fs/btrfs/file.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/fs.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/highmem.h>
  22 #include <linux/time.h>
  23 #include <linux/init.h>
  24 #include <linux/string.h>
  25 #include <linux/backing-dev.h>
  26 #include <linux/mpage.h>
  27 #include <linux/swap.h>
  28 #include <linux/writeback.h>
  29 #include <linux/statfs.h>
  30 #include <linux/compat.h>
  31 #include <linux/slab.h>
  32 #include "ctree.h"
  33 #include "disk-io.h"
  34 #include "transaction.h"
  35 #include "btrfs_inode.h"
  36 #include "ioctl.h"
  37 #include "print-tree.h"
  38 #include "tree-log.h"
  39 #include "locking.h"
  40 #include "compat.h"
  41
  42
  43 /* simple helper to fault in pages and copy.  This should go away
  44  * and be replaced with calls into generic code.
  45  */
  46 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
  47                                          int write_bytes,
  48                                          struct page **prepared_pages,
  49                                          struct iov_iter *i)
  50 {
  51         size_t copied = 0;
  52         int pg = 0;
  53         int offset = pos & (PAGE_CACHE_SIZE - 1);
  54         int total_copied = 0;
  55
  56         while (write_bytes > 0) {
  57                 size_t count = min_t(size_t,
  58                                      PAGE_CACHE_SIZE - offset, write_bytes);
  59                 struct page *page = prepared_pages[pg];
  60                 /*
  61                  * Copy data from userspace to the current page
  62                  *
  63                  * Disable pagefault to avoid recursive lock since
  64                  * the pages are already locked
  65                  */
  66                 pagefault_disable();
  67                 copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
  68                 pagefault_enable();
  69
  70                 /* Flush processor's dcache for this page */
  71                 flush_dcache_page(page);
  72
  73                 /*
  74                  * if we get a partial write, we can end up with
  75                  * partially up to date pages.  These add
  76                  * a lot of complexity, so make sure they don't
  77                  * happen by forcing this copy to be retried.
  78                  *
  79                  * The rest of the btrfs_file_write code will fall
  80                  * back to page at a time copies after we return 0.
  81                  */
  82                 if (!PageUptodate(page) && copied < count)
  83                         copied = 0;
  84
  85                 iov_iter_advance(i, copied);
  86                 write_bytes -= copied;
  87                 total_copied += copied;
  88
  89                 /* Return to btrfs_file_aio_write to fault page */
  90                 if (unlikely(copied == 0)) {
  91                         break;
  92                 }
  93
  94                 if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
  95                         offset += copied;
  96                 } else {
  97                         pg++;
  98                         offset = 0;
  99                 }
 100         }
 101         return total_copied;
 102 }
 103
 104 /*
 105  * unlocks pages after btrfs_file_write is done with them
 106  */
 107 static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages)
 108 {
 109         size_t i;
 110         for (i = 0; i < num_pages; i++) {
 111                 if (!pages[i])
 112                         break;
 113                 /* page checked is some magic around finding pages that
 114                  * have been modified without going through btrfs_set_page_dirty
 115                  * clear it here
 116                  */
 117                 ClearPageChecked(pages[i]);
 118                 unlock_page(pages[i]);
 119                 mark_page_accessed(pages[i]);
 120                 page_cache_release(pages[i]);
 121         }
 122 }
 123
 124 /*
 125  * after copy_from_user, pages need to be dirtied and we need to make
 126  * sure holes are created between the current EOF and the start of
 127  * any next extents (if required).
 128  *
 129  * this also makes the decision about creating an inline extent vs
 130  * doing real data extents, marking pages dirty and delalloc as required.
 131  */
 132 static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
 133                                    struct btrfs_root *root,
 134                                    struct file *file,
 135                                    struct page **pages,
 136                                    size_t num_pages,
 137                                    loff_t pos,
 138                                    size_t write_bytes)
 139 {
 140         int err = 0;
 141         int i;
 142         struct inode *inode = fdentry(file)->d_inode;
 143         u64 num_bytes;
 144         u64 start_pos;
 145         u64 end_of_last_block;
 146         u64 end_pos = pos + write_bytes;
 147         loff_t isize = i_size_read(inode);
 148
 149         start_pos = pos & ~((u64)root->sectorsize - 1);
 150         num_bytes = (write_bytes + pos - start_pos +
 151                     root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
 152
 153         end_of_last_block = start_pos + num_bytes - 1;
 154         err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
 155                                         NULL);
 156         BUG_ON(err);
 157
 158         for (i = 0; i < num_pages; i++) {
 159                 struct page *p = pages[i];
 160                 SetPageUptodate(p);
 161                 ClearPageChecked(p);
 162                 set_page_dirty(p);
 163         }
 164         if (end_pos > isize) {
 165                 i_size_write(inode, end_pos);
 166                 /* we've only changed i_size in ram, and we haven't updated
 167                  * the disk i_size.  There is no need to log the inode
 168                  * at this time.
 169                  */
 170         }
 171         return 0;
 172 }
 173
 174 /*
 175  * this drops all the extents in the cache that intersect the range
 176  * [start, end].  Existing extents are split as required.
