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neigh: Pass neighbour entry to output ops.
[linux-2.6/cjktty.git] / fs / btrfs / file.c
blobfa4ef18b66b150a975d4143288b1de699dc0ecf0
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 int __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 0;
110
111 exists:
112 kfree(defrag);
113 return 0;
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 int ret = 0;
127 u64 transid;
128
129 if (!btrfs_test_opt(root, AUTO_DEFRAG))
130 return 0;
131
132 if (btrfs_fs_closing(root->fs_info))
133 return 0;
134
135 if (BTRFS_I(inode)->in_defrag)
136 return 0;
137
138 if (trans)
139 transid = trans->transid;
140 else
141 transid = BTRFS_I(inode)->root->last_trans;
142
143 defrag = kzalloc(sizeof(*defrag), GFP_NOFS);
144 if (!defrag)
145 return -ENOMEM;
146
147 defrag->ino = btrfs_ino(inode);
148 defrag->transid = transid;
149 defrag->root = root->root_key.objectid;
150
151 spin_lock(&root->fs_info->defrag_inodes_lock);
152 if (!BTRFS_I(inode)->in_defrag)
153 ret = __btrfs_add_inode_defrag(inode, defrag);
154 spin_unlock(&root->fs_info->defrag_inodes_lock);
155 return ret;
156 }
157
158 /*
159 * must be called with the defrag_inodes lock held
160 */
161 struct inode_defrag *btrfs_find_defrag_inode(struct btrfs_fs_info *info, u64 ino,
162 struct rb_node **next)
163 {
164 struct inode_defrag *entry = NULL;
165 struct rb_node *p;
166 struct rb_node *parent = NULL;
167
168 p = info->defrag_inodes.rb_node;
169 while (p) {
170 parent = p;
171 entry = rb_entry(parent, struct inode_defrag, rb_node);
172
173 if (ino < entry->ino)
174 p = parent->rb_left;
175 else if (ino > entry->ino)
176 p = parent->rb_right;
177 else
178 return entry;
179 }
180
181 if (next) {
182 while (parent && ino > entry->ino) {
183 parent = rb_next(parent);
184 entry = rb_entry(parent, struct inode_defrag, rb_node);
185 }
186 *next = parent;
187 }
188 return NULL;
189 }
190
191 /*
192 * run through the list of inodes in the FS that need
193 * defragging
194 */
195 int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
196 {
197 struct inode_defrag *defrag;
198 struct btrfs_root *inode_root;
199 struct inode *inode;
200 struct rb_node *n;
201 struct btrfs_key key;
202 struct btrfs_ioctl_defrag_range_args range;
203 u64 first_ino = 0;
204 int num_defrag;
205 int defrag_batch = 1024;
206
207 memset(&range, 0, sizeof(range));
208 range.len = (u64)-1;
209
210 atomic_inc(&fs_info->defrag_running);
211 spin_lock(&fs_info->defrag_inodes_lock);
212 while(1) {
213 n = NULL;
214
215 /* find an inode to defrag */
216 defrag = btrfs_find_defrag_inode(fs_info, first_ino, &n);
217 if (!defrag) {
218 if (n)
219 defrag = rb_entry(n, struct inode_defrag, rb_node);
220 else if (first_ino) {
221 first_ino = 0;
222 continue;
223 } else {
224 break;
225 }
226 }
227
228 /* remove it from the rbtree */
229 first_ino = defrag->ino + 1;
230 rb_erase(&defrag->rb_node, &fs_info->defrag_inodes);
231
232 if (btrfs_fs_closing(fs_info))
233 goto next_free;
234
235 spin_unlock(&fs_info->defrag_inodes_lock);
236
237 /* get the inode */
238 key.objectid = defrag->root;
239 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
240 key.offset = (u64)-1;
241 inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
242 if (IS_ERR(inode_root))
243 goto next;
244
245 key.objectid = defrag->ino;
246 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
247 key.offset = 0;
248
249 inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
250 if (IS_ERR(inode))
251 goto next;
252
253 /* do a chunk of defrag */
254 BTRFS_I(inode)->in_defrag = 0;
255 range.start = defrag->last_offset;
256 num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
257 defrag_batch);
258 /*
259 * if we filled the whole defrag batch, there
260 * must be more work to do. Queue this defrag
261 * again
262 */
263 if (num_defrag == defrag_batch) {
264 defrag->last_offset = range.start;
265 __btrfs_add_inode_defrag(inode, defrag);
266 /*
267 * we don't want to kfree defrag, we added it back to
268 * the rbtree
269 */
270 defrag = NULL;
271 } else if (defrag->last_offset && !defrag->cycled) {
272 /*
273 * we didn't fill our defrag batch, but
274 * we didn't start at zero. Make sure we loop
275 * around to the start of the file.
