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dmaengine: imx-dma: fix slow path issue in prep_dma_cyclic
[linux/fpc-iii.git] / fs / btrfs / file.c
blob8e686a427ce2e8e5e824419321f1f8f2dfe19acb
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_trans_handle *trans;
1338 struct btrfs_root *root = BTRFS_I(inode)->root;
1339 struct btrfs_ordered_extent *ordered;
1340 u64 lockstart, lockend;
1341 u64 num_bytes;
1342 int ret;
1343
1344 lockstart = round_down(pos, root->sectorsize);
1345 lockend = lockstart + round_up(*write_bytes, root->sectorsize) - 1;
1346
1347 while (1) {
1348 lock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1349 ordered = btrfs_lookup_ordered_range(inode, lockstart,
1350 lockend - lockstart + 1);
1351 if (!ordered) {
1352 break;
1353 }
1354 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1355 btrfs_start_ordered_extent(inode, ordered, 1);
1356 btrfs_put_ordered_extent(ordered);
1357 }
1358
1359 trans = btrfs_join_transaction(root);
1360 if (IS_ERR(trans)) {
1361 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1362 return PTR_ERR(trans);
1363 }
1364
1365 num_bytes = lockend - lockstart + 1;
1366 ret = can_nocow_extent(trans, inode, lockstart, &num_bytes, NULL, NULL,
1367 NULL);
1368 btrfs_end_transaction(trans, root);
1369 if (ret <= 0) {
1370 ret = 0;
1371 } else {
1372 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
1373 EXTENT_DIRTY | EXTENT_DELALLOC |
1374 EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 0, 0,
1375 NULL, GFP_NOFS);
1376 *write_bytes = min_t(size_t, *write_bytes, num_bytes);
1377 }
1378
1379 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1380
1381 return ret;
1382 }
1383
1384 static noinline ssize_t __btrfs_buffered_write(struct file *file,
1385 struct iov_iter *i,
1386 loff_t pos)
1387 {
1388 struct inode *inode = file_inode(file);
1389 struct btrfs_root *root = BTRFS_I(inode)->root;
1390 struct page **pages = NULL;
1391 u64 release_bytes = 0;
1392 unsigned long first_index;
1393 size_t num_written = 0;
1394 int nrptrs;
1395 int ret = 0;
1396 bool only_release_metadata = false;
1397 bool force_page_uptodate = false;
1398
1399 nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
1400 PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
1401 (sizeof(struct page *)));
1402 nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
1403 nrptrs = max(nrptrs, 8);
1404 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1405 if (!pages)
1406 return -ENOMEM;
1407
1408 first_index = pos >> PAGE_CACHE_SHIFT;
1409
1410 while (iov_iter_count(i) > 0) {
1411 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1412 size_t write_bytes = min(iov_iter_count(i),
1413 nrptrs * (size_t)PAGE_CACHE_SIZE -
1414 offset);
1415 size_t num_pages = (write_bytes + offset +
1416 PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1417 size_t reserve_bytes;
1418 size_t dirty_pages;
1419 size_t copied;
1420
1421 WARN_ON(num_pages > nrptrs);
1422
1423 /*
1424 * Fault pages before locking them in prepare_pages
1425 * to avoid recursive lock
1426 */
1427 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1428 ret = -EFAULT;
1429 break;
1430 }
1431
1432 reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
1433 ret = btrfs_check_data_free_space(inode, reserve_bytes);
1434 if (ret == -ENOSPC &&
1435 (BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
1436 BTRFS_INODE_PREALLOC))) {
1437 ret = check_can_nocow(inode, pos, &write_bytes);
1438 if (ret > 0) {
1439 only_release_metadata = true;
1440 /*
1441 * our prealloc extent may be smaller than
1442 * write_bytes, so scale down.
1443 */
1444 num_pages = (write_bytes + offset +
1445 PAGE_CACHE_SIZE - 1) >>
1446 PAGE_CACHE_SHIFT;
1447 reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
1448 ret = 0;
1449 } else {
1450 ret = -ENOSPC;
1451 }
1452 }
1453
1454 if (ret)
1455 break;
1456
1457 ret = btrfs_delalloc_reserve_metadata(inode, reserve_bytes);
1458 if (ret) {
1459 if (!only_release_metadata)
1460 btrfs_free_reserved_data_space(inode,
1461 reserve_bytes);
1462 break;
1463 }
1464
1465 release_bytes = reserve_bytes;
1466
1467 /*
1468 * This is going to setup the pages array with the number of
1469 * pages we want, so we don't really need to worry about the
1470 * contents of pages from loop to loop
1471 */
1472 ret = prepare_pages(root, file, pages, num_pages,
1473 pos, first_index, write_bytes,
1474 force_page_uptodate);
1475 if (ret)
1476 break;
1477
1478 copied = btrfs_copy_from_user(pos, num_pages,
1479 write_bytes, pages, i);
1480
1481 /*
1482 * if we have trouble faulting in the pages, fall
1483 * back to one page at a time
1484 */
1485 if (copied < write_bytes)
1486 nrptrs = 1;
1487
1488 if (copied == 0) {
1489 force_page_uptodate = true;
1490 dirty_pages = 0;
1491 } else {
1492 force_page_uptodate = false;
1493 dirty_pages = (copied + offset +
1494 PAGE_CACHE_SIZE - 1) >>
1495 PAGE_CACHE_SHIFT;
1496 }
1497
1498 /*
1499 * If we had a short copy we need to release the excess delaloc
1500 * bytes we reserved. We need to increment outstanding_extents
1501 * because btrfs_delalloc_release_space will decrement it, but
1502 * we still have an outstanding extent for the chunk we actually
1503 * managed to copy.
