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Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm...
[linux-2.6.git] / fs / btrfs / file.c
blob82d0342763c54d652982d2818ab3b9b7f8ffc1ec
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/aio.h>
28 #include <linux/falloc.h>
29 #include <linux/swap.h>
30 #include <linux/writeback.h>
31 #include <linux/statfs.h>
32 #include <linux/compat.h>
33 #include <linux/slab.h>
34 #include <linux/btrfs.h>
35 #include "ctree.h"
36 #include "disk-io.h"
37 #include "transaction.h"
38 #include "btrfs_inode.h"
39 #include "print-tree.h"
40 #include "tree-log.h"
41 #include "locking.h"
42 #include "volumes.h"
43
44 static struct kmem_cache *btrfs_inode_defrag_cachep;
45 /*
46 * when auto defrag is enabled we
47 * queue up these defrag structs to remember which
48 * inodes need defragging passes
49 */
50 struct inode_defrag {
51 struct rb_node rb_node;
52 /* objectid */
53 u64 ino;
54 /*
55 * transid where the defrag was added, we search for
56 * extents newer than this
57 */
58 u64 transid;
59
60 /* root objectid */
61 u64 root;
62
63 /* last offset we were able to defrag */
64 u64 last_offset;
65
66 /* if we've wrapped around back to zero once already */
67 int cycled;
68 };
69
70 static int __compare_inode_defrag(struct inode_defrag *defrag1,
71 struct inode_defrag *defrag2)
72 {
73 if (defrag1->root > defrag2->root)
74 return 1;
75 else if (defrag1->root < defrag2->root)
76 return -1;
77 else if (defrag1->ino > defrag2->ino)
78 return 1;
79 else if (defrag1->ino < defrag2->ino)
80 return -1;
81 else
82 return 0;
83 }
84
85 /* pop a record for an inode into the defrag tree. The lock
86 * must be held already
87 *
88 * If you're inserting a record for an older transid than an
89 * existing record, the transid already in the tree is lowered
90 *
91 * If an existing record is found the defrag item you
92 * pass in is freed
93 */
94 static int __btrfs_add_inode_defrag(struct inode *inode,
95 struct inode_defrag *defrag)
96 {
97 struct btrfs_root *root = BTRFS_I(inode)->root;
98 struct inode_defrag *entry;
99 struct rb_node **p;
100 struct rb_node *parent = NULL;
101 int ret;
102
103 p = &root->fs_info->defrag_inodes.rb_node;
104 while (*p) {
105 parent = *p;
106 entry = rb_entry(parent, struct inode_defrag, rb_node);
107
108 ret = __compare_inode_defrag(defrag, entry);
109 if (ret < 0)
110 p = &parent->rb_left;
111 else if (ret > 0)
112 p = &parent->rb_right;
113 else {
114 /* if we're reinserting an entry for
115 * an old defrag run, make sure to
116 * lower the transid of our existing record
117 */
118 if (defrag->transid < entry->transid)
119 entry->transid = defrag->transid;
120 if (defrag->last_offset > entry->last_offset)
121 entry->last_offset = defrag->last_offset;
122 return -EEXIST;
123 }
124 }
125 set_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
126 rb_link_node(&defrag->rb_node, parent, p);
127 rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes);
128 return 0;
129 }
130
131 static inline int __need_auto_defrag(struct btrfs_root *root)
132 {
133 if (!btrfs_test_opt(root, AUTO_DEFRAG))
134 return 0;
135
136 if (btrfs_fs_closing(root->fs_info))
137 return 0;
138
139 return 1;
140 }
141
142 /*
143 * insert a defrag record for this inode if auto defrag is
144 * enabled
145 */
146 int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
147 struct inode *inode)
148 {
149 struct btrfs_root *root = BTRFS_I(inode)->root;
150 struct inode_defrag *defrag;
151 u64 transid;
152 int ret;
153
154 if (!__need_auto_defrag(root))
155 return 0;
156
157 if (test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags))
158 return 0;
159
160 if (trans)
161 transid = trans->transid;
162 else
163 transid = BTRFS_I(inode)->root->last_trans;
164
165 defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS);
166 if (!defrag)
167 return -ENOMEM;
168
169 defrag->ino = btrfs_ino(inode);
170 defrag->transid = transid;
171 defrag->root = root->root_key.objectid;
172
173 spin_lock(&root->fs_info->defrag_inodes_lock);
174 if (!test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags)) {
175 /*
176 * If we set IN_DEFRAG flag and evict the inode from memory,
177 * and then re-read this inode, this new inode doesn't have
178 * IN_DEFRAG flag. At the case, we may find the existed defrag.
179 */
180 ret = __btrfs_add_inode_defrag(inode, defrag);
181 if (ret)
182 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
183 } else {
184 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
185 }
186 spin_unlock(&root->fs_info->defrag_inodes_lock);
187 return 0;
188 }
189
190 /*
191 * Requeue the defrag object. If there is a defrag object that points to
192 * the same inode in the tree, we will merge them together (by
193 * __btrfs_add_inode_defrag()) and free the one that we want to requeue.
194 */
195 static void btrfs_requeue_inode_defrag(struct inode *inode,
196 struct inode_defrag *defrag)
197 {
198 struct btrfs_root *root = BTRFS_I(inode)->root;
199 int ret;
200
201 if (!__need_auto_defrag(root))
202 goto out;
203
204 /*
205 * Here we don't check the IN_DEFRAG flag, because we need merge
206 * them together.
207 */
208 spin_lock(&root->fs_info->defrag_inodes_lock);
209 ret = __btrfs_add_inode_defrag(inode, defrag);
210 spin_unlock(&root->fs_info->defrag_inodes_lock);
211 if (ret)
212 goto out;
213 return;
214 out:
215 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
216 }
217
218 /*
219 * pick the defragable inode that we want, if it doesn't exist, we will get
220 * the next one.
221 */
222 static struct inode_defrag *
223 btrfs_pick_defrag_inode(struct btrfs_fs_info *fs_info, u64 root, u64 ino)
224 {
225 struct inode_defrag *entry = NULL;
226 struct inode_defrag tmp;
227 struct rb_node *p;
228 struct rb_node *parent = NULL;
229 int ret;
230
231 tmp.ino = ino;
232 tmp.root = root;
233
234 spin_lock(&fs_info->defrag_inodes_lock);
235 p = fs_info->defrag_inodes.rb_node;
236 while (p) {
237 parent = p;
238 entry = rb_entry(parent, struct inode_defrag, rb_node);
239
240 ret = __compare_inode_defrag(&tmp, entry);
241 if (ret < 0)
242 p = parent->rb_left;
243 else if (ret > 0)
244 p = parent->rb_right;
245 else
246 goto out;
247 }
248
249 if (parent && __compare_inode_defrag(&tmp, entry) > 0) {
250 parent = rb_next(parent);
251 if (parent)
252 entry = rb_entry(parent, struct inode_defrag, rb_node);
253 else
254 entry = NULL;
255 }
256 out:
257 if (entry)
258 rb_erase(parent, &fs_info->defrag_inodes);
259 spin_unlock(&fs_info->defrag_inodes_lock);
260 return entry;
261 }
262
263 void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info)
264 {
265 struct inode_defrag *defrag;
266 struct rb_node *node;
267
268 spin_lock(&fs_info->defrag_inodes_lock);
269 node = rb_first(&fs_info->defrag_inodes);
270 while (node) {
271 rb_erase(node, &fs_info->defrag_inodes);
272 defrag = rb_entry(node, struct inode_defrag, rb_node);
273 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
274
275 if (need_resched()) {
276 spin_unlock(&fs_info->defrag_inodes_lock);
277 cond_resched();
278 spin_lock(&fs_info->defrag_inodes_lock);
279 }
280
281 node = rb_first(&fs_info->defrag_inodes);
282 }
283 spin_unlock(&fs_info->defrag_inodes_lock);
284 }
285
286 #define BTRFS_DEFRAG_BATCH 1024
287
288 static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
289 struct inode_defrag *defrag)
290 {
291 struct btrfs_root *inode_root;
292 struct inode *inode;
293 struct btrfs_key key;
294 struct btrfs_ioctl_defrag_range_args range;
295 int num_defrag;
296 int index;
297 int ret;
298
299 /* get the inode */
300 key.objectid = defrag->root;
301 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
302 key.offset = (u64)-1;
303
304 index = srcu_read_lock(&fs_info->subvol_srcu);
305
306 inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
307 if (IS_ERR(inode_root)) {
308 ret = PTR_ERR(inode_root);
309 goto cleanup;
310 }
311
312 key.objectid = defrag->ino;
313 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
314 key.offset = 0;
315 inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
316 if (IS_ERR(inode)) {
317 ret = PTR_ERR(inode);
318 goto cleanup;
319 }
320 srcu_read_unlock(&fs_info->subvol_srcu, index);
321
322 /* do a chunk of defrag */
323 clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
324 memset(&range, 0, sizeof(range));
325 range.len = (u64)-1;
326 range.start = defrag->last_offset;
327
328 sb_start_write(fs_info->sb);
329 num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
330 BTRFS_DEFRAG_BATCH);
331 sb_end_write(fs_info->sb);
332 /*
333 * if we filled the whole defrag batch, there
334 * must be more work to do. Queue this defrag
335 * again
336 */
337 if (num_defrag == BTRFS_DEFRAG_BATCH) {
338 defrag->last_offset = range.start;
339 btrfs_requeue_inode_defrag(inode, defrag);
340 } else if (defrag->last_offset && !defrag->cycled) {
341 /*
342 * we didn't fill our defrag batch, but
343 * we didn't start at zero. Make sure we loop
344 * around to the start of the file.
