Btrfs: add a priority queue to the async thread helpers
[linux-2.6.git] / 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 int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
276 {
277         return 0;
278 #if 0
279         struct btrfs_path *path;
280         struct btrfs_key found_key;
281         struct extent_buffer *leaf;
282         struct btrfs_file_extent_item *extent;
283         u64 last_offset = 0;
284         int nritems;
285         int slot;
286         int found_type;
287         int ret;
288         int err = 0;
289         u64 extent_end = 0;
290
291         path = btrfs_alloc_path();
292         ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
293                                        last_offset, 0);
294         while (1) {
295                 nritems = btrfs_header_nritems(path->nodes[0]);
296                 if (path->slots[0] >= nritems) {
297                         ret = btrfs_next_leaf(root, path);
298                         if (ret)
299                                 goto out;
300                         nritems = btrfs_header_nritems(path->nodes[0]);
301                 }
302                 slot = path->slots[0];
303                 leaf = path->nodes[0];
304                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
305                 if (found_key.objectid != inode->i_ino)
306                         break;
307                 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
308                         goto out;
309
310                 if (found_key.offset < last_offset) {
311                         WARN_ON(1);
312                         btrfs_print_leaf(root, leaf);
313                         printk(KERN_ERR "inode %lu found offset %llu "
314                                "expected %llu\n", inode->i_ino,
315                                (unsigned long long)found_key.offset,
316                                (unsigned long long)last_offset);
317                         err = 1;
318                         goto out;
319                 }
320                 extent = btrfs_item_ptr(leaf, slot,
321                                         struct btrfs_file_extent_item);
322                 found_type = btrfs_file_extent_type(leaf, extent);
323                 if (found_type == BTRFS_FILE_EXTENT_REG) {
324                         extent_end = found_key.offset +
325                              btrfs_file_extent_num_bytes(leaf, extent);
326                 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
327                         struct btrfs_item *item;
328                         item = btrfs_item_nr(leaf, slot);
329                         extent_end = found_key.offset +
330                              btrfs_file_extent_inline_len(leaf, extent);
331                         extent_end = (extent_end + root->sectorsize - 1) &
332                                 ~((u64)root->sectorsize - 1);
333                 }
334                 last_offset = extent_end;
335                 path->slots[0]++;
336         }
337         if (0 && last_offset < inode->i_size) {
338                 WARN_ON(1);
339                 btrfs_print_leaf(root, leaf);
340                 printk(KERN_ERR "inode %lu found offset %llu size %llu\n",
341                        inode->i_ino, (unsigned long long)last_offset,
342                        (unsigned long long)inode->i_size);
343                 err = 1;
344
345         }
346 out:
347         btrfs_free_path(path);
348         return err;
349 #endif
350 }
351
352 /*
353  * this is very complex, but the basic idea is to drop all extents
354  * in the range start - end.  hint_block is filled in with a block number
355  * that would be a good hint to the block allocator for this file.
356  *
357  * If an extent intersects the range but is not entirely inside the range
358  * it is either truncated or split.  Anything entirely inside the range
359  * is deleted from the tree.
360  *
361  * inline_limit is used to tell this code which offsets in the file to keep
362  * if they contain inline extents.
363  */
364 noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
365                        struct btrfs_root *root, struct inode *inode,
366                        u64 start, u64 end, u64 inline_limit, u64 *hint_byte)
367 {
368         u64 extent_end = 0;
369         u64 locked_end = end;
370         u64 search_start = start;
371         u64 leaf_start;
372         u64 ram_bytes = 0;
373         u64 orig_parent = 0;
374         u64 disk_bytenr = 0;
375         u8 compression;
376         u8 encryption;
377         u16 other_encoding = 0;
378         u64 root_gen;
379         u64 root_owner;
380         struct extent_buffer *leaf;
381         struct btrfs_file_extent_item *extent;
382         struct btrfs_path *path;
383         struct btrfs_key key;
384         struct btrfs_file_extent_item old;
385         int keep;
386         int slot;
387         int bookend;
388         int found_type = 0;
389         int found_extent;
390         int found_inline;
391         int recow;
392         int ret;
393
394         inline_limit = 0;
395         btrfs_drop_extent_cache(inode, start, end - 1, 0);
396
397         path = btrfs_alloc_path();
398         if (!path)
399                 return -ENOMEM;
400         while (1) {
401                 recow = 0;
402                 btrfs_release_path(root, path);
403                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
404                                                search_start, -1);
405                 if (ret < 0)
406                         goto out;
407                 if (ret > 0) {
408                         if (path->slots[0] == 0) {
409                                 ret = 0;
410                                 goto out;
411                         }
412                         path->slots[0]--;
413                 }
414 next_slot:
415                 keep = 0;
416                 bookend = 0;
417                 found_extent = 0;
418                 found_inline = 0;
419                 leaf_start = 0;
420                 root_gen = 0;
421                 root_owner = 0;
422                 compression = 0;
423                 encryption = 0;
424                 extent = NULL;
425                 leaf = path->nodes[0];
426                 slot = path->slots[0];
427                 ret = 0;
428                 btrfs_item_key_to_cpu(leaf, &key, slot);
429                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
430                     key.offset >= end) {