1504 */
1505 if (num_pages > dirty_pages) {
1506 release_bytes = (num_pages - dirty_pages) <<
1507 PAGE_CACHE_SHIFT;
1508 if (copied > 0) {
1509 spin_lock(&BTRFS_I(inode)->lock);
1510 BTRFS_I(inode)->outstanding_extents++;
1511 spin_unlock(&BTRFS_I(inode)->lock);
1512 }
1513 if (only_release_metadata)
1514 btrfs_delalloc_release_metadata(inode,
1515 release_bytes);
1516 else
1517 btrfs_delalloc_release_space(inode,
1518 release_bytes);
1519 }
1520
1521 release_bytes = dirty_pages << PAGE_CACHE_SHIFT;
1522 if (copied > 0) {
1523 ret = btrfs_dirty_pages(root, inode, pages,
1524 dirty_pages, pos, copied,
1525 NULL);
1526 if (ret) {
1527 btrfs_drop_pages(pages, num_pages);
1528 break;
1529 }
1530 }
1531
1532 release_bytes = 0;
1533 btrfs_drop_pages(pages, num_pages);
1534
1535 if (only_release_metadata && copied > 0) {
1536 u64 lockstart = round_down(pos, root->sectorsize);
1537 u64 lockend = lockstart +
1538 (dirty_pages << PAGE_CACHE_SHIFT) - 1;
1539
1540 set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
1541 lockend, EXTENT_NORESERVE, NULL,
1542 NULL, GFP_NOFS);
1543 only_release_metadata = false;
1544 }
1545
1546 cond_resched();
1547
1548 balance_dirty_pages_ratelimited(inode->i_mapping);
1549 if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1550 btrfs_btree_balance_dirty(root);
1551
1552 pos += copied;
1553 num_written += copied;
1554 }
1555
1556 kfree(pages);
1557
1558 if (release_bytes) {
1559 if (only_release_metadata)
1560 btrfs_delalloc_release_metadata(inode, release_bytes);
1561 else
1562 btrfs_delalloc_release_space(inode, release_bytes);
1563 }
1564
1565 return num_written ? num_written : ret;
1566 }
1567
1568 static ssize_t __btrfs_direct_write(struct kiocb *iocb,
1569 const struct iovec *iov,
1570 unsigned long nr_segs, loff_t pos,
1571 loff_t *ppos, size_t count, size_t ocount)
1572 {
1573 struct file *file = iocb->ki_filp;
1574 struct iov_iter i;
1575 ssize_t written;
1576 ssize_t written_buffered;
1577 loff_t endbyte;
1578 int err;
1579
1580 written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
1581 count, ocount);
1582
1583 if (written < 0 || written == count)
1584 return written;
1585
1586 pos += written;
1587 count -= written;
1588 iov_iter_init(&i, iov, nr_segs, count, written);
1589 written_buffered = __btrfs_buffered_write(file, &i, pos);
1590 if (written_buffered < 0) {
1591 err = written_buffered;
1592 goto out;
1593 }
1594 endbyte = pos + written_buffered - 1;
1595 err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
1596 if (err)
1597 goto out;
1598 written += written_buffered;
1599 *ppos = pos + written_buffered;
1600 invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
1601 endbyte >> PAGE_CACHE_SHIFT);
1602 out:
1603 return written ? written : err;
1604 }
1605
1606 static void update_time_for_write(struct inode *inode)
1607 {
1608 struct timespec now;
1609
1610 if (IS_NOCMTIME(inode))
1611 return;
1612
1613 now = current_fs_time(inode->i_sb);
1614 if (!timespec_equal(&inode->i_mtime, &now))
1615 inode->i_mtime = now;
1616
1617 if (!timespec_equal(&inode->i_ctime, &now))
1618 inode->i_ctime = now;
1619
1620 if (IS_I_VERSION(inode))
1621 inode_inc_iversion(inode);
1622 }
1623
1624 static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
1625 const struct iovec *iov,
1626 unsigned long nr_segs, loff_t pos)
1627 {
1628 struct file *file = iocb->ki_filp;
1629 struct inode *inode = file_inode(file);
1630 struct btrfs_root *root = BTRFS_I(inode)->root;
1631 loff_t *ppos = &iocb->ki_pos;
1632 u64 start_pos;
1633 ssize_t num_written = 0;
1634 ssize_t err = 0;
1635 size_t count, ocount;
1636 bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
1637
1638 mutex_lock(&inode->i_mutex);
1639
1640 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1641 if (err) {
1642 mutex_unlock(&inode->i_mutex);
1643 goto out;
1644 }
1645 count = ocount;
1646
1647 current->backing_dev_info = inode->i_mapping->backing_dev_info;
1648 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1649 if (err) {
1650 mutex_unlock(&inode->i_mutex);
1651 goto out;
1652 }
1653
1654 if (count == 0) {
1655 mutex_unlock(&inode->i_mutex);
1656 goto out;
1657 }
1658
1659 err = file_remove_suid(file);
1660 if (err) {
1661 mutex_unlock(&inode->i_mutex);
1662 goto out;
1663 }
1664
1665 /*
1666 * If BTRFS flips readonly due to some impossible error
1667 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1668 * although we have opened a file as writable, we have
1669 * to stop this write operation to ensure FS consistency.