 177  */
 178 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
 179                             int skip_pinned)
 180 {
 181         struct extent_map *em;
 182         struct extent_map *split = NULL;
 183         struct extent_map *split2 = NULL;
 184         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 185         u64 len = end - start + 1;
 186         int ret;
 187         int testend = 1;
 188         unsigned long flags;
 189         int compressed = 0;
 190
 191         WARN_ON(end < start);
 192         if (end == (u64)-1) {
 193                 len = (u64)-1;
 194                 testend = 0;
 195         }
 196         while (1) {
 197                 if (!split)
 198                         split = alloc_extent_map(GFP_NOFS);
 199                 if (!split2)
 200                         split2 = alloc_extent_map(GFP_NOFS);
 201                 BUG_ON(!split || !split2);
 202
 203                 write_lock(&em_tree->lock);
 204                 em = lookup_extent_mapping(em_tree, start, len);
 205                 if (!em) {
 206                         write_unlock(&em_tree->lock);
 207                         break;
 208                 }
 209                 flags = em->flags;
 210                 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
 211                         if (testend && em->start + em->len >= start + len) {
 212                                 free_extent_map(em);
 213                                 write_unlock(&em_tree->lock);
 214                                 break;
 215                         }
 216                         start = em->start + em->len;
 217                         if (testend)
 218                                 len = start + len - (em->start + em->len);
 219                         free_extent_map(em);
 220                         write_unlock(&em_tree->lock);
 221                         continue;
 222                 }
 223                 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 224                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
 225                 remove_extent_mapping(em_tree, em);
 226
 227                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 228                     em->start < start) {
 229                         split->start = em->start;
 230                         split->len = start - em->start;
 231                         split->orig_start = em->orig_start;
 232                         split->block_start = em->block_start;
 233
 234                         if (compressed)
 235                                 split->block_len = em->block_len;
 236                         else
 237                                 split->block_len = split->len;
 238
 239                         split->bdev = em->bdev;
 240                         split->flags = flags;
 241                         split->compress_type = em->compress_type;
 242                         ret = add_extent_mapping(em_tree, split);
 243                         BUG_ON(ret);
 244                         free_extent_map(split);
 245                         split = split2;
 246                         split2 = NULL;
 247                 }
 248                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 249                     testend && em->start + em->len > start + len) {
 250                         u64 diff = start + len - em->start;
 251
 252                         split->start = start + len;
 253                         split->len = em->start + em->len - (start + len);
 254                         split->bdev = em->bdev;
 255                         split->flags = flags;
 256                         split->compress_type = em->compress_type;
 257
 258                         if (compressed) {
 259                                 split->block_len = em->block_len;
 260                                 split->block_start = em->block_start;
 261                                 split->orig_start = em->orig_start;
 262                         } else {
 263                                 split->block_len = split->len;
 264                                 split->block_start = em->block_start + diff;
 265                                 split->orig_start = split->start;
 266                         }
 267
 268                         ret = add_extent_mapping(em_tree, split);
 269                         BUG_ON(ret);
 270                         free_extent_map(split);
 271                         split = NULL;
 272                 }
 273                 write_unlock(&em_tree->lock);
 274
 275                 /* once for us */
 276                 free_extent_map(em);
 277                 /* once for the tree*/
 278                 free_extent_map(em);
 279         }
 280         if (split)
 281                 free_extent_map(split);
 282         if (split2)
 283                 free_extent_map(split2);
 284         return 0;
 285 }
 286
 287 /*
 288  * this is very complex, but the basic idea is to drop all extents
 289  * in the range start - end.  hint_block is filled in with a block number
 290  * that would be a good hint to the block allocator for this file.
 291  *
 292  * If an extent intersects the range but is not entirely inside the range
 293  * it is either truncated or split.  Anything entirely inside the range
 294  * is deleted from the tree.
 295  */
 296 int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
 297                        u64 start, u64 end, u64 *hint_byte, int drop_cache)
 298 {
 299         struct btrfs_root *root = BTRFS_I(inode)->root;
 300         struct extent_buffer *leaf;
 301         struct btrfs_file_extent_item *fi;
 302         struct btrfs_path *path;
 303         struct btrfs_key key;
 304         struct btrfs_key new_key;
 305         u64 search_start = start;
 306         u64 disk_bytenr = 0;
 307         u64 num_bytes = 0;
 308         u64 extent_offset = 0;
 309         u64 extent_end = 0;
 310         int del_nr = 0;
 311         int del_slot = 0;
 312         int extent_type;
 313         int recow;
 314         int ret;
 315
 316         if (drop_cache)
 317                 btrfs_drop_extent_cache(inode, start, end - 1, 0);
 318
 319         path = btrfs_alloc_path();
 320         if (!path)
 321                 return -ENOMEM;
 322
 323         while (1) {
 324                 recow = 0;
 325                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
 326                                                search_start, -1);
 327                 if (ret < 0)
 328                         break;
 329                 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
 330                         leaf = path->nodes[0];
 331                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
 332                         if (key.objectid == inode->i_ino &&
 333                             key.type == BTRFS_EXTENT_DATA_KEY)
 334                                 path->slots[0]--;
 335                 }
 336                 ret = 0;
 337 next_slot:
 338                 leaf = path->nodes[0];
 339                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 340                         BUG_ON(del_nr > 0);
 341                         ret = btrfs_next_leaf(root, path);
 342                         if (ret < 0)
 343                                 break;
 344                         if (ret > 0) {
 345                                 ret = 0;
 346                                 break;
 347                         }
 348                         leaf = path->nodes[0];
 349                         recow = 1;
 350                 }
 351
 352                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 353                 if (key.objectid > inode->i_ino ||
 354                     key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
 355                         break;
 356
 357                 fi = btrfs_item_ptr(leaf, path->slots[0],
 358                                     struct btrfs_file_extent_item);
 359                 extent_type = btrfs_file_extent_type(leaf, fi);
 360
 361                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
 362                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
 363                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
 364                         num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
 365                         extent_offset = btrfs_file_extent_offset(leaf, fi);
 366                         extent_end = key.offset +
 367                                 btrfs_file_extent_num_bytes(leaf, fi);
 368                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 369                         extent_end = key.offset +
 370                                 btrfs_file_extent_inline_len(leaf, fi);
 371                 } else {
 372                         WARN_ON(1);
 373                         extent_end = search_start;
 374                 }
 375
 376                 if (extent_end <= search_start) {
 377                         path->slots[0]++;
 378                         goto next_slot;
