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/statfs.h>
  34 #include <linux/compat.h>
  35 #include <linux/bit_spinlock.h>
  36 #include <linux/xattr.h>
  37 #include <linux/posix_acl.h>
  38 #include <linux/falloc.h>
  39 #include <linux/slab.h>
  40 #include <linux/ratelimit.h>
  41 #include <linux/mount.h>
  42 #include <linux/btrfs.h>
  43 #include <linux/blkdev.h>
  44 #include <linux/posix_acl_xattr.h>
  45 #include <linux/uio.h>
  46 #include "ctree.h"
  47 #include "disk-io.h"
  48 #include "transaction.h"
  49 #include "btrfs_inode.h"
  50 #include "print-tree.h"
  51 #include "ordered-data.h"
  52 #include "xattr.h"
  53 #include "tree-log.h"
  54 #include "volumes.h"
  55 #include "compression.h"
  56 #include "locking.h"
  57 #include "free-space-cache.h"
  58 #include "inode-map.h"
  59 #include "backref.h"
  60 #include "hash.h"
  61 #include "props.h"
  62 #include "qgroup.h"
  63
  64 struct btrfs_iget_args {
  65         struct btrfs_key *location;
  66         struct btrfs_root *root;
  67 };
  68
  69 static const struct inode_operations btrfs_dir_inode_operations;
  70 static const struct inode_operations btrfs_symlink_inode_operations;
  71 static const struct inode_operations btrfs_dir_ro_inode_operations;
  72 static const struct inode_operations btrfs_special_inode_operations;
  73 static const struct inode_operations btrfs_file_inode_operations;
  74 static const struct address_space_operations btrfs_aops;
  75 static const struct address_space_operations btrfs_symlink_aops;
  76 static const struct file_operations btrfs_dir_file_operations;
  77 static struct extent_io_ops btrfs_extent_io_ops;
  78
  79 static struct kmem_cache *btrfs_inode_cachep;
  80 static struct kmem_cache *btrfs_delalloc_work_cachep;
  81 struct kmem_cache *btrfs_trans_handle_cachep;
  82 struct kmem_cache *btrfs_transaction_cachep;
  83 struct kmem_cache *btrfs_path_cachep;
  84 struct kmem_cache *btrfs_free_space_cachep;
  85
  86 #define S_SHIFT 12
  87 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  88         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  89         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  90         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  91         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  92         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  93         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  94         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  95 };
  96
  97 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
  98 static int btrfs_truncate(struct inode *inode);
  99 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
 100 static noinline int cow_file_range(struct inode *inode,
 101                                    struct page *locked_page,
 102                                    u64 start, u64 end, int *page_started,
 103                                    unsigned long *nr_written, int unlock);
 104 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
 105                                            u64 len, u64 orig_start,
 106                                            u64 block_start, u64 block_len,
 107                                            u64 orig_block_len, u64 ram_bytes,
 108                                            int type);
 109
 110 static int btrfs_dirty_inode(struct inode *inode);
 111
 112 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 113 void btrfs_test_inode_set_ops(struct inode *inode)
 114 {
 115         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
 116 }
 117 #endif
 118
 119 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 120                                      struct inode *inode,  struct inode *dir,
 121                                      const struct qstr *qstr)
 122 {
 123         int err;
 124
 125         err = btrfs_init_acl(trans, inode, dir);
 126         if (!err)
 127                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 128         return err;
 129 }
 130
 131 /*
 132  * this does all the hard work for inserting an inline extent into
 133  * the btree.  The caller should have done a btrfs_drop_extents so that
 134  * no overlapping inline items exist in the btree
 135  */
 136 static int insert_inline_extent(struct btrfs_trans_handle *trans,
 137                                 struct btrfs_path *path, int extent_inserted,
 138                                 struct btrfs_root *root, struct inode *inode,
 139                                 u64 start, size_t size, size_t compressed_size,
 140                                 int compress_type,
 141                                 struct page **compressed_pages)
 142 {
 143         struct extent_buffer *leaf;
 144         struct page *page = NULL;
 145         char *kaddr;
 146         unsigned long ptr;
 147         struct btrfs_file_extent_item *ei;
 148         int err = 0;
 149         int ret;
 150         size_t cur_size = size;
 151         unsigned long offset;
 152
 153         if (compressed_size && compressed_pages)
 154                 cur_size = compressed_size;
 155
 156         inode_add_bytes(inode, size);
 157
 158         if (!extent_inserted) {
 159                 struct btrfs_key key;
 160                 size_t datasize;
 161
 162                 key.objectid = btrfs_ino(inode);
 163                 key.offset = start;
 164                 key.type = BTRFS_EXTENT_DATA_KEY;
 165
 166                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 167                 path->leave_spinning = 1;
 168                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 169                                               datasize);
 170                 if (ret) {
 171                         err = ret;
 172                         goto fail;
 173                 }
 174         }
 175         leaf = path->nodes[0];
 176         ei = btrfs_item_ptr(leaf, path->slots[0],
 177                             struct btrfs_file_extent_item);
 178         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 179         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 180         btrfs_set_file_extent_encryption(leaf, ei, 0);
 181         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 182         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 183         ptr = btrfs_file_extent_inline_start(ei);
 184
 185         if (compress_type != BTRFS_COMPRESS_NONE) {
 186                 struct page *cpage;
 187                 int i = 0;
 188                 while (compressed_size > 0) {
 189                         cpage = compressed_pages[i];
 190                         cur_size = min_t(unsigned long, compressed_size,
 191                                        PAGE_CACHE_SIZE);
 192
 193                         kaddr = kmap_atomic(cpage);
 194                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 195                         kunmap_atomic(kaddr);
 196
 197                         i++;
 198                         ptr += cur_size;
 199                         compressed_size -= cur_size;
 200                 }
 201                 btrfs_set_file_extent_compression(leaf, ei,
 202                                                   compress_type);
 203         } else {
 204                 page = find_get_page(inode->i_mapping,
 205                                      start >> PAGE_CACHE_SHIFT);
 206                 btrfs_set_file_extent_compression(leaf, ei, 0);
 207                 kaddr = kmap_atomic(page);
 208                 offset = start & (PAGE_CACHE_SIZE - 1);
 209                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 210                 kunmap_atomic(kaddr);
 211                 page_cache_release(page);
 212         }
 213         btrfs_mark_buffer_dirty(leaf);
 214         btrfs_release_path(path);
 215
 216         /*
 217          * we're an inline extent, so nobody can
 218          * extend the file past i_size without locking
 219          * a page we already have locked.
 220          *
 221          * We must do any isize and inode updates
 222          * before we unlock the pages.  Otherwise we
 223          * could end up racing with unlink.
 224          */
 225         BTRFS_I(inode)->disk_i_size = inode->i_size;
 226         ret = btrfs_update_inode(trans, root, inode);
 227
 228         return ret;
 229 fail:
 230         return err;
 231 }
 232
 233
 234 /*
 235  * conditionally insert an inline extent into the file.  This
 236  * does the checks required to make sure the data is small enough
 237  * to fit as an inline extent.
 238  */
 239 static noinline int cow_file_range_inline(struct btrfs_root *root,
 240                                           struct inode *inode, u64 start,
 241                                           u64 end, size_t compressed_size,
 242                                           int compress_type,
 243                                           struct page **compressed_pages)
 244 {
 245         struct btrfs_trans_handle *trans;
 246         u64 isize = i_size_read(inode);
 247         u64 actual_end = min(end + 1, isize);
 248         u64 inline_len = actual_end - start;
 249         u64 aligned_end = ALIGN(end, root->sectorsize);
 250         u64 data_len = inline_len;
 251         int ret;
 252         struct btrfs_path *path;
 253         int extent_inserted = 0;
 254         u32 extent_item_size;
 255
 256         if (compressed_size)
 257                 data_len = compressed_size;
 258
 259         if (start > 0 ||
 260             actual_end > PAGE_CACHE_SIZE ||
 261             data_len > BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 262             (!compressed_size &&
 263             (actual_end & (root->sectorsize - 1)) == 0) ||
 264             end + 1 < isize ||
 265             data_len > root->fs_info->max_inline) {
 266                 return 1;
 267         }
 268
 269         path = btrfs_alloc_path();
 270         if (!path)
 271                 return -ENOMEM;
 272
 273         trans = btrfs_join_transaction(root);
 274         if (IS_ERR(trans)) {
 275                 btrfs_free_path(path);
 276                 return PTR_ERR(trans);
 277         }
 278         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 279
 280         if (compressed_size && compressed_pages)
 281                 extent_item_size = btrfs_file_extent_calc_inline_size(
 282                    compressed_size);
 283         else
 284                 extent_item_size = btrfs_file_extent_calc_inline_size(
 285                     inline_len);
 286
 287         ret = __btrfs_drop_extents(trans, root, inode, path,
 288                                    start, aligned_end, NULL,
 289                                    1, 1, extent_item_size, &extent_inserted);
 290         if (ret) {
 291                 btrfs_abort_transaction(trans, root, ret);
 292                 goto out;
 293         }
 294
 295         if (isize > actual_end)
 296                 inline_len = min_t(u64, isize, actual_end);
 297         ret = insert_inline_extent(trans, path, extent_inserted,
 298                                    root, inode, start,
 299                                    inline_len, compressed_size,
 300                                    compress_type, compressed_pages);
 301         if (ret && ret != -ENOSPC) {
 302                 btrfs_abort_transaction(trans, root, ret);
 303                 goto out;
 304         } else if (ret == -ENOSPC) {
 305                 ret = 1;
 306                 goto out;
 307         }
 308
 309         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 310         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 311         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 312 out:
 313         /*
 314          * Don't forget to free the reserved space, as for inlined extent
 315          * it won't count as data extent, free them directly here.
 316          * And at reserve time, it's always aligned to page size, so
 317          * just free one page here.
 318          */
 319         btrfs_qgroup_free_data(inode, 0, PAGE_CACHE_SIZE);
 320         btrfs_free_path(path);
 321         btrfs_end_transaction(trans, root);
 322         return ret;
 323 }
 324
 325 struct async_extent {
 326         u64 start;
 327         u64 ram_size;
 328         u64 compressed_size;
 329         struct page **pages;
 330         unsigned long nr_pages;
 331         int compress_type;
 332         struct list_head list;
 333 };
 334
 335 struct async_cow {
 336         struct inode *inode;
 337         struct btrfs_root *root;
 338         struct page *locked_page;
 339         u64 start;
 340         u64 end;
 341         struct list_head extents;
 342         struct btrfs_work work;
 343 };
 344
 345 static noinline int add_async_extent(struct async_cow *cow,
 346                                      u64 start, u64 ram_size,
 347                                      u64 compressed_size,
 348                                      struct page **pages,
 349                                      unsigned long nr_pages,
 350                                      int compress_type)
 351 {
 352         struct async_extent *async_extent;
 353
 354         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 355         BUG_ON(!async_extent); /* -ENOMEM */
 356         async_extent->start = start;
 357         async_extent->ram_size = ram_size;
 358         async_extent->compressed_size = compressed_size;
 359         async_extent->pages = pages;
 360         async_extent->nr_pages = nr_pages;
 361         async_extent->compress_type = compress_type;
 362         list_add_tail(&async_extent->list, &cow->extents);
 363         return 0;
 364 }
 365
 366 static inline int inode_need_compress(struct inode *inode)
 367 {
 368         struct btrfs_root *root = BTRFS_I(inode)->root;
 369
 370         /* force compress */
 371         if (btrfs_test_opt(root, FORCE_COMPRESS))
 372                 return 1;
 373         /* bad compression ratios */
 374         if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 375                 return 0;
 376         if (btrfs_test_opt(root, COMPRESS) ||
 377             BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS ||
 378             BTRFS_I(inode)->force_compress)
 379                 return 1;
 380         return 0;
 381 }
 382
 383 /*
 384  * we create compressed extents in two phases.  The first
 385  * phase compresses a range of pages that have already been
 386  * locked (both pages and state bits are locked).
 387  *
 388  * This is done inside an ordered work queue, and the compression
 389  * is spread across many cpus.  The actual IO submission is step
 390  * two, and the ordered work queue takes care of making sure that
 391  * happens in the same order things were put onto the queue by
 392  * writepages and friends.
 393  *
 394  * If this code finds it can't get good compression, it puts an
 395  * entry onto the work queue to write the uncompressed bytes.  This
 396  * makes sure that both compressed inodes and uncompressed inodes
 397  * are written in the same order that the flusher thread sent them
 398  * down.
 399  */
 400 static noinline void compress_file_range(struct inode *inode,
 401                                         struct page *locked_page,
 402                                         u64 start, u64 end,
 403                                         struct async_cow *async_cow,
 404                                         int *num_added)
 405 {
 406         struct btrfs_root *root = BTRFS_I(inode)->root;
 407         u64 num_bytes;
 408         u64 blocksize = root->sectorsize;
 409         u64 actual_end;
 410         u64 isize = i_size_read(inode);
 411         int ret = 0;
 412         struct page **pages = NULL;
 413         unsigned long nr_pages;
 414         unsigned long nr_pages_ret = 0;
 415         unsigned long total_compressed = 0;
 416         unsigned long total_in = 0;
 417         unsigned long max_compressed = 128 * 1024;
 418         unsigned long max_uncompressed = 128 * 1024;
 419         int i;
 420         int will_compress;
 421         int compress_type = root->fs_info->compress_type;
 422         int redirty = 0;
 423
 424         /* if this is a small write inside eof, kick off a defrag */
 425         if ((end - start + 1) < 16 * 1024 &&
 426             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 427                 btrfs_add_inode_defrag(NULL, inode);
 428
 429         actual_end = min_t(u64, isize, end + 1);
 430 again:
 431         will_compress = 0;
 432         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
 433         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
 434
 435         /*
 436          * we don't want to send crud past the end of i_size through
 437          * compression, that's just a waste of CPU time.  So, if the
 438          * end of the file is before the start of our current
 439          * requested range of bytes, we bail out to the uncompressed
 440          * cleanup code that can deal with all of this.
 441          *
 442          * It isn't really the fastest way to fix things, but this is a
 443          * very uncommon corner.
 444          */
 445         if (actual_end <= start)
 446                 goto cleanup_and_bail_uncompressed;
 447
 448         total_compressed = actual_end - start;
 449
 450         /*
 451          * skip compression for a small file range(<=blocksize) that
 452          * isn't an inline extent, since it dosen't save disk space at all.
 453          */
 454         if (total_compressed <= blocksize &&
 455            (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 456                 goto cleanup_and_bail_uncompressed;
 457
 458         /* we want to make sure that amount of ram required to uncompress
 459          * an extent is reasonable, so we limit the total size in ram
 460          * of a compressed extent to 128k.  This is a crucial number
 461          * because it also controls how easily we can spread reads across
 462          * cpus for decompression.
 463          *
 464          * We also want to make sure the amount of IO required to do
 465          * a random read is reasonably small, so we limit the size of
 466          * a compressed extent to 128k.
 467          */
 468         total_compressed = min(total_compressed, max_uncompressed);
 469         num_bytes = ALIGN(end - start + 1, blocksize);
 470         num_bytes = max(blocksize,  num_bytes);
 471         total_in = 0;
 472         ret = 0;
 473
 474         /*
 475          * we do compression for mount -o compress and when the
 476          * inode has not been flagged as nocompress.  This flag can
 477          * change at any time if we discover bad compression ratios.
 478          */
 479         if (inode_need_compress(inode)) {
 480                 WARN_ON(pages);
 481                 pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
 482                 if (!pages) {
 483                         /* just bail out to the uncompressed code */
 484                         goto cont;
 485                 }
 486
 487                 if (BTRFS_I(inode)->force_compress)
 488                         compress_type = BTRFS_I(inode)->force_compress;
 489
 490                 /*
 491                  * we need to call clear_page_dirty_for_io on each
 492                  * page in the range.  Otherwise applications with the file
 493                  * mmap'd can wander in and change the page contents while
 494                  * we are compressing them.
 495                  *
 496                  * If the compression fails for any reason, we set the pages
 497                  * dirty again later on.
 498                  */
 499                 extent_range_clear_dirty_for_io(inode, start, end);
 500                 redirty = 1;
 501                 ret = btrfs_compress_pages(compress_type,
 502                                            inode->i_mapping, start,
 503                                            total_compressed, pages,
 504                                            nr_pages, &nr_pages_ret,
 505                                            &total_in,
 506                                            &total_compressed,
 507                                            max_compressed);
 508
 509                 if (!ret) {
 510                         unsigned long offset = total_compressed &
 511                                 (PAGE_CACHE_SIZE - 1);
 512                         struct page *page = pages[nr_pages_ret - 1];
 513                         char *kaddr;
 514
 515                         /* zero the tail end of the last page, we might be
 516                          * sending it down to disk
 517                          */
 518                         if (offset) {
 519                                 kaddr = kmap_atomic(page);
 520                                 memset(kaddr + offset, 0,
 521                                        PAGE_CACHE_SIZE - offset);
 522                                 kunmap_atomic(kaddr);
 523                         }
 524                         will_compress = 1;
 525                 }
 526         }
 527 cont:
 528         if (start == 0) {
 529                 /* lets try to make an inline extent */
 530                 if (ret || total_in < (actual_end - start)) {
 531                         /* we didn't compress the entire range, try
 532                          * to make an uncompressed inline extent.
 533                          */
 534                         ret = cow_file_range_inline(root, inode, start, end,
 535                                                     0, 0, NULL);
 536                 } else {
 537                         /* try making a compressed inline extent */
 538                         ret = cow_file_range_inline(root, inode, start, end,
 539                                                     total_compressed,
 540                                                     compress_type, pages);
 541                 }
 542                 if (ret <= 0) {
 543                         unsigned long clear_flags = EXTENT_DELALLOC |
 544                                 EXTENT_DEFRAG;
 545                         unsigned long page_error_op;
 546
 547                         clear_flags |= (ret < 0) ? EXTENT_DO_ACCOUNTING : 0;
 548                         page_error_op = ret < 0 ? PAGE_SET_ERROR : 0;
 549
 550                         /*
 551                          * inline extent creation worked or returned error,
 552                          * we don't need to create any more async work items.
 553                          * Unlock and free up our temp pages.
 554                          */
 555                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 556                                                      clear_flags, PAGE_UNLOCK |
 557                                                      PAGE_CLEAR_DIRTY |
 558                                                      PAGE_SET_WRITEBACK |
 559                                                      page_error_op |
 560                                                      PAGE_END_WRITEBACK);
 561                         goto free_pages_out;
 562                 }
 563         }
 564
 565         if (will_compress) {
 566                 /*
 567                  * we aren't doing an inline extent round the compressed size
 568                  * up to a block size boundary so the allocator does sane
 569                  * things
 570                  */
 571                 total_compressed = ALIGN(total_compressed, blocksize);
 572
 573                 /*
 574                  * one last check to make sure the compression is really a
 575                  * win, compare the page count read with the blocks on disk
 576                  */
 577                 total_in = ALIGN(total_in, PAGE_CACHE_SIZE);
 578                 if (total_compressed >= total_in) {
 579                         will_compress = 0;
 580                 } else {
 581                         num_bytes = total_in;
 582                 }
 583         }
 584         if (!will_compress && pages) {
 585                 /*
 586                  * the compression code ran but failed to make things smaller,
 587                  * free any pages it allocated and our page pointer array
 588                  */
 589                 for (i = 0; i < nr_pages_ret; i++) {
 590                         WARN_ON(pages[i]->mapping);
 591                         page_cache_release(pages[i]);
 592                 }
 593                 kfree(pages);
 594                 pages = NULL;
 595                 total_compressed = 0;
 596                 nr_pages_ret = 0;
 597
 598                 /* flag the file so we don't compress in the future */
 599                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
 600                     !(BTRFS_I(inode)->force_compress)) {
 601                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 602                 }
 603         }
 604         if (will_compress) {
 605                 *num_added += 1;
 606
 607                 /* the async work queues will take care of doing actual
 608                  * allocation on disk for these compressed pages,
 609                  * and will submit them to the elevator.
 610                  */
 611                 add_async_extent(async_cow, start, num_bytes,
 612                                  total_compressed, pages, nr_pages_ret,
 613                                  compress_type);
 614
 615                 if (start + num_bytes < end) {
 616                         start += num_bytes;
 617                         pages = NULL;
 618                         cond_resched();
 619                         goto again;
 620                 }
 621         } else {
 622 cleanup_and_bail_uncompressed:
 623                 /*
 624                  * No compression, but we still need to write the pages in
 625                  * the file we've been given so far.  redirty the locked
 626                  * page if it corresponds to our extent and set things up
 627                  * for the async work queue to run cow_file_range to do
 628                  * the normal delalloc dance
 629                  */
 630                 if (page_offset(locked_page) >= start &&
 631                     page_offset(locked_page) <= end) {
 632                         __set_page_dirty_nobuffers(locked_page);
 633                         /* unlocked later on in the async handlers */
 634                 }
 635                 if (redirty)
 636                         extent_range_redirty_for_io(inode, start, end);
 637                 add_async_extent(async_cow, start, end - start + 1,
 638                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
 639                 *num_added += 1;
 640         }
 641
 642         return;
 643
 644 free_pages_out:
 645         for (i = 0; i < nr_pages_ret; i++) {
 646                 WARN_ON(pages[i]->mapping);
 647                 page_cache_release(pages[i]);
 648         }
 649         kfree(pages);
 650 }
 651
 652 static void free_async_extent_pages(struct async_extent *async_extent)
 653 {
 654         int i;
 655
 656         if (!async_extent->pages)
 657                 return;
 658
 659         for (i = 0; i < async_extent->nr_pages; i++) {
 660                 WARN_ON(async_extent->pages[i]->mapping);
 661                 page_cache_release(async_extent->pages[i]);
 662         }
 663         kfree(async_extent->pages);
 664         async_extent->nr_pages = 0;
 665         async_extent->pages = NULL;
 666 }
 667
 668 /*
 669  * phase two of compressed writeback.  This is the ordered portion
 670  * of the code, which only gets called in the order the work was
 671  * queued.  We walk all the async extents created by compress_file_range
 672  * and send them down to the disk.
 673  */
 674 static noinline void submit_compressed_extents(struct inode *inode,
 675                                               struct async_cow *async_cow)
 676 {
 677         struct async_extent *async_extent;
 678         u64 alloc_hint = 0;
 679         struct btrfs_key ins;
 680         struct extent_map *em;
 681         struct btrfs_root *root = BTRFS_I(inode)->root;
 682         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 683         struct extent_io_tree *io_tree;
 684         int ret = 0;
 685
 686 again:
 687         while (!list_empty(&async_cow->extents)) {
 688                 async_extent = list_entry(async_cow->extents.next,
 689                                           struct async_extent, list);
 690                 list_del(&async_extent->list);
 691
 692                 io_tree = &BTRFS_I(inode)->io_tree;
 693
 694 retry:
 695                 /* did the compression code fall back to uncompressed IO? */
 696                 if (!async_extent->pages) {
 697                         int page_started = 0;
 698                         unsigned long nr_written = 0;
 699
 700                         lock_extent(io_tree, async_extent->start,
 701                                          async_extent->start +
 702                                          async_extent->ram_size - 1);
 703
 704                         /* allocate blocks */
 705                         ret = cow_file_range(inode, async_cow->locked_page,
 706                                              async_extent->start,
 707                                              async_extent->start +
 708                                              async_extent->ram_size - 1,
 709                                              &page_started, &nr_written, 0);
 710
 711                         /* JDM XXX */
 712
 713                         /*
 714                          * if page_started, cow_file_range inserted an
 715                          * inline extent and took care of all the unlocking
 716                          * and IO for us.  Otherwise, we need to submit
 717                          * all those pages down to the drive.
 718                          */
 719                         if (!page_started && !ret)
 720                                 extent_write_locked_range(io_tree,
 721                                                   inode, async_extent->start,
 722                                                   async_extent->start +
 723                                                   async_extent->ram_size - 1,
 724                                                   btrfs_get_extent,
 725                                                   WB_SYNC_ALL);
 726                         else if (ret)
 727                                 unlock_page(async_cow->locked_page);
 728                         kfree(async_extent);
 729                         cond_resched();
 730                         continue;
 731                 }
 732
 733                 lock_extent(io_tree, async_extent->start,
 734                             async_extent->start + async_extent->ram_size - 1);
 735
 736                 ret = btrfs_reserve_extent(root,
 737                                            async_extent->compressed_size,
 738                                            async_extent->compressed_size,
 739                                            0, alloc_hint, &ins, 1, 1);
 740                 if (ret) {
 741                         free_async_extent_pages(async_extent);
 742
 743                         if (ret == -ENOSPC) {
 744                                 unlock_extent(io_tree, async_extent->start,
 745                                               async_extent->start +
 746                                               async_extent->ram_size - 1);
 747
 748                                 /*
 749                                  * we need to redirty the pages if we decide to
 750                                  * fallback to uncompressed IO, otherwise we
 751                                  * will not submit these pages down to lower
 752                                  * layers.
 753                                  */
 754                                 extent_range_redirty_for_io(inode,
 755                                                 async_extent->start,
 756                                                 async_extent->start +
 757                                                 async_extent->ram_size - 1);
 758
 759                                 goto retry;
 760                         }
 761                         goto out_free;
 762                 }
 763                 /*
 764                  * here we're doing allocation and writeback of the
 765                  * compressed pages
 766                  */
 767                 btrfs_drop_extent_cache(inode, async_extent->start,
 768                                         async_extent->start +
 769                                         async_extent->ram_size - 1, 0);
 770
 771                 em = alloc_extent_map();
 772                 if (!em) {
 773                         ret = -ENOMEM;
 774                         goto out_free_reserve;
 775                 }
 776                 em->start = async_extent->start;
 777                 em->len = async_extent->ram_size;
 778                 em->orig_start = em->start;
 779                 em->mod_start = em->start;
 780                 em->mod_len = em->len;
 781
 782                 em->block_start = ins.objectid;
 783                 em->block_len = ins.offset;
 784                 em->orig_block_len = ins.offset;
 785                 em->ram_bytes = async_extent->ram_size;
 786                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 787                 em->compress_type = async_extent->compress_type;
 788                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 789                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 790                 em->generation = -1;
 791
 792                 while (1) {
 793                         write_lock(&em_tree->lock);
 794                         ret = add_extent_mapping(em_tree, em, 1);
 795                         write_unlock(&em_tree->lock);
 796                         if (ret != -EEXIST) {
 797                                 free_extent_map(em);
 798                                 break;
 799                         }
 800                         btrfs_drop_extent_cache(inode, async_extent->start,
 801                                                 async_extent->start +
 802                                                 async_extent->ram_size - 1, 0);
 803                 }
 804
 805                 if (ret)
 806                         goto out_free_reserve;
 807
 808                 ret = btrfs_add_ordered_extent_compress(inode,
 809                                                 async_extent->start,
 810                                                 ins.objectid,
 811                                                 async_extent->ram_size,
 812                                                 ins.offset,
 813                                                 BTRFS_ORDERED_COMPRESSED,
 814                                                 async_extent->compress_type);
 815                 if (ret) {
 816                         btrfs_drop_extent_cache(inode, async_extent->start,
 817                                                 async_extent->start +
 818                                                 async_extent->ram_size - 1, 0);
 819                         goto out_free_reserve;
 820                 }
 821
 822                 /*
 823                  * clear dirty, set writeback and unlock the pages.
 824                  */
 825                 extent_clear_unlock_delalloc(inode, async_extent->start,
 826                                 async_extent->start +
 827                                 async_extent->ram_size - 1,
 828                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 829                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 830                                 PAGE_SET_WRITEBACK);
 831                 ret = btrfs_submit_compressed_write(inode,
 832                                     async_extent->start,
 833                                     async_extent->ram_size,
 834                                     ins.objectid,
 835                                     ins.offset, async_extent->pages,
 836                                     async_extent->nr_pages);
 837                 if (ret) {
 838                         struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 839                         struct page *p = async_extent->pages[0];
 840                         const u64 start = async_extent->start;
 841                         const u64 end = start + async_extent->ram_size - 1;
 842
 843                         p->mapping = inode->i_mapping;
 844                         tree->ops->writepage_end_io_hook(p, start, end,
 845                                                          NULL, 0);
 846                         p->mapping = NULL;
 847                         extent_clear_unlock_delalloc(inode, start, end, NULL, 0,
 848                                                      PAGE_END_WRITEBACK |
 849                                                      PAGE_SET_ERROR);
 850                         free_async_extent_pages(async_extent);
 851                 }
 852                 alloc_hint = ins.objectid + ins.offset;
 853                 kfree(async_extent);
 854                 cond_resched();
 855         }
 856         return;
 857 out_free_reserve:
 858         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
 859 out_free:
 860         extent_clear_unlock_delalloc(inode, async_extent->start,
 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, int *page_started,
 921                                    unsigned long *nr_written,
 922                                    int unlock)
 923 {
 924         struct btrfs_root *root = BTRFS_I(inode)->root;
 925         u64 alloc_hint = 0;
 926         u64 num_bytes;
 927         unsigned long ram_size;
 928         u64 disk_num_bytes;
 929         u64 cur_alloc_size;
 930         u64 blocksize = root->sectorsize;
 931         struct btrfs_key ins;
 932         struct extent_map *em;
 933         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 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         /* if this is a small write inside eof, kick off defrag */
 947         if (num_bytes < 64 * 1024 &&
 948             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 949                 btrfs_add_inode_defrag(NULL, inode);
 950
 951         if (start == 0) {
 952                 /* lets try to make an inline extent */
 953                 ret = cow_file_range_inline(root, inode, start, end, 0, 0,
 954                                             NULL);
 955                 if (ret == 0) {
 956                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 957                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 958                                      EXTENT_DEFRAG, PAGE_UNLOCK |
 959                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 960                                      PAGE_END_WRITEBACK);
 961
 962                         *nr_written = *nr_written +
 963                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
 964                         *page_started = 1;
 965                         goto out;
 966                 } else if (ret < 0) {
 967                         goto out_unlock;
 968                 }
 969         }
 970
 971         BUG_ON(disk_num_bytes >
 972                btrfs_super_total_bytes(root->fs_info->super_copy));
 973
 974         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 975         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 976
 977         while (disk_num_bytes > 0) {
 978                 unsigned long op;
 979
 980                 cur_alloc_size = disk_num_bytes;
 981                 ret = btrfs_reserve_extent(root, cur_alloc_size,
 982                                            root->sectorsize, 0, alloc_hint,
 983                                            &ins, 1, 1);
 984                 if (ret < 0)
 985                         goto out_unlock;
 986
 987                 em = alloc_extent_map();
 988                 if (!em) {
 989                         ret = -ENOMEM;
 990                         goto out_reserve;
 991                 }
 992                 em->start = start;
 993                 em->orig_start = em->start;
 994                 ram_size = ins.offset;
 995                 em->len = ins.offset;
 996                 em->mod_start = em->start;
 997                 em->mod_len = em->len;
 998
 999                 em->block_start = ins.objectid;
1000                 em->block_len = ins.offset;
1001                 em->orig_block_len = ins.offset;
1002                 em->ram_bytes = ram_size;
1003                 em->bdev = root->fs_info->fs_devices->latest_bdev;
1004                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
1005                 em->generation = -1;
1006
1007                 while (1) {
1008                         write_lock(&em_tree->lock);
1009                         ret = add_extent_mapping(em_tree, em, 1);
1010                         write_unlock(&em_tree->lock);
1011                         if (ret != -EEXIST) {
1012                                 free_extent_map(em);
1013                                 break;
1014                         }
1015                         btrfs_drop_extent_cache(inode, start,
1016                                                 start + ram_size - 1, 0);
1017                 }
1018                 if (ret)
1019                         goto out_reserve;
1020
1021                 cur_alloc_size = ins.offset;
1022                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
1023                                                ram_size, cur_alloc_size, 0);
1024                 if (ret)
1025                         goto out_drop_extent_cache;
1026
1027                 if (root->root_key.objectid ==
1028                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1029                         ret = btrfs_reloc_clone_csums(inode, start,
1030                                                       cur_alloc_size);
1031                         if (ret)
1032                                 goto out_drop_extent_cache;
1033                 }
1034
1035                 if (disk_num_bytes < cur_alloc_size)
1036                         break;
1037
1038                 /* we're not doing compressed IO, don't unlock the first
1039                  * page (which the caller expects to stay locked), don't
1040                  * clear any dirty bits and don't set any writeback bits
1041                  *
1042                  * Do set the Private2 bit so we know this page was properly
1043                  * setup for writepage
1044                  */
1045                 op = unlock ? PAGE_UNLOCK : 0;
1046                 op |= PAGE_SET_PRIVATE2;
1047
1048                 extent_clear_unlock_delalloc(inode, start,
1049                                              start + ram_size - 1, locked_page,
1050                                              EXTENT_LOCKED | EXTENT_DELALLOC,
1051                                              op);
1052                 disk_num_bytes -= cur_alloc_size;
1053                 num_bytes -= cur_alloc_size;
1054                 alloc_hint = ins.objectid + ins.offset;
1055                 start += cur_alloc_size;
1056         }
1057 out:
1058         return ret;
1059
1060 out_drop_extent_cache:
1061         btrfs_drop_extent_cache(inode, start, start + ram_size - 1, 0);
1062 out_reserve:
1063         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
1064 out_unlock:
1065         extent_clear_unlock_delalloc(inode, start, end, locked_page,
1066                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
1067                                      EXTENT_DELALLOC | EXTENT_DEFRAG,
1068                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
1069                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
1070         goto out;
1071 }
1072
1073 /*
1074  * work queue call back to started compression on a file and pages
1075  */
1076 static noinline void async_cow_start(struct btrfs_work *work)
1077 {
1078         struct async_cow *async_cow;
1079         int num_added = 0;
1080         async_cow = container_of(work, struct async_cow, work);
1081
1082         compress_file_range(async_cow->inode, async_cow->locked_page,
1083                             async_cow->start, async_cow->end, async_cow,
1084                             &num_added);
1085         if (num_added == 0) {
1086                 btrfs_add_delayed_iput(async_cow->inode);
1087                 async_cow->inode = NULL;
1088         }
1089 }
1090
1091 /*
1092  * work queue call back to submit previously compressed pages
1093  */
1094 static noinline void async_cow_submit(struct btrfs_work *work)
1095 {
1096         struct async_cow *async_cow;
1097         struct btrfs_root *root;
1098         unsigned long nr_pages;
1099
1100         async_cow = container_of(work, struct async_cow, work);
1101
1102         root = async_cow->root;
1103         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
1104                 PAGE_CACHE_SHIFT;
1105
1106         /*
1107          * atomic_sub_return implies a barrier for waitqueue_active
1108          */
1109         if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <
1110             5 * 1024 * 1024 &&
1111             waitqueue_active(&root->fs_info->async_submit_wait))
1112                 wake_up(&root->fs_info->async_submit_wait);
1113
1114         if (async_cow->inode)
1115                 submit_compressed_extents(async_cow->inode, async_cow);
1116 }
1117
1118 static noinline void async_cow_free(struct btrfs_work *work)
1119 {
1120         struct async_cow *async_cow;
1121         async_cow = container_of(work, struct async_cow, work);
1122         if (async_cow->inode)
1123                 btrfs_add_delayed_iput(async_cow->inode);
1124         kfree(async_cow);
1125 }
1126
1127 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1128                                 u64 start, u64 end, int *page_started,
1129                                 unsigned long *nr_written)
1130 {
1131         struct async_cow *async_cow;
1132         struct btrfs_root *root = BTRFS_I(inode)->root;
1133         unsigned long nr_pages;
1134         u64 cur_end;
1135         int limit = 10 * 1024 * 1024;
1136
1137         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1138                          1, 0, NULL, GFP_NOFS);
1139         while (start < end) {
1140                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1141                 BUG_ON(!async_cow); /* -ENOMEM */
1142                 async_cow->inode = igrab(inode);
1143                 async_cow->root = root;
1144                 async_cow->locked_page = locked_page;
1145                 async_cow->start = start;
1146
1147                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS &&
1148                     !btrfs_test_opt(root, FORCE_COMPRESS))
1149                         cur_end = end;
1150                 else
1151                         cur_end = min(end, start + 512 * 1024 - 1);
1152
1153                 async_cow->end = cur_end;
1154                 INIT_LIST_HEAD(&async_cow->extents);
1155
1156                 btrfs_init_work(&async_cow->work,
1157                                 btrfs_delalloc_helper,
1158                                 async_cow_start, async_cow_submit,
1159                                 async_cow_free);
1160
1161                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
1162                         PAGE_CACHE_SHIFT;
1163                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
1164
1165                 btrfs_queue_work(root->fs_info->delalloc_workers,
1166                                  &async_cow->work);
1167
1168                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1169                         wait_event(root->fs_info->async_submit_wait,
1170                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1171                             limit));
1172                 }
1173
1174                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1175                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1176                         wait_event(root->fs_info->async_submit_wait,
1177                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1178                            0));
1179                 }
1180
1181                 *nr_written += nr_pages;
1182                 start = cur_end + 1;
1183         }
1184         *page_started = 1;
1185         return 0;
1186 }
1187
1188 static noinline int csum_exist_in_range(struct btrfs_root *root,
1189                                         u64 bytenr, u64 num_bytes)
1190 {
1191         int ret;
1192         struct btrfs_ordered_sum *sums;
1193         LIST_HEAD(list);
1194
1195         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1196                                        bytenr + num_bytes - 1, &list, 0);
1197         if (ret == 0 && list_empty(&list))
1198                 return 0;
1199
1200         while (!list_empty(&list)) {
1201                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1202                 list_del(&sums->list);
1203                 kfree(sums);
1204         }
1205         return 1;
1206 }
1207
1208 /*
1209  * when nowcow writeback call back.  This checks for snapshots or COW copies
1210  * of the extents that exist in the file, and COWs the file as required.
1211  *
1212  * If no cow copies or snapshots exist, we write directly to the existing
1213  * blocks on disk
1214  */
1215 static noinline int run_delalloc_nocow(struct inode *inode,
1216                                        struct page *locked_page,
1217                               u64 start, u64 end, int *page_started, int force,
1218                               unsigned long *nr_written)
1219 {
1220         struct btrfs_root *root = BTRFS_I(inode)->root;
1221         struct btrfs_trans_handle *trans;
1222         struct extent_buffer *leaf;
1223         struct btrfs_path *path;
1224         struct btrfs_file_extent_item *fi;
1225         struct btrfs_key found_key;
1226         u64 cow_start;
1227         u64 cur_offset;
1228         u64 extent_end;
1229         u64 extent_offset;
1230         u64 disk_bytenr;
1231         u64 num_bytes;
1232         u64 disk_num_bytes;
1233         u64 ram_bytes;
1234         int extent_type;
1235         int ret, err;
1236         int type;
1237         int nocow;
1238         int check_prev = 1;
1239         bool nolock;
1240         u64 ino = btrfs_ino(inode);
1241
1242         path = btrfs_alloc_path();
1243         if (!path) {
1244                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1245                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1246                                              EXTENT_DO_ACCOUNTING |
1247                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1248                                              PAGE_CLEAR_DIRTY |
1249                                              PAGE_SET_WRITEBACK |
1250                                              PAGE_END_WRITEBACK);
1251                 return -ENOMEM;
1252         }
1253
1254         nolock = btrfs_is_free_space_inode(inode);
1255
1256         if (nolock)
1257                 trans = btrfs_join_transaction_nolock(root);
1258         else
1259                 trans = btrfs_join_transaction(root);
1260
1261         if (IS_ERR(trans)) {
1262                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1263                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1264                                              EXTENT_DO_ACCOUNTING |
1265                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1266                                              PAGE_CLEAR_DIRTY |
1267                                              PAGE_SET_WRITEBACK |
1268                                              PAGE_END_WRITEBACK);
1269                 btrfs_free_path(path);
1270                 return PTR_ERR(trans);
1271         }
1272
1273         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1274
1275         cow_start = (u64)-1;
1276         cur_offset = start;
1277         while (1) {
1278                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1279                                                cur_offset, 0);
1280                 if (ret < 0)
1281                         goto error;
1282                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1283                         leaf = path->nodes[0];
1284                         btrfs_item_key_to_cpu(leaf, &found_key,
1285                                               path->slots[0] - 1);
1286                         if (found_key.objectid == ino &&
1287                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1288                                 path->slots[0]--;
1289                 }
1290                 check_prev = 0;
1291 next_slot:
1292                 leaf = path->nodes[0];
1293                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1294                         ret = btrfs_next_leaf(root, path);
1295                         if (ret < 0)
1296                                 goto error;
1297                         if (ret > 0)
1298                                 break;
1299                         leaf = path->nodes[0];
1300                 }
1301
1302                 nocow = 0;
1303                 disk_bytenr = 0;
1304                 num_bytes = 0;
1305                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1306
1307                 if (found_key.objectid > ino ||
1308                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1309                     found_key.offset > end)
1310                         break;
1311
1312                 if (found_key.offset > cur_offset) {
1313                         extent_end = found_key.offset;
1314                         extent_type = 0;
1315                         goto out_check;
1316                 }
1317
1318                 fi = btrfs_item_ptr(leaf, path->slots[0],
1319                                     struct btrfs_file_extent_item);
1320                 extent_type = btrfs_file_extent_type(leaf, fi);
1321
1322                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1323                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1324                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1325                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1326                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1327                         extent_end = found_key.offset +
1328                                 btrfs_file_extent_num_bytes(leaf, fi);
1329                         disk_num_bytes =
1330                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1331                         if (extent_end <= start) {
1332                                 path->slots[0]++;
1333                                 goto next_slot;
1334                         }
1335                         if (disk_bytenr == 0)
1336                                 goto out_check;
1337                         if (btrfs_file_extent_compression(leaf, fi) ||
1338                             btrfs_file_extent_encryption(leaf, fi) ||
1339                             btrfs_file_extent_other_encoding(leaf, fi))
1340                                 goto out_check;
1341                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1342                                 goto out_check;
1343                         if (btrfs_extent_readonly(root, disk_bytenr))
1344                                 goto out_check;
1345                         if (btrfs_cross_ref_exist(trans, root, ino,
1346                                                   found_key.offset -
1347                                                   extent_offset, disk_bytenr))
1348                                 goto out_check;
1349                         disk_bytenr += extent_offset;
1350                         disk_bytenr += cur_offset - found_key.offset;
1351                         num_bytes = min(end + 1, extent_end) - cur_offset;
1352                         /*
1353                          * if there are pending snapshots for this root,
1354                          * we fall into common COW way.