1670 */
1671 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1672 mutex_unlock(&inode->i_mutex);
1673 err = -EROFS;
1674 goto out;
1675 }
1676
1677 /*
1678 * We reserve space for updating the inode when we reserve space for the
1679 * extent we are going to write, so we will enospc out there. We don't
1680 * need to start yet another transaction to update the inode as we will
1681 * update the inode when we finish writing whatever data we write.
1682 */
1683 update_time_for_write(inode);
1684
1685 start_pos = round_down(pos, root->sectorsize);
1686 if (start_pos > i_size_read(inode)) {
1687 err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
1688 if (err) {
1689 mutex_unlock(&inode->i_mutex);
1690 goto out;
1691 }
1692 }
1693
1694 if (sync)
1695 atomic_inc(&BTRFS_I(inode)->sync_writers);
1696
1697 if (unlikely(file->f_flags & O_DIRECT)) {
1698 num_written = __btrfs_direct_write(iocb, iov, nr_segs,
1699 pos, ppos, count, ocount);
1700 } else {
1701 struct iov_iter i;
1702
1703 iov_iter_init(&i, iov, nr_segs, count, num_written);
1704
1705 num_written = __btrfs_buffered_write(file, &i, pos);
1706 if (num_written > 0)
1707 *ppos = pos + num_written;
1708 }
1709
1710 mutex_unlock(&inode->i_mutex);
1711
1712 /*
1713 * we want to make sure fsync finds this change
1714 * but we haven't joined a transaction running right now.
1715 *
1716 * Later on, someone is sure to update the inode and get the
1717 * real transid recorded.
1718 *
1719 * We set last_trans now to the fs_info generation + 1,
1720 * this will either be one more than the running transaction
1721 * or the generation used for the next transaction if there isn't
1722 * one running right now.
1723 *
1724 * We also have to set last_sub_trans to the current log transid,
1725 * otherwise subsequent syncs to a file that's been synced in this
1726 * transaction will appear to have already occured.
1727 */
1728 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1729 BTRFS_I(inode)->last_sub_trans = root->log_transid;
1730 if (num_written > 0 || num_written == -EIOCBQUEUED) {
1731 err = generic_write_sync(file, pos, num_written);
1732 if (err < 0 && num_written > 0)
1733 num_written = err;
1734 }
1735
1736 if (sync)
1737 atomic_dec(&BTRFS_I(inode)->sync_writers);
1738 out:
1739 current->backing_dev_info = NULL;
1740 return num_written ? num_written : err;
1741 }
1742
1743 int btrfs_release_file(struct inode *inode, struct file *filp)
1744 {
1745 /*
1746 * ordered_data_close is set by settattr when we are about to truncate
1747 * a file from a non-zero size to a zero size. This tries to
1748 * flush down new bytes that may have been written if the
1749 * application were using truncate to replace a file in place.
1750 */
1751 if (test_and_clear_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
1752 &BTRFS_I(inode)->runtime_flags)) {
1753 struct btrfs_trans_handle *trans;
1754 struct btrfs_root *root = BTRFS_I(inode)->root;
1755
1756 /*
1757 * We need to block on a committing transaction to keep us from
1758 * throwing a ordered operation on to the list and causing
1759 * something like sync to deadlock trying to flush out this
1760 * inode.
1761 */
1762 trans = btrfs_start_transaction(root, 0);
1763 if (IS_ERR(trans))
1764 return PTR_ERR(trans);
1765 btrfs_add_ordered_operation(trans, BTRFS_I(inode)->root, inode);
1766 btrfs_end_transaction(trans, root);
1767 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1768 filemap_flush(inode->i_mapping);
1769 }
1770 if (filp->private_data)
1771 btrfs_ioctl_trans_end(filp);
1772 return 0;
1773 }
1774
1775 /*
1776 * fsync call for both files and directories. This logs the inode into
1777 * the tree log instead of forcing full commits whenever possible.
1778 *
1779 * It needs to call filemap_fdatawait so that all ordered extent updates are
1780 * in the metadata btree are up to date for copying to the log.
1781 *
1782 * It drops the inode mutex before doing the tree log commit. This is an
1783 * important optimization for directories because holding the mutex prevents
1784 * new operations on the dir while we write to disk.
