SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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/smp_lock.h>
  26 #include <linux/backing-dev.h>
  27 #include <linux/mpage.h>
  28 #include <linux/swap.h>
  29 #include <linux/writeback.h>
  30 #include <linux/statfs.h>
  31 #include <linux/compat.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                                          const char __user *buf)
  50 {
  51         long page_fault = 0;
  52         int i;
  53         int offset = pos & (PAGE_CACHE_SIZE - 1);
  54
  55         for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
  56                 size_t count = min_t(size_t,
  57                                      PAGE_CACHE_SIZE - offset, write_bytes);
  58                 struct page *page = prepared_pages[i];
  59                 fault_in_pages_readable(buf, count);
  60
  61                 /* Copy data from userspace to the current page */
  62                 kmap(page);
  63                 page_fault = __copy_from_user(page_address(page) + offset,
  64                                               buf, count);
  65                 /* Flush processor's dcache for this page */
  66                 flush_dcache_page(page);
  67                 kunmap(page);
  68                 buf += count;
  69                 write_bytes -= count;
  70
  71                 if (page_fault)
  72                         break;
  73         }
  74         return page_fault ? -EFAULT : 0;
  75 }
  76
  77 /*
  78  * unlocks pages after btrfs_file_write is done with them
  79  */
  80 static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages)
  81 {
  82         size_t i;
  83         for (i = 0; i < num_pages; i++) {
  84                 if (!pages[i])
  85                         break;
  86                 /* page checked is some magic around finding pages that
  87                  * have been modified without going through btrfs_set_page_dirty
  88                  * clear it here
  89                  */
  90                 ClearPageChecked(pages[i]);
  91                 unlock_page(pages[i]);
  92                 mark_page_accessed(pages[i]);
  93                 page_cache_release(pages[i]);
  94         }
  95 }
  96
  97 /*
  98  * after copy_from_user, pages need to be dirtied and we need to make
  99  * sure holes are created between the current EOF and the start of
 100  * any next extents (if required).
 101  *
 102  * this also makes the decision about creating an inline extent vs
 103  * doing real data extents, marking pages dirty and delalloc as required.
 104  */
 105 static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
 106                                    struct btrfs_root *root,
 107                                    struct file *file,
 108                                    struct page **pages,
 109                                    size_t num_pages,
 110                                    loff_t pos,
 111                                    size_t write_bytes)
 112 {
 113         int err = 0;
 114         int i;
 115         struct inode *inode = fdentry(file)->d_inode;
 116         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 117         u64 hint_byte;
 118         u64 num_bytes;
 119         u64 start_pos;
 120         u64 end_of_last_block;
 121         u64 end_pos = pos + write_bytes;
 122         loff_t isize = i_size_read(inode);
 123
 124         start_pos = pos & ~((u64)root->sectorsize - 1);
 125         num_bytes = (write_bytes + pos - start_pos +
 126                     root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
 127
 128         end_of_last_block = start_pos + num_bytes - 1;
 129
 130         lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 131         trans = btrfs_join_transaction(root, 1);
 132         if (!trans) {
 133                 err = -ENOMEM;
 134                 goto out_unlock;
 135         }
 136         btrfs_set_trans_block_group(trans, inode);
 137         hint_byte = 0;
 138
 139         set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 140
 141         /* check for reserved extents on each page, we don't want
 142          * to reset the delalloc bit on things that already have
 143          * extents reserved.
 144          */
 145         btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
 146         for (i = 0; i < num_pages; i++) {
 147                 struct page *p = pages[i];
 148                 SetPageUptodate(p);
 149                 ClearPageChecked(p);
 150                 set_page_dirty(p);
 151         }
 152         if (end_pos > isize) {
 153                 i_size_write(inode, end_pos);
 154                 btrfs_update_inode(trans, root, inode);
 155         }
 156         err = btrfs_end_transaction(trans, root);
 157 out_unlock:
 158         unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 159         return err;
 160 }
 161
 162 /*
 163  * this drops all the extents in the cache that intersect the range
 164  * [start, end].  Existing extents are split as required.