276 */
277 defrag->last_offset = 0;
278 defrag->cycled = 1;
279 __btrfs_add_inode_defrag(inode, defrag);
280 defrag = NULL;
281 }
282
283 iput(inode);
284 next:
285 spin_lock(&fs_info->defrag_inodes_lock);
286 next_free:
287 kfree(defrag);
288 }
289 spin_unlock(&fs_info->defrag_inodes_lock);
290
291 atomic_dec(&fs_info->defrag_running);
292
293 /*
294 * during unmount, we use the transaction_wait queue to
295 * wait for the defragger to stop
296 */
297 wake_up(&fs_info->transaction_wait);
298 return 0;
299 }
300
301 /* simple helper to fault in pages and copy. This should go away
302 * and be replaced with calls into generic code.
303 */
304 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
305 size_t write_bytes,
306 struct page **prepared_pages,
307 struct iov_iter *i)
308 {
309 size_t copied = 0;
310 size_t total_copied = 0;
311 int pg = 0;
312 int offset = pos & (PAGE_CACHE_SIZE - 1);
313
314 while (write_bytes > 0) {
315 size_t count = min_t(size_t,
316 PAGE_CACHE_SIZE - offset, write_bytes);
317 struct page *page = prepared_pages[pg];
318 /*
319 * Copy data from userspace to the current page
320 *
321 * Disable pagefault to avoid recursive lock since
322 * the pages are already locked
323 */
324 pagefault_disable();
325 copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
326 pagefault_enable();
327
328 /* Flush processor's dcache for this page */
329 flush_dcache_page(page);
330
331 /*
332 * if we get a partial write, we can end up with
333 * partially up to date pages. These add
334 * a lot of complexity, so make sure they don't
335 * happen by forcing this copy to be retried.
336 *
337 * The rest of the btrfs_file_write code will fall
338 * back to page at a time copies after we return 0.
339 */
340 if (!PageUptodate(page) && copied < count)
341 copied = 0;
342
343 iov_iter_advance(i, copied);
344 write_bytes -= copied;
345 total_copied += copied;
346
347 /* Return to btrfs_file_aio_write to fault page */
348 if (unlikely(copied == 0))
349 break;
350
351 if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
352 offset += copied;
353 } else {
354 pg++;
355 offset = 0;
356 }
357 }
358 return total_copied;
359 }
360
361 /*
362 * unlocks pages after btrfs_file_write is done with them
363 */
364 void btrfs_drop_pages(struct page **pages, size_t num_pages)
365 {
366 size_t i;
367 for (i = 0; i < num_pages; i++) {
368 /* page checked is some magic around finding pages that
369 * have been modified without going through btrfs_set_page_dirty
370 * clear it here
371 */
372 ClearPageChecked(pages[i]);
373 unlock_page(pages[i]);
374 mark_page_accessed(pages[i]);
375 page_cache_release(pages[i]);
376 }
377 }
378
379 /*
380 * after copy_from_user, pages need to be dirtied and we need to make
381 * sure holes are created between the current EOF and the start of
382 * any next extents (if required).
383 *
384 * this also makes the decision about creating an inline extent vs
385 * doing real data extents, marking pages dirty and delalloc as required.
386 */
387 int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
388 struct page **pages, size_t num_pages,
389 loff_t pos, size_t write_bytes,
390 struct extent_state **cached)
391 {
392 int err = 0;
393 int i;
394 u64 num_bytes;
395 u64 start_pos;
396 u64 end_of_last_block;
397 u64 end_pos = pos + write_bytes;
398 loff_t isize = i_size_read(inode);
399
400 start_pos = pos & ~((u64)root->sectorsize - 1);
401 num_bytes = (write_bytes + pos - start_pos +
402 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
403
404 end_of_last_block = start_pos + num_bytes - 1;
405 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
406 cached);
407 if (err)
408 return err;
409
410 for (i = 0; i < num_pages; i++) {
411 struct page *p = pages[i];
412 SetPageUptodate(p);
413 ClearPageChecked(p);
414 set_page_dirty(p);
415 }
416
417 /*
418 * we've only changed i_size in ram, and we haven't updated
419 * the disk i_size. There is no need to log the inode
420 * at this time.
