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1/*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/fs.h>
20#include <linux/pagemap.h>
21#include <linux/highmem.h>
22#include <linux/time.h>
23#include <linux/init.h>
24#include <linux/string.h>
25#include <linux/backing-dev.h>
26#include <linux/mpage.h>
27#include <linux/falloc.h>
28#include <linux/swap.h>
29#include <linux/writeback.h>
30#include <linux/compat.h>
31#include <linux/slab.h>
32#include <linux/btrfs.h>
33#include <linux/uio.h>
34#include "ctree.h"
35#include "disk-io.h"
36#include "transaction.h"
37#include "btrfs_inode.h"
38#include "print-tree.h"
39#include "tree-log.h"
40#include "locking.h"
41#include "volumes.h"
42#include "qgroup.h"
43#include "compression.h"
44
45static 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 */
51struct 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
71static 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 */
95static int __btrfs_add_inode_defrag(struct inode *inode,
96 struct inode_defrag *defrag)
97{
98 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
99 struct inode_defrag *entry;
100 struct rb_node **p;
101 struct rb_node *parent = NULL;
102 int ret;
103
104 p = &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, &fs_info->defrag_inodes);
129 return 0;
130}
131
132static inline int __need_auto_defrag(struct btrfs_fs_info *fs_info)
133{
134 if (!btrfs_test_opt(fs_info, AUTO_DEFRAG))
135 return 0;
136
137 if (btrfs_fs_closing(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 */
147int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
148 struct inode *inode)
149{
150 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
151 struct btrfs_root *root = BTRFS_I(inode)->root;
152 struct inode_defrag *defrag;
153 u64 transid;
154 int ret;
155
156 if (!__need_auto_defrag(fs_info))
157 return 0;
158
159 if (test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags))
160 return 0;
161
162 if (trans)
163 transid = trans->transid;
164 else
165 transid = BTRFS_I(inode)->root->last_trans;
166
167 defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS);
168 if (!defrag)
169 return -ENOMEM;
170
171 defrag->ino = btrfs_ino(inode);
172 defrag->transid = transid;
173 defrag->root = root->root_key.objectid;
174
175 spin_lock(&fs_info->defrag_inodes_lock);
176 if (!test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags)) {
177 /*
178 * If we set IN_DEFRAG flag and evict the inode from memory,
179 * and then re-read this inode, this new inode doesn't have
180 * IN_DEFRAG flag. At the case, we may find the existed defrag.
181 */
182 ret = __btrfs_add_inode_defrag(inode, defrag);
183 if (ret)
184 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
185 } else {
186 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
187 }
188 spin_unlock(&fs_info->defrag_inodes_lock);
189 return 0;
190}
191
192/*
193 * Requeue the defrag object. If there is a defrag object that points to
194 * the same inode in the tree, we will merge them together (by
195 * __btrfs_add_inode_defrag()) and free the one that we want to requeue.
196 */
197static void btrfs_requeue_inode_defrag(struct inode *inode,
198 struct inode_defrag *defrag)
199{
200 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
201 int ret;
202
203 if (!__need_auto_defrag(fs_info))
204 goto out;
205
206 /*
207 * Here we don't check the IN_DEFRAG flag, because we need merge
208 * them together.
209 */
210 spin_lock(&fs_info->defrag_inodes_lock);
211 ret = __btrfs_add_inode_defrag(inode, defrag);
212 spin_unlock(&fs_info->defrag_inodes_lock);
213 if (ret)
214 goto out;
215 return;
216out:
217 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
218}
219
220/*
221 * pick the defragable inode that we want, if it doesn't exist, we will get
222 * the next one.
223 */
224static struct inode_defrag *
225btrfs_pick_defrag_inode(struct btrfs_fs_info *fs_info, u64 root, u64 ino)
226{
227 struct inode_defrag *entry = NULL;
228 struct inode_defrag tmp;
229 struct rb_node *p;
230 struct rb_node *parent = NULL;
231 int ret;
232
233 tmp.ino = ino;
234 tmp.root = root;
235
236 spin_lock(&fs_info->defrag_inodes_lock);
237 p = fs_info->defrag_inodes.rb_node;
238 while (p) {
239 parent = p;
240 entry = rb_entry(parent, struct inode_defrag, rb_node);
241
242 ret = __compare_inode_defrag(&tmp, entry);
243 if (ret < 0)
244 p = parent->rb_left;
245 else if (ret > 0)
246 p = parent->rb_right;
247 else
248 goto out;
249 }
250
251 if (parent && __compare_inode_defrag(&tmp, entry) > 0) {
252 parent = rb_next(parent);
253 if (parent)
254 entry = rb_entry(parent, struct inode_defrag, rb_node);
255 else
256 entry = NULL;
257 }
258out:
259 if (entry)
260 rb_erase(parent, &fs_info->defrag_inodes);
261 spin_unlock(&fs_info->defrag_inodes_lock);
262 return entry;
263}
264
265void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info)
266{
267 struct inode_defrag *defrag;
268 struct rb_node *node;
269
270 spin_lock(&fs_info->defrag_inodes_lock);
271 node = rb_first(&fs_info->defrag_inodes);
272 while (node) {
273 rb_erase(node, &fs_info->defrag_inodes);
274 defrag = rb_entry(node, struct inode_defrag, rb_node);
275 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
276
277 cond_resched_lock(&fs_info->defrag_inodes_lock);
278
279 node = rb_first(&fs_info->defrag_inodes);
280 }
281 spin_unlock(&fs_info->defrag_inodes_lock);
282}
283
284#define BTRFS_DEFRAG_BATCH 1024
285
286static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
287 struct inode_defrag *defrag)
288{
289 struct btrfs_root *inode_root;
290 struct inode *inode;
291 struct btrfs_key key;
292 struct btrfs_ioctl_defrag_range_args range;
293 int num_defrag;
294 int index;
295 int ret;
296
297 /* get the inode */
298 key.objectid = defrag->root;
299 key.type = BTRFS_ROOT_ITEM_KEY;
300 key.offset = (u64)-1;
301
302 index = srcu_read_lock(&fs_info->subvol_srcu);
303
304 inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
305 if (IS_ERR(inode_root)) {
306 ret = PTR_ERR(inode_root);
307 goto cleanup;
308 }
309
310 key.objectid = defrag->ino;
311 key.type = BTRFS_INODE_ITEM_KEY;
312 key.offset = 0;
313 inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
314 if (IS_ERR(inode)) {
315 ret = PTR_ERR(inode);
316 goto cleanup;
317 }
318 srcu_read_unlock(&fs_info->subvol_srcu, index);
319
320 /* do a chunk of defrag */
321 clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
322 memset(&range, 0, sizeof(range));
323 range.len = (u64)-1;
324 range.start = defrag->last_offset;
325
326 sb_start_write(fs_info->sb);
327 num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
328 BTRFS_DEFRAG_BATCH);
329 sb_end_write(fs_info->sb);
330 /*
331 * if we filled the whole defrag batch, there
332 * must be more work to do. Queue this defrag
333 * again
334 */
335 if (num_defrag == BTRFS_DEFRAG_BATCH) {
336 defrag->last_offset = range.start;
337 btrfs_requeue_inode_defrag(inode, defrag);
338 } else if (defrag->last_offset && !defrag->cycled) {
339 /*
340 * we didn't fill our defrag batch, but
341 * we didn't start at zero. Make sure we loop
342 * around to the start of the file.
343 */
344 defrag->last_offset = 0;
345 defrag->cycled = 1;
346 btrfs_requeue_inode_defrag(inode, defrag);
347 } else {
348 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
349 }
350
351 iput(inode);
352 return 0;
353cleanup:
354 srcu_read_unlock(&fs_info->subvol_srcu, index);
355 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
356 return ret;
357}
358
359/*
360 * run through the list of inodes in the FS that need
361 * defragging
362 */
363int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
364{
365 struct inode_defrag *defrag;
366 u64 first_ino = 0;
367 u64 root_objectid = 0;
368
369 atomic_inc(&fs_info->defrag_running);
370 while (1) {
371 /* Pause the auto defragger. */
372 if (test_bit(BTRFS_FS_STATE_REMOUNTING,
373 &fs_info->fs_state))
374 break;
375
376 if (!__need_auto_defrag(fs_info))
377 break;
378
379 /* find an inode to defrag */
380 defrag = btrfs_pick_defrag_inode(fs_info, root_objectid,
381 first_ino);
382 if (!defrag) {
383 if (root_objectid || first_ino) {
384 root_objectid = 0;
385 first_ino = 0;
386 continue;
387 } else {
388 break;
389 }
390 }
391
392 first_ino = defrag->ino + 1;
393 root_objectid = defrag->root;
394
395 __btrfs_run_defrag_inode(fs_info, defrag);
396 }
397 atomic_dec(&fs_info->defrag_running);
398
399 /*
400 * during unmount, we use the transaction_wait queue to
401 * wait for the defragger to stop
402 */
403 wake_up(&fs_info->transaction_wait);
404 return 0;
405}
406
407/* simple helper to fault in pages and copy. This should go away
408 * and be replaced with calls into generic code.
409 */
410static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes,
411 struct page **prepared_pages,
412 struct iov_iter *i)
413{
414 size_t copied = 0;
415 size_t total_copied = 0;
416 int pg = 0;
417 int offset = pos & (PAGE_SIZE - 1);
418
419 while (write_bytes > 0) {
420 size_t count = min_t(size_t,
421 PAGE_SIZE - offset, write_bytes);
422 struct page *page = prepared_pages[pg];
423 /*
424 * Copy data from userspace to the current page
425 */
426 copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
427
428 /* Flush processor's dcache for this page */
429 flush_dcache_page(page);
430
431 /*
432 * if we get a partial write, we can end up with
433 * partially up to date pages. These add
434 * a lot of complexity, so make sure they don't
435 * happen by forcing this copy to be retried.
436 *
437 * The rest of the btrfs_file_write code will fall
438 * back to page at a time copies after we return 0.
439 */
440 if (!PageUptodate(page) && copied < count)
441 copied = 0;
442
443 iov_iter_advance(i, copied);
444 write_bytes -= copied;
445 total_copied += copied;
446
447 /* Return to btrfs_file_write_iter to fault page */
448 if (unlikely(copied == 0))
449 break;
450
451 if (copied < PAGE_SIZE - offset) {
452 offset += copied;
453 } else {
454 pg++;
455 offset = 0;
456 }
457 }
458 return total_copied;
459}
460
461/*
462 * unlocks pages after btrfs_file_write is done with them
463 */
464static void btrfs_drop_pages(struct page **pages, size_t num_pages)
465{
466 size_t i;
467 for (i = 0; i < num_pages; i++) {
468 /* page checked is some magic around finding pages that
469 * have been modified without going through btrfs_set_page_dirty
470 * clear it here. There should be no need to mark the pages
471 * accessed as prepare_pages should have marked them accessed
472 * in prepare_pages via find_or_create_page()
473 */
474 ClearPageChecked(pages[i]);
475 unlock_page(pages[i]);
476 put_page(pages[i]);
477 }
478}
479
480/*
481 * after copy_from_user, pages need to be dirtied and we need to make
482 * sure holes are created between the current EOF and the start of
483 * any next extents (if required).
484 *
485 * this also makes the decision about creating an inline extent vs
486 * doing real data extents, marking pages dirty and delalloc as required.
487 */
488int btrfs_dirty_pages(struct inode *inode, struct page **pages,
489 size_t num_pages, loff_t pos, size_t write_bytes,
490 struct extent_state **cached)
491{
492 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
493 int err = 0;
494 int i;
495 u64 num_bytes;
496 u64 start_pos;
497 u64 end_of_last_block;
498 u64 end_pos = pos + write_bytes;
499 loff_t isize = i_size_read(inode);
500
501 start_pos = pos & ~((u64) fs_info->sectorsize - 1);
502 num_bytes = round_up(write_bytes + pos - start_pos,
503 fs_info->sectorsize);
504
505 end_of_last_block = start_pos + num_bytes - 1;
506 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
507 cached, 0);
508 if (err)
509 return err;
510
511 for (i = 0; i < num_pages; i++) {
512 struct page *p = pages[i];
513 SetPageUptodate(p);
514 ClearPageChecked(p);
515 set_page_dirty(p);
516 }
517
518 /*
519 * we've only changed i_size in ram, and we haven't updated
520 * the disk i_size. There is no need to log the inode
521 * at this time.
522 */
523 if (end_pos > isize)
524 i_size_write(inode, end_pos);
525 return 0;
526}
527
528/*
529 * this drops all the extents in the cache that intersect the range
530 * [start, end]. Existing extents are split as required.
531 */
532void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
533 int skip_pinned)
534{
535 struct extent_map *em;
536 struct extent_map *split = NULL;
537 struct extent_map *split2 = NULL;
538 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
539 u64 len = end - start + 1;
540 u64 gen;
541 int ret;
542 int testend = 1;
543 unsigned long flags;
544 int compressed = 0;
545 bool modified;
546
547 WARN_ON(end < start);
548 if (end == (u64)-1) {
549 len = (u64)-1;
550 testend = 0;
551 }
552 while (1) {
553 int no_splits = 0;
554
555 modified = false;
556 if (!split)
557 split = alloc_extent_map();
558 if (!split2)
559 split2 = alloc_extent_map();
560 if (!split || !split2)
561 no_splits = 1;
562
563 write_lock(&em_tree->lock);
564 em = lookup_extent_mapping(em_tree, start, len);
565 if (!em) {
566 write_unlock(&em_tree->lock);
567 break;
568 }
569 flags = em->flags;
570 gen = em->generation;
571 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
572 if (testend && em->start + em->len >= start + len) {
573 free_extent_map(em);
574 write_unlock(&em_tree->lock);
575 break;
576 }
577 start = em->start + em->len;
578 if (testend)
579 len = start + len - (em->start + em->len);
580 free_extent_map(em);
581 write_unlock(&em_tree->lock);
582 continue;
583 }
584 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
585 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
586 clear_bit(EXTENT_FLAG_LOGGING, &flags);
587 modified = !list_empty(&em->list);
588 if (no_splits)
589 goto next;
590
591 if (em->start < start) {
592 split->start = em->start;
593 split->len = start - em->start;
594
595 if (em->block_start < EXTENT_MAP_LAST_BYTE) {
596 split->orig_start = em->orig_start;
597 split->block_start = em->block_start;
598
599 if (compressed)
600 split->block_len = em->block_len;
601 else
602 split->block_len = split->len;
603 split->orig_block_len = max(split->block_len,
604 em->orig_block_len);
605 split->ram_bytes = em->ram_bytes;
606 } else {
607 split->orig_start = split->start;
608 split->block_len = 0;
609 split->block_start = em->block_start;
610 split->orig_block_len = 0;
611 split->ram_bytes = split->len;
612 }
613
614 split->generation = gen;
615 split->bdev = em->bdev;
616 split->flags = flags;
617 split->compress_type = em->compress_type;
618 replace_extent_mapping(em_tree, em, split, modified);
619 free_extent_map(split);
620 split = split2;
621 split2 = NULL;
622 }
623 if (testend && em->start + em->len > start + len) {
624 u64 diff = start + len - em->start;
625
626 split->start = start + len;
627 split->len = em->start + em->len - (start + len);
628 split->bdev = em->bdev;
629 split->flags = flags;
630 split->compress_type = em->compress_type;
631 split->generation = gen;
632
633 if (em->block_start < EXTENT_MAP_LAST_BYTE) {
634 split->orig_block_len = max(em->block_len,
635 em->orig_block_len);
636
637 split->ram_bytes = em->ram_bytes;
638 if (compressed) {
639 split->block_len = em->block_len;
640 split->block_start = em->block_start;
641 split->orig_start = em->orig_start;
642 } else {
643 split->block_len = split->len;
644 split->block_start = em->block_start
645 + diff;
646 split->orig_start = em->orig_start;
647 }
648 } else {
649 split->ram_bytes = split->len;
650 split->orig_start = split->start;
651 split->block_len = 0;
652 split->block_start = em->block_start;
653 split->orig_block_len = 0;
654 }
655
656 if (extent_map_in_tree(em)) {
657 replace_extent_mapping(em_tree, em, split,
658 modified);
659 } else {
660 ret = add_extent_mapping(em_tree, split,
661 modified);
662 ASSERT(ret == 0); /* Logic error */
663 }
664 free_extent_map(split);
665 split = NULL;
666 }
667next:
668 if (extent_map_in_tree(em))
669 remove_extent_mapping(em_tree, em);
670 write_unlock(&em_tree->lock);
671
672 /* once for us */
673 free_extent_map(em);
674 /* once for the tree*/
675 free_extent_map(em);
676 }
677 if (split)
678 free_extent_map(split);
679 if (split2)
680 free_extent_map(split2);
681}
682
683/*
684 * this is very complex, but the basic idea is to drop all extents
685 * in the range start - end. hint_block is filled in with a block number
686 * that would be a good hint to the block allocator for this file.
687 *
688 * If an extent intersects the range but is not entirely inside the range
689 * it is either truncated or split. Anything entirely inside the range
690 * is deleted from the tree.
691 */
692int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
693 struct btrfs_root *root, struct inode *inode,
694 struct btrfs_path *path, u64 start, u64 end,
695 u64 *drop_end, int drop_cache,
696 int replace_extent,
697 u32 extent_item_size,
698 int *key_inserted)
699{
700 struct btrfs_fs_info *fs_info = root->fs_info;
701 struct extent_buffer *leaf;
702 struct btrfs_file_extent_item *fi;
703 struct btrfs_key key;
704 struct btrfs_key new_key;
705 u64 ino = btrfs_ino(inode);
706 u64 search_start = start;
707 u64 disk_bytenr = 0;
708 u64 num_bytes = 0;
709 u64 extent_offset = 0;
710 u64 extent_end = 0;
711 u64 last_end = start;
712 int del_nr = 0;
713 int del_slot = 0;
714 int extent_type;
715 int recow;
716 int ret;
717 int modify_tree = -1;
718 int update_refs;
719 int found = 0;
720 int leafs_visited = 0;
721
722 if (drop_cache)
723 btrfs_drop_extent_cache(inode, start, end - 1, 0);
724
725 if (start >= BTRFS_I(inode)->disk_i_size && !replace_extent)
726 modify_tree = 0;
727
728 update_refs = (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
729 root == fs_info->tree_root);
730 while (1) {
731 recow = 0;
732 ret = btrfs_lookup_file_extent(trans, root, path, ino,
733 search_start, modify_tree);
734 if (ret < 0)
735 break;
736 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
737 leaf = path->nodes[0];
738 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
739 if (key.objectid == ino &&
740 key.type == BTRFS_EXTENT_DATA_KEY)
741 path->slots[0]--;
742 }
743 ret = 0;
744 leafs_visited++;
745next_slot:
746 leaf = path->nodes[0];
747 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
748 BUG_ON(del_nr > 0);
749 ret = btrfs_next_leaf(root, path);
750 if (ret < 0)
751 break;
752 if (ret > 0) {
753 ret = 0;
754 break;
755 }
756 leafs_visited++;
757 leaf = path->nodes[0];
758 recow = 1;
759 }
760
761 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
762
763 if (key.objectid > ino)
764 break;
765 if (WARN_ON_ONCE(key.objectid < ino) ||
766 key.type < BTRFS_EXTENT_DATA_KEY) {
767 ASSERT(del_nr == 0);
768 path->slots[0]++;
769 goto next_slot;
770 }
771 if (key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
772 break;
773
774 fi = btrfs_item_ptr(leaf, path->slots[0],
775 struct btrfs_file_extent_item);
776 extent_type = btrfs_file_extent_type(leaf, fi);
777
778 if (extent_type == BTRFS_FILE_EXTENT_REG ||
779 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
780 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
781 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
782 extent_offset = btrfs_file_extent_offset(leaf, fi);
783 extent_end = key.offset +
784 btrfs_file_extent_num_bytes(leaf, fi);
785 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
786 extent_end = key.offset +
787 btrfs_file_extent_inline_len(leaf,
788 path->slots[0], fi);
789 } else {
790 /* can't happen */
791 BUG();
792 }
793
794 /*
795 * Don't skip extent items representing 0 byte lengths. They
796 * used to be created (bug) if while punching holes we hit
797 * -ENOSPC condition. So if we find one here, just ensure we
798 * delete it, otherwise we would insert a new file extent item
799 * with the same key (offset) as that 0 bytes length file
800 * extent item in the call to setup_items_for_insert() later
801 * in this function.
802 */
803 if (extent_end == key.offset && extent_end >= search_start) {
804 last_end = extent_end;
805 goto delete_extent_item;
806 }
807
808 if (extent_end <= search_start) {
809 path->slots[0]++;
810 goto next_slot;
811 }
812
813 found = 1;
814 search_start = max(key.offset, start);
815 if (recow || !modify_tree) {
816 modify_tree = -1;
817 btrfs_release_path(path);
818 continue;
819 }
820
821 /*
822 * | - range to drop - |
823 * | -------- extent -------- |
824 */
825 if (start > key.offset && end < extent_end) {
826 BUG_ON(del_nr > 0);
827 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
828 ret = -EOPNOTSUPP;
829 break;
830 }
831
832 memcpy(&new_key, &key, sizeof(new_key));
833 new_key.offset = start;
834 ret = btrfs_duplicate_item(trans, root, path,
835 &new_key);
836 if (ret == -EAGAIN) {
837 btrfs_release_path(path);
838 continue;
839 }
840 if (ret < 0)
841 break;
842
843 leaf = path->nodes[0];
844 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
845 struct btrfs_file_extent_item);
846 btrfs_set_file_extent_num_bytes(leaf, fi,
847 start - key.offset);
848
849 fi = btrfs_item_ptr(leaf, path->slots[0],
850 struct btrfs_file_extent_item);
851
852 extent_offset += start - key.offset;
853 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
854 btrfs_set_file_extent_num_bytes(leaf, fi,
855 extent_end - start);
856 btrfs_mark_buffer_dirty(leaf);
857
858 if (update_refs && disk_bytenr > 0) {
859 ret = btrfs_inc_extent_ref(trans, fs_info,
860 disk_bytenr, num_bytes, 0,
861 root->root_key.objectid,
862 new_key.objectid,
863 start - extent_offset);
864 BUG_ON(ret); /* -ENOMEM */
865 }
866 key.offset = start;
867 }
868 /*
869 * From here on out we will have actually dropped something, so
870 * last_end can be updated.