 379                 }
 380
 381                 search_start = max(key.offset, start);
 382                 if (recow) {
 383                         btrfs_release_path(root, path);
 384                         continue;
 385                 }
 386
 387                 /*
 388                  *     | - range to drop - |
 389                  *  | -------- extent -------- |
 390                  */
 391                 if (start > key.offset && end < extent_end) {
 392                         BUG_ON(del_nr > 0);
 393                         BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
 394
 395                         memcpy(&new_key, &key, sizeof(new_key));
 396                         new_key.offset = start;
 397                         ret = btrfs_duplicate_item(trans, root, path,
 398                                                    &new_key);
 399                         if (ret == -EAGAIN) {
 400                                 btrfs_release_path(root, path);
 401                                 continue;
 402                         }
 403                         if (ret < 0)
 404                                 break;
 405
 406                         leaf = path->nodes[0];
 407                         fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
 408                                             struct btrfs_file_extent_item);
 409                         btrfs_set_file_extent_num_bytes(leaf, fi,
 410                                                         start - key.offset);
 411
 412                         fi = btrfs_item_ptr(leaf, path->slots[0],
 413                                             struct btrfs_file_extent_item);
 414
 415                         extent_offset += start - key.offset;
 416                         btrfs_set_file_extent_offset(leaf, fi, extent_offset);
 417                         btrfs_set_file_extent_num_bytes(leaf, fi,
 418                                                         extent_end - start);
 419                         btrfs_mark_buffer_dirty(leaf);
 420
 421                         if (disk_bytenr > 0) {
 422                                 ret = btrfs_inc_extent_ref(trans, root,
 423                                                 disk_bytenr, num_bytes, 0,
 424                                                 root->root_key.objectid,
 425                                                 new_key.objectid,
 426                                                 start - extent_offset);
 427                                 BUG_ON(ret);
 428                                 *hint_byte = disk_bytenr;
 429                         }
 430                         key.offset = start;
 431                 }
 432                 /*
 433                  *  | ---- range to drop ----- |
 434                  *      | -------- extent -------- |
 435                  */
 436                 if (start <= key.offset && end < extent_end) {
 437                         BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
 438
 439                         memcpy(&new_key, &key, sizeof(new_key));
 440                         new_key.offset = end;
 441                         btrfs_set_item_key_safe(trans, root, path, &new_key);
 442
 443                         extent_offset += end - key.offset;
 444                         btrfs_set_file_extent_offset(leaf, fi, extent_offset);
 445                         btrfs_set_file_extent_num_bytes(leaf, fi,
 446                                                         extent_end - end);
 447                         btrfs_mark_buffer_dirty(leaf);
 448                         if (disk_bytenr > 0) {
 449                                 inode_sub_bytes(inode, end - key.offset);
 450                                 *hint_byte = disk_bytenr;
 451                         }
 452                         break;
 453                 }
 454
 455                 search_start = extent_end;
 456                 /*
 457                  *       | ---- range to drop ----- |
 458                  *  | -------- extent -------- |
 459                  */
 460                 if (start > key.offset && end >= extent_end) {
 461                         BUG_ON(del_nr > 0);
 462                         BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
 463
 464                         btrfs_set_file_extent_num_bytes(leaf, fi,
 465                                                         start - key.offset);
 466                         btrfs_mark_buffer_dirty(leaf);
 467                         if (disk_bytenr > 0) {
 468                                 inode_sub_bytes(inode, extent_end - start);
 469                                 *hint_byte = disk_bytenr;
 470                         }
 471                         if (end == extent_end)
 472                                 break;
 473
 474                         path->slots[0]++;
 475                         goto next_slot;
 476                 }
 477
 478                 /*
 479                  *  | ---- range to drop ----- |
 480                  *    | ------ extent ------ |
 481                  */
 482                 if (start <= key.offset && end >= extent_end) {
 483                         if (del_nr == 0) {
 484                                 del_slot = path->slots[0];
 485                                 del_nr = 1;
 486                         } else {
 487                                 BUG_ON(del_slot + del_nr != path->slots[0]);
 488                                 del_nr++;
 489                         }
 490
 491                         if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 492                                 inode_sub_bytes(inode,
 493                                                 extent_end - key.offset);
 494                                 extent_end = ALIGN(extent_end,
 495                                                    root->sectorsize);
 496                         } else if (disk_bytenr > 0) {
 497                                 ret = btrfs_free_extent(trans, root,
 498                                                 disk_bytenr, num_bytes, 0,
 499                                                 root->root_key.objectid,
 500                                                 key.objectid, key.offset -
 501                                                 extent_offset);
 502                                 BUG_ON(ret);
 503                                 inode_sub_bytes(inode,
 504                                                 extent_end - key.offset);
 505                                 *hint_byte = disk_bytenr;
 506                         }
 507
 508                         if (end == extent_end)
 509                                 break;
 510
 511                         if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
 512                                 path->slots[0]++;
 513                                 goto next_slot;
 514                         }
 515
 516                         ret = btrfs_del_items(trans, root, path, del_slot,
 517                                               del_nr);
 518                         BUG_ON(ret);
 519
 520                         del_nr = 0;
 521                         del_slot = 0;
 522
 523                         btrfs_release_path(root, path);
 524                         continue;
 525                 }
 526
 527                 BUG_ON(1);
 528         }
 529
 530         if (del_nr > 0) {
 531                 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
 532                 BUG_ON(ret);
 533         }
 534
 535         btrfs_free_path(path);
 536         return ret;
 537 }
 538
 539 static int extent_mergeable(struct extent_buffer *leaf, int slot,
 540                             u64 objectid, u64 bytenr, u64 orig_offset,
 541                             u64 *start, u64 *end)
 542 {
 543         struct btrfs_file_extent_item *fi;
 544         struct btrfs_key key;
 545         u64 extent_end;
 546
 547         if (slot < 0 || slot >= btrfs_header_nritems(leaf))
 548                 return 0;
 549
 550         btrfs_item_key_to_cpu(leaf, &key, slot);
 551         if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
 552                 return 0;
 553
 554         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
 555         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
 556             btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
 557             btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
 558             btrfs_file_extent_compression(leaf, fi) ||
 559             btrfs_file_extent_encryption(leaf, fi) ||
 560             btrfs_file_extent_other_encoding(leaf, fi))
 561                 return 0;
 562
 563         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
 564         if ((*start && *start != key.offset) || (*end && *end != extent_end))
 565                 return 0;
 566
 567         *start = key.offset;
 568         *end = extent_end;
 569         return 1;
 570 }
 571
 572 /*
 573  * Mark extent in the range start - end as written.