345 */
346 defrag->last_offset = 0;
347 defrag->cycled = 1;
348 btrfs_requeue_inode_defrag(inode, defrag);
349 } else {
350 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
351 }
352
353 iput(inode);
354 return 0;
355 cleanup:
356 srcu_read_unlock(&fs_info->subvol_srcu, index);
357 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
358 return ret;
359 }
360
361 /*
362 * run through the list of inodes in the FS that need
363 * defragging
364 */
365 int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
366 {
367 struct inode_defrag *defrag;
368 u64 first_ino = 0;
369 u64 root_objectid = 0;
370
371 atomic_inc(&fs_info->defrag_running);
372 while (1) {
373 /* Pause the auto defragger. */
374 if (test_bit(BTRFS_FS_STATE_REMOUNTING,
375 &fs_info->fs_state))
376 break;
377
378 if (!__need_auto_defrag(fs_info->tree_root))
379 break;
380
381 /* find an inode to defrag */
382 defrag = btrfs_pick_defrag_inode(fs_info, root_objectid,
383 first_ino);
384 if (!defrag) {
385 if (root_objectid || first_ino) {
386 root_objectid = 0;
387 first_ino = 0;
388 continue;
389 } else {
390 break;
391 }
392 }
393
394 first_ino = defrag->ino + 1;
395 root_objectid = defrag->root;
396
397 __btrfs_run_defrag_inode(fs_info, defrag);
398 }
399 atomic_dec(&fs_info->defrag_running);
400
401 /*
402 * during unmount, we use the transaction_wait queue to
403 * wait for the defragger to stop
404 */
405 wake_up(&fs_info->transaction_wait);
406 return 0;
407 }
408
409 /* simple helper to fault in pages and copy. This should go away
410 * and be replaced with calls into generic code.
411 */
412 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
413 size_t write_bytes,
414 struct page **prepared_pages,
415 struct iov_iter *i)
416 {
417 size_t copied = 0;
418 size_t total_copied = 0;
419 int pg = 0;
420 int offset = pos & (PAGE_CACHE_SIZE - 1);
421
422 while (write_bytes > 0) {
423 size_t count = min_t(size_t,
424 PAGE_CACHE_SIZE - offset, write_bytes);
425 struct page *page = prepared_pages[pg];
426 /*
427 * Copy data from userspace to the current page
428 *
429 * Disable pagefault to avoid recursive lock since
430 * the pages are already locked
431 */
432 pagefault_disable();
433 copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
434 pagefault_enable();
435
436 /* Flush processor's dcache for this page */
437 flush_dcache_page(page);
438
439 /*
440 * if we get a partial write, we can end up with
441 * partially up to date pages. These add
442 * a lot of complexity, so make sure they don't
443 * happen by forcing this copy to be retried.
444 *
445 * The rest of the btrfs_file_write code will fall
446 * back to page at a time copies after we return 0.
447 */
448 if (!PageUptodate(page) && copied < count)
449 copied = 0;
450
451 iov_iter_advance(i, copied);
452 write_bytes -= copied;
453 total_copied += copied;
454
455 /* Return to btrfs_file_aio_write to fault page */
456 if (unlikely(copied == 0))
457 break;
458
459 if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
460 offset += copied;
461 } else {
462 pg++;
463 offset = 0;
464 }
465 }
466 return total_copied;
467 }
468
469 /*
470 * unlocks pages after btrfs_file_write is done with them
471 */
472 static void btrfs_drop_pages(struct page **pages, size_t num_pages)
473 {
474 size_t i;
475 for (i = 0; i < num_pages; i++) {
476 /* page checked is some magic around finding pages that
477 * have been modified without going through btrfs_set_page_dirty
478 * clear it here
479 */
480 ClearPageChecked(pages[i]);
481 unlock_page(pages[i]);
482 mark_page_accessed(pages[i]);
483 page_cache_release(pages[i]);
484 }
485 }
486
487 /*
488 * after copy_from_user, pages need to be dirtied and we need to make
489 * sure holes are created between the current EOF and the start of
490 * any next extents (if required).
491 *
492 * this also makes the decision about creating an inline extent vs
493 * doing real data extents, marking pages dirty and delalloc as required.
494 */
495 int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
496 struct page **pages, size_t num_pages,
497 loff_t pos, size_t write_bytes,
498 struct extent_state **cached)
499 {
500 int err = 0;
501 int i;
502 u64 num_bytes;
503 u64 start_pos;
504 u64 end_of_last_block;
505 u64 end_pos = pos + write_bytes;
506 loff_t isize = i_size_read(inode);
507
508 start_pos = pos & ~((u64)root->sectorsize - 1);
509 num_bytes = ALIGN(write_bytes + pos - start_pos, root->sectorsize);
510
511 end_of_last_block = start_pos + num_bytes - 1;
512 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
513 cached);
514 if (err)
515 return err;
516
517 for (i = 0; i < num_pages; i++) {
518 struct page *p = pages[i];
519 SetPageUptodate(p);
520 ClearPageChecked(p);
521 set_page_dirty(p);
522 }
523
524 /*
525 * we've only changed i_size in ram, and we haven't updated
526 * the disk i_size. There is no need to log the inode
527 * at this time.
528 */
529 if (end_pos > isize)
530 i_size_write(inode, end_pos);
531 return 0;
532 }
533
534 /*
535 * this drops all the extents in the cache that intersect the range
536 * [start, end]. Existing extents are split as required.
537 */
538 void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
539 int skip_pinned)
540 {
541 struct extent_map *em;
542 struct extent_map *split = NULL;
543 struct extent_map *split2 = NULL;
544 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
545 u64 len = end - start + 1;
546 u64 gen;
547 int ret;
548 int testend = 1;
549 unsigned long flags;
550 int compressed = 0;
551 bool modified;
552
553 WARN_ON(end < start);
554 if (end == (u64)-1) {
555 len = (u64)-1;
556 testend = 0;
557 }
558 while (1) {
559 int no_splits = 0;
560
561 modified = false;
562 if (!split)
563 split = alloc_extent_map();
564 if (!split2)
565 split2 = alloc_extent_map();
566 if (!split || !split2)
567 no_splits = 1;
568
569 write_lock(&em_tree->lock);
570 em = lookup_extent_mapping(em_tree, start, len);
571 if (!em) {
572 write_unlock(&em_tree->lock);
573 break;
574 }
575 flags = em->flags;
576 gen = em->generation;
577 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
578 if (testend && em->start + em->len >= start + len) {
579 free_extent_map(em);
580 write_unlock(&em_tree->lock);
581 break;
582 }
583 start = em->start + em->len;
584 if (testend)
585 len = start + len - (em->start + em->len);
586 free_extent_map(em);
587 write_unlock(&em_tree->lock);
588 continue;
589 }
590 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
591 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
592 clear_bit(EXTENT_FLAG_LOGGING, &flags);
593 modified = !list_empty(&em->list);
594 remove_extent_mapping(em_tree, em);
595 if (no_splits)
596 goto next;
597
598 if (em->start < start) {
599 split->start = em->start;
600 split->len = start - em->start;
601
602 if (em->block_start < EXTENT_MAP_LAST_BYTE) {
603 split->orig_start = em->orig_start;
604 split->block_start = em->block_start;
605
606 if (compressed)
607 split->block_len = em->block_len;
608 else
609 split->block_len = split->len;
610 split->orig_block_len = max(split->block_len,
611 em->orig_block_len);
612 split->ram_bytes = em->ram_bytes;
613 } else {
614 split->orig_start = split->start;
615 split->block_len = 0;
616 split->block_start = em->block_start;
617 split->orig_block_len = 0;
618 split->ram_bytes = split->len;
619 }
620
621 split->generation = gen;
622 split->bdev = em->bdev;
623 split->flags = flags;
624 split->compress_type = em->compress_type;
625 ret = add_extent_mapping(em_tree, split, modified);
626 BUG_ON(ret); /* Logic error */
627 free_extent_map(split);
628 split = split2;
629 split2 = NULL;
630 }
631 if (testend && em->start + em->len > start + len) {
632 u64 diff = start + len - em->start;
633
634 split->start = start + len;
635 split->len = em->start + em->len - (start + len);
636 split->bdev = em->bdev;
637 split->flags = flags;
638 split->compress_type = em->compress_type;
639 split->generation = gen;
640
641 if (em->block_start < EXTENT_MAP_LAST_BYTE) {
642 split->orig_block_len = max(em->block_len,
643 em->orig_block_len);
644
645 split->ram_bytes = em->ram_bytes;
646 if (compressed) {
647 split->block_len = em->block_len;
648 split->block_start = em->block_start;
649 split->orig_start = em->orig_start;
650 } else {
651 split->block_len = split->len;
652 split->block_start = em->block_start
653 + diff;
654 split->orig_start = em->orig_start;
655 }
656 } else {
657 split->ram_bytes = split->len;
658 split->orig_start = split->start;
659 split->block_len = 0;
660 split->block_start = em->block_start;
661 split->orig_block_len = 0;
662 }
663
664 ret = add_extent_mapping(em_tree, split, modified);
665 BUG_ON(ret); /* Logic error */
666 free_extent_map(split);
667 split = NULL;
668 }
669 next:
670 write_unlock(&em_tree->lock);
671
672 /* once for us */
673 free_extent_map(em);
674 /* once for the tree*/
675 free_extent_map(em);
676 }
677 if (split)
678 free_extent_map(split);
679 if (split2)
680 free_extent_map(split2);
681 }
682
683 /*
684 * this is very complex, but the basic idea is to drop all extents
685 * in the range start - end. hint_block is filled in with a block number
686 * that would be a good hint to the block allocator for this file.
687 *
688 * If an extent intersects the range but is not entirely inside the range
689 * it is either truncated or split. Anything entirely inside the range
690 * is deleted from the tree.
