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Merge commit 'c104f1fa1ecf4ee0fc06e31b1f77630b2551be81' into stable/for-linus-3.4
[deliverable/linux.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/backing-dev.h>
26 #include <linux/mpage.h>
27 #include <linux/falloc.h>
28 #include <linux/swap.h>
29 #include <linux/writeback.h>
30 #include <linux/statfs.h>
31 #include <linux/compat.h>
32 #include <linux/slab.h>
33 #include "ctree.h"
34 #include "disk-io.h"
35 #include "transaction.h"
36 #include "btrfs_inode.h"
37 #include "ioctl.h"
38 #include "print-tree.h"
39 #include "tree-log.h"
40 #include "locking.h"
41 #include "compat.h"
42
43 /*
44 * when auto defrag is enabled we
45 * queue up these defrag structs to remember which
46 * inodes need defragging passes
47 */
48 struct inode_defrag {
49 struct rb_node rb_node;
50 /* objectid */
51 u64 ino;
52 /*
53 * transid where the defrag was added, we search for
54 * extents newer than this
55 */
56 u64 transid;
57
58 /* root objectid */
59 u64 root;
60
61 /* last offset we were able to defrag */
62 u64 last_offset;
63
64 /* if we've wrapped around back to zero once already */
65 int cycled;
66 };
67
68 /* pop a record for an inode into the defrag tree. The lock
69 * must be held already
70 *
71 * If you're inserting a record for an older transid than an
72 * existing record, the transid already in the tree is lowered
73 *
74 * If an existing record is found the defrag item you
75 * pass in is freed
76 */
77 static void __btrfs_add_inode_defrag(struct inode *inode,
78 struct inode_defrag *defrag)
79 {
80 struct btrfs_root *root = BTRFS_I(inode)->root;
81 struct inode_defrag *entry;
82 struct rb_node **p;
83 struct rb_node *parent = NULL;
84
85 p = &root->fs_info->defrag_inodes.rb_node;
86 while (*p) {
87 parent = *p;
88 entry = rb_entry(parent, struct inode_defrag, rb_node);
89
90 if (defrag->ino < entry->ino)
91 p = &parent->rb_left;
92 else if (defrag->ino > entry->ino)
93 p = &parent->rb_right;
94 else {
95 /* if we're reinserting an entry for
96 * an old defrag run, make sure to
97 * lower the transid of our existing record
98 */
99 if (defrag->transid < entry->transid)
100 entry->transid = defrag->transid;
101 if (defrag->last_offset > entry->last_offset)
102 entry->last_offset = defrag->last_offset;
103 goto exists;
104 }
105 }
106 BTRFS_I(inode)->in_defrag = 1;
107 rb_link_node(&defrag->rb_node, parent, p);
108 rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes);
109 return;
110
111 exists:
112 kfree(defrag);
113 return;
114
115 }
116
117 /*
118 * insert a defrag record for this inode if auto defrag is
119 * enabled
120 */
121 int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
122 struct inode *inode)
123 {
124 struct btrfs_root *root = BTRFS_I(inode)->root;
125 struct inode_defrag *defrag;
126 u64 transid;
127
128 if (!btrfs_test_opt(root, AUTO_DEFRAG))
129 return 0;
130
131 if (btrfs_fs_closing(root->fs_info))
132 return 0;
133
134 if (BTRFS_I(inode)->in_defrag)
135 return 0;
136
137 if (trans)
138 transid = trans->transid;
139 else
140 transid = BTRFS_I(inode)->root->last_trans;
141
142 defrag = kzalloc(sizeof(*defrag), GFP_NOFS);
143 if (!defrag)
144 return -ENOMEM;
145
146 defrag->ino = btrfs_ino(inode);
147 defrag->transid = transid;
148 defrag->root = root->root_key.objectid;
149
150 spin_lock(&root->fs_info->defrag_inodes_lock);
151 if (!BTRFS_I(inode)->in_defrag)
152 __btrfs_add_inode_defrag(inode, defrag);
153 else
154 kfree(defrag);
155 spin_unlock(&root->fs_info->defrag_inodes_lock);
156 return 0;
157 }
158
159 /*
160 * must be called with the defrag_inodes lock held
161 */
162 struct inode_defrag *btrfs_find_defrag_inode(struct btrfs_fs_info *info, u64 ino,
163 struct rb_node **next)
164 {
165 struct inode_defrag *entry = NULL;
166 struct rb_node *p;
167 struct rb_node *parent = NULL;
168
169 p = info->defrag_inodes.rb_node;
170 while (p) {
171 parent = p;
172 entry = rb_entry(parent, struct inode_defrag, rb_node);
173
174 if (ino < entry->ino)
175 p = parent->rb_left;
176 else if (ino > entry->ino)
177 p = parent->rb_right;
178 else
179 return entry;
180 }
181
182 if (next) {
183 while (parent && ino > entry->ino) {
184 parent = rb_next(parent);
185 entry = rb_entry(parent, struct inode_defrag, rb_node);
186 }
187 *next = parent;
188 }
189 return NULL;
190 }
191
192 /*
193 * run through the list of inodes in the FS that need
194 * defragging
195 */
196 int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
197 {
198 struct inode_defrag *defrag;
199 struct btrfs_root *inode_root;
200 struct inode *inode;
201 struct rb_node *n;
202 struct btrfs_key key;
203 struct btrfs_ioctl_defrag_range_args range;
204 u64 first_ino = 0;
205 int num_defrag;
206 int defrag_batch = 1024;
207
208 memset(&range, 0, sizeof(range));
209 range.len = (u64)-1;
210
211 atomic_inc(&fs_info->defrag_running);
212 spin_lock(&fs_info->defrag_inodes_lock);
213 while(1) {
214 n = NULL;
215
216 /* find an inode to defrag */
217 defrag = btrfs_find_defrag_inode(fs_info, first_ino, &n);
218 if (!defrag) {
219 if (n)
220 defrag = rb_entry(n, struct inode_defrag, rb_node);
221 else if (first_ino) {
222 first_ino = 0;
223 continue;
224 } else {
225 break;
226 }
227 }
228
229 /* remove it from the rbtree */
230 first_ino = defrag->ino + 1;
231 rb_erase(&defrag->rb_node, &fs_info->defrag_inodes);
232
233 if (btrfs_fs_closing(fs_info))
234 goto next_free;
235
236 spin_unlock(&fs_info->defrag_inodes_lock);
237
238 /* get the inode */
239 key.objectid = defrag->root;
240 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
241 key.offset = (u64)-1;
242 inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
243 if (IS_ERR(inode_root))
244 goto next;
245
246 key.objectid = defrag->ino;
247 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
248 key.offset = 0;
249
250 inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
251 if (IS_ERR(inode))
252 goto next;
253
254 /* do a chunk of defrag */
255 BTRFS_I(inode)->in_defrag = 0;
256 range.start = defrag->last_offset;
257 num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
258 defrag_batch);
259 /*
260 * if we filled the whole defrag batch, there
261 * must be more work to do. Queue this defrag
262 * again
263 */
264 if (num_defrag == defrag_batch) {
265 defrag->last_offset = range.start;
266 __btrfs_add_inode_defrag(inode, defrag);
267 /*
268 * we don't want to kfree defrag, we added it back to
269 * the rbtree
270 */
271 defrag = NULL;
272 } else if (defrag->last_offset && !defrag->cycled) {
273 /*
274 * we didn't fill our defrag batch, but
275 * we didn't start at zero. Make sure we loop
276 * around to the start of the file.
