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Add linux-next specific files for 20110831
[linux-2.6/next.git] / fs / btrfs / file.c
blobe7872e485f13156459a9f0a4b14296e177f371b3
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/fs.h>
20 #include <linux/pagemap.h>
21 #include <linux/highmem.h>
22 #include <linux/time.h>
23 #include <linux/init.h>
24 #include <linux/string.h>
25 #include <linux/backing-dev.h>
26 #include <linux/mpage.h>
27 #include <linux/falloc.h>
28 #include <linux/swap.h>
29 #include <linux/writeback.h>
30 #include <linux/statfs.h>
31 #include <linux/compat.h>
32 #include <linux/slab.h>
33 #include "ctree.h"
34 #include "disk-io.h"
35 #include "transaction.h"
36 #include "btrfs_inode.h"
37 #include "ioctl.h"
38 #include "print-tree.h"
39 #include "tree-log.h"
40 #include "locking.h"
41 #include "compat.h"
42
43 /*
44 * when auto defrag is enabled we
45 * queue up these defrag structs to remember which
46 * inodes need defragging passes
47 */
48 struct inode_defrag {
49 struct rb_node rb_node;
50 /* objectid */
51 u64 ino;
52 /*
53 * transid where the defrag was added, we search for
54 * extents newer than this
55 */
56 u64 transid;
57
58 /* root objectid */
59 u64 root;
60
61 /* last offset we were able to defrag */
62 u64 last_offset;
63
64 /* if we've wrapped around back to zero once already */
65 int cycled;
66 };
67
68 /* pop a record for an inode into the defrag tree. The lock
69 * must be held already
70 *
71 * If you're inserting a record for an older transid than an
72 * existing record, the transid already in the tree is lowered
73 *
74 * If an existing record is found the defrag item you
75 * pass in is freed
76 */
77 static void __btrfs_add_inode_defrag(struct inode *inode,
78 struct inode_defrag *defrag)
79 {
80 struct btrfs_root *root = BTRFS_I(inode)->root;
81 struct inode_defrag *entry;
82 struct rb_node **p;
83 struct rb_node *parent = NULL;
84
85 p = &root->fs_info->defrag_inodes.rb_node;
86 while (*p) {
87 parent = *p;
88 entry = rb_entry(parent, struct inode_defrag, rb_node);
89
90 if (defrag->ino < entry->ino)
91 p = &parent->rb_left;
92 else if (defrag->ino > entry->ino)
93 p = &parent->rb_right;
94 else {
95 /* if we're reinserting an entry for
96 * an old defrag run, make sure to
97 * lower the transid of our existing record
98 */
99 if (defrag->transid < entry->transid)
100 entry->transid = defrag->transid;
101 if (defrag->last_offset > entry->last_offset)
102 entry->last_offset = defrag->last_offset;
103 goto exists;
104 }
105 }
106 BTRFS_I(inode)->in_defrag = 1;
107 rb_link_node(&defrag->rb_node, parent, p);
108 rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes);
109 return;
110
111 exists:
112 kfree(defrag);
113 return;
114
115 }
116
117 /*
118 * insert a defrag record for this inode if auto defrag is
119 * enabled
120 */
121 int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
122 struct inode *inode)
123 {
124 struct btrfs_root *root = BTRFS_I(inode)->root;
125 struct inode_defrag *defrag;
126 u64 transid;
127
128 if (!btrfs_test_opt(root, AUTO_DEFRAG))
129 return 0;
130
131 if (btrfs_fs_closing(root->fs_info))
132 return 0;
133
134 if (BTRFS_I(inode)->in_defrag)
135 return 0;
136
137 if (trans)
138 transid = trans->transid;
139 else
140 transid = BTRFS_I(inode)->root->last_trans;
141
142 defrag = kzalloc(sizeof(*defrag), GFP_NOFS);
143 if (!defrag)
144 return -ENOMEM;
145
146 defrag->ino = btrfs_ino(inode);
147 defrag->transid = transid;
148 defrag->root = root->root_key.objectid;
149
150 spin_lock(&root->fs_info->defrag_inodes_lock);
151 if (!BTRFS_I(inode)->in_defrag)
152 __btrfs_add_inode_defrag(inode, defrag);
153 else
154 kfree(defrag);
155 spin_unlock(&root->fs_info->defrag_inodes_lock);
156 return 0;
157 }
158
159 /*
160 * must be called with the defrag_inodes lock held
161 */
162 struct inode_defrag *btrfs_find_defrag_inode(struct btrfs_fs_info *info, u64 ino,
163 struct rb_node **next)
164 {
165 struct inode_defrag *entry = NULL;
166 struct rb_node *p;
167 struct rb_node *parent = NULL;
168
169 p = info->defrag_inodes.rb_node;
170 while (p) {
171 parent = p;
172 entry = rb_entry(parent, struct inode_defrag, rb_node);
173
174 if (ino < entry->ino)
175 p = parent->rb_left;
176 else if (ino > entry->ino)
177 p = parent->rb_right;
178 else
179 return entry;
180 }
181
182 if (next) {
183 while (parent && ino > entry->ino) {
184 parent = rb_next(parent);
185 entry = rb_entry(parent, struct inode_defrag, rb_node);
186 }
187 *next = parent;
188 }
189 return NULL;
190 }
191
192 /*
193 * run through the list of inodes in the FS that need
194 * defragging
195 */
196 int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
197 {
198 struct inode_defrag *defrag;
199 struct btrfs_root *inode_root;
200 struct inode *inode;
201 struct rb_node *n;
202 struct btrfs_key key;
203 struct btrfs_ioctl_defrag_range_args range;
204 u64 first_ino = 0;
205 int num_defrag;
206 int defrag_batch = 1024;
207
208 memset(&range, 0, sizeof(range));
209 range.len = (u64)-1;
210
211 atomic_inc(&fs_info->defrag_running);
212 spin_lock(&fs_info->defrag_inodes_lock);
213 while(1) {
214 n = NULL;
215
216 /* find an inode to defrag */
217 defrag = btrfs_find_defrag_inode(fs_info, first_ino, &n);
218 if (!defrag) {
219 if (n)
220 defrag = rb_entry(n, struct inode_defrag, rb_node);
221 else if (first_ino) {
222 first_ino = 0;
223 continue;
224 } else {
225 break;
226 }
227 }
228
229 /* remove it from the rbtree */
230 first_ino = defrag->ino + 1;
231 rb_erase(&defrag->rb_node, &fs_info->defrag_inodes);
232
233 if (btrfs_fs_closing(fs_info))
234 goto next_free;
235
236 spin_unlock(&fs_info->defrag_inodes_lock);
237
238 /* get the inode */
239 key.objectid = defrag->root;
240 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
241 key.offset = (u64)-1;
242 inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
243 if (IS_ERR(inode_root))
244 goto next;
245
246 key.objectid = defrag->ino;
247 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
248 key.offset = 0;
249
250 inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
251 if (IS_ERR(inode))
252 goto next;
253
254 /* do a chunk of defrag */
255 BTRFS_I(inode)->in_defrag = 0;
256 range.start = defrag->last_offset;
257 num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
258 defrag_batch);
259 /*
260 * if we filled the whole defrag batch, there
261 * must be more work to do. Queue this defrag
262 * again
263 */
264 if (num_defrag == defrag_batch) {
265 defrag->last_offset = range.start;
266 __btrfs_add_inode_defrag(inode, defrag);
267 /*
268 * we don't want to kfree defrag, we added it back to
269 * the rbtree
270 */
271 defrag = NULL;
272 } else if (defrag->last_offset && !defrag->cycled) {
273 /*
274 * we didn't fill our defrag batch, but
275 * we didn't start at zero. Make sure we loop
276 * around to the start of the file.