1785 */
1786 int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
1787 {
1788 struct dentry *dentry = file->f_path.dentry;
1789 struct inode *inode = dentry->d_inode;
1790 struct btrfs_root *root = BTRFS_I(inode)->root;
1791 int ret = 0;
1792 struct btrfs_trans_handle *trans;
1793 bool full_sync = 0;
1794
1795 trace_btrfs_sync_file(file, datasync);
1796
1797 /*
1798 * We write the dirty pages in the range and wait until they complete
1799 * out of the ->i_mutex. If so, we can flush the dirty pages by
1800 * multi-task, and make the performance up. See
1801 * btrfs_wait_ordered_range for an explanation of the ASYNC check.
1802 */
1803 atomic_inc(&BTRFS_I(inode)->sync_writers);
1804 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
1805 if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1806 &BTRFS_I(inode)->runtime_flags))
1807 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
1808 atomic_dec(&BTRFS_I(inode)->sync_writers);
1809 if (ret)
1810 return ret;
1811
1812 mutex_lock(&inode->i_mutex);
1813
1814 /*
1815 * We flush the dirty pages again to avoid some dirty pages in the
1816 * range being left.
1817 */
1818 atomic_inc(&root->log_batch);
1819 full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1820 &BTRFS_I(inode)->runtime_flags);
1821 if (full_sync)
1822 btrfs_wait_ordered_range(inode, start, end - start + 1);
1823 atomic_inc(&root->log_batch);
1824
1825 /*
1826 * check the transaction that last modified this inode
1827 * and see if its already been committed
1828 */
1829 if (!BTRFS_I(inode)->last_trans) {
1830 mutex_unlock(&inode->i_mutex);
1831 goto out;
1832 }
1833
1834 /*
1835 * if the last transaction that changed this file was before
1836 * the current transaction, we can bail out now without any
1837 * syncing
1838 */
1839 smp_mb();
1840 if (btrfs_inode_in_log(inode, root->fs_info->generation) ||
1841 BTRFS_I(inode)->last_trans <=
1842 root->fs_info->last_trans_committed) {
1843 BTRFS_I(inode)->last_trans = 0;
1844
1845 /*
1846 * We'v had everything committed since the last time we were
1847 * modified so clear this flag in case it was set for whatever
1848 * reason, it's no longer relevant.
1849 */
1850 clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1851 &BTRFS_I(inode)->runtime_flags);
1852 mutex_unlock(&inode->i_mutex);
1853 goto out;
1854 }
1855
1856 /*
1857 * ok we haven't committed the transaction yet, lets do a commit
1858 */
1859 if (file->private_data)
1860 btrfs_ioctl_trans_end(file);
1861
1862 trans = btrfs_start_transaction(root, 0);
1863 if (IS_ERR(trans)) {
1864 ret = PTR_ERR(trans);
1865 mutex_unlock(&inode->i_mutex);
1866 goto out;
1867 }
1868
1869 ret = btrfs_log_dentry_safe(trans, root, dentry);
1870 if (ret < 0) {
1871 mutex_unlock(&inode->i_mutex);
1872 goto out;
1873 }
1874
1875 /* we've logged all the items and now have a consistent
1876 * version of the file in the log. It is possible that
1877 * someone will come in and modify the file, but that's
1878 * fine because the log is consistent on disk, and we
1879 * have references to all of the file's extents
1880 *
1881 * It is possible that someone will come in and log the
1882 * file again, but that will end up using the synchronization
1883 * inside btrfs_sync_log to keep things safe.
1884 */
1885 mutex_unlock(&inode->i_mutex);
1886
1887 if (ret != BTRFS_NO_LOG_SYNC) {
1888 if (ret > 0) {
1889 /*
1890 * If we didn't already wait for ordered extents we need
1891 * to do that now.