277 */
278 defrag->last_offset = 0;
279 defrag->cycled = 1;
280 __btrfs_add_inode_defrag(inode, defrag);
281 defrag = NULL;
282 }
283
284 iput(inode);
285 next:
286 spin_lock(&fs_info->defrag_inodes_lock);
287 next_free:
288 kfree(defrag);
289 }
290 spin_unlock(&fs_info->defrag_inodes_lock);
291
292 atomic_dec(&fs_info->defrag_running);
293
294 /*
295 * during unmount, we use the transaction_wait queue to
296 * wait for the defragger to stop
297 */
298 wake_up(&fs_info->transaction_wait);
299 return 0;
300 }
301
302 /* simple helper to fault in pages and copy. This should go away
303 * and be replaced with calls into generic code.
304 */
305 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
306 size_t write_bytes,
307 struct page **prepared_pages,
308 struct iov_iter *i)
309 {
310 size_t copied = 0;
311 size_t total_copied = 0;
312 int pg = 0;
313 int offset = pos & (PAGE_CACHE_SIZE - 1);
314
315 while (write_bytes > 0) {
316 size_t count = min_t(size_t,
317 PAGE_CACHE_SIZE - offset, write_bytes);
318 struct page *page = prepared_pages[pg];
319 /*
320 * Copy data from userspace to the current page
321 *
322 * Disable pagefault to avoid recursive lock since
323 * the pages are already locked
324 */
325 pagefault_disable();
326 copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
327 pagefault_enable();
328
329 /* Flush processor's dcache for this page */
330 flush_dcache_page(page);
331
332 /*
333 * if we get a partial write, we can end up with
334 * partially up to date pages. These add
335 * a lot of complexity, so make sure they don't
336 * happen by forcing this copy to be retried.
337 *
338 * The rest of the btrfs_file_write code will fall
339 * back to page at a time copies after we return 0.
340 */
341 if (!PageUptodate(page) && copied < count)
342 copied = 0;
343
344 iov_iter_advance(i, copied);
345 write_bytes -= copied;
346 total_copied += copied;
347
348 /* Return to btrfs_file_aio_write to fault page */
349 if (unlikely(copied == 0))
350 break;
351
352 if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
353 offset += copied;
354 } else {
355 pg++;
356 offset = 0;
357 }
358 }
359 return total_copied;
360 }
361
362 /*
363 * unlocks pages after btrfs_file_write is done with them
364 */
365 void btrfs_drop_pages(struct page **pages, size_t num_pages)
366 {
367 size_t i;
368 for (i = 0; i < num_pages; i++) {
369 /* page checked is some magic around finding pages that
370 * have been modified without going through btrfs_set_page_dirty
371 * clear it here
372 */
373 ClearPageChecked(pages[i]);
374 unlock_page(pages[i]);
375 mark_page_accessed(pages[i]);
376 page_cache_release(pages[i]);
377 }
378 }
379
380 /*
381 * after copy_from_user, pages need to be dirtied and we need to make
382 * sure holes are created between the current EOF and the start of
383 * any next extents (if required).
384 *
385 * this also makes the decision about creating an inline extent vs
386 * doing real data extents, marking pages dirty and delalloc as required.
387 */
388 int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
389 struct page **pages, size_t num_pages,
390 loff_t pos, size_t write_bytes,
391 struct extent_state **cached)
392 {
393 int err = 0;
394 int i;
395 u64 num_bytes;
396 u64 start_pos;
397 u64 end_of_last_block;
398 u64 end_pos = pos + write_bytes;
399 loff_t isize = i_size_read(inode);
400
401 start_pos = pos & ~((u64)root->sectorsize - 1);
402 num_bytes = (write_bytes + pos - start_pos +
403 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
404
405 end_of_last_block = start_pos + num_bytes - 1;
406 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
407 cached);
408 if (err)
409 return err;
410
411 for (i = 0; i < num_pages; i++) {
412 struct page *p = pages[i];
413 SetPageUptodate(p);
414 ClearPageChecked(p);
415 set_page_dirty(p);
416 }
417
418 /*
419 * we've only changed i_size in ram, and we haven't updated
420 * the disk i_size. There is no need to log the inode
421 * at this time.
422 */
423 if (end_pos > isize)
424 i_size_write(inode, end_pos);
425 return 0;
426 }
427
428 /*
429 * this drops all the extents in the cache that intersect the range
430 * [start, end]. Existing extents are split as required.
431 */
432 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
433 int skip_pinned)
434 {
435 struct extent_map *em;
436 struct extent_map *split = NULL;
437 struct extent_map *split2 = NULL;
438 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
439 u64 len = end - start + 1;
440 int ret;
441 int testend = 1;
442 unsigned long flags;
443 int compressed = 0;
444
445 WARN_ON(end < start);
446 if (end == (u64)-1) {
447 len = (u64)-1;
448 testend = 0;
449 }
450 while (1) {
451 if (!split)
452 split = alloc_extent_map();
453 if (!split2)
454 split2 = alloc_extent_map();
455 BUG_ON(!split || !split2); /* -ENOMEM */
456
457 write_lock(&em_tree->lock);
458 em = lookup_extent_mapping(em_tree, start, len);
459 if (!em) {
460 write_unlock(&em_tree->lock);
461 break;
462 }
463 flags = em->flags;
464 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
465 if (testend && em->start + em->len >= start + len) {
466 free_extent_map(em);
467 write_unlock(&em_tree->lock);
468 break;
469 }
470 start = em->start + em->len;
471 if (testend)
472 len = start + len - (em->start + em->len);
473 free_extent_map(em);
474 write_unlock(&em_tree->lock);
475 continue;
476 }
477 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
478 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
479 remove_extent_mapping(em_tree, em);
480
481 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
482 em->start < start) {
483 split->start = em->start;
484 split->len = start - em->start;
485 split->orig_start = em->orig_start;
486 split->block_start = em->block_start;
487
488 if (compressed)
489 split->block_len = em->block_len;
490 else
491 split->block_len = split->len;
492
493 split->bdev = em->bdev;
494 split->flags = flags;
495 split->compress_type = em->compress_type;
496 ret = add_extent_mapping(em_tree, split);
497 BUG_ON(ret); /* Logic error */
498 free_extent_map(split);
499 split = split2;
500 split2 = NULL;
501 }
502 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
503 testend && em->start + em->len > start + len) {
504 u64 diff = start + len - em->start;
505
506 split->start = start + len;
507 split->len = em->start + em->len - (start + len);
508 split->bdev = em->bdev;
509 split->flags = flags;
510 split->compress_type = em->compress_type;
511
512 if (compressed) {
513 split->block_len = em->block_len;
514 split->block_start = em->block_start;
515 split->orig_start = em->orig_start;
516 } else {
517 split->block_len = split->len;
518 split->block_start = em->block_start + diff;
519 split->orig_start = split->start;
520 }
521
522 ret = add_extent_mapping(em_tree, split);
523 BUG_ON(ret); /* Logic error */
524 free_extent_map(split);
525 split = NULL;
526 }
527 write_unlock(&em_tree->lock);
528
529 /* once for us */
530 free_extent_map(em);
531 /* once for the tree*/
532 free_extent_map(em);
533 }
534 if (split)
535 free_extent_map(split);
536 if (split2)
537 free_extent_map(split2);
538 return 0;
539 }
540
541 /*
542 * this is very complex, but the basic idea is to drop all extents
543 * in the range start - end. hint_block is filled in with a block number
544 * that would be a good hint to the block allocator for this file.