277 */
278 defrag->last_offset = 0;
279 defrag->cycled = 1;
280 __btrfs_add_inode_defrag(inode, defrag);
281 defrag = NULL;
282 }
283
284 iput(inode);
285 next:
286 spin_lock(&fs_info->defrag_inodes_lock);
287 next_free:
288 kfree(defrag);
289 }
290 spin_unlock(&fs_info->defrag_inodes_lock);
291
292 atomic_dec(&fs_info->defrag_running);
293
294 /*
295 * during unmount, we use the transaction_wait queue to
296 * wait for the defragger to stop
297 */
298 wake_up(&fs_info->transaction_wait);
299 return 0;
300 }
301
302 /* simple helper to fault in pages and copy. This should go away
303 * and be replaced with calls into generic code.
304 */
305 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
306 size_t write_bytes,
307 struct page **prepared_pages,
308 struct iov_iter *i)
309 {
310 size_t copied = 0;
311 size_t total_copied = 0;
312 int pg = 0;
313 int offset = pos & (PAGE_CACHE_SIZE - 1);
314
315 while (write_bytes > 0) {
316 size_t count = min_t(size_t,
317 PAGE_CACHE_SIZE - offset, write_bytes);
318 struct page *page = prepared_pages[pg];
319 /*
320 * Copy data from userspace to the current page
321 *
322 * Disable pagefault to avoid recursive lock since
323 * the pages are already locked
324 */
325 pagefault_disable();
326 copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
327 pagefault_enable();
328
329 /* Flush processor's dcache for this page */
330 flush_dcache_page(page);
331
332 /*
333 * if we get a partial write, we can end up with
334 * partially up to date pages. These add
335 * a lot of complexity, so make sure they don't
336 * happen by forcing this copy to be retried.
337 *
338 * The rest of the btrfs_file_write code will fall
339 * back to page at a time copies after we return 0.
340 */
341 if (!PageUptodate(page) && copied < count)
342 copied = 0;
343
344 iov_iter_advance(i, copied);
345 write_bytes -= copied;
346 total_copied += copied;
347
348 /* Return to btrfs_file_aio_write to fault page */
349 if (unlikely(copied == 0))
350 break;
351
352 if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
353 offset += copied;
354 } else {
355 pg++;
356 offset = 0;
357 }
358 }
359 return total_copied;
360 }
361
362 /*
363 * unlocks pages after btrfs_file_write is done with them
364 */
365 void btrfs_drop_pages(struct page **pages, size_t num_pages)
366 {
367 size_t i;
368 for (i = 0; i < num_pages; i++) {
369 /* page checked is some magic around finding pages that
370 * have been modified without going through btrfs_set_page_dirty
371 * clear it here
372 */
373 ClearPageChecked(pages[i]);
374 unlock_page(pages[i]);
375 mark_page_accessed(pages[i]);
376 page_cache_release(pages[i]);
377 }
378 }
379
380 /*
381 * after copy_from_user, pages need to be dirtied and we need to make
382 * sure holes are created between the current EOF and the start of
383 * any next extents (if required).
384 *
385 * this also makes the decision about creating an inline extent vs
386 * doing real data extents, marking pages dirty and delalloc as required.
387 */
388 int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
389 struct page **pages, size_t num_pages,
390 loff_t pos, size_t write_bytes,
391 struct extent_state **cached)
392 {
393 int err = 0;
394 int i;
395 u64 num_bytes;
396 u64 start_pos;
397 u64 end_of_last_block;
398 u64 end_pos = pos + write_bytes;
399 loff_t isize = i_size_read(inode);
400
401 start_pos = pos & ~((u64)root->sectorsize - 1);
402 num_bytes = (write_bytes + pos - start_pos +
403 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
404
405 end_of_last_block = start_pos + num_bytes - 1;
406 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
407 cached);
408 if (err)
409 return err;
410
411 for (i = 0; i < num_pages; i++) {
412 struct page *p = pages[i];
413 SetPageUptodate(p);
414 ClearPageChecked(p);
415 set_page_dirty(p);
416 }
417
418 /*
419 * we've only changed i_size in ram, and we haven't updated
420 * the disk i_size. There is no need to log the inode
421 * at this time.
422 */
423 if (end_pos > isize)
424 i_size_write(inode, end_pos);
425 return 0;
426 }
427
428 /*
429 * this drops all the extents in the cache that intersect the range
430 * [start, end]. Existing extents are split as required.
431 */
432 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
433 int skip_pinned)
434 {
435 struct extent_map *em;
436 struct extent_map *split = NULL;
437 struct extent_map *split2 = NULL;
438 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
439 u64 len = end - start + 1;
440 int ret;
441 int testend = 1;
442 unsigned long flags;
443 int compressed = 0;
444
445 WARN_ON(end < start);
446 if (end == (u64)-1) {
447 len = (u64)-1;
448 testend = 0;
449 }
450 while (1) {
451 if (!split)
452 split = alloc_extent_map();
453 if (!split2)
454 split2 = alloc_extent_map();
455 BUG_ON(!split || !split2);
456
457 write_lock(&em_tree->lock);
458 em = lookup_extent_mapping(em_tree, start, len);
459 if (!em) {
460 write_unlock(&em_tree->lock);
461 break;
462 }
463 flags = em->flags;
464 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
465 if (testend && em->start + em->len >= start + len) {
466 free_extent_map(em);
467 write_unlock(&em_tree->lock);
468 break;
469 }
470 start = em->start + em->len;
471 if (testend)
472 len = start + len - (em->start + em->len);
473 free_extent_map(em);
474 write_unlock(&em_tree->lock);
475 continue;
476 }
477 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
478 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
479 remove_extent_mapping(em_tree, em);
480
481 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
482 em->start < start) {
483 split->start = em->start;
484 split->len = start - em->start;
485 split->orig_start = em->orig_start;
486 split->block_start = em->block_start;
487
488 if (compressed)
489 split->block_len = em->block_len;
490 else
491 split->block_len = split->len;
492
493 split->bdev = em->bdev;
494 split->flags = flags;
495 split->compress_type = em->compress_type;
496 ret = add_extent_mapping(em_tree, split);
497 BUG_ON(ret);
498 free_extent_map(split);
499 split = split2;
500 split2 = NULL;
501 }
502 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
503 testend && em->start + em->len > start + len) {
504 u64 diff = start + len - em->start;
505
506 split->start = start + len;
507 split->len = em->start + em->len - (start + len);
508 split->bdev = em->bdev;
509 split->flags = flags;
510 split->compress_type = em->compress_type;
511
512 if (compressed) {
513 split->block_len = em->block_len;
514 split->block_start = em->block_start;
515 split->orig_start = em->orig_start;
516 } else {
517 split->block_len = split->len;
518 split->block_start = em->block_start + diff;
519 split->orig_start = split->start;
520 }
521
522 ret = add_extent_mapping(em_tree, split);
523 BUG_ON(ret);
524 free_extent_map(split);
525 split = NULL;
526 }
527 write_unlock(&em_tree->lock);
528
529 /* once for us */
530 free_extent_map(em);
531 /* once for the tree*/
532 free_extent_map(em);
533 }
534 if (split)
535 free_extent_map(split);
536 if (split2)
537 free_extent_map(split2);
538 return 0;
539 }
540
541 /*
542 * this is very complex, but the basic idea is to drop all extents
543 * in the range start - end. hint_block is filled in with a block number
544 * that would be a good hint to the block allocator for this file.
