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/aio.h>
  36 #include <linux/bit_spinlock.h>
  37 #include <linux/xattr.h>
  38 #include <linux/posix_acl.h>
  39 #include <linux/falloc.h>
  40 #include <linux/slab.h>
  41 #include <linux/ratelimit.h>
  42 #include <linux/mount.h>
  43 #include <linux/btrfs.h>
  44 #include <linux/blkdev.h>
  45 #include <linux/posix_acl_xattr.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
  62 struct btrfs_iget_args {
  63         u64 ino;
  64         struct btrfs_root *root;
  65 };
  66
  67 static const struct inode_operations btrfs_dir_inode_operations;
  68 static const struct inode_operations btrfs_symlink_inode_operations;
  69 static const struct inode_operations btrfs_dir_ro_inode_operations;
  70 static const struct inode_operations btrfs_special_inode_operations;
  71 static const struct inode_operations btrfs_file_inode_operations;
  72 static const struct address_space_operations btrfs_aops;
  73 static const struct address_space_operations btrfs_symlink_aops;
  74 static const struct file_operations btrfs_dir_file_operations;
  75 static struct extent_io_ops btrfs_extent_io_ops;
  76
  77 static struct kmem_cache *btrfs_inode_cachep;
  78 static struct kmem_cache *btrfs_delalloc_work_cachep;
  79 struct kmem_cache *btrfs_trans_handle_cachep;
  80 struct kmem_cache *btrfs_transaction_cachep;
  81 struct kmem_cache *btrfs_path_cachep;
  82 struct kmem_cache *btrfs_free_space_cachep;
  83
  84 #define S_SHIFT 12
  85 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  86         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  87         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  88         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  89         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  90         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  91         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  92         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  93 };
  94
  95 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
  96 static int btrfs_truncate(struct inode *inode);
  97 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
  98 static noinline int cow_file_range(struct inode *inode,
  99                                    struct page *locked_page,
 100                                    u64 start, u64 end, int *page_started,
 101                                    unsigned long *nr_written, int unlock);
 102 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
 103                                            u64 len, u64 orig_start,
 104                                            u64 block_start, u64 block_len,
 105                                            u64 orig_block_len, u64 ram_bytes,
 106                                            int type);
 107
 108 static int btrfs_dirty_inode(struct inode *inode);
 109
 110 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 111                                      struct inode *inode,  struct inode *dir,
 112                                      const struct qstr *qstr)
 113 {
 114         int err;
 115
 116         err = btrfs_init_acl(trans, inode, dir);
 117         if (!err)
 118                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 119         return err;
 120 }
 121
 122 /*
 123  * this does all the hard work for inserting an inline extent into
 124  * the btree.  The caller should have done a btrfs_drop_extents so that
 125  * no overlapping inline items exist in the btree
 126  */
 127 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
 128                                 struct btrfs_root *root, struct inode *inode,
 129                                 u64 start, size_t size, size_t compressed_size,
 130                                 int compress_type,
 131                                 struct page **compressed_pages)
 132 {
 133         struct btrfs_key key;
 134         struct btrfs_path *path;
 135         struct extent_buffer *leaf;
 136         struct page *page = NULL;
 137         char *kaddr;
 138         unsigned long ptr;
 139         struct btrfs_file_extent_item *ei;
 140         int err = 0;
 141         int ret;
 142         size_t cur_size = size;
 143         size_t datasize;
 144         unsigned long offset;
 145
 146         if (compressed_size && compressed_pages)
 147                 cur_size = compressed_size;
 148
 149         path = btrfs_alloc_path();
 150         if (!path)
 151                 return -ENOMEM;
 152
 153         path->leave_spinning = 1;
 154
 155         key.objectid = btrfs_ino(inode);
 156         key.offset = start;
 157         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
 158         datasize = btrfs_file_extent_calc_inline_size(cur_size);
 159
 160         inode_add_bytes(inode, size);
 161         ret = btrfs_insert_empty_item(trans, root, path, &key,
 162                                       datasize);
 163         if (ret) {
 164                 err = ret;
 165                 goto fail;
 166         }
 167         leaf = path->nodes[0];
 168         ei = btrfs_item_ptr(leaf, path->slots[0],
 169                             struct btrfs_file_extent_item);
 170         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 171         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 172         btrfs_set_file_extent_encryption(leaf, ei, 0);
 173         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 174         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 175         ptr = btrfs_file_extent_inline_start(ei);
 176
 177         if (compress_type != BTRFS_COMPRESS_NONE) {
 178                 struct page *cpage;
 179                 int i = 0;
 180                 while (compressed_size > 0) {
 181                         cpage = compressed_pages[i];
 182                         cur_size = min_t(unsigned long, compressed_size,
 183                                        PAGE_CACHE_SIZE);
 184
 185                         kaddr = kmap_atomic(cpage);
 186                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 187                         kunmap_atomic(kaddr);
 188
 189                         i++;
 190                         ptr += cur_size;
 191                         compressed_size -= cur_size;
 192                 }
 193                 btrfs_set_file_extent_compression(leaf, ei,
 194                                                   compress_type);
 195         } else {
 196                 page = find_get_page(inode->i_mapping,
 197                                      start >> PAGE_CACHE_SHIFT);
 198                 btrfs_set_file_extent_compression(leaf, ei, 0);
 199                 kaddr = kmap_atomic(page);
 200                 offset = start & (PAGE_CACHE_SIZE - 1);
 201                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 202                 kunmap_atomic(kaddr);
 203                 page_cache_release(page);
 204         }
 205         btrfs_mark_buffer_dirty(leaf);
 206         btrfs_free_path(path);
 207
 208         /*
 209          * we're an inline extent, so nobody can
 210          * extend the file past i_size without locking
 211          * a page we already have locked.
 212          *
 213          * We must do any isize and inode updates
 214          * before we unlock the pages.  Otherwise we
 215          * could end up racing with unlink.
 216          */
 217         BTRFS_I(inode)->disk_i_size = inode->i_size;
 218         ret = btrfs_update_inode(trans, root, inode);
 219
 220         return ret;
 221 fail:
 222         btrfs_free_path(path);
 223         return err;
 224 }
 225
 226
 227 /*
 228  * conditionally insert an inline extent into the file.  This
 229  * does the checks required to make sure the data is small enough
 230  * to fit as an inline extent.
 231  */
 232 static noinline int cow_file_range_inline(struct btrfs_root *root,
 233                                           struct inode *inode, u64 start,
 234                                           u64 end, size_t compressed_size,
 235                                           int compress_type,
 236                                           struct page **compressed_pages)
 237 {
 238         struct btrfs_trans_handle *trans;
 239         u64 isize = i_size_read(inode);
 240         u64 actual_end = min(end + 1, isize);
 241         u64 inline_len = actual_end - start;
 242         u64 aligned_end = ALIGN(end, root->sectorsize);
 243         u64 data_len = inline_len;
 244         int ret;
 245
 246         if (compressed_size)
 247                 data_len = compressed_size;
 248
 249         if (start > 0 ||
 250             actual_end >= PAGE_CACHE_SIZE ||
 251             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 252             (!compressed_size &&
 253             (actual_end & (root->sectorsize - 1)) == 0) ||
 254             end + 1 < isize ||
 255             data_len > root->fs_info->max_inline) {
 256                 return 1;
 257         }
 258
 259         trans = btrfs_join_transaction(root);
 260         if (IS_ERR(trans))
 261                 return PTR_ERR(trans);
 262         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 263
 264         ret = btrfs_drop_extents(trans, root, inode, start, aligned_end, 1);
 265         if (ret) {
 266                 btrfs_abort_transaction(trans, root, ret);
 267                 goto out;
 268         }
 269
 270         if (isize > actual_end)
 271                 inline_len = min_t(u64, isize, actual_end);
 272         ret = insert_inline_extent(trans, root, inode, start,
 273                                    inline_len, compressed_size,
 274                                    compress_type, compressed_pages);
 275         if (ret && ret != -ENOSPC) {
 276                 btrfs_abort_transaction(trans, root, ret);
 277                 goto out;
 278         } else if (ret == -ENOSPC) {
 279                 ret = 1;
 280                 goto out;
 281         }
 282
 283         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 284         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 285         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 286 out:
 287         btrfs_end_transaction(trans, root);
 288         return ret;
 289 }
 290
 291 struct async_extent {
 292         u64 start;
 293         u64 ram_size;
 294         u64 compressed_size;
 295         struct page **pages;
 296         unsigned long nr_pages;
 297         int compress_type;
 298         struct list_head list;
 299 };
 300
 301 struct async_cow {
 302         struct inode *inode;
 303         struct btrfs_root *root;
 304         struct page *locked_page;
 305         u64 start;
 306         u64 end;
 307         struct list_head extents;
 308         struct btrfs_work work;
 309 };
 310
 311 static noinline int add_async_extent(struct async_cow *cow,
 312                                      u64 start, u64 ram_size,
 313                                      u64 compressed_size,
 314                                      struct page **pages,
 315                                      unsigned long nr_pages,
 316                                      int compress_type)
 317 {
 318         struct async_extent *async_extent;
 319
 320         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 321         BUG_ON(!async_extent); /* -ENOMEM */
 322         async_extent->start = start;
 323         async_extent->ram_size = ram_size;
 324         async_extent->compressed_size = compressed_size;
 325         async_extent->pages = pages;
 326         async_extent->nr_pages = nr_pages;
 327         async_extent->compress_type = compress_type;
 328         list_add_tail(&async_extent->list, &cow->extents);
 329         return 0;
 330 }
 331
 332 /*
 333  * we create compressed extents in two phases.  The first
 334  * phase compresses a range of pages that have already been
 335  * locked (both pages and state bits are locked).
 336  *
 337  * This is done inside an ordered work queue, and the compression
 338  * is spread across many cpus.  The actual IO submission is step
 339  * two, and the ordered work queue takes care of making sure that
 340  * happens in the same order things were put onto the queue by
 341  * writepages and friends.
 342  *
 343  * If this code finds it can't get good compression, it puts an
 344  * entry onto the work queue to write the uncompressed bytes.  This
 345  * makes sure that both compressed inodes and uncompressed inodes
 346  * are written in the same order that the flusher thread sent them
 347  * down.
 348  */
 349 static noinline int compress_file_range(struct inode *inode,
 350                                         struct page *locked_page,
 351                                         u64 start, u64 end,
 352                                         struct async_cow *async_cow,
 353                                         int *num_added)
 354 {
 355         struct btrfs_root *root = BTRFS_I(inode)->root;
 356         u64 num_bytes;
 357         u64 blocksize = root->sectorsize;
 358         u64 actual_end;
 359         u64 isize = i_size_read(inode);
 360         int ret = 0;
 361         struct page **pages = NULL;
 362         unsigned long nr_pages;
 363         unsigned long nr_pages_ret = 0;
 364         unsigned long total_compressed = 0;
 365         unsigned long total_in = 0;
 366         unsigned long max_compressed = 128 * 1024;
 367         unsigned long max_uncompressed = 128 * 1024;
 368         int i;
 369         int will_compress;
 370         int compress_type = root->fs_info->compress_type;
 371         int redirty = 0;
 372
 373         /* if this is a small write inside eof, kick off a defrag */
 374         if ((end - start + 1) < 16 * 1024 &&
 375             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 376                 btrfs_add_inode_defrag(NULL, inode);
 377
 378         actual_end = min_t(u64, isize, end + 1);
 379 again:
 380         will_compress = 0;
 381         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
 382         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
 383
 384         /*
 385          * we don't want to send crud past the end of i_size through
 386          * compression, that's just a waste of CPU time.  So, if the
 387          * end of the file is before the start of our current
 388          * requested range of bytes, we bail out to the uncompressed
 389          * cleanup code that can deal with all of this.
 390          *
 391          * It isn't really the fastest way to fix things, but this is a
 392          * very uncommon corner.
 393          */
 394         if (actual_end <= start)
 395                 goto cleanup_and_bail_uncompressed;
 396
 397         total_compressed = actual_end - start;
 398
 399         /* we want to make sure that amount of ram required to uncompress
 400          * an extent is reasonable, so we limit the total size in ram
 401          * of a compressed extent to 128k.  This is a crucial number
 402          * because it also controls how easily we can spread reads across
 403          * cpus for decompression.
 404          *
 405          * We also want to make sure the amount of IO required to do
 406          * a random read is reasonably small, so we limit the size of
 407          * a compressed extent to 128k.
 408          */
 409         total_compressed = min(total_compressed, max_uncompressed);
 410         num_bytes = ALIGN(end - start + 1, blocksize);
 411         num_bytes = max(blocksize,  num_bytes);
 412         total_in = 0;
 413         ret = 0;
 414
 415         /*
 416          * we do compression for mount -o compress and when the
 417          * inode has not been flagged as nocompress.  This flag can
 418          * change at any time if we discover bad compression ratios.
 419          */
 420         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
 421             (btrfs_test_opt(root, COMPRESS) ||
 422              (BTRFS_I(inode)->force_compress) ||
 423              (BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))) {
 424                 WARN_ON(pages);
 425                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
 426                 if (!pages) {
 427                         /* just bail out to the uncompressed code */
 428                         goto cont;
 429                 }
 430
 431                 if (BTRFS_I(inode)->force_compress)
 432                         compress_type = BTRFS_I(inode)->force_compress;
 433
 434                 /*
 435                  * we need to call clear_page_dirty_for_io on each
 436                  * page in the range.  Otherwise applications with the file
 437                  * mmap'd can wander in and change the page contents while
 438                  * we are compressing them.
 439                  *
 440                  * If the compression fails for any reason, we set the pages
 441                  * dirty again later on.
 442                  */
 443                 extent_range_clear_dirty_for_io(inode, start, end);
 444                 redirty = 1;
 445                 ret = btrfs_compress_pages(compress_type,
 446                                            inode->i_mapping, start,
 447                                            total_compressed, pages,
 448                                            nr_pages, &nr_pages_ret,
 449                                            &total_in,
 450                                            &total_compressed,
 451                                            max_compressed);
 452
 453                 if (!ret) {
 454                         unsigned long offset = total_compressed &
 455                                 (PAGE_CACHE_SIZE - 1);
 456                         struct page *page = pages[nr_pages_ret - 1];
 457                         char *kaddr;
 458
 459                         /* zero the tail end of the last page, we might be
 460                          * sending it down to disk
 461                          */
 462                         if (offset) {
 463                                 kaddr = kmap_atomic(page);
 464                                 memset(kaddr + offset, 0,
 465                                        PAGE_CACHE_SIZE - offset);
 466                                 kunmap_atomic(kaddr);
 467                         }
 468                         will_compress = 1;
 469                 }
 470         }
 471 cont:
 472         if (start == 0) {
 473                 /* lets try to make an inline extent */
 474                 if (ret || total_in < (actual_end - start)) {
 475                         /* we didn't compress the entire range, try
 476                          * to make an uncompressed inline extent.
 477                          */
 478                         ret = cow_file_range_inline(root, inode, start, end,
 479                                                     0, 0, NULL);
 480                 } else {
 481                         /* try making a compressed inline extent */
 482                         ret = cow_file_range_inline(root, inode, start, end,
 483                                                     total_compressed,
 484                                                     compress_type, pages);
 485                 }
 486                 if (ret <= 0) {
 487                         unsigned long clear_flags = EXTENT_DELALLOC |
 488                                 EXTENT_DEFRAG;
 489                         clear_flags |= (ret < 0) ? EXTENT_DO_ACCOUNTING : 0;
 490
 491                         /*
 492                          * inline extent creation worked or returned error,
 493                          * we don't need to create any more async work items.
 494                          * Unlock and free up our temp pages.
 495                          */
 496                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 497                                                      clear_flags, PAGE_UNLOCK |
 498                                                      PAGE_CLEAR_DIRTY |
 499                                                      PAGE_SET_WRITEBACK |
 500                                                      PAGE_END_WRITEBACK);
 501                         goto free_pages_out;
 502                 }
 503         }
 504
 505         if (will_compress) {
 506                 /*
 507                  * we aren't doing an inline extent round the compressed size
 508                  * up to a block size boundary so the allocator does sane
 509                  * things
 510                  */
 511                 total_compressed = ALIGN(total_compressed, blocksize);
 512
 513                 /*
 514                  * one last check to make sure the compression is really a
 515                  * win, compare the page count read with the blocks on disk
 516                  */
 517                 total_in = ALIGN(total_in, PAGE_CACHE_SIZE);
 518                 if (total_compressed >= total_in) {
 519                         will_compress = 0;
 520                 } else {
 521                         num_bytes = total_in;
 522                 }
 523         }
 524         if (!will_compress && pages) {
 525                 /*
 526                  * the compression code ran but failed to make things smaller,
 527                  * free any pages it allocated and our page pointer array
 528                  */
 529                 for (i = 0; i < nr_pages_ret; i++) {
 530                         WARN_ON(pages[i]->mapping);
 531                         page_cache_release(pages[i]);
 532                 }
 533                 kfree(pages);
 534                 pages = NULL;
 535                 total_compressed = 0;
 536                 nr_pages_ret = 0;
 537
 538                 /* flag the file so we don't compress in the future */
 539                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
 540                     !(BTRFS_I(inode)->force_compress)) {
 541                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 542                 }
 543         }
 544         if (will_compress) {
 545                 *num_added += 1;
 546
 547                 /* the async work queues will take care of doing actual
 548                  * allocation on disk for these compressed pages,
 549                  * and will submit them to the elevator.
 550                  */
 551                 add_async_extent(async_cow, start, num_bytes,
 552                                  total_compressed, pages, nr_pages_ret,
 553                                  compress_type);
 554
 555                 if (start + num_bytes < end) {
 556                         start += num_bytes;
 557                         pages = NULL;
 558                         cond_resched();
 559                         goto again;
 560                 }
 561         } else {
 562 cleanup_and_bail_uncompressed:
 563                 /*
 564                  * No compression, but we still need to write the pages in
 565                  * the file we've been given so far.  redirty the locked
 566                  * page if it corresponds to our extent and set things up
 567                  * for the async work queue to run cow_file_range to do
 568                  * the normal delalloc dance
 569                  */
 570                 if (page_offset(locked_page) >= start &&
 571                     page_offset(locked_page) <= end) {
 572                         __set_page_dirty_nobuffers(locked_page);
 573                         /* unlocked later on in the async handlers */
 574                 }
 575                 if (redirty)
 576                         extent_range_redirty_for_io(inode, start, end);
 577                 add_async_extent(async_cow, start, end - start + 1,
 578                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
 579                 *num_added += 1;
 580         }
 581
 582 out:
 583         return ret;
 584
 585 free_pages_out:
 586         for (i = 0; i < nr_pages_ret; i++) {
 587                 WARN_ON(pages[i]->mapping);
 588                 page_cache_release(pages[i]);
 589         }
 590         kfree(pages);
 591
 592         goto out;
 593 }
 594
 595 /*
 596  * phase two of compressed writeback.  This is the ordered portion
 597  * of the code, which only gets called in the order the work was
 598  * queued.  We walk all the async extents created by compress_file_range
 599  * and send them down to the disk.
 600  */
 601 static noinline int submit_compressed_extents(struct inode *inode,
 602                                               struct async_cow *async_cow)
 603 {
 604         struct async_extent *async_extent;
 605         u64 alloc_hint = 0;
 606         struct btrfs_key ins;
 607         struct extent_map *em;
 608         struct btrfs_root *root = BTRFS_I(inode)->root;
 609         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 610         struct extent_io_tree *io_tree;
 611         int ret = 0;
 612
 613         if (list_empty(&async_cow->extents))
 614                 return 0;
 615
 616 again:
 617         while (!list_empty(&async_cow->extents)) {
 618                 async_extent = list_entry(async_cow->extents.next,
 619                                           struct async_extent, list);
 620                 list_del(&async_extent->list);
 621
 622                 io_tree = &BTRFS_I(inode)->io_tree;
 623
 624 retry:
 625                 /* did the compression code fall back to uncompressed IO? */
 626                 if (!async_extent->pages) {
 627                         int page_started = 0;
 628                         unsigned long nr_written = 0;
 629
 630                         lock_extent(io_tree, async_extent->start,
 631                                          async_extent->start +
 632                                          async_extent->ram_size - 1);
 633
 634                         /* allocate blocks */
 635                         ret = cow_file_range(inode, async_cow->locked_page,
 636                                              async_extent->start,
 637                                              async_extent->start +
 638                                              async_extent->ram_size - 1,
 639                                              &page_started, &nr_written, 0);
 640
 641                         /* JDM XXX */
 642
 643                         /*
 644                          * if page_started, cow_file_range inserted an
 645                          * inline extent and took care of all the unlocking
 646                          * and IO for us.  Otherwise, we need to submit
 647                          * all those pages down to the drive.
 648                          */
 649                         if (!page_started && !ret)
 650                                 extent_write_locked_range(io_tree,
 651                                                   inode, async_extent->start,
 652                                                   async_extent->start +
 653                                                   async_extent->ram_size - 1,
 654                                                   btrfs_get_extent,
 655                                                   WB_SYNC_ALL);
 656                         else if (ret)
 657                                 unlock_page(async_cow->locked_page);
 658                         kfree(async_extent);
 659                         cond_resched();
 660                         continue;
 661                 }
 662
 663                 lock_extent(io_tree, async_extent->start,
 664                             async_extent->start + async_extent->ram_size - 1);
 665
 666                 ret = btrfs_reserve_extent(root,
 667                                            async_extent->compressed_size,
 668                                            async_extent->compressed_size,
 669                                            0, alloc_hint, &ins, 1);
 670                 if (ret) {
 671                         int i;
 672
 673                         for (i = 0; i < async_extent->nr_pages; i++) {
 674                                 WARN_ON(async_extent->pages[i]->mapping);
 675                                 page_cache_release(async_extent->pages[i]);
 676                         }
 677                         kfree(async_extent->pages);
 678                         async_extent->nr_pages = 0;
 679                         async_extent->pages = NULL;
 680
 681                         if (ret == -ENOSPC) {
 682                                 unlock_extent(io_tree, async_extent->start,
 683                                               async_extent->start +
 684                                               async_extent->ram_size - 1);
 685                                 goto retry;
 686                         }
 687                         goto out_free;
 688                 }
 689
 690                 /*
 691                  * here we're doing allocation and writeback of the
 692                  * compressed pages
 693                  */
 694                 btrfs_drop_extent_cache(inode, async_extent->start,
 695                                         async_extent->start +
 696                                         async_extent->ram_size - 1, 0);
 697
 698                 em = alloc_extent_map();
 699                 if (!em) {
 700                         ret = -ENOMEM;
 701                         goto out_free_reserve;
 702                 }
 703                 em->start = async_extent->start;
 704                 em->len = async_extent->ram_size;
 705                 em->orig_start = em->start;
 706                 em->mod_start = em->start;
 707                 em->mod_len = em->len;
 708
 709                 em->block_start = ins.objectid;
 710                 em->block_len = ins.offset;
 711                 em->orig_block_len = ins.offset;
 712                 em->ram_bytes = async_extent->ram_size;
 713                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 714                 em->compress_type = async_extent->compress_type;
 715                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 716                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 717                 em->generation = -1;
 718
 719                 while (1) {
 720                         write_lock(&em_tree->lock);
 721                         ret = add_extent_mapping(em_tree, em, 1);
 722                         write_unlock(&em_tree->lock);
 723                         if (ret != -EEXIST) {
 724                                 free_extent_map(em);
 725                                 break;
 726                         }
 727                         btrfs_drop_extent_cache(inode, async_extent->start,
 728                                                 async_extent->start +
 729                                                 async_extent->ram_size - 1, 0);
 730                 }
 731
 732                 if (ret)
 733                         goto out_free_reserve;
 734
 735                 ret = btrfs_add_ordered_extent_compress(inode,
 736                                                 async_extent->start,
 737                                                 ins.objectid,
 738                                                 async_extent->ram_size,
 739                                                 ins.offset,
 740                                                 BTRFS_ORDERED_COMPRESSED,
 741                                                 async_extent->compress_type);
 742                 if (ret)
 743                         goto out_free_reserve;
 744
 745                 /*
 746                  * clear dirty, set writeback and unlock the pages.
 747                  */
 748                 extent_clear_unlock_delalloc(inode, async_extent->start,
 749                                 async_extent->start +
 750                                 async_extent->ram_size - 1,
 751                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 752                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 753                                 PAGE_SET_WRITEBACK);
 754                 ret = btrfs_submit_compressed_write(inode,
 755                                     async_extent->start,
 756                                     async_extent->ram_size,
 757                                     ins.objectid,
 758                                     ins.offset, async_extent->pages,
 759                                     async_extent->nr_pages);
 760                 alloc_hint = ins.objectid + ins.offset;
 761                 kfree(async_extent);
 762                 if (ret)
 763                         goto out;
 764                 cond_resched();
 765         }
 766         ret = 0;
 767 out:
 768         return ret;
 769 out_free_reserve:
 770         btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
 771 out_free:
 772         extent_clear_unlock_delalloc(inode, async_extent->start,
 773                                      async_extent->start +
 774                                      async_extent->ram_size - 1,
 775                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 776                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 777                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 778                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
 779         kfree(async_extent);
 780         goto again;
 781 }
 782
 783 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 784                                       u64 num_bytes)
 785 {
 786         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 787         struct extent_map *em;
 788         u64 alloc_hint = 0;
 789
 790         read_lock(&em_tree->lock);
 791         em = search_extent_mapping(em_tree, start, num_bytes);
 792         if (em) {
 793                 /*
 794                  * if block start isn't an actual block number then find the
 795                  * first block in this inode and use that as a hint.  If that
 796                  * block is also bogus then just don't worry about it.
 797                  */
 798                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 799                         free_extent_map(em);
 800                         em = search_extent_mapping(em_tree, 0, 0);
 801                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 802                                 alloc_hint = em->block_start;
 803                         if (em)
 804                                 free_extent_map(em);
 805                 } else {
 806                         alloc_hint = em->block_start;
 807                         free_extent_map(em);
 808                 }
 809         }
 810         read_unlock(&em_tree->lock);
 811
 812         return alloc_hint;
 813 }
 814
 815 /*
 816  * when extent_io.c finds a delayed allocation range in the file,
 817  * the call backs end up in this code.  The basic idea is to
 818  * allocate extents on disk for the range, and create ordered data structs
 819  * in ram to track those extents.
 820  *
 821  * locked_page is the page that writepage had locked already.  We use
 822  * it to make sure we don't do extra locks or unlocks.
 823  *
 824  * *page_started is set to one if we unlock locked_page and do everything
 825  * required to start IO on it.  It may be clean and already done with
 826  * IO when we return.
 827  */
 828 static noinline int cow_file_range(struct inode *inode,
 829                                    struct page *locked_page,
 830                                    u64 start, u64 end, int *page_started,
 831                                    unsigned long *nr_written,
 832                                    int unlock)
 833 {
 834         struct btrfs_root *root = BTRFS_I(inode)->root;
 835         u64 alloc_hint = 0;
 836         u64 num_bytes;
 837         unsigned long ram_size;
 838         u64 disk_num_bytes;
 839         u64 cur_alloc_size;
 840         u64 blocksize = root->sectorsize;
 841         struct btrfs_key ins;
 842         struct extent_map *em;
 843         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 844         int ret = 0;
 845
 846         if (btrfs_is_free_space_inode(inode)) {
 847                 WARN_ON_ONCE(1);
 848                 return -EINVAL;
 849         }
 850
 851         num_bytes = ALIGN(end - start + 1, blocksize);
 852         num_bytes = max(blocksize,  num_bytes);
 853         disk_num_bytes = num_bytes;
 854
 855         /* if this is a small write inside eof, kick off defrag */
 856         if (num_bytes < 64 * 1024 &&
 857             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 858                 btrfs_add_inode_defrag(NULL, inode);
 859
 860         if (start == 0) {
 861                 /* lets try to make an inline extent */
 862                 ret = cow_file_range_inline(root, inode, start, end, 0, 0,
 863                                             NULL);
 864                 if (ret == 0) {
 865                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 866                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 867                                      EXTENT_DEFRAG, PAGE_UNLOCK |
 868                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 869                                      PAGE_END_WRITEBACK);
 870
 871                         *nr_written = *nr_written +
 872                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
 873                         *page_started = 1;
 874                         goto out;
 875                 } else if (ret < 0) {
 876                         goto out_unlock;
 877                 }
 878         }
 879
 880         BUG_ON(disk_num_bytes >
 881                btrfs_super_total_bytes(root->fs_info->super_copy));
 882
 883         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 884         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 885
 886         while (disk_num_bytes > 0) {
 887                 unsigned long op;
 888
 889                 cur_alloc_size = disk_num_bytes;
 890                 ret = btrfs_reserve_extent(root, cur_alloc_size,
 891                                            root->sectorsize, 0, alloc_hint,
 892                                            &ins, 1);
 893                 if (ret < 0)
 894                         goto out_unlock;
 895
 896                 em = alloc_extent_map();
 897                 if (!em) {
 898                         ret = -ENOMEM;
 899                         goto out_reserve;
 900                 }
 901                 em->start = start;
 902                 em->orig_start = em->start;
 903                 ram_size = ins.offset;
 904                 em->len = ins.offset;
 905                 em->mod_start = em->start;
 906                 em->mod_len = em->len;
 907
 908                 em->block_start = ins.objectid;
 909                 em->block_len = ins.offset;
 910                 em->orig_block_len = ins.offset;
 911                 em->ram_bytes = ram_size;
 912                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 913                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 914                 em->generation = -1;
 915
 916                 while (1) {
 917                         write_lock(&em_tree->lock);
 918                         ret = add_extent_mapping(em_tree, em, 1);
 919                         write_unlock(&em_tree->lock);
 920                         if (ret != -EEXIST) {
 921                                 free_extent_map(em);
 922                                 break;
 923                         }
 924                         btrfs_drop_extent_cache(inode, start,
 925                                                 start + ram_size - 1, 0);
 926                 }
 927                 if (ret)
 928                         goto out_reserve;
 929
 930                 cur_alloc_size = ins.offset;
 931                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
 932                                                ram_size, cur_alloc_size, 0);
 933                 if (ret)
 934                         goto out_reserve;
 935
 936                 if (root->root_key.objectid ==
 937                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
 938                         ret = btrfs_reloc_clone_csums(inode, start,
 939                                                       cur_alloc_size);
 940                         if (ret)
 941                                 goto out_reserve;
 942                 }
 943
 944                 if (disk_num_bytes < cur_alloc_size)
 945                         break;
 946
 947                 /* we're not doing compressed IO, don't unlock the first
 948                  * page (which the caller expects to stay locked), don't
 949                  * clear any dirty bits and don't set any writeback bits
 950                  *
 951                  * Do set the Private2 bit so we know this page was properly
 952                  * setup for writepage
 953                  */
 954                 op = unlock ? PAGE_UNLOCK : 0;
 955                 op |= PAGE_SET_PRIVATE2;
 956
 957                 extent_clear_unlock_delalloc(inode, start,
 958                                              start + ram_size - 1, locked_page,
 959                                              EXTENT_LOCKED | EXTENT_DELALLOC,
 960                                              op);
 961                 disk_num_bytes -= cur_alloc_size;
 962                 num_bytes -= cur_alloc_size;
 963                 alloc_hint = ins.objectid + ins.offset;
 964                 start += cur_alloc_size;
 965         }
 966 out:
 967         return ret;
 968
 969 out_reserve:
 970         btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
 971 out_unlock:
 972         extent_clear_unlock_delalloc(inode, start, end, locked_page,
 973                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
 974                                      EXTENT_DELALLOC | EXTENT_DEFRAG,
 975                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 976                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
 977         goto out;
 978 }
 979
 980 /*
 981  * work queue call back to started compression on a file and pages
 982  */
 983 static noinline void async_cow_start(struct btrfs_work *work)
 984 {
 985         struct async_cow *async_cow;
 986         int num_added = 0;
 987         async_cow = container_of(work, struct async_cow, work);
 988
 989         compress_file_range(async_cow->inode, async_cow->locked_page,
 990                             async_cow->start, async_cow->end, async_cow,
 991                             &num_added);
 992         if (num_added == 0) {
 993                 btrfs_add_delayed_iput(async_cow->inode);
 994                 async_cow->inode = NULL;
 995         }
 996 }
 997
 998 /*
 999  * work queue call back to submit previously compressed pages
1000  */
1001 static noinline void async_cow_submit(struct btrfs_work *work)
1002 {
1003         struct async_cow *async_cow;
1004         struct btrfs_root *root;
1005         unsigned long nr_pages;
1006
1007         async_cow = container_of(work, struct async_cow, work);
1008
1009         root = async_cow->root;
1010         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
1011                 PAGE_CACHE_SHIFT;
1012
1013         if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <
1014             5 * 1024 * 1024 &&
1015             waitqueue_active(&root->fs_info->async_submit_wait))
1016                 wake_up(&root->fs_info->async_submit_wait);
1017
1018         if (async_cow->inode)
1019                 submit_compressed_extents(async_cow->inode, async_cow);
1020 }
1021
1022 static noinline void async_cow_free(struct btrfs_work *work)
1023 {
1024         struct async_cow *async_cow;
1025         async_cow = container_of(work, struct async_cow, work);
1026         if (async_cow->inode)
1027                 btrfs_add_delayed_iput(async_cow->inode);
1028         kfree(async_cow);
1029 }
1030
1031 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1032                                 u64 start, u64 end, int *page_started,
1033                                 unsigned long *nr_written)
1034 {
1035         struct async_cow *async_cow;
1036         struct btrfs_root *root = BTRFS_I(inode)->root;
1037         unsigned long nr_pages;
1038         u64 cur_end;
1039         int limit = 10 * 1024 * 1024;
1040
1041         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1042                          1, 0, NULL, GFP_NOFS);
1043         while (start < end) {
1044                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1045                 BUG_ON(!async_cow); /* -ENOMEM */
1046                 async_cow->inode = igrab(inode);
1047                 async_cow->root = root;
1048                 async_cow->locked_page = locked_page;
1049                 async_cow->start = start;
1050
1051                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
1052                         cur_end = end;
1053                 else
1054                         cur_end = min(end, start + 512 * 1024 - 1);
1055
1056                 async_cow->end = cur_end;
1057                 INIT_LIST_HEAD(&async_cow->extents);
1058
1059                 async_cow->work.func = async_cow_start;
1060                 async_cow->work.ordered_func = async_cow_submit;
1061                 async_cow->work.ordered_free = async_cow_free;
1062                 async_cow->work.flags = 0;
1063
1064                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
1065                         PAGE_CACHE_SHIFT;
1066                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
1067
1068                 btrfs_queue_worker(&root->fs_info->delalloc_workers,
1069                                    &async_cow->work);
1070
1071                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1072                         wait_event(root->fs_info->async_submit_wait,
1073                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1074                             limit));
1075                 }
1076
1077                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1078                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1079                         wait_event(root->fs_info->async_submit_wait,
1080                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1081                            0));
1082                 }
1083
1084                 *nr_written += nr_pages;
1085                 start = cur_end + 1;
1086         }
1087         *page_started = 1;
1088         return 0;
1089 }
1090
1091 static noinline int csum_exist_in_range(struct btrfs_root *root,
1092                                         u64 bytenr, u64 num_bytes)
1093 {
1094         int ret;
1095         struct btrfs_ordered_sum *sums;
1096         LIST_HEAD(list);
1097
1098         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1099                                        bytenr + num_bytes - 1, &list, 0);
1100         if (ret == 0 && list_empty(&list))
1101                 return 0;
1102
1103         while (!list_empty(&list)) {
1104                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1105                 list_del(&sums->list);
1106                 kfree(sums);
1107         }
1108         return 1;
1109 }
1110
1111 /*
1112  * when nowcow writeback call back.  This checks for snapshots or COW copies
1113  * of the extents that exist in the file, and COWs the file as required.