421 */
422 if (end_pos > isize)
423 i_size_write(inode, end_pos);
424 return 0;
425 }
426
427 /*
428 * this drops all the extents in the cache that intersect the range
429 * [start, end]. Existing extents are split as required.
430 */
431 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
432 int skip_pinned)
433 {
434 struct extent_map *em;
435 struct extent_map *split = NULL;
436 struct extent_map *split2 = NULL;
437 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
438 u64 len = end - start + 1;
439 int ret;
440 int testend = 1;
441 unsigned long flags;
442 int compressed = 0;
443
444 WARN_ON(end < start);
445 if (end == (u64)-1) {
446 len = (u64)-1;
447 testend = 0;
448 }
449 while (1) {
450 if (!split)
451 split = alloc_extent_map();
452 if (!split2)
453 split2 = alloc_extent_map();
454 BUG_ON(!split || !split2);
455
456 write_lock(&em_tree->lock);
457 em = lookup_extent_mapping(em_tree, start, len);
458 if (!em) {
459 write_unlock(&em_tree->lock);
460 break;
461 }
462 flags = em->flags;
463 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
464 if (testend && em->start + em->len >= start + len) {
465 free_extent_map(em);
466 write_unlock(&em_tree->lock);
467 break;
468 }
469 start = em->start + em->len;
470 if (testend)
471 len = start + len - (em->start + em->len);
472 free_extent_map(em);
473 write_unlock(&em_tree->lock);
474 continue;
475 }
476 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
477 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
478 remove_extent_mapping(em_tree, em);
479
480 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
481 em->start < start) {
482 split->start = em->start;
483 split->len = start - em->start;
484 split->orig_start = em->orig_start;
485 split->block_start = em->block_start;
486
487 if (compressed)
488 split->block_len = em->block_len;
489 else
490 split->block_len = split->len;
491
492 split->bdev = em->bdev;
493 split->flags = flags;
494 split->compress_type = em->compress_type;
495 ret = add_extent_mapping(em_tree, split);
496 BUG_ON(ret);
497 free_extent_map(split);
498 split = split2;
499 split2 = NULL;
500 }
501 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
502 testend && em->start + em->len > start + len) {
503 u64 diff = start + len - em->start;
504
505 split->start = start + len;
506 split->len = em->start + em->len - (start + len);
507 split->bdev = em->bdev;
508 split->flags = flags;
509 split->compress_type = em->compress_type;
510
511 if (compressed) {
512 split->block_len = em->block_len;
513 split->block_start = em->block_start;
514 split->orig_start = em->orig_start;
515 } else {
516 split->block_len = split->len;
517 split->block_start = em->block_start + diff;
518 split->orig_start = split->start;
519 }
520
521 ret = add_extent_mapping(em_tree, split);
522 BUG_ON(ret);
523 free_extent_map(split);
524 split = NULL;
525 }
526 write_unlock(&em_tree->lock);
527
528 /* once for us */
529 free_extent_map(em);
530 /* once for the tree*/
531 free_extent_map(em);
532 }
533 if (split)
534 free_extent_map(split);
535 if (split2)
536 free_extent_map(split2);
537 return 0;
538 }
539
540 /*
541 * this is very complex, but the basic idea is to drop all extents
542 * in the range start - end. hint_block is filled in with a block number
543 * that would be a good hint to the block allocator for this file.
544 *
545 * If an extent intersects the range but is not entirely inside the range
546 * it is either truncated or split. Anything entirely inside the range
547 * is deleted from the tree.