871 */
872 last_end = extent_end;
873
874 /*
875 * | ---- range to drop ----- |
876 * | -------- extent -------- |
877 */
878 if (start <= key.offset && end < extent_end) {
879 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
880 ret = -EOPNOTSUPP;
881 break;
882 }
883
884 memcpy(&new_key, &key, sizeof(new_key));
885 new_key.offset = end;
886 btrfs_set_item_key_safe(fs_info, path, &new_key);
887
888 extent_offset += end - key.offset;
889 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
890 btrfs_set_file_extent_num_bytes(leaf, fi,
891 extent_end - end);
892 btrfs_mark_buffer_dirty(leaf);
893 if (update_refs && disk_bytenr > 0)
894 inode_sub_bytes(inode, end - key.offset);
895 break;
896 }
897
898 search_start = extent_end;
899 /*
900 * | ---- range to drop ----- |
901 * | -------- extent -------- |
902 */
903 if (start > key.offset && end >= extent_end) {
904 BUG_ON(del_nr > 0);
905 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
906 ret = -EOPNOTSUPP;
907 break;
908 }
909
910 btrfs_set_file_extent_num_bytes(leaf, fi,
911 start - key.offset);
912 btrfs_mark_buffer_dirty(leaf);
913 if (update_refs && disk_bytenr > 0)
914 inode_sub_bytes(inode, extent_end - start);
915 if (end == extent_end)
916 break;
917
918 path->slots[0]++;
919 goto next_slot;
920 }
921
922 /*
923 * | ---- range to drop ----- |
924 * | ------ extent ------ |
925 */
926 if (start <= key.offset && end >= extent_end) {
927delete_extent_item:
928 if (del_nr == 0) {
929 del_slot = path->slots[0];
930 del_nr = 1;
931 } else {
932 BUG_ON(del_slot + del_nr != path->slots[0]);
933 del_nr++;
934 }
935
936 if (update_refs &&
937 extent_type == BTRFS_FILE_EXTENT_INLINE) {
938 inode_sub_bytes(inode,
939 extent_end - key.offset);
940 extent_end = ALIGN(extent_end,
941 fs_info->sectorsize);
942 } else if (update_refs && disk_bytenr > 0) {
943 ret = btrfs_free_extent(trans, fs_info,
944 disk_bytenr, num_bytes, 0,
945 root->root_key.objectid,
946 key.objectid, key.offset -
947 extent_offset);
948 BUG_ON(ret); /* -ENOMEM */
949 inode_sub_bytes(inode,
950 extent_end - key.offset);
951 }
952
953 if (end == extent_end)
954 break;
955
956 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
957 path->slots[0]++;
958 goto next_slot;
959 }
960
961 ret = btrfs_del_items(trans, root, path, del_slot,
962 del_nr);
963 if (ret) {
964 btrfs_abort_transaction(trans, ret);
965 break;
966 }
967
968 del_nr = 0;
969 del_slot = 0;
970
971 btrfs_release_path(path);
972 continue;
973 }
974
975 BUG_ON(1);
976 }
977
978 if (!ret && del_nr > 0) {
979 /*
980 * Set path->slots[0] to first slot, so that after the delete
981 * if items are move off from our leaf to its immediate left or
982 * right neighbor leafs, we end up with a correct and adjusted
983 * path->slots[0] for our insertion (if replace_extent != 0).
984 */
985 path->slots[0] = del_slot;
986 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
987 if (ret)
988 btrfs_abort_transaction(trans, ret);
989 }
990
991 leaf = path->nodes[0];
992 /*
993 * If btrfs_del_items() was called, it might have deleted a leaf, in
994 * which case it unlocked our path, so check path->locks[0] matches a
995 * write lock.
996 */
997 if (!ret && replace_extent && leafs_visited == 1 &&
998 (path->locks[0] == BTRFS_WRITE_LOCK_BLOCKING ||
999 path->locks[0] == BTRFS_WRITE_LOCK) &&
1000 btrfs_leaf_free_space(fs_info, leaf) >=
1001 sizeof(struct btrfs_item) + extent_item_size) {
1002
1003 key.objectid = ino;
1004 key.type = BTRFS_EXTENT_DATA_KEY;
1005 key.offset = start;
1006 if (!del_nr && path->slots[0] < btrfs_header_nritems(leaf)) {
1007 struct btrfs_key slot_key;
1008
1009 btrfs_item_key_to_cpu(leaf, &slot_key, path->slots[0]);
1010 if (btrfs_comp_cpu_keys(&key, &slot_key) > 0)
1011 path->slots[0]++;
1012 }
1013 setup_items_for_insert(root, path, &key,
1014 &extent_item_size,
1015 extent_item_size,
1016 sizeof(struct btrfs_item) +
1017 extent_item_size, 1);
1018 *key_inserted = 1;
1019 }
1020
1021 if (!replace_extent || !(*key_inserted))
1022 btrfs_release_path(path);
1023 if (drop_end)
1024 *drop_end = found ? min(end, last_end) : end;
1025 return ret;
1026}
1027
1028int btrfs_drop_extents(struct btrfs_trans_handle *trans,
1029 struct btrfs_root *root, struct inode *inode, u64 start,
1030 u64 end, int drop_cache)
1031{
1032 struct btrfs_path *path;
1033 int ret;
1034
1035 path = btrfs_alloc_path();
1036 if (!path)
1037 return -ENOMEM;
1038 ret = __btrfs_drop_extents(trans, root, inode, path, start, end, NULL,
1039 drop_cache, 0, 0, NULL);
1040 btrfs_free_path(path);
1041 return ret;
1042}
1043
1044static int extent_mergeable(struct extent_buffer *leaf, int slot,
1045 u64 objectid, u64 bytenr, u64 orig_offset,
1046 u64 *start, u64 *end)
1047{
1048 struct btrfs_file_extent_item *fi;
1049 struct btrfs_key key;
1050 u64 extent_end;
1051
1052 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
1053 return 0;
1054
1055 btrfs_item_key_to_cpu(leaf, &key, slot);
1056 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
1057 return 0;
1058
1059 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
1060 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
1061 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
1062 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
1063 btrfs_file_extent_compression(leaf, fi) ||
1064 btrfs_file_extent_encryption(leaf, fi) ||
1065 btrfs_file_extent_other_encoding(leaf, fi))
1066 return 0;
1067
1068 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1069 if ((*start && *start != key.offset) || (*end && *end != extent_end))
1070 return 0;
1071
1072 *start = key.offset;
1073 *end = extent_end;
1074 return 1;
1075}
1076
1077/*
1078 * Mark extent in the range start - end as written.
1079 *
1080 * This changes extent type from 'pre-allocated' to 'regular'. If only
1081 * part of extent is marked as written, the extent will be split into
1082 * two or three.
1083 */
1084int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
1085 struct inode *inode, u64 start, u64 end)
1086{
1087 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1088 struct btrfs_root *root = BTRFS_I(inode)->root;
1089 struct extent_buffer *leaf;
1090 struct btrfs_path *path;
1091 struct btrfs_file_extent_item *fi;
1092 struct btrfs_key key;
1093 struct btrfs_key new_key;
1094 u64 bytenr;
1095 u64 num_bytes;
1096 u64 extent_end;
1097 u64 orig_offset;
1098 u64 other_start;
1099 u64 other_end;
1100 u64 split;
1101 int del_nr = 0;
1102 int del_slot = 0;
1103 int recow;
1104 int ret;
1105 u64 ino = btrfs_ino(inode);
1106
1107 path = btrfs_alloc_path();
1108 if (!path)
1109 return -ENOMEM;
1110again:
1111 recow = 0;
1112 split = start;
1113 key.objectid = ino;
1114 key.type = BTRFS_EXTENT_DATA_KEY;
1115 key.offset = split;
1116
1117 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1118 if (ret < 0)
1119 goto out;
1120 if (ret > 0 && path->slots[0] > 0)
1121 path->slots[0]--;
1122
1123 leaf = path->nodes[0];
1124 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1125 if (key.objectid != ino ||
1126 key.type != BTRFS_EXTENT_DATA_KEY) {
1127 ret = -EINVAL;
1128 btrfs_abort_transaction(trans, ret);
1129 goto out;
1130 }
1131 fi = btrfs_item_ptr(leaf, path->slots[0],
1132 struct btrfs_file_extent_item);
1133 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_PREALLOC) {
1134 ret = -EINVAL;
1135 btrfs_abort_transaction(trans, ret);
1136 goto out;
1137 }
1138 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1139 if (key.offset > start || extent_end < end) {
1140 ret = -EINVAL;
1141 btrfs_abort_transaction(trans, ret);
1142 goto out;
1143 }
1144
1145 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1146 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1147 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
1148 memcpy(&new_key, &key, sizeof(new_key));
1149
1150 if (start == key.offset && end < extent_end) {
1151 other_start = 0;
1152 other_end = start;
1153 if (extent_mergeable(leaf, path->slots[0] - 1,
1154 ino, bytenr, orig_offset,
1155 &other_start, &other_end)) {
1156 new_key.offset = end;
1157 btrfs_set_item_key_safe(fs_info, path, &new_key);
1158 fi = btrfs_item_ptr(leaf, path->slots[0],
1159 struct btrfs_file_extent_item);
1160 btrfs_set_file_extent_generation(leaf, fi,
1161 trans->transid);
1162 btrfs_set_file_extent_num_bytes(leaf, fi,
1163 extent_end - end);
1164 btrfs_set_file_extent_offset(leaf, fi,
1165 end - orig_offset);
1166 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1167 struct btrfs_file_extent_item);
1168 btrfs_set_file_extent_generation(leaf, fi,
1169 trans->transid);
1170 btrfs_set_file_extent_num_bytes(leaf, fi,
1171 end - other_start);
1172 btrfs_mark_buffer_dirty(leaf);
1173 goto out;
1174 }
1175 }
1176
1177 if (start > key.offset && end == extent_end) {
1178 other_start = end;
1179 other_end = 0;
1180 if (extent_mergeable(leaf, path->slots[0] + 1,
1181 ino, bytenr, orig_offset,
1182 &other_start, &other_end)) {
1183 fi = btrfs_item_ptr(leaf, path->slots[0],
1184 struct btrfs_file_extent_item);
1185 btrfs_set_file_extent_num_bytes(leaf, fi,
1186 start - key.offset);
1187 btrfs_set_file_extent_generation(leaf, fi,
1188 trans->transid);
1189 path->slots[0]++;
1190 new_key.offset = start;
1191 btrfs_set_item_key_safe(fs_info, path, &new_key);
1192
1193 fi = btrfs_item_ptr(leaf, path->slots[0],
1194 struct btrfs_file_extent_item);
1195 btrfs_set_file_extent_generation(leaf, fi,
1196 trans->transid);
1197 btrfs_set_file_extent_num_bytes(leaf, fi,
1198 other_end - start);
1199 btrfs_set_file_extent_offset(leaf, fi,
1200 start - orig_offset);
1201 btrfs_mark_buffer_dirty(leaf);
1202 goto out;
1203 }
1204 }
1205
1206 while (start > key.offset || end < extent_end) {
1207 if (key.offset == start)
1208 split = end;
1209
1210 new_key.offset = split;
1211 ret = btrfs_duplicate_item(trans, root, path, &new_key);
1212 if (ret == -EAGAIN) {
1213 btrfs_release_path(path);
1214 goto again;
1215 }
1216 if (ret < 0) {
1217 btrfs_abort_transaction(trans, ret);
1218 goto out;
1219 }
1220
1221 leaf = path->nodes[0];
1222 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1223 struct btrfs_file_extent_item);
1224 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1225 btrfs_set_file_extent_num_bytes(leaf, fi,
1226 split - key.offset);
1227
1228 fi = btrfs_item_ptr(leaf, path->slots[0],
1229 struct btrfs_file_extent_item);
1230
1231 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1232 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
1233 btrfs_set_file_extent_num_bytes(leaf, fi,
1234 extent_end - split);
1235 btrfs_mark_buffer_dirty(leaf);
1236
1237 ret = btrfs_inc_extent_ref(trans, fs_info, bytenr, num_bytes,
1238 0, root->root_key.objectid,
1239 ino, orig_offset);
1240 if (ret) {
1241 btrfs_abort_transaction(trans, ret);
1242 goto out;
1243 }
1244
1245 if (split == start) {
1246 key.offset = start;
1247 } else {
1248 if (start != key.offset) {
1249 ret = -EINVAL;
1250 btrfs_abort_transaction(trans, ret);
1251 goto out;
1252 }
1253 path->slots[0]--;
1254 extent_end = end;
1255 }
1256 recow = 1;
1257 }
1258
1259 other_start = end;
1260 other_end = 0;
1261 if (extent_mergeable(leaf, path->slots[0] + 1,
1262 ino, bytenr, orig_offset,
1263 &other_start, &other_end)) {
1264 if (recow) {
1265 btrfs_release_path(path);
1266 goto again;
1267 }
1268 extent_end = other_end;
1269 del_slot = path->slots[0] + 1;
1270 del_nr++;
1271 ret = btrfs_free_extent(trans, fs_info, bytenr, num_bytes,
1272 0, root->root_key.objectid,
1273 ino, orig_offset);
1274 if (ret) {
1275 btrfs_abort_transaction(trans, ret);
1276 goto out;
1277 }
1278 }
1279 other_start = 0;
1280 other_end = start;
1281 if (extent_mergeable(leaf, path->slots[0] - 1,
1282 ino, bytenr, orig_offset,
1283 &other_start, &other_end)) {
1284 if (recow) {
1285 btrfs_release_path(path);
1286 goto again;
1287 }
1288 key.offset = other_start;
1289 del_slot = path->slots[0];
1290 del_nr++;
1291 ret = btrfs_free_extent(trans, fs_info, bytenr, num_bytes,
1292 0, root->root_key.objectid,
1293 ino, orig_offset);
1294 if (ret) {
1295 btrfs_abort_transaction(trans, ret);
1296 goto out;
1297 }
1298 }
1299 if (del_nr == 0) {
1300 fi = btrfs_item_ptr(leaf, path->slots[0],
1301 struct btrfs_file_extent_item);
1302 btrfs_set_file_extent_type(leaf, fi,
1303 BTRFS_FILE_EXTENT_REG);
1304 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1305 btrfs_mark_buffer_dirty(leaf);
1306 } else {
1307 fi = btrfs_item_ptr(leaf, del_slot - 1,
1308 struct btrfs_file_extent_item);
1309 btrfs_set_file_extent_type(leaf, fi,
1310 BTRFS_FILE_EXTENT_REG);
1311 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1312 btrfs_set_file_extent_num_bytes(leaf, fi,
1313 extent_end - key.offset);
1314 btrfs_mark_buffer_dirty(leaf);
1315
1316 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1317 if (ret < 0) {
1318 btrfs_abort_transaction(trans, ret);
1319 goto out;
1320 }
1321 }
1322out:
1323 btrfs_free_path(path);
1324 return 0;
1325}
1326
1327/*
1328 * on error we return an unlocked page and the error value
1329 * on success we return a locked page and 0
1330 */
1331static int prepare_uptodate_page(struct inode *inode,
1332 struct page *page, u64 pos,
1333 bool force_uptodate)
1334{
1335 int ret = 0;
1336
1337 if (((pos & (PAGE_SIZE - 1)) || force_uptodate) &&
1338 !PageUptodate(page)) {
1339 ret = btrfs_readpage(NULL, page);
1340 if (ret)
1341 return ret;
1342 lock_page(page);
1343 if (!PageUptodate(page)) {
1344 unlock_page(page);
1345 return -EIO;
1346 }
1347 if (page->mapping != inode->i_mapping) {
1348 unlock_page(page);
1349 return -EAGAIN;
1350 }
1351 }
1352 return 0;
1353}
1354
1355/*
1356 * this just gets pages into the page cache and locks them down.
1357 */
1358static noinline int prepare_pages(struct inode *inode, struct page **pages,
1359 size_t num_pages, loff_t pos,
1360 size_t write_bytes, bool force_uptodate)
1361{
1362 int i;
1363 unsigned long index = pos >> PAGE_SHIFT;
1364 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1365 int err = 0;
1366 int faili;
1367
1368 for (i = 0; i < num_pages; i++) {
1369again:
1370 pages[i] = find_or_create_page(inode->i_mapping, index + i,
1371 mask | __GFP_WRITE);
1372 if (!pages[i]) {
1373 faili = i - 1;
1374 err = -ENOMEM;
1375 goto fail;
1376 }
1377
1378 if (i == 0)
1379 err = prepare_uptodate_page(inode, pages[i], pos,
1380 force_uptodate);
1381 if (!err && i == num_pages - 1)
1382 err = prepare_uptodate_page(inode, pages[i],
1383 pos + write_bytes, false);
1384 if (err) {
1385 put_page(pages[i]);
1386 if (err == -EAGAIN) {
1387 err = 0;
1388 goto again;
1389 }
1390 faili = i - 1;
1391 goto fail;
1392 }
1393 wait_on_page_writeback(pages[i]);
1394 }
1395
1396 return 0;
1397fail:
1398 while (faili >= 0) {
1399 unlock_page(pages[faili]);
1400 put_page(pages[faili]);
1401 faili--;
1402 }
1403 return err;
1404
1405}
1406
1407/*
1408 * This function locks the extent and properly waits for data=ordered extents
1409 * to finish before allowing the pages to be modified if need.
1410 *
1411 * The return value:
1412 * 1 - the extent is locked
1413 * 0 - the extent is not locked, and everything is OK
1414 * -EAGAIN - need re-prepare the pages
1415 * the other < 0 number - Something wrong happens
1416 */
1417static noinline int
1418lock_and_cleanup_extent_if_need(struct inode *inode, struct page **pages,
1419 size_t num_pages, loff_t pos,
1420 size_t write_bytes,
1421 u64 *lockstart, u64 *lockend,
1422 struct extent_state **cached_state)
1423{
1424 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1425 u64 start_pos;
1426 u64 last_pos;
1427 int i;
1428 int ret = 0;
1429
1430 start_pos = round_down(pos, fs_info->sectorsize);
1431 last_pos = start_pos
1432 + round_up(pos + write_bytes - start_pos,
1433 fs_info->sectorsize) - 1;
1434
1435 if (start_pos < inode->i_size) {
1436 struct btrfs_ordered_extent *ordered;
1437 lock_extent_bits(&BTRFS_I(inode)->io_tree,
1438 start_pos, last_pos, cached_state);
1439 ordered = btrfs_lookup_ordered_range(inode, start_pos,
1440 last_pos - start_pos + 1);
1441 if (ordered &&
1442 ordered->file_offset + ordered->len > start_pos &&
1443 ordered->file_offset <= last_pos) {
1444 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1445 start_pos, last_pos,
1446 cached_state, GFP_NOFS);
1447 for (i = 0; i < num_pages; i++) {
1448 unlock_page(pages[i]);
1449 put_page(pages[i]);
1450 }
1451 btrfs_start_ordered_extent(inode, ordered, 1);
1452 btrfs_put_ordered_extent(ordered);
1453 return -EAGAIN;
1454 }
1455 if (ordered)
1456 btrfs_put_ordered_extent(ordered);
1457
1458 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
1459 last_pos, EXTENT_DIRTY | EXTENT_DELALLOC |
1460 EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
1461 0, 0, cached_state, GFP_NOFS);
1462 *lockstart = start_pos;
1463 *lockend = last_pos;
1464 ret = 1;
1465 }
1466
1467 for (i = 0; i < num_pages; i++) {
1468 if (clear_page_dirty_for_io(pages[i]))
1469 account_page_redirty(pages[i]);
1470 set_page_extent_mapped(pages[i]);
1471 WARN_ON(!PageLocked(pages[i]));
1472 }
1473
1474 return ret;
1475}
1476
1477static noinline int check_can_nocow(struct inode *inode, loff_t pos,
1478 size_t *write_bytes)
1479{
1480 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1481 struct btrfs_root *root = BTRFS_I(inode)->root;
1482 struct btrfs_ordered_extent *ordered;
1483 u64 lockstart, lockend;
1484 u64 num_bytes;
1485 int ret;
1486
1487 ret = btrfs_start_write_no_snapshoting(root);
1488 if (!ret)
1489 return -ENOSPC;
1490
1491 lockstart = round_down(pos, fs_info->sectorsize);
1492 lockend = round_up(pos + *write_bytes,
1493 fs_info->sectorsize) - 1;
1494
1495 while (1) {
1496 lock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1497 ordered = btrfs_lookup_ordered_range(inode, lockstart,
1498 lockend - lockstart + 1);
1499 if (!ordered) {
1500 break;
1501 }
1502 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1503 btrfs_start_ordered_extent(inode, ordered, 1);
1504 btrfs_put_ordered_extent(ordered);
1505 }
1506
1507 num_bytes = lockend - lockstart + 1;
1508 ret = can_nocow_extent(inode, lockstart, &num_bytes, NULL, NULL, NULL);
1509 if (ret <= 0) {
1510 ret = 0;
1511 btrfs_end_write_no_snapshoting(root);
1512 } else {
1513 *write_bytes = min_t(size_t, *write_bytes ,
1514 num_bytes - pos + lockstart);
1515 }
1516
1517 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1518
1519 return ret;
1520}
1521
1522static noinline ssize_t __btrfs_buffered_write(struct file *file,
1523 struct iov_iter *i,
1524 loff_t pos)
1525{
1526 struct inode *inode = file_inode(file);
1527 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1528 struct btrfs_root *root = BTRFS_I(inode)->root;
1529 struct page **pages = NULL;
1530 struct extent_state *cached_state = NULL;
1531 u64 release_bytes = 0;
1532 u64 lockstart;
1533 u64 lockend;
1534 size_t num_written = 0;
1535 int nrptrs;
1536 int ret = 0;
1537 bool only_release_metadata = false;
1538 bool force_page_uptodate = false;
1539 bool need_unlock;
1540
1541 nrptrs = min(DIV_ROUND_UP(iov_iter_count(i), PAGE_SIZE),
1542 PAGE_SIZE / (sizeof(struct page *)));
1543 nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
1544 nrptrs = max(nrptrs, 8);
1545 pages = kmalloc_array(nrptrs, sizeof(struct page *), GFP_KERNEL);
1546 if (!pages)
1547 return -ENOMEM;
1548
1549 while (iov_iter_count(i) > 0) {
1550 size_t offset = pos & (PAGE_SIZE - 1);
1551 size_t sector_offset;
1552 size_t write_bytes = min(iov_iter_count(i),
1553 nrptrs * (size_t)PAGE_SIZE -
1554 offset);
1555 size_t num_pages = DIV_ROUND_UP(write_bytes + offset,
1556 PAGE_SIZE);
1557 size_t reserve_bytes;
1558 size_t dirty_pages;
1559 size_t copied;
1560 size_t dirty_sectors;
1561 size_t num_sectors;
1562
1563 WARN_ON(num_pages > nrptrs);
1564
1565 /*
1566 * Fault pages before locking them in prepare_pages
1567 * to avoid recursive lock
1568 */
1569 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1570 ret = -EFAULT;
1571 break;
1572 }
1573
1574 sector_offset = pos & (fs_info->sectorsize - 1);
1575 reserve_bytes = round_up(write_bytes + sector_offset,
1576 fs_info->sectorsize);
1577
1578 ret = btrfs_check_data_free_space(inode, pos, write_bytes);
1579 if (ret < 0) {
1580 if ((BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
1581 BTRFS_INODE_PREALLOC)) &&
1582 check_can_nocow(inode, pos, &write_bytes) > 0) {
1583 /*
1584 * For nodata cow case, no need to reserve
1585 * data space.
