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Merge remote-tracking branch 'asoc/topic/mxs' into asoc-next
[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/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 "compat.h"
43 #include "volumes.h"
44
45 static struct kmem_cache *btrfs_inode_defrag_cachep;
46 /*
47 * when auto defrag is enabled we
48 * queue up these defrag structs to remember which
49 * inodes need defragging passes
50 */
51 struct inode_defrag {
52 struct rb_node rb_node;
53 /* objectid */
54 u64 ino;
55 /*
56 * transid where the defrag was added, we search for
57 * extents newer than this
58 */
59 u64 transid;
60
61 /* root objectid */
62 u64 root;
63
64 /* last offset we were able to defrag */
65 u64 last_offset;
66
67 /* if we've wrapped around back to zero once already */
68 int cycled;
69 };
70
71 static int __compare_inode_defrag(struct inode_defrag *defrag1,
72 struct inode_defrag *defrag2)
73 {
74 if (defrag1->root > defrag2->root)
75 return 1;
76 else if (defrag1->root < defrag2->root)
77 return -1;
78 else if (defrag1->ino > defrag2->ino)
79 return 1;
80 else if (defrag1->ino < defrag2->ino)
81 return -1;
82 else
83 return 0;
84 }
85
86 /* pop a record for an inode into the defrag tree. The lock
87 * must be held already
88 *
89 * If you're inserting a record for an older transid than an
90 * existing record, the transid already in the tree is lowered
91 *
92 * If an existing record is found the defrag item you
93 * pass in is freed
94 */
95 static int __btrfs_add_inode_defrag(struct inode *inode,
96 struct inode_defrag *defrag)
97 {
98 struct btrfs_root *root = BTRFS_I(inode)->root;
99 struct inode_defrag *entry;
100 struct rb_node **p;
101 struct rb_node *parent = NULL;
102 int ret;
103
104 p = &root->fs_info->defrag_inodes.rb_node;
105 while (*p) {
106 parent = *p;
107 entry = rb_entry(parent, struct inode_defrag, rb_node);
108
109 ret = __compare_inode_defrag(defrag, entry);
110 if (ret < 0)
111 p = &parent->rb_left;
112 else if (ret > 0)
113 p = &parent->rb_right;
114 else {
115 /* if we're reinserting an entry for
116 * an old defrag run, make sure to
117 * lower the transid of our existing record
118 */
119 if (defrag->transid < entry->transid)
120 entry->transid = defrag->transid;
121 if (defrag->last_offset > entry->last_offset)
122 entry->last_offset = defrag->last_offset;
123 return -EEXIST;
124 }
125 }
126 set_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
127 rb_link_node(&defrag->rb_node, parent, p);
128 rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes);
129 return 0;
130 }
131
132 static inline int __need_auto_defrag(struct btrfs_root *root)
133 {
134 if (!btrfs_test_opt(root, AUTO_DEFRAG))
135 return 0;
136
137 if (btrfs_fs_closing(root->fs_info))
138 return 0;
139
140 return 1;
141 }
142
143 /*
144 * insert a defrag record for this inode if auto defrag is
145 * enabled
146 */
147 int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
148 struct inode *inode)
149 {
150 struct btrfs_root *root = BTRFS_I(inode)->root;
151 struct inode_defrag *defrag;
152 u64 transid;
153 int ret;
154
155 if (!__need_auto_defrag(root))
156 return 0;
157
158 if (test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags))
159 return 0;
160
161 if (trans)
162 transid = trans->transid;
163 else
164 transid = BTRFS_I(inode)->root->last_trans;
165
166 defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS);
167 if (!defrag)
168 return -ENOMEM;
169
170 defrag->ino = btrfs_ino(inode);
171 defrag->transid = transid;
172 defrag->root = root->root_key.objectid;
173
174 spin_lock(&root->fs_info->defrag_inodes_lock);
175 if (!test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags)) {
176 /*
177 * If we set IN_DEFRAG flag and evict the inode from memory,
178 * and then re-read this inode, this new inode doesn't have
179 * IN_DEFRAG flag. At the case, we may find the existed defrag.
180 */
181 ret = __btrfs_add_inode_defrag(inode, defrag);
182 if (ret)
183 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
184 } else {
185 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
186 }
187 spin_unlock(&root->fs_info->defrag_inodes_lock);
188 return 0;
189 }
190
191 /*
192 * Requeue the defrag object. If there is a defrag object that points to
193 * the same inode in the tree, we will merge them together (by
194 * __btrfs_add_inode_defrag()) and free the one that we want to requeue.
195 */
196 static void btrfs_requeue_inode_defrag(struct inode *inode,
197 struct inode_defrag *defrag)
198 {
199 struct btrfs_root *root = BTRFS_I(inode)->root;
200 int ret;
201
202 if (!__need_auto_defrag(root))
203 goto out;
204
205 /*
206 * Here we don't check the IN_DEFRAG flag, because we need merge
207 * them together.
208 */
209 spin_lock(&root->fs_info->defrag_inodes_lock);
210 ret = __btrfs_add_inode_defrag(inode, defrag);
211 spin_unlock(&root->fs_info->defrag_inodes_lock);
212 if (ret)
213 goto out;
214 return;
215 out:
216 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
217 }
218
219 /*
220 * pick the defragable inode that we want, if it doesn't exist, we will get
221 * the next one.
222 */
223 static struct inode_defrag *
224 btrfs_pick_defrag_inode(struct btrfs_fs_info *fs_info, u64 root, u64 ino)
225 {
226 struct inode_defrag *entry = NULL;
227 struct inode_defrag tmp;
228 struct rb_node *p;
229 struct rb_node *parent = NULL;
230 int ret;
231
232 tmp.ino = ino;
233 tmp.root = root;
234
235 spin_lock(&fs_info->defrag_inodes_lock);
236 p = fs_info->defrag_inodes.rb_node;
237 while (p) {
238 parent = p;
239 entry = rb_entry(parent, struct inode_defrag, rb_node);
240
241 ret = __compare_inode_defrag(&tmp, entry);
242 if (ret < 0)
243 p = parent->rb_left;
244 else if (ret > 0)
245 p = parent->rb_right;
246 else
247 goto out;
248 }
249
250 if (parent && __compare_inode_defrag(&tmp, entry) > 0) {
251 parent = rb_next(parent);
252 if (parent)
253 entry = rb_entry(parent, struct inode_defrag, rb_node);
254 else
255 entry = NULL;
256 }
257 out:
258 if (entry)
259 rb_erase(parent, &fs_info->defrag_inodes);
260 spin_unlock(&fs_info->defrag_inodes_lock);
261 return entry;
262 }
263
264 void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info)
265 {
266 struct inode_defrag *defrag;
267 struct rb_node *node;
268
269 spin_lock(&fs_info->defrag_inodes_lock);
270 node = rb_first(&fs_info->defrag_inodes);
271 while (node) {
272 rb_erase(node, &fs_info->defrag_inodes);
273 defrag = rb_entry(node, struct inode_defrag, rb_node);
274 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
275
276 if (need_resched()) {
277 spin_unlock(&fs_info->defrag_inodes_lock);
278 cond_resched();
279 spin_lock(&fs_info->defrag_inodes_lock);
280 }
281
282 node = rb_first(&fs_info->defrag_inodes);
283 }
284 spin_unlock(&fs_info->defrag_inodes_lock);
285 }
286
287 #define BTRFS_DEFRAG_BATCH 1024
288
289 static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
290 struct inode_defrag *defrag)
291 {
292 struct btrfs_root *inode_root;
293 struct inode *inode;
294 struct btrfs_key key;
295 struct btrfs_ioctl_defrag_range_args range;
296 int num_defrag;
297 int index;
298 int ret;
299
300 /* get the inode */
301 key.objectid = defrag->root;
302 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
303 key.offset = (u64)-1;
304
305 index = srcu_read_lock(&fs_info->subvol_srcu);
306
307 inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
308 if (IS_ERR(inode_root)) {
309 ret = PTR_ERR(inode_root);
310 goto cleanup;
311 }
312
313 key.objectid = defrag->ino;
314 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
315 key.offset = 0;
316 inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
317 if (IS_ERR(inode)) {
318 ret = PTR_ERR(inode);
319 goto cleanup;
320 }
321 srcu_read_unlock(&fs_info->subvol_srcu, index);
322
323 /* do a chunk of defrag */
324 clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
325 memset(&range, 0, sizeof(range));
326 range.len = (u64)-1;
327 range.start = defrag->last_offset;
328
329 sb_start_write(fs_info->sb);
330 num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
331 BTRFS_DEFRAG_BATCH);
332 sb_end_write(fs_info->sb);
333 /*
334 * if we filled the whole defrag batch, there
335 * must be more work to do. Queue this defrag
336 * again
337 */
338 if (num_defrag == BTRFS_DEFRAG_BATCH) {
339 defrag->last_offset = range.start;
340 btrfs_requeue_inode_defrag(inode, defrag);
341 } else if (defrag->last_offset && !defrag->cycled) {
342 /*
343 * we didn't fill our defrag batch, but
344 * we didn't start at zero. Make sure we loop
345 * around to the start of the file.