 165  */
 166 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
 167                             int skip_pinned)
 168 {
 169         struct extent_map *em;
 170         struct extent_map *split = NULL;
 171         struct extent_map *split2 = NULL;
 172         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 173         u64 len = end - start + 1;
 174         int ret;
 175         int testend = 1;
 176         unsigned long flags;
 177         int compressed = 0;
 178
 179         WARN_ON(end < start);
 180         if (end == (u64)-1) {
 181                 len = (u64)-1;
 182                 testend = 0;
 183         }
 184         while (1) {
 185                 if (!split)
 186                         split = alloc_extent_map(GFP_NOFS);
 187                 if (!split2)
 188                         split2 = alloc_extent_map(GFP_NOFS);
 189
 190                 spin_lock(&em_tree->lock);
 191                 em = lookup_extent_mapping(em_tree, start, len);
 192                 if (!em) {
 193                         spin_unlock(&em_tree->lock);
 194                         break;
 195                 }
 196                 flags = em->flags;
 197                 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
 198                         spin_unlock(&em_tree->lock);
 199                         if (em->start <= start &&
 200                             (!testend || em->start + em->len >= start + len)) {
 201                                 free_extent_map(em);
 202                                 break;
 203                         }
 204                         if (start < em->start) {
 205                                 len = em->start - start;
 206                         } else {
 207                                 len = start + len - (em->start + em->len);
 208                                 start = em->start + em->len;
 209                         }
 210                         free_extent_map(em);
 211                         continue;
 212                 }
 213                 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 214                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
 215                 remove_extent_mapping(em_tree, em);
 216
 217                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 218                     em->start < start) {
 219                         split->start = em->start;
 220                         split->len = start - em->start;
 221                         split->orig_start = em->orig_start;
 222                         split->block_start = em->block_start;
 223
 224                         if (compressed)
 225                                 split->block_len = em->block_len;
 226                         else
 227                                 split->block_len = split->len;
 228
 229                         split->bdev = em->bdev;
 230                         split->flags = flags;
 231                         ret = add_extent_mapping(em_tree, split);
 232                         BUG_ON(ret);
 233                         free_extent_map(split);
 234                         split = split2;
 235                         split2 = NULL;
 236                 }
 237                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 238                     testend && em->start + em->len > start + len) {
 239                         u64 diff = start + len - em->start;
 240
 241                         split->start = start + len;
 242                         split->len = em->start + em->len - (start + len);
 243                         split->bdev = em->bdev;
 244                         split->flags = flags;
 245
 246                         if (compressed) {
 247                                 split->block_len = em->block_len;
 248                                 split->block_start = em->block_start;
 249                                 split->orig_start = em->orig_start;
 250                         } else {
 251                                 split->block_len = split->len;
 252                                 split->block_start = em->block_start + diff;
 253                                 split->orig_start = split->start;
 254                         }
 255
 256                         ret = add_extent_mapping(em_tree, split);
 257                         BUG_ON(ret);
 258                         free_extent_map(split);
 259                         split = NULL;
 260                 }
 261                 spin_unlock(&em_tree->lock);
 262
 263                 /* once for us */
 264                 free_extent_map(em);
 265                 /* once for the tree*/
 266                 free_extent_map(em);
 267         }
 268         if (split)
 269                 free_extent_map(split);
 270         if (split2)
 271                 free_extent_map(split2);
 272         return 0;
 273 }
 274
 275 /*
 276  * this is very complex, but the basic idea is to drop all extents
 277  * in the range start - end.  hint_block is filled in with a block number
 278  * that would be a good hint to the block allocator for this file.
 279  *
 280  * If an extent intersects the range but is not entirely inside the range
 281  * it is either truncated or split.  Anything entirely inside the range
 282  * is deleted from the tree.
 283  *
 284  * inline_limit is used to tell this code which offsets in the file to keep
 285  * if they contain inline extents.
 286  */
 287 noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 288                        struct btrfs_root *root, struct inode *inode,
 289                        u64 start, u64 end, u64 locked_end,
 290                        u64 inline_limit, u64 *hint_byte)
 291 {
 292         u64 extent_end = 0;
 293         u64 search_start = start;
 294         u64 leaf_start;
 295         u64 ram_bytes = 0;
 296         u64 orig_parent = 0;
 297         u64 disk_bytenr = 0;
 298         u64 orig_locked_end = locked_end;
 299         u8 compression;
 300         u8 encryption;
 301         u16 other_encoding = 0;
 302         u64 root_gen;
 303         u64 root_owner;
 304         struct extent_buffer *leaf;
 305         struct btrfs_file_extent_item *extent;
 306         struct btrfs_path *path;
 307         struct btrfs_key key;
 308         struct btrfs_file_extent_item old;
 309         int keep;
 310         int slot;
 311         int bookend;
 312         int found_type = 0;
 313         int found_extent;
 314         int found_inline;
 315         int recow;
 316         int ret;
 317
 318         inline_limit = 0;
 319         btrfs_drop_extent_cache(inode, start, end - 1, 0);
 320
 321         path = btrfs_alloc_path();
 322         if (!path)
 323                 return -ENOMEM;
 324         while (1) {
 325                 recow = 0;
 326                 btrfs_release_path(root, path);
 327                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
 328                                                search_start, -1);
 329                 if (ret < 0)
 330                         goto out;
 331                 if (ret > 0) {
 332                         if (path->slots[0] == 0) {
 333                                 ret = 0;
 334                                 goto out;
 335                         }
 336                         path->slots[0]--;
 337                 }
 338 next_slot:
 339                 keep = 0;
 340                 bookend = 0;
 341                 found_extent = 0;
 342                 found_inline = 0;
 343                 leaf_start = 0;
 344                 root_gen = 0;
 345                 root_owner = 0;
 346                 compression = 0;
 347                 encryption = 0;
 348                 extent = NULL;
 349                 leaf = path->nodes[0];
 350                 slot = path->slots[0];
 351                 ret = 0;
 352                 btrfs_item_key_to_cpu(leaf, &key, slot);
 353                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
 354                     key.offset >= end) {
 355                         goto out;
 356                 }
 357                 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