1355                          */
1356                         if (!nolock) {
1357                                 err = btrfs_start_write_no_snapshoting(root);
1358                                 if (!err)
1359                                         goto out_check;
1360                         }
1361                         /*
1362                          * force cow if csum exists in the range.
1363                          * this ensure that csum for a given extent are
1364                          * either valid or do not exist.
1365                          */
1366                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1367                                 goto out_check;
1368                         nocow = 1;
1369                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1370                         extent_end = found_key.offset +
1371                                 btrfs_file_extent_inline_len(leaf,
1372                                                      path->slots[0], fi);
1373                         extent_end = ALIGN(extent_end, root->sectorsize);
1374                 } else {
1375                         BUG_ON(1);
1376                 }
1377 out_check:
1378                 if (extent_end <= start) {
1379                         path->slots[0]++;
1380                         if (!nolock && nocow)
1381                                 btrfs_end_write_no_snapshoting(root);
1382                         goto next_slot;
1383                 }
1384                 if (!nocow) {
1385                         if (cow_start == (u64)-1)
1386                                 cow_start = cur_offset;
1387                         cur_offset = extent_end;
1388                         if (cur_offset > end)
1389                                 break;
1390                         path->slots[0]++;
1391                         goto next_slot;
1392                 }
1393
1394                 btrfs_release_path(path);
1395                 if (cow_start != (u64)-1) {
1396                         ret = cow_file_range(inode, locked_page,
1397                                              cow_start, found_key.offset - 1,
1398                                              page_started, nr_written, 1);
1399                         if (ret) {
1400                                 if (!nolock && nocow)
1401                                         btrfs_end_write_no_snapshoting(root);
1402                                 goto error;
1403                         }
1404                         cow_start = (u64)-1;
1405                 }
1406
1407                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1408                         struct extent_map *em;
1409                         struct extent_map_tree *em_tree;
1410                         em_tree = &BTRFS_I(inode)->extent_tree;
1411                         em = alloc_extent_map();
1412                         BUG_ON(!em); /* -ENOMEM */
1413                         em->start = cur_offset;
1414                         em->orig_start = found_key.offset - extent_offset;
1415                         em->len = num_bytes;
1416                         em->block_len = num_bytes;
1417                         em->block_start = disk_bytenr;
1418                         em->orig_block_len = disk_num_bytes;
1419                         em->ram_bytes = ram_bytes;
1420                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1421                         em->mod_start = em->start;
1422                         em->mod_len = em->len;
1423                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1424                         set_bit(EXTENT_FLAG_FILLING, &em->flags);
1425                         em->generation = -1;
1426                         while (1) {
1427                                 write_lock(&em_tree->lock);
1428                                 ret = add_extent_mapping(em_tree, em, 1);
1429                                 write_unlock(&em_tree->lock);
1430                                 if (ret != -EEXIST) {
1431                                         free_extent_map(em);
1432                                         break;
1433                                 }
1434                                 btrfs_drop_extent_cache(inode, em->start,
1435                                                 em->start + em->len - 1, 0);
1436                         }
1437                         type = BTRFS_ORDERED_PREALLOC;
1438                 } else {
1439                         type = BTRFS_ORDERED_NOCOW;
1440                 }
1441
1442                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1443                                                num_bytes, num_bytes, type);
1444                 BUG_ON(ret); /* -ENOMEM */
1445
1446                 if (root->root_key.objectid ==
1447                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1448                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1449                                                       num_bytes);
1450                         if (ret) {
1451                                 if (!nolock && nocow)
1452                                         btrfs_end_write_no_snapshoting(root);
1453                                 goto error;
1454                         }
1455                 }
1456
1457                 extent_clear_unlock_delalloc(inode, cur_offset,
1458                                              cur_offset + num_bytes - 1,
1459                                              locked_page, EXTENT_LOCKED |
1460                                              EXTENT_DELALLOC, PAGE_UNLOCK |
1461                                              PAGE_SET_PRIVATE2);
1462                 if (!nolock && nocow)
1463                         btrfs_end_write_no_snapshoting(root);
1464                 cur_offset = extent_end;
1465                 if (cur_offset > end)
1466                         break;
1467         }
1468         btrfs_release_path(path);
1469
1470         if (cur_offset <= end && cow_start == (u64)-1) {
1471                 cow_start = cur_offset;
1472                 cur_offset = end;
1473         }
1474
1475         if (cow_start != (u64)-1) {
1476                 ret = cow_file_range(inode, locked_page, cow_start, end,
1477                                      page_started, nr_written, 1);
1478                 if (ret)
1479                         goto error;
1480         }
1481
1482 error:
1483         err = btrfs_end_transaction(trans, root);
1484         if (!ret)
1485                 ret = err;
1486
1487         if (ret && cur_offset < end)
1488                 extent_clear_unlock_delalloc(inode, cur_offset, end,
1489                                              locked_page, EXTENT_LOCKED |
1490                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1491                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1492                                              PAGE_CLEAR_DIRTY |
1493                                              PAGE_SET_WRITEBACK |
1494                                              PAGE_END_WRITEBACK);
1495         btrfs_free_path(path);
1496         return ret;
1497 }
1498
1499 static inline int need_force_cow(struct inode *inode, u64 start, u64 end)
1500 {
1501
1502         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
1503             !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC))
1504                 return 0;
1505
1506         /*
1507          * @defrag_bytes is a hint value, no spinlock held here,
1508          * if is not zero, it means the file is defragging.
1509          * Force cow if given extent needs to be defragged.
1510          */
1511         if (BTRFS_I(inode)->defrag_bytes &&
1512             test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
1513                            EXTENT_DEFRAG, 0, NULL))
1514                 return 1;
1515
1516         return 0;
1517 }
1518
1519 /*
1520  * extent_io.c call back to do delayed allocation processing
1521  */
1522 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1523                               u64 start, u64 end, int *page_started,
1524                               unsigned long *nr_written)
1525 {
1526         int ret;
1527         int force_cow = need_force_cow(inode, start, end);
1528
1529         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW && !force_cow) {
1530                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1531                                          page_started, 1, nr_written);
1532         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC && !force_cow) {
1533                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1534                                          page_started, 0, nr_written);
1535         } else if (!inode_need_compress(inode)) {
1536                 ret = cow_file_range(inode, locked_page, start, end,
1537                                       page_started, nr_written, 1);
1538         } else {
1539                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1540                         &BTRFS_I(inode)->runtime_flags);
1541                 ret = cow_file_range_async(inode, locked_page, start, end,
1542                                            page_started, nr_written);
1543         }
1544         return ret;
1545 }
1546
1547 static void btrfs_split_extent_hook(struct inode *inode,
1548                                     struct extent_state *orig, u64 split)
1549 {
1550         u64 size;
1551
1552         /* not delalloc, ignore it */
1553         if (!(orig->state & EXTENT_DELALLOC))
1554                 return;
1555
1556         size = orig->end - orig->start + 1;
1557         if (size > BTRFS_MAX_EXTENT_SIZE) {
1558                 u64 num_extents;
1559                 u64 new_size;
1560
1561                 /*
1562                  * See the explanation in btrfs_merge_extent_hook, the same
1563                  * applies here, just in reverse.
1564                  */
1565                 new_size = orig->end - split + 1;
1566                 num_extents = div64_u64(new_size + BTRFS_MAX_EXTENT_SIZE - 1,
1567                                         BTRFS_MAX_EXTENT_SIZE);
1568                 new_size = split - orig->start;
1569                 num_extents += div64_u64(new_size + BTRFS_MAX_EXTENT_SIZE - 1,
1570                                         BTRFS_MAX_EXTENT_SIZE);
1571                 if (div64_u64(size + BTRFS_MAX_EXTENT_SIZE - 1,
1572                               BTRFS_MAX_EXTENT_SIZE) >= num_extents)
1573                         return;
1574         }
1575
1576         spin_lock(&BTRFS_I(inode)->lock);
1577         BTRFS_I(inode)->outstanding_extents++;
1578         spin_unlock(&BTRFS_I(inode)->lock);
1579 }
1580
1581 /*
1582  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1583  * extents so we can keep track of new extents that are just merged onto old
1584  * extents, such as when we are doing sequential writes, so we can properly
1585  * account for the metadata space we'll need.
1586  */
1587 static void btrfs_merge_extent_hook(struct inode *inode,
1588                                     struct extent_state *new,
1589                                     struct extent_state *other)
1590 {
1591         u64 new_size, old_size;
1592         u64 num_extents;
1593
1594         /* not delalloc, ignore it */
1595         if (!(other->state & EXTENT_DELALLOC))
1596                 return;
1597
1598         if (new->start > other->start)
1599                 new_size = new->end - other->start + 1;
1600         else
1601                 new_size = other->end - new->start + 1;
1602
1603         /* we're not bigger than the max, unreserve the space and go */
1604         if (new_size <= BTRFS_MAX_EXTENT_SIZE) {
1605                 spin_lock(&BTRFS_I(inode)->lock);
1606                 BTRFS_I(inode)->outstanding_extents--;
1607                 spin_unlock(&BTRFS_I(inode)->lock);
1608                 return;
1609         }
1610
1611         /*
1612          * We have to add up either side to figure out how many extents were
1613          * accounted for before we merged into one big extent.  If the number of
1614          * extents we accounted for is <= the amount we need for the new range
1615          * then we can return, otherwise drop.  Think of it like this
1616          *
1617          * [ 4k][MAX_SIZE]
1618          *
1619          * So we've grown the extent by a MAX_SIZE extent, this would mean we
1620          * need 2 outstanding extents, on one side we have 1 and the other side
1621          * we have 1 so they are == and we can return.  But in this case
1622          *
1623          * [MAX_SIZE+4k][MAX_SIZE+4k]
1624          *
1625          * Each range on their own accounts for 2 extents, but merged together
1626          * they are only 3 extents worth of accounting, so we need to drop in
1627          * this case.
1628          */
1629         old_size = other->end - other->start + 1;
1630         num_extents = div64_u64(old_size + BTRFS_MAX_EXTENT_SIZE - 1,
1631                                 BTRFS_MAX_EXTENT_SIZE);
1632         old_size = new->end - new->start + 1;
1633         num_extents += div64_u64(old_size + BTRFS_MAX_EXTENT_SIZE - 1,
1634                                  BTRFS_MAX_EXTENT_SIZE);
1635
1636         if (div64_u64(new_size + BTRFS_MAX_EXTENT_SIZE - 1,
1637                       BTRFS_MAX_EXTENT_SIZE) >= num_extents)
1638                 return;
1639
1640         spin_lock(&BTRFS_I(inode)->lock);
1641         BTRFS_I(inode)->outstanding_extents--;
1642         spin_unlock(&BTRFS_I(inode)->lock);
1643 }
1644
1645 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1646                                       struct inode *inode)
1647 {
1648         spin_lock(&root->delalloc_lock);
1649         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1650                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1651                               &root->delalloc_inodes);
1652                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1653                         &BTRFS_I(inode)->runtime_flags);
1654                 root->nr_delalloc_inodes++;
1655                 if (root->nr_delalloc_inodes == 1) {
1656                         spin_lock(&root->fs_info->delalloc_root_lock);
1657                         BUG_ON(!list_empty(&root->delalloc_root));
1658                         list_add_tail(&root->delalloc_root,
1659                                       &root->fs_info->delalloc_roots);
1660                         spin_unlock(&root->fs_info->delalloc_root_lock);
1661                 }
1662         }
1663         spin_unlock(&root->delalloc_lock);
1664 }
1665
1666 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1667                                      struct inode *inode)
1668 {
1669         spin_lock(&root->delalloc_lock);
1670         if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1671                 list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1672                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1673                           &BTRFS_I(inode)->runtime_flags);
1674                 root->nr_delalloc_inodes--;
1675                 if (!root->nr_delalloc_inodes) {
1676                         spin_lock(&root->fs_info->delalloc_root_lock);
1677                         BUG_ON(list_empty(&root->delalloc_root));
1678                         list_del_init(&root->delalloc_root);
1679                         spin_unlock(&root->fs_info->delalloc_root_lock);
1680                 }
1681         }
1682         spin_unlock(&root->delalloc_lock);
1683 }
1684
1685 /*
1686  * extent_io.c set_bit_hook, used to track delayed allocation
1687  * bytes in this file, and to maintain the list of inodes that
1688  * have pending delalloc work to be done.
1689  */
1690 static void btrfs_set_bit_hook(struct inode *inode,
1691                                struct extent_state *state, unsigned *bits)
1692 {
1693
1694         if ((*bits & EXTENT_DEFRAG) && !(*bits & EXTENT_DELALLOC))
1695                 WARN_ON(1);
1696         /*
1697          * set_bit and clear bit hooks normally require _irqsave/restore
1698          * but in this case, we are only testing for the DELALLOC
1699          * bit, which is only set or cleared with irqs on
1700          */
1701         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1702                 struct btrfs_root *root = BTRFS_I(inode)->root;
1703                 u64 len = state->end + 1 - state->start;
1704                 bool do_list = !btrfs_is_free_space_inode(inode);
1705
1706                 if (*bits & EXTENT_FIRST_DELALLOC) {
1707                         *bits &= ~EXTENT_FIRST_DELALLOC;
1708                 } else {
1709                         spin_lock(&BTRFS_I(inode)->lock);
1710                         BTRFS_I(inode)->outstanding_extents++;
1711                         spin_unlock(&BTRFS_I(inode)->lock);
1712                 }
1713
1714                 /* For sanity tests */
1715                 if (btrfs_test_is_dummy_root(root))
1716                         return;
1717
1718                 __percpu_counter_add(&root->fs_info->delalloc_bytes, len,
1719                                      root->fs_info->delalloc_batch);
1720                 spin_lock(&BTRFS_I(inode)->lock);
1721                 BTRFS_I(inode)->delalloc_bytes += len;
1722                 if (*bits & EXTENT_DEFRAG)
1723                         BTRFS_I(inode)->defrag_bytes += len;
1724                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1725                                          &BTRFS_I(inode)->runtime_flags))
1726                         btrfs_add_delalloc_inodes(root, inode);
1727                 spin_unlock(&BTRFS_I(inode)->lock);
1728         }
1729 }
1730
1731 /*
1732  * extent_io.c clear_bit_hook, see set_bit_hook for why
1733  */
1734 static void btrfs_clear_bit_hook(struct inode *inode,
1735                                  struct extent_state *state,
1736                                  unsigned *bits)
1737 {
1738         u64 len = state->end + 1 - state->start;
1739         u64 num_extents = div64_u64(len + BTRFS_MAX_EXTENT_SIZE -1,
1740                                     BTRFS_MAX_EXTENT_SIZE);
1741
1742         spin_lock(&BTRFS_I(inode)->lock);
1743         if ((state->state & EXTENT_DEFRAG) && (*bits & EXTENT_DEFRAG))
1744                 BTRFS_I(inode)->defrag_bytes -= len;
1745         spin_unlock(&BTRFS_I(inode)->lock);
1746
1747         /*
1748          * set_bit and clear bit hooks normally require _irqsave/restore
1749          * but in this case, we are only testing for the DELALLOC
1750          * bit, which is only set or cleared with irqs on
1751          */
1752         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1753                 struct btrfs_root *root = BTRFS_I(inode)->root;
1754                 bool do_list = !btrfs_is_free_space_inode(inode);
1755
1756                 if (*bits & EXTENT_FIRST_DELALLOC) {
1757                         *bits &= ~EXTENT_FIRST_DELALLOC;
1758                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1759                         spin_lock(&BTRFS_I(inode)->lock);
1760                         BTRFS_I(inode)->outstanding_extents -= num_extents;
1761                         spin_unlock(&BTRFS_I(inode)->lock);
1762                 }
1763
1764                 /*
1765                  * We don't reserve metadata space for space cache inodes so we
1766                  * don't need to call dellalloc_release_metadata if there is an
1767                  * error.
1768                  */
1769                 if (*bits & EXTENT_DO_ACCOUNTING &&
1770                     root != root->fs_info->tree_root)
1771                         btrfs_delalloc_release_metadata(inode, len);
1772
1773                 /* For sanity tests. */
1774                 if (btrfs_test_is_dummy_root(root))
1775                         return;
1776
1777                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1778                     && do_list && !(state->state & EXTENT_NORESERVE))
1779                         btrfs_free_reserved_data_space_noquota(inode,
1780                                         state->start, len);
1781
1782                 __percpu_counter_add(&root->fs_info->delalloc_bytes, -len,
1783                                      root->fs_info->delalloc_batch);
1784                 spin_lock(&BTRFS_I(inode)->lock);
1785                 BTRFS_I(inode)->delalloc_bytes -= len;
1786                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1787                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1788                              &BTRFS_I(inode)->runtime_flags))
1789                         btrfs_del_delalloc_inode(root, inode);
1790                 spin_unlock(&BTRFS_I(inode)->lock);
1791         }
1792 }
1793
1794 /*
1795  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1796  * we don't create bios that span stripes or chunks
1797  */
1798 int btrfs_merge_bio_hook(int rw, struct page *page, unsigned long offset,
1799                          size_t size, struct bio *bio,
1800                          unsigned long bio_flags)
1801 {
1802         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1803         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1804         u64 length = 0;
1805         u64 map_length;
1806         int ret;
1807
1808         if (bio_flags & EXTENT_BIO_COMPRESSED)
1809                 return 0;
1810
1811         length = bio->bi_iter.bi_size;
1812         map_length = length;
1813         ret = btrfs_map_block(root->fs_info, rw, logical,
1814                               &map_length, NULL, 0);
1815         /* Will always return 0 with map_multi == NULL */
1816         BUG_ON(ret < 0);
1817         if (map_length < length + size)
1818                 return 1;
1819         return 0;
1820 }
1821
1822 /*
1823  * in order to insert checksums into the metadata in large chunks,
1824  * we wait until bio submission time.   All the pages in the bio are
1825  * checksummed and sums are attached onto the ordered extent record.
1826  *
1827  * At IO completion time the cums attached on the ordered extent record
1828  * are inserted into the btree
1829  */
1830 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1831                                     struct bio *bio, int mirror_num,
1832                                     unsigned long bio_flags,
1833                                     u64 bio_offset)
1834 {
1835         struct btrfs_root *root = BTRFS_I(inode)->root;
1836         int ret = 0;
1837
1838         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1839         BUG_ON(ret); /* -ENOMEM */
1840         return 0;
1841 }
1842
1843 /*
1844  * in order to insert checksums into the metadata in large chunks,
1845  * we wait until bio submission time.   All the pages in the bio are
1846  * checksummed and sums are attached onto the ordered extent record.
1847  *
1848  * At IO completion time the cums attached on the ordered extent record
1849  * are inserted into the btree
1850  */
1851 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1852                           int mirror_num, unsigned long bio_flags,
1853                           u64 bio_offset)
1854 {
1855         struct btrfs_root *root = BTRFS_I(inode)->root;
1856         int ret;
1857
1858         ret = btrfs_map_bio(root, rw, bio, mirror_num, 1);
1859         if (ret) {
1860                 bio->bi_error = ret;
1861                 bio_endio(bio);
1862         }
1863         return ret;
1864 }
1865
1866 /*
1867  * extent_io.c submission hook. This does the right thing for csum calculation
1868  * on write, or reading the csums from the tree before a read
1869  */
1870 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1871                           int mirror_num, unsigned long bio_flags,
1872                           u64 bio_offset)
1873 {
1874         struct btrfs_root *root = BTRFS_I(inode)->root;
1875         enum btrfs_wq_endio_type metadata = BTRFS_WQ_ENDIO_DATA;
1876         int ret = 0;
1877         int skip_sum;
1878         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1879
1880         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1881
1882         if (btrfs_is_free_space_inode(inode))
1883                 metadata = BTRFS_WQ_ENDIO_FREE_SPACE;
1884
1885         if (!(rw & REQ_WRITE)) {
1886                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, metadata);
1887                 if (ret)
1888                         goto out;
1889
1890                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1891                         ret = btrfs_submit_compressed_read(inode, bio,
1892                                                            mirror_num,
1893                                                            bio_flags);
1894                         goto out;
1895                 } else if (!skip_sum) {
1896                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1897                         if (ret)
1898                                 goto out;
1899                 }
1900                 goto mapit;
1901         } else if (async && !skip_sum) {
1902                 /* csum items have already been cloned */
1903                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1904                         goto mapit;
1905                 /* we're doing a write, do the async checksumming */
1906                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1907                                    inode, rw, bio, mirror_num,
1908                                    bio_flags, bio_offset,
1909                                    __btrfs_submit_bio_start,
1910                                    __btrfs_submit_bio_done);
1911                 goto out;
1912         } else if (!skip_sum) {
1913                 ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1914                 if (ret)
1915                         goto out;
1916         }
1917
1918 mapit:
1919         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
1920
1921 out:
1922         if (ret < 0) {
1923                 bio->bi_error = ret;
1924                 bio_endio(bio);
1925         }
1926         return ret;
1927 }
1928
1929 /*
1930  * given a list of ordered sums record them in the inode.  This happens
1931  * at IO completion time based on sums calculated at bio submission time.
1932  */
1933 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1934                              struct inode *inode, u64 file_offset,
1935                              struct list_head *list)
1936 {
1937         struct btrfs_ordered_sum *sum;
1938
1939         list_for_each_entry(sum, list, list) {
1940                 trans->adding_csums = 1;
1941                 btrfs_csum_file_blocks(trans,
1942                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1943                 trans->adding_csums = 0;
1944         }
1945         return 0;
1946 }
1947
1948 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1949                               struct extent_state **cached_state)
1950 {
1951         WARN_ON((end & (PAGE_CACHE_SIZE - 1)) == 0);
1952         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1953                                    cached_state, GFP_NOFS);
1954 }
1955
1956 /* see btrfs_writepage_start_hook for details on why this is required */
1957 struct btrfs_writepage_fixup {
1958         struct page *page;
1959         struct btrfs_work work;
1960 };
1961
1962 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1963 {
1964         struct btrfs_writepage_fixup *fixup;
1965         struct btrfs_ordered_extent *ordered;
1966         struct extent_state *cached_state = NULL;
1967         struct page *page;
1968         struct inode *inode;
1969         u64 page_start;
1970         u64 page_end;
1971         int ret;
1972
1973         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1974         page = fixup->page;
1975 again:
1976         lock_page(page);
1977         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1978                 ClearPageChecked(page);
1979                 goto out_page;
1980         }
1981
1982         inode = page->mapping->host;
1983         page_start = page_offset(page);
1984         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1985
1986         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1987                          &cached_state);
1988
1989         /* already ordered? We're done */
1990         if (PagePrivate2(page))
1991                 goto out;
1992
1993         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1994         if (ordered) {
1995                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1996                                      page_end, &cached_state, GFP_NOFS);
1997                 unlock_page(page);
1998                 btrfs_start_ordered_extent(inode, ordered, 1);
1999                 btrfs_put_ordered_extent(ordered);
2000                 goto again;
2001         }
2002
2003         ret = btrfs_delalloc_reserve_space(inode, page_start,
2004                                            PAGE_CACHE_SIZE);
2005         if (ret) {
2006                 mapping_set_error(page->mapping, ret);
2007                 end_extent_writepage(page, ret, page_start, page_end);
2008                 ClearPageChecked(page);
2009                 goto out;
2010          }
2011
2012         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
2013         ClearPageChecked(page);
2014         set_page_dirty(page);
2015 out:
2016         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
2017                              &cached_state, GFP_NOFS);
2018 out_page:
2019         unlock_page(page);
2020         page_cache_release(page);
2021         kfree(fixup);
2022 }
2023
2024 /*
2025  * There are a few paths in the higher layers of the kernel that directly
2026  * set the page dirty bit without asking the filesystem if it is a
2027  * good idea.  This causes problems because we want to make sure COW
2028  * properly happens and the data=ordered rules are followed.
2029  *
2030  * In our case any range that doesn't have the ORDERED bit set
2031  * hasn't been properly setup for IO.  We kick off an async process
2032  * to fix it up.  The async helper will wait for ordered extents, set
2033  * the delalloc bit and make it safe to write the page.
2034  */
2035 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
2036 {
2037         struct inode *inode = page->mapping->host;
2038         struct btrfs_writepage_fixup *fixup;
2039         struct btrfs_root *root = BTRFS_I(inode)->root;
2040
2041         /* this page is properly in the ordered list */
2042         if (TestClearPagePrivate2(page))
2043                 return 0;
2044
2045         if (PageChecked(page))
2046                 return -EAGAIN;
2047
2048         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
2049         if (!fixup)
2050                 return -EAGAIN;
2051
2052         SetPageChecked(page);
2053         page_cache_get(page);
2054         btrfs_init_work(&fixup->work, btrfs_fixup_helper,
2055                         btrfs_writepage_fixup_worker, NULL, NULL);
2056         fixup->page = page;
2057         btrfs_queue_work(root->fs_info->fixup_workers, &fixup->work);
2058         return -EBUSY;
2059 }
2060
2061 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
2062                                        struct inode *inode, u64 file_pos,
2063                                        u64 disk_bytenr, u64 disk_num_bytes,
2064                                        u64 num_bytes, u64 ram_bytes,
2065                                        u8 compression, u8 encryption,
2066                                        u16 other_encoding, int extent_type)
2067 {
2068         struct btrfs_root *root = BTRFS_I(inode)->root;
2069         struct btrfs_file_extent_item *fi;
2070         struct btrfs_path *path;
2071         struct extent_buffer *leaf;
2072         struct btrfs_key ins;
2073         int extent_inserted = 0;
2074         int ret;
2075
2076         path = btrfs_alloc_path();
2077         if (!path)
2078                 return -ENOMEM;
2079
2080         /*
2081          * we may be replacing one extent in the tree with another.
2082          * The new extent is pinned in the extent map, and we don't want
2083          * to drop it from the cache until it is completely in the btree.
2084          *
2085          * So, tell btrfs_drop_extents to leave this extent in the cache.
2086          * the caller is expected to unpin it and allow it to be merged
2087          * with the others.
2088          */
2089         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
2090                                    file_pos + num_bytes, NULL, 0,
2091                                    1, sizeof(*fi), &extent_inserted);
2092         if (ret)
2093                 goto out;
2094
2095         if (!extent_inserted) {
2096                 ins.objectid = btrfs_ino(inode);
2097                 ins.offset = file_pos;
2098                 ins.type = BTRFS_EXTENT_DATA_KEY;
2099
2100                 path->leave_spinning = 1;
2101                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
2102                                               sizeof(*fi));
2103                 if (ret)
2104                         goto out;
2105         }
2106         leaf = path->nodes[0];
2107         fi = btrfs_item_ptr(leaf, path->slots[0],
2108                             struct btrfs_file_extent_item);
2109         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2110         btrfs_set_file_extent_type(leaf, fi, extent_type);
2111         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
2112         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
2113         btrfs_set_file_extent_offset(leaf, fi, 0);
2114         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2115         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
2116         btrfs_set_file_extent_compression(leaf, fi, compression);
2117         btrfs_set_file_extent_encryption(leaf, fi, encryption);
2118         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
2119
2120         btrfs_mark_buffer_dirty(leaf);
2121         btrfs_release_path(path);
2122
2123         inode_add_bytes(inode, num_bytes);
2124
2125         ins.objectid = disk_bytenr;
2126         ins.offset = disk_num_bytes;
2127         ins.type = BTRFS_EXTENT_ITEM_KEY;
2128         ret = btrfs_alloc_reserved_file_extent(trans, root,
2129                                         root->root_key.objectid,
2130                                         btrfs_ino(inode), file_pos,
2131                                         ram_bytes, &ins);
2132         /*
2133          * Release the reserved range from inode dirty range map, as it is
2134          * already moved into delayed_ref_head
2135          */
2136         btrfs_qgroup_release_data(inode, file_pos, ram_bytes);
2137 out:
2138         btrfs_free_path(path);
2139
2140         return ret;
2141 }
2142
2143 /* snapshot-aware defrag */
2144 struct sa_defrag_extent_backref {
2145         struct rb_node node;
2146         struct old_sa_defrag_extent *old;
2147         u64 root_id;
2148         u64 inum;
2149         u64 file_pos;
2150         u64 extent_offset;
2151         u64 num_bytes;
2152         u64 generation;
2153 };
2154
2155 struct old_sa_defrag_extent {
2156         struct list_head list;
2157         struct new_sa_defrag_extent *new;
2158
2159         u64 extent_offset;
2160         u64 bytenr;
2161         u64 offset;
2162         u64 len;
2163         int count;
2164 };
2165
2166 struct new_sa_defrag_extent {
2167         struct rb_root root;
2168         struct list_head head;
2169         struct btrfs_path *path;
2170         struct inode *inode;
2171         u64 file_pos;
2172         u64 len;
2173         u64 bytenr;
2174         u64 disk_len;
2175         u8 compress_type;
2176 };
2177
2178 static int backref_comp(struct sa_defrag_extent_backref *b1,
2179                         struct sa_defrag_extent_backref *b2)
2180 {
2181         if (b1->root_id < b2->root_id)
2182                 return -1;
2183         else if (b1->root_id > b2->root_id)
2184                 return 1;
2185
2186         if (b1->inum < b2->inum)
2187                 return -1;
2188         else if (b1->inum > b2->inum)
2189                 return 1;
2190
2191         if (b1->file_pos < b2->file_pos)
2192                 return -1;
2193         else if (b1->file_pos > b2->file_pos)
2194                 return 1;
2195
2196         /*
2197          * [------------------------------] ===> (a range of space)
2198          *     |<--->|   |<---->| =============> (fs/file tree A)
2199          * |<---------------------------->| ===> (fs/file tree B)
2200          *
2201          * A range of space can refer to two file extents in one tree while
2202          * refer to only one file extent in another tree.
2203          *
2204          * So we may process a disk offset more than one time(two extents in A)
2205          * and locate at the same extent(one extent in B), then insert two same
2206          * backrefs(both refer to the extent in B).
2207          */
2208         return 0;
2209 }
2210
2211 static void backref_insert(struct rb_root *root,
2212                            struct sa_defrag_extent_backref *backref)
2213 {
2214         struct rb_node **p = &root->rb_node;
2215         struct rb_node *parent = NULL;
2216         struct sa_defrag_extent_backref *entry;
2217         int ret;
2218
2219         while (*p) {
2220                 parent = *p;
2221                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2222
2223                 ret = backref_comp(backref, entry);
2224                 if (ret < 0)
2225                         p = &(*p)->rb_left;
2226                 else
2227                         p = &(*p)->rb_right;
2228         }
2229
2230         rb_link_node(&backref->node, parent, p);
2231         rb_insert_color(&backref->node, root);
2232 }
2233
2234 /*
2235  * Note the backref might has changed, and in this case we just return 0.
2236  */
2237 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2238                                        void *ctx)
2239 {
2240         struct btrfs_file_extent_item *extent;
2241         struct btrfs_fs_info *fs_info;
2242         struct old_sa_defrag_extent *old = ctx;
2243         struct new_sa_defrag_extent *new = old->new;
2244         struct btrfs_path *path = new->path;
2245         struct btrfs_key key;
2246         struct btrfs_root *root;
2247         struct sa_defrag_extent_backref *backref;
2248         struct extent_buffer *leaf;
2249         struct inode *inode = new->inode;
2250         int slot;
2251         int ret;
2252         u64 extent_offset;
2253         u64 num_bytes;
2254
2255         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2256             inum == btrfs_ino(inode))
2257                 return 0;
2258
2259         key.objectid = root_id;
2260         key.type = BTRFS_ROOT_ITEM_KEY;
2261         key.offset = (u64)-1;
2262
2263         fs_info = BTRFS_I(inode)->root->fs_info;
2264         root = btrfs_read_fs_root_no_name(fs_info, &key);
2265         if (IS_ERR(root)) {
2266                 if (PTR_ERR(root) == -ENOENT)
2267                         return 0;
2268                 WARN_ON(1);
2269                 pr_debug("inum=%llu, offset=%llu, root_id=%llu\n",
2270                          inum, offset, root_id);
2271                 return PTR_ERR(root);
2272         }
2273
2274         key.objectid = inum;
2275         key.type = BTRFS_EXTENT_DATA_KEY;
2276         if (offset > (u64)-1 << 32)
2277                 key.offset = 0;
2278         else
2279                 key.offset = offset;
2280
2281         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2282         if (WARN_ON(ret < 0))
2283                 return ret;
2284         ret = 0;
2285
2286         while (1) {
2287                 cond_resched();
2288
2289                 leaf = path->nodes[0];
2290                 slot = path->slots[0];
2291
2292                 if (slot >= btrfs_header_nritems(leaf)) {
2293                         ret = btrfs_next_leaf(root, path);
2294                         if (ret < 0) {
2295                                 goto out;
2296                         } else if (ret > 0) {
2297                                 ret = 0;
2298                                 goto out;
2299                         }
2300                         continue;
2301                 }
2302
2303                 path->slots[0]++;
2304
2305                 btrfs_item_key_to_cpu(leaf, &key, slot);
2306
2307                 if (key.objectid > inum)
2308                         goto out;
2309
2310                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2311                         continue;
2312
2313                 extent = btrfs_item_ptr(leaf, slot,
2314                                         struct btrfs_file_extent_item);
2315
2316                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2317                         continue;
2318
2319                 /*
2320                  * 'offset' refers to the exact key.offset,
2321                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2322                  * (key.offset - extent_offset).
2323                  */
2324                 if (key.offset != offset)
2325                         continue;
2326
2327                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2328                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2329
2330                 if (extent_offset >= old->extent_offset + old->offset +
2331                     old->len || extent_offset + num_bytes <=
2332                     old->extent_offset + old->offset)
2333                         continue;
2334                 break;
2335         }
2336
2337         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2338         if (!backref) {
2339                 ret = -ENOENT;
2340                 goto out;
2341         }
2342
2343         backref->root_id = root_id;
2344         backref->inum = inum;
2345         backref->file_pos = offset;
2346         backref->num_bytes = num_bytes;
2347         backref->extent_offset = extent_offset;
2348         backref->generation = btrfs_file_extent_generation(leaf, extent);
2349         backref->old = old;
2350         backref_insert(&new->root, backref);
2351         old->count++;
2352 out:
2353         btrfs_release_path(path);
2354         WARN_ON(ret);
2355         return ret;
2356 }
2357
2358 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2359                                    struct new_sa_defrag_extent *new)
2360 {
2361         struct btrfs_fs_info *fs_info = BTRFS_I(new->inode)->root->fs_info;
2362         struct old_sa_defrag_extent *old, *tmp;
2363         int ret;
2364
2365         new->path = path;
2366
2367         list_for_each_entry_safe(old, tmp, &new->head, list) {
2368                 ret = iterate_inodes_from_logical(old->bytenr +
2369                                                   old->extent_offset, fs_info,
2370                                                   path, record_one_backref,
2371                                                   old);
2372                 if (ret < 0 && ret != -ENOENT)
2373                         return false;
2374
2375                 /* no backref to be processed for this extent */
2376                 if (!old->count) {
2377                         list_del(&old->list);
2378                         kfree(old);
2379                 }
2380         }
2381
2382         if (list_empty(&new->head))
2383                 return false;
2384
2385         return true;
2386 }
2387
2388 static int relink_is_mergable(struct extent_buffer *leaf,
2389                               struct btrfs_file_extent_item *fi,
2390                               struct new_sa_defrag_extent *new)
2391 {
2392         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2393                 return 0;
2394
2395         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2396                 return 0;
2397
2398         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2399                 return 0;
2400
2401         if (btrfs_file_extent_encryption(leaf, fi) ||
2402             btrfs_file_extent_other_encoding(leaf, fi))
2403                 return 0;
2404
2405         return 1;
2406 }
2407
2408 /*
2409  * Note the backref might has changed, and in this case we just return 0.