346 */
347 defrag->last_offset = 0;
348 defrag->cycled = 1;
349 btrfs_requeue_inode_defrag(inode, defrag);
350 } else {
351 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
352 }
353
354 iput(inode);
355 return 0;
356 cleanup:
357 srcu_read_unlock(&fs_info->subvol_srcu, index);
358 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
359 return ret;
360 }
361
362 /*
363 * run through the list of inodes in the FS that need
364 * defragging
365 */
366 int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
367 {
368 struct inode_defrag *defrag;
369 u64 first_ino = 0;
370 u64 root_objectid = 0;
371
372 atomic_inc(&fs_info->defrag_running);
373 while(1) {
374 /* Pause the auto defragger. */
375 if (test_bit(BTRFS_FS_STATE_REMOUNTING,
376 &fs_info->fs_state))
377 break;
378
379 if (!__need_auto_defrag(fs_info->tree_root))
380 break;
381
382 /* find an inode to defrag */
383 defrag = btrfs_pick_defrag_inode(fs_info, root_objectid,
384 first_ino);
385 if (!defrag) {
386 if (root_objectid || first_ino) {
387 root_objectid = 0;
388 first_ino = 0;
389 continue;
390 } else {
391 break;
392 }
393 }
394
395 first_ino = defrag->ino + 1;
396 root_objectid = defrag->root;
397
398 __btrfs_run_defrag_inode(fs_info, defrag);
399 }
400 atomic_dec(&fs_info->defrag_running);
401
402 /*
403 * during unmount, we use the transaction_wait queue to
404 * wait for the defragger to stop
405 */
406 wake_up(&fs_info->transaction_wait);
407 return 0;
408 }
409
410 /* simple helper to fault in pages and copy. This should go away
411 * and be replaced with calls into generic code.
412 */
413 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
414 size_t write_bytes,
415 struct page **prepared_pages,
416 struct iov_iter *i)
417 {
418 size_t copied = 0;
419 size_t total_copied = 0;
420 int pg = 0;
421 int offset = pos & (PAGE_CACHE_SIZE - 1);
422
423 while (write_bytes > 0) {
424 size_t count = min_t(size_t,
425 PAGE_CACHE_SIZE - offset, write_bytes);
426 struct page *page = prepared_pages[pg];
427 /*
428 * Copy data from userspace to the current page
429 *
430 * Disable pagefault to avoid recursive lock since
431 * the pages are already locked
432 */
433 pagefault_disable();
434 copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
435 pagefault_enable();
436
437 /* Flush processor's dcache for this page */
438 flush_dcache_page(page);
439
440 /*
441 * if we get a partial write, we can end up with
442 * partially up to date pages. These add
443 * a lot of complexity, so make sure they don't
444 * happen by forcing this copy to be retried.
445 *
446 * The rest of the btrfs_file_write code will fall
447 * back to page at a time copies after we return 0.
448 */
449 if (!PageUptodate(page) && copied < count)
450 copied = 0;
451
452 iov_iter_advance(i, copied);
453 write_bytes -= copied;
454 total_copied += copied;
455
456 /* Return to btrfs_file_aio_write to fault page */
457 if (unlikely(copied == 0))
458 break;
459
460 if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
461 offset += copied;
462 } else {
463 pg++;
464 offset = 0;
465 }
466 }
467 return total_copied;
468 }
469
470 /*
471 * unlocks pages after btrfs_file_write is done with them
472 */
473 static void btrfs_drop_pages(struct page **pages, size_t num_pages)
474 {
475 size_t i;
476 for (i = 0; i < num_pages; i++) {
477 /* page checked is some magic around finding pages that
478 * have been modified without going through btrfs_set_page_dirty
479 * clear it here
480 */
481 ClearPageChecked(pages[i]);
482 unlock_page(pages[i]);
483 mark_page_accessed(pages[i]);
484 page_cache_release(pages[i]);
485 }
486 }
487
488 /*
489 * after copy_from_user, pages need to be dirtied and we need to make
490 * sure holes are created between the current EOF and the start of
491 * any next extents (if required).
492 *
493 * this also makes the decision about creating an inline extent vs
494 * doing real data extents, marking pages dirty and delalloc as required.
495 */
496 int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
497 struct page **pages, size_t num_pages,
498 loff_t pos, size_t write_bytes,
499 struct extent_state **cached)
500 {
501 int err = 0;
502 int i;
503 u64 num_bytes;
504 u64 start_pos;
505 u64 end_of_last_block;
506 u64 end_pos = pos + write_bytes;
507 loff_t isize = i_size_read(inode);
508
509 start_pos = pos & ~((u64)root->sectorsize - 1);
510 num_bytes = ALIGN(write_bytes + pos - start_pos, root->sectorsize);
511
512 end_of_last_block = start_pos + num_bytes - 1;
513 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
514 cached);
515 if (err)
516 return err;
517
518 for (i = 0; i < num_pages; i++) {
519 struct page *p = pages[i];
520 SetPageUptodate(p);
521 ClearPageChecked(p);
522 set_page_dirty(p);
523 }
524
525 /*
526 * we've only changed i_size in ram, and we haven't updated
527 * the disk i_size. There is no need to log the inode
528 * at this time.
529 */
530 if (end_pos > isize)
531 i_size_write(inode, end_pos);
532 return 0;
533 }
534
535 /*
536 * this drops all the extents in the cache that intersect the range
537 * [start, end]. Existing extents are split as required.
538 */
539 void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
540 int skip_pinned)
541 {
542 struct extent_map *em;
543 struct extent_map *split = NULL;
544 struct extent_map *split2 = NULL;
545 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
546 u64 len = end - start + 1;
547 u64 gen;
548 int ret;
549 int testend = 1;
550 unsigned long flags;
551 int compressed = 0;
552 bool modified;
553
554 WARN_ON(end < start);
555 if (end == (u64)-1) {
556 len = (u64)-1;
557 testend = 0;
558 }
559 while (1) {
560 int no_splits = 0;
561
562 modified = false;
563 if (!split)
564 split = alloc_extent_map();
565 if (!split2)
566 split2 = alloc_extent_map();
567 if (!split || !split2)
568 no_splits = 1;
569
570 write_lock(&em_tree->lock);
571 em = lookup_extent_mapping(em_tree, start, len);
572 if (!em) {
573 write_unlock(&em_tree->lock);
574 break;
575 }
576 flags = em->flags;
577 gen = em->generation;
578 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
579 if (testend && em->start + em->len >= start + len) {
580 free_extent_map(em);
581 write_unlock(&em_tree->lock);
582 break;
583 }
584 start = em->start + em->len;
585 if (testend)
586 len = start + len - (em->start + em->len);
587 free_extent_map(em);
588 write_unlock(&em_tree->lock);
589 continue;
590 }
591 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
592 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
593 clear_bit(EXTENT_FLAG_LOGGING, &flags);
594 modified = !list_empty(&em->list);
595 remove_extent_mapping(em_tree, em);
596 if (no_splits)
597 goto next;
598
599 if (em->start < start) {
600 split->start = em->start;
601 split->len = start - em->start;
602
603 if (em->block_start < EXTENT_MAP_LAST_BYTE) {
604 split->orig_start = em->orig_start;
605 split->block_start = em->block_start;
606
607 if (compressed)
608 split->block_len = em->block_len;
609 else
610 split->block_len = split->len;
611 split->orig_block_len = max(split->block_len,
612 em->orig_block_len);
613 split->ram_bytes = em->ram_bytes;
614 } else {
615 split->orig_start = split->start;
616 split->block_len = 0;
617 split->block_start = em->block_start;
618 split->orig_block_len = 0;
619 split->ram_bytes = split->len;
620 }
621
622 split->generation = gen;
623 split->bdev = em->bdev;
624 split->flags = flags;
625 split->compress_type = em->compress_type;
626 ret = add_extent_mapping(em_tree, split, modified);
627 BUG_ON(ret); /* Logic error */
628 free_extent_map(split);
629 split = split2;
630 split2 = NULL;
631 }
632 if (testend && em->start + em->len > start + len) {
633 u64 diff = start + len - em->start;
634
635 split->start = start + len;
636 split->len = em->start + em->len - (start + len);
637 split->bdev = em->bdev;
638 split->flags = flags;
639 split->compress_type = em->compress_type;
640 split->generation = gen;
641
642 if (em->block_start < EXTENT_MAP_LAST_BYTE) {
643 split->orig_block_len = max(em->block_len,
644 em->orig_block_len);
645
646 split->ram_bytes = em->ram_bytes;
647 if (compressed) {
648 split->block_len = em->block_len;
649 split->block_start = em->block_start;
650 split->orig_start = em->orig_start;
651 } else {
652 split->block_len = split->len;
653 split->block_start = em->block_start
654 + diff;
655 split->orig_start = em->orig_start;
656 }
657 } else {
658 split->ram_bytes = split->len;
659 split->orig_start = split->start;
660 split->block_len = 0;
661 split->block_start = em->block_start;
662 split->orig_block_len = 0;
663 }
664
665 ret = add_extent_mapping(em_tree, split, modified);
666 BUG_ON(ret); /* Logic error */
667 free_extent_map(split);
668 split = NULL;
669 }
670 next:
671 write_unlock(&em_tree->lock);
672
673 /* once for us */
674 free_extent_map(em);
675 /* once for the tree*/
676 free_extent_map(em);
677 }
678 if (split)
679 free_extent_map(split);
680 if (split2)
681 free_extent_map(split2);
682 }
683
684 /*
685 * this is very complex, but the basic idea is to drop all extents
686 * in the range start - end. hint_block is filled in with a block number
687 * that would be a good hint to the block allocator for this file.