691 */
692 int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
693 struct btrfs_root *root, struct inode *inode,
694 struct btrfs_path *path, u64 start, u64 end,
695 u64 *drop_end, int drop_cache)
696 {
697 struct extent_buffer *leaf;
698 struct btrfs_file_extent_item *fi;
699 struct btrfs_key key;
700 struct btrfs_key new_key;
701 u64 ino = btrfs_ino(inode);
702 u64 search_start = start;
703 u64 disk_bytenr = 0;
704 u64 num_bytes = 0;
705 u64 extent_offset = 0;
706 u64 extent_end = 0;
707 int del_nr = 0;
708 int del_slot = 0;
709 int extent_type;
710 int recow;
711 int ret;
712 int modify_tree = -1;
713 int update_refs = (root->ref_cows || root == root->fs_info->tree_root);
714 int found = 0;
715
716 if (drop_cache)
717 btrfs_drop_extent_cache(inode, start, end - 1, 0);
718
719 if (start >= BTRFS_I(inode)->disk_i_size)
720 modify_tree = 0;
721
722 while (1) {
723 recow = 0;
724 ret = btrfs_lookup_file_extent(trans, root, path, ino,
725 search_start, modify_tree);
726 if (ret < 0)
727 break;
728 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
729 leaf = path->nodes[0];
730 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
731 if (key.objectid == ino &&
732 key.type == BTRFS_EXTENT_DATA_KEY)
733 path->slots[0]--;
734 }
735 ret = 0;
736 next_slot:
737 leaf = path->nodes[0];
738 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
739 BUG_ON(del_nr > 0);
740 ret = btrfs_next_leaf(root, path);
741 if (ret < 0)
742 break;
743 if (ret > 0) {
744 ret = 0;
745 break;
746 }
747 leaf = path->nodes[0];
748 recow = 1;
749 }
750
751 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
752 if (key.objectid > ino ||
753 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
754 break;
755
756 fi = btrfs_item_ptr(leaf, path->slots[0],
757 struct btrfs_file_extent_item);
758 extent_type = btrfs_file_extent_type(leaf, fi);
759
760 if (extent_type == BTRFS_FILE_EXTENT_REG ||
761 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
762 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
763 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
764 extent_offset = btrfs_file_extent_offset(leaf, fi);
765 extent_end = key.offset +
766 btrfs_file_extent_num_bytes(leaf, fi);
767 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
768 extent_end = key.offset +
769 btrfs_file_extent_inline_len(leaf, fi);
770 } else {
771 WARN_ON(1);
772 extent_end = search_start;
773 }
774
775 if (extent_end <= search_start) {
776 path->slots[0]++;
777 goto next_slot;
778 }
779
780 found = 1;
781 search_start = max(key.offset, start);
782 if (recow || !modify_tree) {
783 modify_tree = -1;
784 btrfs_release_path(path);
785 continue;
786 }
787
788 /*
789 * | - range to drop - |
790 * | -------- extent -------- |
791 */
792 if (start > key.offset && end < extent_end) {
793 BUG_ON(del_nr > 0);
794 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
795
796 memcpy(&new_key, &key, sizeof(new_key));
797 new_key.offset = start;
798 ret = btrfs_duplicate_item(trans, root, path,
799 &new_key);
800 if (ret == -EAGAIN) {
801 btrfs_release_path(path);
802 continue;
803 }
804 if (ret < 0)
805 break;
806
807 leaf = path->nodes[0];
808 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
809 struct btrfs_file_extent_item);
810 btrfs_set_file_extent_num_bytes(leaf, fi,
811 start - key.offset);
812
813 fi = btrfs_item_ptr(leaf, path->slots[0],
814 struct btrfs_file_extent_item);
815
816 extent_offset += start - key.offset;
817 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
818 btrfs_set_file_extent_num_bytes(leaf, fi,
819 extent_end - start);
820 btrfs_mark_buffer_dirty(leaf);
821
822 if (update_refs && disk_bytenr > 0) {
823 ret = btrfs_inc_extent_ref(trans, root,
824 disk_bytenr, num_bytes, 0,
825 root->root_key.objectid,
826 new_key.objectid,
827 start - extent_offset, 0);
828 BUG_ON(ret); /* -ENOMEM */
829 }
830 key.offset = start;
831 }
832 /*
833 * | ---- range to drop ----- |
834 * | -------- extent -------- |
835 */
836 if (start <= key.offset && end < extent_end) {
837 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
838
839 memcpy(&new_key, &key, sizeof(new_key));
840 new_key.offset = end;
841 btrfs_set_item_key_safe(root, path, &new_key);
842
843 extent_offset += end - key.offset;
844 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
845 btrfs_set_file_extent_num_bytes(leaf, fi,
846 extent_end - end);
847 btrfs_mark_buffer_dirty(leaf);
848 if (update_refs && disk_bytenr > 0)
849 inode_sub_bytes(inode, end - key.offset);
850 break;
851 }
852
853 search_start = extent_end;
854 /*
855 * | ---- range to drop ----- |
856 * | -------- extent -------- |
857 */
858 if (start > key.offset && end >= extent_end) {
859 BUG_ON(del_nr > 0);
860 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
861
862 btrfs_set_file_extent_num_bytes(leaf, fi,
863 start - key.offset);
864 btrfs_mark_buffer_dirty(leaf);
865 if (update_refs && disk_bytenr > 0)
866 inode_sub_bytes(inode, extent_end - start);
867 if (end == extent_end)
868 break;
869
870 path->slots[0]++;
871 goto next_slot;
872 }
873
874 /*
875 * | ---- range to drop ----- |
876 * | ------ extent ------ |
877 */
878 if (start <= key.offset && end >= extent_end) {
879 if (del_nr == 0) {
880 del_slot = path->slots[0];
881 del_nr = 1;
882 } else {
883 BUG_ON(del_slot + del_nr != path->slots[0]);
884 del_nr++;
885 }
886
887 if (update_refs &&
888 extent_type == BTRFS_FILE_EXTENT_INLINE) {
889 inode_sub_bytes(inode,
890 extent_end - key.offset);
891 extent_end = ALIGN(extent_end,
892 root->sectorsize);
893 } else if (update_refs && disk_bytenr > 0) {
894 ret = btrfs_free_extent(trans, root,
895 disk_bytenr, num_bytes, 0,
896 root->root_key.objectid,
897 key.objectid, key.offset -
898 extent_offset, 0);
899 BUG_ON(ret); /* -ENOMEM */
900 inode_sub_bytes(inode,
901 extent_end - key.offset);
902 }
903
904 if (end == extent_end)
905 break;
906
907 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
908 path->slots[0]++;
909 goto next_slot;
910 }
911
912 ret = btrfs_del_items(trans, root, path, del_slot,
913 del_nr);
914 if (ret) {
915 btrfs_abort_transaction(trans, root, ret);
916 break;
917 }
918
919 del_nr = 0;
920 del_slot = 0;
921
922 btrfs_release_path(path);
923 continue;
924 }
925
926 BUG_ON(1);
927 }
928
929 if (!ret && del_nr > 0) {
930 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
931 if (ret)
932 btrfs_abort_transaction(trans, root, ret);
933 }
934
935 if (drop_end)
936 *drop_end = found ? min(end, extent_end) : end;
937 btrfs_release_path(path);
938 return ret;
939 }
940
941 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
942 struct btrfs_root *root, struct inode *inode, u64 start,
943 u64 end, int drop_cache)
944 {
945 struct btrfs_path *path;
946 int ret;
947
948 path = btrfs_alloc_path();
949 if (!path)
950 return -ENOMEM;
951 ret = __btrfs_drop_extents(trans, root, inode, path, start, end, NULL,
952 drop_cache);
953 btrfs_free_path(path);
954 return ret;
955 }
956
957 static int extent_mergeable(struct extent_buffer *leaf, int slot,
958 u64 objectid, u64 bytenr, u64 orig_offset,
959 u64 *start, u64 *end)
960 {
961 struct btrfs_file_extent_item *fi;
962 struct btrfs_key key;
963 u64 extent_end;
964
965 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
966 return 0;
967
968 btrfs_item_key_to_cpu(leaf, &key, slot);
969 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
970 return 0;
971
972 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
973 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
974 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
975 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
976 btrfs_file_extent_compression(leaf, fi) ||
977 btrfs_file_extent_encryption(leaf, fi) ||
978 btrfs_file_extent_other_encoding(leaf, fi))
979 return 0;
980
981 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
982 if ((*start && *start != key.offset) || (*end && *end != extent_end))
983 return 0;
984
985 *start = key.offset;
986 *end = extent_end;
987 return 1;
988 }
989
990 /*
991 * Mark extent in the range start - end as written.
992 *
993 * This changes extent type from 'pre-allocated' to 'regular'. If only
994 * part of extent is marked as written, the extent will be split into
995 * two or three.