2410  */
2411 static noinline int relink_extent_backref(struct btrfs_path *path,
2412                                  struct sa_defrag_extent_backref *prev,
2413                                  struct sa_defrag_extent_backref *backref)
2414 {
2415         struct btrfs_file_extent_item *extent;
2416         struct btrfs_file_extent_item *item;
2417         struct btrfs_ordered_extent *ordered;
2418         struct btrfs_trans_handle *trans;
2419         struct btrfs_fs_info *fs_info;
2420         struct btrfs_root *root;
2421         struct btrfs_key key;
2422         struct extent_buffer *leaf;
2423         struct old_sa_defrag_extent *old = backref->old;
2424         struct new_sa_defrag_extent *new = old->new;
2425         struct inode *src_inode = new->inode;
2426         struct inode *inode;
2427         struct extent_state *cached = NULL;
2428         int ret = 0;
2429         u64 start;
2430         u64 len;
2431         u64 lock_start;
2432         u64 lock_end;
2433         bool merge = false;
2434         int index;
2435
2436         if (prev && prev->root_id == backref->root_id &&
2437             prev->inum == backref->inum &&
2438             prev->file_pos + prev->num_bytes == backref->file_pos)
2439                 merge = true;
2440
2441         /* step 1: get root */
2442         key.objectid = backref->root_id;
2443         key.type = BTRFS_ROOT_ITEM_KEY;
2444         key.offset = (u64)-1;
2445
2446         fs_info = BTRFS_I(src_inode)->root->fs_info;
2447         index = srcu_read_lock(&fs_info->subvol_srcu);
2448
2449         root = btrfs_read_fs_root_no_name(fs_info, &key);
2450         if (IS_ERR(root)) {
2451                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2452                 if (PTR_ERR(root) == -ENOENT)
2453                         return 0;
2454                 return PTR_ERR(root);
2455         }
2456
2457         if (btrfs_root_readonly(root)) {
2458                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2459                 return 0;
2460         }
2461
2462         /* step 2: get inode */
2463         key.objectid = backref->inum;
2464         key.type = BTRFS_INODE_ITEM_KEY;
2465         key.offset = 0;
2466
2467         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2468         if (IS_ERR(inode)) {
2469                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2470                 return 0;
2471         }
2472
2473         srcu_read_unlock(&fs_info->subvol_srcu, index);
2474
2475         /* step 3: relink backref */
2476         lock_start = backref->file_pos;
2477         lock_end = backref->file_pos + backref->num_bytes - 1;
2478         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2479                          0, &cached);
2480
2481         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2482         if (ordered) {
2483                 btrfs_put_ordered_extent(ordered);
2484                 goto out_unlock;
2485         }
2486
2487         trans = btrfs_join_transaction(root);
2488         if (IS_ERR(trans)) {
2489                 ret = PTR_ERR(trans);
2490                 goto out_unlock;
2491         }
2492
2493         key.objectid = backref->inum;
2494         key.type = BTRFS_EXTENT_DATA_KEY;
2495         key.offset = backref->file_pos;
2496
2497         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2498         if (ret < 0) {
2499                 goto out_free_path;
2500         } else if (ret > 0) {
2501                 ret = 0;
2502                 goto out_free_path;
2503         }
2504
2505         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2506                                 struct btrfs_file_extent_item);
2507
2508         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2509             backref->generation)
2510                 goto out_free_path;
2511
2512         btrfs_release_path(path);
2513
2514         start = backref->file_pos;
2515         if (backref->extent_offset < old->extent_offset + old->offset)
2516                 start += old->extent_offset + old->offset -
2517                          backref->extent_offset;
2518
2519         len = min(backref->extent_offset + backref->num_bytes,
2520                   old->extent_offset + old->offset + old->len);
2521         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2522
2523         ret = btrfs_drop_extents(trans, root, inode, start,
2524                                  start + len, 1);
2525         if (ret)
2526                 goto out_free_path;
2527 again:
2528         key.objectid = btrfs_ino(inode);
2529         key.type = BTRFS_EXTENT_DATA_KEY;
2530         key.offset = start;
2531
2532         path->leave_spinning = 1;
2533         if (merge) {
2534                 struct btrfs_file_extent_item *fi;
2535                 u64 extent_len;
2536                 struct btrfs_key found_key;
2537
2538                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2539                 if (ret < 0)
2540                         goto out_free_path;
2541
2542                 path->slots[0]--;
2543                 leaf = path->nodes[0];
2544                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2545
2546                 fi = btrfs_item_ptr(leaf, path->slots[0],
2547                                     struct btrfs_file_extent_item);
2548                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2549
2550                 if (extent_len + found_key.offset == start &&
2551                     relink_is_mergable(leaf, fi, new)) {
2552                         btrfs_set_file_extent_num_bytes(leaf, fi,
2553                                                         extent_len + len);
2554                         btrfs_mark_buffer_dirty(leaf);
2555                         inode_add_bytes(inode, len);
2556
2557                         ret = 1;
2558                         goto out_free_path;
2559                 } else {
2560                         merge = false;
2561                         btrfs_release_path(path);
2562                         goto again;
2563                 }
2564         }
2565
2566         ret = btrfs_insert_empty_item(trans, root, path, &key,
2567                                         sizeof(*extent));
2568         if (ret) {
2569                 btrfs_abort_transaction(trans, root, ret);
2570                 goto out_free_path;
2571         }
2572
2573         leaf = path->nodes[0];
2574         item = btrfs_item_ptr(leaf, path->slots[0],
2575                                 struct btrfs_file_extent_item);
2576         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2577         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2578         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2579         btrfs_set_file_extent_num_bytes(leaf, item, len);
2580         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2581         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2582         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2583         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2584         btrfs_set_file_extent_encryption(leaf, item, 0);
2585         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2586
2587         btrfs_mark_buffer_dirty(leaf);
2588         inode_add_bytes(inode, len);
2589         btrfs_release_path(path);
2590
2591         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2592                         new->disk_len, 0,
2593                         backref->root_id, backref->inum,
2594                         new->file_pos); /* start - extent_offset */
2595         if (ret) {
2596                 btrfs_abort_transaction(trans, root, ret);
2597                 goto out_free_path;
2598         }
2599
2600         ret = 1;
2601 out_free_path:
2602         btrfs_release_path(path);
2603         path->leave_spinning = 0;
2604         btrfs_end_transaction(trans, root);
2605 out_unlock:
2606         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2607                              &cached, GFP_NOFS);
2608         iput(inode);
2609         return ret;
2610 }
2611
2612 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2613 {
2614         struct old_sa_defrag_extent *old, *tmp;
2615
2616         if (!new)
2617                 return;
2618
2619         list_for_each_entry_safe(old, tmp, &new->head, list) {
2620                 kfree(old);
2621         }
2622         kfree(new);
2623 }
2624
2625 static void relink_file_extents(struct new_sa_defrag_extent *new)
2626 {
2627         struct btrfs_path *path;
2628         struct sa_defrag_extent_backref *backref;
2629         struct sa_defrag_extent_backref *prev = NULL;
2630         struct inode *inode;
2631         struct btrfs_root *root;
2632         struct rb_node *node;
2633         int ret;
2634
2635         inode = new->inode;
2636         root = BTRFS_I(inode)->root;
2637
2638         path = btrfs_alloc_path();
2639         if (!path)
2640                 return;
2641
2642         if (!record_extent_backrefs(path, new)) {
2643                 btrfs_free_path(path);
2644                 goto out;
2645         }
2646         btrfs_release_path(path);
2647
2648         while (1) {
2649                 node = rb_first(&new->root);
2650                 if (!node)
2651                         break;
2652                 rb_erase(node, &new->root);
2653
2654                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2655
2656                 ret = relink_extent_backref(path, prev, backref);
2657                 WARN_ON(ret < 0);
2658
2659                 kfree(prev);
2660
2661                 if (ret == 1)
2662                         prev = backref;
2663                 else
2664                         prev = NULL;
2665                 cond_resched();
2666         }
2667         kfree(prev);
2668
2669         btrfs_free_path(path);
2670 out:
2671         free_sa_defrag_extent(new);
2672
2673         atomic_dec(&root->fs_info->defrag_running);
2674         wake_up(&root->fs_info->transaction_wait);
2675 }
2676
2677 static struct new_sa_defrag_extent *
2678 record_old_file_extents(struct inode *inode,
2679                         struct btrfs_ordered_extent *ordered)
2680 {
2681         struct btrfs_root *root = BTRFS_I(inode)->root;
2682         struct btrfs_path *path;
2683         struct btrfs_key key;
2684         struct old_sa_defrag_extent *old;
2685         struct new_sa_defrag_extent *new;
2686         int ret;
2687
2688         new = kmalloc(sizeof(*new), GFP_NOFS);
2689         if (!new)
2690                 return NULL;
2691
2692         new->inode = inode;
2693         new->file_pos = ordered->file_offset;
2694         new->len = ordered->len;
2695         new->bytenr = ordered->start;
2696         new->disk_len = ordered->disk_len;
2697         new->compress_type = ordered->compress_type;
2698         new->root = RB_ROOT;
2699         INIT_LIST_HEAD(&new->head);
2700
2701         path = btrfs_alloc_path();
2702         if (!path)
2703                 goto out_kfree;
2704
2705         key.objectid = btrfs_ino(inode);
2706         key.type = BTRFS_EXTENT_DATA_KEY;
2707         key.offset = new->file_pos;
2708
2709         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2710         if (ret < 0)
2711                 goto out_free_path;
2712         if (ret > 0 && path->slots[0] > 0)
2713                 path->slots[0]--;
2714
2715         /* find out all the old extents for the file range */
2716         while (1) {
2717                 struct btrfs_file_extent_item *extent;
2718                 struct extent_buffer *l;
2719                 int slot;
2720                 u64 num_bytes;
2721                 u64 offset;
2722                 u64 end;
2723                 u64 disk_bytenr;
2724                 u64 extent_offset;
2725
2726                 l = path->nodes[0];
2727                 slot = path->slots[0];
2728
2729                 if (slot >= btrfs_header_nritems(l)) {
2730                         ret = btrfs_next_leaf(root, path);
2731                         if (ret < 0)
2732                                 goto out_free_path;
2733                         else if (ret > 0)
2734                                 break;
2735                         continue;
2736                 }
2737
2738                 btrfs_item_key_to_cpu(l, &key, slot);
2739
2740                 if (key.objectid != btrfs_ino(inode))
2741                         break;
2742                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2743                         break;
2744                 if (key.offset >= new->file_pos + new->len)
2745                         break;
2746
2747                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2748
2749                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2750                 if (key.offset + num_bytes < new->file_pos)
2751                         goto next;
2752
2753                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2754                 if (!disk_bytenr)
2755                         goto next;
2756
2757                 extent_offset = btrfs_file_extent_offset(l, extent);
2758
2759                 old = kmalloc(sizeof(*old), GFP_NOFS);
2760                 if (!old)
2761                         goto out_free_path;
2762
2763                 offset = max(new->file_pos, key.offset);
2764                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2765
2766                 old->bytenr = disk_bytenr;
2767                 old->extent_offset = extent_offset;
2768                 old->offset = offset - key.offset;
2769                 old->len = end - offset;
2770                 old->new = new;
2771                 old->count = 0;
2772                 list_add_tail(&old->list, &new->head);
2773 next:
2774                 path->slots[0]++;
2775                 cond_resched();
2776         }
2777
2778         btrfs_free_path(path);
2779         atomic_inc(&root->fs_info->defrag_running);
2780
2781         return new;
2782
2783 out_free_path:
2784         btrfs_free_path(path);
2785 out_kfree:
2786         free_sa_defrag_extent(new);
2787         return NULL;
2788 }
2789
2790 static void btrfs_release_delalloc_bytes(struct btrfs_root *root,
2791                                          u64 start, u64 len)
2792 {
2793         struct btrfs_block_group_cache *cache;
2794
2795         cache = btrfs_lookup_block_group(root->fs_info, start);
2796         ASSERT(cache);
2797
2798         spin_lock(&cache->lock);
2799         cache->delalloc_bytes -= len;
2800         spin_unlock(&cache->lock);
2801
2802         btrfs_put_block_group(cache);
2803 }
2804
2805 /* as ordered data IO finishes, this gets called so we can finish
2806  * an ordered extent if the range of bytes in the file it covers are
2807  * fully written.
2808  */
2809 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2810 {
2811         struct inode *inode = ordered_extent->inode;
2812         struct btrfs_root *root = BTRFS_I(inode)->root;
2813         struct btrfs_trans_handle *trans = NULL;
2814         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2815         struct extent_state *cached_state = NULL;
2816         struct new_sa_defrag_extent *new = NULL;
2817         int compress_type = 0;
2818         int ret = 0;
2819         u64 logical_len = ordered_extent->len;
2820         bool nolock;
2821         bool truncated = false;
2822
2823         nolock = btrfs_is_free_space_inode(inode);
2824
2825         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2826                 ret = -EIO;
2827                 goto out;
2828         }
2829
2830         btrfs_free_io_failure_record(inode, ordered_extent->file_offset,
2831                                      ordered_extent->file_offset +
2832                                      ordered_extent->len - 1);
2833
2834         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2835                 truncated = true;
2836                 logical_len = ordered_extent->truncated_len;
2837                 /* Truncated the entire extent, don't bother adding */
2838                 if (!logical_len)
2839                         goto out;
2840         }
2841
2842         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2843                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2844
2845                 /*
2846                  * For mwrite(mmap + memset to write) case, we still reserve
2847                  * space for NOCOW range.
2848                  * As NOCOW won't cause a new delayed ref, just free the space
2849                  */
2850                 btrfs_qgroup_free_data(inode, ordered_extent->file_offset,
2851                                        ordered_extent->len);
2852                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2853                 if (nolock)
2854                         trans = btrfs_join_transaction_nolock(root);
2855                 else
2856                         trans = btrfs_join_transaction(root);
2857                 if (IS_ERR(trans)) {
2858                         ret = PTR_ERR(trans);
2859                         trans = NULL;
2860                         goto out;
2861                 }
2862                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2863                 ret = btrfs_update_inode_fallback(trans, root, inode);
2864                 if (ret) /* -ENOMEM or corruption */
2865                         btrfs_abort_transaction(trans, root, ret);
2866                 goto out;
2867         }
2868
2869         lock_extent_bits(io_tree, ordered_extent->file_offset,
2870                          ordered_extent->file_offset + ordered_extent->len - 1,
2871                          0, &cached_state);
2872
2873         ret = test_range_bit(io_tree, ordered_extent->file_offset,
2874                         ordered_extent->file_offset + ordered_extent->len - 1,
2875                         EXTENT_DEFRAG, 1, cached_state);
2876         if (ret) {
2877                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2878                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
2879                         /* the inode is shared */
2880                         new = record_old_file_extents(inode, ordered_extent);
2881
2882                 clear_extent_bit(io_tree, ordered_extent->file_offset,
2883                         ordered_extent->file_offset + ordered_extent->len - 1,
2884                         EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS);
2885         }
2886
2887         if (nolock)
2888                 trans = btrfs_join_transaction_nolock(root);
2889         else
2890                 trans = btrfs_join_transaction(root);
2891         if (IS_ERR(trans)) {
2892                 ret = PTR_ERR(trans);
2893                 trans = NULL;
2894                 goto out_unlock;
2895         }
2896
2897         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2898
2899         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2900                 compress_type = ordered_extent->compress_type;
2901         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2902                 BUG_ON(compress_type);
2903                 ret = btrfs_mark_extent_written(trans, inode,
2904                                                 ordered_extent->file_offset,
2905                                                 ordered_extent->file_offset +
2906                                                 logical_len);
2907         } else {
2908                 BUG_ON(root == root->fs_info->tree_root);
2909                 ret = insert_reserved_file_extent(trans, inode,
2910                                                 ordered_extent->file_offset,
2911                                                 ordered_extent->start,
2912                                                 ordered_extent->disk_len,
2913                                                 logical_len, logical_len,
2914                                                 compress_type, 0, 0,
2915                                                 BTRFS_FILE_EXTENT_REG);
2916                 if (!ret)
2917                         btrfs_release_delalloc_bytes(root,
2918                                                      ordered_extent->start,
2919                                                      ordered_extent->disk_len);
2920         }
2921         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2922                            ordered_extent->file_offset, ordered_extent->len,
2923                            trans->transid);
2924         if (ret < 0) {
2925                 btrfs_abort_transaction(trans, root, ret);
2926                 goto out_unlock;
2927         }
2928
2929         add_pending_csums(trans, inode, ordered_extent->file_offset,
2930                           &ordered_extent->list);
2931
2932         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2933         ret = btrfs_update_inode_fallback(trans, root, inode);
2934         if (ret) { /* -ENOMEM or corruption */
2935                 btrfs_abort_transaction(trans, root, ret);
2936                 goto out_unlock;
2937         }
2938         ret = 0;
2939 out_unlock:
2940         unlock_extent_cached(io_tree, ordered_extent->file_offset,
2941                              ordered_extent->file_offset +
2942                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
2943 out:
2944         if (root != root->fs_info->tree_root)
2945                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
2946         if (trans)
2947                 btrfs_end_transaction(trans, root);
2948
2949         if (ret || truncated) {
2950                 u64 start, end;
2951
2952                 if (truncated)
2953                         start = ordered_extent->file_offset + logical_len;
2954                 else
2955                         start = ordered_extent->file_offset;
2956                 end = ordered_extent->file_offset + ordered_extent->len - 1;
2957                 clear_extent_uptodate(io_tree, start, end, NULL, GFP_NOFS);
2958
2959                 /* Drop the cache for the part of the extent we didn't write. */
2960                 btrfs_drop_extent_cache(inode, start, end, 0);
2961
2962                 /*
2963                  * If the ordered extent had an IOERR or something else went
2964                  * wrong we need to return the space for this ordered extent
2965                  * back to the allocator.  We only free the extent in the
2966                  * truncated case if we didn't write out the extent at all.
2967                  */
2968                 if ((ret || !logical_len) &&
2969                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2970                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
2971                         btrfs_free_reserved_extent(root, ordered_extent->start,
2972                                                    ordered_extent->disk_len, 1);
2973         }
2974
2975
2976         /*
2977          * This needs to be done to make sure anybody waiting knows we are done
2978          * updating everything for this ordered extent.
2979          */
2980         btrfs_remove_ordered_extent(inode, ordered_extent);
2981
2982         /* for snapshot-aware defrag */
2983         if (new) {
2984                 if (ret) {
2985                         free_sa_defrag_extent(new);
2986                         atomic_dec(&root->fs_info->defrag_running);
2987                 } else {
2988                         relink_file_extents(new);
2989                 }
2990         }
2991
2992         /* once for us */
2993         btrfs_put_ordered_extent(ordered_extent);
2994         /* once for the tree */
2995         btrfs_put_ordered_extent(ordered_extent);
2996
2997         return ret;
2998 }
2999
3000 static void finish_ordered_fn(struct btrfs_work *work)
3001 {
3002         struct btrfs_ordered_extent *ordered_extent;
3003         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
3004         btrfs_finish_ordered_io(ordered_extent);
3005 }
3006
3007 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
3008                                 struct extent_state *state, int uptodate)
3009 {
3010         struct inode *inode = page->mapping->host;
3011         struct btrfs_root *root = BTRFS_I(inode)->root;
3012         struct btrfs_ordered_extent *ordered_extent = NULL;
3013         struct btrfs_workqueue *wq;
3014         btrfs_work_func_t func;
3015
3016         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
3017
3018         ClearPagePrivate2(page);
3019         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
3020                                             end - start + 1, uptodate))
3021                 return 0;
3022
3023         if (btrfs_is_free_space_inode(inode)) {
3024                 wq = root->fs_info->endio_freespace_worker;
3025                 func = btrfs_freespace_write_helper;
3026         } else {
3027                 wq = root->fs_info->endio_write_workers;
3028                 func = btrfs_endio_write_helper;
3029         }
3030
3031         btrfs_init_work(&ordered_extent->work, func, finish_ordered_fn, NULL,
3032                         NULL);
3033         btrfs_queue_work(wq, &ordered_extent->work);
3034
3035         return 0;
3036 }
3037
3038 static int __readpage_endio_check(struct inode *inode,
3039                                   struct btrfs_io_bio *io_bio,
3040                                   int icsum, struct page *page,
3041                                   int pgoff, u64 start, size_t len)
3042 {
3043         char *kaddr;
3044         u32 csum_expected;
3045         u32 csum = ~(u32)0;
3046
3047         csum_expected = *(((u32 *)io_bio->csum) + icsum);
3048
3049         kaddr = kmap_atomic(page);
3050         csum = btrfs_csum_data(kaddr + pgoff, csum,  len);
3051         btrfs_csum_final(csum, (char *)&csum);
3052         if (csum != csum_expected)
3053                 goto zeroit;
3054
3055         kunmap_atomic(kaddr);
3056         return 0;
3057 zeroit:
3058         btrfs_warn_rl(BTRFS_I(inode)->root->fs_info,
3059                 "csum failed ino %llu off %llu csum %u expected csum %u",
3060                            btrfs_ino(inode), start, csum, csum_expected);
3061         memset(kaddr + pgoff, 1, len);
3062         flush_dcache_page(page);
3063         kunmap_atomic(kaddr);
3064         if (csum_expected == 0)
3065                 return 0;
3066         return -EIO;
3067 }
3068
3069 /*
3070  * when reads are done, we need to check csums to verify the data is correct
3071  * if there's a match, we allow the bio to finish.  If not, the code in
3072  * extent_io.c will try to find good copies for us.
3073  */
3074 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
3075                                       u64 phy_offset, struct page *page,
3076                                       u64 start, u64 end, int mirror)
3077 {
3078         size_t offset = start - page_offset(page);
3079         struct inode *inode = page->mapping->host;
3080         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3081         struct btrfs_root *root = BTRFS_I(inode)->root;
3082
3083         if (PageChecked(page)) {
3084                 ClearPageChecked(page);
3085                 return 0;
3086         }
3087
3088         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
3089                 return 0;
3090
3091         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
3092             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
3093                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
3094                                   GFP_NOFS);
3095                 return 0;
3096         }
3097
3098         phy_offset >>= inode->i_sb->s_blocksize_bits;
3099         return __readpage_endio_check(inode, io_bio, phy_offset, page, offset,
3100                                       start, (size_t)(end - start + 1));
3101 }
3102
3103 struct delayed_iput {
3104         struct list_head list;
3105         struct inode *inode;
3106 };
3107
3108 /* JDM: If this is fs-wide, why can't we add a pointer to
3109  * btrfs_inode instead and avoid the allocation? */
3110 void btrfs_add_delayed_iput(struct inode *inode)
3111 {
3112         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
3113         struct delayed_iput *delayed;
3114
3115         if (atomic_add_unless(&inode->i_count, -1, 1))
3116                 return;
3117
3118         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
3119         delayed->inode = inode;
3120
3121         spin_lock(&fs_info->delayed_iput_lock);
3122         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
3123         spin_unlock(&fs_info->delayed_iput_lock);
3124 }
3125
3126 void btrfs_run_delayed_iputs(struct btrfs_root *root)
3127 {
3128         LIST_HEAD(list);
3129         struct btrfs_fs_info *fs_info = root->fs_info;
3130         struct delayed_iput *delayed;
3131         int empty;
3132
3133         spin_lock(&fs_info->delayed_iput_lock);
3134         empty = list_empty(&fs_info->delayed_iputs);
3135         spin_unlock(&fs_info->delayed_iput_lock);
3136         if (empty)
3137                 return;
3138
3139         down_read(&fs_info->delayed_iput_sem);
3140
3141         spin_lock(&fs_info->delayed_iput_lock);
3142         list_splice_init(&fs_info->delayed_iputs, &list);
3143         spin_unlock(&fs_info->delayed_iput_lock);
3144
3145         while (!list_empty(&list)) {
3146                 delayed = list_entry(list.next, struct delayed_iput, list);
3147                 list_del(&delayed->list);
3148                 iput(delayed->inode);
3149                 kfree(delayed);
3150         }
3151
3152         up_read(&root->fs_info->delayed_iput_sem);
3153 }
3154
3155 /*
3156  * This is called in transaction commit time. If there are no orphan
3157  * files in the subvolume, it removes orphan item and frees block_rsv
3158  * structure.
3159  */
3160 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
3161                               struct btrfs_root *root)
3162 {
3163         struct btrfs_block_rsv *block_rsv;
3164         int ret;
3165
3166         if (atomic_read(&root->orphan_inodes) ||
3167             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
3168                 return;
3169
3170         spin_lock(&root->orphan_lock);
3171         if (atomic_read(&root->orphan_inodes)) {
3172                 spin_unlock(&root->orphan_lock);
3173                 return;
3174         }
3175
3176         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
3177                 spin_unlock(&root->orphan_lock);
3178                 return;
3179         }
3180
3181         block_rsv = root->orphan_block_rsv;
3182         root->orphan_block_rsv = NULL;
3183         spin_unlock(&root->orphan_lock);
3184
3185         if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state) &&
3186             btrfs_root_refs(&root->root_item) > 0) {
3187                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
3188                                             root->root_key.objectid);
3189                 if (ret)
3190                         btrfs_abort_transaction(trans, root, ret);
3191                 else
3192                         clear_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
3193                                   &root->state);
3194         }
3195
3196         if (block_rsv) {
3197                 WARN_ON(block_rsv->size > 0);
3198                 btrfs_free_block_rsv(root, block_rsv);
3199         }
3200 }
3201
3202 /*
3203  * This creates an orphan entry for the given inode in case something goes
3204  * wrong in the middle of an unlink/truncate.
3205  *
3206  * NOTE: caller of this function should reserve 5 units of metadata for
3207  *       this function.
3208  */
3209 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
3210 {
3211         struct btrfs_root *root = BTRFS_I(inode)->root;
3212         struct btrfs_block_rsv *block_rsv = NULL;
3213         int reserve = 0;
3214         int insert = 0;
3215         int ret;
3216
3217         if (!root->orphan_block_rsv) {
3218                 block_rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
3219                 if (!block_rsv)
3220                         return -ENOMEM;
3221         }
3222
3223         spin_lock(&root->orphan_lock);
3224         if (!root->orphan_block_rsv) {
3225                 root->orphan_block_rsv = block_rsv;
3226         } else if (block_rsv) {
3227                 btrfs_free_block_rsv(root, block_rsv);
3228                 block_rsv = NULL;
3229         }
3230
3231         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3232                               &BTRFS_I(inode)->runtime_flags)) {
3233 #if 0
3234                 /*
3235                  * For proper ENOSPC handling, we should do orphan
3236                  * cleanup when mounting. But this introduces backward
3237                  * compatibility issue.
3238                  */
3239                 if (!xchg(&root->orphan_item_inserted, 1))
3240                         insert = 2;
3241                 else
3242                         insert = 1;
3243 #endif
3244                 insert = 1;
3245                 atomic_inc(&root->orphan_inodes);
3246         }
3247
3248         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3249                               &BTRFS_I(inode)->runtime_flags))
3250                 reserve = 1;
3251         spin_unlock(&root->orphan_lock);
3252
3253         /* grab metadata reservation from transaction handle */
3254         if (reserve) {
3255                 ret = btrfs_orphan_reserve_metadata(trans, inode);
3256                 BUG_ON(ret); /* -ENOSPC in reservation; Logic error? JDM */
3257         }
3258
3259         /* insert an orphan item to track this unlinked/truncated file */
3260         if (insert >= 1) {
3261                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
3262                 if (ret) {
3263                         atomic_dec(&root->orphan_inodes);
3264                         if (reserve) {
3265                                 clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3266                                           &BTRFS_I(inode)->runtime_flags);
3267                                 btrfs_orphan_release_metadata(inode);
3268                         }
3269                         if (ret != -EEXIST) {
3270                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3271                                           &BTRFS_I(inode)->runtime_flags);
3272                                 btrfs_abort_transaction(trans, root, ret);
3273                                 return ret;
3274                         }
3275                 }
3276                 ret = 0;
3277         }
3278
3279         /* insert an orphan item to track subvolume contains orphan files */
3280         if (insert >= 2) {
3281                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
3282                                                root->root_key.objectid);
3283                 if (ret && ret != -EEXIST) {
3284                         btrfs_abort_transaction(trans, root, ret);
3285                         return ret;
3286                 }
3287         }
3288         return 0;
3289 }
3290
3291 /*
3292  * We have done the truncate/delete so we can go ahead and remove the orphan
3293  * item for this particular inode.
3294  */
3295 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3296                             struct inode *inode)
3297 {
3298         struct btrfs_root *root = BTRFS_I(inode)->root;
3299         int delete_item = 0;
3300         int release_rsv = 0;
3301         int ret = 0;
3302
3303         spin_lock(&root->orphan_lock);
3304         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3305                                &BTRFS_I(inode)->runtime_flags))
3306                 delete_item = 1;
3307
3308         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3309                                &BTRFS_I(inode)->runtime_flags))
3310                 release_rsv = 1;
3311         spin_unlock(&root->orphan_lock);
3312
3313         if (delete_item) {
3314                 atomic_dec(&root->orphan_inodes);
3315                 if (trans)
3316                         ret = btrfs_del_orphan_item(trans, root,
3317                                                     btrfs_ino(inode));
3318         }
3319
3320         if (release_rsv)
3321                 btrfs_orphan_release_metadata(inode);
3322
3323         return ret;
3324 }
3325
3326 /*
3327  * this cleans up any orphans that may be left on the list from the last use
3328  * of this root.
3329  */
3330 int btrfs_orphan_cleanup(struct btrfs_root *root)
3331 {
3332         struct btrfs_path *path;
3333         struct extent_buffer *leaf;
3334         struct btrfs_key key, found_key;
3335         struct btrfs_trans_handle *trans;
3336         struct inode *inode;
3337         u64 last_objectid = 0;
3338         int ret = 0, nr_unlink = 0, nr_truncate = 0;
3339
3340         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3341                 return 0;
3342
3343         path = btrfs_alloc_path();
3344         if (!path) {
3345                 ret = -ENOMEM;
3346                 goto out;
3347         }
3348         path->reada = -1;
3349
3350         key.objectid = BTRFS_ORPHAN_OBJECTID;
3351         key.type = BTRFS_ORPHAN_ITEM_KEY;
3352         key.offset = (u64)-1;
3353
3354         while (1) {
3355                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3356                 if (ret < 0)
3357                         goto out;
3358
3359                 /*
3360                  * if ret == 0 means we found what we were searching for, which
3361                  * is weird, but possible, so only screw with path if we didn't
3362                  * find the key and see if we have stuff that matches
3363                  */
3364                 if (ret > 0) {
3365                         ret = 0;
3366                         if (path->slots[0] == 0)
3367                                 break;
3368                         path->slots[0]--;
3369                 }
3370
3371                 /* pull out the item */
3372                 leaf = path->nodes[0];
3373                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3374
3375                 /* make sure the item matches what we want */
3376                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3377                         break;
3378                 if (found_key.type != BTRFS_ORPHAN_ITEM_KEY)
3379                         break;
3380
3381                 /* release the path since we're done with it */
3382                 btrfs_release_path(path);
3383
3384                 /*
3385                  * this is where we are basically btrfs_lookup, without the
3386                  * crossing root thing.  we store the inode number in the
3387                  * offset of the orphan item.
3388                  */
3389
3390                 if (found_key.offset == last_objectid) {
3391                         btrfs_err(root->fs_info,
3392                                 "Error removing orphan entry, stopping orphan cleanup");
3393                         ret = -EINVAL;
3394                         goto out;
3395                 }
3396
3397                 last_objectid = found_key.offset;
3398
3399                 found_key.objectid = found_key.offset;
3400                 found_key.type = BTRFS_INODE_ITEM_KEY;
3401                 found_key.offset = 0;
3402                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
3403                 ret = PTR_ERR_OR_ZERO(inode);
3404                 if (ret && ret != -ESTALE)
3405                         goto out;
3406
3407                 if (ret == -ESTALE && root == root->fs_info->tree_root) {
3408                         struct btrfs_root *dead_root;
3409                         struct btrfs_fs_info *fs_info = root->fs_info;
3410                         int is_dead_root = 0;
3411
3412                         /*
3413                          * this is an orphan in the tree root. Currently these
3414                          * could come from 2 sources:
3415                          *  a) a snapshot deletion in progress
3416                          *  b) a free space cache inode
3417                          * We need to distinguish those two, as the snapshot
3418                          * orphan must not get deleted.
3419                          * find_dead_roots already ran before us, so if this
3420                          * is a snapshot deletion, we should find the root
3421                          * in the dead_roots list
3422                          */
3423                         spin_lock(&fs_info->trans_lock);
3424                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3425                                             root_list) {
3426                                 if (dead_root->root_key.objectid ==
3427                                     found_key.objectid) {
3428                                         is_dead_root = 1;
3429                                         break;
3430                                 }
3431                         }
3432                         spin_unlock(&fs_info->trans_lock);
3433                         if (is_dead_root) {
3434                                 /* prevent this orphan from being found again */
3435                                 key.offset = found_key.objectid - 1;
3436                                 continue;
3437                         }
3438                 }
3439                 /*
3440                  * Inode is already gone but the orphan item is still there,
3441                  * kill the orphan item.
3442                  */
3443                 if (ret == -ESTALE) {
3444                         trans = btrfs_start_transaction(root, 1);
3445                         if (IS_ERR(trans)) {
3446                                 ret = PTR_ERR(trans);
3447                                 goto out;
3448                         }
3449                         btrfs_debug(root->fs_info, "auto deleting %Lu",
3450                                 found_key.objectid);
3451                         ret = btrfs_del_orphan_item(trans, root,
3452                                                     found_key.objectid);
3453                         btrfs_end_transaction(trans, root);
3454                         if (ret)
3455                                 goto out;
3456                         continue;
3457                 }
3458
3459                 /*
3460                  * add this inode to the orphan list so btrfs_orphan_del does
3461                  * the proper thing when we hit it
3462                  */
3463                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3464                         &BTRFS_I(inode)->runtime_flags);
3465                 atomic_inc(&root->orphan_inodes);
3466
3467                 /* if we have links, this was a truncate, lets do that */
3468                 if (inode->i_nlink) {
3469                         if (WARN_ON(!S_ISREG(inode->i_mode))) {
3470                                 iput(inode);
3471                                 continue;
3472                         }
3473                         nr_truncate++;
3474
3475                         /* 1 for the orphan item deletion. */
3476                         trans = btrfs_start_transaction(root, 1);
3477                         if (IS_ERR(trans)) {
3478                                 iput(inode);
3479                                 ret = PTR_ERR(trans);
3480                                 goto out;
3481                         }
3482                         ret = btrfs_orphan_add(trans, inode);
3483                         btrfs_end_transaction(trans, root);
3484                         if (ret) {
3485                                 iput(inode);
3486                                 goto out;
3487                         }
3488
3489                         ret = btrfs_truncate(inode);
3490                         if (ret)
3491                                 btrfs_orphan_del(NULL, inode);
3492                 } else {
3493                         nr_unlink++;
3494                 }
3495
3496                 /* this will do delete_inode and everything for us */
3497                 iput(inode);
3498                 if (ret)
3499                         goto out;
3500         }
3501         /* release the path since we're done with it */
3502         btrfs_release_path(path);
3503
3504         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3505
3506         if (root->orphan_block_rsv)
3507                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
3508                                         (u64)-1);
3509
3510         if (root->orphan_block_rsv ||
3511             test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
3512                 trans = btrfs_join_transaction(root);
3513                 if (!IS_ERR(trans))
3514                         btrfs_end_transaction(trans, root);
3515         }
3516
3517         if (nr_unlink)
3518                 btrfs_debug(root->fs_info, "unlinked %d orphans", nr_unlink);
3519         if (nr_truncate)
3520                 btrfs_debug(root->fs_info, "truncated %d orphans", nr_truncate);
3521
3522 out:
3523         if (ret)
3524                 btrfs_err(root->fs_info,
3525                         "could not do orphan cleanup %d", ret);
3526         btrfs_free_path(path);
3527         return ret;
3528 }
3529
3530 /*
3531  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3532  * don't find any xattrs, we know there can't be any acls.
3533  *
3534  * slot is the slot the inode is in, objectid is the objectid of the inode
3535  */
3536 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3537                                           int slot, u64 objectid,
3538                                           int *first_xattr_slot)
3539 {
3540         u32 nritems = btrfs_header_nritems(leaf);
3541         struct btrfs_key found_key;
3542         static u64 xattr_access = 0;
3543         static u64 xattr_default = 0;
3544         int scanned = 0;
3545
3546         if (!xattr_access) {
3547                 xattr_access = btrfs_name_hash(POSIX_ACL_XATTR_ACCESS,
3548                                         strlen(POSIX_ACL_XATTR_ACCESS));
3549                 xattr_default = btrfs_name_hash(POSIX_ACL_XATTR_DEFAULT,
3550                                         strlen(POSIX_ACL_XATTR_DEFAULT));
3551         }
3552
3553         slot++;
3554         *first_xattr_slot = -1;
3555         while (slot < nritems) {
3556                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3557
3558                 /* we found a different objectid, there must not be acls */
3559                 if (found_key.objectid != objectid)
3560                         return 0;
3561
3562                 /* we found an xattr, assume we've got an acl */
3563                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3564                         if (*first_xattr_slot == -1)
3565                                 *first_xattr_slot = slot;
3566                         if (found_key.offset == xattr_access ||
3567                             found_key.offset == xattr_default)
3568                                 return 1;
3569                 }
3570
3571                 /*
3572                  * we found a key greater than an xattr key, there can't
3573                  * be any acls later on
3574                  */
3575                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3576                         return 0;
3577
3578                 slot++;
3579                 scanned++;
3580
3581                 /*
3582                  * it goes inode, inode backrefs, xattrs, extents,
3583                  * so if there are a ton of hard links to an inode there can
3584                  * be a lot of backrefs.  Don't waste time searching too hard,
3585                  * this is just an optimization
3586                  */
3587                 if (scanned >= 8)
3588                         break;
3589         }
3590         /* we hit the end of the leaf before we found an xattr or
3591          * something larger than an xattr.  We have to assume the inode
3592          * has acls
3593          */
3594         if (*first_xattr_slot == -1)
3595                 *first_xattr_slot = slot;
3596         return 1;
3597 }
3598
3599 /*
3600  * read an inode from the btree into the in-memory inode
3601  */
3602 static void btrfs_read_locked_inode(struct inode *inode)
3603 {
3604         struct btrfs_path *path;
3605         struct extent_buffer *leaf;
3606         struct btrfs_inode_item *inode_item;
3607         struct btrfs_root *root = BTRFS_I(inode)->root;
3608         struct btrfs_key location;
3609         unsigned long ptr;
3610         int maybe_acls;
3611         u32 rdev;
3612         int ret;
3613         bool filled = false;
3614         int first_xattr_slot;
3615
3616         ret = btrfs_fill_inode(inode, &rdev);
3617         if (!ret)
3618                 filled = true;
3619
3620         path = btrfs_alloc_path();
3621         if (!path)
3622                 goto make_bad;
3623
3624         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3625
3626         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3627         if (ret)
3628                 goto make_bad;
3629
3630         leaf = path->nodes[0];
3631
3632         if (filled)
3633                 goto cache_index;
3634
3635         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3636                                     struct btrfs_inode_item);
3637         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3638         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3639         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3640         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3641         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
3642
3643         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->atime);
3644         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->atime);
3645
3646         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->mtime);
3647         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->mtime);
3648
3649         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->ctime);
3650         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->ctime);
3651
3652         BTRFS_I(inode)->i_otime.tv_sec =
3653                 btrfs_timespec_sec(leaf, &inode_item->otime);
3654         BTRFS_I(inode)->i_otime.tv_nsec =
3655                 btrfs_timespec_nsec(leaf, &inode_item->otime);
3656
3657         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3658         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3659         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3660
3661         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
3662         inode->i_generation = BTRFS_I(inode)->generation;
3663         inode->i_rdev = 0;
3664         rdev = btrfs_inode_rdev(leaf, inode_item);
3665
3666         BTRFS_I(inode)->index_cnt = (u64)-1;
3667         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3668
3669 cache_index:
3670         /*
3671          * If we were modified in the current generation and evicted from memory
3672          * and then re-read we need to do a full sync since we don't have any
3673          * idea about which extents were modified before we were evicted from
3674          * cache.
3675          *
3676          * This is required for both inode re-read from disk and delayed inode
3677          * in delayed_nodes_tree.
3678          */
3679         if (BTRFS_I(inode)->last_trans == root->fs_info->generation)
3680                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3681                         &BTRFS_I(inode)->runtime_flags);
3682
3683         /*
3684          * We don't persist the id of the transaction where an unlink operation
3685          * against the inode was last made. So here we assume the inode might
3686          * have been evicted, and therefore the exact value of last_unlink_trans
3687          * lost, and set it to last_trans to avoid metadata inconsistencies
3688          * between the inode and its parent if the inode is fsync'ed and the log
3689          * replayed. For example, in the scenario:
3690          *
3691          * touch mydir/foo
3692          * ln mydir/foo mydir/bar
3693          * sync
3694          * unlink mydir/bar
3695          * echo 2 > /proc/sys/vm/drop_caches   # evicts inode
3696          * xfs_io -c fsync mydir/foo
3697          * <power failure>
3698          * mount fs, triggers fsync log replay
3699          *
3700          * We must make sure that when we fsync our inode foo we also log its
3701          * parent inode, otherwise after log replay the parent still has the
3702          * dentry with the "bar" name but our inode foo has a link count of 1
3703          * and doesn't have an inode ref with the name "bar" anymore.
3704          *
3705          * Setting last_unlink_trans to last_trans is a pessimistic approach,
3706          * but it guarantees correctness at the expense of ocassional full
3707          * transaction commits on fsync if our inode is a directory, or if our
3708          * inode is not a directory, logging its parent unnecessarily.
3709          */
3710         BTRFS_I(inode)->last_unlink_trans = BTRFS_I(inode)->last_trans;
3711
3712         path->slots[0]++;
3713         if (inode->i_nlink != 1 ||
3714             path->slots[0] >= btrfs_header_nritems(leaf))
3715                 goto cache_acl;
3716
3717         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3718         if (location.objectid != btrfs_ino(inode))
3719                 goto cache_acl;
3720
3721         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3722         if (location.type == BTRFS_INODE_REF_KEY) {
3723                 struct btrfs_inode_ref *ref;
3724
3725                 ref = (struct btrfs_inode_ref *)ptr;
3726                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3727         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3728                 struct btrfs_inode_extref *extref;
3729
3730                 extref = (struct btrfs_inode_extref *)ptr;
3731                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3732                                                                      extref);
3733         }
3734 cache_acl:
3735         /*
3736          * try to precache a NULL acl entry for files that don't have
3737          * any xattrs or acls
3738          */
3739         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3740                                            btrfs_ino(inode), &first_xattr_slot);
3741         if (first_xattr_slot != -1) {
3742                 path->slots[0] = first_xattr_slot;
3743                 ret = btrfs_load_inode_props(inode, path);
3744                 if (ret)
3745                         btrfs_err(root->fs_info,
3746                                   "error loading props for ino %llu (root %llu): %d",
3747                                   btrfs_ino(inode),
3748                                   root->root_key.objectid, ret);
3749         }
3750         btrfs_free_path(path);
3751
3752         if (!maybe_acls)
3753                 cache_no_acl(inode);
3754
3755         switch (inode->i_mode & S_IFMT) {
3756         case S_IFREG:
3757                 inode->i_mapping->a_ops = &btrfs_aops;
3758                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3759                 inode->i_fop = &btrfs_file_operations;
3760                 inode->i_op = &btrfs_file_inode_operations;
3761                 break;
3762         case S_IFDIR:
3763                 inode->i_fop = &btrfs_dir_file_operations;
3764                 if (root == root->fs_info->tree_root)
3765                         inode->i_op = &btrfs_dir_ro_inode_operations;
3766                 else
3767                         inode->i_op = &btrfs_dir_inode_operations;
3768                 break;
3769         case S_IFLNK:
3770                 inode->i_op = &btrfs_symlink_inode_operations;
3771                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3772                 break;
3773         default:
3774                 inode->i_op = &btrfs_special_inode_operations;
3775                 init_special_inode(inode, inode->i_mode, rdev);
3776                 break;
3777         }
3778
3779         btrfs_update_iflags(inode);
3780         return;
3781
3782 make_bad:
3783         btrfs_free_path(path);
3784         make_bad_inode(inode);
3785 }
3786
3787 /*
3788  * given a leaf and an inode, copy the inode fields into the leaf
3789  */
3790 static void fill_inode_item(struct btrfs_trans_handle *trans,
3791                             struct extent_buffer *leaf,
3792                             struct btrfs_inode_item *item,
3793                             struct inode *inode)
3794 {
3795         struct btrfs_map_token token;
3796
3797         btrfs_init_map_token(&token);
3798
3799         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3800         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3801         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3802                                    &token);
3803         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3804         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3805
3806         btrfs_set_token_timespec_sec(leaf, &item->atime,
3807                                      inode->i_atime.tv_sec, &token);
3808         btrfs_set_token_timespec_nsec(leaf, &item->atime,
3809                                       inode->i_atime.tv_nsec, &token);
3810
3811         btrfs_set_token_timespec_sec(leaf, &item->mtime,
3812                                      inode->i_mtime.tv_sec, &token);
3813         btrfs_set_token_timespec_nsec(leaf, &item->mtime,
3814                                       inode->i_mtime.tv_nsec, &token);
3815
3816         btrfs_set_token_timespec_sec(leaf, &item->ctime,
3817                                      inode->i_ctime.tv_sec, &token);
3818         btrfs_set_token_timespec_nsec(leaf, &item->ctime,
3819                                       inode->i_ctime.tv_nsec, &token);
3820
3821         btrfs_set_token_timespec_sec(leaf, &item->otime,
3822                                      BTRFS_I(inode)->i_otime.tv_sec, &token);
3823         btrfs_set_token_timespec_nsec(leaf, &item->otime,
3824                                       BTRFS_I(inode)->i_otime.tv_nsec, &token);
3825
3826         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3827                                      &token);
3828         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3829                                          &token);
3830         btrfs_set_token_inode_sequence(leaf, item, inode->i_version, &token);
3831         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3832         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3833         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3834         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3835 }
3836
3837 /*
3838  * copy everything in the in-memory inode into the btree.