545 *
546 * If an extent intersects the range but is not entirely inside the range
547 * it is either truncated or split. Anything entirely inside the range
548 * is deleted from the tree.
549 */
550 int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
551 u64 start, u64 end, u64 *hint_byte, int drop_cache)
552 {
553 struct btrfs_root *root = BTRFS_I(inode)->root;
554 struct extent_buffer *leaf;
555 struct btrfs_file_extent_item *fi;
556 struct btrfs_path *path;
557 struct btrfs_key key;
558 struct btrfs_key new_key;
559 u64 ino = btrfs_ino(inode);
560 u64 search_start = start;
561 u64 disk_bytenr = 0;
562 u64 num_bytes = 0;
563 u64 extent_offset = 0;
564 u64 extent_end = 0;
565 int del_nr = 0;
566 int del_slot = 0;
567 int extent_type;
568 int recow;
569 int ret;
570
571 if (drop_cache)
572 btrfs_drop_extent_cache(inode, start, end - 1, 0);
573
574 path = btrfs_alloc_path();
575 if (!path)
576 return -ENOMEM;
577
578 while (1) {
579 recow = 0;
580 ret = btrfs_lookup_file_extent(trans, root, path, ino,
581 search_start, -1);
582 if (ret < 0)
583 break;
584 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
585 leaf = path->nodes[0];
586 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
587 if (key.objectid == ino &&
588 key.type == BTRFS_EXTENT_DATA_KEY)
589 path->slots[0]--;
590 }
591 ret = 0;
592 next_slot:
593 leaf = path->nodes[0];
594 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
595 BUG_ON(del_nr > 0);
596 ret = btrfs_next_leaf(root, path);
597 if (ret < 0)
598 break;
599 if (ret > 0) {
600 ret = 0;
601 break;
602 }
603 leaf = path->nodes[0];
604 recow = 1;
605 }
606
607 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
608 if (key.objectid > ino ||
609 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
610 break;
611
612 fi = btrfs_item_ptr(leaf, path->slots[0],
613 struct btrfs_file_extent_item);
614 extent_type = btrfs_file_extent_type(leaf, fi);
615
616 if (extent_type == BTRFS_FILE_EXTENT_REG ||
617 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
618 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
619 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
620 extent_offset = btrfs_file_extent_offset(leaf, fi);
621 extent_end = key.offset +
622 btrfs_file_extent_num_bytes(leaf, fi);
623 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
624 extent_end = key.offset +
625 btrfs_file_extent_inline_len(leaf, fi);
626 } else {
627 WARN_ON(1);
628 extent_end = search_start;
629 }
630
631 if (extent_end <= search_start) {
632 path->slots[0]++;
633 goto next_slot;
634 }
635
636 search_start = max(key.offset, start);
637 if (recow) {
638 btrfs_release_path(path);
639 continue;
640 }
641
642 /*
643 * | - range to drop - |
644 * | -------- extent -------- |
645 */
646 if (start > key.offset && end < extent_end) {
647 BUG_ON(del_nr > 0);
648 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
649
650 memcpy(&new_key, &key, sizeof(new_key));
651 new_key.offset = start;
652 ret = btrfs_duplicate_item(trans, root, path,
653 &new_key);
654 if (ret == -EAGAIN) {
655 btrfs_release_path(path);
656 continue;
657 }
658 if (ret < 0)
659 break;
660
661 leaf = path->nodes[0];
662 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
663 struct btrfs_file_extent_item);
664 btrfs_set_file_extent_num_bytes(leaf, fi,
665 start - key.offset);
666
667 fi = btrfs_item_ptr(leaf, path->slots[0],
668 struct btrfs_file_extent_item);
669
670 extent_offset += start - key.offset;
671 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
672 btrfs_set_file_extent_num_bytes(leaf, fi,
673 extent_end - start);
674 btrfs_mark_buffer_dirty(leaf);
675
676 if (disk_bytenr > 0) {
677 ret = btrfs_inc_extent_ref(trans, root,
678 disk_bytenr, num_bytes, 0,
679 root->root_key.objectid,
680 new_key.objectid,
681 start - extent_offset, 0);
682 BUG_ON(ret); /* -ENOMEM */
683 *hint_byte = disk_bytenr;
684 }
685 key.offset = start;
686 }
687 /*
688 * | ---- range to drop ----- |
689 * | -------- extent -------- |
690 */
691 if (start <= key.offset && end < extent_end) {
692 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
693
694 memcpy(&new_key, &key, sizeof(new_key));
695 new_key.offset = end;
696 btrfs_set_item_key_safe(trans, root, path, &new_key);
697
698 extent_offset += end - key.offset;
699 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
700 btrfs_set_file_extent_num_bytes(leaf, fi,
701 extent_end - end);
702 btrfs_mark_buffer_dirty(leaf);
703 if (disk_bytenr > 0) {
704 inode_sub_bytes(inode, end - key.offset);
705 *hint_byte = disk_bytenr;
706 }
707 break;
708 }
709
710 search_start = extent_end;
711 /*
712 * | ---- range to drop ----- |
713 * | -------- extent -------- |
714 */
715 if (start > key.offset && end >= extent_end) {
716 BUG_ON(del_nr > 0);
717 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
718
719 btrfs_set_file_extent_num_bytes(leaf, fi,
720 start - key.offset);
721 btrfs_mark_buffer_dirty(leaf);
722 if (disk_bytenr > 0) {
723 inode_sub_bytes(inode, extent_end - start);
724 *hint_byte = disk_bytenr;
725 }
726 if (end == extent_end)
727 break;
728
729 path->slots[0]++;
730 goto next_slot;
731 }
732
733 /*
734 * | ---- range to drop ----- |
735 * | ------ extent ------ |
736 */
737 if (start <= key.offset && end >= extent_end) {
738 if (del_nr == 0) {
739 del_slot = path->slots[0];
740 del_nr = 1;
741 } else {
742 BUG_ON(del_slot + del_nr != path->slots[0]);
743 del_nr++;
744 }
745
746 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
747 inode_sub_bytes(inode,
748 extent_end - key.offset);
749 extent_end = ALIGN(extent_end,
750 root->sectorsize);
751 } else if (disk_bytenr > 0) {
752 ret = btrfs_free_extent(trans, root,
753 disk_bytenr, num_bytes, 0,
754 root->root_key.objectid,
755 key.objectid, key.offset -
756 extent_offset, 0);
757 BUG_ON(ret); /* -ENOMEM */
758 inode_sub_bytes(inode,
759 extent_end - key.offset);
760 *hint_byte = disk_bytenr;
761 }
762
763 if (end == extent_end)
764 break;
765
766 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
767 path->slots[0]++;
768 goto next_slot;
769 }
770
771 ret = btrfs_del_items(trans, root, path, del_slot,
772 del_nr);
773 if (ret) {
774 btrfs_abort_transaction(trans, root, ret);
775 goto out;
776 }
777
778 del_nr = 0;
779 del_slot = 0;
780
781 btrfs_release_path(path);
782 continue;
783 }
784
785 BUG_ON(1);
786 }
787
788 if (!ret && del_nr > 0) {
789 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
790 if (ret)
791 btrfs_abort_transaction(trans, root, ret);
792 }
793
794 out:
795 btrfs_free_path(path);
796 return ret;
797 }
798
799 static int extent_mergeable(struct extent_buffer *leaf, int slot,
800 u64 objectid, u64 bytenr, u64 orig_offset,
801 u64 *start, u64 *end)
802 {
803 struct btrfs_file_extent_item *fi;
804 struct btrfs_key key;
805 u64 extent_end;
806
807 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
808 return 0;
809
810 btrfs_item_key_to_cpu(leaf, &key, slot);
811 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
812 return 0;
813
814 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
815 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
816 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
817 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
818 btrfs_file_extent_compression(leaf, fi) ||
819 btrfs_file_extent_encryption(leaf, fi) ||
820 btrfs_file_extent_other_encoding(leaf, fi))
821 return 0;
822
823 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
824 if ((*start && *start != key.offset) || (*end && *end != extent_end))
825 return 0;
826
827 *start = key.offset;
828 *end = extent_end;
829 return 1;
830 }
831
832 /*
833 * Mark extent in the range start - end as written.