1892 */
1893 if (!full_sync)
1894 btrfs_wait_ordered_range(inode, start,
1895 end - start + 1);
1896 ret = btrfs_commit_transaction(trans, root);
1897 } else {
1898 ret = btrfs_sync_log(trans, root);
1899 if (ret == 0) {
1900 ret = btrfs_end_transaction(trans, root);
1901 } else {
1902 if (!full_sync)
1903 btrfs_wait_ordered_range(inode, start,
1904 end -
1905 start + 1);
1906 ret = btrfs_commit_transaction(trans, root);
1907 }
1908 }
1909 } else {
1910 ret = btrfs_end_transaction(trans, root);
1911 }
1912 out:
1913 return ret > 0 ? -EIO : ret;
1914 }
1915
1916 static const struct vm_operations_struct btrfs_file_vm_ops = {
1917 .fault = filemap_fault,
1918 .page_mkwrite = btrfs_page_mkwrite,
1919 .remap_pages = generic_file_remap_pages,
1920 };
1921
1922 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1923 {
1924 struct address_space *mapping = filp->f_mapping;
1925
1926 if (!mapping->a_ops->readpage)
1927 return -ENOEXEC;
1928
1929 file_accessed(filp);
1930 vma->vm_ops = &btrfs_file_vm_ops;
1931
1932 return 0;
1933 }
1934
1935 static int hole_mergeable(struct inode *inode, struct extent_buffer *leaf,
1936 int slot, u64 start, u64 end)
1937 {
1938 struct btrfs_file_extent_item *fi;
1939 struct btrfs_key key;
1940
1941 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
1942 return 0;
1943
1944 btrfs_item_key_to_cpu(leaf, &key, slot);
1945 if (key.objectid != btrfs_ino(inode) ||
1946 key.type != BTRFS_EXTENT_DATA_KEY)
1947 return 0;
1948
1949 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
1950
1951 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
1952 return 0;
1953
1954 if (btrfs_file_extent_disk_bytenr(leaf, fi))
1955 return 0;
1956
1957 if (key.offset == end)
1958 return 1;
1959 if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start)
1960 return 1;
1961 return 0;
1962 }
1963
1964 static int fill_holes(struct btrfs_trans_handle *trans, struct inode *inode,
1965 struct btrfs_path *path, u64 offset, u64 end)
1966 {
1967 struct btrfs_root *root = BTRFS_I(inode)->root;
1968 struct extent_buffer *leaf;
1969 struct btrfs_file_extent_item *fi;
1970 struct extent_map *hole_em;
1971 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1972 struct btrfs_key key;
1973 int ret;
1974
1975 key.objectid = btrfs_ino(inode);
1976 key.type = BTRFS_EXTENT_DATA_KEY;
1977 key.offset = offset;
1978
1979
1980 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1981 if (ret < 0)
1982 return ret;
1983 BUG_ON(!ret);
1984
1985 leaf = path->nodes[0];
1986 if (hole_mergeable(inode, leaf, path->slots[0]-1, offset, end)) {
1987 u64 num_bytes;
1988
1989 path->slots[0]--;
1990 fi = btrfs_item_ptr(leaf, path->slots[0],
1991 struct btrfs_file_extent_item);
1992 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) +
1993 end - offset;
1994 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1995 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
1996 btrfs_set_file_extent_offset(leaf, fi, 0);
1997 btrfs_mark_buffer_dirty(leaf);
1998 goto out;
1999 }
2000
2001 if (hole_mergeable(inode, leaf, path->slots[0]+1, offset, end)) {
2002 u64 num_bytes;
2003
2004 path->slots[0]++;
2005 key.offset = offset;
2006 btrfs_set_item_key_safe(root, path, &key);
2007 fi = btrfs_item_ptr(leaf, path->slots[0],
2008 struct btrfs_file_extent_item);
2009 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
2010 offset;
2011 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2012 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2013 btrfs_set_file_extent_offset(leaf, fi, 0);
2014 btrfs_mark_buffer_dirty(leaf);
2015 goto out;
2016 }
2017 btrfs_release_path(path);
2018
2019 ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
2020 0, 0, end - offset, 0, end - offset,
2021 0, 0, 0);
2022 if (ret)
2023 return ret;
2024
2025 out:
2026 btrfs_release_path(path);
2027
2028 hole_em = alloc_extent_map();
2029 if (!hole_em) {
2030 btrfs_drop_extent_cache(inode, offset, end - 1, 0);
2031 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2032 &BTRFS_I(inode)->runtime_flags);
2033 } else {
2034 hole_em->start = offset;
2035 hole_em->len = end - offset;
2036 hole_em->ram_bytes = hole_em->len;
2037 hole_em->orig_start = offset;
2038
2039 hole_em->block_start = EXTENT_MAP_HOLE;
2040 hole_em->block_len = 0;
2041 hole_em->orig_block_len = 0;
2042 hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
2043 hole_em->compress_type = BTRFS_COMPRESS_NONE;
2044 hole_em->generation = trans->transid;
2045
2046 do {
2047 btrfs_drop_extent_cache(inode, offset, end - 1, 0);
2048 write_lock(&em_tree->lock);
2049 ret = add_extent_mapping(em_tree, hole_em, 1);
2050 write_unlock(&em_tree->lock);
2051 } while (ret == -EEXIST);
2052 free_extent_map(hole_em);
2053 if (ret)
2054 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2055 &BTRFS_I(inode)->runtime_flags);
2056 }
2057
2058 return 0;
2059 }
2060
2061 static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
2062 {
2063 struct btrfs_root *root = BTRFS_I(inode)->root;
2064 struct extent_state *cached_state = NULL;
2065 struct btrfs_path *path;
2066 struct btrfs_block_rsv *rsv;
2067 struct btrfs_trans_handle *trans;
2068 u64 lockstart = round_up(offset, BTRFS_I(inode)->root->sectorsize);
2069 u64 lockend = round_down(offset + len,
2070 BTRFS_I(inode)->root->sectorsize) - 1;
2071 u64 cur_offset = lockstart;
2072 u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
2073 u64 drop_end;
2074 int ret = 0;
2075 int err = 0;
2076 bool same_page = ((offset >> PAGE_CACHE_SHIFT) ==
2077 ((offset + len - 1) >> PAGE_CACHE_SHIFT));
2078
2079 btrfs_wait_ordered_range(inode, offset, len);
2080
2081 mutex_lock(&inode->i_mutex);
2082 /*
2083 * We needn't truncate any page which is beyond the end of the file
2084 * because we are sure there is no data there.