3839  */
3840 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3841                                 struct btrfs_root *root, struct inode *inode)
3842 {
3843         struct btrfs_inode_item *inode_item;
3844         struct btrfs_path *path;
3845         struct extent_buffer *leaf;
3846         int ret;
3847
3848         path = btrfs_alloc_path();
3849         if (!path)
3850                 return -ENOMEM;
3851
3852         path->leave_spinning = 1;
3853         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3854                                  1);
3855         if (ret) {
3856                 if (ret > 0)
3857                         ret = -ENOENT;
3858                 goto failed;
3859         }
3860
3861         leaf = path->nodes[0];
3862         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3863                                     struct btrfs_inode_item);
3864
3865         fill_inode_item(trans, leaf, inode_item, inode);
3866         btrfs_mark_buffer_dirty(leaf);
3867         btrfs_set_inode_last_trans(trans, inode);
3868         ret = 0;
3869 failed:
3870         btrfs_free_path(path);
3871         return ret;
3872 }
3873
3874 /*
3875  * copy everything in the in-memory inode into the btree.
3876  */
3877 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3878                                 struct btrfs_root *root, struct inode *inode)
3879 {
3880         int ret;
3881
3882         /*
3883          * If the inode is a free space inode, we can deadlock during commit
3884          * if we put it into the delayed code.
3885          *
3886          * The data relocation inode should also be directly updated
3887          * without delay
3888          */
3889         if (!btrfs_is_free_space_inode(inode)
3890             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
3891             && !root->fs_info->log_root_recovering) {
3892                 btrfs_update_root_times(trans, root);
3893
3894                 ret = btrfs_delayed_update_inode(trans, root, inode);
3895                 if (!ret)
3896                         btrfs_set_inode_last_trans(trans, inode);
3897                 return ret;
3898         }
3899
3900         return btrfs_update_inode_item(trans, root, inode);
3901 }
3902
3903 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3904                                          struct btrfs_root *root,
3905                                          struct inode *inode)
3906 {
3907         int ret;
3908
3909         ret = btrfs_update_inode(trans, root, inode);
3910         if (ret == -ENOSPC)
3911                 return btrfs_update_inode_item(trans, root, inode);
3912         return ret;
3913 }
3914
3915 /*
3916  * unlink helper that gets used here in inode.c and in the tree logging
3917  * recovery code.  It remove a link in a directory with a given name, and
3918  * also drops the back refs in the inode to the directory
3919  */
3920 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3921                                 struct btrfs_root *root,
3922                                 struct inode *dir, struct inode *inode,
3923                                 const char *name, int name_len)
3924 {
3925         struct btrfs_path *path;
3926         int ret = 0;
3927         struct extent_buffer *leaf;
3928         struct btrfs_dir_item *di;
3929         struct btrfs_key key;
3930         u64 index;
3931         u64 ino = btrfs_ino(inode);
3932         u64 dir_ino = btrfs_ino(dir);
3933
3934         path = btrfs_alloc_path();
3935         if (!path) {
3936                 ret = -ENOMEM;
3937                 goto out;
3938         }
3939
3940         path->leave_spinning = 1;
3941         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3942                                     name, name_len, -1);
3943         if (IS_ERR(di)) {
3944                 ret = PTR_ERR(di);
3945                 goto err;
3946         }
3947         if (!di) {
3948                 ret = -ENOENT;
3949                 goto err;
3950         }
3951         leaf = path->nodes[0];
3952         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3953         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3954         if (ret)
3955                 goto err;
3956         btrfs_release_path(path);
3957
3958         /*
3959          * If we don't have dir index, we have to get it by looking up
3960          * the inode ref, since we get the inode ref, remove it directly,
3961          * it is unnecessary to do delayed deletion.
3962          *
3963          * But if we have dir index, needn't search inode ref to get it.
3964          * Since the inode ref is close to the inode item, it is better
3965          * that we delay to delete it, and just do this deletion when
3966          * we update the inode item.
3967          */
3968         if (BTRFS_I(inode)->dir_index) {
3969                 ret = btrfs_delayed_delete_inode_ref(inode);
3970                 if (!ret) {
3971                         index = BTRFS_I(inode)->dir_index;
3972                         goto skip_backref;
3973                 }
3974         }
3975
3976         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3977                                   dir_ino, &index);
3978         if (ret) {
3979                 btrfs_info(root->fs_info,
3980                         "failed to delete reference to %.*s, inode %llu parent %llu",
3981                         name_len, name, ino, dir_ino);
3982                 btrfs_abort_transaction(trans, root, ret);
3983                 goto err;
3984         }
3985 skip_backref:
3986         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3987         if (ret) {
3988                 btrfs_abort_transaction(trans, root, ret);
3989                 goto err;
3990         }
3991
3992         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
3993                                          inode, dir_ino);
3994         if (ret != 0 && ret != -ENOENT) {
3995                 btrfs_abort_transaction(trans, root, ret);
3996                 goto err;
3997         }
3998
3999         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
4000                                            dir, index);
4001         if (ret == -ENOENT)
4002                 ret = 0;
4003         else if (ret)
4004                 btrfs_abort_transaction(trans, root, ret);
4005 err:
4006         btrfs_free_path(path);
4007         if (ret)
4008                 goto out;
4009
4010         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
4011         inode_inc_iversion(inode);
4012         inode_inc_iversion(dir);
4013         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
4014         ret = btrfs_update_inode(trans, root, dir);
4015 out:
4016         return ret;
4017 }
4018
4019 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
4020                        struct btrfs_root *root,
4021                        struct inode *dir, struct inode *inode,
4022                        const char *name, int name_len)
4023 {
4024         int ret;
4025         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
4026         if (!ret) {
4027                 drop_nlink(inode);
4028                 ret = btrfs_update_inode(trans, root, inode);
4029         }
4030         return ret;
4031 }
4032
4033 /*
4034  * helper to start transaction for unlink and rmdir.
4035  *
4036  * unlink and rmdir are special in btrfs, they do not always free space, so
4037  * if we cannot make our reservations the normal way try and see if there is
4038  * plenty of slack room in the global reserve to migrate, otherwise we cannot
4039  * allow the unlink to occur.
4040  */
4041 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
4042 {
4043         struct btrfs_trans_handle *trans;
4044         struct btrfs_root *root = BTRFS_I(dir)->root;
4045         int ret;
4046
4047         /*
4048          * 1 for the possible orphan item
4049          * 1 for the dir item
4050          * 1 for the dir index
4051          * 1 for the inode ref
4052          * 1 for the inode
4053          */
4054         trans = btrfs_start_transaction(root, 5);
4055         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
4056                 return trans;
4057
4058         if (PTR_ERR(trans) == -ENOSPC) {
4059                 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
4060
4061                 trans = btrfs_start_transaction(root, 0);
4062                 if (IS_ERR(trans))
4063                         return trans;
4064                 ret = btrfs_cond_migrate_bytes(root->fs_info,
4065                                                &root->fs_info->trans_block_rsv,
4066                                                num_bytes, 5);
4067                 if (ret) {
4068                         btrfs_end_transaction(trans, root);
4069                         return ERR_PTR(ret);
4070                 }
4071                 trans->block_rsv = &root->fs_info->trans_block_rsv;
4072                 trans->bytes_reserved = num_bytes;
4073         }
4074         return trans;
4075 }
4076
4077 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
4078 {
4079         struct btrfs_root *root = BTRFS_I(dir)->root;
4080         struct btrfs_trans_handle *trans;
4081         struct inode *inode = d_inode(dentry);
4082         int ret;
4083
4084         trans = __unlink_start_trans(dir);
4085         if (IS_ERR(trans))
4086                 return PTR_ERR(trans);
4087
4088         btrfs_record_unlink_dir(trans, dir, d_inode(dentry), 0);
4089
4090         ret = btrfs_unlink_inode(trans, root, dir, d_inode(dentry),
4091                                  dentry->d_name.name, dentry->d_name.len);
4092         if (ret)
4093                 goto out;
4094
4095         if (inode->i_nlink == 0) {
4096                 ret = btrfs_orphan_add(trans, inode);
4097                 if (ret)
4098                         goto out;
4099         }
4100
4101 out:
4102         btrfs_end_transaction(trans, root);
4103         btrfs_btree_balance_dirty(root);
4104         return ret;
4105 }
4106
4107 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
4108                         struct btrfs_root *root,
4109                         struct inode *dir, u64 objectid,
4110                         const char *name, int name_len)
4111 {
4112         struct btrfs_path *path;
4113         struct extent_buffer *leaf;
4114         struct btrfs_dir_item *di;
4115         struct btrfs_key key;
4116         u64 index;
4117         int ret;
4118         u64 dir_ino = btrfs_ino(dir);
4119
4120         path = btrfs_alloc_path();
4121         if (!path)
4122                 return -ENOMEM;
4123
4124         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
4125                                    name, name_len, -1);
4126         if (IS_ERR_OR_NULL(di)) {
4127                 if (!di)
4128                         ret = -ENOENT;
4129                 else
4130                         ret = PTR_ERR(di);
4131                 goto out;
4132         }
4133
4134         leaf = path->nodes[0];
4135         btrfs_dir_item_key_to_cpu(leaf, di, &key);
4136         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
4137         ret = btrfs_delete_one_dir_name(trans, root, path, di);
4138         if (ret) {
4139                 btrfs_abort_transaction(trans, root, ret);
4140                 goto out;
4141         }
4142         btrfs_release_path(path);
4143
4144         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
4145                                  objectid, root->root_key.objectid,
4146                                  dir_ino, &index, name, name_len);
4147         if (ret < 0) {
4148                 if (ret != -ENOENT) {
4149                         btrfs_abort_transaction(trans, root, ret);
4150                         goto out;
4151                 }
4152                 di = btrfs_search_dir_index_item(root, path, dir_ino,
4153                                                  name, name_len);
4154                 if (IS_ERR_OR_NULL(di)) {
4155                         if (!di)
4156                                 ret = -ENOENT;
4157                         else
4158                                 ret = PTR_ERR(di);
4159                         btrfs_abort_transaction(trans, root, ret);
4160                         goto out;
4161                 }
4162
4163                 leaf = path->nodes[0];
4164                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4165                 btrfs_release_path(path);
4166                 index = key.offset;
4167         }
4168         btrfs_release_path(path);
4169
4170         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
4171         if (ret) {
4172                 btrfs_abort_transaction(trans, root, ret);
4173                 goto out;
4174         }
4175
4176         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
4177         inode_inc_iversion(dir);
4178         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
4179         ret = btrfs_update_inode_fallback(trans, root, dir);
4180         if (ret)
4181                 btrfs_abort_transaction(trans, root, ret);
4182 out:
4183         btrfs_free_path(path);
4184         return ret;
4185 }
4186
4187 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
4188 {
4189         struct inode *inode = d_inode(dentry);
4190         int err = 0;
4191         struct btrfs_root *root = BTRFS_I(dir)->root;
4192         struct btrfs_trans_handle *trans;
4193
4194         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
4195                 return -ENOTEMPTY;
4196         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
4197                 return -EPERM;
4198
4199         trans = __unlink_start_trans(dir);
4200         if (IS_ERR(trans))
4201                 return PTR_ERR(trans);
4202
4203         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
4204                 err = btrfs_unlink_subvol(trans, root, dir,
4205                                           BTRFS_I(inode)->location.objectid,
4206                                           dentry->d_name.name,
4207                                           dentry->d_name.len);
4208                 goto out;
4209         }
4210
4211         err = btrfs_orphan_add(trans, inode);
4212         if (err)
4213                 goto out;
4214
4215         /* now the directory is empty */
4216         err = btrfs_unlink_inode(trans, root, dir, d_inode(dentry),
4217                                  dentry->d_name.name, dentry->d_name.len);
4218         if (!err)
4219                 btrfs_i_size_write(inode, 0);
4220 out:
4221         btrfs_end_transaction(trans, root);
4222         btrfs_btree_balance_dirty(root);
4223
4224         return err;
4225 }
4226
4227 static int truncate_space_check(struct btrfs_trans_handle *trans,
4228                                 struct btrfs_root *root,
4229                                 u64 bytes_deleted)
4230 {
4231         int ret;
4232
4233         bytes_deleted = btrfs_csum_bytes_to_leaves(root, bytes_deleted);
4234         ret = btrfs_block_rsv_add(root, &root->fs_info->trans_block_rsv,
4235                                   bytes_deleted, BTRFS_RESERVE_NO_FLUSH);
4236         if (!ret)
4237                 trans->bytes_reserved += bytes_deleted;
4238         return ret;
4239
4240 }
4241
4242 static int truncate_inline_extent(struct inode *inode,
4243                                   struct btrfs_path *path,
4244                                   struct btrfs_key *found_key,
4245                                   const u64 item_end,
4246                                   const u64 new_size)
4247 {
4248         struct extent_buffer *leaf = path->nodes[0];
4249         int slot = path->slots[0];
4250         struct btrfs_file_extent_item *fi;
4251         u32 size = (u32)(new_size - found_key->offset);
4252         struct btrfs_root *root = BTRFS_I(inode)->root;
4253
4254         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
4255
4256         if (btrfs_file_extent_compression(leaf, fi) != BTRFS_COMPRESS_NONE) {
4257                 loff_t offset = new_size;
4258                 loff_t page_end = ALIGN(offset, PAGE_CACHE_SIZE);
4259
4260                 /*
4261                  * Zero out the remaining of the last page of our inline extent,
4262                  * instead of directly truncating our inline extent here - that
4263                  * would be much more complex (decompressing all the data, then
4264                  * compressing the truncated data, which might be bigger than
4265                  * the size of the inline extent, resize the extent, etc).
4266                  * We release the path because to get the page we might need to
4267                  * read the extent item from disk (data not in the page cache).
4268                  */
4269                 btrfs_release_path(path);
4270                 return btrfs_truncate_page(inode, offset, page_end - offset, 0);
4271         }
4272
4273         btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4274         size = btrfs_file_extent_calc_inline_size(size);
4275         btrfs_truncate_item(root, path, size, 1);
4276
4277         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4278                 inode_sub_bytes(inode, item_end + 1 - new_size);
4279
4280         return 0;
4281 }
4282
4283 /*
4284  * this can truncate away extent items, csum items and directory items.
4285  * It starts at a high offset and removes keys until it can't find
4286  * any higher than new_size
4287  *
4288  * csum items that cross the new i_size are truncated to the new size
4289  * as well.
4290  *
4291  * min_type is the minimum key type to truncate down to.  If set to 0, this
4292  * will kill all the items on this inode, including the INODE_ITEM_KEY.
4293  */
4294 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
4295                                struct btrfs_root *root,
4296                                struct inode *inode,
4297                                u64 new_size, u32 min_type)
4298 {
4299         struct btrfs_path *path;
4300         struct extent_buffer *leaf;
4301         struct btrfs_file_extent_item *fi;
4302         struct btrfs_key key;
4303         struct btrfs_key found_key;
4304         u64 extent_start = 0;
4305         u64 extent_num_bytes = 0;
4306         u64 extent_offset = 0;
4307         u64 item_end = 0;
4308         u64 last_size = new_size;
4309         u32 found_type = (u8)-1;
4310         int found_extent;
4311         int del_item;
4312         int pending_del_nr = 0;
4313         int pending_del_slot = 0;
4314         int extent_type = -1;
4315         int ret;
4316         int err = 0;
4317         u64 ino = btrfs_ino(inode);
4318         u64 bytes_deleted = 0;
4319         bool be_nice = 0;
4320         bool should_throttle = 0;
4321         bool should_end = 0;
4322
4323         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
4324
4325         /*
4326          * for non-free space inodes and ref cows, we want to back off from
4327          * time to time
4328          */
4329         if (!btrfs_is_free_space_inode(inode) &&
4330             test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4331                 be_nice = 1;
4332
4333         path = btrfs_alloc_path();
4334         if (!path)
4335                 return -ENOMEM;
4336         path->reada = -1;
4337
4338         /*
4339          * We want to drop from the next block forward in case this new size is
4340          * not block aligned since we will be keeping the last block of the
4341          * extent just the way it is.
4342          */
4343         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4344             root == root->fs_info->tree_root)
4345                 btrfs_drop_extent_cache(inode, ALIGN(new_size,
4346                                         root->sectorsize), (u64)-1, 0);
4347
4348         /*
4349          * This function is also used to drop the items in the log tree before
4350          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4351          * it is used to drop the loged items. So we shouldn't kill the delayed
4352          * items.
4353          */
4354         if (min_type == 0 && root == BTRFS_I(inode)->root)
4355                 btrfs_kill_delayed_inode_items(inode);
4356
4357         key.objectid = ino;
4358         key.offset = (u64)-1;
4359         key.type = (u8)-1;
4360
4361 search_again:
4362         /*
4363          * with a 16K leaf size and 128MB extents, you can actually queue
4364          * up a huge file in a single leaf.  Most of the time that
4365          * bytes_deleted is > 0, it will be huge by the time we get here
4366          */
4367         if (be_nice && bytes_deleted > 32 * 1024 * 1024) {
4368                 if (btrfs_should_end_transaction(trans, root)) {
4369                         err = -EAGAIN;
4370                         goto error;
4371                 }
4372         }
4373
4374
4375         path->leave_spinning = 1;
4376         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4377         if (ret < 0) {
4378                 err = ret;
4379                 goto out;
4380         }
4381
4382         if (ret > 0) {
4383                 /* there are no items in the tree for us to truncate, we're
4384                  * done
4385                  */
4386                 if (path->slots[0] == 0)
4387                         goto out;
4388                 path->slots[0]--;
4389         }
4390
4391         while (1) {
4392                 fi = NULL;
4393                 leaf = path->nodes[0];
4394                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4395                 found_type = found_key.type;
4396
4397                 if (found_key.objectid != ino)
4398                         break;
4399
4400                 if (found_type < min_type)
4401                         break;
4402
4403                 item_end = found_key.offset;
4404                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4405                         fi = btrfs_item_ptr(leaf, path->slots[0],
4406                                             struct btrfs_file_extent_item);
4407                         extent_type = btrfs_file_extent_type(leaf, fi);
4408                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4409                                 item_end +=
4410                                     btrfs_file_extent_num_bytes(leaf, fi);
4411                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4412                                 item_end += btrfs_file_extent_inline_len(leaf,
4413                                                          path->slots[0], fi);
4414                         }
4415                         item_end--;
4416                 }
4417                 if (found_type > min_type) {
4418                         del_item = 1;
4419                 } else {
4420                         if (item_end < new_size)
4421                                 break;
4422                         if (found_key.offset >= new_size)
4423                                 del_item = 1;
4424                         else
4425                                 del_item = 0;
4426                 }
4427                 found_extent = 0;
4428                 /* FIXME, shrink the extent if the ref count is only 1 */
4429                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4430                         goto delete;
4431
4432                 if (del_item)
4433                         last_size = found_key.offset;
4434                 else
4435                         last_size = new_size;
4436
4437                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4438                         u64 num_dec;
4439                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4440                         if (!del_item) {
4441                                 u64 orig_num_bytes =
4442                                         btrfs_file_extent_num_bytes(leaf, fi);
4443                                 extent_num_bytes = ALIGN(new_size -
4444                                                 found_key.offset,
4445                                                 root->sectorsize);
4446                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4447                                                          extent_num_bytes);
4448                                 num_dec = (orig_num_bytes -
4449                                            extent_num_bytes);
4450                                 if (test_bit(BTRFS_ROOT_REF_COWS,
4451                                              &root->state) &&
4452                                     extent_start != 0)
4453                                         inode_sub_bytes(inode, num_dec);
4454                                 btrfs_mark_buffer_dirty(leaf);
4455                         } else {
4456                                 extent_num_bytes =
4457                                         btrfs_file_extent_disk_num_bytes(leaf,
4458                                                                          fi);
4459                                 extent_offset = found_key.offset -
4460                                         btrfs_file_extent_offset(leaf, fi);
4461
4462                                 /* FIXME blocksize != 4096 */
4463                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4464                                 if (extent_start != 0) {
4465                                         found_extent = 1;
4466                                         if (test_bit(BTRFS_ROOT_REF_COWS,
4467                                                      &root->state))
4468                                                 inode_sub_bytes(inode, num_dec);
4469                                 }
4470                         }
4471                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4472                         /*
4473                          * we can't truncate inline items that have had
4474                          * special encodings
4475                          */
4476                         if (!del_item &&
4477                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4478                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
4479
4480                                 /*
4481                                  * Need to release path in order to truncate a
4482                                  * compressed extent. So delete any accumulated
4483                                  * extent items so far.
4484                                  */
4485                                 if (btrfs_file_extent_compression(leaf, fi) !=
4486                                     BTRFS_COMPRESS_NONE && pending_del_nr) {
4487                                         err = btrfs_del_items(trans, root, path,
4488                                                               pending_del_slot,
4489                                                               pending_del_nr);
4490                                         if (err) {
4491                                                 btrfs_abort_transaction(trans,
4492                                                                         root,
4493                                                                         err);
4494                                                 goto error;
4495                                         }
4496                                         pending_del_nr = 0;
4497                                 }
4498
4499                                 err = truncate_inline_extent(inode, path,
4500                                                              &found_key,
4501                                                              item_end,
4502                                                              new_size);
4503                                 if (err) {
4504                                         btrfs_abort_transaction(trans,
4505                                                                 root, err);
4506                                         goto error;
4507                                 }
4508                         } else if (test_bit(BTRFS_ROOT_REF_COWS,
4509                                             &root->state)) {
4510                                 inode_sub_bytes(inode, item_end + 1 - new_size);
4511                         }
4512                 }
4513 delete:
4514                 if (del_item) {
4515                         if (!pending_del_nr) {
4516                                 /* no pending yet, add ourselves */
4517                                 pending_del_slot = path->slots[0];
4518                                 pending_del_nr = 1;
4519                         } else if (pending_del_nr &&
4520                                    path->slots[0] + 1 == pending_del_slot) {
4521                                 /* hop on the pending chunk */
4522                                 pending_del_nr++;
4523                                 pending_del_slot = path->slots[0];
4524                         } else {
4525                                 BUG();
4526                         }
4527                 } else {
4528                         break;
4529                 }
4530                 should_throttle = 0;
4531
4532                 if (found_extent &&
4533                     (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4534                      root == root->fs_info->tree_root)) {
4535                         btrfs_set_path_blocking(path);
4536                         bytes_deleted += extent_num_bytes;
4537                         ret = btrfs_free_extent(trans, root, extent_start,
4538                                                 extent_num_bytes, 0,
4539                                                 btrfs_header_owner(leaf),
4540                                                 ino, extent_offset);
4541                         BUG_ON(ret);
4542                         if (btrfs_should_throttle_delayed_refs(trans, root))
4543                                 btrfs_async_run_delayed_refs(root,
4544                                         trans->delayed_ref_updates * 2, 0);
4545                         if (be_nice) {
4546                                 if (truncate_space_check(trans, root,
4547                                                          extent_num_bytes)) {
4548                                         should_end = 1;
4549                                 }
4550                                 if (btrfs_should_throttle_delayed_refs(trans,
4551                                                                        root)) {
4552                                         should_throttle = 1;
4553                                 }
4554                         }
4555                 }
4556
4557                 if (found_type == BTRFS_INODE_ITEM_KEY)
4558                         break;
4559
4560                 if (path->slots[0] == 0 ||
4561                     path->slots[0] != pending_del_slot ||
4562                     should_throttle || should_end) {
4563                         if (pending_del_nr) {
4564                                 ret = btrfs_del_items(trans, root, path,
4565                                                 pending_del_slot,
4566                                                 pending_del_nr);
4567                                 if (ret) {
4568                                         btrfs_abort_transaction(trans,
4569                                                                 root, ret);
4570                                         goto error;
4571                                 }
4572                                 pending_del_nr = 0;
4573                         }
4574                         btrfs_release_path(path);
4575                         if (should_throttle) {
4576                                 unsigned long updates = trans->delayed_ref_updates;
4577                                 if (updates) {
4578                                         trans->delayed_ref_updates = 0;
4579                                         ret = btrfs_run_delayed_refs(trans, root, updates * 2);
4580                                         if (ret && !err)
4581                                                 err = ret;
4582                                 }
4583                         }
4584                         /*
4585                          * if we failed to refill our space rsv, bail out
4586                          * and let the transaction restart
4587                          */
4588                         if (should_end) {
4589                                 err = -EAGAIN;
4590                                 goto error;
4591                         }
4592                         goto search_again;
4593                 } else {
4594                         path->slots[0]--;
4595                 }
4596         }
4597 out:
4598         if (pending_del_nr) {
4599                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
4600                                       pending_del_nr);
4601                 if (ret)
4602                         btrfs_abort_transaction(trans, root, ret);
4603         }
4604 error:
4605         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
4606                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4607
4608         btrfs_free_path(path);
4609
4610         if (be_nice && bytes_deleted > 32 * 1024 * 1024) {
4611                 unsigned long updates = trans->delayed_ref_updates;
4612                 if (updates) {
4613                         trans->delayed_ref_updates = 0;
4614                         ret = btrfs_run_delayed_refs(trans, root, updates * 2);
4615                         if (ret && !err)
4616                                 err = ret;
4617                 }
4618         }
4619         return err;
4620 }
4621
4622 /*
4623  * btrfs_truncate_page - read, zero a chunk and write a page
4624  * @inode - inode that we're zeroing
4625  * @from - the offset to start zeroing
4626  * @len - the length to zero, 0 to zero the entire range respective to the
4627  *      offset
4628  * @front - zero up to the offset instead of from the offset on
4629  *
4630  * This will find the page for the "from" offset and cow the page and zero the
4631  * part we want to zero.  This is used with truncate and hole punching.
4632  */
4633 int btrfs_truncate_page(struct inode *inode, loff_t from, loff_t len,
4634                         int front)
4635 {
4636         struct address_space *mapping = inode->i_mapping;
4637         struct btrfs_root *root = BTRFS_I(inode)->root;
4638         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4639         struct btrfs_ordered_extent *ordered;
4640         struct extent_state *cached_state = NULL;
4641         char *kaddr;
4642         u32 blocksize = root->sectorsize;
4643         pgoff_t index = from >> PAGE_CACHE_SHIFT;
4644         unsigned offset = from & (PAGE_CACHE_SIZE-1);
4645         struct page *page;
4646         gfp_t mask = btrfs_alloc_write_mask(mapping);
4647         int ret = 0;
4648         u64 page_start;
4649         u64 page_end;
4650
4651         if ((offset & (blocksize - 1)) == 0 &&
4652             (!len || ((len & (blocksize - 1)) == 0)))
4653                 goto out;
4654         ret = btrfs_delalloc_reserve_space(inode,
4655                         round_down(from, PAGE_CACHE_SIZE), PAGE_CACHE_SIZE);
4656         if (ret)
4657                 goto out;
4658
4659 again:
4660         page = find_or_create_page(mapping, index, mask);
4661         if (!page) {
4662                 btrfs_delalloc_release_space(inode,
4663                                 round_down(from, PAGE_CACHE_SIZE),
4664                                 PAGE_CACHE_SIZE);
4665                 ret = -ENOMEM;
4666                 goto out;
4667         }
4668
4669         page_start = page_offset(page);
4670         page_end = page_start + PAGE_CACHE_SIZE - 1;
4671
4672         if (!PageUptodate(page)) {
4673                 ret = btrfs_readpage(NULL, page);
4674                 lock_page(page);
4675                 if (page->mapping != mapping) {
4676                         unlock_page(page);
4677                         page_cache_release(page);
4678                         goto again;
4679                 }
4680                 if (!PageUptodate(page)) {
4681                         ret = -EIO;
4682                         goto out_unlock;
4683                 }
4684         }
4685         wait_on_page_writeback(page);
4686
4687         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
4688         set_page_extent_mapped(page);
4689
4690         ordered = btrfs_lookup_ordered_extent(inode, page_start);
4691         if (ordered) {
4692                 unlock_extent_cached(io_tree, page_start, page_end,
4693                                      &cached_state, GFP_NOFS);
4694                 unlock_page(page);
4695                 page_cache_release(page);
4696                 btrfs_start_ordered_extent(inode, ordered, 1);
4697                 btrfs_put_ordered_extent(ordered);
4698                 goto again;
4699         }
4700
4701         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
4702                           EXTENT_DIRTY | EXTENT_DELALLOC |
4703                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4704                           0, 0, &cached_state, GFP_NOFS);
4705
4706         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
4707                                         &cached_state);
4708         if (ret) {
4709                 unlock_extent_cached(io_tree, page_start, page_end,
4710                                      &cached_state, GFP_NOFS);
4711                 goto out_unlock;
4712         }
4713
4714         if (offset != PAGE_CACHE_SIZE) {
4715                 if (!len)
4716                         len = PAGE_CACHE_SIZE - offset;
4717                 kaddr = kmap(page);
4718                 if (front)
4719                         memset(kaddr, 0, offset);
4720                 else
4721                         memset(kaddr + offset, 0, len);
4722                 flush_dcache_page(page);
4723                 kunmap(page);
4724         }
4725         ClearPageChecked(page);
4726         set_page_dirty(page);
4727         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
4728                              GFP_NOFS);
4729
4730 out_unlock:
4731         if (ret)
4732                 btrfs_delalloc_release_space(inode, page_start,
4733                                              PAGE_CACHE_SIZE);
4734         unlock_page(page);
4735         page_cache_release(page);
4736 out:
4737         return ret;
4738 }
4739
4740 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4741                              u64 offset, u64 len)
4742 {
4743         struct btrfs_trans_handle *trans;
4744         int ret;
4745
4746         /*
4747          * Still need to make sure the inode looks like it's been updated so
4748          * that any holes get logged if we fsync.
4749          */
4750         if (btrfs_fs_incompat(root->fs_info, NO_HOLES)) {
4751                 BTRFS_I(inode)->last_trans = root->fs_info->generation;
4752                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4753                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4754                 return 0;
4755         }
4756
4757         /*
4758          * 1 - for the one we're dropping
4759          * 1 - for the one we're adding
4760          * 1 - for updating the inode.
4761          */
4762         trans = btrfs_start_transaction(root, 3);
4763         if (IS_ERR(trans))
4764                 return PTR_ERR(trans);
4765
4766         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4767         if (ret) {
4768                 btrfs_abort_transaction(trans, root, ret);
4769                 btrfs_end_transaction(trans, root);
4770                 return ret;
4771         }
4772
4773         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
4774                                        0, 0, len, 0, len, 0, 0, 0);
4775         if (ret)
4776                 btrfs_abort_transaction(trans, root, ret);
4777         else
4778                 btrfs_update_inode(trans, root, inode);
4779         btrfs_end_transaction(trans, root);
4780         return ret;
4781 }
4782
4783 /*
4784  * This function puts in dummy file extents for the area we're creating a hole
4785  * for.  So if we are truncating this file to a larger size we need to insert
4786  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4787  * the range between oldsize and size
4788  */
4789 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4790 {
4791         struct btrfs_root *root = BTRFS_I(inode)->root;
4792         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4793         struct extent_map *em = NULL;
4794         struct extent_state *cached_state = NULL;
4795         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4796         u64 hole_start = ALIGN(oldsize, root->sectorsize);
4797         u64 block_end = ALIGN(size, root->sectorsize);
4798         u64 last_byte;
4799         u64 cur_offset;
4800         u64 hole_size;
4801         int err = 0;
4802
4803         /*
4804          * If our size started in the middle of a page we need to zero out the
4805          * rest of the page before we expand the i_size, otherwise we could
4806          * expose stale data.
4807          */
4808         err = btrfs_truncate_page(inode, oldsize, 0, 0);
4809         if (err)
4810                 return err;
4811
4812         if (size <= hole_start)
4813                 return 0;
4814
4815         while (1) {
4816                 struct btrfs_ordered_extent *ordered;
4817
4818                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
4819                                  &cached_state);
4820                 ordered = btrfs_lookup_ordered_range(inode, hole_start,
4821                                                      block_end - hole_start);
4822                 if (!ordered)
4823                         break;
4824                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
4825                                      &cached_state, GFP_NOFS);
4826                 btrfs_start_ordered_extent(inode, ordered, 1);
4827                 btrfs_put_ordered_extent(ordered);
4828         }
4829
4830         cur_offset = hole_start;
4831         while (1) {
4832                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
4833                                 block_end - cur_offset, 0);
4834                 if (IS_ERR(em)) {
4835                         err = PTR_ERR(em);
4836                         em = NULL;
4837                         break;
4838                 }
4839                 last_byte = min(extent_map_end(em), block_end);
4840                 last_byte = ALIGN(last_byte , root->sectorsize);
4841                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4842                         struct extent_map *hole_em;
4843                         hole_size = last_byte - cur_offset;
4844
4845                         err = maybe_insert_hole(root, inode, cur_offset,
4846                                                 hole_size);
4847                         if (err)
4848                                 break;
4849                         btrfs_drop_extent_cache(inode, cur_offset,
4850                                                 cur_offset + hole_size - 1, 0);
4851                         hole_em = alloc_extent_map();
4852                         if (!hole_em) {
4853                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4854                                         &BTRFS_I(inode)->runtime_flags);
4855                                 goto next;
4856                         }
4857                         hole_em->start = cur_offset;
4858                         hole_em->len = hole_size;
4859                         hole_em->orig_start = cur_offset;
4860
4861                         hole_em->block_start = EXTENT_MAP_HOLE;
4862                         hole_em->block_len = 0;
4863                         hole_em->orig_block_len = 0;
4864                         hole_em->ram_bytes = hole_size;
4865                         hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
4866                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4867                         hole_em->generation = root->fs_info->generation;
4868
4869                         while (1) {
4870                                 write_lock(&em_tree->lock);
4871                                 err = add_extent_mapping(em_tree, hole_em, 1);
4872                                 write_unlock(&em_tree->lock);
4873                                 if (err != -EEXIST)
4874                                         break;
4875                                 btrfs_drop_extent_cache(inode, cur_offset,
4876                                                         cur_offset +
4877                                                         hole_size - 1, 0);
4878                         }
4879                         free_extent_map(hole_em);
4880                 }
4881 next:
4882                 free_extent_map(em);
4883                 em = NULL;
4884                 cur_offset = last_byte;
4885                 if (cur_offset >= block_end)
4886                         break;
4887         }
4888         free_extent_map(em);
4889         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
4890                              GFP_NOFS);
4891         return err;
4892 }
4893
4894 static int wait_snapshoting_atomic_t(atomic_t *a)
4895 {
4896         schedule();
4897         return 0;
4898 }
4899
4900 static void wait_for_snapshot_creation(struct btrfs_root *root)
4901 {
4902         while (true) {
4903                 int ret;
4904
4905                 ret = btrfs_start_write_no_snapshoting(root);
4906                 if (ret)
4907                         break;
4908                 wait_on_atomic_t(&root->will_be_snapshoted,
4909                                  wait_snapshoting_atomic_t,
4910                                  TASK_UNINTERRUPTIBLE);
4911         }
4912 }
4913
4914 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4915 {
4916         struct btrfs_root *root = BTRFS_I(inode)->root;
4917         struct btrfs_trans_handle *trans;
4918         loff_t oldsize = i_size_read(inode);
4919         loff_t newsize = attr->ia_size;
4920         int mask = attr->ia_valid;
4921         int ret;
4922
4923         /*
4924          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4925          * special case where we need to update the times despite not having
4926          * these flags set.  For all other operations the VFS set these flags
4927          * explicitly if it wants a timestamp update.
4928          */
4929         if (newsize != oldsize) {
4930                 inode_inc_iversion(inode);
4931                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
4932                         inode->i_ctime = inode->i_mtime =
4933                                 current_fs_time(inode->i_sb);
4934         }
4935
4936         if (newsize > oldsize) {
4937                 truncate_pagecache(inode, newsize);
4938                 /*
4939                  * Don't do an expanding truncate while snapshoting is ongoing.
4940                  * This is to ensure the snapshot captures a fully consistent
4941                  * state of this file - if the snapshot captures this expanding
4942                  * truncation, it must capture all writes that happened before
4943                  * this truncation.
4944                  */
4945                 wait_for_snapshot_creation(root);
4946                 ret = btrfs_cont_expand(inode, oldsize, newsize);
4947                 if (ret) {
4948                         btrfs_end_write_no_snapshoting(root);
4949                         return ret;
4950                 }
4951
4952                 trans = btrfs_start_transaction(root, 1);
4953                 if (IS_ERR(trans)) {
4954                         btrfs_end_write_no_snapshoting(root);
4955                         return PTR_ERR(trans);
4956                 }
4957
4958                 i_size_write(inode, newsize);
4959                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
4960                 ret = btrfs_update_inode(trans, root, inode);
4961                 btrfs_end_write_no_snapshoting(root);
4962                 btrfs_end_transaction(trans, root);
4963         } else {
4964
4965                 /*
4966                  * We're truncating a file that used to have good data down to
4967                  * zero. Make sure it gets into the ordered flush list so that
4968                  * any new writes get down to disk quickly.
4969                  */
4970                 if (newsize == 0)
4971                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
4972                                 &BTRFS_I(inode)->runtime_flags);
4973
4974                 /*
4975                  * 1 for the orphan item we're going to add
4976                  * 1 for the orphan item deletion.
4977                  */
4978                 trans = btrfs_start_transaction(root, 2);
4979                 if (IS_ERR(trans))
4980                         return PTR_ERR(trans);
4981
4982                 /*
4983                  * We need to do this in case we fail at _any_ point during the
4984                  * actual truncate.  Once we do the truncate_setsize we could
4985                  * invalidate pages which forces any outstanding ordered io to
4986                  * be instantly completed which will give us extents that need
4987                  * to be truncated.  If we fail to get an orphan inode down we
4988                  * could have left over extents that were never meant to live,
4989                  * so we need to garuntee from this point on that everything
4990                  * will be consistent.
4991                  */
4992                 ret = btrfs_orphan_add(trans, inode);
4993                 btrfs_end_transaction(trans, root);
4994                 if (ret)
4995                         return ret;
4996
4997                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
4998                 truncate_setsize(inode, newsize);
4999
5000                 /* Disable nonlocked read DIO to avoid the end less truncate */
5001                 btrfs_inode_block_unlocked_dio(inode);
5002                 inode_dio_wait(inode);
5003                 btrfs_inode_resume_unlocked_dio(inode);
5004
5005                 ret = btrfs_truncate(inode);
5006                 if (ret && inode->i_nlink) {
5007                         int err;
5008
5009                         /*
5010                          * failed to truncate, disk_i_size is only adjusted down
5011                          * as we remove extents, so it should represent the true
5012                          * size of the inode, so reset the in memory size and
5013                          * delete our orphan entry.
5014                          */
5015                         trans = btrfs_join_transaction(root);
5016                         if (IS_ERR(trans)) {
5017                                 btrfs_orphan_del(NULL, inode);
5018                                 return ret;
5019                         }
5020                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
5021                         err = btrfs_orphan_del(trans, inode);
5022                         if (err)
5023                                 btrfs_abort_transaction(trans, root, err);
5024                         btrfs_end_transaction(trans, root);
5025                 }
5026         }
5027
5028         return ret;
5029 }
5030
5031 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
5032 {
5033         struct inode *inode = d_inode(dentry);
5034         struct btrfs_root *root = BTRFS_I(inode)->root;
5035         int err;
5036
5037         if (btrfs_root_readonly(root))
5038                 return -EROFS;
5039
5040         err = inode_change_ok(inode, attr);
5041         if (err)
5042                 return err;
5043
5044         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
5045                 err = btrfs_setsize(inode, attr);
5046                 if (err)
5047                         return err;
5048         }
5049
5050         if (attr->ia_valid) {
5051                 setattr_copy(inode, attr);
5052                 inode_inc_iversion(inode);
5053                 err = btrfs_dirty_inode(inode);
5054
5055                 if (!err && attr->ia_valid & ATTR_MODE)
5056                         err = posix_acl_chmod(inode, inode->i_mode);
5057         }
5058
5059         return err;
5060 }
5061
5062 /*
5063  * While truncating the inode pages during eviction, we get the VFS calling
5064  * btrfs_invalidatepage() against each page of the inode. This is slow because
5065  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
5066  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
5067  * extent_state structures over and over, wasting lots of time.
5068  *
5069  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
5070  * those expensive operations on a per page basis and do only the ordered io
5071  * finishing, while we release here the extent_map and extent_state structures,
5072  * without the excessive merging and splitting.
5073  */
5074 static void evict_inode_truncate_pages(struct inode *inode)
5075 {
5076         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5077         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
5078         struct rb_node *node;
5079
5080         ASSERT(inode->i_state & I_FREEING);
5081         truncate_inode_pages_final(&inode->i_data);
5082
5083         write_lock(&map_tree->lock);
5084         while (!RB_EMPTY_ROOT(&map_tree->map)) {
5085                 struct extent_map *em;
5086
5087                 node = rb_first(&map_tree->map);
5088                 em = rb_entry(node, struct extent_map, rb_node);
5089                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
5090                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
5091                 remove_extent_mapping(map_tree, em);
5092                 free_extent_map(em);
5093                 if (need_resched()) {
5094                         write_unlock(&map_tree->lock);
5095                         cond_resched();
5096                         write_lock(&map_tree->lock);
5097                 }
5098         }
5099         write_unlock(&map_tree->lock);
5100
5101         /*
5102          * Keep looping until we have no more ranges in the io tree.