996 */
997 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
998 struct inode *inode, u64 start, u64 end)
999 {
1000 struct btrfs_root *root = BTRFS_I(inode)->root;
1001 struct extent_buffer *leaf;
1002 struct btrfs_path *path;
1003 struct btrfs_file_extent_item *fi;
1004 struct btrfs_key key;
1005 struct btrfs_key new_key;
1006 u64 bytenr;
1007 u64 num_bytes;
1008 u64 extent_end;
1009 u64 orig_offset;
1010 u64 other_start;
1011 u64 other_end;
1012 u64 split;
1013 int del_nr = 0;
1014 int del_slot = 0;
1015 int recow;
1016 int ret;
1017 u64 ino = btrfs_ino(inode);
1018
1019 path = btrfs_alloc_path();
1020 if (!path)
1021 return -ENOMEM;
1022 again:
1023 recow = 0;
1024 split = start;
1025 key.objectid = ino;
1026 key.type = BTRFS_EXTENT_DATA_KEY;
1027 key.offset = split;
1028
1029 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1030 if (ret < 0)
1031 goto out;
1032 if (ret > 0 && path->slots[0] > 0)
1033 path->slots[0]--;
1034
1035 leaf = path->nodes[0];
1036 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1037 BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
1038 fi = btrfs_item_ptr(leaf, path->slots[0],
1039 struct btrfs_file_extent_item);
1040 BUG_ON(btrfs_file_extent_type(leaf, fi) !=
1041 BTRFS_FILE_EXTENT_PREALLOC);
1042 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1043 BUG_ON(key.offset > start || extent_end < end);
1044
1045 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1046 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1047 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
1048 memcpy(&new_key, &key, sizeof(new_key));
1049
1050 if (start == key.offset && end < extent_end) {
1051 other_start = 0;
1052 other_end = start;
1053 if (extent_mergeable(leaf, path->slots[0] - 1,
1054 ino, bytenr, orig_offset,
1055 &other_start, &other_end)) {
1056 new_key.offset = end;
1057 btrfs_set_item_key_safe(root, path, &new_key);
1058 fi = btrfs_item_ptr(leaf, path->slots[0],
1059 struct btrfs_file_extent_item);
1060 btrfs_set_file_extent_generation(leaf, fi,
1061 trans->transid);
1062 btrfs_set_file_extent_num_bytes(leaf, fi,
1063 extent_end - end);
1064 btrfs_set_file_extent_offset(leaf, fi,
1065 end - orig_offset);
1066 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1067 struct btrfs_file_extent_item);
1068 btrfs_set_file_extent_generation(leaf, fi,
1069 trans->transid);
1070 btrfs_set_file_extent_num_bytes(leaf, fi,
1071 end - other_start);
1072 btrfs_mark_buffer_dirty(leaf);
1073 goto out;
1074 }
1075 }
1076
1077 if (start > key.offset && end == extent_end) {
1078 other_start = end;
1079 other_end = 0;
1080 if (extent_mergeable(leaf, path->slots[0] + 1,
1081 ino, bytenr, orig_offset,
1082 &other_start, &other_end)) {
1083 fi = btrfs_item_ptr(leaf, path->slots[0],
1084 struct btrfs_file_extent_item);
1085 btrfs_set_file_extent_num_bytes(leaf, fi,
1086 start - key.offset);
1087 btrfs_set_file_extent_generation(leaf, fi,
1088 trans->transid);
1089 path->slots[0]++;
1090 new_key.offset = start;
1091 btrfs_set_item_key_safe(root, path, &new_key);
1092
1093 fi = btrfs_item_ptr(leaf, path->slots[0],
1094 struct btrfs_file_extent_item);
1095 btrfs_set_file_extent_generation(leaf, fi,
1096 trans->transid);
1097 btrfs_set_file_extent_num_bytes(leaf, fi,
1098 other_end - start);
1099 btrfs_set_file_extent_offset(leaf, fi,
1100 start - orig_offset);
1101 btrfs_mark_buffer_dirty(leaf);
1102 goto out;
1103 }
1104 }
1105
1106 while (start > key.offset || end < extent_end) {
1107 if (key.offset == start)
1108 split = end;
1109
1110 new_key.offset = split;
1111 ret = btrfs_duplicate_item(trans, root, path, &new_key);
1112 if (ret == -EAGAIN) {
1113 btrfs_release_path(path);
1114 goto again;
1115 }
1116 if (ret < 0) {
1117 btrfs_abort_transaction(trans, root, ret);
1118 goto out;
1119 }
1120
1121 leaf = path->nodes[0];
1122 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1123 struct btrfs_file_extent_item);
1124 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1125 btrfs_set_file_extent_num_bytes(leaf, fi,
1126 split - key.offset);
1127
1128 fi = btrfs_item_ptr(leaf, path->slots[0],
1129 struct btrfs_file_extent_item);
1130
1131 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1132 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
1133 btrfs_set_file_extent_num_bytes(leaf, fi,
1134 extent_end - split);
1135 btrfs_mark_buffer_dirty(leaf);
1136
1137 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
1138 root->root_key.objectid,
1139 ino, orig_offset, 0);
1140 BUG_ON(ret); /* -ENOMEM */
1141
1142 if (split == start) {
1143 key.offset = start;
1144 } else {
1145 BUG_ON(start != key.offset);
1146 path->slots[0]--;
1147 extent_end = end;
1148 }
1149 recow = 1;
1150 }
1151
1152 other_start = end;
1153 other_end = 0;
1154 if (extent_mergeable(leaf, path->slots[0] + 1,
1155 ino, bytenr, orig_offset,
1156 &other_start, &other_end)) {
1157 if (recow) {
1158 btrfs_release_path(path);
1159 goto again;
1160 }
1161 extent_end = other_end;
1162 del_slot = path->slots[0] + 1;
1163 del_nr++;
1164 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1165 0, root->root_key.objectid,
1166 ino, orig_offset, 0);
1167 BUG_ON(ret); /* -ENOMEM */
1168 }
1169 other_start = 0;
1170 other_end = start;
1171 if (extent_mergeable(leaf, path->slots[0] - 1,
1172 ino, bytenr, orig_offset,
1173 &other_start, &other_end)) {
1174 if (recow) {
1175 btrfs_release_path(path);
1176 goto again;
1177 }
1178 key.offset = other_start;
1179 del_slot = path->slots[0];
1180 del_nr++;
1181 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1182 0, root->root_key.objectid,
1183 ino, orig_offset, 0);
1184 BUG_ON(ret); /* -ENOMEM */
1185 }
1186 if (del_nr == 0) {
1187 fi = btrfs_item_ptr(leaf, path->slots[0],
1188 struct btrfs_file_extent_item);
1189 btrfs_set_file_extent_type(leaf, fi,
1190 BTRFS_FILE_EXTENT_REG);
1191 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1192 btrfs_mark_buffer_dirty(leaf);
1193 } else {
1194 fi = btrfs_item_ptr(leaf, del_slot - 1,
1195 struct btrfs_file_extent_item);
1196 btrfs_set_file_extent_type(leaf, fi,
1197 BTRFS_FILE_EXTENT_REG);
1198 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1199 btrfs_set_file_extent_num_bytes(leaf, fi,
1200 extent_end - key.offset);
1201 btrfs_mark_buffer_dirty(leaf);
1202
1203 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1204 if (ret < 0) {
1205 btrfs_abort_transaction(trans, root, ret);
1206 goto out;
1207 }
1208 }
1209 out:
1210 btrfs_free_path(path);
1211 return 0;
1212 }
1213
1214 /*
1215 * on error we return an unlocked page and the error value
1216 * on success we return a locked page and 0
1217 */
1218 static int prepare_uptodate_page(struct page *page, u64 pos,
1219 bool force_uptodate)
1220 {
1221 int ret = 0;
1222
1223 if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) &&
1224 !PageUptodate(page)) {
1225 ret = btrfs_readpage(NULL, page);
1226 if (ret)
1227 return ret;
1228 lock_page(page);
1229 if (!PageUptodate(page)) {
1230 unlock_page(page);
1231 return -EIO;
1232 }
1233 }
1234 return 0;
1235 }
1236
1237 /*
1238 * this gets pages into the page cache and locks them down, it also properly
1239 * waits for data=ordered extents to finish before allowing the pages to be
1240 * modified.
1241 */
1242 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
1243 struct page **pages, size_t num_pages,
1244 loff_t pos, unsigned long first_index,
1245 size_t write_bytes, bool force_uptodate)
1246 {
1247 struct extent_state *cached_state = NULL;
1248 int i;
1249 unsigned long index = pos >> PAGE_CACHE_SHIFT;
1250 struct inode *inode = file_inode(file);
1251 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1252 int err = 0;
1253 int faili = 0;
1254 u64 start_pos;
1255 u64 last_pos;
1256
1257 start_pos = pos & ~((u64)root->sectorsize - 1);
1258 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
1259
1260 again:
1261 for (i = 0; i < num_pages; i++) {
1262 pages[i] = find_or_create_page(inode->i_mapping, index + i,
1263 mask | __GFP_WRITE);
1264 if (!pages[i]) {
1265 faili = i - 1;
1266 err = -ENOMEM;
1267 goto fail;
1268 }
1269
1270 if (i == 0)
1271 err = prepare_uptodate_page(pages[i], pos,
1272 force_uptodate);
1273 if (i == num_pages - 1)
1274 err = prepare_uptodate_page(pages[i],
1275 pos + write_bytes, false);
1276 if (err) {
1277 page_cache_release(pages[i]);
1278 faili = i - 1;
1279 goto fail;
1280 }
1281 wait_on_page_writeback(pages[i]);
1282 }
1283 faili = num_pages - 1;
1284 err = 0;
1285 if (start_pos < inode->i_size) {
1286 struct btrfs_ordered_extent *ordered;
1287 lock_extent_bits(&BTRFS_I(inode)->io_tree,
1288 start_pos, last_pos - 1, 0, &cached_state);
1289 ordered = btrfs_lookup_first_ordered_extent(inode,
1290 last_pos - 1);
1291 if (ordered &&
1292 ordered->file_offset + ordered->len > start_pos &&
1293 ordered->file_offset < last_pos) {
1294 btrfs_put_ordered_extent(ordered);
1295 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1296 start_pos, last_pos - 1,
1297 &cached_state, GFP_NOFS);
1298 for (i = 0; i < num_pages; i++) {
1299 unlock_page(pages[i]);
1300 page_cache_release(pages[i]);
1301 }
1302 err = btrfs_wait_ordered_range(inode, start_pos,
1303 last_pos - start_pos);
1304 if (err)
1305 goto fail;
1306 goto again;
1307 }
1308 if (ordered)
1309 btrfs_put_ordered_extent(ordered);
1310
1311 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
1312 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1313 EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
1314 0, 0, &cached_state, GFP_NOFS);
1315 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1316 start_pos, last_pos - 1, &cached_state,
1317 GFP_NOFS);
1318 }
1319 for (i = 0; i < num_pages; i++) {
