007          * since we search a directory based on f_pos we have to start at 2
6008          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
6009          * else has to start at 2
6010          */
6011         if (path->slots[0] == 0) {
6012                 BTRFS_I(inode)->index_cnt = 2;
6013                 goto out;
6014         }
6015
6016         path->slots[0]--;
6017
6018         leaf = path->nodes[0];
6019         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6020
6021         if (found_key.objectid != btrfs_ino(BTRFS_I(inode)) ||
6022             found_key.type != BTRFS_DIR_INDEX_KEY) {
6023                 BTRFS_I(inode)->index_cnt = 2;
6024                 goto out;
6025         }
6026
6027         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
6028 out:
6029         btrfs_free_path(path);
6030         return ret;
6031 }
6032
6033 /*
6034  * helper to find a free sequence number in a given directory.  This current
6035  * code is very simple, later versions will do smarter things in the btree
6036  */
6037 int btrfs_set_inode_index(struct inode *dir, u64 *index)
6038 {
6039         int ret = 0;
6040
6041         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
6042                 ret = btrfs_inode_delayed_dir_index_count(BTRFS_I(dir));
6043                 if (ret) {
6044                         ret = btrfs_set_inode_index_count(dir);
6045                         if (ret)
6046                                 return ret;
6047                 }
6048         }
6049
6050         *index = BTRFS_I(dir)->index_cnt;
6051         BTRFS_I(dir)->index_cnt++;
6052
6053         return ret;
6054 }
6055
6056 static int btrfs_insert_inode_locked(struct inode *inode)
6057 {
6058         struct btrfs_iget_args args;
6059         args.location = &BTRFS_I(inode)->location;
6060         args.root = BTRFS_I(inode)->root;
6061
6062         return insert_inode_locked4(inode,
6063                    btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root),
6064                    btrfs_find_actor, &args);
6065 }
6066
6067 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
6068                                      struct btrfs_root *root,
6069                                      struct inode *dir,
6070                                      const char *name, int name_len,
6071                                      u64 ref_objectid, u64 objectid,
6072                                      umode_t mode, u64 *index)
6073 {
6074         struct btrfs_fs_info *fs_info = root->fs_info;
6075         struct inode *inode;
6076         struct btrfs_inode_item *inode_item;
6077         struct btrfs_key *location;
6078         struct btrfs_path *path;
6079         struct btrfs_inode_ref *ref;
6080         struct btrfs_key key[2];
6081         u32 sizes[2];
6082         int nitems = name ? 2 : 1;
6083         unsigned long ptr;
6084         int ret;
6085
6086         path = btrfs_alloc_path();
6087         if (!path)
6088                 return ERR_PTR(-ENOMEM);
6089
6090         inode = new_inode(fs_info->sb);
6091         if (!inode) {
6092                 btrfs_free_path(path);
6093                 return ERR_PTR(-ENOMEM);
6094         }
6095
6096         /*
6097          * O_TMPFILE, set link count to 0, so that after this point,
6098          * we fill in an inode item with the correct link count.
6099          */
6100         if (!name)
6101                 set_nlink(inode, 0);
6102
6103         /*
6104          * we have to initialize this early, so we can reclaim the inode
6105          * number if we fail afterwards in this function.
6106          */
6107         inode->i_ino = objectid;
6108
6109         if (dir && name) {
6110                 trace_btrfs_inode_request(dir);
6111
6112                 ret = btrfs_set_inode_index(dir, index);
6113                 if (ret) {
6114                         btrfs_free_path(path);
6115                         iput(inode);
6116                         return ERR_PTR(ret);
6117                 }
6118         } else if (dir) {
6119                 *index = 0;
6120         }
6121         /*
6122          * index_cnt is ignored for everything but a dir,
6123          * btrfs_get_inode_index_count has an explanation for the magic
6124          * number
6125          */
6126         BTRFS_I(inode)->index_cnt = 2;
6127         BTRFS_I(inode)->dir_index = *index;
6128         BTRFS_I(inode)->root = root;
6129         BTRFS_I(inode)->generation = trans->transid;
6130         inode->i_generation = BTRFS_I(inode)->generation;
6131
6132         /*
6133          * We could have gotten an inode number from somebody who was fsynced
6134          * and then removed in this same transaction, so let's just set full
6135          * sync since it will be a full sync anyway and this will blow away the
6136          * old info in the log.
6137          */
6138         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
6139
6140         key[0].objectid = objectid;
6141         key[0].type = BTRFS_INODE_ITEM_KEY;
6142         key[0].offset = 0;
6143
6144         sizes[0] = sizeof(struct btrfs_inode_item);
6145
6146         if (name) {
6147                 /*
6148                  * Start new inodes with an inode_ref. This is slightly more
6149                  * efficient for small numbers of hard links since they will
6150                  * be packed into one item. Extended refs will kick in if we
6151                  * add more hard links than can fit in the ref item.
6152                  */
6153                 key[1].objectid = objectid;
6154                 key[1].type = BTRFS_INODE_REF_KEY;
6155                 key[1].offset = ref_objectid;
6156
6157                 sizes[1] = name_len + sizeof(*ref);
6158         }
6159
6160         location = &BTRFS_I(inode)->location;
6161         location->objectid = objectid;
6162         location->offset = 0;
6163         location->type = BTRFS_INODE_ITEM_KEY;
6164
6165         ret = btrfs_insert_inode_locked(inode);
6166         if (ret < 0)
6167                 goto fail;
6168
6169         path->leave_spinning = 1;
6170         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
6171         if (ret != 0)
6172                 goto fail_unlock;
6173
6174         inode_init_owner(inode, dir, mode);
6175         inode_set_bytes(inode, 0);
6176
6177         inode->i_mtime = current_time(inode);
6178         inode->i_atime = inode->i_mtime;
6179         inode->i_ctime = inode->i_mtime;
6180         BTRFS_I(inode)->i_otime = inode->i_mtime;
6181
6182         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
6183                                   struct btrfs_inode_item);
6184         memzero_extent_buffer(path->nodes[0], (unsigned long)inode_item,
6185                              sizeof(*inode_item));
6186         fill_inode_item(trans, path->nodes[0], inode_item, inode);
6187
6188         if (name) {
6189                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
6190                                      struct btrfs_inode_ref);
6191                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
6192                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
6193                 ptr = (unsigned long)(ref + 1);
6194                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
6195         }
6196
6197         btrfs_mark_buffer_dirty(path->nodes[0]);
6198         btrfs_free_path(path);
6199
6200         btrfs_inherit_iflags(inode, dir);
6201
6202         if (S_ISREG(mode)) {
6203                 if (btrfs_test_opt(fs_info, NODATASUM))
6204                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
6205                 if (btrfs_test_opt(fs_info, NODATACOW))
6206                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
6207                                 BTRFS_INODE_NODATASUM;
6208         }
6209
6210         inode_tree_add(inode);
6211
6212         trace_btrfs_inode_new(inode);
6213         btrfs_set_inode_last_trans(trans, inode);
6214
6215         btrfs_update_root_times(trans, root);
6216
6217         ret = btrfs_inode_inherit_props(trans, inode, dir);
6218         if (ret)
6219                 btrfs_err(fs_info,
6220                           "error inheriting props for ino %llu (root %llu): %d",
6221                         btrfs_ino(BTRFS_I(inode)), root->root_key.objectid, ret);
6222
6223         return inode;
6224
6225 fail_unlock:
6226         unlock_new_inode(inode);
6227 fail:
6228         if (dir && name)
6229                 BTRFS_I(dir)->index_cnt--;
6230         btrfs_free_path(path);
6231         iput(inode);
6232         return ERR_PTR(ret);
6233 }
6234
6235 static inline u8 btrfs_inode_type(struct inode *inode)
6236 {
6237         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
6238 }
6239
6240 /*
6241  * utility function to add 'inode' into 'parent_inode' with
6242  * a give name and a given sequence number.
6243  * if 'add_backref' is true, also insert a backref from the
6244  * inode to the parent directory.
6245  */
6246 int btrfs_add_link(struct btrfs_trans_handle *trans,
6247                    struct inode *parent_inode, struct inode *inode,
6248                    const char *name, int name_len, int add_backref, u64 index)
6249 {
6250         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
6251         int ret = 0;
6252         struct btrfs_key key;
6253         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
6254         u64 ino = btrfs_ino(BTRFS_I(inode));
6255         u64 parent_ino = btrfs_ino(BTRFS_I(parent_inode));
6256
6257         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6258                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
6259         } else {
6260                 key.objectid = ino;
6261                 key.type = BTRFS_INODE_ITEM_KEY;
6262                 key.offset = 0;
6263         }
6264
6265         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6266                 ret = btrfs_add_root_ref(trans, fs_info, key.objectid,
6267                                          root->root_key.objectid, parent_ino,
6268                                          index, name, name_len);
6269         } else if (add_backref) {
6270                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
6271                                              parent_ino, index);
6272         }
6273
6274         /* Nothing to clean up yet */
6275         if (ret)
6276                 return ret;
6277
6278         ret = btrfs_insert_dir_item(trans, root, name, name_len,
6279                                     parent_inode, &key,
6280                                     btrfs_inode_type(inode), index);
6281         if (ret == -EEXIST || ret == -EOVERFLOW)
6282                 goto fail_dir_item;
6283         else if (ret) {
6284                 btrfs_abort_transaction(trans, ret);
6285                 return ret;
6286         }
6287
6288         btrfs_i_size_write(parent_inode, parent_inode->i_size +
6289                            name_len * 2);
6290         inode_inc_iversion(parent_inode);
6291         parent_inode->i_mtime = parent_inode->i_ctime =
6292                 current_time(parent_inode);
6293         ret = btrfs_update_inode(trans, root, parent_inode);
6294         if (ret)
6295                 btrfs_abort_transaction(trans, ret);
6296         return ret;
6297
6298 fail_dir_item:
6299         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6300                 u64 local_index;
6301                 int err;
6302                 err = btrfs_del_root_ref(trans, fs_info, key.objectid,
6303                                          root->root_key.objectid, parent_ino,
6304                                          &local_index, name, name_len);
6305
6306         } else if (add_backref) {
6307                 u64 local_index;
6308                 int err;
6309
6310                 err = btrfs_del_inode_ref(trans, root, name, name_len,
6311                                           ino, parent_ino, &local_index);
6312         }
6313         return ret;
6314 }
6315
6316 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
6317                             struct inode *dir, struct dentry *dentry,
6318                             struct inode *inode, int backref, u64 index)
6319 {
6320         int err = btrfs_add_link(trans, dir, inode,
6321                                  dentry->d_name.name, dentry->d_name.len,
6322                                  backref, index);
6323         if (err > 0)
6324                 err = -EEXIST;
6325         return err;
6326 }
6327
6328 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
6329                         umode_t mode, dev_t rdev)
6330 {
6331         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6332         struct btrfs_trans_handle *trans;
6333         struct btrfs_root *root = BTRFS_I(dir)->root;
6334         struct inode *inode = NULL;
6335         int err;
6336         int drop_inode = 0;
6337         u64 objectid;
6338         u64 index = 0;
6339
6340         /*
6341          * 2 for inode item and ref
6342          * 2 for dir items
6343          * 1 for xattr if selinux is on
6344          */
6345         trans = btrfs_start_transaction(root, 5);
6346         if (IS_ERR(trans))
6347                 return PTR_ERR(trans);
6348
6349         err = btrfs_find_free_ino(root, &objectid);
6350         if (err)
6351                 goto out_unlock;
6352
6353         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6354                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6355                         mode, &index);
6356         if (IS_ERR(inode)) {
6357                 err = PTR_ERR(inode);
6358                 goto out_unlock;
6359         }
6360
6361         /*
6362         * If the active LSM wants to access the inode during
6363         * d_instantiate it needs these. Smack checks to see
6364         * if the filesystem supports xattrs by looking at the
6365         * ops vector.
6366         */
6367         inode->i_op = &btrfs_special_inode_operations;
6368         init_special_inode(inode, inode->i_mode, rdev);
6369
6370         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6371         if (err)
6372                 goto out_unlock_inode;
6373
6374         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6375         if (err) {
6376                 goto out_unlock_inode;
6377         } else {
6378                 btrfs_update_inode(trans, root, inode);
6379                 unlock_new_inode(inode);
6380                 d_instantiate(dentry, inode);
6381         }
6382
6383 out_unlock:
6384         btrfs_end_transaction(trans);
6385         btrfs_balance_delayed_items(fs_info);
6386         btrfs_btree_balance_dirty(fs_info);
6387         if (drop_inode) {
6388                 inode_dec_link_count(inode);
6389                 iput(inode);
6390         }
6391         return err;
6392
6393 out_unlock_inode:
6394         drop_inode = 1;
6395         unlock_new_inode(inode);
6396         goto out_unlock;
6397
6398 }
6399
6400 static int btrfs_create(struct inode *dir, struct dentry *dentry,
6401                         umode_t mode, bool excl)
6402 {
6403         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6404         struct btrfs_trans_handle *trans;
6405         struct btrfs_root *root = BTRFS_I(dir)->root;
6406         struct inode *inode = NULL;
6407         int drop_inode_on_err = 0;
6408         int err;
6409         u64 objectid;
6410         u64 index = 0;
6411
6412         /*
6413          * 2 for inode item and ref
6414          * 2 for dir items
6415          * 1 for xattr if selinux is on
6416          */
6417         trans = btrfs_start_transaction(root, 5);
6418         if (IS_ERR(trans))
6419                 return PTR_ERR(trans);
6420
6421         err = btrfs_find_free_ino(root, &objectid);
6422         if (err)
6423                 goto out_unlock;
6424
6425         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6426                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6427                         mode, &index);
6428         if (IS_ERR(inode)) {
6429                 err = PTR_ERR(inode);
6430                 goto out_unlock;
6431         }
6432         drop_inode_on_err = 1;
6433         /*
6434         * If the active LSM wants to access the inode during
6435         * d_instantiate it needs these. Smack checks to see
6436         * if the filesystem supports xattrs by looking at the
6437         * ops vector.
6438         */
6439         inode->i_fop = &btrfs_file_operations;
6440         inode->i_op = &btrfs_file_inode_operations;
6441         inode->i_mapping->a_ops = &btrfs_aops;
6442
6443         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6444         if (err)
6445                 goto out_unlock_inode;
6446
6447         err = btrfs_update_inode(trans, root, inode);
6448         if (err)
6449                 goto out_unlock_inode;
6450
6451         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6452         if (err)
6453                 goto out_unlock_inode;
6454
6455         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
6456         unlock_new_inode(inode);
6457         d_instantiate(dentry, inode);
6458
6459 out_unlock:
6460         btrfs_end_transaction(trans);
6461         if (err && drop_inode_on_err) {
6462                 inode_dec_link_count(inode);
6463                 iput(inode);
6464         }
6465         btrfs_balance_delayed_items(fs_info);
6466         btrfs_btree_balance_dirty(fs_info);
6467         return err;
6468
6469 out_unlock_inode:
6470         unlock_new_inode(inode);
6471         goto out_unlock;
6472
6473 }
6474
6475 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
6476                       struct dentry *dentry)
6477 {
6478         struct btrfs_trans_handle *trans = NULL;
6479         struct btrfs_root *root = BTRFS_I(dir)->root;
6480         struct inode *inode = d_inode(old_dentry);
6481         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
6482         u64 index;
6483         int err;
6484         int drop_inode = 0;
6485
6486         /* do not allow sys_link's with other subvols of the same device */
6487         if (root->objectid != BTRFS_I(inode)->root->objectid)
6488                 return -EXDEV;
6489
6490         if (inode->i_nlink >= BTRFS_LINK_MAX)
6491                 return -EMLINK;
6492
6493         err = btrfs_set_inode_index(dir, &index);
6494         if (err)
6495                 goto fail;
6496
6497         /*
6498          * 2 items for inode and inode ref
6499          * 2 items for dir items
6500          * 1 item for parent inode
6501          */
6502         trans = btrfs_start_transaction(root, 5);
6503         if (IS_ERR(trans)) {
6504                 err = PTR_ERR(trans);
6505                 trans = NULL;
6506                 goto fail;
6507         }
6508
6509         /* There are several dir indexes for this inode, clear the cache. */
6510         BTRFS_I(inode)->dir_index = 0ULL;
6511         inc_nlink(inode);
6512         inode_inc_iversion(inode);
6513         inode->i_ctime = current_time(inode);
6514         ihold(inode);
6515         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
6516
6517         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
6518
6519         if (err) {
6520                 drop_inode = 1;
6521         } else {
6522                 struct dentry *parent = dentry->d_parent;
6523                 err = btrfs_update_inode(trans, root, inode);
6524                 if (err)
6525                         goto fail;
6526                 if (inode->i_nlink == 1) {
6527                         /*
6528                          * If new hard link count is 1, it's a file created
6529                          * with open(2) O_TMPFILE flag.
6530                          */
6531                         err = btrfs_orphan_del(trans, inode);
6532                         if (err)
6533                                 goto fail;
6534                 }
6535                 d_instantiate(dentry, inode);
6536                 btrfs_log_new_name(trans, BTRFS_I(inode), NULL, parent);
6537         }
6538
6539         btrfs_balance_delayed_items(fs_info);
6540 fail:
6541         if (trans)
6542                 btrfs_end_transaction(trans);
6543         if (drop_inode) {
6544                 inode_dec_link_count(inode);
6545                 iput(inode);
6546         }
6547         btrfs_btree_balance_dirty(fs_info);
6548         return err;
6549 }
6550
6551 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6552 {
6553         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6554         struct inode *inode = NULL;
6555         struct btrfs_trans_handle *trans;
6556         struct btrfs_root *root = BTRFS_I(dir)->root;
6557         int err = 0;
6558         int drop_on_err = 0;
6559         u64 objectid = 0;
6560         u64 index = 0;
6561
6562         /*
6563          * 2 items for inode and ref
6564          * 2 items for dir items
6565          * 1 for xattr if selinux is on
6566          */
6567         trans = btrfs_start_transaction(root, 5);
6568         if (IS_ERR(trans))
6569                 return PTR_ERR(trans);
6570
6571         err = btrfs_find_free_ino(root, &objectid);
6572         if (err)
6573                 goto out_fail;
6574
6575         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6576                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6577                         S_IFDIR | mode, &index);
6578         if (IS_ERR(inode)) {
6579                 err = PTR_ERR(inode);
6580                 goto out_fail;
6581         }
6582
6583         drop_on_err = 1;
6584         /* these must be set before we unlock the inode */
6585         inode->i_op = &btrfs_dir_inode_operations;
6586         inode->i_fop = &btrfs_dir_file_operations;
6587
6588         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6589         if (err)
6590                 goto out_fail_inode;
6591
6592         btrfs_i_size_write(inode, 0);
6593         err = btrfs_update_inode(trans, root, inode);
6594         if (err)
6595                 goto out_fail_inode;
6596
6597         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
6598                              dentry->d_name.len, 0, index);
6599         if (err)
6600                 goto out_fail_inode;
6601
6602         d_instantiate(dentry, inode);
6603         /*
6604          * mkdir is special.  We're unlocking after we call d_instantiate
6605          * to avoid a race with nfsd calling d_instantiate.
6606          */
6607         unlock_new_inode(inode);
6608         drop_on_err = 0;
6609
6610 out_fail:
6611         btrfs_end_transaction(trans);
6612         if (drop_on_err) {
6613                 inode_dec_link_count(inode);
6614                 iput(inode);
6615         }
6616         btrfs_balance_delayed_items(fs_info);
6617         btrfs_btree_balance_dirty(fs_info);
6618         return err;
6619
6620 out_fail_inode:
6621         unlock_new_inode(inode);
6622         goto out_fail;
6623 }
6624
6625 /* Find next extent map of a given extent map, caller needs to ensure locks */
6626 static struct extent_map *next_extent_map(struct extent_map *em)
6627 {
6628         struct rb_node *next;
6629
6630         next = rb_next(&em->rb_node);
6631         if (!next)
6632                 return NULL;
6633         return container_of(next, struct extent_map, rb_node);
6634 }
6635
6636 static struct extent_map *prev_extent_map(struct extent_map *em)
6637 {
6638         struct rb_node *prev;
6639
6640         prev = rb_prev(&em->rb_node);
6641         if (!prev)
6642                 return NULL;
6643         return container_of(prev, struct extent_map, rb_node);
6644 }
6645
6646 /* helper for btfs_get_extent.  Given an existing extent in the tree,
6647  * the existing extent is the nearest extent to map_start,
6648  * and an extent that you want to insert, deal with overlap and insert
6649  * the best fitted new extent into the tree.