 358                     key.objectid != inode->i_ino) {
 359                         goto out;
 360                 }
 361                 if (recow) {
 362                         search_start = max(key.offset, start);
 363                         continue;
 364                 }
 365                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
 366                         extent = btrfs_item_ptr(leaf, slot,
 367                                                 struct btrfs_file_extent_item);
 368                         found_type = btrfs_file_extent_type(leaf, extent);
 369                         compression = btrfs_file_extent_compression(leaf,
 370                                                                     extent);
 371                         encryption = btrfs_file_extent_encryption(leaf,
 372                                                                   extent);
 373                         other_encoding = btrfs_file_extent_other_encoding(leaf,
 374                                                                   extent);
 375                         if (found_type == BTRFS_FILE_EXTENT_REG ||
 376                             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
 377                                 extent_end =
 378                                      btrfs_file_extent_disk_bytenr(leaf,
 379                                                                    extent);
 380                                 if (extent_end)
 381                                         *hint_byte = extent_end;
 382
 383                                 extent_end = key.offset +
 384                                      btrfs_file_extent_num_bytes(leaf, extent);
 385                                 ram_bytes = btrfs_file_extent_ram_bytes(leaf,
 386                                                                 extent);
 387                                 found_extent = 1;
 388                         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 389                                 found_inline = 1;
 390                                 extent_end = key.offset +
 391                                      btrfs_file_extent_inline_len(leaf, extent);
 392                         }
 393                 } else {
 394                         extent_end = search_start;
 395                 }
 396
 397                 /* we found nothing we can drop */
 398                 if ((!found_extent && !found_inline) ||
 399                     search_start >= extent_end) {
 400                         int nextret;
 401                         u32 nritems;
 402                         nritems = btrfs_header_nritems(leaf);
 403                         if (slot >= nritems - 1) {
 404                                 nextret = btrfs_next_leaf(root, path);
 405                                 if (nextret)
 406                                         goto out;
 407                                 recow = 1;
 408                         } else {
 409                                 path->slots[0]++;
 410                         }
 411                         goto next_slot;
 412                 }
 413
 414                 if (end <= extent_end && start >= key.offset && found_inline)
 415                         *hint_byte = EXTENT_MAP_INLINE;
 416
 417                 if (found_extent) {
 418                         read_extent_buffer(leaf, &old, (unsigned long)extent,
 419                                            sizeof(old));
 420                         root_gen = btrfs_header_generation(leaf);
 421                         root_owner = btrfs_header_owner(leaf);
 422                         leaf_start = leaf->start;
 423                 }
 424
 425                 if (end < extent_end && end >= key.offset) {
 426                         bookend = 1;
 427                         if (found_inline && start <= key.offset)
 428                                 keep = 1;
 429                 }
 430
 431                 if (bookend && found_extent) {
 432                         if (locked_end < extent_end) {
 433                                 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
 434                                                 locked_end, extent_end - 1,
 435                                                 GFP_NOFS);
 436                                 if (!ret) {
 437                                         btrfs_release_path(root, path);
 438                                         lock_extent(&BTRFS_I(inode)->io_tree,
 439                                                 locked_end, extent_end - 1,
 440                                                 GFP_NOFS);
 441                                         locked_end = extent_end;
 442                                         continue;
 443                                 }
 444                                 locked_end = extent_end;
 445                         }
 446                         orig_parent = path->nodes[0]->start;
 447                         disk_bytenr = le64_to_cpu(old.disk_bytenr);
 448                         if (disk_bytenr != 0) {
 449                                 ret = btrfs_inc_extent_ref(trans, root,
 450                                            disk_bytenr,
 451                                            le64_to_cpu(old.disk_num_bytes),
 452                                            orig_parent, root->root_key.objectid,
 453                                            trans->transid, inode->i_ino);
 454                                 BUG_ON(ret);
 455                         }
 456                 }
 457
 458                 if (found_inline) {
 459                         u64 mask = root->sectorsize - 1;
 460                         search_start = (extent_end + mask) & ~mask;
 461                 } else
 462                         search_start = extent_end;
 463
 464                 /* truncate existing extent */
 465                 if (start > key.offset) {
 466                         u64 new_num;
 467                         u64 old_num;
 468                         keep = 1;
 469                         WARN_ON(start & (root->sectorsize - 1));
 470                         if (found_extent) {
 471                                 new_num = start - key.offset;
 472                                 old_num = btrfs_file_extent_num_bytes(leaf,
 473                                                                       extent);
 474                                 *hint_byte =
 475                                         btrfs_file_extent_disk_bytenr(leaf,
 476                                                                       extent);
 477                                 if (btrfs_file_extent_disk_bytenr(leaf,
 478                                                                   extent)) {
 479                                         inode_sub_bytes(inode, old_num -
 480                                                         new_num);
 481                                 }
 482                                 btrfs_set_file_extent_num_bytes(leaf,
 483                                                         extent, new_num);
 484                                 btrfs_mark_buffer_dirty(leaf);
 485                         } else if (key.offset < inline_limit &&
 486                                    (end > extent_end) &&
 487                                    (inline_limit < extent_end)) {
 488                                 u32 new_size;
 489                                 new_size = btrfs_file_extent_calc_inline_size(
 490                                                    inline_limit - key.offset);
 491                                 inode_sub_bytes(inode, extent_end -
 492                                                 inline_limit);
 493                                 btrfs_set_file_extent_ram_bytes(leaf, extent,
 494                                                         new_size);
 495                                 if (!compression && !encryption) {
 496                                         btrfs_truncate_item(trans, root, path,