688 *
689 * If an extent intersects the range but is not entirely inside the range
690 * it is either truncated or split. Anything entirely inside the range
691 * is deleted from the tree.
692 */
693 int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
694 struct btrfs_root *root, struct inode *inode,
695 struct btrfs_path *path, u64 start, u64 end,
696 u64 *drop_end, int drop_cache)
697 {
698 struct extent_buffer *leaf;
699 struct btrfs_file_extent_item *fi;
700 struct btrfs_key key;
701 struct btrfs_key new_key;
702 u64 ino = btrfs_ino(inode);
703 u64 search_start = start;
704 u64 disk_bytenr = 0;
705 u64 num_bytes = 0;
706 u64 extent_offset = 0;
707 u64 extent_end = 0;
708 int del_nr = 0;
709 int del_slot = 0;
710 int extent_type;
711 int recow;
712 int ret;
713 int modify_tree = -1;
714 int update_refs = (root->ref_cows || root == root->fs_info->tree_root);
715 int found = 0;
716
717 if (drop_cache)
718 btrfs_drop_extent_cache(inode, start, end - 1, 0);
719
720 if (start >= BTRFS_I(inode)->disk_i_size)
721 modify_tree = 0;
722
723 while (1) {
724 recow = 0;
725 ret = btrfs_lookup_file_extent(trans, root, path, ino,
726 search_start, modify_tree);
727 if (ret < 0)
728 break;
729 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
730 leaf = path->nodes[0];
731 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
732 if (key.objectid == ino &&
733 key.type == BTRFS_EXTENT_DATA_KEY)
734 path->slots[0]--;
735 }
736 ret = 0;
737 next_slot:
738 leaf = path->nodes[0];
739 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
740 BUG_ON(del_nr > 0);
741 ret = btrfs_next_leaf(root, path);
742 if (ret < 0)
743 break;
744 if (ret > 0) {
745 ret = 0;
746 break;
747 }
748 leaf = path->nodes[0];
749 recow = 1;
750 }
751
752 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
753 if (key.objectid > ino ||
754 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
755 break;
756
757 fi = btrfs_item_ptr(leaf, path->slots[0],
758 struct btrfs_file_extent_item);
759 extent_type = btrfs_file_extent_type(leaf, fi);
760
761 if (extent_type == BTRFS_FILE_EXTENT_REG ||
762 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
763 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
764 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
765 extent_offset = btrfs_file_extent_offset(leaf, fi);
766 extent_end = key.offset +
767 btrfs_file_extent_num_bytes(leaf, fi);
768 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
769 extent_end = key.offset +
770 btrfs_file_extent_inline_len(leaf, fi);
771 } else {
772 WARN_ON(1);
773 extent_end = search_start;
774 }
775
776 if (extent_end <= search_start) {
777 path->slots[0]++;
778 goto next_slot;
779 }
780
781 found = 1;
782 search_start = max(key.offset, start);
783 if (recow || !modify_tree) {
784 modify_tree = -1;
785 btrfs_release_path(path);
786 continue;
787 }
788
789 /*
790 * | - range to drop - |
791 * | -------- extent -------- |
792 */
793 if (start > key.offset && end < extent_end) {
794 BUG_ON(del_nr > 0);
795 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
796
797 memcpy(&new_key, &key, sizeof(new_key));
798 new_key.offset = start;
799 ret = btrfs_duplicate_item(trans, root, path,
800 &new_key);
801 if (ret == -EAGAIN) {
802 btrfs_release_path(path);
803 continue;
804 }
805 if (ret < 0)
806 break;
807
808 leaf = path->nodes[0];
809 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
810 struct btrfs_file_extent_item);
811 btrfs_set_file_extent_num_bytes(leaf, fi,
812 start - key.offset);
813
814 fi = btrfs_item_ptr(leaf, path->slots[0],
815 struct btrfs_file_extent_item);
816
817 extent_offset += start - key.offset;
818 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
819 btrfs_set_file_extent_num_bytes(leaf, fi,
820 extent_end - start);
821 btrfs_mark_buffer_dirty(leaf);
822
823 if (update_refs && disk_bytenr > 0) {
824 ret = btrfs_inc_extent_ref(trans, root,
825 disk_bytenr, num_bytes, 0,
826 root->root_key.objectid,
827 new_key.objectid,
828 start - extent_offset, 0);
829 BUG_ON(ret); /* -ENOMEM */
830 }
831 key.offset = start;
832 }
833 /*
834 * | ---- range to drop ----- |
835 * | -------- extent -------- |
836 */
837 if (start <= key.offset && end < extent_end) {
838 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
839
840 memcpy(&new_key, &key, sizeof(new_key));
841 new_key.offset = end;
842 btrfs_set_item_key_safe(root, path, &new_key);
843
844 extent_offset += end - key.offset;
845 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
846 btrfs_set_file_extent_num_bytes(leaf, fi,
847 extent_end - end);
848 btrfs_mark_buffer_dirty(leaf);
849 if (update_refs && disk_bytenr > 0)
850 inode_sub_bytes(inode, end - key.offset);
851 break;
852 }
853
854 search_start = extent_end;
855 /*
856 * | ---- range to drop ----- |
857 * | -------- extent -------- |
858 */
859 if (start > key.offset && end >= extent_end) {
860 BUG_ON(del_nr > 0);
861 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
862
863 btrfs_set_file_extent_num_bytes(leaf, fi,
864 start - key.offset);
865 btrfs_mark_buffer_dirty(leaf);
866 if (update_refs && disk_bytenr > 0)
867 inode_sub_bytes(inode, extent_end - start);
868 if (end == extent_end)
869 break;
870
871 path->slots[0]++;
872 goto next_slot;
873 }
874
875 /*
876 * | ---- range to drop ----- |
877 * | ------ extent ------ |
878 */
879 if (start <= key.offset && end >= extent_end) {
880 if (del_nr == 0) {
881 del_slot = path->slots[0];
882 del_nr = 1;
883 } else {
884 BUG_ON(del_slot + del_nr != path->slots[0]);
885 del_nr++;
886 }
887
888 if (update_refs &&
889 extent_type == BTRFS_FILE_EXTENT_INLINE) {
890 inode_sub_bytes(inode,
891 extent_end - key.offset);
892 extent_end = ALIGN(extent_end,
893 root->sectorsize);
894 } else if (update_refs && disk_bytenr > 0) {
895 ret = btrfs_free_extent(trans, root,
896 disk_bytenr, num_bytes, 0,
897 root->root_key.objectid,
898 key.objectid, key.offset -
899 extent_offset, 0);
900 BUG_ON(ret); /* -ENOMEM */
901 inode_sub_bytes(inode,
902 extent_end - key.offset);
903 }
904
905 if (end == extent_end)
906 break;
907
908 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
909 path->slots[0]++;
910 goto next_slot;
911 }
912
913 ret = btrfs_del_items(trans, root, path, del_slot,
914 del_nr);
915 if (ret) {
916 btrfs_abort_transaction(trans, root, ret);
917 break;
918 }
919
920 del_nr = 0;
921 del_slot = 0;
922
923 btrfs_release_path(path);
924 continue;
925 }
926
927 BUG_ON(1);
928 }
929
930 if (!ret && del_nr > 0) {
931 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
932 if (ret)
933 btrfs_abort_transaction(trans, root, ret);
934 }
935
936 if (drop_end)
937 *drop_end = found ? min(end, extent_end) : end;
938 btrfs_release_path(path);
939 return ret;
940 }
941
942 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
943 struct btrfs_root *root, struct inode *inode, u64 start,
944 u64 end, int drop_cache)
945 {
946 struct btrfs_path *path;
947 int ret;
948
949 path = btrfs_alloc_path();
950 if (!path)
951 return -ENOMEM;
952 ret = __btrfs_drop_extents(trans, root, inode, path, start, end, NULL,
953 drop_cache);
954 btrfs_free_path(path);
955 return ret;
956 }
957
958 static int extent_mergeable(struct extent_buffer *leaf, int slot,
959 u64 objectid, u64 bytenr, u64 orig_offset,
960 u64 *start, u64 *end)
961 {
962 struct btrfs_file_extent_item *fi;
963 struct btrfs_key key;
964 u64 extent_end;
965
966 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
967 return 0;
968
969 btrfs_item_key_to_cpu(leaf, &key, slot);
970 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
971 return 0;
972
973 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
974 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
975 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
976 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
977 btrfs_file_extent_compression(leaf, fi) ||
978 btrfs_file_extent_encryption(leaf, fi) ||
979 btrfs_file_extent_other_encoding(leaf, fi))
980 return 0;
981
982 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
983 if ((*start && *start != key.offset) || (*end && *end != extent_end))
984 return 0;
985
986 *start = key.offset;
987 *end = extent_end;
988 return 1;
989 }
990
991 /*
992 * Mark extent in the range start - end as written.