 574  *
 575  * This changes extent type from 'pre-allocated' to 'regular'. If only
 576  * part of extent is marked as written, the extent will be split into
 577  * two or three.
 578  */
 579 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
 580                               struct inode *inode, u64 start, u64 end)
 581 {
 582         struct btrfs_root *root = BTRFS_I(inode)->root;
 583         struct extent_buffer *leaf;
 584         struct btrfs_path *path;
 585         struct btrfs_file_extent_item *fi;
 586         struct btrfs_key key;
 587         struct btrfs_key new_key;
 588         u64 bytenr;
 589         u64 num_bytes;
 590         u64 extent_end;
 591         u64 orig_offset;
 592         u64 other_start;
 593         u64 other_end;
 594         u64 split;
 595         int del_nr = 0;
 596         int del_slot = 0;
 597         int recow;
 598         int ret;
 599
 600         btrfs_drop_extent_cache(inode, start, end - 1, 0);
 601
 602         path = btrfs_alloc_path();
 603         BUG_ON(!path);
 604 again:
 605         recow = 0;
 606         split = start;
 607         key.objectid = inode->i_ino;
 608         key.type = BTRFS_EXTENT_DATA_KEY;
 609         key.offset = split;
 610
 611         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 612         if (ret > 0 && path->slots[0] > 0)
 613                 path->slots[0]--;
 614
 615         leaf = path->nodes[0];
 616         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 617         BUG_ON(key.objectid != inode->i_ino ||
 618                key.type != BTRFS_EXTENT_DATA_KEY);
 619         fi = btrfs_item_ptr(leaf, path->slots[0],
 620                             struct btrfs_file_extent_item);
 621         BUG_ON(btrfs_file_extent_type(leaf, fi) !=
 622                BTRFS_FILE_EXTENT_PREALLOC);
 623         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
 624         BUG_ON(key.offset > start || extent_end < end);
 625
 626         bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
 627         num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
 628         orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
 629         memcpy(&new_key, &key, sizeof(new_key));
 630
 631         if (start == key.offset && end < extent_end) {
 632                 other_start = 0;
 633                 other_end = start;
 634                 if (extent_mergeable(leaf, path->slots[0] - 1,
 635                                      inode->i_ino, bytenr, orig_offset,
 636                                      &other_start, &other_end)) {
 637                         new_key.offset = end;
 638                         btrfs_set_item_key_safe(trans, root, path, &new_key);
 639                         fi = btrfs_item_ptr(leaf, path->slots[0],
 640                                             struct btrfs_file_extent_item);
 641                         btrfs_set_file_extent_num_bytes(leaf, fi,
 642                                                         extent_end - end);
 643                         btrfs_set_file_extent_offset(leaf, fi,
 644                                                      end - orig_offset);
 645                         fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
 646                                             struct btrfs_file_extent_item);
 647                         btrfs_set_file_extent_num_bytes(leaf, fi,
 648                                                         end - other_start);
 649                         btrfs_mark_buffer_dirty(leaf);
 650                         goto out;
 651                 }
 652         }
 653
 654         if (start > key.offset && end == extent_end) {
 655                 other_start = end;
 656                 other_end = 0;
 657                 if (extent_mergeable(leaf, path->slots[0] + 1,
 658                                      inode->i_ino, bytenr, orig_offset,
 659                                      &other_start, &other_end)) {
 660                         fi = btrfs_item_ptr(leaf, path->slots[0],
 661                                             struct btrfs_file_extent_item);
 662                         btrfs_set_file_extent_num_bytes(leaf, fi,
 663                                                         start - key.offset);
 664                         path->slots[0]++;
 665                         new_key.offset = start;
 666                         btrfs_set_item_key_safe(trans, root, path, &new_key);
 667
 668                         fi = btrfs_item_ptr(leaf, path->slots[0],
 669                                             struct btrfs_file_extent_item);
 670                         btrfs_set_file_extent_num_bytes(leaf, fi,
 671                                                         other_end - start);
 672                         btrfs_set_file_extent_offset(leaf, fi,
 673                                                      start - orig_offset);
 674                         btrfs_mark_buffer_dirty(leaf);
 675                         goto out;
 676                 }
 677         }
 678
 679         while (start > key.offset || end < extent_end) {
 680                 if (key.offset == start)
 681                         split = end;