1586 */
1587 only_release_metadata = true;
1588 /*
1589 * our prealloc extent may be smaller than
1590 * write_bytes, so scale down.
1591 */
1592 num_pages = DIV_ROUND_UP(write_bytes + offset,
1593 PAGE_SIZE);
1594 reserve_bytes = round_up(write_bytes +
1595 sector_offset,
1596 fs_info->sectorsize);
1597 } else {
1598 break;
1599 }
1600 }
1601
1602 ret = btrfs_delalloc_reserve_metadata(inode, reserve_bytes);
1603 if (ret) {
1604 if (!only_release_metadata)
1605 btrfs_free_reserved_data_space(inode, pos,
1606 write_bytes);
1607 else
1608 btrfs_end_write_no_snapshoting(root);
1609 break;
1610 }
1611
1612 release_bytes = reserve_bytes;
1613 need_unlock = false;
1614again:
1615 /*
1616 * This is going to setup the pages array with the number of
1617 * pages we want, so we don't really need to worry about the
1618 * contents of pages from loop to loop
1619 */
1620 ret = prepare_pages(inode, pages, num_pages,
1621 pos, write_bytes,
1622 force_page_uptodate);
1623 if (ret)
1624 break;
1625
1626 ret = lock_and_cleanup_extent_if_need(inode, pages, num_pages,
1627 pos, write_bytes, &lockstart,
1628 &lockend, &cached_state);
1629 if (ret < 0) {
1630 if (ret == -EAGAIN)
1631 goto again;
1632 break;
1633 } else if (ret > 0) {
1634 need_unlock = true;
1635 ret = 0;
1636 }
1637
1638 copied = btrfs_copy_from_user(pos, write_bytes, pages, i);
1639
1640 num_sectors = BTRFS_BYTES_TO_BLKS(fs_info, reserve_bytes);
1641 dirty_sectors = round_up(copied + sector_offset,
1642 fs_info->sectorsize);
1643 dirty_sectors = BTRFS_BYTES_TO_BLKS(fs_info, dirty_sectors);
1644
1645 /*
1646 * if we have trouble faulting in the pages, fall
1647 * back to one page at a time
1648 */
1649 if (copied < write_bytes)
1650 nrptrs = 1;
1651
1652 if (copied == 0) {
1653 force_page_uptodate = true;
1654 dirty_sectors = 0;
1655 dirty_pages = 0;
1656 } else {
1657 force_page_uptodate = false;
1658 dirty_pages = DIV_ROUND_UP(copied + offset,
1659 PAGE_SIZE);
1660 }
1661
1662 /*
1663 * If we had a short copy we need to release the excess delaloc
1664 * bytes we reserved. We need to increment outstanding_extents
1665 * because btrfs_delalloc_release_space and
1666 * btrfs_delalloc_release_metadata will decrement it, but
1667 * we still have an outstanding extent for the chunk we actually
1668 * managed to copy.
1669 */
1670 if (num_sectors > dirty_sectors) {
1671 /* release everything except the sectors we dirtied */
1672 release_bytes -= dirty_sectors <<
1673 fs_info->sb->s_blocksize_bits;
1674 if (copied > 0) {
1675 spin_lock(&BTRFS_I(inode)->lock);
1676 BTRFS_I(inode)->outstanding_extents++;
1677 spin_unlock(&BTRFS_I(inode)->lock);
1678 }
1679 if (only_release_metadata) {
1680 btrfs_delalloc_release_metadata(inode,
1681 release_bytes);
1682 } else {
1683 u64 __pos;
1684
1685 __pos = round_down(pos,
1686 fs_info->sectorsize) +
1687 (dirty_pages << PAGE_SHIFT);
1688 btrfs_delalloc_release_space(inode, __pos,
1689 release_bytes);
1690 }
1691 }
1692
1693 release_bytes = round_up(copied + sector_offset,
1694 fs_info->sectorsize);
1695
1696 if (copied > 0)
1697 ret = btrfs_dirty_pages(inode, pages, dirty_pages,
1698 pos, copied, NULL);
1699 if (need_unlock)
1700 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1701 lockstart, lockend, &cached_state,
1702 GFP_NOFS);
1703 if (ret) {
1704 btrfs_drop_pages(pages, num_pages);
1705 break;
1706 }
1707
1708 release_bytes = 0;
1709 if (only_release_metadata)
1710 btrfs_end_write_no_snapshoting(root);
1711
1712 if (only_release_metadata && copied > 0) {
1713 lockstart = round_down(pos,
1714 fs_info->sectorsize);
1715 lockend = round_up(pos + copied,
1716 fs_info->sectorsize) - 1;
1717
1718 set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
1719 lockend, EXTENT_NORESERVE, NULL,
1720 NULL, GFP_NOFS);
1721 only_release_metadata = false;
1722 }
1723
1724 btrfs_drop_pages(pages, num_pages);
1725
1726 cond_resched();
1727
1728 balance_dirty_pages_ratelimited(inode->i_mapping);
1729 if (dirty_pages < (fs_info->nodesize >> PAGE_SHIFT) + 1)
1730 btrfs_btree_balance_dirty(fs_info);
1731
1732 pos += copied;
1733 num_written += copied;
1734 }
1735
1736 kfree(pages);
1737
1738 if (release_bytes) {
1739 if (only_release_metadata) {
1740 btrfs_end_write_no_snapshoting(root);
1741 btrfs_delalloc_release_metadata(inode, release_bytes);
1742 } else {
1743 btrfs_delalloc_release_space(inode,
1744 round_down(pos, fs_info->sectorsize),
1745 release_bytes);
1746 }
1747 }
1748
1749 return num_written ? num_written : ret;
1750}
1751
1752static ssize_t __btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
1753{
1754 struct file *file = iocb->ki_filp;
1755 struct inode *inode = file_inode(file);
1756 loff_t pos = iocb->ki_pos;
1757 ssize_t written;
1758 ssize_t written_buffered;
1759 loff_t endbyte;
1760 int err;
1761
1762 written = generic_file_direct_write(iocb, from);
1763
1764 if (written < 0 || !iov_iter_count(from))
1765 return written;
1766
1767 pos += written;
1768 written_buffered = __btrfs_buffered_write(file, from, pos);
1769 if (written_buffered < 0) {
1770 err = written_buffered;
1771 goto out;
1772 }
1773 /*
1774 * Ensure all data is persisted. We want the next direct IO read to be
1775 * able to read what was just written.
1776 */
1777 endbyte = pos + written_buffered - 1;
1778 err = btrfs_fdatawrite_range(inode, pos, endbyte);
1779 if (err)
1780 goto out;
1781 err = filemap_fdatawait_range(inode->i_mapping, pos, endbyte);
1782 if (err)
1783 goto out;
1784 written += written_buffered;
1785 iocb->ki_pos = pos + written_buffered;
1786 invalidate_mapping_pages(file->f_mapping, pos >> PAGE_SHIFT,
1787 endbyte >> PAGE_SHIFT);
1788out:
1789 return written ? written : err;
1790}
1791
1792static void update_time_for_write(struct inode *inode)
1793{
1794 struct timespec now;
1795
1796 if (IS_NOCMTIME(inode))
1797 return;
1798
1799 now = current_time(inode);
1800 if (!timespec_equal(&inode->i_mtime, &now))
1801 inode->i_mtime = now;
1802
1803 if (!timespec_equal(&inode->i_ctime, &now))
1804 inode->i_ctime = now;
1805
1806 if (IS_I_VERSION(inode))
1807 inode_inc_iversion(inode);
1808}
1809
1810static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
1811 struct iov_iter *from)
1812{
1813 struct file *file = iocb->ki_filp;
1814 struct inode *inode = file_inode(file);
1815 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1816 struct btrfs_root *root = BTRFS_I(inode)->root;
1817 u64 start_pos;
1818 u64 end_pos;
1819 ssize_t num_written = 0;
1820 bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
1821 ssize_t err;
1822 loff_t pos;
1823 size_t count;
1824 loff_t oldsize;
1825 int clean_page = 0;
1826
1827 inode_lock(inode);
1828 err = generic_write_checks(iocb, from);
1829 if (err <= 0) {
1830 inode_unlock(inode);
1831 return err;
1832 }
1833
1834 current->backing_dev_info = inode_to_bdi(inode);
1835 err = file_remove_privs(file);
1836 if (err) {
1837 inode_unlock(inode);
1838 goto out;
1839 }
1840
1841 /*
1842 * If BTRFS flips readonly due to some impossible error
1843 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1844 * although we have opened a file as writable, we have
1845 * to stop this write operation to ensure FS consistency.
1846 */
1847 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
1848 inode_unlock(inode);
1849 err = -EROFS;
1850 goto out;
1851 }
1852
1853 /*
1854 * We reserve space for updating the inode when we reserve space for the
1855 * extent we are going to write, so we will enospc out there. We don't
1856 * need to start yet another transaction to update the inode as we will
1857 * update the inode when we finish writing whatever data we write.
1858 */
1859 update_time_for_write(inode);
1860
1861 pos = iocb->ki_pos;
1862 count = iov_iter_count(from);
1863 start_pos = round_down(pos, fs_info->sectorsize);
1864 oldsize = i_size_read(inode);
1865 if (start_pos > oldsize) {
1866 /* Expand hole size to cover write data, preventing empty gap */
1867 end_pos = round_up(pos + count,
1868 fs_info->sectorsize);
1869 err = btrfs_cont_expand(inode, oldsize, end_pos);
1870 if (err) {
1871 inode_unlock(inode);
1872 goto out;
1873 }
1874 if (start_pos > round_up(oldsize, fs_info->sectorsize))
1875 clean_page = 1;
1876 }
1877
1878 if (sync)
1879 atomic_inc(&BTRFS_I(inode)->sync_writers);
1880
1881 if (iocb->ki_flags & IOCB_DIRECT) {
1882 num_written = __btrfs_direct_write(iocb, from);
1883 } else {
1884 num_written = __btrfs_buffered_write(file, from, pos);
1885 if (num_written > 0)
1886 iocb->ki_pos = pos + num_written;
1887 if (clean_page)
1888 pagecache_isize_extended(inode, oldsize,
1889 i_size_read(inode));
1890 }
1891
1892 inode_unlock(inode);
1893
1894 /*
1895 * We also have to set last_sub_trans to the current log transid,
1896 * otherwise subsequent syncs to a file that's been synced in this
1897 * transaction will appear to have already occurred.
1898 */
1899 spin_lock(&BTRFS_I(inode)->lock);
1900 BTRFS_I(inode)->last_sub_trans = root->log_transid;
1901 spin_unlock(&BTRFS_I(inode)->lock);
1902 if (num_written > 0)
1903 num_written = generic_write_sync(iocb, num_written);
1904
1905 if (sync)
1906 atomic_dec(&BTRFS_I(inode)->sync_writers);
1907out:
1908 current->backing_dev_info = NULL;
1909 return num_written ? num_written : err;
1910}
1911
1912int btrfs_release_file(struct inode *inode, struct file *filp)
1913{
1914 if (filp->private_data)
1915 btrfs_ioctl_trans_end(filp);
1916 /*
1917 * ordered_data_close is set by settattr when we are about to truncate
1918 * a file from a non-zero size to a zero size. This tries to
1919 * flush down new bytes that may have been written if the
1920 * application were using truncate to replace a file in place.
1921 */
1922 if (test_and_clear_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
1923 &BTRFS_I(inode)->runtime_flags))
1924 filemap_flush(inode->i_mapping);
1925 return 0;
1926}
1927
1928static int start_ordered_ops(struct inode *inode, loff_t start, loff_t end)
1929{
1930 int ret;
1931
1932 atomic_inc(&BTRFS_I(inode)->sync_writers);
1933 ret = btrfs_fdatawrite_range(inode, start, end);
1934 atomic_dec(&BTRFS_I(inode)->sync_writers);
1935
1936 return ret;
1937}
1938
1939/*
1940 * fsync call for both files and directories. This logs the inode into
1941 * the tree log instead of forcing full commits whenever possible.
1942 *
1943 * It needs to call filemap_fdatawait so that all ordered extent updates are
1944 * in the metadata btree are up to date for copying to the log.
1945 *
1946 * It drops the inode mutex before doing the tree log commit. This is an
1947 * important optimization for directories because holding the mutex prevents
1948 * new operations on the dir while we write to disk.
1949 */
1950int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
1951{
1952 struct dentry *dentry = file_dentry(file);
1953 struct inode *inode = d_inode(dentry);
1954 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1955 struct btrfs_root *root = BTRFS_I(inode)->root;
1956 struct btrfs_trans_handle *trans;
1957 struct btrfs_log_ctx ctx;
1958 int ret = 0;
1959 bool full_sync = 0;
1960 u64 len;
1961
1962 /*
1963 * The range length can be represented by u64, we have to do the typecasts
1964 * to avoid signed overflow if it's [0, LLONG_MAX] eg. from fsync()
1965 */
1966 len = (u64)end - (u64)start + 1;
1967 trace_btrfs_sync_file(file, datasync);
1968
1969 /*
1970 * We write the dirty pages in the range and wait until they complete
1971 * out of the ->i_mutex. If so, we can flush the dirty pages by
1972 * multi-task, and make the performance up. See
1973 * btrfs_wait_ordered_range for an explanation of the ASYNC check.
1974 */
1975 ret = start_ordered_ops(inode, start, end);
1976 if (ret)
1977 return ret;
1978
1979 inode_lock(inode);
1980 atomic_inc(&root->log_batch);
1981 full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1982 &BTRFS_I(inode)->runtime_flags);
1983 /*
1984 * We might have have had more pages made dirty after calling
1985 * start_ordered_ops and before acquiring the inode's i_mutex.
1986 */
1987 if (full_sync) {
1988 /*
1989 * For a full sync, we need to make sure any ordered operations
1990 * start and finish before we start logging the inode, so that
1991 * all extents are persisted and the respective file extent
1992 * items are in the fs/subvol btree.
1993 */
1994 ret = btrfs_wait_ordered_range(inode, start, len);
1995 } else {
1996 /*
1997 * Start any new ordered operations before starting to log the
1998 * inode. We will wait for them to finish in btrfs_sync_log().
1999 *
2000 * Right before acquiring the inode's mutex, we might have new
2001 * writes dirtying pages, which won't immediately start the
2002 * respective ordered operations - that is done through the
2003 * fill_delalloc callbacks invoked from the writepage and
2004 * writepages address space operations. So make sure we start
2005 * all ordered operations before starting to log our inode. Not
2006 * doing this means that while logging the inode, writeback
2007 * could start and invoke writepage/writepages, which would call
2008 * the fill_delalloc callbacks (cow_file_range,
2009 * submit_compressed_extents). These callbacks add first an
2010 * extent map to the modified list of extents and then create
2011 * the respective ordered operation, which means in
2012 * tree-log.c:btrfs_log_inode() we might capture all existing
2013 * ordered operations (with btrfs_get_logged_extents()) before
2014 * the fill_delalloc callback adds its ordered operation, and by
2015 * the time we visit the modified list of extent maps (with
2016 * btrfs_log_changed_extents()), we see and process the extent
2017 * map they created. We then use the extent map to construct a
2018 * file extent item for logging without waiting for the
2019 * respective ordered operation to finish - this file extent
2020 * item points to a disk location that might not have yet been
2021 * written to, containing random data - so after a crash a log
2022 * replay will make our inode have file extent items that point
2023 * to disk locations containing invalid data, as we returned
2024 * success to userspace without waiting for the respective
2025 * ordered operation to finish, because it wasn't captured by
2026 * btrfs_get_logged_extents().
2027 */
2028 ret = start_ordered_ops(inode, start, end);
2029 }
2030 if (ret) {
2031 inode_unlock(inode);
2032 goto out;
2033 }
2034 atomic_inc(&root->log_batch);
2035
2036 /*
2037 * If the last transaction that changed this file was before the current
2038 * transaction and we have the full sync flag set in our inode, we can
2039 * bail out now without any syncing.
2040 *
2041 * Note that we can't bail out if the full sync flag isn't set. This is
2042 * because when the full sync flag is set we start all ordered extents
2043 * and wait for them to fully complete - when they complete they update
2044 * the inode's last_trans field through:
2045 *
2046 * btrfs_finish_ordered_io() ->
2047 * btrfs_update_inode_fallback() ->
2048 * btrfs_update_inode() ->
2049 * btrfs_set_inode_last_trans()
2050 *
2051 * So we are sure that last_trans is up to date and can do this check to
2052 * bail out safely. For the fast path, when the full sync flag is not
2053 * set in our inode, we can not do it because we start only our ordered
2054 * extents and don't wait for them to complete (that is when
2055 * btrfs_finish_ordered_io runs), so here at this point their last_trans
2056 * value might be less than or equals to fs_info->last_trans_committed,
2057 * and setting a speculative last_trans for an inode when a buffered
2058 * write is made (such as fs_info->generation + 1 for example) would not
2059 * be reliable since after setting the value and before fsync is called
2060 * any number of transactions can start and commit (transaction kthread
2061 * commits the current transaction periodically), and a transaction
2062 * commit does not start nor waits for ordered extents to complete.
2063 */
2064 smp_mb();
2065 if (btrfs_inode_in_log(inode, fs_info->generation) ||
2066 (full_sync && BTRFS_I(inode)->last_trans <=
2067 fs_info->last_trans_committed) ||
2068 (!btrfs_have_ordered_extents_in_range(inode, start, len) &&
2069 BTRFS_I(inode)->last_trans
2070 <= fs_info->last_trans_committed)) {
2071 /*
2072 * We've had everything committed since the last time we were
2073 * modified so clear this flag in case it was set for whatever
2074 * reason, it's no longer relevant.
2075 */
2076 clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2077 &BTRFS_I(inode)->runtime_flags);
2078 /*
2079 * An ordered extent might have started before and completed
2080 * already with io errors, in which case the inode was not
2081 * updated and we end up here. So check the inode's mapping
2082 * flags for any errors that might have happened while doing
2083 * writeback of file data.
2084 */
2085 ret = filemap_check_errors(inode->i_mapping);
2086 inode_unlock(inode);
2087 goto out;
2088 }
2089
2090 /*
2091 * ok we haven't committed the transaction yet, lets do a commit
2092 */
2093 if (file->private_data)
2094 btrfs_ioctl_trans_end(file);
2095
2096 /*
2097 * We use start here because we will need to wait on the IO to complete
2098 * in btrfs_sync_log, which could require joining a transaction (for
2099 * example checking cross references in the nocow path). If we use join
2100 * here we could get into a situation where we're waiting on IO to
2101 * happen that is blocked on a transaction trying to commit. With start
2102 * we inc the extwriter counter, so we wait for all extwriters to exit
2103 * before we start blocking join'ers. This comment is to keep somebody
2104 * from thinking they are super smart and changing this to
2105 * btrfs_join_transaction *cough*Josef*cough*.
2106 */
2107 trans = btrfs_start_transaction(root, 0);
2108 if (IS_ERR(trans)) {
2109 ret = PTR_ERR(trans);
2110 inode_unlock(inode);
2111 goto out;
2112 }
2113 trans->sync = true;
2114
2115 btrfs_init_log_ctx(&ctx, inode);
2116
2117 ret = btrfs_log_dentry_safe(trans, root, dentry, start, end, &ctx);
2118 if (ret < 0) {
2119 /* Fallthrough and commit/free transaction. */
2120 ret = 1;
2121 }
2122
2123 /* we've logged all the items and now have a consistent
2124 * version of the file in the log. It is possible that
2125 * someone will come in and modify the file, but that's
2126 * fine because the log is consistent on disk, and we
2127 * have references to all of the file's extents
2128 *
2129 * It is possible that someone will come in and log the
2130 * file again, but that will end up using the synchronization
2131 * inside btrfs_sync_log to keep things safe.
2132 */
2133 inode_unlock(inode);
2134
2135 /*
2136 * If any of the ordered extents had an error, just return it to user
2137 * space, so that the application knows some writes didn't succeed and
2138 * can take proper action (retry for e.g.). Blindly committing the
2139 * transaction in this case, would fool userspace that everything was
2140 * successful. And we also want to make sure our log doesn't contain
2141 * file extent items pointing to extents that weren't fully written to -
2142 * just like in the non fast fsync path, where we check for the ordered
2143 * operation's error flag before writing to the log tree and return -EIO
2144 * if any of them had this flag set (btrfs_wait_ordered_range) -
2145 * therefore we need to check for errors in the ordered operations,
2146 * which are indicated by ctx.io_err.