545 *
546 * If an extent intersects the range but is not entirely inside the range
547 * it is either truncated or split. Anything entirely inside the range
548 * is deleted from the tree.
549 */
550 int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
551 u64 start, u64 end, u64 *hint_byte, int drop_cache)
552 {
553 struct btrfs_root *root = BTRFS_I(inode)->root;
554 struct extent_buffer *leaf;
555 struct btrfs_file_extent_item *fi;
556 struct btrfs_path *path;
557 struct btrfs_key key;
558 struct btrfs_key new_key;
559 u64 ino = btrfs_ino(inode);
560 u64 search_start = start;
561 u64 disk_bytenr = 0;
562 u64 num_bytes = 0;
563 u64 extent_offset = 0;
564 u64 extent_end = 0;
565 int del_nr = 0;
566 int del_slot = 0;
567 int extent_type;
568 int recow;
569 int ret;
570
571 if (drop_cache)
572 btrfs_drop_extent_cache(inode, start, end - 1, 0);
573
574 path = btrfs_alloc_path();
575 if (!path)
576 return -ENOMEM;
577
578 while (1) {
579 recow = 0;
580 ret = btrfs_lookup_file_extent(trans, root, path, ino,
581 search_start, -1);
582 if (ret < 0)
583 break;
584 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
585 leaf = path->nodes[0];
586 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
587 if (key.objectid == ino &&
588 key.type == BTRFS_EXTENT_DATA_KEY)
589 path->slots[0]--;
590 }
591 ret = 0;
592 next_slot:
593 leaf = path->nodes[0];
594 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
595 BUG_ON(del_nr > 0);
596 ret = btrfs_next_leaf(root, path);
597 if (ret < 0)
598 break;
599 if (ret > 0) {
600 ret = 0;
601 break;
602 }
603 leaf = path->nodes[0];
604 recow = 1;
605 }
606
607 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
608 if (key.objectid > ino ||
609 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
610 break;
611
612 fi = btrfs_item_ptr(leaf, path->slots[0],
613 struct btrfs_file_extent_item);
614 extent_type = btrfs_file_extent_type(leaf, fi);
615
616 if (extent_type == BTRFS_FILE_EXTENT_REG ||
617 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
618 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
619 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
620 extent_offset = btrfs_file_extent_offset(leaf, fi);
621 extent_end = key.offset +
622 btrfs_file_extent_num_bytes(leaf, fi);
623 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
624 extent_end = key.offset +
625 btrfs_file_extent_inline_len(leaf, fi);
626 } else {
627 WARN_ON(1);
628 extent_end = search_start;
629 }
630
631 if (extent_end <= search_start) {
632 path->slots[0]++;
633 goto next_slot;
634 }
635
636 search_start = max(key.offset, start);
637 if (recow) {
638 btrfs_release_path(path);
639 continue;
640 }
641
642 /*
643 * | - range to drop - |
644 * | -------- extent -------- |
645 */
646 if (start > key.offset && end < extent_end) {
647 BUG_ON(del_nr > 0);
648 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
649
650 memcpy(&new_key, &key, sizeof(new_key));
651 new_key.offset = start;
652 ret = btrfs_duplicate_item(trans, root, path,
653 &new_key);
654 if (ret == -EAGAIN) {
655 btrfs_release_path(path);
656 continue;
657 }
658 if (ret < 0)
659 break;
660
661 leaf = path->nodes[0];
662 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
663 struct btrfs_file_extent_item);
664 btrfs_set_file_extent_num_bytes(leaf, fi,
665 start - key.offset);
666
667 fi = btrfs_item_ptr(leaf, path->slots[0],
668 struct btrfs_file_extent_item);
669
670 extent_offset += start - key.offset;
671 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
672 btrfs_set_file_extent_num_bytes(leaf, fi,
673 extent_end - start);
674 btrfs_mark_buffer_dirty(leaf);
675
676 if (disk_bytenr > 0) {
677 ret = btrfs_inc_extent_ref(trans, root,
678 disk_bytenr, num_bytes, 0,
679 root->root_key.objectid,
680 new_key.objectid,
681 start - extent_offset);
682 BUG_ON(ret);
683 *hint_byte = disk_bytenr;
684 }
685 key.offset = start;
686 }
687 /*
688 * | ---- range to drop ----- |
689 * | -------- extent -------- |
690 */
691 if (start <= key.offset && end < extent_end) {
692 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
693
694 memcpy(&new_key, &key, sizeof(new_key));
695 new_key.offset = end;
696 btrfs_set_item_key_safe(trans, root, path, &new_key);
697
698 extent_offset += end - key.offset;
699 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
700 btrfs_set_file_extent_num_bytes(leaf, fi,
701 extent_end - end);
702 btrfs_mark_buffer_dirty(leaf);
703 if (disk_bytenr > 0) {
704 inode_sub_bytes(inode, end - key.offset);
705 *hint_byte = disk_bytenr;
706 }
707 break;
708 }
709
710 search_start = extent_end;
711 /*
712 * | ---- range to drop ----- |
713 * | -------- extent -------- |
714 */
715 if (start > key.offset && end >= extent_end) {
716 BUG_ON(del_nr > 0);
717 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
718
719 btrfs_set_file_extent_num_bytes(leaf, fi,
720 start - key.offset);
721 btrfs_mark_buffer_dirty(leaf);
722 if (disk_bytenr > 0) {
723 inode_sub_bytes(inode, extent_end - start);
724 *hint_byte = disk_bytenr;
725 }
726 if (end == extent_end)
727 break;
728
729 path->slots[0]++;
730 goto next_slot;
731 }
732
733 /*
734 * | ---- range to drop ----- |
735 * | ------ extent ------ |
736 */
737 if (start <= key.offset && end >= extent_end) {
738 if (del_nr == 0) {
739 del_slot = path->slots[0];
740 del_nr = 1;
741 } else {
742 BUG_ON(del_slot + del_nr != path->slots[0]);
743 del_nr++;
744 }
745
746 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
747 inode_sub_bytes(inode,
748 extent_end - key.offset);
749 extent_end = ALIGN(extent_end,
750 root->sectorsize);
751 } else if (disk_bytenr > 0) {
752 ret = btrfs_free_extent(trans, root,
753 disk_bytenr, num_bytes, 0,
754 root->root_key.objectid,
755 key.objectid, key.offset -
756 extent_offset);
757 BUG_ON(ret);
758 inode_sub_bytes(inode,
759 extent_end - key.offset);
760 *hint_byte = disk_bytenr;
761 }
762
763 if (end == extent_end)
764 break;
765
766 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
767 path->slots[0]++;
768 goto next_slot;
769 }
770
771 ret = btrfs_del_items(trans, root, path, del_slot,
772 del_nr);
773 BUG_ON(ret);
774
775 del_nr = 0;
776 del_slot = 0;
777
778 btrfs_release_path(path);
779 continue;
780 }
781
782 BUG_ON(1);
783 }
784
785 if (del_nr > 0) {
786 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
787 BUG_ON(ret);
788 }
789
790 btrfs_free_path(path);
791 return ret;
792 }
793
794 static int extent_mergeable(struct extent_buffer *leaf, int slot,
795 u64 objectid, u64 bytenr, u64 orig_offset,
796 u64 *start, u64 *end)
797 {
798 struct btrfs_file_extent_item *fi;
799 struct btrfs_key key;
800 u64 extent_end;
801
802 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
803 return 0;
804
805 btrfs_item_key_to_cpu(leaf, &key, slot);
806 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
807 return 0;
808
809 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
810 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
811 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
812 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
813 btrfs_file_extent_compression(leaf, fi) ||
814 btrfs_file_extent_encryption(leaf, fi) ||
815 btrfs_file_extent_other_encoding(leaf, fi))
816 return 0;
817
818 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
819 if ((*start && *start != key.offset) || (*end && *end != extent_end))
820 return 0;
821
822 *start = key.offset;
823 *end = extent_end;
824 return 1;
825 }
826
827 /*
828 * Mark extent in the range start - end as written.