6650  */
6651 static int merge_extent_mapping(struct extent_map_tree *em_tree,
6652                                 struct extent_map *existing,
6653                                 struct extent_map *em,
6654                                 u64 map_start)
6655 {
6656         struct extent_map *prev;
6657         struct extent_map *next;
6658         u64 start;
6659         u64 end;
6660         u64 start_diff;
6661
6662         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
6663
6664         if (existing->start > map_start) {
6665                 next = existing;
6666                 prev = prev_extent_map(next);
6667         } else {
6668                 prev = existing;
6669                 next = next_extent_map(prev);
6670         }
6671
6672         start = prev ? extent_map_end(prev) : em->start;
6673         start = max_t(u64, start, em->start);
6674         end = next ? next->start : extent_map_end(em);
6675         end = min_t(u64, end, extent_map_end(em));
6676         start_diff = start - em->start;
6677         em->start = start;
6678         em->len = end - start;
6679         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
6680             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
6681                 em->block_start += start_diff;
6682                 em->block_len -= start_diff;
6683         }
6684         return add_extent_mapping(em_tree, em, 0);
6685 }
6686
6687 static noinline int uncompress_inline(struct btrfs_path *path,
6688                                       struct page *page,
6689                                       size_t pg_offset, u64 extent_offset,
6690                                       struct btrfs_file_extent_item *item)
6691 {
6692         int ret;
6693         struct extent_buffer *leaf = path->nodes[0];
6694         char *tmp;
6695         size_t max_size;
6696         unsigned long inline_size;
6697         unsigned long ptr;
6698         int compress_type;
6699
6700         WARN_ON(pg_offset != 0);
6701         compress_type = btrfs_file_extent_compression(leaf, item);
6702         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6703         inline_size = btrfs_file_extent_inline_item_len(leaf,
6704                                         btrfs_item_nr(path->slots[0]));
6705         tmp = kmalloc(inline_size, GFP_NOFS);
6706         if (!tmp)
6707                 return -ENOMEM;
6708         ptr = btrfs_file_extent_inline_start(item);
6709
6710         read_extent_buffer(leaf, tmp, ptr, inline_size);
6711
6712         max_size = min_t(unsigned long, PAGE_SIZE, max_size);
6713         ret = btrfs_decompress(compress_type, tmp, page,
6714                                extent_offset, inline_size, max_size);
6715         kfree(tmp);
6716         return ret;
6717 }
6718
6719 /*
6720  * a bit scary, this does extent mapping from logical file offset to the disk.
6721  * the ugly parts come from merging extents from the disk with the in-ram
6722  * representation.  This gets more complex because of the data=ordered code,
6723  * where the in-ram extents might be locked pending data=ordered completion.
6724  *
6725  * This also copies inline extents directly into the page.
6726  */
6727
6728 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
6729                                     size_t pg_offset, u64 start, u64 len,
6730                                     int create)
6731 {
6732         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
6733         int ret;
6734         int err = 0;
6735         u64 extent_start = 0;
6736         u64 extent_end = 0;
6737         u64 objectid = btrfs_ino(BTRFS_I(inode));
6738         u32 found_type;
6739         struct btrfs_path *path = NULL;
6740         struct btrfs_root *root = BTRFS_I(inode)->root;
6741         struct btrfs_file_extent_item *item;
6742         struct extent_buffer *leaf;
6743         struct btrfs_key found_key;
6744         struct extent_map *em = NULL;
6745         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
6746         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6747         struct btrfs_trans_handle *trans = NULL;
6748         const bool new_inline = !page || create;
6749
6750 again:
6751         read_lock(&em_tree->lock);
6752         em = lookup_extent_mapping(em_tree, start, len);
6753         if (em)
6754                 em->bdev = fs_info->fs_devices->latest_bdev;
6755         read_unlock(&em_tree->lock);
6756
6757         if (em) {
6758                 if (em->start > start || em->start + em->len <= start)
6759                         free_extent_map(em);
6760                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6761                         free_extent_map(em);
6762                 else
6763                         goto out;
6764         }
6765         em = alloc_extent_map();
6766         if (!em) {
6767                 err = -ENOMEM;
6768                 goto out;
6769         }
6770         em->bdev = fs_info->fs_devices->latest_bdev;
6771         em->start = EXTENT_MAP_HOLE;
6772         em->orig_start = EXTENT_MAP_HOLE;
6773         em->len = (u64)-1;
6774         em->block_len = (u64)-1;
6775
6776         if (!path) {
6777                 path = btrfs_alloc_path();
6778                 if (!path) {
6779                         err = -ENOMEM;
6780                         goto out;
6781                 }
6782                 /*
6783                  * Chances are we'll be called again, so go ahead and do
6784                  * readahead
6785                  */
6786                 path->reada = READA_FORWARD;
6787         }
6788
6789         ret = btrfs_lookup_file_extent(trans, root, path,
6790                                        objectid, start, trans != NULL);
6791         if (ret < 0) {
6792                 err = ret;
6793                 goto out;
6794         }
6795
6796         if (ret != 0) {
6797                 if (path->slots[0] == 0)
6798                         goto not_found;
6799                 path->slots[0]--;
6800         }
6801
6802         leaf = path->nodes[0];
6803         item = btrfs_item_ptr(leaf, path->slots[0],
6804                               struct btrfs_file_extent_item);
6805         /* are we inside the extent that was found? */
6806         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6807         found_type = found_key.type;
6808         if (found_key.objectid != objectid ||
6809             found_type != BTRFS_EXTENT_DATA_KEY) {
6810                 /*
6811                  * If we backup past the first extent we want to move forward
6812                  * and see if there is an extent in front of us, otherwise we'll
6813                  * say there is a hole for our whole search range which can
6814                  * cause problems.
6815                  */
6816                 extent_end = start;
6817                 goto next;
6818         }
6819
6820         found_type = btrfs_file_extent_type(leaf, item);
6821         extent_start = found_key.offset;
6822         if (found_type == BTRFS_FILE_EXTENT_REG ||
6823             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6824                 extent_end = extent_start +
6825                        btrfs_file_extent_num_bytes(leaf, item);
6826         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6827                 size_t size;
6828                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6829                 extent_end = ALIGN(extent_start + size,
6830                                    fs_info->sectorsize);
6831         }
6832 next:
6833         if (start >= extent_end) {
6834                 path->slots[0]++;
6835                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6836                         ret = btrfs_next_leaf(root, path);
6837                         if (ret < 0) {
6838                                 err = ret;
6839                                 goto out;
6840                         }
6841                         if (ret > 0)
6842                                 goto not_found;
6843                         leaf = path->nodes[0];
6844                 }
6845                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6846                 if (found_key.objectid != objectid ||
6847                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6848                         goto not_found;
6849                 if (start + len <= found_key.offset)
6850                         goto not_found;
6851                 if (start > found_key.offset)
6852                         goto next;
6853                 em->start = start;
6854                 em->orig_start = start;
6855                 em->len = found_key.offset - start;
6856                 goto not_found_em;
6857         }
6858
6859         btrfs_extent_item_to_extent_map(inode, path, item, new_inline, em);
6860
6861         if (found_type == BTRFS_FILE_EXTENT_REG ||
6862             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6863                 goto insert;
6864         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6865                 unsigned long ptr;
6866                 char *map;
6867                 size_t size;
6868                 size_t extent_offset;
6869                 size_t copy_size;
6870
6871                 if (new_inline)
6872                         goto out;
6873
6874                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6875                 extent_offset = page_offset(page) + pg_offset - extent_start;
6876                 copy_size = min_t(u64, PAGE_SIZE - pg_offset,
6877                                   size - extent_offset);
6878                 em->start = extent_start + extent_offset;
6879                 em->len = ALIGN(copy_size, fs_info->sectorsize);
6880                 em->orig_block_len = em->len;
6881                 em->orig_start = em->start;
6882                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6883                 if (create == 0 && !PageUptodate(page)) {
6884                         if (btrfs_file_extent_compression(leaf, item) !=
6885                             BTRFS_COMPRESS_NONE) {
6886                                 ret = uncompress_inline(path, page, pg_offset,
6887                                                         extent_offset, item);
6888                                 if (ret) {
6889                                         err = ret;
6890                                         goto out;
6891                                 }
6892                         } else {
6893                                 map = kmap(page);
6894                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6895                                                    copy_size);
6896                                 if (pg_offset + copy_size < PAGE_SIZE) {
6897                                         memset(map + pg_offset + copy_size, 0,
6898                                                PAGE_SIZE - pg_offset -
6899                                                copy_size);
6900                                 }
6901                                 kunmap(page);
6902                         }
6903                         flush_dcache_page(page);
6904                 } else if (create && PageUptodate(page)) {
6905                         BUG();
6906                         if (!trans) {
6907                                 kunmap(page);
6908                                 free_extent_map(em);
6909                                 em = NULL;
6910
6911                                 btrfs_release_path(path);
6912                                 trans = btrfs_join_transaction(root);
6913
6914                                 if (IS_ERR(trans))
6915                                         return ERR_CAST(trans);
6916                                 goto again;
6917                         }
6918                         map = kmap(page);
6919                         write_extent_buffer(leaf, map + pg_offset, ptr,
6920                                             copy_size);
6921                         kunmap(page);
6922                         btrfs_mark_buffer_dirty(leaf);
6923                 }
6924                 set_extent_uptodate(io_tree, em->start,
6925                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6926                 goto insert;
6927         }
6928 not_found:
6929         em->start = start;
6930         em->orig_start = start;
6931         em->len = len;
6932 not_found_em:
6933         em->block_start = EXTENT_MAP_HOLE;
6934         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
6935 insert:
6936         btrfs_release_path(path);
6937         if (em->start > start || extent_map_end(em) <= start) {
6938                 btrfs_err(fs_info,
6939                           "bad extent! em: [%llu %llu] passed [%llu %llu]",
6940                           em->start, em->len, start, len);
6941                 err = -EIO;
6942                 goto out;
6943         }
6944
6945         err = 0;
6946         write_lock(&em_tree->lock);
6947         ret = add_extent_mapping(em_tree, em, 0);
6948         /* it is possible that someone inserted the extent into the tree
6949          * while we had the lock dropped.  It is also possible that
6950          * an overlapping map exists in the tree
6951          */
6952         if (ret == -EEXIST) {
6953                 struct extent_map *existing;
6954
6955                 ret = 0;
6956
6957                 existing = search_extent_mapping(em_tree, start, len);
6958                 /*
6959                  * existing will always be non-NULL, since there must be
6960                  * extent causing the -EEXIST.
6961                  */
6962                 if (existing->start == em->start &&
6963                     extent_map_end(existing) >= extent_map_end(em) &&
6964                     em->block_start == existing->block_start) {
6965                         /*
6966                          * The existing extent map already encompasses the
6967                          * entire extent map we tried to add.
6968                          */
6969                         free_extent_map(em);
6970                         em = existing;
6971                         err = 0;
6972
6973                 } else if (start >= extent_map_end(existing) ||
6974                     start <= existing->start) {
6975                         /*
6976                          * The existing extent map is the one nearest to
6977                          * the [start, start + len) range which overlaps
6978                          */
6979                         err = merge_extent_mapping(em_tree, existing,
6980                                                    em, start);
6981                         free_extent_map(existing);
6982                         if (err) {
6983                                 free_extent_map(em);
6984                                 em = NULL;
6985                         }
6986                 } else {
6987                         free_extent_map(em);
6988                         em = existing;
6989                         err = 0;
6990                 }
6991         }
6992         write_unlock(&em_tree->lock);
6993 out:
6994
6995         trace_btrfs_get_extent(root, BTRFS_I(inode), em);
6996
6997         btrfs_free_path(path);
6998         if (trans) {
6999                 ret = btrfs_end_transaction(trans);
7000                 if (!err)
7001                         err = ret;
7002         }
7003         if (err) {
7004                 free_extent_map(em);
7005                 return ERR_PTR(err);
7006         }
7007         BUG_ON(!em); /* Error is always set */
7008         return em;
7009 }
7010
7011 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
7012                                            size_t pg_offset, u64 start, u64 len,
7013                                            int create)
7014 {
7015         struct extent_map *em;
7016         struct extent_map *hole_em = NULL;
7017         u64 range_start = start;
7018         u64 end;
7019         u64 found;
7020         u64 found_end;
7021         int err = 0;
7022
7023         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
7024         if (IS_ERR(em))
7025                 return em;
7026         if (em) {
7027                 /*
7028                  * if our em maps to
7029                  * -  a hole or
7030                  * -  a pre-alloc extent,
7031                  * there might actually be delalloc bytes behind it.
7032                  */
7033                 if (em->block_start != EXTENT_MAP_HOLE &&
7034                     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7035                         return em;
7036                 else
7037                         hole_em = em;
7038         }
7039
7040         /* check to see if we've wrapped (len == -1 or similar) */
7041         end = start + len;
7042         if (end < start)
7043                 end = (u64)-1;
7044         else
7045                 end -= 1;
7046
7047         em = NULL;
7048
7049         /* ok, we didn't find anything, lets look for delalloc */
7050         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
7051                                  end, len, EXTENT_DELALLOC, 1);
7052         found_end = range_start + found;
7053         if (found_end < range_start)
7054                 found_end = (u64)-1;
7055
7056         /*
7057          * we didn't find anything useful, return
7058          * the original results from get_extent()
7059          */
7060         if (range_start > end || found_end <= start) {
7061                 em = hole_em;
7062                 hole_em = NULL;
7063                 goto out;
7064         }
7065
7066         /* adjust the range_start to make sure it doesn't
7067          * go backwards from the start they passed in
7068          */
7069         range_start = max(start, range_start);
7070         found = found_end - range_start;
7071
7072         if (found > 0) {
7073                 u64 hole_start = start;
7074                 u64 hole_len = len;
7075
7076                 em = alloc_extent_map();
7077                 if (!em) {
7078                         err = -ENOMEM;
7079                         goto out;
7080                 }
7081                 /*
7082                  * when btrfs_get_extent can't find anything it
7083                  * returns one huge hole
7084                  *
7085                  * make sure what it found really fits our range, and
7086                  * adjust to make sure it is based on the start from
7087                  * the caller
7088                  */
7089                 if (hole_em) {
7090                         u64 calc_end = extent_map_end(hole_em);
7091
7092                         if (calc_end <= start || (hole_em->start > end)) {
7093                                 free_extent_map(hole_em);
7094                                 hole_em = NULL;
7095                         } else {
7096                                 hole_start = max(hole_em->start, start);
7097                                 hole_len = calc_end - hole_start;
7098                         }
7099                 }
7100                 em->bdev = NULL;
7101                 if (hole_em && range_start > hole_start) {
7102                         /* our hole starts before our delalloc, so we
7103                          * have to return just the parts of the hole
7104                          * that go until  the delalloc starts
7105                          */
7106                         em->len = min(hole_len,
7107                                       range_start - hole_start);
7108                         em->start = hole_start;
7109                         em->orig_start = hole_start;
7110                         /*
7111                          * don't adjust block start at all,
7112                          * it is fixed at EXTENT_MAP_HOLE
7113                          */
7114                         em->block_start = hole_em->block_start;
7115                         em->block_len = hole_len;
7116                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
7117                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
7118                 } else {
7119                         em->start = range_start;
7120                         em->len = found;
7121                         em->orig_start = range_start;
7122                         em->block_start = EXTENT_MAP_DELALLOC;
7123                         em->block_len = found;
7124                 }
7125         } else if (hole_em) {
7126                 return hole_em;
7127         }
7128 out:
7129
7130         free_extent_map(hole_em);
7131         if (err) {
7132                 free_extent_map(em);
7133                 return ERR_PTR(err);
7134         }
7135         return em;
7136 }
7137
7138 static struct extent_map *btrfs_create_dio_extent(struct inode *inode,
7139                                                   const u64 start,
7140                                                   const u64 len,
7141                                                   const u64 orig_start,
7142                                                   const u64 block_start,
7143                                                   const u64 block_len,
7144                                                   const u64 orig_block_len,
7145                                                   const u64 ram_bytes,
7146                                                   const int type)
7147 {
7148         struct extent_map *em = NULL;
7149         int ret;
7150
7151         if (type != BTRFS_ORDERED_NOCOW) {
7152                 em = create_io_em(inode, start, len, orig_start,
7153                                   block_start, block_len, orig_block_len,
7154                                   ram_bytes,
7155                                   BTRFS_COMPRESS_NONE, /* compress_type */
7156                                   type);
7157                 if (IS_ERR(em))
7158                         goto out;
7159         }
7160         ret = btrfs_add_ordered_extent_dio(inode, start, block_start,
7161                                            len, block_len, type);
7162         if (ret) {
7163                 if (em) {
7164                         free_extent_map(em);
7165                         btrfs_drop_extent_cache(inode, start,
7166                                                 start + len - 1, 0);
7167                 }
7168                 em = ERR_PTR(ret);
7169         }
7170  out:
7171
7172         return em;
7173 }
7174
7175 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
7176                                                   u64 start, u64 len)
7177 {
7178         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7179         struct btrfs_root *root = BTRFS_I(inode)->root;
7180         struct extent_map *em;
7181         struct btrfs_key ins;
7182         u64 alloc_hint;
7183         int ret;
7184
7185         alloc_hint = get_extent_allocation_hint(inode, start, len);
7186         ret = btrfs_reserve_extent(root, len, len, fs_info->sectorsize,
7187                                    0, alloc_hint, &ins, 1, 1);
7188         if (ret)
7189                 return ERR_PTR(ret);
7190
7191         em = btrfs_create_dio_extent(inode, start, ins.offset, start,
7192                                      ins.objectid, ins.offset, ins.offset,
7193                                      ins.offset, BTRFS_ORDERED_REGULAR);
7194         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
7195         if (IS_ERR(em))
7196                 btrfs_free_reserved_extent(fs_info, ins.objectid,
7197                                            ins.offset, 1);
7198
7199         return em;
7200 }
7201
7202 /*
7203  * returns 1 when the nocow is safe, < 1 on error, 0 if the
7204  * block must be cow'd
7205  */
7206 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
7207                               u64 *orig_start, u64 *orig_block_len,
7208                               u64 *ram_bytes)
7209 {
7210         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7211         struct btrfs_path *path;
7212         int ret;
7213         struct extent_buffer *leaf;
7214         struct btrfs_root *root = BTRFS_I(inode)->root;
7215         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7216         struct btrfs_file_extent_item *fi;
7217         struct btrfs_key key;
7218         u64 disk_bytenr;
7219         u64 backref_offset;
7220         u64 extent_end;
7221         u64 num_bytes;
7222         int slot;
7223         int found_type;
7224         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
7225
7226         path = btrfs_alloc_path();
7227         if (!path)
7228                 return -ENOMEM;
7229
7230         ret = btrfs_lookup_file_extent(NULL, root, path,
7231                         btrfs_ino(BTRFS_I(inode)), offset, 0);
7232         if (ret < 0)
7233                 goto out;
7234
7235         slot = path->slots[0];
7236         if (ret == 1) {
7237                 if (slot == 0) {
7238                         /* can't find the item, must cow */
7239                         ret = 0;
7240                         goto out;
7241                 }
7242                 slot--;
7243         }
7244         ret = 0;
7245         leaf = path->nodes[0];
7246         btrfs_item_key_to_cpu(leaf, &key, slot);
7247         if (key.objectid != btrfs_ino(BTRFS_I(inode)) ||
7248             key.type != BTRFS_EXTENT_DATA_KEY) {
7249                 /* not our file or wrong item type, must cow */
7250                 goto out;
7251         }
7252
7253         if (key.offset > offset) {
7254                 /* Wrong offset, must cow */
7255                 goto out;
7256         }
7257
7258         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
7259         found_type = btrfs_file_extent_type(leaf, fi);
7260         if (found_type != BTRFS_FILE_EXTENT_REG &&
7261             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
7262                 /* not a regular extent, must cow */
7263                 goto out;
7264         }
7265
7266         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
7267                 goto out;
7268
7269         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
7270         if (extent_end <= offset)
7271                 goto out;
7272
7273         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
7274         if (disk_bytenr == 0)
7275                 goto out;
7276
7277         if (btrfs_file_extent_compression(leaf, fi) ||
7278             btrfs_file_extent_encryption(leaf, fi) ||
7279             btrfs_file_extent_other_encoding(leaf, fi))
7280                 goto out;
7281
7282         backref_offset = btrfs_file_extent_offset(leaf, fi);
7283
7284         if (orig_start) {
7285                 *orig_start = key.offset - backref_offset;
7286                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
7287                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
7288         }
7289
7290         if (btrfs_extent_readonly(fs_info, disk_bytenr))
7291                 goto out;
7292
7293         num_bytes = min(offset + *len, extent_end) - offset;
7294         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
7295                 u64 range_end;
7296
7297                 range_end = round_up(offset + num_bytes,
7298                                      root->fs_info->sectorsize) - 1;
7299                 ret = test_range_bit(io_tree, offset, range_end,
7300                                      EXTENT_DELALLOC, 0, NULL);
7301                 if (ret) {
7302                         ret = -EAGAIN;
7303                         goto out;
7304                 }
7305         }
7306
7307         btrfs_release_path(path);
7308
7309         /*
7310          * look for other files referencing this extent, if we
7311          * find any we must cow
7312          */
7313
7314         ret = btrfs_cross_ref_exist(root, btrfs_ino(BTRFS_I(inode)),
7315                                     key.offset - backref_offset, disk_bytenr);
7316         if (ret) {
7317                 ret = 0;
7318                 goto out;
7319         }
7320
7321         /*
7322          * adjust disk_bytenr and num_bytes to cover just the bytes
7323          * in this extent we are about to write.  If there
7324          * are any csums in that range we have to cow in order
7325          * to keep the csums correct
7326          */
7327         disk_bytenr += backref_offset;
7328         disk_bytenr += offset - key.offset;
7329         if (csum_exist_in_range(fs_info, disk_bytenr, num_bytes))
7330                 goto out;
7331         /*
7332          * all of the above have passed, it is safe to overwrite this extent
7333          * without cow
7334          */
7335         *len = num_bytes;
7336         ret = 1;
7337 out:
7338         btrfs_free_path(path);
7339         return ret;
7340 }
7341
7342 bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end)
7343 {
7344         struct radix_tree_root *root = &inode->i_mapping->page_tree;
7345         int found = false;
7346         void **pagep = NULL;
7347         struct page *page = NULL;
7348         int start_idx;
7349         int end_idx;
7350
7351         start_idx = start >> PAGE_SHIFT;
7352
7353         /*
7354          * end is the last byte in the last page.  end == start is legal
7355          */
7356         end_idx = end >> PAGE_SHIFT;
7357
7358         rcu_read_lock();
7359
7360         /* Most of the code in this while loop is lifted from
7361          * find_get_page.  It's been modified to begin searching from a
7362          * page and return just the first page found in that range.  If the
7363          * found idx is less than or equal to the end idx then we know that
7364          * a page exists.  If no pages are found or if those pages are
7365          * outside of the range then we're fine (yay!) */
7366         while (page == NULL &&
7367                radix_tree_gang_lookup_slot(root, &pagep, NULL, start_idx, 1)) {
7368                 page = radix_tree_deref_slot(pagep);
7369                 if (unlikely(!page))
7370                         break;
7371
7372                 if (radix_tree_exception(page)) {
7373                         if (radix_tree_deref_retry(page)) {
7374                                 page = NULL;
7375                                 continue;
7376                         }
7377                         /*
7378                          * Otherwise, shmem/tmpfs must be storing a swap entry
7379                          * here as an exceptional entry: so return it without
7380                          * attempting to raise page count.