2085 */
2086 /*
2087 * Only do this if we are in the same page and we aren't doing the
2088 * entire page.
2089 */
2090 if (same_page && len < PAGE_CACHE_SIZE) {
2091 if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE))
2092 ret = btrfs_truncate_page(inode, offset, len, 0);
2093 mutex_unlock(&inode->i_mutex);
2094 return ret;
2095 }
2096
2097 /* zero back part of the first page */
2098 if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE)) {
2099 ret = btrfs_truncate_page(inode, offset, 0, 0);
2100 if (ret) {
2101 mutex_unlock(&inode->i_mutex);
2102 return ret;
2103 }
2104 }
2105
2106 /* zero the front end of the last page */
2107 if (offset + len < round_up(inode->i_size, PAGE_CACHE_SIZE)) {
2108 ret = btrfs_truncate_page(inode, offset + len, 0, 1);
2109 if (ret) {
2110 mutex_unlock(&inode->i_mutex);
2111 return ret;
2112 }
2113 }
2114
2115 if (lockend < lockstart) {
2116 mutex_unlock(&inode->i_mutex);
2117 return 0;
2118 }
2119
2120 while (1) {
2121 struct btrfs_ordered_extent *ordered;
2122
2123 truncate_pagecache_range(inode, lockstart, lockend);
2124
2125 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2126 0, &cached_state);
2127 ordered = btrfs_lookup_first_ordered_extent(inode, lockend);
2128
2129 /*
2130 * We need to make sure we have no ordered extents in this range
2131 * and nobody raced in and read a page in this range, if we did
2132 * we need to try again.
2133 */
2134 if ((!ordered ||
2135 (ordered->file_offset + ordered->len < lockstart ||
2136 ordered->file_offset > lockend)) &&
2137 !test_range_bit(&BTRFS_I(inode)->io_tree, lockstart,
2138 lockend, EXTENT_UPTODATE, 0,
2139 cached_state)) {
2140 if (ordered)
2141 btrfs_put_ordered_extent(ordered);
2142 break;
2143 }
2144 if (ordered)
2145 btrfs_put_ordered_extent(ordered);
2146 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
2147 lockend, &cached_state, GFP_NOFS);
2148 btrfs_wait_ordered_range(inode, lockstart,
2149 lockend - lockstart + 1);
2150 }
2151
2152 path = btrfs_alloc_path();
2153 if (!path) {
2154 ret = -ENOMEM;
2155 goto out;
2156 }
2157
2158 rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
2159 if (!rsv) {
2160 ret = -ENOMEM;
2161 goto out_free;
2162 }
2163 rsv->size = btrfs_calc_trunc_metadata_size(root, 1);
2164 rsv->failfast = 1;
2165
2166 /*
2167 * 1 - update the inode
2168 * 1 - removing the extents in the range
2169 * 1 - adding the hole extent
2170 */
2171 trans = btrfs_start_transaction(root, 3);
2172 if (IS_ERR(trans)) {
2173 err = PTR_ERR(trans);
2174 goto out_free;
2175 }
2176
2177 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
2178 min_size);
2179 BUG_ON(ret);
2180 trans->block_rsv = rsv;
2181
2182 while (cur_offset < lockend) {
2183 ret = __btrfs_drop_extents(trans, root, inode, path,
2184 cur_offset, lockend + 1,
2185 &drop_end, 1);
2186 if (ret != -ENOSPC)
2187 break;
2188
2189 trans->block_rsv = &root->fs_info->trans_block_rsv;
2190
2191 ret = fill_holes(trans, inode, path, cur_offset, drop_end);
2192 if (ret) {
2193 err = ret;
2194 break;
2195 }
2196
2197 cur_offset = drop_end;
2198
2199 ret = btrfs_update_inode(trans, root, inode);
2200 if (ret) {
2201 err = ret;
2202 break;
2203 }
2204
2205 btrfs_end_transaction(trans, root);
2206 btrfs_btree_balance_dirty(root);
2207
2208 trans = btrfs_start_transaction(root, 3);
2209 if (IS_ERR(trans)) {
2210 ret = PTR_ERR(trans);
2211 trans = NULL;
2212 break;
2213 }
2214
2215 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
2216 rsv, min_size);
2217 BUG_ON(ret); /* shouldn't happen */
2218 trans->block_rsv = rsv;
2219 }
2220
2221 if (ret) {
2222 err = ret;
2223 goto out_trans;
2224 }
2225
2226 trans->block_rsv = &root->fs_info->trans_block_rsv;
2227 ret = fill_holes(trans, inode, path, cur_offset, drop_end);
2228 if (ret) {
2229 err = ret;
2230 goto out_trans;
2231 }
2232
2233 out_trans:
2234 if (!trans)
2235 goto out_free;
2236
2237 inode_inc_iversion(inode);
2238 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
2239
2240 trans->block_rsv = &root->fs_info->trans_block_rsv;
2241 ret = btrfs_update_inode(trans, root, inode);
2242 btrfs_end_transaction(trans, root);
2243 btrfs_btree_balance_dirty(root);
2244 out_free:
2245 btrfs_free_path(path);
2246 btrfs_free_block_rsv(root, rsv);
2247 out:
2248 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2249 &cached_state, GFP_NOFS);
2250 mutex_unlock(&inode->i_mutex);
2251 if (ret && !err)
2252 err = ret;
2253 return err;
2254 }
2255
2256 static long btrfs_fallocate(struct file *file, int mode,
2257 loff_t offset, loff_t len)
2258 {
2259 struct inode *inode = file_inode(file);
2260 struct extent_state *cached_state = NULL;
2261 struct btrfs_root *root = BTRFS_I(inode)->root;
2262 u64 cur_offset;
2263 u64 last_byte;
2264 u64 alloc_start;
2265 u64 alloc_end;
2266 u64 alloc_hint = 0;
2267 u64 locked_end;
2268 struct extent_map *em;
2269 int blocksize = BTRFS_I(inode)->root->sectorsize;
2270 int ret;
2271
2272 alloc_start = round_down(offset, blocksize);
2273 alloc_end = round_up(offset + len, blocksize);
2274
2275 /* Make sure we aren't being give some crap mode */
2276 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
2277 return -EOPNOTSUPP;
2278
2279 if (mode & FALLOC_FL_PUNCH_HOLE)
2280 return btrfs_punch_hole(inode, offset, len);
2281
2282 /*
2283 * Make sure we have enough space before we do the
2284 * allocation.