548 */
549 int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
550 u64 start, u64 end, u64 *hint_byte, int drop_cache)
551 {
552 struct btrfs_root *root = BTRFS_I(inode)->root;
553 struct extent_buffer *leaf;
554 struct btrfs_file_extent_item *fi;
555 struct btrfs_path *path;
556 struct btrfs_key key;
557 struct btrfs_key new_key;
558 u64 ino = btrfs_ino(inode);
559 u64 search_start = start;
560 u64 disk_bytenr = 0;
561 u64 num_bytes = 0;
562 u64 extent_offset = 0;
563 u64 extent_end = 0;
564 int del_nr = 0;
565 int del_slot = 0;
566 int extent_type;
567 int recow;
568 int ret;
569
570 if (drop_cache)
571 btrfs_drop_extent_cache(inode, start, end - 1, 0);
572
573 path = btrfs_alloc_path();
574 if (!path)
575 return -ENOMEM;
576
577 while (1) {
578 recow = 0;
579 ret = btrfs_lookup_file_extent(trans, root, path, ino,
580 search_start, -1);
581 if (ret < 0)
582 break;
583 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
584 leaf = path->nodes[0];
585 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
586 if (key.objectid == ino &&
587 key.type == BTRFS_EXTENT_DATA_KEY)
588 path->slots[0]--;
589 }
590 ret = 0;
591 next_slot:
592 leaf = path->nodes[0];
593 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
594 BUG_ON(del_nr > 0);
595 ret = btrfs_next_leaf(root, path);
596 if (ret < 0)
597 break;
598 if (ret > 0) {
599 ret = 0;
600 break;
601 }
602 leaf = path->nodes[0];
603 recow = 1;
604 }
605
606 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
607 if (key.objectid > ino ||
608 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
609 break;
610
611 fi = btrfs_item_ptr(leaf, path->slots[0],
612 struct btrfs_file_extent_item);
613 extent_type = btrfs_file_extent_type(leaf, fi);
614
615 if (extent_type == BTRFS_FILE_EXTENT_REG ||
616 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
617 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
618 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
619 extent_offset = btrfs_file_extent_offset(leaf, fi);
620 extent_end = key.offset +
621 btrfs_file_extent_num_bytes(leaf, fi);
622 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
623 extent_end = key.offset +
624 btrfs_file_extent_inline_len(leaf, fi);
625 } else {
626 WARN_ON(1);
627 extent_end = search_start;
628 }
629
630 if (extent_end <= search_start) {
631 path->slots[0]++;
632 goto next_slot;
633 }
634
635 search_start = max(key.offset, start);
636 if (recow) {
637 btrfs_release_path(path);
638 continue;
639 }
640
641 /*
642 * | - range to drop - |
643 * | -------- extent -------- |
644 */
645 if (start > key.offset && end < extent_end) {
646 BUG_ON(del_nr > 0);
647 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
648
649 memcpy(&new_key, &key, sizeof(new_key));
650 new_key.offset = start;
651 ret = btrfs_duplicate_item(trans, root, path,
652 &new_key);
653 if (ret == -EAGAIN) {
654 btrfs_release_path(path);
655 continue;
656 }
657 if (ret < 0)
658 break;
659
660 leaf = path->nodes[0];
661 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
662 struct btrfs_file_extent_item);
663 btrfs_set_file_extent_num_bytes(leaf, fi,
664 start - key.offset);
665
666 fi = btrfs_item_ptr(leaf, path->slots[0],
667 struct btrfs_file_extent_item);
668
669 extent_offset += start - key.offset;
670 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
671 btrfs_set_file_extent_num_bytes(leaf, fi,
672 extent_end - start);
673 btrfs_mark_buffer_dirty(leaf);
674
675 if (disk_bytenr > 0) {
676 ret = btrfs_inc_extent_ref(trans, root,
677 disk_bytenr, num_bytes, 0,
678 root->root_key.objectid,
679 new_key.objectid,
680 start - extent_offset);
681 BUG_ON(ret);
682 *hint_byte = disk_bytenr;
683 }
684 key.offset = start;
685 }
686 /*
687 * | ---- range to drop ----- |
688 * | -------- extent -------- |
689 */
690 if (start <= key.offset && end < extent_end) {
691 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
692
693 memcpy(&new_key, &key, sizeof(new_key));
694 new_key.offset = end;
695 btrfs_set_item_key_safe(trans, root, path, &new_key);
696
697 extent_offset += end - key.offset;
698 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
699 btrfs_set_file_extent_num_bytes(leaf, fi,
700 extent_end - end);
701 btrfs_mark_buffer_dirty(leaf);
702 if (disk_bytenr > 0) {
703 inode_sub_bytes(inode, end - key.offset);
704 *hint_byte = disk_bytenr;
705 }
706 break;
707 }
708
709 search_start = extent_end;
710 /*
711 * | ---- range to drop ----- |
712 * | -------- extent -------- |
713 */
714 if (start > key.offset && end >= extent_end) {
715 BUG_ON(del_nr > 0);
716 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
717
718 btrfs_set_file_extent_num_bytes(leaf, fi,
719 start - key.offset);
720 btrfs_mark_buffer_dirty(leaf);