431                         goto out;
432                 }
433                 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
434                     key.objectid != inode->i_ino) {
435                         goto out;
436                 }
437                 if (recow) {
438                         search_start = max(key.offset, start);
439                         continue;
440                 }
441                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
442                         extent = btrfs_item_ptr(leaf, slot,
443                                                 struct btrfs_file_extent_item);
444                         found_type = btrfs_file_extent_type(leaf, extent);
445                         compression = btrfs_file_extent_compression(leaf,
446                                                                     extent);
447                         encryption = btrfs_file_extent_encryption(leaf,
448                                                                   extent);
449                         other_encoding = btrfs_file_extent_other_encoding(leaf,
450                                                                   extent);
451                         if (found_type == BTRFS_FILE_EXTENT_REG ||
452                             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
453                                 extent_end =
454                                      btrfs_file_extent_disk_bytenr(leaf,
455                                                                    extent);
456                                 if (extent_end)
457                                         *hint_byte = extent_end;
458
459                                 extent_end = key.offset +
460                                      btrfs_file_extent_num_bytes(leaf, extent);
461                                 ram_bytes = btrfs_file_extent_ram_bytes(leaf,
462                                                                 extent);
463                                 found_extent = 1;
464                         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
465                                 found_inline = 1;
466                                 extent_end = key.offset +
467                                      btrfs_file_extent_inline_len(leaf, extent);
468                         }
469                 } else {
470                         extent_end = search_start;
471                 }
472
473                 /* we found nothing we can drop */
474                 if ((!found_extent && !found_inline) ||
475                     search_start >= extent_end) {
476                         int nextret;
477                         u32 nritems;
478                         nritems = btrfs_header_nritems(leaf);
479                         if (slot >= nritems - 1) {
480                                 nextret = btrfs_next_leaf(root, path);
481                                 if (nextret)
482                                         goto out;
483                                 recow = 1;
484                         } else {
485                                 path->slots[0]++;
486                         }
487                         goto next_slot;
488                 }
489
490                 if (end <= extent_end && start >= key.offset && found_inline)
491                         *hint_byte = EXTENT_MAP_INLINE;
492
493                 if (found_extent) {
494                         read_extent_buffer(leaf, &old, (unsigned long)extent,
495                                            sizeof(old));
496                         root_gen = btrfs_header_generation(leaf);
497                         root_owner = btrfs_header_owner(leaf);
498                         leaf_start = leaf->start;
499                 }
500
501                 if (end < extent_end && end >= key.offset) {
502                         bookend = 1;
503                         if (found_inline && start <= key.offset)
504                                 keep = 1;
505                 }
506
507                 if (bookend && found_extent) {
508                         if (locked_end < extent_end) {
509                                 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
510                                                 locked_end, extent_end - 1,
511                                                 GFP_NOFS);
512                                 if (!ret) {
513                                         btrfs_release_path(root, path);
514                                         lock_extent(&BTRFS_I(inode)->io_tree,
515                                                 locked_end, extent_end - 1,
516                                                 GFP_NOFS);
517                                         locked_end = extent_end;
518                                         continue;
519                                 }
520                                 locked_end = extent_end;
521                         }
522                         orig_parent = path->nodes[0]->start;
523                         disk_bytenr = le64_to_cpu(old.disk_bytenr);
524                         if (disk_bytenr != 0) {
525                                 ret = btrfs_inc_extent_ref(trans, root,
526                                            disk_bytenr,
527                                            le64_to_cpu(old.disk_num_bytes),
528                                            orig_parent, root->root_key.objectid,
529                                            trans->transid, inode->i_ino);
530                                 BUG_ON(ret);
531                         }
532                 }
533
534                 if (found_inline) {
535                         u64 mask = root->sectorsize - 1;
536                         search_start = (extent_end + mask) & ~mask;
537                 } else
538                         search_start = extent_end;
539
540                 /* truncate existing extent */
541                 if (start > key.offset) {
542                         u64 new_num;
543                         u64 old_num;
544                         keep = 1;
545                         WARN_ON(start & (root->sectorsize - 1));
546                         if (found_extent) {
547                                 new_num = start - key.offset;
548                                 old_num = btrfs_file_extent_num_bytes(leaf,
549                                                                       extent);
550                                 *hint_byte =