1320 if (clear_page_dirty_for_io(pages[i]))
1321 account_page_redirty(pages[i]);
1322 set_page_extent_mapped(pages[i]);
1323 WARN_ON(!PageLocked(pages[i]));
1324 }
1325 return 0;
1326 fail:
1327 while (faili >= 0) {
1328 unlock_page(pages[faili]);
1329 page_cache_release(pages[faili]);
1330 faili--;
1331 }
1332 return err;
1333
1334 }
1335
1336 static noinline int check_can_nocow(struct inode *inode, loff_t pos,
1337 size_t *write_bytes)
1338 {
1339 struct btrfs_root *root = BTRFS_I(inode)->root;
1340 struct btrfs_ordered_extent *ordered;
1341 u64 lockstart, lockend;
1342 u64 num_bytes;
1343 int ret;
1344
1345 lockstart = round_down(pos, root->sectorsize);
1346 lockend = lockstart + round_up(*write_bytes, root->sectorsize) - 1;
1347
1348 while (1) {
1349 lock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1350 ordered = btrfs_lookup_ordered_range(inode, lockstart,
1351 lockend - lockstart + 1);
1352 if (!ordered) {
1353 break;
1354 }
1355 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1356 btrfs_start_ordered_extent(inode, ordered, 1);
1357 btrfs_put_ordered_extent(ordered);
1358 }
1359
1360 num_bytes = lockend - lockstart + 1;
1361 ret = can_nocow_extent(inode, lockstart, &num_bytes, NULL, NULL, NULL);
1362 if (ret <= 0) {
1363 ret = 0;
1364 } else {
1365 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
1366 EXTENT_DIRTY | EXTENT_DELALLOC |
1367 EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 0, 0,
1368 NULL, GFP_NOFS);
1369 *write_bytes = min_t(size_t, *write_bytes, num_bytes);
1370 }
1371
1372 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1373
1374 return ret;
1375 }
1376
1377 static noinline ssize_t __btrfs_buffered_write(struct file *file,
1378 struct iov_iter *i,
1379 loff_t pos)
1380 {
1381 struct inode *inode = file_inode(file);
1382 struct btrfs_root *root = BTRFS_I(inode)->root;
1383 struct page **pages = NULL;
1384 u64 release_bytes = 0;
1385 unsigned long first_index;
1386 size_t num_written = 0;
1387 int nrptrs;
1388 int ret = 0;
1389 bool only_release_metadata = false;
1390 bool force_page_uptodate = false;
1391
1392 nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
1393 PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
1394 (sizeof(struct page *)));
1395 nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
1396 nrptrs = max(nrptrs, 8);
1397 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1398 if (!pages)
1399 return -ENOMEM;
1400
1401 first_index = pos >> PAGE_CACHE_SHIFT;
1402
1403 while (iov_iter_count(i) > 0) {
1404 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1405 size_t write_bytes = min(iov_iter_count(i),
1406 nrptrs * (size_t)PAGE_CACHE_SIZE -
1407 offset);
1408 size_t num_pages = (write_bytes + offset +
1409 PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1410 size_t reserve_bytes;
1411 size_t dirty_pages;
1412 size_t copied;
1413
1414 WARN_ON(num_pages > nrptrs);
1415
1416 /*
1417 * Fault pages before locking them in prepare_pages
1418 * to avoid recursive lock
1419 */
1420 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1421 ret = -EFAULT;
1422 break;
1423 }
1424
1425 reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
1426 ret = btrfs_check_data_free_space(inode, reserve_bytes);
1427 if (ret == -ENOSPC &&
1428 (BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
1429 BTRFS_INODE_PREALLOC))) {
1430 ret = check_can_nocow(inode, pos, &write_bytes);
1431 if (ret > 0) {
1432 only_release_metadata = true;
1433 /*
1434 * our prealloc extent may be smaller than
1435 * write_bytes, so scale down.
1436 */
1437 num_pages = (write_bytes + offset +
1438 PAGE_CACHE_SIZE - 1) >>
1439 PAGE_CACHE_SHIFT;
1440 reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
1441 ret = 0;
1442 } else {
1443 ret = -ENOSPC;
1444 }
1445 }
1446
1447 if (ret)
1448 break;
1449
1450 ret = btrfs_delalloc_reserve_metadata(inode, reserve_bytes);
1451 if (ret) {
1452 if (!only_release_metadata)
1453 btrfs_free_reserved_data_space(inode,
1454 reserve_bytes);
1455 break;
1456 }
1457
1458 release_bytes = reserve_bytes;
1459
1460 /*
1461 * This is going to setup the pages array with the number of
1462 * pages we want, so we don't really need to worry about the
1463 * contents of pages from loop to loop
1464 */
1465 ret = prepare_pages(root, file, pages, num_pages,
1466 pos, first_index, write_bytes,
1467 force_page_uptodate);
1468 if (ret)
1469 break;
1470
1471 copied = btrfs_copy_from_user(pos, num_pages,
1472 write_bytes, pages, i);
1473
1474 /*
1475 * if we have trouble faulting in the pages, fall
1476 * back to one page at a time
1477 */
1478 if (copied < write_bytes)
1479 nrptrs = 1;
1480
1481 if (copied == 0) {
1482 force_page_uptodate = true;
1483 dirty_pages = 0;
1484 } else {
1485 force_page_uptodate = false;
1486 dirty_pages = (copied + offset +
1487 PAGE_CACHE_SIZE - 1) >>
1488 PAGE_CACHE_SHIFT;
1489 }
1490
1491 /*
1492 * If we had a short copy we need to release the excess delaloc
1493 * bytes we reserved. We need to increment outstanding_extents
1494 * because btrfs_delalloc_release_space will decrement it, but
1495 * we still have an outstanding extent for the chunk we actually
1496 * managed to copy.
1497 */
1498 if (num_pages > dirty_pages) {
1499 release_bytes = (num_pages - dirty_pages) <<
1500 PAGE_CACHE_SHIFT;
1501 if (copied > 0) {
1502 spin_lock(&BTRFS_I(inode)->lock);
1503 BTRFS_I(inode)->outstanding_extents++;
1504 spin_unlock(&BTRFS_I(inode)->lock);
1505 }
1506 if (only_release_metadata)
1507 btrfs_delalloc_release_metadata(inode,
1508 release_bytes);
1509 else
1510 btrfs_delalloc_release_space(inode,
1511 release_bytes);
1512 }
1513
1514 release_bytes = dirty_pages << PAGE_CACHE_SHIFT;
1515 if (copied > 0) {
1516 ret = btrfs_dirty_pages(root, inode, pages,
1517 dirty_pages, pos, copied,
1518 NULL);
1519 if (ret) {
1520 btrfs_drop_pages(pages, num_pages);
1521 break;
1522 }
1523 }
1524
1525 release_bytes = 0;
1526 btrfs_drop_pages(pages, num_pages);
1527
1528 if (only_release_metadata && copied > 0) {
1529 u64 lockstart = round_down(pos, root->sectorsize);
1530 u64 lockend = lockstart +
1531 (dirty_pages << PAGE_CACHE_SHIFT) - 1;
1532
1533 set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
1534 lockend, EXTENT_NORESERVE, NULL,
1535 NULL, GFP_NOFS);
1536 only_release_metadata = false;
1537 }
1538
1539 cond_resched();
1540
1541 balance_dirty_pages_ratelimited(inode->i_mapping);
1542 if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1543 btrfs_btree_balance_dirty(root);
1544
1545 pos += copied;
1546 num_written += copied;
1547 }
1548
1549 kfree(pages);
1550
1551 if (release_bytes) {
1552 if (only_release_metadata)
1553 btrfs_delalloc_release_metadata(inode, release_bytes);
1554 else
1555 btrfs_delalloc_release_space(inode, release_bytes);
1556 }
1557
1558 return num_written ? num_written : ret;
1559 }
1560
1561 static ssize_t __btrfs_direct_write(struct kiocb *iocb,
1562 const struct iovec *iov,
1563 unsigned long nr_segs, loff_t pos,
1564 loff_t *ppos, size_t count, size_t ocount)
1565 {
1566 struct file *file = iocb->ki_filp;
1567 struct iov_iter i;
1568 ssize_t written;
1569 ssize_t written_buffered;
1570 loff_t endbyte;
1571 int err;
1572
1573 written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
1574 count, ocount);
1575
1576 if (written < 0 || written == count)
1577 return written;
1578
1579 pos += written;
1580 count -= written;
1581 iov_iter_init(&i, iov, nr_segs, count, written);
1582 written_buffered = __btrfs_buffered_write(file, &i, pos);
1583 if (written_buffered < 0) {
1584 err = written_buffered;
1585 goto out;
1586 }
1587 endbyte = pos + written_buffered - 1;
1588 err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
1589 if (err)
1590 goto out;
1591 written += written_buffered;
1592 *ppos = pos + written_buffered;
1593 invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
1594 endbyte >> PAGE_CACHE_SHIFT);
1595 out:
1596 return written ? written : err;
1597 }
1598
1599 static void update_time_for_write(struct inode *inode)
1600 {
1601 struct timespec now;
1602
1603 if (IS_NOCMTIME(inode))
1604 return;
1605
1606 now = current_fs_time(inode->i_sb);
1607 if (!timespec_equal(&inode->i_mtime, &now))
1608 inode->i_mtime = now;
1609
1610 if (!timespec_equal(&inode->i_ctime, &now))
1611 inode->i_ctime = now;
1612
1613 if (IS_I_VERSION(inode))
1614 inode_inc_iversion(inode);
1615 }
1616
1617 static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
1618 const struct iovec *iov,
1619 unsigned long nr_segs, loff_t pos)
1620 {
1621 struct file *file = iocb->ki_filp;
1622 struct inode *inode = file_inode(file);
1623 struct btrfs_root *root = BTRFS_I(inode)->root;
1624 loff_t *ppos = &iocb->ki_pos;
1625 u64 start_pos;
1626 ssize_t num_written = 0;
1627 ssize_t err = 0;
1628 size_t count, ocount;
1629 bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
1630
1631 mutex_lock(&inode->i_mutex);
1632
1633 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1634 if (err) {
1635 mutex_unlock(&inode->i_mutex);
1636 goto out;
1637 }
1638 count = ocount;
1639
1640 current->backing_dev_info = inode->i_mapping->backing_dev_info;
1641 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1642 if (err) {
1643 mutex_unlock(&inode->i_mutex);
1644 goto out;
1645 }
1646
1647 if (count == 0) {
1648 mutex_unlock(&inode->i_mutex);
1649 goto out;
1650 }
1651
1652 err = file_remove_suid(file);
1653 if (err) {
1654 mutex_unlock(&inode->i_mutex);
1655 goto out;
1656 }
1657
1658 /*
1659 * If BTRFS flips readonly due to some impossible error
1660 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1661 * although we have opened a file as writable, we have
1662 * to stop this write operation to ensure FS consistency.