993 *
994 * This changes extent type from 'pre-allocated' to 'regular'. If only
995 * part of extent is marked as written, the extent will be split into
996 * two or three.
997 */
998 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
999 struct inode *inode, u64 start, u64 end)
1000 {
1001 struct btrfs_root *root = BTRFS_I(inode)->root;
1002 struct extent_buffer *leaf;
1003 struct btrfs_path *path;
1004 struct btrfs_file_extent_item *fi;
1005 struct btrfs_key key;
1006 struct btrfs_key new_key;
1007 u64 bytenr;
1008 u64 num_bytes;
1009 u64 extent_end;
1010 u64 orig_offset;
1011 u64 other_start;
1012 u64 other_end;
1013 u64 split;
1014 int del_nr = 0;
1015 int del_slot = 0;
1016 int recow;
1017 int ret;
1018 u64 ino = btrfs_ino(inode);
1019
1020 path = btrfs_alloc_path();
1021 if (!path)
1022 return -ENOMEM;
1023 again:
1024 recow = 0;
1025 split = start;
1026 key.objectid = ino;
1027 key.type = BTRFS_EXTENT_DATA_KEY;
1028 key.offset = split;
1029
1030 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1031 if (ret < 0)
1032 goto out;
1033 if (ret > 0 && path->slots[0] > 0)
1034 path->slots[0]--;
1035
1036 leaf = path->nodes[0];
1037 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1038 BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
1039 fi = btrfs_item_ptr(leaf, path->slots[0],
1040 struct btrfs_file_extent_item);
1041 BUG_ON(btrfs_file_extent_type(leaf, fi) !=
1042 BTRFS_FILE_EXTENT_PREALLOC);
1043 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1044 BUG_ON(key.offset > start || extent_end < end);
1045
1046 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1047 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1048 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
1049 memcpy(&new_key, &key, sizeof(new_key));
1050
1051 if (start == key.offset && end < extent_end) {
1052 other_start = 0;
1053 other_end = start;
1054 if (extent_mergeable(leaf, path->slots[0] - 1,
1055 ino, bytenr, orig_offset,
1056 &other_start, &other_end)) {
1057 new_key.offset = end;
1058 btrfs_set_item_key_safe(root, path, &new_key);
1059 fi = btrfs_item_ptr(leaf, path->slots[0],
1060 struct btrfs_file_extent_item);
1061 btrfs_set_file_extent_generation(leaf, fi,
1062 trans->transid);
1063 btrfs_set_file_extent_num_bytes(leaf, fi,
1064 extent_end - end);
1065 btrfs_set_file_extent_offset(leaf, fi,
1066 end - orig_offset);
1067 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1068 struct btrfs_file_extent_item);
1069 btrfs_set_file_extent_generation(leaf, fi,
1070 trans->transid);
1071 btrfs_set_file_extent_num_bytes(leaf, fi,
1072 end - other_start);
1073 btrfs_mark_buffer_dirty(leaf);
1074 goto out;
1075 }
1076 }
1077
1078 if (start > key.offset && end == extent_end) {
1079 other_start = end;
1080 other_end = 0;
1081 if (extent_mergeable(leaf, path->slots[0] + 1,
1082 ino, bytenr, orig_offset,
1083 &other_start, &other_end)) {
1084 fi = btrfs_item_ptr(leaf, path->slots[0],
1085 struct btrfs_file_extent_item);
1086 btrfs_set_file_extent_num_bytes(leaf, fi,
1087 start - key.offset);
1088 btrfs_set_file_extent_generation(leaf, fi,
1089 trans->transid);
1090 path->slots[0]++;
1091 new_key.offset = start;
1092 btrfs_set_item_key_safe(root, path, &new_key);
1093
1094 fi = btrfs_item_ptr(leaf, path->slots[0],
1095 struct btrfs_file_extent_item);
1096 btrfs_set_file_extent_generation(leaf, fi,
1097 trans->transid);
1098 btrfs_set_file_extent_num_bytes(leaf, fi,
1099 other_end - start);
1100 btrfs_set_file_extent_offset(leaf, fi,
1101 start - orig_offset);
1102 btrfs_mark_buffer_dirty(leaf);
1103 goto out;
1104 }
1105 }
1106
1107 while (start > key.offset || end < extent_end) {
1108 if (key.offset == start)
1109 split = end;
1110
1111 new_key.offset = split;
1112 ret = btrfs_duplicate_item(trans, root, path, &new_key);
1113 if (ret == -EAGAIN) {
1114 btrfs_release_path(path);
1115 goto again;
1116 }
1117 if (ret < 0) {
1118 btrfs_abort_transaction(trans, root, ret);
1119 goto out;
1120 }
1121
1122 leaf = path->nodes[0];
1123 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1124 struct btrfs_file_extent_item);
1125 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1126 btrfs_set_file_extent_num_bytes(leaf, fi,
1127 split - key.offset);
1128
1129 fi = btrfs_item_ptr(leaf, path->slots[0],
1130 struct btrfs_file_extent_item);
1131
1132 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1133 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
1134 btrfs_set_file_extent_num_bytes(leaf, fi,
1135 extent_end - split);
1136 btrfs_mark_buffer_dirty(leaf);
1137
1138 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
1139 root->root_key.objectid,
1140 ino, orig_offset, 0);
1141 BUG_ON(ret); /* -ENOMEM */
1142
1143 if (split == start) {
1144 key.offset = start;
1145 } else {
1146 BUG_ON(start != key.offset);
1147 path->slots[0]--;
1148 extent_end = end;
1149 }
1150 recow = 1;
1151 }
1152
1153 other_start = end;
1154 other_end = 0;
1155 if (extent_mergeable(leaf, path->slots[0] + 1,
1156 ino, bytenr, orig_offset,
1157 &other_start, &other_end)) {
1158 if (recow) {
1159 btrfs_release_path(path);
1160 goto again;
1161 }
1162 extent_end = other_end;
1163 del_slot = path->slots[0] + 1;
1164 del_nr++;
1165 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1166 0, root->root_key.objectid,
1167 ino, orig_offset, 0);
1168 BUG_ON(ret); /* -ENOMEM */
1169 }
1170 other_start = 0;
1171 other_end = start;
1172 if (extent_mergeable(leaf, path->slots[0] - 1,
1173 ino, bytenr, orig_offset,
1174 &other_start, &other_end)) {
1175 if (recow) {
1176 btrfs_release_path(path);
1177 goto again;
1178 }
1179 key.offset = other_start;
1180 del_slot = path->slots[0];
1181 del_nr++;
1182 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1183 0, root->root_key.objectid,
1184 ino, orig_offset, 0);
1185 BUG_ON(ret); /* -ENOMEM */
1186 }
1187 if (del_nr == 0) {
1188 fi = btrfs_item_ptr(leaf, path->slots[0],
1189 struct btrfs_file_extent_item);
1190 btrfs_set_file_extent_type(leaf, fi,
1191 BTRFS_FILE_EXTENT_REG);
1192 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1193 btrfs_mark_buffer_dirty(leaf);
1194 } else {
1195 fi = btrfs_item_ptr(leaf, del_slot - 1,
1196 struct btrfs_file_extent_item);
1197 btrfs_set_file_extent_type(leaf, fi,
1198 BTRFS_FILE_EXTENT_REG);
1199 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1200 btrfs_set_file_extent_num_bytes(leaf, fi,
1201 extent_end - key.offset);
1202 btrfs_mark_buffer_dirty(leaf);
1203
1204 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1205 if (ret < 0) {
1206 btrfs_abort_transaction(trans, root, ret);
1207 goto out;
1208 }
1209 }
1210 out:
1211 btrfs_free_path(path);
1212 return 0;
1213 }
1214
1215 /*
1216 * on error we return an unlocked page and the error value
1217 * on success we return a locked page and 0
1218 */
1219 static int prepare_uptodate_page(struct page *page, u64 pos,
1220 bool force_uptodate)
1221 {
1222 int ret = 0;
1223
1224 if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) &&
1225 !PageUptodate(page)) {
1226 ret = btrfs_readpage(NULL, page);
1227 if (ret)
1228 return ret;
1229 lock_page(page);
1230 if (!PageUptodate(page)) {
1231 unlock_page(page);
1232 return -EIO;
1233 }
1234 }
1235 return 0;
1236 }
1237
1238 /*
1239 * this gets pages into the page cache and locks them down, it also properly
1240 * waits for data=ordered extents to finish before allowing the pages to be
1241 * modified.