551                                         btrfs_file_extent_disk_bytenr(leaf,
552                                                                       extent);
553                                 if (btrfs_file_extent_disk_bytenr(leaf,
554                                                                   extent)) {
555                                         inode_sub_bytes(inode, old_num -
556                                                         new_num);
557                                 }
558                                 btrfs_set_file_extent_num_bytes(leaf,
559                                                         extent, new_num);
560                                 btrfs_mark_buffer_dirty(leaf);
561                         } else if (key.offset < inline_limit &&
562                                    (end > extent_end) &&
563                                    (inline_limit < extent_end)) {
564                                 u32 new_size;
565                                 new_size = btrfs_file_extent_calc_inline_size(
566                                                    inline_limit - key.offset);
567                                 inode_sub_bytes(inode, extent_end -
568                                                 inline_limit);
569                                 btrfs_set_file_extent_ram_bytes(leaf, extent,
570                                                         new_size);
571                                 if (!compression && !encryption) {
572                                         btrfs_truncate_item(trans, root, path,
573                                                             new_size, 1);
574                                 }
575                         }
576                 }
577                 /* delete the entire extent */
578                 if (!keep) {
579                         if (found_inline)
580                                 inode_sub_bytes(inode, extent_end -
581                                                 key.offset);
582                         ret = btrfs_del_item(trans, root, path);
583                         /* TODO update progress marker and return */
584                         BUG_ON(ret);
585                         extent = NULL;
586                         btrfs_release_path(root, path);
587                         /* the extent will be freed later */
588                 }
589                 if (bookend && found_inline && start <= key.offset) {
590                         u32 new_size;
591                         new_size = btrfs_file_extent_calc_inline_size(
592                                                    extent_end - end);
593                         inode_sub_bytes(inode, end - key.offset);
594                         btrfs_set_file_extent_ram_bytes(leaf, extent,
595                                                         new_size);
596                         if (!compression && !encryption)
597                                 ret = btrfs_truncate_item(trans, root, path,
598                                                           new_size, 0);
599                         BUG_ON(ret);
600                 }
601                 /* create bookend, splitting the extent in two */
602                 if (bookend && found_extent) {
603                         struct btrfs_key ins;
604                         ins.objectid = inode->i_ino;
605                         ins.offset = end;
606                         btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
607
608                         btrfs_release_path(root, path);
609                         path->leave_spinning = 1;
610                         ret = btrfs_insert_empty_item(trans, root, path, &ins,
611                                                       sizeof(*extent));
612                         BUG_ON(ret);
613
614                         leaf = path->nodes[0];
615                         extent = btrfs_item_ptr(leaf, path->slots[0],
616                                                 struct btrfs_file_extent_item);
617                         write_extent_buffer(leaf, &old,
618                                             (unsigned long)extent, sizeof(old));
619
620                         btrfs_set_file_extent_compression(leaf, extent,
621                                                           compression);
622                         btrfs_set_file_extent_encryption(leaf, extent,
623                                                          encryption);
624                         btrfs_set_file_extent_other_encoding(leaf, extent,
625                                                              other_encoding);
626                         btrfs_set_file_extent_offset(leaf, extent,
627                                     le64_to_cpu(old.offset) + end - key.offset);
628                         WARN_ON(le64_to_cpu(old.num_bytes) <
629                                 (extent_end - end));
630                         btrfs_set_file_extent_num_bytes(leaf, extent,
631                                                         extent_end - end);
632
633                         /*
634                          * set the ram bytes to the size of the full extent
635                          * before splitting.  This is a worst case flag,
636                          * but its the best we can do because we don't know
637                          * how splitting affects compression
638                          */
639                         btrfs_set_file_extent_ram_bytes(leaf, extent,
640                                                         ram_bytes);
641                         btrfs_set_file_extent_type(leaf, extent, found_type);
642
643                         btrfs_unlock_up_safe(path, 1);
644                         btrfs_mark_buffer_dirty(path->nodes[0]);
645                         btrfs_set_lock_blocking(path->nodes[0]);
646
647                         if (disk_bytenr != 0) {
648                                 ret = btrfs_update_extent_ref(trans, root,
649                                                 disk_bytenr,
650                                                 le64_to_cpu(old.disk_num_bytes),
651                                                 orig_parent,
652                                                 leaf->start,
653                                                 root->root_key.objectid,
654                                                 trans->transid, ins.objectid);
655
656                                 BUG_ON(ret);
657                         }