1663 */
1664 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1665 mutex_unlock(&inode->i_mutex);
1666 err = -EROFS;
1667 goto out;
1668 }
1669
1670 /*
1671 * We reserve space for updating the inode when we reserve space for the
1672 * extent we are going to write, so we will enospc out there. We don't
1673 * need to start yet another transaction to update the inode as we will
1674 * update the inode when we finish writing whatever data we write.
1675 */
1676 update_time_for_write(inode);
1677
1678 start_pos = round_down(pos, root->sectorsize);
1679 if (start_pos > i_size_read(inode)) {
1680 err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
1681 if (err) {
1682 mutex_unlock(&inode->i_mutex);
1683 goto out;
1684 }
1685 }
1686
1687 if (sync)
1688 atomic_inc(&BTRFS_I(inode)->sync_writers);
1689
1690 if (unlikely(file->f_flags & O_DIRECT)) {
1691 num_written = __btrfs_direct_write(iocb, iov, nr_segs,
1692 pos, ppos, count, ocount);
1693 } else {
1694 struct iov_iter i;
1695
1696 iov_iter_init(&i, iov, nr_segs, count, num_written);
1697
1698 num_written = __btrfs_buffered_write(file, &i, pos);
1699 if (num_written > 0)
1700 *ppos = pos + num_written;
1701 }
1702
1703 mutex_unlock(&inode->i_mutex);
1704
1705 /*
1706 * we want to make sure fsync finds this change
1707 * but we haven't joined a transaction running right now.
1708 *
1709 * Later on, someone is sure to update the inode and get the
1710 * real transid recorded.
1711 *
1712 * We set last_trans now to the fs_info generation + 1,
1713 * this will either be one more than the running transaction
1714 * or the generation used for the next transaction if there isn't
1715 * one running right now.
1716 *
1717 * We also have to set last_sub_trans to the current log transid,
1718 * otherwise subsequent syncs to a file that's been synced in this
1719 * transaction will appear to have already occured.
1720 */
1721 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1722 BTRFS_I(inode)->last_sub_trans = root->log_transid;
1723 if (num_written > 0) {
1724 err = generic_write_sync(file, pos, num_written);
1725 if (err < 0 && num_written > 0)
1726 num_written = err;
1727 }
1728
1729 if (sync)
1730 atomic_dec(&BTRFS_I(inode)->sync_writers);
1731 out:
1732 current->backing_dev_info = NULL;
1733 return num_written ? num_written : err;
1734 }
1735
1736 int btrfs_release_file(struct inode *inode, struct file *filp)
1737 {
1738 /*
1739 * ordered_data_close is set by settattr when we are about to truncate
1740 * a file from a non-zero size to a zero size. This tries to
1741 * flush down new bytes that may have been written if the
1742 * application were using truncate to replace a file in place.
1743 */
1744 if (test_and_clear_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
1745 &BTRFS_I(inode)->runtime_flags)) {
1746 struct btrfs_trans_handle *trans;
1747 struct btrfs_root *root = BTRFS_I(inode)->root;
1748
1749 /*
1750 * We need to block on a committing transaction to keep us from
1751 * throwing a ordered operation on to the list and causing
1752 * something like sync to deadlock trying to flush out this
1753 * inode.
1754 */
1755 trans = btrfs_start_transaction(root, 0);
1756 if (IS_ERR(trans))
1757 return PTR_ERR(trans);
1758 btrfs_add_ordered_operation(trans, BTRFS_I(inode)->root, inode);
1759 btrfs_end_transaction(trans, root);
1760 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1761 filemap_flush(inode->i_mapping);
1762 }
1763 if (filp->private_data)
1764 btrfs_ioctl_trans_end(filp);
1765 return 0;
1766 }
1767
1768 /*
1769 * fsync call for both files and directories. This logs the inode into
1770 * the tree log instead of forcing full commits whenever possible.
1771 *
1772 * It needs to call filemap_fdatawait so that all ordered extent updates are
1773 * in the metadata btree are up to date for copying to the log.
1774 *
1775 * It drops the inode mutex before doing the tree log commit. This is an
1776 * important optimization for directories because holding the mutex prevents
1777 * new operations on the dir while we write to disk.
1778 */
1779 int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
1780 {
1781 struct dentry *dentry = file->f_path.dentry;
1782 struct inode *inode = dentry->d_inode;
1783 struct btrfs_root *root = BTRFS_I(inode)->root;
1784 int ret = 0;
1785 struct btrfs_trans_handle *trans;
1786 bool full_sync = 0;
1787
1788 trace_btrfs_sync_file(file, datasync);
1789
1790 /*
1791 * We write the dirty pages in the range and wait until they complete
1792 * out of the ->i_mutex. If so, we can flush the dirty pages by
1793 * multi-task, and make the performance up. See
1794 * btrfs_wait_ordered_range for an explanation of the ASYNC check.
1795 */
1796 atomic_inc(&BTRFS_I(inode)->sync_writers);
1797 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
1798 if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1799 &BTRFS_I(inode)->runtime_flags))
1800 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
1801 atomic_dec(&BTRFS_I(inode)->sync_writers);
1802 if (ret)
1803 return ret;
1804
1805 mutex_lock(&inode->i_mutex);
1806
1807 /*
1808 * We flush the dirty pages again to avoid some dirty pages in the
1809 * range being left.
1810 */
1811 atomic_inc(&root->log_batch);
1812 full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1813 &BTRFS_I(inode)->runtime_flags);
1814 if (full_sync) {
1815 ret = btrfs_wait_ordered_range(inode, start, end - start + 1);
1816 if (ret) {
1817 mutex_unlock(&inode->i_mutex);
1818 goto out;
1819 }
1820 }
1821 atomic_inc(&root->log_batch);
1822
1823 /*
1824 * check the transaction that last modified this inode
1825 * and see if its already been committed
1826 */
1827 if (!BTRFS_I(inode)->last_trans) {
1828 mutex_unlock(&inode->i_mutex);
1829 goto out;
1830 }
1831
1832 /*
1833 * if the last transaction that changed this file was before
1834 * the current transaction, we can bail out now without any
1835 * syncing
1836 */
1837 smp_mb();
1838 if (btrfs_inode_in_log(inode, root->fs_info->generation) ||
1839 BTRFS_I(inode)->last_trans <=
1840 root->fs_info->last_trans_committed) {
1841 BTRFS_I(inode)->last_trans = 0;
1842
1843 /*
1844 * We'v had everything committed since the last time we were
1845 * modified so clear this flag in case it was set for whatever
1846 * reason, it's no longer relevant.
1847 */
1848 clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1849 &BTRFS_I(inode)->runtime_flags);
1850 mutex_unlock(&inode->i_mutex);
1851 goto out;
1852 }
1853
1854 /*
1855 * ok we haven't committed the transaction yet, lets do a commit
1856 */
1857 if (file->private_data)
1858 btrfs_ioctl_trans_end(file);
1859
1860 trans = btrfs_start_transaction(root, 0);
1861 if (IS_ERR(trans)) {
1862 ret = PTR_ERR(trans);
1863 mutex_unlock(&inode->i_mutex);
1864 goto out;
1865 }
1866
1867 ret = btrfs_log_dentry_safe(trans, root, dentry);
1868 if (ret < 0) {
1869 /* Fallthrough and commit/free transaction. */
1870 ret = 1;
1871 }
1872
1873 /* we've logged all the items and now have a consistent
1874 * version of the file in the log. It is possible that
1875 * someone will come in and modify the file, but that's
1876 * fine because the log is consistent on disk, and we
1877 * have references to all of the file's extents
1878 *
1879 * It is possible that someone will come in and log the
1880 * file again, but that will end up using the synchronization
1881 * inside btrfs_sync_log to keep things safe.