1114  *
1115  * If no cow copies or snapshots exist, we write directly to the existing
1116  * blocks on disk
1117  */
1118 static noinline int run_delalloc_nocow(struct inode *inode,
1119                                        struct page *locked_page,
1120                               u64 start, u64 end, int *page_started, int force,
1121                               unsigned long *nr_written)
1122 {
1123         struct btrfs_root *root = BTRFS_I(inode)->root;
1124         struct btrfs_trans_handle *trans;
1125         struct extent_buffer *leaf;
1126         struct btrfs_path *path;
1127         struct btrfs_file_extent_item *fi;
1128         struct btrfs_key found_key;
1129         u64 cow_start;
1130         u64 cur_offset;
1131         u64 extent_end;
1132         u64 extent_offset;
1133         u64 disk_bytenr;
1134         u64 num_bytes;
1135         u64 disk_num_bytes;
1136         u64 ram_bytes;
1137         int extent_type;
1138         int ret, err;
1139         int type;
1140         int nocow;
1141         int check_prev = 1;
1142         bool nolock;
1143         u64 ino = btrfs_ino(inode);
1144
1145         path = btrfs_alloc_path();
1146         if (!path) {
1147                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1148                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1149                                              EXTENT_DO_ACCOUNTING |
1150                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1151                                              PAGE_CLEAR_DIRTY |
1152                                              PAGE_SET_WRITEBACK |
1153                                              PAGE_END_WRITEBACK);
1154                 return -ENOMEM;
1155         }
1156
1157         nolock = btrfs_is_free_space_inode(inode);
1158
1159         if (nolock)
1160                 trans = btrfs_join_transaction_nolock(root);
1161         else
1162                 trans = btrfs_join_transaction(root);
1163
1164         if (IS_ERR(trans)) {
1165                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1166                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1167                                              EXTENT_DO_ACCOUNTING |
1168                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1169                                              PAGE_CLEAR_DIRTY |
1170                                              PAGE_SET_WRITEBACK |
1171                                              PAGE_END_WRITEBACK);
1172                 btrfs_free_path(path);
1173                 return PTR_ERR(trans);
1174         }
1175
1176         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1177
1178         cow_start = (u64)-1;
1179         cur_offset = start;
1180         while (1) {
1181                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1182                                                cur_offset, 0);
1183                 if (ret < 0)
1184                         goto error;
1185                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1186                         leaf = path->nodes[0];
1187                         btrfs_item_key_to_cpu(leaf, &found_key,
1188                                               path->slots[0] - 1);
1189                         if (found_key.objectid == ino &&
1190                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1191                                 path->slots[0]--;
1192                 }
1193                 check_prev = 0;
1194 next_slot:
1195                 leaf = path->nodes[0];
1196                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1197                         ret = btrfs_next_leaf(root, path);
1198                         if (ret < 0)
1199                                 goto error;
1200                         if (ret > 0)
1201                                 break;
1202                         leaf = path->nodes[0];
1203                 }
1204
1205                 nocow = 0;
1206                 disk_bytenr = 0;
1207                 num_bytes = 0;
1208                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1209
1210                 if (found_key.objectid > ino ||
1211                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1212                     found_key.offset > end)
1213                         break;
1214
1215                 if (found_key.offset > cur_offset) {
1216                         extent_end = found_key.offset;
1217                         extent_type = 0;
1218                         goto out_check;
1219                 }
1220
1221                 fi = btrfs_item_ptr(leaf, path->slots[0],
1222                                     struct btrfs_file_extent_item);
1223                 extent_type = btrfs_file_extent_type(leaf, fi);
1224
1225                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1226                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1227                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1228                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1229                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1230                         extent_end = found_key.offset +
1231                                 btrfs_file_extent_num_bytes(leaf, fi);
1232                         disk_num_bytes =
1233                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1234                         if (extent_end <= start) {
1235                                 path->slots[0]++;
1236                                 goto next_slot;
1237                         }
1238                         if (disk_bytenr == 0)
1239                                 goto out_check;
1240                         if (btrfs_file_extent_compression(leaf, fi) ||
1241                             btrfs_file_extent_encryption(leaf, fi) ||
1242                             btrfs_file_extent_other_encoding(leaf, fi))
1243                                 goto out_check;
1244                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1245                                 goto out_check;
1246                         if (btrfs_extent_readonly(root, disk_bytenr))
1247                                 goto out_check;
1248                         if (btrfs_cross_ref_exist(trans, root, ino,
1249                                                   found_key.offset -
1250                                                   extent_offset, disk_bytenr))
1251                                 goto out_check;
1252                         disk_bytenr += extent_offset;
1253                         disk_bytenr += cur_offset - found_key.offset;
1254                         num_bytes = min(end + 1, extent_end) - cur_offset;
1255                         /*
1256                          * force cow if csum exists in the range.
1257                          * this ensure that csum for a given extent are
1258                          * either valid or do not exist.
1259                          */
1260                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1261                                 goto out_check;
1262                         nocow = 1;
1263                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1264                         extent_end = found_key.offset +
1265                                 btrfs_file_extent_inline_len(leaf, fi);
1266                         extent_end = ALIGN(extent_end, root->sectorsize);
1267                 } else {
1268                         BUG_ON(1);
1269                 }
1270 out_check:
1271                 if (extent_end <= start) {
1272                         path->slots[0]++;
1273                         goto next_slot;
1274                 }
1275                 if (!nocow) {
1276                         if (cow_start == (u64)-1)
1277                                 cow_start = cur_offset;
1278                         cur_offset = extent_end;
1279                         if (cur_offset > end)
1280                                 break;
1281                         path->slots[0]++;
1282                         goto next_slot;
1283                 }
1284
1285                 btrfs_release_path(path);
1286                 if (cow_start != (u64)-1) {
1287                         ret = cow_file_range(inode, locked_page,
1288                                              cow_start, found_key.offset - 1,
1289                                              page_started, nr_written, 1);
1290                         if (ret)
1291                                 goto error;
1292                         cow_start = (u64)-1;
1293                 }
1294
1295                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1296                         struct extent_map *em;
1297                         struct extent_map_tree *em_tree;
1298                         em_tree = &BTRFS_I(inode)->extent_tree;
1299                         em = alloc_extent_map();
1300                         BUG_ON(!em); /* -ENOMEM */
1301                         em->start = cur_offset;
1302                         em->orig_start = found_key.offset - extent_offset;
1303                         em->len = num_bytes;
1304                         em->block_len = num_bytes;
1305                         em->block_start = disk_bytenr;
1306                         em->orig_block_len = disk_num_bytes;
1307                         em->ram_bytes = ram_bytes;
1308                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1309                         em->mod_start = em->start;
1310                         em->mod_len = em->len;
1311                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1312                         set_bit(EXTENT_FLAG_FILLING, &em->flags);
1313                         em->generation = -1;
1314                         while (1) {
1315                                 write_lock(&em_tree->lock);
1316                                 ret = add_extent_mapping(em_tree, em, 1);
1317                                 write_unlock(&em_tree->lock);
1318                                 if (ret != -EEXIST) {
1319                                         free_extent_map(em);
1320                                         break;
1321                                 }
1322                                 btrfs_drop_extent_cache(inode, em->start,
1323                                                 em->start + em->len - 1, 0);
1324                         }
1325                         type = BTRFS_ORDERED_PREALLOC;
1326                 } else {
1327                         type = BTRFS_ORDERED_NOCOW;
1328                 }
1329
1330                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1331                                                num_bytes, num_bytes, type);
1332                 BUG_ON(ret); /* -ENOMEM */
1333
1334                 if (root->root_key.objectid ==
1335                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1336                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1337                                                       num_bytes);
1338                         if (ret)
1339                                 goto error;
1340                 }
1341
1342                 extent_clear_unlock_delalloc(inode, cur_offset,
1343                                              cur_offset + num_bytes - 1,
1344                                              locked_page, EXTENT_LOCKED |
1345                                              EXTENT_DELALLOC, PAGE_UNLOCK |
1346                                              PAGE_SET_PRIVATE2);
1347                 cur_offset = extent_end;
1348                 if (cur_offset > end)
1349                         break;
1350         }
1351         btrfs_release_path(path);
1352
1353         if (cur_offset <= end && cow_start == (u64)-1) {
1354                 cow_start = cur_offset;
1355                 cur_offset = end;
1356         }
1357
1358         if (cow_start != (u64)-1) {
1359                 ret = cow_file_range(inode, locked_page, cow_start, end,
1360                                      page_started, nr_written, 1);
1361                 if (ret)
1362                         goto error;
1363         }
1364
1365 error:
1366         err = btrfs_end_transaction(trans, root);
1367         if (!ret)
1368                 ret = err;
1369
1370         if (ret && cur_offset < end)
1371                 extent_clear_unlock_delalloc(inode, cur_offset, end,
1372                                              locked_page, EXTENT_LOCKED |
1373                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1374                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1375                                              PAGE_CLEAR_DIRTY |
1376                                              PAGE_SET_WRITEBACK |
1377                                              PAGE_END_WRITEBACK);
1378         btrfs_free_path(path);
1379         return ret;
1380 }
1381
1382 /*
1383  * extent_io.c call back to do delayed allocation processing
1384  */
1385 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1386                               u64 start, u64 end, int *page_started,
1387                               unsigned long *nr_written)
1388 {
1389         int ret;
1390         struct btrfs_root *root = BTRFS_I(inode)->root;
1391
1392         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) {
1393                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1394                                          page_started, 1, nr_written);
1395         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC) {
1396                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1397                                          page_started, 0, nr_written);
1398         } else if (!btrfs_test_opt(root, COMPRESS) &&
1399                    !(BTRFS_I(inode)->force_compress) &&
1400                    !(BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS)) {
1401                 ret = cow_file_range(inode, locked_page, start, end,
1402                                       page_started, nr_written, 1);
1403         } else {
1404                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1405                         &BTRFS_I(inode)->runtime_flags);
1406                 ret = cow_file_range_async(inode, locked_page, start, end,
1407                                            page_started, nr_written);
1408         }
1409         return ret;
1410 }
1411
1412 static void btrfs_split_extent_hook(struct inode *inode,
1413                                     struct extent_state *orig, u64 split)
1414 {
1415         /* not delalloc, ignore it */
1416         if (!(orig->state & EXTENT_DELALLOC))
1417                 return;
1418
1419         spin_lock(&BTRFS_I(inode)->lock);
1420         BTRFS_I(inode)->outstanding_extents++;
1421         spin_unlock(&BTRFS_I(inode)->lock);
1422 }
1423
1424 /*
1425  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1426  * extents so we can keep track of new extents that are just merged onto old
1427  * extents, such as when we are doing sequential writes, so we can properly
1428  * account for the metadata space we'll need.
1429  */
1430 static void btrfs_merge_extent_hook(struct inode *inode,
1431                                     struct extent_state *new,
1432                                     struct extent_state *other)
1433 {
1434         /* not delalloc, ignore it */
1435         if (!(other->state & EXTENT_DELALLOC))
1436                 return;
1437
1438         spin_lock(&BTRFS_I(inode)->lock);
1439         BTRFS_I(inode)->outstanding_extents--;
1440         spin_unlock(&BTRFS_I(inode)->lock);
1441 }
1442
1443 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1444                                       struct inode *inode)
1445 {
1446         spin_lock(&root->delalloc_lock);
1447         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1448                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1449                               &root->delalloc_inodes);
1450                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1451                         &BTRFS_I(inode)->runtime_flags);
1452                 root->nr_delalloc_inodes++;
1453                 if (root->nr_delalloc_inodes == 1) {
1454                         spin_lock(&root->fs_info->delalloc_root_lock);
1455                         BUG_ON(!list_empty(&root->delalloc_root));
1456                         list_add_tail(&root->delalloc_root,
1457                                       &root->fs_info->delalloc_roots);
1458                         spin_unlock(&root->fs_info->delalloc_root_lock);
1459                 }
1460         }
1461         spin_unlock(&root->delalloc_lock);
1462 }
1463
1464 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1465                                      struct inode *inode)
1466 {
1467         spin_lock(&root->delalloc_lock);
1468         if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1469                 list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1470                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1471                           &BTRFS_I(inode)->runtime_flags);
1472                 root->nr_delalloc_inodes--;
1473                 if (!root->nr_delalloc_inodes) {
1474                         spin_lock(&root->fs_info->delalloc_root_lock);
1475                         BUG_ON(list_empty(&root->delalloc_root));
1476                         list_del_init(&root->delalloc_root);
1477                         spin_unlock(&root->fs_info->delalloc_root_lock);
1478                 }
1479         }
1480         spin_unlock(&root->delalloc_lock);
1481 }
1482
1483 /*
1484  * extent_io.c set_bit_hook, used to track delayed allocation
1485  * bytes in this file, and to maintain the list of inodes that
1486  * have pending delalloc work to be done.
1487  */
1488 static void btrfs_set_bit_hook(struct inode *inode,
1489                                struct extent_state *state, unsigned long *bits)
1490 {
1491
1492         /*
1493          * set_bit and clear bit hooks normally require _irqsave/restore
1494          * but in this case, we are only testing for the DELALLOC
1495          * bit, which is only set or cleared with irqs on
1496          */
1497         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1498                 struct btrfs_root *root = BTRFS_I(inode)->root;
1499                 u64 len = state->end + 1 - state->start;
1500                 bool do_list = !btrfs_is_free_space_inode(inode);
1501
1502                 if (*bits & EXTENT_FIRST_DELALLOC) {
1503                         *bits &= ~EXTENT_FIRST_DELALLOC;
1504                 } else {
1505                         spin_lock(&BTRFS_I(inode)->lock);
1506                         BTRFS_I(inode)->outstanding_extents++;
1507                         spin_unlock(&BTRFS_I(inode)->lock);
1508                 }
1509
1510                 __percpu_counter_add(&root->fs_info->delalloc_bytes, len,
1511                                      root->fs_info->delalloc_batch);
1512                 spin_lock(&BTRFS_I(inode)->lock);
1513                 BTRFS_I(inode)->delalloc_bytes += len;
1514                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1515                                          &BTRFS_I(inode)->runtime_flags))
1516                         btrfs_add_delalloc_inodes(root, inode);
1517                 spin_unlock(&BTRFS_I(inode)->lock);
1518         }
1519 }
1520
1521 /*
1522  * extent_io.c clear_bit_hook, see set_bit_hook for why
1523  */
1524 static void btrfs_clear_bit_hook(struct inode *inode,
1525                                  struct extent_state *state,
1526                                  unsigned long *bits)
1527 {
1528         /*
1529          * set_bit and clear bit hooks normally require _irqsave/restore
1530          * but in this case, we are only testing for the DELALLOC
1531          * bit, which is only set or cleared with irqs on
1532          */
1533         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1534                 struct btrfs_root *root = BTRFS_I(inode)->root;
1535                 u64 len = state->end + 1 - state->start;
1536                 bool do_list = !btrfs_is_free_space_inode(inode);
1537
1538                 if (*bits & EXTENT_FIRST_DELALLOC) {
1539                         *bits &= ~EXTENT_FIRST_DELALLOC;
1540                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1541                         spin_lock(&BTRFS_I(inode)->lock);
1542                         BTRFS_I(inode)->outstanding_extents--;
1543                         spin_unlock(&BTRFS_I(inode)->lock);
1544                 }
1545
1546                 /*
1547                  * We don't reserve metadata space for space cache inodes so we
1548                  * don't need to call dellalloc_release_metadata if there is an
1549                  * error.
1550                  */
1551                 if (*bits & EXTENT_DO_ACCOUNTING &&
1552                     root != root->fs_info->tree_root)
1553                         btrfs_delalloc_release_metadata(inode, len);
1554
1555                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1556                     && do_list && !(state->state & EXTENT_NORESERVE))
1557                         btrfs_free_reserved_data_space(inode, len);
1558
1559                 __percpu_counter_add(&root->fs_info->delalloc_bytes, -len,
1560                                      root->fs_info->delalloc_batch);
1561                 spin_lock(&BTRFS_I(inode)->lock);
1562                 BTRFS_I(inode)->delalloc_bytes -= len;
1563                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1564                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1565                              &BTRFS_I(inode)->runtime_flags))
1566                         btrfs_del_delalloc_inode(root, inode);
1567                 spin_unlock(&BTRFS_I(inode)->lock);
1568         }
1569 }
1570
1571 /*
1572  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1573  * we don't create bios that span stripes or chunks
1574  */
1575 int btrfs_merge_bio_hook(int rw, struct page *page, unsigned long offset,
1576                          size_t size, struct bio *bio,
1577                          unsigned long bio_flags)
1578 {
1579         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1580         u64 logical = (u64)bio->bi_sector << 9;
1581         u64 length = 0;
1582         u64 map_length;
1583         int ret;
1584
1585         if (bio_flags & EXTENT_BIO_COMPRESSED)
1586                 return 0;
1587
1588         length = bio->bi_size;
1589         map_length = length;
1590         ret = btrfs_map_block(root->fs_info, rw, logical,
1591                               &map_length, NULL, 0);
1592         /* Will always return 0 with map_multi == NULL */
1593         BUG_ON(ret < 0);
1594         if (map_length < length + size)
1595                 return 1;
1596         return 0;
1597 }
1598
1599 /*
1600  * in order to insert checksums into the metadata in large chunks,
1601  * we wait until bio submission time.   All the pages in the bio are
1602  * checksummed and sums are attached onto the ordered extent record.
1603  *
1604  * At IO completion time the cums attached on the ordered extent record
1605  * are inserted into the btree
1606  */
1607 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1608                                     struct bio *bio, int mirror_num,
1609                                     unsigned long bio_flags,
1610                                     u64 bio_offset)
1611 {
1612         struct btrfs_root *root = BTRFS_I(inode)->root;
1613         int ret = 0;
1614
1615         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1616         BUG_ON(ret); /* -ENOMEM */
1617         return 0;
1618 }
1619
1620 /*
1621  * in order to insert checksums into the metadata in large chunks,
1622  * we wait until bio submission time.   All the pages in the bio are
1623  * checksummed and sums are attached onto the ordered extent record.
1624  *
1625  * At IO completion time the cums attached on the ordered extent record
1626  * are inserted into the btree
1627  */
1628 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1629                           int mirror_num, unsigned long bio_flags,
1630                           u64 bio_offset)
1631 {
1632         struct btrfs_root *root = BTRFS_I(inode)->root;
1633         int ret;
1634
1635         ret = btrfs_map_bio(root, rw, bio, mirror_num, 1);
1636         if (ret)
1637                 bio_endio(bio, ret);
1638         return ret;
1639 }
1640
1641 /*
1642  * extent_io.c submission hook. This does the right thing for csum calculation
1643  * on write, or reading the csums from the tree before a read
1644  */
1645 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1646                           int mirror_num, unsigned long bio_flags,
1647                           u64 bio_offset)
1648 {
1649         struct btrfs_root *root = BTRFS_I(inode)->root;
1650         int ret = 0;
1651         int skip_sum;
1652         int metadata = 0;
1653         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1654
1655         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1656
1657         if (btrfs_is_free_space_inode(inode))
1658                 metadata = 2;
1659
1660         if (!(rw & REQ_WRITE)) {
1661                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, metadata);
1662                 if (ret)
1663                         goto out;
1664
1665                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1666                         ret = btrfs_submit_compressed_read(inode, bio,
1667                                                            mirror_num,
1668                                                            bio_flags);
1669                         goto out;
1670                 } else if (!skip_sum) {
1671                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1672                         if (ret)
1673                                 goto out;
1674                 }
1675                 goto mapit;
1676         } else if (async && !skip_sum) {
1677                 /* csum items have already been cloned */
1678                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1679                         goto mapit;
1680                 /* we're doing a write, do the async checksumming */
1681                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1682                                    inode, rw, bio, mirror_num,
1683                                    bio_flags, bio_offset,
1684                                    __btrfs_submit_bio_start,
1685                                    __btrfs_submit_bio_done);
1686                 goto out;
1687         } else if (!skip_sum) {
1688                 ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1689                 if (ret)
1690                         goto out;
1691         }
1692
1693 mapit:
1694         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
1695
1696 out:
1697         if (ret < 0)
1698                 bio_endio(bio, ret);
1699         return ret;
1700 }
1701
1702 /*
1703  * given a list of ordered sums record them in the inode.  This happens
1704  * at IO completion time based on sums calculated at bio submission time.
1705  */
1706 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1707                              struct inode *inode, u64 file_offset,
1708                              struct list_head *list)
1709 {
1710         struct btrfs_ordered_sum *sum;
1711
1712         list_for_each_entry(sum, list, list) {
1713                 trans->adding_csums = 1;
1714                 btrfs_csum_file_blocks(trans,
1715                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1716                 trans->adding_csums = 0;
1717         }
1718         return 0;
1719 }
1720
1721 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1722                               struct extent_state **cached_state)
1723 {
1724         WARN_ON((end & (PAGE_CACHE_SIZE - 1)) == 0);
1725         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1726                                    cached_state, GFP_NOFS);
1727 }
1728
1729 /* see btrfs_writepage_start_hook for details on why this is required */
1730 struct btrfs_writepage_fixup {
1731         struct page *page;
1732         struct btrfs_work work;
1733 };
1734
1735 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1736 {
1737         struct btrfs_writepage_fixup *fixup;
1738         struct btrfs_ordered_extent *ordered;
1739         struct extent_state *cached_state = NULL;
1740         struct page *page;
1741         struct inode *inode;
1742         u64 page_start;
1743         u64 page_end;
1744         int ret;
1745
1746         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1747         page = fixup->page;
1748 again:
1749         lock_page(page);
1750         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1751                 ClearPageChecked(page);
1752                 goto out_page;
1753         }
1754
1755         inode = page->mapping->host;
1756         page_start = page_offset(page);
1757         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1758
1759         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1760                          &cached_state);
1761
1762         /* already ordered? We're done */
1763         if (PagePrivate2(page))
1764                 goto out;
1765
1766         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1767         if (ordered) {
1768                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1769                                      page_end, &cached_state, GFP_NOFS);
1770                 unlock_page(page);
1771                 btrfs_start_ordered_extent(inode, ordered, 1);
1772                 btrfs_put_ordered_extent(ordered);
1773                 goto again;
1774         }
1775
1776         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
1777         if (ret) {
1778                 mapping_set_error(page->mapping, ret);
1779                 end_extent_writepage(page, ret, page_start, page_end);
1780                 ClearPageChecked(page);
1781                 goto out;
1782          }
1783
1784         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1785         ClearPageChecked(page);
1786         set_page_dirty(page);
1787 out:
1788         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1789                              &cached_state, GFP_NOFS);
1790 out_page:
1791         unlock_page(page);
1792         page_cache_release(page);
1793         kfree(fixup);
1794 }
1795
1796 /*
1797  * There are a few paths in the higher layers of the kernel that directly
1798  * set the page dirty bit without asking the filesystem if it is a
1799  * good idea.  This causes problems because we want to make sure COW
1800  * properly happens and the data=ordered rules are followed.
1801  *
1802  * In our case any range that doesn't have the ORDERED bit set
1803  * hasn't been properly setup for IO.  We kick off an async process
1804  * to fix it up.  The async helper will wait for ordered extents, set
1805  * the delalloc bit and make it safe to write the page.
1806  */
1807 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1808 {
1809         struct inode *inode = page->mapping->host;
1810         struct btrfs_writepage_fixup *fixup;
1811         struct btrfs_root *root = BTRFS_I(inode)->root;
1812
1813         /* this page is properly in the ordered list */
1814         if (TestClearPagePrivate2(page))
1815                 return 0;
1816
1817         if (PageChecked(page))
1818                 return -EAGAIN;
1819
1820         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1821         if (!fixup)
1822                 return -EAGAIN;
1823
1824         SetPageChecked(page);
1825         page_cache_get(page);
1826         fixup->work.func = btrfs_writepage_fixup_worker;
1827         fixup->page = page;
1828         btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
1829         return -EBUSY;
1830 }
1831
1832 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1833                                        struct inode *inode, u64 file_pos,
1834                                        u64 disk_bytenr, u64 disk_num_bytes,
1835                                        u64 num_bytes, u64 ram_bytes,
1836                                        u8 compression, u8 encryption,
1837                                        u16 other_encoding, int extent_type)
1838 {
1839         struct btrfs_root *root = BTRFS_I(inode)->root;
1840         struct btrfs_file_extent_item *fi;
1841         struct btrfs_path *path;
1842         struct extent_buffer *leaf;
1843         struct btrfs_key ins;
1844         int ret;
1845
1846         path = btrfs_alloc_path();
1847         if (!path)
1848                 return -ENOMEM;
1849
1850         path->leave_spinning = 1;
1851
1852         /*
1853          * we may be replacing one extent in the tree with another.
1854          * The new extent is pinned in the extent map, and we don't want
1855          * to drop it from the cache until it is completely in the btree.
1856          *
1857          * So, tell btrfs_drop_extents to leave this extent in the cache.
1858          * the caller is expected to unpin it and allow it to be merged
1859          * with the others.
1860          */
1861         ret = btrfs_drop_extents(trans, root, inode, file_pos,
1862                                  file_pos + num_bytes, 0);
1863         if (ret)
1864                 goto out;
1865
1866         ins.objectid = btrfs_ino(inode);
1867         ins.offset = file_pos;
1868         ins.type = BTRFS_EXTENT_DATA_KEY;
1869         ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*fi));
1870         if (ret)
1871                 goto out;
1872         leaf = path->nodes[0];
1873         fi = btrfs_item_ptr(leaf, path->slots[0],
1874                             struct btrfs_file_extent_item);
1875         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1876         btrfs_set_file_extent_type(leaf, fi, extent_type);
1877         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1878         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1879         btrfs_set_file_extent_offset(leaf, fi, 0);
1880         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1881         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1882         btrfs_set_file_extent_compression(leaf, fi, compression);
1883         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1884         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1885
1886         btrfs_mark_buffer_dirty(leaf);
1887         btrfs_release_path(path);
1888
1889         inode_add_bytes(inode, num_bytes);
1890
1891         ins.objectid = disk_bytenr;
1892         ins.offset = disk_num_bytes;
1893         ins.type = BTRFS_EXTENT_ITEM_KEY;
1894         ret = btrfs_alloc_reserved_file_extent(trans, root,
1895                                         root->root_key.objectid,
1896                                         btrfs_ino(inode), file_pos, &ins);
1897 out:
1898         btrfs_free_path(path);
1899
1900         return ret;
1901 }
1902
1903 /* snapshot-aware defrag */
1904 struct sa_defrag_extent_backref {
1905         struct rb_node node;
1906         struct old_sa_defrag_extent *old;
1907         u64 root_id;
1908         u64 inum;
1909         u64 file_pos;
1910         u64 extent_offset;
1911         u64 num_bytes;
1912         u64 generation;
1913 };
1914
1915 struct old_sa_defrag_extent {
1916         struct list_head list;
1917         struct new_sa_defrag_extent *new;
1918
1919         u64 extent_offset;
1920         u64 bytenr;
1921         u64 offset;
1922         u64 len;
1923         int count;
1924 };
1925
1926 struct new_sa_defrag_extent {
1927         struct rb_root root;
1928         struct list_head head;
1929         struct btrfs_path *path;
1930         struct inode *inode;
1931         u64 file_pos;
1932         u64 len;
1933         u64 bytenr;
1934         u64 disk_len;
1935         u8 compress_type;
1936 };
1937
1938 static int backref_comp(struct sa_defrag_extent_backref *b1,
1939                         struct sa_defrag_extent_backref *b2)
1940 {
1941         if (b1->root_id < b2->root_id)
1942                 return -1;
1943         else if (b1->root_id > b2->root_id)
1944                 return 1;
1945
1946         if (b1->inum < b2->inum)
1947                 return -1;
1948         else if (b1->inum > b2->inum)
1949                 return 1;
1950
1951         if (b1->file_pos < b2->file_pos)
1952                 return -1;
1953         else if (b1->file_pos > b2->file_pos)
1954                 return 1;
1955
1956         /*
1957          * [------------------------------] ===> (a range of space)
1958          *     |<--->|   |<---->| =============> (fs/file tree A)
1959          * |<---------------------------->| ===> (fs/file tree B)
1960          *
1961          * A range of space can refer to two file extents in one tree while
1962          * refer to only one file extent in another tree.
1963          *
1964          * So we may process a disk offset more than one time(two extents in A)
1965          * and locate at the same extent(one extent in B), then insert two same
1966          * backrefs(both refer to the extent in B).
1967          */
1968         return 0;
1969 }
1970
1971 static void backref_insert(struct rb_root *root,
1972                            struct sa_defrag_extent_backref *backref)
1973 {
1974         struct rb_node **p = &root->rb_node;
1975         struct rb_node *parent = NULL;
1976         struct sa_defrag_extent_backref *entry;
1977         int ret;
1978
1979         while (*p) {
1980                 parent = *p;
1981                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
1982
1983                 ret = backref_comp(backref, entry);
1984                 if (ret < 0)
1985                         p = &(*p)->rb_left;
1986                 else
1987                         p = &(*p)->rb_right;
1988         }
1989
1990         rb_link_node(&backref->node, parent, p);
1991         rb_insert_color(&backref->node, root);
1992 }
1993
1994 /*
1995  * Note the backref might has changed, and in this case we just return 0.
1996  */
1997 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
1998                                        void *ctx)
1999 {
2000         struct btrfs_file_extent_item *extent;
2001         struct btrfs_fs_info *fs_info;
2002         struct old_sa_defrag_extent *old = ctx;
2003         struct new_sa_defrag_extent *new = old->new;
2004         struct btrfs_path *path = new->path;
2005         struct btrfs_key key;
2006         struct btrfs_root *root;
2007         struct sa_defrag_extent_backref *backref;
2008         struct extent_buffer *leaf;
2009         struct inode *inode = new->inode;
2010         int slot;
2011         int ret;
2012         u64 extent_offset;
2013         u64 num_bytes;
2014
2015         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2016             inum == btrfs_ino(inode))
2017                 return 0;
2018
2019         key.objectid = root_id;
2020         key.type = BTRFS_ROOT_ITEM_KEY;
2021         key.offset = (u64)-1;
2022
2023         fs_info = BTRFS_I(inode)->root->fs_info;
2024         root = btrfs_read_fs_root_no_name(fs_info, &key);
2025         if (IS_ERR(root)) {
2026                 if (PTR_ERR(root) == -ENOENT)
2027                         return 0;
2028                 WARN_ON(1);
2029                 pr_debug("inum=%llu, offset=%llu, root_id=%llu\n",
2030                          inum, offset, root_id);
2031                 return PTR_ERR(root);
2032         }
2033
2034         key.objectid = inum;
2035         key.type = BTRFS_EXTENT_DATA_KEY;
2036         if (offset > (u64)-1 << 32)
2037                 key.offset = 0;
2038         else
2039                 key.offset = offset;
2040
2041         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2042         if (WARN_ON(ret < 0))
2043                 return ret;
2044         ret = 0;
2045
2046         while (1) {
2047                 cond_resched();
2048
2049                 leaf = path->nodes[0];
2050                 slot = path->slots[0];
2051
2052                 if (slot >= btrfs_header_nritems(leaf)) {
2053                         ret = btrfs_next_leaf(root, path);
2054                         if (ret < 0) {
2055                                 goto out;
2056                         } else if (ret > 0) {
2057                                 ret = 0;
2058                                 goto out;
2059                         }
2060                         continue;
2061                 }
2062
2063                 path->slots[0]++;
2064
2065                 btrfs_item_key_to_cpu(leaf, &key, slot);
2066
2067                 if (key.objectid > inum)
2068                         goto out;
2069
2070                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2071                         continue;
2072
2073                 extent = btrfs_item_ptr(leaf, slot,
2074                                         struct btrfs_file_extent_item);
2075
2076                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2077                         continue;
2078
2079                 /*
2080                  * 'offset' refers to the exact key.offset,
2081                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2082                  * (key.offset - extent_offset).
2083                  */
2084                 if (key.offset != offset)
2085                         continue;
2086
2087                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2088                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2089
2090                 if (extent_offset >= old->extent_offset + old->offset +
2091                     old->len || extent_offset + num_bytes <=
2092                     old->extent_offset + old->offset)
2093                         continue;
2094                 break;
2095         }
2096
2097         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2098         if (!backref) {
2099                 ret = -ENOENT;
2100                 goto out;
2101         }
2102
2103         backref->root_id = root_id;
2104         backref->inum = inum;
2105         backref->file_pos = offset;
2106         backref->num_bytes = num_bytes;
2107         backref->extent_offset = extent_offset;
2108         backref->generation = btrfs_file_extent_generation(leaf, extent);
2109         backref->old = old;
2110         backref_insert(&new->root, backref);
2111         old->count++;
2112 out:
2113         btrfs_release_path(path);
2114         WARN_ON(ret);
2115         return ret;
2116 }
2117
2118 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2119                                    struct new_sa_defrag_extent *new)
2120 {
2121         struct btrfs_fs_info *fs_info = BTRFS_I(new->inode)->root->fs_info;
2122         struct old_sa_defrag_extent *old, *tmp;
2123         int ret;
2124
2125         new->path = path;
2126
2127         list_for_each_entry_safe(old, tmp, &new->head, list) {
2128                 ret = iterate_inodes_from_logical(old->bytenr +
2129                                                   old->extent_offset, fs_info,
2130                                                   path, record_one_backref,
2131                                                   old);
2132                 if (ret < 0 && ret != -ENOENT)
2133                         return false;
2134
2135                 /* no backref to be processed for this extent */
2136                 if (!old->count) {
2137                         list_del(&old->list);
2138                         kfree(old);
2139                 }
2140         }
2141
2142         if (list_empty(&new->head))
2143                 return false;
2144
2145         return true;
2146 }
2147
2148 static int relink_is_mergable(struct extent_buffer *leaf,
2149                               struct btrfs_file_extent_item *fi,
2150                               struct new_sa_defrag_extent *new)
2151 {
2152         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2153                 return 0;
2154
2155         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2156                 return 0;
2157
2158         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2159                 return 0;
2160
2161         if (btrfs_file_extent_encryption(leaf, fi) ||
2162             btrfs_file_extent_other_encoding(leaf, fi))
2163                 return 0;
2164
2165         return 1;
2166 }
2167
2168 /*
2169  * Note the backref might has changed, and in this case we just return 0.