658                         path->leave_spinning = 0;
659                         btrfs_release_path(root, path);
660                         if (disk_bytenr != 0)
661                                 inode_add_bytes(inode, extent_end - end);
662                 }
663
664                 if (found_extent && !keep) {
665                         u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr);
666
667                         if (old_disk_bytenr != 0) {
668                                 inode_sub_bytes(inode,
669                                                 le64_to_cpu(old.num_bytes));
670                                 ret = btrfs_free_extent(trans, root,
671                                                 old_disk_bytenr,
672                                                 le64_to_cpu(old.disk_num_bytes),
673                                                 leaf_start, root_owner,
674                                                 root_gen, key.objectid, 0);
675                                 BUG_ON(ret);
676                                 *hint_byte = old_disk_bytenr;
677                         }
678                 }
679
680                 if (search_start >= end) {
681                         ret = 0;
682                         goto out;
683                 }
684         }
685 out:
686         btrfs_free_path(path);
687         if (locked_end > end) {
688                 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
689                               GFP_NOFS);
690         }
691         btrfs_check_file(root, inode);
692         return ret;
693 }
694
695 static int extent_mergeable(struct extent_buffer *leaf, int slot,
696                             u64 objectid, u64 bytenr, u64 *start, u64 *end)
697 {
698         struct btrfs_file_extent_item *fi;
699         struct btrfs_key key;
700         u64 extent_end;
701
702         if (slot < 0 || slot >= btrfs_header_nritems(leaf))
703                 return 0;
704
705         btrfs_item_key_to_cpu(leaf, &key, slot);
706         if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
707                 return 0;
708
709         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
710         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
711             btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
712             btrfs_file_extent_compression(leaf, fi) ||
713             btrfs_file_extent_encryption(leaf, fi) ||
714             btrfs_file_extent_other_encoding(leaf, fi))
715                 return 0;
716
717         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
718         if ((*start && *start != key.offset) || (*end && *end != extent_end))
719                 return 0;
720
721         *start = key.offset;
722         *end = extent_end;
723         return 1;
724 }
725
726 /*
727  * Mark extent in the range start - end as written.
728  *
729  * This changes extent type from 'pre-allocated' to 'regular'. If only
730  * part of extent is marked as written, the extent will be split into
731  * two or three.
732  */
733 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
734                               struct btrfs_root *root,
735                               struct inode *inode, u64 start, u64 end)
736 {
737         struct extent_buffer *leaf;
738         struct btrfs_path *path;
739         struct btrfs_file_extent_item *fi;
740         struct btrfs_key key;
741         u64 bytenr;
742         u64 num_bytes;
743         u64 extent_end;
744         u64 extent_offset;
745         u64 other_start;
746         u64 other_end;
747         u64 split = start;
748         u64 locked_end = end;
749         u64 orig_parent;
750         int extent_type;
751         int split_end = 1;
752         int ret;
753
754         btrfs_drop_extent_cache(inode, start, end - 1, 0);
755
756         path = btrfs_alloc_path();
757         BUG_ON(!path);
758 again:
759         key.objectid = inode->i_ino;
760         key.type = BTRFS_EXTENT_DATA_KEY;
761         if (split == start)
762                 key.offset = split;
763         else
764                 key.offset = split - 1;
765
766         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
767         if (ret > 0 && path->slots[0] > 0)
768                 path->slots[0]--;
769
770         leaf = path->nodes[0];
771         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
772         BUG_ON(key.objectid != inode->i_ino ||
773                key.type != BTRFS_EXTENT_DATA_KEY);
774         fi = btrfs_item_ptr(leaf, path->slots[0],
775                             struct btrfs_file_extent_item);
776         extent_type = btrfs_file_extent_type(leaf, fi);
777         BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC);
778         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
779         BUG_ON(key.offset > start || extent_end < end);
780
781         bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
782         num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
783         extent_offset = btrfs_file_extent_offset(leaf, fi);
784
785         if (key.offset == start)
786                 split = end;
787
788         if (key.offset == start && extent_end == end) {
789                 int del_nr = 0;
790                 int del_slot = 0;
791                 u64 leaf_owner = btrfs_header_owner(leaf);
792                 u64 leaf_gen = btrfs_header_generation(leaf);
793                 other_start = end;
794                 other_end = 0;
795                 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
796                                      bytenr, &other_start, &other_end)) {
797                         extent_end = other_end;
798                         del_slot = path->slots[0] + 1;
799                         del_nr++;
800                         ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
801                                                 leaf->start, leaf_owner,
802                                                 leaf_gen, inode->i_ino, 0);
803                         BUG_ON(ret);
804                 }
805                 other_start = 0;
806                 other_end = start;
807                 if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino,
808                                      bytenr, &other_start, &other_end)) {
809                         key.offset = other_start;
810                         del_slot = path->slots[0];
811                         del_nr++;
812                         ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