829 *
830 * This changes extent type from 'pre-allocated' to 'regular'. If only
831 * part of extent is marked as written, the extent will be split into
832 * two or three.
833 */
834 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
835 struct inode *inode, u64 start, u64 end)
836 {
837 struct btrfs_root *root = BTRFS_I(inode)->root;
838 struct extent_buffer *leaf;
839 struct btrfs_path *path;
840 struct btrfs_file_extent_item *fi;
841 struct btrfs_key key;
842 struct btrfs_key new_key;
843 u64 bytenr;
844 u64 num_bytes;
845 u64 extent_end;
846 u64 orig_offset;
847 u64 other_start;
848 u64 other_end;
849 u64 split;
850 int del_nr = 0;
851 int del_slot = 0;
852 int recow;
853 int ret;
854 u64 ino = btrfs_ino(inode);
855
856 btrfs_drop_extent_cache(inode, start, end - 1, 0);
857
858 path = btrfs_alloc_path();
859 if (!path)
860 return -ENOMEM;
861 again:
862 recow = 0;
863 split = start;
864 key.objectid = ino;
865 key.type = BTRFS_EXTENT_DATA_KEY;
866 key.offset = split;
867
868 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
869 if (ret < 0)
870 goto out;
871 if (ret > 0 && path->slots[0] > 0)
872 path->slots[0]--;
873
874 leaf = path->nodes[0];
875 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
876 BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
877 fi = btrfs_item_ptr(leaf, path->slots[0],
878 struct btrfs_file_extent_item);
879 BUG_ON(btrfs_file_extent_type(leaf, fi) !=
880 BTRFS_FILE_EXTENT_PREALLOC);
881 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
882 BUG_ON(key.offset > start || extent_end < end);
883
884 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
885 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
886 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
887 memcpy(&new_key, &key, sizeof(new_key));
888
889 if (start == key.offset && end < extent_end) {
890 other_start = 0;
891 other_end = start;
892 if (extent_mergeable(leaf, path->slots[0] - 1,
893 ino, bytenr, orig_offset,
894 &other_start, &other_end)) {
895 new_key.offset = end;
896 btrfs_set_item_key_safe(trans, root, path, &new_key);
897 fi = btrfs_item_ptr(leaf, path->slots[0],
898 struct btrfs_file_extent_item);
899 btrfs_set_file_extent_num_bytes(leaf, fi,
900 extent_end - end);
901 btrfs_set_file_extent_offset(leaf, fi,
902 end - orig_offset);
903 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
904 struct btrfs_file_extent_item);
905 btrfs_set_file_extent_num_bytes(leaf, fi,
906 end - other_start);
907 btrfs_mark_buffer_dirty(leaf);
908 goto out;
909 }
910 }
911
912 if (start > key.offset && end == extent_end) {
913 other_start = end;
914 other_end = 0;
915 if (extent_mergeable(leaf, path->slots[0] + 1,
916 ino, bytenr, orig_offset,
917 &other_start, &other_end)) {
918 fi = btrfs_item_ptr(leaf, path->slots[0],
919 struct btrfs_file_extent_item);
920 btrfs_set_file_extent_num_bytes(leaf, fi,
921 start - key.offset);
922 path->slots[0]++;
923 new_key.offset = start;
924 btrfs_set_item_key_safe(trans, root, path, &new_key);
925
926 fi = btrfs_item_ptr(leaf, path->slots[0],
927 struct btrfs_file_extent_item);
928 btrfs_set_file_extent_num_bytes(leaf, fi,
929 other_end - start);
930 btrfs_set_file_extent_offset(leaf, fi,
931 start - orig_offset);
932 btrfs_mark_buffer_dirty(leaf);
933 goto out;
934 }
935 }
936
937 while (start > key.offset || end < extent_end) {
938 if (key.offset == start)
939 split = end;
940
941 new_key.offset = split;
942 ret = btrfs_duplicate_item(trans, root, path, &new_key);
943 if (ret == -EAGAIN) {
944 btrfs_release_path(path);
945 goto again;
946 }
947 BUG_ON(ret < 0);
948
949 leaf = path->nodes[0];
950 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
951 struct btrfs_file_extent_item);
952 btrfs_set_file_extent_num_bytes(leaf, fi,
953 split - key.offset);
954
955 fi = btrfs_item_ptr(leaf, path->slots[0],
956 struct btrfs_file_extent_item);
957
958 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
959 btrfs_set_file_extent_num_bytes(leaf, fi,
960 extent_end - split);
961 btrfs_mark_buffer_dirty(leaf);
962
963 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
964 root->root_key.objectid,
965 ino, orig_offset);
966 BUG_ON(ret);
967
968 if (split == start) {
969 key.offset = start;
970 } else {
971 BUG_ON(start != key.offset);
972 path->slots[0]--;
973 extent_end = end;
974 }
975 recow = 1;
976 }
977
978 other_start = end;
979 other_end = 0;
980 if (extent_mergeable(leaf, path->slots[0] + 1,
981 ino, bytenr, orig_offset,
982 &other_start, &other_end)) {
983 if (recow) {
984 btrfs_release_path(path);
985 goto again;
986 }
987 extent_end = other_end;
988 del_slot = path->slots[0] + 1;
989 del_nr++;
990 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
991 0, root->root_key.objectid,
992 ino, orig_offset);
993 BUG_ON(ret);
994 }
995 other_start = 0;
996 other_end = start;
997 if (extent_mergeable(leaf, path->slots[0] - 1,
998 ino, bytenr, orig_offset,
999 &other_start, &other_end)) {
1000 if (recow) {
1001 btrfs_release_path(path);
1002 goto again;
1003 }
1004 key.offset = other_start;
1005 del_slot = path->slots[0];
1006 del_nr++;
1007 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1008 0, root->root_key.objectid,
1009 ino, orig_offset);
1010 BUG_ON(ret);
1011 }
1012 if (del_nr == 0) {
1013 fi = btrfs_item_ptr(leaf, path->slots[0],
1014 struct btrfs_file_extent_item);
1015 btrfs_set_file_extent_type(leaf, fi,
1016 BTRFS_FILE_EXTENT_REG);
1017 btrfs_mark_buffer_dirty(leaf);
1018 } else {
1019 fi = btrfs_item_ptr(leaf, del_slot - 1,
1020 struct btrfs_file_extent_item);
1021 btrfs_set_file_extent_type(leaf, fi,
1022 BTRFS_FILE_EXTENT_REG);
1023 btrfs_set_file_extent_num_bytes(leaf, fi,
1024 extent_end - key.offset);
1025 btrfs_mark_buffer_dirty(leaf);
1026
1027 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1028 BUG_ON(ret);
1029 }
1030 out:
1031 btrfs_free_path(path);
1032 return 0;