5103          * We can have ongoing bios started by readpages (called from readahead)
5104          * that have their endio callback (extent_io.c:end_bio_extent_readpage)
5105          * still in progress (unlocked the pages in the bio but did not yet
5106          * unlocked the ranges in the io tree). Therefore this means some
5107          * ranges can still be locked and eviction started because before
5108          * submitting those bios, which are executed by a separate task (work
5109          * queue kthread), inode references (inode->i_count) were not taken
5110          * (which would be dropped in the end io callback of each bio).
5111          * Therefore here we effectively end up waiting for those bios and
5112          * anyone else holding locked ranges without having bumped the inode's
5113          * reference count - if we don't do it, when they access the inode's
5114          * io_tree to unlock a range it may be too late, leading to an
5115          * use-after-free issue.
5116          */
5117         spin_lock(&io_tree->lock);
5118         while (!RB_EMPTY_ROOT(&io_tree->state)) {
5119                 struct extent_state *state;
5120                 struct extent_state *cached_state = NULL;
5121                 u64 start;
5122                 u64 end;
5123
5124                 node = rb_first(&io_tree->state);
5125                 state = rb_entry(node, struct extent_state, rb_node);
5126                 start = state->start;
5127                 end = state->end;
5128                 spin_unlock(&io_tree->lock);
5129
5130                 lock_extent_bits(io_tree, start, end, 0, &cached_state);
5131
5132                 /*
5133                  * If still has DELALLOC flag, the extent didn't reach disk,
5134                  * and its reserved space won't be freed by delayed_ref.
5135                  * So we need to free its reserved space here.
5136                  * (Refer to comment in btrfs_invalidatepage, case 2)
5137                  *
5138                  * Note, end is the bytenr of last byte, so we need + 1 here.
5139                  */
5140                 if (state->state & EXTENT_DELALLOC)
5141                         btrfs_qgroup_free_data(inode, start, end - start + 1);
5142
5143                 clear_extent_bit(io_tree, start, end,
5144                                  EXTENT_LOCKED | EXTENT_DIRTY |
5145                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
5146                                  EXTENT_DEFRAG, 1, 1,
5147                                  &cached_state, GFP_NOFS);
5148
5149                 cond_resched();
5150                 spin_lock(&io_tree->lock);
5151         }
5152         spin_unlock(&io_tree->lock);
5153 }
5154
5155 void btrfs_evict_inode(struct inode *inode)
5156 {
5157         struct btrfs_trans_handle *trans;
5158         struct btrfs_root *root = BTRFS_I(inode)->root;
5159         struct btrfs_block_rsv *rsv, *global_rsv;
5160         int steal_from_global = 0;
5161         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
5162         int ret;
5163
5164         trace_btrfs_inode_evict(inode);
5165
5166         evict_inode_truncate_pages(inode);
5167
5168         if (inode->i_nlink &&
5169             ((btrfs_root_refs(&root->root_item) != 0 &&
5170               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
5171              btrfs_is_free_space_inode(inode)))
5172                 goto no_delete;
5173
5174         if (is_bad_inode(inode)) {
5175                 btrfs_orphan_del(NULL, inode);
5176                 goto no_delete;
5177         }
5178         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
5179         if (!special_file(inode->i_mode))
5180                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
5181
5182         btrfs_free_io_failure_record(inode, 0, (u64)-1);
5183
5184         if (root->fs_info->log_root_recovering) {
5185                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
5186                                  &BTRFS_I(inode)->runtime_flags));
5187                 goto no_delete;
5188         }
5189
5190         if (inode->i_nlink > 0) {
5191                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
5192                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
5193                 goto no_delete;
5194         }
5195
5196         ret = btrfs_commit_inode_delayed_inode(inode);
5197         if (ret) {
5198                 btrfs_orphan_del(NULL, inode);
5199                 goto no_delete;
5200         }
5201
5202         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
5203         if (!rsv) {
5204                 btrfs_orphan_del(NULL, inode);
5205                 goto no_delete;
5206         }
5207         rsv->size = min_size;
5208         rsv->failfast = 1;
5209         global_rsv = &root->fs_info->global_block_rsv;
5210
5211         btrfs_i_size_write(inode, 0);
5212
5213         /*
5214          * This is a bit simpler than btrfs_truncate since we've already
5215          * reserved our space for our orphan item in the unlink, so we just
5216          * need to reserve some slack space in case we add bytes and update
5217          * inode item when doing the truncate.
5218          */
5219         while (1) {
5220                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
5221                                              BTRFS_RESERVE_FLUSH_LIMIT);
5222
5223                 /*
5224                  * Try and steal from the global reserve since we will
5225                  * likely not use this space anyway, we want to try as
5226                  * hard as possible to get this to work.
5227                  */
5228                 if (ret)
5229                         steal_from_global++;
5230                 else
5231                         steal_from_global = 0;
5232                 ret = 0;
5233
5234                 /*
5235                  * steal_from_global == 0: we reserved stuff, hooray!
5236                  * steal_from_global == 1: we didn't reserve stuff, boo!
5237                  * steal_from_global == 2: we've committed, still not a lot of
5238                  * room but maybe we'll have room in the global reserve this
5239                  * time.
5240                  * steal_from_global == 3: abandon all hope!
5241                  */
5242                 if (steal_from_global > 2) {
5243                         btrfs_warn(root->fs_info,
5244                                 "Could not get space for a delete, will truncate on mount %d",
5245                                 ret);
5246                         btrfs_orphan_del(NULL, inode);
5247                         btrfs_free_block_rsv(root, rsv);
5248                         goto no_delete;
5249                 }
5250
5251                 trans = btrfs_join_transaction(root);
5252                 if (IS_ERR(trans)) {
5253                         btrfs_orphan_del(NULL, inode);
5254                         btrfs_free_block_rsv(root, rsv);
5255                         goto no_delete;
5256                 }
5257
5258                 /*
5259                  * We can't just steal from the global reserve, we need tomake
5260                  * sure there is room to do it, if not we need to commit and try
5261                  * again.
5262                  */
5263                 if (steal_from_global) {
5264                         if (!btrfs_check_space_for_delayed_refs(trans, root))
5265                                 ret = btrfs_block_rsv_migrate(global_rsv, rsv,
5266                                                               min_size);
5267                         else
5268                                 ret = -ENOSPC;
5269                 }
5270
5271                 /*
5272                  * Couldn't steal from the global reserve, we have too much
5273                  * pending stuff built up, commit the transaction and try it
5274                  * again.
5275                  */
5276                 if (ret) {
5277                         ret = btrfs_commit_transaction(trans, root);
5278                         if (ret) {
5279                                 btrfs_orphan_del(NULL, inode);
5280                                 btrfs_free_block_rsv(root, rsv);
5281                                 goto no_delete;
5282                         }
5283                         continue;
5284                 } else {
5285                         steal_from_global = 0;
5286                 }
5287
5288                 trans->block_rsv = rsv;
5289
5290                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
5291                 if (ret != -ENOSPC && ret != -EAGAIN)
5292                         break;
5293
5294                 trans->block_rsv = &root->fs_info->trans_block_rsv;
5295                 btrfs_end_transaction(trans, root);
5296                 trans = NULL;
5297                 btrfs_btree_balance_dirty(root);
5298         }
5299
5300         btrfs_free_block_rsv(root, rsv);
5301
5302         /*
5303          * Errors here aren't a big deal, it just means we leave orphan items
5304          * in the tree.  They will be cleaned up on the next mount.
5305          */
5306         if (ret == 0) {
5307                 trans->block_rsv = root->orphan_block_rsv;
5308                 btrfs_orphan_del(trans, inode);
5309         } else {
5310                 btrfs_orphan_del(NULL, inode);
5311         }
5312
5313         trans->block_rsv = &root->fs_info->trans_block_rsv;
5314         if (!(root == root->fs_info->tree_root ||
5315               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
5316                 btrfs_return_ino(root, btrfs_ino(inode));
5317
5318         btrfs_end_transaction(trans, root);
5319         btrfs_btree_balance_dirty(root);
5320 no_delete:
5321         btrfs_remove_delayed_node(inode);
5322         clear_inode(inode);
5323         return;
5324 }
5325
5326 /*
5327  * this returns the key found in the dir entry in the location pointer.
5328  * If no dir entries were found, location->objectid is 0.
5329  */
5330 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
5331                                struct btrfs_key *location)
5332 {
5333         const char *name = dentry->d_name.name;
5334         int namelen = dentry->d_name.len;
5335         struct btrfs_dir_item *di;
5336         struct btrfs_path *path;
5337         struct btrfs_root *root = BTRFS_I(dir)->root;
5338         int ret = 0;
5339
5340         path = btrfs_alloc_path();
5341         if (!path)
5342                 return -ENOMEM;
5343
5344         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
5345                                     namelen, 0);
5346         if (IS_ERR(di))
5347                 ret = PTR_ERR(di);
5348
5349         if (IS_ERR_OR_NULL(di))
5350                 goto out_err;
5351
5352         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
5353 out:
5354         btrfs_free_path(path);
5355         return ret;
5356 out_err:
5357         location->objectid = 0;
5358         goto out;
5359 }
5360
5361 /*
5362  * when we hit a tree root in a directory, the btrfs part of the inode
5363  * needs to be changed to reflect the root directory of the tree root.  This
5364  * is kind of like crossing a mount point.
5365  */
5366 static int fixup_tree_root_location(struct btrfs_root *root,
5367                                     struct inode *dir,
5368                                     struct dentry *dentry,
5369                                     struct btrfs_key *location,
5370                                     struct btrfs_root **sub_root)
5371 {
5372         struct btrfs_path *path;
5373         struct btrfs_root *new_root;
5374         struct btrfs_root_ref *ref;
5375         struct extent_buffer *leaf;
5376         struct btrfs_key key;
5377         int ret;
5378         int err = 0;
5379
5380         path = btrfs_alloc_path();
5381         if (!path) {
5382                 err = -ENOMEM;
5383                 goto out;
5384         }
5385
5386         err = -ENOENT;
5387         key.objectid = BTRFS_I(dir)->root->root_key.objectid;
5388         key.type = BTRFS_ROOT_REF_KEY;
5389         key.offset = location->objectid;
5390
5391         ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key, path,
5392                                 0, 0);
5393         if (ret) {
5394                 if (ret < 0)
5395                         err = ret;
5396                 goto out;
5397         }
5398
5399         leaf = path->nodes[0];
5400         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
5401         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
5402             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
5403                 goto out;
5404
5405         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
5406                                    (unsigned long)(ref + 1),
5407                                    dentry->d_name.len);
5408         if (ret)
5409                 goto out;
5410
5411         btrfs_release_path(path);
5412
5413         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
5414         if (IS_ERR(new_root)) {
5415                 err = PTR_ERR(new_root);
5416                 goto out;
5417         }
5418
5419         *sub_root = new_root;
5420         location->objectid = btrfs_root_dirid(&new_root->root_item);
5421         location->type = BTRFS_INODE_ITEM_KEY;
5422         location->offset = 0;
5423         err = 0;
5424 out:
5425         btrfs_free_path(path);
5426         return err;
5427 }
5428
5429 static void inode_tree_add(struct inode *inode)
5430 {
5431         struct btrfs_root *root = BTRFS_I(inode)->root;
5432         struct btrfs_inode *entry;
5433         struct rb_node **p;
5434         struct rb_node *parent;
5435         struct rb_node *new = &BTRFS_I(inode)->rb_node;
5436         u64 ino = btrfs_ino(inode);
5437
5438         if (inode_unhashed(inode))
5439                 return;
5440         parent = NULL;
5441         spin_lock(&root->inode_lock);
5442         p = &root->inode_tree.rb_node;
5443         while (*p) {
5444                 parent = *p;
5445                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
5446
5447                 if (ino < btrfs_ino(&entry->vfs_inode))
5448                         p = &parent->rb_left;
5449                 else if (ino > btrfs_ino(&entry->vfs_inode))
5450                         p = &parent->rb_right;
5451                 else {
5452                         WARN_ON(!(entry->vfs_inode.i_state &
5453                                   (I_WILL_FREE | I_FREEING)));
5454                         rb_replace_node(parent, new, &root->inode_tree);
5455                         RB_CLEAR_NODE(parent);
5456                         spin_unlock(&root->inode_lock);
5457                         return;
5458                 }
5459         }
5460         rb_link_node(new, parent, p);
5461         rb_insert_color(new, &root->inode_tree);
5462         spin_unlock(&root->inode_lock);
5463 }
5464
5465 static void inode_tree_del(struct inode *inode)
5466 {
5467         struct btrfs_root *root = BTRFS_I(inode)->root;
5468         int empty = 0;
5469
5470         spin_lock(&root->inode_lock);
5471         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
5472                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
5473                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
5474                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5475         }
5476         spin_unlock(&root->inode_lock);
5477
5478         if (empty && btrfs_root_refs(&root->root_item) == 0) {
5479                 synchronize_srcu(&root->fs_info->subvol_srcu);
5480                 spin_lock(&root->inode_lock);
5481                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5482                 spin_unlock(&root->inode_lock);
5483                 if (empty)
5484                         btrfs_add_dead_root(root);
5485         }
5486 }
5487
5488 void btrfs_invalidate_inodes(struct btrfs_root *root)
5489 {
5490         struct rb_node *node;
5491         struct rb_node *prev;
5492         struct btrfs_inode *entry;
5493         struct inode *inode;
5494         u64 objectid = 0;
5495
5496         if (!test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
5497                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
5498
5499         spin_lock(&root->inode_lock);
5500 again:
5501         node = root->inode_tree.rb_node;
5502         prev = NULL;
5503         while (node) {
5504                 prev = node;
5505                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5506
5507                 if (objectid < btrfs_ino(&entry->vfs_inode))
5508                         node = node->rb_left;
5509                 else if (objectid > btrfs_ino(&entry->vfs_inode))
5510                         node = node->rb_right;
5511                 else
5512                         break;
5513         }
5514         if (!node) {
5515                 while (prev) {
5516                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
5517                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
5518                                 node = prev;
5519                                 break;
5520                         }
5521                         prev = rb_next(prev);
5522                 }
5523         }
5524         while (node) {
5525                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5526                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
5527                 inode = igrab(&entry->vfs_inode);
5528                 if (inode) {
5529                         spin_unlock(&root->inode_lock);
5530                         if (atomic_read(&inode->i_count) > 1)
5531                                 d_prune_aliases(inode);
5532                         /*
5533                          * btrfs_drop_inode will have it removed from
5534                          * the inode cache when its usage count
5535                          * hits zero.
5536                          */
5537                         iput(inode);
5538                         cond_resched();
5539                         spin_lock(&root->inode_lock);
5540                         goto again;
5541                 }
5542
5543                 if (cond_resched_lock(&root->inode_lock))
5544                         goto again;
5545
5546                 node = rb_next(node);
5547         }
5548         spin_unlock(&root->inode_lock);
5549 }
5550
5551 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5552 {
5553         struct btrfs_iget_args *args = p;
5554         inode->i_ino = args->location->objectid;
5555         memcpy(&BTRFS_I(inode)->location, args->location,
5556                sizeof(*args->location));
5557         BTRFS_I(inode)->root = args->root;
5558         return 0;
5559 }
5560
5561 static int btrfs_find_actor(struct inode *inode, void *opaque)
5562 {
5563         struct btrfs_iget_args *args = opaque;
5564         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5565                 args->root == BTRFS_I(inode)->root;
5566 }
5567
5568 static struct inode *btrfs_iget_locked(struct super_block *s,
5569                                        struct btrfs_key *location,
5570                                        struct btrfs_root *root)
5571 {
5572         struct inode *inode;
5573         struct btrfs_iget_args args;
5574         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5575
5576         args.location = location;
5577         args.root = root;
5578
5579         inode = iget5_locked(s, hashval, btrfs_find_actor,
5580                              btrfs_init_locked_inode,
5581                              (void *)&args);
5582         return inode;
5583 }
5584
5585 /* Get an inode object given its location and corresponding root.
5586  * Returns in *is_new if the inode was read from disk
5587  */
5588 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5589                          struct btrfs_root *root, int *new)
5590 {
5591         struct inode *inode;
5592
5593         inode = btrfs_iget_locked(s, location, root);
5594         if (!inode)
5595                 return ERR_PTR(-ENOMEM);
5596
5597         if (inode->i_state & I_NEW) {
5598                 btrfs_read_locked_inode(inode);
5599                 if (!is_bad_inode(inode)) {
5600                         inode_tree_add(inode);
5601                         unlock_new_inode(inode);
5602                         if (new)
5603                                 *new = 1;
5604                 } else {
5605                         unlock_new_inode(inode);
5606                         iput(inode);
5607                         inode = ERR_PTR(-ESTALE);
5608                 }
5609         }
5610
5611         return inode;
5612 }
5613
5614 static struct inode *new_simple_dir(struct super_block *s,
5615                                     struct btrfs_key *key,
5616                                     struct btrfs_root *root)
5617 {
5618         struct inode *inode = new_inode(s);
5619
5620         if (!inode)
5621                 return ERR_PTR(-ENOMEM);
5622
5623         BTRFS_I(inode)->root = root;
5624         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5625         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5626
5627         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5628         inode->i_op = &btrfs_dir_ro_inode_operations;
5629         inode->i_fop = &simple_dir_operations;
5630         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5631         inode->i_mtime = CURRENT_TIME;
5632         inode->i_atime = inode->i_mtime;
5633         inode->i_ctime = inode->i_mtime;
5634         BTRFS_I(inode)->i_otime = inode->i_mtime;
5635
5636         return inode;
5637 }
5638
5639 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5640 {
5641         struct inode *inode;
5642         struct btrfs_root *root = BTRFS_I(dir)->root;
5643         struct btrfs_root *sub_root = root;
5644         struct btrfs_key location;
5645         int index;
5646         int ret = 0;
5647
5648         if (dentry->d_name.len > BTRFS_NAME_LEN)
5649                 return ERR_PTR(-ENAMETOOLONG);
5650
5651         ret = btrfs_inode_by_name(dir, dentry, &location);
5652         if (ret < 0)
5653                 return ERR_PTR(ret);
5654
5655         if (location.objectid == 0)
5656                 return ERR_PTR(-ENOENT);
5657
5658         if (location.type == BTRFS_INODE_ITEM_KEY) {
5659                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5660                 return inode;
5661         }
5662
5663         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
5664
5665         index = srcu_read_lock(&root->fs_info->subvol_srcu);
5666         ret = fixup_tree_root_location(root, dir, dentry,
5667                                        &location, &sub_root);
5668         if (ret < 0) {
5669                 if (ret != -ENOENT)
5670                         inode = ERR_PTR(ret);
5671                 else
5672                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5673         } else {
5674                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5675         }
5676         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
5677
5678         if (!IS_ERR(inode) && root != sub_root) {
5679                 down_read(&root->fs_info->cleanup_work_sem);
5680                 if (!(inode->i_sb->s_flags & MS_RDONLY))
5681                         ret = btrfs_orphan_cleanup(sub_root);
5682                 up_read(&root->fs_info->cleanup_work_sem);
5683                 if (ret) {
5684                         iput(inode);
5685                         inode = ERR_PTR(ret);
5686                 }
5687         }
5688
5689         return inode;
5690 }
5691
5692 static int btrfs_dentry_delete(const struct dentry *dentry)
5693 {
5694         struct btrfs_root *root;
5695         struct inode *inode = d_inode(dentry);
5696
5697         if (!inode && !IS_ROOT(dentry))
5698                 inode = d_inode(dentry->d_parent);
5699
5700         if (inode) {
5701                 root = BTRFS_I(inode)->root;
5702                 if (btrfs_root_refs(&root->root_item) == 0)
5703                         return 1;
5704
5705                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5706                         return 1;
5707         }
5708         return 0;
5709 }
5710
5711 static void btrfs_dentry_release(struct dentry *dentry)
5712 {
5713         kfree(dentry->d_fsdata);
5714 }
5715
5716 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5717                                    unsigned int flags)
5718 {
5719         struct inode *inode;
5720
5721         inode = btrfs_lookup_dentry(dir, dentry);
5722         if (IS_ERR(inode)) {
5723                 if (PTR_ERR(inode) == -ENOENT)
5724                         inode = NULL;
5725                 else
5726                         return ERR_CAST(inode);
5727         }
5728
5729         return d_splice_alias(inode, dentry);
5730 }
5731
5732 unsigned char btrfs_filetype_table[] = {
5733         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5734 };
5735
5736 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5737 {
5738         struct inode *inode = file_inode(file);
5739         struct btrfs_root *root = BTRFS_I(inode)->root;
5740         struct btrfs_item *item;
5741         struct btrfs_dir_item *di;
5742         struct btrfs_key key;
5743         struct btrfs_key found_key;
5744         struct btrfs_path *path;
5745         struct list_head ins_list;
5746         struct list_head del_list;
5747         int ret;
5748         struct extent_buffer *leaf;
5749         int slot;
5750         unsigned char d_type;
5751         int over = 0;
5752         u32 di_cur;
5753         u32 di_total;
5754         u32 di_len;
5755         int key_type = BTRFS_DIR_INDEX_KEY;
5756         char tmp_name[32];
5757         char *name_ptr;
5758         int name_len;
5759         int is_curr = 0;        /* ctx->pos points to the current index? */
5760
5761         /* FIXME, use a real flag for deciding about the key type */
5762         if (root->fs_info->tree_root == root)
5763                 key_type = BTRFS_DIR_ITEM_KEY;
5764
5765         if (!dir_emit_dots(file, ctx))
5766                 return 0;
5767
5768         path = btrfs_alloc_path();
5769         if (!path)
5770                 return -ENOMEM;
5771
5772         path->reada = 1;
5773
5774         if (key_type == BTRFS_DIR_INDEX_KEY) {
5775                 INIT_LIST_HEAD(&ins_list);
5776                 INIT_LIST_HEAD(&del_list);
5777                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
5778         }
5779
5780         key.type = key_type;
5781         key.offset = ctx->pos;
5782         key.objectid = btrfs_ino(inode);
5783
5784         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5785         if (ret < 0)
5786                 goto err;
5787
5788         while (1) {
5789                 leaf = path->nodes[0];
5790                 slot = path->slots[0];
5791                 if (slot >= btrfs_header_nritems(leaf)) {
5792                         ret = btrfs_next_leaf(root, path);
5793                         if (ret < 0)
5794                                 goto err;
5795                         else if (ret > 0)
5796                                 break;
5797                         continue;
5798                 }
5799
5800                 item = btrfs_item_nr(slot);
5801                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5802
5803                 if (found_key.objectid != key.objectid)
5804                         break;
5805                 if (found_key.type != key_type)
5806                         break;
5807                 if (found_key.offset < ctx->pos)
5808                         goto next;
5809                 if (key_type == BTRFS_DIR_INDEX_KEY &&
5810                     btrfs_should_delete_dir_index(&del_list,
5811                                                   found_key.offset))
5812                         goto next;
5813
5814                 ctx->pos = found_key.offset;
5815                 is_curr = 1;
5816
5817                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5818                 di_cur = 0;
5819                 di_total = btrfs_item_size(leaf, item);
5820
5821                 while (di_cur < di_total) {
5822                         struct btrfs_key location;
5823
5824                         if (verify_dir_item(root, leaf, di))
5825                                 break;
5826
5827                         name_len = btrfs_dir_name_len(leaf, di);
5828                         if (name_len <= sizeof(tmp_name)) {
5829                                 name_ptr = tmp_name;
5830                         } else {
5831                                 name_ptr = kmalloc(name_len, GFP_NOFS);
5832                                 if (!name_ptr) {
5833                                         ret = -ENOMEM;
5834                                         goto err;
5835                                 }
5836                         }
5837                         read_extent_buffer(leaf, name_ptr,
5838                                            (unsigned long)(di + 1), name_len);
5839
5840                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
5841                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
5842
5843
5844                         /* is this a reference to our own snapshot? If so
5845                          * skip it.
5846                          *
5847                          * In contrast to old kernels, we insert the snapshot's
5848                          * dir item and dir index after it has been created, so
5849                          * we won't find a reference to our own snapshot. We
5850                          * still keep the following code for backward
5851                          * compatibility.
5852                          */
5853                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
5854                             location.objectid == root->root_key.objectid) {
5855                                 over = 0;
5856                                 goto skip;
5857                         }
5858                         over = !dir_emit(ctx, name_ptr, name_len,
5859                                        location.objectid, d_type);
5860
5861 skip:
5862                         if (name_ptr != tmp_name)
5863                                 kfree(name_ptr);
5864
5865                         if (over)
5866                                 goto nopos;
5867                         di_len = btrfs_dir_name_len(leaf, di) +
5868                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
5869                         di_cur += di_len;
5870                         di = (struct btrfs_dir_item *)((char *)di + di_len);
5871                 }
5872 next:
5873                 path->slots[0]++;
5874         }
5875
5876         if (key_type == BTRFS_DIR_INDEX_KEY) {
5877                 if (is_curr)
5878                         ctx->pos++;
5879                 ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5880                 if (ret)
5881                         goto nopos;
5882         }
5883
5884         /* Reached end of directory/root. Bump pos past the last item. */
5885         ctx->pos++;
5886
5887         /*
5888          * Stop new entries from being returned after we return the last
5889          * entry.
5890          *
5891          * New directory entries are assigned a strictly increasing
5892          * offset.  This means that new entries created during readdir
5893          * are *guaranteed* to be seen in the future by that readdir.
5894          * This has broken buggy programs which operate on names as
5895          * they're returned by readdir.  Until we re-use freed offsets
5896          * we have this hack to stop new entries from being returned
5897          * under the assumption that they'll never reach this huge
5898          * offset.
5899          *
5900          * This is being careful not to overflow 32bit loff_t unless the
5901          * last entry requires it because doing so has broken 32bit apps
5902          * in the past.
5903          */
5904         if (key_type == BTRFS_DIR_INDEX_KEY) {
5905                 if (ctx->pos >= INT_MAX)
5906                         ctx->pos = LLONG_MAX;
5907                 else
5908                         ctx->pos = INT_MAX;
5909         }
5910 nopos:
5911         ret = 0;
5912 err:
5913         if (key_type == BTRFS_DIR_INDEX_KEY)
5914                 btrfs_put_delayed_items(&ins_list, &del_list);
5915         btrfs_free_path(path);
5916         return ret;
5917 }
5918
5919 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
5920 {
5921         struct btrfs_root *root = BTRFS_I(inode)->root;
5922         struct btrfs_trans_handle *trans;
5923         int ret = 0;
5924         bool nolock = false;
5925
5926         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5927                 return 0;
5928
5929         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
5930                 nolock = true;
5931
5932         if (wbc->sync_mode == WB_SYNC_ALL) {
5933                 if (nolock)
5934                         trans = btrfs_join_transaction_nolock(root);
5935                 else
5936                         trans = btrfs_join_transaction(root);
5937                 if (IS_ERR(trans))
5938                         return PTR_ERR(trans);
5939                 ret = btrfs_commit_transaction(trans, root);
5940         }
5941         return ret;
5942 }
5943
5944 /*
5945  * This is somewhat expensive, updating the tree every time the
5946  * inode changes.  But, it is most likely to find the inode in cache.
5947  * FIXME, needs more benchmarking...there are no reasons other than performance
5948  * to keep or drop this code.
5949  */
5950 static int btrfs_dirty_inode(struct inode *inode)
5951 {
5952         struct btrfs_root *root = BTRFS_I(inode)->root;
5953         struct btrfs_trans_handle *trans;
5954         int ret;
5955
5956         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5957                 return 0;
5958
5959         trans = btrfs_join_transaction(root);
5960         if (IS_ERR(trans))
5961                 return PTR_ERR(trans);
5962
5963         ret = btrfs_update_inode(trans, root, inode);
5964         if (ret && ret == -ENOSPC) {
5965                 /* whoops, lets try again with the full transaction */
5966                 btrfs_end_transaction(trans, root);
5967                 trans = btrfs_start_transaction(root, 1);
5968                 if (IS_ERR(trans))
5969                         return PTR_ERR(trans);
5970
5971                 ret = btrfs_update_inode(trans, root, inode);
5972         }
5973         btrfs_end_transaction(trans, root);
5974         if (BTRFS_I(inode)->delayed_node)
5975                 btrfs_balance_delayed_items(root);
5976
5977         return ret;
5978 }
5979
5980 /*
5981  * This is a copy of file_update_time.  We need this so we can return error on
5982  * ENOSPC for updating the inode in the case of file write and mmap writes.
5983  */
5984 static int btrfs_update_time(struct inode *inode, struct timespec *now,
5985                              int flags)
5986 {
5987         struct btrfs_root *root = BTRFS_I(inode)->root;
5988
5989         if (btrfs_root_readonly(root))
5990                 return -EROFS;
5991
5992         if (flags & S_VERSION)
5993                 inode_inc_iversion(inode);
5994         if (flags & S_CTIME)
5995                 inode->i_ctime = *now;
5996         if (flags & S_MTIME)
5997                 inode->i_mtime = *now;
5998         if (flags & S_ATIME)
5999                 inode->i_atime = *now;
6000         return btrfs_dirty_inode(inode);
6001 }
6002
6003 /*
6004  * find the highest existing sequence number in a directory
6005  * and then set the in-memory index_cnt variable to reflect
6006  * free sequence numbers
6007  */
6008 static int btrfs_set_inode_index_count(struct inode *inode)
6009 {
6010         struct btrfs_root *root = BTRFS_I(inode)->root;
6011         struct btrfs_key key, found_key;
6012         struct btrfs_path *path;
6013         struct extent_buffer *leaf;
6014         int ret;
6015
6016         key.objectid = btrfs_ino(inode);
6017         key.type = BTRFS_DIR_INDEX_KEY;
6018         key.offset = (u64)-1;
6019
6020         path = btrfs_alloc_path();
6021         if (!path)
6022                 return -ENOMEM;
6023
6024         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6025         if (ret < 0)
6026                 goto out;
6027         /* FIXME: we should be able to handle this */
6028         if (ret == 0)
6029                 goto out;
6030         ret = 0;
6031
6032         /*
6033          * MAGIC NUMBER EXPLANATION:
6034          * since we search a directory based on f_pos we have to start at 2
6035          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
6036          * else has to start at 2
6037          */
6038         if (path->slots[0] == 0) {
6039                 BTRFS_I(inode)->index_cnt = 2;
6040                 goto out;
6041         }
6042
6043         path->slots[0]--;
6044
6045         leaf = path->nodes[0];
6046         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6047
6048         if (found_key.objectid != btrfs_ino(inode) ||
6049             found_key.type != BTRFS_DIR_INDEX_KEY) {
6050                 BTRFS_I(inode)->index_cnt = 2;
6051                 goto out;
6052         }
6053
6054         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
6055 out:
6056         btrfs_free_path(path);
6057         return ret;
6058 }
6059
6060 /*
6061  * helper to find a free sequence number in a given directory.  This current
6062  * code is very simple, later versions will do smarter things in the btree
6063  */
6064 int btrfs_set_inode_index(struct inode *dir, u64 *index)
6065 {
6066         int ret = 0;
6067
6068         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
6069                 ret = btrfs_inode_delayed_dir_index_count(dir);
6070                 if (ret) {
6071                         ret = btrfs_set_inode_index_count(dir);
6072                         if (ret)
6073                                 return ret;
6074                 }
6075         }
6076
6077         *index = BTRFS_I(dir)->index_cnt;
6078         BTRFS_I(dir)->index_cnt++;
6079
6080         return ret;
6081 }
6082
6083 static int btrfs_insert_inode_locked(struct inode *inode)
6084 {
6085         struct btrfs_iget_args args;
6086         args.location = &BTRFS_I(inode)->location;
6087         args.root = BTRFS_I(inode)->root;
6088
6089         return insert_inode_locked4(inode,
6090                    btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root),
6091                    btrfs_find_actor, &args);
6092 }
6093
6094 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
6095                                      struct btrfs_root *root,
6096                                      struct inode *dir,
6097                                      const char *name, int name_len,
6098                                      u64 ref_objectid, u64 objectid,
6099                                      umode_t mode, u64 *index)
6100 {
6101         struct inode *inode;
6102         struct btrfs_inode_item *inode_item;
6103         struct btrfs_key *location;
6104         struct btrfs_path *path;
6105         struct btrfs_inode_ref *ref;
6106         struct btrfs_key key[2];
6107         u32 sizes[2];
6108         int nitems = name ? 2 : 1;
6109         unsigned long ptr;
6110         int ret;
6111
6112         path = btrfs_alloc_path();
6113         if (!path)
6114                 return ERR_PTR(-ENOMEM);
6115
6116         inode = new_inode(root->fs_info->sb);
6117         if (!inode) {
6118                 btrfs_free_path(path);
6119                 return ERR_PTR(-ENOMEM);
6120         }
6121
6122         /*
6123          * O_TMPFILE, set link count to 0, so that after this point,
6124          * we fill in an inode item with the correct link count.
6125          */
6126         if (!name)
6127                 set_nlink(inode, 0);
6128
6129         /*
6130          * we have to initialize this early, so we can reclaim the inode
6131          * number if we fail afterwards in this function.
6132          */
6133         inode->i_ino = objectid;
6134
6135         if (dir && name) {
6136                 trace_btrfs_inode_request(dir);
6137
6138                 ret = btrfs_set_inode_index(dir, index);
6139                 if (ret) {
6140                         btrfs_free_path(path);
6141                         iput(inode);
6142                         return ERR_PTR(ret);
6143                 }
6144         } else if (dir) {
6145                 *index = 0;
6146         }
6147         /*
6148          * index_cnt is ignored for everything but a dir,
6149          * btrfs_get_inode_index_count has an explanation for the magic
6150          * number
6151          */
6152         BTRFS_I(inode)->index_cnt = 2;
6153         BTRFS_I(inode)->dir_index = *index;
6154         BTRFS_I(inode)->root = root;
6155         BTRFS_I(inode)->generation = trans->transid;
6156         inode->i_generation = BTRFS_I(inode)->generation;
6157
6158         /*
6159          * We could have gotten an inode number from somebody who was fsynced
6160          * and then removed in this same transaction, so let's just set full
6161          * sync since it will be a full sync anyway and this will blow away the
6162          * old info in the log.
6163          */
6164         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
6165
6166         key[0].objectid = objectid;
6167         key[0].type = BTRFS_INODE_ITEM_KEY;
6168         key[0].offset = 0;
6169
6170         sizes[0] = sizeof(struct btrfs_inode_item);
6171
6172         if (name) {
6173                 /*
6174                  * Start new inodes with an inode_ref. This is slightly more
6175                  * efficient for small numbers of hard links since they will
6176                  * be packed into one item. Extended refs will kick in if we
6177                  * add more hard links than can fit in the ref item.
6178                  */
6179                 key[1].objectid = objectid;
6180                 key[1].type = BTRFS_INODE_REF_KEY;
6181                 key[1].offset = ref_objectid;
6182
6183                 sizes[1] = name_len + sizeof(*ref);
6184         }
6185
6186         location = &BTRFS_I(inode)->location;
6187         location->objectid = objectid;
6188         location->offset = 0;
6189         location->type = BTRFS_INODE_ITEM_KEY;
6190
6191         ret = btrfs_insert_inode_locked(inode);
6192         if (ret < 0)
6193                 goto fail;
6194
6195         path->leave_spinning = 1;
6196         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
6197         if (ret != 0)
6198                 goto fail_unlock;
6199
6200         inode_init_owner(inode, dir, mode);
6201         inode_set_bytes(inode, 0);
6202
6203         inode->i_mtime = CURRENT_TIME;
6204         inode->i_atime = inode->i_mtime;
6205         inode->i_ctime = inode->i_mtime;
6206         BTRFS_I(inode)->i_otime = inode->i_mtime;
6207
6208         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
6209                                   struct btrfs_inode_item);
6210         memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
6211                              sizeof(*inode_item));
6212         fill_inode_item(trans, path->nodes[0], inode_item, inode);
6213
6214         if (name) {
6215                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
6216                                      struct btrfs_inode_ref);
6217                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
6218                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
6219                 ptr = (unsigned long)(ref + 1);
6220                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
6221         }
6222
6223         btrfs_mark_buffer_dirty(path->nodes[0]);
6224         btrfs_free_path(path);
6225
6226         btrfs_inherit_iflags(inode, dir);
6227
6228         if (S_ISREG(mode)) {
6229                 if (btrfs_test_opt(root, NODATASUM))
6230                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
6231                 if (btrfs_test_opt(root, NODATACOW))
6232                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
6233                                 BTRFS_INODE_NODATASUM;
6234         }
6235
6236         inode_tree_add(inode);
6237
6238         trace_btrfs_inode_new(inode);
6239         btrfs_set_inode_last_trans(trans, inode);
6240
6241         btrfs_update_root_times(trans, root);
6242
6243         ret = btrfs_inode_inherit_props(trans, inode, dir);
6244         if (ret)
6245                 btrfs_err(root->fs_info,
6246                           "error inheriting props for ino %llu (root %llu): %d",
6247                           btrfs_ino(inode), root->root_key.objectid, ret);
6248
6249         return inode;
6250
6251 fail_unlock:
6252         unlock_new_inode(inode);
6253 fail:
6254         if (dir && name)
6255                 BTRFS_I(dir)->index_cnt--;
6256         btrfs_free_path(path);
6257         iput(inode);
6258         return ERR_PTR(ret);
6259 }
6260
6261 static inline u8 btrfs_inode_type(struct inode *inode)
6262 {
6263         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
6264 }
6265
6266 /*
6267  * utility function to add 'inode' into 'parent_inode' with
6268  * a give name and a given sequence number.
6269  * if 'add_backref' is true, also insert a backref from the
6270  * inode to the parent directory.
6271  */
6272 int btrfs_add_link(struct btrfs_trans_handle *trans,
6273                    struct inode *parent_inode, struct inode *inode,
6274                    const char *name, int name_len, int add_backref, u64 index)
6275 {
6276         int ret = 0;
6277         struct btrfs_key key;
6278         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
6279         u64 ino = btrfs_ino(inode);
6280         u64 parent_ino = btrfs_ino(parent_inode);
6281
6282         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6283                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
6284         } else {
6285                 key.objectid = ino;
6286                 key.type = BTRFS_INODE_ITEM_KEY;
6287                 key.offset = 0;
6288         }
6289
6290         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6291                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
6292                                          key.objectid, root->root_key.objectid,
6293                                          parent_ino, index, name, name_len);
6294         } else if (add_backref) {
6295                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
6296                                              parent_ino, index);
6297         }
6298
6299         /* Nothing to clean up yet */
6300         if (ret)
6301                 return ret;
6302
6303         ret = btrfs_insert_dir_item(trans, root, name, name_len,
6304                                     parent_inode, &key,
6305                                     btrfs_inode_type(inode), index);
6306         if (ret == -EEXIST || ret == -EOVERFLOW)
6307                 goto fail_dir_item;
6308         else if (ret) {
6309                 btrfs_abort_transaction(trans, root, ret);
6310                 return ret;
6311         }
6312
6313         btrfs_i_size_write(parent_inode, parent_inode->i_size +
6314                            name_len * 2);
6315         inode_inc_iversion(parent_inode);
6316         parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
6317         ret = btrfs_update_inode(trans, root, parent_inode);
6318         if (ret)
6319                 btrfs_abort_transaction(trans, root, ret);
6320         return ret;
6321
6322 fail_dir_item:
6323         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6324                 u64 local_index;
6325                 int err;
6326                 err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
6327                                  key.objectid, root->root_key.objectid,
6328                                  parent_ino, &local_index, name, name_len);
6329
6330         } else if (add_backref) {
6331                 u64 local_index;
6332                 int err;
6333
6334                 err = btrfs_del_inode_ref(trans, root, name, name_len,
6335                                           ino, parent_ino, &local_index);
6336         }
6337         return ret;
6338 }
6339
6340 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
6341                             struct inode *dir, struct dentry *dentry,
6342                             struct inode *inode, int backref, u64 index)
6343 {
6344         int err = btrfs_add_link(trans, dir, inode,
6345                                  dentry->d_name.name, dentry->d_name.len,
6346                                  backref, index);
6347         if (err > 0)
6348                 err = -EEXIST;
6349         return err;
6350 }
6351
6352 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
6353                         umode_t mode, dev_t rdev)
6354 {
6355         struct btrfs_trans_handle *trans;
6356         struct btrfs_root *root = BTRFS_I(dir)->root;
6357         struct inode *inode = NULL;
6358         int err;
6359         int drop_inode = 0;
6360         u64 objectid;
6361         u64 index = 0;
6362
6363         if (!new_valid_dev(rdev))
6364                 return -EINVAL;
6365
6366         /*
6367          * 2 for inode item and ref
6368          * 2 for dir items
6369          * 1 for xattr if selinux is on
6370          */
6371         trans = btrfs_start_transaction(root, 5);
6372         if (IS_ERR(trans))
6373                 return PTR_ERR(trans);
6374
6375         err = btrfs_find_free_ino(root, &objectid);
6376         if (err)
6377                 goto out_unlock;
6378
6379         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6380                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6381                                 mode, &index);
6382         if (IS_ERR(inode)) {
6383                 err = PTR_ERR(inode);
6384                 goto out_unlock;
6385         }
6386
6387         /*
6388         * If the active LSM wants to access the inode during
6389         * d_instantiate it needs these. Smack checks to see
6390         * if the filesystem supports xattrs by looking at the
6391         * ops vector.