 497                                                             new_size, 1);
 498                                 }
 499                         }
 500                 }
 501                 /* delete the entire extent */
 502                 if (!keep) {
 503                         if (found_inline)
 504                                 inode_sub_bytes(inode, extent_end -
 505                                                 key.offset);
 506                         ret = btrfs_del_item(trans, root, path);
 507                         /* TODO update progress marker and return */
 508                         BUG_ON(ret);
 509                         extent = NULL;
 510                         btrfs_release_path(root, path);
 511                         /* the extent will be freed later */
 512                 }
 513                 if (bookend && found_inline && start <= key.offset) {
 514                         u32 new_size;
 515                         new_size = btrfs_file_extent_calc_inline_size(
 516                                                    extent_end - end);
 517                         inode_sub_bytes(inode, end - key.offset);
 518                         btrfs_set_file_extent_ram_bytes(leaf, extent,
 519                                                         new_size);
 520                         if (!compression && !encryption)
 521                                 ret = btrfs_truncate_item(trans, root, path,
 522                                                           new_size, 0);
 523                         BUG_ON(ret);
 524                 }
 525                 /* create bookend, splitting the extent in two */
 526                 if (bookend && found_extent) {
 527                         struct btrfs_key ins;
 528                         ins.objectid = inode->i_ino;
 529                         ins.offset = end;
 530                         btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
 531
 532                         btrfs_release_path(root, path);
 533                         path->leave_spinning = 1;
 534                         ret = btrfs_insert_empty_item(trans, root, path, &ins,
 535                                                       sizeof(*extent));
 536                         BUG_ON(ret);
 537
 538                         leaf = path->nodes[0];
 539                         extent = btrfs_item_ptr(leaf, path->slots[0],
 540                                                 struct btrfs_file_extent_item);
 541                         write_extent_buffer(leaf, &old,
 542                                             (unsigned long)extent, sizeof(old));
 543
 544                         btrfs_set_file_extent_compression(leaf, extent,
 545                                                           compression);
 546                         btrfs_set_file_extent_encryption(leaf, extent,
 547                                                          encryption);
 548                         btrfs_set_file_extent_other_encoding(leaf, extent,
 549                                                              other_encoding);
 550                         btrfs_set_file_extent_offset(leaf, extent,
 551                                     le64_to_cpu(old.offset) + end - key.offset);
 552                         WARN_ON(le64_to_cpu(old.num_bytes) <
 553                                 (extent_end - end));
 554                         btrfs_set_file_extent_num_bytes(leaf, extent,
 555                                                         extent_end - end);
 556
 557                         /*
 558                          * set the ram bytes to the size of the full extent
 559                          * before splitting.  This is a worst case flag,
 560                          * but its the best we can do because we don't know
 561                          * how splitting affects compression
 562                          */
 563                         btrfs_set_file_extent_ram_bytes(leaf, extent,
 564                                                         ram_bytes);
 565                         btrfs_set_file_extent_type(leaf, extent, found_type);
 566
 567                         btrfs_unlock_up_safe(path, 1);
 568                         btrfs_mark_buffer_dirty(path->nodes[0]);
 569                         btrfs_set_lock_blocking(path->nodes[0]);
 570
 571                         if (disk_bytenr != 0) {
 572                                 ret = btrfs_update_extent_ref(trans, root,
 573                                                 disk_bytenr,
 574                                                 le64_to_cpu(old.disk_num_bytes),
 575                                                 orig_parent,
 576                                                 leaf->start,
 577                                                 root->root_key.objectid,
 578                                                 trans->transid, ins.objectid);
 579
 580                                 BUG_ON(ret);
 581                         }
 582                         path->leave_spinning = 0;
 583                         btrfs_release_path(root, path);
 584                         if (disk_bytenr != 0)
 585                                 inode_add_bytes(inode, extent_end - end);
 586                 }
 587
 588                 if (found_extent && !keep) {
 589                         u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr);
 590
 591                         if (old_disk_bytenr != 0) {
 592                                 inode_sub_bytes(inode,
 593                                                 le64_to_cpu(old.num_bytes));
 594                                 ret = btrfs_free_extent(trans, root,
 595                                                 old_disk_bytenr,
 596                                                 le64_to_cpu(old.disk_num_bytes),
 597                                                 leaf_start, root_owner,
 598                                                 root_gen, key.objectid, 0);
 599                                 BUG_ON(ret);
 600                                 *hint_byte = old_disk_bytenr;
 601                         }
 602                 }
 603
 604                 if (search_start >= end) {
 605                         ret = 0;
 606                         goto out;
 607                 }
 608         }
 609 out:
 610         btrfs_free_path(path);
 611         if (locked_end > orig_locked_end) {
 612                 unlock_extent(&BTRFS_I(inode)->io_tree, orig_locked_end,
 613                               locked_end - 1, GFP_NOFS);
 614         }
 615         return ret;
 616 }
 617
 618 static int extent_mergeable(struct extent_buffer *leaf, int slot,
 619                             u64 objectid, u64 bytenr, u64 *start, u64 *end)
 620 {
 621         struct btrfs_file_extent_item *fi;
 622         struct btrfs_key key;
 623         u64 extent_end;
 624
 625         if (slot < 0 || slot >= btrfs_header_nritems(leaf))
 626                 return 0;
 627
 628         btrfs_item_key_to_cpu(leaf, &key, slot);
 629         if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
 630                 return 0;
 631
 632         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
 633         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
 634             btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
 635             btrfs_file_extent_compression(leaf, fi) ||
 636             btrfs_file_extent_encryption(leaf, fi) ||
 637             btrfs_file_extent_other_encoding(leaf, fi))
 638                 return 0;
 639
 640         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
 641         if ((*start && *start != key.offset) || (*end && *end != extent_end))
 642                 return 0;
 643
 644         *start = key.offset;
 645         *end = extent_end;
 646         return 1;
 647 }
 648
 649 /*
 650  * Mark extent in the range start - end as written.
 651  *
 652  * This changes extent type from 'pre-allocated' to 'regular'. If only
 653  * part of extent is marked as written, the extent will be split into
 654  * two or three.