2170  */
2171 static noinline int relink_extent_backref(struct btrfs_path *path,
2172                                  struct sa_defrag_extent_backref *prev,
2173                                  struct sa_defrag_extent_backref *backref)
2174 {
2175         struct btrfs_file_extent_item *extent;
2176         struct btrfs_file_extent_item *item;
2177         struct btrfs_ordered_extent *ordered;
2178         struct btrfs_trans_handle *trans;
2179         struct btrfs_fs_info *fs_info;
2180         struct btrfs_root *root;
2181         struct btrfs_key key;
2182         struct extent_buffer *leaf;
2183         struct old_sa_defrag_extent *old = backref->old;
2184         struct new_sa_defrag_extent *new = old->new;
2185         struct inode *src_inode = new->inode;
2186         struct inode *inode;
2187         struct extent_state *cached = NULL;
2188         int ret = 0;
2189         u64 start;
2190         u64 len;
2191         u64 lock_start;
2192         u64 lock_end;
2193         bool merge = false;
2194         int index;
2195
2196         if (prev && prev->root_id == backref->root_id &&
2197             prev->inum == backref->inum &&
2198             prev->file_pos + prev->num_bytes == backref->file_pos)
2199                 merge = true;
2200
2201         /* step 1: get root */
2202         key.objectid = backref->root_id;
2203         key.type = BTRFS_ROOT_ITEM_KEY;
2204         key.offset = (u64)-1;
2205
2206         fs_info = BTRFS_I(src_inode)->root->fs_info;
2207         index = srcu_read_lock(&fs_info->subvol_srcu);
2208
2209         root = btrfs_read_fs_root_no_name(fs_info, &key);
2210         if (IS_ERR(root)) {
2211                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2212                 if (PTR_ERR(root) == -ENOENT)
2213                         return 0;
2214                 return PTR_ERR(root);
2215         }
2216
2217         /* step 2: get inode */
2218         key.objectid = backref->inum;
2219         key.type = BTRFS_INODE_ITEM_KEY;
2220         key.offset = 0;
2221
2222         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2223         if (IS_ERR(inode)) {
2224                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2225                 return 0;
2226         }
2227
2228         srcu_read_unlock(&fs_info->subvol_srcu, index);
2229
2230         /* step 3: relink backref */
2231         lock_start = backref->file_pos;
2232         lock_end = backref->file_pos + backref->num_bytes - 1;
2233         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2234                          0, &cached);
2235
2236         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2237         if (ordered) {
2238                 btrfs_put_ordered_extent(ordered);
2239                 goto out_unlock;
2240         }
2241
2242         trans = btrfs_join_transaction(root);
2243         if (IS_ERR(trans)) {
2244                 ret = PTR_ERR(trans);
2245                 goto out_unlock;
2246         }
2247
2248         key.objectid = backref->inum;
2249         key.type = BTRFS_EXTENT_DATA_KEY;
2250         key.offset = backref->file_pos;
2251
2252         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2253         if (ret < 0) {
2254                 goto out_free_path;
2255         } else if (ret > 0) {
2256                 ret = 0;
2257                 goto out_free_path;
2258         }
2259
2260         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2261                                 struct btrfs_file_extent_item);
2262
2263         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2264             backref->generation)
2265                 goto out_free_path;
2266
2267         btrfs_release_path(path);
2268
2269         start = backref->file_pos;
2270         if (backref->extent_offset < old->extent_offset + old->offset)
2271                 start += old->extent_offset + old->offset -
2272                          backref->extent_offset;
2273
2274         len = min(backref->extent_offset + backref->num_bytes,
2275                   old->extent_offset + old->offset + old->len);
2276         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2277
2278         ret = btrfs_drop_extents(trans, root, inode, start,
2279                                  start + len, 1);
2280         if (ret)
2281                 goto out_free_path;
2282 again:
2283         key.objectid = btrfs_ino(inode);
2284         key.type = BTRFS_EXTENT_DATA_KEY;
2285         key.offset = start;
2286
2287         path->leave_spinning = 1;
2288         if (merge) {
2289                 struct btrfs_file_extent_item *fi;
2290                 u64 extent_len;
2291                 struct btrfs_key found_key;
2292
2293                 ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
2294                 if (ret < 0)
2295                         goto out_free_path;
2296
2297                 path->slots[0]--;
2298                 leaf = path->nodes[0];
2299                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2300
2301                 fi = btrfs_item_ptr(leaf, path->slots[0],
2302                                     struct btrfs_file_extent_item);
2303                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2304
2305                 if (extent_len + found_key.offset == start &&
2306                     relink_is_mergable(leaf, fi, new)) {
2307                         btrfs_set_file_extent_num_bytes(leaf, fi,
2308                                                         extent_len + len);
2309                         btrfs_mark_buffer_dirty(leaf);
2310                         inode_add_bytes(inode, len);
2311
2312                         ret = 1;
2313                         goto out_free_path;
2314                 } else {
2315                         merge = false;
2316                         btrfs_release_path(path);
2317                         goto again;
2318                 }
2319         }
2320
2321         ret = btrfs_insert_empty_item(trans, root, path, &key,
2322                                         sizeof(*extent));
2323         if (ret) {
2324                 btrfs_abort_transaction(trans, root, ret);
2325                 goto out_free_path;
2326         }
2327
2328         leaf = path->nodes[0];
2329         item = btrfs_item_ptr(leaf, path->slots[0],
2330                                 struct btrfs_file_extent_item);
2331         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2332         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2333         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2334         btrfs_set_file_extent_num_bytes(leaf, item, len);
2335         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2336         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2337         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2338         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2339         btrfs_set_file_extent_encryption(leaf, item, 0);
2340         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2341
2342         btrfs_mark_buffer_dirty(leaf);
2343         inode_add_bytes(inode, len);
2344         btrfs_release_path(path);
2345
2346         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2347                         new->disk_len, 0,
2348                         backref->root_id, backref->inum,
2349                         new->file_pos, 0);      /* start - extent_offset */
2350         if (ret) {
2351                 btrfs_abort_transaction(trans, root, ret);
2352                 goto out_free_path;
2353         }
2354
2355         ret = 1;
2356 out_free_path:
2357         btrfs_release_path(path);
2358         path->leave_spinning = 0;
2359         btrfs_end_transaction(trans, root);
2360 out_unlock:
2361         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2362                              &cached, GFP_NOFS);
2363         iput(inode);
2364         return ret;
2365 }
2366
2367 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2368 {
2369         struct old_sa_defrag_extent *old, *tmp;
2370
2371         if (!new)
2372                 return;
2373
2374         list_for_each_entry_safe(old, tmp, &new->head, list) {
2375                 list_del(&old->list);
2376                 kfree(old);
2377         }
2378         kfree(new);
2379 }
2380
2381 static void relink_file_extents(struct new_sa_defrag_extent *new)
2382 {
2383         struct btrfs_path *path;
2384         struct sa_defrag_extent_backref *backref;
2385         struct sa_defrag_extent_backref *prev = NULL;
2386         struct inode *inode;
2387         struct btrfs_root *root;
2388         struct rb_node *node;
2389         int ret;
2390
2391         inode = new->inode;
2392         root = BTRFS_I(inode)->root;
2393
2394         path = btrfs_alloc_path();
2395         if (!path)
2396                 return;
2397
2398         if (!record_extent_backrefs(path, new)) {
2399                 btrfs_free_path(path);
2400                 goto out;
2401         }
2402         btrfs_release_path(path);
2403
2404         while (1) {
2405                 node = rb_first(&new->root);
2406                 if (!node)
2407                         break;
2408                 rb_erase(node, &new->root);
2409
2410                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2411
2412                 ret = relink_extent_backref(path, prev, backref);
2413                 WARN_ON(ret < 0);
2414
2415                 kfree(prev);
2416
2417                 if (ret == 1)
2418                         prev = backref;
2419                 else
2420                         prev = NULL;
2421                 cond_resched();
2422         }
2423         kfree(prev);
2424
2425         btrfs_free_path(path);
2426 out:
2427         free_sa_defrag_extent(new);
2428
2429         atomic_dec(&root->fs_info->defrag_running);
2430         wake_up(&root->fs_info->transaction_wait);
2431 }
2432
2433 static struct new_sa_defrag_extent *
2434 record_old_file_extents(struct inode *inode,
2435                         struct btrfs_ordered_extent *ordered)
2436 {
2437         struct btrfs_root *root = BTRFS_I(inode)->root;
2438         struct btrfs_path *path;
2439         struct btrfs_key key;
2440         struct old_sa_defrag_extent *old;
2441         struct new_sa_defrag_extent *new;
2442         int ret;
2443
2444         new = kmalloc(sizeof(*new), GFP_NOFS);
2445         if (!new)
2446                 return NULL;
2447
2448         new->inode = inode;
2449         new->file_pos = ordered->file_offset;
2450         new->len = ordered->len;
2451         new->bytenr = ordered->start;
2452         new->disk_len = ordered->disk_len;
2453         new->compress_type = ordered->compress_type;
2454         new->root = RB_ROOT;
2455         INIT_LIST_HEAD(&new->head);
2456
2457         path = btrfs_alloc_path();
2458         if (!path)
2459                 goto out_kfree;
2460
2461         key.objectid = btrfs_ino(inode);
2462         key.type = BTRFS_EXTENT_DATA_KEY;
2463         key.offset = new->file_pos;
2464
2465         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2466         if (ret < 0)
2467                 goto out_free_path;
2468         if (ret > 0 && path->slots[0] > 0)
2469                 path->slots[0]--;
2470
2471         /* find out all the old extents for the file range */
2472         while (1) {
2473                 struct btrfs_file_extent_item *extent;
2474                 struct extent_buffer *l;
2475                 int slot;
2476                 u64 num_bytes;
2477                 u64 offset;
2478                 u64 end;
2479                 u64 disk_bytenr;
2480                 u64 extent_offset;
2481
2482                 l = path->nodes[0];
2483                 slot = path->slots[0];
2484
2485                 if (slot >= btrfs_header_nritems(l)) {
2486                         ret = btrfs_next_leaf(root, path);
2487                         if (ret < 0)
2488                                 goto out_free_path;
2489                         else if (ret > 0)
2490                                 break;
2491                         continue;
2492                 }
2493
2494                 btrfs_item_key_to_cpu(l, &key, slot);
2495
2496                 if (key.objectid != btrfs_ino(inode))
2497                         break;
2498                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2499                         break;
2500                 if (key.offset >= new->file_pos + new->len)
2501                         break;
2502
2503                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2504
2505                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2506                 if (key.offset + num_bytes < new->file_pos)
2507                         goto next;
2508
2509                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2510                 if (!disk_bytenr)
2511                         goto next;
2512
2513                 extent_offset = btrfs_file_extent_offset(l, extent);
2514
2515                 old = kmalloc(sizeof(*old), GFP_NOFS);
2516                 if (!old)
2517                         goto out_free_path;
2518
2519                 offset = max(new->file_pos, key.offset);
2520                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2521
2522                 old->bytenr = disk_bytenr;
2523                 old->extent_offset = extent_offset;
2524                 old->offset = offset - key.offset;
2525                 old->len = end - offset;
2526                 old->new = new;
2527                 old->count = 0;
2528                 list_add_tail(&old->list, &new->head);
2529 next:
2530                 path->slots[0]++;
2531                 cond_resched();
2532         }
2533
2534         btrfs_free_path(path);
2535         atomic_inc(&root->fs_info->defrag_running);
2536
2537         return new;
2538
2539 out_free_path:
2540         btrfs_free_path(path);
2541 out_kfree:
2542         free_sa_defrag_extent(new);
2543         return NULL;
2544 }
2545
2546 /* as ordered data IO finishes, this gets called so we can finish
2547  * an ordered extent if the range of bytes in the file it covers are
2548  * fully written.
2549  */
2550 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2551 {
2552         struct inode *inode = ordered_extent->inode;
2553         struct btrfs_root *root = BTRFS_I(inode)->root;
2554         struct btrfs_trans_handle *trans = NULL;
2555         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2556         struct extent_state *cached_state = NULL;
2557         struct new_sa_defrag_extent *new = NULL;
2558         int compress_type = 0;
2559         int ret = 0;
2560         u64 logical_len = ordered_extent->len;
2561         bool nolock;
2562         bool truncated = false;
2563
2564         nolock = btrfs_is_free_space_inode(inode);
2565
2566         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2567                 ret = -EIO;
2568                 goto out;
2569         }
2570
2571         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2572                 truncated = true;
2573                 logical_len = ordered_extent->truncated_len;
2574                 /* Truncated the entire extent, don't bother adding */
2575                 if (!logical_len)
2576                         goto out;
2577         }
2578
2579         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2580                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2581                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2582                 if (nolock)
2583                         trans = btrfs_join_transaction_nolock(root);
2584                 else
2585                         trans = btrfs_join_transaction(root);
2586                 if (IS_ERR(trans)) {
2587                         ret = PTR_ERR(trans);
2588                         trans = NULL;
2589                         goto out;
2590                 }
2591                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2592                 ret = btrfs_update_inode_fallback(trans, root, inode);
2593                 if (ret) /* -ENOMEM or corruption */
2594                         btrfs_abort_transaction(trans, root, ret);
2595                 goto out;
2596         }
2597
2598         lock_extent_bits(io_tree, ordered_extent->file_offset,
2599                          ordered_extent->file_offset + ordered_extent->len - 1,
2600                          0, &cached_state);
2601
2602         ret = test_range_bit(io_tree, ordered_extent->file_offset,
2603                         ordered_extent->file_offset + ordered_extent->len - 1,
2604                         EXTENT_DEFRAG, 1, cached_state);
2605         if (ret) {
2606                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2607                 if (last_snapshot >= BTRFS_I(inode)->generation)
2608                         /* the inode is shared */
2609                         new = record_old_file_extents(inode, ordered_extent);
2610
2611                 clear_extent_bit(io_tree, ordered_extent->file_offset,
2612                         ordered_extent->file_offset + ordered_extent->len - 1,
2613                         EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS);
2614         }
2615
2616         if (nolock)
2617                 trans = btrfs_join_transaction_nolock(root);
2618         else
2619                 trans = btrfs_join_transaction(root);
2620         if (IS_ERR(trans)) {
2621                 ret = PTR_ERR(trans);
2622                 trans = NULL;
2623                 goto out_unlock;
2624         }
2625         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2626
2627         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2628                 compress_type = ordered_extent->compress_type;
2629         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2630                 BUG_ON(compress_type);
2631                 ret = btrfs_mark_extent_written(trans, inode,
2632                                                 ordered_extent->file_offset,
2633                                                 ordered_extent->file_offset +
2634                                                 logical_len);
2635         } else {
2636                 BUG_ON(root == root->fs_info->tree_root);
2637                 ret = insert_reserved_file_extent(trans, inode,
2638                                                 ordered_extent->file_offset,
2639                                                 ordered_extent->start,
2640                                                 ordered_extent->disk_len,
2641                                                 logical_len, logical_len,
2642                                                 compress_type, 0, 0,
2643                                                 BTRFS_FILE_EXTENT_REG);
2644         }
2645         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2646                            ordered_extent->file_offset, ordered_extent->len,
2647                            trans->transid);
2648         if (ret < 0) {
2649                 btrfs_abort_transaction(trans, root, ret);
2650                 goto out_unlock;
2651         }
2652
2653         add_pending_csums(trans, inode, ordered_extent->file_offset,
2654                           &ordered_extent->list);
2655
2656         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2657         ret = btrfs_update_inode_fallback(trans, root, inode);
2658         if (ret) { /* -ENOMEM or corruption */
2659                 btrfs_abort_transaction(trans, root, ret);
2660                 goto out_unlock;
2661         }
2662         ret = 0;
2663 out_unlock:
2664         unlock_extent_cached(io_tree, ordered_extent->file_offset,
2665                              ordered_extent->file_offset +
2666                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
2667 out:
2668         if (root != root->fs_info->tree_root)
2669                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
2670         if (trans)
2671                 btrfs_end_transaction(trans, root);
2672
2673         if (ret || truncated) {
2674                 u64 start, end;
2675
2676                 if (truncated)
2677                         start = ordered_extent->file_offset + logical_len;
2678                 else
2679                         start = ordered_extent->file_offset;
2680                 end = ordered_extent->file_offset + ordered_extent->len - 1;
2681                 clear_extent_uptodate(io_tree, start, end, NULL, GFP_NOFS);
2682
2683                 /* Drop the cache for the part of the extent we didn't write. */
2684                 btrfs_drop_extent_cache(inode, start, end, 0);
2685
2686                 /*
2687                  * If the ordered extent had an IOERR or something else went
2688                  * wrong we need to return the space for this ordered extent
2689                  * back to the allocator.  We only free the extent in the
2690                  * truncated case if we didn't write out the extent at all.
2691                  */
2692                 if ((ret || !logical_len) &&
2693                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2694                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
2695                         btrfs_free_reserved_extent(root, ordered_extent->start,
2696                                                    ordered_extent->disk_len);
2697         }
2698
2699
2700         /*
2701          * This needs to be done to make sure anybody waiting knows we are done
2702          * updating everything for this ordered extent.
2703          */
2704         btrfs_remove_ordered_extent(inode, ordered_extent);
2705
2706         /* for snapshot-aware defrag */
2707         if (new) {
2708                 if (ret) {
2709                         free_sa_defrag_extent(new);
2710                         atomic_dec(&root->fs_info->defrag_running);
2711                 } else {
2712                         relink_file_extents(new);
2713                 }
2714         }
2715
2716         /* once for us */
2717         btrfs_put_ordered_extent(ordered_extent);
2718         /* once for the tree */
2719         btrfs_put_ordered_extent(ordered_extent);
2720
2721         return ret;
2722 }
2723
2724 static void finish_ordered_fn(struct btrfs_work *work)
2725 {
2726         struct btrfs_ordered_extent *ordered_extent;
2727         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
2728         btrfs_finish_ordered_io(ordered_extent);
2729 }
2730
2731 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
2732                                 struct extent_state *state, int uptodate)
2733 {
2734         struct inode *inode = page->mapping->host;
2735         struct btrfs_root *root = BTRFS_I(inode)->root;
2736         struct btrfs_ordered_extent *ordered_extent = NULL;
2737         struct btrfs_workers *workers;
2738
2739         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
2740
2741         ClearPagePrivate2(page);
2742         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
2743                                             end - start + 1, uptodate))
2744                 return 0;
2745
2746         ordered_extent->work.func = finish_ordered_fn;
2747         ordered_extent->work.flags = 0;
2748
2749         if (btrfs_is_free_space_inode(inode))
2750                 workers = &root->fs_info->endio_freespace_worker;
2751         else
2752                 workers = &root->fs_info->endio_write_workers;
2753         btrfs_queue_worker(workers, &ordered_extent->work);
2754
2755         return 0;
2756 }
2757
2758 /*
2759  * when reads are done, we need to check csums to verify the data is correct
2760  * if there's a match, we allow the bio to finish.  If not, the code in
2761  * extent_io.c will try to find good copies for us.
2762  */
2763 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
2764                                       u64 phy_offset, struct page *page,
2765                                       u64 start, u64 end, int mirror)
2766 {
2767         size_t offset = start - page_offset(page);
2768         struct inode *inode = page->mapping->host;
2769         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2770         char *kaddr;
2771         struct btrfs_root *root = BTRFS_I(inode)->root;
2772         u32 csum_expected;
2773         u32 csum = ~(u32)0;
2774         static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
2775                                       DEFAULT_RATELIMIT_BURST);
2776
2777         if (PageChecked(page)) {
2778                 ClearPageChecked(page);
2779                 goto good;
2780         }
2781
2782         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
2783                 goto good;
2784
2785         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
2786             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
2787                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
2788                                   GFP_NOFS);
2789                 return 0;
2790         }
2791
2792         phy_offset >>= inode->i_sb->s_blocksize_bits;
2793         csum_expected = *(((u32 *)io_bio->csum) + phy_offset);
2794
2795         kaddr = kmap_atomic(page);
2796         csum = btrfs_csum_data(kaddr + offset, csum,  end - start + 1);
2797         btrfs_csum_final(csum, (char *)&csum);
2798         if (csum != csum_expected)
2799                 goto zeroit;
2800
2801         kunmap_atomic(kaddr);
2802 good:
2803         return 0;
2804
2805 zeroit:
2806         if (__ratelimit(&_rs))
2807                 btrfs_info(root->fs_info, "csum failed ino %llu off %llu csum %u expected csum %u",
2808                         btrfs_ino(page->mapping->host), start, csum, csum_expected);
2809         memset(kaddr + offset, 1, end - start + 1);
2810         flush_dcache_page(page);
2811         kunmap_atomic(kaddr);
2812         if (csum_expected == 0)
2813                 return 0;
2814         return -EIO;
2815 }
2816
2817 struct delayed_iput {
2818         struct list_head list;
2819         struct inode *inode;
2820 };
2821
2822 /* JDM: If this is fs-wide, why can't we add a pointer to
2823  * btrfs_inode instead and avoid the allocation? */
2824 void btrfs_add_delayed_iput(struct inode *inode)
2825 {
2826         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2827         struct delayed_iput *delayed;
2828
2829         if (atomic_add_unless(&inode->i_count, -1, 1))
2830                 return;
2831
2832         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
2833         delayed->inode = inode;
2834
2835         spin_lock(&fs_info->delayed_iput_lock);
2836         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
2837         spin_unlock(&fs_info->delayed_iput_lock);
2838 }
2839
2840 void btrfs_run_delayed_iputs(struct btrfs_root *root)
2841 {
2842         LIST_HEAD(list);
2843         struct btrfs_fs_info *fs_info = root->fs_info;
2844         struct delayed_iput *delayed;
2845         int empty;
2846
2847         spin_lock(&fs_info->delayed_iput_lock);
2848         empty = list_empty(&fs_info->delayed_iputs);
2849         spin_unlock(&fs_info->delayed_iput_lock);
2850         if (empty)
2851                 return;
2852
2853         spin_lock(&fs_info->delayed_iput_lock);
2854         list_splice_init(&fs_info->delayed_iputs, &list);
2855         spin_unlock(&fs_info->delayed_iput_lock);
2856
2857         while (!list_empty(&list)) {
2858                 delayed = list_entry(list.next, struct delayed_iput, list);
2859                 list_del(&delayed->list);
2860                 iput(delayed->inode);
2861                 kfree(delayed);
2862         }
2863 }
2864
2865 /*
2866  * This is called in transaction commit time. If there are no orphan
2867  * files in the subvolume, it removes orphan item and frees block_rsv
2868  * structure.
2869  */
2870 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
2871                               struct btrfs_root *root)
2872 {
2873         struct btrfs_block_rsv *block_rsv;
2874         int ret;
2875
2876         if (atomic_read(&root->orphan_inodes) ||
2877             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
2878                 return;
2879
2880         spin_lock(&root->orphan_lock);
2881         if (atomic_read(&root->orphan_inodes)) {
2882                 spin_unlock(&root->orphan_lock);
2883                 return;
2884         }
2885
2886         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
2887                 spin_unlock(&root->orphan_lock);
2888                 return;
2889         }
2890
2891         block_rsv = root->orphan_block_rsv;
2892         root->orphan_block_rsv = NULL;
2893         spin_unlock(&root->orphan_lock);
2894
2895         if (root->orphan_item_inserted &&
2896             btrfs_root_refs(&root->root_item) > 0) {
2897                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
2898                                             root->root_key.objectid);
2899                 if (ret)
2900                         btrfs_abort_transaction(trans, root, ret);
2901                 else
2902                         root->orphan_item_inserted = 0;
2903         }
2904
2905         if (block_rsv) {
2906                 WARN_ON(block_rsv->size > 0);
2907                 btrfs_free_block_rsv(root, block_rsv);
2908         }
2909 }
2910
2911 /*
2912  * This creates an orphan entry for the given inode in case something goes
2913  * wrong in the middle of an unlink/truncate.
2914  *
2915  * NOTE: caller of this function should reserve 5 units of metadata for
2916  *       this function.
2917  */
2918 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
2919 {
2920         struct btrfs_root *root = BTRFS_I(inode)->root;
2921         struct btrfs_block_rsv *block_rsv = NULL;
2922         int reserve = 0;
2923         int insert = 0;
2924         int ret;
2925
2926         if (!root->orphan_block_rsv) {
2927                 block_rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
2928                 if (!block_rsv)
2929                         return -ENOMEM;
2930         }
2931
2932         spin_lock(&root->orphan_lock);
2933         if (!root->orphan_block_rsv) {
2934                 root->orphan_block_rsv = block_rsv;
2935         } else if (block_rsv) {
2936                 btrfs_free_block_rsv(root, block_rsv);
2937                 block_rsv = NULL;
2938         }
2939
2940         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
2941                               &BTRFS_I(inode)->runtime_flags)) {
2942 #if 0
2943                 /*
2944                  * For proper ENOSPC handling, we should do orphan
2945                  * cleanup when mounting. But this introduces backward
2946                  * compatibility issue.
2947                  */
2948                 if (!xchg(&root->orphan_item_inserted, 1))
2949                         insert = 2;
2950                 else
2951                         insert = 1;
2952 #endif
2953                 insert = 1;
2954                 atomic_inc(&root->orphan_inodes);
2955         }
2956
2957         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
2958                               &BTRFS_I(inode)->runtime_flags))
2959                 reserve = 1;
2960         spin_unlock(&root->orphan_lock);
2961
2962         /* grab metadata reservation from transaction handle */
2963         if (reserve) {
2964                 ret = btrfs_orphan_reserve_metadata(trans, inode);
2965                 BUG_ON(ret); /* -ENOSPC in reservation; Logic error? JDM */
2966         }
2967
2968         /* insert an orphan item to track this unlinked/truncated file */
2969         if (insert >= 1) {
2970                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
2971                 if (ret) {
2972                         atomic_dec(&root->orphan_inodes);
2973                         if (reserve) {
2974                                 clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
2975                                           &BTRFS_I(inode)->runtime_flags);
2976                                 btrfs_orphan_release_metadata(inode);
2977                         }
2978                         if (ret != -EEXIST) {
2979                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
2980                                           &BTRFS_I(inode)->runtime_flags);
2981                                 btrfs_abort_transaction(trans, root, ret);
2982                                 return ret;
2983                         }
2984                 }
2985                 ret = 0;
2986         }
2987
2988         /* insert an orphan item to track subvolume contains orphan files */
2989         if (insert >= 2) {
2990                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2991                                                root->root_key.objectid);
2992                 if (ret && ret != -EEXIST) {
2993                         btrfs_abort_transaction(trans, root, ret);
2994                         return ret;
2995                 }
2996         }
2997         return 0;
2998 }
2999
3000 /*
3001  * We have done the truncate/delete so we can go ahead and remove the orphan
3002  * item for this particular inode.
3003  */
3004 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3005                             struct inode *inode)
3006 {
3007         struct btrfs_root *root = BTRFS_I(inode)->root;
3008         int delete_item = 0;
3009         int release_rsv = 0;
3010         int ret = 0;
3011
3012         spin_lock(&root->orphan_lock);
3013         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3014                                &BTRFS_I(inode)->runtime_flags))
3015                 delete_item = 1;
3016
3017         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3018                                &BTRFS_I(inode)->runtime_flags))
3019                 release_rsv = 1;
3020         spin_unlock(&root->orphan_lock);
3021
3022         if (delete_item) {
3023                 atomic_dec(&root->orphan_inodes);
3024                 if (trans)
3025                         ret = btrfs_del_orphan_item(trans, root,
3026                                                     btrfs_ino(inode));
3027         }
3028
3029         if (release_rsv)
3030                 btrfs_orphan_release_metadata(inode);
3031
3032         return ret;
3033 }
3034
3035 /*
3036  * this cleans up any orphans that may be left on the list from the last use
3037  * of this root.
3038  */
3039 int btrfs_orphan_cleanup(struct btrfs_root *root)
3040 {
3041         struct btrfs_path *path;
3042         struct extent_buffer *leaf;
3043         struct btrfs_key key, found_key;
3044         struct btrfs_trans_handle *trans;
3045         struct inode *inode;
3046         u64 last_objectid = 0;
3047         int ret = 0, nr_unlink = 0, nr_truncate = 0;
3048
3049         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3050                 return 0;
3051
3052         path = btrfs_alloc_path();
3053         if (!path) {
3054                 ret = -ENOMEM;
3055                 goto out;
3056         }
3057         path->reada = -1;
3058
3059         key.objectid = BTRFS_ORPHAN_OBJECTID;
3060         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
3061         key.offset = (u64)-1;
3062
3063         while (1) {
3064                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3065                 if (ret < 0)
3066                         goto out;
3067
3068                 /*
3069                  * if ret == 0 means we found what we were searching for, which
3070                  * is weird, but possible, so only screw with path if we didn't
3071                  * find the key and see if we have stuff that matches
3072                  */
3073                 if (ret > 0) {
3074                         ret = 0;
3075                         if (path->slots[0] == 0)
3076                                 break;
3077                         path->slots[0]--;
3078                 }
3079
3080                 /* pull out the item */
3081                 leaf = path->nodes[0];
3082                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3083
3084                 /* make sure the item matches what we want */
3085                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3086                         break;
3087                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
3088                         break;
3089
3090                 /* release the path since we're done with it */
3091                 btrfs_release_path(path);
3092
3093                 /*
3094                  * this is where we are basically btrfs_lookup, without the
3095                  * crossing root thing.  we store the inode number in the
3096                  * offset of the orphan item.
3097                  */
3098
3099                 if (found_key.offset == last_objectid) {
3100                         btrfs_err(root->fs_info,
3101                                 "Error removing orphan entry, stopping orphan cleanup");
3102                         ret = -EINVAL;
3103                         goto out;
3104                 }
3105
3106                 last_objectid = found_key.offset;
3107
3108                 found_key.objectid = found_key.offset;
3109                 found_key.type = BTRFS_INODE_ITEM_KEY;
3110                 found_key.offset = 0;
3111                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
3112                 ret = PTR_ERR_OR_ZERO(inode);
3113                 if (ret && ret != -ESTALE)
3114                         goto out;
3115
3116                 if (ret == -ESTALE && root == root->fs_info->tree_root) {
3117                         struct btrfs_root *dead_root;
3118                         struct btrfs_fs_info *fs_info = root->fs_info;
3119                         int is_dead_root = 0;
3120
3121                         /*
3122                          * this is an orphan in the tree root. Currently these
3123                          * could come from 2 sources:
3124                          *  a) a snapshot deletion in progress
3125                          *  b) a free space cache inode
3126                          * We need to distinguish those two, as the snapshot
3127                          * orphan must not get deleted.
3128                          * find_dead_roots already ran before us, so if this
3129                          * is a snapshot deletion, we should find the root
3130                          * in the dead_roots list
3131                          */
3132                         spin_lock(&fs_info->trans_lock);
3133                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3134                                             root_list) {
3135                                 if (dead_root->root_key.objectid ==
3136                                     found_key.objectid) {
3137                                         is_dead_root = 1;
3138                                         break;
3139                                 }
3140                         }
3141                         spin_unlock(&fs_info->trans_lock);
3142                         if (is_dead_root) {
3143                                 /* prevent this orphan from being found again */
3144                                 key.offset = found_key.objectid - 1;
3145                                 continue;
3146                         }
3147                 }
3148                 /*
3149                  * Inode is already gone but the orphan item is still there,
3150                  * kill the orphan item.
3151                  */
3152                 if (ret == -ESTALE) {
3153                         trans = btrfs_start_transaction(root, 1);
3154                         if (IS_ERR(trans)) {
3155                                 ret = PTR_ERR(trans);
3156                                 goto out;
3157                         }
3158                         btrfs_debug(root->fs_info, "auto deleting %Lu",
3159                                 found_key.objectid);
3160                         ret = btrfs_del_orphan_item(trans, root,
3161                                                     found_key.objectid);
3162                         btrfs_end_transaction(trans, root);
3163                         if (ret)
3164                                 goto out;
3165                         continue;
3166                 }
3167
3168                 /*
3169                  * add this inode to the orphan list so btrfs_orphan_del does
3170                  * the proper thing when we hit it
3171                  */
3172                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3173                         &BTRFS_I(inode)->runtime_flags);
3174                 atomic_inc(&root->orphan_inodes);
3175
3176                 /* if we have links, this was a truncate, lets do that */
3177                 if (inode->i_nlink) {
3178                         if (WARN_ON(!S_ISREG(inode->i_mode))) {
3179                                 iput(inode);
3180                                 continue;
3181                         }
3182                         nr_truncate++;
3183
3184                         /* 1 for the orphan item deletion. */
3185                         trans = btrfs_start_transaction(root, 1);
3186                         if (IS_ERR(trans)) {
3187                                 iput(inode);
3188                                 ret = PTR_ERR(trans);
3189                                 goto out;
3190                         }
3191                         ret = btrfs_orphan_add(trans, inode);
3192                         btrfs_end_transaction(trans, root);
3193                         if (ret) {
3194                                 iput(inode);
3195                                 goto out;
3196                         }
3197
3198                         ret = btrfs_truncate(inode);
3199                         if (ret)
3200                                 btrfs_orphan_del(NULL, inode);
3201                 } else {
3202                         nr_unlink++;
3203                 }
3204
3205                 /* this will do delete_inode and everything for us */
3206                 iput(inode);
3207                 if (ret)
3208                         goto out;
3209         }
3210         /* release the path since we're done with it */
3211         btrfs_release_path(path);
3212
3213         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3214
3215         if (root->orphan_block_rsv)
3216                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
3217                                         (u64)-1);
3218
3219         if (root->orphan_block_rsv || root->orphan_item_inserted) {
3220                 trans = btrfs_join_transaction(root);
3221                 if (!IS_ERR(trans))
3222                         btrfs_end_transaction(trans, root);
3223         }
3224
3225         if (nr_unlink)
3226                 btrfs_debug(root->fs_info, "unlinked %d orphans", nr_unlink);
3227         if (nr_truncate)
3228                 btrfs_debug(root->fs_info, "truncated %d orphans", nr_truncate);
3229
3230 out:
3231         if (ret)
3232                 btrfs_crit(root->fs_info,
3233                         "could not do orphan cleanup %d", ret);
3234         btrfs_free_path(path);
3235         return ret;
3236 }
3237
3238 /*
3239  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3240  * don't find any xattrs, we know there can't be any acls.
3241  *
3242  * slot is the slot the inode is in, objectid is the objectid of the inode
3243  */
3244 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3245                                           int slot, u64 objectid)
3246 {
3247         u32 nritems = btrfs_header_nritems(leaf);
3248         struct btrfs_key found_key;
3249         static u64 xattr_access = 0;
3250         static u64 xattr_default = 0;
3251         int scanned = 0;
3252
3253         if (!xattr_access) {
3254                 xattr_access = btrfs_name_hash(POSIX_ACL_XATTR_ACCESS,
3255                                         strlen(POSIX_ACL_XATTR_ACCESS));
3256                 xattr_default = btrfs_name_hash(POSIX_ACL_XATTR_DEFAULT,
3257                                         strlen(POSIX_ACL_XATTR_DEFAULT));
3258         }
3259
3260         slot++;
3261         while (slot < nritems) {
3262                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3263
3264                 /* we found a different objectid, there must not be acls */
3265                 if (found_key.objectid != objectid)
3266                         return 0;
3267
3268                 /* we found an xattr, assume we've got an acl */
3269                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3270                         if (found_key.offset == xattr_access ||
3271                             found_key.offset == xattr_default)
3272                                 return 1;
3273                 }
3274
3275                 /*
3276                  * we found a key greater than an xattr key, there can't
3277                  * be any acls later on
3278                  */
3279                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3280                         return 0;
3281
3282                 slot++;
3283                 scanned++;
3284
3285                 /*
3286                  * it goes inode, inode backrefs, xattrs, extents,
3287                  * so if there are a ton of hard links to an inode there can
3288                  * be a lot of backrefs.  Don't waste time searching too hard,
3289                  * this is just an optimization
3290                  */
3291                 if (scanned >= 8)
3292                         break;
3293         }
3294         /* we hit the end of the leaf before we found an xattr or
3295          * something larger than an xattr.  We have to assume the inode
3296          * has acls
3297          */
3298         return 1;
3299 }
3300
3301 /*
3302  * read an inode from the btree into the in-memory inode
3303  */
3304 static void btrfs_read_locked_inode(struct inode *inode)
3305 {
3306         struct btrfs_path *path;
3307         struct extent_buffer *leaf;
3308         struct btrfs_inode_item *inode_item;
3309         struct btrfs_timespec *tspec;
3310         struct btrfs_root *root = BTRFS_I(inode)->root;
3311         struct btrfs_key location;
3312         unsigned long ptr;
3313         int maybe_acls;
3314         u32 rdev;
3315         int ret;
3316         bool filled = false;
3317
3318         ret = btrfs_fill_inode(inode, &rdev);
3319         if (!ret)
3320                 filled = true;
3321
3322         path = btrfs_alloc_path();
3323         if (!path)
3324                 goto make_bad;
3325
3326         path->leave_spinning = 1;
3327         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3328
3329         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3330         if (ret)
3331                 goto make_bad;
3332
3333         leaf = path->nodes[0];
3334
3335         if (filled)
3336                 goto cache_index;
3337
3338         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3339                                     struct btrfs_inode_item);
3340         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3341         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3342         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3343         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3344         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
3345
3346         tspec = btrfs_inode_atime(inode_item);
3347         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3348         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3349
3350         tspec = btrfs_inode_mtime(inode_item);
3351         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3352         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3353
3354         tspec = btrfs_inode_ctime(inode_item);
3355         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3356         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3357
3358         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3359         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3360         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3361
3362         /*
3363          * If we were modified in the current generation and evicted from memory
3364          * and then re-read we need to do a full sync since we don't have any
3365          * idea about which extents were modified before we were evicted from
3366          * cache.