1882 */
1883 mutex_unlock(&inode->i_mutex);
1884
1885 if (ret != BTRFS_NO_LOG_SYNC) {
1886 if (!ret) {
1887 ret = btrfs_sync_log(trans, root);
1888 if (!ret) {
1889 ret = btrfs_end_transaction(trans, root);
1890 goto out;
1891 }
1892 }
1893 if (!full_sync) {
1894 ret = btrfs_wait_ordered_range(inode, start,
1895 end - start + 1);
1896 if (ret)
1897 goto out;
1898 }
1899 ret = btrfs_commit_transaction(trans, root);
1900 } else {
1901 ret = btrfs_end_transaction(trans, root);
1902 }
1903 out:
1904 return ret > 0 ? -EIO : ret;
1905 }
1906
1907 static const struct vm_operations_struct btrfs_file_vm_ops = {
1908 .fault = filemap_fault,
1909 .page_mkwrite = btrfs_page_mkwrite,
1910 .remap_pages = generic_file_remap_pages,
1911 };
1912
1913 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1914 {
1915 struct address_space *mapping = filp->f_mapping;
1916
1917 if (!mapping->a_ops->readpage)
1918 return -ENOEXEC;
1919
1920 file_accessed(filp);
1921 vma->vm_ops = &btrfs_file_vm_ops;
1922
1923 return 0;
1924 }
1925
1926 static int hole_mergeable(struct inode *inode, struct extent_buffer *leaf,
1927 int slot, u64 start, u64 end)
1928 {
1929 struct btrfs_file_extent_item *fi;
1930 struct btrfs_key key;
1931
1932 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
1933 return 0;
1934
1935 btrfs_item_key_to_cpu(leaf, &key, slot);
1936 if (key.objectid != btrfs_ino(inode) ||
1937 key.type != BTRFS_EXTENT_DATA_KEY)
1938 return 0;
1939
1940 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
1941
1942 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
1943 return 0;
1944
1945 if (btrfs_file_extent_disk_bytenr(leaf, fi))
1946 return 0;
1947
1948 if (key.offset == end)
1949 return 1;
1950 if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start)
1951 return 1;
1952 return 0;
1953 }
1954
1955 static int fill_holes(struct btrfs_trans_handle *trans, struct inode *inode,
1956 struct btrfs_path *path, u64 offset, u64 end)
1957 {
1958 struct btrfs_root *root = BTRFS_I(inode)->root;
1959 struct extent_buffer *leaf;
1960 struct btrfs_file_extent_item *fi;
1961 struct extent_map *hole_em;
1962 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1963 struct btrfs_key key;
1964 int ret;
1965
1966 key.objectid = btrfs_ino(inode);
1967 key.type = BTRFS_EXTENT_DATA_KEY;
1968 key.offset = offset;
1969
1970
1971 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1972 if (ret < 0)
1973 return ret;
1974 BUG_ON(!ret);
1975
1976 leaf = path->nodes[0];
1977 if (hole_mergeable(inode, leaf, path->slots[0]-1, offset, end)) {
1978 u64 num_bytes;
1979
1980 path->slots[0]--;
1981 fi = btrfs_item_ptr(leaf, path->slots[0],
1982 struct btrfs_file_extent_item);
1983 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) +
1984 end - offset;
1985 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1986 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
1987 btrfs_set_file_extent_offset(leaf, fi, 0);
1988 btrfs_mark_buffer_dirty(leaf);
1989 goto out;
1990 }
1991
1992 if (hole_mergeable(inode, leaf, path->slots[0]+1, offset, end)) {
1993 u64 num_bytes;
1994
1995 path->slots[0]++;
1996 key.offset = offset;
1997 btrfs_set_item_key_safe(root, path, &key);
1998 fi = btrfs_item_ptr(leaf, path->slots[0],
1999 struct btrfs_file_extent_item);
2000 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
2001 offset;
2002 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2003 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2004 btrfs_set_file_extent_offset(leaf, fi, 0);
2005 btrfs_mark_buffer_dirty(leaf);
2006 goto out;
2007 }
2008 btrfs_release_path(path);
2009
2010 ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
2011 0, 0, end - offset, 0, end - offset,
2012 0, 0, 0);
2013 if (ret)
2014 return ret;
2015
2016 out:
2017 btrfs_release_path(path);
2018
2019 hole_em = alloc_extent_map();
2020 if (!hole_em) {
2021 btrfs_drop_extent_cache(inode, offset, end - 1, 0);
2022 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2023 &BTRFS_I(inode)->runtime_flags);
2024 } else {
2025 hole_em->start = offset;
2026 hole_em->len = end - offset;
2027 hole_em->ram_bytes = hole_em->len;
2028 hole_em->orig_start = offset;
2029
2030 hole_em->block_start = EXTENT_MAP_HOLE;
2031 hole_em->block_len = 0;
2032 hole_em->orig_block_len = 0;
2033 hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
2034 hole_em->compress_type = BTRFS_COMPRESS_NONE;
2035 hole_em->generation = trans->transid;
2036
2037 do {
2038 btrfs_drop_extent_cache(inode, offset, end - 1, 0);
2039 write_lock(&em_tree->lock);
2040 ret = add_extent_mapping(em_tree, hole_em, 1);
2041 write_unlock(&em_tree->lock);
2042 } while (ret == -EEXIST);
2043 free_extent_map(hole_em);
2044 if (ret)
2045 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2046 &BTRFS_I(inode)->runtime_flags);
2047 }
2048
2049 return 0;
2050 }
2051
2052 static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
2053 {
2054 struct btrfs_root *root = BTRFS_I(inode)->root;
2055 struct extent_state *cached_state = NULL;
2056 struct btrfs_path *path;
2057 struct btrfs_block_rsv *rsv;
2058 struct btrfs_trans_handle *trans;
2059 u64 lockstart = round_up(offset, BTRFS_I(inode)->root->sectorsize);
2060 u64 lockend = round_down(offset + len,
2061 BTRFS_I(inode)->root->sectorsize) - 1;
2062 u64 cur_offset = lockstart;
2063 u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
2064 u64 drop_end;
2065 int ret = 0;
2066 int err = 0;
2067 bool same_page = ((offset >> PAGE_CACHE_SHIFT) ==
2068 ((offset + len - 1) >> PAGE_CACHE_SHIFT));
2069
2070 ret = btrfs_wait_ordered_range(inode, offset, len);
2071 if (ret)
2072 return ret;
2073
2074 mutex_lock(&inode->i_mutex);
2075 /*
2076 * We needn't truncate any page which is beyond the end of the file
2077 * because we are sure there is no data there.
2078 */
2079 /*
2080 * Only do this if we are in the same page and we aren't doing the
2081 * entire page.
2082 */
2083 if (same_page && len < PAGE_CACHE_SIZE) {
2084 if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE))
2085 ret = btrfs_truncate_page(inode, offset, len, 0);
2086 mutex_unlock(&inode->i_mutex);
2087 return ret;
2088 }
2089
2090 /* zero back part of the first page */
2091 if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE)) {
2092 ret = btrfs_truncate_page(inode, offset, 0, 0);
2093 if (ret) {
2094 mutex_unlock(&inode->i_mutex);
2095 return ret;
2096 }
2097 }
2098
2099 /* zero the front end of the last page */
2100 if (offset + len < round_up(inode->i_size, PAGE_CACHE_SIZE)) {
2101 ret = btrfs_truncate_page(inode, offset + len, 0, 1);
2102 if (ret) {
2103 mutex_unlock(&inode->i_mutex);
2104 return ret;
2105 }
2106 }
2107
2108 if (lockend < lockstart) {
2109 mutex_unlock(&inode->i_mutex);
2110 return 0;
2111 }
2112
2113 while (1) {
2114 struct btrfs_ordered_extent *ordered;
2115
2116 truncate_pagecache_range(inode, lockstart, lockend);
2117
2118 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2119 0, &cached_state);
2120 ordered = btrfs_lookup_first_ordered_extent(inode, lockend);
2121
2122 /*
2123 * We need to make sure we have no ordered extents in this range
2124 * and nobody raced in and read a page in this range, if we did
2125 * we need to try again.
2126 */
2127 if ((!ordered ||
2128 (ordered->file_offset + ordered->len < lockstart ||
2129 ordered->file_offset > lockend)) &&
2130 !test_range_bit(&BTRFS_I(inode)->io_tree, lockstart,
2131 lockend, EXTENT_UPTODATE, 0,
2132 cached_state)) {
2133 if (ordered)
2134 btrfs_put_ordered_extent(ordered);
2135 break;
2136 }
2137 if (ordered)
2138 btrfs_put_ordered_extent(ordered);
2139 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
2140 lockend, &cached_state, GFP_NOFS);
2141 ret = btrfs_wait_ordered_range(inode, lockstart,
2142 lockend - lockstart + 1);
2143 if (ret) {
2144 mutex_unlock(&inode->i_mutex);
2145 return ret;
2146 }
2147 }
2148
2149 path = btrfs_alloc_path();
2150 if (!path) {
2151 ret = -ENOMEM;
2152 goto out;
2153 }
2154
2155 rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
2156 if (!rsv) {
2157 ret = -ENOMEM;
2158 goto out_free;
2159 }
2160 rsv->size = btrfs_calc_trunc_metadata_size(root, 1);
2161 rsv->failfast = 1;
2162
2163 /*
2164 * 1 - update the inode
2165 * 1 - removing the extents in the range
2166 * 1 - adding the hole extent
2167 */
2168 trans = btrfs_start_transaction(root, 3);
2169 if (IS_ERR(trans)) {
2170 err = PTR_ERR(trans);
2171 goto out_free;
2172 }
2173
2174 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
2175 min_size);
2176 BUG_ON(ret);
2177 trans->block_rsv = rsv;
2178
2179 while (cur_offset < lockend) {
2180 ret = __btrfs_drop_extents(trans, root, inode, path,
2181 cur_offset, lockend + 1,
2182 &drop_end, 1);
2183 if (ret != -ENOSPC)
2184 break;
2185
2186 trans->block_rsv = &root->fs_info->trans_block_rsv;
2187
2188 ret = fill_holes(trans, inode, path, cur_offset, drop_end);
2189 if (ret) {
2190 err = ret;
2191 break;
2192 }
2193
2194 cur_offset = drop_end;
2195
2196 ret = btrfs_update_inode(trans, root, inode);
2197 if (ret) {
2198 err = ret;
2199 break;
2200 }
2201
2202 btrfs_end_transaction(trans, root);
2203 btrfs_btree_balance_dirty(root);
2204
2205 trans = btrfs_start_transaction(root, 3);
2206 if (IS_ERR(trans)) {
2207 ret = PTR_ERR(trans);
2208 trans = NULL;
2209 break;
2210 }
2211
2212 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
2213 rsv, min_size);
2214 BUG_ON(ret); /* shouldn't happen */
2215 trans->block_rsv = rsv;
2216 }
2217
2218 if (ret) {
2219 err = ret;
2220 goto out_trans;
2221 }
2222
2223 trans->block_rsv = &root->fs_info->trans_block_rsv;
2224 ret = fill_holes(trans, inode, path, cur_offset, drop_end);
2225 if (ret) {
2226 err = ret;
2227 goto out_trans;
2228 }
2229
2230 out_trans:
2231 if (!trans)
2232 goto out_free;
2233
2234 inode_inc_iversion(inode);
2235 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
2236
2237 trans->block_rsv = &root->fs_info->trans_block_rsv;
2238 ret = btrfs_update_inode(trans, root, inode);
2239 btrfs_end_transaction(trans, root);
2240 btrfs_btree_balance_dirty(root);
2241 out_free:
2242 btrfs_free_path(path);
2243 btrfs_free_block_rsv(root, rsv);
2244 out:
2245 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2246 &cached_state, GFP_NOFS);
2247 mutex_unlock(&inode->i_mutex);
2248 if (ret && !err)
2249 err = ret;
2250 return err;
2251 }
2252
2253 static long btrfs_fallocate(struct file *file, int mode,
2254 loff_t offset, loff_t len)
2255 {
2256 struct inode *inode = file_inode(file);
2257 struct extent_state *cached_state = NULL;
2258 struct btrfs_root *root = BTRFS_I(inode)->root;
2259 u64 cur_offset;
2260 u64 last_byte;
2261 u64 alloc_start;
2262 u64 alloc_end;
2263 u64 alloc_hint = 0;
2264 u64 locked_end;
2265 struct extent_map *em;
2266 int blocksize = BTRFS_I(inode)->root->sectorsize;
2267 int ret;
2268
2269 alloc_start = round_down(offset, blocksize);
2270 alloc_end = round_up(offset + len, blocksize);
2271
2272 /* Make sure we aren't being give some crap mode */
2273 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
2274 return -EOPNOTSUPP;
2275
2276 if (mode & FALLOC_FL_PUNCH_HOLE)
2277 return btrfs_punch_hole(inode, offset, len);
2278
2279 /*
2280 * Make sure we have enough space before we do the
2281 * allocation.