834 *
835 * This changes extent type from 'pre-allocated' to 'regular'. If only
836 * part of extent is marked as written, the extent will be split into
837 * two or three.
838 */
839 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
840 struct inode *inode, u64 start, u64 end)
841 {
842 struct btrfs_root *root = BTRFS_I(inode)->root;
843 struct extent_buffer *leaf;
844 struct btrfs_path *path;
845 struct btrfs_file_extent_item *fi;
846 struct btrfs_key key;
847 struct btrfs_key new_key;
848 u64 bytenr;
849 u64 num_bytes;
850 u64 extent_end;
851 u64 orig_offset;
852 u64 other_start;
853 u64 other_end;
854 u64 split;
855 int del_nr = 0;
856 int del_slot = 0;
857 int recow;
858 int ret;
859 u64 ino = btrfs_ino(inode);
860
861 btrfs_drop_extent_cache(inode, start, end - 1, 0);
862
863 path = btrfs_alloc_path();
864 if (!path)
865 return -ENOMEM;
866 again:
867 recow = 0;
868 split = start;
869 key.objectid = ino;
870 key.type = BTRFS_EXTENT_DATA_KEY;
871 key.offset = split;
872
873 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
874 if (ret < 0)
875 goto out;
876 if (ret > 0 && path->slots[0] > 0)
877 path->slots[0]--;
878
879 leaf = path->nodes[0];
880 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
881 BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
882 fi = btrfs_item_ptr(leaf, path->slots[0],
883 struct btrfs_file_extent_item);
884 BUG_ON(btrfs_file_extent_type(leaf, fi) !=
885 BTRFS_FILE_EXTENT_PREALLOC);
886 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
887 BUG_ON(key.offset > start || extent_end < end);
888
889 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
890 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
891 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
892 memcpy(&new_key, &key, sizeof(new_key));
893
894 if (start == key.offset && end < extent_end) {
895 other_start = 0;
896 other_end = start;
897 if (extent_mergeable(leaf, path->slots[0] - 1,
898 ino, bytenr, orig_offset,
899 &other_start, &other_end)) {
900 new_key.offset = end;
901 btrfs_set_item_key_safe(trans, root, path, &new_key);
902 fi = btrfs_item_ptr(leaf, path->slots[0],
903 struct btrfs_file_extent_item);
904 btrfs_set_file_extent_num_bytes(leaf, fi,
905 extent_end - end);
906 btrfs_set_file_extent_offset(leaf, fi,
907 end - orig_offset);
908 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
909 struct btrfs_file_extent_item);
910 btrfs_set_file_extent_num_bytes(leaf, fi,
911 end - other_start);
912 btrfs_mark_buffer_dirty(leaf);
913 goto out;
914 }
915 }
916
917 if (start > key.offset && end == extent_end) {
918 other_start = end;
919 other_end = 0;
920 if (extent_mergeable(leaf, path->slots[0] + 1,
921 ino, bytenr, orig_offset,
922 &other_start, &other_end)) {
923 fi = btrfs_item_ptr(leaf, path->slots[0],
924 struct btrfs_file_extent_item);
925 btrfs_set_file_extent_num_bytes(leaf, fi,
926 start - key.offset);
927 path->slots[0]++;
928 new_key.offset = start;
929 btrfs_set_item_key_safe(trans, root, path, &new_key);
930
931 fi = btrfs_item_ptr(leaf, path->slots[0],
932 struct btrfs_file_extent_item);
933 btrfs_set_file_extent_num_bytes(leaf, fi,
934 other_end - start);
935 btrfs_set_file_extent_offset(leaf, fi,
936 start - orig_offset);
937 btrfs_mark_buffer_dirty(leaf);
938 goto out;
939 }
940 }
941
942 while (start > key.offset || end < extent_end) {
943 if (key.offset == start)
944 split = end;
945
946 new_key.offset = split;
947 ret = btrfs_duplicate_item(trans, root, path, &new_key);
948 if (ret == -EAGAIN) {
949 btrfs_release_path(path);
950 goto again;
951 }
952 if (ret < 0) {
953 btrfs_abort_transaction(trans, root, ret);
954 goto out;
955 }
956
957 leaf = path->nodes[0];
958 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
959 struct btrfs_file_extent_item);
960 btrfs_set_file_extent_num_bytes(leaf, fi,
961 split - key.offset);
962
963 fi = btrfs_item_ptr(leaf, path->slots[0],
964 struct btrfs_file_extent_item);
965
966 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
967 btrfs_set_file_extent_num_bytes(leaf, fi,
968 extent_end - split);
969 btrfs_mark_buffer_dirty(leaf);
970
971 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
972 root->root_key.objectid,
973 ino, orig_offset, 0);
974 BUG_ON(ret); /* -ENOMEM */
975
976 if (split == start) {
977 key.offset = start;
978 } else {
979 BUG_ON(start != key.offset);
980 path->slots[0]--;
981 extent_end = end;
982 }
983 recow = 1;
984 }
985
986 other_start = end;
987 other_end = 0;
988 if (extent_mergeable(leaf, path->slots[0] + 1,
989 ino, bytenr, orig_offset,
990 &other_start, &other_end)) {
991 if (recow) {
992 btrfs_release_path(path);
993 goto again;
994 }
995 extent_end = other_end;
996 del_slot = path->slots[0] + 1;
997 del_nr++;
998 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
999 0, root->root_key.objectid,
1000 ino, orig_offset, 0);
1001 BUG_ON(ret); /* -ENOMEM */
1002 }
1003 other_start = 0;
1004 other_end = start;
1005 if (extent_mergeable(leaf, path->slots[0] - 1,
1006 ino, bytenr, orig_offset,
1007 &other_start, &other_end)) {
1008 if (recow) {
1009 btrfs_release_path(path);
1010 goto again;
1011 }
1012 key.offset = other_start;
1013 del_slot = path->slots[0];
1014 del_nr++;
1015 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1016 0, root->root_key.objectid,
1017 ino, orig_offset, 0);
1018 BUG_ON(ret); /* -ENOMEM */
1019 }
1020 if (del_nr == 0) {
1021 fi = btrfs_item_ptr(leaf, path->slots[0],
1022 struct btrfs_file_extent_item);
1023 btrfs_set_file_extent_type(leaf, fi,
1024 BTRFS_FILE_EXTENT_REG);
1025 btrfs_mark_buffer_dirty(leaf);
1026 } else {
1027 fi = btrfs_item_ptr(leaf, del_slot - 1,
1028 struct btrfs_file_extent_item);
1029 btrfs_set_file_extent_type(leaf, fi,
1030 BTRFS_FILE_EXTENT_REG);
1031 btrfs_set_file_extent_num_bytes(leaf, fi,
1032 extent_end - key.offset);
1033 btrfs_mark_buffer_dirty(leaf);
1034
1035 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1036 if (ret < 0) {
1037 btrfs_abort_transaction(trans, root, ret);
1038 goto out;
1039 }
1040 }
1041 out:
1042 btrfs_free_path(path);
1043 return 0;
1044 }
1045
1046 /*
1047 * on error we return an unlocked page and the error value
1048 * on success we return a locked page and 0
1049 */
1050 static int prepare_uptodate_page(struct page *page, u64 pos,
1051 bool force_uptodate)
1052 {
1053 int ret = 0;
1054
1055 if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) &&
1056 !PageUptodate(page)) {
1057 ret = btrfs_readpage(NULL, page);
1058 if (ret)
1059 return ret;
1060 lock_page(page);
1061 if (!PageUptodate(page)) {
1062 unlock_page(page);
1063 return -EIO;
1064 }
1065 }
1066 return 0;
1067 }
1068
1069 /*
1070 * this gets pages into the page cache and locks them down, it also properly
1071 * waits for data=ordered extents to finish before allowing the pages to be
1072 * modified.