2285 */
2286 ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
2287 if (ret)
2288 return ret;
2289 if (root->fs_info->quota_enabled) {
2290 ret = btrfs_qgroup_reserve(root, alloc_end - alloc_start);
2291 if (ret)
2292 goto out_reserve_fail;
2293 }
2294
2295 mutex_lock(&inode->i_mutex);
2296 ret = inode_newsize_ok(inode, alloc_end);
2297 if (ret)
2298 goto out;
2299
2300 if (alloc_start > inode->i_size) {
2301 ret = btrfs_cont_expand(inode, i_size_read(inode),
2302 alloc_start);
2303 if (ret)
2304 goto out;
2305 } else {
2306 /*
2307 * If we are fallocating from the end of the file onward we
2308 * need to zero out the end of the page if i_size lands in the
2309 * middle of a page.
2310 */
2311 ret = btrfs_truncate_page(inode, inode->i_size, 0, 0);
2312 if (ret)
2313 goto out;
2314 }
2315
2316 /*
2317 * wait for ordered IO before we have any locks. We'll loop again
2318 * below with the locks held.
2319 */
2320 btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
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 btrfs_wait_ordered_range(inode, alloc_start,
2345 alloc_end - alloc_start);
2346 } else {
2347 if (ordered)
2348 btrfs_put_ordered_extent(ordered);
2349 break;
2350 }
2351 }
2352
2353 cur_offset = alloc_start;
2354 while (1) {
2355 u64 actual_end;
2356
2357 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
2358 alloc_end - cur_offset, 0);
2359 if (IS_ERR_OR_NULL(em)) {
2360 if (!em)
2361 ret = -ENOMEM;
2362 else
2363 ret = PTR_ERR(em);
2364 break;
2365 }
2366 last_byte = min(extent_map_end(em), alloc_end);
2367 actual_end = min_t(u64, extent_map_end(em), offset + len);
2368 last_byte = ALIGN(last_byte, blocksize);
2369
2370 if (em->block_start == EXTENT_MAP_HOLE ||
2371 (cur_offset >= inode->i_size &&
2372 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
2373 ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
2374 last_byte - cur_offset,
2375 1 << inode->i_blkbits,
2376 offset + len,
2377 &alloc_hint);
2378
2379 if (ret < 0) {
2380 free_extent_map(em);
2381 break;
2382 }
2383 } else if (actual_end > inode->i_size &&
2384 !(mode & FALLOC_FL_KEEP_SIZE)) {
2385 /*
2386 * We didn't need to allocate any more space, but we
2387 * still extended the size of the file so we need to
2388 * update i_size.
2389 */
2390 inode->i_ctime = CURRENT_TIME;
2391 i_size_write(inode, actual_end);
2392 btrfs_ordered_update_i_size(inode, actual_end, NULL);
2393 }
2394 free_extent_map(em);
2395
2396 cur_offset = last_byte;
2397 if (cur_offset >= alloc_end) {
2398 ret = 0;
2399 break;
2400 }
2401 }
2402 unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
2403 &cached_state, GFP_NOFS);
2404 out:
2405 mutex_unlock(&inode->i_mutex);
2406 if (root->fs_info->quota_enabled)
2407 btrfs_qgroup_free(root, alloc_end - alloc_start);
2408 out_reserve_fail:
2409 /* Let go of our reservation. */
2410 btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
2411 return ret;
2412 }
2413
2414 static int find_desired_extent(struct inode *inode, loff_t *offset, int whence)
2415 {
2416 struct btrfs_root *root = BTRFS_I(inode)->root;
2417 struct extent_map *em;
2418 struct extent_state *cached_state = NULL;
2419 u64 lockstart = *offset;
2420 u64 lockend = i_size_read(inode);
2421 u64 start = *offset;
2422 u64 orig_start = *offset;
2423 u64 len = i_size_read(inode);
2424 u64 last_end = 0;
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 /*
2442 * Delalloc is such a pain. If we have a hole and we have pending
2443 * delalloc for a portion of the hole we will get back a hole that
2444 * exists for the entire range since it hasn't been actually written
2445 * yet. So to take care of this case we need to look for an extent just
2446 * before the position we want in case there is outstanding delalloc
2447 * going on here.