 655  */
 656 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
 657                               struct btrfs_root *root,
 658                               struct inode *inode, u64 start, u64 end)
 659 {
 660         struct extent_buffer *leaf;
 661         struct btrfs_path *path;
 662         struct btrfs_file_extent_item *fi;
 663         struct btrfs_key key;
 664         u64 bytenr;
 665         u64 num_bytes;
 666         u64 extent_end;
 667         u64 extent_offset;
 668         u64 other_start;
 669         u64 other_end;
 670         u64 split = start;
 671         u64 locked_end = end;
 672         u64 orig_parent;
 673         int extent_type;
 674         int split_end = 1;
 675         int ret;
 676
 677         btrfs_drop_extent_cache(inode, start, end - 1, 0);
 678
 679         path = btrfs_alloc_path();
 680         BUG_ON(!path);
 681 again:
 682         key.objectid = inode->i_ino;
 683         key.type = BTRFS_EXTENT_DATA_KEY;
 684         if (split == start)
 685                 key.offset = split;
 686         else
 687                 key.offset = split - 1;
 688
 689         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 690         if (ret > 0 && path->slots[0] > 0)
 691                 path->slots[0]--;
 692
 693         leaf = path->nodes[0];
 694         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 695         BUG_ON(key.objectid != inode->i_ino ||
 696                key.type != BTRFS_EXTENT_DATA_KEY);
 697         fi = btrfs_item_ptr(leaf, path->slots[0],
 698                             struct btrfs_file_extent_item);
 699         extent_type = btrfs_file_extent_type(leaf, fi);
 700         BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC);
 701         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
 702         BUG_ON(key.offset > start || extent_end < end);
 703
 704         bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
 705         num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
 706         extent_offset = btrfs_file_extent_offset(leaf, fi);
 707
 708         if (key.offset == start)
 709                 split = end;
 710
 711         if (key.offset == start && extent_end == end) {
 712                 int del_nr = 0;
 713                 int del_slot = 0;
 714                 u64 leaf_owner = btrfs_header_owner(leaf);
 715                 u64 leaf_gen = btrfs_header_generation(leaf);
 716                 other_start = end;
 717                 other_end = 0;
 718                 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
 719                                      bytenr, &other_start, &other_end)) {
 720                         extent_end = other_end;
 721                         del_slot = path->slots[0] + 1;
 722                         del_nr++;
 723                         ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
 724                                                 leaf->start, leaf_owner,
 725                                                 leaf_gen, inode->i_ino, 0);
 726                         BUG_ON(ret);
 727                 }
 728                 other_start = 0;
 729                 other_end = start;
 730                 if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino,
 731                                      bytenr, &other_start, &other_end)) {
 732                         key.offset = other_start;
 733                         del_slot = path->slots[0];
 734                         del_nr++;
 735                         ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
 736                                                 leaf->start, leaf_owner,
 737                                                 leaf_gen, inode->i_ino, 0);
 738                         BUG_ON(ret);
 739                 }
 740                 split_end = 0;
 741                 if (del_nr == 0) {
 742                         btrfs_set_file_extent_type(leaf, fi,
 743                                                    BTRFS_FILE_EXTENT_REG);
 744                         goto done;
 745                 }
 746
 747                 fi = btrfs_item_ptr(leaf, del_slot - 1,
 748                                     struct btrfs_file_extent_item);
 749                 btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
 750                 btrfs_set_file_extent_num_bytes(leaf, fi,
 751                                                 extent_end - key.offset);
 752                 btrfs_mark_buffer_dirty(leaf);
 753
 754                 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
 755                 BUG_ON(ret);
 756                 goto release;
 757         } else if (split == start) {
 758                 if (locked_end < extent_end) {
 759                         ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
 760                                         locked_end, extent_end - 1, GFP_NOFS);
 761                         if (!ret) {
 762                                 btrfs_release_path(root, path);
 763                                 lock_extent(&BTRFS_I(inode)->io_tree,
 764                                         locked_end, extent_end - 1, GFP_NOFS);
 765                                 locked_end = extent_end;
 766                                 goto again;
 767                         }
 768                         locked_end = extent_end;
 769                 }
 770                 btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
 771                 extent_offset += split - key.offset;
 772         } else  {
 773                 BUG_ON(key.offset != start);
 774                 btrfs_set_file_extent_offset(leaf, fi, extent_offset +
 775                                              split - key.offset);
 776                 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
 777                 key.offset = split;
 778                 btrfs_set_item_key_safe(trans, root, path, &key);
 779                 extent_end = split;
 780         }
 781
 782         if (extent_end == end) {
 783                 split_end = 0;
 784                 extent_type = BTRFS_FILE_EXTENT_REG;
 785         }
 786         if (extent_end == end && split == start) {
 787                 other_start = end;
 788                 other_end = 0;
 789                 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
 790                                      bytenr, &other_start, &other_end)) {
 791                         path->slots[0]++;
 792                         fi = btrfs_item_ptr(leaf, path->slots[0],
 793                                             struct btrfs_file_extent_item);
 794                         key.offset = split;
 795                         btrfs_set_item_key_safe(trans, root, path, &key);