813                                                 leaf->start, leaf_owner,
814                                                 leaf_gen, inode->i_ino, 0);
815                         BUG_ON(ret);
816                 }
817                 split_end = 0;
818                 if (del_nr == 0) {
819                         btrfs_set_file_extent_type(leaf, fi,
820                                                    BTRFS_FILE_EXTENT_REG);
821                         goto done;
822                 }
823
824                 fi = btrfs_item_ptr(leaf, del_slot - 1,
825                                     struct btrfs_file_extent_item);
826                 btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
827                 btrfs_set_file_extent_num_bytes(leaf, fi,
828                                                 extent_end - key.offset);
829                 btrfs_mark_buffer_dirty(leaf);
830
831                 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
832                 BUG_ON(ret);
833                 goto done;
834         } else if (split == start) {
835                 if (locked_end < extent_end) {
836                         ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
837                                         locked_end, extent_end - 1, GFP_NOFS);
838                         if (!ret) {
839                                 btrfs_release_path(root, path);
840                                 lock_extent(&BTRFS_I(inode)->io_tree,
841                                         locked_end, extent_end - 1, GFP_NOFS);
842                                 locked_end = extent_end;
843                                 goto again;
844                         }
845                         locked_end = extent_end;
846                 }
847                 btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
848                 extent_offset += split - key.offset;
849         } else  {
850                 BUG_ON(key.offset != start);
851                 btrfs_set_file_extent_offset(leaf, fi, extent_offset +
852                                              split - key.offset);
853                 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
854                 key.offset = split;
855                 btrfs_set_item_key_safe(trans, root, path, &key);
856                 extent_end = split;
857         }
858
859         if (extent_end == end) {
860                 split_end = 0;
861                 extent_type = BTRFS_FILE_EXTENT_REG;
862         }
863         if (extent_end == end && split == start) {
864                 other_start = end;
865                 other_end = 0;
866                 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
867                                      bytenr, &other_start, &other_end)) {
868                         path->slots[0]++;
869                         fi = btrfs_item_ptr(leaf, path->slots[0],
870                                             struct btrfs_file_extent_item);
871                         key.offset = split;
872                         btrfs_set_item_key_safe(trans, root, path, &key);
873                         btrfs_set_file_extent_offset(leaf, fi, extent_offset);
874                         btrfs_set_file_extent_num_bytes(leaf, fi,
875                                                         other_end - split);
876                         goto done;
877                 }
878         }
879         if (extent_end == end && split == end) {
880                 other_start = 0;
881                 other_end = start;
882                 if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino,
883                                      bytenr, &other_start, &other_end)) {
884                         path->slots[0]--;
885                         fi = btrfs_item_ptr(leaf, path->slots[0],
886                                             struct btrfs_file_extent_item);
887                         btrfs_set_file_extent_num_bytes(leaf, fi, extent_end -
888                                                         other_start);
889                         goto done;
890                 }
891         }
892
893         btrfs_mark_buffer_dirty(leaf);
894
895         orig_parent = leaf->start;
896         ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
897                                    orig_parent, root->root_key.objectid,
898                                    trans->transid, inode->i_ino);
899         BUG_ON(ret);
900         btrfs_release_path(root, path);
901
902         key.offset = start;
903         ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi));
904         BUG_ON(ret);
905
906         leaf = path->nodes[0];
907         fi = btrfs_item_ptr(leaf, path->slots[0],
908                             struct btrfs_file_extent_item);
909         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
910         btrfs_set_file_extent_type(leaf, fi, extent_type);
911         btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr);
912         btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
913         btrfs_set_file_extent_offset(leaf, fi, extent_offset);
914         btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset);
915         btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
916         btrfs_set_file_extent_compression(leaf, fi, 0);
917         btrfs_set_file_extent_encryption(leaf, fi, 0);
918         btrfs_set_file_extent_other_encoding(leaf, fi, 0);
919
920         if (orig_parent != leaf->start) {
921                 ret = btrfs_update_extent_ref(trans, root, bytenr, num_bytes,
922                                               orig_parent, leaf->start,
923                                               root->root_key.objectid,
924                                               trans->transid, inode->i_ino);
925                 BUG_ON(ret);
926         }
927 done:
928         btrfs_mark_buffer_dirty(leaf);
929         btrfs_release_path(root, path);
930         if (split_end && split == start) {
931                 split = end;
932                 goto again;
933         }
934         if (locked_end > end) {
935                 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
936                               GFP_NOFS);
937         }
938         btrfs_free_path(path);
939         return 0;
940 }
941
942 /*
943  * this gets pages into the page cache and locks them down, it also properly
944  * waits for data=ordered extents to finish before allowing the pages to be
945  * modified.