2147 */
2148 if (ctx.io_err) {
2149 btrfs_end_transaction(trans);
2150 ret = ctx.io_err;
2151 goto out;
2152 }
2153
2154 if (ret != BTRFS_NO_LOG_SYNC) {
2155 if (!ret) {
2156 ret = btrfs_sync_log(trans, root, &ctx);
2157 if (!ret) {
2158 ret = btrfs_end_transaction(trans);
2159 goto out;
2160 }
2161 }
2162 if (!full_sync) {
2163 ret = btrfs_wait_ordered_range(inode, start, len);
2164 if (ret) {
2165 btrfs_end_transaction(trans);
2166 goto out;
2167 }
2168 }
2169 ret = btrfs_commit_transaction(trans);
2170 } else {
2171 ret = btrfs_end_transaction(trans);
2172 }
2173out:
2174 return ret > 0 ? -EIO : ret;
2175}
2176
2177static const struct vm_operations_struct btrfs_file_vm_ops = {
2178 .fault = filemap_fault,
2179 .map_pages = filemap_map_pages,
2180 .page_mkwrite = btrfs_page_mkwrite,
2181};
2182
2183static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
2184{
2185 struct address_space *mapping = filp->f_mapping;
2186
2187 if (!mapping->a_ops->readpage)
2188 return -ENOEXEC;
2189
2190 file_accessed(filp);
2191 vma->vm_ops = &btrfs_file_vm_ops;
2192
2193 return 0;
2194}
2195
2196static int hole_mergeable(struct inode *inode, struct extent_buffer *leaf,
2197 int slot, u64 start, u64 end)
2198{
2199 struct btrfs_file_extent_item *fi;
2200 struct btrfs_key key;
2201
2202 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
2203 return 0;
2204
2205 btrfs_item_key_to_cpu(leaf, &key, slot);
2206 if (key.objectid != btrfs_ino(inode) ||
2207 key.type != BTRFS_EXTENT_DATA_KEY)
2208 return 0;
2209
2210 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
2211
2212 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2213 return 0;
2214
2215 if (btrfs_file_extent_disk_bytenr(leaf, fi))
2216 return 0;
2217
2218 if (key.offset == end)
2219 return 1;
2220 if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start)
2221 return 1;
2222 return 0;
2223}
2224
2225static int fill_holes(struct btrfs_trans_handle *trans, struct inode *inode,
2226 struct btrfs_path *path, u64 offset, u64 end)
2227{
2228 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2229 struct btrfs_root *root = BTRFS_I(inode)->root;
2230 struct extent_buffer *leaf;
2231 struct btrfs_file_extent_item *fi;
2232 struct extent_map *hole_em;
2233 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2234 struct btrfs_key key;
2235 int ret;
2236
2237 if (btrfs_fs_incompat(fs_info, NO_HOLES))
2238 goto out;
2239
2240 key.objectid = btrfs_ino(inode);
2241 key.type = BTRFS_EXTENT_DATA_KEY;
2242 key.offset = offset;
2243
2244 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2245 if (ret <= 0) {
2246 /*
2247 * We should have dropped this offset, so if we find it then
2248 * something has gone horribly wrong.
2249 */
2250 if (ret == 0)
2251 ret = -EINVAL;
2252 return ret;
2253 }
2254
2255 leaf = path->nodes[0];
2256 if (hole_mergeable(inode, leaf, path->slots[0]-1, offset, end)) {
2257 u64 num_bytes;
2258
2259 path->slots[0]--;
2260 fi = btrfs_item_ptr(leaf, path->slots[0],
2261 struct btrfs_file_extent_item);
2262 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) +
2263 end - offset;
2264 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2265 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2266 btrfs_set_file_extent_offset(leaf, fi, 0);
2267 btrfs_mark_buffer_dirty(leaf);
2268 goto out;
2269 }
2270
2271 if (hole_mergeable(inode, leaf, path->slots[0], offset, end)) {
2272 u64 num_bytes;
2273
2274 key.offset = offset;
2275 btrfs_set_item_key_safe(fs_info, path, &key);
2276 fi = btrfs_item_ptr(leaf, path->slots[0],
2277 struct btrfs_file_extent_item);
2278 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
2279 offset;
2280 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2281 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2282 btrfs_set_file_extent_offset(leaf, fi, 0);
2283 btrfs_mark_buffer_dirty(leaf);
2284 goto out;
2285 }
2286 btrfs_release_path(path);
2287
2288 ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
2289 0, 0, end - offset, 0, end - offset,
2290 0, 0, 0);
2291 if (ret)
2292 return ret;
2293
2294out:
2295 btrfs_release_path(path);
2296
2297 hole_em = alloc_extent_map();
2298 if (!hole_em) {
2299 btrfs_drop_extent_cache(inode, offset, end - 1, 0);
2300 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2301 &BTRFS_I(inode)->runtime_flags);
2302 } else {
2303 hole_em->start = offset;
2304 hole_em->len = end - offset;
2305 hole_em->ram_bytes = hole_em->len;
2306 hole_em->orig_start = offset;
2307
2308 hole_em->block_start = EXTENT_MAP_HOLE;
2309 hole_em->block_len = 0;
2310 hole_em->orig_block_len = 0;
2311 hole_em->bdev = fs_info->fs_devices->latest_bdev;
2312 hole_em->compress_type = BTRFS_COMPRESS_NONE;
2313 hole_em->generation = trans->transid;
2314
2315 do {
2316 btrfs_drop_extent_cache(inode, offset, end - 1, 0);
2317 write_lock(&em_tree->lock);
2318 ret = add_extent_mapping(em_tree, hole_em, 1);
2319 write_unlock(&em_tree->lock);
2320 } while (ret == -EEXIST);
2321 free_extent_map(hole_em);
2322 if (ret)
2323 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2324 &BTRFS_I(inode)->runtime_flags);
2325 }
2326
2327 return 0;
2328}
2329
2330/*
2331 * Find a hole extent on given inode and change start/len to the end of hole
2332 * extent.(hole/vacuum extent whose em->start <= start &&
2333 * em->start + em->len > start)
2334 * When a hole extent is found, return 1 and modify start/len.
2335 */
2336static int find_first_non_hole(struct inode *inode, u64 *start, u64 *len)
2337{
2338 struct extent_map *em;
2339 int ret = 0;
2340
2341 em = btrfs_get_extent(inode, NULL, 0, *start, *len, 0);
2342 if (IS_ERR_OR_NULL(em)) {
2343 if (!em)
2344 ret = -ENOMEM;
2345 else
2346 ret = PTR_ERR(em);
2347 return ret;
2348 }
2349
2350 /* Hole or vacuum extent(only exists in no-hole mode) */
2351 if (em->block_start == EXTENT_MAP_HOLE) {
2352 ret = 1;
2353 *len = em->start + em->len > *start + *len ?
2354 0 : *start + *len - em->start - em->len;
2355 *start = em->start + em->len;
2356 }
2357 free_extent_map(em);
2358 return ret;
2359}
2360
2361static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
2362{
2363 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2364 struct btrfs_root *root = BTRFS_I(inode)->root;
2365 struct extent_state *cached_state = NULL;
2366 struct btrfs_path *path;
2367 struct btrfs_block_rsv *rsv;
2368 struct btrfs_trans_handle *trans;
2369 u64 lockstart;
2370 u64 lockend;
2371 u64 tail_start;
2372 u64 tail_len;
2373 u64 orig_start = offset;
2374 u64 cur_offset;
2375 u64 min_size = btrfs_calc_trans_metadata_size(fs_info, 1);
2376 u64 drop_end;
2377 int ret = 0;
2378 int err = 0;
2379 unsigned int rsv_count;
2380 bool same_block;
2381 bool no_holes = btrfs_fs_incompat(fs_info, NO_HOLES);
2382 u64 ino_size;
2383 bool truncated_block = false;
2384 bool updated_inode = false;
2385
2386 ret = btrfs_wait_ordered_range(inode, offset, len);
2387 if (ret)
2388 return ret;
2389
2390 inode_lock(inode);
2391 ino_size = round_up(inode->i_size, fs_info->sectorsize);
2392 ret = find_first_non_hole(inode, &offset, &len);
2393 if (ret < 0)
2394 goto out_only_mutex;
2395 if (ret && !len) {
2396 /* Already in a large hole */
2397 ret = 0;
2398 goto out_only_mutex;
2399 }
2400
2401 lockstart = round_up(offset, btrfs_inode_sectorsize(inode));
2402 lockend = round_down(offset + len,
2403 btrfs_inode_sectorsize(inode)) - 1;
2404 same_block = (BTRFS_BYTES_TO_BLKS(fs_info, offset))
2405 == (BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1));
2406 /*
2407 * We needn't truncate any block which is beyond the end of the file
2408 * because we are sure there is no data there.
2409 */
2410 /*
2411 * Only do this if we are in the same block and we aren't doing the
2412 * entire block.
2413 */
2414 if (same_block && len < fs_info->sectorsize) {
2415 if (offset < ino_size) {
2416 truncated_block = true;
2417 ret = btrfs_truncate_block(inode, offset, len, 0);
2418 } else {
2419 ret = 0;
2420 }
2421 goto out_only_mutex;
2422 }
2423
2424 /* zero back part of the first block */
2425 if (offset < ino_size) {
2426 truncated_block = true;
2427 ret = btrfs_truncate_block(inode, offset, 0, 0);
2428 if (ret) {
2429 inode_unlock(inode);
2430 return ret;
2431 }
2432 }
2433
2434 /* Check the aligned pages after the first unaligned page,
2435 * if offset != orig_start, which means the first unaligned page
2436 * including several following pages are already in holes,
2437 * the extra check can be skipped */
2438 if (offset == orig_start) {
2439 /* after truncate page, check hole again */
2440 len = offset + len - lockstart;
2441 offset = lockstart;
2442 ret = find_first_non_hole(inode, &offset, &len);
2443 if (ret < 0)
2444 goto out_only_mutex;
2445 if (ret && !len) {
2446 ret = 0;
2447 goto out_only_mutex;
2448 }
2449 lockstart = offset;
2450 }
2451
2452 /* Check the tail unaligned part is in a hole */
2453 tail_start = lockend + 1;
2454 tail_len = offset + len - tail_start;
2455 if (tail_len) {
2456 ret = find_first_non_hole(inode, &tail_start, &tail_len);
2457 if (unlikely(ret < 0))
2458 goto out_only_mutex;
2459 if (!ret) {
2460 /* zero the front end of the last page */
2461 if (tail_start + tail_len < ino_size) {
2462 truncated_block = true;
2463 ret = btrfs_truncate_block(inode,
2464 tail_start + tail_len,
2465 0, 1);
2466 if (ret)
2467 goto out_only_mutex;
2468 }
2469 }
2470 }
2471
2472 if (lockend < lockstart) {
2473 ret = 0;
2474 goto out_only_mutex;
2475 }
2476
2477 while (1) {
2478 struct btrfs_ordered_extent *ordered;
2479
2480 truncate_pagecache_range(inode, lockstart, lockend);
2481
2482 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2483 &cached_state);
2484 ordered = btrfs_lookup_first_ordered_extent(inode, lockend);
2485
2486 /*
2487 * We need to make sure we have no ordered extents in this range
2488 * and nobody raced in and read a page in this range, if we did
2489 * we need to try again.
2490 */
2491 if ((!ordered ||
2492 (ordered->file_offset + ordered->len <= lockstart ||
2493 ordered->file_offset > lockend)) &&
2494 !btrfs_page_exists_in_range(inode, lockstart, lockend)) {
2495 if (ordered)
2496 btrfs_put_ordered_extent(ordered);
2497 break;
2498 }
2499 if (ordered)
2500 btrfs_put_ordered_extent(ordered);
2501 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
2502 lockend, &cached_state, GFP_NOFS);
2503 ret = btrfs_wait_ordered_range(inode, lockstart,
2504 lockend - lockstart + 1);
2505 if (ret) {
2506 inode_unlock(inode);
2507 return ret;
2508 }
2509 }
2510
2511 path = btrfs_alloc_path();
2512 if (!path) {
2513 ret = -ENOMEM;
2514 goto out;
2515 }
2516
2517 rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
2518 if (!rsv) {
2519 ret = -ENOMEM;
2520 goto out_free;
2521 }
2522 rsv->size = btrfs_calc_trans_metadata_size(fs_info, 1);
2523 rsv->failfast = 1;
2524
2525 /*
2526 * 1 - update the inode
2527 * 1 - removing the extents in the range
2528 * 1 - adding the hole extent if no_holes isn't set
2529 */
2530 rsv_count = no_holes ? 2 : 3;
2531 trans = btrfs_start_transaction(root, rsv_count);
2532 if (IS_ERR(trans)) {
2533 err = PTR_ERR(trans);
2534 goto out_free;
2535 }
2536
2537 ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
2538 min_size, 0);
2539 BUG_ON(ret);
2540 trans->block_rsv = rsv;
2541
2542 cur_offset = lockstart;
2543 len = lockend - cur_offset;
2544 while (cur_offset < lockend) {
2545 ret = __btrfs_drop_extents(trans, root, inode, path,
2546 cur_offset, lockend + 1,
2547 &drop_end, 1, 0, 0, NULL);
2548 if (ret != -ENOSPC)
2549 break;
2550
2551 trans->block_rsv = &fs_info->trans_block_rsv;
2552
2553 if (cur_offset < drop_end && cur_offset < ino_size) {
2554 ret = fill_holes(trans, inode, path, cur_offset,
2555 drop_end);
2556 if (ret) {
2557 /*
2558 * If we failed then we didn't insert our hole
2559 * entries for the area we dropped, so now the
2560 * fs is corrupted, so we must abort the
2561 * transaction.
2562 */
2563 btrfs_abort_transaction(trans, ret);
2564 err = ret;
2565 break;
2566 }
2567 }
2568
2569 cur_offset = drop_end;
2570
2571 ret = btrfs_update_inode(trans, root, inode);
2572 if (ret) {
2573 err = ret;
2574 break;
2575 }
2576
2577 btrfs_end_transaction(trans);
2578 btrfs_btree_balance_dirty(fs_info);
2579
2580 trans = btrfs_start_transaction(root, rsv_count);
2581 if (IS_ERR(trans)) {
2582 ret = PTR_ERR(trans);
2583 trans = NULL;
2584 break;
2585 }
2586
2587 ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
2588 rsv, min_size, 0);
2589 BUG_ON(ret); /* shouldn't happen */
2590 trans->block_rsv = rsv;
2591
2592 ret = find_first_non_hole(inode, &cur_offset, &len);
2593 if (unlikely(ret < 0))
2594 break;
2595 if (ret && !len) {
2596 ret = 0;
2597 break;
2598 }
2599 }
2600
2601 if (ret) {
2602 err = ret;
2603 goto out_trans;
2604 }
2605
2606 trans->block_rsv = &fs_info->trans_block_rsv;
2607 /*
2608 * If we are using the NO_HOLES feature we might have had already an
2609 * hole that overlaps a part of the region [lockstart, lockend] and
2610 * ends at (or beyond) lockend. Since we have no file extent items to
2611 * represent holes, drop_end can be less than lockend and so we must
2612 * make sure we have an extent map representing the existing hole (the
2613 * call to __btrfs_drop_extents() might have dropped the existing extent
2614 * map representing the existing hole), otherwise the fast fsync path
2615 * will not record the existence of the hole region
2616 * [existing_hole_start, lockend].
2617 */
2618 if (drop_end <= lockend)
2619 drop_end = lockend + 1;
2620 /*
2621 * Don't insert file hole extent item if it's for a range beyond eof
2622 * (because it's useless) or if it represents a 0 bytes range (when
2623 * cur_offset == drop_end).
2624 */
2625 if (cur_offset < ino_size && cur_offset < drop_end) {
2626 ret = fill_holes(trans, inode, path, cur_offset, drop_end);
2627 if (ret) {
2628 /* Same comment as above. */
2629 btrfs_abort_transaction(trans, ret);
2630 err = ret;
2631 goto out_trans;
2632 }
2633 }
2634
2635out_trans:
2636 if (!trans)
2637 goto out_free;
2638
2639 inode_inc_iversion(inode);
2640 inode->i_mtime = inode->i_ctime = current_time(inode);
2641
2642 trans->block_rsv = &fs_info->trans_block_rsv;
2643 ret = btrfs_update_inode(trans, root, inode);
2644 updated_inode = true;
2645 btrfs_end_transaction(trans);
2646 btrfs_btree_balance_dirty(fs_info);
2647out_free:
2648 btrfs_free_path(path);
2649 btrfs_free_block_rsv(fs_info, rsv);
2650out:
2651 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2652 &cached_state, GFP_NOFS);
2653out_only_mutex:
2654 if (!updated_inode && truncated_block && !ret && !err) {
2655 /*
2656 * If we only end up zeroing part of a page, we still need to
2657 * update the inode item, so that all the time fields are
2658 * updated as well as the necessary btrfs inode in memory fields
2659 * for detecting, at fsync time, if the inode isn't yet in the
2660 * log tree or it's there but not up to date.
2661 */
2662 trans = btrfs_start_transaction(root, 1);
2663 if (IS_ERR(trans)) {
2664 err = PTR_ERR(trans);
2665 } else {
2666 err = btrfs_update_inode(trans, root, inode);
2667 ret = btrfs_end_transaction(trans);
2668 }
2669 }
2670 inode_unlock(inode);
2671 if (ret && !err)
2672 err = ret;
2673 return err;
2674}
2675
2676/* Helper structure to record which range is already reserved */
2677struct falloc_range {
2678 struct list_head list;
2679 u64 start;
2680 u64 len;
2681};
2682
2683/*
2684 * Helper function to add falloc range
2685 *
2686 * Caller should have locked the larger range of extent containing
2687 * [start, len)
2688 */
2689static int add_falloc_range(struct list_head *head, u64 start, u64 len)
2690{
2691 struct falloc_range *prev = NULL;
2692 struct falloc_range *range = NULL;
2693
2694 if (list_empty(head))
2695 goto insert;
2696
2697 /*
2698 * As fallocate iterate by bytenr order, we only need to check
2699 * the last range.
2700 */
2701 prev = list_entry(head->prev, struct falloc_range, list);
2702 if (prev->start + prev->len == start) {
2703 prev->len += len;
2704 return 0;
2705 }
2706insert:
2707 range = kmalloc(sizeof(*range), GFP_KERNEL);
2708 if (!range)
2709 return -ENOMEM;
2710 range->start = start;
2711 range->len = len;
2712 list_add_tail(&range->list, head);
2713 return 0;
2714}
2715
2716static long btrfs_fallocate(struct file *file, int mode,
2717 loff_t offset, loff_t len)
2718{
2719 struct inode *inode = file_inode(file);
2720 struct extent_state *cached_state = NULL;
2721 struct falloc_range *range;
2722 struct falloc_range *tmp;
2723 struct list_head reserve_list;
2724 u64 cur_offset;
2725 u64 last_byte;
2726 u64 alloc_start;
2727 u64 alloc_end;
2728 u64 alloc_hint = 0;
2729 u64 locked_end;
2730 u64 actual_end = 0;
2731 struct extent_map *em;
2732 int blocksize = btrfs_inode_sectorsize(inode);
2733 int ret;
2734
2735 alloc_start = round_down(offset, blocksize);
2736 alloc_end = round_up(offset + len, blocksize);
2737 cur_offset = alloc_start;
2738
2739 /* Make sure we aren't being give some crap mode */
2740 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
2741 return -EOPNOTSUPP;
2742
2743 if (mode & FALLOC_FL_PUNCH_HOLE)
2744 return btrfs_punch_hole(inode, offset, len);
2745
2746 /*
2747 * Only trigger disk allocation, don't trigger qgroup reserve
2748 *
2749 * For qgroup space, it will be checked later.
2750 */
2751 ret = btrfs_alloc_data_chunk_ondemand(inode, alloc_end - alloc_start);
2752 if (ret < 0)
2753 return ret;
2754
2755 inode_lock(inode);
2756
2757 if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) {
2758 ret = inode_newsize_ok(inode, offset + len);
2759 if (ret)
2760 goto out;
2761 }
2762
2763 /*
2764 * TODO: Move these two operations after we have checked
2765 * accurate reserved space, or fallocate can still fail but
2766 * with page truncated or size expanded.
2767 *
2768 * But that's a minor problem and won't do much harm BTW.
2769 */
2770 if (alloc_start > inode->i_size) {
2771 ret = btrfs_cont_expand(inode, i_size_read(inode),
2772 alloc_start);
2773 if (ret)
2774 goto out;
2775 } else if (offset + len > inode->i_size) {
2776 /*
2777 * If we are fallocating from the end of the file onward we
2778 * need to zero out the end of the block if i_size lands in the
2779 * middle of a block.
2780 */
2781 ret = btrfs_truncate_block(inode, inode->i_size, 0, 0);
2782 if (ret)
2783 goto out;
2784 }
2785
2786 /*
2787 * wait for ordered IO before we have any locks. We'll loop again
2788 * below with the locks held.
2789 */
2790 ret = btrfs_wait_ordered_range(inode, alloc_start,
2791 alloc_end - alloc_start);
2792 if (ret)
2793 goto out;
2794
2795 locked_end = alloc_end - 1;
2796 while (1) {
2797 struct btrfs_ordered_extent *ordered;
2798
2799 /* the extent lock is ordered inside the running
2800 * transaction
2801 */
2802 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
2803 locked_end, &cached_state);
2804 ordered = btrfs_lookup_first_ordered_extent(inode,
2805 alloc_end - 1);
2806 if (ordered &&
2807 ordered->file_offset + ordered->len > alloc_start &&
2808 ordered->file_offset < alloc_end) {
2809 btrfs_put_ordered_extent(ordered);
2810 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
2811 alloc_start, locked_end,
2812 &cached_state, GFP_KERNEL);
2813 /*
2814 * we can't wait on the range with the transaction
2815 * running or with the extent lock held
2816 */
2817 ret = btrfs_wait_ordered_range(inode, alloc_start,
2818 alloc_end - alloc_start);
2819 if (ret)
2820 goto out;
2821 } else {
2822 if (ordered)
2823 btrfs_put_ordered_extent(ordered);
2824 break;
2825 }
2826 }
2827
2828 /* First, check if we exceed the qgroup limit */
2829 INIT_LIST_HEAD(&reserve_list);
2830 while (1) {
2831 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
2832 alloc_end - cur_offset, 0);
2833 if (IS_ERR_OR_NULL(em)) {
2834 if (!em)
2835 ret = -ENOMEM;
2836 else
2837 ret = PTR_ERR(em);
2838 break;
2839 }
2840 last_byte = min(extent_map_end(em), alloc_end);
2841 actual_end = min_t(u64, extent_map_end(em), offset + len);
2842 last_byte = ALIGN(last_byte, blocksize);
2843 if (em->block_start == EXTENT_MAP_HOLE ||
2844 (cur_offset >= inode->i_size &&
2845 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
2846 ret = add_falloc_range(&reserve_list, cur_offset,
2847 last_byte - cur_offset);
2848 if (ret < 0) {
2849 free_extent_map(em);
2850 break;
2851 }
2852 ret = btrfs_qgroup_reserve_data(inode, cur_offset,
2853 last_byte - cur_offset);
2854 if (ret < 0)
2855 break;
2856 } else {
2857 /*
2858 * Do not need to reserve unwritten extent for this
2859 * range, free reserved data space first, otherwise
2860 * it'll result in false ENOSPC error.