1073 */
1074 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
1075 struct page **pages, size_t num_pages,
1076 loff_t pos, unsigned long first_index,
1077 size_t write_bytes, bool force_uptodate)
1078 {
1079 struct extent_state *cached_state = NULL;
1080 int i;
1081 unsigned long index = pos >> PAGE_CACHE_SHIFT;
1082 struct inode *inode = fdentry(file)->d_inode;
1083 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1084 int err = 0;
1085 int faili = 0;
1086 u64 start_pos;
1087 u64 last_pos;
1088
1089 start_pos = pos & ~((u64)root->sectorsize - 1);
1090 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
1091
1092 again:
1093 for (i = 0; i < num_pages; i++) {
1094 pages[i] = find_or_create_page(inode->i_mapping, index + i,
1095 mask | __GFP_WRITE);
1096 if (!pages[i]) {
1097 faili = i - 1;
1098 err = -ENOMEM;
1099 goto fail;
1100 }
1101
1102 if (i == 0)
1103 err = prepare_uptodate_page(pages[i], pos,
1104 force_uptodate);
1105 if (i == num_pages - 1)
1106 err = prepare_uptodate_page(pages[i],
1107 pos + write_bytes, false);
1108 if (err) {
1109 page_cache_release(pages[i]);
1110 faili = i - 1;
1111 goto fail;
1112 }
1113 wait_on_page_writeback(pages[i]);
1114 }
1115 err = 0;
1116 if (start_pos < inode->i_size) {
1117 struct btrfs_ordered_extent *ordered;
1118 lock_extent_bits(&BTRFS_I(inode)->io_tree,
1119 start_pos, last_pos - 1, 0, &cached_state);
1120 ordered = btrfs_lookup_first_ordered_extent(inode,
1121 last_pos - 1);
1122 if (ordered &&
1123 ordered->file_offset + ordered->len > start_pos &&
1124 ordered->file_offset < last_pos) {
1125 btrfs_put_ordered_extent(ordered);
1126 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1127 start_pos, last_pos - 1,
1128 &cached_state, GFP_NOFS);
1129 for (i = 0; i < num_pages; i++) {
1130 unlock_page(pages[i]);
1131 page_cache_release(pages[i]);
1132 }
1133 btrfs_wait_ordered_range(inode, start_pos,
1134 last_pos - start_pos);
1135 goto again;
1136 }
1137 if (ordered)
1138 btrfs_put_ordered_extent(ordered);
1139
1140 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
1141 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1142 EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
1143 GFP_NOFS);
1144 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1145 start_pos, last_pos - 1, &cached_state,
1146 GFP_NOFS);
1147 }
1148 for (i = 0; i < num_pages; i++) {
1149 if (clear_page_dirty_for_io(pages[i]))
1150 account_page_redirty(pages[i]);
1151 set_page_extent_mapped(pages[i]);
1152 WARN_ON(!PageLocked(pages[i]));
1153 }
1154 return 0;
1155 fail:
1156 while (faili >= 0) {
1157 unlock_page(pages[faili]);
1158 page_cache_release(pages[faili]);
1159 faili--;
1160 }
1161 return err;
1162
1163 }
1164
1165 static noinline ssize_t __btrfs_buffered_write(struct file *file,
1166 struct iov_iter *i,
1167 loff_t pos)
1168 {
1169 struct inode *inode = fdentry(file)->d_inode;
1170 struct btrfs_root *root = BTRFS_I(inode)->root;
1171 struct page **pages = NULL;
1172 unsigned long first_index;
1173 size_t num_written = 0;
1174 int nrptrs;
1175 int ret = 0;
1176 bool force_page_uptodate = false;
1177
1178 nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
1179 PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
1180 (sizeof(struct page *)));
1181 nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
1182 nrptrs = max(nrptrs, 8);
1183 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1184 if (!pages)
1185 return -ENOMEM;
1186
1187 first_index = pos >> PAGE_CACHE_SHIFT;
1188
1189 while (iov_iter_count(i) > 0) {
1190 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1191 size_t write_bytes = min(iov_iter_count(i),
1192 nrptrs * (size_t)PAGE_CACHE_SIZE -
1193 offset);
1194 size_t num_pages = (write_bytes + offset +
1195 PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1196 size_t dirty_pages;
1197 size_t copied;
1198
1199 WARN_ON(num_pages > nrptrs);
1200
1201 /*
1202 * Fault pages before locking them in prepare_pages
1203 * to avoid recursive lock
1204 */
1205 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1206 ret = -EFAULT;
1207 break;
1208 }
1209
1210 ret = btrfs_delalloc_reserve_space(inode,
1211 num_pages << PAGE_CACHE_SHIFT);
1212 if (ret)
1213 break;
1214
1215 /*
1216 * This is going to setup the pages array with the number of
1217 * pages we want, so we don't really need to worry about the
1218 * contents of pages from loop to loop
1219 */
1220 ret = prepare_pages(root, file, pages, num_pages,
1221 pos, first_index, write_bytes,
1222 force_page_uptodate);
1223 if (ret) {
1224 btrfs_delalloc_release_space(inode,
1225 num_pages << PAGE_CACHE_SHIFT);
1226 break;
1227 }
1228
1229 copied = btrfs_copy_from_user(pos, num_pages,
1230 write_bytes, pages, i);
1231
1232 /*
1233 * if we have trouble faulting in the pages, fall
1234 * back to one page at a time
1235 */
1236 if (copied < write_bytes)
1237 nrptrs = 1;
1238
1239 if (copied == 0) {
1240 force_page_uptodate = true;
1241 dirty_pages = 0;
1242 } else {
1243 force_page_uptodate = false;
1244 dirty_pages = (copied + offset +
1245 PAGE_CACHE_SIZE - 1) >>
1246 PAGE_CACHE_SHIFT;
1247 }
1248
1249 /*
1250 * If we had a short copy we need to release the excess delaloc
1251 * bytes we reserved. We need to increment outstanding_extents
1252 * because btrfs_delalloc_release_space will decrement it, but
1253 * we still have an outstanding extent for the chunk we actually
1254 * managed to copy.