946  */
947 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
948                          struct page **pages, size_t num_pages,
949                          loff_t pos, unsigned long first_index,
950                          unsigned long last_index, size_t write_bytes)
951 {
952         int i;
953         unsigned long index = pos >> PAGE_CACHE_SHIFT;
954         struct inode *inode = fdentry(file)->d_inode;
955         int err = 0;
956         u64 start_pos;
957         u64 last_pos;
958
959         start_pos = pos & ~((u64)root->sectorsize - 1);
960         last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
961
962         if (start_pos > inode->i_size) {
963                 err = btrfs_cont_expand(inode, start_pos);
964                 if (err)
965                         return err;
966         }
967
968         memset(pages, 0, num_pages * sizeof(struct page *));
969 again:
970         for (i = 0; i < num_pages; i++) {
971                 pages[i] = grab_cache_page(inode->i_mapping, index + i);
972                 if (!pages[i]) {
973                         err = -ENOMEM;
974                         BUG_ON(1);
975                 }
976                 wait_on_page_writeback(pages[i]);
977         }
978         if (start_pos < inode->i_size) {
979                 struct btrfs_ordered_extent *ordered;
980                 lock_extent(&BTRFS_I(inode)->io_tree,
981                             start_pos, last_pos - 1, GFP_NOFS);
982                 ordered = btrfs_lookup_first_ordered_extent(inode,
983                                                             last_pos - 1);
984                 if (ordered &&
985                     ordered->file_offset + ordered->len > start_pos &&
986                     ordered->file_offset < last_pos) {
987                         btrfs_put_ordered_extent(ordered);
988                         unlock_extent(&BTRFS_I(inode)->io_tree,
989                                       start_pos, last_pos - 1, GFP_NOFS);
990                         for (i = 0; i < num_pages; i++) {
991                                 unlock_page(pages[i]);
992                                 page_cache_release(pages[i]);
993                         }
994                         btrfs_wait_ordered_range(inode, start_pos,
995                                                  last_pos - start_pos);
996                         goto again;
997                 }
998                 if (ordered)
999                         btrfs_put_ordered_extent(ordered);
1000
1001                 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
1002                                   last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
1003                                   GFP_NOFS);
1004                 unlock_extent(&BTRFS_I(inode)->io_tree,
1005                               start_pos, last_pos - 1, GFP_NOFS);
1006         }
1007         for (i = 0; i < num_pages; i++) {
1008                 clear_page_dirty_for_io(pages[i]);
1009                 set_page_extent_mapped(pages[i]);
1010                 WARN_ON(!PageLocked(pages[i]));
1011         }
1012         return 0;
1013 }
1014
1015 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
1016                                 size_t count, loff_t *ppos)
1017 {
1018         loff_t pos;
1019         loff_t start_pos;
1020         ssize_t num_written = 0;
1021         ssize_t err = 0;
1022         int ret = 0;
1023         struct inode *inode = fdentry(file)->d_inode;
1024         struct btrfs_root *root = BTRFS_I(inode)->root;
1025         struct page **pages = NULL;
1026         int nrptrs;
1027         struct page *pinned[2];
1028         unsigned long first_index;
1029         unsigned long last_index;
1030         int will_write;
1031
1032         will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) ||
1033                       (file->f_flags & O_DIRECT));
1034
1035         nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
1036                      PAGE_CACHE_SIZE / (sizeof(struct page *)));
1037         pinned[0] = NULL;
1038         pinned[1] = NULL;
1039
1040         pos = *ppos;
1041         start_pos = pos;
1042
1043         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
1044         current->backing_dev_info = inode->i_mapping->backing_dev_info;
1045         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1046         if (err)
1047                 goto out_nolock;
1048         if (count == 0)
1049                 goto out_nolock;
1050
1051         err = file_remove_suid(file);
1052         if (err)
1053                 goto out_nolock;
1054         file_update_time(file);
1055
1056         pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1057
1058         mutex_lock(&inode->i_mutex);
1059         BTRFS_I(inode)->sequence++;
1060         first_index = pos >> PAGE_CACHE_SHIFT;
1061         last_index = (pos + count) >> PAGE_CACHE_SHIFT;
1062
1063         /*
1064          * there are lots of better ways to do this, but this code
1065          * makes sure the first and last page in the file range are
1066          * up to date and ready for cow
1067          */
1068         if ((pos & (PAGE_CACHE_SIZE - 1))) {
1069                 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
1070                 if (!PageUptodate(pinned[0])) {
1071                         ret = btrfs_readpage(NULL, pinned[0]);
1072                         BUG_ON(ret);
1073                         wait_on_page_locked(pinned[0]);
1074                 } else {
1075                         unlock_page(pinned[0]);
1076                 }
1077         }
1078         if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
1079                 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
1080                 if (!PageUptodate(pinned[1])) {
1081                         ret = btrfs_readpage(NULL, pinned[1]);
1082                         BUG_ON(ret);
1083                         wait_on_page_locked(pinned[1]);
1084                 } else {