2861 */
2862 btrfs_free_reserved_data_space(inode, cur_offset,
2863 last_byte - cur_offset);
2864 }
2865 free_extent_map(em);
2866 cur_offset = last_byte;
2867 if (cur_offset >= alloc_end)
2868 break;
2869 }
2870
2871 /*
2872 * If ret is still 0, means we're OK to fallocate.
2873 * Or just cleanup the list and exit.
2874 */
2875 list_for_each_entry_safe(range, tmp, &reserve_list, list) {
2876 if (!ret)
2877 ret = btrfs_prealloc_file_range(inode, mode,
2878 range->start,
2879 range->len, 1 << inode->i_blkbits,
2880 offset + len, &alloc_hint);
2881 else
2882 btrfs_free_reserved_data_space(inode, range->start,
2883 range->len);
2884 list_del(&range->list);
2885 kfree(range);
2886 }
2887 if (ret < 0)
2888 goto out_unlock;
2889
2890 if (actual_end > inode->i_size &&
2891 !(mode & FALLOC_FL_KEEP_SIZE)) {
2892 struct btrfs_trans_handle *trans;
2893 struct btrfs_root *root = BTRFS_I(inode)->root;
2894
2895 /*
2896 * We didn't need to allocate any more space, but we
2897 * still extended the size of the file so we need to
2898 * update i_size and the inode item.
2899 */
2900 trans = btrfs_start_transaction(root, 1);
2901 if (IS_ERR(trans)) {
2902 ret = PTR_ERR(trans);
2903 } else {
2904 inode->i_ctime = current_time(inode);
2905 i_size_write(inode, actual_end);
2906 btrfs_ordered_update_i_size(inode, actual_end, NULL);
2907 ret = btrfs_update_inode(trans, root, inode);
2908 if (ret)
2909 btrfs_end_transaction(trans);
2910 else
2911 ret = btrfs_end_transaction(trans);
2912 }
2913 }
2914out_unlock:
2915 unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
2916 &cached_state, GFP_KERNEL);
2917out:
2918 inode_unlock(inode);
2919 /* Let go of our reservation. */
2920 if (ret != 0)
2921 btrfs_free_reserved_data_space(inode, alloc_start,
2922 alloc_end - cur_offset);
2923 return ret;
2924}
2925
2926static int find_desired_extent(struct inode *inode, loff_t *offset, int whence)
2927{
2928 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2929 struct extent_map *em = NULL;
2930 struct extent_state *cached_state = NULL;
2931 u64 lockstart;
2932 u64 lockend;
2933 u64 start;
2934 u64 len;
2935 int ret = 0;
2936
2937 if (inode->i_size == 0)
2938 return -ENXIO;
2939
2940 /*
2941 * *offset can be negative, in this case we start finding DATA/HOLE from
2942 * the very start of the file.
2943 */
2944 start = max_t(loff_t, 0, *offset);
2945
2946 lockstart = round_down(start, fs_info->sectorsize);
2947 lockend = round_up(i_size_read(inode),
2948 fs_info->sectorsize);
2949 if (lockend <= lockstart)
2950 lockend = lockstart + fs_info->sectorsize;
2951 lockend--;
2952 len = lockend - lockstart + 1;
2953
2954 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2955 &cached_state);
2956
2957 while (start < inode->i_size) {
2958 em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
2959 if (IS_ERR(em)) {
2960 ret = PTR_ERR(em);
2961 em = NULL;
2962 break;
2963 }
2964
2965 if (whence == SEEK_HOLE &&
2966 (em->block_start == EXTENT_MAP_HOLE ||
2967 test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
2968 break;
2969 else if (whence == SEEK_DATA &&
2970 (em->block_start != EXTENT_MAP_HOLE &&
2971 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
2972 break;
2973
2974 start = em->start + em->len;
2975 free_extent_map(em);
2976 em = NULL;
2977 cond_resched();
2978 }
2979 free_extent_map(em);
2980 if (!ret) {
2981 if (whence == SEEK_DATA && start >= inode->i_size)
2982 ret = -ENXIO;
2983 else
2984 *offset = min_t(loff_t, start, inode->i_size);
2985 }
2986 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2987 &cached_state, GFP_NOFS);
2988 return ret;
2989}
2990
2991static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
2992{
2993 struct inode *inode = file->f_mapping->host;
2994 int ret;
2995
2996 inode_lock(inode);
2997 switch (whence) {
2998 case SEEK_END:
2999 case SEEK_CUR:
3000 offset = generic_file_llseek(file, offset, whence);
3001 goto out;
3002 case SEEK_DATA:
3003 case SEEK_HOLE:
3004 if (offset >= i_size_read(inode)) {
3005 inode_unlock(inode);
3006 return -ENXIO;
3007 }
3008
3009 ret = find_desired_extent(inode, &offset, whence);
3010 if (ret) {
3011 inode_unlock(inode);
3012 return ret;
3013 }
3014 }
3015
3016 offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
3017out:
3018 inode_unlock(inode);
3019 return offset;
3020}
3021
3022const struct file_operations btrfs_file_operations = {
3023 .llseek = btrfs_file_llseek,
3024 .read_iter = generic_file_read_iter,
3025 .splice_read = generic_file_splice_read,
3026 .write_iter = btrfs_file_write_iter,
3027 .mmap = btrfs_file_mmap,
3028 .open = generic_file_open,
3029 .release = btrfs_release_file,
3030 .fsync = btrfs_sync_file,
3031 .fallocate = btrfs_fallocate,
3032 .unlocked_ioctl = btrfs_ioctl,
3033#ifdef CONFIG_COMPAT
3034 .compat_ioctl = btrfs_compat_ioctl,
3035#endif
3036 .clone_file_range = btrfs_clone_file_range,
3037 .dedupe_file_range = btrfs_dedupe_file_range,
3038};
3039
3040void btrfs_auto_defrag_exit(void)
3041{
3042 kmem_cache_destroy(btrfs_inode_defrag_cachep);
3043}
3044
3045int btrfs_auto_defrag_init(void)
3046{
3047 btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
3048 sizeof(struct inode_defrag), 0,
3049 SLAB_MEM_SPREAD,
3050 NULL);
3051 if (!btrfs_inode_defrag_cachep)
3052 return -ENOMEM;
3053
3054 return 0;
3055}
3056
3057int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end)
3058{
3059 int ret;
3060
3061 /*
3062 * So with compression we will find and lock a dirty page and clear the
3063 * first one as dirty, setup an async extent, and immediately return
3064 * with the entire range locked but with nobody actually marked with
3065 * writeback. So we can't just filemap_write_and_wait_range() and
3066 * expect it to work since it will just kick off a thread to do the
3067 * actual work. So we need to call filemap_fdatawrite_range _again_
3068 * since it will wait on the page lock, which won't be unlocked until
3069 * after the pages have been marked as writeback and so we're good to go
3070 * from there. We have to do this otherwise we'll miss the ordered
3071 * extents and that results in badness. Please Josef, do not think you
3072 * know better and pull this out at some point in the future, it is
3073 * right and you are wrong.
3074 */
3075 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
3076 if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
3077 &BTRFS_I(inode)->runtime_flags))
3078 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
3079
3080 return ret;
3081}
1/*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/fs.h>
20#include <linux/pagemap.h>
21#include <linux/highmem.h>
22#include <linux/time.h>
23#include <linux/init.h>
24#include <linux/string.h>
25#include <linux/backing-dev.h>
26#include <linux/mpage.h>
27#include <linux/aio.h>
28#include <linux/falloc.h>
29#include <linux/swap.h>
30#include <linux/writeback.h>
31#include <linux/statfs.h>
32#include <linux/compat.h>
33#include <linux/slab.h>
34#include <linux/btrfs.h>
35#include "ctree.h"
36#include "disk-io.h"
37#include "transaction.h"
38#include "btrfs_inode.h"
39#include "print-tree.h"
40#include "tree-log.h"
41#include "locking.h"
42#include "volumes.h"
43
44static struct kmem_cache *btrfs_inode_defrag_cachep;
45/*
46 * when auto defrag is enabled we
47 * queue up these defrag structs to remember which
48 * inodes need defragging passes
49 */
50struct inode_defrag {
51 struct rb_node rb_node;
52 /* objectid */
53 u64 ino;
54 /*
55 * transid where the defrag was added, we search for
56 * extents newer than this
57 */
58 u64 transid;
59
60 /* root objectid */
61 u64 root;
62
63 /* last offset we were able to defrag */
64 u64 last_offset;
65
66 /* if we've wrapped around back to zero once already */
67 int cycled;
68};
69
70static int __compare_inode_defrag(struct inode_defrag *defrag1,
71 struct inode_defrag *defrag2)
72{
73 if (defrag1->root > defrag2->root)
74 return 1;
75 else if (defrag1->root < defrag2->root)
76 return -1;
77 else if (defrag1->ino > defrag2->ino)
78 return 1;
79 else if (defrag1->ino < defrag2->ino)
80 return -1;
81 else
82 return 0;
83}
84
85/* pop a record for an inode into the defrag tree. The lock
86 * must be held already
87 *
88 * If you're inserting a record for an older transid than an
89 * existing record, the transid already in the tree is lowered
90 *
91 * If an existing record is found the defrag item you
92 * pass in is freed
93 */
94static int __btrfs_add_inode_defrag(struct inode *inode,
95 struct inode_defrag *defrag)
96{
97 struct btrfs_root *root = BTRFS_I(inode)->root;
98 struct inode_defrag *entry;
99 struct rb_node **p;
100 struct rb_node *parent = NULL;
101 int ret;
102
103 p = &root->fs_info->defrag_inodes.rb_node;
104 while (*p) {
105 parent = *p;
106 entry = rb_entry(parent, struct inode_defrag, rb_node);
107
108 ret = __compare_inode_defrag(defrag, entry);
109 if (ret < 0)
110 p = &parent->rb_left;
111 else if (ret > 0)
112 p = &parent->rb_right;
113 else {
114 /* if we're reinserting an entry for
115 * an old defrag run, make sure to
116 * lower the transid of our existing record
117 */
118 if (defrag->transid < entry->transid)
119 entry->transid = defrag->transid;
120 if (defrag->last_offset > entry->last_offset)
121 entry->last_offset = defrag->last_offset;
122 return -EEXIST;
123 }
124 }
125 set_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
126 rb_link_node(&defrag->rb_node, parent, p);
127 rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes);
128 return 0;
129}
130
131static inline int __need_auto_defrag(struct btrfs_root *root)
132{
133 if (!btrfs_test_opt(root, AUTO_DEFRAG))
134 return 0;
135
136 if (btrfs_fs_closing(root->fs_info))
137 return 0;
138
139 return 1;
140}
141
142/*
143 * insert a defrag record for this inode if auto defrag is
144 * enabled
145 */
146int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
147 struct inode *inode)
148{
149 struct btrfs_root *root = BTRFS_I(inode)->root;
150 struct inode_defrag *defrag;
151 u64 transid;
152 int ret;
153
154 if (!__need_auto_defrag(root))
155 return 0;
156
157 if (test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags))
158 return 0;
159
160 if (trans)
161 transid = trans->transid;
162 else
163 transid = BTRFS_I(inode)->root->last_trans;
164
165 defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS);
166 if (!defrag)
167 return -ENOMEM;
168
169 defrag->ino = btrfs_ino(inode);
170 defrag->transid = transid;
171 defrag->root = root->root_key.objectid;
172
173 spin_lock(&root->fs_info->defrag_inodes_lock);
174 if (!test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags)) {
175 /*
176 * If we set IN_DEFRAG flag and evict the inode from memory,
177 * and then re-read this inode, this new inode doesn't have
178 * IN_DEFRAG flag. At the case, we may find the existed defrag.
179 */
180 ret = __btrfs_add_inode_defrag(inode, defrag);
181 if (ret)
182 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
183 } else {
184 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
185 }
186 spin_unlock(&root->fs_info->defrag_inodes_lock);
187 return 0;
188}
189
190/*
191 * Requeue the defrag object. If there is a defrag object that points to
192 * the same inode in the tree, we will merge them together (by
193 * __btrfs_add_inode_defrag()) and free the one that we want to requeue.
194 */
195static void btrfs_requeue_inode_defrag(struct inode *inode,
196 struct inode_defrag *defrag)
197{
198 struct btrfs_root *root = BTRFS_I(inode)->root;
199 int ret;
200
201 if (!__need_auto_defrag(root))
202 goto out;
203
204 /*
205 * Here we don't check the IN_DEFRAG flag, because we need merge
206 * them together.
207 */
208 spin_lock(&root->fs_info->defrag_inodes_lock);
209 ret = __btrfs_add_inode_defrag(inode, defrag);
210 spin_unlock(&root->fs_info->defrag_inodes_lock);
211 if (ret)
212 goto out;
213 return;
214out:
215 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
216}
217
218/*
219 * pick the defragable inode that we want, if it doesn't exist, we will get
220 * the next one.
221 */
222static struct inode_defrag *
223btrfs_pick_defrag_inode(struct btrfs_fs_info *fs_info, u64 root, u64 ino)
224{
225 struct inode_defrag *entry = NULL;
226 struct inode_defrag tmp;
227 struct rb_node *p;
228 struct rb_node *parent = NULL;
229 int ret;
230
231 tmp.ino = ino;
232 tmp.root = root;
233
234 spin_lock(&fs_info->defrag_inodes_lock);
235 p = fs_info->defrag_inodes.rb_node;
236 while (p) {
237 parent = p;
238 entry = rb_entry(parent, struct inode_defrag, rb_node);
239
240 ret = __compare_inode_defrag(&tmp, entry);
241 if (ret < 0)
242 p = parent->rb_left;
243 else if (ret > 0)
244 p = parent->rb_right;
245 else
246 goto out;
247 }
248
249 if (parent && __compare_inode_defrag(&tmp, entry) > 0) {
250 parent = rb_next(parent);
251 if (parent)
252 entry = rb_entry(parent, struct inode_defrag, rb_node);
253 else
254 entry = NULL;
255 }
256out:
257 if (entry)
258 rb_erase(parent, &fs_info->defrag_inodes);
259 spin_unlock(&fs_info->defrag_inodes_lock);
260 return entry;
261}
262
263void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info)
264{
265 struct inode_defrag *defrag;
266 struct rb_node *node;
267
268 spin_lock(&fs_info->defrag_inodes_lock);
269 node = rb_first(&fs_info->defrag_inodes);
270 while (node) {
271 rb_erase(node, &fs_info->defrag_inodes);
272 defrag = rb_entry(node, struct inode_defrag, rb_node);
273 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
274
275 if (need_resched()) {
276 spin_unlock(&fs_info->defrag_inodes_lock);
277 cond_resched();
278 spin_lock(&fs_info->defrag_inodes_lock);
279 }
280
281 node = rb_first(&fs_info->defrag_inodes);
282 }
283 spin_unlock(&fs_info->defrag_inodes_lock);
284}
285
286#define BTRFS_DEFRAG_BATCH 1024
287
288static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
289 struct inode_defrag *defrag)
290{
291 struct btrfs_root *inode_root;
292 struct inode *inode;
293 struct btrfs_key key;
294 struct btrfs_ioctl_defrag_range_args range;
295 int num_defrag;
296 int index;
297 int ret;
298
299 /* get the inode */
300 key.objectid = defrag->root;
301 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
302 key.offset = (u64)-1;
303
304 index = srcu_read_lock(&fs_info->subvol_srcu);
305
306 inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
307 if (IS_ERR(inode_root)) {
308 ret = PTR_ERR(inode_root);
309 goto cleanup;
310 }
311
312 key.objectid = defrag->ino;
313 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
314 key.offset = 0;
315 inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
316 if (IS_ERR(inode)) {
317 ret = PTR_ERR(inode);
318 goto cleanup;
319 }
320 srcu_read_unlock(&fs_info->subvol_srcu, index);
321
322 /* do a chunk of defrag */
323 clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
324 memset(&range, 0, sizeof(range));
325 range.len = (u64)-1;
326 range.start = defrag->last_offset;
327
328 sb_start_write(fs_info->sb);
329 num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
330 BTRFS_DEFRAG_BATCH);
331 sb_end_write(fs_info->sb);
332 /*
333 * if we filled the whole defrag batch, there
334 * must be more work to do. Queue this defrag
335 * again
336 */
337 if (num_defrag == BTRFS_DEFRAG_BATCH) {
338 defrag->last_offset = range.start;
339 btrfs_requeue_inode_defrag(inode, defrag);
340 } else if (defrag->last_offset && !defrag->cycled) {
341 /*
342 * we didn't fill our defrag batch, but
343 * we didn't start at zero. Make sure we loop
344 * around to the start of the file.
345 */
346 defrag->last_offset = 0;
347 defrag->cycled = 1;
348 btrfs_requeue_inode_defrag(inode, defrag);
349 } else {
350 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
351 }
352
353 iput(inode);
354 return 0;
355cleanup:
356 srcu_read_unlock(&fs_info->subvol_srcu, index);
357 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
358 return ret;
359}
360
361/*
362 * run through the list of inodes in the FS that need
363 * defragging
364 */
365int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
366{
367 struct inode_defrag *defrag;
368 u64 first_ino = 0;
369 u64 root_objectid = 0;
370
371 atomic_inc(&fs_info->defrag_running);
372 while (1) {
373 /* Pause the auto defragger. */
374 if (test_bit(BTRFS_FS_STATE_REMOUNTING,
375 &fs_info->fs_state))
376 break;
377
378 if (!__need_auto_defrag(fs_info->tree_root))
379 break;
380
381 /* find an inode to defrag */
382 defrag = btrfs_pick_defrag_inode(fs_info, root_objectid,
383 first_ino);
384 if (!defrag) {
385 if (root_objectid || first_ino) {
386 root_objectid = 0;
387 first_ino = 0;
388 continue;
389 } else {
390 break;
391 }
392 }
393
394 first_ino = defrag->ino + 1;
395 root_objectid = defrag->root;
396
397 __btrfs_run_defrag_inode(fs_info, defrag);
398 }
399 atomic_dec(&fs_info->defrag_running);
400
401 /*
402 * during unmount, we use the transaction_wait queue to
403 * wait for the defragger to stop
404 */
405 wake_up(&fs_info->transaction_wait);
406 return 0;
407}
408
409/* simple helper to fault in pages and copy. This should go away
410 * and be replaced with calls into generic code.
411 */
412static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
413 size_t write_bytes,
414 struct page **prepared_pages,
415 struct iov_iter *i)
416{
417 size_t copied = 0;
418 size_t total_copied = 0;
419 int pg = 0;
420 int offset = pos & (PAGE_CACHE_SIZE - 1);
421
422 while (write_bytes > 0) {
423 size_t count = min_t(size_t,
424 PAGE_CACHE_SIZE - offset, write_bytes);
425 struct page *page = prepared_pages[pg];
426 /*
427 * Copy data from userspace to the current page
428 */
429 copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
430
431 /* Flush processor's dcache for this page */
432 flush_dcache_page(page);
433
434 /*
435 * if we get a partial write, we can end up with
436 * partially up to date pages. These add
437 * a lot of complexity, so make sure they don't
438 * happen by forcing this copy to be retried.
439 *
440 * The rest of the btrfs_file_write code will fall
441 * back to page at a time copies after we return 0.
442 */
443 if (!PageUptodate(page) && copied < count)
444 copied = 0;
445
446 iov_iter_advance(i, copied);
447 write_bytes -= copied;
448 total_copied += copied;
449
450 /* Return to btrfs_file_aio_write to fault page */
451 if (unlikely(copied == 0))
452 break;
453
454 if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
455 offset += copied;
456 } else {
457 pg++;
458 offset = 0;
459 }
460 }
461 return total_copied;
462}
463
464/*
465 * unlocks pages after btrfs_file_write is done with them
466 */
467static void btrfs_drop_pages(struct page **pages, size_t num_pages)
468{
469 size_t i;
470 for (i = 0; i < num_pages; i++) {
471 /* page checked is some magic around finding pages that
472 * have been modified without going through btrfs_set_page_dirty
473 * clear it here
474 */
475 ClearPageChecked(pages[i]);
476 unlock_page(pages[i]);
477 mark_page_accessed(pages[i]);
478 page_cache_release(pages[i]);
479 }
480}
481
482/*
483 * after copy_from_user, pages need to be dirtied and we need to make
484 * sure holes are created between the current EOF and the start of
485 * any next extents (if required).
486 *
487 * this also makes the decision about creating an inline extent vs
488 * doing real data extents, marking pages dirty and delalloc as required.
489 */
490int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
491 struct page **pages, size_t num_pages,
492 loff_t pos, size_t write_bytes,
493 struct extent_state **cached)
494{
495 int err = 0;
496 int i;
497 u64 num_bytes;
498 u64 start_pos;
499 u64 end_of_last_block;
500 u64 end_pos = pos + write_bytes;
501 loff_t isize = i_size_read(inode);
502
503 start_pos = pos & ~((u64)root->sectorsize - 1);
504 num_bytes = ALIGN(write_bytes + pos - start_pos, root->sectorsize);
505
506 end_of_last_block = start_pos + num_bytes - 1;
507 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
508 cached);
509 if (err)
510 return err;
511
512 for (i = 0; i < num_pages; i++) {
513 struct page *p = pages[i];
514 SetPageUptodate(p);
515 ClearPageChecked(p);
516 set_page_dirty(p);
517 }
518
519 /*
520 * we've only changed i_size in ram, and we haven't updated
521 * the disk i_size. There is no need to log the inode
522 * at this time.
523 */
524 if (end_pos > isize)
525 i_size_write(inode, end_pos);
526 return 0;
527}
528
529/*
530 * this drops all the extents in the cache that intersect the range
531 * [start, end]. Existing extents are split as required.