7381                          */
7382                         page = NULL;
7383                         break; /* TODO: Is this relevant for this use case? */
7384                 }
7385
7386                 if (!page_cache_get_speculative(page)) {
7387                         page = NULL;
7388                         continue;
7389                 }
7390
7391                 /*
7392                  * Has the page moved?
7393                  * This is part of the lockless pagecache protocol. See
7394                  * include/linux/pagemap.h for details.
7395                  */
7396                 if (unlikely(page != *pagep)) {
7397                         put_page(page);
7398                         page = NULL;
7399                 }
7400         }
7401
7402         if (page) {
7403                 if (page->index <= end_idx)
7404                         found = true;
7405                 put_page(page);
7406         }
7407
7408         rcu_read_unlock();
7409         return found;
7410 }
7411
7412 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
7413                               struct extent_state **cached_state, int writing)
7414 {
7415         struct btrfs_ordered_extent *ordered;
7416         int ret = 0;
7417
7418         while (1) {
7419                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7420                                  cached_state);
7421                 /*
7422                  * We're concerned with the entire range that we're going to be
7423                  * doing DIO to, so we need to make sure there's no ordered
7424                  * extents in this range.
7425                  */
7426                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
7427                                                      lockend - lockstart + 1);
7428
7429                 /*
7430                  * We need to make sure there are no buffered pages in this
7431                  * range either, we could have raced between the invalidate in
7432                  * generic_file_direct_write and locking the extent.  The
7433                  * invalidate needs to happen so that reads after a write do not
7434                  * get stale data.
7435                  */
7436                 if (!ordered &&
7437                     (!writing ||
7438                      !btrfs_page_exists_in_range(inode, lockstart, lockend)))
7439                         break;
7440
7441                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7442                                      cached_state, GFP_NOFS);
7443
7444                 if (ordered) {
7445                         /*
7446                          * If we are doing a DIO read and the ordered extent we
7447                          * found is for a buffered write, we can not wait for it
7448                          * to complete and retry, because if we do so we can
7449                          * deadlock with concurrent buffered writes on page
7450                          * locks. This happens only if our DIO read covers more
7451                          * than one extent map, if at this point has already
7452                          * created an ordered extent for a previous extent map
7453                          * and locked its range in the inode's io tree, and a
7454                          * concurrent write against that previous extent map's
7455                          * range and this range started (we unlock the ranges
7456                          * in the io tree only when the bios complete and
7457                          * buffered writes always lock pages before attempting
7458                          * to lock range in the io tree).
7459                          */
7460                         if (writing ||
7461                             test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags))
7462                                 btrfs_start_ordered_extent(inode, ordered, 1);
7463                         else
7464                                 ret = -ENOTBLK;
7465                         btrfs_put_ordered_extent(ordered);
7466                 } else {
7467                         /*
7468                          * We could trigger writeback for this range (and wait
7469                          * for it to complete) and then invalidate the pages for
7470                          * this range (through invalidate_inode_pages2_range()),
7471                          * but that can lead us to a deadlock with a concurrent
7472                          * call to readpages() (a buffered read or a defrag call
7473                          * triggered a readahead) on a page lock due to an
7474                          * ordered dio extent we created before but did not have
7475                          * yet a corresponding bio submitted (whence it can not
7476                          * complete), which makes readpages() wait for that
7477                          * ordered extent to complete while holding a lock on
7478                          * that page.
7479                          */
7480                         ret = -ENOTBLK;
7481                 }
7482
7483                 if (ret)
7484                         break;
7485
7486                 cond_resched();
7487         }
7488
7489         return ret;
7490 }
7491
7492 /* The callers of this must take lock_extent() */
7493 static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len,
7494                                        u64 orig_start, u64 block_start,
7495                                        u64 block_len, u64 orig_block_len,
7496                                        u64 ram_bytes, int compress_type,
7497                                        int type)
7498 {
7499         struct extent_map_tree *em_tree;
7500         struct extent_map *em;
7501         struct btrfs_root *root = BTRFS_I(inode)->root;
7502         int ret;
7503
7504         ASSERT(type == BTRFS_ORDERED_PREALLOC ||
7505                type == BTRFS_ORDERED_COMPRESSED ||
7506                type == BTRFS_ORDERED_NOCOW ||
7507                type == BTRFS_ORDERED_REGULAR);
7508
7509         em_tree = &BTRFS_I(inode)->extent_tree;
7510         em = alloc_extent_map();
7511         if (!em)
7512                 return ERR_PTR(-ENOMEM);
7513
7514         em->start = start;
7515         em->orig_start = orig_start;
7516         em->len = len;
7517         em->block_len = block_len;
7518         em->block_start = block_start;
7519         em->bdev = root->fs_info->fs_devices->latest_bdev;
7520         em->orig_block_len = orig_block_len;
7521         em->ram_bytes = ram_bytes;
7522         em->generation = -1;
7523         set_bit(EXTENT_FLAG_PINNED, &em->flags);
7524         if (type == BTRFS_ORDERED_PREALLOC) {
7525                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
7526         } else if (type == BTRFS_ORDERED_COMPRESSED) {
7527                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
7528                 em->compress_type = compress_type;
7529         }
7530
7531         do {
7532                 btrfs_drop_extent_cache(inode, em->start,
7533                                 em->start + em->len - 1, 0);
7534                 write_lock(&em_tree->lock);
7535                 ret = add_extent_mapping(em_tree, em, 1);
7536                 write_unlock(&em_tree->lock);
7537                 /*
7538                  * The caller has taken lock_extent(), who could race with us
7539                  * to add em?
7540                  */
7541         } while (ret == -EEXIST);
7542
7543         if (ret) {
7544                 free_extent_map(em);
7545                 return ERR_PTR(ret);
7546         }
7547
7548         /* em got 2 refs now, callers needs to do free_extent_map once. */
7549         return em;
7550 }
7551
7552 static void adjust_dio_outstanding_extents(struct inode *inode,
7553                                            struct btrfs_dio_data *dio_data,
7554                                            const u64 len)
7555 {
7556         unsigned num_extents = count_max_extents(len);
7557
7558         /*
7559          * If we have an outstanding_extents count still set then we're
7560          * within our reservation, otherwise we need to adjust our inode
7561          * counter appropriately.
7562          */
7563         if (dio_data->outstanding_extents >= num_extents) {
7564                 dio_data->outstanding_extents -= num_extents;
7565         } else {
7566                 /*
7567                  * If dio write length has been split due to no large enough
7568                  * contiguous space, we need to compensate our inode counter
7569                  * appropriately.
7570                  */
7571                 u64 num_needed = num_extents - dio_data->outstanding_extents;
7572
7573                 spin_lock(&BTRFS_I(inode)->lock);
7574                 BTRFS_I(inode)->outstanding_extents += num_needed;
7575                 spin_unlock(&BTRFS_I(inode)->lock);
7576         }
7577 }
7578
7579 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
7580                                    struct buffer_head *bh_result, int create)
7581 {
7582         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7583         struct extent_map *em;
7584         struct extent_state *cached_state = NULL;
7585         struct btrfs_dio_data *dio_data = NULL;
7586         u64 start = iblock << inode->i_blkbits;
7587         u64 lockstart, lockend;
7588         u64 len = bh_result->b_size;
7589         int unlock_bits = EXTENT_LOCKED;
7590         int ret = 0;
7591
7592         if (create)
7593                 unlock_bits |= EXTENT_DIRTY;
7594         else
7595                 len = min_t(u64, len, fs_info->sectorsize);
7596
7597         lockstart = start;
7598         lockend = start + len - 1;
7599
7600         if (current->journal_info) {
7601                 /*
7602                  * Need to pull our outstanding extents and set journal_info to NULL so
7603                  * that anything that needs to check if there's a transaction doesn't get
7604                  * confused.
7605                  */
7606                 dio_data = current->journal_info;
7607                 current->journal_info = NULL;
7608         }
7609
7610         /*
7611          * If this errors out it's because we couldn't invalidate pagecache for
7612          * this range and we need to fallback to buffered.
7613          */
7614         if (lock_extent_direct(inode, lockstart, lockend, &cached_state,
7615                                create)) {
7616                 ret = -ENOTBLK;
7617                 goto err;
7618         }
7619
7620         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
7621         if (IS_ERR(em)) {
7622                 ret = PTR_ERR(em);
7623                 goto unlock_err;
7624         }
7625
7626         /*
7627          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
7628          * io.  INLINE is special, and we could probably kludge it in here, but
7629          * it's still buffered so for safety lets just fall back to the generic
7630          * buffered path.
7631          *
7632          * For COMPRESSED we _have_ to read the entire extent in so we can
7633          * decompress it, so there will be buffering required no matter what we
7634          * do, so go ahead and fallback to buffered.
7635          *
7636          * We return -ENOTBLK because that's what makes DIO go ahead and go back
7637          * to buffered IO.  Don't blame me, this is the price we pay for using
7638          * the generic code.
7639          */
7640         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
7641             em->block_start == EXTENT_MAP_INLINE) {
7642                 free_extent_map(em);
7643                 ret = -ENOTBLK;
7644                 goto unlock_err;
7645         }
7646
7647         /* Just a good old fashioned hole, return */
7648         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
7649                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
7650                 free_extent_map(em);
7651                 goto unlock_err;
7652         }
7653
7654         /*
7655          * We don't allocate a new extent in the following cases
7656          *
7657          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
7658          * existing extent.
7659          * 2) The extent is marked as PREALLOC.  We're good to go here and can
7660          * just use the extent.
7661          *
7662          */
7663         if (!create) {
7664                 len = min(len, em->len - (start - em->start));
7665                 lockstart = start + len;
7666                 goto unlock;
7667         }
7668
7669         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
7670             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
7671              em->block_start != EXTENT_MAP_HOLE)) {
7672                 int type;
7673                 u64 block_start, orig_start, orig_block_len, ram_bytes;
7674
7675                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7676                         type = BTRFS_ORDERED_PREALLOC;
7677                 else
7678                         type = BTRFS_ORDERED_NOCOW;
7679                 len = min(len, em->len - (start - em->start));
7680                 block_start = em->block_start + (start - em->start);
7681
7682                 if (can_nocow_extent(inode, start, &len, &orig_start,
7683                                      &orig_block_len, &ram_bytes) == 1 &&
7684                     btrfs_inc_nocow_writers(fs_info, block_start)) {
7685                         struct extent_map *em2;
7686
7687                         em2 = btrfs_create_dio_extent(inode, start, len,
7688                                                       orig_start, block_start,
7689                                                       len, orig_block_len,
7690                                                       ram_bytes, type);
7691                         btrfs_dec_nocow_writers(fs_info, block_start);
7692                         if (type == BTRFS_ORDERED_PREALLOC) {
7693                                 free_extent_map(em);
7694                                 em = em2;
7695                         }
7696                         if (em2 && IS_ERR(em2)) {
7697                                 ret = PTR_ERR(em2);
7698                                 goto unlock_err;
7699                         }
7700                         /*
7701                          * For inode marked NODATACOW or extent marked PREALLOC,
7702                          * use the existing or preallocated extent, so does not
7703                          * need to adjust btrfs_space_info's bytes_may_use.
7704                          */
7705                         btrfs_free_reserved_data_space_noquota(inode,
7706                                         start, len);
7707                         goto unlock;
7708                 }
7709         }
7710
7711         /*
7712          * this will cow the extent, reset the len in case we changed
7713          * it above
7714          */
7715         len = bh_result->b_size;
7716         free_extent_map(em);
7717         em = btrfs_new_extent_direct(inode, start, len);
7718         if (IS_ERR(em)) {
7719                 ret = PTR_ERR(em);
7720                 goto unlock_err;
7721         }
7722         len = min(len, em->len - (start - em->start));
7723 unlock:
7724         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7725                 inode->i_blkbits;
7726         bh_result->b_size = len;
7727         bh_result->b_bdev = em->bdev;
7728         set_buffer_mapped(bh_result);
7729         if (create) {
7730                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7731                         set_buffer_new(bh_result);
7732
7733                 /*
7734                  * Need to update the i_size under the extent lock so buffered
7735                  * readers will get the updated i_size when we unlock.
7736                  */
7737                 if (!dio_data->overwrite && start + len > i_size_read(inode))
7738                         i_size_write(inode, start + len);
7739
7740                 adjust_dio_outstanding_extents(inode, dio_data, len);
7741                 WARN_ON(dio_data->reserve < len);
7742                 dio_data->reserve -= len;
7743                 dio_data->unsubmitted_oe_range_end = start + len;
7744                 current->journal_info = dio_data;
7745         }
7746
7747         /*
7748          * In the case of write we need to clear and unlock the entire range,
7749          * in the case of read we need to unlock only the end area that we
7750          * aren't using if there is any left over space.
7751          */
7752         if (lockstart < lockend) {
7753                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7754                                  lockend, unlock_bits, 1, 0,
7755                                  &cached_state, GFP_NOFS);
7756         } else {
7757                 free_extent_state(cached_state);
7758         }
7759
7760         free_extent_map(em);
7761
7762         return 0;
7763
7764 unlock_err:
7765         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7766                          unlock_bits, 1, 0, &cached_state, GFP_NOFS);
7767 err:
7768         if (dio_data)
7769                 current->journal_info = dio_data;
7770         /*
7771          * Compensate the delalloc release we do in btrfs_direct_IO() when we
7772          * write less data then expected, so that we don't underflow our inode's
7773          * outstanding extents counter.
7774          */
7775         if (create && dio_data)
7776                 adjust_dio_outstanding_extents(inode, dio_data, len);
7777
7778         return ret;
7779 }
7780
7781 static inline int submit_dio_repair_bio(struct inode *inode, struct bio *bio,
7782                                         int mirror_num)
7783 {
7784         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7785         int ret;
7786
7787         BUG_ON(bio_op(bio) == REQ_OP_WRITE);
7788
7789         bio_get(bio);
7790
7791         ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DIO_REPAIR);
7792         if (ret)
7793                 goto err;
7794
7795         ret = btrfs_map_bio(fs_info, bio, mirror_num, 0);
7796 err:
7797         bio_put(bio);
7798         return ret;
7799 }
7800
7801 static int btrfs_check_dio_repairable(struct inode *inode,
7802                                       struct bio *failed_bio,
7803                                       struct io_failure_record *failrec,
7804                                       int failed_mirror)
7805 {
7806         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7807         int num_copies;
7808
7809         num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
7810         if (num_copies == 1) {
7811                 /*
7812                  * we only have a single copy of the data, so don't bother with
7813                  * all the retry and error correction code that follows. no
7814                  * matter what the error is, it is very likely to persist.