1033 }
1034
1035 /*
1036 * on error we return an unlocked page and the error value
1037 * on success we return a locked page and 0
1038 */
1039 static int prepare_uptodate_page(struct page *page, u64 pos)
1040 {
1041 int ret = 0;
1042
1043 if ((pos & (PAGE_CACHE_SIZE - 1)) && !PageUptodate(page)) {
1044 ret = btrfs_readpage(NULL, page);
1045 if (ret)
1046 return ret;
1047 lock_page(page);
1048 if (!PageUptodate(page)) {
1049 unlock_page(page);
1050 return -EIO;
1051 }
1052 }
1053 return 0;
1054 }
1055
1056 /*
1057 * this gets pages into the page cache and locks them down, it also properly
1058 * waits for data=ordered extents to finish before allowing the pages to be
1059 * modified.
1060 */
1061 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
1062 struct page **pages, size_t num_pages,
1063 loff_t pos, unsigned long first_index,
1064 size_t write_bytes)
1065 {
1066 struct extent_state *cached_state = NULL;
1067 int i;
1068 unsigned long index = pos >> PAGE_CACHE_SHIFT;
1069 struct inode *inode = fdentry(file)->d_inode;
1070 int err = 0;
1071 int faili = 0;
1072 u64 start_pos;
1073 u64 last_pos;
1074
1075 start_pos = pos & ~((u64)root->sectorsize - 1);
1076 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
1077
1078 if (start_pos > inode->i_size) {
1079 err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
1080 if (err)
1081 return err;
1082 }
1083
1084 again:
1085 for (i = 0; i < num_pages; i++) {
1086 pages[i] = find_or_create_page(inode->i_mapping, index + i,
1087 GFP_NOFS);
1088 if (!pages[i]) {
1089 faili = i - 1;
1090 err = -ENOMEM;
1091 goto fail;
1092 }
1093
1094 if (i == 0)
1095 err = prepare_uptodate_page(pages[i], pos);
1096 if (i == num_pages - 1)
1097 err = prepare_uptodate_page(pages[i],
1098 pos + write_bytes);
1099 if (err) {
1100 page_cache_release(pages[i]);
1101 faili = i - 1;
1102 goto fail;
1103 }
1104 wait_on_page_writeback(pages[i]);
1105 }
1106 err = 0;
1107 if (start_pos < inode->i_size) {
1108 struct btrfs_ordered_extent *ordered;
1109 lock_extent_bits(&BTRFS_I(inode)->io_tree,
1110 start_pos, last_pos - 1, 0, &cached_state,
1111 GFP_NOFS);
1112 ordered = btrfs_lookup_first_ordered_extent(inode,
1113 last_pos - 1);
1114 if (ordered &&
1115 ordered->file_offset + ordered->len > start_pos &&
1116 ordered->file_offset < last_pos) {
1117 btrfs_put_ordered_extent(ordered);
1118 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1119 start_pos, last_pos - 1,
1120 &cached_state, GFP_NOFS);
1121 for (i = 0; i < num_pages; i++) {
1122 unlock_page(pages[i]);
1123 page_cache_release(pages[i]);
1124 }
1125 btrfs_wait_ordered_range(inode, start_pos,
1126 last_pos - start_pos);
1127 goto again;
1128 }
1129 if (ordered)
1130 btrfs_put_ordered_extent(ordered);
1131
1132 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
1133 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1134 EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
1135 GFP_NOFS);
1136 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1137 start_pos, last_pos - 1, &cached_state,
1138 GFP_NOFS);
1139 }
1140 for (i = 0; i < num_pages; i++) {
1141 clear_page_dirty_for_io(pages[i]);
1142 set_page_extent_mapped(pages[i]);
1143 WARN_ON(!PageLocked(pages[i]));
1144 }
1145 return 0;
1146 fail:
1147 while (faili >= 0) {
1148 unlock_page(pages[faili]);
1149 page_cache_release(pages[faili]);
1150 faili--;
1151 }
1152 return err;
1153
1154 }
1155
1156 static noinline ssize_t __btrfs_buffered_write(struct file *file,
1157 struct iov_iter *i,
1158 loff_t pos)
1159 {
1160 struct inode *inode = fdentry(file)->d_inode;
1161 struct btrfs_root *root = BTRFS_I(inode)->root;
1162 struct page **pages = NULL;
1163 unsigned long first_index;
1164 size_t num_written = 0;
1165 int nrptrs;
1166 int ret = 0;
1167
1168 nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
1169 PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
1170 (sizeof(struct page *)));
1171 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1172 if (!pages)
1173 return -ENOMEM;
1174
1175 first_index = pos >> PAGE_CACHE_SHIFT;
1176
1177 while (iov_iter_count(i) > 0) {
1178 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1179 size_t write_bytes = min(iov_iter_count(i),
1180 nrptrs * (size_t)PAGE_CACHE_SIZE -
1181 offset);
1182 size_t num_pages = (write_bytes + offset +
1183 PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1184 size_t dirty_pages;
1185 size_t copied;
1186
1187 WARN_ON(num_pages > nrptrs);
1188
1189 /*
1190 * Fault pages before locking them in prepare_pages
1191 * to avoid recursive lock
1192 */
1193 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1194 ret = -EFAULT;
1195 break;
1196 }
1197
1198 ret = btrfs_delalloc_reserve_space(inode,
1199 num_pages << PAGE_CACHE_SHIFT);
1200 if (ret)
1201 break;
1202
1203 /*
1204 * This is going to setup the pages array with the number of
1205 * pages we want, so we don't really need to worry about the
1206 * contents of pages from loop to loop
1207 */
1208 ret = prepare_pages(root, file, pages, num_pages,
1209 pos, first_index, write_bytes);
1210 if (ret) {
1211 btrfs_delalloc_release_space(inode,
1212 num_pages << PAGE_CACHE_SHIFT);
1213 break;
1214 }
1215
1216 copied = btrfs_copy_from_user(pos, num_pages,
1217 write_bytes, pages, i);
1218
1219 /*
1220 * if we have trouble faulting in the pages, fall
1221 * back to one page at a time
1222 */
1223 if (copied < write_bytes)
1224 nrptrs = 1;
1225
1226 if (copied == 0)
1227 dirty_pages = 0;
1228 else
1229 dirty_pages = (copied + offset +
1230 PAGE_CACHE_SIZE - 1) >>
1231 PAGE_CACHE_SHIFT;
1232
1233 /*
1234 * If we had a short copy we need to release the excess delaloc
1235 * bytes we reserved. We need to increment outstanding_extents
1236 * because btrfs_delalloc_release_space will decrement it, but
1237 * we still have an outstanding extent for the chunk we actually
1238 * managed to copy.