532 */
533void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
534 int skip_pinned)
535{
536 struct extent_map *em;
537 struct extent_map *split = NULL;
538 struct extent_map *split2 = NULL;
539 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
540 u64 len = end - start + 1;
541 u64 gen;
542 int ret;
543 int testend = 1;
544 unsigned long flags;
545 int compressed = 0;
546 bool modified;
547
548 WARN_ON(end < start);
549 if (end == (u64)-1) {
550 len = (u64)-1;
551 testend = 0;
552 }
553 while (1) {
554 int no_splits = 0;
555
556 modified = false;
557 if (!split)
558 split = alloc_extent_map();
559 if (!split2)
560 split2 = alloc_extent_map();
561 if (!split || !split2)
562 no_splits = 1;
563
564 write_lock(&em_tree->lock);
565 em = lookup_extent_mapping(em_tree, start, len);
566 if (!em) {
567 write_unlock(&em_tree->lock);
568 break;
569 }
570 flags = em->flags;
571 gen = em->generation;
572 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
573 if (testend && em->start + em->len >= start + len) {
574 free_extent_map(em);
575 write_unlock(&em_tree->lock);
576 break;
577 }
578 start = em->start + em->len;
579 if (testend)
580 len = start + len - (em->start + em->len);
581 free_extent_map(em);
582 write_unlock(&em_tree->lock);
583 continue;
584 }
585 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
586 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
587 clear_bit(EXTENT_FLAG_LOGGING, &flags);
588 modified = !list_empty(&em->list);
589 if (no_splits)
590 goto next;
591
592 if (em->start < start) {
593 split->start = em->start;
594 split->len = start - em->start;
595
596 if (em->block_start < EXTENT_MAP_LAST_BYTE) {
597 split->orig_start = em->orig_start;
598 split->block_start = em->block_start;
599
600 if (compressed)
601 split->block_len = em->block_len;
602 else
603 split->block_len = split->len;
604 split->orig_block_len = max(split->block_len,
605 em->orig_block_len);
606 split->ram_bytes = em->ram_bytes;
607 } else {
608 split->orig_start = split->start;
609 split->block_len = 0;
610 split->block_start = em->block_start;
611 split->orig_block_len = 0;
612 split->ram_bytes = split->len;
613 }
614
615 split->generation = gen;
616 split->bdev = em->bdev;
617 split->flags = flags;
618 split->compress_type = em->compress_type;
619 replace_extent_mapping(em_tree, em, split, modified);
620 free_extent_map(split);
621 split = split2;
622 split2 = NULL;
623 }
624 if (testend && em->start + em->len > start + len) {
625 u64 diff = start + len - em->start;
626
627 split->start = start + len;
628 split->len = em->start + em->len - (start + len);
629 split->bdev = em->bdev;
630 split->flags = flags;
631 split->compress_type = em->compress_type;
632 split->generation = gen;
633
634 if (em->block_start < EXTENT_MAP_LAST_BYTE) {
635 split->orig_block_len = max(em->block_len,
636 em->orig_block_len);
637
638 split->ram_bytes = em->ram_bytes;
639 if (compressed) {
640 split->block_len = em->block_len;
641 split->block_start = em->block_start;
642 split->orig_start = em->orig_start;
643 } else {
644 split->block_len = split->len;
645 split->block_start = em->block_start
646 + diff;
647 split->orig_start = em->orig_start;
648 }
649 } else {
650 split->ram_bytes = split->len;
651 split->orig_start = split->start;
652 split->block_len = 0;
653 split->block_start = em->block_start;
654 split->orig_block_len = 0;
655 }
656
657 if (extent_map_in_tree(em)) {
658 replace_extent_mapping(em_tree, em, split,
659 modified);
660 } else {
661 ret = add_extent_mapping(em_tree, split,
662 modified);
663 ASSERT(ret == 0); /* Logic error */
664 }
665 free_extent_map(split);
666 split = NULL;
667 }
668next:
669 if (extent_map_in_tree(em))
670 remove_extent_mapping(em_tree, em);
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 */
693int __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 int replace_extent,
698 u32 extent_item_size,
699 int *key_inserted)
700{
701 struct extent_buffer *leaf;
702 struct btrfs_file_extent_item *fi;
703 struct btrfs_key key;
704 struct btrfs_key new_key;
705 u64 ino = btrfs_ino(inode);
706 u64 search_start = start;
707 u64 disk_bytenr = 0;
708 u64 num_bytes = 0;
709 u64 extent_offset = 0;
710 u64 extent_end = 0;
711 int del_nr = 0;
712 int del_slot = 0;
713 int extent_type;
714 int recow;
715 int ret;
716 int modify_tree = -1;
717 int update_refs = (root->ref_cows || root == root->fs_info->tree_root);
718 int found = 0;
719 int leafs_visited = 0;
720
721 if (drop_cache)
722 btrfs_drop_extent_cache(inode, start, end - 1, 0);
723
724 if (start >= BTRFS_I(inode)->disk_i_size && !replace_extent)
725 modify_tree = 0;
726
727 while (1) {
728 recow = 0;
729 ret = btrfs_lookup_file_extent(trans, root, path, ino,
730 search_start, modify_tree);
731 if (ret < 0)
732 break;
733 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
734 leaf = path->nodes[0];
735 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
736 if (key.objectid == ino &&
737 key.type == BTRFS_EXTENT_DATA_KEY)
738 path->slots[0]--;
739 }
740 ret = 0;
741 leafs_visited++;
742next_slot:
743 leaf = path->nodes[0];
744 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
745 BUG_ON(del_nr > 0);
746 ret = btrfs_next_leaf(root, path);
747 if (ret < 0)
748 break;
749 if (ret > 0) {
750 ret = 0;
751 break;
752 }
753 leafs_visited++;
754 leaf = path->nodes[0];
755 recow = 1;
756 }
757
758 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
759 if (key.objectid > ino ||
760 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
761 break;
762
763 fi = btrfs_item_ptr(leaf, path->slots[0],
764 struct btrfs_file_extent_item);
765 extent_type = btrfs_file_extent_type(leaf, fi);
766
767 if (extent_type == BTRFS_FILE_EXTENT_REG ||
768 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
769 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
770 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
771 extent_offset = btrfs_file_extent_offset(leaf, fi);
772 extent_end = key.offset +
773 btrfs_file_extent_num_bytes(leaf, fi);
774 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
775 extent_end = key.offset +
776 btrfs_file_extent_inline_len(leaf,
777 path->slots[0], fi);
778 } else {
779 WARN_ON(1);
780 extent_end = search_start;
781 }
782
783 if (extent_end <= search_start) {
784 path->slots[0]++;
785 goto next_slot;
786 }
787
788 found = 1;
789 search_start = max(key.offset, start);
790 if (recow || !modify_tree) {
791 modify_tree = -1;
792 btrfs_release_path(path);
793 continue;
794 }
795
796 /*
797 * | - range to drop - |
798 * | -------- extent -------- |
799 */
800 if (start > key.offset && end < extent_end) {
801 BUG_ON(del_nr > 0);
802 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
803 ret = -EOPNOTSUPP;
804 break;
805 }
806
807 memcpy(&new_key, &key, sizeof(new_key));
808 new_key.offset = start;
809 ret = btrfs_duplicate_item(trans, root, path,
810 &new_key);
811 if (ret == -EAGAIN) {
812 btrfs_release_path(path);
813 continue;
814 }
815 if (ret < 0)
816 break;
817
818 leaf = path->nodes[0];
819 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
820 struct btrfs_file_extent_item);
821 btrfs_set_file_extent_num_bytes(leaf, fi,
822 start - key.offset);
823
824 fi = btrfs_item_ptr(leaf, path->slots[0],
825 struct btrfs_file_extent_item);
826
827 extent_offset += start - key.offset;
828 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
829 btrfs_set_file_extent_num_bytes(leaf, fi,
830 extent_end - start);
831 btrfs_mark_buffer_dirty(leaf);
832
833 if (update_refs && disk_bytenr > 0) {
834 ret = btrfs_inc_extent_ref(trans, root,
835 disk_bytenr, num_bytes, 0,
836 root->root_key.objectid,
837 new_key.objectid,
838 start - extent_offset, 0);
839 BUG_ON(ret); /* -ENOMEM */
840 }
841 key.offset = start;
842 }
843 /*
844 * | ---- range to drop ----- |
845 * | -------- extent -------- |
846 */
847 if (start <= key.offset && end < extent_end) {
848 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
849 ret = -EOPNOTSUPP;
850 break;
851 }
852
853 memcpy(&new_key, &key, sizeof(new_key));
854 new_key.offset = end;
855 btrfs_set_item_key_safe(root, path, &new_key);
856
857 extent_offset += end - key.offset;
858 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
859 btrfs_set_file_extent_num_bytes(leaf, fi,
860 extent_end - end);
861 btrfs_mark_buffer_dirty(leaf);
862 if (update_refs && disk_bytenr > 0)
863 inode_sub_bytes(inode, end - key.offset);
864 break;
865 }
866
867 search_start = extent_end;
868 /*
869 * | ---- range to drop ----- |
870 * | -------- extent -------- |
871 */
872 if (start > key.offset && end >= extent_end) {
873 BUG_ON(del_nr > 0);
874 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
875 ret = -EOPNOTSUPP;
876 break;
877 }
878
879 btrfs_set_file_extent_num_bytes(leaf, fi,
880 start - key.offset);
881 btrfs_mark_buffer_dirty(leaf);
882 if (update_refs && disk_bytenr > 0)
883 inode_sub_bytes(inode, extent_end - start);
884 if (end == extent_end)
885 break;
886
887 path->slots[0]++;
888 goto next_slot;
889 }
890
891 /*
892 * | ---- range to drop ----- |
893 * | ------ extent ------ |
894 */
895 if (start <= key.offset && end >= extent_end) {
896 if (del_nr == 0) {
897 del_slot = path->slots[0];
898 del_nr = 1;
899 } else {
900 BUG_ON(del_slot + del_nr != path->slots[0]);
901 del_nr++;
902 }
903
904 if (update_refs &&
905 extent_type == BTRFS_FILE_EXTENT_INLINE) {
906 inode_sub_bytes(inode,
907 extent_end - key.offset);
908 extent_end = ALIGN(extent_end,
909 root->sectorsize);
910 } else if (update_refs && disk_bytenr > 0) {
911 ret = btrfs_free_extent(trans, root,
912 disk_bytenr, num_bytes, 0,
913 root->root_key.objectid,
914 key.objectid, key.offset -
915 extent_offset, 0);
916 BUG_ON(ret); /* -ENOMEM */
917 inode_sub_bytes(inode,
918 extent_end - key.offset);
919 }
920
921 if (end == extent_end)
922 break;
923
924 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
925 path->slots[0]++;
926 goto next_slot;
927 }
928
929 ret = btrfs_del_items(trans, root, path, del_slot,
930 del_nr);
931 if (ret) {
932 btrfs_abort_transaction(trans, root, ret);
933 break;
934 }
935
936 del_nr = 0;
937 del_slot = 0;
938
939 btrfs_release_path(path);
940 continue;
941 }
942
943 BUG_ON(1);
944 }
945
946 if (!ret && del_nr > 0) {
947 /*
948 * Set path->slots[0] to first slot, so that after the delete
949 * if items are move off from our leaf to its immediate left or
950 * right neighbor leafs, we end up with a correct and adjusted
951 * path->slots[0] for our insertion (if replace_extent != 0).
952 */
953 path->slots[0] = del_slot;
954 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
955 if (ret)
956 btrfs_abort_transaction(trans, root, ret);
957 }
958
959 leaf = path->nodes[0];
960 /*
961 * If btrfs_del_items() was called, it might have deleted a leaf, in
962 * which case it unlocked our path, so check path->locks[0] matches a
963 * write lock.
964 */
965 if (!ret && replace_extent && leafs_visited == 1 &&
966 (path->locks[0] == BTRFS_WRITE_LOCK_BLOCKING ||
967 path->locks[0] == BTRFS_WRITE_LOCK) &&
968 btrfs_leaf_free_space(root, leaf) >=
969 sizeof(struct btrfs_item) + extent_item_size) {
970
971 key.objectid = ino;
972 key.type = BTRFS_EXTENT_DATA_KEY;
973 key.offset = start;
974 if (!del_nr && path->slots[0] < btrfs_header_nritems(leaf)) {
975 struct btrfs_key slot_key;
976
977 btrfs_item_key_to_cpu(leaf, &slot_key, path->slots[0]);
978 if (btrfs_comp_cpu_keys(&key, &slot_key) > 0)
979 path->slots[0]++;
980 }
981 setup_items_for_insert(root, path, &key,
982 &extent_item_size,
983 extent_item_size,
984 sizeof(struct btrfs_item) +
985 extent_item_size, 1);
986 *key_inserted = 1;
987 }
988
989 if (!replace_extent || !(*key_inserted))
990 btrfs_release_path(path);
991 if (drop_end)
992 *drop_end = found ? min(end, extent_end) : end;
993 return ret;
994}
995
996int btrfs_drop_extents(struct btrfs_trans_handle *trans,
997 struct btrfs_root *root, struct inode *inode, u64 start,
998 u64 end, int drop_cache)
999{
1000 struct btrfs_path *path;
1001 int ret;
1002
1003 path = btrfs_alloc_path();
1004 if (!path)
1005 return -ENOMEM;
1006 ret = __btrfs_drop_extents(trans, root, inode, path, start, end, NULL,
1007 drop_cache, 0, 0, NULL);
1008 btrfs_free_path(path);
1009 return ret;
1010}
1011
1012static int extent_mergeable(struct extent_buffer *leaf, int slot,
1013 u64 objectid, u64 bytenr, u64 orig_offset,
1014 u64 *start, u64 *end)
1015{
1016 struct btrfs_file_extent_item *fi;
1017 struct btrfs_key key;
1018 u64 extent_end;
1019
1020 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
1021 return 0;
1022
1023 btrfs_item_key_to_cpu(leaf, &key, slot);
1024 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
1025 return 0;
1026
1027 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
1028 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
1029 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
1030 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
1031 btrfs_file_extent_compression(leaf, fi) ||
1032 btrfs_file_extent_encryption(leaf, fi) ||
1033 btrfs_file_extent_other_encoding(leaf, fi))
1034 return 0;
1035
1036 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1037 if ((*start && *start != key.offset) || (*end && *end != extent_end))
1038 return 0;
1039
1040 *start = key.offset;
1041 *end = extent_end;
1042 return 1;
1043}
1044
1045/*
1046 * Mark extent in the range start - end as written.
1047 *
1048 * This changes extent type from 'pre-allocated' to 'regular'. If only
1049 * part of extent is marked as written, the extent will be split into
1050 * two or three.
1051 */
1052int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
1053 struct inode *inode, u64 start, u64 end)
1054{
1055 struct btrfs_root *root = BTRFS_I(inode)->root;
1056 struct extent_buffer *leaf;
1057 struct btrfs_path *path;
1058 struct btrfs_file_extent_item *fi;
1059 struct btrfs_key key;
1060 struct btrfs_key new_key;
1061 u64 bytenr;
1062 u64 num_bytes;
1063 u64 extent_end;
1064 u64 orig_offset;
1065 u64 other_start;
1066 u64 other_end;
1067 u64 split;
1068 int del_nr = 0;
1069 int del_slot = 0;
1070 int recow;
1071 int ret;
1072 u64 ino = btrfs_ino(inode);
1073
1074 path = btrfs_alloc_path();
1075 if (!path)
1076 return -ENOMEM;
1077again:
1078 recow = 0;
1079 split = start;
1080 key.objectid = ino;
1081 key.type = BTRFS_EXTENT_DATA_KEY;
1082 key.offset = split;
1083
1084 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1085 if (ret < 0)
1086 goto out;
1087 if (ret > 0 && path->slots[0] > 0)
1088 path->slots[0]--;
1089
1090 leaf = path->nodes[0];
1091 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1092 BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
1093 fi = btrfs_item_ptr(leaf, path->slots[0],
1094 struct btrfs_file_extent_item);
1095 BUG_ON(btrfs_file_extent_type(leaf, fi) !=
1096 BTRFS_FILE_EXTENT_PREALLOC);
1097 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1098 BUG_ON(key.offset > start || extent_end < end);
1099
1100 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1101 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1102 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
1103 memcpy(&new_key, &key, sizeof(new_key));
1104
1105 if (start == key.offset && end < extent_end) {
1106 other_start = 0;
1107 other_end = start;
1108 if (extent_mergeable(leaf, path->slots[0] - 1,
1109 ino, bytenr, orig_offset,
1110 &other_start, &other_end)) {
1111 new_key.offset = end;
1112 btrfs_set_item_key_safe(root, path, &new_key);
1113 fi = btrfs_item_ptr(leaf, path->slots[0],
1114 struct btrfs_file_extent_item);
1115 btrfs_set_file_extent_generation(leaf, fi,
1116 trans->transid);
1117 btrfs_set_file_extent_num_bytes(leaf, fi,
1118 extent_end - end);
1119 btrfs_set_file_extent_offset(leaf, fi,
1120 end - orig_offset);
1121 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1122 struct btrfs_file_extent_item);
1123 btrfs_set_file_extent_generation(leaf, fi,
1124 trans->transid);
1125 btrfs_set_file_extent_num_bytes(leaf, fi,
1126 end - other_start);
1127 btrfs_mark_buffer_dirty(leaf);
1128 goto out;
1129 }
1130 }
1131
1132 if (start > key.offset && end == extent_end) {
1133 other_start = end;
1134 other_end = 0;
1135 if (extent_mergeable(leaf, path->slots[0] + 1,
1136 ino, bytenr, orig_offset,
1137 &other_start, &other_end)) {
1138 fi = btrfs_item_ptr(leaf, path->slots[0],
1139 struct btrfs_file_extent_item);
1140 btrfs_set_file_extent_num_bytes(leaf, fi,
1141 start - key.offset);
1142 btrfs_set_file_extent_generation(leaf, fi,
1143 trans->transid);
1144 path->slots[0]++;
1145 new_key.offset = start;
1146 btrfs_set_item_key_safe(root, path, &new_key);
1147
1148 fi = btrfs_item_ptr(leaf, path->slots[0],
1149 struct btrfs_file_extent_item);
1150 btrfs_set_file_extent_generation(leaf, fi,
1151 trans->transid);
1152 btrfs_set_file_extent_num_bytes(leaf, fi,
1153 other_end - start);
1154 btrfs_set_file_extent_offset(leaf, fi,
1155 start - orig_offset);
1156 btrfs_mark_buffer_dirty(leaf);
1157 goto out;
1158 }
1159 }
1160
1161 while (start > key.offset || end < extent_end) {
1162 if (key.offset == start)
1163 split = end;
1164
1165 new_key.offset = split;
1166 ret = btrfs_duplicate_item(trans, root, path, &new_key);
1167 if (ret == -EAGAIN) {
1168 btrfs_release_path(path);
1169 goto again;
1170 }
1171 if (ret < 0) {
1172 btrfs_abort_transaction(trans, root, ret);
1173 goto out;
1174 }
1175
1176 leaf = path->nodes[0];
1177 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1178 struct btrfs_file_extent_item);
1179 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1180 btrfs_set_file_extent_num_bytes(leaf, fi,
1181 split - key.offset);
1182
1183 fi = btrfs_item_ptr(leaf, path->slots[0],
1184 struct btrfs_file_extent_item);
1185
1186 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1187 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
1188 btrfs_set_file_extent_num_bytes(leaf, fi,
1189 extent_end - split);
1190 btrfs_mark_buffer_dirty(leaf);
1191
1192 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
1193 root->root_key.objectid,
1194 ino, orig_offset, 0);
1195 BUG_ON(ret); /* -ENOMEM */
1196
1197 if (split == start) {
1198 key.offset = start;
1199 } else {
1200 BUG_ON(start != key.offset);
1201 path->slots[0]--;
1202 extent_end = end;
1203 }
1204 recow = 1;
1205 }
1206
1207 other_start = end;
1208 other_end = 0;
1209 if (extent_mergeable(leaf, path->slots[0] + 1,
1210 ino, bytenr, orig_offset,
1211 &other_start, &other_end)) {
1212 if (recow) {
1213 btrfs_release_path(path);
1214 goto again;
1215 }
1216 extent_end = other_end;
1217 del_slot = path->slots[0] + 1;
1218 del_nr++;
1219 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1220 0, root->root_key.objectid,
1221 ino, orig_offset, 0);
1222 BUG_ON(ret); /* -ENOMEM */
1223 }
1224 other_start = 0;
1225 other_end = start;
1226 if (extent_mergeable(leaf, path->slots[0] - 1,
1227 ino, bytenr, orig_offset,
1228 &other_start, &other_end)) {
1229 if (recow) {
1230 btrfs_release_path(path);
1231 goto again;
1232 }
1233 key.offset = other_start;
1234 del_slot = path->slots[0];
1235 del_nr++;
1236 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1237 0, root->root_key.objectid,
1238 ino, orig_offset, 0);
1239 BUG_ON(ret); /* -ENOMEM */
1240 }
1241 if (del_nr == 0) {
1242 fi = btrfs_item_ptr(leaf, path->slots[0],
1243 struct btrfs_file_extent_item);
1244 btrfs_set_file_extent_type(leaf, fi,
1245 BTRFS_FILE_EXTENT_REG);
1246 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1247 btrfs_mark_buffer_dirty(leaf);
1248 } else {
1249 fi = btrfs_item_ptr(leaf, del_slot - 1,
1250 struct btrfs_file_extent_item);
1251 btrfs_set_file_extent_type(leaf, fi,
1252 BTRFS_FILE_EXTENT_REG);
1253 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1254 btrfs_set_file_extent_num_bytes(leaf, fi,
1255 extent_end - key.offset);
1256 btrfs_mark_buffer_dirty(leaf);
1257
1258 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1259 if (ret < 0) {
1260 btrfs_abort_transaction(trans, root, ret);
1261 goto out;
1262 }
1263 }
1264out:
1265 btrfs_free_path(path);
1266 return 0;
1267}
1268
1269/*
1270 * on error we return an unlocked page and the error value
1271 * on success we return a locked page and 0
1272 */
1273static int prepare_uptodate_page(struct page *page, u64 pos,
1274 bool force_uptodate)
1275{
1276 int ret = 0;
1277
1278 if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) &&
1279 !PageUptodate(page)) {
1280 ret = btrfs_readpage(NULL, page);
1281 if (ret)
1282 return ret;
1283 lock_page(page);
1284 if (!PageUptodate(page)) {
1285 unlock_page(page);
1286 return -EIO;
1287 }
1288 }
1289 return 0;
1290}
1291
1292/*
1293 * this just gets pages into the page cache and locks them down.