7815                  */
7816                 btrfs_debug(fs_info,
7817                         "Check DIO Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
7818                         num_copies, failrec->this_mirror, failed_mirror);
7819                 return 0;
7820         }
7821
7822         failrec->failed_mirror = failed_mirror;
7823         failrec->this_mirror++;
7824         if (failrec->this_mirror == failed_mirror)
7825                 failrec->this_mirror++;
7826
7827         if (failrec->this_mirror > num_copies) {
7828                 btrfs_debug(fs_info,
7829                         "Check DIO Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
7830                         num_copies, failrec->this_mirror, failed_mirror);
7831                 return 0;
7832         }
7833
7834         return 1;
7835 }
7836
7837 static int dio_read_error(struct inode *inode, struct bio *failed_bio,
7838                         struct page *page, unsigned int pgoff,
7839                         u64 start, u64 end, int failed_mirror,
7840                         bio_end_io_t *repair_endio, void *repair_arg)
7841 {
7842         struct io_failure_record *failrec;
7843         struct bio *bio;
7844         int isector;
7845         int read_mode = 0;
7846         int ret;
7847
7848         BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
7849
7850         ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
7851         if (ret)
7852                 return ret;
7853
7854         ret = btrfs_check_dio_repairable(inode, failed_bio, failrec,
7855                                          failed_mirror);
7856         if (!ret) {
7857                 free_io_failure(inode, failrec);
7858                 return -EIO;
7859         }
7860
7861         if ((failed_bio->bi_vcnt > 1)
7862                 || (failed_bio->bi_io_vec->bv_len
7863                         > btrfs_inode_sectorsize(inode)))
7864                 read_mode |= REQ_FAILFAST_DEV;
7865
7866         isector = start - btrfs_io_bio(failed_bio)->logical;
7867         isector >>= inode->i_sb->s_blocksize_bits;
7868         bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
7869                                 pgoff, isector, repair_endio, repair_arg);
7870         if (!bio) {
7871                 free_io_failure(inode, failrec);
7872                 return -EIO;
7873         }
7874         bio_set_op_attrs(bio, REQ_OP_READ, read_mode);
7875
7876         btrfs_debug(BTRFS_I(inode)->root->fs_info,
7877                     "Repair DIO Read Error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d\n",
7878                     read_mode, failrec->this_mirror, failrec->in_validation);
7879
7880         ret = submit_dio_repair_bio(inode, bio, failrec->this_mirror);
7881         if (ret) {
7882                 free_io_failure(inode, failrec);
7883                 bio_put(bio);
7884         }
7885
7886         return ret;
7887 }
7888
7889 struct btrfs_retry_complete {
7890         struct completion done;
7891         struct inode *inode;
7892         u64 start;
7893         int uptodate;
7894 };
7895
7896 static void btrfs_retry_endio_nocsum(struct bio *bio)
7897 {
7898         struct btrfs_retry_complete *done = bio->bi_private;
7899         struct inode *inode;
7900         struct bio_vec *bvec;
7901         int i;
7902
7903         if (bio->bi_error)
7904                 goto end;
7905
7906         ASSERT(bio->bi_vcnt == 1);
7907         inode = bio->bi_io_vec->bv_page->mapping->host;
7908         ASSERT(bio->bi_io_vec->bv_len == btrfs_inode_sectorsize(inode));
7909
7910         done->uptodate = 1;
7911         bio_for_each_segment_all(bvec, bio, i)
7912                 clean_io_failure(done->inode, done->start, bvec->bv_page, 0);
7913 end:
7914         complete(&done->done);
7915         bio_put(bio);
7916 }
7917
7918 static int __btrfs_correct_data_nocsum(struct inode *inode,
7919                                        struct btrfs_io_bio *io_bio)
7920 {
7921         struct btrfs_fs_info *fs_info;
7922         struct bio_vec *bvec;
7923         struct btrfs_retry_complete done;
7924         u64 start;
7925         unsigned int pgoff;
7926         u32 sectorsize;
7927         int nr_sectors;
7928         int i;
7929         int ret;
7930
7931         fs_info = BTRFS_I(inode)->root->fs_info;
7932         sectorsize = fs_info->sectorsize;
7933
7934         start = io_bio->logical;
7935         done.inode = inode;
7936
7937         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
7938                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
7939                 pgoff = bvec->bv_offset;
7940
7941 next_block_or_try_again:
7942                 done.uptodate = 0;
7943                 done.start = start;
7944                 init_completion(&done.done);
7945
7946                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page,
7947                                 pgoff, start, start + sectorsize - 1,
7948                                 io_bio->mirror_num,
7949                                 btrfs_retry_endio_nocsum, &done);
7950                 if (ret)
7951                         return ret;
7952
7953                 wait_for_completion(&done.done);
7954
7955                 if (!done.uptodate) {
7956                         /* We might have another mirror, so try again */
7957                         goto next_block_or_try_again;
7958                 }
7959
7960                 start += sectorsize;
7961
7962                 if (nr_sectors--) {
7963                         pgoff += sectorsize;
7964                         goto next_block_or_try_again;
7965                 }
7966         }
7967
7968         return 0;
7969 }
7970
7971 static void btrfs_retry_endio(struct bio *bio)
7972 {
7973         struct btrfs_retry_complete *done = bio->bi_private;
7974         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7975         struct inode *inode;
7976         struct bio_vec *bvec;
7977         u64 start;
7978         int uptodate;
7979         int ret;
7980         int i;
7981
7982         if (bio->bi_error)
7983                 goto end;
7984
7985         uptodate = 1;
7986
7987         start = done->start;
7988
7989         ASSERT(bio->bi_vcnt == 1);
7990         inode = bio->bi_io_vec->bv_page->mapping->host;
7991         ASSERT(bio->bi_io_vec->bv_len == btrfs_inode_sectorsize(inode));
7992
7993         bio_for_each_segment_all(bvec, bio, i) {
7994                 ret = __readpage_endio_check(done->inode, io_bio, i,
7995                                         bvec->bv_page, bvec->bv_offset,
7996                                         done->start, bvec->bv_len);
7997                 if (!ret)
7998                         clean_io_failure(done->inode, done->start,
7999                                         bvec->bv_page, bvec->bv_offset);
8000                 else
8001                         uptodate = 0;
8002         }
8003
8004         done->uptodate = uptodate;
8005 end:
8006         complete(&done->done);
8007         bio_put(bio);
8008 }
8009
8010 static int __btrfs_subio_endio_read(struct inode *inode,
8011                                     struct btrfs_io_bio *io_bio, int err)
8012 {
8013         struct btrfs_fs_info *fs_info;
8014         struct bio_vec *bvec;
8015         struct btrfs_retry_complete done;
8016         u64 start;
8017         u64 offset = 0;
8018         u32 sectorsize;
8019         int nr_sectors;
8020         unsigned int pgoff;
8021         int csum_pos;
8022         int i;
8023         int ret;
8024
8025         fs_info = BTRFS_I(inode)->root->fs_info;
8026         sectorsize = fs_info->sectorsize;
8027
8028         err = 0;
8029         start = io_bio->logical;
8030         done.inode = inode;
8031
8032         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
8033                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
8034
8035                 pgoff = bvec->bv_offset;
8036 next_block:
8037                 csum_pos = BTRFS_BYTES_TO_BLKS(fs_info, offset);
8038                 ret = __readpage_endio_check(inode, io_bio, csum_pos,
8039                                         bvec->bv_page, pgoff, start,
8040                                         sectorsize);
8041                 if (likely(!ret))
8042                         goto next;
8043 try_again:
8044                 done.uptodate = 0;
8045                 done.start = start;
8046                 init_completion(&done.done);
8047
8048                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page,
8049                                 pgoff, start, start + sectorsize - 1,
8050                                 io_bio->mirror_num,
8051                                 btrfs_retry_endio, &done);
8052                 if (ret) {
8053                         err = ret;
8054                         goto next;
8055                 }
8056
8057                 wait_for_completion(&done.done);
8058
8059                 if (!done.uptodate) {
8060                         /* We might have another mirror, so try again */
8061                         goto try_again;
8062                 }
8063 next:
8064                 offset += sectorsize;
8065                 start += sectorsize;
8066
8067                 ASSERT(nr_sectors);
8068
8069                 if (--nr_sectors) {
8070                         pgoff += sectorsize;
8071                         goto next_block;
8072                 }
8073         }
8074
8075         return err;
8076 }
8077
8078 static int btrfs_subio_endio_read(struct inode *inode,
8079                                   struct btrfs_io_bio *io_bio, int err)
8080 {
8081         bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
8082
8083         if (skip_csum) {
8084                 if (unlikely(err))
8085                         return __btrfs_correct_data_nocsum(inode, io_bio);
8086                 else
8087                         return 0;
8088         } else {
8089                 return __btrfs_subio_endio_read(inode, io_bio, err);
8090         }
8091 }
8092
8093 static void btrfs_endio_direct_read(struct bio *bio)
8094 {
8095         struct btrfs_dio_private *dip = bio->bi_private;
8096         struct inode *inode = dip->inode;
8097         struct bio *dio_bio;
8098         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8099         int err = bio->bi_error;
8100
8101         if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED)
8102                 err = btrfs_subio_endio_read(inode, io_bio, err);
8103
8104         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
8105                       dip->logical_offset + dip->bytes - 1);
8106         dio_bio = dip->dio_bio;
8107
8108         kfree(dip);
8109
8110         dio_bio->bi_error = bio->bi_error;
8111         dio_end_io(dio_bio, bio->bi_error);
8112
8113         if (io_bio->end_io)
8114                 io_bio->end_io(io_bio, err);
8115         bio_put(bio);
8116 }
8117
8118 static void btrfs_endio_direct_write_update_ordered(struct inode *inode,
8119                                                     const u64 offset,
8120                                                     const u64 bytes,
8121                                                     const int uptodate)
8122 {
8123         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8124         struct btrfs_ordered_extent *ordered = NULL;
8125         u64 ordered_offset = offset;
8126         u64 ordered_bytes = bytes;
8127         int ret;
8128
8129 again:
8130         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
8131                                                    &ordered_offset,
8132                                                    ordered_bytes,
8133                                                    uptodate);
8134         if (!ret)
8135                 goto out_test;
8136
8137         btrfs_init_work(&ordered->work, btrfs_endio_write_helper,
8138                         finish_ordered_fn, NULL, NULL);
8139         btrfs_queue_work(fs_info->endio_write_workers, &ordered->work);
8140 out_test:
8141         /*
8142          * our bio might span multiple ordered extents.  If we haven't
8143          * completed the accounting for the whole dio, go back and try again
8144          */
8145         if (ordered_offset < offset + bytes) {
8146                 ordered_bytes = offset + bytes - ordered_offset;
8147                 ordered = NULL;
8148                 goto again;
8149         }
8150 }
8151
8152 static void btrfs_endio_direct_write(struct bio *bio)
8153 {
8154         struct btrfs_dio_private *dip = bio->bi_private;
8155         struct bio *dio_bio = dip->dio_bio;
8156
8157         btrfs_endio_direct_write_update_ordered(dip->inode,
8158                                                 dip->logical_offset,
8159                                                 dip->bytes,
8160                                                 !bio->bi_error);
8161
8162         kfree(dip);
8163
8164         dio_bio->bi_error = bio->bi_error;
8165         dio_end_io(dio_bio, bio->bi_error);
8166         bio_put(bio);
8167 }
8168
8169 static int __btrfs_submit_bio_start_direct_io(struct inode *inode,
8170                                     struct bio *bio, int mirror_num,
8171                                     unsigned long bio_flags, u64 offset)
8172 {
8173         int ret;
8174         ret = btrfs_csum_one_bio(inode, bio, offset, 1);
8175         BUG_ON(ret); /* -ENOMEM */
8176         return 0;
8177 }
8178
8179 static void btrfs_end_dio_bio(struct bio *bio)
8180 {
8181         struct btrfs_dio_private *dip = bio->bi_private;
8182         int err = bio->bi_error;
8183
8184         if (err)
8185                 btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
8186                            "direct IO failed ino %llu rw %d,%u sector %#Lx len %u err no %d",
8187                            btrfs_ino(BTRFS_I(dip->inode)), bio_op(bio),
8188                            bio->bi_opf,
8189                            (unsigned long long)bio->bi_iter.bi_sector,
8190                            bio->bi_iter.bi_size, err);
8191
8192         if (dip->subio_endio)
8193                 err = dip->subio_endio(dip->inode, btrfs_io_bio(bio), err);
8194
8195         if (err) {
8196                 dip->errors = 1;
8197
8198                 /*
8199                  * before atomic variable goto zero, we must make sure
8200                  * dip->errors is perceived to be set.
8201                  */
8202                 smp_mb__before_atomic();
8203         }
8204
8205         /* if there are more bios still pending for this dio, just exit */
8206         if (!atomic_dec_and_test(&dip->pending_bios))
8207                 goto out;
8208
8209         if (dip->errors) {
8210                 bio_io_error(dip->orig_bio);
8211         } else {
8212                 dip->dio_bio->bi_error = 0;
8213                 bio_endio(dip->orig_bio);
8214         }
8215 out:
8216         bio_put(bio);
8217 }
8218
8219 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
8220                                        u64 first_sector, gfp_t gfp_flags)
8221 {
8222         struct bio *bio;
8223         bio = btrfs_bio_alloc(bdev, first_sector, BIO_MAX_PAGES, gfp_flags);
8224         if (bio)
8225                 bio_associate_current(bio);
8226         return bio;
8227 }
8228
8229 static inline int btrfs_lookup_and_bind_dio_csum(struct inode *inode,
8230                                                  struct btrfs_dio_private *dip,
8231                                                  struct bio *bio,
8232                                                  u64 file_offset)
8233 {
8234         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8235         struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
8236         int ret;
8237
8238         /*
8239          * We load all the csum data we need when we submit
8240          * the first bio to reduce the csum tree search and
8241          * contention.
8242          */
8243         if (dip->logical_offset == file_offset) {
8244                 ret = btrfs_lookup_bio_sums_dio(inode, dip->orig_bio,
8245                                                 file_offset);
8246                 if (ret)
8247                         return ret;
8248         }
8249
8250         if (bio == dip->orig_bio)
8251                 return 0;
8252
8253         file_offset -= dip->logical_offset;
8254         file_offset >>= inode->i_sb->s_blocksize_bits;
8255         io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
8256
8257         return 0;
8258 }
8259
8260 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
8261                                          u64 file_offset, int skip_sum,
8262                                          int async_submit)
8263 {
8264         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8265         struct btrfs_dio_private *dip = bio->bi_private;
8266         bool write = bio_op(bio) == REQ_OP_WRITE;
8267         int ret;
8268
8269         if (async_submit)
8270                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
8271
8272         bio_get(bio);
8273
8274         if (!write) {
8275                 ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA);
8276                 if (ret)
8277                         goto err;
8278         }
8279
8280         if (skip_sum)
8281                 goto map;
8282
8283         if (write && async_submit) {
8284                 ret = btrfs_wq_submit_bio(fs_info, inode, bio, 0, 0,
8285                                           file_offset,
8286                                           __btrfs_submit_bio_start_direct_io,
8287                                           __btrfs_submit_bio_done);
8288                 goto err;
8289         } else if (write) {
8290                 /*
8291                  * If we aren't doing async submit, calculate the csum of the
8292                  * bio now.
8293                  */
8294                 ret = btrfs_csum_one_bio(inode, bio, file_offset, 1);
8295                 if (ret)
8296                         goto err;
8297         } else {
8298                 ret = btrfs_lookup_and_bind_dio_csum(inode, dip, bio,
8299                                                      file_offset);
8300                 if (ret)
8301                         goto err;
8302         }
8303 map:
8304         ret = btrfs_map_bio(fs_info, bio, 0, async_submit);
8305 err:
8306         bio_put(bio);
8307         return ret;
8308 }
8309
8310 static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip,
8311                                     int skip_sum)
8312 {
8313         struct inode *inode = dip->inode;
8314         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8315         struct btrfs_root *root = BTRFS_I(inode)->root;
8316         struct bio *bio;
8317         struct bio *orig_bio = dip->orig_bio;
8318         struct bio_vec *bvec;
8319         u64 start_sector = orig_bio->bi_iter.bi_sector;
8320         u64 file_offset = dip->logical_offset;
8321         u64 submit_len = 0;
8322         u64 map_length;
8323         u32 blocksize = fs_info->sectorsize;
8324         int async_submit = 0;
8325         int nr_sectors;
8326         int ret;
8327         int i, j;
8328
8329         map_length = orig_bio->bi_iter.bi_size;
8330         ret = btrfs_map_block(fs_info, btrfs_op(orig_bio), start_sector << 9,
8331                               &map_length, NULL, 0);
8332         if (ret)
8333                 return -EIO;
8334
8335         if (map_length >= orig_bio->bi_iter.bi_size) {
8336                 bio = orig_bio;
8337                 dip->flags |= BTRFS_DIO_ORIG_BIO_SUBMITTED;
8338                 goto submit;
8339         }
8340
8341         /* async crcs make it difficult to collect full stripe writes. */
8342         if (btrfs_get_alloc_profile(root, 1) & BTRFS_BLOCK_GROUP_RAID56_MASK)
8343                 async_submit = 0;
8344         else
8345                 async_submit = 1;
8346
8347         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
8348         if (!bio)
8349                 return -ENOMEM;
8350
8351         bio->bi_opf = orig_bio->bi_opf;
8352         bio->bi_private = dip;
8353         bio->bi_end_io = btrfs_end_dio_bio;
8354         btrfs_io_bio(bio)->logical = file_offset;
8355         atomic_inc(&dip->pending_bios);
8356
8357         bio_for_each_segment_all(bvec, orig_bio, j) {
8358                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
8359                 i = 0;
8360 next_block:
8361                 if (unlikely(map_length < submit_len + blocksize ||
8362                     bio_add_page(bio, bvec->bv_page, blocksize,
8363                             bvec->bv_offset + (i * blocksize)) < blocksize)) {
8364                         /*
8365                          * inc the count before we submit the bio so
8366                          * we know the end IO handler won't happen before
8367                          * we inc the count. Otherwise, the dip might get freed
8368                          * before we're done setting it up
8369                          */
8370                         atomic_inc(&dip->pending_bios);
8371                         ret = __btrfs_submit_dio_bio(bio, inode,
8372                                                      file_offset, skip_sum,
8373                                                      async_submit);
8374                         if (ret) {
8375                                 bio_put(bio);
8376                                 atomic_dec(&dip->pending_bios);
8377                                 goto out_err;
8378                         }
8379
8380                         start_sector += submit_len >> 9;
8381                         file_offset += submit_len;
8382
8383                         submit_len = 0;
8384
8385                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
8386                                                   start_sector, GFP_NOFS);
8387                         if (!bio)
8388                                 goto out_err;
8389                         bio->bi_opf = orig_bio->bi_opf;
8390                         bio->bi_private = dip;
8391                         bio->bi_end_io = btrfs_end_dio_bio;
8392                         btrfs_io_bio(bio)->logical = file_offset;
8393
8394                         map_length = orig_bio->bi_iter.bi_size;
8395                         ret = btrfs_map_block(fs_info, btrfs_op(orig_bio),
8396                                               start_sector << 9,
8397                                               &map_length, NULL, 0);
8398                         if (ret) {
8399                                 bio_put(bio);
8400                                 goto out_err;
8401                         }
8402
8403                         goto next_block;
8404                 } else {
8405                         submit_len += blocksize;
8406                         if (--nr_sectors) {
8407                                 i++;
8408                                 goto next_block;
8409                         }
8410                 }
8411         }
8412
8413 submit:
8414         ret = __btrfs_submit_dio_bio(bio, inode, file_offset, skip_sum,
8415                                      async_submit);
8416         if (!ret)
8417                 return 0;
8418
8419         bio_put(bio);
8420 out_err:
8421         dip->errors = 1;
8422         /*
8423          * before atomic variable goto zero, we must
8424          * make sure dip->errors is perceived to be set.