 796                         btrfs_set_file_extent_offset(leaf, fi, extent_offset);
 797                         btrfs_set_file_extent_num_bytes(leaf, fi,
 798                                                         other_end - split);
 799                         goto done;
 800                 }
 801         }
 802         if (extent_end == end && split == end) {
 803                 other_start = 0;
 804                 other_end = start;
 805                 if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino,
 806                                      bytenr, &other_start, &other_end)) {
 807                         path->slots[0]--;
 808                         fi = btrfs_item_ptr(leaf, path->slots[0],
 809                                             struct btrfs_file_extent_item);
 810                         btrfs_set_file_extent_num_bytes(leaf, fi, extent_end -
 811                                                         other_start);
 812                         goto done;
 813                 }
 814         }
 815
 816         btrfs_mark_buffer_dirty(leaf);
 817
 818         orig_parent = leaf->start;
 819         ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
 820                                    orig_parent, root->root_key.objectid,
 821                                    trans->transid, inode->i_ino);
 822         BUG_ON(ret);
 823         btrfs_release_path(root, path);
 824
 825         key.offset = start;
 826         ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi));
 827         BUG_ON(ret);
 828
 829         leaf = path->nodes[0];
 830         fi = btrfs_item_ptr(leaf, path->slots[0],
 831                             struct btrfs_file_extent_item);
 832         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
 833         btrfs_set_file_extent_type(leaf, fi, extent_type);
 834         btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr);
 835         btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
 836         btrfs_set_file_extent_offset(leaf, fi, extent_offset);
 837         btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset);
 838         btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
 839         btrfs_set_file_extent_compression(leaf, fi, 0);
 840         btrfs_set_file_extent_encryption(leaf, fi, 0);
 841         btrfs_set_file_extent_other_encoding(leaf, fi, 0);
 842
 843         if (orig_parent != leaf->start) {
 844                 ret = btrfs_update_extent_ref(trans, root, bytenr, num_bytes,
 845                                               orig_parent, leaf->start,
 846                                               root->root_key.objectid,
 847                                               trans->transid, inode->i_ino);
 848                 BUG_ON(ret);
 849         }
 850 done:
 851         btrfs_mark_buffer_dirty(leaf);
 852
 853 release:
 854         btrfs_release_path(root, path);
 855         if (split_end && split == start) {
 856                 split = end;
 857                 goto again;
 858         }
 859         if (locked_end > end) {
 860                 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
 861                               GFP_NOFS);
 862         }
 863         btrfs_free_path(path);
 864         return 0;
 865 }
 866
 867 /*
 868  * this gets pages into the page cache and locks them down, it also properly
 869  * waits for data=ordered extents to finish before allowing the pages to be
 870  * modified.
 871  */
 872 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
 873                          struct page **pages, size_t num_pages,
 874                          loff_t pos, unsigned long first_index,
 875                          unsigned long last_index, size_t write_bytes)
 876 {
 877         int i;
 878         unsigned long index = pos >> PAGE_CACHE_SHIFT;
 879         struct inode *inode = fdentry(file)->d_inode;
 880         int err = 0;
 881         u64 start_pos;
 882         u64 last_pos;
 883
 884         start_pos = pos & ~((u64)root->sectorsize - 1);
 885         last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
 886
 887         if (start_pos > inode->i_size) {
 888                 err = btrfs_cont_expand(inode, start_pos);
 889                 if (err)
 890                         return err;
 891         }
 892
 893         memset(pages, 0, num_pages * sizeof(struct page *));
 894 again:
 895         for (i = 0; i < num_pages; i++) {
 896                 pages[i] = grab_cache_page(inode->i_mapping, index + i);
 897                 if (!pages[i]) {
 898                         err = -ENOMEM;
 899                         BUG_ON(1);
 900                 }
 901                 wait_on_page_writeback(pages[i]);
 902         }
 903         if (start_pos < inode->i_size) {
 904                 struct btrfs_ordered_extent *ordered;
 905                 lock_extent(&BTRFS_I(inode)->io_tree,
 906                             start_pos, last_pos - 1, GFP_NOFS);
 907                 ordered = btrfs_lookup_first_ordered_extent(inode,
 908                                                             last_pos - 1);
 909                 if (ordered &&
 910                     ordered->file_offset + ordered->len > start_pos &&
 911                     ordered->file_offset < last_pos) {
 912                         btrfs_put_ordered_extent(ordered);
 913                         unlock_extent(&BTRFS_I(inode)->io_tree,
 914                                       start_pos, last_pos - 1, GFP_NOFS);
 915                         for (i = 0; i < num_pages; i++) {
 916                                 unlock_page(pages[i]);
 917                                 page_cache_release(pages[i]);
 918                         }
 919                         btrfs_wait_ordered_range(inode, start_pos,
 920                                                  last_pos - start_pos);
 921                         goto again;
 922                 }
 923                 if (ordered)
 924                         btrfs_put_ordered_extent(ordered);
 925
 926                 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
 927                                   last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
 928                                   GFP_NOFS);
 929                 unlock_extent(&BTRFS_I(inode)->io_tree,
 930                               start_pos, last_pos - 1, GFP_NOFS);
 931         }
 932         for (i = 0; i < num_pages; i++) {
 933                 clear_page_dirty_for_io(pages[i]);
 934                 set_page_extent_mapped(pages[i]);
 935                 WARN_ON(!PageLocked(pages[i]));
 936         }
 937         return 0;
 938 }
 939
 940 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
 941                                 size_t count, loff_t *ppos)