1085                         unlock_page(pinned[1]);
1086                 }
1087         }
1088
1089         while (count > 0) {
1090                 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1091                 size_t write_bytes = min(count, nrptrs *
1092                                         (size_t)PAGE_CACHE_SIZE -
1093                                          offset);
1094                 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
1095                                         PAGE_CACHE_SHIFT;
1096
1097                 WARN_ON(num_pages > nrptrs);
1098                 memset(pages, 0, sizeof(struct page *) * nrptrs);
1099
1100                 ret = btrfs_check_data_free_space(root, inode, write_bytes);
1101                 if (ret)
1102                         goto out;
1103
1104                 ret = prepare_pages(root, file, pages, num_pages,
1105                                     pos, first_index, last_index,
1106                                     write_bytes);
1107                 if (ret) {
1108                         btrfs_free_reserved_data_space(root, inode,
1109                                                        write_bytes);
1110                         goto out;
1111                 }
1112
1113                 ret = btrfs_copy_from_user(pos, num_pages,
1114                                            write_bytes, pages, buf);
1115                 if (ret) {
1116                         btrfs_free_reserved_data_space(root, inode,
1117                                                        write_bytes);
1118                         btrfs_drop_pages(pages, num_pages);
1119                         goto out;
1120                 }
1121
1122                 ret = dirty_and_release_pages(NULL, root, file, pages,
1123                                               num_pages, pos, write_bytes);
1124                 btrfs_drop_pages(pages, num_pages);
1125                 if (ret) {
1126                         btrfs_free_reserved_data_space(root, inode,
1127                                                        write_bytes);
1128                         goto out;
1129                 }
1130
1131                 if (will_write) {
1132                         btrfs_fdatawrite_range(inode->i_mapping, pos,
1133                                                pos + write_bytes - 1,
1134                                                WB_SYNC_ALL);
1135                 } else {
1136                         balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1137                                                            num_pages);
1138                         if (num_pages <
1139                             (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1140                                 btrfs_btree_balance_dirty(root, 1);
1141                         btrfs_throttle(root);
1142                 }
1143
1144                 buf += write_bytes;
1145                 count -= write_bytes;
1146                 pos += write_bytes;
1147                 num_written += write_bytes;
1148
1149                 cond_resched();
1150         }
1151 out:
1152         mutex_unlock(&inode->i_mutex);
1153         if (ret)
1154                 err = ret;
1155
1156 out_nolock:
1157         kfree(pages);
1158         if (pinned[0])
1159                 page_cache_release(pinned[0]);
1160         if (pinned[1])
1161                 page_cache_release(pinned[1]);
1162         *ppos = pos;
1163
1164         /*
1165          * we want to make sure fsync finds this change
1166          * but we haven't joined a transaction running right now.
1167          *
1168          * Later on, someone is sure to update the inode and get the
1169          * real transid recorded.
1170          *
1171          * We set last_trans now to the fs_info generation + 1,
1172          * this will either be one more than the running transaction
1173          * or the generation used for the next transaction if there isn't
1174          * one running right now.
1175          */
1176         BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1177
1178         if (num_written > 0 && will_write) {
1179                 struct btrfs_trans_handle *trans;
1180
1181                 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1182                 if (err)
1183                         num_written = err;
1184
1185                 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
1186                         trans = btrfs_start_transaction(root, 1);
1187                         ret = btrfs_log_dentry_safe(trans, root,
1188                                                     file->f_dentry);
1189                         if (ret == 0) {
1190                                 ret = btrfs_sync_log(trans, root);
1191                                 if (ret == 0)
1192                                         btrfs_end_transaction(trans, root);
1193                                 else
1194                                         btrfs_commit_transaction(trans, root);
1195                         } else {
1196                                 btrfs_commit_transaction(trans, root);
1197                         }
1198                 }
1199                 if (file->f_flags & O_DIRECT) {
1200                         invalidate_mapping_pages(inode->i_mapping,
1201                               start_pos >> PAGE_CACHE_SHIFT,
1202                              (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1203                 }
1204         }
1205         current->backing_dev_info = NULL;
1206         return num_written ? num_written : err;
1207 }
1208
1209 int btrfs_release_file(struct inode *inode, struct file *filp)
1210 {
1211         /*
1212          * ordered_data_close is set by settattr when we are about to truncate
1213          * a file from a non-zero size to a zero size.  This tries to
1214          * flush down new bytes that may have been written if the
1215          * application were using truncate to replace a file in place.