1239 */
1240 if (num_pages > dirty_pages) {
1241 if (copied > 0) {
1242 spin_lock(&BTRFS_I(inode)->lock);
1243 BTRFS_I(inode)->outstanding_extents++;
1244 spin_unlock(&BTRFS_I(inode)->lock);
1245 }
1246 btrfs_delalloc_release_space(inode,
1247 (num_pages - dirty_pages) <<
1248 PAGE_CACHE_SHIFT);
1249 }
1250
1251 if (copied > 0) {
1252 ret = btrfs_dirty_pages(root, inode, pages,
1253 dirty_pages, pos, copied,
1254 NULL);
1255 if (ret) {
1256 btrfs_delalloc_release_space(inode,
1257 dirty_pages << PAGE_CACHE_SHIFT);
1258 btrfs_drop_pages(pages, num_pages);
1259 break;
1260 }
1261 }
1262
1263 btrfs_drop_pages(pages, num_pages);
1264
1265 cond_resched();
1266
1267 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1268 dirty_pages);
1269 if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1270 btrfs_btree_balance_dirty(root, 1);
1271 btrfs_throttle(root);
1272
1273 pos += copied;
1274 num_written += copied;
1275 }
1276
1277 kfree(pages);
1278
1279 return num_written ? num_written : ret;
1280 }
1281
1282 static ssize_t __btrfs_direct_write(struct kiocb *iocb,
1283 const struct iovec *iov,
1284 unsigned long nr_segs, loff_t pos,
1285 loff_t *ppos, size_t count, size_t ocount)
1286 {
1287 struct file *file = iocb->ki_filp;
1288 struct inode *inode = fdentry(file)->d_inode;
1289 struct iov_iter i;
1290 ssize_t written;
1291 ssize_t written_buffered;
1292 loff_t endbyte;
1293 int err;
1294
1295 written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
1296 count, ocount);
1297
1298 /*
1299 * the generic O_DIRECT will update in-memory i_size after the
1300 * DIOs are done. But our endio handlers that update the on
1301 * disk i_size never update past the in memory i_size. So we
1302 * need one more update here to catch any additions to the
1303 * file
1304 */
1305 if (inode->i_size != BTRFS_I(inode)->disk_i_size) {
1306 btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
1307 mark_inode_dirty(inode);
1308 }
1309
1310 if (written < 0 || written == count)
1311 return written;
1312
1313 pos += written;
1314 count -= written;
1315 iov_iter_init(&i, iov, nr_segs, count, written);
1316 written_buffered = __btrfs_buffered_write(file, &i, pos);
1317 if (written_buffered < 0) {
1318 err = written_buffered;
1319 goto out;
1320 }
1321 endbyte = pos + written_buffered - 1;
1322 err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
1323 if (err)
1324 goto out;
1325 written += written_buffered;
1326 *ppos = pos + written_buffered;
1327 invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
1328 endbyte >> PAGE_CACHE_SHIFT);
1329 out:
1330 return written ? written : err;
1331 }
1332
1333 static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
1334 const struct iovec *iov,
1335 unsigned long nr_segs, loff_t pos)
1336 {
1337 struct file *file = iocb->ki_filp;
1338 struct inode *inode = fdentry(file)->d_inode;
1339 struct btrfs_root *root = BTRFS_I(inode)->root;
1340 loff_t *ppos = &iocb->ki_pos;
1341 ssize_t num_written = 0;
1342 ssize_t err = 0;
1343 size_t count, ocount;
1344
1345 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
1346
1347 mutex_lock(&inode->i_mutex);
1348
1349 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1350 if (err) {
1351 mutex_unlock(&inode->i_mutex);
1352 goto out;
1353 }
1354 count = ocount;
1355
1356 current->backing_dev_info = inode->i_mapping->backing_dev_info;
1357 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1358 if (err) {
1359 mutex_unlock(&inode->i_mutex);
1360 goto out;
1361 }
1362
1363 if (count == 0) {
1364 mutex_unlock(&inode->i_mutex);
1365 goto out;
1366 }
1367
1368 err = file_remove_suid(file);
1369 if (err) {
1370 mutex_unlock(&inode->i_mutex);
1371 goto out;
1372 }
1373
1374 /*
1375 * If BTRFS flips readonly due to some impossible error
1376 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1377 * although we have opened a file as writable, we have
1378 * to stop this write operation to ensure FS consistency.
1379 */
1380 if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
1381 mutex_unlock(&inode->i_mutex);
1382 err = -EROFS;
1383 goto out;
1384 }
1385
1386 file_update_time(file);
1387 BTRFS_I(inode)->sequence++;
1388
1389 if (unlikely(file->f_flags & O_DIRECT)) {
1390 num_written = __btrfs_direct_write(iocb, iov, nr_segs,
1391 pos, ppos, count, ocount);
1392 } else {
1393 struct iov_iter i;
1394
1395 iov_iter_init(&i, iov, nr_segs, count, num_written);
1396
1397 num_written = __btrfs_buffered_write(file, &i, pos);
1398 if (num_written > 0)
1399 *ppos = pos + num_written;
1400 }
1401
1402 mutex_unlock(&inode->i_mutex);
1403
1404 /*
1405 * we want to make sure fsync finds this change
1406 * but we haven't joined a transaction running right now.
1407 *
1408 * Later on, someone is sure to update the inode and get the
1409 * real transid recorded.
1410 *
1411 * We set last_trans now to the fs_info generation + 1,
1412 * this will either be one more than the running transaction
1413 * or the generation used for the next transaction if there isn't
1414 * one running right now.
1415 */
1416 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1417 if (num_written > 0 || num_written == -EIOCBQUEUED) {
1418 err = generic_write_sync(file, pos, num_written);
1419 if (err < 0 && num_written > 0)
1420 num_written = err;
1421 }
1422 out:
1423 current->backing_dev_info = NULL;
1424 return num_written ? num_written : err;
1425 }
1426
1427 int btrfs_release_file(struct inode *inode, struct file *filp)
1428 {
1429 /*
1430 * ordered_data_close is set by settattr when we are about to truncate
1431 * a file from a non-zero size to a zero size. This tries to
1432 * flush down new bytes that may have been written if the
1433 * application were using truncate to replace a file in place.