3367          */
3368         if (BTRFS_I(inode)->last_trans == root->fs_info->generation)
3369                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3370                         &BTRFS_I(inode)->runtime_flags);
3371
3372         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
3373         inode->i_generation = BTRFS_I(inode)->generation;
3374         inode->i_rdev = 0;
3375         rdev = btrfs_inode_rdev(leaf, inode_item);
3376
3377         BTRFS_I(inode)->index_cnt = (u64)-1;
3378         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3379
3380 cache_index:
3381         path->slots[0]++;
3382         if (inode->i_nlink != 1 ||
3383             path->slots[0] >= btrfs_header_nritems(leaf))
3384                 goto cache_acl;
3385
3386         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3387         if (location.objectid != btrfs_ino(inode))
3388                 goto cache_acl;
3389
3390         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3391         if (location.type == BTRFS_INODE_REF_KEY) {
3392                 struct btrfs_inode_ref *ref;
3393
3394                 ref = (struct btrfs_inode_ref *)ptr;
3395                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3396         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3397                 struct btrfs_inode_extref *extref;
3398
3399                 extref = (struct btrfs_inode_extref *)ptr;
3400                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3401                                                                      extref);
3402         }
3403 cache_acl:
3404         /*
3405          * try to precache a NULL acl entry for files that don't have
3406          * any xattrs or acls
3407          */
3408         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3409                                            btrfs_ino(inode));
3410         if (!maybe_acls)
3411                 cache_no_acl(inode);
3412
3413         btrfs_free_path(path);
3414
3415         switch (inode->i_mode & S_IFMT) {
3416         case S_IFREG:
3417                 inode->i_mapping->a_ops = &btrfs_aops;
3418                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3419                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3420                 inode->i_fop = &btrfs_file_operations;
3421                 inode->i_op = &btrfs_file_inode_operations;
3422                 break;
3423         case S_IFDIR:
3424                 inode->i_fop = &btrfs_dir_file_operations;
3425                 if (root == root->fs_info->tree_root)
3426                         inode->i_op = &btrfs_dir_ro_inode_operations;
3427                 else
3428                         inode->i_op = &btrfs_dir_inode_operations;
3429                 break;
3430         case S_IFLNK:
3431                 inode->i_op = &btrfs_symlink_inode_operations;
3432                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3433                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3434                 break;
3435         default:
3436                 inode->i_op = &btrfs_special_inode_operations;
3437                 init_special_inode(inode, inode->i_mode, rdev);
3438                 break;
3439         }
3440
3441         btrfs_update_iflags(inode);
3442         return;
3443
3444 make_bad:
3445         btrfs_free_path(path);
3446         make_bad_inode(inode);
3447 }
3448
3449 /*
3450  * given a leaf and an inode, copy the inode fields into the leaf
3451  */
3452 static void fill_inode_item(struct btrfs_trans_handle *trans,
3453                             struct extent_buffer *leaf,
3454                             struct btrfs_inode_item *item,
3455                             struct inode *inode)
3456 {
3457         struct btrfs_map_token token;
3458
3459         btrfs_init_map_token(&token);
3460
3461         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3462         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3463         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3464                                    &token);
3465         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3466         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3467
3468         btrfs_set_token_timespec_sec(leaf, btrfs_inode_atime(item),
3469                                      inode->i_atime.tv_sec, &token);
3470         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_atime(item),
3471                                       inode->i_atime.tv_nsec, &token);
3472
3473         btrfs_set_token_timespec_sec(leaf, btrfs_inode_mtime(item),
3474                                      inode->i_mtime.tv_sec, &token);
3475         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_mtime(item),
3476                                       inode->i_mtime.tv_nsec, &token);
3477
3478         btrfs_set_token_timespec_sec(leaf, btrfs_inode_ctime(item),
3479                                      inode->i_ctime.tv_sec, &token);
3480         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_ctime(item),
3481                                       inode->i_ctime.tv_nsec, &token);
3482
3483         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3484                                      &token);
3485         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3486                                          &token);
3487         btrfs_set_token_inode_sequence(leaf, item, inode->i_version, &token);
3488         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3489         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3490         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3491         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3492 }
3493
3494 /*
3495  * copy everything in the in-memory inode into the btree.
3496  */
3497 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3498                                 struct btrfs_root *root, struct inode *inode)
3499 {
3500         struct btrfs_inode_item *inode_item;
3501         struct btrfs_path *path;
3502         struct extent_buffer *leaf;
3503         int ret;
3504
3505         path = btrfs_alloc_path();
3506         if (!path)
3507                 return -ENOMEM;
3508
3509         path->leave_spinning = 1;
3510         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3511                                  1);
3512         if (ret) {
3513                 if (ret > 0)
3514                         ret = -ENOENT;
3515                 goto failed;
3516         }
3517
3518         btrfs_unlock_up_safe(path, 1);
3519         leaf = path->nodes[0];
3520         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3521                                     struct btrfs_inode_item);
3522
3523         fill_inode_item(trans, leaf, inode_item, inode);
3524         btrfs_mark_buffer_dirty(leaf);
3525         btrfs_set_inode_last_trans(trans, inode);
3526         ret = 0;
3527 failed:
3528         btrfs_free_path(path);
3529         return ret;
3530 }
3531
3532 /*
3533  * copy everything in the in-memory inode into the btree.
3534  */
3535 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3536                                 struct btrfs_root *root, struct inode *inode)
3537 {
3538         int ret;
3539
3540         /*
3541          * If the inode is a free space inode, we can deadlock during commit
3542          * if we put it into the delayed code.
3543          *
3544          * The data relocation inode should also be directly updated
3545          * without delay
3546          */
3547         if (!btrfs_is_free_space_inode(inode)
3548             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID) {
3549                 btrfs_update_root_times(trans, root);
3550
3551                 ret = btrfs_delayed_update_inode(trans, root, inode);
3552                 if (!ret)
3553                         btrfs_set_inode_last_trans(trans, inode);
3554                 return ret;
3555         }
3556
3557         return btrfs_update_inode_item(trans, root, inode);
3558 }
3559
3560 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3561                                          struct btrfs_root *root,
3562                                          struct inode *inode)
3563 {
3564         int ret;
3565
3566         ret = btrfs_update_inode(trans, root, inode);
3567         if (ret == -ENOSPC)
3568                 return btrfs_update_inode_item(trans, root, inode);
3569         return ret;
3570 }
3571
3572 /*
3573  * unlink helper that gets used here in inode.c and in the tree logging
3574  * recovery code.  It remove a link in a directory with a given name, and
3575  * also drops the back refs in the inode to the directory
3576  */
3577 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3578                                 struct btrfs_root *root,
3579                                 struct inode *dir, struct inode *inode,
3580                                 const char *name, int name_len)
3581 {
3582         struct btrfs_path *path;
3583         int ret = 0;
3584         struct extent_buffer *leaf;
3585         struct btrfs_dir_item *di;
3586         struct btrfs_key key;
3587         u64 index;
3588         u64 ino = btrfs_ino(inode);
3589         u64 dir_ino = btrfs_ino(dir);
3590
3591         path = btrfs_alloc_path();
3592         if (!path) {
3593                 ret = -ENOMEM;
3594                 goto out;
3595         }
3596
3597         path->leave_spinning = 1;
3598         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3599                                     name, name_len, -1);
3600         if (IS_ERR(di)) {
3601                 ret = PTR_ERR(di);
3602                 goto err;
3603         }
3604         if (!di) {
3605                 ret = -ENOENT;
3606                 goto err;
3607         }
3608         leaf = path->nodes[0];
3609         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3610         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3611         if (ret)
3612                 goto err;
3613         btrfs_release_path(path);
3614
3615         /*
3616          * If we don't have dir index, we have to get it by looking up
3617          * the inode ref, since we get the inode ref, remove it directly,
3618          * it is unnecessary to do delayed deletion.
3619          *
3620          * But if we have dir index, needn't search inode ref to get it.
3621          * Since the inode ref is close to the inode item, it is better
3622          * that we delay to delete it, and just do this deletion when
3623          * we update the inode item.
3624          */
3625         if (BTRFS_I(inode)->dir_index) {
3626                 ret = btrfs_delayed_delete_inode_ref(inode);
3627                 if (!ret) {
3628                         index = BTRFS_I(inode)->dir_index;
3629                         goto skip_backref;
3630                 }
3631         }
3632
3633         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3634                                   dir_ino, &index);
3635         if (ret) {
3636                 btrfs_info(root->fs_info,
3637                         "failed to delete reference to %.*s, inode %llu parent %llu",
3638                         name_len, name, ino, dir_ino);
3639                 btrfs_abort_transaction(trans, root, ret);
3640                 goto err;
3641         }
3642 skip_backref:
3643         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3644         if (ret) {
3645                 btrfs_abort_transaction(trans, root, ret);
3646                 goto err;
3647         }
3648
3649         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
3650                                          inode, dir_ino);
3651         if (ret != 0 && ret != -ENOENT) {
3652                 btrfs_abort_transaction(trans, root, ret);
3653                 goto err;
3654         }
3655
3656         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
3657                                            dir, index);
3658         if (ret == -ENOENT)
3659                 ret = 0;
3660         else if (ret)
3661                 btrfs_abort_transaction(trans, root, ret);
3662 err:
3663         btrfs_free_path(path);
3664         if (ret)
3665                 goto out;
3666
3667         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3668         inode_inc_iversion(inode);
3669         inode_inc_iversion(dir);
3670         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3671         ret = btrfs_update_inode(trans, root, dir);
3672 out:
3673         return ret;
3674 }
3675
3676 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3677                        struct btrfs_root *root,
3678                        struct inode *dir, struct inode *inode,
3679                        const char *name, int name_len)
3680 {
3681         int ret;
3682         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
3683         if (!ret) {
3684                 drop_nlink(inode);
3685                 ret = btrfs_update_inode(trans, root, inode);
3686         }
3687         return ret;
3688 }
3689
3690 /*
3691  * helper to start transaction for unlink and rmdir.
3692  *
3693  * unlink and rmdir are special in btrfs, they do not always free space, so
3694  * if we cannot make our reservations the normal way try and see if there is
3695  * plenty of slack room in the global reserve to migrate, otherwise we cannot
3696  * allow the unlink to occur.
3697  */
3698 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
3699 {
3700         struct btrfs_trans_handle *trans;
3701         struct btrfs_root *root = BTRFS_I(dir)->root;
3702         int ret;
3703
3704         /*
3705          * 1 for the possible orphan item
3706          * 1 for the dir item
3707          * 1 for the dir index
3708          * 1 for the inode ref
3709          * 1 for the inode
3710          */
3711         trans = btrfs_start_transaction(root, 5);
3712         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
3713                 return trans;
3714
3715         if (PTR_ERR(trans) == -ENOSPC) {
3716                 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
3717
3718                 trans = btrfs_start_transaction(root, 0);
3719                 if (IS_ERR(trans))
3720                         return trans;
3721                 ret = btrfs_cond_migrate_bytes(root->fs_info,
3722                                                &root->fs_info->trans_block_rsv,
3723                                                num_bytes, 5);
3724                 if (ret) {
3725                         btrfs_end_transaction(trans, root);
3726                         return ERR_PTR(ret);
3727                 }
3728                 trans->block_rsv = &root->fs_info->trans_block_rsv;
3729                 trans->bytes_reserved = num_bytes;
3730         }
3731         return trans;
3732 }
3733
3734 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
3735 {
3736         struct btrfs_root *root = BTRFS_I(dir)->root;
3737         struct btrfs_trans_handle *trans;
3738         struct inode *inode = dentry->d_inode;
3739         int ret;
3740
3741         trans = __unlink_start_trans(dir);
3742         if (IS_ERR(trans))
3743                 return PTR_ERR(trans);
3744
3745         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
3746
3747         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3748                                  dentry->d_name.name, dentry->d_name.len);
3749         if (ret)
3750                 goto out;
3751
3752         if (inode->i_nlink == 0) {
3753                 ret = btrfs_orphan_add(trans, inode);
3754                 if (ret)
3755                         goto out;
3756         }
3757
3758 out:
3759         btrfs_end_transaction(trans, root);
3760         btrfs_btree_balance_dirty(root);
3761         return ret;
3762 }
3763
3764 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
3765                         struct btrfs_root *root,
3766                         struct inode *dir, u64 objectid,
3767                         const char *name, int name_len)
3768 {
3769         struct btrfs_path *path;
3770         struct extent_buffer *leaf;
3771         struct btrfs_dir_item *di;
3772         struct btrfs_key key;
3773         u64 index;
3774         int ret;
3775         u64 dir_ino = btrfs_ino(dir);
3776
3777         path = btrfs_alloc_path();
3778         if (!path)
3779                 return -ENOMEM;
3780
3781         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3782                                    name, name_len, -1);
3783         if (IS_ERR_OR_NULL(di)) {
3784                 if (!di)
3785                         ret = -ENOENT;
3786                 else
3787                         ret = PTR_ERR(di);
3788                 goto out;
3789         }
3790
3791         leaf = path->nodes[0];
3792         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3793         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3794         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3795         if (ret) {
3796                 btrfs_abort_transaction(trans, root, ret);
3797                 goto out;
3798         }
3799         btrfs_release_path(path);
3800
3801         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3802                                  objectid, root->root_key.objectid,
3803                                  dir_ino, &index, name, name_len);
3804         if (ret < 0) {
3805                 if (ret != -ENOENT) {
3806                         btrfs_abort_transaction(trans, root, ret);
3807                         goto out;
3808                 }
3809                 di = btrfs_search_dir_index_item(root, path, dir_ino,
3810                                                  name, name_len);
3811                 if (IS_ERR_OR_NULL(di)) {
3812                         if (!di)
3813                                 ret = -ENOENT;
3814                         else
3815                                 ret = PTR_ERR(di);
3816                         btrfs_abort_transaction(trans, root, ret);
3817                         goto out;
3818                 }
3819
3820                 leaf = path->nodes[0];
3821                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3822                 btrfs_release_path(path);
3823                 index = key.offset;
3824         }
3825         btrfs_release_path(path);
3826
3827         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3828         if (ret) {
3829                 btrfs_abort_transaction(trans, root, ret);
3830                 goto out;
3831         }
3832
3833         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3834         inode_inc_iversion(dir);
3835         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3836         ret = btrfs_update_inode_fallback(trans, root, dir);
3837         if (ret)
3838                 btrfs_abort_transaction(trans, root, ret);
3839 out:
3840         btrfs_free_path(path);
3841         return ret;
3842 }
3843
3844 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
3845 {
3846         struct inode *inode = dentry->d_inode;
3847         int err = 0;
3848         struct btrfs_root *root = BTRFS_I(dir)->root;
3849         struct btrfs_trans_handle *trans;
3850
3851         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
3852                 return -ENOTEMPTY;
3853         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
3854                 return -EPERM;
3855
3856         trans = __unlink_start_trans(dir);
3857         if (IS_ERR(trans))
3858                 return PTR_ERR(trans);
3859
3860         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
3861                 err = btrfs_unlink_subvol(trans, root, dir,
3862                                           BTRFS_I(inode)->location.objectid,
3863                                           dentry->d_name.name,
3864                                           dentry->d_name.len);
3865                 goto out;
3866         }
3867
3868         err = btrfs_orphan_add(trans, inode);
3869         if (err)
3870                 goto out;
3871
3872         /* now the directory is empty */
3873         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3874                                  dentry->d_name.name, dentry->d_name.len);
3875         if (!err)
3876                 btrfs_i_size_write(inode, 0);
3877 out:
3878         btrfs_end_transaction(trans, root);
3879         btrfs_btree_balance_dirty(root);
3880
3881         return err;
3882 }
3883
3884 /*
3885  * this can truncate away extent items, csum items and directory items.
3886  * It starts at a high offset and removes keys until it can't find
3887  * any higher than new_size
3888  *
3889  * csum items that cross the new i_size are truncated to the new size
3890  * as well.
3891  *
3892  * min_type is the minimum key type to truncate down to.  If set to 0, this
3893  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3894  */
3895 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
3896                                struct btrfs_root *root,
3897                                struct inode *inode,
3898                                u64 new_size, u32 min_type)
3899 {
3900         struct btrfs_path *path;
3901         struct extent_buffer *leaf;
3902         struct btrfs_file_extent_item *fi;
3903         struct btrfs_key key;
3904         struct btrfs_key found_key;
3905         u64 extent_start = 0;
3906         u64 extent_num_bytes = 0;
3907         u64 extent_offset = 0;
3908         u64 item_end = 0;
3909         u64 last_size = (u64)-1;
3910         u32 found_type = (u8)-1;
3911         int found_extent;
3912         int del_item;
3913         int pending_del_nr = 0;
3914         int pending_del_slot = 0;
3915         int extent_type = -1;
3916         int ret;
3917         int err = 0;
3918         u64 ino = btrfs_ino(inode);
3919
3920         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
3921
3922         path = btrfs_alloc_path();
3923         if (!path)
3924                 return -ENOMEM;
3925         path->reada = -1;
3926
3927         /*
3928          * We want to drop from the next block forward in case this new size is
3929          * not block aligned since we will be keeping the last block of the
3930          * extent just the way it is.
3931          */
3932         if (root->ref_cows || root == root->fs_info->tree_root)
3933                 btrfs_drop_extent_cache(inode, ALIGN(new_size,
3934                                         root->sectorsize), (u64)-1, 0);
3935
3936         /*
3937          * This function is also used to drop the items in the log tree before
3938          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
3939          * it is used to drop the loged items. So we shouldn't kill the delayed
3940          * items.
3941          */
3942         if (min_type == 0 && root == BTRFS_I(inode)->root)
3943                 btrfs_kill_delayed_inode_items(inode);
3944
3945         key.objectid = ino;
3946         key.offset = (u64)-1;
3947         key.type = (u8)-1;
3948
3949 search_again:
3950         path->leave_spinning = 1;
3951         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3952         if (ret < 0) {
3953                 err = ret;
3954                 goto out;
3955         }
3956
3957         if (ret > 0) {
3958                 /* there are no items in the tree for us to truncate, we're
3959                  * done
3960                  */
3961                 if (path->slots[0] == 0)
3962                         goto out;
3963                 path->slots[0]--;
3964         }
3965
3966         while (1) {
3967                 fi = NULL;
3968                 leaf = path->nodes[0];
3969                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3970                 found_type = btrfs_key_type(&found_key);
3971
3972                 if (found_key.objectid != ino)
3973                         break;
3974
3975                 if (found_type < min_type)
3976                         break;
3977
3978                 item_end = found_key.offset;
3979                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
3980                         fi = btrfs_item_ptr(leaf, path->slots[0],
3981                                             struct btrfs_file_extent_item);
3982                         extent_type = btrfs_file_extent_type(leaf, fi);
3983                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3984                                 item_end +=
3985                                     btrfs_file_extent_num_bytes(leaf, fi);
3986                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3987                                 item_end += btrfs_file_extent_inline_len(leaf,
3988                                                                          fi);
3989                         }
3990                         item_end--;
3991                 }
3992                 if (found_type > min_type) {
3993                         del_item = 1;
3994                 } else {
3995                         if (item_end < new_size)
3996                                 break;
3997                         if (found_key.offset >= new_size)
3998                                 del_item = 1;
3999                         else
4000                                 del_item = 0;
4001                 }
4002                 found_extent = 0;
4003                 /* FIXME, shrink the extent if the ref count is only 1 */
4004                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4005                         goto delete;
4006
4007                 if (del_item)
4008                         last_size = found_key.offset;
4009                 else
4010                         last_size = new_size;
4011
4012                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4013                         u64 num_dec;
4014                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4015                         if (!del_item) {
4016                                 u64 orig_num_bytes =
4017                                         btrfs_file_extent_num_bytes(leaf, fi);
4018                                 extent_num_bytes = ALIGN(new_size -
4019                                                 found_key.offset,
4020                                                 root->sectorsize);
4021                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4022                                                          extent_num_bytes);
4023                                 num_dec = (orig_num_bytes -
4024                                            extent_num_bytes);
4025                                 if (root->ref_cows && extent_start != 0)
4026                                         inode_sub_bytes(inode, num_dec);
4027                                 btrfs_mark_buffer_dirty(leaf);
4028                         } else {
4029                                 extent_num_bytes =
4030                                         btrfs_file_extent_disk_num_bytes(leaf,
4031                                                                          fi);
4032                                 extent_offset = found_key.offset -
4033                                         btrfs_file_extent_offset(leaf, fi);
4034
4035                                 /* FIXME blocksize != 4096 */
4036                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4037                                 if (extent_start != 0) {
4038                                         found_extent = 1;
4039                                         if (root->ref_cows)
4040                                                 inode_sub_bytes(inode, num_dec);
4041                                 }
4042                         }
4043                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4044                         /*
4045                          * we can't truncate inline items that have had
4046                          * special encodings
4047                          */
4048                         if (!del_item &&
4049                             btrfs_file_extent_compression(leaf, fi) == 0 &&
4050                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4051                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
4052                                 u32 size = new_size - found_key.offset;
4053
4054                                 if (root->ref_cows) {
4055                                         inode_sub_bytes(inode, item_end + 1 -
4056                                                         new_size);
4057                                 }
4058                                 size =
4059                                     btrfs_file_extent_calc_inline_size(size);
4060                                 btrfs_truncate_item(root, path, size, 1);
4061                         } else if (root->ref_cows) {
4062                                 inode_sub_bytes(inode, item_end + 1 -
4063                                                 found_key.offset);
4064                         }
4065                 }
4066 delete:
4067                 if (del_item) {
4068                         if (!pending_del_nr) {
4069                                 /* no pending yet, add ourselves */
4070                                 pending_del_slot = path->slots[0];
4071                                 pending_del_nr = 1;
4072                         } else if (pending_del_nr &&
4073                                    path->slots[0] + 1 == pending_del_slot) {
4074                                 /* hop on the pending chunk */
4075                                 pending_del_nr++;
4076                                 pending_del_slot = path->slots[0];
4077                         } else {
4078                                 BUG();
4079                         }
4080                 } else {
4081                         break;
4082                 }
4083                 if (found_extent && (root->ref_cows ||
4084                                      root == root->fs_info->tree_root)) {
4085                         btrfs_set_path_blocking(path);
4086                         ret = btrfs_free_extent(trans, root, extent_start,
4087                                                 extent_num_bytes, 0,
4088                                                 btrfs_header_owner(leaf),
4089                                                 ino, extent_offset, 0);
4090                         BUG_ON(ret);
4091                 }
4092
4093                 if (found_type == BTRFS_INODE_ITEM_KEY)
4094                         break;
4095
4096                 if (path->slots[0] == 0 ||
4097                     path->slots[0] != pending_del_slot) {
4098                         if (pending_del_nr) {
4099                                 ret = btrfs_del_items(trans, root, path,
4100                                                 pending_del_slot,
4101                                                 pending_del_nr);
4102                                 if (ret) {
4103                                         btrfs_abort_transaction(trans,
4104                                                                 root, ret);
4105                                         goto error;
4106                                 }
4107                                 pending_del_nr = 0;
4108                         }
4109                         btrfs_release_path(path);
4110                         goto search_again;
4111                 } else {
4112                         path->slots[0]--;
4113                 }
4114         }
4115 out:
4116         if (pending_del_nr) {
4117                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
4118                                       pending_del_nr);
4119                 if (ret)
4120                         btrfs_abort_transaction(trans, root, ret);
4121         }
4122 error:
4123         if (last_size != (u64)-1)
4124                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4125         btrfs_free_path(path);
4126         return err;
4127 }
4128
4129 /*
4130  * btrfs_truncate_page - read, zero a chunk and write a page
4131  * @inode - inode that we're zeroing
4132  * @from - the offset to start zeroing
4133  * @len - the length to zero, 0 to zero the entire range respective to the
4134  *      offset
4135  * @front - zero up to the offset instead of from the offset on
4136  *
4137  * This will find the page for the "from" offset and cow the page and zero the
4138  * part we want to zero.  This is used with truncate and hole punching.
4139  */
4140 int btrfs_truncate_page(struct inode *inode, loff_t from, loff_t len,
4141                         int front)
4142 {
4143         struct address_space *mapping = inode->i_mapping;
4144         struct btrfs_root *root = BTRFS_I(inode)->root;
4145         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4146         struct btrfs_ordered_extent *ordered;
4147         struct extent_state *cached_state = NULL;
4148         char *kaddr;
4149         u32 blocksize = root->sectorsize;
4150         pgoff_t index = from >> PAGE_CACHE_SHIFT;
4151         unsigned offset = from & (PAGE_CACHE_SIZE-1);
4152         struct page *page;
4153         gfp_t mask = btrfs_alloc_write_mask(mapping);
4154         int ret = 0;
4155         u64 page_start;
4156         u64 page_end;
4157
4158         if ((offset & (blocksize - 1)) == 0 &&
4159             (!len || ((len & (blocksize - 1)) == 0)))
4160                 goto out;
4161         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
4162         if (ret)
4163                 goto out;
4164
4165 again:
4166         page = find_or_create_page(mapping, index, mask);
4167         if (!page) {
4168                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4169                 ret = -ENOMEM;
4170                 goto out;
4171         }
4172
4173         page_start = page_offset(page);
4174         page_end = page_start + PAGE_CACHE_SIZE - 1;
4175
4176         if (!PageUptodate(page)) {
4177                 ret = btrfs_readpage(NULL, page);
4178                 lock_page(page);
4179                 if (page->mapping != mapping) {
4180                         unlock_page(page);
4181                         page_cache_release(page);
4182                         goto again;
4183                 }
4184                 if (!PageUptodate(page)) {
4185                         ret = -EIO;
4186                         goto out_unlock;
4187                 }
4188         }
4189         wait_on_page_writeback(page);
4190
4191         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
4192         set_page_extent_mapped(page);
4193
4194         ordered = btrfs_lookup_ordered_extent(inode, page_start);
4195         if (ordered) {
4196                 unlock_extent_cached(io_tree, page_start, page_end,
4197                                      &cached_state, GFP_NOFS);
4198                 unlock_page(page);
4199                 page_cache_release(page);
4200                 btrfs_start_ordered_extent(inode, ordered, 1);
4201                 btrfs_put_ordered_extent(ordered);
4202                 goto again;
4203         }
4204
4205         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
4206                           EXTENT_DIRTY | EXTENT_DELALLOC |
4207                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4208                           0, 0, &cached_state, GFP_NOFS);
4209
4210         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
4211                                         &cached_state);
4212         if (ret) {
4213                 unlock_extent_cached(io_tree, page_start, page_end,
4214                                      &cached_state, GFP_NOFS);
4215                 goto out_unlock;
4216         }
4217
4218         if (offset != PAGE_CACHE_SIZE) {
4219                 if (!len)
4220                         len = PAGE_CACHE_SIZE - offset;
4221                 kaddr = kmap(page);
4222                 if (front)
4223                         memset(kaddr, 0, offset);
4224                 else
4225                         memset(kaddr + offset, 0, len);
4226                 flush_dcache_page(page);
4227                 kunmap(page);
4228         }
4229         ClearPageChecked(page);
4230         set_page_dirty(page);
4231         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
4232                              GFP_NOFS);
4233
4234 out_unlock:
4235         if (ret)
4236                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4237         unlock_page(page);
4238         page_cache_release(page);
4239 out:
4240         return ret;
4241 }
4242
4243 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4244                              u64 offset, u64 len)
4245 {
4246         struct btrfs_trans_handle *trans;
4247         int ret;
4248
4249         /*
4250          * Still need to make sure the inode looks like it's been updated so
4251          * that any holes get logged if we fsync.
4252          */
4253         if (btrfs_fs_incompat(root->fs_info, NO_HOLES)) {
4254                 BTRFS_I(inode)->last_trans = root->fs_info->generation;
4255                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4256                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4257                 return 0;
4258         }
4259
4260         /*
4261          * 1 - for the one we're dropping
4262          * 1 - for the one we're adding
4263          * 1 - for updating the inode.
4264          */
4265         trans = btrfs_start_transaction(root, 3);
4266         if (IS_ERR(trans))
4267                 return PTR_ERR(trans);
4268
4269         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4270         if (ret) {
4271                 btrfs_abort_transaction(trans, root, ret);
4272                 btrfs_end_transaction(trans, root);
4273                 return ret;
4274         }
4275
4276         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
4277                                        0, 0, len, 0, len, 0, 0, 0);
4278         if (ret)
4279                 btrfs_abort_transaction(trans, root, ret);
4280         else
4281                 btrfs_update_inode(trans, root, inode);
4282         btrfs_end_transaction(trans, root);
4283         return ret;
4284 }
4285
4286 /*
4287  * This function puts in dummy file extents for the area we're creating a hole
4288  * for.  So if we are truncating this file to a larger size we need to insert
4289  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4290  * the range between oldsize and size
4291  */
4292 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4293 {
4294         struct btrfs_root *root = BTRFS_I(inode)->root;
4295         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4296         struct extent_map *em = NULL;
4297         struct extent_state *cached_state = NULL;
4298         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4299         u64 hole_start = ALIGN(oldsize, root->sectorsize);
4300         u64 block_end = ALIGN(size, root->sectorsize);
4301         u64 last_byte;
4302         u64 cur_offset;
4303         u64 hole_size;
4304         int err = 0;
4305
4306         /*
4307          * If our size started in the middle of a page we need to zero out the
4308          * rest of the page before we expand the i_size, otherwise we could
4309          * expose stale data.
4310          */
4311         err = btrfs_truncate_page(inode, oldsize, 0, 0);
4312         if (err)
4313                 return err;
4314
4315         if (size <= hole_start)
4316                 return 0;
4317
4318         while (1) {
4319                 struct btrfs_ordered_extent *ordered;
4320
4321                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
4322                                  &cached_state);
4323                 ordered = btrfs_lookup_ordered_range(inode, hole_start,
4324                                                      block_end - hole_start);
4325                 if (!ordered)
4326                         break;
4327                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
4328                                      &cached_state, GFP_NOFS);
4329                 btrfs_start_ordered_extent(inode, ordered, 1);
4330                 btrfs_put_ordered_extent(ordered);
4331         }
4332
4333         cur_offset = hole_start;
4334         while (1) {
4335                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
4336                                 block_end - cur_offset, 0);
4337                 if (IS_ERR(em)) {
4338                         err = PTR_ERR(em);
4339                         em = NULL;
4340                         break;
4341                 }
4342                 last_byte = min(extent_map_end(em), block_end);
4343                 last_byte = ALIGN(last_byte , root->sectorsize);
4344                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4345                         struct extent_map *hole_em;
4346                         hole_size = last_byte - cur_offset;
4347
4348                         err = maybe_insert_hole(root, inode, cur_offset,
4349                                                 hole_size);
4350                         if (err)
4351                                 break;
4352                         btrfs_drop_extent_cache(inode, cur_offset,
4353                                                 cur_offset + hole_size - 1, 0);
4354                         hole_em = alloc_extent_map();
4355                         if (!hole_em) {
4356                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4357                                         &BTRFS_I(inode)->runtime_flags);
4358                                 goto next;
4359                         }
4360                         hole_em->start = cur_offset;
4361                         hole_em->len = hole_size;
4362                         hole_em->orig_start = cur_offset;
4363
4364                         hole_em->block_start = EXTENT_MAP_HOLE;
4365                         hole_em->block_len = 0;
4366                         hole_em->orig_block_len = 0;
4367                         hole_em->ram_bytes = hole_size;
4368                         hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
4369                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4370                         hole_em->generation = root->fs_info->generation;
4371
4372                         while (1) {
4373                                 write_lock(&em_tree->lock);
4374                                 err = add_extent_mapping(em_tree, hole_em, 1);
4375                                 write_unlock(&em_tree->lock);
4376                                 if (err != -EEXIST)
4377                                         break;
4378                                 btrfs_drop_extent_cache(inode, cur_offset,
4379                                                         cur_offset +
4380                                                         hole_size - 1, 0);
4381                         }
4382                         free_extent_map(hole_em);
4383                 }
4384 next:
4385                 free_extent_map(em);
4386                 em = NULL;
4387                 cur_offset = last_byte;
4388                 if (cur_offset >= block_end)
4389                         break;
4390         }
4391         free_extent_map(em);
4392         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
4393                              GFP_NOFS);
4394         return err;
4395 }
4396
4397 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4398 {
4399         struct btrfs_root *root = BTRFS_I(inode)->root;
4400         struct btrfs_trans_handle *trans;
4401         loff_t oldsize = i_size_read(inode);
4402         loff_t newsize = attr->ia_size;
4403         int mask = attr->ia_valid;
4404         int ret;
4405
4406         /*
4407          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4408          * special case where we need to update the times despite not having
4409          * these flags set.  For all other operations the VFS set these flags
4410          * explicitly if it wants a timestamp update.
4411          */
4412         if (newsize != oldsize && (!(mask & (ATTR_CTIME | ATTR_MTIME))))
4413                 inode->i_ctime = inode->i_mtime = current_fs_time(inode->i_sb);
4414
4415         if (newsize > oldsize) {
4416                 truncate_pagecache(inode, newsize);
4417                 ret = btrfs_cont_expand(inode, oldsize, newsize);
4418                 if (ret)
4419                         return ret;
4420
4421                 trans = btrfs_start_transaction(root, 1);
4422                 if (IS_ERR(trans))
4423                         return PTR_ERR(trans);
4424
4425                 i_size_write(inode, newsize);
4426                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
4427                 ret = btrfs_update_inode(trans, root, inode);
4428                 btrfs_end_transaction(trans, root);
4429         } else {
4430
4431                 /*
4432                  * We're truncating a file that used to have good data down to
4433                  * zero. Make sure it gets into the ordered flush list so that
4434                  * any new writes get down to disk quickly.
4435                  */
4436                 if (newsize == 0)
4437                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
4438                                 &BTRFS_I(inode)->runtime_flags);
4439
4440                 /*
4441                  * 1 for the orphan item we're going to add
4442                  * 1 for the orphan item deletion.
4443                  */
4444                 trans = btrfs_start_transaction(root, 2);
4445                 if (IS_ERR(trans))
4446                         return PTR_ERR(trans);
4447
4448                 /*
4449                  * We need to do this in case we fail at _any_ point during the
4450                  * actual truncate.  Once we do the truncate_setsize we could
4451                  * invalidate pages which forces any outstanding ordered io to
4452                  * be instantly completed which will give us extents that need
4453                  * to be truncated.  If we fail to get an orphan inode down we
4454                  * could have left over extents that were never meant to live,
4455                  * so we need to garuntee from this point on that everything
4456                  * will be consistent.
4457                  */
4458                 ret = btrfs_orphan_add(trans, inode);
4459                 btrfs_end_transaction(trans, root);
4460                 if (ret)
4461                         return ret;
4462
4463                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
4464                 truncate_setsize(inode, newsize);
4465
4466                 /* Disable nonlocked read DIO to avoid the end less truncate */
4467                 btrfs_inode_block_unlocked_dio(inode);
4468                 inode_dio_wait(inode);
4469                 btrfs_inode_resume_unlocked_dio(inode);
4470
4471                 ret = btrfs_truncate(inode);
4472                 if (ret && inode->i_nlink) {
4473                         int err;
4474
4475                         /*
4476                          * failed to truncate, disk_i_size is only adjusted down
4477                          * as we remove extents, so it should represent the true
4478                          * size of the inode, so reset the in memory size and
4479                          * delete our orphan entry.
4480                          */
4481                         trans = btrfs_join_transaction(root);
4482                         if (IS_ERR(trans)) {
4483                                 btrfs_orphan_del(NULL, inode);
4484                                 return ret;
4485                         }
4486                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
4487                         err = btrfs_orphan_del(trans, inode);
4488                         if (err)
4489                                 btrfs_abort_transaction(trans, root, err);
4490                         btrfs_end_transaction(trans, root);
4491                 }
4492         }
4493
4494         return ret;
4495 }
4496
4497 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
4498 {
4499         struct inode *inode = dentry->d_inode;
4500         struct btrfs_root *root = BTRFS_I(inode)->root;
4501         int err;
4502
4503         if (btrfs_root_readonly(root))
4504                 return -EROFS;
4505
4506         err = inode_change_ok(inode, attr);
4507         if (err)
4508                 return err;
4509
4510         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
4511                 err = btrfs_setsize(inode, attr);
4512                 if (err)
4513                         return err;
4514         }
4515
4516         if (attr->ia_valid) {
4517                 setattr_copy(inode, attr);
4518                 inode_inc_iversion(inode);
4519                 err = btrfs_dirty_inode(inode);
4520
4521                 if (!err && attr->ia_valid & ATTR_MODE)
4522                         err = btrfs_acl_chmod(inode);
4523         }
4524
4525         return err;
4526 }
4527
4528 /*
4529  * While truncating the inode pages during eviction, we get the VFS calling
4530  * btrfs_invalidatepage() against each page of the inode. This is slow because
4531  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
4532  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
4533  * extent_state structures over and over, wasting lots of time.