6392         */
6393         inode->i_op = &btrfs_special_inode_operations;
6394         init_special_inode(inode, inode->i_mode, rdev);
6395
6396         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6397         if (err)
6398                 goto out_unlock_inode;
6399
6400         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6401         if (err) {
6402                 goto out_unlock_inode;
6403         } else {
6404                 btrfs_update_inode(trans, root, inode);
6405                 unlock_new_inode(inode);
6406                 d_instantiate(dentry, inode);
6407         }
6408
6409 out_unlock:
6410         btrfs_end_transaction(trans, root);
6411         btrfs_balance_delayed_items(root);
6412         btrfs_btree_balance_dirty(root);
6413         if (drop_inode) {
6414                 inode_dec_link_count(inode);
6415                 iput(inode);
6416         }
6417         return err;
6418
6419 out_unlock_inode:
6420         drop_inode = 1;
6421         unlock_new_inode(inode);
6422         goto out_unlock;
6423
6424 }
6425
6426 static int btrfs_create(struct inode *dir, struct dentry *dentry,
6427                         umode_t mode, bool excl)
6428 {
6429         struct btrfs_trans_handle *trans;
6430         struct btrfs_root *root = BTRFS_I(dir)->root;
6431         struct inode *inode = NULL;
6432         int drop_inode_on_err = 0;
6433         int err;
6434         u64 objectid;
6435         u64 index = 0;
6436
6437         /*
6438          * 2 for inode item and ref
6439          * 2 for dir items
6440          * 1 for xattr if selinux is on
6441          */
6442         trans = btrfs_start_transaction(root, 5);
6443         if (IS_ERR(trans))
6444                 return PTR_ERR(trans);
6445
6446         err = btrfs_find_free_ino(root, &objectid);
6447         if (err)
6448                 goto out_unlock;
6449
6450         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6451                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6452                                 mode, &index);
6453         if (IS_ERR(inode)) {
6454                 err = PTR_ERR(inode);
6455                 goto out_unlock;
6456         }
6457         drop_inode_on_err = 1;
6458         /*
6459         * If the active LSM wants to access the inode during
6460         * d_instantiate it needs these. Smack checks to see
6461         * if the filesystem supports xattrs by looking at the
6462         * ops vector.
6463         */
6464         inode->i_fop = &btrfs_file_operations;
6465         inode->i_op = &btrfs_file_inode_operations;
6466         inode->i_mapping->a_ops = &btrfs_aops;
6467
6468         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6469         if (err)
6470                 goto out_unlock_inode;
6471
6472         err = btrfs_update_inode(trans, root, inode);
6473         if (err)
6474                 goto out_unlock_inode;
6475
6476         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6477         if (err)
6478                 goto out_unlock_inode;
6479
6480         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
6481         unlock_new_inode(inode);
6482         d_instantiate(dentry, inode);
6483
6484 out_unlock:
6485         btrfs_end_transaction(trans, root);
6486         if (err && drop_inode_on_err) {
6487                 inode_dec_link_count(inode);
6488                 iput(inode);
6489         }
6490         btrfs_balance_delayed_items(root);
6491         btrfs_btree_balance_dirty(root);
6492         return err;
6493
6494 out_unlock_inode:
6495         unlock_new_inode(inode);
6496         goto out_unlock;
6497
6498 }
6499
6500 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
6501                       struct dentry *dentry)
6502 {
6503         struct btrfs_trans_handle *trans;
6504         struct btrfs_root *root = BTRFS_I(dir)->root;
6505         struct inode *inode = d_inode(old_dentry);
6506         u64 index;
6507         int err;
6508         int drop_inode = 0;
6509
6510         /* do not allow sys_link's with other subvols of the same device */
6511         if (root->objectid != BTRFS_I(inode)->root->objectid)
6512                 return -EXDEV;
6513
6514         if (inode->i_nlink >= BTRFS_LINK_MAX)
6515                 return -EMLINK;
6516
6517         err = btrfs_set_inode_index(dir, &index);
6518         if (err)
6519                 goto fail;
6520
6521         /*
6522          * 2 items for inode and inode ref
6523          * 2 items for dir items
6524          * 1 item for parent inode
6525          */
6526         trans = btrfs_start_transaction(root, 5);
6527         if (IS_ERR(trans)) {
6528                 err = PTR_ERR(trans);
6529                 goto fail;
6530         }
6531
6532         /* There are several dir indexes for this inode, clear the cache. */
6533         BTRFS_I(inode)->dir_index = 0ULL;
6534         inc_nlink(inode);
6535         inode_inc_iversion(inode);
6536         inode->i_ctime = CURRENT_TIME;
6537         ihold(inode);
6538         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
6539
6540         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
6541
6542         if (err) {
6543                 drop_inode = 1;
6544         } else {
6545                 struct dentry *parent = dentry->d_parent;
6546                 err = btrfs_update_inode(trans, root, inode);
6547                 if (err)
6548                         goto fail;
6549                 if (inode->i_nlink == 1) {
6550                         /*
6551                          * If new hard link count is 1, it's a file created
6552                          * with open(2) O_TMPFILE flag.
6553                          */
6554                         err = btrfs_orphan_del(trans, inode);
6555                         if (err)
6556                                 goto fail;
6557                 }
6558                 d_instantiate(dentry, inode);
6559                 btrfs_log_new_name(trans, inode, NULL, parent);
6560         }
6561
6562         btrfs_end_transaction(trans, root);
6563         btrfs_balance_delayed_items(root);
6564 fail:
6565         if (drop_inode) {
6566                 inode_dec_link_count(inode);
6567                 iput(inode);
6568         }
6569         btrfs_btree_balance_dirty(root);
6570         return err;
6571 }
6572
6573 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6574 {
6575         struct inode *inode = NULL;
6576         struct btrfs_trans_handle *trans;
6577         struct btrfs_root *root = BTRFS_I(dir)->root;
6578         int err = 0;
6579         int drop_on_err = 0;
6580         u64 objectid = 0;
6581         u64 index = 0;
6582
6583         /*
6584          * 2 items for inode and ref
6585          * 2 items for dir items
6586          * 1 for xattr if selinux is on
6587          */
6588         trans = btrfs_start_transaction(root, 5);
6589         if (IS_ERR(trans))
6590                 return PTR_ERR(trans);
6591
6592         err = btrfs_find_free_ino(root, &objectid);
6593         if (err)
6594                 goto out_fail;
6595
6596         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6597                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6598                                 S_IFDIR | mode, &index);
6599         if (IS_ERR(inode)) {
6600                 err = PTR_ERR(inode);
6601                 goto out_fail;
6602         }
6603
6604         drop_on_err = 1;
6605         /* these must be set before we unlock the inode */
6606         inode->i_op = &btrfs_dir_inode_operations;
6607         inode->i_fop = &btrfs_dir_file_operations;
6608
6609         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6610         if (err)
6611                 goto out_fail_inode;
6612
6613         btrfs_i_size_write(inode, 0);
6614         err = btrfs_update_inode(trans, root, inode);
6615         if (err)
6616                 goto out_fail_inode;
6617
6618         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
6619                              dentry->d_name.len, 0, index);
6620         if (err)
6621                 goto out_fail_inode;
6622
6623         d_instantiate(dentry, inode);
6624         /*
6625          * mkdir is special.  We're unlocking after we call d_instantiate
6626          * to avoid a race with nfsd calling d_instantiate.
6627          */
6628         unlock_new_inode(inode);
6629         drop_on_err = 0;
6630
6631 out_fail:
6632         btrfs_end_transaction(trans, root);
6633         if (drop_on_err) {
6634                 inode_dec_link_count(inode);
6635                 iput(inode);
6636         }
6637         btrfs_balance_delayed_items(root);
6638         btrfs_btree_balance_dirty(root);
6639         return err;
6640
6641 out_fail_inode:
6642         unlock_new_inode(inode);
6643         goto out_fail;
6644 }
6645
6646 /* Find next extent map of a given extent map, caller needs to ensure locks */
6647 static struct extent_map *next_extent_map(struct extent_map *em)
6648 {
6649         struct rb_node *next;
6650
6651         next = rb_next(&em->rb_node);
6652         if (!next)
6653                 return NULL;
6654         return container_of(next, struct extent_map, rb_node);
6655 }
6656
6657 static struct extent_map *prev_extent_map(struct extent_map *em)
6658 {
6659         struct rb_node *prev;
6660
6661         prev = rb_prev(&em->rb_node);
6662         if (!prev)
6663                 return NULL;
6664         return container_of(prev, struct extent_map, rb_node);
6665 }
6666
6667 /* helper for btfs_get_extent.  Given an existing extent in the tree,
6668  * the existing extent is the nearest extent to map_start,
6669  * and an extent that you want to insert, deal with overlap and insert
6670  * the best fitted new extent into the tree.
6671  */
6672 static int merge_extent_mapping(struct extent_map_tree *em_tree,
6673                                 struct extent_map *existing,
6674                                 struct extent_map *em,
6675                                 u64 map_start)
6676 {
6677         struct extent_map *prev;
6678         struct extent_map *next;
6679         u64 start;
6680         u64 end;
6681         u64 start_diff;
6682
6683         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
6684
6685         if (existing->start > map_start) {
6686                 next = existing;
6687                 prev = prev_extent_map(next);
6688         } else {
6689                 prev = existing;
6690                 next = next_extent_map(prev);
6691         }
6692
6693         start = prev ? extent_map_end(prev) : em->start;
6694         start = max_t(u64, start, em->start);
6695         end = next ? next->start : extent_map_end(em);
6696         end = min_t(u64, end, extent_map_end(em));
6697         start_diff = start - em->start;
6698         em->start = start;
6699         em->len = end - start;
6700         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
6701             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
6702                 em->block_start += start_diff;
6703                 em->block_len -= start_diff;
6704         }
6705         return add_extent_mapping(em_tree, em, 0);
6706 }
6707
6708 static noinline int uncompress_inline(struct btrfs_path *path,
6709                                       struct inode *inode, struct page *page,
6710                                       size_t pg_offset, u64 extent_offset,
6711                                       struct btrfs_file_extent_item *item)
6712 {
6713         int ret;
6714         struct extent_buffer *leaf = path->nodes[0];
6715         char *tmp;
6716         size_t max_size;
6717         unsigned long inline_size;
6718         unsigned long ptr;
6719         int compress_type;
6720
6721         WARN_ON(pg_offset != 0);
6722         compress_type = btrfs_file_extent_compression(leaf, item);
6723         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6724         inline_size = btrfs_file_extent_inline_item_len(leaf,
6725                                         btrfs_item_nr(path->slots[0]));
6726         tmp = kmalloc(inline_size, GFP_NOFS);
6727         if (!tmp)
6728                 return -ENOMEM;
6729         ptr = btrfs_file_extent_inline_start(item);
6730
6731         read_extent_buffer(leaf, tmp, ptr, inline_size);
6732
6733         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
6734         ret = btrfs_decompress(compress_type, tmp, page,
6735                                extent_offset, inline_size, max_size);
6736         kfree(tmp);
6737         return ret;
6738 }
6739
6740 /*
6741  * a bit scary, this does extent mapping from logical file offset to the disk.
6742  * the ugly parts come from merging extents from the disk with the in-ram
6743  * representation.  This gets more complex because of the data=ordered code,
6744  * where the in-ram extents might be locked pending data=ordered completion.
6745  *
6746  * This also copies inline extents directly into the page.
6747  */
6748
6749 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
6750                                     size_t pg_offset, u64 start, u64 len,
6751                                     int create)
6752 {
6753         int ret;
6754         int err = 0;
6755         u64 extent_start = 0;
6756         u64 extent_end = 0;
6757         u64 objectid = btrfs_ino(inode);
6758         u32 found_type;
6759         struct btrfs_path *path = NULL;
6760         struct btrfs_root *root = BTRFS_I(inode)->root;
6761         struct btrfs_file_extent_item *item;
6762         struct extent_buffer *leaf;
6763         struct btrfs_key found_key;
6764         struct extent_map *em = NULL;
6765         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
6766         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6767         struct btrfs_trans_handle *trans = NULL;
6768         const bool new_inline = !page || create;
6769
6770 again:
6771         read_lock(&em_tree->lock);
6772         em = lookup_extent_mapping(em_tree, start, len);
6773         if (em)
6774                 em->bdev = root->fs_info->fs_devices->latest_bdev;
6775         read_unlock(&em_tree->lock);
6776
6777         if (em) {
6778                 if (em->start > start || em->start + em->len <= start)
6779                         free_extent_map(em);
6780                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6781                         free_extent_map(em);
6782                 else
6783                         goto out;
6784         }
6785         em = alloc_extent_map();
6786         if (!em) {
6787                 err = -ENOMEM;
6788                 goto out;
6789         }
6790         em->bdev = root->fs_info->fs_devices->latest_bdev;
6791         em->start = EXTENT_MAP_HOLE;
6792         em->orig_start = EXTENT_MAP_HOLE;
6793         em->len = (u64)-1;
6794         em->block_len = (u64)-1;
6795
6796         if (!path) {
6797                 path = btrfs_alloc_path();
6798                 if (!path) {
6799                         err = -ENOMEM;
6800                         goto out;
6801                 }
6802                 /*
6803                  * Chances are we'll be called again, so go ahead and do
6804                  * readahead
6805                  */
6806                 path->reada = 1;
6807         }
6808
6809         ret = btrfs_lookup_file_extent(trans, root, path,
6810                                        objectid, start, trans != NULL);
6811         if (ret < 0) {
6812                 err = ret;
6813                 goto out;
6814         }
6815
6816         if (ret != 0) {
6817                 if (path->slots[0] == 0)
6818                         goto not_found;
6819                 path->slots[0]--;
6820         }
6821
6822         leaf = path->nodes[0];
6823         item = btrfs_item_ptr(leaf, path->slots[0],
6824                               struct btrfs_file_extent_item);
6825         /* are we inside the extent that was found? */
6826         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6827         found_type = found_key.type;
6828         if (found_key.objectid != objectid ||
6829             found_type != BTRFS_EXTENT_DATA_KEY) {
6830                 /*
6831                  * If we backup past the first extent we want to move forward
6832                  * and see if there is an extent in front of us, otherwise we'll
6833                  * say there is a hole for our whole search range which can
6834                  * cause problems.
6835                  */
6836                 extent_end = start;
6837                 goto next;
6838         }
6839
6840         found_type = btrfs_file_extent_type(leaf, item);
6841         extent_start = found_key.offset;
6842         if (found_type == BTRFS_FILE_EXTENT_REG ||
6843             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6844                 extent_end = extent_start +
6845                        btrfs_file_extent_num_bytes(leaf, item);
6846         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6847                 size_t size;
6848                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6849                 extent_end = ALIGN(extent_start + size, root->sectorsize);
6850         }
6851 next:
6852         if (start >= extent_end) {
6853                 path->slots[0]++;
6854                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6855                         ret = btrfs_next_leaf(root, path);
6856                         if (ret < 0) {
6857                                 err = ret;
6858                                 goto out;
6859                         }
6860                         if (ret > 0)
6861                                 goto not_found;
6862                         leaf = path->nodes[0];
6863                 }
6864                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6865                 if (found_key.objectid != objectid ||
6866                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6867                         goto not_found;
6868                 if (start + len <= found_key.offset)
6869                         goto not_found;
6870                 if (start > found_key.offset)
6871                         goto next;
6872                 em->start = start;
6873                 em->orig_start = start;
6874                 em->len = found_key.offset - start;
6875                 goto not_found_em;
6876         }
6877
6878         btrfs_extent_item_to_extent_map(inode, path, item, new_inline, em);
6879
6880         if (found_type == BTRFS_FILE_EXTENT_REG ||
6881             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6882                 goto insert;
6883         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6884                 unsigned long ptr;
6885                 char *map;
6886                 size_t size;
6887                 size_t extent_offset;
6888                 size_t copy_size;
6889
6890                 if (new_inline)
6891                         goto out;
6892
6893                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6894                 extent_offset = page_offset(page) + pg_offset - extent_start;
6895                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
6896                                 size - extent_offset);
6897                 em->start = extent_start + extent_offset;
6898                 em->len = ALIGN(copy_size, root->sectorsize);
6899                 em->orig_block_len = em->len;
6900                 em->orig_start = em->start;
6901                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6902                 if (create == 0 && !PageUptodate(page)) {
6903                         if (btrfs_file_extent_compression(leaf, item) !=
6904                             BTRFS_COMPRESS_NONE) {
6905                                 ret = uncompress_inline(path, inode, page,
6906                                                         pg_offset,
6907                                                         extent_offset, item);
6908                                 if (ret) {
6909                                         err = ret;
6910                                         goto out;
6911                                 }
6912                         } else {
6913                                 map = kmap(page);
6914                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6915                                                    copy_size);
6916                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
6917                                         memset(map + pg_offset + copy_size, 0,
6918                                                PAGE_CACHE_SIZE - pg_offset -
6919                                                copy_size);
6920                                 }
6921                                 kunmap(page);
6922                         }
6923                         flush_dcache_page(page);
6924                 } else if (create && PageUptodate(page)) {
6925                         BUG();
6926                         if (!trans) {
6927                                 kunmap(page);
6928                                 free_extent_map(em);
6929                                 em = NULL;
6930
6931                                 btrfs_release_path(path);
6932                                 trans = btrfs_join_transaction(root);
6933
6934                                 if (IS_ERR(trans))
6935                                         return ERR_CAST(trans);
6936                                 goto again;
6937                         }
6938                         map = kmap(page);
6939                         write_extent_buffer(leaf, map + pg_offset, ptr,
6940                                             copy_size);
6941                         kunmap(page);
6942                         btrfs_mark_buffer_dirty(leaf);
6943                 }
6944                 set_extent_uptodate(io_tree, em->start,
6945                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6946                 goto insert;
6947         }
6948 not_found:
6949         em->start = start;
6950         em->orig_start = start;
6951         em->len = len;
6952 not_found_em:
6953         em->block_start = EXTENT_MAP_HOLE;
6954         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
6955 insert:
6956         btrfs_release_path(path);
6957         if (em->start > start || extent_map_end(em) <= start) {
6958                 btrfs_err(root->fs_info, "bad extent! em: [%llu %llu] passed [%llu %llu]",
6959                         em->start, em->len, start, len);
6960                 err = -EIO;
6961                 goto out;
6962         }
6963
6964         err = 0;
6965         write_lock(&em_tree->lock);
6966         ret = add_extent_mapping(em_tree, em, 0);
6967         /* it is possible that someone inserted the extent into the tree
6968          * while we had the lock dropped.  It is also possible that
6969          * an overlapping map exists in the tree
6970          */
6971         if (ret == -EEXIST) {
6972                 struct extent_map *existing;
6973
6974                 ret = 0;
6975
6976                 existing = search_extent_mapping(em_tree, start, len);
6977                 /*
6978                  * existing will always be non-NULL, since there must be
6979                  * extent causing the -EEXIST.
6980                  */
6981                 if (start >= extent_map_end(existing) ||
6982                     start <= existing->start) {
6983                         /*
6984                          * The existing extent map is the one nearest to
6985                          * the [start, start + len) range which overlaps
6986                          */
6987                         err = merge_extent_mapping(em_tree, existing,
6988                                                    em, start);
6989                         free_extent_map(existing);
6990                         if (err) {
6991                                 free_extent_map(em);
6992                                 em = NULL;
6993                         }
6994                 } else {
6995                         free_extent_map(em);
6996                         em = existing;
6997                         err = 0;
6998                 }
6999         }
7000         write_unlock(&em_tree->lock);
7001 out:
7002
7003         trace_btrfs_get_extent(root, em);
7004
7005         btrfs_free_path(path);
7006         if (trans) {
7007                 ret = btrfs_end_transaction(trans, root);
7008                 if (!err)
7009                         err = ret;
7010         }
7011         if (err) {
7012                 free_extent_map(em);
7013                 return ERR_PTR(err);
7014         }
7015         BUG_ON(!em); /* Error is always set */
7016         return em;
7017 }
7018
7019 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
7020                                            size_t pg_offset, u64 start, u64 len,
7021                                            int create)
7022 {
7023         struct extent_map *em;
7024         struct extent_map *hole_em = NULL;
7025         u64 range_start = start;
7026         u64 end;
7027         u64 found;
7028         u64 found_end;
7029         int err = 0;
7030
7031         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
7032         if (IS_ERR(em))
7033                 return em;
7034         if (em) {
7035                 /*
7036                  * if our em maps to
7037                  * -  a hole or
7038                  * -  a pre-alloc extent,
7039                  * there might actually be delalloc bytes behind it.
7040                  */
7041                 if (em->block_start != EXTENT_MAP_HOLE &&
7042                     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7043                         return em;
7044                 else
7045                         hole_em = em;
7046         }
7047
7048         /* check to see if we've wrapped (len == -1 or similar) */
7049         end = start + len;
7050         if (end < start)
7051                 end = (u64)-1;
7052         else
7053                 end -= 1;
7054
7055         em = NULL;
7056
7057         /* ok, we didn't find anything, lets look for delalloc */
7058         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
7059                                  end, len, EXTENT_DELALLOC, 1);
7060         found_end = range_start + found;
7061         if (found_end < range_start)
7062                 found_end = (u64)-1;
7063
7064         /*
7065          * we didn't find anything useful, return
7066          * the original results from get_extent()
7067          */
7068         if (range_start > end || found_end <= start) {
7069                 em = hole_em;
7070                 hole_em = NULL;
7071                 goto out;
7072         }
7073
7074         /* adjust the range_start to make sure it doesn't
7075          * go backwards from the start they passed in
7076          */
7077         range_start = max(start, range_start);
7078         found = found_end - range_start;
7079
7080         if (found > 0) {
7081                 u64 hole_start = start;
7082                 u64 hole_len = len;
7083
7084                 em = alloc_extent_map();
7085                 if (!em) {
7086                         err = -ENOMEM;
7087                         goto out;
7088                 }
7089                 /*
7090                  * when btrfs_get_extent can't find anything it
7091                  * returns one huge hole
7092                  *
7093                  * make sure what it found really fits our range, and
7094                  * adjust to make sure it is based on the start from
7095                  * the caller
7096                  */
7097                 if (hole_em) {
7098                         u64 calc_end = extent_map_end(hole_em);
7099
7100                         if (calc_end <= start || (hole_em->start > end)) {
7101                                 free_extent_map(hole_em);
7102                                 hole_em = NULL;
7103                         } else {
7104                                 hole_start = max(hole_em->start, start);
7105                                 hole_len = calc_end - hole_start;
7106                         }
7107                 }
7108                 em->bdev = NULL;
7109                 if (hole_em && range_start > hole_start) {
7110                         /* our hole starts before our delalloc, so we
7111                          * have to return just the parts of the hole
7112                          * that go until  the delalloc starts
7113                          */
7114                         em->len = min(hole_len,
7115                                       range_start - hole_start);
7116                         em->start = hole_start;
7117                         em->orig_start = hole_start;
7118                         /*
7119                          * don't adjust block start at all,
7120                          * it is fixed at EXTENT_MAP_HOLE
7121                          */
7122                         em->block_start = hole_em->block_start;
7123                         em->block_len = hole_len;
7124                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
7125                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
7126                 } else {
7127                         em->start = range_start;
7128                         em->len = found;
7129                         em->orig_start = range_start;
7130                         em->block_start = EXTENT_MAP_DELALLOC;
7131                         em->block_len = found;
7132                 }
7133         } else if (hole_em) {
7134                 return hole_em;
7135         }
7136 out:
7137
7138         free_extent_map(hole_em);
7139         if (err) {
7140                 free_extent_map(em);
7141                 return ERR_PTR(err);
7142         }
7143         return em;
7144 }
7145
7146 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
7147                                                   u64 start, u64 len)
7148 {
7149         struct btrfs_root *root = BTRFS_I(inode)->root;
7150         struct extent_map *em;
7151         struct btrfs_key ins;
7152         u64 alloc_hint;
7153         int ret;
7154
7155         alloc_hint = get_extent_allocation_hint(inode, start, len);
7156         ret = btrfs_reserve_extent(root, len, root->sectorsize, 0,
7157                                    alloc_hint, &ins, 1, 1);
7158         if (ret)
7159                 return ERR_PTR(ret);
7160
7161         em = create_pinned_em(inode, start, ins.offset, start, ins.objectid,
7162                               ins.offset, ins.offset, ins.offset, 0);
7163         if (IS_ERR(em)) {
7164                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
7165                 return em;
7166         }
7167
7168         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
7169                                            ins.offset, ins.offset, 0);
7170         if (ret) {
7171                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
7172                 free_extent_map(em);
7173                 return ERR_PTR(ret);
7174         }
7175
7176         return em;
7177 }
7178
7179 /*
7180  * returns 1 when the nocow is safe, < 1 on error, 0 if the
7181  * block must be cow'd
7182  */
7183 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
7184                               u64 *orig_start, u64 *orig_block_len,
7185                               u64 *ram_bytes)
7186 {
7187         struct btrfs_trans_handle *trans;
7188         struct btrfs_path *path;
7189         int ret;
7190         struct extent_buffer *leaf;
7191         struct btrfs_root *root = BTRFS_I(inode)->root;
7192         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7193         struct btrfs_file_extent_item *fi;
7194         struct btrfs_key key;
7195         u64 disk_bytenr;
7196         u64 backref_offset;
7197         u64 extent_end;
7198         u64 num_bytes;
7199         int slot;
7200         int found_type;
7201         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
7202
7203         path = btrfs_alloc_path();
7204         if (!path)
7205                 return -ENOMEM;
7206
7207         ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode),
7208                                        offset, 0);
7209         if (ret < 0)
7210                 goto out;
7211
7212         slot = path->slots[0];
7213         if (ret == 1) {
7214                 if (slot == 0) {
7215                         /* can't find the item, must cow */
7216                         ret = 0;
7217                         goto out;
7218                 }
7219                 slot--;
7220         }
7221         ret = 0;
7222         leaf = path->nodes[0];
7223         btrfs_item_key_to_cpu(leaf, &key, slot);
7224         if (key.objectid != btrfs_ino(inode) ||
7225             key.type != BTRFS_EXTENT_DATA_KEY) {
7226                 /* not our file or wrong item type, must cow */
7227                 goto out;
7228         }
7229
7230         if (key.offset > offset) {
7231                 /* Wrong offset, must cow */
7232                 goto out;
7233         }
7234
7235         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
7236         found_type = btrfs_file_extent_type(leaf, fi);
7237         if (found_type != BTRFS_FILE_EXTENT_REG &&
7238             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
7239                 /* not a regular extent, must cow */
7240                 goto out;
7241         }
7242
7243         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
7244                 goto out;
7245
7246         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
7247         if (extent_end <= offset)
7248                 goto out;
7249
7250         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
7251         if (disk_bytenr == 0)
7252                 goto out;
7253
7254         if (btrfs_file_extent_compression(leaf, fi) ||
7255             btrfs_file_extent_encryption(leaf, fi) ||
7256             btrfs_file_extent_other_encoding(leaf, fi))
7257                 goto out;
7258
7259         backref_offset = btrfs_file_extent_offset(leaf, fi);
7260
7261         if (orig_start) {
7262                 *orig_start = key.offset - backref_offset;
7263                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
7264                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
7265         }
7266
7267         if (btrfs_extent_readonly(root, disk_bytenr))
7268                 goto out;
7269
7270         num_bytes = min(offset + *len, extent_end) - offset;
7271         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
7272                 u64 range_end;
7273
7274                 range_end = round_up(offset + num_bytes, root->sectorsize) - 1;
7275                 ret = test_range_bit(io_tree, offset, range_end,
7276                                      EXTENT_DELALLOC, 0, NULL);
7277                 if (ret) {
7278                         ret = -EAGAIN;
7279                         goto out;
7280                 }
7281         }
7282
7283         btrfs_release_path(path);
7284
7285         /*
7286          * look for other files referencing this extent, if we
7287          * find any we must cow
7288          */
7289         trans = btrfs_join_transaction(root);
7290         if (IS_ERR(trans)) {
7291                 ret = 0;
7292                 goto out;
7293         }
7294
7295         ret = btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
7296                                     key.offset - backref_offset, disk_bytenr);
7297         btrfs_end_transaction(trans, root);
7298         if (ret) {
7299                 ret = 0;
7300                 goto out;
7301         }
7302
7303         /*
7304          * adjust disk_bytenr and num_bytes to cover just the bytes
7305          * in this extent we are about to write.  If there
7306          * are any csums in that range we have to cow in order
7307          * to keep the csums correct
7308          */
7309         disk_bytenr += backref_offset;
7310         disk_bytenr += offset - key.offset;
7311         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
7312                                 goto out;
7313         /*
7314          * all of the above have passed, it is safe to overwrite this extent
7315          * without cow
7316          */
7317         *len = num_bytes;
7318         ret = 1;
7319 out:
7320         btrfs_free_path(path);
7321         return ret;
7322 }
7323
7324 bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end)
7325 {
7326         struct radix_tree_root *root = &inode->i_mapping->page_tree;
7327         int found = false;
7328         void **pagep = NULL;
7329         struct page *page = NULL;
7330         int start_idx;
7331         int end_idx;
7332
7333         start_idx = start >> PAGE_CACHE_SHIFT;
7334
7335         /*
7336          * end is the last byte in the last page.  end == start is legal
7337          */
7338         end_idx = end >> PAGE_CACHE_SHIFT;
7339
7340         rcu_read_lock();
7341
7342         /* Most of the code in this while loop is lifted from
7343          * find_get_page.  It's been modified to begin searching from a
7344          * page and return just the first page found in that range.  If the
7345          * found idx is less than or equal to the end idx then we know that
7346          * a page exists.  If no pages are found or if those pages are
7347          * outside of the range then we're fine (yay!) */
7348         while (page == NULL &&
7349                radix_tree_gang_lookup_slot(root, &pagep, NULL, start_idx, 1)) {
7350                 page = radix_tree_deref_slot(pagep);
7351                 if (unlikely(!page))
7352                         break;
7353
7354                 if (radix_tree_exception(page)) {
7355                         if (radix_tree_deref_retry(page)) {
7356                                 page = NULL;
7357                                 continue;
7358                         }
7359                         /*
7360                          * Otherwise, shmem/tmpfs must be storing a swap entry
7361                          * here as an exceptional entry: so return it without
7362                          * attempting to raise page count.
7363                          */
7364                         page = NULL;
7365                         break; /* TODO: Is this relevant for this use case? */
7366                 }
7367
7368                 if (!page_cache_get_speculative(page)) {
7369                         page = NULL;
7370                         continue;
7371                 }
7372
7373                 /*
7374                  * Has the page moved?
7375                  * This is part of the lockless pagecache protocol. See
7376                  * include/linux/pagemap.h for details.
7377                  */
7378                 if (unlikely(page != *pagep)) {
7379                         page_cache_release(page);
7380                         page = NULL;
7381                 }
7382         }
7383
7384         if (page) {
7385                 if (page->index <= end_idx)
7386                         found = true;
7387                 page_cache_release(page);
7388         }
7389
7390         rcu_read_unlock();
7391         return found;
7392 }
7393
7394 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
7395                               struct extent_state **cached_state, int writing)
7396 {
7397         struct btrfs_ordered_extent *ordered;
7398         int ret = 0;
7399
7400         while (1) {
7401                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7402                                  0, cached_state);
7403                 /*
7404                  * We're concerned with the entire range that we're going to be
7405                  * doing DIO to, so we need to make sure theres no ordered
7406                  * extents in this range.
7407                  */
7408                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
7409                                                      lockend - lockstart + 1);
7410
7411                 /*
7412                  * We need to make sure there are no buffered pages in this
7413                  * range either, we could have raced between the invalidate in
7414                  * generic_file_direct_write and locking the extent.  The
7415                  * invalidate needs to happen so that reads after a write do not
7416                  * get stale data.
7417                  */
7418                 if (!ordered &&
7419                     (!writing ||
7420                      !btrfs_page_exists_in_range(inode, lockstart, lockend)))
7421                         break;
7422
7423                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7424                                      cached_state, GFP_NOFS);
7425
7426                 if (ordered) {
7427                         btrfs_start_ordered_extent(inode, ordered, 1);
7428                         btrfs_put_ordered_extent(ordered);
7429                 } else {
7430                         /* Screw you mmap */
7431                         ret = btrfs_fdatawrite_range(inode, lockstart, lockend);
7432                         if (ret)
7433                                 break;
7434                         ret = filemap_fdatawait_range(inode->i_mapping,
7435                                                       lockstart,
7436                                                       lockend);
7437                         if (ret)
7438                                 break;
7439
7440                         /*
7441                          * If we found a page that couldn't be invalidated just
7442                          * fall back to buffered.
7443                          */
7444                         ret = invalidate_inode_pages2_range(inode->i_mapping,
7445                                         lockstart >> PAGE_CACHE_SHIFT,
7446                                         lockend >> PAGE_CACHE_SHIFT);
7447                         if (ret)
7448                                 break;
7449                 }
7450
7451                 cond_resched();
7452         }
7453
7454         return ret;
7455 }
7456
7457 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
7458                                            u64 len, u64 orig_start,
7459                                            u64 block_start, u64 block_len,
7460                                            u64 orig_block_len, u64 ram_bytes,
7461                                            int type)
7462 {
7463         struct extent_map_tree *em_tree;
7464         struct extent_map *em;
7465         struct btrfs_root *root = BTRFS_I(inode)->root;
7466         int ret;
7467
7468         em_tree = &BTRFS_I(inode)->extent_tree;
7469         em = alloc_extent_map();
7470         if (!em)
7471                 return ERR_PTR(-ENOMEM);
7472
7473         em->start = start;
7474         em->orig_start = orig_start;
7475         em->mod_start = start;
7476         em->mod_len = len;
7477         em->len = len;
7478         em->block_len = block_len;
7479         em->block_start = block_start;
7480         em->bdev = root->fs_info->fs_devices->latest_bdev;
7481         em->orig_block_len = orig_block_len;
7482         em->ram_bytes = ram_bytes;
7483         em->generation = -1;
7484         set_bit(EXTENT_FLAG_PINNED, &em->flags);
7485         if (type == BTRFS_ORDERED_PREALLOC)
7486                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
7487
7488         do {
7489                 btrfs_drop_extent_cache(inode, em->start,
7490                                 em->start + em->len - 1, 0);
7491                 write_lock(&em_tree->lock);
7492                 ret = add_extent_mapping(em_tree, em, 1);
7493                 write_unlock(&em_tree->lock);
7494         } while (ret == -EEXIST);
7495
7496         if (ret) {
7497                 free_extent_map(em);
7498                 return ERR_PTR(ret);
7499         }
7500
7501         return em;
7502 }
7503
7504 struct btrfs_dio_data {
7505         u64 outstanding_extents;
7506         u64 reserve;
7507 };
7508
7509 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
7510                                    struct buffer_head *bh_result, int create)
7511 {
7512         struct extent_map *em;
7513         struct btrfs_root *root = BTRFS_I(inode)->root;
7514         struct extent_state *cached_state = NULL;
7515         struct btrfs_dio_data *dio_data = NULL;
7516         u64 start = iblock << inode->i_blkbits;
7517         u64 lockstart, lockend;
7518         u64 len = bh_result->b_size;
7519         int unlock_bits = EXTENT_LOCKED;
7520         int ret = 0;
7521
7522         if (create)
7523                 unlock_bits |= EXTENT_DIRTY;
7524         else
7525                 len = min_t(u64, len, root->sectorsize);
7526
7527         lockstart = start;
7528         lockend = start + len - 1;
7529
7530         if (current->journal_info) {
7531                 /*
7532                  * Need to pull our outstanding extents and set journal_info to NULL so
7533                  * that anything that needs to check if there's a transction doesn't get
7534                  * confused.
7535                  */
7536                 dio_data = current->journal_info;
7537                 current->journal_info = NULL;
7538         }
7539
7540         /*
7541          * If this errors out it's because we couldn't invalidate pagecache for
7542          * this range and we need to fallback to buffered.
7543          */
7544         if (lock_extent_direct(inode, lockstart, lockend, &cached_state, create))
7545                 return -ENOTBLK;
7546
7547         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
7548         if (IS_ERR(em)) {
7549                 ret = PTR_ERR(em);
7550                 goto unlock_err;
7551         }
7552
7553         /*
7554          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
7555          * io.  INLINE is special, and we could probably kludge it in here, but
7556          * it's still buffered so for safety lets just fall back to the generic
7557          * buffered path.
7558          *
7559          * For COMPRESSED we _have_ to read the entire extent in so we can
7560          * decompress it, so there will be buffering required no matter what we
7561          * do, so go ahead and fallback to buffered.
7562          *
7563          * We return -ENOTBLK because thats what makes DIO go ahead and go back
7564          * to buffered IO.  Don't blame me, this is the price we pay for using
7565          * the generic code.
7566          */
7567         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
7568             em->block_start == EXTENT_MAP_INLINE) {
7569                 free_extent_map(em);
7570                 ret = -ENOTBLK;
7571                 goto unlock_err;
7572         }
7573
7574         /* Just a good old fashioned hole, return */
7575         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
7576                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
7577                 free_extent_map(em);
7578                 goto unlock_err;
7579         }
7580
7581         /*
7582          * We don't allocate a new extent in the following cases
7583          *
7584          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
7585          * existing extent.
7586          * 2) The extent is marked as PREALLOC.  We're good to go here and can
7587          * just use the extent.
7588          *
7589          */
7590         if (!create) {
7591                 len = min(len, em->len - (start - em->start));
7592                 lockstart = start + len;
7593                 goto unlock;
7594         }
7595
7596         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
7597             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
7598              em->block_start != EXTENT_MAP_HOLE)) {
7599                 int type;
7600                 u64 block_start, orig_start, orig_block_len, ram_bytes;
7601
7602                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7603                         type = BTRFS_ORDERED_PREALLOC;
7604                 else
7605                         type = BTRFS_ORDERED_NOCOW;
7606                 len = min(len, em->len - (start - em->start));
7607                 block_start = em->block_start + (start - em->start);
7608
7609                 if (can_nocow_extent(inode, start, &len, &orig_start,
7610                                      &orig_block_len, &ram_bytes) == 1) {
7611                         if (type == BTRFS_ORDERED_PREALLOC) {
7612                                 free_extent_map(em);
7613                                 em = create_pinned_em(inode, start, len,
7614                                                        orig_start,
7615                                                        block_start, len,
7616                                                        orig_block_len,
7617                                                        ram_bytes, type);
7618                                 if (IS_ERR(em)) {
7619                                         ret = PTR_ERR(em);
7620                                         goto unlock_err;
7621                                 }
7622                         }
7623
7624                         ret = btrfs_add_ordered_extent_dio(inode, start,
7625                                            block_start, len, len, type);
7626                         if (ret) {
7627                                 free_extent_map(em);
7628                                 goto unlock_err;
7629                         }
7630                         goto unlock;
7631                 }
7632         }
7633
7634         /*
7635          * this will cow the extent, reset the len in case we changed
7636          * it above
7637          */
7638         len = bh_result->b_size;
7639         free_extent_map(em);
7640         em = btrfs_new_extent_direct(inode, start, len);
7641         if (IS_ERR(em)) {
7642                 ret = PTR_ERR(em);
7643                 goto unlock_err;
7644         }
7645         len = min(len, em->len - (start - em->start));
7646 unlock:
7647         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7648                 inode->i_blkbits;
7649         bh_result->b_size = len;
7650         bh_result->b_bdev = em->bdev;
7651         set_buffer_mapped(bh_result);
7652         if (create) {
7653                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7654                         set_buffer_new(bh_result);
7655
7656                 /*
7657                  * Need to update the i_size under the extent lock so buffered
7658                  * readers will get the updated i_size when we unlock.
7659                  */
7660                 if (start + len > i_size_read(inode))
7661                         i_size_write(inode, start + len);
7662
7663                 /*
7664                  * If we have an outstanding_extents count still set then we're
7665                  * within our reservation, otherwise we need to adjust our inode
7666                  * counter appropriately.
7667                  */
7668                 if (dio_data->outstanding_extents) {
7669                         (dio_data->outstanding_extents)--;
7670                 } else {
7671                         spin_lock(&BTRFS_I(inode)->lock);
7672                         BTRFS_I(inode)->outstanding_extents++;
7673                         spin_unlock(&BTRFS_I(inode)->lock);
7674                 }
7675
7676                 btrfs_free_reserved_data_space(inode, start, len);
7677                 WARN_ON(dio_data->reserve < len);
7678                 dio_data->reserve -= len;
7679                 current->journal_info = dio_data;
7680         }
7681
7682         /*
7683          * In the case of write we need to clear and unlock the entire range,
7684          * in the case of read we need to unlock only the end area that we
7685          * aren't using if there is any left over space.
7686          */
7687         if (lockstart < lockend) {
7688                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7689                                  lockend, unlock_bits, 1, 0,
7690                                  &cached_state, GFP_NOFS);
7691         } else {
7692                 free_extent_state(cached_state);
7693         }
7694
7695         free_extent_map(em);
7696
7697         return 0;
7698
7699 unlock_err:
7700         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7701                          unlock_bits, 1, 0, &cached_state, GFP_NOFS);
7702         if (dio_data)
7703                 current->journal_info = dio_data;
7704         return ret;
7705 }
7706
7707 static inline int submit_dio_repair_bio(struct inode *inode, struct bio *bio,
7708                                         int rw, int mirror_num)
7709 {
7710         struct btrfs_root *root = BTRFS_I(inode)->root;
7711         int ret;
7712
7713         BUG_ON(rw & REQ_WRITE);
7714
7715         bio_get(bio);
7716
7717         ret = btrfs_bio_wq_end_io(root->fs_info, bio,
7718                                   BTRFS_WQ_ENDIO_DIO_REPAIR);
7719         if (ret)
7720                 goto err;
7721
7722         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
7723 err:
7724         bio_put(bio);
7725         return ret;
7726 }
7727
7728 static int btrfs_check_dio_repairable(struct inode *inode,
7729                                       struct bio *failed_bio,
7730                                       struct io_failure_record *failrec,
7731                                       int failed_mirror)
7732 {
7733         int num_copies;
7734
7735         num_copies = btrfs_num_copies(BTRFS_I(inode)->root->fs_info,
7736                                       failrec->logical, failrec->len);
7737         if (num_copies == 1) {
7738                 /*
7739                  * we only have a single copy of the data, so don't bother with
7740                  * all the retry and error correction code that follows. no
7741                  * matter what the error is, it is very likely to persist.