1294 */
1295static noinline int prepare_pages(struct inode *inode, struct page **pages,
1296 size_t num_pages, loff_t pos,
1297 size_t write_bytes, bool force_uptodate)
1298{
1299 int i;
1300 unsigned long index = pos >> PAGE_CACHE_SHIFT;
1301 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1302 int err = 0;
1303 int faili;
1304
1305 for (i = 0; i < num_pages; i++) {
1306 pages[i] = find_or_create_page(inode->i_mapping, index + i,
1307 mask | __GFP_WRITE);
1308 if (!pages[i]) {
1309 faili = i - 1;
1310 err = -ENOMEM;
1311 goto fail;
1312 }
1313
1314 if (i == 0)
1315 err = prepare_uptodate_page(pages[i], pos,
1316 force_uptodate);
1317 if (i == num_pages - 1)
1318 err = prepare_uptodate_page(pages[i],
1319 pos + write_bytes, false);
1320 if (err) {
1321 page_cache_release(pages[i]);
1322 faili = i - 1;
1323 goto fail;
1324 }
1325 wait_on_page_writeback(pages[i]);
1326 }
1327
1328 return 0;
1329fail:
1330 while (faili >= 0) {
1331 unlock_page(pages[faili]);
1332 page_cache_release(pages[faili]);
1333 faili--;
1334 }
1335 return err;
1336
1337}
1338
1339/*
1340 * This function locks the extent and properly waits for data=ordered extents
1341 * to finish before allowing the pages to be modified if need.
1342 *
1343 * The return value:
1344 * 1 - the extent is locked
1345 * 0 - the extent is not locked, and everything is OK
1346 * -EAGAIN - need re-prepare the pages
1347 * the other < 0 number - Something wrong happens
1348 */
1349static noinline int
1350lock_and_cleanup_extent_if_need(struct inode *inode, struct page **pages,
1351 size_t num_pages, loff_t pos,
1352 u64 *lockstart, u64 *lockend,
1353 struct extent_state **cached_state)
1354{
1355 u64 start_pos;
1356 u64 last_pos;
1357 int i;
1358 int ret = 0;
1359
1360 start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1);
1361 last_pos = start_pos + ((u64)num_pages << PAGE_CACHE_SHIFT) - 1;
1362
1363 if (start_pos < inode->i_size) {
1364 struct btrfs_ordered_extent *ordered;
1365 lock_extent_bits(&BTRFS_I(inode)->io_tree,
1366 start_pos, last_pos, 0, cached_state);
1367 ordered = btrfs_lookup_ordered_range(inode, start_pos,
1368 last_pos - start_pos + 1);
1369 if (ordered &&
1370 ordered->file_offset + ordered->len > start_pos &&
1371 ordered->file_offset <= last_pos) {
1372 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1373 start_pos, last_pos,
1374 cached_state, GFP_NOFS);
1375 for (i = 0; i < num_pages; i++) {
1376 unlock_page(pages[i]);
1377 page_cache_release(pages[i]);
1378 }
1379 btrfs_start_ordered_extent(inode, ordered, 1);
1380 btrfs_put_ordered_extent(ordered);
1381 return -EAGAIN;
1382 }
1383 if (ordered)
1384 btrfs_put_ordered_extent(ordered);
1385
1386 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
1387 last_pos, EXTENT_DIRTY | EXTENT_DELALLOC |
1388 EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
1389 0, 0, cached_state, GFP_NOFS);
1390 *lockstart = start_pos;
1391 *lockend = last_pos;
1392 ret = 1;
1393 }
1394
1395 for (i = 0; i < num_pages; i++) {
1396 if (clear_page_dirty_for_io(pages[i]))
1397 account_page_redirty(pages[i]);
1398 set_page_extent_mapped(pages[i]);
1399 WARN_ON(!PageLocked(pages[i]));
1400 }
1401
1402 return ret;
1403}
1404
1405static noinline int check_can_nocow(struct inode *inode, loff_t pos,
1406 size_t *write_bytes)
1407{
1408 struct btrfs_root *root = BTRFS_I(inode)->root;
1409 struct btrfs_ordered_extent *ordered;
1410 u64 lockstart, lockend;
1411 u64 num_bytes;
1412 int ret;
1413
1414 ret = btrfs_start_nocow_write(root);
1415 if (!ret)
1416 return -ENOSPC;
1417
1418 lockstart = round_down(pos, root->sectorsize);
1419 lockend = round_up(pos + *write_bytes, root->sectorsize) - 1;
1420
1421 while (1) {
1422 lock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1423 ordered = btrfs_lookup_ordered_range(inode, lockstart,
1424 lockend - lockstart + 1);
1425 if (!ordered) {
1426 break;
1427 }
1428 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1429 btrfs_start_ordered_extent(inode, ordered, 1);
1430 btrfs_put_ordered_extent(ordered);
1431 }
1432
1433 num_bytes = lockend - lockstart + 1;
1434 ret = can_nocow_extent(inode, lockstart, &num_bytes, NULL, NULL, NULL);
1435 if (ret <= 0) {
1436 ret = 0;
1437 btrfs_end_nocow_write(root);
1438 } else {
1439 *write_bytes = min_t(size_t, *write_bytes ,
1440 num_bytes - pos + lockstart);
1441 }
1442
1443 unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
1444
1445 return ret;
1446}
1447
1448static noinline ssize_t __btrfs_buffered_write(struct file *file,
1449 struct iov_iter *i,
1450 loff_t pos)
1451{
1452 struct inode *inode = file_inode(file);
1453 struct btrfs_root *root = BTRFS_I(inode)->root;
1454 struct page **pages = NULL;
1455 struct extent_state *cached_state = NULL;
1456 u64 release_bytes = 0;
1457 u64 lockstart;
1458 u64 lockend;
1459 unsigned long first_index;
1460 size_t num_written = 0;
1461 int nrptrs;
1462 int ret = 0;
1463 bool only_release_metadata = false;
1464 bool force_page_uptodate = false;
1465 bool need_unlock;
1466
1467 nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
1468 PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
1469 (sizeof(struct page *)));
1470 nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
1471 nrptrs = max(nrptrs, 8);
1472 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1473 if (!pages)
1474 return -ENOMEM;
1475
1476 first_index = pos >> PAGE_CACHE_SHIFT;
1477
1478 while (iov_iter_count(i) > 0) {
1479 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1480 size_t write_bytes = min(iov_iter_count(i),
1481 nrptrs * (size_t)PAGE_CACHE_SIZE -
1482 offset);
1483 size_t num_pages = (write_bytes + offset +
1484 PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1485 size_t reserve_bytes;
1486 size_t dirty_pages;
1487 size_t copied;
1488
1489 WARN_ON(num_pages > nrptrs);
1490
1491 /*
1492 * Fault pages before locking them in prepare_pages
1493 * to avoid recursive lock
1494 */
1495 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1496 ret = -EFAULT;
1497 break;
1498 }
1499
1500 reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
1501 ret = btrfs_check_data_free_space(inode, reserve_bytes);
1502 if (ret == -ENOSPC &&
1503 (BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
1504 BTRFS_INODE_PREALLOC))) {
1505 ret = check_can_nocow(inode, pos, &write_bytes);
1506 if (ret > 0) {
1507 only_release_metadata = true;
1508 /*
1509 * our prealloc extent may be smaller than
1510 * write_bytes, so scale down.
1511 */
1512 num_pages = (write_bytes + offset +
1513 PAGE_CACHE_SIZE - 1) >>
1514 PAGE_CACHE_SHIFT;
1515 reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
1516 ret = 0;
1517 } else {
1518 ret = -ENOSPC;
1519 }
1520 }
1521
1522 if (ret)
1523 break;
1524
1525 ret = btrfs_delalloc_reserve_metadata(inode, reserve_bytes);
1526 if (ret) {
1527 if (!only_release_metadata)
1528 btrfs_free_reserved_data_space(inode,
1529 reserve_bytes);
1530 else
1531 btrfs_end_nocow_write(root);
1532 break;
1533 }
1534
1535 release_bytes = reserve_bytes;
1536 need_unlock = false;
1537again:
1538 /*
1539 * This is going to setup the pages array with the number of
1540 * pages we want, so we don't really need to worry about the
1541 * contents of pages from loop to loop
1542 */
1543 ret = prepare_pages(inode, pages, num_pages,
1544 pos, write_bytes,
1545 force_page_uptodate);
1546 if (ret)
1547 break;
1548
1549 ret = lock_and_cleanup_extent_if_need(inode, pages, num_pages,
1550 pos, &lockstart, &lockend,
1551 &cached_state);
1552 if (ret < 0) {
1553 if (ret == -EAGAIN)
1554 goto again;
1555 break;
1556 } else if (ret > 0) {
1557 need_unlock = true;
1558 ret = 0;
1559 }
1560
1561 copied = btrfs_copy_from_user(pos, num_pages,
1562 write_bytes, pages, i);
1563
1564 /*
1565 * if we have trouble faulting in the pages, fall
1566 * back to one page at a time
1567 */
1568 if (copied < write_bytes)
1569 nrptrs = 1;
1570
1571 if (copied == 0) {
1572 force_page_uptodate = true;
1573 dirty_pages = 0;
1574 } else {
1575 force_page_uptodate = false;
1576 dirty_pages = (copied + offset +
1577 PAGE_CACHE_SIZE - 1) >>
1578 PAGE_CACHE_SHIFT;
1579 }
1580
1581 /*
1582 * If we had a short copy we need to release the excess delaloc
1583 * bytes we reserved. We need to increment outstanding_extents
1584 * because btrfs_delalloc_release_space will decrement it, but
1585 * we still have an outstanding extent for the chunk we actually
1586 * managed to copy.
1587 */
1588 if (num_pages > dirty_pages) {
1589 release_bytes = (num_pages - dirty_pages) <<
1590 PAGE_CACHE_SHIFT;
1591 if (copied > 0) {
1592 spin_lock(&BTRFS_I(inode)->lock);
1593 BTRFS_I(inode)->outstanding_extents++;
1594 spin_unlock(&BTRFS_I(inode)->lock);
1595 }
1596 if (only_release_metadata)
1597 btrfs_delalloc_release_metadata(inode,
1598 release_bytes);
1599 else
1600 btrfs_delalloc_release_space(inode,
1601 release_bytes);
1602 }
1603
1604 release_bytes = dirty_pages << PAGE_CACHE_SHIFT;
1605
1606 if (copied > 0)
1607 ret = btrfs_dirty_pages(root, inode, pages,
1608 dirty_pages, pos, copied,
1609 NULL);
1610 if (need_unlock)
1611 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1612 lockstart, lockend, &cached_state,
1613 GFP_NOFS);
1614 if (ret) {
1615 btrfs_drop_pages(pages, num_pages);
1616 break;
1617 }
1618
1619 release_bytes = 0;
1620 if (only_release_metadata)
1621 btrfs_end_nocow_write(root);
1622
1623 if (only_release_metadata && copied > 0) {
1624 u64 lockstart = round_down(pos, root->sectorsize);
1625 u64 lockend = lockstart +
1626 (dirty_pages << PAGE_CACHE_SHIFT) - 1;
1627
1628 set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
1629 lockend, EXTENT_NORESERVE, NULL,
1630 NULL, GFP_NOFS);
1631 only_release_metadata = false;
1632 }
1633
1634 btrfs_drop_pages(pages, num_pages);
1635
1636 cond_resched();
1637
1638 balance_dirty_pages_ratelimited(inode->i_mapping);
1639 if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1640 btrfs_btree_balance_dirty(root);
1641
1642 pos += copied;
1643 num_written += copied;
1644 }
1645
1646 kfree(pages);
1647
1648 if (release_bytes) {
1649 if (only_release_metadata) {
1650 btrfs_end_nocow_write(root);
1651 btrfs_delalloc_release_metadata(inode, release_bytes);
1652 } else {
1653 btrfs_delalloc_release_space(inode, release_bytes);
1654 }
1655 }
1656
1657 return num_written ? num_written : ret;
1658}
1659
1660static ssize_t __btrfs_direct_write(struct kiocb *iocb,
1661 const struct iovec *iov,
1662 unsigned long nr_segs, loff_t pos,
1663 size_t count, size_t ocount)
1664{
1665 struct file *file = iocb->ki_filp;
1666 struct iov_iter i;
1667 ssize_t written;
1668 ssize_t written_buffered;
1669 loff_t endbyte;
1670 int err;
1671
1672 written = generic_file_direct_write(iocb, iov, &nr_segs, pos,
1673 count, ocount);
1674
1675 if (written < 0 || written == count)
1676 return written;
1677
1678 pos += written;
1679 count -= written;
1680 iov_iter_init(&i, iov, nr_segs, count, written);
1681 written_buffered = __btrfs_buffered_write(file, &i, pos);
1682 if (written_buffered < 0) {
1683 err = written_buffered;
1684 goto out;
1685 }
1686 endbyte = pos + written_buffered - 1;
1687 err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
1688 if (err)
1689 goto out;
1690 written += written_buffered;
1691 iocb->ki_pos = pos + written_buffered;
1692 invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
1693 endbyte >> PAGE_CACHE_SHIFT);
1694out:
1695 return written ? written : err;
1696}
1697
1698static void update_time_for_write(struct inode *inode)
1699{
1700 struct timespec now;
1701
1702 if (IS_NOCMTIME(inode))
1703 return;
1704
1705 now = current_fs_time(inode->i_sb);
1706 if (!timespec_equal(&inode->i_mtime, &now))
1707 inode->i_mtime = now;
1708
1709 if (!timespec_equal(&inode->i_ctime, &now))
1710 inode->i_ctime = now;
1711
1712 if (IS_I_VERSION(inode))
1713 inode_inc_iversion(inode);
1714}
1715
1716static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
1717 const struct iovec *iov,
1718 unsigned long nr_segs, loff_t pos)
1719{
1720 struct file *file = iocb->ki_filp;
1721 struct inode *inode = file_inode(file);
1722 struct btrfs_root *root = BTRFS_I(inode)->root;
1723 u64 start_pos;
1724 u64 end_pos;
1725 ssize_t num_written = 0;
1726 ssize_t err = 0;
1727 size_t count, ocount;
1728 bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
1729
1730 mutex_lock(&inode->i_mutex);
1731
1732 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1733 if (err) {
1734 mutex_unlock(&inode->i_mutex);
1735 goto out;
1736 }
1737 count = ocount;
1738
1739 current->backing_dev_info = inode->i_mapping->backing_dev_info;
1740 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1741 if (err) {
1742 mutex_unlock(&inode->i_mutex);
1743 goto out;
1744 }
1745
1746 if (count == 0) {
1747 mutex_unlock(&inode->i_mutex);
1748 goto out;
1749 }
1750
1751 err = file_remove_suid(file);
1752 if (err) {
1753 mutex_unlock(&inode->i_mutex);
1754 goto out;
1755 }
1756
1757 /*
1758 * If BTRFS flips readonly due to some impossible error
1759 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1760 * although we have opened a file as writable, we have
1761 * to stop this write operation to ensure FS consistency.
1762 */
1763 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1764 mutex_unlock(&inode->i_mutex);
1765 err = -EROFS;
1766 goto out;
1767 }
1768
1769 /*
1770 * We reserve space for updating the inode when we reserve space for the
1771 * extent we are going to write, so we will enospc out there. We don't
1772 * need to start yet another transaction to update the inode as we will
1773 * update the inode when we finish writing whatever data we write.
1774 */
1775 update_time_for_write(inode);
1776
1777 start_pos = round_down(pos, root->sectorsize);
1778 if (start_pos > i_size_read(inode)) {
1779 /* Expand hole size to cover write data, preventing empty gap */
1780 end_pos = round_up(pos + count, root->sectorsize);
1781 err = btrfs_cont_expand(inode, i_size_read(inode), end_pos);
1782 if (err) {
1783 mutex_unlock(&inode->i_mutex);
1784 goto out;
1785 }
1786 }
1787
1788 if (sync)
1789 atomic_inc(&BTRFS_I(inode)->sync_writers);
1790
1791 if (unlikely(file->f_flags & O_DIRECT)) {
1792 num_written = __btrfs_direct_write(iocb, iov, nr_segs,
1793 pos, count, ocount);
1794 } else {
1795 struct iov_iter i;
1796
1797 iov_iter_init(&i, iov, nr_segs, count, num_written);
1798
1799 num_written = __btrfs_buffered_write(file, &i, pos);
1800 if (num_written > 0)
1801 iocb->ki_pos = pos + num_written;
1802 }
1803
1804 mutex_unlock(&inode->i_mutex);
1805
1806 /*
1807 * we want to make sure fsync finds this change
1808 * but we haven't joined a transaction running right now.
1809 *
1810 * Later on, someone is sure to update the inode and get the
1811 * real transid recorded.
1812 *
1813 * We set last_trans now to the fs_info generation + 1,
1814 * this will either be one more than the running transaction
1815 * or the generation used for the next transaction if there isn't
1816 * one running right now.
1817 *
1818 * We also have to set last_sub_trans to the current log transid,
1819 * otherwise subsequent syncs to a file that's been synced in this
1820 * transaction will appear to have already occured.
1821 */
1822 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1823 BTRFS_I(inode)->last_sub_trans = root->log_transid;
1824 if (num_written > 0) {
1825 err = generic_write_sync(file, pos, num_written);
1826 if (err < 0)
1827 num_written = err;
1828 }
1829
1830 if (sync)
1831 atomic_dec(&BTRFS_I(inode)->sync_writers);
1832out:
1833 current->backing_dev_info = NULL;
1834 return num_written ? num_written : err;
1835}
1836
1837int btrfs_release_file(struct inode *inode, struct file *filp)
1838{
1839 /*
1840 * ordered_data_close is set by settattr when we are about to truncate
1841 * a file from a non-zero size to a zero size. This tries to
1842 * flush down new bytes that may have been written if the
1843 * application were using truncate to replace a file in place.
1844 */
1845 if (test_and_clear_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
1846 &BTRFS_I(inode)->runtime_flags)) {
1847 struct btrfs_trans_handle *trans;
1848 struct btrfs_root *root = BTRFS_I(inode)->root;
1849
1850 /*
1851 * We need to block on a committing transaction to keep us from
1852 * throwing a ordered operation on to the list and causing
1853 * something like sync to deadlock trying to flush out this
1854 * inode.
1855 */
1856 trans = btrfs_start_transaction(root, 0);
1857 if (IS_ERR(trans))
1858 return PTR_ERR(trans);
1859 btrfs_add_ordered_operation(trans, BTRFS_I(inode)->root, inode);
1860 btrfs_end_transaction(trans, root);
1861 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1862 filemap_flush(inode->i_mapping);
1863 }
1864 if (filp->private_data)
1865 btrfs_ioctl_trans_end(filp);
1866 return 0;
1867}
1868
1869/*
1870 * fsync call for both files and directories. This logs the inode into
1871 * the tree log instead of forcing full commits whenever possible.
1872 *
1873 * It needs to call filemap_fdatawait so that all ordered extent updates are
1874 * in the metadata btree are up to date for copying to the log.
1875 *
1876 * It drops the inode mutex before doing the tree log commit. This is an
1877 * important optimization for directories because holding the mutex prevents
1878 * new operations on the dir while we write to disk.
1879 */
1880int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
1881{
1882 struct dentry *dentry = file->f_path.dentry;
1883 struct inode *inode = dentry->d_inode;
1884 struct btrfs_root *root = BTRFS_I(inode)->root;
1885 struct btrfs_trans_handle *trans;
1886 struct btrfs_log_ctx ctx;
1887 int ret = 0;
1888 bool full_sync = 0;
1889
1890 trace_btrfs_sync_file(file, datasync);
1891
1892 /*
1893 * We write the dirty pages in the range and wait until they complete
1894 * out of the ->i_mutex. If so, we can flush the dirty pages by
1895 * multi-task, and make the performance up. See
1896 * btrfs_wait_ordered_range for an explanation of the ASYNC check.
1897 */
1898 atomic_inc(&BTRFS_I(inode)->sync_writers);
1899 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
1900 if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1901 &BTRFS_I(inode)->runtime_flags))
1902 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
1903 atomic_dec(&BTRFS_I(inode)->sync_writers);
1904 if (ret)
1905 return ret;
1906
1907 mutex_lock(&inode->i_mutex);
1908
1909 /*
1910 * We flush the dirty pages again to avoid some dirty pages in the
1911 * range being left.
1912 */
1913 atomic_inc(&root->log_batch);
1914 full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1915 &BTRFS_I(inode)->runtime_flags);
1916 if (full_sync) {
1917 ret = btrfs_wait_ordered_range(inode, start, end - start + 1);
1918 if (ret) {
1919 mutex_unlock(&inode->i_mutex);
1920 goto out;
1921 }
1922 }
1923 atomic_inc(&root->log_batch);
1924
1925 /*
1926 * check the transaction that last modified this inode
1927 * and see if its already been committed
1928 */
1929 if (!BTRFS_I(inode)->last_trans) {
1930 mutex_unlock(&inode->i_mutex);
1931 goto out;
1932 }
1933
1934 /*
1935 * if the last transaction that changed this file was before
1936 * the current transaction, we can bail out now without any
1937 * syncing
1938 */
1939 smp_mb();
1940 if (btrfs_inode_in_log(inode, root->fs_info->generation) ||
1941 BTRFS_I(inode)->last_trans <=
1942 root->fs_info->last_trans_committed) {
1943 BTRFS_I(inode)->last_trans = 0;
1944
1945 /*
1946 * We'v had everything committed since the last time we were
1947 * modified so clear this flag in case it was set for whatever
1948 * reason, it's no longer relevant.
1949 */
1950 clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1951 &BTRFS_I(inode)->runtime_flags);
1952 mutex_unlock(&inode->i_mutex);
1953 goto out;
1954 }
1955
1956 /*
1957 * ok we haven't committed the transaction yet, lets do a commit
1958 */
1959 if (file->private_data)
1960 btrfs_ioctl_trans_end(file);
1961
1962 /*
1963 * We use start here because we will need to wait on the IO to complete
1964 * in btrfs_sync_log, which could require joining a transaction (for
1965 * example checking cross references in the nocow path). If we use join
1966 * here we could get into a situation where we're waiting on IO to
1967 * happen that is blocked on a transaction trying to commit. With start
1968 * we inc the extwriter counter, so we wait for all extwriters to exit
1969 * before we start blocking join'ers. This comment is to keep somebody
1970 * from thinking they are super smart and changing this to
1971 * btrfs_join_transaction *cough*Josef*cough*.