1255 */
1256 if (num_pages > dirty_pages) {
1257 if (copied > 0) {
1258 spin_lock(&BTRFS_I(inode)->lock);
1259 BTRFS_I(inode)->outstanding_extents++;
1260 spin_unlock(&BTRFS_I(inode)->lock);
1261 }
1262 btrfs_delalloc_release_space(inode,
1263 (num_pages - dirty_pages) <<
1264 PAGE_CACHE_SHIFT);
1265 }
1266
1267 if (copied > 0) {
1268 ret = btrfs_dirty_pages(root, inode, pages,
1269 dirty_pages, pos, copied,
1270 NULL);
1271 if (ret) {
1272 btrfs_delalloc_release_space(inode,
1273 dirty_pages << PAGE_CACHE_SHIFT);
1274 btrfs_drop_pages(pages, num_pages);
1275 break;
1276 }
1277 }
1278
1279 btrfs_drop_pages(pages, num_pages);
1280
1281 cond_resched();
1282
1283 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1284 dirty_pages);
1285 if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1286 btrfs_btree_balance_dirty(root, 1);
1287
1288 pos += copied;
1289 num_written += copied;
1290 }
1291
1292 kfree(pages);
1293
1294 return num_written ? num_written : ret;
1295 }
1296
1297 static ssize_t __btrfs_direct_write(struct kiocb *iocb,
1298 const struct iovec *iov,
1299 unsigned long nr_segs, loff_t pos,
1300 loff_t *ppos, size_t count, size_t ocount)
1301 {
1302 struct file *file = iocb->ki_filp;
1303 struct inode *inode = fdentry(file)->d_inode;
1304 struct iov_iter i;
1305 ssize_t written;
1306 ssize_t written_buffered;
1307 loff_t endbyte;
1308 int err;
1309
1310 written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
1311 count, ocount);
1312
1313 /*
1314 * the generic O_DIRECT will update in-memory i_size after the
1315 * DIOs are done. But our endio handlers that update the on
1316 * disk i_size never update past the in memory i_size. So we
1317 * need one more update here to catch any additions to the
1318 * file
1319 */
1320 if (inode->i_size != BTRFS_I(inode)->disk_i_size) {
1321 btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
1322 mark_inode_dirty(inode);
1323 }
1324
1325 if (written < 0 || written == count)
1326 return written;
1327
1328 pos += written;
1329 count -= written;
1330 iov_iter_init(&i, iov, nr_segs, count, written);
1331 written_buffered = __btrfs_buffered_write(file, &i, pos);
1332 if (written_buffered < 0) {
1333 err = written_buffered;
1334 goto out;
1335 }
1336 endbyte = pos + written_buffered - 1;
1337 err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
1338 if (err)
1339 goto out;
1340 written += written_buffered;
1341 *ppos = pos + written_buffered;
1342 invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
1343 endbyte >> PAGE_CACHE_SHIFT);
1344 out:
1345 return written ? written : err;
1346 }
1347
1348 static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
1349 const struct iovec *iov,
1350 unsigned long nr_segs, loff_t pos)
1351 {
1352 struct file *file = iocb->ki_filp;
1353 struct inode *inode = fdentry(file)->d_inode;
1354 struct btrfs_root *root = BTRFS_I(inode)->root;
1355 loff_t *ppos = &iocb->ki_pos;
1356 u64 start_pos;
1357 ssize_t num_written = 0;
1358 ssize_t err = 0;
1359 size_t count, ocount;
1360
1361 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
1362
1363 mutex_lock(&inode->i_mutex);
1364
1365 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1366 if (err) {
1367 mutex_unlock(&inode->i_mutex);
1368 goto out;
1369 }
1370 count = ocount;
1371
1372 current->backing_dev_info = inode->i_mapping->backing_dev_info;
1373 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1374 if (err) {
1375 mutex_unlock(&inode->i_mutex);
1376 goto out;
1377 }
1378
1379 if (count == 0) {
1380 mutex_unlock(&inode->i_mutex);
1381 goto out;
1382 }
1383
1384 err = file_remove_suid(file);
1385 if (err) {
1386 mutex_unlock(&inode->i_mutex);
1387 goto out;
1388 }
1389
1390 /*
1391 * If BTRFS flips readonly due to some impossible error
1392 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1393 * although we have opened a file as writable, we have
1394 * to stop this write operation to ensure FS consistency.
1395 */
1396 if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
1397 mutex_unlock(&inode->i_mutex);
1398 err = -EROFS;
1399 goto out;
1400 }
1401
1402 err = btrfs_update_time(file);
1403 if (err) {
1404 mutex_unlock(&inode->i_mutex);
1405 goto out;
1406 }
1407 BTRFS_I(inode)->sequence++;
1408
1409 start_pos = round_down(pos, root->sectorsize);
1410 if (start_pos > i_size_read(inode)) {
1411 err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
1412 if (err) {
1413 mutex_unlock(&inode->i_mutex);
1414 goto out;
1415 }
1416 }
1417
1418 if (unlikely(file->f_flags & O_DIRECT)) {
1419 num_written = __btrfs_direct_write(iocb, iov, nr_segs,
1420 pos, ppos, count, ocount);
1421 } else {
1422 struct iov_iter i;
1423
1424 iov_iter_init(&i, iov, nr_segs, count, num_written);
1425
1426 num_written = __btrfs_buffered_write(file, &i, pos);
1427 if (num_written > 0)
1428 *ppos = pos + num_written;
1429 }
1430
1431 mutex_unlock(&inode->i_mutex);
1432
1433 /*
1434 * we want to make sure fsync finds this change
1435 * but we haven't joined a transaction running right now.
1436 *
1437 * Later on, someone is sure to update the inode and get the
1438 * real transid recorded.
1439 *
1440 * We set last_trans now to the fs_info generation + 1,
1441 * this will either be one more than the running transaction
1442 * or the generation used for the next transaction if there isn't
1443 * one running right now.
1444 */
1445 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1446 if (num_written > 0 || num_written == -EIOCBQUEUED) {
1447 err = generic_write_sync(file, pos, num_written);
1448 if (err < 0 && num_written > 0)
1449 num_written = err;
1450 }
1451 out:
1452 current->backing_dev_info = NULL;
1453 return num_written ? num_written : err;
1454 }
1455
1456 int btrfs_release_file(struct inode *inode, struct file *filp)
1457 {
1458 /*
1459 * ordered_data_close is set by settattr when we are about to truncate
1460 * a file from a non-zero size to a zero size. This tries to
1461 * flush down new bytes that may have been written if the
1462 * application were using truncate to replace a file in place.