4534  *
4535  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
4536  * those expensive operations on a per page basis and do only the ordered io
4537  * finishing, while we release here the extent_map and extent_state structures,
4538  * without the excessive merging and splitting.
4539  */
4540 static void evict_inode_truncate_pages(struct inode *inode)
4541 {
4542         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4543         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
4544         struct rb_node *node;
4545
4546         ASSERT(inode->i_state & I_FREEING);
4547         truncate_inode_pages(&inode->i_data, 0);
4548
4549         write_lock(&map_tree->lock);
4550         while (!RB_EMPTY_ROOT(&map_tree->map)) {
4551                 struct extent_map *em;
4552
4553                 node = rb_first(&map_tree->map);
4554                 em = rb_entry(node, struct extent_map, rb_node);
4555                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
4556                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
4557                 remove_extent_mapping(map_tree, em);
4558                 free_extent_map(em);
4559         }
4560         write_unlock(&map_tree->lock);
4561
4562         spin_lock(&io_tree->lock);
4563         while (!RB_EMPTY_ROOT(&io_tree->state)) {
4564                 struct extent_state *state;
4565                 struct extent_state *cached_state = NULL;
4566
4567                 node = rb_first(&io_tree->state);
4568                 state = rb_entry(node, struct extent_state, rb_node);
4569                 atomic_inc(&state->refs);
4570                 spin_unlock(&io_tree->lock);
4571
4572                 lock_extent_bits(io_tree, state->start, state->end,
4573                                  0, &cached_state);
4574                 clear_extent_bit(io_tree, state->start, state->end,
4575                                  EXTENT_LOCKED | EXTENT_DIRTY |
4576                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
4577                                  EXTENT_DEFRAG, 1, 1,
4578                                  &cached_state, GFP_NOFS);
4579                 free_extent_state(state);
4580
4581                 spin_lock(&io_tree->lock);
4582         }
4583         spin_unlock(&io_tree->lock);
4584 }
4585
4586 void btrfs_evict_inode(struct inode *inode)
4587 {
4588         struct btrfs_trans_handle *trans;
4589         struct btrfs_root *root = BTRFS_I(inode)->root;
4590         struct btrfs_block_rsv *rsv, *global_rsv;
4591         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
4592         int ret;
4593
4594         trace_btrfs_inode_evict(inode);
4595
4596         evict_inode_truncate_pages(inode);
4597
4598         if (inode->i_nlink &&
4599             ((btrfs_root_refs(&root->root_item) != 0 &&
4600               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
4601              btrfs_is_free_space_inode(inode)))
4602                 goto no_delete;
4603
4604         if (is_bad_inode(inode)) {
4605                 btrfs_orphan_del(NULL, inode);
4606                 goto no_delete;
4607         }
4608         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
4609         btrfs_wait_ordered_range(inode, 0, (u64)-1);
4610
4611         if (root->fs_info->log_root_recovering) {
4612                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
4613                                  &BTRFS_I(inode)->runtime_flags));
4614                 goto no_delete;
4615         }
4616
4617         if (inode->i_nlink > 0) {
4618                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
4619                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
4620                 goto no_delete;
4621         }
4622
4623         ret = btrfs_commit_inode_delayed_inode(inode);
4624         if (ret) {
4625                 btrfs_orphan_del(NULL, inode);
4626                 goto no_delete;
4627         }
4628
4629         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
4630         if (!rsv) {
4631                 btrfs_orphan_del(NULL, inode);
4632                 goto no_delete;
4633         }
4634         rsv->size = min_size;
4635         rsv->failfast = 1;
4636         global_rsv = &root->fs_info->global_block_rsv;
4637
4638         btrfs_i_size_write(inode, 0);
4639
4640         /*
4641          * This is a bit simpler than btrfs_truncate since we've already
4642          * reserved our space for our orphan item in the unlink, so we just
4643          * need to reserve some slack space in case we add bytes and update
4644          * inode item when doing the truncate.
4645          */
4646         while (1) {
4647                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
4648                                              BTRFS_RESERVE_FLUSH_LIMIT);
4649
4650                 /*
4651                  * Try and steal from the global reserve since we will
4652                  * likely not use this space anyway, we want to try as
4653                  * hard as possible to get this to work.
4654                  */
4655                 if (ret)
4656                         ret = btrfs_block_rsv_migrate(global_rsv, rsv, min_size);
4657
4658                 if (ret) {
4659                         btrfs_warn(root->fs_info,
4660                                 "Could not get space for a delete, will truncate on mount %d",
4661                                 ret);
4662                         btrfs_orphan_del(NULL, inode);
4663                         btrfs_free_block_rsv(root, rsv);
4664                         goto no_delete;
4665                 }
4666
4667                 trans = btrfs_join_transaction(root);
4668                 if (IS_ERR(trans)) {
4669                         btrfs_orphan_del(NULL, inode);
4670                         btrfs_free_block_rsv(root, rsv);
4671                         goto no_delete;
4672                 }
4673
4674                 trans->block_rsv = rsv;
4675
4676                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
4677                 if (ret != -ENOSPC)
4678                         break;
4679
4680                 trans->block_rsv = &root->fs_info->trans_block_rsv;
4681                 btrfs_end_transaction(trans, root);
4682                 trans = NULL;
4683                 btrfs_btree_balance_dirty(root);
4684         }
4685
4686         btrfs_free_block_rsv(root, rsv);
4687
4688         /*
4689          * Errors here aren't a big deal, it just means we leave orphan items
4690          * in the tree.  They will be cleaned up on the next mount.
4691          */
4692         if (ret == 0) {
4693                 trans->block_rsv = root->orphan_block_rsv;
4694                 btrfs_orphan_del(trans, inode);
4695         } else {
4696                 btrfs_orphan_del(NULL, inode);
4697         }
4698
4699         trans->block_rsv = &root->fs_info->trans_block_rsv;
4700         if (!(root == root->fs_info->tree_root ||
4701               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
4702                 btrfs_return_ino(root, btrfs_ino(inode));
4703
4704         btrfs_end_transaction(trans, root);
4705         btrfs_btree_balance_dirty(root);
4706 no_delete:
4707         btrfs_remove_delayed_node(inode);
4708         clear_inode(inode);
4709         return;
4710 }
4711
4712 /*
4713  * this returns the key found in the dir entry in the location pointer.
4714  * If no dir entries were found, location->objectid is 0.
4715  */
4716 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
4717                                struct btrfs_key *location)
4718 {
4719         const char *name = dentry->d_name.name;
4720         int namelen = dentry->d_name.len;
4721         struct btrfs_dir_item *di;
4722         struct btrfs_path *path;
4723         struct btrfs_root *root = BTRFS_I(dir)->root;
4724         int ret = 0;
4725
4726         path = btrfs_alloc_path();
4727         if (!path)
4728                 return -ENOMEM;
4729
4730         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
4731                                     namelen, 0);
4732         if (IS_ERR(di))
4733                 ret = PTR_ERR(di);
4734
4735         if (IS_ERR_OR_NULL(di))
4736                 goto out_err;
4737
4738         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
4739 out:
4740         btrfs_free_path(path);
4741         return ret;
4742 out_err:
4743         location->objectid = 0;
4744         goto out;
4745 }
4746
4747 /*
4748  * when we hit a tree root in a directory, the btrfs part of the inode
4749  * needs to be changed to reflect the root directory of the tree root.  This
4750  * is kind of like crossing a mount point.
4751  */
4752 static int fixup_tree_root_location(struct btrfs_root *root,
4753                                     struct inode *dir,
4754                                     struct dentry *dentry,
4755                                     struct btrfs_key *location,
4756                                     struct btrfs_root **sub_root)
4757 {
4758         struct btrfs_path *path;
4759         struct btrfs_root *new_root;
4760         struct btrfs_root_ref *ref;
4761         struct extent_buffer *leaf;
4762         int ret;
4763         int err = 0;
4764
4765         path = btrfs_alloc_path();
4766         if (!path) {
4767                 err = -ENOMEM;
4768                 goto out;
4769         }
4770
4771         err = -ENOENT;
4772         ret = btrfs_find_item(root->fs_info->tree_root, path,
4773                                 BTRFS_I(dir)->root->root_key.objectid,
4774                                 location->objectid, BTRFS_ROOT_REF_KEY, NULL);
4775         if (ret) {
4776                 if (ret < 0)
4777                         err = ret;
4778                 goto out;
4779         }
4780
4781         leaf = path->nodes[0];
4782         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
4783         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
4784             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
4785                 goto out;
4786
4787         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
4788                                    (unsigned long)(ref + 1),
4789                                    dentry->d_name.len);
4790         if (ret)
4791                 goto out;
4792
4793         btrfs_release_path(path);
4794
4795         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
4796         if (IS_ERR(new_root)) {
4797                 err = PTR_ERR(new_root);
4798                 goto out;
4799         }
4800
4801         *sub_root = new_root;
4802         location->objectid = btrfs_root_dirid(&new_root->root_item);
4803         location->type = BTRFS_INODE_ITEM_KEY;
4804         location->offset = 0;
4805         err = 0;
4806 out:
4807         btrfs_free_path(path);
4808         return err;
4809 }
4810
4811 static void inode_tree_add(struct inode *inode)
4812 {
4813         struct btrfs_root *root = BTRFS_I(inode)->root;
4814         struct btrfs_inode *entry;
4815         struct rb_node **p;
4816         struct rb_node *parent;
4817         struct rb_node *new = &BTRFS_I(inode)->rb_node;
4818         u64 ino = btrfs_ino(inode);
4819
4820         if (inode_unhashed(inode))
4821                 return;
4822         parent = NULL;
4823         spin_lock(&root->inode_lock);
4824         p = &root->inode_tree.rb_node;
4825         while (*p) {
4826                 parent = *p;
4827                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
4828
4829                 if (ino < btrfs_ino(&entry->vfs_inode))
4830                         p = &parent->rb_left;
4831                 else if (ino > btrfs_ino(&entry->vfs_inode))
4832                         p = &parent->rb_right;
4833                 else {
4834                         WARN_ON(!(entry->vfs_inode.i_state &
4835                                   (I_WILL_FREE | I_FREEING)));
4836                         rb_replace_node(parent, new, &root->inode_tree);
4837                         RB_CLEAR_NODE(parent);
4838                         spin_unlock(&root->inode_lock);
4839                         return;
4840                 }
4841         }
4842         rb_link_node(new, parent, p);
4843         rb_insert_color(new, &root->inode_tree);
4844         spin_unlock(&root->inode_lock);
4845 }
4846
4847 static void inode_tree_del(struct inode *inode)
4848 {
4849         struct btrfs_root *root = BTRFS_I(inode)->root;
4850         int empty = 0;
4851
4852         spin_lock(&root->inode_lock);
4853         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
4854                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
4855                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
4856                 empty = RB_EMPTY_ROOT(&root->inode_tree);
4857         }
4858         spin_unlock(&root->inode_lock);
4859
4860         if (empty && btrfs_root_refs(&root->root_item) == 0) {
4861                 synchronize_srcu(&root->fs_info->subvol_srcu);
4862                 spin_lock(&root->inode_lock);
4863                 empty = RB_EMPTY_ROOT(&root->inode_tree);
4864                 spin_unlock(&root->inode_lock);
4865                 if (empty)
4866                         btrfs_add_dead_root(root);
4867         }
4868 }
4869
4870 void btrfs_invalidate_inodes(struct btrfs_root *root)
4871 {
4872         struct rb_node *node;
4873         struct rb_node *prev;
4874         struct btrfs_inode *entry;
4875         struct inode *inode;
4876         u64 objectid = 0;
4877
4878         WARN_ON(btrfs_root_refs(&root->root_item) != 0);
4879
4880         spin_lock(&root->inode_lock);
4881 again:
4882         node = root->inode_tree.rb_node;
4883         prev = NULL;
4884         while (node) {
4885                 prev = node;
4886                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4887
4888                 if (objectid < btrfs_ino(&entry->vfs_inode))
4889                         node = node->rb_left;
4890                 else if (objectid > btrfs_ino(&entry->vfs_inode))
4891                         node = node->rb_right;
4892                 else
4893                         break;
4894         }
4895         if (!node) {
4896                 while (prev) {
4897                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
4898                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
4899                                 node = prev;
4900                                 break;
4901                         }
4902                         prev = rb_next(prev);
4903                 }
4904         }
4905         while (node) {
4906                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4907                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
4908                 inode = igrab(&entry->vfs_inode);
4909                 if (inode) {
4910                         spin_unlock(&root->inode_lock);
4911                         if (atomic_read(&inode->i_count) > 1)
4912                                 d_prune_aliases(inode);
4913                         /*
4914                          * btrfs_drop_inode will have it removed from
4915                          * the inode cache when its usage count
4916                          * hits zero.
4917                          */
4918                         iput(inode);
4919                         cond_resched();
4920                         spin_lock(&root->inode_lock);
4921                         goto again;
4922                 }
4923
4924                 if (cond_resched_lock(&root->inode_lock))
4925                         goto again;
4926
4927                 node = rb_next(node);
4928         }
4929         spin_unlock(&root->inode_lock);
4930 }
4931
4932 static int btrfs_init_locked_inode(struct inode *inode, void *p)
4933 {
4934         struct btrfs_iget_args *args = p;
4935         inode->i_ino = args->ino;
4936         BTRFS_I(inode)->root = args->root;
4937         return 0;
4938 }
4939
4940 static int btrfs_find_actor(struct inode *inode, void *opaque)
4941 {
4942         struct btrfs_iget_args *args = opaque;
4943         return args->ino == btrfs_ino(inode) &&
4944                 args->root == BTRFS_I(inode)->root;
4945 }
4946
4947 static struct inode *btrfs_iget_locked(struct super_block *s,
4948                                        u64 objectid,
4949                                        struct btrfs_root *root)
4950 {
4951         struct inode *inode;
4952         struct btrfs_iget_args args;
4953         unsigned long hashval = btrfs_inode_hash(objectid, root);
4954
4955         args.ino = objectid;
4956         args.root = root;
4957
4958         inode = iget5_locked(s, hashval, btrfs_find_actor,
4959                              btrfs_init_locked_inode,
4960                              (void *)&args);
4961         return inode;
4962 }
4963
4964 /* Get an inode object given its location and corresponding root.
4965  * Returns in *is_new if the inode was read from disk
4966  */
4967 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
4968                          struct btrfs_root *root, int *new)
4969 {
4970         struct inode *inode;
4971
4972         inode = btrfs_iget_locked(s, location->objectid, root);
4973         if (!inode)
4974                 return ERR_PTR(-ENOMEM);
4975
4976         if (inode->i_state & I_NEW) {
4977                 BTRFS_I(inode)->root = root;
4978                 memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
4979                 btrfs_read_locked_inode(inode);
4980                 if (!is_bad_inode(inode)) {
4981                         inode_tree_add(inode);
4982                         unlock_new_inode(inode);
4983                         if (new)
4984                                 *new = 1;
4985                 } else {
4986                         unlock_new_inode(inode);
4987                         iput(inode);
4988                         inode = ERR_PTR(-ESTALE);
4989                 }
4990         }
4991
4992         return inode;
4993 }
4994
4995 static struct inode *new_simple_dir(struct super_block *s,
4996                                     struct btrfs_key *key,
4997                                     struct btrfs_root *root)
4998 {
4999         struct inode *inode = new_inode(s);
5000
5001         if (!inode)
5002                 return ERR_PTR(-ENOMEM);
5003
5004         BTRFS_I(inode)->root = root;
5005         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5006         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5007
5008         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5009         inode->i_op = &btrfs_dir_ro_inode_operations;
5010         inode->i_fop = &simple_dir_operations;
5011         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5012         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5013
5014         return inode;
5015 }
5016
5017 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5018 {
5019         struct inode *inode;
5020         struct btrfs_root *root = BTRFS_I(dir)->root;
5021         struct btrfs_root *sub_root = root;
5022         struct btrfs_key location;
5023         int index;
5024         int ret = 0;
5025
5026         if (dentry->d_name.len > BTRFS_NAME_LEN)
5027                 return ERR_PTR(-ENAMETOOLONG);
5028
5029         ret = btrfs_inode_by_name(dir, dentry, &location);
5030         if (ret < 0)
5031                 return ERR_PTR(ret);
5032
5033         if (location.objectid == 0)
5034                 return ERR_PTR(-ENOENT);
5035
5036         if (location.type == BTRFS_INODE_ITEM_KEY) {
5037                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5038                 return inode;
5039         }
5040
5041         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
5042
5043         index = srcu_read_lock(&root->fs_info->subvol_srcu);
5044         ret = fixup_tree_root_location(root, dir, dentry,
5045                                        &location, &sub_root);
5046         if (ret < 0) {
5047                 if (ret != -ENOENT)
5048                         inode = ERR_PTR(ret);
5049                 else
5050                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5051         } else {
5052                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5053         }
5054         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
5055
5056         if (!IS_ERR(inode) && root != sub_root) {
5057                 down_read(&root->fs_info->cleanup_work_sem);
5058                 if (!(inode->i_sb->s_flags & MS_RDONLY))
5059                         ret = btrfs_orphan_cleanup(sub_root);
5060                 up_read(&root->fs_info->cleanup_work_sem);
5061                 if (ret) {
5062                         iput(inode);
5063                         inode = ERR_PTR(ret);
5064                 }
5065         }
5066
5067         return inode;
5068 }
5069
5070 static int btrfs_dentry_delete(const struct dentry *dentry)
5071 {
5072         struct btrfs_root *root;
5073         struct inode *inode = dentry->d_inode;
5074
5075         if (!inode && !IS_ROOT(dentry))
5076                 inode = dentry->d_parent->d_inode;
5077
5078         if (inode) {
5079                 root = BTRFS_I(inode)->root;
5080                 if (btrfs_root_refs(&root->root_item) == 0)
5081                         return 1;
5082
5083                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5084                         return 1;
5085         }
5086         return 0;
5087 }
5088
5089 static void btrfs_dentry_release(struct dentry *dentry)
5090 {
5091         if (dentry->d_fsdata)
5092                 kfree(dentry->d_fsdata);
5093 }
5094
5095 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5096                                    unsigned int flags)
5097 {
5098         struct inode *inode;
5099
5100         inode = btrfs_lookup_dentry(dir, dentry);
5101         if (IS_ERR(inode)) {
5102                 if (PTR_ERR(inode) == -ENOENT)
5103                         inode = NULL;
5104                 else
5105                         return ERR_CAST(inode);
5106         }
5107
5108         return d_splice_alias(inode, dentry);
5109 }
5110
5111 unsigned char btrfs_filetype_table[] = {
5112         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5113 };
5114
5115 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5116 {
5117         struct inode *inode = file_inode(file);
5118         struct btrfs_root *root = BTRFS_I(inode)->root;
5119         struct btrfs_item *item;
5120         struct btrfs_dir_item *di;
5121         struct btrfs_key key;
5122         struct btrfs_key found_key;
5123         struct btrfs_path *path;
5124         struct list_head ins_list;
5125         struct list_head del_list;
5126         int ret;
5127         struct extent_buffer *leaf;
5128         int slot;
5129         unsigned char d_type;
5130         int over = 0;
5131         u32 di_cur;
5132         u32 di_total;
5133         u32 di_len;
5134         int key_type = BTRFS_DIR_INDEX_KEY;
5135         char tmp_name[32];
5136         char *name_ptr;
5137         int name_len;
5138         int is_curr = 0;        /* ctx->pos points to the current index? */
5139
5140         /* FIXME, use a real flag for deciding about the key type */
5141         if (root->fs_info->tree_root == root)
5142                 key_type = BTRFS_DIR_ITEM_KEY;
5143
5144         if (!dir_emit_dots(file, ctx))
5145                 return 0;
5146
5147         path = btrfs_alloc_path();
5148         if (!path)
5149                 return -ENOMEM;
5150
5151         path->reada = 1;
5152
5153         if (key_type == BTRFS_DIR_INDEX_KEY) {
5154                 INIT_LIST_HEAD(&ins_list);
5155                 INIT_LIST_HEAD(&del_list);
5156                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
5157         }
5158
5159         btrfs_set_key_type(&key, key_type);
5160         key.offset = ctx->pos;
5161         key.objectid = btrfs_ino(inode);
5162
5163         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5164         if (ret < 0)
5165                 goto err;
5166
5167         while (1) {
5168                 leaf = path->nodes[0];
5169                 slot = path->slots[0];
5170                 if (slot >= btrfs_header_nritems(leaf)) {
5171                         ret = btrfs_next_leaf(root, path);
5172                         if (ret < 0)
5173                                 goto err;
5174                         else if (ret > 0)
5175                                 break;
5176                         continue;
5177                 }
5178
5179                 item = btrfs_item_nr(slot);
5180                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5181
5182                 if (found_key.objectid != key.objectid)
5183                         break;
5184                 if (btrfs_key_type(&found_key) != key_type)
5185                         break;
5186                 if (found_key.offset < ctx->pos)
5187                         goto next;
5188                 if (key_type == BTRFS_DIR_INDEX_KEY &&
5189                     btrfs_should_delete_dir_index(&del_list,
5190                                                   found_key.offset))
5191                         goto next;
5192
5193                 ctx->pos = found_key.offset;
5194                 is_curr = 1;
5195
5196                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5197                 di_cur = 0;
5198                 di_total = btrfs_item_size(leaf, item);
5199
5200                 while (di_cur < di_total) {
5201                         struct btrfs_key location;
5202
5203                         if (verify_dir_item(root, leaf, di))
5204                                 break;
5205
5206                         name_len = btrfs_dir_name_len(leaf, di);
5207                         if (name_len <= sizeof(tmp_name)) {
5208                                 name_ptr = tmp_name;
5209                         } else {
5210                                 name_ptr = kmalloc(name_len, GFP_NOFS);
5211                                 if (!name_ptr) {
5212                                         ret = -ENOMEM;
5213                                         goto err;
5214                                 }
5215                         }
5216                         read_extent_buffer(leaf, name_ptr,
5217                                            (unsigned long)(di + 1), name_len);
5218
5219                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
5220                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
5221
5222
5223                         /* is this a reference to our own snapshot? If so
5224                          * skip it.
5225                          *
5226                          * In contrast to old kernels, we insert the snapshot's
5227                          * dir item and dir index after it has been created, so
5228                          * we won't find a reference to our own snapshot. We
5229                          * still keep the following code for backward
5230                          * compatibility.
5231                          */
5232                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
5233                             location.objectid == root->root_key.objectid) {
5234                                 over = 0;
5235                                 goto skip;
5236                         }
5237                         over = !dir_emit(ctx, name_ptr, name_len,
5238                                        location.objectid, d_type);
5239
5240 skip:
5241                         if (name_ptr != tmp_name)
5242                                 kfree(name_ptr);
5243
5244                         if (over)
5245                                 goto nopos;
5246                         di_len = btrfs_dir_name_len(leaf, di) +
5247                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
5248                         di_cur += di_len;
5249                         di = (struct btrfs_dir_item *)((char *)di + di_len);
5250                 }
5251 next:
5252                 path->slots[0]++;
5253         }
5254
5255         if (key_type == BTRFS_DIR_INDEX_KEY) {
5256                 if (is_curr)
5257                         ctx->pos++;
5258                 ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5259                 if (ret)
5260                         goto nopos;
5261         }
5262
5263         /* Reached end of directory/root. Bump pos past the last item. */
5264         ctx->pos++;
5265
5266         /*
5267          * Stop new entries from being returned after we return the last
5268          * entry.
5269          *
5270          * New directory entries are assigned a strictly increasing
5271          * offset.  This means that new entries created during readdir
5272          * are *guaranteed* to be seen in the future by that readdir.
5273          * This has broken buggy programs which operate on names as
5274          * they're returned by readdir.  Until we re-use freed offsets
5275          * we have this hack to stop new entries from being returned
5276          * under the assumption that they'll never reach this huge
5277          * offset.
5278          *
5279          * This is being careful not to overflow 32bit loff_t unless the
5280          * last entry requires it because doing so has broken 32bit apps
5281          * in the past.
5282          */
5283         if (key_type == BTRFS_DIR_INDEX_KEY) {
5284                 if (ctx->pos >= INT_MAX)
5285                         ctx->pos = LLONG_MAX;
5286                 else
5287                         ctx->pos = INT_MAX;
5288         }
5289 nopos:
5290         ret = 0;
5291 err:
5292         if (key_type == BTRFS_DIR_INDEX_KEY)
5293                 btrfs_put_delayed_items(&ins_list, &del_list);
5294         btrfs_free_path(path);
5295         return ret;
5296 }
5297
5298 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
5299 {
5300         struct btrfs_root *root = BTRFS_I(inode)->root;
5301         struct btrfs_trans_handle *trans;
5302         int ret = 0;
5303         bool nolock = false;
5304
5305         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5306                 return 0;
5307
5308         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
5309                 nolock = true;
5310
5311         if (wbc->sync_mode == WB_SYNC_ALL) {
5312                 if (nolock)
5313                         trans = btrfs_join_transaction_nolock(root);
5314                 else
5315                         trans = btrfs_join_transaction(root);
5316                 if (IS_ERR(trans))
5317                         return PTR_ERR(trans);
5318                 ret = btrfs_commit_transaction(trans, root);
5319         }
5320         return ret;
5321 }
5322
5323 /*
5324  * This is somewhat expensive, updating the tree every time the
5325  * inode changes.  But, it is most likely to find the inode in cache.
5326  * FIXME, needs more benchmarking...there are no reasons other than performance
5327  * to keep or drop this code.
5328  */
5329 static int btrfs_dirty_inode(struct inode *inode)
5330 {
5331         struct btrfs_root *root = BTRFS_I(inode)->root;
5332         struct btrfs_trans_handle *trans;
5333         int ret;
5334
5335         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5336                 return 0;
5337
5338         trans = btrfs_join_transaction(root);
5339         if (IS_ERR(trans))
5340                 return PTR_ERR(trans);
5341
5342         ret = btrfs_update_inode(trans, root, inode);
5343         if (ret && ret == -ENOSPC) {
5344                 /* whoops, lets try again with the full transaction */
5345                 btrfs_end_transaction(trans, root);
5346                 trans = btrfs_start_transaction(root, 1);
5347                 if (IS_ERR(trans))
5348                         return PTR_ERR(trans);
5349
5350                 ret = btrfs_update_inode(trans, root, inode);
5351         }
5352         btrfs_end_transaction(trans, root);
5353         if (BTRFS_I(inode)->delayed_node)
5354                 btrfs_balance_delayed_items(root);
5355
5356         return ret;
5357 }
5358
5359 /*
5360  * This is a copy of file_update_time.  We need this so we can return error on
5361  * ENOSPC for updating the inode in the case of file write and mmap writes.
5362  */
5363 static int btrfs_update_time(struct inode *inode, struct timespec *now,
5364                              int flags)
5365 {
5366         struct btrfs_root *root = BTRFS_I(inode)->root;
5367
5368         if (btrfs_root_readonly(root))
5369                 return -EROFS;
5370
5371         if (flags & S_VERSION)
5372                 inode_inc_iversion(inode);
5373         if (flags & S_CTIME)
5374                 inode->i_ctime = *now;
5375         if (flags & S_MTIME)
5376                 inode->i_mtime = *now;
5377         if (flags & S_ATIME)
5378                 inode->i_atime = *now;
5379         return btrfs_dirty_inode(inode);
5380 }
5381
5382 /*
5383  * find the highest existing sequence number in a directory
5384  * and then set the in-memory index_cnt variable to reflect
5385  * free sequence numbers
5386  */
5387 static int btrfs_set_inode_index_count(struct inode *inode)
5388 {
5389         struct btrfs_root *root = BTRFS_I(inode)->root;
5390         struct btrfs_key key, found_key;
5391         struct btrfs_path *path;
5392         struct extent_buffer *leaf;
5393         int ret;
5394
5395         key.objectid = btrfs_ino(inode);
5396         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
5397         key.offset = (u64)-1;
5398
5399         path = btrfs_alloc_path();
5400         if (!path)
5401                 return -ENOMEM;
5402
5403         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5404         if (ret < 0)
5405                 goto out;
5406         /* FIXME: we should be able to handle this */
5407         if (ret == 0)
5408                 goto out;
5409         ret = 0;
5410
5411         /*
5412          * MAGIC NUMBER EXPLANATION:
5413          * since we search a directory based on f_pos we have to start at 2
5414          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
5415          * else has to start at 2
5416          */
5417         if (path->slots[0] == 0) {
5418                 BTRFS_I(inode)->index_cnt = 2;
5419                 goto out;
5420         }
5421
5422         path->slots[0]--;
5423
5424         leaf = path->nodes[0];
5425         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5426
5427         if (found_key.objectid != btrfs_ino(inode) ||
5428             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
5429                 BTRFS_I(inode)->index_cnt = 2;
5430                 goto out;
5431         }
5432
5433         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
5434 out:
5435         btrfs_free_path(path);
5436         return ret;
5437 }
5438
5439 /*
5440  * helper to find a free sequence number in a given directory.  This current
5441  * code is very simple, later versions will do smarter things in the btree
5442  */
5443 int btrfs_set_inode_index(struct inode *dir, u64 *index)
5444 {
5445         int ret = 0;
5446
5447         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
5448                 ret = btrfs_inode_delayed_dir_index_count(dir);
5449                 if (ret) {
5450                         ret = btrfs_set_inode_index_count(dir);
5451                         if (ret)
5452                                 return ret;
5453                 }
5454         }
5455
5456         *index = BTRFS_I(dir)->index_cnt;
5457         BTRFS_I(dir)->index_cnt++;
5458
5459         return ret;
5460 }
5461
5462 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
5463                                      struct btrfs_root *root,
5464                                      struct inode *dir,
5465                                      const char *name, int name_len,
5466                                      u64 ref_objectid, u64 objectid,
5467                                      umode_t mode, u64 *index)
5468 {
5469         struct inode *inode;
5470         struct btrfs_inode_item *inode_item;
5471         struct btrfs_key *location;
5472         struct btrfs_path *path;
5473         struct btrfs_inode_ref *ref;
5474         struct btrfs_key key[2];
5475         u32 sizes[2];
5476         unsigned long ptr;
5477         int ret;
5478
5479         path = btrfs_alloc_path();
5480         if (!path)
5481                 return ERR_PTR(-ENOMEM);
5482
5483         inode = new_inode(root->fs_info->sb);
5484         if (!inode) {
5485                 btrfs_free_path(path);
5486                 return ERR_PTR(-ENOMEM);
5487         }
5488
5489         /*
5490          * we have to initialize this early, so we can reclaim the inode
5491          * number if we fail afterwards in this function.
5492          */
5493         inode->i_ino = objectid;
5494
5495         if (dir) {
5496                 trace_btrfs_inode_request(dir);
5497
5498                 ret = btrfs_set_inode_index(dir, index);
5499                 if (ret) {
5500                         btrfs_free_path(path);
5501                         iput(inode);
5502                         return ERR_PTR(ret);
5503                 }
5504         }
5505         /*
5506          * index_cnt is ignored for everything but a dir,
5507          * btrfs_get_inode_index_count has an explanation for the magic
5508          * number
5509          */
5510         BTRFS_I(inode)->index_cnt = 2;
5511         BTRFS_I(inode)->dir_index = *index;
5512         BTRFS_I(inode)->root = root;
5513         BTRFS_I(inode)->generation = trans->transid;
5514         inode->i_generation = BTRFS_I(inode)->generation;
5515
5516         /*
5517          * We could have gotten an inode number from somebody who was fsynced
5518          * and then removed in this same transaction, so let's just set full
5519          * sync since it will be a full sync anyway and this will blow away the
5520          * old info in the log.
5521          */
5522         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
5523
5524         key[0].objectid = objectid;
5525         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
5526         key[0].offset = 0;
5527
5528         /*
5529          * Start new inodes with an inode_ref. This is slightly more
5530          * efficient for small numbers of hard links since they will
5531          * be packed into one item. Extended refs will kick in if we
5532          * add more hard links than can fit in the ref item.
5533          */
5534         key[1].objectid = objectid;
5535         btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
5536         key[1].offset = ref_objectid;
5537
5538         sizes[0] = sizeof(struct btrfs_inode_item);
5539         sizes[1] = name_len + sizeof(*ref);
5540
5541         path->leave_spinning = 1;
5542         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
5543         if (ret != 0)
5544                 goto fail;
5545
5546         inode_init_owner(inode, dir, mode);
5547         inode_set_bytes(inode, 0);
5548         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5549         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
5550                                   struct btrfs_inode_item);
5551         memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
5552                              sizeof(*inode_item));
5553         fill_inode_item(trans, path->nodes[0], inode_item, inode);
5554
5555         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
5556                              struct btrfs_inode_ref);
5557         btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
5558         btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
5559         ptr = (unsigned long)(ref + 1);
5560         write_extent_buffer(path->nodes[0], name, ptr, name_len);
5561
5562         btrfs_mark_buffer_dirty(path->nodes[0]);
5563         btrfs_free_path(path);
5564
5565         location = &BTRFS_I(inode)->location;
5566         location->objectid = objectid;
5567         location->offset = 0;
5568         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
5569
5570         btrfs_inherit_iflags(inode, dir);
5571
5572         if (S_ISREG(mode)) {
5573                 if (btrfs_test_opt(root, NODATASUM))
5574                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
5575                 if (btrfs_test_opt(root, NODATACOW))
5576                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
5577                                 BTRFS_INODE_NODATASUM;
5578         }
5579
5580         btrfs_insert_inode_hash(inode);
5581         inode_tree_add(inode);
5582
5583         trace_btrfs_inode_new(inode);
5584         btrfs_set_inode_last_trans(trans, inode);
5585
5586         btrfs_update_root_times(trans, root);
5587
5588         return inode;
5589 fail:
5590         if (dir)
5591                 BTRFS_I(dir)->index_cnt--;
5592         btrfs_free_path(path);
5593         iput(inode);
5594         return ERR_PTR(ret);
5595 }
5596
5597 static inline u8 btrfs_inode_type(struct inode *inode)
5598 {
5599         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
5600 }
5601
5602 /*
5603  * utility function to add 'inode' into 'parent_inode' with
5604  * a give name and a given sequence number.
5605  * if 'add_backref' is true, also insert a backref from the
5606  * inode to the parent directory.
5607  */
5608 int btrfs_add_link(struct btrfs_trans_handle *trans,
5609                    struct inode *parent_inode, struct inode *inode,
5610                    const char *name, int name_len, int add_backref, u64 index)
5611 {
5612         int ret = 0;
5613         struct btrfs_key key;
5614         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
5615         u64 ino = btrfs_ino(inode);
5616         u64 parent_ino = btrfs_ino(parent_inode);
5617
5618         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5619                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
5620         } else {
5621                 key.objectid = ino;
5622                 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
5623                 key.offset = 0;
5624         }
5625
5626         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5627                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
5628                                          key.objectid, root->root_key.objectid,
5629                                          parent_ino, index, name, name_len);
5630         } else if (add_backref) {
5631                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
5632                                              parent_ino, index);
5633         }
5634
5635         /* Nothing to clean up yet */
5636         if (ret)
5637                 return ret;
5638
5639         ret = btrfs_insert_dir_item(trans, root, name, name_len,
5640                                     parent_inode, &key,
5641                                     btrfs_inode_type(inode), index);
5642         if (ret == -EEXIST || ret == -EOVERFLOW)
5643                 goto fail_dir_item;
5644         else if (ret) {
5645                 btrfs_abort_transaction(trans, root, ret);
5646                 return ret;
5647         }
5648
5649         btrfs_i_size_write(parent_inode, parent_inode->i_size +
5650                            name_len * 2);
5651         inode_inc_iversion(parent_inode);
5652         parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
5653         ret = btrfs_update_inode(trans, root, parent_inode);
5654         if (ret)
5655                 btrfs_abort_transaction(trans, root, ret);
5656         return ret;
5657
5658 fail_dir_item:
5659         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5660                 u64 local_index;
5661                 int err;
5662                 err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
5663                                  key.objectid, root->root_key.objectid,
5664                                  parent_ino, &local_index, name, name_len);
5665
5666         } else if (add_backref) {
5667                 u64 local_index;
5668                 int err;
5669
5670                 err = btrfs_del_inode_ref(trans, root, name, name_len,
5671                                           ino, parent_ino, &local_index);
5672         }
5673         return ret;
5674 }
5675
5676 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
5677                             struct inode *dir, struct dentry *dentry,
5678                             struct inode *inode, int backref, u64 index)
5679 {
5680         int err = btrfs_add_link(trans, dir, inode,
5681                                  dentry->d_name.name, dentry->d_name.len,
5682                                  backref, index);
5683         if (err > 0)
5684                 err = -EEXIST;
5685         return err;
5686 }
5687
5688 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
5689                         umode_t mode, dev_t rdev)
5690 {
5691         struct btrfs_trans_handle *trans;
5692         struct btrfs_root *root = BTRFS_I(dir)->root;
5693         struct inode *inode = NULL;
5694         int err;
5695         int drop_inode = 0;
5696         u64 objectid;
5697         u64 index = 0;
5698
5699         if (!new_valid_dev(rdev))
5700                 return -EINVAL;
5701
5702         /*
5703          * 2 for inode item and ref
5704          * 2 for dir items
5705          * 1 for xattr if selinux is on
5706          */
5707         trans = btrfs_start_transaction(root, 5);
5708         if (IS_ERR(trans))
5709                 return PTR_ERR(trans);
5710
5711         err = btrfs_find_free_ino(root, &objectid);
5712         if (err)
5713                 goto out_unlock;
5714
5715         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5716                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5717                                 mode, &index);
5718         if (IS_ERR(inode)) {
5719                 err = PTR_ERR(inode);
5720                 goto out_unlock;
5721         }
5722
5723         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5724         if (err) {
5725                 drop_inode = 1;
5726                 goto out_unlock;
5727         }
5728
5729         /*
5730         * If the active LSM wants to access the inode during
5731         * d_instantiate it needs these. Smack checks to see
5732         * if the filesystem supports xattrs by looking at the
5733         * ops vector.