2282 */
2283 ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
2284 if (ret)
2285 return ret;
2286 if (root->fs_info->quota_enabled) {
2287 ret = btrfs_qgroup_reserve(root, alloc_end - alloc_start);
2288 if (ret)
2289 goto out_reserve_fail;
2290 }
2291
2292 mutex_lock(&inode->i_mutex);
2293 ret = inode_newsize_ok(inode, alloc_end);
2294 if (ret)
2295 goto out;
2296
2297 if (alloc_start > inode->i_size) {
2298 ret = btrfs_cont_expand(inode, i_size_read(inode),
2299 alloc_start);
2300 if (ret)
2301 goto out;
2302 } else {
2303 /*
2304 * If we are fallocating from the end of the file onward we
2305 * need to zero out the end of the page if i_size lands in the
2306 * middle of a page.
2307 */
2308 ret = btrfs_truncate_page(inode, inode->i_size, 0, 0);
2309 if (ret)
2310 goto out;
2311 }
2312
2313 /*
2314 * wait for ordered IO before we have any locks. We'll loop again
2315 * below with the locks held.
2316 */
2317 ret = btrfs_wait_ordered_range(inode, alloc_start,
2318 alloc_end - alloc_start);
2319 if (ret)
2320 goto out;
2321
2322 locked_end = alloc_end - 1;
2323 while (1) {
2324 struct btrfs_ordered_extent *ordered;
2325
2326 /* the extent lock is ordered inside the running
2327 * transaction
2328 */
2329 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
2330 locked_end, 0, &cached_state);
2331 ordered = btrfs_lookup_first_ordered_extent(inode,
2332 alloc_end - 1);
2333 if (ordered &&
2334 ordered->file_offset + ordered->len > alloc_start &&
2335 ordered->file_offset < alloc_end) {
2336 btrfs_put_ordered_extent(ordered);
2337 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
2338 alloc_start, locked_end,
2339 &cached_state, GFP_NOFS);
2340 /*
2341 * we can't wait on the range with the transaction
2342 * running or with the extent lock held
2343 */
2344 ret = btrfs_wait_ordered_range(inode, alloc_start,
2345 alloc_end - alloc_start);
2346 if (ret)
2347 goto out;
2348 } else {
2349 if (ordered)
2350 btrfs_put_ordered_extent(ordered);
2351 break;
2352 }
2353 }
2354
2355 cur_offset = alloc_start;
2356 while (1) {
2357 u64 actual_end;
2358
2359 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
2360 alloc_end - cur_offset, 0);
2361 if (IS_ERR_OR_NULL(em)) {
2362 if (!em)
2363 ret = -ENOMEM;
2364 else
2365 ret = PTR_ERR(em);
2366 break;
2367 }
2368 last_byte = min(extent_map_end(em), alloc_end);
2369 actual_end = min_t(u64, extent_map_end(em), offset + len);
2370 last_byte = ALIGN(last_byte, blocksize);
2371
2372 if (em->block_start == EXTENT_MAP_HOLE ||
2373 (cur_offset >= inode->i_size &&
2374 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
2375 ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
2376 last_byte - cur_offset,
2377 1 << inode->i_blkbits,
2378 offset + len,
2379 &alloc_hint);
2380
2381 if (ret < 0) {
2382 free_extent_map(em);
2383 break;
2384 }
2385 } else if (actual_end > inode->i_size &&
2386 !(mode & FALLOC_FL_KEEP_SIZE)) {
2387 /*
2388 * We didn't need to allocate any more space, but we
2389 * still extended the size of the file so we need to
2390 * update i_size.
2391 */
2392 inode->i_ctime = CURRENT_TIME;
2393 i_size_write(inode, actual_end);
2394 btrfs_ordered_update_i_size(inode, actual_end, NULL);
2395 }
2396 free_extent_map(em);
2397
2398 cur_offset = last_byte;
2399 if (cur_offset >= alloc_end) {
2400 ret = 0;
2401 break;
2402 }
2403 }
2404 unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
2405 &cached_state, GFP_NOFS);
2406 out:
2407 mutex_unlock(&inode->i_mutex);
2408 if (root->fs_info->quota_enabled)
2409 btrfs_qgroup_free(root, alloc_end - alloc_start);
2410 out_reserve_fail:
2411 /* Let go of our reservation. */
2412 btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
2413 return ret;
2414 }
2415
2416 static int find_desired_extent(struct inode *inode, loff_t *offset, int whence)
2417 {
2418 struct btrfs_root *root = BTRFS_I(inode)->root;
2419 struct extent_map *em = NULL;
2420 struct extent_state *cached_state = NULL;
2421 u64 lockstart = *offset;
2422 u64 lockend = i_size_read(inode);
2423 u64 start = *offset;
2424 u64 len = i_size_read(inode);
2425 int ret = 0;
2426
2427 lockend = max_t(u64, root->sectorsize, lockend);
2428 if (lockend <= lockstart)
2429 lockend = lockstart + root->sectorsize;
2430
2431 lockend--;
2432 len = lockend - lockstart + 1;
2433
2434 len = max_t(u64, len, root->sectorsize);
2435 if (inode->i_size == 0)
2436 return -ENXIO;
2437
2438 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0,
2439 &cached_state);
2440
2441 while (start < inode->i_size) {
2442 em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
2443 if (IS_ERR(em)) {
2444 ret = PTR_ERR(em);
2445 em = NULL;
2446 break;
2447 }
2448
2449 if (whence == SEEK_HOLE &&
2450 (em->block_start == EXTENT_MAP_HOLE ||
2451 test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
2452 break;
2453 else if (whence == SEEK_DATA &&
2454 (em->block_start != EXTENT_MAP_HOLE &&
2455 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
2456 break;
2457
2458 start = em->start + em->len;
2459 free_extent_map(em);
2460 em = NULL;
2461 cond_resched();
2462 }
2463 free_extent_map(em);
2464 if (!ret) {
2465 if (whence == SEEK_DATA && start >= inode->i_size)
2466 ret = -ENXIO;
2467 else
2468 *offset = min_t(loff_t, start, inode->i_size);
2469 }
2470 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2471 &cached_state, GFP_NOFS);
2472 return ret;
2473 }
2474
2475 static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
2476 {
2477 struct inode *inode = file->f_mapping->host;
2478 int ret;
2479
2480 mutex_lock(&inode->i_mutex);
2481 switch (whence) {
2482 case SEEK_END:
2483 case SEEK_CUR:
2484 offset = generic_file_llseek(file, offset, whence);
2485 goto out;
2486 case SEEK_DATA:
2487 case SEEK_HOLE:
2488 if (offset >= i_size_read(inode)) {
2489 mutex_unlock(&inode->i_mutex);
2490 return -ENXIO;
2491 }
2492
2493 ret = find_desired_extent(inode, &offset, whence);
2494 if (ret) {
2495 mutex_unlock(&inode->i_mutex);
2496 return ret;
2497 }
2498 }
2499
2500 offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
2501 out:
2502 mutex_unlock(&inode->i_mutex);
2503 return offset;
2504 }
2505
2506 const struct file_operations btrfs_file_operations = {
2507 .llseek = btrfs_file_llseek,
2508 .read = do_sync_read,
2509 .write = do_sync_write,
2510 .aio_read = generic_file_aio_read,
2511 .splice_read = generic_file_splice_read,
2512 .aio_write = btrfs_file_aio_write,
2513 .mmap = btrfs_file_mmap,
2514 .open = generic_file_open,
2515 .release = btrfs_release_file,
2516 .fsync = btrfs_sync_file,
2517 .fallocate = btrfs_fallocate,
2518 .unlocked_ioctl = btrfs_ioctl,
2519 #ifdef CONFIG_COMPAT
2520 .compat_ioctl = btrfs_ioctl,
2521 #endif
2522 };
2523
2524 void btrfs_auto_defrag_exit(void)
2525 {
2526 if (btrfs_inode_defrag_cachep)
2527 kmem_cache_destroy(btrfs_inode_defrag_cachep);
2528 }
2529
2530 int btrfs_auto_defrag_init(void)
2531 {
2532 btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
2533 sizeof(struct inode_defrag), 0,
2534 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
2535 NULL);
2536 if (!btrfs_inode_defrag_cachep)
2537 return -ENOMEM;
2538
2539 return 0;
2540 }
Linus' kernel tree