1463 */
1464 if (BTRFS_I(inode)->ordered_data_close) {
1465 BTRFS_I(inode)->ordered_data_close = 0;
1466 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1467 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1468 filemap_flush(inode->i_mapping);
1469 }
1470 if (filp->private_data)
1471 btrfs_ioctl_trans_end(filp);
1472 return 0;
1473 }
1474
1475 /*
1476 * fsync call for both files and directories. This logs the inode into
1477 * the tree log instead of forcing full commits whenever possible.
1478 *
1479 * It needs to call filemap_fdatawait so that all ordered extent updates are
1480 * in the metadata btree are up to date for copying to the log.
1481 *
1482 * It drops the inode mutex before doing the tree log commit. This is an
1483 * important optimization for directories because holding the mutex prevents
1484 * new operations on the dir while we write to disk.
1485 */
1486 int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
1487 {
1488 struct dentry *dentry = file->f_path.dentry;
1489 struct inode *inode = dentry->d_inode;
1490 struct btrfs_root *root = BTRFS_I(inode)->root;
1491 int ret = 0;
1492 struct btrfs_trans_handle *trans;
1493
1494 trace_btrfs_sync_file(file, datasync);
1495
1496 ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
1497 if (ret)
1498 return ret;
1499 mutex_lock(&inode->i_mutex);
1500
1501 /* we wait first, since the writeback may change the inode */
1502 root->log_batch++;
1503 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1504 root->log_batch++;
1505
1506 /*
1507 * check the transaction that last modified this inode
1508 * and see if its already been committed
1509 */
1510 if (!BTRFS_I(inode)->last_trans) {
1511 mutex_unlock(&inode->i_mutex);
1512 goto out;
1513 }
1514
1515 /*
1516 * if the last transaction that changed this file was before
1517 * the current transaction, we can bail out now without any
1518 * syncing
1519 */
1520 smp_mb();
1521 if (BTRFS_I(inode)->last_trans <=
1522 root->fs_info->last_trans_committed) {
1523 BTRFS_I(inode)->last_trans = 0;
1524 mutex_unlock(&inode->i_mutex);
1525 goto out;
1526 }
1527
1528 /*
1529 * ok we haven't committed the transaction yet, lets do a commit
1530 */
1531 if (file->private_data)
1532 btrfs_ioctl_trans_end(file);
1533
1534 trans = btrfs_start_transaction(root, 0);
1535 if (IS_ERR(trans)) {
1536 ret = PTR_ERR(trans);
1537 mutex_unlock(&inode->i_mutex);
1538 goto out;
1539 }
1540
1541 ret = btrfs_log_dentry_safe(trans, root, dentry);
1542 if (ret < 0) {
1543 mutex_unlock(&inode->i_mutex);
1544 goto out;
1545 }
1546
1547 /* we've logged all the items and now have a consistent
1548 * version of the file in the log. It is possible that
1549 * someone will come in and modify the file, but that's
1550 * fine because the log is consistent on disk, and we
1551 * have references to all of the file's extents
1552 *
1553 * It is possible that someone will come in and log the
1554 * file again, but that will end up using the synchronization
1555 * inside btrfs_sync_log to keep things safe.
1556 */
1557 mutex_unlock(&inode->i_mutex);
1558
1559 if (ret != BTRFS_NO_LOG_SYNC) {
1560 if (ret > 0) {
1561 ret = btrfs_commit_transaction(trans, root);
1562 } else {
1563 ret = btrfs_sync_log(trans, root);
1564 if (ret == 0)
1565 ret = btrfs_end_transaction(trans, root);
1566 else
1567 ret = btrfs_commit_transaction(trans, root);
1568 }
1569 } else {
1570 ret = btrfs_end_transaction(trans, root);
1571 }
1572 out:
1573 return ret > 0 ? -EIO : ret;
1574 }
1575
1576 static const struct vm_operations_struct btrfs_file_vm_ops = {
1577 .fault = filemap_fault,
1578 .page_mkwrite = btrfs_page_mkwrite,
1579 };
1580
1581 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1582 {
1583 struct address_space *mapping = filp->f_mapping;
1584
1585 if (!mapping->a_ops->readpage)
1586 return -ENOEXEC;
1587
1588 file_accessed(filp);
1589 vma->vm_ops = &btrfs_file_vm_ops;
1590 vma->vm_flags |= VM_CAN_NONLINEAR;
1591
1592 return 0;
1593 }
1594
1595 static long btrfs_fallocate(struct file *file, int mode,
1596 loff_t offset, loff_t len)
1597 {
1598 struct inode *inode = file->f_path.dentry->d_inode;
1599 struct extent_state *cached_state = NULL;
1600 u64 cur_offset;
1601 u64 last_byte;
1602 u64 alloc_start;
1603 u64 alloc_end;
1604 u64 alloc_hint = 0;
1605 u64 locked_end;
1606 u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
1607 struct extent_map *em;
1608 int ret;
1609
1610 alloc_start = offset & ~mask;
1611 alloc_end = (offset + len + mask) & ~mask;
1612
1613 /* We only support the FALLOC_FL_KEEP_SIZE mode */
1614 if (mode & ~FALLOC_FL_KEEP_SIZE)
1615 return -EOPNOTSUPP;
1616
1617 /*
1618 * Make sure we have enough space before we do the
1619 * allocation.
1620 */
1621 ret = btrfs_check_data_free_space(inode, len);
1622 if (ret)
1623 return ret;
1624
1625 /*
1626 * wait for ordered IO before we have any locks. We'll loop again
1627 * below with the locks held.
1628 */
1629 btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
1630
1631 mutex_lock(&inode->i_mutex);
1632 ret = inode_newsize_ok(inode, alloc_end);
1633 if (ret)
1634 goto out;
1635
1636 if (alloc_start > inode->i_size) {
1637 ret = btrfs_cont_expand(inode, i_size_read(inode),
1638 alloc_start);
1639 if (ret)
1640 goto out;
1641 }
1642
1643 locked_end = alloc_end - 1;
1644 while (1) {
1645 struct btrfs_ordered_extent *ordered;
1646
1647 /* the extent lock is ordered inside the running
1648 * transaction
1649 */
1650 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
1651 locked_end, 0, &cached_state);
1652 ordered = btrfs_lookup_first_ordered_extent(inode,
1653 alloc_end - 1);
1654 if (ordered &&
1655 ordered->file_offset + ordered->len > alloc_start &&
1656 ordered->file_offset < alloc_end) {
1657 btrfs_put_ordered_extent(ordered);
1658 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1659 alloc_start, locked_end,
1660 &cached_state, GFP_NOFS);
1661 /*
1662 * we can't wait on the range with the transaction
1663 * running or with the extent lock held
1664 */
1665 btrfs_wait_ordered_range(inode, alloc_start,
1666 alloc_end - alloc_start);
1667 } else {
1668 if (ordered)
1669 btrfs_put_ordered_extent(ordered);
1670 break;
1671 }
1672 }
1673
1674 cur_offset = alloc_start;
1675 while (1) {
1676 u64 actual_end;
1677
1678 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
1679 alloc_end - cur_offset, 0);
1680 if (IS_ERR_OR_NULL(em)) {
1681 if (!em)
1682 ret = -ENOMEM;
1683 else
1684 ret = PTR_ERR(em);
1685 break;
1686 }
1687 last_byte = min(extent_map_end(em), alloc_end);
1688 actual_end = min_t(u64, extent_map_end(em), offset + len);
1689 last_byte = (last_byte + mask) & ~mask;
1690
1691 if (em->block_start == EXTENT_MAP_HOLE ||
1692 (cur_offset >= inode->i_size &&
1693 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
1694 ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
1695 last_byte - cur_offset,
1696 1 << inode->i_blkbits,
1697 offset + len,
1698 &alloc_hint);
1699
1700 if (ret < 0) {
1701 free_extent_map(em);
1702 break;
1703 }
1704 } else if (actual_end > inode->i_size &&
1705 !(mode & FALLOC_FL_KEEP_SIZE)) {
1706 /*
1707 * We didn't need to allocate any more space, but we
1708 * still extended the size of the file so we need to
1709 * update i_size.