 942 {
 943         loff_t pos;
 944         loff_t start_pos;
 945         ssize_t num_written = 0;
 946         ssize_t err = 0;
 947         int ret = 0;
 948         struct inode *inode = fdentry(file)->d_inode;
 949         struct btrfs_root *root = BTRFS_I(inode)->root;
 950         struct page **pages = NULL;
 951         int nrptrs;
 952         struct page *pinned[2];
 953         unsigned long first_index;
 954         unsigned long last_index;
 955         int will_write;
 956
 957         will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) ||
 958                       (file->f_flags & O_DIRECT));
 959
 960         nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
 961                      PAGE_CACHE_SIZE / (sizeof(struct page *)));
 962         pinned[0] = NULL;
 963         pinned[1] = NULL;
 964
 965         pos = *ppos;
 966         start_pos = pos;
 967
 968         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
 969         current->backing_dev_info = inode->i_mapping->backing_dev_info;
 970         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
 971         if (err)
 972                 goto out_nolock;
 973         if (count == 0)
 974                 goto out_nolock;
 975
 976         err = file_remove_suid(file);
 977         if (err)
 978                 goto out_nolock;
 979         file_update_time(file);
 980
 981         pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
 982
 983         mutex_lock(&inode->i_mutex);
 984         BTRFS_I(inode)->sequence++;
 985         first_index = pos >> PAGE_CACHE_SHIFT;
 986         last_index = (pos + count) >> PAGE_CACHE_SHIFT;
 987
 988         /*
 989          * there are lots of better ways to do this, but this code
 990          * makes sure the first and last page in the file range are
 991          * up to date and ready for cow
 992          */
 993         if ((pos & (PAGE_CACHE_SIZE - 1))) {
 994                 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
 995                 if (!PageUptodate(pinned[0])) {
 996                         ret = btrfs_readpage(NULL, pinned[0]);
 997                         BUG_ON(ret);
 998                         wait_on_page_locked(pinned[0]);
 999                 } else {
1000                         unlock_page(pinned[0]);
1001                 }
1002         }
1003         if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
1004                 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
1005                 if (!PageUptodate(pinned[1])) {
1006                         ret = btrfs_readpage(NULL, pinned[1]);
1007                         BUG_ON(ret);
1008                         wait_on_page_locked(pinned[1]);
1009                 } else {
1010                         unlock_page(pinned[1]);
1011                 }
1012         }
1013
1014         while (count > 0) {
1015                 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1016                 size_t write_bytes = min(count, nrptrs *
1017                                         (size_t)PAGE_CACHE_SIZE -
1018                                          offset);
1019                 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
1020                                         PAGE_CACHE_SHIFT;
1021
1022                 WARN_ON(num_pages > nrptrs);
1023                 memset(pages, 0, sizeof(struct page *) * nrptrs);
1024
1025                 ret = btrfs_check_data_free_space(root, inode, write_bytes);
1026                 if (ret)
1027                         goto out;
1028
1029                 ret = prepare_pages(root, file, pages, num_pages,
1030                                     pos, first_index, last_index,
1031                                     write_bytes);
1032                 if (ret) {
1033                         btrfs_free_reserved_data_space(root, inode,
1034                                                        write_bytes);
1035                         goto out;
1036                 }
1037
1038                 ret = btrfs_copy_from_user(pos, num_pages,
1039                                            write_bytes, pages, buf);
1040                 if (ret) {
1041                         btrfs_free_reserved_data_space(root, inode,
1042                                                        write_bytes);
1043                         btrfs_drop_pages(pages, num_pages);
1044                         goto out;
1045                 }
1046
1047                 ret = dirty_and_release_pages(NULL, root, file, pages,
1048                                               num_pages, pos, write_bytes);
1049                 btrfs_drop_pages(pages, num_pages);
1050                 if (ret) {
1051                         btrfs_free_reserved_data_space(root, inode,
1052                                                        write_bytes);
1053                         goto out;
1054                 }
1055
1056                 if (will_write) {
1057                         btrfs_fdatawrite_range(inode->i_mapping, pos,
1058                                                pos + write_bytes - 1,
1059                                                WB_SYNC_ALL);
1060                 } else {
1061                         balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1062                                                            num_pages);
1063                         if (num_pages <
1064                             (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1065                                 btrfs_btree_balance_dirty(root, 1);
1066                         btrfs_throttle(root);
1067                 }
1068
1069                 buf += write_bytes;
1070                 count -= write_bytes;
1071                 pos += write_bytes;
1072                 num_written += write_bytes;
1073
1074                 cond_resched();
1075         }
1076 out:
1077         mutex_unlock(&inode->i_mutex);
1078         if (ret)
1079                 err = ret;
1080
1081 out_nolock:
1082         kfree(pages);
1083         if (pinned[0])
1084                 page_cache_release(pinned[0]);
1085         if (pinned[1])
1086                 page_cache_release(pinned[1]);
1087         *ppos = pos;
1088
1089         /*
1090          * we want to make sure fsync finds this change
1091          * but we haven't joined a transaction running right now.
1092          *
1093          * Later on, someone is sure to update the inode and get the
1094          * real transid recorded.
1095          *
1096          * We set last_trans now to the fs_info generation + 1,
1097          * this will either be one more than the running transaction
1098          * or the generation used for the next transaction if there isn't
1099          * one running right now.