1242 */
1243 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
1244 struct page **pages, size_t num_pages,
1245 loff_t pos, unsigned long first_index,
1246 size_t write_bytes, bool force_uptodate)
1247 {
1248 struct extent_state *cached_state = NULL;
1249 int i;
1250 unsigned long index = pos >> PAGE_CACHE_SHIFT;
1251 struct inode *inode = file_inode(file);
1252 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1253 int err = 0;
1254 int faili = 0;
1255 u64 start_pos;
1256 u64 last_pos;
1257
1258 start_pos = pos & ~((u64)root->sectorsize - 1);
1259 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
1260
1261 again:
1262 for (i = 0; i < num_pages; i++) {
1263 pages[i] = find_or_create_page(inode->i_mapping, index + i,
1264 mask | __GFP_WRITE);
1265 if (!pages[i]) {
1266 faili = i - 1;
1267 err = -ENOMEM;
1268 goto fail;
1269 }
1270
1271 if (i == 0)
1272 err = prepare_uptodate_page(pages[i], pos,
1273 force_uptodate);
1274 if (i == num_pages - 1)
1275 err = prepare_uptodate_page(pages[i],
1276 pos + write_bytes, false);
1277 if (err) {
1278 page_cache_release(pages[i]);
1279 faili = i - 1;
1280 goto fail;
1281 }
1282 wait_on_page_writeback(pages[i]);
1283 }
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 btrfs_wait_ordered_range(inode, start_pos,
1303 last_pos - start_pos);
1304 goto again;
1305 }
1306 if (ordered)
1307 btrfs_put_ordered_extent(ordered);
1308
1309 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
1310 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1311 EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
1312 0, 0, &cached_state, GFP_NOFS);
1313 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1314 start_pos, last_pos - 1, &cached_state,
1315 GFP_NOFS);
1316 }
1317 for (i = 0; i < num_pages; i++) {
1318 if (clear_page_dirty_for_io(pages[i]))
1319 account_page_redirty(pages[i]);
1320 set_page_extent_mapped(pages[i]);
1321 WARN_ON(!PageLocked(pages[i]));
1322 }
1323 return 0;
1324 fail:
1325 while (faili >= 0) {
1326 unlock_page(pages[faili]);
1327 page_cache_release(pages[faili]);
1328 faili--;
1329 }
1330 return err;
1331
1332 }
1333
1334 static noinline int check_can_nocow(struct inode *inode, loff_t pos,
1335 size_t *write_bytes)
1336 {
1337 struct btrfs_root *root = BTRFS_I(inode)->root;
1338 struct btrfs_ordered_extent *ordered;
1339 u64 lockstart, lockend;
1340 u64 num_bytes;
1341 int ret;
1342
1343 lockstart = round_down(pos, root->sectorsize);
1344 lockend = lockstart + round_up(*write_bytes, root->sectorsize) - 1;
1345
1346 while (1) {
1347 lock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1348 ordered = btrfs_lookup_ordered_range(inode, lockstart,
1349 lockend - lockstart + 1);
1350 if (!ordered) {
1351 break;
1352 }
1353 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1354 btrfs_start_ordered_extent(inode, ordered, 1);
1355 btrfs_put_ordered_extent(ordered);
1356 }
1357
1358 num_bytes = lockend - lockstart + 1;
1359 ret = can_nocow_extent(inode, lockstart, &num_bytes, NULL, NULL, NULL);
1360 if (ret <= 0) {
1361 ret = 0;
1362 } else {
1363 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
1364 EXTENT_DIRTY | EXTENT_DELALLOC |
1365 EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 0, 0,
1366 NULL, GFP_NOFS);
1367 *write_bytes = min_t(size_t, *write_bytes, num_bytes);
1368 }
1369
1370 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1371
1372 return ret;
1373 }
1374
1375 static noinline ssize_t __btrfs_buffered_write(struct file *file,
1376 struct iov_iter *i,
1377 loff_t pos)
1378 {
1379 struct inode *inode = file_inode(file);
1380 struct btrfs_root *root = BTRFS_I(inode)->root;
1381 struct page **pages = NULL;
1382 u64 release_bytes = 0;
1383 unsigned long first_index;
1384 size_t num_written = 0;
1385 int nrptrs;
1386 int ret = 0;
1387 bool only_release_metadata = false;
1388 bool force_page_uptodate = false;
1389
1390 nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
1391 PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
1392 (sizeof(struct page *)));
1393 nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
1394 nrptrs = max(nrptrs, 8);
1395 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1396 if (!pages)
1397 return -ENOMEM;
1398
1399 first_index = pos >> PAGE_CACHE_SHIFT;
1400
1401 while (iov_iter_count(i) > 0) {
1402 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1403 size_t write_bytes = min(iov_iter_count(i),
1404 nrptrs * (size_t)PAGE_CACHE_SIZE -
1405 offset);
1406 size_t num_pages = (write_bytes + offset +
1407 PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1408 size_t reserve_bytes;
1409 size_t dirty_pages;
1410 size_t copied;
1411
1412 WARN_ON(num_pages > nrptrs);
1413
1414 /*
1415 * Fault pages before locking them in prepare_pages
1416 * to avoid recursive lock
1417 */
1418 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1419 ret = -EFAULT;
1420 break;
1421 }
1422
1423 reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
1424 ret = btrfs_check_data_free_space(inode, reserve_bytes);
1425 if (ret == -ENOSPC &&
1426 (BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
1427 BTRFS_INODE_PREALLOC))) {
1428 ret = check_can_nocow(inode, pos, &write_bytes);
1429 if (ret > 0) {
1430 only_release_metadata = true;
1431 /*
1432 * our prealloc extent may be smaller than
1433 * write_bytes, so scale down.
1434 */
1435 num_pages = (write_bytes + offset +
1436 PAGE_CACHE_SIZE - 1) >>
1437 PAGE_CACHE_SHIFT;
1438 reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
1439 ret = 0;
1440 } else {
1441 ret = -ENOSPC;
1442 }
1443 }
1444
1445 if (ret)
1446 break;
1447
1448 ret = btrfs_delalloc_reserve_metadata(inode, reserve_bytes);
1449 if (ret) {
1450 if (!only_release_metadata)
1451 btrfs_free_reserved_data_space(inode,
1452 reserve_bytes);
1453 break;
1454 }
1455
1456 release_bytes = reserve_bytes;
1457
1458 /*
1459 * This is going to setup the pages array with the number of
1460 * pages we want, so we don't really need to worry about the
1461 * contents of pages from loop to loop
1462 */
1463 ret = prepare_pages(root, file, pages, num_pages,
1464 pos, first_index, write_bytes,
1465 force_page_uptodate);
1466 if (ret)
1467 break;
1468
1469 copied = btrfs_copy_from_user(pos, num_pages,
1470 write_bytes, pages, i);
1471
1472 /*
1473 * if we have trouble faulting in the pages, fall
1474 * back to one page at a time
1475 */
1476 if (copied < write_bytes)
1477 nrptrs = 1;
1478
1479 if (copied == 0) {
1480 force_page_uptodate = true;
1481 dirty_pages = 0;
1482 } else {
1483 force_page_uptodate = false;
1484 dirty_pages = (copied + offset +
1485 PAGE_CACHE_SIZE - 1) >>
1486 PAGE_CACHE_SHIFT;
1487 }
1488
1489 /*
1490 * If we had a short copy we need to release the excess delaloc
1491 * bytes we reserved. We need to increment outstanding_extents
1492 * because btrfs_delalloc_release_space will decrement it, but
1493 * we still have an outstanding extent for the chunk we actually
1494 * managed to copy.