 682
 683                 new_key.offset = split;
 684                 ret = btrfs_duplicate_item(trans, root, path, &new_key);
 685                 if (ret == -EAGAIN) {
 686                         btrfs_release_path(root, path);
 687                         goto again;
 688                 }
 689                 BUG_ON(ret < 0);
 690
 691                 leaf = path->nodes[0];
 692                 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
 693                                     struct btrfs_file_extent_item);
 694                 btrfs_set_file_extent_num_bytes(leaf, fi,
 695                                                 split - key.offset);
 696
 697                 fi = btrfs_item_ptr(leaf, path->slots[0],
 698                                     struct btrfs_file_extent_item);
 699
 700                 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
 701                 btrfs_set_file_extent_num_bytes(leaf, fi,
 702                                                 extent_end - split);
 703                 btrfs_mark_buffer_dirty(leaf);
 704
 705                 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
 706                                            root->root_key.objectid,
 707                                            inode->i_ino, orig_offset);
 708                 BUG_ON(ret);
 709
 710                 if (split == start) {
 711                         key.offset = start;
 712                 } else {
 713                         BUG_ON(start != key.offset);
 714                         path->slots[0]--;
 715                         extent_end = end;
 716                 }
 717                 recow = 1;
 718         }
 719
 720         other_start = end;
 721         other_end = 0;
 722         if (extent_mergeable(leaf, path->slots[0] + 1,
 723                              inode->i_ino, bytenr, orig_offset,
 724                              &other_start, &other_end)) {
 725                 if (recow) {
 726                         btrfs_release_path(root, path);
 727                         goto again;
 728                 }
 729                 extent_end = other_end;
 730                 del_slot = path->slots[0] + 1;
 731                 del_nr++;
 732                 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
 733                                         0, root->root_key.objectid,
 734                                         inode->i_ino, orig_offset);
 735                 BUG_ON(ret);
 736         }
 737         other_start = 0;
 738         other_end = start;
 739         if (extent_mergeable(leaf, path->slots[0] - 1,
 740                              inode->i_ino, bytenr, orig_offset,
 741                              &other_start, &other_end)) {
 742                 if (recow) {
 743                         btrfs_release_path(root, path);
 744                         goto again;
 745                 }
 746                 key.offset = other_start;
 747                 del_slot = path->slots[0];
 748                 del_nr++;
 749                 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
 750                                         0, root->root_key.objectid,
 751                                         inode->i_ino, orig_offset);
 752                 BUG_ON(ret);
 753         }
 754         if (del_nr == 0) {
 755                 fi = btrfs_item_ptr(leaf, path->slots[0],
 756                            struct btrfs_file_extent_item);
 757                 btrfs_set_file_extent_type(leaf, fi,
 758                                            BTRFS_FILE_EXTENT_REG);
 759                 btrfs_mark_buffer_dirty(leaf);
 760         } else {
 761                 fi = btrfs_item_ptr(leaf, del_slot - 1,
 762                            struct btrfs_file_extent_item);
 763                 btrfs_set_file_extent_type(leaf, fi,
 764                                            BTRFS_FILE_EXTENT_REG);
 765                 btrfs_set_file_extent_num_bytes(leaf, fi,
 766                                                 extent_end - key.offset);
 767                 btrfs_mark_buffer_dirty(leaf);
 768
 769                 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
 770                 BUG_ON(ret);
 771         }
 772 out:
 773         btrfs_free_path(path);
 774         return 0;
 775 }
 776
 777 /*
 778  * on error we return an unlocked page and the error value
 779  * on success we return a locked page and 0
 780  */
 781 static int prepare_uptodate_page(struct page *page, u64 pos)
 782 {
 783         int ret = 0;
 784
 785         if ((pos & (PAGE_CACHE_SIZE - 1)) && !PageUptodate(page)) {
 786                 ret = btrfs_readpage(NULL, page);
 787                 if (ret)
 788                         return ret;
 789                 lock_page(page);
 790                 if (!PageUptodate(page)) {
 791                         unlock_page(page);
 792                         return -EIO;
 793                 }
 794         }
 795         return 0;
 796 }
 797
 798 /*
 799  * this gets pages into the page cache and locks them down, it also properly
 800  * waits for data=ordered extents to finish before allowing the pages to be
 801  * modified.