8425          */
8426         smp_mb__before_atomic();
8427         if (atomic_dec_and_test(&dip->pending_bios))
8428                 bio_io_error(dip->orig_bio);
8429
8430         /* bio_end_io() will handle error, so we needn't return it */
8431         return 0;
8432 }
8433
8434 static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
8435                                 loff_t file_offset)
8436 {
8437         struct btrfs_dio_private *dip = NULL;
8438         struct bio *io_bio = NULL;
8439         struct btrfs_io_bio *btrfs_bio;
8440         int skip_sum;
8441         bool write = (bio_op(dio_bio) == REQ_OP_WRITE);
8442         int ret = 0;
8443
8444         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
8445
8446         io_bio = btrfs_bio_clone(dio_bio, GFP_NOFS);
8447         if (!io_bio) {
8448                 ret = -ENOMEM;
8449                 goto free_ordered;
8450         }
8451
8452         dip = kzalloc(sizeof(*dip), GFP_NOFS);
8453         if (!dip) {
8454                 ret = -ENOMEM;
8455                 goto free_ordered;
8456         }
8457
8458         dip->private = dio_bio->bi_private;
8459         dip->inode = inode;
8460         dip->logical_offset = file_offset;
8461         dip->bytes = dio_bio->bi_iter.bi_size;
8462         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
8463         io_bio->bi_private = dip;
8464         dip->orig_bio = io_bio;
8465         dip->dio_bio = dio_bio;
8466         atomic_set(&dip->pending_bios, 0);
8467         btrfs_bio = btrfs_io_bio(io_bio);
8468         btrfs_bio->logical = file_offset;
8469
8470         if (write) {
8471                 io_bio->bi_end_io = btrfs_endio_direct_write;
8472         } else {
8473                 io_bio->bi_end_io = btrfs_endio_direct_read;
8474                 dip->subio_endio = btrfs_subio_endio_read;
8475         }
8476
8477         /*
8478          * Reset the range for unsubmitted ordered extents (to a 0 length range)
8479          * even if we fail to submit a bio, because in such case we do the
8480          * corresponding error handling below and it must not be done a second
8481          * time by btrfs_direct_IO().
8482          */
8483         if (write) {
8484                 struct btrfs_dio_data *dio_data = current->journal_info;
8485
8486                 dio_data->unsubmitted_oe_range_end = dip->logical_offset +
8487                         dip->bytes;
8488                 dio_data->unsubmitted_oe_range_start =
8489                         dio_data->unsubmitted_oe_range_end;
8490         }
8491
8492         ret = btrfs_submit_direct_hook(dip, skip_sum);
8493         if (!ret)
8494                 return;
8495
8496         if (btrfs_bio->end_io)
8497                 btrfs_bio->end_io(btrfs_bio, ret);
8498
8499 free_ordered:
8500         /*
8501          * If we arrived here it means either we failed to submit the dip
8502          * or we either failed to clone the dio_bio or failed to allocate the
8503          * dip. If we cloned the dio_bio and allocated the dip, we can just
8504          * call bio_endio against our io_bio so that we get proper resource
8505          * cleanup if we fail to submit the dip, otherwise, we must do the
8506          * same as btrfs_endio_direct_[write|read] because we can't call these
8507          * callbacks - they require an allocated dip and a clone of dio_bio.
8508          */
8509         if (io_bio && dip) {
8510                 io_bio->bi_error = -EIO;
8511                 bio_endio(io_bio);
8512                 /*
8513                  * The end io callbacks free our dip, do the final put on io_bio
8514                  * and all the cleanup and final put for dio_bio (through
8515                  * dio_end_io()).
8516                  */
8517                 dip = NULL;
8518                 io_bio = NULL;
8519         } else {
8520                 if (write)
8521                         btrfs_endio_direct_write_update_ordered(inode,
8522                                                 file_offset,
8523                                                 dio_bio->bi_iter.bi_size,
8524                                                 0);
8525                 else
8526                         unlock_extent(&BTRFS_I(inode)->io_tree, file_offset,
8527                               file_offset + dio_bio->bi_iter.bi_size - 1);
8528
8529                 dio_bio->bi_error = -EIO;
8530                 /*
8531                  * Releases and cleans up our dio_bio, no need to bio_put()
8532                  * nor bio_endio()/bio_io_error() against dio_bio.
8533                  */
8534                 dio_end_io(dio_bio, ret);
8535         }
8536         if (io_bio)
8537                 bio_put(io_bio);
8538         kfree(dip);
8539 }
8540
8541 static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
8542                                struct kiocb *iocb,
8543                                const struct iov_iter *iter, loff_t offset)
8544 {
8545         int seg;
8546         int i;
8547         unsigned int blocksize_mask = fs_info->sectorsize - 1;
8548         ssize_t retval = -EINVAL;
8549
8550         if (offset & blocksize_mask)
8551                 goto out;
8552
8553         if (iov_iter_alignment(iter) & blocksize_mask)
8554                 goto out;
8555
8556         /* If this is a write we don't need to check anymore */
8557         if (iov_iter_rw(iter) != READ || !iter_is_iovec(iter))
8558                 return 0;
8559         /*
8560          * Check to make sure we don't have duplicate iov_base's in this
8561          * iovec, if so return EINVAL, otherwise we'll get csum errors
8562          * when reading back.
8563          */
8564         for (seg = 0; seg < iter->nr_segs; seg++) {
8565                 for (i = seg + 1; i < iter->nr_segs; i++) {
8566                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
8567                                 goto out;
8568                 }
8569         }
8570         retval = 0;
8571 out:
8572         return retval;
8573 }
8574
8575 static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
8576 {
8577         struct file *file = iocb->ki_filp;
8578         struct inode *inode = file->f_mapping->host;
8579         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8580         struct btrfs_dio_data dio_data = { 0 };
8581         loff_t offset = iocb->ki_pos;
8582         size_t count = 0;
8583         int flags = 0;
8584         bool wakeup = true;
8585         bool relock = false;
8586         ssize_t ret;
8587
8588         if (check_direct_IO(fs_info, iocb, iter, offset))
8589                 return 0;
8590
8591         inode_dio_begin(inode);
8592         smp_mb__after_atomic();
8593
8594         /*
8595          * The generic stuff only does filemap_write_and_wait_range, which
8596          * isn't enough if we've written compressed pages to this area, so
8597          * we need to flush the dirty pages again to make absolutely sure
8598          * that any outstanding dirty pages are on disk.
8599          */
8600         count = iov_iter_count(iter);
8601         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8602                      &BTRFS_I(inode)->runtime_flags))
8603                 filemap_fdatawrite_range(inode->i_mapping, offset,
8604                                          offset + count - 1);
8605
8606         if (iov_iter_rw(iter) == WRITE) {
8607                 /*
8608                  * If the write DIO is beyond the EOF, we need update
8609                  * the isize, but it is protected by i_mutex. So we can
8610                  * not unlock the i_mutex at this case.
8611                  */
8612                 if (offset + count <= inode->i_size) {
8613                         dio_data.overwrite = 1;
8614                         inode_unlock(inode);
8615                         relock = true;
8616                 }
8617                 ret = btrfs_delalloc_reserve_space(inode, offset, count);
8618                 if (ret)
8619                         goto out;
8620                 dio_data.outstanding_extents = count_max_extents(count);
8621
8622                 /*
8623                  * We need to know how many extents we reserved so that we can
8624                  * do the accounting properly if we go over the number we
8625                  * originally calculated.  Abuse current->journal_info for this.
8626                  */
8627                 dio_data.reserve = round_up(count,
8628                                             fs_info->sectorsize);
8629                 dio_data.unsubmitted_oe_range_start = (u64)offset;
8630                 dio_data.unsubmitted_oe_range_end = (u64)offset;
8631                 current->journal_info = &dio_data;
8632                 down_read(&BTRFS_I(inode)->dio_sem);
8633         } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
8634                                      &BTRFS_I(inode)->runtime_flags)) {
8635                 inode_dio_end(inode);
8636                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
8637                 wakeup = false;
8638         }
8639
8640         ret = __blockdev_direct_IO(iocb, inode,
8641                                    fs_info->fs_devices->latest_bdev,
8642                                    iter, btrfs_get_blocks_direct, NULL,
8643                                    btrfs_submit_direct, flags);
8644         if (iov_iter_rw(iter) == WRITE) {
8645                 up_read(&BTRFS_I(inode)->dio_sem);
8646                 current->journal_info = NULL;
8647                 if (ret < 0 && ret != -EIOCBQUEUED) {
8648                         if (dio_data.reserve)
8649                                 btrfs_delalloc_release_space(inode, offset,
8650                                                              dio_data.reserve);
8651                         /*
8652                          * On error we might have left some ordered extents
8653                          * without submitting corresponding bios for them, so
8654                          * cleanup them up to avoid other tasks getting them
8655                          * and waiting for them to complete forever.
8656                          */
8657                         if (dio_data.unsubmitted_oe_range_start <
8658                             dio_data.unsubmitted_oe_range_end)
8659                                 btrfs_endio_direct_write_update_ordered(inode,
8660                                         dio_data.unsubmitted_oe_range_start,
8661                                         dio_data.unsubmitted_oe_range_end -
8662                                         dio_data.unsubmitted_oe_range_start,
8663                                         0);
8664                 } else if (ret >= 0 && (size_t)ret < count)
8665                         btrfs_delalloc_release_space(inode, offset,
8666                                                      count - (size_t)ret);
8667         }
8668 out:
8669         if (wakeup)
8670                 inode_dio_end(inode);
8671         if (relock)
8672                 inode_lock(inode);
8673
8674         return ret;
8675 }
8676
8677 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
8678
8679 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
8680                 __u64 start, __u64 len)
8681 {
8682         int     ret;
8683
8684         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
8685         if (ret)
8686                 return ret;
8687
8688         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
8689 }
8690
8691 int btrfs_readpage(struct file *file, struct page *page)
8692 {
8693         struct extent_io_tree *tree;
8694         tree = &BTRFS_I(page->mapping->host)->io_tree;
8695         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
8696 }
8697
8698 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
8699 {
8700         struct extent_io_tree *tree;
8701         struct inode *inode = page->mapping->host;
8702         int ret;
8703
8704         if (current->flags & PF_MEMALLOC) {
8705                 redirty_page_for_writepage(wbc, page);
8706                 unlock_page(page);
8707                 return 0;
8708         }
8709
8710         /*
8711          * If we are under memory pressure we will call this directly from the
8712          * VM, we need to make sure we have the inode referenced for the ordered
8713          * extent.  If not just return like we didn't do anything.
8714          */
8715         if (!igrab(inode)) {
8716                 redirty_page_for_writepage(wbc, page);
8717                 return AOP_WRITEPAGE_ACTIVATE;
8718         }
8719         tree = &BTRFS_I(page->mapping->host)->io_tree;
8720         ret = extent_write_full_page(tree, page, btrfs_get_extent, wbc);
8721         btrfs_add_delayed_iput(inode);
8722         return ret;
8723 }
8724
8725 static int btrfs_writepages(struct address_space *mapping,
8726                             struct writeback_control *wbc)
8727 {
8728         struct extent_io_tree *tree;
8729
8730         tree = &BTRFS_I(mapping->host)->io_tree;
8731         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
8732 }
8733
8734 static int
8735 btrfs_readpages(struct file *file, struct address_space *mapping,
8736                 struct list_head *pages, unsigned nr_pages)
8737 {
8738         struct extent_io_tree *tree;
8739         tree = &BTRFS_I(mapping->host)->io_tree;
8740         return extent_readpages(tree, mapping, pages, nr_pages,
8741                                 btrfs_get_extent);
8742 }
8743 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8744 {
8745         struct extent_io_tree *tree;
8746         struct extent_map_tree *map;
8747         int ret;
8748
8749         tree = &BTRFS_I(page->mapping->host)->io_tree;
8750         map = &BTRFS_I(page->mapping->host)->extent_tree;
8751         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
8752         if (ret == 1) {
8753                 ClearPagePrivate(page);
8754                 set_page_private(page, 0);
8755                 put_page(page);
8756         }
8757         return ret;
8758 }
8759
8760 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8761 {
8762         if (PageWriteback(page) || PageDirty(page))
8763                 return 0;
8764         return __btrfs_releasepage(page, gfp_flags);
8765 }
8766
8767 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
8768                                  unsigned int length)
8769 {
8770         struct inode *inode = page->mapping->host;
8771         struct extent_io_tree *tree;
8772         struct btrfs_ordered_extent *ordered;
8773         struct extent_state *cached_state = NULL;
8774         u64 page_start = page_offset(page);
8775         u64 page_end = page_start + PAGE_SIZE - 1;
8776         u64 start;
8777         u64 end;
8778         int inode_evicting = inode->i_state & I_FREEING;
8779
8780         /*
8781          * we have the page locked, so new writeback can't start,
8782          * and the dirty bit won't be cleared while we are here.
8783          *
8784          * Wait for IO on this page so that we can safely clear
8785          * the PagePrivate2 bit and do ordered accounting
8786          */
8787         wait_on_page_writeback(page);
8788
8789         tree = &BTRFS_I(inode)->io_tree;
8790         if (offset) {
8791                 btrfs_releasepage(page, GFP_NOFS);
8792                 return;
8793         }
8794
8795         if (!inode_evicting)
8796                 lock_extent_bits(tree, page_start, page_end, &cached_state);
8797 again:
8798         start = page_start;
8799         ordered = btrfs_lookup_ordered_range(inode, start,
8800                                         page_end - start + 1);
8801         if (ordered) {
8802                 end = min(page_end, ordered->file_offset + ordered->len - 1);
8803                 /*
8804                  * IO on this page will never be started, so we need
8805                  * to account for any ordered extents now
8806                  */
8807                 if (!inode_evicting)
8808                         clear_extent_bit(tree, start, end,
8809                                          EXTENT_DIRTY | EXTENT_DELALLOC |
8810                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
8811                                          EXTENT_DEFRAG, 1, 0, &cached_state,
8812                                          GFP_NOFS);
8813                 /*
8814                  * whoever cleared the private bit is responsible
8815                  * for the finish_ordered_io
8816                  */
8817                 if (TestClearPagePrivate2(page)) {
8818                         struct btrfs_ordered_inode_tree *tree;
8819                         u64 new_len;
8820
8821                         tree = &BTRFS_I(inode)->ordered_tree;
8822
8823                         spin_lock_irq(&tree->lock);
8824                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
8825                         new_len = start - ordered->file_offset;
8826                         if (new_len < ordered->truncated_len)
8827                                 ordered->truncated_len = new_len;
8828                         spin_unlock_irq(&tree->lock);
8829
8830                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
8831                                                            start,
8832                                                            end - start + 1, 1))
8833                                 btrfs_finish_ordered_io(ordered);
8834                 }
8835                 btrfs_put_ordered_extent(ordered);
8836                 if (!inode_evicting) {
8837                         cached_state = NULL;
8838                         lock_extent_bits(tree, start, end,
8839                                          &cached_state);
8840                 }
8841
8842                 start = end + 1;
8843                 if (start < page_end)
8844                         goto again;
8845         }
8846
8847         /*
8848          * Qgroup reserved space handler
8849          * Page here will be either
8850          * 1) Already written to disk
8851          *    In this case, its reserved space is released from data rsv map
8852          *    and will be freed by delayed_ref handler finally.
8853          *    So even we call qgroup_free_data(), it won't decrease reserved
8854          *    space.
8855          * 2) Not written to disk
8856          *    This means the reserved space should be freed here. However,
8857          *    if a truncate invalidates the page (by clearing PageDirty)
8858          *    and the page is accounted for while allocating extent
8859          *    in btrfs_check_data_free_space() we let delayed_ref to
8860          *    free the entire extent.
8861          */
8862         if (PageDirty(page))
8863                 btrfs_qgroup_free_data(inode, page_start, PAGE_SIZE);
8864         if (!inode_evicting) {
8865                 clear_extent_bit(tree, page_start, page_end,
8866                                  EXTENT_LOCKED | EXTENT_DIRTY |
8867                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
8868                                  EXTENT_DEFRAG, 1, 1,
8869                                  &cached_state, GFP_NOFS);
8870
8871                 __btrfs_releasepage(page, GFP_NOFS);
8872         }
8873
8874         ClearPageChecked(page);
8875         if (PagePrivate(page)) {
8876                 ClearPagePrivate(page);
8877                 set_page_private(page, 0);
8878                 put_page(page);
8879         }
8880 }
8881
8882 /*
8883  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
8884  * called from a page fault handler when a page is first dirtied. Hence we must
8885  * be careful to check for EOF conditions here. We set the page up correctly
8886  * for a written page which means we get ENOSPC checking when writing into
8887  * holes and correct delalloc and unwritten extent mapping on filesystems that
8888  * support these features.
8889  *
8890  * We are not allowed to take the i_mutex here so we have to play games to
8891  * protect against truncate races as the page could now be beyond EOF.  Because
8892  * vmtruncate() writes the inode size before removing pages, once we have the
8893  * page lock we can determine safely if the page is beyond EOF. If it is not
8894  * beyond EOF, then the page is guaranteed safe against truncation until we
8895  * unlock the page.
8896  */
8897 int btrfs_page_mkwrite(struct vm_fault *vmf)
8898 {
8899         struct page *page = vmf->page;
8900         struct inode *inode = file_inode(vmf->vma->vm_file);
8901         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8902         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
8903         struct btrfs_ordered_extent *ordered;
8904         struct extent_state *cached_state = NULL;
8905         char *kaddr;
8906         unsigned long zero_start;
8907         loff_t size;
8908         int ret;
8909         int reserved = 0;
8910         u64 reserved_space;
8911         u64 page_start;
8912         u64 page_end;
8913         u64 end;
8914
8915         reserved_space = PAGE_SIZE;
8916
8917         sb_start_pagefault(inode->i_sb);
8918         page_start = page_offset(page);
8919         page_end = page_start + PAGE_SIZE - 1;
8920         end = page_end;
8921
8922         /*
8923          * Reserving delalloc space after obtaining the page lock can lead to
8924          * deadlock. For example, if a dirty page is locked by this function
8925          * and the call to btrfs_delalloc_reserve_space() ends up triggering
8926          * dirty page write out, then the btrfs_writepage() function could
8927          * end up waiting indefinitely to get a lock on the page currently
8928          * being processed by btrfs_page_mkwrite() function.
8929          */
8930         ret = btrfs_delalloc_reserve_space(inode, page_start,
8931                                            reserved_space);
8932         if (!ret) {
8933                 ret = file_update_time(vmf->vma->vm_file);
8934                 reserved = 1;
8935         }
8936         if (ret) {
8937                 if (ret == -ENOMEM)
8938                         ret = VM_FAULT_OOM;
8939                 else /* -ENOSPC, -EIO, etc */
8940                         ret = VM_FAULT_SIGBUS;
8941                 if (reserved)
8942                         goto out;
8943                 goto out_noreserve;
8944         }
8945
8946         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
8947 again:
8948         lock_page(page);
8949         size = i_size_read(inode);
8950
8951         if ((page->mapping != inode->i_mapping) ||
8952             (page_start >= size)) {
8953                 /* page got truncated out from underneath us */
8954                 goto out_unlock;
8955         }
8956         wait_on_page_writeback(page);
8957
8958         lock_extent_bits(io_tree, page_start, page_end, &cached_state);
8959         set_page_extent_mapped(page);
8960
8961         /*
8962          * we can't set the delalloc bits if there are pending ordered
8963          * extents.  Drop our locks and wait for them to finish
8964          */
8965         ordered = btrfs_lookup_ordered_range(inode, page_start, PAGE_SIZE);
8966         if (ordered) {
8967                 unlock_extent_cached(io_tree, page_start, page_end,
8968                                      &cached_state, GFP_NOFS);
8969                 unlock_page(page);
8970                 btrfs_start_ordered_extent(inode, ordered, 1);
8971                 btrfs_put_ordered_extent(ordered);
8972                 goto again;
8973         }
8974
8975         if (page->index == ((size - 1) >> PAGE_SHIFT)) {
8976                 reserved_space = round_up(size - page_start,
8977                                           fs_info->sectorsize);
8978                 if (reserved_space < PAGE_SIZE) {
8979                         end = page_start + reserved_space - 1;
8980                         spin_lock(&BTRFS_I(inode)->lock);
8981                         BTRFS_I(inode)->outstanding_extents++;
8982                         spin_unlock(&BTRFS_I(inode)->lock);
8983                         btrfs_delalloc_release_space(inode, page_start,
8984                                                 PAGE_SIZE - reserved_space);
8985                 }
8986         }
8987
8988         /*
8989          * page_mkwrite gets called when the page is firstly dirtied after it's
8990          * faulted in, but write(2) could also dirty a page and set delalloc
8991          * bits, thus in this case for space account reason, we still need to
8992          * clear any delalloc bits within this page range since we have to
8993          * reserve data&meta space before lock_page() (see above comments).