1495 */
1496 if (num_pages > dirty_pages) {
1497 release_bytes = (num_pages - dirty_pages) <<
1498 PAGE_CACHE_SHIFT;
1499 if (copied > 0) {
1500 spin_lock(&BTRFS_I(inode)->lock);
1501 BTRFS_I(inode)->outstanding_extents++;
1502 spin_unlock(&BTRFS_I(inode)->lock);
1503 }
1504 if (only_release_metadata)
1505 btrfs_delalloc_release_metadata(inode,
1506 release_bytes);
1507 else
1508 btrfs_delalloc_release_space(inode,
1509 release_bytes);
1510 }
1511
1512 release_bytes = dirty_pages << PAGE_CACHE_SHIFT;
1513 if (copied > 0) {
1514 ret = btrfs_dirty_pages(root, inode, pages,
1515 dirty_pages, pos, copied,
1516 NULL);
1517 if (ret) {
1518 btrfs_drop_pages(pages, num_pages);
1519 break;
1520 }
1521 }
1522
1523 release_bytes = 0;
1524 btrfs_drop_pages(pages, num_pages);
1525
1526 if (only_release_metadata && copied > 0) {
1527 u64 lockstart = round_down(pos, root->sectorsize);
1528 u64 lockend = lockstart +
1529 (dirty_pages << PAGE_CACHE_SHIFT) - 1;
1530
1531 set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
1532 lockend, EXTENT_NORESERVE, NULL,
1533 NULL, GFP_NOFS);
1534 only_release_metadata = false;
1535 }
1536
1537 cond_resched();
1538
1539 balance_dirty_pages_ratelimited(inode->i_mapping);
1540 if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1541 btrfs_btree_balance_dirty(root);
1542
1543 pos += copied;
1544 num_written += copied;
1545 }
1546
1547 kfree(pages);
1548
1549 if (release_bytes) {
1550 if (only_release_metadata)
1551 btrfs_delalloc_release_metadata(inode, release_bytes);
1552 else
1553 btrfs_delalloc_release_space(inode, release_bytes);
1554 }
1555
1556 return num_written ? num_written : ret;
1557 }
1558
1559 static ssize_t __btrfs_direct_write(struct kiocb *iocb,
1560 const struct iovec *iov,
1561 unsigned long nr_segs, loff_t pos,
1562 loff_t *ppos, size_t count, size_t ocount)
1563 {
1564 struct file *file = iocb->ki_filp;
1565 struct iov_iter i;
1566 ssize_t written;
1567 ssize_t written_buffered;
1568 loff_t endbyte;
1569 int err;
1570
1571 written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
1572 count, ocount);
1573
1574 if (written < 0 || written == count)
1575 return written;
1576
1577 pos += written;
1578 count -= written;
1579 iov_iter_init(&i, iov, nr_segs, count, written);
1580 written_buffered = __btrfs_buffered_write(file, &i, pos);
1581 if (written_buffered < 0) {
1582 err = written_buffered;
1583 goto out;
1584 }
1585 endbyte = pos + written_buffered - 1;
1586 err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
1587 if (err)
1588 goto out;
1589 written += written_buffered;
1590 *ppos = pos + written_buffered;
1591 invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
1592 endbyte >> PAGE_CACHE_SHIFT);
1593 out:
1594 return written ? written : err;
1595 }
1596
1597 static void update_time_for_write(struct inode *inode)
1598 {
1599 struct timespec now;
1600
1601 if (IS_NOCMTIME(inode))
1602 return;
1603
1604 now = current_fs_time(inode->i_sb);
1605 if (!timespec_equal(&inode->i_mtime, &now))
1606 inode->i_mtime = now;
1607
1608 if (!timespec_equal(&inode->i_ctime, &now))
1609 inode->i_ctime = now;
1610
1611 if (IS_I_VERSION(inode))
1612 inode_inc_iversion(inode);
1613 }
1614
1615 static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
1616 const struct iovec *iov,
1617 unsigned long nr_segs, loff_t pos)
1618 {
1619 struct file *file = iocb->ki_filp;
1620 struct inode *inode = file_inode(file);
1621 struct btrfs_root *root = BTRFS_I(inode)->root;
1622 loff_t *ppos = &iocb->ki_pos;
1623 u64 start_pos;
1624 ssize_t num_written = 0;
1625 ssize_t err = 0;
1626 size_t count, ocount;
1627 bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
1628
1629 mutex_lock(&inode->i_mutex);
1630
1631 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1632 if (err) {
1633 mutex_unlock(&inode->i_mutex);
1634 goto out;
1635 }
1636 count = ocount;
1637
1638 current->backing_dev_info = inode->i_mapping->backing_dev_info;
1639 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1640 if (err) {
1641 mutex_unlock(&inode->i_mutex);
1642 goto out;
1643 }
1644
1645 if (count == 0) {
1646 mutex_unlock(&inode->i_mutex);
1647 goto out;
1648 }
1649
1650 err = file_remove_suid(file);
1651 if (err) {
1652 mutex_unlock(&inode->i_mutex);
1653 goto out;
1654 }
1655
1656 /*
1657 * If BTRFS flips readonly due to some impossible error
1658 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1659 * although we have opened a file as writable, we have
1660 * to stop this write operation to ensure FS consistency.
1661 */
1662 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1663 mutex_unlock(&inode->i_mutex);
1664 err = -EROFS;
1665 goto out;
1666 }
1667
1668 /*
1669 * We reserve space for updating the inode when we reserve space for the
1670 * extent we are going to write, so we will enospc out there. We don't
1671 * need to start yet another transaction to update the inode as we will
1672 * update the inode when we finish writing whatever data we write.
1673 */
1674 update_time_for_write(inode);
1675
1676 start_pos = round_down(pos, root->sectorsize);
1677 if (start_pos > i_size_read(inode)) {
1678 err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
1679 if (err) {
1680 mutex_unlock(&inode->i_mutex);
1681 goto out;
1682 }
1683 }
1684
1685 if (sync)
1686 atomic_inc(&BTRFS_I(inode)->sync_writers);
1687
1688 if (unlikely(file->f_flags & O_DIRECT)) {
1689 num_written = __btrfs_direct_write(iocb, iov, nr_segs,
1690 pos, ppos, count, ocount);
1691 } else {
1692 struct iov_iter i;
1693
1694 iov_iter_init(&i, iov, nr_segs, count, num_written);
1695
1696 num_written = __btrfs_buffered_write(file, &i, pos);
1697 if (num_written > 0)
1698 *ppos = pos + num_written;
1699 }
1700
1701 mutex_unlock(&inode->i_mutex);
1702
1703 /*
1704 * we want to make sure fsync finds this change
1705 * but we haven't joined a transaction running right now.
1706 *
1707 * Later on, someone is sure to update the inode and get the
1708 * real transid recorded.
1709 *
1710 * We set last_trans now to the fs_info generation + 1,
1711 * this will either be one more than the running transaction
1712 * or the generation used for the next transaction if there isn't
1713 * one running right now.
1714 *
1715 * We also have to set last_sub_trans to the current log transid,
1716 * otherwise subsequent syncs to a file that's been synced in this
1717 * transaction will appear to have already occured.
1718 */
1719 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1720 BTRFS_I(inode)->last_sub_trans = root->log_transid;
1721 if (num_written > 0) {
1722 err = generic_write_sync(file, pos, num_written);
1723 if (err < 0 && num_written > 0)
1724 num_written = err;
1725 }
1726
1727 if (sync)
1728 atomic_dec(&BTRFS_I(inode)->sync_writers);
1729 out:
1730 current->backing_dev_info = NULL;
1731 return num_written ? num_written : err;
1732 }
1733
1734 int btrfs_release_file(struct inode *inode, struct file *filp)
1735 {
1736 /*
1737 * ordered_data_close is set by settattr when we are about to truncate
1738 * a file from a non-zero size to a zero size. This tries to
1739 * flush down new bytes that may have been written if the
1740 * application were using truncate to replace a file in place.
1741 */
1742 if (test_and_clear_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
1743 &BTRFS_I(inode)->runtime_flags)) {
1744 struct btrfs_trans_handle *trans;
1745 struct btrfs_root *root = BTRFS_I(inode)->root;
1746
1747 /*
1748 * We need to block on a committing transaction to keep us from
1749 * throwing a ordered operation on to the list and causing
1750 * something like sync to deadlock trying to flush out this
1751 * inode.
1752 */
1753 trans = btrfs_start_transaction(root, 0);
1754 if (IS_ERR(trans))
1755 return PTR_ERR(trans);
1756 btrfs_add_ordered_operation(trans, BTRFS_I(inode)->root, inode);
1757 btrfs_end_transaction(trans, root);
1758 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1759 filemap_flush(inode->i_mapping);
1760 }
1761 if (filp->private_data)
1762 btrfs_ioctl_trans_end(filp);
1763 return 0;
1764 }
1765
1766 /*
1767 * fsync call for both files and directories. This logs the inode into
1768 * the tree log instead of forcing full commits whenever possible.
1769 *
1770 * It needs to call filemap_fdatawait so that all ordered extent updates are
1771 * in the metadata btree are up to date for copying to the log.
1772 *
1773 * It drops the inode mutex before doing the tree log commit. This is an
1774 * important optimization for directories because holding the mutex prevents
1775 * new operations on the dir while we write to disk.
1776 */
1777 int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
1778 {
1779 struct dentry *dentry = file->f_path.dentry;
1780 struct inode *inode = dentry->d_inode;
1781 struct btrfs_root *root = BTRFS_I(inode)->root;
1782 int ret = 0;
1783 struct btrfs_trans_handle *trans;
1784 bool full_sync = 0;
1785
1786 trace_btrfs_sync_file(file, datasync);
1787
1788 /*
1789 * We write the dirty pages in the range and wait until they complete
1790 * out of the ->i_mutex. If so, we can flush the dirty pages by
1791 * multi-task, and make the performance up. See
1792 * btrfs_wait_ordered_range for an explanation of the ASYNC check.
1793 */
1794 atomic_inc(&BTRFS_I(inode)->sync_writers);
1795 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
1796 if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1797 &BTRFS_I(inode)->runtime_flags))
1798 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
1799 atomic_dec(&BTRFS_I(inode)->sync_writers);
1800 if (ret)
1801 return ret;
1802
1803 mutex_lock(&inode->i_mutex);
1804
1805 /*
1806 * We flush the dirty pages again to avoid some dirty pages in the
1807 * range being left.
1808 */
1809 atomic_inc(&root->log_batch);
1810 full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1811 &BTRFS_I(inode)->runtime_flags);
1812 if (full_sync)
1813 btrfs_wait_ordered_range(inode, start, end - start + 1);
1814 atomic_inc(&root->log_batch);
1815
1816 /*
1817 * check the transaction that last modified this inode
1818 * and see if its already been committed
1819 */
1820 if (!BTRFS_I(inode)->last_trans) {
1821 mutex_unlock(&inode->i_mutex);
1822 goto out;
1823 }
1824
1825 /*
1826 * if the last transaction that changed this file was before
1827 * the current transaction, we can bail out now without any
1828 * syncing
1829 */
1830 smp_mb();
1831 if (btrfs_inode_in_log(inode, root->fs_info->generation) ||
1832 BTRFS_I(inode)->last_trans <=
1833 root->fs_info->last_trans_committed) {
1834 BTRFS_I(inode)->last_trans = 0;
1835
1836 /*
1837 * We'v had everything committed since the last time we were
1838 * modified so clear this flag in case it was set for whatever
1839 * reason, it's no longer relevant.