1100          */
1101         BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1102
1103         if (num_written > 0 && will_write) {
1104                 struct btrfs_trans_handle *trans;
1105
1106                 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1107                 if (err)
1108                         num_written = err;
1109
1110                 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
1111                         trans = btrfs_start_transaction(root, 1);
1112                         ret = btrfs_log_dentry_safe(trans, root,
1113                                                     file->f_dentry);
1114                         if (ret == 0) {
1115                                 ret = btrfs_sync_log(trans, root);
1116                                 if (ret == 0)
1117                                         btrfs_end_transaction(trans, root);
1118                                 else
1119                                         btrfs_commit_transaction(trans, root);
1120                         } else {
1121                                 btrfs_commit_transaction(trans, root);
1122                         }
1123                 }
1124                 if (file->f_flags & O_DIRECT) {
1125                         invalidate_mapping_pages(inode->i_mapping,
1126                               start_pos >> PAGE_CACHE_SHIFT,
1127                              (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1128                 }
1129         }
1130         current->backing_dev_info = NULL;
1131         return num_written ? num_written : err;
1132 }
1133
1134 int btrfs_release_file(struct inode *inode, struct file *filp)
1135 {
1136         /*
1137          * ordered_data_close is set by settattr when we are about to truncate
1138          * a file from a non-zero size to a zero size.  This tries to
1139          * flush down new bytes that may have been written if the
1140          * application were using truncate to replace a file in place.
1141          */
1142         if (BTRFS_I(inode)->ordered_data_close) {
1143                 BTRFS_I(inode)->ordered_data_close = 0;
1144                 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1145                 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1146                         filemap_flush(inode->i_mapping);
1147         }
1148         if (filp->private_data)
1149                 btrfs_ioctl_trans_end(filp);
1150         return 0;
1151 }
1152
1153 /*
1154  * fsync call for both files and directories.  This logs the inode into
1155  * the tree log instead of forcing full commits whenever possible.
1156  *
1157  * It needs to call filemap_fdatawait so that all ordered extent updates are
1158  * in the metadata btree are up to date for copying to the log.
1159  *
1160  * It drops the inode mutex before doing the tree log commit.  This is an
1161  * important optimization for directories because holding the mutex prevents
1162  * new operations on the dir while we write to disk.
1163  */
1164 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
1165 {
1166         struct inode *inode = dentry->d_inode;
1167         struct btrfs_root *root = BTRFS_I(inode)->root;
1168         int ret = 0;
1169         struct btrfs_trans_handle *trans;
1170
1171         /*
1172          * check the transaction that last modified this inode
1173          * and see if its already been committed
1174          */
1175         if (!BTRFS_I(inode)->last_trans)
1176                 goto out;
1177
1178         mutex_lock(&root->fs_info->trans_mutex);
1179         if (BTRFS_I(inode)->last_trans <=
1180             root->fs_info->last_trans_committed) {
1181                 BTRFS_I(inode)->last_trans = 0;
1182                 mutex_unlock(&root->fs_info->trans_mutex);
1183                 goto out;
1184         }
1185         mutex_unlock(&root->fs_info->trans_mutex);
1186
1187         root->log_batch++;
1188         filemap_fdatawrite(inode->i_mapping);
1189         btrfs_wait_ordered_range(inode, 0, (u64)-1);
1190         root->log_batch++;
1191
1192         /*
1193          * ok we haven't committed the transaction yet, lets do a commit
1194          */
1195         if (file && file->private_data)
1196                 btrfs_ioctl_trans_end(file);
1197
1198         trans = btrfs_start_transaction(root, 1);
1199         if (!trans) {
1200                 ret = -ENOMEM;
1201                 goto out;
1202         }
1203
1204         ret = btrfs_log_dentry_safe(trans, root, dentry);
1205         if (ret < 0)
1206                 goto out;
1207
1208         /* we've logged all the items and now have a consistent
1209          * version of the file in the log.  It is possible that
1210          * someone will come in and modify the file, but that's
1211          * fine because the log is consistent on disk, and we
1212          * have references to all of the file's extents
1213          *
1214          * It is possible that someone will come in and log the
1215          * file again, but that will end up using the synchronization
1216          * inside btrfs_sync_log to keep things safe.
1217          */
1218         mutex_unlock(&dentry->d_inode->i_mutex);
1219
1220         if (ret > 0) {
1221                 ret = btrfs_commit_transaction(trans, root);
1222         } else {
1223                 ret = btrfs_sync_log(trans, root);
1224                 if (ret == 0)
1225                         ret = btrfs_end_transaction(trans, root);
1226                 else
1227                         ret = btrfs_commit_transaction(trans, root);
1228         }
1229         mutex_lock(&dentry->d_inode->i_mutex);
1230 out:
1231         return ret > 0 ? EIO : ret;
1232 }
1233
1234 static struct vm_operations_struct btrfs_file_vm_ops = {
1235         .fault          = filemap_fault,
1236         .page_mkwrite   = btrfs_page_mkwrite,
1237 };
1238
1239 static int btrfs_file_mmap(struct file  *filp, struct vm_area_struct *vma)
1240 {
1241         vma->vm_ops = &btrfs_file_vm_ops;
1242         file_accessed(filp);
1243         return 0;
1244 }
1245
1246 struct file_operations btrfs_file_operations = {
1247         .llseek         = generic_file_llseek,
1248         .read           = do_sync_read,
1249         .aio_read       = generic_file_aio_read,
1250         .splice_read    = generic_file_splice_read,
1251         .write          = btrfs_file_write,
1252         .mmap           = btrfs_file_mmap,
1253         .open           = generic_file_open,
1254         .release        = btrfs_release_file,
1255         .fsync          = btrfs_sync_file,
1256         .unlocked_ioctl = btrfs_ioctl,
1257 #ifdef CONFIG_COMPAT
1258         .compat_ioctl   = btrfs_ioctl,
1259 #endif
1260 };