 802  */
 803 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
 804                          struct page **pages, size_t num_pages,
 805                          loff_t pos, unsigned long first_index,
 806                          unsigned long last_index, size_t write_bytes)
 807 {
 808         struct extent_state *cached_state = NULL;
 809         int i;
 810         unsigned long index = pos >> PAGE_CACHE_SHIFT;
 811         struct inode *inode = fdentry(file)->d_inode;
 812         int err = 0;
 813         int faili = 0;
 814         u64 start_pos;
 815         u64 last_pos;
 816
 817         start_pos = pos & ~((u64)root->sectorsize - 1);
 818         last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
 819
 820         if (start_pos > inode->i_size) {
 821                 err = btrfs_cont_expand(inode, start_pos);
 822                 if (err)
 823                         return err;
 824         }
 825
 826         memset(pages, 0, num_pages * sizeof(struct page *));
 827 again:
 828         for (i = 0; i < num_pages; i++) {
 829                 pages[i] = grab_cache_page(inode->i_mapping, index + i);
 830                 if (!pages[i]) {
 831                         faili = i - 1;
 832                         err = -ENOMEM;
 833                         goto fail;
 834                 }
 835
 836                 if (i == 0)
 837                         err = prepare_uptodate_page(pages[i], pos);
 838                 if (i == num_pages - 1)
 839                         err = prepare_uptodate_page(pages[i],
 840                                                     pos + write_bytes);
 841                 if (err) {
 842                         page_cache_release(pages[i]);
 843                         faili = i - 1;
 844                         goto fail;
 845                 }
 846                 wait_on_page_writeback(pages[i]);
 847         }
 848         err = 0;
 849         if (start_pos < inode->i_size) {
 850                 struct btrfs_ordered_extent *ordered;
 851                 lock_extent_bits(&BTRFS_I(inode)->io_tree,
 852                                  start_pos, last_pos - 1, 0, &cached_state,
 853                                  GFP_NOFS);
 854                 ordered = btrfs_lookup_first_ordered_extent(inode,
 855                                                             last_pos - 1);
 856                 if (ordered &&
 857                     ordered->file_offset + ordered->len > start_pos &&
 858                     ordered->file_offset < last_pos) {
 859                         btrfs_put_ordered_extent(ordered);
 860                         unlock_extent_cached(&BTRFS_I(inode)->io_tree,
 861                                              start_pos, last_pos - 1,
 862                                              &cached_state, GFP_NOFS);
 863                         for (i = 0; i < num_pages; i++) {
 864                                 unlock_page(pages[i]);
 865                                 page_cache_release(pages[i]);
 866                         }
 867                         btrfs_wait_ordered_range(inode, start_pos,
 868                                                  last_pos - start_pos);
 869                         goto again;
 870                 }
 871                 if (ordered)
 872                         btrfs_put_ordered_extent(ordered);
 873
 874                 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
 875                                   last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
 876                                   EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
 877                                   GFP_NOFS);
 878                 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
 879                                      start_pos, last_pos - 1, &cached_state,
 880                                      GFP_NOFS);
 881         }
 882         for (i = 0; i < num_pages; i++) {
 883                 clear_page_dirty_for_io(pages[i]);
 884                 set_page_extent_mapped(pages[i]);
 885                 WARN_ON(!PageLocked(pages[i]));
 886         }
 887         return 0;
 888 fail:
 889         while (faili >= 0) {
 890                 unlock_page(pages[faili]);
 891                 page_cache_release(pages[faili]);
 892                 faili--;
 893         }
 894         return err;
 895
 896 }
 897
 898 static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
 899                                     const struct iovec *iov,
 900                                     unsigned long nr_segs, loff_t pos)
 901 {
 902         struct file *file = iocb->ki_filp;
 903         struct inode *inode = fdentry(file)->d_inode;
 904         struct btrfs_root *root = BTRFS_I(inode)->root;
 905         struct page **pages = NULL;
 906         struct iov_iter i;
 907         loff_t *ppos = &iocb->ki_pos;
 908         loff_t start_pos;
 909         ssize_t num_written = 0;
 910         ssize_t err = 0;
 911         size_t count;
 912         size_t ocount;
 913         int ret = 0;
 914         int nrptrs;
 915         unsigned long first_index;
 916         unsigned long last_index;
 917         int will_write;
 918         int buffered = 0;
 919         int copied = 0;
 920         int dirty_pages = 0;
 921
 922         will_write = ((file->f_flags & O_DSYNC) || IS_SYNC(inode) ||
 923                       (file->f_flags & O_DIRECT));
 924
 925         start_pos = pos;
 926
 927         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
 928
 929         mutex_lock(&inode->i_mutex);
 930
 931         err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
 932         if (err)
 933                 goto out;
 934         count = ocount;
 935
 936         current->backing_dev_info = inode->i_mapping->backing_dev_info;
 937         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
 938         if (err)
 939                 goto out;
 940
 941         if (count == 0)
 942                 goto out;
 943
 944         err = file_remove_suid(file);
 945         if (err)
 946                 goto out;
 947
 948         /*
 949          * If BTRFS flips readonly due to some impossible error
 950          * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
 951          * although we have opened a file as writable, we have
 952          * to stop this write operation to ensure FS consistency.
 953          */
 954         if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
 955                 err = -EROFS;
 956                 goto out;
 957         }
 958
 959         file_update_time(file);
 960         BTRFS_I(inode)->sequence++;
 961
 962         if (unlikely(file->f_flags & O_DIRECT)) {
 963                 num_written = generic_file_direct_write(iocb, iov, &nr_segs,
 964                                                         pos, ppos, count,
 965                                                         ocount);
 966                 /*
 967                  * the generic O_DIRECT will update in-memory i_size after the
 968                  * DIOs are done.  But our endio handlers that update the on
 969                  * disk i_size never update past the in memory i_size.  So we
 970                  * need one more update here to catch any additions to the
 971                  * file
 972                  */
 973                 if (inode->i_size != BTRFS_I(inode)->disk_i_size) {
 974                         btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
 975                         mark_inode_dirty(inode);
 976                 }
 977
 978                 if (num_written < 0) {
 979                         ret = num_written;
 980                         num_written = 0;
 981                         goto out;
 982                 } else if (num_written == count) {
 983                         /* pick up pos changes done by the generic code */
 984                         pos = *ppos;
 985                         goto out;
 986                 }
 987                 /*
 988                  * We are going to do buffered for the rest of the range, so we
 989                  * need to make sure to invalidate the buffered pages when we're
 990                  * done.