1840 */
1841 clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1842 &BTRFS_I(inode)->runtime_flags);
1843 mutex_unlock(&inode->i_mutex);
1844 goto out;
1845 }
1846
1847 /*
1848 * ok we haven't committed the transaction yet, lets do a commit
1849 */
1850 if (file->private_data)
1851 btrfs_ioctl_trans_end(file);
1852
1853 trans = btrfs_start_transaction(root, 0);
1854 if (IS_ERR(trans)) {
1855 ret = PTR_ERR(trans);
1856 mutex_unlock(&inode->i_mutex);
1857 goto out;
1858 }
1859
1860 ret = btrfs_log_dentry_safe(trans, root, dentry);
1861 if (ret < 0) {
1862 /* Fallthrough and commit/free transaction. */
1863 ret = 1;
1864 }
1865
1866 /* we've logged all the items and now have a consistent
1867 * version of the file in the log. It is possible that
1868 * someone will come in and modify the file, but that's
1869 * fine because the log is consistent on disk, and we
1870 * have references to all of the file's extents
1871 *
1872 * It is possible that someone will come in and log the
1873 * file again, but that will end up using the synchronization
1874 * inside btrfs_sync_log to keep things safe.
1875 */
1876 mutex_unlock(&inode->i_mutex);
1877
1878 if (ret != BTRFS_NO_LOG_SYNC) {
1879 if (ret > 0) {
1880 /*
1881 * If we didn't already wait for ordered extents we need
1882 * to do that now.
1883 */
1884 if (!full_sync)
1885 btrfs_wait_ordered_range(inode, start,
1886 end - start + 1);
1887 ret = btrfs_commit_transaction(trans, root);
1888 } else {
1889 ret = btrfs_sync_log(trans, root);
1890 if (ret == 0) {
1891 ret = btrfs_end_transaction(trans, root);
1892 } else {
1893 if (!full_sync)
1894 btrfs_wait_ordered_range(inode, start,
1895 end -
1896 start + 1);
1897 ret = btrfs_commit_transaction(trans, root);
1898 }
1899 }
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 btrfs_wait_ordered_range(inode, offset, len);
2071
2072 mutex_lock(&inode->i_mutex);
2073 /*
2074 * We needn't truncate any page which is beyond the end of the file
2075 * because we are sure there is no data there.
2076 */
2077 /*
2078 * Only do this if we are in the same page and we aren't doing the
2079 * entire page.
2080 */
2081 if (same_page && len < PAGE_CACHE_SIZE) {
2082 if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE))
2083 ret = btrfs_truncate_page(inode, offset, len, 0);
2084 mutex_unlock(&inode->i_mutex);
2085 return ret;
2086 }
2087
2088 /* zero back part of the first page */
2089 if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE)) {
2090 ret = btrfs_truncate_page(inode, offset, 0, 0);
2091 if (ret) {
2092 mutex_unlock(&inode->i_mutex);
2093 return ret;
2094 }
2095 }
2096
2097 /* zero the front end of the last page */
2098 if (offset + len < round_up(inode->i_size, PAGE_CACHE_SIZE)) {
2099 ret = btrfs_truncate_page(inode, offset + len, 0, 1);
2100 if (ret) {
2101 mutex_unlock(&inode->i_mutex);
2102 return ret;
2103 }
2104 }
2105
2106 if (lockend < lockstart) {
2107 mutex_unlock(&inode->i_mutex);
2108 return 0;
2109 }
2110
2111 while (1) {
2112 struct btrfs_ordered_extent *ordered;
2113
2114 truncate_pagecache_range(inode, lockstart, lockend);
2115
2116 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2117 0, &cached_state);
2118 ordered = btrfs_lookup_first_ordered_extent(inode, lockend);
2119
2120 /*
2121 * We need to make sure we have no ordered extents in this range
2122 * and nobody raced in and read a page in this range, if we did
2123 * we need to try again.
2124 */
2125 if ((!ordered ||
2126 (ordered->file_offset + ordered->len < lockstart ||
2127 ordered->file_offset > lockend)) &&
2128 !test_range_bit(&BTRFS_I(inode)->io_tree, lockstart,
2129 lockend, EXTENT_UPTODATE, 0,
2130 cached_state)) {
2131 if (ordered)
2132 btrfs_put_ordered_extent(ordered);
2133 break;
2134 }
2135 if (ordered)
2136 btrfs_put_ordered_extent(ordered);
2137 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
2138 lockend, &cached_state, GFP_NOFS);
2139 btrfs_wait_ordered_range(inode, lockstart,
2140 lockend - lockstart + 1);
2141 }
2142
2143 path = btrfs_alloc_path();
2144 if (!path) {
2145 ret = -ENOMEM;
2146 goto out;
2147 }
2148
2149 rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
2150 if (!rsv) {
2151 ret = -ENOMEM;
2152 goto out_free;
2153 }
2154 rsv->size = btrfs_calc_trunc_metadata_size(root, 1);
2155 rsv->failfast = 1;
2156
2157 /*
2158 * 1 - update the inode
2159 * 1 - removing the extents in the range
2160 * 1 - adding the hole extent
2161 */
2162 trans = btrfs_start_transaction(root, 3);
2163 if (IS_ERR(trans)) {
2164 err = PTR_ERR(trans);
2165 goto out_free;
2166 }
2167
2168 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
2169 min_size);
2170 BUG_ON(ret);
2171 trans->block_rsv = rsv;
2172
2173 while (cur_offset < lockend) {
2174 ret = __btrfs_drop_extents(trans, root, inode, path,
2175 cur_offset, lockend + 1,
2176 &drop_end, 1);
2177 if (ret != -ENOSPC)
2178 break;
2179
2180 trans->block_rsv = &root->fs_info->trans_block_rsv;
2181
2182 ret = fill_holes(trans, inode, path, cur_offset, drop_end);
2183 if (ret) {
2184 err = ret;
2185 break;
2186 }
2187
2188 cur_offset = drop_end;
2189
2190 ret = btrfs_update_inode(trans, root, inode);
2191 if (ret) {
2192 err = ret;
2193 break;
2194 }
2195
2196 btrfs_end_transaction(trans, root);
2197 btrfs_btree_balance_dirty(root);
2198
2199 trans = btrfs_start_transaction(root, 3);
2200 if (IS_ERR(trans)) {
2201 ret = PTR_ERR(trans);
2202 trans = NULL;
2203 break;
2204 }
2205
2206 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
2207 rsv, min_size);
2208 BUG_ON(ret); /* shouldn't happen */
2209 trans->block_rsv = rsv;
2210 }
2211
2212 if (ret) {
2213 err = ret;
2214 goto out_trans;
2215 }
2216
2217 trans->block_rsv = &root->fs_info->trans_block_rsv;
2218 ret = fill_holes(trans, inode, path, cur_offset, drop_end);
2219 if (ret) {
2220 err = ret;
2221 goto out_trans;
2222 }
2223
2224 out_trans:
2225 if (!trans)
2226 goto out_free;
2227
2228 inode_inc_iversion(inode);
2229 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
2230
2231 trans->block_rsv = &root->fs_info->trans_block_rsv;
2232 ret = btrfs_update_inode(trans, root, inode);
2233 btrfs_end_transaction(trans, root);
2234 btrfs_btree_balance_dirty(root);
2235 out_free:
2236 btrfs_free_path(path);
2237 btrfs_free_block_rsv(root, rsv);
2238 out:
2239 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2240 &cached_state, GFP_NOFS);
2241 mutex_unlock(&inode->i_mutex);
2242 if (ret && !err)
2243 err = ret;
2244 return err;
2245 }
2246
2247 static long btrfs_fallocate(struct file *file, int mode,
2248 loff_t offset, loff_t len)
2249 {
2250 struct inode *inode = file_inode(file);
2251 struct extent_state *cached_state = NULL;
2252 struct btrfs_root *root = BTRFS_I(inode)->root;
2253 u64 cur_offset;
2254 u64 last_byte;
2255 u64 alloc_start;
2256 u64 alloc_end;
2257 u64 alloc_hint = 0;
2258 u64 locked_end;
2259 struct extent_map *em;
2260 int blocksize = BTRFS_I(inode)->root->sectorsize;
2261 int ret;
2262
2263 alloc_start = round_down(offset, blocksize);
2264 alloc_end = round_up(offset + len, blocksize);
2265
2266 /* Make sure we aren't being give some crap mode */
2267 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
2268 return -EOPNOTSUPP;
2269
2270 if (mode & FALLOC_FL_PUNCH_HOLE)
2271 return btrfs_punch_hole(inode, offset, len);
2272
2273 /*
2274 * Make sure we have enough space before we do the
2275 * allocation.
2276 */
2277 ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
2278 if (ret)
2279 return ret;
2280 if (root->fs_info->quota_enabled) {
2281 ret = btrfs_qgroup_reserve(root, alloc_end - alloc_start);
2282 if (ret)
2283 goto out_reserve_fail;
2284 }
2285
2286 mutex_lock(&inode->i_mutex);
2287 ret = inode_newsize_ok(inode, alloc_end);
2288 if (ret)
2289 goto out;
2290
2291 if (alloc_start > inode->i_size) {
2292 ret = btrfs_cont_expand(inode, i_size_read(inode),
2293 alloc_start);
2294 if (ret)
2295 goto out;
2296 } else {
2297 /*
2298 * If we are fallocating from the end of the file onward we
2299 * need to zero out the end of the page if i_size lands in the
2300 * middle of a page.