5734         */
5735
5736         inode->i_op = &btrfs_special_inode_operations;
5737         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
5738         if (err)
5739                 drop_inode = 1;
5740         else {
5741                 init_special_inode(inode, inode->i_mode, rdev);
5742                 btrfs_update_inode(trans, root, inode);
5743                 d_instantiate(dentry, inode);
5744         }
5745 out_unlock:
5746         btrfs_end_transaction(trans, root);
5747         btrfs_btree_balance_dirty(root);
5748         if (drop_inode) {
5749                 inode_dec_link_count(inode);
5750                 iput(inode);
5751         }
5752         return err;
5753 }
5754
5755 static int btrfs_create(struct inode *dir, struct dentry *dentry,
5756                         umode_t mode, bool excl)
5757 {
5758         struct btrfs_trans_handle *trans;
5759         struct btrfs_root *root = BTRFS_I(dir)->root;
5760         struct inode *inode = NULL;
5761         int drop_inode_on_err = 0;
5762         int err;
5763         u64 objectid;
5764         u64 index = 0;
5765
5766         /*
5767          * 2 for inode item and ref
5768          * 2 for dir items
5769          * 1 for xattr if selinux is on
5770          */
5771         trans = btrfs_start_transaction(root, 5);
5772         if (IS_ERR(trans))
5773                 return PTR_ERR(trans);
5774
5775         err = btrfs_find_free_ino(root, &objectid);
5776         if (err)
5777                 goto out_unlock;
5778
5779         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5780                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5781                                 mode, &index);
5782         if (IS_ERR(inode)) {
5783                 err = PTR_ERR(inode);
5784                 goto out_unlock;
5785         }
5786         drop_inode_on_err = 1;
5787
5788         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5789         if (err)
5790                 goto out_unlock;
5791
5792         err = btrfs_update_inode(trans, root, inode);
5793         if (err)
5794                 goto out_unlock;
5795
5796         /*
5797         * If the active LSM wants to access the inode during
5798         * d_instantiate it needs these. Smack checks to see
5799         * if the filesystem supports xattrs by looking at the
5800         * ops vector.
5801         */
5802         inode->i_fop = &btrfs_file_operations;
5803         inode->i_op = &btrfs_file_inode_operations;
5804
5805         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
5806         if (err)
5807                 goto out_unlock;
5808
5809         inode->i_mapping->a_ops = &btrfs_aops;
5810         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
5811         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
5812         d_instantiate(dentry, inode);
5813
5814 out_unlock:
5815         btrfs_end_transaction(trans, root);
5816         if (err && drop_inode_on_err) {
5817                 inode_dec_link_count(inode);
5818                 iput(inode);
5819         }
5820         btrfs_btree_balance_dirty(root);
5821         return err;
5822 }
5823
5824 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
5825                       struct dentry *dentry)
5826 {
5827         struct btrfs_trans_handle *trans;
5828         struct btrfs_root *root = BTRFS_I(dir)->root;
5829         struct inode *inode = old_dentry->d_inode;
5830         u64 index;
5831         int err;
5832         int drop_inode = 0;
5833
5834         /* do not allow sys_link's with other subvols of the same device */
5835         if (root->objectid != BTRFS_I(inode)->root->objectid)
5836                 return -EXDEV;
5837
5838         if (inode->i_nlink >= BTRFS_LINK_MAX)
5839                 return -EMLINK;
5840
5841         err = btrfs_set_inode_index(dir, &index);
5842         if (err)
5843                 goto fail;
5844
5845         /*
5846          * 2 items for inode and inode ref
5847          * 2 items for dir items
5848          * 1 item for parent inode
5849          */
5850         trans = btrfs_start_transaction(root, 5);
5851         if (IS_ERR(trans)) {
5852                 err = PTR_ERR(trans);
5853                 goto fail;
5854         }
5855
5856         /* There are several dir indexes for this inode, clear the cache. */
5857         BTRFS_I(inode)->dir_index = 0ULL;
5858         inc_nlink(inode);
5859         inode_inc_iversion(inode);
5860         inode->i_ctime = CURRENT_TIME;
5861         ihold(inode);
5862         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
5863
5864         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
5865
5866         if (err) {
5867                 drop_inode = 1;
5868         } else {
5869                 struct dentry *parent = dentry->d_parent;
5870                 err = btrfs_update_inode(trans, root, inode);
5871                 if (err)
5872                         goto fail;
5873                 d_instantiate(dentry, inode);
5874                 btrfs_log_new_name(trans, inode, NULL, parent);
5875         }
5876
5877         btrfs_end_transaction(trans, root);
5878 fail:
5879         if (drop_inode) {
5880                 inode_dec_link_count(inode);
5881                 iput(inode);
5882         }
5883         btrfs_btree_balance_dirty(root);
5884         return err;
5885 }
5886
5887 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
5888 {
5889         struct inode *inode = NULL;
5890         struct btrfs_trans_handle *trans;
5891         struct btrfs_root *root = BTRFS_I(dir)->root;
5892         int err = 0;
5893         int drop_on_err = 0;
5894         u64 objectid = 0;
5895         u64 index = 0;
5896
5897         /*
5898          * 2 items for inode and ref
5899          * 2 items for dir items
5900          * 1 for xattr if selinux is on
5901          */
5902         trans = btrfs_start_transaction(root, 5);
5903         if (IS_ERR(trans))
5904                 return PTR_ERR(trans);
5905
5906         err = btrfs_find_free_ino(root, &objectid);
5907         if (err)
5908                 goto out_fail;
5909
5910         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5911                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5912                                 S_IFDIR | mode, &index);
5913         if (IS_ERR(inode)) {
5914                 err = PTR_ERR(inode);
5915                 goto out_fail;
5916         }
5917
5918         drop_on_err = 1;
5919
5920         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5921         if (err)
5922                 goto out_fail;
5923
5924         inode->i_op = &btrfs_dir_inode_operations;
5925         inode->i_fop = &btrfs_dir_file_operations;
5926
5927         btrfs_i_size_write(inode, 0);
5928         err = btrfs_update_inode(trans, root, inode);
5929         if (err)
5930                 goto out_fail;
5931
5932         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
5933                              dentry->d_name.len, 0, index);
5934         if (err)
5935                 goto out_fail;
5936
5937         d_instantiate(dentry, inode);
5938         drop_on_err = 0;
5939
5940 out_fail:
5941         btrfs_end_transaction(trans, root);
5942         if (drop_on_err)
5943                 iput(inode);
5944         btrfs_btree_balance_dirty(root);
5945         return err;
5946 }
5947
5948 /* helper for btfs_get_extent.  Given an existing extent in the tree,
5949  * and an extent that you want to insert, deal with overlap and insert
5950  * the new extent into the tree.
5951  */
5952 static int merge_extent_mapping(struct extent_map_tree *em_tree,
5953                                 struct extent_map *existing,
5954                                 struct extent_map *em,
5955                                 u64 map_start, u64 map_len)
5956 {
5957         u64 start_diff;
5958
5959         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
5960         start_diff = map_start - em->start;
5961         em->start = map_start;
5962         em->len = map_len;
5963         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
5964             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
5965                 em->block_start += start_diff;
5966                 em->block_len -= start_diff;
5967         }
5968         return add_extent_mapping(em_tree, em, 0);
5969 }
5970
5971 static noinline int uncompress_inline(struct btrfs_path *path,
5972                                       struct inode *inode, struct page *page,
5973                                       size_t pg_offset, u64 extent_offset,
5974                                       struct btrfs_file_extent_item *item)
5975 {
5976         int ret;
5977         struct extent_buffer *leaf = path->nodes[0];
5978         char *tmp;
5979         size_t max_size;
5980         unsigned long inline_size;
5981         unsigned long ptr;
5982         int compress_type;
5983
5984         WARN_ON(pg_offset != 0);
5985         compress_type = btrfs_file_extent_compression(leaf, item);
5986         max_size = btrfs_file_extent_ram_bytes(leaf, item);
5987         inline_size = btrfs_file_extent_inline_item_len(leaf,
5988                                         btrfs_item_nr(path->slots[0]));
5989         tmp = kmalloc(inline_size, GFP_NOFS);
5990         if (!tmp)
5991                 return -ENOMEM;
5992         ptr = btrfs_file_extent_inline_start(item);
5993
5994         read_extent_buffer(leaf, tmp, ptr, inline_size);
5995
5996         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
5997         ret = btrfs_decompress(compress_type, tmp, page,
5998                                extent_offset, inline_size, max_size);
5999         if (ret) {
6000                 char *kaddr = kmap_atomic(page);
6001                 unsigned long copy_size = min_t(u64,
6002                                   PAGE_CACHE_SIZE - pg_offset,
6003                                   max_size - extent_offset);
6004                 memset(kaddr + pg_offset, 0, copy_size);
6005                 kunmap_atomic(kaddr);
6006         }
6007         kfree(tmp);
6008         return 0;
6009 }
6010
6011 /*
6012  * a bit scary, this does extent mapping from logical file offset to the disk.
6013  * the ugly parts come from merging extents from the disk with the in-ram
6014  * representation.  This gets more complex because of the data=ordered code,
6015  * where the in-ram extents might be locked pending data=ordered completion.
6016  *
6017  * This also copies inline extents directly into the page.
6018  */
6019
6020 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
6021                                     size_t pg_offset, u64 start, u64 len,
6022                                     int create)
6023 {
6024         int ret;
6025         int err = 0;
6026         u64 bytenr;
6027         u64 extent_start = 0;
6028         u64 extent_end = 0;
6029         u64 objectid = btrfs_ino(inode);
6030         u32 found_type;
6031         struct btrfs_path *path = NULL;
6032         struct btrfs_root *root = BTRFS_I(inode)->root;
6033         struct btrfs_file_extent_item *item;
6034         struct extent_buffer *leaf;
6035         struct btrfs_key found_key;
6036         struct extent_map *em = NULL;
6037         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
6038         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6039         struct btrfs_trans_handle *trans = NULL;
6040         int compress_type;
6041
6042 again:
6043         read_lock(&em_tree->lock);
6044         em = lookup_extent_mapping(em_tree, start, len);
6045         if (em)
6046                 em->bdev = root->fs_info->fs_devices->latest_bdev;
6047         read_unlock(&em_tree->lock);
6048
6049         if (em) {
6050                 if (em->start > start || em->start + em->len <= start)
6051                         free_extent_map(em);
6052                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6053                         free_extent_map(em);
6054                 else
6055                         goto out;
6056         }
6057         em = alloc_extent_map();
6058         if (!em) {
6059                 err = -ENOMEM;
6060                 goto out;
6061         }
6062         em->bdev = root->fs_info->fs_devices->latest_bdev;
6063         em->start = EXTENT_MAP_HOLE;
6064         em->orig_start = EXTENT_MAP_HOLE;
6065         em->len = (u64)-1;
6066         em->block_len = (u64)-1;
6067
6068         if (!path) {
6069                 path = btrfs_alloc_path();
6070                 if (!path) {
6071                         err = -ENOMEM;
6072                         goto out;
6073                 }
6074                 /*
6075                  * Chances are we'll be called again, so go ahead and do
6076                  * readahead
6077                  */
6078                 path->reada = 1;
6079         }
6080
6081         ret = btrfs_lookup_file_extent(trans, root, path,
6082                                        objectid, start, trans != NULL);
6083         if (ret < 0) {
6084                 err = ret;
6085                 goto out;
6086         }
6087
6088         if (ret != 0) {
6089                 if (path->slots[0] == 0)
6090                         goto not_found;
6091                 path->slots[0]--;
6092         }
6093
6094         leaf = path->nodes[0];
6095         item = btrfs_item_ptr(leaf, path->slots[0],
6096                               struct btrfs_file_extent_item);
6097         /* are we inside the extent that was found? */
6098         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6099         found_type = btrfs_key_type(&found_key);
6100         if (found_key.objectid != objectid ||
6101             found_type != BTRFS_EXTENT_DATA_KEY) {
6102                 /*
6103                  * If we backup past the first extent we want to move forward
6104                  * and see if there is an extent in front of us, otherwise we'll
6105                  * say there is a hole for our whole search range which can
6106                  * cause problems.
6107                  */
6108                 extent_end = start;
6109                 goto next;
6110         }
6111
6112         found_type = btrfs_file_extent_type(leaf, item);
6113         extent_start = found_key.offset;
6114         compress_type = btrfs_file_extent_compression(leaf, item);
6115         if (found_type == BTRFS_FILE_EXTENT_REG ||
6116             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6117                 extent_end = extent_start +
6118                        btrfs_file_extent_num_bytes(leaf, item);
6119         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6120                 size_t size;
6121                 size = btrfs_file_extent_inline_len(leaf, item);
6122                 extent_end = ALIGN(extent_start + size, root->sectorsize);
6123         }
6124 next:
6125         if (start >= extent_end) {
6126                 path->slots[0]++;
6127                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6128                         ret = btrfs_next_leaf(root, path);
6129                         if (ret < 0) {
6130                                 err = ret;
6131                                 goto out;
6132                         }
6133                         if (ret > 0)
6134                                 goto not_found;
6135                         leaf = path->nodes[0];
6136                 }
6137                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6138                 if (found_key.objectid != objectid ||
6139                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6140                         goto not_found;
6141                 if (start + len <= found_key.offset)
6142                         goto not_found;
6143                 em->start = start;
6144                 em->orig_start = start;
6145                 em->len = found_key.offset - start;
6146                 goto not_found_em;
6147         }
6148
6149         em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, item);
6150         if (found_type == BTRFS_FILE_EXTENT_REG ||
6151             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6152                 em->start = extent_start;
6153                 em->len = extent_end - extent_start;
6154                 em->orig_start = extent_start -
6155                                  btrfs_file_extent_offset(leaf, item);
6156                 em->orig_block_len = btrfs_file_extent_disk_num_bytes(leaf,
6157                                                                       item);
6158                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
6159                 if (bytenr == 0) {
6160                         em->block_start = EXTENT_MAP_HOLE;
6161                         goto insert;
6162                 }
6163                 if (compress_type != BTRFS_COMPRESS_NONE) {
6164                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
6165                         em->compress_type = compress_type;
6166                         em->block_start = bytenr;
6167                         em->block_len = em->orig_block_len;
6168                 } else {
6169                         bytenr += btrfs_file_extent_offset(leaf, item);
6170                         em->block_start = bytenr;
6171                         em->block_len = em->len;
6172                         if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
6173                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
6174                 }
6175                 goto insert;
6176         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6177                 unsigned long ptr;
6178                 char *map;
6179                 size_t size;
6180                 size_t extent_offset;
6181                 size_t copy_size;
6182
6183                 em->block_start = EXTENT_MAP_INLINE;
6184                 if (!page || create) {
6185                         em->start = extent_start;
6186                         em->len = extent_end - extent_start;
6187                         goto out;
6188                 }
6189
6190                 size = btrfs_file_extent_inline_len(leaf, item);
6191                 extent_offset = page_offset(page) + pg_offset - extent_start;
6192                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
6193                                 size - extent_offset);
6194                 em->start = extent_start + extent_offset;
6195                 em->len = ALIGN(copy_size, root->sectorsize);
6196                 em->orig_block_len = em->len;
6197                 em->orig_start = em->start;
6198                 if (compress_type) {
6199                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
6200                         em->compress_type = compress_type;
6201                 }
6202                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6203                 if (create == 0 && !PageUptodate(page)) {
6204                         if (btrfs_file_extent_compression(leaf, item) !=
6205                             BTRFS_COMPRESS_NONE) {
6206                                 ret = uncompress_inline(path, inode, page,
6207                                                         pg_offset,
6208                                                         extent_offset, item);
6209                                 BUG_ON(ret); /* -ENOMEM */
6210                         } else {
6211                                 map = kmap(page);
6212                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6213                                                    copy_size);
6214                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
6215                                         memset(map + pg_offset + copy_size, 0,
6216                                                PAGE_CACHE_SIZE - pg_offset -
6217                                                copy_size);
6218                                 }
6219                                 kunmap(page);
6220                         }
6221                         flush_dcache_page(page);
6222                 } else if (create && PageUptodate(page)) {
6223                         BUG();
6224                         if (!trans) {
6225                                 kunmap(page);
6226                                 free_extent_map(em);
6227                                 em = NULL;
6228
6229                                 btrfs_release_path(path);
6230                                 trans = btrfs_join_transaction(root);
6231
6232                                 if (IS_ERR(trans))
6233                                         return ERR_CAST(trans);
6234                                 goto again;
6235                         }
6236                         map = kmap(page);
6237                         write_extent_buffer(leaf, map + pg_offset, ptr,
6238                                             copy_size);
6239                         kunmap(page);
6240                         btrfs_mark_buffer_dirty(leaf);
6241                 }
6242                 set_extent_uptodate(io_tree, em->start,
6243                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6244                 goto insert;
6245         } else {
6246                 WARN(1, KERN_ERR "btrfs unknown found_type %d\n", found_type);
6247         }
6248 not_found:
6249         em->start = start;
6250         em->orig_start = start;
6251         em->len = len;
6252 not_found_em:
6253         em->block_start = EXTENT_MAP_HOLE;
6254         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
6255 insert:
6256         btrfs_release_path(path);
6257         if (em->start > start || extent_map_end(em) <= start) {
6258                 btrfs_err(root->fs_info, "bad extent! em: [%llu %llu] passed [%llu %llu]",
6259                         em->start, em->len, start, len);
6260                 err = -EIO;
6261                 goto out;
6262         }
6263
6264         err = 0;
6265         write_lock(&em_tree->lock);
6266         ret = add_extent_mapping(em_tree, em, 0);
6267         /* it is possible that someone inserted the extent into the tree
6268          * while we had the lock dropped.  It is also possible that
6269          * an overlapping map exists in the tree
6270          */
6271         if (ret == -EEXIST) {
6272                 struct extent_map *existing;
6273
6274                 ret = 0;
6275
6276                 existing = lookup_extent_mapping(em_tree, start, len);
6277                 if (existing && (existing->start > start ||
6278                     existing->start + existing->len <= start)) {
6279                         free_extent_map(existing);
6280                         existing = NULL;
6281                 }
6282                 if (!existing) {
6283                         existing = lookup_extent_mapping(em_tree, em->start,
6284                                                          em->len);
6285                         if (existing) {
6286                                 err = merge_extent_mapping(em_tree, existing,
6287                                                            em, start,
6288                                                            root->sectorsize);
6289                                 free_extent_map(existing);
6290                                 if (err) {
6291                                         free_extent_map(em);
6292                                         em = NULL;
6293                                 }
6294                         } else {
6295                                 err = -EIO;
6296                                 free_extent_map(em);
6297                                 em = NULL;
6298                         }
6299                 } else {
6300                         free_extent_map(em);
6301                         em = existing;
6302                         err = 0;
6303                 }
6304         }
6305         write_unlock(&em_tree->lock);
6306 out:
6307
6308         trace_btrfs_get_extent(root, em);
6309
6310         if (path)
6311                 btrfs_free_path(path);
6312         if (trans) {
6313                 ret = btrfs_end_transaction(trans, root);
6314                 if (!err)
6315                         err = ret;
6316         }
6317         if (err) {
6318                 free_extent_map(em);
6319                 return ERR_PTR(err);
6320         }
6321         BUG_ON(!em); /* Error is always set */
6322         return em;
6323 }
6324
6325 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
6326                                            size_t pg_offset, u64 start, u64 len,
6327                                            int create)
6328 {
6329         struct extent_map *em;
6330         struct extent_map *hole_em = NULL;
6331         u64 range_start = start;
6332         u64 end;
6333         u64 found;
6334         u64 found_end;
6335         int err = 0;
6336
6337         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
6338         if (IS_ERR(em))
6339                 return em;
6340         if (em) {
6341                 /*
6342                  * if our em maps to
6343                  * -  a hole or
6344                  * -  a pre-alloc extent,
6345                  * there might actually be delalloc bytes behind it.
6346                  */
6347                 if (em->block_start != EXTENT_MAP_HOLE &&
6348                     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6349                         return em;
6350                 else
6351                         hole_em = em;
6352         }
6353
6354         /* check to see if we've wrapped (len == -1 or similar) */
6355         end = start + len;
6356         if (end < start)
6357                 end = (u64)-1;
6358         else
6359                 end -= 1;
6360
6361         em = NULL;
6362
6363         /* ok, we didn't find anything, lets look for delalloc */
6364         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
6365                                  end, len, EXTENT_DELALLOC, 1);
6366         found_end = range_start + found;
6367         if (found_end < range_start)
6368                 found_end = (u64)-1;
6369
6370         /*
6371          * we didn't find anything useful, return
6372          * the original results from get_extent()
6373          */
6374         if (range_start > end || found_end <= start) {
6375                 em = hole_em;
6376                 hole_em = NULL;
6377                 goto out;
6378         }
6379
6380         /* adjust the range_start to make sure it doesn't
6381          * go backwards from the start they passed in
6382          */
6383         range_start = max(start, range_start);
6384         found = found_end - range_start;
6385
6386         if (found > 0) {
6387                 u64 hole_start = start;
6388                 u64 hole_len = len;
6389
6390                 em = alloc_extent_map();
6391                 if (!em) {
6392                         err = -ENOMEM;
6393                         goto out;
6394                 }
6395                 /*
6396                  * when btrfs_get_extent can't find anything it
6397                  * returns one huge hole
6398                  *
6399                  * make sure what it found really fits our range, and
6400                  * adjust to make sure it is based on the start from
6401                  * the caller
6402                  */
6403                 if (hole_em) {
6404                         u64 calc_end = extent_map_end(hole_em);
6405
6406                         if (calc_end <= start || (hole_em->start > end)) {
6407                                 free_extent_map(hole_em);
6408                                 hole_em = NULL;
6409                         } else {
6410                                 hole_start = max(hole_em->start, start);
6411                                 hole_len = calc_end - hole_start;
6412                         }
6413                 }
6414                 em->bdev = NULL;
6415                 if (hole_em && range_start > hole_start) {
6416                         /* our hole starts before our delalloc, so we
6417                          * have to return just the parts of the hole
6418                          * that go until  the delalloc starts
6419                          */
6420                         em->len = min(hole_len,
6421                                       range_start - hole_start);
6422                         em->start = hole_start;
6423                         em->orig_start = hole_start;
6424                         /*
6425                          * don't adjust block start at all,
6426                          * it is fixed at EXTENT_MAP_HOLE
6427                          */
6428                         em->block_start = hole_em->block_start;
6429                         em->block_len = hole_len;
6430                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
6431                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
6432                 } else {
6433                         em->start = range_start;
6434                         em->len = found;
6435                         em->orig_start = range_start;
6436                         em->block_start = EXTENT_MAP_DELALLOC;
6437                         em->block_len = found;
6438                 }
6439         } else if (hole_em) {
6440                 return hole_em;
6441         }
6442 out:
6443
6444         free_extent_map(hole_em);
6445         if (err) {
6446                 free_extent_map(em);
6447                 return ERR_PTR(err);
6448         }
6449         return em;
6450 }
6451
6452 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
6453                                                   u64 start, u64 len)
6454 {
6455         struct btrfs_root *root = BTRFS_I(inode)->root;
6456         struct extent_map *em;
6457         struct btrfs_key ins;
6458         u64 alloc_hint;
6459         int ret;
6460
6461         alloc_hint = get_extent_allocation_hint(inode, start, len);
6462         ret = btrfs_reserve_extent(root, len, root->sectorsize, 0,
6463                                    alloc_hint, &ins, 1);
6464         if (ret)
6465                 return ERR_PTR(ret);
6466
6467         em = create_pinned_em(inode, start, ins.offset, start, ins.objectid,
6468                               ins.offset, ins.offset, ins.offset, 0);
6469         if (IS_ERR(em)) {
6470                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
6471                 return em;
6472         }
6473
6474         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
6475                                            ins.offset, ins.offset, 0);
6476         if (ret) {
6477                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
6478                 free_extent_map(em);
6479                 return ERR_PTR(ret);
6480         }
6481
6482         return em;
6483 }
6484
6485 /*
6486  * returns 1 when the nocow is safe, < 1 on error, 0 if the
6487  * block must be cow'd
6488  */
6489 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
6490                               u64 *orig_start, u64 *orig_block_len,
6491                               u64 *ram_bytes)
6492 {
6493         struct btrfs_trans_handle *trans;
6494         struct btrfs_path *path;
6495         int ret;
6496         struct extent_buffer *leaf;
6497         struct btrfs_root *root = BTRFS_I(inode)->root;
6498         struct btrfs_file_extent_item *fi;
6499         struct btrfs_key key;
6500         u64 disk_bytenr;
6501         u64 backref_offset;
6502         u64 extent_end;
6503         u64 num_bytes;
6504         int slot;
6505         int found_type;
6506         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
6507         path = btrfs_alloc_path();
6508         if (!path)
6509                 return -ENOMEM;
6510
6511         ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode),
6512                                        offset, 0);
6513         if (ret < 0)
6514                 goto out;
6515
6516         slot = path->slots[0];
6517         if (ret == 1) {
6518                 if (slot == 0) {
6519                         /* can't find the item, must cow */
6520                         ret = 0;
6521                         goto out;
6522                 }
6523                 slot--;
6524         }
6525         ret = 0;
6526         leaf = path->nodes[0];
6527         btrfs_item_key_to_cpu(leaf, &key, slot);
6528         if (key.objectid != btrfs_ino(inode) ||
6529             key.type != BTRFS_EXTENT_DATA_KEY) {
6530                 /* not our file or wrong item type, must cow */
6531                 goto out;
6532         }
6533
6534         if (key.offset > offset) {
6535                 /* Wrong offset, must cow */
6536                 goto out;
6537         }
6538
6539         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
6540         found_type = btrfs_file_extent_type(leaf, fi);
6541         if (found_type != BTRFS_FILE_EXTENT_REG &&
6542             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
6543                 /* not a regular extent, must cow */
6544                 goto out;
6545         }
6546
6547         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
6548                 goto out;
6549
6550         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
6551         if (disk_bytenr == 0)
6552                 goto out;
6553
6554         if (btrfs_file_extent_compression(leaf, fi) ||
6555             btrfs_file_extent_encryption(leaf, fi) ||
6556             btrfs_file_extent_other_encoding(leaf, fi))
6557                 goto out;
6558
6559         backref_offset = btrfs_file_extent_offset(leaf, fi);
6560
6561         if (orig_start) {
6562                 *orig_start = key.offset - backref_offset;
6563                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
6564                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
6565         }
6566
6567         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
6568
6569         if (btrfs_extent_readonly(root, disk_bytenr))
6570                 goto out;
6571         btrfs_release_path(path);
6572
6573         /*
6574          * look for other files referencing this extent, if we
6575          * find any we must cow
6576          */
6577         trans = btrfs_join_transaction(root);
6578         if (IS_ERR(trans)) {
6579                 ret = 0;
6580                 goto out;
6581         }
6582
6583         ret = btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
6584                                     key.offset - backref_offset, disk_bytenr);
6585         btrfs_end_transaction(trans, root);
6586         if (ret) {
6587                 ret = 0;
6588                 goto out;
6589         }
6590
6591         /*
6592          * adjust disk_bytenr and num_bytes to cover just the bytes
6593          * in this extent we are about to write.  If there
6594          * are any csums in that range we have to cow in order
6595          * to keep the csums correct
6596          */
6597         disk_bytenr += backref_offset;
6598         disk_bytenr += offset - key.offset;
6599         num_bytes = min(offset + *len, extent_end) - offset;
6600         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
6601                                 goto out;
6602         /*
6603          * all of the above have passed, it is safe to overwrite this extent
6604          * without cow
6605          */
6606         *len = num_bytes;
6607         ret = 1;
6608 out:
6609         btrfs_free_path(path);
6610         return ret;
6611 }
6612
6613 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
6614                               struct extent_state **cached_state, int writing)
6615 {
6616         struct btrfs_ordered_extent *ordered;
6617         int ret = 0;
6618
6619         while (1) {
6620                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6621                                  0, cached_state);
6622                 /*
6623                  * We're concerned with the entire range that we're going to be
6624                  * doing DIO to, so we need to make sure theres no ordered
6625                  * extents in this range.
6626                  */
6627                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
6628                                                      lockend - lockstart + 1);
6629
6630                 /*
6631                  * We need to make sure there are no buffered pages in this
6632                  * range either, we could have raced between the invalidate in
6633                  * generic_file_direct_write and locking the extent.  The
6634                  * invalidate needs to happen so that reads after a write do not
6635                  * get stale data.
6636                  */
6637                 if (!ordered && (!writing ||
6638                     !test_range_bit(&BTRFS_I(inode)->io_tree,
6639                                     lockstart, lockend, EXTENT_UPTODATE, 0,
6640                                     *cached_state)))
6641                         break;
6642
6643                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6644                                      cached_state, GFP_NOFS);
6645
6646                 if (ordered) {
6647                         btrfs_start_ordered_extent(inode, ordered, 1);
6648                         btrfs_put_ordered_extent(ordered);
6649                 } else {
6650                         /* Screw you mmap */
6651                         ret = filemap_write_and_wait_range(inode->i_mapping,
6652                                                            lockstart,
6653                                                            lockend);
6654                         if (ret)
6655                                 break;
6656
6657                         /*
6658                          * If we found a page that couldn't be invalidated just
6659                          * fall back to buffered.
6660                          */
6661                         ret = invalidate_inode_pages2_range(inode->i_mapping,
6662                                         lockstart >> PAGE_CACHE_SHIFT,
6663                                         lockend >> PAGE_CACHE_SHIFT);
6664                         if (ret)
6665                                 break;
6666                 }
6667
6668                 cond_resched();
6669         }
6670
6671         return ret;
6672 }
6673
6674 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
6675                                            u64 len, u64 orig_start,
6676                                            u64 block_start, u64 block_len,
6677                                            u64 orig_block_len, u64 ram_bytes,
6678                                            int type)
6679 {
6680         struct extent_map_tree *em_tree;
6681         struct extent_map *em;
6682         struct btrfs_root *root = BTRFS_I(inode)->root;
6683         int ret;
6684
6685         em_tree = &BTRFS_I(inode)->extent_tree;
6686         em = alloc_extent_map();
6687         if (!em)
6688                 return ERR_PTR(-ENOMEM);
6689
6690         em->start = start;
6691         em->orig_start = orig_start;
6692         em->mod_start = start;
6693         em->mod_len = len;
6694         em->len = len;
6695         em->block_len = block_len;
6696         em->block_start = block_start;
6697         em->bdev = root->fs_info->fs_devices->latest_bdev;
6698         em->orig_block_len = orig_block_len;
6699         em->ram_bytes = ram_bytes;
6700         em->generation = -1;
6701         set_bit(EXTENT_FLAG_PINNED, &em->flags);
6702         if (type == BTRFS_ORDERED_PREALLOC)
6703                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
6704
6705         do {
6706                 btrfs_drop_extent_cache(inode, em->start,
6707                                 em->start + em->len - 1, 0);
6708                 write_lock(&em_tree->lock);
6709                 ret = add_extent_mapping(em_tree, em, 1);
6710                 write_unlock(&em_tree->lock);
6711         } while (ret == -EEXIST);
6712
6713         if (ret) {
6714                 free_extent_map(em);
6715                 return ERR_PTR(ret);
6716         }
6717
6718         return em;
6719 }
6720
6721
6722 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
6723                                    struct buffer_head *bh_result, int create)
6724 {
6725         struct extent_map *em;
6726         struct btrfs_root *root = BTRFS_I(inode)->root;
6727         struct extent_state *cached_state = NULL;
6728         u64 start = iblock << inode->i_blkbits;
6729         u64 lockstart, lockend;
6730         u64 len = bh_result->b_size;
6731         int unlock_bits = EXTENT_LOCKED;
6732         int ret = 0;
6733
6734         if (create)
6735                 unlock_bits |= EXTENT_DELALLOC | EXTENT_DIRTY;
6736         else
6737                 len = min_t(u64, len, root->sectorsize);
6738
6739         lockstart = start;
6740         lockend = start + len - 1;
6741
6742         /*
6743          * If this errors out it's because we couldn't invalidate pagecache for
6744          * this range and we need to fallback to buffered.
6745          */
6746         if (lock_extent_direct(inode, lockstart, lockend, &cached_state, create))
6747                 return -ENOTBLK;
6748
6749         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
6750         if (IS_ERR(em)) {
6751                 ret = PTR_ERR(em);
6752                 goto unlock_err;
6753         }
6754
6755         /*
6756          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
6757          * io.  INLINE is special, and we could probably kludge it in here, but
6758          * it's still buffered so for safety lets just fall back to the generic
6759          * buffered path.
6760          *
6761          * For COMPRESSED we _have_ to read the entire extent in so we can
6762          * decompress it, so there will be buffering required no matter what we
6763          * do, so go ahead and fallback to buffered.
6764          *
6765          * We return -ENOTBLK because thats what makes DIO go ahead and go back
6766          * to buffered IO.  Don't blame me, this is the price we pay for using
6767          * the generic code.
6768          */
6769         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
6770             em->block_start == EXTENT_MAP_INLINE) {
6771                 free_extent_map(em);
6772                 ret = -ENOTBLK;
6773                 goto unlock_err;
6774         }
6775
6776         /* Just a good old fashioned hole, return */
6777         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
6778                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
6779                 free_extent_map(em);
6780                 goto unlock_err;
6781         }
6782
6783         /*
6784          * We don't allocate a new extent in the following cases
6785          *
6786          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
6787          * existing extent.
6788          * 2) The extent is marked as PREALLOC.  We're good to go here and can
6789          * just use the extent.