7742                  */
7743                 pr_debug("Check DIO Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d\n",
7744                          num_copies, failrec->this_mirror, failed_mirror);
7745                 return 0;
7746         }
7747
7748         failrec->failed_mirror = failed_mirror;
7749         failrec->this_mirror++;
7750         if (failrec->this_mirror == failed_mirror)
7751                 failrec->this_mirror++;
7752
7753         if (failrec->this_mirror > num_copies) {
7754                 pr_debug("Check DIO Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d\n",
7755                          num_copies, failrec->this_mirror, failed_mirror);
7756                 return 0;
7757         }
7758
7759         return 1;
7760 }
7761
7762 static int dio_read_error(struct inode *inode, struct bio *failed_bio,
7763                           struct page *page, u64 start, u64 end,
7764                           int failed_mirror, bio_end_io_t *repair_endio,
7765                           void *repair_arg)
7766 {
7767         struct io_failure_record *failrec;
7768         struct bio *bio;
7769         int isector;
7770         int read_mode;
7771         int ret;
7772
7773         BUG_ON(failed_bio->bi_rw & REQ_WRITE);
7774
7775         ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
7776         if (ret)
7777                 return ret;
7778
7779         ret = btrfs_check_dio_repairable(inode, failed_bio, failrec,
7780                                          failed_mirror);
7781         if (!ret) {
7782                 free_io_failure(inode, failrec);
7783                 return -EIO;
7784         }
7785
7786         if (failed_bio->bi_vcnt > 1)
7787                 read_mode = READ_SYNC | REQ_FAILFAST_DEV;
7788         else
7789                 read_mode = READ_SYNC;
7790
7791         isector = start - btrfs_io_bio(failed_bio)->logical;
7792         isector >>= inode->i_sb->s_blocksize_bits;
7793         bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
7794                                       0, isector, repair_endio, repair_arg);
7795         if (!bio) {
7796                 free_io_failure(inode, failrec);
7797                 return -EIO;
7798         }
7799
7800         btrfs_debug(BTRFS_I(inode)->root->fs_info,
7801                     "Repair DIO Read Error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d\n",
7802                     read_mode, failrec->this_mirror, failrec->in_validation);
7803
7804         ret = submit_dio_repair_bio(inode, bio, read_mode,
7805                                     failrec->this_mirror);
7806         if (ret) {
7807                 free_io_failure(inode, failrec);
7808                 bio_put(bio);
7809         }
7810
7811         return ret;
7812 }
7813
7814 struct btrfs_retry_complete {
7815         struct completion done;
7816         struct inode *inode;
7817         u64 start;
7818         int uptodate;
7819 };
7820
7821 static void btrfs_retry_endio_nocsum(struct bio *bio)
7822 {
7823         struct btrfs_retry_complete *done = bio->bi_private;
7824         struct bio_vec *bvec;
7825         int i;
7826
7827         if (bio->bi_error)
7828                 goto end;
7829
7830         done->uptodate = 1;
7831         bio_for_each_segment_all(bvec, bio, i)
7832                 clean_io_failure(done->inode, done->start, bvec->bv_page, 0);
7833 end:
7834         complete(&done->done);
7835         bio_put(bio);
7836 }
7837
7838 static int __btrfs_correct_data_nocsum(struct inode *inode,
7839                                        struct btrfs_io_bio *io_bio)
7840 {
7841         struct bio_vec *bvec;
7842         struct btrfs_retry_complete done;
7843         u64 start;
7844         int i;
7845         int ret;
7846
7847         start = io_bio->logical;
7848         done.inode = inode;
7849
7850         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
7851 try_again:
7852                 done.uptodate = 0;
7853                 done.start = start;
7854                 init_completion(&done.done);
7855
7856                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page, start,
7857                                      start + bvec->bv_len - 1,
7858                                      io_bio->mirror_num,
7859                                      btrfs_retry_endio_nocsum, &done);
7860                 if (ret)
7861                         return ret;
7862
7863                 wait_for_completion(&done.done);
7864
7865                 if (!done.uptodate) {
7866                         /* We might have another mirror, so try again */
7867                         goto try_again;
7868                 }
7869
7870                 start += bvec->bv_len;
7871         }
7872
7873         return 0;
7874 }
7875
7876 static void btrfs_retry_endio(struct bio *bio)
7877 {
7878         struct btrfs_retry_complete *done = bio->bi_private;
7879         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7880         struct bio_vec *bvec;
7881         int uptodate;
7882         int ret;
7883         int i;
7884
7885         if (bio->bi_error)
7886                 goto end;
7887
7888         uptodate = 1;
7889         bio_for_each_segment_all(bvec, bio, i) {
7890                 ret = __readpage_endio_check(done->inode, io_bio, i,
7891                                              bvec->bv_page, 0,
7892                                              done->start, bvec->bv_len);
7893                 if (!ret)
7894                         clean_io_failure(done->inode, done->start,
7895                                          bvec->bv_page, 0);
7896                 else
7897                         uptodate = 0;
7898         }
7899
7900         done->uptodate = uptodate;
7901 end:
7902         complete(&done->done);
7903         bio_put(bio);
7904 }
7905
7906 static int __btrfs_subio_endio_read(struct inode *inode,
7907                                     struct btrfs_io_bio *io_bio, int err)
7908 {
7909         struct bio_vec *bvec;
7910         struct btrfs_retry_complete done;
7911         u64 start;
7912         u64 offset = 0;
7913         int i;
7914         int ret;
7915
7916         err = 0;
7917         start = io_bio->logical;
7918         done.inode = inode;
7919
7920         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
7921                 ret = __readpage_endio_check(inode, io_bio, i, bvec->bv_page,
7922                                              0, start, bvec->bv_len);
7923                 if (likely(!ret))
7924                         goto next;
7925 try_again:
7926                 done.uptodate = 0;
7927                 done.start = start;
7928                 init_completion(&done.done);
7929
7930                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page, start,
7931                                      start + bvec->bv_len - 1,
7932                                      io_bio->mirror_num,
7933                                      btrfs_retry_endio, &done);
7934                 if (ret) {
7935                         err = ret;
7936                         goto next;
7937                 }
7938
7939                 wait_for_completion(&done.done);
7940
7941                 if (!done.uptodate) {
7942                         /* We might have another mirror, so try again */
7943                         goto try_again;
7944                 }
7945 next:
7946                 offset += bvec->bv_len;
7947                 start += bvec->bv_len;
7948         }
7949
7950         return err;
7951 }
7952
7953 static int btrfs_subio_endio_read(struct inode *inode,
7954                                   struct btrfs_io_bio *io_bio, int err)
7955 {
7956         bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
7957
7958         if (skip_csum) {
7959                 if (unlikely(err))
7960                         return __btrfs_correct_data_nocsum(inode, io_bio);
7961                 else
7962                         return 0;
7963         } else {
7964                 return __btrfs_subio_endio_read(inode, io_bio, err);
7965         }
7966 }
7967
7968 static void btrfs_endio_direct_read(struct bio *bio)
7969 {
7970         struct btrfs_dio_private *dip = bio->bi_private;
7971         struct inode *inode = dip->inode;
7972         struct bio *dio_bio;
7973         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7974         int err = bio->bi_error;
7975
7976         if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED)
7977                 err = btrfs_subio_endio_read(inode, io_bio, err);
7978
7979         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
7980                       dip->logical_offset + dip->bytes - 1);
7981         dio_bio = dip->dio_bio;
7982
7983         kfree(dip);
7984
7985         dio_end_io(dio_bio, bio->bi_error);
7986
7987         if (io_bio->end_io)
7988                 io_bio->end_io(io_bio, err);
7989         bio_put(bio);
7990 }
7991
7992 static void btrfs_endio_direct_write(struct bio *bio)
7993 {
7994         struct btrfs_dio_private *dip = bio->bi_private;
7995         struct inode *inode = dip->inode;
7996         struct btrfs_root *root = BTRFS_I(inode)->root;
7997         struct btrfs_ordered_extent *ordered = NULL;
7998         u64 ordered_offset = dip->logical_offset;
7999         u64 ordered_bytes = dip->bytes;
8000         struct bio *dio_bio;
8001         int ret;
8002
8003 again:
8004         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
8005                                                    &ordered_offset,
8006                                                    ordered_bytes,
8007                                                    !bio->bi_error);
8008         if (!ret)
8009                 goto out_test;
8010
8011         btrfs_init_work(&ordered->work, btrfs_endio_write_helper,
8012                         finish_ordered_fn, NULL, NULL);
8013         btrfs_queue_work(root->fs_info->endio_write_workers,
8014                          &ordered->work);
8015 out_test:
8016         /*
8017          * our bio might span multiple ordered extents.  If we haven't
8018          * completed the accounting for the whole dio, go back and try again
8019          */
8020         if (ordered_offset < dip->logical_offset + dip->bytes) {
8021                 ordered_bytes = dip->logical_offset + dip->bytes -
8022                         ordered_offset;
8023                 ordered = NULL;
8024                 goto again;
8025         }
8026         dio_bio = dip->dio_bio;
8027
8028         kfree(dip);
8029
8030         dio_end_io(dio_bio, bio->bi_error);
8031         bio_put(bio);
8032 }
8033
8034 static int __btrfs_submit_bio_start_direct_io(struct inode *inode, int rw,
8035                                     struct bio *bio, int mirror_num,
8036                                     unsigned long bio_flags, u64 offset)
8037 {
8038         int ret;
8039         struct btrfs_root *root = BTRFS_I(inode)->root;
8040         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
8041         BUG_ON(ret); /* -ENOMEM */
8042         return 0;
8043 }
8044
8045 static void btrfs_end_dio_bio(struct bio *bio)
8046 {
8047         struct btrfs_dio_private *dip = bio->bi_private;
8048         int err = bio->bi_error;
8049
8050         if (err)
8051                 btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
8052                            "direct IO failed ino %llu rw %lu sector %#Lx len %u err no %d",
8053                            btrfs_ino(dip->inode), bio->bi_rw,
8054                            (unsigned long long)bio->bi_iter.bi_sector,
8055                            bio->bi_iter.bi_size, err);
8056
8057         if (dip->subio_endio)
8058                 err = dip->subio_endio(dip->inode, btrfs_io_bio(bio), err);
8059
8060         if (err) {
8061                 dip->errors = 1;
8062
8063                 /*
8064                  * before atomic variable goto zero, we must make sure
8065                  * dip->errors is perceived to be set.
8066                  */
8067                 smp_mb__before_atomic();
8068         }
8069
8070         /* if there are more bios still pending for this dio, just exit */
8071         if (!atomic_dec_and_test(&dip->pending_bios))
8072                 goto out;
8073
8074         if (dip->errors) {
8075                 bio_io_error(dip->orig_bio);
8076         } else {
8077                 dip->dio_bio->bi_error = 0;
8078                 bio_endio(dip->orig_bio);
8079         }
8080 out:
8081         bio_put(bio);
8082 }
8083
8084 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
8085                                        u64 first_sector, gfp_t gfp_flags)
8086 {
8087         struct bio *bio;
8088         bio = btrfs_bio_alloc(bdev, first_sector, BIO_MAX_PAGES, gfp_flags);
8089         if (bio)
8090                 bio_associate_current(bio);
8091         return bio;
8092 }
8093
8094 static inline int btrfs_lookup_and_bind_dio_csum(struct btrfs_root *root,
8095                                                  struct inode *inode,
8096                                                  struct btrfs_dio_private *dip,
8097                                                  struct bio *bio,
8098                                                  u64 file_offset)
8099 {
8100         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8101         struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
8102         int ret;
8103
8104         /*
8105          * We load all the csum data we need when we submit
8106          * the first bio to reduce the csum tree search and
8107          * contention.
8108          */
8109         if (dip->logical_offset == file_offset) {
8110                 ret = btrfs_lookup_bio_sums_dio(root, inode, dip->orig_bio,
8111                                                 file_offset);
8112                 if (ret)
8113                         return ret;
8114         }
8115
8116         if (bio == dip->orig_bio)
8117                 return 0;
8118
8119         file_offset -= dip->logical_offset;
8120         file_offset >>= inode->i_sb->s_blocksize_bits;
8121         io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
8122
8123         return 0;
8124 }
8125
8126 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
8127                                          int rw, u64 file_offset, int skip_sum,
8128                                          int async_submit)
8129 {
8130         struct btrfs_dio_private *dip = bio->bi_private;
8131         int write = rw & REQ_WRITE;
8132         struct btrfs_root *root = BTRFS_I(inode)->root;
8133         int ret;
8134
8135         if (async_submit)
8136                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
8137
8138         bio_get(bio);
8139
8140         if (!write) {
8141                 ret = btrfs_bio_wq_end_io(root->fs_info, bio,
8142                                 BTRFS_WQ_ENDIO_DATA);
8143                 if (ret)
8144                         goto err;
8145         }
8146
8147         if (skip_sum)
8148                 goto map;
8149
8150         if (write && async_submit) {
8151                 ret = btrfs_wq_submit_bio(root->fs_info,
8152                                    inode, rw, bio, 0, 0,
8153                                    file_offset,
8154                                    __btrfs_submit_bio_start_direct_io,
8155                                    __btrfs_submit_bio_done);
8156                 goto err;
8157         } else if (write) {
8158                 /*
8159                  * If we aren't doing async submit, calculate the csum of the
8160                  * bio now.
8161                  */
8162                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
8163                 if (ret)
8164                         goto err;
8165         } else {
8166                 ret = btrfs_lookup_and_bind_dio_csum(root, inode, dip, bio,
8167                                                      file_offset);
8168                 if (ret)
8169                         goto err;
8170         }
8171 map:
8172         ret = btrfs_map_bio(root, rw, bio, 0, async_submit);
8173 err:
8174         bio_put(bio);
8175         return ret;
8176 }
8177
8178 static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
8179                                     int skip_sum)
8180 {
8181         struct inode *inode = dip->inode;
8182         struct btrfs_root *root = BTRFS_I(inode)->root;
8183         struct bio *bio;
8184         struct bio *orig_bio = dip->orig_bio;
8185         struct bio_vec *bvec = orig_bio->bi_io_vec;
8186         u64 start_sector = orig_bio->bi_iter.bi_sector;
8187         u64 file_offset = dip->logical_offset;
8188         u64 submit_len = 0;
8189         u64 map_length;
8190         int nr_pages = 0;
8191         int ret;
8192         int async_submit = 0;
8193
8194         map_length = orig_bio->bi_iter.bi_size;
8195         ret = btrfs_map_block(root->fs_info, rw, start_sector << 9,
8196                               &map_length, NULL, 0);
8197         if (ret)
8198                 return -EIO;
8199
8200         if (map_length >= orig_bio->bi_iter.bi_size) {
8201                 bio = orig_bio;
8202                 dip->flags |= BTRFS_DIO_ORIG_BIO_SUBMITTED;
8203                 goto submit;
8204         }
8205
8206         /* async crcs make it difficult to collect full stripe writes. */
8207         if (btrfs_get_alloc_profile(root, 1) & BTRFS_BLOCK_GROUP_RAID56_MASK)
8208                 async_submit = 0;
8209         else
8210                 async_submit = 1;
8211
8212         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
8213         if (!bio)
8214                 return -ENOMEM;
8215
8216         bio->bi_private = dip;
8217         bio->bi_end_io = btrfs_end_dio_bio;
8218         btrfs_io_bio(bio)->logical = file_offset;
8219         atomic_inc(&dip->pending_bios);
8220
8221         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
8222                 if (map_length < submit_len + bvec->bv_len ||
8223                     bio_add_page(bio, bvec->bv_page, bvec->bv_len,
8224                                  bvec->bv_offset) < bvec->bv_len) {
8225                         /*
8226                          * inc the count before we submit the bio so
8227                          * we know the end IO handler won't happen before
8228                          * we inc the count. Otherwise, the dip might get freed
8229                          * before we're done setting it up
8230                          */
8231                         atomic_inc(&dip->pending_bios);
8232                         ret = __btrfs_submit_dio_bio(bio, inode, rw,
8233                                                      file_offset, skip_sum,
8234                                                      async_submit);
8235                         if (ret) {
8236                                 bio_put(bio);
8237                                 atomic_dec(&dip->pending_bios);
8238                                 goto out_err;
8239                         }
8240
8241                         start_sector += submit_len >> 9;
8242                         file_offset += submit_len;
8243
8244                         submit_len = 0;
8245                         nr_pages = 0;
8246
8247                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
8248                                                   start_sector, GFP_NOFS);
8249                         if (!bio)
8250                                 goto out_err;
8251                         bio->bi_private = dip;
8252                         bio->bi_end_io = btrfs_end_dio_bio;
8253                         btrfs_io_bio(bio)->logical = file_offset;
8254
8255                         map_length = orig_bio->bi_iter.bi_size;
8256                         ret = btrfs_map_block(root->fs_info, rw,
8257                                               start_sector << 9,
8258                                               &map_length, NULL, 0);
8259                         if (ret) {
8260                                 bio_put(bio);
8261                                 goto out_err;
8262                         }
8263                 } else {
8264                         submit_len += bvec->bv_len;
8265                         nr_pages++;
8266                         bvec++;
8267                 }
8268         }
8269
8270 submit:
8271         ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum,
8272                                      async_submit);
8273         if (!ret)
8274                 return 0;
8275
8276         bio_put(bio);
8277 out_err:
8278         dip->errors = 1;
8279         /*
8280          * before atomic variable goto zero, we must
8281          * make sure dip->errors is perceived to be set.
8282          */
8283         smp_mb__before_atomic();
8284         if (atomic_dec_and_test(&dip->pending_bios))
8285                 bio_io_error(dip->orig_bio);
8286
8287         /* bio_end_io() will handle error, so we needn't return it */
8288         return 0;
8289 }
8290
8291 static void btrfs_submit_direct(int rw, struct bio *dio_bio,
8292                                 struct inode *inode, loff_t file_offset)
8293 {
8294         struct btrfs_dio_private *dip = NULL;
8295         struct bio *io_bio = NULL;
8296         struct btrfs_io_bio *btrfs_bio;
8297         int skip_sum;
8298         int write = rw & REQ_WRITE;
8299         int ret = 0;
8300
8301         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
8302
8303         io_bio = btrfs_bio_clone(dio_bio, GFP_NOFS);
8304         if (!io_bio) {
8305                 ret = -ENOMEM;
8306                 goto free_ordered;
8307         }
8308
8309         dip = kzalloc(sizeof(*dip), GFP_NOFS);
8310         if (!dip) {
8311                 ret = -ENOMEM;
8312                 goto free_ordered;
8313         }
8314
8315         dip->private = dio_bio->bi_private;
8316         dip->inode = inode;
8317         dip->logical_offset = file_offset;
8318         dip->bytes = dio_bio->bi_iter.bi_size;
8319         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
8320         io_bio->bi_private = dip;
8321         dip->orig_bio = io_bio;
8322         dip->dio_bio = dio_bio;
8323         atomic_set(&dip->pending_bios, 0);
8324         btrfs_bio = btrfs_io_bio(io_bio);
8325         btrfs_bio->logical = file_offset;
8326
8327         if (write) {
8328                 io_bio->bi_end_io = btrfs_endio_direct_write;
8329         } else {
8330                 io_bio->bi_end_io = btrfs_endio_direct_read;
8331                 dip->subio_endio = btrfs_subio_endio_read;
8332         }
8333
8334         ret = btrfs_submit_direct_hook(rw, dip, skip_sum);
8335         if (!ret)
8336                 return;
8337
8338         if (btrfs_bio->end_io)
8339                 btrfs_bio->end_io(btrfs_bio, ret);
8340
8341 free_ordered:
8342         /*
8343          * If we arrived here it means either we failed to submit the dip
8344          * or we either failed to clone the dio_bio or failed to allocate the
8345          * dip. If we cloned the dio_bio and allocated the dip, we can just
8346          * call bio_endio against our io_bio so that we get proper resource
8347          * cleanup if we fail to submit the dip, otherwise, we must do the
8348          * same as btrfs_endio_direct_[write|read] because we can't call these
8349          * callbacks - they require an allocated dip and a clone of dio_bio.
8350          */
8351         if (io_bio && dip) {
8352                 io_bio->bi_error = -EIO;
8353                 bio_endio(io_bio);
8354                 /*
8355                  * The end io callbacks free our dip, do the final put on io_bio
8356                  * and all the cleanup and final put for dio_bio (through
8357                  * dio_end_io()).
8358                  */
8359                 dip = NULL;
8360                 io_bio = NULL;
8361         } else {
8362                 if (write) {
8363                         struct btrfs_ordered_extent *ordered;
8364
8365                         ordered = btrfs_lookup_ordered_extent(inode,
8366                                                               file_offset);
8367                         set_bit(BTRFS_ORDERED_IOERR, &ordered->flags);
8368                         /*
8369                          * Decrements our ref on the ordered extent and removes
8370                          * the ordered extent from the inode's ordered tree,
8371                          * doing all the proper resource cleanup such as for the
8372                          * reserved space and waking up any waiters for this
8373                          * ordered extent (through btrfs_remove_ordered_extent).
8374                          */
8375                         btrfs_finish_ordered_io(ordered);
8376                 } else {
8377                         unlock_extent(&BTRFS_I(inode)->io_tree, file_offset,
8378                               file_offset + dio_bio->bi_iter.bi_size - 1);
8379                 }
8380                 dio_bio->bi_error = -EIO;
8381                 /*
8382                  * Releases and cleans up our dio_bio, no need to bio_put()
8383                  * nor bio_endio()/bio_io_error() against dio_bio.
8384                  */
8385                 dio_end_io(dio_bio, ret);
8386         }
8387         if (io_bio)
8388                 bio_put(io_bio);
8389         kfree(dip);
8390 }
8391
8392 static ssize_t check_direct_IO(struct btrfs_root *root, struct kiocb *iocb,
8393                         const struct iov_iter *iter, loff_t offset)
8394 {
8395         int seg;
8396         int i;
8397         unsigned blocksize_mask = root->sectorsize - 1;
8398         ssize_t retval = -EINVAL;
8399
8400         if (offset & blocksize_mask)
8401                 goto out;
8402
8403         if (iov_iter_alignment(iter) & blocksize_mask)
8404                 goto out;
8405
8406         /* If this is a write we don't need to check anymore */
8407         if (iov_iter_rw(iter) == WRITE)
8408                 return 0;
8409         /*
8410          * Check to make sure we don't have duplicate iov_base's in this
8411          * iovec, if so return EINVAL, otherwise we'll get csum errors
8412          * when reading back.
8413          */
8414         for (seg = 0; seg < iter->nr_segs; seg++) {
8415                 for (i = seg + 1; i < iter->nr_segs; i++) {
8416                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
8417                                 goto out;
8418                 }
8419         }
8420         retval = 0;
8421 out:
8422         return retval;
8423 }
8424
8425 static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
8426                                loff_t offset)
8427 {
8428         struct file *file = iocb->ki_filp;
8429         struct inode *inode = file->f_mapping->host;
8430         struct btrfs_root *root = BTRFS_I(inode)->root;
8431         struct btrfs_dio_data dio_data = { 0 };
8432         size_t count = 0;
8433         int flags = 0;
8434         bool wakeup = true;
8435         bool relock = false;
8436         ssize_t ret;
8437
8438         if (check_direct_IO(BTRFS_I(inode)->root, iocb, iter, offset))
8439                 return 0;
8440
8441         inode_dio_begin(inode);
8442         smp_mb__after_atomic();
8443
8444         /*
8445          * The generic stuff only does filemap_write_and_wait_range, which
8446          * isn't enough if we've written compressed pages to this area, so
8447          * we need to flush the dirty pages again to make absolutely sure
8448          * that any outstanding dirty pages are on disk.
8449          */
8450         count = iov_iter_count(iter);
8451         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8452                      &BTRFS_I(inode)->runtime_flags))
8453                 filemap_fdatawrite_range(inode->i_mapping, offset,
8454                                          offset + count - 1);
8455
8456         if (iov_iter_rw(iter) == WRITE) {
8457                 /*
8458                  * If the write DIO is beyond the EOF, we need update
8459                  * the isize, but it is protected by i_mutex. So we can
8460                  * not unlock the i_mutex at this case.
8461                  */
8462                 if (offset + count <= inode->i_size) {
8463                         mutex_unlock(&inode->i_mutex);
8464                         relock = true;
8465                 }
8466                 ret = btrfs_delalloc_reserve_space(inode, offset, count);
8467                 if (ret)
8468                         goto out;
8469                 dio_data.outstanding_extents = div64_u64(count +
8470                                                 BTRFS_MAX_EXTENT_SIZE - 1,
8471                                                 BTRFS_MAX_EXTENT_SIZE);
8472
8473                 /*
8474                  * We need to know how many extents we reserved so that we can
8475                  * do the accounting properly if we go over the number we
8476                  * originally calculated.  Abuse current->journal_info for this.
8477                  */
8478                 dio_data.reserve = round_up(count, root->sectorsize);
8479                 current->journal_info = &dio_data;
8480         } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
8481                                      &BTRFS_I(inode)->runtime_flags)) {
8482                 inode_dio_end(inode);
8483                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
8484                 wakeup = false;
8485         }
8486
8487         ret = __blockdev_direct_IO(iocb, inode,
8488                                    BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
8489                                    iter, offset, btrfs_get_blocks_direct, NULL,
8490                                    btrfs_submit_direct, flags);
8491         if (iov_iter_rw(iter) == WRITE) {
8492                 current->journal_info = NULL;
8493                 if (ret < 0 && ret != -EIOCBQUEUED) {
8494                         if (dio_data.reserve)
8495                                 btrfs_delalloc_release_space(inode, offset,
8496                                                              dio_data.reserve);
8497                 } else if (ret >= 0 && (size_t)ret < count)
8498                         btrfs_delalloc_release_space(inode, offset,
8499                                                      count - (size_t)ret);
8500         }
8501 out:
8502         if (wakeup)
8503                 inode_dio_end(inode);
8504         if (relock)
8505                 mutex_lock(&inode->i_mutex);
8506
8507         return ret;
8508 }
8509
8510 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
8511
8512 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
8513                 __u64 start, __u64 len)
8514 {
8515         int     ret;
8516
8517         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
8518         if (ret)
8519                 return ret;
8520
8521         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
8522 }
8523
8524 int btrfs_readpage(struct file *file, struct page *page)
8525 {
8526         struct extent_io_tree *tree;
8527         tree = &BTRFS_I(page->mapping->host)->io_tree;
8528         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
8529 }
8530
8531 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
8532 {
8533         struct extent_io_tree *tree;
8534
8535
8536         if (current->flags & PF_MEMALLOC) {
8537                 redirty_page_for_writepage(wbc, page);
8538                 unlock_page(page);
8539                 return 0;
8540         }
8541         tree = &BTRFS_I(page->mapping->host)->io_tree;
8542         return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
8543 }
8544
8545 static int btrfs_writepages(struct address_space *mapping,
8546                             struct writeback_control *wbc)
8547 {
8548         struct extent_io_tree *tree;
8549
8550         tree = &BTRFS_I(mapping->host)->io_tree;
8551         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
8552 }
8553
8554 static int
8555 btrfs_readpages(struct file *file, struct address_space *mapping,
8556                 struct list_head *pages, unsigned nr_pages)
8557 {
8558         struct extent_io_tree *tree;
8559         tree = &BTRFS_I(mapping->host)->io_tree;
8560         return extent_readpages(tree, mapping, pages, nr_pages,
8561                                 btrfs_get_extent);
8562 }
8563 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8564 {
8565         struct extent_io_tree *tree;
8566         struct extent_map_tree *map;
8567         int ret;
8568
8569         tree = &BTRFS_I(page->mapping->host)->io_tree;
8570         map = &BTRFS_I(page->mapping->host)->extent_tree;
8571         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
8572         if (ret == 1) {
8573                 ClearPagePrivate(page);
8574                 set_page_private(page, 0);
8575                 page_cache_release(page);
8576         }
8577         return ret;
8578 }
8579
8580 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8581 {
8582         if (PageWriteback(page) || PageDirty(page))
8583                 return 0;
8584         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
8585 }
8586
8587 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
8588                                  unsigned int length)
8589 {
8590         struct inode *inode = page->mapping->host;
8591         struct extent_io_tree *tree;
8592         struct btrfs_ordered_extent *ordered;
8593         struct extent_state *cached_state = NULL;
8594         u64 page_start = page_offset(page);
8595         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
8596         int inode_evicting = inode->i_state & I_FREEING;
8597
8598         /*
8599          * we have the page locked, so new writeback can't start,
8600          * and the dirty bit won't be cleared while we are here.
8601          *
8602          * Wait for IO on this page so that we can safely clear
8603          * the PagePrivate2 bit and do ordered accounting
8604          */
8605         wait_on_page_writeback(page);
8606
8607         tree = &BTRFS_I(inode)->io_tree;
8608         if (offset) {
8609                 btrfs_releasepage(page, GFP_NOFS);
8610                 return;
8611         }
8612
8613         if (!inode_evicting)
8614                 lock_extent_bits(tree, page_start, page_end, 0, &cached_state);
8615         ordered = btrfs_lookup_ordered_extent(inode, page_start);
8616         if (ordered) {
8617                 /*
8618                  * IO on this page will never be started, so we need
8619                  * to account for any ordered extents now
8620                  */
8621                 if (!inode_evicting)
8622                         clear_extent_bit(tree, page_start, page_end,
8623                                          EXTENT_DIRTY | EXTENT_DELALLOC |
8624                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
8625                                          EXTENT_DEFRAG, 1, 0, &cached_state,
8626                                          GFP_NOFS);
8627                 /*
8628                  * whoever cleared the private bit is responsible
8629                  * for the finish_ordered_io
8630                  */
8631                 if (TestClearPagePrivate2(page)) {
8632                         struct btrfs_ordered_inode_tree *tree;
8633                         u64 new_len;
8634
8635                         tree = &BTRFS_I(inode)->ordered_tree;
8636
8637                         spin_lock_irq(&tree->lock);
8638                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
8639                         new_len = page_start - ordered->file_offset;
8640                         if (new_len < ordered->truncated_len)
8641                                 ordered->truncated_len = new_len;
8642                         spin_unlock_irq(&tree->lock);
8643
8644                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
8645                                                            page_start,
8646                                                            PAGE_CACHE_SIZE, 1))
8647                                 btrfs_finish_ordered_io(ordered);
8648                 }
8649                 btrfs_put_ordered_extent(ordered);
8650                 if (!inode_evicting) {
8651                         cached_state = NULL;
8652                         lock_extent_bits(tree, page_start, page_end, 0,
8653                                          &cached_state);
8654                 }
8655         }
8656
8657         /*
8658          * Qgroup reserved space handler
8659          * Page here will be either
8660          * 1) Already written to disk
8661          *    In this case, its reserved space is released from data rsv map
8662          *    and will be freed by delayed_ref handler finally.
8663          *    So even we call qgroup_free_data(), it won't decrease reserved
8664          *    space.
8665          * 2) Not written to disk
8666          *    This means the reserved space should be freed here.
8667          */
8668         btrfs_qgroup_free_data(inode, page_start, PAGE_CACHE_SIZE);
8669         if (!inode_evicting) {
8670                 clear_extent_bit(tree, page_start, page_end,
8671                                  EXTENT_LOCKED | EXTENT_DIRTY |
8672                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
8673                                  EXTENT_DEFRAG, 1, 1,
8674                                  &cached_state, GFP_NOFS);
8675
8676                 __btrfs_releasepage(page, GFP_NOFS);
8677         }
8678
8679         ClearPageChecked(page);
8680         if (PagePrivate(page)) {
8681                 ClearPagePrivate(page);
8682                 set_page_private(page, 0);
8683                 page_cache_release(page);
8684         }
8685 }
8686
8687 /*
8688  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
8689  * called from a page fault handler when a page is first dirtied. Hence we must
8690  * be careful to check for EOF conditions here. We set the page up correctly
8691  * for a written page which means we get ENOSPC checking when writing into
8692  * holes and correct delalloc and unwritten extent mapping on filesystems that
8693  * support these features.
8694  *
8695  * We are not allowed to take the i_mutex here so we have to play games to
8696  * protect against truncate races as the page could now be beyond EOF.  Because
8697  * vmtruncate() writes the inode size before removing pages, once we have the
8698  * page lock we can determine safely if the page is beyond EOF. If it is not
8699  * beyond EOF, then the page is guaranteed safe against truncation until we
8700  * unlock the page.
8701  */
8702 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
8703 {
8704         struct page *page = vmf->page;
8705         struct inode *inode = file_inode(vma->vm_file);
8706         struct btrfs_root *root = BTRFS_I(inode)->root;
8707         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
8708         struct btrfs_ordered_extent *ordered;
8709         struct extent_state *cached_state = NULL;
8710         char *kaddr;
8711         unsigned long zero_start;
8712         loff_t size;
8713         int ret;
8714         int reserved = 0;
8715         u64 page_start;
8716         u64 page_end;
8717
8718         sb_start_pagefault(inode->i_sb);
8719         page_start = page_offset(page);
8720         page_end = page_start + PAGE_CACHE_SIZE - 1;
8721
8722         ret = btrfs_delalloc_reserve_space(inode, page_start,
8723                                            PAGE_CACHE_SIZE);
8724         if (!ret) {
8725                 ret = file_update_time(vma->vm_file);
8726                 reserved = 1;
8727         }
8728         if (ret) {
8729                 if (ret == -ENOMEM)
8730                         ret = VM_FAULT_OOM;
8731                 else /* -ENOSPC, -EIO, etc */
8732                         ret = VM_FAULT_SIGBUS;
8733                 if (reserved)
8734                         goto out;
8735                 goto out_noreserve;
8736         }
8737
8738         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
8739 again:
8740         lock_page(page);
8741         size = i_size_read(inode);
8742
8743         if ((page->mapping != inode->i_mapping) ||
8744             (page_start >= size)) {
8745                 /* page got truncated out from underneath us */
8746                 goto out_unlock;
8747         }
8748         wait_on_page_writeback(page);
8749
8750         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
8751         set_page_extent_mapped(page);
8752
8753         /*
8754          * we can't set the delalloc bits if there are pending ordered
8755          * extents.  Drop our locks and wait for them to finish
8756          */
8757         ordered = btrfs_lookup_ordered_extent(inode, page_start);
8758         if (ordered) {
8759                 unlock_extent_cached(io_tree, page_start, page_end,
8760                                      &cached_state, GFP_NOFS);
8761                 unlock_page(page);
8762                 btrfs_start_ordered_extent(inode, ordered, 1);
8763                 btrfs_put_ordered_extent(ordered);
8764                 goto again;
8765         }
8766
8767         /*
8768          * XXX - page_mkwrite gets called every time the page is dirtied, even
8769          * if it was already dirty, so for space accounting reasons we need to
8770          * clear any delalloc bits for the range we are fixing to save.  There
8771          * is probably a better way to do this, but for now keep consistent with
8772          * prepare_pages in the normal write path.
8773          */
8774         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
8775                           EXTENT_DIRTY | EXTENT_DELALLOC |
8776                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
8777                           0, 0, &cached_state, GFP_NOFS);
8778
8779         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
8780                                         &cached_state);
8781         if (ret) {
8782                 unlock_extent_cached(io_tree, page_start, page_end,
8783                                      &cached_state, GFP_NOFS);
8784                 ret = VM_FAULT_SIGBUS;
8785                 goto out_unlock;
8786         }
8787         ret = 0;
8788
8789         /* page is wholly or partially inside EOF */
8790         if (page_start + PAGE_CACHE_SIZE > size)
8791                 zero_start = size & ~PAGE_CACHE_MASK;
8792         else
8793                 zero_start = PAGE_CACHE_SIZE;
8794
8795         if (zero_start != PAGE_CACHE_SIZE) {
8796                 kaddr = kmap(page);
8797                 memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
8798                 flush_dcache_page(page);
8799                 kunmap(page);
8800         }
8801         ClearPageChecked(page);
8802         set_page_dirty(page);
8803         SetPageUptodate(page);
8804
8805         BTRFS_I(inode)->last_trans = root->fs_info->generation;
8806         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
8807         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
8808
8809         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
8810
8811 out_unlock:
8812         if (!ret) {
8813                 sb_end_pagefault(inode->i_sb);
8814                 return VM_FAULT_LOCKED;
8815         }
8816         unlock_page(page);
8817 out:
8818         btrfs_delalloc_release_space(inode, page_start, PAGE_CACHE_SIZE);
8819 out_noreserve:
8820         sb_end_pagefault(inode->i_sb);
8821         return ret;
8822 }
8823
8824 static int btrfs_truncate(struct inode *inode)
8825 {
8826         struct btrfs_root *root = BTRFS_I(inode)->root;
8827         struct btrfs_block_rsv *rsv;
8828         int ret = 0;
8829         int err = 0;
8830         struct btrfs_trans_handle *trans;
8831         u64 mask = root->sectorsize - 1;
8832         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
8833
8834         ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
8835                                        (u64)-1);
8836         if (ret)
8837                 return ret;
8838
8839         /*
8840          * Yes ladies and gentelment, this is indeed ugly.  The fact is we have
8841          * 3 things going on here
8842          *
8843          * 1) We need to reserve space for our orphan item and the space to
8844          * delete our orphan item.  Lord knows we don't want to have a dangling
8845          * orphan item because we didn't reserve space to remove it.
8846          *
8847          * 2) We need to reserve space to update our inode.
8848          *
8849          * 3) We need to have something to cache all the space that is going to
8850          * be free'd up by the truncate operation, but also have some slack
8851          * space reserved in case it uses space during the truncate (thank you
8852          * very much snapshotting).
8853          *
8854          * And we need these to all be seperate.  The fact is we can use alot of
8855          * space doing the truncate, and we have no earthly idea how much space
8856          * we will use, so we need the truncate reservation to be seperate so it
8857          * doesn't end up using space reserved for updating the inode or
8858          * removing the orphan item.  We also need to be able to stop the
8859          * transaction and start a new one, which means we need to be able to
8860          * update the inode several times, and we have no idea of knowing how
8861          * many times that will be, so we can't just reserve 1 item for the
8862          * entirety of the opration, so that has to be done seperately as well.
8863          * Then there is the orphan item, which does indeed need to be held on
8864          * to for the whole operation, and we need nobody to touch this reserved
8865          * space except the orphan code.
8866          *
8867          * So that leaves us with
8868          *
8869          * 1) root->orphan_block_rsv - for the orphan deletion.
8870          * 2) rsv - for the truncate reservation, which we will steal from the
8871          * transaction reservation.
8872          * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
8873          * updating the inode.
8874          */
8875         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
8876         if (!rsv)
8877                 return -ENOMEM;
8878         rsv->size = min_size;
8879         rsv->failfast = 1;
8880
8881         /*
8882          * 1 for the truncate slack space
8883          * 1 for updating the inode.
8884          */
8885         trans = btrfs_start_transaction(root, 2);
8886         if (IS_ERR(trans)) {
8887                 err = PTR_ERR(trans);
8888                 goto out;
8889         }
8890
8891         /* Migrate the slack space for the truncate to our reserve */
8892         ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
8893                                       min_size);
8894         BUG_ON(ret);
8895
8896         /*
8897          * So if we truncate and then write and fsync we normally would just
8898          * write the extents that changed, which is a problem if we need to
8899          * first truncate that entire inode.  So set this flag so we write out
8900          * all of the extents in the inode to the sync log so we're completely
8901          * safe.
8902          */
8903         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
8904         trans->block_rsv = rsv;
8905
8906         while (1) {
8907                 ret = btrfs_truncate_inode_items(trans, root, inode,
8908                                                  inode->i_size,
8909                                                  BTRFS_EXTENT_DATA_KEY);
8910                 if (ret != -ENOSPC && ret != -EAGAIN) {
8911                         err = ret;
8912                         break;
8913                 }
8914
8915                 trans->block_rsv = &root->fs_info->trans_block_rsv;
8916                 ret = btrfs_update_inode(trans, root, inode);
8917                 if (ret) {
8918                         err = ret;
8919                         break;
8920                 }
8921
8922                 btrfs_end_transaction(trans, root);
8923                 btrfs_btree_balance_dirty(root);
8924
8925                 trans = btrfs_start_transaction(root, 2);
8926                 if (IS_ERR(trans)) {
8927                         ret = err = PTR_ERR(trans);
8928                         trans = NULL;
8929                         break;
8930                 }
8931
8932                 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
8933                                               rsv, min_size);
8934                 BUG_ON(ret);    /* shouldn't happen */
8935                 trans->block_rsv = rsv;
8936         }
8937
8938         if (ret == 0 && inode->i_nlink > 0) {
8939                 trans->block_rsv = root->orphan_block_rsv;
8940                 ret = btrfs_orphan_del(trans, inode);
8941                 if (ret)
8942                         err = ret;
8943         }
8944
8945         if (trans) {
8946                 trans->block_rsv = &root->fs_info->trans_block_rsv;
8947                 ret = btrfs_update_inode(trans, root, inode);
8948                 if (ret && !err)
8949                         err = ret;
8950
8951                 ret = btrfs_end_transaction(trans, root);
8952                 btrfs_btree_balance_dirty(root);
8953         }
8954
8955 out:
8956         btrfs_free_block_rsv(root, rsv);
8957
8958         if (ret && !err)
8959                 err = ret;
8960
8961         return err;
8962 }
8963
8964 /*
8965  * create a new subvolume directory/inode (helper for the ioctl).