 991                  */
 992                 buffered = 1;
 993                 pos += num_written;
 994         }
 995
 996         iov_iter_init(&i, iov, nr_segs, count, num_written);
 997         nrptrs = min((iov_iter_count(&i) + PAGE_CACHE_SIZE - 1) /
 998                      PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
 999                      (sizeof(struct page *)));
1000         pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1001         if (!pages) {
1002                 ret = -ENOMEM;
1003                 goto out;
1004         }
1005
1006         /* generic_write_checks can change our pos */
1007         start_pos = pos;
1008
1009         first_index = pos >> PAGE_CACHE_SHIFT;
1010         last_index = (pos + iov_iter_count(&i)) >> PAGE_CACHE_SHIFT;
1011
1012         while (iov_iter_count(&i) > 0) {
1013                 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1014                 size_t write_bytes = min(iov_iter_count(&i),
1015                                          nrptrs * (size_t)PAGE_CACHE_SIZE -
1016                                          offset);
1017                 size_t num_pages = (write_bytes + offset +
1018                                     PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1019
1020                 WARN_ON(num_pages > nrptrs);
1021                 memset(pages, 0, sizeof(struct page *) * nrptrs);
1022
1023                 /*
1024                  * Fault pages before locking them in prepare_pages
1025                  * to avoid recursive lock
1026                  */
1027                 if (unlikely(iov_iter_fault_in_readable(&i, write_bytes))) {
1028                         ret = -EFAULT;
1029                         goto out;
1030                 }
1031
1032                 ret = btrfs_delalloc_reserve_space(inode,
1033                                         num_pages << PAGE_CACHE_SHIFT);
1034                 if (ret)
1035                         goto out;
1036
1037                 ret = prepare_pages(root, file, pages, num_pages,
1038                                     pos, first_index, last_index,
1039                                     write_bytes);
1040                 if (ret) {
1041                         btrfs_delalloc_release_space(inode,
1042                                         num_pages << PAGE_CACHE_SHIFT);
1043                         goto out;
1044                 }
1045
1046                 copied = btrfs_copy_from_user(pos, num_pages,
1047                                            write_bytes, pages, &i);
1048
1049                 /*
1050                  * if we have trouble faulting in the pages, fall
1051                  * back to one page at a time
1052                  */
1053                 if (copied < write_bytes)
1054                         nrptrs = 1;
1055
1056                 if (copied == 0)
1057                         dirty_pages = 0;
1058                 else
1059                         dirty_pages = (copied + offset +
1060                                        PAGE_CACHE_SIZE - 1) >>
1061                                        PAGE_CACHE_SHIFT;
1062
1063                 if (num_pages > dirty_pages) {
1064                         if (copied > 0)
1065                                 atomic_inc(
1066                                         &BTRFS_I(inode)->outstanding_extents);
1067                         btrfs_delalloc_release_space(inode,
1068                                         (num_pages - dirty_pages) <<
1069                                         PAGE_CACHE_SHIFT);
1070                 }
1071
1072                 if (copied > 0) {
1073                         dirty_and_release_pages(NULL, root, file, pages,
1074                                                 dirty_pages, pos, copied);
1075                 }
1076
1077                 btrfs_drop_pages(pages, num_pages);
1078
1079                 if (copied > 0) {
1080                         if (will_write) {
1081                                 filemap_fdatawrite_range(inode->i_mapping, pos,
1082                                                          pos + copied - 1);
1083                         } else {
1084                                 balance_dirty_pages_ratelimited_nr(
1085                                                         inode->i_mapping,
1086                                                         dirty_pages);
1087                                 if (dirty_pages <
1088                                 (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1089                                         btrfs_btree_balance_dirty(root, 1);
1090                                 btrfs_throttle(root);
1091                         }
1092                 }
1093
1094                 pos += copied;
1095                 num_written += copied;
1096
1097                 cond_resched();
1098         }
1099 out:
1100         mutex_unlock(&inode->i_mutex);
1101         if (ret)
1102                 err = ret;
1103
1104         kfree(pages);
1105         *ppos = pos;
1106
1107         /*
1108          * we want to make sure fsync finds this change
1109          * but we haven't joined a transaction running right now.
1110          *
1111          * Later on, someone is sure to update the inode and get the
1112          * real transid recorded.
1113          *
1114          * We set last_trans now to the fs_info generation + 1,
1115          * this will either be one more than the running transaction
1116          * or the generation used for the next transaction if there isn't
1117          * one running right now.
1118          */
1119         BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1120
1121         if (num_written > 0 && will_write) {
1122                 struct btrfs_trans_handle *trans;
1123
1124                 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1125                 if (err)
1126                         num_written = err;
1127
1128                 if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) {
1129                         trans = btrfs_start_transaction(root, 0);
1130                         if (IS_ERR(trans)) {
1131                                 num_written = PTR_ERR(trans);
1132                                 goto done;
1133                         }
1134                         mutex_lock(&inode->i_mutex);
1135                         ret = btrfs_log_dentry_safe(trans, root,
1136                                                     file->f_dentry);
1137                         mutex_unlock(&inode->i_mutex);
1138                         if (ret == 0) {
1139                                 ret = btrfs_sync_log(trans, root);
1140                                 if (ret == 0)
1141                                         btrfs_end_transaction(trans, root);
1142                                 else
1143                                         btrfs_commit_transaction(trans, root);
1144                         } else if (ret != BTRFS_NO_LOG_SYNC) {
1145                                 btrfs_commit_transaction(trans, root);
1146                         } else {
1147                                 btrfs_end_transaction(trans, root);
1148                         }
1149                 }
1150                 if (file->f_flags & O_DIRECT && buffered) {
1151                         invalidate_mapping_pages(inode->i_mapping,
1152                               start_pos >> PAGE_CACHE_SHIFT,
1153                              (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1154                 }
1155         }
1156 done:
1157         current->backing_dev_info = NULL;
1158         return num_written ? num_written : err;
1159 }
1160
1161 int btrfs_release_file(struct inode *inode, struct file *filp)
1162 {
1163         /*
1164          * ordered_data_close is set by settattr when we are about to truncate
1165          * a file from a non-zero size to a zero size.  This tries to
1166          * flush down new bytes that may have been written if the
1167          * application were using truncate to replace a file in place.