1216          */
1217         if (BTRFS_I(inode)->ordered_data_close) {
1218                 BTRFS_I(inode)->ordered_data_close = 0;
1219                 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1220                 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1221                         filemap_flush(inode->i_mapping);
1222         }
1223         if (filp->private_data)
1224                 btrfs_ioctl_trans_end(filp);
1225         return 0;
1226 }
1227
1228 /*
1229  * fsync call for both files and directories.  This logs the inode into
1230  * the tree log instead of forcing full commits whenever possible.
1231  *
1232  * It needs to call filemap_fdatawait so that all ordered extent updates are
1233  * in the metadata btree are up to date for copying to the log.
1234  *
1235  * It drops the inode mutex before doing the tree log commit.  This is an
1236  * important optimization for directories because holding the mutex prevents
1237  * new operations on the dir while we write to disk.
1238  */
1239 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
1240 {
1241         struct inode *inode = dentry->d_inode;
1242         struct btrfs_root *root = BTRFS_I(inode)->root;
1243         int ret = 0;
1244         struct btrfs_trans_handle *trans;
1245
1246         /*
1247          * check the transaction that last modified this inode
1248          * and see if its already been committed
1249          */
1250         if (!BTRFS_I(inode)->last_trans)
1251                 goto out;
1252
1253         mutex_lock(&root->fs_info->trans_mutex);
1254         if (BTRFS_I(inode)->last_trans <=
1255             root->fs_info->last_trans_committed) {
1256                 BTRFS_I(inode)->last_trans = 0;
1257                 mutex_unlock(&root->fs_info->trans_mutex);
1258                 goto out;
1259         }
1260         mutex_unlock(&root->fs_info->trans_mutex);
1261
1262         root->log_batch++;
1263         filemap_fdatawrite(inode->i_mapping);
1264         btrfs_wait_ordered_range(inode, 0, (u64)-1);
1265         root->log_batch++;
1266
1267         /*
1268          * ok we haven't committed the transaction yet, lets do a commit
1269          */
1270         if (file && file->private_data)
1271                 btrfs_ioctl_trans_end(file);
1272
1273         trans = btrfs_start_transaction(root, 1);
1274         if (!trans) {
1275                 ret = -ENOMEM;
1276                 goto out;
1277         }
1278
1279         ret = btrfs_log_dentry_safe(trans, root, dentry);
1280         if (ret < 0)
1281                 goto out;
1282
1283         /* we've logged all the items and now have a consistent
1284          * version of the file in the log.  It is possible that
1285          * someone will come in and modify the file, but that's
1286          * fine because the log is consistent on disk, and we
1287          * have references to all of the file's extents
1288          *
1289          * It is possible that someone will come in and log the
1290          * file again, but that will end up using the synchronization
1291          * inside btrfs_sync_log to keep things safe.
1292          */
1293         mutex_unlock(&dentry->d_inode->i_mutex);
1294
1295         if (ret > 0) {
1296                 ret = btrfs_commit_transaction(trans, root);
1297         } else {
1298                 ret = btrfs_sync_log(trans, root);
1299                 if (ret == 0)
1300                         ret = btrfs_end_transaction(trans, root);
1301                 else
1302                         ret = btrfs_commit_transaction(trans, root);
1303         }
1304         mutex_lock(&dentry->d_inode->i_mutex);
1305 out:
1306         return ret > 0 ? EIO : ret;
1307 }
1308
1309 static struct vm_operations_struct btrfs_file_vm_ops = {
1310         .fault          = filemap_fault,
1311         .page_mkwrite   = btrfs_page_mkwrite,
1312 };
1313
1314 static int btrfs_file_mmap(struct file  *filp, struct vm_area_struct *vma)
1315 {
1316         vma->vm_ops = &btrfs_file_vm_ops;
1317         file_accessed(filp);
1318         return 0;
1319 }
1320
1321 struct file_operations btrfs_file_operations = {
1322         .llseek         = generic_file_llseek,
1323         .read           = do_sync_read,
1324         .aio_read       = generic_file_aio_read,
1325         .splice_read    = generic_file_splice_read,
1326         .write          = btrfs_file_write,
1327         .mmap           = btrfs_file_mmap,
1328         .open           = generic_file_open,
1329         .release        = btrfs_release_file,
1330         .fsync          = btrfs_sync_file,
1331         .unlocked_ioctl = btrfs_ioctl,
1332 #ifdef CONFIG_COMPAT
1333         .compat_ioctl   = btrfs_ioctl,
1334 #endif
1335 };