6790          *
6791          */
6792         if (!create) {
6793                 len = min(len, em->len - (start - em->start));
6794                 lockstart = start + len;
6795                 goto unlock;
6796         }
6797
6798         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
6799             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
6800              em->block_start != EXTENT_MAP_HOLE)) {
6801                 int type;
6802                 int ret;
6803                 u64 block_start, orig_start, orig_block_len, ram_bytes;
6804
6805                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6806                         type = BTRFS_ORDERED_PREALLOC;
6807                 else
6808                         type = BTRFS_ORDERED_NOCOW;
6809                 len = min(len, em->len - (start - em->start));
6810                 block_start = em->block_start + (start - em->start);
6811
6812                 if (can_nocow_extent(inode, start, &len, &orig_start,
6813                                      &orig_block_len, &ram_bytes) == 1) {
6814                         if (type == BTRFS_ORDERED_PREALLOC) {
6815                                 free_extent_map(em);
6816                                 em = create_pinned_em(inode, start, len,
6817                                                        orig_start,
6818                                                        block_start, len,
6819                                                        orig_block_len,
6820                                                        ram_bytes, type);
6821                                 if (IS_ERR(em))
6822                                         goto unlock_err;
6823                         }
6824
6825                         ret = btrfs_add_ordered_extent_dio(inode, start,
6826                                            block_start, len, len, type);
6827                         if (ret) {
6828                                 free_extent_map(em);
6829                                 goto unlock_err;
6830                         }
6831                         goto unlock;
6832                 }
6833         }
6834
6835         /*
6836          * this will cow the extent, reset the len in case we changed
6837          * it above
6838          */
6839         len = bh_result->b_size;
6840         free_extent_map(em);
6841         em = btrfs_new_extent_direct(inode, start, len);
6842         if (IS_ERR(em)) {
6843                 ret = PTR_ERR(em);
6844                 goto unlock_err;
6845         }
6846         len = min(len, em->len - (start - em->start));
6847 unlock:
6848         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
6849                 inode->i_blkbits;
6850         bh_result->b_size = len;
6851         bh_result->b_bdev = em->bdev;
6852         set_buffer_mapped(bh_result);
6853         if (create) {
6854                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6855                         set_buffer_new(bh_result);
6856
6857                 /*
6858                  * Need to update the i_size under the extent lock so buffered
6859                  * readers will get the updated i_size when we unlock.
6860                  */
6861                 if (start + len > i_size_read(inode))
6862                         i_size_write(inode, start + len);
6863
6864                 spin_lock(&BTRFS_I(inode)->lock);
6865                 BTRFS_I(inode)->outstanding_extents++;
6866                 spin_unlock(&BTRFS_I(inode)->lock);
6867
6868                 ret = set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
6869                                      lockstart + len - 1, EXTENT_DELALLOC, NULL,
6870                                      &cached_state, GFP_NOFS);
6871                 BUG_ON(ret);
6872         }
6873
6874         /*
6875          * In the case of write we need to clear and unlock the entire range,
6876          * in the case of read we need to unlock only the end area that we
6877          * aren't using if there is any left over space.
6878          */
6879         if (lockstart < lockend) {
6880                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
6881                                  lockend, unlock_bits, 1, 0,
6882                                  &cached_state, GFP_NOFS);
6883         } else {
6884                 free_extent_state(cached_state);
6885         }
6886
6887         free_extent_map(em);
6888
6889         return 0;
6890
6891 unlock_err:
6892         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6893                          unlock_bits, 1, 0, &cached_state, GFP_NOFS);
6894         return ret;
6895 }
6896
6897 static void btrfs_endio_direct_read(struct bio *bio, int err)
6898 {
6899         struct btrfs_dio_private *dip = bio->bi_private;
6900         struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
6901         struct bio_vec *bvec = bio->bi_io_vec;
6902         struct inode *inode = dip->inode;
6903         struct btrfs_root *root = BTRFS_I(inode)->root;
6904         struct bio *dio_bio;
6905         u32 *csums = (u32 *)dip->csum;
6906         int index = 0;
6907         u64 start;
6908
6909         start = dip->logical_offset;
6910         do {
6911                 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
6912                         struct page *page = bvec->bv_page;
6913                         char *kaddr;
6914                         u32 csum = ~(u32)0;
6915                         unsigned long flags;
6916
6917                         local_irq_save(flags);
6918                         kaddr = kmap_atomic(page);
6919                         csum = btrfs_csum_data(kaddr + bvec->bv_offset,
6920                                                csum, bvec->bv_len);
6921                         btrfs_csum_final(csum, (char *)&csum);
6922                         kunmap_atomic(kaddr);
6923                         local_irq_restore(flags);
6924
6925                         flush_dcache_page(bvec->bv_page);
6926                         if (csum != csums[index]) {
6927                                 btrfs_err(root->fs_info, "csum failed ino %llu off %llu csum %u expected csum %u",
6928                                           btrfs_ino(inode), start, csum,
6929                                           csums[index]);
6930                                 err = -EIO;
6931                         }
6932                 }
6933
6934                 start += bvec->bv_len;
6935                 bvec++;
6936                 index++;
6937         } while (bvec <= bvec_end);
6938
6939         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
6940                       dip->logical_offset + dip->bytes - 1);
6941         dio_bio = dip->dio_bio;
6942
6943         kfree(dip);
6944
6945         /* If we had a csum failure make sure to clear the uptodate flag */
6946         if (err)
6947                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
6948         dio_end_io(dio_bio, err);
6949         bio_put(bio);
6950 }
6951
6952 static void btrfs_endio_direct_write(struct bio *bio, int err)
6953 {
6954         struct btrfs_dio_private *dip = bio->bi_private;
6955         struct inode *inode = dip->inode;
6956         struct btrfs_root *root = BTRFS_I(inode)->root;
6957         struct btrfs_ordered_extent *ordered = NULL;
6958         u64 ordered_offset = dip->logical_offset;
6959         u64 ordered_bytes = dip->bytes;
6960         struct bio *dio_bio;
6961         int ret;
6962
6963         if (err)
6964                 goto out_done;
6965 again:
6966         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
6967                                                    &ordered_offset,
6968                                                    ordered_bytes, !err);
6969         if (!ret)
6970                 goto out_test;
6971
6972         ordered->work.func = finish_ordered_fn;
6973         ordered->work.flags = 0;
6974         btrfs_queue_worker(&root->fs_info->endio_write_workers,
6975                            &ordered->work);
6976 out_test:
6977         /*
6978          * our bio might span multiple ordered extents.  If we haven't
6979          * completed the accounting for the whole dio, go back and try again
6980          */
6981         if (ordered_offset < dip->logical_offset + dip->bytes) {
6982                 ordered_bytes = dip->logical_offset + dip->bytes -
6983                         ordered_offset;
6984                 ordered = NULL;
6985                 goto again;
6986         }
6987 out_done:
6988         dio_bio = dip->dio_bio;
6989
6990         kfree(dip);
6991
6992         /* If we had an error make sure to clear the uptodate flag */
6993         if (err)
6994                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
6995         dio_end_io(dio_bio, err);
6996         bio_put(bio);
6997 }
6998
6999 static int __btrfs_submit_bio_start_direct_io(struct inode *inode, int rw,
7000                                     struct bio *bio, int mirror_num,
7001                                     unsigned long bio_flags, u64 offset)
7002 {
7003         int ret;
7004         struct btrfs_root *root = BTRFS_I(inode)->root;
7005         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
7006         BUG_ON(ret); /* -ENOMEM */
7007         return 0;
7008 }
7009
7010 static void btrfs_end_dio_bio(struct bio *bio, int err)
7011 {
7012         struct btrfs_dio_private *dip = bio->bi_private;
7013
7014         if (err) {
7015                 btrfs_err(BTRFS_I(dip->inode)->root->fs_info,
7016                           "direct IO failed ino %llu rw %lu sector %#Lx len %u err no %d",
7017                       btrfs_ino(dip->inode), bio->bi_rw,
7018                       (unsigned long long)bio->bi_sector, bio->bi_size, err);
7019                 dip->errors = 1;
7020
7021                 /*
7022                  * before atomic variable goto zero, we must make sure
7023                  * dip->errors is perceived to be set.
7024                  */
7025                 smp_mb__before_atomic_dec();
7026         }
7027
7028         /* if there are more bios still pending for this dio, just exit */
7029         if (!atomic_dec_and_test(&dip->pending_bios))
7030                 goto out;
7031
7032         if (dip->errors) {
7033                 bio_io_error(dip->orig_bio);
7034         } else {
7035                 set_bit(BIO_UPTODATE, &dip->dio_bio->bi_flags);
7036                 bio_endio(dip->orig_bio, 0);
7037         }
7038 out:
7039         bio_put(bio);
7040 }
7041
7042 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
7043                                        u64 first_sector, gfp_t gfp_flags)
7044 {
7045         int nr_vecs = bio_get_nr_vecs(bdev);
7046         return btrfs_bio_alloc(bdev, first_sector, nr_vecs, gfp_flags);
7047 }
7048
7049 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
7050                                          int rw, u64 file_offset, int skip_sum,
7051                                          int async_submit)
7052 {
7053         struct btrfs_dio_private *dip = bio->bi_private;
7054         int write = rw & REQ_WRITE;
7055         struct btrfs_root *root = BTRFS_I(inode)->root;
7056         int ret;
7057
7058         if (async_submit)
7059                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
7060
7061         bio_get(bio);
7062
7063         if (!write) {
7064                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
7065                 if (ret)
7066                         goto err;
7067         }
7068
7069         if (skip_sum)
7070                 goto map;
7071
7072         if (write && async_submit) {
7073                 ret = btrfs_wq_submit_bio(root->fs_info,
7074                                    inode, rw, bio, 0, 0,
7075                                    file_offset,
7076                                    __btrfs_submit_bio_start_direct_io,
7077                                    __btrfs_submit_bio_done);
7078                 goto err;
7079         } else if (write) {
7080                 /*
7081                  * If we aren't doing async submit, calculate the csum of the
7082                  * bio now.
7083                  */
7084                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
7085                 if (ret)
7086                         goto err;
7087         } else if (!skip_sum) {
7088                 ret = btrfs_lookup_bio_sums_dio(root, inode, dip, bio,
7089                                                 file_offset);
7090                 if (ret)
7091                         goto err;
7092         }
7093
7094 map:
7095         ret = btrfs_map_bio(root, rw, bio, 0, async_submit);
7096 err:
7097         bio_put(bio);
7098         return ret;
7099 }
7100
7101 static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
7102                                     int skip_sum)
7103 {
7104         struct inode *inode = dip->inode;
7105         struct btrfs_root *root = BTRFS_I(inode)->root;
7106         struct bio *bio;
7107         struct bio *orig_bio = dip->orig_bio;
7108         struct bio_vec *bvec = orig_bio->bi_io_vec;
7109         u64 start_sector = orig_bio->bi_sector;
7110         u64 file_offset = dip->logical_offset;
7111         u64 submit_len = 0;
7112         u64 map_length;
7113         int nr_pages = 0;
7114         int ret = 0;
7115         int async_submit = 0;
7116
7117         map_length = orig_bio->bi_size;
7118         ret = btrfs_map_block(root->fs_info, rw, start_sector << 9,
7119                               &map_length, NULL, 0);
7120         if (ret) {
7121                 bio_put(orig_bio);
7122                 return -EIO;
7123         }
7124
7125         if (map_length >= orig_bio->bi_size) {
7126                 bio = orig_bio;
7127                 goto submit;
7128         }
7129
7130         /* async crcs make it difficult to collect full stripe writes. */
7131         if (btrfs_get_alloc_profile(root, 1) &
7132             (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6))
7133                 async_submit = 0;
7134         else
7135                 async_submit = 1;
7136
7137         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
7138         if (!bio)
7139                 return -ENOMEM;
7140         bio->bi_private = dip;
7141         bio->bi_end_io = btrfs_end_dio_bio;
7142         atomic_inc(&dip->pending_bios);
7143
7144         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
7145                 if (unlikely(map_length < submit_len + bvec->bv_len ||
7146                     bio_add_page(bio, bvec->bv_page, bvec->bv_len,
7147                                  bvec->bv_offset) < bvec->bv_len)) {
7148                         /*
7149                          * inc the count before we submit the bio so
7150                          * we know the end IO handler won't happen before
7151                          * we inc the count. Otherwise, the dip might get freed
7152                          * before we're done setting it up
7153                          */
7154                         atomic_inc(&dip->pending_bios);
7155                         ret = __btrfs_submit_dio_bio(bio, inode, rw,
7156                                                      file_offset, skip_sum,
7157                                                      async_submit);
7158                         if (ret) {
7159                                 bio_put(bio);
7160                                 atomic_dec(&dip->pending_bios);
7161                                 goto out_err;
7162                         }
7163
7164                         start_sector += submit_len >> 9;
7165                         file_offset += submit_len;
7166
7167                         submit_len = 0;
7168                         nr_pages = 0;
7169
7170                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
7171                                                   start_sector, GFP_NOFS);
7172                         if (!bio)
7173                                 goto out_err;
7174                         bio->bi_private = dip;
7175                         bio->bi_end_io = btrfs_end_dio_bio;
7176
7177                         map_length = orig_bio->bi_size;
7178                         ret = btrfs_map_block(root->fs_info, rw,
7179                                               start_sector << 9,
7180                                               &map_length, NULL, 0);
7181                         if (ret) {
7182                                 bio_put(bio);
7183                                 goto out_err;
7184                         }
7185                 } else {
7186                         submit_len += bvec->bv_len;
7187                         nr_pages++;
7188                         bvec++;
7189                 }
7190         }
7191
7192 submit:
7193         ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum,
7194                                      async_submit);
7195         if (!ret)
7196                 return 0;
7197
7198         bio_put(bio);
7199 out_err:
7200         dip->errors = 1;
7201         /*
7202          * before atomic variable goto zero, we must
7203          * make sure dip->errors is perceived to be set.
7204          */
7205         smp_mb__before_atomic_dec();
7206         if (atomic_dec_and_test(&dip->pending_bios))
7207                 bio_io_error(dip->orig_bio);
7208
7209         /* bio_end_io() will handle error, so we needn't return it */
7210         return 0;
7211 }
7212
7213 static void btrfs_submit_direct(int rw, struct bio *dio_bio,
7214                                 struct inode *inode, loff_t file_offset)
7215 {
7216         struct btrfs_root *root = BTRFS_I(inode)->root;
7217         struct btrfs_dio_private *dip;
7218         struct bio *io_bio;
7219         int skip_sum;
7220         int sum_len;
7221         int write = rw & REQ_WRITE;
7222         int ret = 0;
7223         u16 csum_size;
7224
7225         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
7226
7227         io_bio = btrfs_bio_clone(dio_bio, GFP_NOFS);
7228         if (!io_bio) {
7229                 ret = -ENOMEM;
7230                 goto free_ordered;
7231         }
7232
7233         if (!skip_sum && !write) {
7234                 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
7235                 sum_len = dio_bio->bi_size >> inode->i_sb->s_blocksize_bits;
7236                 sum_len *= csum_size;
7237         } else {
7238                 sum_len = 0;
7239         }
7240
7241         dip = kmalloc(sizeof(*dip) + sum_len, GFP_NOFS);
7242         if (!dip) {
7243                 ret = -ENOMEM;
7244                 goto free_io_bio;
7245         }
7246
7247         dip->private = dio_bio->bi_private;
7248         dip->inode = inode;
7249         dip->logical_offset = file_offset;
7250         dip->bytes = dio_bio->bi_size;
7251         dip->disk_bytenr = (u64)dio_bio->bi_sector << 9;
7252         io_bio->bi_private = dip;
7253         dip->errors = 0;
7254         dip->orig_bio = io_bio;
7255         dip->dio_bio = dio_bio;
7256         atomic_set(&dip->pending_bios, 0);
7257
7258         if (write)
7259                 io_bio->bi_end_io = btrfs_endio_direct_write;
7260         else
7261                 io_bio->bi_end_io = btrfs_endio_direct_read;
7262
7263         ret = btrfs_submit_direct_hook(rw, dip, skip_sum);
7264         if (!ret)
7265                 return;
7266
7267 free_io_bio:
7268         bio_put(io_bio);
7269
7270 free_ordered:
7271         /*
7272          * If this is a write, we need to clean up the reserved space and kill
7273          * the ordered extent.
7274          */
7275         if (write) {
7276                 struct btrfs_ordered_extent *ordered;
7277                 ordered = btrfs_lookup_ordered_extent(inode, file_offset);
7278                 if (!test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags) &&
7279                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags))
7280                         btrfs_free_reserved_extent(root, ordered->start,
7281                                                    ordered->disk_len);
7282                 btrfs_put_ordered_extent(ordered);
7283                 btrfs_put_ordered_extent(ordered);
7284         }
7285         bio_endio(dio_bio, ret);
7286 }
7287
7288 static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *iocb,
7289                         const struct iovec *iov, loff_t offset,
7290                         unsigned long nr_segs)
7291 {
7292         int seg;
7293         int i;
7294         size_t size;
7295         unsigned long addr;
7296         unsigned blocksize_mask = root->sectorsize - 1;
7297         ssize_t retval = -EINVAL;
7298         loff_t end = offset;
7299
7300         if (offset & blocksize_mask)
7301                 goto out;
7302
7303         /* Check the memory alignment.  Blocks cannot straddle pages */
7304         for (seg = 0; seg < nr_segs; seg++) {
7305                 addr = (unsigned long)iov[seg].iov_base;
7306                 size = iov[seg].iov_len;
7307                 end += size;
7308                 if ((addr & blocksize_mask) || (size & blocksize_mask))
7309                         goto out;
7310
7311                 /* If this is a write we don't need to check anymore */
7312                 if (rw & WRITE)
7313                         continue;
7314
7315                 /*
7316                  * Check to make sure we don't have duplicate iov_base's in this
7317                  * iovec, if so return EINVAL, otherwise we'll get csum errors
7318                  * when reading back.
7319                  */
7320                 for (i = seg + 1; i < nr_segs; i++) {
7321                         if (iov[seg].iov_base == iov[i].iov_base)
7322                                 goto out;
7323                 }
7324         }
7325         retval = 0;
7326 out:
7327         return retval;
7328 }
7329
7330 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
7331                         const struct iovec *iov, loff_t offset,
7332                         unsigned long nr_segs)
7333 {
7334         struct file *file = iocb->ki_filp;
7335         struct inode *inode = file->f_mapping->host;
7336         size_t count = 0;
7337         int flags = 0;
7338         bool wakeup = true;
7339         bool relock = false;
7340         ssize_t ret;
7341
7342         if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iov,
7343                             offset, nr_segs))
7344                 return 0;
7345
7346         atomic_inc(&inode->i_dio_count);
7347         smp_mb__after_atomic_inc();
7348
7349         /*
7350          * The generic stuff only does filemap_write_and_wait_range, which isn't
7351          * enough if we've written compressed pages to this area, so we need to
7352          * call btrfs_wait_ordered_range to make absolutely sure that any
7353          * outstanding dirty pages are on disk.
7354          */
7355         count = iov_length(iov, nr_segs);
7356         ret = btrfs_wait_ordered_range(inode, offset, count);
7357         if (ret)
7358                 return ret;
7359
7360         if (rw & WRITE) {
7361                 /*
7362                  * If the write DIO is beyond the EOF, we need update
7363                  * the isize, but it is protected by i_mutex. So we can
7364                  * not unlock the i_mutex at this case.
7365                  */
7366                 if (offset + count <= inode->i_size) {
7367                         mutex_unlock(&inode->i_mutex);
7368                         relock = true;
7369                 }
7370                 ret = btrfs_delalloc_reserve_space(inode, count);
7371                 if (ret)
7372                         goto out;
7373         } else if (unlikely(test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
7374                                      &BTRFS_I(inode)->runtime_flags))) {
7375                 inode_dio_done(inode);
7376                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
7377                 wakeup = false;
7378         }
7379
7380         ret = __blockdev_direct_IO(rw, iocb, inode,
7381                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
7382                         iov, offset, nr_segs, btrfs_get_blocks_direct, NULL,
7383                         btrfs_submit_direct, flags);
7384         if (rw & WRITE) {
7385                 if (ret < 0 && ret != -EIOCBQUEUED)
7386                         btrfs_delalloc_release_space(inode, count);
7387                 else if (ret >= 0 && (size_t)ret < count)
7388                         btrfs_delalloc_release_space(inode,
7389                                                      count - (size_t)ret);
7390                 else
7391                         btrfs_delalloc_release_metadata(inode, 0);
7392         }
7393 out:
7394         if (wakeup)
7395                 inode_dio_done(inode);
7396         if (relock)
7397                 mutex_lock(&inode->i_mutex);
7398
7399         return ret;
7400 }
7401
7402 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
7403
7404 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
7405                 __u64 start, __u64 len)
7406 {
7407         int     ret;
7408
7409         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
7410         if (ret)
7411                 return ret;
7412
7413         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
7414 }
7415
7416 int btrfs_readpage(struct file *file, struct page *page)
7417 {
7418         struct extent_io_tree *tree;
7419         tree = &BTRFS_I(page->mapping->host)->io_tree;
7420         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
7421 }
7422
7423 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
7424 {
7425         struct extent_io_tree *tree;
7426
7427
7428         if (current->flags & PF_MEMALLOC) {
7429                 redirty_page_for_writepage(wbc, page);
7430                 unlock_page(page);
7431                 return 0;
7432         }
7433         tree = &BTRFS_I(page->mapping->host)->io_tree;
7434         return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
7435 }
7436
7437 static int btrfs_writepages(struct address_space *mapping,
7438                             struct writeback_control *wbc)
7439 {
7440         struct extent_io_tree *tree;
7441
7442         tree = &BTRFS_I(mapping->host)->io_tree;
7443         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
7444 }
7445
7446 static int
7447 btrfs_readpages(struct file *file, struct address_space *mapping,
7448                 struct list_head *pages, unsigned nr_pages)
7449 {
7450         struct extent_io_tree *tree;
7451         tree = &BTRFS_I(mapping->host)->io_tree;
7452         return extent_readpages(tree, mapping, pages, nr_pages,
7453                                 btrfs_get_extent);
7454 }
7455 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
7456 {
7457         struct extent_io_tree *tree;
7458         struct extent_map_tree *map;
7459         int ret;
7460
7461         tree = &BTRFS_I(page->mapping->host)->io_tree;
7462         map = &BTRFS_I(page->mapping->host)->extent_tree;
7463         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
7464         if (ret == 1) {
7465                 ClearPagePrivate(page);
7466                 set_page_private(page, 0);
7467                 page_cache_release(page);
7468         }
7469         return ret;
7470 }
7471
7472 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
7473 {
7474         if (PageWriteback(page) || PageDirty(page))
7475                 return 0;
7476         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
7477 }
7478
7479 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
7480                                  unsigned int length)
7481 {
7482         struct inode *inode = page->mapping->host;
7483         struct extent_io_tree *tree;
7484         struct btrfs_ordered_extent *ordered;
7485         struct extent_state *cached_state = NULL;
7486         u64 page_start = page_offset(page);
7487         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
7488         int inode_evicting = inode->i_state & I_FREEING;
7489
7490         /*
7491          * we have the page locked, so new writeback can't start,
7492          * and the dirty bit won't be cleared while we are here.
7493          *
7494          * Wait for IO on this page so that we can safely clear
7495          * the PagePrivate2 bit and do ordered accounting
7496          */
7497         wait_on_page_writeback(page);
7498
7499         tree = &BTRFS_I(inode)->io_tree;
7500         if (offset) {
7501                 btrfs_releasepage(page, GFP_NOFS);
7502                 return;
7503         }
7504
7505         if (!inode_evicting)
7506                 lock_extent_bits(tree, page_start, page_end, 0, &cached_state);
7507         ordered = btrfs_lookup_ordered_extent(inode, page_start);
7508         if (ordered) {
7509                 /*
7510                  * IO on this page will never be started, so we need
7511                  * to account for any ordered extents now
7512                  */
7513                 if (!inode_evicting)
7514                         clear_extent_bit(tree, page_start, page_end,
7515                                          EXTENT_DIRTY | EXTENT_DELALLOC |
7516                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
7517                                          EXTENT_DEFRAG, 1, 0, &cached_state,
7518                                          GFP_NOFS);
7519                 /*
7520                  * whoever cleared the private bit is responsible
7521                  * for the finish_ordered_io
7522                  */
7523                 if (TestClearPagePrivate2(page)) {
7524                         struct btrfs_ordered_inode_tree *tree;
7525                         u64 new_len;
7526
7527                         tree = &BTRFS_I(inode)->ordered_tree;
7528
7529                         spin_lock_irq(&tree->lock);
7530                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
7531                         new_len = page_start - ordered->file_offset;
7532                         if (new_len < ordered->truncated_len)
7533                                 ordered->truncated_len = new_len;
7534                         spin_unlock_irq(&tree->lock);
7535
7536                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
7537                                                            page_start,
7538                                                            PAGE_CACHE_SIZE, 1))
7539                                 btrfs_finish_ordered_io(ordered);
7540                 }
7541                 btrfs_put_ordered_extent(ordered);
7542                 if (!inode_evicting) {
7543                         cached_state = NULL;
7544                         lock_extent_bits(tree, page_start, page_end, 0,
7545                                          &cached_state);
7546                 }
7547         }
7548
7549         if (!inode_evicting) {
7550                 clear_extent_bit(tree, page_start, page_end,
7551                                  EXTENT_LOCKED | EXTENT_DIRTY |
7552                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
7553                                  EXTENT_DEFRAG, 1, 1,
7554                                  &cached_state, GFP_NOFS);
7555
7556                 __btrfs_releasepage(page, GFP_NOFS);
7557         }
7558
7559         ClearPageChecked(page);
7560         if (PagePrivate(page)) {
7561                 ClearPagePrivate(page);
7562                 set_page_private(page, 0);
7563                 page_cache_release(page);
7564         }
7565 }
7566
7567 /*
7568  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
7569  * called from a page fault handler when a page is first dirtied. Hence we must
7570  * be careful to check for EOF conditions here. We set the page up correctly
7571  * for a written page which means we get ENOSPC checking when writing into
7572  * holes and correct delalloc and unwritten extent mapping on filesystems that
7573  * support these features.
7574  *
7575  * We are not allowed to take the i_mutex here so we have to play games to
7576  * protect against truncate races as the page could now be beyond EOF.  Because
7577  * vmtruncate() writes the inode size before removing pages, once we have the
7578  * page lock we can determine safely if the page is beyond EOF. If it is not
7579  * beyond EOF, then the page is guaranteed safe against truncation until we
7580  * unlock the page.
7581  */
7582 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
7583 {
7584         struct page *page = vmf->page;
7585         struct inode *inode = file_inode(vma->vm_file);
7586         struct btrfs_root *root = BTRFS_I(inode)->root;
7587         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7588         struct btrfs_ordered_extent *ordered;
7589         struct extent_state *cached_state = NULL;
7590         char *kaddr;
7591         unsigned long zero_start;
7592         loff_t size;
7593         int ret;
7594         int reserved = 0;
7595         u64 page_start;
7596         u64 page_end;
7597
7598         sb_start_pagefault(inode->i_sb);
7599         ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
7600         if (!ret) {
7601                 ret = file_update_time(vma->vm_file);
7602                 reserved = 1;
7603         }
7604         if (ret) {
7605                 if (ret == -ENOMEM)
7606                         ret = VM_FAULT_OOM;
7607                 else /* -ENOSPC, -EIO, etc */
7608                         ret = VM_FAULT_SIGBUS;
7609                 if (reserved)
7610                         goto out;
7611                 goto out_noreserve;
7612         }
7613
7614         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
7615 again:
7616         lock_page(page);
7617         size = i_size_read(inode);
7618         page_start = page_offset(page);
7619         page_end = page_start + PAGE_CACHE_SIZE - 1;
7620
7621         if ((page->mapping != inode->i_mapping) ||
7622             (page_start >= size)) {
7623                 /* page got truncated out from underneath us */
7624                 goto out_unlock;
7625         }
7626         wait_on_page_writeback(page);
7627
7628         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
7629         set_page_extent_mapped(page);
7630
7631         /*
7632          * we can't set the delalloc bits if there are pending ordered
7633          * extents.  Drop our locks and wait for them to finish
7634          */
7635         ordered = btrfs_lookup_ordered_extent(inode, page_start);
7636         if (ordered) {
7637                 unlock_extent_cached(io_tree, page_start, page_end,
7638                                      &cached_state, GFP_NOFS);
7639                 unlock_page(page);
7640                 btrfs_start_ordered_extent(inode, ordered, 1);
7641                 btrfs_put_ordered_extent(ordered);
7642                 goto again;
7643         }
7644
7645         /*
7646          * XXX - page_mkwrite gets called every time the page is dirtied, even
7647          * if it was already dirty, so for space accounting reasons we need to
7648          * clear any delalloc bits for the range we are fixing to save.  There
7649          * is probably a better way to do this, but for now keep consistent with
7650          * prepare_pages in the normal write path.
7651          */
7652         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
7653                           EXTENT_DIRTY | EXTENT_DELALLOC |
7654                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
7655                           0, 0, &cached_state, GFP_NOFS);
7656
7657         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
7658                                         &cached_state);
7659         if (ret) {
7660                 unlock_extent_cached(io_tree, page_start, page_end,
7661                                      &cached_state, GFP_NOFS);
7662                 ret = VM_FAULT_SIGBUS;
7663                 goto out_unlock;
7664         }
7665         ret = 0;
7666
7667         /* page is wholly or partially inside EOF */
7668         if (page_start + PAGE_CACHE_SIZE > size)
7669                 zero_start = size & ~PAGE_CACHE_MASK;
7670         else
7671                 zero_start = PAGE_CACHE_SIZE;
7672
7673         if (zero_start != PAGE_CACHE_SIZE) {
7674                 kaddr = kmap(page);
7675                 memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
7676                 flush_dcache_page(page);
7677                 kunmap(page);
7678         }
7679         ClearPageChecked(page);
7680         set_page_dirty(page);
7681         SetPageUptodate(page);
7682
7683         BTRFS_I(inode)->last_trans = root->fs_info->generation;
7684         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
7685         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
7686
7687         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
7688
7689 out_unlock:
7690         if (!ret) {
7691                 sb_end_pagefault(inode->i_sb);
7692                 return VM_FAULT_LOCKED;
7693         }
7694         unlock_page(page);
7695 out:
7696         btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
7697 out_noreserve:
7698         sb_end_pagefault(inode->i_sb);
7699         return ret;
7700 }
7701
7702 static int btrfs_truncate(struct inode *inode)
7703 {
7704         struct btrfs_root *root = BTRFS_I(inode)->root;
7705         struct btrfs_block_rsv *rsv;
7706         int ret = 0;
7707         int err = 0;
7708         struct btrfs_trans_handle *trans;
7709         u64 mask = root->sectorsize - 1;
7710         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
7711
7712         ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
7713                                        (u64)-1);
7714         if (ret)
7715                 return ret;
7716
7717         /*
7718          * Yes ladies and gentelment, this is indeed ugly.  The fact is we have
7719          * 3 things going on here
7720          *
7721          * 1) We need to reserve space for our orphan item and the space to
7722          * delete our orphan item.  Lord knows we don't want to have a dangling
7723          * orphan item because we didn't reserve space to remove it.
7724          *
7725          * 2) We need to reserve space to update our inode.
7726          *
7727          * 3) We need to have something to cache all the space that is going to
7728          * be free'd up by the truncate operation, but also have some slack
7729          * space reserved in case it uses space during the truncate (thank you
7730          * very much snapshotting).
7731          *
7732          * And we need these to all be seperate.  The fact is we can use alot of
7733          * space doing the truncate, and we have no earthly idea how much space
7734          * we will use, so we need the truncate reservation to be seperate so it
7735          * doesn't end up using space reserved for updating the inode or
7736          * removing the orphan item.  We also need to be able to stop the
7737          * transaction and start a new one, which means we need to be able to
7738          * update the inode several times, and we have no idea of knowing how
7739          * many times that will be, so we can't just reserve 1 item for the
7740          * entirety of the opration, so that has to be done seperately as well.
7741          * Then there is the orphan item, which does indeed need to be held on
7742          * to for the whole operation, and we need nobody to touch this reserved
7743          * space except the orphan code.
7744          *
7745          * So that leaves us with
7746          *
7747          * 1) root->orphan_block_rsv - for the orphan deletion.
7748          * 2) rsv - for the truncate reservation, which we will steal from the
7749          * transaction reservation.
7750          * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
7751          * updating the inode.
7752          */
7753         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
7754         if (!rsv)
7755                 return -ENOMEM;
7756         rsv->size = min_size;
7757         rsv->failfast = 1;
7758
7759         /*
7760          * 1 for the truncate slack space
7761          * 1 for updating the inode.
7762          */
7763         trans = btrfs_start_transaction(root, 2);
7764         if (IS_ERR(trans)) {
7765                 err = PTR_ERR(trans);
7766                 goto out;
7767         }
7768
7769         /* Migrate the slack space for the truncate to our reserve */
7770         ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
7771                                       min_size);
7772         BUG_ON(ret);
7773
7774         /*
7775          * setattr is responsible for setting the ordered_data_close flag,
7776          * but that is only tested during the last file release.  That
7777          * could happen well after the next commit, leaving a great big
7778          * window where new writes may get lost if someone chooses to write
7779          * to this file after truncating to zero
7780          *
7781          * The inode doesn't have any dirty data here, and so if we commit
7782          * this is a noop.  If someone immediately starts writing to the inode
7783          * it is very likely we'll catch some of their writes in this
7784          * transaction, and the commit will find this file on the ordered
7785          * data list with good things to send down.
7786          *
7787          * This is a best effort solution, there is still a window where
7788          * using truncate to replace the contents of the file will
7789          * end up with a zero length file after a crash.
7790          */
7791         if (inode->i_size == 0 && test_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
7792                                            &BTRFS_I(inode)->runtime_flags))
7793                 btrfs_add_ordered_operation(trans, root, inode);
7794
7795         /*
7796          * So if we truncate and then write and fsync we normally would just
7797          * write the extents that changed, which is a problem if we need to
7798          * first truncate that entire inode.  So set this flag so we write out
7799          * all of the extents in the inode to the sync log so we're completely
7800          * safe.
7801          */
7802         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
7803         trans->block_rsv = rsv;
7804
7805         while (1) {
7806                 ret = btrfs_truncate_inode_items(trans, root, inode,
7807                                                  inode->i_size,
7808                                                  BTRFS_EXTENT_DATA_KEY);
7809                 if (ret != -ENOSPC) {
7810                         err = ret;
7811                         break;
7812                 }
7813
7814                 trans->block_rsv = &root->fs_info->trans_block_rsv;
7815                 ret = btrfs_update_inode(trans, root, inode);
7816                 if (ret) {
7817                         err = ret;
7818                         break;
7819                 }
7820
7821                 btrfs_end_transaction(trans, root);
7822                 btrfs_btree_balance_dirty(root);
7823
7824                 trans = btrfs_start_transaction(root, 2);
7825                 if (IS_ERR(trans)) {
7826                         ret = err = PTR_ERR(trans);
7827                         trans = NULL;
7828                         break;
7829                 }
7830
7831                 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
7832                                               rsv, min_size);
7833                 BUG_ON(ret);    /* shouldn't happen */
7834                 trans->block_rsv = rsv;
7835         }
7836
7837         if (ret == 0 && inode->i_nlink > 0) {
7838                 trans->block_rsv = root->orphan_block_rsv;
7839                 ret = btrfs_orphan_del(trans, inode);
7840                 if (ret)
7841                         err = ret;
7842         }
7843
7844         if (trans) {
7845                 trans->block_rsv = &root->fs_info->trans_block_rsv;
7846                 ret = btrfs_update_inode(trans, root, inode);
7847                 if (ret && !err)
7848                         err = ret;
7849
7850                 ret = btrfs_end_transaction(trans, root);
7851                 btrfs_btree_balance_dirty(root);
7852         }
7853
7854 out:
7855         btrfs_free_block_rsv(root, rsv);
7856
7857         if (ret && !err)
7858                 err = ret;
7859
7860         return err;
7861 }
7862
7863 /*
7864  * create a new subvolume directory/inode (helper for the ioctl).