1972 */
1973 trans = btrfs_start_transaction(root, 0);
1974 if (IS_ERR(trans)) {
1975 ret = PTR_ERR(trans);
1976 mutex_unlock(&inode->i_mutex);
1977 goto out;
1978 }
1979 trans->sync = true;
1980
1981 btrfs_init_log_ctx(&ctx);
1982
1983 ret = btrfs_log_dentry_safe(trans, root, dentry, &ctx);
1984 if (ret < 0) {
1985 /* Fallthrough and commit/free transaction. */
1986 ret = 1;
1987 }
1988
1989 /* we've logged all the items and now have a consistent
1990 * version of the file in the log. It is possible that
1991 * someone will come in and modify the file, but that's
1992 * fine because the log is consistent on disk, and we
1993 * have references to all of the file's extents
1994 *
1995 * It is possible that someone will come in and log the
1996 * file again, but that will end up using the synchronization
1997 * inside btrfs_sync_log to keep things safe.
1998 */
1999 mutex_unlock(&inode->i_mutex);
2000
2001 if (ret != BTRFS_NO_LOG_SYNC) {
2002 if (!ret) {
2003 ret = btrfs_sync_log(trans, root, &ctx);
2004 if (!ret) {
2005 ret = btrfs_end_transaction(trans, root);
2006 goto out;
2007 }
2008 }
2009 if (!full_sync) {
2010 ret = btrfs_wait_ordered_range(inode, start,
2011 end - start + 1);
2012 if (ret)
2013 goto out;
2014 }
2015 ret = btrfs_commit_transaction(trans, root);
2016 } else {
2017 ret = btrfs_end_transaction(trans, root);
2018 }
2019out:
2020 return ret > 0 ? -EIO : ret;
2021}
2022
2023static const struct vm_operations_struct btrfs_file_vm_ops = {
2024 .fault = filemap_fault,
2025 .map_pages = filemap_map_pages,
2026 .page_mkwrite = btrfs_page_mkwrite,
2027 .remap_pages = generic_file_remap_pages,
2028};
2029
2030static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
2031{
2032 struct address_space *mapping = filp->f_mapping;
2033
2034 if (!mapping->a_ops->readpage)
2035 return -ENOEXEC;
2036
2037 file_accessed(filp);
2038 vma->vm_ops = &btrfs_file_vm_ops;
2039
2040 return 0;
2041}
2042
2043static int hole_mergeable(struct inode *inode, struct extent_buffer *leaf,
2044 int slot, u64 start, u64 end)
2045{
2046 struct btrfs_file_extent_item *fi;
2047 struct btrfs_key key;
2048
2049 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
2050 return 0;
2051
2052 btrfs_item_key_to_cpu(leaf, &key, slot);
2053 if (key.objectid != btrfs_ino(inode) ||
2054 key.type != BTRFS_EXTENT_DATA_KEY)
2055 return 0;
2056
2057 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
2058
2059 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2060 return 0;
2061
2062 if (btrfs_file_extent_disk_bytenr(leaf, fi))
2063 return 0;
2064
2065 if (key.offset == end)
2066 return 1;
2067 if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start)
2068 return 1;
2069 return 0;
2070}
2071
2072static int fill_holes(struct btrfs_trans_handle *trans, struct inode *inode,
2073 struct btrfs_path *path, u64 offset, u64 end)
2074{
2075 struct btrfs_root *root = BTRFS_I(inode)->root;
2076 struct extent_buffer *leaf;
2077 struct btrfs_file_extent_item *fi;
2078 struct extent_map *hole_em;
2079 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2080 struct btrfs_key key;
2081 int ret;
2082
2083 if (btrfs_fs_incompat(root->fs_info, NO_HOLES))
2084 goto out;
2085
2086 key.objectid = btrfs_ino(inode);
2087 key.type = BTRFS_EXTENT_DATA_KEY;
2088 key.offset = offset;
2089
2090 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2091 if (ret < 0)
2092 return ret;
2093 BUG_ON(!ret);
2094
2095 leaf = path->nodes[0];
2096 if (hole_mergeable(inode, leaf, path->slots[0]-1, offset, end)) {
2097 u64 num_bytes;
2098
2099 path->slots[0]--;
2100 fi = btrfs_item_ptr(leaf, path->slots[0],
2101 struct btrfs_file_extent_item);
2102 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) +
2103 end - offset;
2104 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2105 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2106 btrfs_set_file_extent_offset(leaf, fi, 0);
2107 btrfs_mark_buffer_dirty(leaf);
2108 goto out;
2109 }
2110
2111 if (hole_mergeable(inode, leaf, path->slots[0]+1, offset, end)) {
2112 u64 num_bytes;
2113
2114 path->slots[0]++;
2115 key.offset = offset;
2116 btrfs_set_item_key_safe(root, path, &key);
2117 fi = btrfs_item_ptr(leaf, path->slots[0],
2118 struct btrfs_file_extent_item);
2119 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
2120 offset;
2121 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2122 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2123 btrfs_set_file_extent_offset(leaf, fi, 0);
2124 btrfs_mark_buffer_dirty(leaf);
2125 goto out;
2126 }
2127 btrfs_release_path(path);
2128
2129 ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
2130 0, 0, end - offset, 0, end - offset,
2131 0, 0, 0);
2132 if (ret)
2133 return ret;
2134
2135out:
2136 btrfs_release_path(path);
2137
2138 hole_em = alloc_extent_map();
2139 if (!hole_em) {
2140 btrfs_drop_extent_cache(inode, offset, end - 1, 0);
2141 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2142 &BTRFS_I(inode)->runtime_flags);
2143 } else {
2144 hole_em->start = offset;
2145 hole_em->len = end - offset;
2146 hole_em->ram_bytes = hole_em->len;
2147 hole_em->orig_start = offset;
2148
2149 hole_em->block_start = EXTENT_MAP_HOLE;
2150 hole_em->block_len = 0;
2151 hole_em->orig_block_len = 0;
2152 hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
2153 hole_em->compress_type = BTRFS_COMPRESS_NONE;
2154 hole_em->generation = trans->transid;
2155
2156 do {
2157 btrfs_drop_extent_cache(inode, offset, end - 1, 0);
2158 write_lock(&em_tree->lock);
2159 ret = add_extent_mapping(em_tree, hole_em, 1);
2160 write_unlock(&em_tree->lock);
2161 } while (ret == -EEXIST);
2162 free_extent_map(hole_em);
2163 if (ret)
2164 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2165 &BTRFS_I(inode)->runtime_flags);
2166 }
2167
2168 return 0;
2169}
2170
2171static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
2172{
2173 struct btrfs_root *root = BTRFS_I(inode)->root;
2174 struct extent_state *cached_state = NULL;
2175 struct btrfs_path *path;
2176 struct btrfs_block_rsv *rsv;
2177 struct btrfs_trans_handle *trans;
2178 u64 lockstart = round_up(offset, BTRFS_I(inode)->root->sectorsize);
2179 u64 lockend = round_down(offset + len,
2180 BTRFS_I(inode)->root->sectorsize) - 1;
2181 u64 cur_offset = lockstart;
2182 u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
2183 u64 drop_end;
2184 int ret = 0;
2185 int err = 0;
2186 int rsv_count;
2187 bool same_page = ((offset >> PAGE_CACHE_SHIFT) ==
2188 ((offset + len - 1) >> PAGE_CACHE_SHIFT));
2189 bool no_holes = btrfs_fs_incompat(root->fs_info, NO_HOLES);
2190 u64 ino_size = round_up(inode->i_size, PAGE_CACHE_SIZE);
2191
2192 ret = btrfs_wait_ordered_range(inode, offset, len);
2193 if (ret)
2194 return ret;
2195
2196 mutex_lock(&inode->i_mutex);
2197 /*
2198 * We needn't truncate any page which is beyond the end of the file
2199 * because we are sure there is no data there.
2200 */
2201 /*
2202 * Only do this if we are in the same page and we aren't doing the
2203 * entire page.
2204 */
2205 if (same_page && len < PAGE_CACHE_SIZE) {
2206 if (offset < ino_size)
2207 ret = btrfs_truncate_page(inode, offset, len, 0);
2208 mutex_unlock(&inode->i_mutex);
2209 return ret;
2210 }
2211
2212 /* zero back part of the first page */
2213 if (offset < ino_size) {
2214 ret = btrfs_truncate_page(inode, offset, 0, 0);
2215 if (ret) {
2216 mutex_unlock(&inode->i_mutex);
2217 return ret;
2218 }
2219 }
2220
2221 /* zero the front end of the last page */
2222 if (offset + len < ino_size) {
2223 ret = btrfs_truncate_page(inode, offset + len, 0, 1);
2224 if (ret) {
2225 mutex_unlock(&inode->i_mutex);
2226 return ret;
2227 }
2228 }
2229
2230 if (lockend < lockstart) {
2231 mutex_unlock(&inode->i_mutex);
2232 return 0;
2233 }
2234
2235 while (1) {
2236 struct btrfs_ordered_extent *ordered;
2237
2238 truncate_pagecache_range(inode, lockstart, lockend);
2239
2240 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2241 0, &cached_state);
2242 ordered = btrfs_lookup_first_ordered_extent(inode, lockend);
2243
2244 /*
2245 * We need to make sure we have no ordered extents in this range
2246 * and nobody raced in and read a page in this range, if we did
2247 * we need to try again.
2248 */
2249 if ((!ordered ||
2250 (ordered->file_offset + ordered->len <= lockstart ||
2251 ordered->file_offset > lockend)) &&
2252 !test_range_bit(&BTRFS_I(inode)->io_tree, lockstart,
2253 lockend, EXTENT_UPTODATE, 0,
2254 cached_state)) {
2255 if (ordered)
2256 btrfs_put_ordered_extent(ordered);
2257 break;
2258 }
2259 if (ordered)
2260 btrfs_put_ordered_extent(ordered);
2261 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
2262 lockend, &cached_state, GFP_NOFS);
2263 ret = btrfs_wait_ordered_range(inode, lockstart,
2264 lockend - lockstart + 1);
2265 if (ret) {
2266 mutex_unlock(&inode->i_mutex);
2267 return ret;
2268 }
2269 }
2270
2271 path = btrfs_alloc_path();
2272 if (!path) {
2273 ret = -ENOMEM;
2274 goto out;
2275 }
2276
2277 rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
2278 if (!rsv) {
2279 ret = -ENOMEM;
2280 goto out_free;
2281 }
2282 rsv->size = btrfs_calc_trunc_metadata_size(root, 1);
2283 rsv->failfast = 1;
2284
2285 /*
2286 * 1 - update the inode
2287 * 1 - removing the extents in the range
2288 * 1 - adding the hole extent if no_holes isn't set
2289 */
2290 rsv_count = no_holes ? 2 : 3;
2291 trans = btrfs_start_transaction(root, rsv_count);
2292 if (IS_ERR(trans)) {
2293 err = PTR_ERR(trans);
2294 goto out_free;
2295 }
2296
2297 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
2298 min_size);
2299 BUG_ON(ret);
2300 trans->block_rsv = rsv;
2301
2302 while (cur_offset < lockend) {
2303 ret = __btrfs_drop_extents(trans, root, inode, path,
2304 cur_offset, lockend + 1,
2305 &drop_end, 1, 0, 0, NULL);
2306 if (ret != -ENOSPC)
2307 break;
2308
2309 trans->block_rsv = &root->fs_info->trans_block_rsv;
2310
2311 if (cur_offset < ino_size) {
2312 ret = fill_holes(trans, inode, path, cur_offset,
2313 drop_end);
2314 if (ret) {
2315 err = ret;
2316 break;
2317 }
2318 }
2319
2320 cur_offset = drop_end;
2321
2322 ret = btrfs_update_inode(trans, root, inode);
2323 if (ret) {
2324 err = ret;
2325 break;
2326 }
2327
2328 btrfs_end_transaction(trans, root);
2329 btrfs_btree_balance_dirty(root);
2330
2331 trans = btrfs_start_transaction(root, rsv_count);
2332 if (IS_ERR(trans)) {
2333 ret = PTR_ERR(trans);
2334 trans = NULL;
2335 break;
2336 }
2337
2338 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
2339 rsv, min_size);
2340 BUG_ON(ret); /* shouldn't happen */
2341 trans->block_rsv = rsv;
2342 }
2343
2344 if (ret) {
2345 err = ret;
2346 goto out_trans;
2347 }
2348
2349 trans->block_rsv = &root->fs_info->trans_block_rsv;
2350 if (cur_offset < ino_size) {
2351 ret = fill_holes(trans, inode, path, cur_offset, drop_end);
2352 if (ret) {
2353 err = ret;
2354 goto out_trans;
2355 }
2356 }
2357
2358out_trans:
2359 if (!trans)
2360 goto out_free;
2361
2362 inode_inc_iversion(inode);
2363 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
2364
2365 trans->block_rsv = &root->fs_info->trans_block_rsv;
2366 ret = btrfs_update_inode(trans, root, inode);
2367 btrfs_end_transaction(trans, root);
2368 btrfs_btree_balance_dirty(root);
2369out_free:
2370 btrfs_free_path(path);
2371 btrfs_free_block_rsv(root, rsv);
2372out:
2373 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2374 &cached_state, GFP_NOFS);
2375 mutex_unlock(&inode->i_mutex);
2376 if (ret && !err)
2377 err = ret;
2378 return err;
2379}
2380
2381static long btrfs_fallocate(struct file *file, int mode,
2382 loff_t offset, loff_t len)
2383{
2384 struct inode *inode = file_inode(file);
2385 struct extent_state *cached_state = NULL;
2386 struct btrfs_root *root = BTRFS_I(inode)->root;
2387 u64 cur_offset;
2388 u64 last_byte;
2389 u64 alloc_start;
2390 u64 alloc_end;
2391 u64 alloc_hint = 0;
2392 u64 locked_end;
2393 struct extent_map *em;
2394 int blocksize = BTRFS_I(inode)->root->sectorsize;
2395 int ret;
2396
2397 alloc_start = round_down(offset, blocksize);
2398 alloc_end = round_up(offset + len, blocksize);
2399
2400 /* Make sure we aren't being give some crap mode */
2401 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
2402 return -EOPNOTSUPP;
2403
2404 if (mode & FALLOC_FL_PUNCH_HOLE)
2405 return btrfs_punch_hole(inode, offset, len);
2406
2407 /*
2408 * Make sure we have enough space before we do the
2409 * allocation.
2410 */
2411 ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
2412 if (ret)
2413 return ret;
2414 if (root->fs_info->quota_enabled) {
2415 ret = btrfs_qgroup_reserve(root, alloc_end - alloc_start);
2416 if (ret)
2417 goto out_reserve_fail;
2418 }
2419
2420 mutex_lock(&inode->i_mutex);
2421 ret = inode_newsize_ok(inode, alloc_end);
2422 if (ret)
2423 goto out;
2424
2425 if (alloc_start > inode->i_size) {
2426 ret = btrfs_cont_expand(inode, i_size_read(inode),
2427 alloc_start);
2428 if (ret)
2429 goto out;
2430 } else {
2431 /*
2432 * If we are fallocating from the end of the file onward we
2433 * need to zero out the end of the page if i_size lands in the
2434 * middle of a page.
2435 */
2436 ret = btrfs_truncate_page(inode, inode->i_size, 0, 0);
2437 if (ret)
2438 goto out;
2439 }
2440
2441 /*
2442 * wait for ordered IO before we have any locks. We'll loop again
2443 * below with the locks held.
2444 */
2445 ret = btrfs_wait_ordered_range(inode, alloc_start,
2446 alloc_end - alloc_start);
2447 if (ret)
2448 goto out;
2449
2450 locked_end = alloc_end - 1;
2451 while (1) {
2452 struct btrfs_ordered_extent *ordered;
2453
2454 /* the extent lock is ordered inside the running
2455 * transaction
2456 */
2457 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
2458 locked_end, 0, &cached_state);
2459 ordered = btrfs_lookup_first_ordered_extent(inode,
2460 alloc_end - 1);
2461 if (ordered &&
2462 ordered->file_offset + ordered->len > alloc_start &&
2463 ordered->file_offset < alloc_end) {
2464 btrfs_put_ordered_extent(ordered);
2465 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
2466 alloc_start, locked_end,
2467 &cached_state, GFP_NOFS);
2468 /*
2469 * we can't wait on the range with the transaction
2470 * running or with the extent lock held
2471 */
2472 ret = btrfs_wait_ordered_range(inode, alloc_start,
2473 alloc_end - alloc_start);
2474 if (ret)
2475 goto out;
2476 } else {
2477 if (ordered)
2478 btrfs_put_ordered_extent(ordered);
2479 break;
2480 }
2481 }
2482
2483 cur_offset = alloc_start;
2484 while (1) {
2485 u64 actual_end;
2486
2487 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
2488 alloc_end - cur_offset, 0);
2489 if (IS_ERR_OR_NULL(em)) {
2490 if (!em)
2491 ret = -ENOMEM;
2492 else
2493 ret = PTR_ERR(em);
2494 break;
2495 }
2496 last_byte = min(extent_map_end(em), alloc_end);
2497 actual_end = min_t(u64, extent_map_end(em), offset + len);
2498 last_byte = ALIGN(last_byte, blocksize);
2499
2500 if (em->block_start == EXTENT_MAP_HOLE ||
2501 (cur_offset >= inode->i_size &&
2502 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
2503 ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
2504 last_byte - cur_offset,
2505 1 << inode->i_blkbits,
2506 offset + len,
2507 &alloc_hint);
2508
2509 if (ret < 0) {
2510 free_extent_map(em);
2511 break;
2512 }
2513 } else if (actual_end > inode->i_size &&
2514 !(mode & FALLOC_FL_KEEP_SIZE)) {
2515 /*
2516 * We didn't need to allocate any more space, but we
2517 * still extended the size of the file so we need to
2518 * update i_size.
2519 */
2520 inode->i_ctime = CURRENT_TIME;
2521 i_size_write(inode, actual_end);
2522 btrfs_ordered_update_i_size(inode, actual_end, NULL);
2523 }
2524 free_extent_map(em);
2525
2526 cur_offset = last_byte;
2527 if (cur_offset >= alloc_end) {
2528 ret = 0;
2529 break;
2530 }
2531 }
2532 unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
2533 &cached_state, GFP_NOFS);
2534out:
2535 mutex_unlock(&inode->i_mutex);
2536 if (root->fs_info->quota_enabled)
2537 btrfs_qgroup_free(root, alloc_end - alloc_start);
2538out_reserve_fail:
2539 /* Let go of our reservation. */
2540 btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
2541 return ret;
2542}
2543
2544static int find_desired_extent(struct inode *inode, loff_t *offset, int whence)
2545{
2546 struct btrfs_root *root = BTRFS_I(inode)->root;
2547 struct extent_map *em = NULL;
2548 struct extent_state *cached_state = NULL;
2549 u64 lockstart = *offset;
2550 u64 lockend = i_size_read(inode);
2551 u64 start = *offset;
2552 u64 len = i_size_read(inode);
2553 int ret = 0;
2554
2555 lockend = max_t(u64, root->sectorsize, lockend);
2556 if (lockend <= lockstart)
2557 lockend = lockstart + root->sectorsize;
2558
2559 lockend--;
2560 len = lockend - lockstart + 1;
2561
2562 len = max_t(u64, len, root->sectorsize);
2563 if (inode->i_size == 0)
2564 return -ENXIO;
2565
2566 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0,
2567 &cached_state);
2568
2569 while (start < inode->i_size) {
2570 em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
2571 if (IS_ERR(em)) {
2572 ret = PTR_ERR(em);
2573 em = NULL;
2574 break;
2575 }
2576
2577 if (whence == SEEK_HOLE &&
2578 (em->block_start == EXTENT_MAP_HOLE ||
2579 test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
2580 break;
2581 else if (whence == SEEK_DATA &&
2582 (em->block_start != EXTENT_MAP_HOLE &&
2583 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
2584 break;
2585
2586 start = em->start + em->len;
2587 free_extent_map(em);
2588 em = NULL;
2589 cond_resched();
2590 }
2591 free_extent_map(em);
2592 if (!ret) {
2593 if (whence == SEEK_DATA && start >= inode->i_size)
2594 ret = -ENXIO;
2595 else
2596 *offset = min_t(loff_t, start, inode->i_size);
2597 }
2598 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2599 &cached_state, GFP_NOFS);
2600 return ret;
2601}
2602
2603static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
2604{
2605 struct inode *inode = file->f_mapping->host;
2606 int ret;
2607
2608 mutex_lock(&inode->i_mutex);
2609 switch (whence) {
2610 case SEEK_END:
2611 case SEEK_CUR:
2612 offset = generic_file_llseek(file, offset, whence);
2613 goto out;
2614 case SEEK_DATA:
2615 case SEEK_HOLE:
2616 if (offset >= i_size_read(inode)) {
2617 mutex_unlock(&inode->i_mutex);
2618 return -ENXIO;
2619 }
2620
2621 ret = find_desired_extent(inode, &offset, whence);
2622 if (ret) {
2623 mutex_unlock(&inode->i_mutex);
2624 return ret;
2625 }
2626 }
2627
2628 offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
2629out:
2630 mutex_unlock(&inode->i_mutex);
2631 return offset;
2632}
2633
2634const struct file_operations btrfs_file_operations = {
2635 .llseek = btrfs_file_llseek,
2636 .read = do_sync_read,
2637 .write = do_sync_write,
2638 .aio_read = generic_file_aio_read,
2639 .splice_read = generic_file_splice_read,
2640 .aio_write = btrfs_file_aio_write,
2641 .mmap = btrfs_file_mmap,
2642 .open = generic_file_open,
2643 .release = btrfs_release_file,
2644 .fsync = btrfs_sync_file,
2645 .fallocate = btrfs_fallocate,
2646 .unlocked_ioctl = btrfs_ioctl,
2647#ifdef CONFIG_COMPAT
2648 .compat_ioctl = btrfs_ioctl,
2649#endif
2650};
2651
2652void btrfs_auto_defrag_exit(void)
2653{
2654 if (btrfs_inode_defrag_cachep)
2655 kmem_cache_destroy(btrfs_inode_defrag_cachep);
2656}
2657
2658int btrfs_auto_defrag_init(void)
2659{
2660 btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
2661 sizeof(struct inode_defrag), 0,
2662 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
2663 NULL);
2664 if (!btrfs_inode_defrag_cachep)
2665 return -ENOMEM;
2666
2667 return 0;
2668}