2301 */
2302 ret = btrfs_truncate_page(inode, inode->i_size, 0, 0);
2303 if (ret)
2304 goto out;
2305 }
2306
2307 /*
2308 * wait for ordered IO before we have any locks. We'll loop again
2309 * below with the locks held.
2310 */
2311 btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
2312
2313 locked_end = alloc_end - 1;
2314 while (1) {
2315 struct btrfs_ordered_extent *ordered;
2316
2317 /* the extent lock is ordered inside the running
2318 * transaction
2319 */
2320 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
2321 locked_end, 0, &cached_state);
2322 ordered = btrfs_lookup_first_ordered_extent(inode,
2323 alloc_end - 1);
2324 if (ordered &&
2325 ordered->file_offset + ordered->len > alloc_start &&
2326 ordered->file_offset < alloc_end) {
2327 btrfs_put_ordered_extent(ordered);
2328 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
2329 alloc_start, locked_end,
2330 &cached_state, GFP_NOFS);
2331 /*
2332 * we can't wait on the range with the transaction
2333 * running or with the extent lock held
2334 */
2335 btrfs_wait_ordered_range(inode, alloc_start,
2336 alloc_end - alloc_start);
2337 } else {
2338 if (ordered)
2339 btrfs_put_ordered_extent(ordered);
2340 break;
2341 }
2342 }
2343
2344 cur_offset = alloc_start;
2345 while (1) {
2346 u64 actual_end;
2347
2348 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
2349 alloc_end - cur_offset, 0);
2350 if (IS_ERR_OR_NULL(em)) {
2351 if (!em)
2352 ret = -ENOMEM;
2353 else
2354 ret = PTR_ERR(em);
2355 break;
2356 }
2357 last_byte = min(extent_map_end(em), alloc_end);
2358 actual_end = min_t(u64, extent_map_end(em), offset + len);
2359 last_byte = ALIGN(last_byte, blocksize);
2360
2361 if (em->block_start == EXTENT_MAP_HOLE ||
2362 (cur_offset >= inode->i_size &&
2363 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
2364 ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
2365 last_byte - cur_offset,
2366 1 << inode->i_blkbits,
2367 offset + len,
2368 &alloc_hint);
2369
2370 if (ret < 0) {
2371 free_extent_map(em);
2372 break;
2373 }
2374 } else if (actual_end > inode->i_size &&
2375 !(mode & FALLOC_FL_KEEP_SIZE)) {
2376 /*
2377 * We didn't need to allocate any more space, but we
2378 * still extended the size of the file so we need to
2379 * update i_size.
2380 */
2381 inode->i_ctime = CURRENT_TIME;
2382 i_size_write(inode, actual_end);
2383 btrfs_ordered_update_i_size(inode, actual_end, NULL);
2384 }
2385 free_extent_map(em);
2386
2387 cur_offset = last_byte;
2388 if (cur_offset >= alloc_end) {
2389 ret = 0;
2390 break;
2391 }
2392 }
2393 unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
2394 &cached_state, GFP_NOFS);
2395 out:
2396 mutex_unlock(&inode->i_mutex);
2397 if (root->fs_info->quota_enabled)
2398 btrfs_qgroup_free(root, alloc_end - alloc_start);
2399 out_reserve_fail:
2400 /* Let go of our reservation. */
2401 btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
2402 return ret;
2403 }
2404
2405 static int find_desired_extent(struct inode *inode, loff_t *offset, int whence)
2406 {
2407 struct btrfs_root *root = BTRFS_I(inode)->root;
2408 struct extent_map *em;
2409 struct extent_state *cached_state = NULL;
2410 u64 lockstart = *offset;
2411 u64 lockend = i_size_read(inode);
2412 u64 start = *offset;
2413 u64 orig_start = *offset;
2414 u64 len = i_size_read(inode);
2415 u64 last_end = 0;
2416 int ret = 0;
2417
2418 lockend = max_t(u64, root->sectorsize, lockend);
2419 if (lockend <= lockstart)
2420 lockend = lockstart + root->sectorsize;
2421
2422 lockend--;
2423 len = lockend - lockstart + 1;
2424
2425 len = max_t(u64, len, root->sectorsize);
2426 if (inode->i_size == 0)
2427 return -ENXIO;
2428
2429 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0,
2430 &cached_state);
2431
2432 /*
2433 * Delalloc is such a pain. If we have a hole and we have pending
2434 * delalloc for a portion of the hole we will get back a hole that
2435 * exists for the entire range since it hasn't been actually written
2436 * yet. So to take care of this case we need to look for an extent just
2437 * before the position we want in case there is outstanding delalloc
2438 * going on here.
2439 */
2440 if (whence == SEEK_HOLE && start != 0) {
2441 if (start <= root->sectorsize)
2442 em = btrfs_get_extent_fiemap(inode, NULL, 0, 0,
2443 root->sectorsize, 0);
2444 else
2445 em = btrfs_get_extent_fiemap(inode, NULL, 0,
2446 start - root->sectorsize,
2447 root->sectorsize, 0);
2448 if (IS_ERR(em)) {
2449 ret = PTR_ERR(em);
2450 goto out;
2451 }
2452 last_end = em->start + em->len;
2453 if (em->block_start == EXTENT_MAP_DELALLOC)
2454 last_end = min_t(u64, last_end, inode->i_size);
2455 free_extent_map(em);
2456 }
2457
2458 while (1) {
2459 em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
2460 if (IS_ERR(em)) {
2461 ret = PTR_ERR(em);
2462 break;
2463 }
2464
2465 if (em->block_start == EXTENT_MAP_HOLE) {
2466 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
2467 if (last_end <= orig_start) {
2468 free_extent_map(em);
2469 ret = -ENXIO;
2470 break;
2471 }
2472 }
2473
2474 if (whence == SEEK_HOLE) {
2475 *offset = start;
2476 free_extent_map(em);
2477 break;
2478 }
2479 } else {
2480 if (whence == SEEK_DATA) {
2481 if (em->block_start == EXTENT_MAP_DELALLOC) {
2482 if (start >= inode->i_size) {
2483 free_extent_map(em);
2484 ret = -ENXIO;
2485 break;
2486 }
2487 }
2488
2489 if (!test_bit(EXTENT_FLAG_PREALLOC,
2490 &em->flags)) {
2491 *offset = start;
2492 free_extent_map(em);
2493 break;
2494 }
2495 }
2496 }
2497
2498 start = em->start + em->len;
2499 last_end = em->start + em->len;
2500
2501 if (em->block_start == EXTENT_MAP_DELALLOC)
2502 last_end = min_t(u64, last_end, inode->i_size);
2503
2504 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
2505 free_extent_map(em);
2506 ret = -ENXIO;
2507 break;
2508 }
2509 free_extent_map(em);
2510 cond_resched();
2511 }
2512 if (!ret)
2513 *offset = min(*offset, inode->i_size);
2514 out:
2515 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2516 &cached_state, GFP_NOFS);
2517 return ret;
2518 }
2519
2520 static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
2521 {
2522 struct inode *inode = file->f_mapping->host;
2523 int ret;
2524
2525 mutex_lock(&inode->i_mutex);
2526 switch (whence) {
2527 case SEEK_END:
2528 case SEEK_CUR:
2529 offset = generic_file_llseek(file, offset, whence);
2530 goto out;
2531 case SEEK_DATA:
2532 case SEEK_HOLE:
2533 if (offset >= i_size_read(inode)) {
2534 mutex_unlock(&inode->i_mutex);
2535 return -ENXIO;
2536 }
2537
2538 ret = find_desired_extent(inode, &offset, whence);
2539 if (ret) {
2540 mutex_unlock(&inode->i_mutex);
2541 return ret;
2542 }
2543 }
2544
2545 offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
2546 out:
2547 mutex_unlock(&inode->i_mutex);
2548 return offset;
2549 }
2550
2551 const struct file_operations btrfs_file_operations = {
2552 .llseek = btrfs_file_llseek,
2553 .read = do_sync_read,
2554 .write = do_sync_write,
2555 .aio_read = generic_file_aio_read,
2556 .splice_read = generic_file_splice_read,
2557 .aio_write = btrfs_file_aio_write,
2558 .mmap = btrfs_file_mmap,
2559 .open = generic_file_open,
2560 .release = btrfs_release_file,
2561 .fsync = btrfs_sync_file,
2562 .fallocate = btrfs_fallocate,
2563 .unlocked_ioctl = btrfs_ioctl,
2564 #ifdef CONFIG_COMPAT
2565 .compat_ioctl = btrfs_ioctl,
2566 #endif
2567 };
2568
2569 void btrfs_auto_defrag_exit(void)
2570 {
2571 if (btrfs_inode_defrag_cachep)
2572 kmem_cache_destroy(btrfs_inode_defrag_cachep);
2573 }
2574
2575 int btrfs_auto_defrag_init(void)
2576 {
2577 btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
2578 sizeof(struct inode_defrag), 0,
2579 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
2580 NULL);
2581 if (!btrfs_inode_defrag_cachep)
2582 return -ENOMEM;
2583
2584 return 0;
2585 }
Linux kernel - Deliverables
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