1168          */
1169         if (BTRFS_I(inode)->ordered_data_close) {
1170                 BTRFS_I(inode)->ordered_data_close = 0;
1171                 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1172                 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1173                         filemap_flush(inode->i_mapping);
1174         }
1175         if (filp->private_data)
1176                 btrfs_ioctl_trans_end(filp);
1177         return 0;
1178 }
1179
1180 /*
1181  * fsync call for both files and directories.  This logs the inode into
1182  * the tree log instead of forcing full commits whenever possible.
1183  *
1184  * It needs to call filemap_fdatawait so that all ordered extent updates are
1185  * in the metadata btree are up to date for copying to the log.
1186  *
1187  * It drops the inode mutex before doing the tree log commit.  This is an
1188  * important optimization for directories because holding the mutex prevents
1189  * new operations on the dir while we write to disk.
1190  */
1191 int btrfs_sync_file(struct file *file, int datasync)
1192 {
1193         struct dentry *dentry = file->f_path.dentry;
1194         struct inode *inode = dentry->d_inode;
1195         struct btrfs_root *root = BTRFS_I(inode)->root;
1196         int ret = 0;
1197         struct btrfs_trans_handle *trans;
1198
1199
1200         /* we wait first, since the writeback may change the inode */
1201         root->log_batch++;
1202         /* the VFS called filemap_fdatawrite for us */
1203         btrfs_wait_ordered_range(inode, 0, (u64)-1);
1204         root->log_batch++;
1205
1206         /*
1207          * check the transaction that last modified this inode
1208          * and see if its already been committed
1209          */
1210         if (!BTRFS_I(inode)->last_trans)
1211                 goto out;
1212
1213         /*
1214          * if the last transaction that changed this file was before
1215          * the current transaction, we can bail out now without any
1216          * syncing
1217          */
1218         mutex_lock(&root->fs_info->trans_mutex);
1219         if (BTRFS_I(inode)->last_trans <=
1220             root->fs_info->last_trans_committed) {
1221                 BTRFS_I(inode)->last_trans = 0;
1222                 mutex_unlock(&root->fs_info->trans_mutex);
1223                 goto out;
1224         }
1225         mutex_unlock(&root->fs_info->trans_mutex);
1226
1227         /*
1228          * ok we haven't committed the transaction yet, lets do a commit
1229          */
1230         if (file->private_data)
1231                 btrfs_ioctl_trans_end(file);
1232
1233         trans = btrfs_start_transaction(root, 0);
1234         if (IS_ERR(trans)) {
1235                 ret = PTR_ERR(trans);
1236                 goto out;
1237         }
1238
1239         ret = btrfs_log_dentry_safe(trans, root, dentry);
1240         if (ret < 0)
1241                 goto out;
1242
1243         /* we've logged all the items and now have a consistent
1244          * version of the file in the log.  It is possible that
1245          * someone will come in and modify the file, but that's
1246          * fine because the log is consistent on disk, and we
1247          * have references to all of the file's extents
1248          *
1249          * It is possible that someone will come in and log the
1250          * file again, but that will end up using the synchronization
1251          * inside btrfs_sync_log to keep things safe.
1252          */
1253         mutex_unlock(&dentry->d_inode->i_mutex);
1254
1255         if (ret != BTRFS_NO_LOG_SYNC) {
1256                 if (ret > 0) {
1257                         ret = btrfs_commit_transaction(trans, root);
1258                 } else {
1259                         ret = btrfs_sync_log(trans, root);
1260                         if (ret == 0)
1261                                 ret = btrfs_end_transaction(trans, root);
1262                         else
1263                                 ret = btrfs_commit_transaction(trans, root);
1264                 }
1265         } else {
1266                 ret = btrfs_end_transaction(trans, root);
1267         }
1268         mutex_lock(&dentry->d_inode->i_mutex);
1269 out:
1270         return ret > 0 ? -EIO : ret;
1271 }
1272
1273 static const struct vm_operations_struct btrfs_file_vm_ops = {
1274         .fault          = filemap_fault,
1275         .page_mkwrite   = btrfs_page_mkwrite,
1276 };
1277
1278 static int btrfs_file_mmap(struct file  *filp, struct vm_area_struct *vma)
1279 {
1280         struct address_space *mapping = filp->f_mapping;
1281
1282         if (!mapping->a_ops->readpage)
1283                 return -ENOEXEC;
1284
1285         file_accessed(filp);
1286         vma->vm_ops = &btrfs_file_vm_ops;
1287         vma->vm_flags |= VM_CAN_NONLINEAR;
1288
1289         return 0;
1290 }
1291
1292 const struct file_operations btrfs_file_operations = {
1293         .llseek         = generic_file_llseek,
1294         .read           = do_sync_read,
1295         .write          = do_sync_write,
1296         .aio_read       = generic_file_aio_read,
1297         .splice_read    = generic_file_splice_read,
1298         .aio_write      = btrfs_file_aio_write,
1299         .mmap           = btrfs_file_mmap,
1300         .open           = generic_file_open,
1301         .release        = btrfs_release_file,
1302         .fsync          = btrfs_sync_file,
1303         .unlocked_ioctl = btrfs_ioctl,
1304 #ifdef CONFIG_COMPAT
1305         .compat_ioctl   = btrfs_ioctl,
1306 #endif
1307 };