1434 */
1435 if (BTRFS_I(inode)->ordered_data_close) {
1436 BTRFS_I(inode)->ordered_data_close = 0;
1437 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1438 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1439 filemap_flush(inode->i_mapping);
1440 }
1441 if (filp->private_data)
1442 btrfs_ioctl_trans_end(filp);
1443 return 0;
1444 }
1445
1446 /*
1447 * fsync call for both files and directories. This logs the inode into
1448 * the tree log instead of forcing full commits whenever possible.
1449 *
1450 * It needs to call filemap_fdatawait so that all ordered extent updates are
1451 * in the metadata btree are up to date for copying to the log.
1452 *
1453 * It drops the inode mutex before doing the tree log commit. This is an
1454 * important optimization for directories because holding the mutex prevents
1455 * new operations on the dir while we write to disk.
1456 */
1457 int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
1458 {
1459 struct dentry *dentry = file->f_path.dentry;
1460 struct inode *inode = dentry->d_inode;
1461 struct btrfs_root *root = BTRFS_I(inode)->root;
1462 int ret = 0;
1463 struct btrfs_trans_handle *trans;
1464
1465 trace_btrfs_sync_file(file, datasync);
1466
1467 ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
1468 if (ret)
1469 return ret;
1470 mutex_lock(&inode->i_mutex);
1471
1472 /* we wait first, since the writeback may change the inode */
1473 root->log_batch++;
1474 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1475 root->log_batch++;
1476
1477 /*
1478 * check the transaction that last modified this inode
1479 * and see if its already been committed
1480 */
1481 if (!BTRFS_I(inode)->last_trans) {
1482 mutex_unlock(&inode->i_mutex);
1483 goto out;
1484 }
1485
1486 /*
1487 * if the last transaction that changed this file was before
1488 * the current transaction, we can bail out now without any
1489 * syncing
1490 */
1491 smp_mb();
1492 if (BTRFS_I(inode)->last_trans <=
1493 root->fs_info->last_trans_committed) {
1494 BTRFS_I(inode)->last_trans = 0;
1495 mutex_unlock(&inode->i_mutex);
1496 goto out;
1497 }
1498
1499 /*
1500 * ok we haven't committed the transaction yet, lets do a commit
1501 */
1502 if (file->private_data)
1503 btrfs_ioctl_trans_end(file);
1504
1505 trans = btrfs_start_transaction(root, 0);
1506 if (IS_ERR(trans)) {
1507 ret = PTR_ERR(trans);
1508 mutex_unlock(&inode->i_mutex);
1509 goto out;
1510 }
1511
1512 ret = btrfs_log_dentry_safe(trans, root, dentry);
1513 if (ret < 0) {
1514 mutex_unlock(&inode->i_mutex);
1515 goto out;
1516 }
1517
1518 /* we've logged all the items and now have a consistent
1519 * version of the file in the log. It is possible that
1520 * someone will come in and modify the file, but that's
1521 * fine because the log is consistent on disk, and we
1522 * have references to all of the file's extents
1523 *
1524 * It is possible that someone will come in and log the
1525 * file again, but that will end up using the synchronization
1526 * inside btrfs_sync_log to keep things safe.
1527 */
1528 mutex_unlock(&inode->i_mutex);
1529
1530 if (ret != BTRFS_NO_LOG_SYNC) {
1531 if (ret > 0) {
1532 ret = btrfs_commit_transaction(trans, root);
1533 } else {
1534 ret = btrfs_sync_log(trans, root);
1535 if (ret == 0)
1536 ret = btrfs_end_transaction(trans, root);
1537 else
1538 ret = btrfs_commit_transaction(trans, root);
1539 }
1540 } else {
1541 ret = btrfs_end_transaction(trans, root);
1542 }
1543 out:
1544 return ret > 0 ? -EIO : ret;
1545 }
1546
1547 static const struct vm_operations_struct btrfs_file_vm_ops = {
1548 .fault = filemap_fault,
1549 .page_mkwrite = btrfs_page_mkwrite,
1550 };
1551
1552 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1553 {
1554 struct address_space *mapping = filp->f_mapping;
1555
1556 if (!mapping->a_ops->readpage)
1557 return -ENOEXEC;
1558
1559 file_accessed(filp);
1560 vma->vm_ops = &btrfs_file_vm_ops;
1561 vma->vm_flags |= VM_CAN_NONLINEAR;
1562
1563 return 0;
1564 }
1565
1566 static long btrfs_fallocate(struct file *file, int mode,
1567 loff_t offset, loff_t len)
1568 {
1569 struct inode *inode = file->f_path.dentry->d_inode;
1570 struct extent_state *cached_state = NULL;
1571 u64 cur_offset;
1572 u64 last_byte;
1573 u64 alloc_start;
1574 u64 alloc_end;
1575 u64 alloc_hint = 0;
1576 u64 locked_end;
1577 u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
1578 struct extent_map *em;
1579 int ret;
1580
1581 alloc_start = offset & ~mask;
1582 alloc_end = (offset + len + mask) & ~mask;
1583
1584 /* We only support the FALLOC_FL_KEEP_SIZE mode */
1585 if (mode & ~FALLOC_FL_KEEP_SIZE)
1586 return -EOPNOTSUPP;
1587
1588 /*
1589 * wait for ordered IO before we have any locks. We'll loop again
1590 * below with the locks held.
1591 */
1592 btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
1593
1594 mutex_lock(&inode->i_mutex);
1595 ret = inode_newsize_ok(inode, alloc_end);
1596 if (ret)
1597 goto out;
1598
1599 if (alloc_start > inode->i_size) {
1600 ret = btrfs_cont_expand(inode, i_size_read(inode),
1601 alloc_start);
1602 if (ret)
1603 goto out;
1604 }
1605
1606 ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
1607 if (ret)
1608 goto out;
1609
1610 locked_end = alloc_end - 1;
1611 while (1) {
1612 struct btrfs_ordered_extent *ordered;
1613
1614 /* the extent lock is ordered inside the running
1615 * transaction
1616 */
1617 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
1618 locked_end, 0, &cached_state, GFP_NOFS);
1619 ordered = btrfs_lookup_first_ordered_extent(inode,
1620 alloc_end - 1);
1621 if (ordered &&
1622 ordered->file_offset + ordered->len > alloc_start &&
1623 ordered->file_offset < alloc_end) {
1624 btrfs_put_ordered_extent(ordered);
1625 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1626 alloc_start, locked_end,
1627 &cached_state, GFP_NOFS);
1628 /*
1629 * we can't wait on the range with the transaction
1630 * running or with the extent lock held
1631 */
1632 btrfs_wait_ordered_range(inode, alloc_start,
1633 alloc_end - alloc_start);
1634 } else {
1635 if (ordered)
1636 btrfs_put_ordered_extent(ordered);
1637 break;
1638 }
1639 }
1640
1641 cur_offset = alloc_start;
1642 while (1) {
1643 u64 actual_end;
1644
1645 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
1646 alloc_end - cur_offset, 0);
1647 BUG_ON(IS_ERR_OR_NULL(em));
1648 last_byte = min(extent_map_end(em), alloc_end);
1649 actual_end = min_t(u64, extent_map_end(em), offset + len);
1650 last_byte = (last_byte + mask) & ~mask;
1651
1652 if (em->block_start == EXTENT_MAP_HOLE ||
1653 (cur_offset >= inode->i_size &&
1654 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
1655 ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
1656 last_byte - cur_offset,
1657 1 << inode->i_blkbits,
1658 offset + len,
1659 &alloc_hint);
1660 if (ret < 0) {
1661 free_extent_map(em);
1662 break;
1663 }
1664 } else if (actual_end > inode->i_size &&
1665 !(mode & FALLOC_FL_KEEP_SIZE)) {
1666 /*
1667 * We didn't need to allocate any more space, but we
1668 * still extended the size of the file so we need to
1669 * update i_size.