8994          */
8995         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, end,
8996                           EXTENT_DIRTY | EXTENT_DELALLOC |
8997                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
8998                           0, 0, &cached_state, GFP_NOFS);
8999
9000         ret = btrfs_set_extent_delalloc(inode, page_start, end,
9001                                         &cached_state, 0);
9002         if (ret) {
9003                 unlock_extent_cached(io_tree, page_start, page_end,
9004                                      &cached_state, GFP_NOFS);
9005                 ret = VM_FAULT_SIGBUS;
9006                 goto out_unlock;
9007         }
9008         ret = 0;
9009
9010         /* page is wholly or partially inside EOF */
9011         if (page_start + PAGE_SIZE > size)
9012                 zero_start = size & ~PAGE_MASK;
9013         else
9014                 zero_start = PAGE_SIZE;
9015
9016         if (zero_start != PAGE_SIZE) {
9017                 kaddr = kmap(page);
9018                 memset(kaddr + zero_start, 0, PAGE_SIZE - zero_start);
9019                 flush_dcache_page(page);
9020                 kunmap(page);
9021         }
9022         ClearPageChecked(page);
9023         set_page_dirty(page);
9024         SetPageUptodate(page);
9025
9026         BTRFS_I(inode)->last_trans = fs_info->generation;
9027         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
9028         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
9029
9030         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
9031
9032 out_unlock:
9033         if (!ret) {
9034                 sb_end_pagefault(inode->i_sb);
9035                 return VM_FAULT_LOCKED;
9036         }
9037         unlock_page(page);
9038 out:
9039         btrfs_delalloc_release_space(inode, page_start, reserved_space);
9040 out_noreserve:
9041         sb_end_pagefault(inode->i_sb);
9042         return ret;
9043 }
9044
9045 static int btrfs_truncate(struct inode *inode)
9046 {
9047         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
9048         struct btrfs_root *root = BTRFS_I(inode)->root;
9049         struct btrfs_block_rsv *rsv;
9050         int ret = 0;
9051         int err = 0;
9052         struct btrfs_trans_handle *trans;
9053         u64 mask = fs_info->sectorsize - 1;
9054         u64 min_size = btrfs_calc_trunc_metadata_size(fs_info, 1);
9055
9056         ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
9057                                        (u64)-1);
9058         if (ret)
9059                 return ret;
9060
9061         /*
9062          * Yes ladies and gentlemen, this is indeed ugly.  The fact is we have
9063          * 3 things going on here
9064          *
9065          * 1) We need to reserve space for our orphan item and the space to
9066          * delete our orphan item.  Lord knows we don't want to have a dangling
9067          * orphan item because we didn't reserve space to remove it.
9068          *
9069          * 2) We need to reserve space to update our inode.
9070          *
9071          * 3) We need to have something to cache all the space that is going to
9072          * be free'd up by the truncate operation, but also have some slack
9073          * space reserved in case it uses space during the truncate (thank you
9074          * very much snapshotting).
9075          *
9076          * And we need these to all be separate.  The fact is we can use a lot of
9077          * space doing the truncate, and we have no earthly idea how much space
9078          * we will use, so we need the truncate reservation to be separate so it
9079          * doesn't end up using space reserved for updating the inode or
9080          * removing the orphan item.  We also need to be able to stop the
9081          * transaction and start a new one, which means we need to be able to
9082          * update the inode several times, and we have no idea of knowing how
9083          * many times that will be, so we can't just reserve 1 item for the
9084          * entirety of the operation, so that has to be done separately as well.
9085          * Then there is the orphan item, which does indeed need to be held on
9086          * to for the whole operation, and we need nobody to touch this reserved
9087          * space except the orphan code.
9088          *
9089          * So that leaves us with
9090          *
9091          * 1) root->orphan_block_rsv - for the orphan deletion.
9092          * 2) rsv - for the truncate reservation, which we will steal from the
9093          * transaction reservation.
9094          * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
9095          * updating the inode.
9096          */
9097         rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
9098         if (!rsv)
9099                 return -ENOMEM;
9100         rsv->size = min_size;
9101         rsv->failfast = 1;
9102
9103         /*
9104          * 1 for the truncate slack space
9105          * 1 for updating the inode.
9106          */
9107         trans = btrfs_start_transaction(root, 2);
9108         if (IS_ERR(trans)) {
9109                 err = PTR_ERR(trans);
9110                 goto out;
9111         }
9112
9113         /* Migrate the slack space for the truncate to our reserve */
9114         ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
9115                                       min_size, 0);
9116         BUG_ON(ret);
9117
9118         /*
9119          * So if we truncate and then write and fsync we normally would just
9120          * write the extents that changed, which is a problem if we need to
9121          * first truncate that entire inode.  So set this flag so we write out
9122          * all of the extents in the inode to the sync log so we're completely
9123          * safe.
9124          */
9125         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
9126         trans->block_rsv = rsv;
9127
9128         while (1) {
9129                 ret = btrfs_truncate_inode_items(trans, root, inode,
9130                                                  inode->i_size,
9131                                                  BTRFS_EXTENT_DATA_KEY);
9132                 if (ret != -ENOSPC && ret != -EAGAIN) {
9133                         err = ret;
9134                         break;
9135                 }
9136
9137                 trans->block_rsv = &fs_info->trans_block_rsv;
9138                 ret = btrfs_update_inode(trans, root, inode);
9139                 if (ret) {
9140                         err = ret;
9141                         break;
9142                 }
9143
9144                 btrfs_end_transaction(trans);
9145                 btrfs_btree_balance_dirty(fs_info);
9146
9147                 trans = btrfs_start_transaction(root, 2);
9148                 if (IS_ERR(trans)) {
9149                         ret = err = PTR_ERR(trans);
9150                         trans = NULL;
9151                         break;
9152                 }
9153
9154                 btrfs_block_rsv_release(fs_info, rsv, -1);
9155                 ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
9156                                               rsv, min_size, 0);
9157                 BUG_ON(ret);    /* shouldn't happen */
9158                 trans->block_rsv = rsv;
9159         }
9160
9161         if (ret == 0 && inode->i_nlink > 0) {
9162                 trans->block_rsv = root->orphan_block_rsv;
9163                 ret = btrfs_orphan_del(trans, inode);
9164                 if (ret)
9165                         err = ret;
9166         }
9167
9168         if (trans) {
9169                 trans->block_rsv = &fs_info->trans_block_rsv;
9170                 ret = btrfs_update_inode(trans, root, inode);
9171                 if (ret && !err)
9172                         err = ret;
9173
9174                 ret = btrfs_end_transaction(trans);
9175                 btrfs_btree_balance_dirty(fs_info);
9176         }
9177 out:
9178         btrfs_free_block_rsv(fs_info, rsv);
9179
9180         if (ret && !err)
9181                 err = ret;
9182
9183         return err;
9184 }
9185
9186 /*
9187  * create a new subvolume directory/inode (helper for the ioctl).
9188  */
9189 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
9190                              struct btrfs_root *new_root,
9191                              struct btrfs_root *parent_root,
9192                              u64 new_dirid)
9193 {
9194         struct inode *inode;
9195         int err;
9196         u64 index = 0;
9197
9198         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
9199                                 new_dirid, new_dirid,
9200                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
9201                                 &index);
9202         if (IS_ERR(inode))
9203                 return PTR_ERR(inode);
9204         inode->i_op = &btrfs_dir_inode_operations;
9205         inode->i_fop = &btrfs_dir_file_operations;
9206
9207         set_nlink(inode, 1);
9208         btrfs_i_size_write(inode, 0);
9209         unlock_new_inode(inode);
9210
9211         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
9212         if (err)
9213                 btrfs_err(new_root->fs_info,
9214                           "error inheriting subvolume %llu properties: %d",
9215                           new_root->root_key.objectid, err);
9216
9217         err = btrfs_update_inode(trans, new_root, inode);
9218
9219         iput(inode);
9220         return err;
9221 }
9222
9223 struct inode *btrfs_alloc_inode(struct super_block *sb)
9224 {
9225         struct btrfs_inode *ei;
9226         struct inode *inode;
9227
9228         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
9229         if (!ei)
9230                 return NULL;
9231
9232         ei->root = NULL;
9233         ei->generation = 0;
9234         ei->last_trans = 0;
9235         ei->last_sub_trans = 0;
9236         ei->logged_trans = 0;
9237         ei->delalloc_bytes = 0;
9238         ei->defrag_bytes = 0;
9239         ei->disk_i_size = 0;
9240         ei->flags = 0;
9241         ei->csum_bytes = 0;
9242         ei->index_cnt = (u64)-1;
9243         ei->dir_index = 0;
9244         ei->last_unlink_trans = 0;
9245         ei->last_log_commit = 0;
9246         ei->delayed_iput_count = 0;
9247
9248         spin_lock_init(&ei->lock);
9249         ei->outstanding_extents = 0;
9250         ei->reserved_extents = 0;
9251
9252         ei->runtime_flags = 0;
9253         ei->force_compress = BTRFS_COMPRESS_NONE;
9254
9255         ei->delayed_node = NULL;
9256
9257         ei->i_otime.tv_sec = 0;
9258         ei->i_otime.tv_nsec = 0;
9259
9260         inode = &ei->vfs_inode;
9261         extent_map_tree_init(&ei->extent_tree);
9262         extent_io_tree_init(&ei->io_tree, &inode->i_data);
9263         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
9264         ei->io_tree.track_uptodate = 1;
9265         ei->io_failure_tree.track_uptodate = 1;
9266         atomic_set(&ei->sync_writers, 0);
9267         mutex_init(&ei->log_mutex);
9268         mutex_init(&ei->delalloc_mutex);
9269         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
9270         INIT_LIST_HEAD(&ei->delalloc_inodes);
9271         INIT_LIST_HEAD(&ei->delayed_iput);
9272         RB_CLEAR_NODE(&ei->rb_node);
9273         init_rwsem(&ei->dio_sem);
9274
9275         return inode;
9276 }
9277
9278 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
9279 void btrfs_test_destroy_inode(struct inode *inode)
9280 {
9281         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
9282         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9283 }
9284 #endif
9285
9286 static void btrfs_i_callback(struct rcu_head *head)
9287 {
9288         struct inode *inode = container_of(head, struct inode, i_rcu);
9289         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9290 }
9291
9292 void btrfs_destroy_inode(struct inode *inode)
9293 {
9294         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
9295         struct btrfs_ordered_extent *ordered;
9296         struct btrfs_root *root = BTRFS_I(inode)->root;
9297
9298         WARN_ON(!hlist_empty(&inode->i_dentry));
9299         WARN_ON(inode->i_data.nrpages);
9300         WARN_ON(BTRFS_I(inode)->outstanding_extents);
9301         WARN_ON(BTRFS_I(inode)->reserved_extents);
9302         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
9303         WARN_ON(BTRFS_I(inode)->csum_bytes);
9304         WARN_ON(BTRFS_I(inode)->defrag_bytes);
9305
9306         /*
9307          * This can happen where we create an inode, but somebody else also
9308          * created the same inode and we need to destroy the one we already
9309          * created.
9310          */
9311         if (!root)
9312                 goto free;
9313
9314         if (test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
9315                      &BTRFS_I(inode)->runtime_flags)) {
9316                 btrfs_info(fs_info, "inode %llu still on the orphan list",
9317                            btrfs_ino(BTRFS_I(inode)));
9318                 atomic_dec(&root->orphan_inodes);
9319         }
9320
9321         while (1) {
9322                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
9323                 if (!ordered)
9324                         break;
9325                 else {
9326                         btrfs_err(fs_info,
9327                                   "found ordered extent %llu %llu on inode cleanup",
9328                                   ordered->file_offset, ordered->len);
9329                         btrfs_remove_ordered_extent(inode, ordered);
9330                         btrfs_put_ordered_extent(ordered);
9331                         btrfs_put_ordered_extent(ordered);
9332                 }
9333         }
9334         btrfs_qgroup_check_reserved_leak(inode);
9335         inode_tree_del(inode);
9336         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
9337 free:
9338         call_rcu(&inode->i_rcu, btrfs_i_callback);
9339 }
9340
9341 int btrfs_drop_inode(struct inode *inode)
9342 {
9343         struct btrfs_root *root = BTRFS_I(inode)->root;
9344
9345         if (root == NULL)
9346                 return 1;
9347
9348         /* the snap/subvol tree is on deleting */
9349         if (btrfs_root_refs(&root->root_item) == 0)
9350                 return 1;
9351         else
9352                 return generic_drop_inode(inode);
9353 }
9354
9355 static void init_once(void *foo)
9356 {
9357         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
9358
9359         inode_init_once(&ei->vfs_inode);
9360 }
9361
9362 void btrfs_destroy_cachep(void)
9363 {
9364         /*
9365          * Make sure all delayed rcu free inodes are flushed before we
9366          * destroy cache.
9367          */
9368         rcu_barrier();
9369         kmem_cache_destroy(btrfs_inode_cachep);
9370         kmem_cache_destroy(btrfs_trans_handle_cachep);
9371         kmem_cache_destroy(btrfs_transaction_cachep);
9372         kmem_cache_destroy(btrfs_path_cachep);
9373         kmem_cache_destroy(btrfs_free_space_cachep);
9374 }
9375
9376 int btrfs_init_cachep(void)
9377 {
9378         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
9379                         sizeof(struct btrfs_inode), 0,
9380                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT,
9381                         init_once);
9382         if (!btrfs_inode_cachep)
9383                 goto fail;
9384
9385         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
9386                         sizeof(struct btrfs_trans_handle), 0,
9387                         SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
9388         if (!btrfs_trans_handle_cachep)
9389                 goto fail;
9390
9391         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
9392                         sizeof(struct btrfs_transaction), 0,
9393                         SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
9394         if (!btrfs_transaction_cachep)
9395                 goto fail;
9396
9397         btrfs_path_cachep = kmem_cache_create("btrfs_path",
9398                         sizeof(struct btrfs_path), 0,
9399                         SLAB_MEM_SPREAD, NULL);
9400         if (!btrfs_path_cachep)
9401                 goto fail;
9402
9403         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
9404                         sizeof(struct btrfs_free_space), 0,
9405                         SLAB_MEM_SPREAD, NULL);
9406         if (!btrfs_free_space_cachep)
9407                 goto fail;
9408
9409         return 0;
9410 fail:
9411         btrfs_destroy_cachep();
9412         return -ENOMEM;
9413 }
9414
9415 static int btrfs_getattr(struct vfsmount *mnt,
9416                          struct dentry *dentry, struct kstat *stat)
9417 {
9418         u64 delalloc_bytes;
9419         struct inode *inode = d_inode(dentry);
9420         u32 blocksize = inode->i_sb->s_blocksize;
9421
9422         generic_fillattr(inode, stat);
9423         stat->dev = BTRFS_I(inode)->root->anon_dev;
9424
9425         spin_lock(&BTRFS_I(inode)->lock);
9426         delalloc_bytes = BTRFS_I(inode)->delalloc_bytes;
9427         spin_unlock(&BTRFS_I(inode)->lock);
9428         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
9429                         ALIGN(delalloc_bytes, blocksize)) >> 9;
9430         return 0;
9431 }
9432
9433 static int btrfs_rename_exchange(struct inode *old_dir,
9434                               struct dentry *old_dentry,
9435                               struct inode *new_dir,
9436                               struct dentry *new_dentry)
9437 {
9438         struct btrfs_fs_info *fs_info = btrfs_sb(old_dir->i_sb);
9439         struct btrfs_trans_handle *trans;
9440         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9441         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9442         struct inode *new_inode = new_dentry->d_inode;
9443         struct inode *old_inode = old_dentry->d_inode;
9444         struct timespec ctime = current_time(old_inode);
9445         struct dentry *parent;
9446         u64 old_ino = btrfs_ino(BTRFS_I(old_inode));
9447         u64 new_ino = btrfs_ino(BTRFS_I(new_inode));
9448         u64 old_idx = 0;
9449         u64 new_idx = 0;
9450         u64 root_objectid;
9451         int ret;
9452         bool root_log_pinned = false;
9453         bool dest_log_pinned = false;
9454
9455         /* we only allow rename subvolume link between subvolumes */
9456         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9457                 return -EXDEV;
9458
9459         /* close the race window with snapshot create/destroy ioctl */
9460         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9461                 down_read(&fs_info->subvol_sem);
9462         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9463                 down_read(&fs_info->subvol_sem);
9464
9465         /*
9466          * We want to reserve the absolute worst case amount of items.  So if
9467          * both inodes are subvols and we need to unlink them then that would
9468          * require 4 item modifications, but if they are both normal inodes it
9469          * would require 5 item modifications, so we'll assume their normal
9470          * inodes.  So 5 * 2 is 10, plus 2 for the new links, so 12 total items
9471          * should cover the worst case number of items we'll modify.
9472          */
9473         trans = btrfs_start_transaction(root, 12);
9474         if (IS_ERR(trans)) {
9475                 ret = PTR_ERR(trans);
9476                 goto out_notrans;
9477         }
9478
9479         /*
9480          * We need to find a free sequence number both in the source and
9481          * in the destination directory for the exchange.