7865  */
7866 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
7867                              struct btrfs_root *new_root, u64 new_dirid)
7868 {
7869         struct inode *inode;
7870         int err;
7871         u64 index = 0;
7872
7873         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
7874                                 new_dirid, new_dirid,
7875                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
7876                                 &index);
7877         if (IS_ERR(inode))
7878                 return PTR_ERR(inode);
7879         inode->i_op = &btrfs_dir_inode_operations;
7880         inode->i_fop = &btrfs_dir_file_operations;
7881
7882         set_nlink(inode, 1);
7883         btrfs_i_size_write(inode, 0);
7884
7885         err = btrfs_update_inode(trans, new_root, inode);
7886
7887         iput(inode);
7888         return err;
7889 }
7890
7891 struct inode *btrfs_alloc_inode(struct super_block *sb)
7892 {
7893         struct btrfs_inode *ei;
7894         struct inode *inode;
7895
7896         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
7897         if (!ei)
7898                 return NULL;
7899
7900         ei->root = NULL;
7901         ei->generation = 0;
7902         ei->last_trans = 0;
7903         ei->last_sub_trans = 0;
7904         ei->logged_trans = 0;
7905         ei->delalloc_bytes = 0;
7906         ei->disk_i_size = 0;
7907         ei->flags = 0;
7908         ei->csum_bytes = 0;
7909         ei->index_cnt = (u64)-1;
7910         ei->dir_index = 0;
7911         ei->last_unlink_trans = 0;
7912         ei->last_log_commit = 0;
7913
7914         spin_lock_init(&ei->lock);
7915         ei->outstanding_extents = 0;
7916         ei->reserved_extents = 0;
7917
7918         ei->runtime_flags = 0;
7919         ei->force_compress = BTRFS_COMPRESS_NONE;
7920
7921         ei->delayed_node = NULL;
7922
7923         inode = &ei->vfs_inode;
7924         extent_map_tree_init(&ei->extent_tree);
7925         extent_io_tree_init(&ei->io_tree, &inode->i_data);
7926         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
7927         ei->io_tree.track_uptodate = 1;
7928         ei->io_failure_tree.track_uptodate = 1;
7929         atomic_set(&ei->sync_writers, 0);
7930         mutex_init(&ei->log_mutex);
7931         mutex_init(&ei->delalloc_mutex);
7932         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
7933         INIT_LIST_HEAD(&ei->delalloc_inodes);
7934         INIT_LIST_HEAD(&ei->ordered_operations);
7935         RB_CLEAR_NODE(&ei->rb_node);
7936
7937         return inode;
7938 }
7939
7940 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
7941 void btrfs_test_destroy_inode(struct inode *inode)
7942 {
7943         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
7944         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
7945 }
7946 #endif
7947
7948 static void btrfs_i_callback(struct rcu_head *head)
7949 {
7950         struct inode *inode = container_of(head, struct inode, i_rcu);
7951         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
7952 }
7953
7954 void btrfs_destroy_inode(struct inode *inode)
7955 {
7956         struct btrfs_ordered_extent *ordered;
7957         struct btrfs_root *root = BTRFS_I(inode)->root;
7958
7959         WARN_ON(!hlist_empty(&inode->i_dentry));
7960         WARN_ON(inode->i_data.nrpages);
7961         WARN_ON(BTRFS_I(inode)->outstanding_extents);
7962         WARN_ON(BTRFS_I(inode)->reserved_extents);
7963         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
7964         WARN_ON(BTRFS_I(inode)->csum_bytes);
7965
7966         /*
7967          * This can happen where we create an inode, but somebody else also
7968          * created the same inode and we need to destroy the one we already
7969          * created.
7970          */
7971         if (!root)
7972                 goto free;
7973
7974         /*
7975          * Make sure we're properly removed from the ordered operation
7976          * lists.
7977          */
7978         smp_mb();
7979         if (!list_empty(&BTRFS_I(inode)->ordered_operations)) {
7980                 spin_lock(&root->fs_info->ordered_root_lock);
7981                 list_del_init(&BTRFS_I(inode)->ordered_operations);
7982                 spin_unlock(&root->fs_info->ordered_root_lock);
7983         }
7984
7985         if (test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
7986                      &BTRFS_I(inode)->runtime_flags)) {
7987                 btrfs_info(root->fs_info, "inode %llu still on the orphan list",
7988                         btrfs_ino(inode));
7989                 atomic_dec(&root->orphan_inodes);
7990         }
7991
7992         while (1) {
7993                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
7994                 if (!ordered)
7995                         break;
7996                 else {
7997                         btrfs_err(root->fs_info, "found ordered extent %llu %llu on inode cleanup",
7998                                 ordered->file_offset, ordered->len);
7999                         btrfs_remove_ordered_extent(inode, ordered);
8000                         btrfs_put_ordered_extent(ordered);
8001                         btrfs_put_ordered_extent(ordered);
8002                 }
8003         }
8004         inode_tree_del(inode);
8005         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8006 free:
8007         call_rcu(&inode->i_rcu, btrfs_i_callback);
8008 }
8009
8010 int btrfs_drop_inode(struct inode *inode)
8011 {
8012         struct btrfs_root *root = BTRFS_I(inode)->root;
8013
8014         if (root == NULL)
8015                 return 1;
8016
8017         /* the snap/subvol tree is on deleting */
8018         if (btrfs_root_refs(&root->root_item) == 0)
8019                 return 1;
8020         else
8021                 return generic_drop_inode(inode);
8022 }
8023
8024 static void init_once(void *foo)
8025 {
8026         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
8027
8028         inode_init_once(&ei->vfs_inode);
8029 }
8030
8031 void btrfs_destroy_cachep(void)
8032 {
8033         /*
8034          * Make sure all delayed rcu free inodes are flushed before we
8035          * destroy cache.
8036          */
8037         rcu_barrier();
8038         if (btrfs_inode_cachep)
8039                 kmem_cache_destroy(btrfs_inode_cachep);
8040         if (btrfs_trans_handle_cachep)
8041                 kmem_cache_destroy(btrfs_trans_handle_cachep);
8042         if (btrfs_transaction_cachep)
8043                 kmem_cache_destroy(btrfs_transaction_cachep);
8044         if (btrfs_path_cachep)
8045                 kmem_cache_destroy(btrfs_path_cachep);
8046         if (btrfs_free_space_cachep)
8047                 kmem_cache_destroy(btrfs_free_space_cachep);
8048         if (btrfs_delalloc_work_cachep)
8049                 kmem_cache_destroy(btrfs_delalloc_work_cachep);
8050 }
8051
8052 int btrfs_init_cachep(void)
8053 {
8054         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
8055                         sizeof(struct btrfs_inode), 0,
8056                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, init_once);
8057         if (!btrfs_inode_cachep)
8058                 goto fail;
8059
8060         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
8061                         sizeof(struct btrfs_trans_handle), 0,
8062                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8063         if (!btrfs_trans_handle_cachep)
8064                 goto fail;
8065
8066         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
8067                         sizeof(struct btrfs_transaction), 0,
8068                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8069         if (!btrfs_transaction_cachep)
8070                 goto fail;
8071
8072         btrfs_path_cachep = kmem_cache_create("btrfs_path",
8073                         sizeof(struct btrfs_path), 0,
8074                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8075         if (!btrfs_path_cachep)
8076                 goto fail;
8077
8078         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
8079                         sizeof(struct btrfs_free_space), 0,
8080                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8081         if (!btrfs_free_space_cachep)
8082                 goto fail;
8083
8084         btrfs_delalloc_work_cachep = kmem_cache_create("btrfs_delalloc_work",
8085                         sizeof(struct btrfs_delalloc_work), 0,
8086                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
8087                         NULL);
8088         if (!btrfs_delalloc_work_cachep)
8089                 goto fail;
8090
8091         return 0;
8092 fail:
8093         btrfs_destroy_cachep();
8094         return -ENOMEM;
8095 }
8096
8097 static int btrfs_getattr(struct vfsmount *mnt,
8098                          struct dentry *dentry, struct kstat *stat)
8099 {
8100         u64 delalloc_bytes;
8101         struct inode *inode = dentry->d_inode;
8102         u32 blocksize = inode->i_sb->s_blocksize;
8103
8104         generic_fillattr(inode, stat);
8105         stat->dev = BTRFS_I(inode)->root->anon_dev;
8106         stat->blksize = PAGE_CACHE_SIZE;
8107
8108         spin_lock(&BTRFS_I(inode)->lock);
8109         delalloc_bytes = BTRFS_I(inode)->delalloc_bytes;
8110         spin_unlock(&BTRFS_I(inode)->lock);
8111         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
8112                         ALIGN(delalloc_bytes, blocksize)) >> 9;
8113         return 0;
8114 }
8115
8116 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
8117                            struct inode *new_dir, struct dentry *new_dentry)
8118 {
8119         struct btrfs_trans_handle *trans;
8120         struct btrfs_root *root = BTRFS_I(old_dir)->root;
8121         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
8122         struct inode *new_inode = new_dentry->d_inode;
8123         struct inode *old_inode = old_dentry->d_inode;
8124         struct timespec ctime = CURRENT_TIME;
8125         u64 index = 0;
8126         u64 root_objectid;
8127         int ret;
8128         u64 old_ino = btrfs_ino(old_inode);
8129
8130         if (btrfs_ino(new_dir) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
8131                 return -EPERM;
8132
8133         /* we only allow rename subvolume link between subvolumes */
8134         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
8135                 return -EXDEV;
8136
8137         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
8138             (new_inode && btrfs_ino(new_inode) == BTRFS_FIRST_FREE_OBJECTID))
8139                 return -ENOTEMPTY;
8140
8141         if (S_ISDIR(old_inode->i_mode) && new_inode &&
8142             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
8143                 return -ENOTEMPTY;
8144
8145
8146         /* check for collisions, even if the  name isn't there */
8147         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
8148                              new_dentry->d_name.name,
8149                              new_dentry->d_name.len);
8150
8151         if (ret) {
8152                 if (ret == -EEXIST) {
8153                         /* we shouldn't get
8154                          * eexist without a new_inode */
8155                         if (WARN_ON(!new_inode)) {
8156                                 return ret;
8157                         }
8158                 } else {
8159                         /* maybe -EOVERFLOW */
8160                         return ret;
8161                 }
8162         }
8163         ret = 0;
8164
8165         /*
8166          * we're using rename to replace one file with another.
8167          * and the replacement file is large.  Start IO on it now so
8168          * we don't add too much work to the end of the transaction
8169          */
8170         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size &&
8171             old_inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
8172                 filemap_flush(old_inode->i_mapping);
8173
8174         /* close the racy window with snapshot create/destroy ioctl */
8175         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8176                 down_read(&root->fs_info->subvol_sem);
8177         /*
8178          * We want to reserve the absolute worst case amount of items.  So if
8179          * both inodes are subvols and we need to unlink them then that would
8180          * require 4 item modifications, but if they are both normal inodes it
8181          * would require 5 item modifications, so we'll assume their normal
8182          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
8183          * should cover the worst case number of items we'll modify.
8184          */
8185         trans = btrfs_start_transaction(root, 11);
8186         if (IS_ERR(trans)) {
8187                 ret = PTR_ERR(trans);
8188                 goto out_notrans;
8189         }
8190
8191         if (dest != root)
8192                 btrfs_record_root_in_trans(trans, dest);
8193
8194         ret = btrfs_set_inode_index(new_dir, &index);
8195         if (ret)
8196                 goto out_fail;
8197
8198         BTRFS_I(old_inode)->dir_index = 0ULL;
8199         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8200                 /* force full log commit if subvolume involved. */
8201                 root->fs_info->last_trans_log_full_commit = trans->transid;
8202         } else {
8203                 ret = btrfs_insert_inode_ref(trans, dest,
8204                                              new_dentry->d_name.name,
8205                                              new_dentry->d_name.len,
8206                                              old_ino,
8207                                              btrfs_ino(new_dir), index);
8208                 if (ret)
8209                         goto out_fail;
8210                 /*
8211                  * this is an ugly little race, but the rename is required
8212                  * to make sure that if we crash, the inode is either at the
8213                  * old name or the new one.  pinning the log transaction lets
8214                  * us make sure we don't allow a log commit to come in after
8215                  * we unlink the name but before we add the new name back in.
8216                  */
8217                 btrfs_pin_log_trans(root);
8218         }
8219         /*
8220          * make sure the inode gets flushed if it is replacing
8221          * something.
8222          */
8223         if (new_inode && new_inode->i_size && S_ISREG(old_inode->i_mode))
8224                 btrfs_add_ordered_operation(trans, root, old_inode);
8225
8226         inode_inc_iversion(old_dir);
8227         inode_inc_iversion(new_dir);
8228         inode_inc_iversion(old_inode);
8229         old_dir->i_ctime = old_dir->i_mtime = ctime;
8230         new_dir->i_ctime = new_dir->i_mtime = ctime;
8231         old_inode->i_ctime = ctime;
8232
8233         if (old_dentry->d_parent != new_dentry->d_parent)
8234                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
8235
8236         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8237                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
8238                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
8239                                         old_dentry->d_name.name,
8240                                         old_dentry->d_name.len);
8241         } else {
8242                 ret = __btrfs_unlink_inode(trans, root, old_dir,
8243                                         old_dentry->d_inode,
8244                                         old_dentry->d_name.name,
8245                                         old_dentry->d_name.len);
8246                 if (!ret)
8247                         ret = btrfs_update_inode(trans, root, old_inode);
8248         }
8249         if (ret) {
8250                 btrfs_abort_transaction(trans, root, ret);
8251                 goto out_fail;
8252         }
8253
8254         if (new_inode) {
8255                 inode_inc_iversion(new_inode);
8256                 new_inode->i_ctime = CURRENT_TIME;
8257                 if (unlikely(btrfs_ino(new_inode) ==
8258                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
8259                         root_objectid = BTRFS_I(new_inode)->location.objectid;
8260                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
8261                                                 root_objectid,
8262                                                 new_dentry->d_name.name,
8263                                                 new_dentry->d_name.len);
8264                         BUG_ON(new_inode->i_nlink == 0);
8265                 } else {
8266                         ret = btrfs_unlink_inode(trans, dest, new_dir,
8267                                                  new_dentry->d_inode,
8268                                                  new_dentry->d_name.name,
8269                                                  new_dentry->d_name.len);
8270                 }
8271                 if (!ret && new_inode->i_nlink == 0)
8272                         ret = btrfs_orphan_add(trans, new_dentry->d_inode);
8273                 if (ret) {
8274                         btrfs_abort_transaction(trans, root, ret);
8275                         goto out_fail;
8276                 }
8277         }
8278
8279         ret = btrfs_add_link(trans, new_dir, old_inode,
8280                              new_dentry->d_name.name,
8281                              new_dentry->d_name.len, 0, index);
8282         if (ret) {
8283                 btrfs_abort_transaction(trans, root, ret);
8284                 goto out_fail;
8285         }
8286
8287         if (old_inode->i_nlink == 1)
8288                 BTRFS_I(old_inode)->dir_index = index;
8289
8290         if (old_ino != BTRFS_FIRST_FREE_OBJECTID) {
8291                 struct dentry *parent = new_dentry->d_parent;
8292                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
8293                 btrfs_end_log_trans(root);
8294         }
8295 out_fail:
8296         btrfs_end_transaction(trans, root);
8297 out_notrans:
8298         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8299                 up_read(&root->fs_info->subvol_sem);
8300
8301         return ret;
8302 }
8303
8304 static void btrfs_run_delalloc_work(struct btrfs_work *work)
8305 {
8306         struct btrfs_delalloc_work *delalloc_work;
8307         struct inode *inode;
8308
8309         delalloc_work = container_of(work, struct btrfs_delalloc_work,
8310                                      work);
8311         inode = delalloc_work->inode;
8312         if (delalloc_work->wait) {
8313                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
8314         } else {
8315                 filemap_flush(inode->i_mapping);
8316                 if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8317                              &BTRFS_I(inode)->runtime_flags))
8318                         filemap_flush(inode->i_mapping);
8319         }
8320
8321         if (delalloc_work->delay_iput)
8322                 btrfs_add_delayed_iput(inode);
8323         else
8324                 iput(inode);
8325         complete(&delalloc_work->completion);
8326 }
8327
8328 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
8329                                                     int wait, int delay_iput)
8330 {
8331         struct btrfs_delalloc_work *work;
8332
8333         work = kmem_cache_zalloc(btrfs_delalloc_work_cachep, GFP_NOFS);
8334         if (!work)
8335                 return NULL;
8336
8337         init_completion(&work->completion);
8338         INIT_LIST_HEAD(&work->list);
8339         work->inode = inode;
8340         work->wait = wait;
8341         work->delay_iput = delay_iput;
8342         work->work.func = btrfs_run_delalloc_work;
8343
8344         return work;
8345 }
8346
8347 void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
8348 {
8349         wait_for_completion(&work->completion);
8350         kmem_cache_free(btrfs_delalloc_work_cachep, work);
8351 }
8352
8353 /*
8354  * some fairly slow code that needs optimization. This walks the list
8355  * of all the inodes with pending delalloc and forces them to disk.
8356  */
8357 static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
8358 {
8359         struct btrfs_inode *binode;
8360         struct inode *inode;
8361         struct btrfs_delalloc_work *work, *next;
8362         struct list_head works;
8363         struct list_head splice;
8364         int ret = 0;
8365
8366         INIT_LIST_HEAD(&works);
8367         INIT_LIST_HEAD(&splice);
8368
8369         spin_lock(&root->delalloc_lock);
8370         list_splice_init(&root->delalloc_inodes, &splice);
8371         while (!list_empty(&splice)) {
8372                 binode = list_entry(splice.next, struct btrfs_inode,
8373                                     delalloc_inodes);
8374
8375                 list_move_tail(&binode->delalloc_inodes,
8376                                &root->delalloc_inodes);
8377                 inode = igrab(&binode->vfs_inode);
8378                 if (!inode) {
8379                         cond_resched_lock(&root->delalloc_lock);
8380                         continue;
8381                 }
8382                 spin_unlock(&root->delalloc_lock);
8383
8384                 work = btrfs_alloc_delalloc_work(inode, 0, delay_iput);
8385                 if (unlikely(!work)) {
8386                         if (delay_iput)
8387                                 btrfs_add_delayed_iput(inode);
8388                         else
8389                                 iput(inode);
8390                         ret = -ENOMEM;
8391                         goto out;
8392                 }
8393                 list_add_tail(&work->list, &works);
8394                 btrfs_queue_worker(&root->fs_info->flush_workers,
8395                                    &work->work);
8396
8397                 cond_resched();
8398                 spin_lock(&root->delalloc_lock);
8399         }
8400         spin_unlock(&root->delalloc_lock);
8401
8402         list_for_each_entry_safe(work, next, &works, list) {
8403                 list_del_init(&work->list);
8404                 btrfs_wait_and_free_delalloc_work(work);
8405         }
8406         return 0;
8407 out:
8408         list_for_each_entry_safe(work, next, &works, list) {
8409                 list_del_init(&work->list);
8410                 btrfs_wait_and_free_delalloc_work(work);
8411         }
8412
8413         if (!list_empty_careful(&splice)) {
8414                 spin_lock(&root->delalloc_lock);
8415                 list_splice_tail(&splice, &root->delalloc_inodes);
8416                 spin_unlock(&root->delalloc_lock);
8417         }
8418         return ret;
8419 }
8420
8421 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
8422 {
8423         int ret;
8424
8425         if (root->fs_info->sb->s_flags & MS_RDONLY)
8426                 return -EROFS;
8427
8428         ret = __start_delalloc_inodes(root, delay_iput);
8429         /*
8430          * the filemap_flush will queue IO into the worker threads, but
8431          * we have to make sure the IO is actually started and that
8432          * ordered extents get created before we return
8433          */
8434         atomic_inc(&root->fs_info->async_submit_draining);
8435         while (atomic_read(&root->fs_info->nr_async_submits) ||
8436               atomic_read(&root->fs_info->async_delalloc_pages)) {
8437                 wait_event(root->fs_info->async_submit_wait,
8438                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
8439                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
8440         }
8441         atomic_dec(&root->fs_info->async_submit_draining);
8442         return ret;
8443 }
8444
8445 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput)
8446 {
8447         struct btrfs_root *root;
8448         struct list_head splice;
8449         int ret;
8450
8451         if (fs_info->sb->s_flags & MS_RDONLY)
8452                 return -EROFS;
8453
8454         INIT_LIST_HEAD(&splice);
8455
8456         spin_lock(&fs_info->delalloc_root_lock);
8457         list_splice_init(&fs_info->delalloc_roots, &splice);
8458         while (!list_empty(&splice)) {
8459                 root = list_first_entry(&splice, struct btrfs_root,
8460                                         delalloc_root);
8461                 root = btrfs_grab_fs_root(root);
8462                 BUG_ON(!root);
8463                 list_move_tail(&root->delalloc_root,
8464                                &fs_info->delalloc_roots);
8465                 spin_unlock(&fs_info->delalloc_root_lock);
8466
8467                 ret = __start_delalloc_inodes(root, delay_iput);
8468                 btrfs_put_fs_root(root);
8469                 if (ret)
8470                         goto out;
8471
8472                 spin_lock(&fs_info->delalloc_root_lock);
8473         }
8474         spin_unlock(&fs_info->delalloc_root_lock);
8475
8476         atomic_inc(&fs_info->async_submit_draining);
8477         while (atomic_read(&fs_info->nr_async_submits) ||
8478               atomic_read(&fs_info->async_delalloc_pages)) {
8479                 wait_event(fs_info->async_submit_wait,
8480                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
8481                     atomic_read(&fs_info->async_delalloc_pages) == 0));
8482         }
8483         atomic_dec(&fs_info->async_submit_draining);
8484         return 0;
8485 out:
8486         if (!list_empty_careful(&splice)) {
8487                 spin_lock(&fs_info->delalloc_root_lock);
8488                 list_splice_tail(&splice, &fs_info->delalloc_roots);
8489                 spin_unlock(&fs_info->delalloc_root_lock);
8490         }
8491         return ret;
8492 }
8493
8494 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
8495                          const char *symname)
8496 {
8497         struct btrfs_trans_handle *trans;
8498         struct btrfs_root *root = BTRFS_I(dir)->root;
8499         struct btrfs_path *path;
8500         struct btrfs_key key;
8501         struct inode *inode = NULL;
8502         int err;
8503         int drop_inode = 0;
8504         u64 objectid;
8505         u64 index = 0;
8506         int name_len;
8507         int datasize;
8508         unsigned long ptr;
8509         struct btrfs_file_extent_item *ei;
8510         struct extent_buffer *leaf;
8511
8512         name_len = strlen(symname);
8513         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
8514                 return -ENAMETOOLONG;
8515
8516         /*
8517          * 2 items for inode item and ref
8518          * 2 items for dir items
8519          * 1 item for xattr if selinux is on
8520          */
8521         trans = btrfs_start_transaction(root, 5);
8522         if (IS_ERR(trans))
8523                 return PTR_ERR(trans);
8524
8525         err = btrfs_find_free_ino(root, &objectid);
8526         if (err)
8527                 goto out_unlock;
8528
8529         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
8530                                 dentry->d_name.len, btrfs_ino(dir), objectid,
8531                                 S_IFLNK|S_IRWXUGO, &index);
8532         if (IS_ERR(inode)) {
8533                 err = PTR_ERR(inode);
8534                 goto out_unlock;
8535         }
8536
8537         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
8538         if (err) {
8539                 drop_inode = 1;
8540                 goto out_unlock;
8541         }
8542
8543         /*
8544         * If the active LSM wants to access the inode during
8545         * d_instantiate it needs these. Smack checks to see
8546         * if the filesystem supports xattrs by looking at the
8547         * ops vector.
8548         */
8549         inode->i_fop = &btrfs_file_operations;
8550         inode->i_op = &btrfs_file_inode_operations;
8551
8552         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
8553         if (err)
8554                 drop_inode = 1;
8555         else {
8556                 inode->i_mapping->a_ops = &btrfs_aops;
8557                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
8558                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
8559         }
8560         if (drop_inode)
8561                 goto out_unlock;
8562
8563         path = btrfs_alloc_path();
8564         if (!path) {
8565                 err = -ENOMEM;
8566                 drop_inode = 1;
8567                 goto out_unlock;
8568         }
8569         key.objectid = btrfs_ino(inode);
8570         key.offset = 0;
8571         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
8572         datasize = btrfs_file_extent_calc_inline_size(name_len);
8573         err = btrfs_insert_empty_item(trans, root, path, &key,
8574                                       datasize);
8575         if (err) {
8576                 drop_inode = 1;
8577                 btrfs_free_path(path);
8578                 goto out_unlock;
8579         }
8580         leaf = path->nodes[0];
8581         ei = btrfs_item_ptr(leaf, path->slots[0],
8582                             struct btrfs_file_extent_item);
8583         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
8584         btrfs_set_file_extent_type(leaf, ei,
8585                                    BTRFS_FILE_EXTENT_INLINE);
8586         btrfs_set_file_extent_encryption(leaf, ei, 0);
8587         btrfs_set_file_extent_compression(leaf, ei, 0);
8588         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
8589         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
8590
8591         ptr = btrfs_file_extent_inline_start(ei);
8592         write_extent_buffer(leaf, symname, ptr, name_len);
8593         btrfs_mark_buffer_dirty(leaf);
8594         btrfs_free_path(path);
8595
8596         inode->i_op = &btrfs_symlink_inode_operations;
8597         inode->i_mapping->a_ops = &btrfs_symlink_aops;
8598         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
8599         inode_set_bytes(inode, name_len);
8600         btrfs_i_size_write(inode, name_len);
8601         err = btrfs_update_inode(trans, root, inode);
8602         if (err)
8603                 drop_inode = 1;
8604
8605 out_unlock:
8606         if (!err)
8607                 d_instantiate(dentry, inode);
8608         btrfs_end_transaction(trans, root);
8609         if (drop_inode) {
8610                 inode_dec_link_count(inode);
8611                 iput(inode);
8612         }
8613         btrfs_btree_balance_dirty(root);
8614         return err;
8615 }
8616
8617 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
8618                                        u64 start, u64 num_bytes, u64 min_size,
8619                                        loff_t actual_len, u64 *alloc_hint,
8620                                        struct btrfs_trans_handle *trans)
8621 {
8622         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
8623         struct extent_map *em;
8624         struct btrfs_root *root = BTRFS_I(inode)->root;
8625         struct btrfs_key ins;
8626         u64 cur_offset = start;
8627         u64 i_size;
8628         u64 cur_bytes;
8629         int ret = 0;
8630         bool own_trans = true;
8631
8632         if (trans)
8633                 own_trans = false;
8634         while (num_bytes > 0) {
8635                 if (own_trans) {
8636                         trans = btrfs_start_transaction(root, 3);
8637                         if (IS_ERR(trans)) {
8638                                 ret = PTR_ERR(trans);
8639                                 break;
8640                         }
8641                 }
8642
8643                 cur_bytes = min(num_bytes, 256ULL * 1024 * 1024);
8644                 cur_bytes = max(cur_bytes, min_size);
8645                 ret = btrfs_reserve_extent(root, cur_bytes, min_size, 0,
8646                                            *alloc_hint, &ins, 1);
8647                 if (ret) {
8648                         if (own_trans)
8649                                 btrfs_end_transaction(trans, root);
8650                         break;
8651                 }
8652
8653                 ret = insert_reserved_file_extent(trans, inode,
8654                                                   cur_offset, ins.objectid,
8655                                                   ins.offset, ins.offset,
8656                                                   ins.offset, 0, 0, 0,
8657                                                   BTRFS_FILE_EXTENT_PREALLOC);
8658                 if (ret) {
8659                         btrfs_free_reserved_extent(root, ins.objectid,
8660                                                    ins.offset);
8661                         btrfs_abort_transaction(trans, root, ret);
8662                         if (own_trans)
8663                                 btrfs_end_transaction(trans, root);
8664                         break;
8665                 }
8666                 btrfs_drop_extent_cache(inode, cur_offset,
8667                                         cur_offset + ins.offset -1, 0);
8668
8669                 em = alloc_extent_map();
8670                 if (!em) {
8671                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
8672                                 &BTRFS_I(inode)->runtime_flags);
8673                         goto next;
8674                 }
8675
8676                 em->start = cur_offset;
8677                 em->orig_start = cur_offset;
8678                 em->len = ins.offset;
8679                 em->block_start = ins.objectid;
8680                 em->block_len = ins.offset;
8681                 em->orig_block_len = ins.offset;
8682                 em->ram_bytes = ins.offset;
8683                 em->bdev = root->fs_info->fs_devices->latest_bdev;
8684                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
8685                 em->generation = trans->transid;
8686
8687                 while (1) {
8688                         write_lock(&em_tree->lock);
8689                         ret = add_extent_mapping(em_tree, em, 1);
8690                         write_unlock(&em_tree->lock);
8691                         if (ret != -EEXIST)
8692                                 break;
8693                         btrfs_drop_extent_cache(inode, cur_offset,
8694                                                 cur_offset + ins.offset - 1,
8695                                                 0);
8696                 }
8697                 free_extent_map(em);
8698 next:
8699                 num_bytes -= ins.offset;
8700                 cur_offset += ins.offset;
8701                 *alloc_hint = ins.objectid + ins.offset;
8702
8703                 inode_inc_iversion(inode);
8704                 inode->i_ctime = CURRENT_TIME;
8705                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
8706                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
8707                     (actual_len > inode->i_size) &&
8708                     (cur_offset > inode->i_size)) {
8709                         if (cur_offset > actual_len)
8710                                 i_size = actual_len;
8711                         else
8712                                 i_size = cur_offset;
8713                         i_size_write(inode, i_size);
8714                         btrfs_ordered_update_i_size(inode, i_size, NULL);
8715                 }
8716
8717                 ret = btrfs_update_inode(trans, root, inode);
8718
8719                 if (ret) {
8720                         btrfs_abort_transaction(trans, root, ret);
8721                         if (own_trans)
8722                                 btrfs_end_transaction(trans, root);
8723                         break;
8724                 }
8725
8726                 if (own_trans)
8727                         btrfs_end_transaction(trans, root);
8728         }
8729         return ret;
8730 }
8731
8732 int btrfs_prealloc_file_range(struct inode *inode, int mode,
8733                               u64 start, u64 num_bytes, u64 min_size,
8734                               loff_t actual_len, u64 *alloc_hint)
8735 {
8736         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
8737                                            min_size, actual_len, alloc_hint,
8738                                            NULL);
8739 }
8740
8741 int btrfs_prealloc_file_range_trans(struct inode *inode,
8742                                     struct btrfs_trans_handle *trans, int mode,
8743                                     u64 start, u64 num_bytes, u64 min_size,
8744                                     loff_t actual_len, u64 *alloc_hint)
8745 {
8746         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
8747                                            min_size, actual_len, alloc_hint, trans);
8748 }
8749
8750 static int btrfs_set_page_dirty(struct page *page)
8751 {
8752         return __set_page_dirty_nobuffers(page);
8753 }
8754
8755 static int btrfs_permission(struct inode *inode, int mask)
8756 {
8757         struct btrfs_root *root = BTRFS_I(inode)->root;
8758         umode_t mode = inode->i_mode;
8759
8760         if (mask & MAY_WRITE &&
8761             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
8762                 if (btrfs_root_readonly(root))
8763                         return -EROFS;
8764                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
8765                         return -EACCES;
8766         }
8767         return generic_permission(inode, mask);
8768 }
8769
8770 static const struct inode_operations btrfs_dir_inode_operations = {
8771         .getattr        = btrfs_getattr,
8772         .lookup         = btrfs_lookup,
8773         .create         = btrfs_create,
8774         .unlink         = btrfs_unlink,
8775         .link           = btrfs_link,
8776         .mkdir          = btrfs_mkdir,
8777         .rmdir          = btrfs_rmdir,
8778         .rename         = btrfs_rename,
8779         .symlink        = btrfs_symlink,
8780         .setattr        = btrfs_setattr,
8781         .mknod          = btrfs_mknod,
8782         .setxattr       = btrfs_setxattr,
8783         .getxattr       = btrfs_getxattr,
8784         .listxattr      = btrfs_listxattr,
8785         .removexattr    = btrfs_removexattr,
8786         .permission     = btrfs_permission,
8787         .get_acl        = btrfs_get_acl,
8788         .update_time    = btrfs_update_time,
8789 };
8790 static const struct inode_operations btrfs_dir_ro_inode_operations = {
8791         .lookup         = btrfs_lookup,
8792         .permission     = btrfs_permission,
8793         .get_acl        = btrfs_get_acl,
8794         .update_time    = btrfs_update_time,
8795 };
8796
8797 static const struct file_operations btrfs_dir_file_operations = {
8798         .llseek         = generic_file_llseek,
8799         .read           = generic_read_dir,
8800         .iterate        = btrfs_real_readdir,
8801         .unlocked_ioctl = btrfs_ioctl,
8802 #ifdef CONFIG_COMPAT
8803         .compat_ioctl   = btrfs_ioctl,
8804 #endif
8805         .release        = btrfs_release_file,
8806         .fsync          = btrfs_sync_file,
8807 };
8808
8809 static struct extent_io_ops btrfs_extent_io_ops = {
8810         .fill_delalloc = run_delalloc_range,
8811         .submit_bio_hook = btrfs_submit_bio_hook,
8812         .merge_bio_hook = btrfs_merge_bio_hook,
8813         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
8814         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
8815         .writepage_start_hook = btrfs_writepage_start_hook,
8816         .set_bit_hook = btrfs_set_bit_hook,
8817         .clear_bit_hook = btrfs_clear_bit_hook,
8818         .merge_extent_hook = btrfs_merge_extent_hook,
8819         .split_extent_hook = btrfs_split_extent_hook,
8820 };
8821
8822 /*
8823  * btrfs doesn't support the bmap operation because swapfiles
8824  * use bmap to make a mapping of extents in the file.  They assume
8825  * these extents won't change over the life of the file and they
8826  * use the bmap result to do IO directly to the drive.
8827  *
8828  * the btrfs bmap call would return logical addresses that aren't
8829  * suitable for IO and they also will change frequently as COW
8830  * operations happen.  So, swapfile + btrfs == corruption.
8831  *
8832  * For now we're avoiding this by dropping bmap.
8833  */
8834 static const struct address_space_operations btrfs_aops = {
8835         .readpage       = btrfs_readpage,
8836         .writepage      = btrfs_writepage,
8837         .writepages     = btrfs_writepages,
8838         .readpages      = btrfs_readpages,
8839         .direct_IO      = btrfs_direct_IO,
8840         .invalidatepage = btrfs_invalidatepage,
8841         .releasepage    = btrfs_releasepage,
8842         .set_page_dirty = btrfs_set_page_dirty,
8843         .error_remove_page = generic_error_remove_page,
8844 };
8845
8846 static const struct address_space_operations btrfs_symlink_aops = {
8847         .readpage       = btrfs_readpage,
8848         .writepage      = btrfs_writepage,
8849         .invalidatepage = btrfs_invalidatepage,
8850         .releasepage    = btrfs_releasepage,
8851 };
8852
8853 static const struct inode_operations btrfs_file_inode_operations = {
8854         .getattr        = btrfs_getattr,
8855         .setattr        = btrfs_setattr,
8856         .setxattr       = btrfs_setxattr,
8857         .getxattr       = btrfs_getxattr,
8858         .listxattr      = btrfs_listxattr,
8859         .removexattr    = btrfs_removexattr,
8860         .permission     = btrfs_permission,
8861         .fiemap         = btrfs_fiemap,
8862         .get_acl        = btrfs_get_acl,
8863         .update_time    = btrfs_update_time,
8864 };
8865 static const struct inode_operations btrfs_special_inode_operations = {
8866         .getattr        = btrfs_getattr,
8867         .setattr        = btrfs_setattr,
8868         .permission     = btrfs_permission,
8869         .setxattr       = btrfs_setxattr,
8870         .getxattr       = btrfs_getxattr,
8871         .listxattr      = btrfs_listxattr,
8872         .removexattr    = btrfs_removexattr,
8873         .get_acl        = btrfs_get_acl,
8874         .update_time    = btrfs_update_time,
8875 };
8876 static const struct inode_operations btrfs_symlink_inode_operations = {
8877         .readlink       = generic_readlink,
8878         .follow_link    = page_follow_link_light,
8879         .put_link       = page_put_link,
8880         .getattr        = btrfs_getattr,
8881         .setattr        = btrfs_setattr,
8882         .permission     = btrfs_permission,
8883         .setxattr       = btrfs_setxattr,
8884         .getxattr       = btrfs_getxattr,
8885         .listxattr      = btrfs_listxattr,
8886         .removexattr    = btrfs_removexattr,
8887         .get_acl        = btrfs_get_acl,
8888         .update_time    = btrfs_update_time,
8889 };
8890
8891 const struct dentry_operations btrfs_dentry_operations = {
8892         .d_delete       = btrfs_dentry_delete,
8893         .d_release      = btrfs_dentry_release,
8894 };