1710 */
1711 inode->i_ctime = CURRENT_TIME;
1712 i_size_write(inode, actual_end);
1713 btrfs_ordered_update_i_size(inode, actual_end, NULL);
1714 }
1715 free_extent_map(em);
1716
1717 cur_offset = last_byte;
1718 if (cur_offset >= alloc_end) {
1719 ret = 0;
1720 break;
1721 }
1722 }
1723 unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
1724 &cached_state, GFP_NOFS);
1725 out:
1726 mutex_unlock(&inode->i_mutex);
1727 /* Let go of our reservation. */
1728 btrfs_free_reserved_data_space(inode, len);
1729 return ret;
1730 }
1731
1732 static int find_desired_extent(struct inode *inode, loff_t *offset, int origin)
1733 {
1734 struct btrfs_root *root = BTRFS_I(inode)->root;
1735 struct extent_map *em;
1736 struct extent_state *cached_state = NULL;
1737 u64 lockstart = *offset;
1738 u64 lockend = i_size_read(inode);
1739 u64 start = *offset;
1740 u64 orig_start = *offset;
1741 u64 len = i_size_read(inode);
1742 u64 last_end = 0;
1743 int ret = 0;
1744
1745 lockend = max_t(u64, root->sectorsize, lockend);
1746 if (lockend <= lockstart)
1747 lockend = lockstart + root->sectorsize;
1748
1749 len = lockend - lockstart + 1;
1750
1751 len = max_t(u64, len, root->sectorsize);
1752 if (inode->i_size == 0)
1753 return -ENXIO;
1754
1755 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0,
1756 &cached_state);
1757
1758 /*
1759 * Delalloc is such a pain. If we have a hole and we have pending
1760 * delalloc for a portion of the hole we will get back a hole that
1761 * exists for the entire range since it hasn't been actually written
1762 * yet. So to take care of this case we need to look for an extent just
1763 * before the position we want in case there is outstanding delalloc
1764 * going on here.
1765 */
1766 if (origin == SEEK_HOLE && start != 0) {
1767 if (start <= root->sectorsize)
1768 em = btrfs_get_extent_fiemap(inode, NULL, 0, 0,
1769 root->sectorsize, 0);
1770 else
1771 em = btrfs_get_extent_fiemap(inode, NULL, 0,
1772 start - root->sectorsize,
1773 root->sectorsize, 0);
1774 if (IS_ERR(em)) {
1775 ret = PTR_ERR(em);
1776 goto out;
1777 }
1778 last_end = em->start + em->len;
1779 if (em->block_start == EXTENT_MAP_DELALLOC)
1780 last_end = min_t(u64, last_end, inode->i_size);
1781 free_extent_map(em);
1782 }
1783
1784 while (1) {
1785 em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
1786 if (IS_ERR(em)) {
1787 ret = PTR_ERR(em);
1788 break;
1789 }
1790
1791 if (em->block_start == EXTENT_MAP_HOLE) {
1792 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
1793 if (last_end <= orig_start) {
1794 free_extent_map(em);
1795 ret = -ENXIO;
1796 break;
1797 }
1798 }
1799
1800 if (origin == SEEK_HOLE) {
1801 *offset = start;
1802 free_extent_map(em);
1803 break;
1804 }
1805 } else {
1806 if (origin == SEEK_DATA) {
1807 if (em->block_start == EXTENT_MAP_DELALLOC) {
1808 if (start >= inode->i_size) {
1809 free_extent_map(em);
1810 ret = -ENXIO;
1811 break;
1812 }
1813 }
1814
1815 *offset = start;
1816 free_extent_map(em);
1817 break;
1818 }
1819 }
1820
1821 start = em->start + em->len;
1822 last_end = em->start + em->len;
1823
1824 if (em->block_start == EXTENT_MAP_DELALLOC)
1825 last_end = min_t(u64, last_end, inode->i_size);
1826
1827 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
1828 free_extent_map(em);
1829 ret = -ENXIO;
1830 break;
1831 }
1832 free_extent_map(em);
1833 cond_resched();
1834 }
1835 if (!ret)
1836 *offset = min(*offset, inode->i_size);
1837 out:
1838 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
1839 &cached_state, GFP_NOFS);
1840 return ret;
1841 }
1842
1843 static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int origin)
1844 {
1845 struct inode *inode = file->f_mapping->host;
1846 int ret;
1847
1848 mutex_lock(&inode->i_mutex);
1849 switch (origin) {
1850 case SEEK_END:
1851 case SEEK_CUR:
1852 offset = generic_file_llseek(file, offset, origin);
1853 goto out;
1854 case SEEK_DATA:
1855 case SEEK_HOLE:
1856 if (offset >= i_size_read(inode)) {
1857 mutex_unlock(&inode->i_mutex);
1858 return -ENXIO;
1859 }
1860
1861 ret = find_desired_extent(inode, &offset, origin);
1862 if (ret) {
1863 mutex_unlock(&inode->i_mutex);
1864 return ret;
1865 }
1866 }
1867
1868 if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET)) {
1869 offset = -EINVAL;
1870 goto out;
1871 }
1872 if (offset > inode->i_sb->s_maxbytes) {
1873 offset = -EINVAL;
1874 goto out;
1875 }
1876
1877 /* Special lock needed here? */
1878 if (offset != file->f_pos) {
1879 file->f_pos = offset;
1880 file->f_version = 0;
1881 }
1882 out:
1883 mutex_unlock(&inode->i_mutex);
1884 return offset;
1885 }
1886
1887 const struct file_operations btrfs_file_operations = {
1888 .llseek = btrfs_file_llseek,
1889 .read = do_sync_read,
1890 .write = do_sync_write,
1891 .aio_read = generic_file_aio_read,
1892 .splice_read = generic_file_splice_read,
1893 .aio_write = btrfs_file_aio_write,
1894 .mmap = btrfs_file_mmap,
1895 .open = generic_file_open,
1896 .release = btrfs_release_file,
1897 .fsync = btrfs_sync_file,
1898 .fallocate = btrfs_fallocate,
1899 .unlocked_ioctl = btrfs_ioctl,
1900 #ifdef CONFIG_COMPAT
1901 .compat_ioctl = btrfs_ioctl,
1902 #endif
1903 };
Linux kernel - Deliverables
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