8966  */
8967 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
8968                              struct btrfs_root *new_root,
8969                              struct btrfs_root *parent_root,
8970                              u64 new_dirid)
8971 {
8972         struct inode *inode;
8973         int err;
8974         u64 index = 0;
8975
8976         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
8977                                 new_dirid, new_dirid,
8978                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
8979                                 &index);
8980         if (IS_ERR(inode))
8981                 return PTR_ERR(inode);
8982         inode->i_op = &btrfs_dir_inode_operations;
8983         inode->i_fop = &btrfs_dir_file_operations;
8984
8985         set_nlink(inode, 1);
8986         btrfs_i_size_write(inode, 0);
8987         unlock_new_inode(inode);
8988
8989         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
8990         if (err)
8991                 btrfs_err(new_root->fs_info,
8992                           "error inheriting subvolume %llu properties: %d",
8993                           new_root->root_key.objectid, err);
8994
8995         err = btrfs_update_inode(trans, new_root, inode);
8996
8997         iput(inode);
8998         return err;
8999 }
9000
9001 struct inode *btrfs_alloc_inode(struct super_block *sb)
9002 {
9003         struct btrfs_inode *ei;
9004         struct inode *inode;
9005
9006         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
9007         if (!ei)
9008                 return NULL;
9009
9010         ei->root = NULL;
9011         ei->generation = 0;
9012         ei->last_trans = 0;
9013         ei->last_sub_trans = 0;
9014         ei->logged_trans = 0;
9015         ei->delalloc_bytes = 0;
9016         ei->defrag_bytes = 0;
9017         ei->disk_i_size = 0;
9018         ei->flags = 0;
9019         ei->csum_bytes = 0;
9020         ei->index_cnt = (u64)-1;
9021         ei->dir_index = 0;
9022         ei->last_unlink_trans = 0;
9023         ei->last_log_commit = 0;
9024
9025         spin_lock_init(&ei->lock);
9026         ei->outstanding_extents = 0;
9027         ei->reserved_extents = 0;
9028
9029         ei->runtime_flags = 0;
9030         ei->force_compress = BTRFS_COMPRESS_NONE;
9031
9032         ei->delayed_node = NULL;
9033
9034         ei->i_otime.tv_sec = 0;
9035         ei->i_otime.tv_nsec = 0;
9036
9037         inode = &ei->vfs_inode;
9038         extent_map_tree_init(&ei->extent_tree);
9039         extent_io_tree_init(&ei->io_tree, &inode->i_data);
9040         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
9041         ei->io_tree.track_uptodate = 1;
9042         ei->io_failure_tree.track_uptodate = 1;
9043         atomic_set(&ei->sync_writers, 0);
9044         mutex_init(&ei->log_mutex);
9045         mutex_init(&ei->delalloc_mutex);
9046         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
9047         INIT_LIST_HEAD(&ei->delalloc_inodes);
9048         RB_CLEAR_NODE(&ei->rb_node);
9049
9050         return inode;
9051 }
9052
9053 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
9054 void btrfs_test_destroy_inode(struct inode *inode)
9055 {
9056         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
9057         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9058 }
9059 #endif
9060
9061 static void btrfs_i_callback(struct rcu_head *head)
9062 {
9063         struct inode *inode = container_of(head, struct inode, i_rcu);
9064         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9065 }
9066
9067 void btrfs_destroy_inode(struct inode *inode)
9068 {
9069         struct btrfs_ordered_extent *ordered;
9070         struct btrfs_root *root = BTRFS_I(inode)->root;
9071
9072         WARN_ON(!hlist_empty(&inode->i_dentry));
9073         WARN_ON(inode->i_data.nrpages);
9074         WARN_ON(BTRFS_I(inode)->outstanding_extents);
9075         WARN_ON(BTRFS_I(inode)->reserved_extents);
9076         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
9077         WARN_ON(BTRFS_I(inode)->csum_bytes);
9078         WARN_ON(BTRFS_I(inode)->defrag_bytes);
9079
9080         /*
9081          * This can happen where we create an inode, but somebody else also
9082          * created the same inode and we need to destroy the one we already
9083          * created.
9084          */
9085         if (!root)
9086                 goto free;
9087
9088         if (test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
9089                      &BTRFS_I(inode)->runtime_flags)) {
9090                 btrfs_info(root->fs_info, "inode %llu still on the orphan list",
9091                         btrfs_ino(inode));
9092                 atomic_dec(&root->orphan_inodes);
9093         }
9094
9095         while (1) {
9096                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
9097                 if (!ordered)
9098                         break;
9099                 else {
9100                         btrfs_err(root->fs_info, "found ordered extent %llu %llu on inode cleanup",
9101                                 ordered->file_offset, ordered->len);
9102                         btrfs_remove_ordered_extent(inode, ordered);
9103                         btrfs_put_ordered_extent(ordered);
9104                         btrfs_put_ordered_extent(ordered);
9105                 }
9106         }
9107         btrfs_qgroup_check_reserved_leak(inode);
9108         inode_tree_del(inode);
9109         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
9110 free:
9111         call_rcu(&inode->i_rcu, btrfs_i_callback);
9112 }
9113
9114 int btrfs_drop_inode(struct inode *inode)
9115 {
9116         struct btrfs_root *root = BTRFS_I(inode)->root;
9117
9118         if (root == NULL)
9119                 return 1;
9120
9121         /* the snap/subvol tree is on deleting */
9122         if (btrfs_root_refs(&root->root_item) == 0)
9123                 return 1;
9124         else
9125                 return generic_drop_inode(inode);
9126 }
9127
9128 static void init_once(void *foo)
9129 {
9130         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
9131
9132         inode_init_once(&ei->vfs_inode);
9133 }
9134
9135 void btrfs_destroy_cachep(void)
9136 {
9137         /*
9138          * Make sure all delayed rcu free inodes are flushed before we
9139          * destroy cache.
9140          */
9141         rcu_barrier();
9142         if (btrfs_inode_cachep)
9143                 kmem_cache_destroy(btrfs_inode_cachep);
9144         if (btrfs_trans_handle_cachep)
9145                 kmem_cache_destroy(btrfs_trans_handle_cachep);
9146         if (btrfs_transaction_cachep)
9147                 kmem_cache_destroy(btrfs_transaction_cachep);
9148         if (btrfs_path_cachep)
9149                 kmem_cache_destroy(btrfs_path_cachep);
9150         if (btrfs_free_space_cachep)
9151                 kmem_cache_destroy(btrfs_free_space_cachep);
9152         if (btrfs_delalloc_work_cachep)
9153                 kmem_cache_destroy(btrfs_delalloc_work_cachep);
9154 }
9155
9156 int btrfs_init_cachep(void)
9157 {
9158         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
9159                         sizeof(struct btrfs_inode), 0,
9160                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, init_once);
9161         if (!btrfs_inode_cachep)
9162                 goto fail;
9163
9164         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
9165                         sizeof(struct btrfs_trans_handle), 0,
9166                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9167         if (!btrfs_trans_handle_cachep)
9168                 goto fail;
9169
9170         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
9171                         sizeof(struct btrfs_transaction), 0,
9172                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9173         if (!btrfs_transaction_cachep)
9174                 goto fail;
9175
9176         btrfs_path_cachep = kmem_cache_create("btrfs_path",
9177                         sizeof(struct btrfs_path), 0,
9178                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9179         if (!btrfs_path_cachep)
9180                 goto fail;
9181
9182         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
9183                         sizeof(struct btrfs_free_space), 0,
9184                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9185         if (!btrfs_free_space_cachep)
9186                 goto fail;
9187
9188         btrfs_delalloc_work_cachep = kmem_cache_create("btrfs_delalloc_work",
9189                         sizeof(struct btrfs_delalloc_work), 0,
9190                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
9191                         NULL);
9192         if (!btrfs_delalloc_work_cachep)
9193                 goto fail;
9194
9195         return 0;
9196 fail:
9197         btrfs_destroy_cachep();
9198         return -ENOMEM;
9199 }
9200
9201 static int btrfs_getattr(struct vfsmount *mnt,
9202                          struct dentry *dentry, struct kstat *stat)
9203 {
9204         u64 delalloc_bytes;
9205         struct inode *inode = d_inode(dentry);
9206         u32 blocksize = inode->i_sb->s_blocksize;
9207
9208         generic_fillattr(inode, stat);
9209         stat->dev = BTRFS_I(inode)->root->anon_dev;
9210         stat->blksize = PAGE_CACHE_SIZE;
9211
9212         spin_lock(&BTRFS_I(inode)->lock);
9213         delalloc_bytes = BTRFS_I(inode)->delalloc_bytes;
9214         spin_unlock(&BTRFS_I(inode)->lock);
9215         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
9216                         ALIGN(delalloc_bytes, blocksize)) >> 9;
9217         return 0;
9218 }
9219
9220 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
9221                            struct inode *new_dir, struct dentry *new_dentry)
9222 {
9223         struct btrfs_trans_handle *trans;
9224         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9225         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9226         struct inode *new_inode = d_inode(new_dentry);
9227         struct inode *old_inode = d_inode(old_dentry);
9228         struct timespec ctime = CURRENT_TIME;
9229         u64 index = 0;
9230         u64 root_objectid;
9231         int ret;
9232         u64 old_ino = btrfs_ino(old_inode);
9233
9234         if (btrfs_ino(new_dir) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
9235                 return -EPERM;
9236
9237         /* we only allow rename subvolume link between subvolumes */
9238         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9239                 return -EXDEV;
9240
9241         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
9242             (new_inode && btrfs_ino(new_inode) == BTRFS_FIRST_FREE_OBJECTID))
9243                 return -ENOTEMPTY;
9244
9245         if (S_ISDIR(old_inode->i_mode) && new_inode &&
9246             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
9247                 return -ENOTEMPTY;
9248
9249
9250         /* check for collisions, even if the  name isn't there */
9251         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
9252                              new_dentry->d_name.name,
9253                              new_dentry->d_name.len);
9254
9255         if (ret) {
9256                 if (ret == -EEXIST) {
9257                         /* we shouldn't get
9258                          * eexist without a new_inode */
9259                         if (WARN_ON(!new_inode)) {
9260                                 return ret;
9261                         }
9262                 } else {
9263                         /* maybe -EOVERFLOW */
9264                         return ret;
9265                 }
9266         }
9267         ret = 0;
9268
9269         /*
9270          * we're using rename to replace one file with another.  Start IO on it
9271          * now so  we don't add too much work to the end of the transaction
9272          */
9273         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
9274                 filemap_flush(old_inode->i_mapping);
9275
9276         /* close the racy window with snapshot create/destroy ioctl */
9277         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9278                 down_read(&root->fs_info->subvol_sem);
9279         /*
9280          * We want to reserve the absolute worst case amount of items.  So if
9281          * both inodes are subvols and we need to unlink them then that would
9282          * require 4 item modifications, but if they are both normal inodes it
9283          * would require 5 item modifications, so we'll assume their normal
9284          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
9285          * should cover the worst case number of items we'll modify.
9286          */
9287         trans = btrfs_start_transaction(root, 11);
9288         if (IS_ERR(trans)) {
9289                 ret = PTR_ERR(trans);
9290                 goto out_notrans;
9291         }
9292
9293         if (dest != root)
9294                 btrfs_record_root_in_trans(trans, dest);
9295
9296         ret = btrfs_set_inode_index(new_dir, &index);
9297         if (ret)
9298                 goto out_fail;
9299
9300         BTRFS_I(old_inode)->dir_index = 0ULL;
9301         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9302                 /* force full log commit if subvolume involved. */
9303                 btrfs_set_log_full_commit(root->fs_info, trans);
9304         } else {
9305                 ret = btrfs_insert_inode_ref(trans, dest,
9306                                              new_dentry->d_name.name,
9307                                              new_dentry->d_name.len,
9308                                              old_ino,
9309                                              btrfs_ino(new_dir), index);
9310                 if (ret)
9311                         goto out_fail;
9312                 /*
9313                  * this is an ugly little race, but the rename is required
9314                  * to make sure that if we crash, the inode is either at the
9315                  * old name or the new one.  pinning the log transaction lets
9316                  * us make sure we don't allow a log commit to come in after
9317                  * we unlink the name but before we add the new name back in.
9318                  */
9319                 btrfs_pin_log_trans(root);
9320         }
9321
9322         inode_inc_iversion(old_dir);
9323         inode_inc_iversion(new_dir);
9324         inode_inc_iversion(old_inode);
9325         old_dir->i_ctime = old_dir->i_mtime = ctime;
9326         new_dir->i_ctime = new_dir->i_mtime = ctime;
9327         old_inode->i_ctime = ctime;
9328
9329         if (old_dentry->d_parent != new_dentry->d_parent)
9330                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
9331
9332         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9333                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9334                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
9335                                         old_dentry->d_name.name,
9336                                         old_dentry->d_name.len);
9337         } else {
9338                 ret = __btrfs_unlink_inode(trans, root, old_dir,
9339                                         d_inode(old_dentry),
9340                                         old_dentry->d_name.name,
9341                                         old_dentry->d_name.len);
9342                 if (!ret)
9343                         ret = btrfs_update_inode(trans, root, old_inode);
9344         }
9345         if (ret) {
9346                 btrfs_abort_transaction(trans, root, ret);
9347                 goto out_fail;
9348         }
9349
9350         if (new_inode) {
9351                 inode_inc_iversion(new_inode);
9352                 new_inode->i_ctime = CURRENT_TIME;
9353                 if (unlikely(btrfs_ino(new_inode) ==
9354                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
9355                         root_objectid = BTRFS_I(new_inode)->location.objectid;
9356                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
9357                                                 root_objectid,
9358                                                 new_dentry->d_name.name,
9359                                                 new_dentry->d_name.len);
9360                         BUG_ON(new_inode->i_nlink == 0);
9361                 } else {
9362                         ret = btrfs_unlink_inode(trans, dest, new_dir,
9363                                                  d_inode(new_dentry),
9364                                                  new_dentry->d_name.name,
9365                                                  new_dentry->d_name.len);
9366                 }
9367                 if (!ret && new_inode->i_nlink == 0)
9368                         ret = btrfs_orphan_add(trans, d_inode(new_dentry));
9369                 if (ret) {
9370                         btrfs_abort_transaction(trans, root, ret);
9371                         goto out_fail;
9372                 }
9373         }
9374
9375         ret = btrfs_add_link(trans, new_dir, old_inode,
9376                              new_dentry->d_name.name,
9377                              new_dentry->d_name.len, 0, index);
9378         if (ret) {
9379                 btrfs_abort_transaction(trans, root, ret);
9380                 goto out_fail;
9381         }
9382
9383         if (old_inode->i_nlink == 1)
9384                 BTRFS_I(old_inode)->dir_index = index;
9385
9386         if (old_ino != BTRFS_FIRST_FREE_OBJECTID) {
9387                 struct dentry *parent = new_dentry->d_parent;
9388                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
9389                 btrfs_end_log_trans(root);
9390         }
9391 out_fail:
9392         btrfs_end_transaction(trans, root);
9393 out_notrans:
9394         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9395                 up_read(&root->fs_info->subvol_sem);
9396
9397         return ret;
9398 }
9399
9400 static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
9401                          struct inode *new_dir, struct dentry *new_dentry,
9402                          unsigned int flags)
9403 {
9404         if (flags & ~RENAME_NOREPLACE)
9405                 return -EINVAL;
9406
9407         return btrfs_rename(old_dir, old_dentry, new_dir, new_dentry);
9408 }
9409
9410 static void btrfs_run_delalloc_work(struct btrfs_work *work)
9411 {
9412         struct btrfs_delalloc_work *delalloc_work;
9413         struct inode *inode;
9414
9415         delalloc_work = container_of(work, struct btrfs_delalloc_work,
9416                                      work);
9417         inode = delalloc_work->inode;
9418         if (delalloc_work->wait) {
9419                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
9420         } else {
9421                 filemap_flush(inode->i_mapping);
9422                 if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
9423                              &BTRFS_I(inode)->runtime_flags))
9424                         filemap_flush(inode->i_mapping);
9425         }
9426
9427         if (delalloc_work->delay_iput)
9428                 btrfs_add_delayed_iput(inode);
9429         else
9430                 iput(inode);
9431         complete(&delalloc_work->completion);
9432 }
9433
9434 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
9435                                                     int wait, int delay_iput)
9436 {
9437         struct btrfs_delalloc_work *work;
9438
9439         work = kmem_cache_zalloc(btrfs_delalloc_work_cachep, GFP_NOFS);
9440         if (!work)
9441                 return NULL;
9442
9443         init_completion(&work->completion);
9444         INIT_LIST_HEAD(&work->list);
9445         work->inode = inode;
9446         work->wait = wait;
9447         work->delay_iput = delay_iput;
9448         WARN_ON_ONCE(!inode);
9449         btrfs_init_work(&work->work, btrfs_flush_delalloc_helper,
9450                         btrfs_run_delalloc_work, NULL, NULL);
9451
9452         return work;
9453 }
9454
9455 void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
9456 {
9457         wait_for_completion(&work->completion);
9458         kmem_cache_free(btrfs_delalloc_work_cachep, work);
9459 }
9460
9461 /*
9462  * some fairly slow code that needs optimization. This walks the list
9463  * of all the inodes with pending delalloc and forces them to disk.
9464  */
9465 static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
9466                                    int nr)
9467 {
9468         struct btrfs_inode *binode;
9469         struct inode *inode;
9470         struct btrfs_delalloc_work *work, *next;
9471         struct list_head works;
9472         struct list_head splice;
9473         int ret = 0;
9474
9475         INIT_LIST_HEAD(&works);
9476         INIT_LIST_HEAD(&splice);
9477
9478         mutex_lock(&root->delalloc_mutex);
9479         spin_lock(&root->delalloc_lock);
9480         list_splice_init(&root->delalloc_inodes, &splice);
9481         while (!list_empty(&splice)) {
9482                 binode = list_entry(splice.next, struct btrfs_inode,
9483                                     delalloc_inodes);
9484
9485                 list_move_tail(&binode->delalloc_inodes,
9486                                &root->delalloc_inodes);
9487                 inode = igrab(&binode->vfs_inode);
9488                 if (!inode) {
9489                         cond_resched_lock(&root->delalloc_lock);
9490                         continue;
9491                 }
9492                 spin_unlock(&root->delalloc_lock);
9493
9494                 work = btrfs_alloc_delalloc_work(inode, 0, delay_iput);
9495                 if (!work) {
9496                         if (delay_iput)
9497                                 btrfs_add_delayed_iput(inode);
9498                         else
9499                                 iput(inode);
9500                         ret = -ENOMEM;
9501                         goto out;
9502                 }
9503                 list_add_tail(&work->list, &works);
9504                 btrfs_queue_work(root->fs_info->flush_workers,
9505                                  &work->work);
9506                 ret++;
9507                 if (nr != -1 && ret >= nr)
9508                         goto out;
9509                 cond_resched();
9510                 spin_lock(&root->delalloc_lock);
9511         }
9512         spin_unlock(&root->delalloc_lock);
9513
9514 out:
9515         list_for_each_entry_safe(work, next, &works, list) {
9516                 list_del_init(&work->list);
9517                 btrfs_wait_and_free_delalloc_work(work);
9518         }
9519
9520         if (!list_empty_careful(&splice)) {
9521                 spin_lock(&root->delalloc_lock);
9522                 list_splice_tail(&splice, &root->delalloc_inodes);
9523                 spin_unlock(&root->delalloc_lock);
9524         }
9525         mutex_unlock(&root->delalloc_mutex);
9526         return ret;
9527 }
9528
9529 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
9530 {
9531         int ret;
9532
9533         if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
9534                 return -EROFS;
9535
9536         ret = __start_delalloc_inodes(root, delay_iput, -1);
9537         if (ret > 0)
9538                 ret = 0;
9539         /*
9540          * the filemap_flush will queue IO into the worker threads, but
9541          * we have to make sure the IO is actually started and that
9542          * ordered extents get created before we return
9543          */
9544         atomic_inc(&root->fs_info->async_submit_draining);
9545         while (atomic_read(&root->fs_info->nr_async_submits) ||
9546               atomic_read(&root->fs_info->async_delalloc_pages)) {
9547                 wait_event(root->fs_info->async_submit_wait,
9548                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
9549                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
9550         }
9551         atomic_dec(&root->fs_info->async_submit_draining);
9552         return ret;
9553 }
9554
9555 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
9556                                int nr)
9557 {
9558         struct btrfs_root *root;
9559         struct list_head splice;
9560         int ret;
9561
9562         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
9563                 return -EROFS;
9564
9565         INIT_LIST_HEAD(&splice);
9566
9567         mutex_lock(&fs_info->delalloc_root_mutex);
9568         spin_lock(&fs_info->delalloc_root_lock);
9569         list_splice_init(&fs_info->delalloc_roots, &splice);
9570         while (!list_empty(&splice) && nr) {
9571                 root = list_first_entry(&splice, struct btrfs_root,
9572                                         delalloc_root);
9573                 root = btrfs_grab_fs_root(root);
9574                 BUG_ON(!root);
9575                 list_move_tail(&root->delalloc_root,
9576                                &fs_info->delalloc_roots);
9577                 spin_unlock(&fs_info->delalloc_root_lock);
9578
9579                 ret = __start_delalloc_inodes(root, delay_iput, nr);
9580                 btrfs_put_fs_root(root);
9581                 if (ret < 0)
9582                         goto out;
9583
9584                 if (nr != -1) {
9585                         nr -= ret;
9586                         WARN_ON(nr < 0);
9587                 }
9588                 spin_lock(&fs_info->delalloc_root_lock);
9589         }
9590         spin_unlock(&fs_info->delalloc_root_lock);
9591
9592         ret = 0;
9593         atomic_inc(&fs_info->async_submit_draining);
9594         while (atomic_read(&fs_info->nr_async_submits) ||
9595               atomic_read(&fs_info->async_delalloc_pages)) {
9596                 wait_event(fs_info->async_submit_wait,
9597                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
9598                     atomic_read(&fs_info->async_delalloc_pages) == 0));
9599         }
9600         atomic_dec(&fs_info->async_submit_draining);
9601 out:
9602         if (!list_empty_careful(&splice)) {
9603                 spin_lock(&fs_info->delalloc_root_lock);
9604                 list_splice_tail(&splice, &fs_info->delalloc_roots);
9605                 spin_unlock(&fs_info->delalloc_root_lock);
9606         }
9607         mutex_unlock(&fs_info->delalloc_root_mutex);
9608         return ret;
9609 }
9610
9611 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
9612                          const char *symname)
9613 {
9614         struct btrfs_trans_handle *trans;
9615         struct btrfs_root *root = BTRFS_I(dir)->root;
9616         struct btrfs_path *path;
9617         struct btrfs_key key;
9618         struct inode *inode = NULL;
9619         int err;
9620         int drop_inode = 0;
9621         u64 objectid;
9622         u64 index = 0;
9623         int name_len;
9624         int datasize;
9625         unsigned long ptr;
9626         struct btrfs_file_extent_item *ei;
9627         struct extent_buffer *leaf;
9628
9629         name_len = strlen(symname);
9630         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
9631                 return -ENAMETOOLONG;
9632
9633         /*
9634          * 2 items for inode item and ref
9635          * 2 items for dir items
9636          * 1 item for xattr if selinux is on
9637          */
9638         trans = btrfs_start_transaction(root, 5);
9639         if (IS_ERR(trans))
9640                 return PTR_ERR(trans);
9641
9642         err = btrfs_find_free_ino(root, &objectid);
9643         if (err)
9644                 goto out_unlock;
9645
9646         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
9647                                 dentry->d_name.len, btrfs_ino(dir), objectid,
9648                                 S_IFLNK|S_IRWXUGO, &index);
9649         if (IS_ERR(inode)) {
9650                 err = PTR_ERR(inode);
9651                 goto out_unlock;
9652         }
9653
9654         /*
9655         * If the active LSM wants to access the inode during
9656         * d_instantiate it needs these. Smack checks to see
9657         * if the filesystem supports xattrs by looking at the
9658         * ops vector.
9659         */
9660         inode->i_fop = &btrfs_file_operations;
9661         inode->i_op = &btrfs_file_inode_operations;
9662         inode->i_mapping->a_ops = &btrfs_aops;
9663         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
9664
9665         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
9666         if (err)
9667                 goto out_unlock_inode;
9668
9669         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
9670         if (err)
9671                 goto out_unlock_inode;
9672
9673         path = btrfs_alloc_path();
9674         if (!path) {
9675                 err = -ENOMEM;
9676                 goto out_unlock_inode;
9677         }
9678         key.objectid = btrfs_ino(inode);
9679         key.offset = 0;
9680         key.type = BTRFS_EXTENT_DATA_KEY;
9681         datasize = btrfs_file_extent_calc_inline_size(name_len);
9682         err = btrfs_insert_empty_item(trans, root, path, &key,
9683                                       datasize);
9684         if (err) {
9685                 btrfs_free_path(path);
9686                 goto out_unlock_inode;
9687         }
9688         leaf = path->nodes[0];
9689         ei = btrfs_item_ptr(leaf, path->slots[0],
9690                             struct btrfs_file_extent_item);
9691         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
9692         btrfs_set_file_extent_type(leaf, ei,
9693                                    BTRFS_FILE_EXTENT_INLINE);
9694         btrfs_set_file_extent_encryption(leaf, ei, 0);
9695         btrfs_set_file_extent_compression(leaf, ei, 0);
9696         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
9697         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
9698
9699         ptr = btrfs_file_extent_inline_start(ei);
9700         write_extent_buffer(leaf, symname, ptr, name_len);
9701         btrfs_mark_buffer_dirty(leaf);
9702         btrfs_free_path(path);
9703
9704         inode->i_op = &btrfs_symlink_inode_operations;
9705         inode->i_mapping->a_ops = &btrfs_symlink_aops;
9706         inode_set_bytes(inode, name_len);
9707         btrfs_i_size_write(inode, name_len);
9708         err = btrfs_update_inode(trans, root, inode);
9709         if (err) {
9710                 drop_inode = 1;
9711                 goto out_unlock_inode;
9712         }
9713
9714         unlock_new_inode(inode);
9715         d_instantiate(dentry, inode);
9716
9717 out_unlock:
9718         btrfs_end_transaction(trans, root);
9719         if (drop_inode) {
9720                 inode_dec_link_count(inode);
9721                 iput(inode);
9722         }
9723         btrfs_btree_balance_dirty(root);
9724         return err;
9725
9726 out_unlock_inode:
9727         drop_inode = 1;
9728         unlock_new_inode(inode);
9729         goto out_unlock;
9730 }
9731
9732 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
9733                                        u64 start, u64 num_bytes, u64 min_size,
9734                                        loff_t actual_len, u64 *alloc_hint,
9735                                        struct btrfs_trans_handle *trans)
9736 {
9737         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
9738         struct extent_map *em;
9739         struct btrfs_root *root = BTRFS_I(inode)->root;
9740         struct btrfs_key ins;
9741         u64 cur_offset = start;
9742         u64 i_size;
9743         u64 cur_bytes;
9744         u64 last_alloc = (u64)-1;
9745         int ret = 0;
9746         bool own_trans = true;
9747
9748         if (trans)
9749                 own_trans = false;
9750         while (num_bytes > 0) {
9751                 if (own_trans) {
9752                         trans = btrfs_start_transaction(root, 3);
9753                         if (IS_ERR(trans)) {
9754                                 ret = PTR_ERR(trans);
9755                                 break;
9756                         }
9757                 }
9758
9759                 cur_bytes = min(num_bytes, 256ULL * 1024 * 1024);
9760                 cur_bytes = max(cur_bytes, min_size);
9761                 /*
9762                  * If we are severely fragmented we could end up with really
9763                  * small allocations, so if the allocator is returning small
9764                  * chunks lets make its job easier by only searching for those
9765                  * sized chunks.
9766                  */
9767                 cur_bytes = min(cur_bytes, last_alloc);
9768                 ret = btrfs_reserve_extent(root, cur_bytes, min_size, 0,
9769                                            *alloc_hint, &ins, 1, 0);
9770                 if (ret) {
9771                         if (own_trans)
9772                                 btrfs_end_transaction(trans, root);
9773                         break;
9774                 }
9775
9776                 last_alloc = ins.offset;
9777                 ret = insert_reserved_file_extent(trans, inode,
9778                                                   cur_offset, ins.objectid,
9779                                                   ins.offset, ins.offset,
9780                                                   ins.offset, 0, 0, 0,
9781                                                   BTRFS_FILE_EXTENT_PREALLOC);
9782                 if (ret) {
9783                         btrfs_free_reserved_extent(root, ins.objectid,
9784                                                    ins.offset, 0);
9785                         btrfs_abort_transaction(trans, root, ret);
9786                         if (own_trans)
9787                                 btrfs_end_transaction(trans, root);
9788                         break;
9789                 }
9790
9791                 btrfs_drop_extent_cache(inode, cur_offset,
9792                                         cur_offset + ins.offset -1, 0);
9793
9794                 em = alloc_extent_map();
9795                 if (!em) {
9796                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
9797                                 &BTRFS_I(inode)->runtime_flags);
9798                         goto next;
9799                 }
9800
9801                 em->start = cur_offset;
9802                 em->orig_start = cur_offset;
9803                 em->len = ins.offset;
9804                 em->block_start = ins.objectid;
9805                 em->block_len = ins.offset;
9806                 em->orig_block_len = ins.offset;
9807                 em->ram_bytes = ins.offset;
9808                 em->bdev = root->fs_info->fs_devices->latest_bdev;
9809                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
9810                 em->generation = trans->transid;
9811
9812                 while (1) {
9813                         write_lock(&em_tree->lock);
9814                         ret = add_extent_mapping(em_tree, em, 1);
9815                         write_unlock(&em_tree->lock);
9816                         if (ret != -EEXIST)
9817                                 break;
9818                         btrfs_drop_extent_cache(inode, cur_offset,
9819                                                 cur_offset + ins.offset - 1,
9820                                                 0);
9821                 }
9822                 free_extent_map(em);
9823 next:
9824                 num_bytes -= ins.offset;
9825                 cur_offset += ins.offset;
9826                 *alloc_hint = ins.objectid + ins.offset;
9827
9828                 inode_inc_iversion(inode);
9829                 inode->i_ctime = CURRENT_TIME;
9830                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
9831                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
9832                     (actual_len > inode->i_size) &&
9833                     (cur_offset > inode->i_size)) {
9834                         if (cur_offset > actual_len)
9835                                 i_size = actual_len;
9836                         else
9837                                 i_size = cur_offset;
9838                         i_size_write(inode, i_size);
9839                         btrfs_ordered_update_i_size(inode, i_size, NULL);
9840                 }
9841
9842                 ret = btrfs_update_inode(trans, root, inode);
9843
9844                 if (ret) {
9845                         btrfs_abort_transaction(trans, root, ret);
9846                         if (own_trans)
9847                                 btrfs_end_transaction(trans, root);
9848                         break;
9849                 }
9850
9851                 if (own_trans)
9852                         btrfs_end_transaction(trans, root);
9853         }
9854         return ret;
9855 }
9856
9857 int btrfs_prealloc_file_range(struct inode *inode, int mode,
9858                               u64 start, u64 num_bytes, u64 min_size,
9859                               loff_t actual_len, u64 *alloc_hint)
9860 {
9861         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
9862                                            min_size, actual_len, alloc_hint,
9863                                            NULL);
9864 }
9865
9866 int btrfs_prealloc_file_range_trans(struct inode *inode,
9867                                     struct btrfs_trans_handle *trans, int mode,
9868                                     u64 start, u64 num_bytes, u64 min_size,
9869                                     loff_t actual_len, u64 *alloc_hint)
9870 {
9871         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
9872                                            min_size, actual_len, alloc_hint, trans);
9873 }
9874
9875 static int btrfs_set_page_dirty(struct page *page)
9876 {
9877         return __set_page_dirty_nobuffers(page);
9878 }
9879
9880 static int btrfs_permission(struct inode *inode, int mask)
9881 {
9882         struct btrfs_root *root = BTRFS_I(inode)->root;
9883         umode_t mode = inode->i_mode;
9884
9885         if (mask & MAY_WRITE &&
9886             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
9887                 if (btrfs_root_readonly(root))
9888                         return -EROFS;
9889                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
9890                         return -EACCES;
9891         }
9892         return generic_permission(inode, mask);
9893 }
9894
9895 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
9896 {
9897         struct btrfs_trans_handle *trans;
9898         struct btrfs_root *root = BTRFS_I(dir)->root;
9899         struct inode *inode = NULL;
9900         u64 objectid;
9901         u64 index;
9902         int ret = 0;
9903
9904         /*
9905          * 5 units required for adding orphan entry
9906          */
9907         trans = btrfs_start_transaction(root, 5);
9908         if (IS_ERR(trans))
9909                 return PTR_ERR(trans);
9910
9911         ret = btrfs_find_free_ino(root, &objectid);
9912         if (ret)
9913                 goto out;
9914
9915         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
9916                                 btrfs_ino(dir), objectid, mode, &index);
9917         if (IS_ERR(inode)) {
9918                 ret = PTR_ERR(inode);
9919                 inode = NULL;
9920                 goto out;
9921         }
9922
9923         inode->i_fop = &btrfs_file_operations;
9924         inode->i_op = &btrfs_file_inode_operations;
9925
9926         inode->i_mapping->a_ops = &btrfs_aops;
9927         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
9928
9929         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
9930         if (ret)
9931                 goto out_inode;
9932
9933         ret = btrfs_update_inode(trans, root, inode);
9934         if (ret)
9935                 goto out_inode;
9936         ret = btrfs_orphan_add(trans, inode);
9937         if (ret)
9938                 goto out_inode;
9939
9940         /*
9941          * We set number of links to 0 in btrfs_new_inode(), and here we set
9942          * it to 1 because d_tmpfile() will issue a warning if the count is 0,
9943          * through:
9944          *
9945          *    d_tmpfile() -> inode_dec_link_count() -> drop_nlink()
9946          */
9947         set_nlink(inode, 1);
9948         unlock_new_inode(inode);
9949         d_tmpfile(dentry, inode);
9950         mark_inode_dirty(inode);
9951
9952 out:
9953         btrfs_end_transaction(trans, root);
9954         if (ret)
9955                 iput(inode);
9956         btrfs_balance_delayed_items(root);
9957         btrfs_btree_balance_dirty(root);
9958         return ret;
9959
9960 out_inode:
9961         unlock_new_inode(inode);
9962         goto out;
9963
9964 }
9965
9966 /* Inspired by filemap_check_errors() */
9967 int btrfs_inode_check_errors(struct inode *inode)
9968 {
9969         int ret = 0;
9970
9971         if (test_bit(AS_ENOSPC, &inode->i_mapping->flags) &&
9972             test_and_clear_bit(AS_ENOSPC, &inode->i_mapping->flags))
9973                 ret = -ENOSPC;
9974         if (test_bit(AS_EIO, &inode->i_mapping->flags) &&
9975             test_and_clear_bit(AS_EIO, &inode->i_mapping->flags))
9976                 ret = -EIO;
9977
9978         return ret;
9979 }
9980
9981 static const struct inode_operations btrfs_dir_inode_operations = {
9982         .getattr        = btrfs_getattr,
9983         .lookup         = btrfs_lookup,
9984         .create         = btrfs_create,
9985         .unlink         = btrfs_unlink,
9986         .link           = btrfs_link,
9987         .mkdir          = btrfs_mkdir,
9988         .rmdir          = btrfs_rmdir,
9989         .rename2        = btrfs_rename2,
9990         .symlink        = btrfs_symlink,
9991         .setattr        = btrfs_setattr,
9992         .mknod          = btrfs_mknod,
9993         .setxattr       = btrfs_setxattr,
9994         .getxattr       = btrfs_getxattr,
9995         .listxattr      = btrfs_listxattr,
9996         .removexattr    = btrfs_removexattr,
9997         .permission     = btrfs_permission,
9998         .get_acl        = btrfs_get_acl,
9999         .set_acl        = btrfs_set_acl,
10000         .update_time    = btrfs_update_time,
10001         .tmpfile        = btrfs_tmpfile,
10002 };
10003 static const struct inode_operations btrfs_dir_ro_inode_operations = {
10004         .lookup         = btrfs_lookup,
10005         .permission     = btrfs_permission,
10006         .get_acl        = btrfs_get_acl,
10007         .set_acl        = btrfs_set_acl,
10008         .update_time    = btrfs_update_time,
10009 };
10010
10011 static const struct file_operations btrfs_dir_file_operations = {
10012         .llseek         = generic_file_llseek,
10013         .read           = generic_read_dir,
10014         .iterate        = btrfs_real_readdir,
10015         .unlocked_ioctl = btrfs_ioctl,
10016 #ifdef CONFIG_COMPAT
10017         .compat_ioctl   = btrfs_ioctl,
10018 #endif
10019         .release        = btrfs_release_file,
10020         .fsync          = btrfs_sync_file,
10021 };
10022
10023 static struct extent_io_ops btrfs_extent_io_ops = {
10024         .fill_delalloc = run_delalloc_range,
10025         .submit_bio_hook = btrfs_submit_bio_hook,
10026         .merge_bio_hook = btrfs_merge_bio_hook,
10027         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
10028         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
10029         .writepage_start_hook = btrfs_writepage_start_hook,
10030         .set_bit_hook = btrfs_set_bit_hook,
10031         .clear_bit_hook = btrfs_clear_bit_hook,
10032         .merge_extent_hook = btrfs_merge_extent_hook,
10033         .split_extent_hook = btrfs_split_extent_hook,
10034 };
10035
10036 /*
10037  * btrfs doesn't support the bmap operation because swapfiles
10038  * use bmap to make a mapping of extents in the file.  They assume
10039  * these extents won't change over the life of the file and they
10040  * use the bmap result to do IO directly to the drive.
10041  *
10042  * the btrfs bmap call would return logical addresses that aren't
10043  * suitable for IO and they also will change frequently as COW
10044  * operations happen.  So, swapfile + btrfs == corruption.
10045  *
10046  * For now we're avoiding this by dropping bmap.
10047  */
10048 static const struct address_space_operations btrfs_aops = {
10049         .readpage       = btrfs_readpage,
10050         .writepage      = btrfs_writepage,
10051         .writepages     = btrfs_writepages,
10052         .readpages      = btrfs_readpages,
10053         .direct_IO      = btrfs_direct_IO,
10054         .invalidatepage = btrfs_invalidatepage,
10055         .releasepage    = btrfs_releasepage,
10056         .set_page_dirty = btrfs_set_page_dirty,
10057         .error_remove_page = generic_error_remove_page,
10058 };
10059
10060 static const struct address_space_operations btrfs_symlink_aops = {
10061         .readpage       = btrfs_readpage,
10062         .writepage      = btrfs_writepage,
10063         .invalidatepage = btrfs_invalidatepage,
10064         .releasepage    = btrfs_releasepage,
10065 };
10066
10067 static const struct inode_operations btrfs_file_inode_operations = {
10068         .getattr        = btrfs_getattr,
10069         .setattr        = btrfs_setattr,
10070         .setxattr       = btrfs_setxattr,
10071         .getxattr       = btrfs_getxattr,
10072         .listxattr      = btrfs_listxattr,
10073         .removexattr    = btrfs_removexattr,
10074         .permission     = btrfs_permission,
10075         .fiemap         = btrfs_fiemap,
10076         .get_acl        = btrfs_get_acl,
10077         .set_acl        = btrfs_set_acl,
10078         .update_time    = btrfs_update_time,
10079 };
10080 static const struct inode_operations btrfs_special_inode_operations = {
10081         .getattr        = btrfs_getattr,
10082         .setattr        = btrfs_setattr,
10083         .permission     = btrfs_permission,
10084         .setxattr       = btrfs_setxattr,
10085         .getxattr       = btrfs_getxattr,
10086         .listxattr      = btrfs_listxattr,
10087         .removexattr    = btrfs_removexattr,
10088         .get_acl        = btrfs_get_acl,
10089         .set_acl        = btrfs_set_acl,
10090         .update_time    = btrfs_update_time,
10091 };
10092 static const struct inode_operations btrfs_symlink_inode_operations = {
10093         .readlink       = generic_readlink,
10094         .follow_link    = page_follow_link_light,
10095         .put_link       = page_put_link,
10096         .getattr        = btrfs_getattr,
10097         .setattr        = btrfs_setattr,
10098         .permission     = btrfs_permission,
10099         .setxattr       = btrfs_setxattr,
10100         .getxattr       = btrfs_getxattr,
10101         .listxattr      = btrfs_listxattr,
10102         .removexattr    = btrfs_removexattr,
10103         .update_time    = btrfs_update_time,
10104 };
10105
10106 const struct dentry_operations btrfs_dentry_operations = {
10107         .d_delete       = btrfs_dentry_delete,
10108         .d_release      = btrfs_dentry_release,
10109 };