9482          */
9483         ret = btrfs_set_inode_index(new_dir, &old_idx);
9484         if (ret)
9485                 goto out_fail;
9486         ret = btrfs_set_inode_index(old_dir, &new_idx);
9487         if (ret)
9488                 goto out_fail;
9489
9490         BTRFS_I(old_inode)->dir_index = 0ULL;
9491         BTRFS_I(new_inode)->dir_index = 0ULL;
9492
9493         /* Reference for the source. */
9494         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9495                 /* force full log commit if subvolume involved. */
9496                 btrfs_set_log_full_commit(fs_info, trans);
9497         } else {
9498                 btrfs_pin_log_trans(root);
9499                 root_log_pinned = true;
9500                 ret = btrfs_insert_inode_ref(trans, dest,
9501                                              new_dentry->d_name.name,
9502                                              new_dentry->d_name.len,
9503                                              old_ino,
9504                                              btrfs_ino(BTRFS_I(new_dir)),
9505                                              old_idx);
9506                 if (ret)
9507                         goto out_fail;
9508         }
9509
9510         /* And now for the dest. */
9511         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9512                 /* force full log commit if subvolume involved. */
9513                 btrfs_set_log_full_commit(fs_info, trans);
9514         } else {
9515                 btrfs_pin_log_trans(dest);
9516                 dest_log_pinned = true;
9517                 ret = btrfs_insert_inode_ref(trans, root,
9518                                              old_dentry->d_name.name,
9519                                              old_dentry->d_name.len,
9520                                              new_ino,
9521                                              btrfs_ino(BTRFS_I(old_dir)),
9522                                              new_idx);
9523                 if (ret)
9524                         goto out_fail;
9525         }
9526
9527         /* Update inode version and ctime/mtime. */
9528         inode_inc_iversion(old_dir);
9529         inode_inc_iversion(new_dir);
9530         inode_inc_iversion(old_inode);
9531         inode_inc_iversion(new_inode);
9532         old_dir->i_ctime = old_dir->i_mtime = ctime;
9533         new_dir->i_ctime = new_dir->i_mtime = ctime;
9534         old_inode->i_ctime = ctime;
9535         new_inode->i_ctime = ctime;
9536
9537         if (old_dentry->d_parent != new_dentry->d_parent) {
9538                 btrfs_record_unlink_dir(trans, BTRFS_I(old_dir),
9539                                 BTRFS_I(old_inode), 1);
9540                 btrfs_record_unlink_dir(trans, BTRFS_I(new_dir),
9541                                 BTRFS_I(new_inode), 1);
9542         }
9543
9544         /* src is a subvolume */
9545         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9546                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9547                 ret = btrfs_unlink_subvol(trans, root, old_dir,
9548                                           root_objectid,
9549                                           old_dentry->d_name.name,
9550                                           old_dentry->d_name.len);
9551         } else { /* src is an inode */
9552                 ret = __btrfs_unlink_inode(trans, root, BTRFS_I(old_dir),
9553                                            BTRFS_I(old_dentry->d_inode),
9554                                            old_dentry->d_name.name,
9555                                            old_dentry->d_name.len);
9556                 if (!ret)
9557                         ret = btrfs_update_inode(trans, root, old_inode);
9558         }
9559         if (ret) {
9560                 btrfs_abort_transaction(trans, ret);
9561                 goto out_fail;
9562         }
9563
9564         /* dest is a subvolume */
9565         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9566                 root_objectid = BTRFS_I(new_inode)->root->root_key.objectid;
9567                 ret = btrfs_unlink_subvol(trans, dest, new_dir,
9568                                           root_objectid,
9569                                           new_dentry->d_name.name,
9570                                           new_dentry->d_name.len);
9571         } else { /* dest is an inode */
9572                 ret = __btrfs_unlink_inode(trans, dest, BTRFS_I(new_dir),
9573                                            BTRFS_I(new_dentry->d_inode),
9574                                            new_dentry->d_name.name,
9575                                            new_dentry->d_name.len);
9576                 if (!ret)
9577                         ret = btrfs_update_inode(trans, dest, new_inode);
9578         }
9579         if (ret) {
9580                 btrfs_abort_transaction(trans, ret);
9581                 goto out_fail;
9582         }
9583
9584         ret = btrfs_add_link(trans, new_dir, old_inode,
9585                              new_dentry->d_name.name,
9586                              new_dentry->d_name.len, 0, old_idx);
9587         if (ret) {
9588                 btrfs_abort_transaction(trans, ret);
9589                 goto out_fail;
9590         }
9591
9592         ret = btrfs_add_link(trans, old_dir, new_inode,
9593                              old_dentry->d_name.name,
9594                              old_dentry->d_name.len, 0, new_idx);
9595         if (ret) {
9596                 btrfs_abort_transaction(trans, ret);
9597                 goto out_fail;
9598         }
9599
9600         if (old_inode->i_nlink == 1)
9601                 BTRFS_I(old_inode)->dir_index = old_idx;
9602         if (new_inode->i_nlink == 1)
9603                 BTRFS_I(new_inode)->dir_index = new_idx;
9604
9605         if (root_log_pinned) {
9606                 parent = new_dentry->d_parent;
9607                 btrfs_log_new_name(trans, BTRFS_I(old_inode), BTRFS_I(old_dir),
9608                                 parent);
9609                 btrfs_end_log_trans(root);
9610                 root_log_pinned = false;
9611         }
9612         if (dest_log_pinned) {
9613                 parent = old_dentry->d_parent;
9614                 btrfs_log_new_name(trans, BTRFS_I(new_inode), BTRFS_I(new_dir),
9615                                 parent);
9616                 btrfs_end_log_trans(dest);
9617                 dest_log_pinned = false;
9618         }
9619 out_fail:
9620         /*
9621          * If we have pinned a log and an error happened, we unpin tasks
9622          * trying to sync the log and force them to fallback to a transaction
9623          * commit if the log currently contains any of the inodes involved in
9624          * this rename operation (to ensure we do not persist a log with an
9625          * inconsistent state for any of these inodes or leading to any
9626          * inconsistencies when replayed). If the transaction was aborted, the
9627          * abortion reason is propagated to userspace when attempting to commit
9628          * the transaction. If the log does not contain any of these inodes, we
9629          * allow the tasks to sync it.
9630          */
9631         if (ret && (root_log_pinned || dest_log_pinned)) {
9632                 if (btrfs_inode_in_log(BTRFS_I(old_dir), fs_info->generation) ||
9633                     btrfs_inode_in_log(BTRFS_I(new_dir), fs_info->generation) ||
9634                     btrfs_inode_in_log(BTRFS_I(old_inode), fs_info->generation) ||
9635                     (new_inode &&
9636                      btrfs_inode_in_log(BTRFS_I(new_inode), fs_info->generation)))
9637                         btrfs_set_log_full_commit(fs_info, trans);
9638
9639                 if (root_log_pinned) {
9640                         btrfs_end_log_trans(root);
9641                         root_log_pinned = false;
9642                 }
9643                 if (dest_log_pinned) {
9644                         btrfs_end_log_trans(dest);
9645                         dest_log_pinned = false;
9646                 }
9647         }
9648         ret = btrfs_end_transaction(trans);
9649 out_notrans:
9650         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9651                 up_read(&fs_info->subvol_sem);
9652         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9653                 up_read(&fs_info->subvol_sem);
9654
9655         return ret;
9656 }
9657
9658 static int btrfs_whiteout_for_rename(struct btrfs_trans_handle *trans,
9659                                      struct btrfs_root *root,
9660                                      struct inode *dir,
9661                                      struct dentry *dentry)
9662 {
9663         int ret;
9664         struct inode *inode;
9665         u64 objectid;
9666         u64 index;
9667
9668         ret = btrfs_find_free_ino(root, &objectid);
9669         if (ret)
9670                 return ret;
9671
9672         inode = btrfs_new_inode(trans, root, dir,
9673                                 dentry->d_name.name,
9674                                 dentry->d_name.len,
9675                                 btrfs_ino(BTRFS_I(dir)),
9676                                 objectid,
9677                                 S_IFCHR | WHITEOUT_MODE,
9678                                 &index);
9679
9680         if (IS_ERR(inode)) {
9681                 ret = PTR_ERR(inode);
9682                 return ret;
9683         }
9684
9685         inode->i_op = &btrfs_special_inode_operations;
9686         init_special_inode(inode, inode->i_mode,
9687                 WHITEOUT_DEV);
9688
9689         ret = btrfs_init_inode_security(trans, inode, dir,
9690                                 &dentry->d_name);
9691         if (ret)
9692                 goto out;
9693
9694         ret = btrfs_add_nondir(trans, dir, dentry,
9695                                 inode, 0, index);
9696         if (ret)
9697                 goto out;
9698
9699         ret = btrfs_update_inode(trans, root, inode);
9700 out:
9701         unlock_new_inode(inode);
9702         if (ret)
9703                 inode_dec_link_count(inode);
9704         iput(inode);
9705
9706         return ret;
9707 }
9708
9709 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
9710                            struct inode *new_dir, struct dentry *new_dentry,
9711                            unsigned int flags)
9712 {
9713         struct btrfs_fs_info *fs_info = btrfs_sb(old_dir->i_sb);
9714         struct btrfs_trans_handle *trans;
9715         unsigned int trans_num_items;
9716         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9717         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9718         struct inode *new_inode = d_inode(new_dentry);
9719         struct inode *old_inode = d_inode(old_dentry);
9720         u64 index = 0;
9721         u64 root_objectid;
9722         int ret;
9723         u64 old_ino = btrfs_ino(BTRFS_I(old_inode));
9724         bool log_pinned = false;
9725
9726         if (btrfs_ino(BTRFS_I(new_dir)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
9727                 return -EPERM;
9728
9729         /* we only allow rename subvolume link between subvolumes */
9730         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9731                 return -EXDEV;
9732
9733         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
9734             (new_inode && btrfs_ino(BTRFS_I(new_inode)) == BTRFS_FIRST_FREE_OBJECTID))
9735                 return -ENOTEMPTY;
9736
9737         if (S_ISDIR(old_inode->i_mode) && new_inode &&
9738             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
9739                 return -ENOTEMPTY;
9740
9741
9742         /* check for collisions, even if the  name isn't there */
9743         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
9744                              new_dentry->d_name.name,
9745                              new_dentry->d_name.len);
9746
9747         if (ret) {
9748                 if (ret == -EEXIST) {
9749                         /* we shouldn't get
9750                          * eexist without a new_inode */
9751                         if (WARN_ON(!new_inode)) {
9752                                 return ret;
9753                         }
9754                 } else {
9755                         /* maybe -EOVERFLOW */
9756                         return ret;
9757                 }
9758         }
9759         ret = 0;
9760
9761         /*
9762          * we're using rename to replace one file with another.  Start IO on it
9763          * now so  we don't add too much work to the end of the transaction
9764          */
9765         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
9766                 filemap_flush(old_inode->i_mapping);
9767
9768         /* close the racy window with snapshot create/destroy ioctl */
9769         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9770                 down_read(&fs_info->subvol_sem);
9771         /*
9772          * We want to reserve the absolute worst case amount of items.  So if
9773          * both inodes are subvols and we need to unlink them then that would
9774          * require 4 item modifications, but if they are both normal inodes it
9775          * would require 5 item modifications, so we'll assume they are normal
9776          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
9777          * should cover the worst case number of items we'll modify.
9778          * If our rename has the whiteout flag, we need more 5 units for the
9779          * new inode (1 inode item, 1 inode ref, 2 dir items and 1 xattr item
9780          * when selinux is enabled).
9781          */
9782         trans_num_items = 11;
9783         if (flags & RENAME_WHITEOUT)
9784                 trans_num_items += 5;
9785         trans = btrfs_start_transaction(root, trans_num_items);
9786         if (IS_ERR(trans)) {
9787                 ret = PTR_ERR(trans);
9788                 goto out_notrans;
9789         }
9790
9791         if (dest != root)
9792                 btrfs_record_root_in_trans(trans, dest);
9793
9794         ret = btrfs_set_inode_index(new_dir, &index);
9795         if (ret)
9796                 goto out_fail;
9797
9798         BTRFS_I(old_inode)->dir_index = 0ULL;
9799         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9800                 /* force full log commit if subvolume involved. */
9801                 btrfs_set_log_full_commit(fs_info, trans);
9802         } else {
9803                 btrfs_pin_log_trans(root);
9804                 log_pinned = true;
9805                 ret = btrfs_insert_inode_ref(trans, dest,
9806                                              new_dentry->d_name.name,
9807                                              new_dentry->d_name.len,
9808                                              old_ino,
9809                                              btrfs_ino(BTRFS_I(new_dir)), index);
9810                 if (ret)
9811                         goto out_fail;
9812         }
9813
9814         inode_inc_iversion(old_dir);
9815         inode_inc_iversion(new_dir);
9816         inode_inc_iversion(old_inode);
9817         old_dir->i_ctime = old_dir->i_mtime =
9818         new_dir->i_ctime = new_dir->i_mtime =
9819         old_inode->i_ctime = current_time(old_dir);
9820
9821         if (old_dentry->d_parent != new_dentry->d_parent)
9822                 btrfs_record_unlink_dir(trans, BTRFS_I(old_dir),
9823                                 BTRFS_I(old_inode), 1);
9824
9825         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9826                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9827                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
9828                                         old_dentry->d_name.name,
9829                                         old_dentry->d_name.len);
9830         } else {
9831                 ret = __btrfs_unlink_inode(trans, root, BTRFS_I(old_dir),
9832                                         BTRFS_I(d_inode(old_dentry)),
9833                                         old_dentry->d_name.name,
9834                                         old_dentry->d_name.len);
9835                 if (!ret)
9836                         ret = btrfs_update_inode(trans, root, old_inode);
9837         }
9838         if (ret) {
9839                 btrfs_abort_transaction(trans, ret);
9840                 goto out_fail;
9841         }
9842
9843         if (new_inode) {
9844                 inode_inc_iversion(new_inode);
9845                 new_inode->i_ctime = current_time(new_inode);
9846                 if (unlikely(btrfs_ino(BTRFS_I(new_inode)) ==
9847                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
9848                         root_objectid = BTRFS_I(new_inode)->location.objectid;
9849                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
9850                                                 root_objectid,
9851                                                 new_dentry->d_name.name,
9852                                                 new_dentry->d_name.len);
9853                         BUG_ON(new_inode->i_nlink == 0);
9854                 } else {
9855                         ret = btrfs_unlink_inode(trans, dest, BTRFS_I(new_dir),
9856                                                  BTRFS_I(d_inode(new_dentry)),
9857                                                  new_dentry->d_name.name,
9858                                                  new_dentry->d_name.len);
9859                 }
9860                 if (!ret && new_inode->i_nlink == 0)
9861                         ret = btrfs_orphan_add(trans, d_inode(new_dentry));
9862                 if (ret) {
9863                         btrfs_abort_transaction(trans, ret);
9864                         goto out_fail;
9865                 }
9866         }
9867
9868         ret = btrfs_add_link(trans, new_dir, old_inode,
9869                              new_dentry->d_name.name,
9870                              new_dentry->d_name.len, 0, index);
9871         if (ret) {
9872                 btrfs_abort_transaction(trans, ret);
9873                 goto out_fail;
9874         }
9875
9876         if (old_inode->i_nlink == 1)
9877                 BTRFS_I(old_inode)->dir_index = index;
9878
9879         if (log_pinned) {
9880                 struct dentry *parent = new_dentry->d_parent;
9881
9882                 btrfs_log_new_name(trans, BTRFS_I(old_inode), BTRFS_I(old_dir),
9883                                 parent);
9884                 btrfs_end_log_trans(root);
9885                 log_pinned = false;
9886         }
9887
9888         if (flags & RENAME_WHITEOUT) {
9889                 ret = btrfs_whiteout_for_rename(trans, root, old_dir,
9890                                                 old_dentry);
9891
9892                 if (ret) {
9893                         btrfs_abort_transaction(trans, ret);
9894                         goto out_fail;
9895                 }
9896         }
9897 out_fail:
9898         /*
9899          * If we have pinned the log and an error happened, we unpin tasks
9900          * trying to sync the log and force them to fallback to a transaction
9901          * commit if the log currently contains any of the inodes involved in
9902          * this rename operation (to ensure we do not persist a log with an
9903          * inconsistent state for any of these inodes or leading to any
9904          * inconsistencies when replayed). If the transaction was aborted, the
9905          * abortion reason is propagated to userspace when attempting to commit
9906          * the transaction. If the log does not contain any of these inodes, we
9907          * allow the tasks to sync it.
9908          */
9909         if (ret && log_pinned) {
9910                 if (btrfs_inode_in_log(BTRFS_I(old_dir), fs_info->generation) ||
9911                     btrfs_inode_in_log(BTRFS_I(new_dir), fs_info->generation) ||
9912                     btrfs_inode_in_log(BTRFS_I(old_inode), fs_info->generation) ||
9913                     (new_inode &&
9914                      btrfs_inode_in_log(BTRFS_I(new_inode), fs_info->generation)))
9915                         btrfs_set_log_full_commit(fs_info, trans);
9916
9917                 btrfs_end_log_trans(root);
9918                 log_pinned = false;
9919         }
9920         btrfs_end_transaction(trans);
9921 out_notrans:
9922         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9923                 up_read(&fs_info->subvol_sem);
9924
9925         return ret;
9926 }
9927
9928 static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
9929                          struct inode *new_dir, struct dentry *new_dentry,
9930                          unsigned int flags)
9931 {
9932         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
9933                 return -EINVAL;
9934
9935         if (flags & RENAME_EXCHANGE)
9936                 return btrfs_rename_exchange(old_dir, old_dentry, new_dir,
9937                                           new_dentry);
9938
9939         return btrfs_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
9940 }
9941
9942 static void btrfs_run_delalloc_work(struct btrfs_work *work)
9943 {
9944         struct btrfs_delalloc_work *delalloc_work;
9945         struct inode *inode;
9946
9947         delalloc_work = container_of(work, struct btrfs_delalloc_work,
9948                                      work);
9949         inode = delalloc_work->inode;
9950         filemap_flush(inode->i_mapping);
9951         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
9952                                 &BTRFS_I(inode)->runtime_flags))
9953                 filemap_flush(inode->i_mapping);
9954
9955         if (delalloc_work->delay_iput)
9956                 btrfs_add_delayed_iput(inode);
9957         else
9958                 iput(inode);
9959         complete(&delalloc_work->completion);
9960 }
9961
9962 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
9963                                                     int delay_iput)
9964 {
9965         struct btrfs_delalloc_work *work;
9966
9967         work = kmalloc(sizeof(*work), GFP_NOFS);
9968         if (!work)
9969                 return NULL;
9970
9971         init_completion(&work->completion);
9972         INIT_LIST_HEAD(&work->list);
9973         work->inode = inode;
9974         work->delay_iput = delay_iput;
9975         WARN_ON_ONCE(!inode);
9976         btrfs_init_work(&work->work, btrfs_flush_delalloc_helper,
9977                         btrfs_run_delalloc_work, NULL, NULL);
9978
9979         return work;
9980 }
9981
9982 void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
9983 {
9984         wait_for_completion(&work->completion);
9985         kfree(work);
9986 }
9987
9988 /*
9989  * some fairly slow code that needs optimization. This walks the list
9990  * of all the inodes with pending delalloc and forces them to disk.