2448 */
2449 if (whence == SEEK_HOLE && start != 0) {
2450 if (start <= root->sectorsize)
2451 em = btrfs_get_extent_fiemap(inode, NULL, 0, 0,
2452 root->sectorsize, 0);
2453 else
2454 em = btrfs_get_extent_fiemap(inode, NULL, 0,
2455 start - root->sectorsize,
2456 root->sectorsize, 0);
2457 if (IS_ERR(em)) {
2458 ret = PTR_ERR(em);
2459 goto out;
2460 }
2461 last_end = em->start + em->len;
2462 if (em->block_start == EXTENT_MAP_DELALLOC)
2463 last_end = min_t(u64, last_end, inode->i_size);
2464 free_extent_map(em);
2465 }
2466
2467 while (1) {
2468 em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
2469 if (IS_ERR(em)) {
2470 ret = PTR_ERR(em);
2471 break;
2472 }
2473
2474 if (em->block_start == EXTENT_MAP_HOLE) {
2475 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
2476 if (last_end <= orig_start) {
2477 free_extent_map(em);
2478 ret = -ENXIO;
2479 break;
2480 }
2481 }
2482
2483 if (whence == SEEK_HOLE) {
2484 *offset = start;
2485 free_extent_map(em);
2486 break;
2487 }
2488 } else {
2489 if (whence == SEEK_DATA) {
2490 if (em->block_start == EXTENT_MAP_DELALLOC) {
2491 if (start >= inode->i_size) {
2492 free_extent_map(em);
2493 ret = -ENXIO;
2494 break;
2495 }
2496 }
2497
2498 if (!test_bit(EXTENT_FLAG_PREALLOC,
2499 &em->flags)) {
2500 *offset = start;
2501 free_extent_map(em);
2502 break;
2503 }
2504 }
2505 }
2506
2507 start = em->start + em->len;
2508 last_end = em->start + em->len;
2509
2510 if (em->block_start == EXTENT_MAP_DELALLOC)
2511 last_end = min_t(u64, last_end, inode->i_size);
2512
2513 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
2514 free_extent_map(em);
2515 ret = -ENXIO;
2516 break;
2517 }
2518 free_extent_map(em);
2519 cond_resched();
2520 }
2521 if (!ret)
2522 *offset = min(*offset, inode->i_size);
2523 out:
2524 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2525 &cached_state, GFP_NOFS);
2526 return ret;
2527 }
2528
2529 static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
2530 {
2531 struct inode *inode = file->f_mapping->host;
2532 int ret;
2533
2534 mutex_lock(&inode->i_mutex);
2535 switch (whence) {
2536 case SEEK_END:
2537 case SEEK_CUR:
2538 offset = generic_file_llseek(file, offset, whence);
2539 goto out;
2540 case SEEK_DATA:
2541 case SEEK_HOLE:
2542 if (offset >= i_size_read(inode)) {
2543 mutex_unlock(&inode->i_mutex);
2544 return -ENXIO;
2545 }
2546
2547 ret = find_desired_extent(inode, &offset, whence);
2548 if (ret) {
2549 mutex_unlock(&inode->i_mutex);
2550 return ret;
2551 }
2552 }
2553
2554 offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
2555 out:
2556 mutex_unlock(&inode->i_mutex);
2557 return offset;
2558 }
2559
2560 const struct file_operations btrfs_file_operations = {
2561 .llseek = btrfs_file_llseek,
2562 .read = do_sync_read,
2563 .write = do_sync_write,
2564 .aio_read = generic_file_aio_read,
2565 .splice_read = generic_file_splice_read,
2566 .aio_write = btrfs_file_aio_write,
2567 .mmap = btrfs_file_mmap,
2568 .open = generic_file_open,
2569 .release = btrfs_release_file,
2570 .fsync = btrfs_sync_file,
2571 .fallocate = btrfs_fallocate,
2572 .unlocked_ioctl = btrfs_ioctl,
2573 #ifdef CONFIG_COMPAT
2574 .compat_ioctl = btrfs_ioctl,
2575 #endif
2576 };
2577
2578 void btrfs_auto_defrag_exit(void)
2579 {
2580 if (btrfs_inode_defrag_cachep)
2581 kmem_cache_destroy(btrfs_inode_defrag_cachep);
2582 }
2583
2584 int btrfs_auto_defrag_init(void)
2585 {
2586 btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
2587 sizeof(struct inode_defrag), 0,
2588 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
2589 NULL);
2590 if (!btrfs_inode_defrag_cachep)
2591 return -ENOMEM;
2592
2593 return 0;
2594 }
Linux with added FPC-III support