1670 */
1671 inode->i_ctime = CURRENT_TIME;
1672 i_size_write(inode, actual_end);
1673 btrfs_ordered_update_i_size(inode, actual_end, NULL);
1674 }
1675 free_extent_map(em);
1676
1677 cur_offset = last_byte;
1678 if (cur_offset >= alloc_end) {
1679 ret = 0;
1680 break;
1681 }
1682 }
1683 unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
1684 &cached_state, GFP_NOFS);
1685
1686 btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
1687 out:
1688 mutex_unlock(&inode->i_mutex);
1689 return ret;
1690 }
1691
1692 static int find_desired_extent(struct inode *inode, loff_t *offset, int origin)
1693 {
1694 struct btrfs_root *root = BTRFS_I(inode)->root;
1695 struct extent_map *em;
1696 struct extent_state *cached_state = NULL;
1697 u64 lockstart = *offset;
1698 u64 lockend = i_size_read(inode);
1699 u64 start = *offset;
1700 u64 orig_start = *offset;
1701 u64 len = i_size_read(inode);
1702 u64 last_end = 0;
1703 int ret = 0;
1704
1705 lockend = max_t(u64, root->sectorsize, lockend);
1706 if (lockend <= lockstart)
1707 lockend = lockstart + root->sectorsize;
1708
1709 len = lockend - lockstart + 1;
1710
1711 len = max_t(u64, len, root->sectorsize);
1712 if (inode->i_size == 0)
1713 return -ENXIO;
1714
1715 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0,
1716 &cached_state, GFP_NOFS);
1717
1718 /*
1719 * Delalloc is such a pain. If we have a hole and we have pending
1720 * delalloc for a portion of the hole we will get back a hole that
1721 * exists for the entire range since it hasn't been actually written
1722 * yet. So to take care of this case we need to look for an extent just
1723 * before the position we want in case there is outstanding delalloc
1724 * going on here.
1725 */
1726 if (origin == SEEK_HOLE && start != 0) {
1727 if (start <= root->sectorsize)
1728 em = btrfs_get_extent_fiemap(inode, NULL, 0, 0,
1729 root->sectorsize, 0);
1730 else
1731 em = btrfs_get_extent_fiemap(inode, NULL, 0,
1732 start - root->sectorsize,
1733 root->sectorsize, 0);
1734 if (IS_ERR(em)) {
1735 ret = -ENXIO;
1736 goto out;
1737 }
1738 last_end = em->start + em->len;
1739 if (em->block_start == EXTENT_MAP_DELALLOC)
1740 last_end = min_t(u64, last_end, inode->i_size);
1741 free_extent_map(em);
1742 }
1743
1744 while (1) {
1745 em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
1746 if (IS_ERR(em)) {
1747 ret = -ENXIO;
1748 break;
1749 }
1750
1751 if (em->block_start == EXTENT_MAP_HOLE) {
1752 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
1753 if (last_end <= orig_start) {
1754 free_extent_map(em);
1755 ret = -ENXIO;
1756 break;
1757 }
1758 }
1759
1760 if (origin == SEEK_HOLE) {
1761 *offset = start;
1762 free_extent_map(em);
1763 break;
1764 }
1765 } else {
1766 if (origin == SEEK_DATA) {
1767 if (em->block_start == EXTENT_MAP_DELALLOC) {
1768 if (start >= inode->i_size) {
1769 free_extent_map(em);
1770 ret = -ENXIO;
1771 break;
1772 }
1773 }
1774
1775 *offset = start;
1776 free_extent_map(em);
1777 break;
1778 }
1779 }
1780
1781 start = em->start + em->len;
1782 last_end = em->start + em->len;
1783
1784 if (em->block_start == EXTENT_MAP_DELALLOC)
1785 last_end = min_t(u64, last_end, inode->i_size);
1786
1787 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
1788 free_extent_map(em);
1789 ret = -ENXIO;
1790 break;
1791 }
1792 free_extent_map(em);
1793 cond_resched();
1794 }
1795 if (!ret)
1796 *offset = min(*offset, inode->i_size);
1797 out:
1798 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
1799 &cached_state, GFP_NOFS);
1800 return ret;
1801 }
1802
1803 static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int origin)
1804 {
1805 struct inode *inode = file->f_mapping->host;
1806 int ret;
1807
1808 mutex_lock(&inode->i_mutex);
1809 switch (origin) {
1810 case SEEK_END:
1811 case SEEK_CUR:
1812 offset = generic_file_llseek_unlocked(file, offset, origin);
1813 goto out;
1814 case SEEK_DATA:
1815 case SEEK_HOLE:
1816 ret = find_desired_extent(inode, &offset, origin);
1817 if (ret) {
1818 mutex_unlock(&inode->i_mutex);
1819 return ret;
1820 }
1821 }
1822
1823 if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET)) {
1824 ret = -EINVAL;
1825 goto out;
1826 }
1827 if (offset > inode->i_sb->s_maxbytes) {
1828 ret = -EINVAL;
1829 goto out;
1830 }
1831
1832 /* Special lock needed here? */
1833 if (offset != file->f_pos) {
1834 file->f_pos = offset;
1835 file->f_version = 0;
1836 }
1837 out:
1838 mutex_unlock(&inode->i_mutex);
1839 return offset;
1840 }
1841
1842 const struct file_operations btrfs_file_operations = {
1843 .llseek = btrfs_file_llseek,
1844 .read = do_sync_read,
1845 .write = do_sync_write,
1846 .aio_read = generic_file_aio_read,
1847 .splice_read = generic_file_splice_read,
1848 .aio_write = btrfs_file_aio_write,
1849 .mmap = btrfs_file_mmap,
1850 .open = generic_file_open,
1851 .release = btrfs_release_file,
1852 .fsync = btrfs_sync_file,
1853 .fallocate = btrfs_fallocate,
1854 .unlocked_ioctl = btrfs_ioctl,
1855 #ifdef CONFIG_COMPAT
1856 .compat_ioctl = btrfs_ioctl,
1857 #endif
1858 };
linux-next