9991  */
9992 static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
9993                                    int nr)
9994 {
9995         struct btrfs_inode *binode;
9996         struct inode *inode;
9997         struct btrfs_delalloc_work *work, *next;
9998         struct list_head works;
9999         struct list_head splice;
10000         int ret = 0;
10001
10002         INIT_LIST_HEAD(&works);
10003         INIT_LIST_HEAD(&splice);
10004
10005         mutex_lock(&root->delalloc_mutex);
10006         spin_lock(&root->delalloc_lock);
10007         list_splice_init(&root->delalloc_inodes, &splice);
10008         while (!list_empty(&splice)) {
10009                 binode = list_entry(splice.next, struct btrfs_inode,
10010                                     delalloc_inodes);
10011
10012                 list_move_tail(&binode->delalloc_inodes,
10013                                &root->delalloc_inodes);
10014                 inode = igrab(&binode->vfs_inode);
10015                 if (!inode) {
10016                         cond_resched_lock(&root->delalloc_lock);
10017                         continue;
10018                 }
10019                 spin_unlock(&root->delalloc_lock);
10020
10021                 work = btrfs_alloc_delalloc_work(inode, delay_iput);
10022                 if (!work) {
10023                         if (delay_iput)
10024                                 btrfs_add_delayed_iput(inode);
10025                         else
10026                                 iput(inode);
10027                         ret = -ENOMEM;
10028                         goto out;
10029                 }
10030                 list_add_tail(&work->list, &works);
10031                 btrfs_queue_work(root->fs_info->flush_workers,
10032                                  &work->work);
10033                 ret++;
10034                 if (nr != -1 && ret >= nr)
10035                         goto out;
10036                 cond_resched();
10037                 spin_lock(&root->delalloc_lock);
10038         }
10039         spin_unlock(&root->delalloc_lock);
10040
10041 out:
10042         list_for_each_entry_safe(work, next, &works, list) {
10043                 list_del_init(&work->list);
10044                 btrfs_wait_and_free_delalloc_work(work);
10045         }
10046
10047         if (!list_empty_careful(&splice)) {
10048                 spin_lock(&root->delalloc_lock);
10049                 list_splice_tail(&splice, &root->delalloc_inodes);
10050                 spin_unlock(&root->delalloc_lock);
10051         }
10052         mutex_unlock(&root->delalloc_mutex);
10053         return ret;
10054 }
10055
10056 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
10057 {
10058         struct btrfs_fs_info *fs_info = root->fs_info;
10059         int ret;
10060
10061         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
10062                 return -EROFS;
10063
10064         ret = __start_delalloc_inodes(root, delay_iput, -1);
10065         if (ret > 0)
10066                 ret = 0;
10067         /*
10068          * the filemap_flush will queue IO into the worker threads, but
10069          * we have to make sure the IO is actually started and that
10070          * ordered extents get created before we return
10071          */
10072         atomic_inc(&fs_info->async_submit_draining);
10073         while (atomic_read(&fs_info->nr_async_submits) ||
10074                atomic_read(&fs_info->async_delalloc_pages)) {
10075                 wait_event(fs_info->async_submit_wait,
10076                            (atomic_read(&fs_info->nr_async_submits) == 0 &&
10077                             atomic_read(&fs_info->async_delalloc_pages) == 0));
10078         }
10079         atomic_dec(&fs_info->async_submit_draining);
10080         return ret;
10081 }
10082
10083 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
10084                                int nr)
10085 {
10086         struct btrfs_root *root;
10087         struct list_head splice;
10088         int ret;
10089
10090         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
10091                 return -EROFS;
10092
10093         INIT_LIST_HEAD(&splice);
10094
10095         mutex_lock(&fs_info->delalloc_root_mutex);
10096         spin_lock(&fs_info->delalloc_root_lock);
10097         list_splice_init(&fs_info->delalloc_roots, &splice);
10098         while (!list_empty(&splice) && nr) {
10099                 root = list_first_entry(&splice, struct btrfs_root,
10100                                         delalloc_root);
10101                 root = btrfs_grab_fs_root(root);
10102                 BUG_ON(!root);
10103                 list_move_tail(&root->delalloc_root,
10104                                &fs_info->delalloc_roots);
10105                 spin_unlock(&fs_info->delalloc_root_lock);
10106
10107                 ret = __start_delalloc_inodes(root, delay_iput, nr);
10108                 btrfs_put_fs_root(root);
10109                 if (ret < 0)
10110                         goto out;
10111
10112                 if (nr != -1) {
10113                         nr -= ret;
10114                         WARN_ON(nr < 0);
10115                 }
10116                 spin_lock(&fs_info->delalloc_root_lock);
10117         }
10118         spin_unlock(&fs_info->delalloc_root_lock);
10119
10120         ret = 0;
10121         atomic_inc(&fs_info->async_submit_draining);
10122         while (atomic_read(&fs_info->nr_async_submits) ||
10123               atomic_read(&fs_info->async_delalloc_pages)) {
10124                 wait_event(fs_info->async_submit_wait,
10125                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
10126                     atomic_read(&fs_info->async_delalloc_pages) == 0));
10127         }
10128         atomic_dec(&fs_info->async_submit_draining);
10129 out:
10130         if (!list_empty_careful(&splice)) {
10131                 spin_lock(&fs_info->delalloc_root_lock);
10132                 list_splice_tail(&splice, &fs_info->delalloc_roots);
10133                 spin_unlock(&fs_info->delalloc_root_lock);
10134         }
10135         mutex_unlock(&fs_info->delalloc_root_mutex);
10136         return ret;
10137 }
10138
10139 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
10140                          const char *symname)
10141 {
10142         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
10143         struct btrfs_trans_handle *trans;
10144         struct btrfs_root *root = BTRFS_I(dir)->root;
10145         struct btrfs_path *path;
10146         struct btrfs_key key;
10147         struct inode *inode = NULL;
10148         int err;
10149         int drop_inode = 0;
10150         u64 objectid;
10151         u64 index = 0;
10152         int name_len;
10153         int datasize;
10154         unsigned long ptr;
10155         struct btrfs_file_extent_item *ei;
10156         struct extent_buffer *leaf;
10157
10158         name_len = strlen(symname);
10159         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info))
10160                 return -ENAMETOOLONG;
10161
10162         /*
10163          * 2 items for inode item and ref
10164          * 2 items for dir items
10165          * 1 item for updating parent inode item
10166          * 1 item for the inline extent item
10167          * 1 item for xattr if selinux is on
10168          */
10169         trans = btrfs_start_transaction(root, 7);
10170         if (IS_ERR(trans))
10171                 return PTR_ERR(trans);
10172
10173         err = btrfs_find_free_ino(root, &objectid);
10174         if (err)
10175                 goto out_unlock;
10176
10177         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
10178                                 dentry->d_name.len, btrfs_ino(BTRFS_I(dir)),
10179                                 objectid, S_IFLNK|S_IRWXUGO, &index);
10180         if (IS_ERR(inode)) {
10181                 err = PTR_ERR(inode);
10182                 goto out_unlock;
10183         }
10184
10185         /*
10186         * If the active LSM wants to access the inode during
10187         * d_instantiate it needs these. Smack checks to see
10188         * if the filesystem supports xattrs by looking at the
10189         * ops vector.
10190         */
10191         inode->i_fop = &btrfs_file_operations;
10192         inode->i_op = &btrfs_file_inode_operations;
10193         inode->i_mapping->a_ops = &btrfs_aops;
10194         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10195
10196         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
10197         if (err)
10198                 goto out_unlock_inode;
10199
10200         path = btrfs_alloc_path();
10201         if (!path) {
10202                 err = -ENOMEM;
10203                 goto out_unlock_inode;
10204         }
10205         key.objectid = btrfs_ino(BTRFS_I(inode));
10206         key.offset = 0;
10207         key.type = BTRFS_EXTENT_DATA_KEY;
10208         datasize = btrfs_file_extent_calc_inline_size(name_len);
10209         err = btrfs_insert_empty_item(trans, root, path, &key,
10210                                       datasize);
10211         if (err) {
10212                 btrfs_free_path(path);
10213                 goto out_unlock_inode;
10214         }
10215         leaf = path->nodes[0];
10216         ei = btrfs_item_ptr(leaf, path->slots[0],
10217                             struct btrfs_file_extent_item);
10218         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
10219         btrfs_set_file_extent_type(leaf, ei,
10220                                    BTRFS_FILE_EXTENT_INLINE);
10221         btrfs_set_file_extent_encryption(leaf, ei, 0);
10222         btrfs_set_file_extent_compression(leaf, ei, 0);
10223         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
10224         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
10225
10226         ptr = btrfs_file_extent_inline_start(ei);
10227         write_extent_buffer(leaf, symname, ptr, name_len);
10228         btrfs_mark_buffer_dirty(leaf);
10229         btrfs_free_path(path);
10230
10231         inode->i_op = &btrfs_symlink_inode_operations;
10232         inode_nohighmem(inode);
10233         inode->i_mapping->a_ops = &btrfs_symlink_aops;
10234         inode_set_bytes(inode, name_len);
10235         btrfs_i_size_write(inode, name_len);
10236         err = btrfs_update_inode(trans, root, inode);
10237         /*
10238          * Last step, add directory indexes for our symlink inode. This is the
10239          * last step to avoid extra cleanup of these indexes if an error happens
10240          * elsewhere above.
10241          */
10242         if (!err)
10243                 err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
10244         if (err) {
10245                 drop_inode = 1;
10246                 goto out_unlock_inode;
10247         }
10248
10249         unlock_new_inode(inode);
10250         d_instantiate(dentry, inode);
10251
10252 out_unlock:
10253         btrfs_end_transaction(trans);
10254         if (drop_inode) {
10255                 inode_dec_link_count(inode);
10256                 iput(inode);
10257         }
10258         btrfs_btree_balance_dirty(fs_info);
10259         return err;
10260
10261 out_unlock_inode:
10262         drop_inode = 1;
10263         unlock_new_inode(inode);
10264         goto out_unlock;
10265 }
10266
10267 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
10268                                        u64 start, u64 num_bytes, u64 min_size,
10269                                        loff_t actual_len, u64 *alloc_hint,
10270                                        struct btrfs_trans_handle *trans)
10271 {
10272         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
10273         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
10274         struct extent_map *em;
10275         struct btrfs_root *root = BTRFS_I(inode)->root;
10276         struct btrfs_key ins;
10277         u64 cur_offset = start;
10278         u64 i_size;
10279         u64 cur_bytes;
10280         u64 last_alloc = (u64)-1;
10281         int ret = 0;
10282         bool own_trans = true;
10283         u64 end = start + num_bytes - 1;
10284
10285         if (trans)
10286                 own_trans = false;
10287         while (num_bytes > 0) {
10288                 if (own_trans) {
10289                         trans = btrfs_start_transaction(root, 3);
10290                         if (IS_ERR(trans)) {
10291                                 ret = PTR_ERR(trans);
10292                                 break;
10293                         }
10294                 }
10295
10296                 cur_bytes = min_t(u64, num_bytes, SZ_256M);
10297                 cur_bytes = max(cur_bytes, min_size);
10298                 /*
10299                  * If we are severely fragmented we could end up with really
10300                  * small allocations, so if the allocator is returning small
10301                  * chunks lets make its job easier by only searching for those
10302                  * sized chunks.
10303                  */
10304                 cur_bytes = min(cur_bytes, last_alloc);
10305                 ret = btrfs_reserve_extent(root, cur_bytes, cur_bytes,
10306                                 min_size, 0, *alloc_hint, &ins, 1, 0);
10307                 if (ret) {
10308                         if (own_trans)
10309                                 btrfs_end_transaction(trans);
10310                         break;
10311                 }
10312                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
10313
10314                 last_alloc = ins.offset;
10315                 ret = insert_reserved_file_extent(trans, inode,
10316                                                   cur_offset, ins.objectid,
10317                                                   ins.offset, ins.offset,
10318                                                   ins.offset, 0, 0, 0,
10319                                                   BTRFS_FILE_EXTENT_PREALLOC);
10320                 if (ret) {
10321                         btrfs_free_reserved_extent(fs_info, ins.objectid,
10322                                                    ins.offset, 0);
10323                         btrfs_abort_transaction(trans, ret);
10324                         if (own_trans)
10325                                 btrfs_end_transaction(trans);
10326                         break;
10327                 }
10328
10329                 btrfs_drop_extent_cache(inode, cur_offset,
10330                                         cur_offset + ins.offset -1, 0);
10331
10332                 em = alloc_extent_map();
10333                 if (!em) {
10334                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
10335                                 &BTRFS_I(inode)->runtime_flags);
10336                         goto next;
10337                 }
10338
10339                 em->start = cur_offset;
10340                 em->orig_start = cur_offset;
10341                 em->len = ins.offset;
10342                 em->block_start = ins.objectid;
10343                 em->block_len = ins.offset;
10344                 em->orig_block_len = ins.offset;
10345                 em->ram_bytes = ins.offset;
10346                 em->bdev = fs_info->fs_devices->latest_bdev;
10347                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
10348                 em->generation = trans->transid;
10349
10350                 while (1) {
10351                         write_lock(&em_tree->lock);
10352                         ret = add_extent_mapping(em_tree, em, 1);
10353                         write_unlock(&em_tree->lock);
10354                         if (ret != -EEXIST)
10355                                 break;
10356                         btrfs_drop_extent_cache(inode, cur_offset,
10357                                                 cur_offset + ins.offset - 1,
10358                                                 0);
10359                 }
10360                 free_extent_map(em);
10361 next:
10362                 num_bytes -= ins.offset;
10363                 cur_offset += ins.offset;
10364                 *alloc_hint = ins.objectid + ins.offset;
10365
10366                 inode_inc_iversion(inode);
10367                 inode->i_ctime = current_time(inode);
10368                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
10369                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
10370                     (actual_len > inode->i_size) &&
10371                     (cur_offset > inode->i_size)) {
10372                         if (cur_offset > actual_len)
10373                                 i_size = actual_len;
10374                         else
10375                                 i_size = cur_offset;
10376                         i_size_write(inode, i_size);
10377                         btrfs_ordered_update_i_size(inode, i_size, NULL);
10378                 }
10379
10380                 ret = btrfs_update_inode(trans, root, inode);
10381
10382                 if (ret) {
10383                         btrfs_abort_transaction(trans, ret);
10384                         if (own_trans)
10385                                 btrfs_end_transaction(trans);
10386                         break;
10387                 }
10388
10389                 if (own_trans)
10390                         btrfs_end_transaction(trans);
10391         }
10392         if (cur_offset < end)
10393                 btrfs_free_reserved_data_space(inode, cur_offset,
10394                         end - cur_offset + 1);
10395         return ret;
10396 }
10397
10398 int btrfs_prealloc_file_range(struct inode *inode, int mode,
10399                               u64 start, u64 num_bytes, u64 min_size,
10400                               loff_t actual_len, u64 *alloc_hint)
10401 {
10402         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10403                                            min_size, actual_len, alloc_hint,
10404                                            NULL);
10405 }
10406
10407 int btrfs_prealloc_file_range_trans(struct inode *inode,
10408                                     struct btrfs_trans_handle *trans, int mode,
10409                                     u64 start, u64 num_bytes, u64 min_size,
10410                                     loff_t actual_len, u64 *alloc_hint)
10411 {
10412         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10413                                            min_size, actual_len, alloc_hint, trans);
10414 }
10415
10416 static int btrfs_set_page_dirty(struct page *page)
10417 {
10418         return __set_page_dirty_nobuffers(page);
10419 }
10420
10421 static int btrfs_permission(struct inode *inode, int mask)
10422 {
10423         struct btrfs_root *root = BTRFS_I(inode)->root;
10424         umode_t mode = inode->i_mode;
10425
10426         if (mask & MAY_WRITE &&
10427             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
10428                 if (btrfs_root_readonly(root))
10429                         return -EROFS;
10430                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
10431                         return -EACCES;
10432         }
10433         return generic_permission(inode, mask);
10434 }
10435
10436 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
10437 {
10438         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
10439         struct btrfs_trans_handle *trans;
10440         struct btrfs_root *root = BTRFS_I(dir)->root;
10441         struct inode *inode = NULL;
10442         u64 objectid;
10443         u64 index;
10444         int ret = 0;
10445
10446         /*
10447          * 5 units required for adding orphan entry
10448          */
10449         trans = btrfs_start_transaction(root, 5);
10450         if (IS_ERR(trans))
10451                 return PTR_ERR(trans);
10452
10453         ret = btrfs_find_free_ino(root, &objectid);
10454         if (ret)
10455                 goto out;
10456
10457         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
10458                         btrfs_ino(BTRFS_I(dir)), objectid, mode, &index);
10459         if (IS_ERR(inode)) {
10460                 ret = PTR_ERR(inode);
10461                 inode = NULL;
10462                 goto out;
10463         }
10464
10465         inode->i_fop = &btrfs_file_operations;
10466         inode->i_op = &btrfs_file_inode_operations;
10467
10468         inode->i_mapping->a_ops = &btrfs_aops;
10469         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10470
10471         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
10472         if (ret)
10473                 goto out_inode;
10474
10475         ret = btrfs_update_inode(trans, root, inode);
10476         if (ret)
10477                 goto out_inode;
10478         ret = btrfs_orphan_add(trans, inode);
10479         if (ret)
10480                 goto out_inode;
10481
10482         /*
10483          * We set number of links to 0 in btrfs_new_inode(), and here we set
10484          * it to 1 because d_tmpfile() will issue a warning if the count is 0,
10485          * through:
10486          *
10487          *    d_tmpfile() -> inode_dec_link_count() -> drop_nlink()
10488          */
10489         set_nlink(inode, 1);
10490         unlock_new_inode(inode);
10491         d_tmpfile(dentry, inode);
10492         mark_inode_dirty(inode);
10493
10494 out:
10495         btrfs_end_transaction(trans);
10496         if (ret)
10497                 iput(inode);
10498         btrfs_balance_delayed_items(fs_info);
10499         btrfs_btree_balance_dirty(fs_info);
10500         return ret;
10501
10502 out_inode:
10503         unlock_new_inode(inode);
10504         goto out;
10505
10506 }
10507
10508 static const struct inode_operations btrfs_dir_inode_operations = {
10509         .getattr        = btrfs_getattr,
10510         .lookup         = btrfs_lookup,
10511         .create         = btrfs_create,
10512         .unlink         = btrfs_unlink,
10513         .link           = btrfs_link,
10514         .mkdir          = btrfs_mkdir,
10515         .rmdir          = btrfs_rmdir,
10516         .rename         = btrfs_rename2,
10517         .symlink        = btrfs_symlink,
10518         .setattr        = btrfs_setattr,
10519         .mknod          = btrfs_mknod,
10520         .listxattr      = btrfs_listxattr,
10521         .permission     = btrfs_permission,
10522         .get_acl        = btrfs_get_acl,
10523         .set_acl        = btrfs_set_acl,
10524         .update_time    = btrfs_update_time,
10525         .tmpfile        = btrfs_tmpfile,
10526 };
10527 static const struct inode_operations btrfs_dir_ro_inode_operations = {
10528         .lookup         = btrfs_lookup,
10529         .permission     = btrfs_permission,
10530         .update_time    = btrfs_update_time,
10531 };
10532
10533 static const struct file_operations btrfs_dir_file_operations = {
10534         .llseek         = generic_file_llseek,
10535         .read           = generic_read_dir,
10536         .iterate_shared = btrfs_real_readdir,
10537         .unlocked_ioctl = btrfs_ioctl,
10538 #ifdef CONFIG_COMPAT
10539         .compat_ioctl   = btrfs_compat_ioctl,
10540 #endif
10541         .release        = btrfs_release_file,
10542         .fsync          = btrfs_sync_file,
10543 };
10544
10545 static const struct extent_io_ops btrfs_extent_io_ops = {
10546         .fill_delalloc = run_delalloc_range,
10547         .submit_bio_hook = btrfs_submit_bio_hook,
10548         .merge_bio_hook = btrfs_merge_bio_hook,
10549         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
10550         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
10551         .writepage_start_hook = btrfs_writepage_start_hook,
10552         .set_bit_hook = btrfs_set_bit_hook,
10553         .clear_bit_hook = btrfs_clear_bit_hook,
10554         .merge_extent_hook = btrfs_merge_extent_hook,
10555         .split_extent_hook = btrfs_split_extent_hook,
10556 };
10557
10558 /*
10559  * btrfs doesn't support the bmap operation because swapfiles
10560  * use bmap to make a mapping of extents in the file.  They assume
10561  * these extents won't change over the life of the file and they
10562  * use the bmap result to do IO directly to the drive.
10563  *
10564  * the btrfs bmap call would return logical addresses that aren't
10565  * suitable for IO and they also will change frequently as COW
10566  * operations happen.  So, swapfile + btrfs == corruption.
10567  *
10568  * For now we're avoiding this by dropping bmap.
10569  */
10570 static const struct address_space_operations btrfs_aops = {
10571         .readpage       = btrfs_readpage,
10572         .writepage      = btrfs_writepage,
10573         .writepages     = btrfs_writepages,
10574         .readpages      = btrfs_readpages,
10575         .direct_IO      = btrfs_direct_IO,
10576         .invalidatepage = btrfs_invalidatepage,
10577         .releasepage    = btrfs_releasepage,
10578         .set_page_dirty = btrfs_set_page_dirty,
10579         .error_remove_page = generic_error_remove_page,
10580 };
10581
10582 static const struct address_space_operations btrfs_symlink_aops = {
10583         .readpage       = btrfs_readpage,
10584         .writepage      = btrfs_writepage,
10585         .invalidatepage = btrfs_invalidatepage,
10586         .releasepage    = btrfs_releasepage,
10587 };
10588
10589 static const struct inode_operations btrfs_file_inode_operations = {
10590         .getattr        = btrfs_getattr,
10591         .setattr        = btrfs_setattr,
10592         .listxattr      = btrfs_listxattr,
10593         .permission     = btrfs_permission,
10594         .fiemap         = btrfs_fiemap,
10595         .get_acl        = btrfs_get_acl,
10596         .set_acl        = btrfs_set_acl,
10597         .update_time    = btrfs_update_time,
10598 };
10599 static const struct inode_operations btrfs_special_inode_operations = {
10600         .getattr        = btrfs_getattr,
10601         .setattr        = btrfs_setattr,
10602         .permission     = btrfs_permission,
10603         .listxattr      = btrfs_listxattr,
10604         .get_acl        = btrfs_get_acl,
10605         .set_acl        = btrfs_set_acl,
10606         .update_time    = btrfs_update_time,
10607 };
10608 static const struct inode_operations btrfs_symlink_inode_operations = {
10609         .get_link       = page_get_link,
10610         .getattr        = btrfs_getattr,
10611         .setattr        = btrfs_setattr,
10612         .permission     = btrfs_permission,
10613         .listxattr      = btrfs_listxattr,
10614         .update_time    = btrfs_update_time,
10615 };
10616
10617 const struct dentry_operations btrfs_dentry_operations = {
10618         .d_delete       = btrfs_dentry_delete,
10619         .d_release      = btrfs_dentry_release,
10620 };