721 if (disk_bytenr > 0) {
722 inode_sub_bytes(inode, extent_end - start);
723 *hint_byte = disk_bytenr;
724 }
725 if (end == extent_end)
726 break;
727
728 path->slots[0]++;
729 goto next_slot;
730 }
731
732 /*
733 * | ---- range to drop ----- |
734 * | ------ extent ------ |
735 */
736 if (start <= key.offset && end >= extent_end) {
737 if (del_nr == 0) {
738 del_slot = path->slots[0];
739 del_nr = 1;
740 } else {
741 BUG_ON(del_slot + del_nr != path->slots[0]);
742 del_nr++;
743 }
744
745 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
746 inode_sub_bytes(inode,
747 extent_end - key.offset);
748 extent_end = ALIGN(extent_end,
749 root->sectorsize);
750 } else if (disk_bytenr > 0) {
751 ret = btrfs_free_extent(trans, root,
752 disk_bytenr, num_bytes, 0,
753 root->root_key.objectid,
754 key.objectid, key.offset -
755 extent_offset);
756 BUG_ON(ret);
757 inode_sub_bytes(inode,
758 extent_end - key.offset);
759 *hint_byte = disk_bytenr;
760 }
761
762 if (end == extent_end)
763 break;
764
765 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
766 path->slots[0]++;
767 goto next_slot;
768 }
769
770 ret = btrfs_del_items(trans, root, path, del_slot,
771 del_nr);
772 BUG_ON(ret);
773
774 del_nr = 0;
775 del_slot = 0;
776
777 btrfs_release_path(path);
778 continue;
779 }
780
781 BUG_ON(1);
782 }
783
784 if (del_nr > 0) {
785 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
786 BUG_ON(ret);
787 }
788
789 btrfs_free_path(path);
790 return ret;
791 }
792
793 static int extent_mergeable(struct extent_buffer *leaf, int slot,
794 u64 objectid, u64 bytenr, u64 orig_offset,
795 u64 *start, u64 *end)
796 {
797 struct btrfs_file_extent_item *fi;
798 struct btrfs_key key;
799 u64 extent_end;
800
801 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
802 return 0;
803
804 btrfs_item_key_to_cpu(leaf, &key, slot);
805 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
806 return 0;
807
808 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
809 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
810 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
811 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
812 btrfs_file_extent_compression(leaf, fi) ||
813 btrfs_file_extent_encryption(leaf, fi) ||
814 btrfs_file_extent_other_encoding(leaf, fi))
815 return 0;
816
817 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
818 if ((*start && *start != key.offset) || (*end && *end != extent_end))
819 return 0;
820
821 *start = key.offset;
822 *end = extent_end;
823 return 1;
824 }
825
826 /*
827 * Mark extent in the range start - end as written.
828 *
829 * This changes extent type from 'pre-allocated' to 'regular'. If only
830 * part of extent is marked as written, the extent will be split into
831 * two or three.
832 */
833 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
834 struct inode *inode, u64 start, u64 end)
835 {
836 struct btrfs_root *root = BTRFS_I(inode)->root;
837 struct extent_buffer *leaf;
838 struct btrfs_path *path;
839 struct btrfs_file_extent_item *fi;
840 struct btrfs_key key;
841 struct btrfs_key new_key;
842 u64 bytenr;
843 u64 num_bytes;
844 u64 extent_end;
845 u64 orig_offset;
846 u64 other_start;
847 u64 other_end;
848 u64 split;
849 int del_nr = 0;
850 int del_slot = 0;
851 int recow;
852 int ret;
853 u64 ino = btrfs_ino(inode);
854
855 btrfs_drop_extent_cache(inode, start, end - 1, 0);
856
857 path = btrfs_alloc_path();
858 BUG_ON(!path);
859 again:
860 recow = 0;
861 split = start;
862 key.objectid = ino;
863 key.type = BTRFS_EXTENT_DATA_KEY;
864 key.offset = split;
865
866 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
867 if (ret < 0)
868 goto out;
869 if (ret > 0 && path->slots[0] > 0)
870 path->slots[0]--;
871
872 leaf = path->nodes[0];
873 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
874 BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
875 fi = btrfs_item_ptr(leaf, path->slots[0],
876 struct btrfs_file_extent_item);
877 BUG_ON(btrfs_file_extent_type(leaf, fi) !=
878 BTRFS_FILE_EXTENT_PREALLOC);
879 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
880 BUG_ON(key.offset > start || extent_end < end);
881
882 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
883 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
884 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
885 memcpy(&new_key, &key, sizeof(new_key));
886
887 if (start == key.offset && end < extent_end) {
888 other_start = 0;
889 other_end = start;
890 if (extent_mergeable(leaf, path->slots[0] - 1,
891 ino, bytenr, orig_offset,
892 &other_start, &other_end)) {
893 new_key.offset = end;
894 btrfs_set_item_key_safe(trans, root, path, &new_key);
895 fi = btrfs_item_ptr(leaf, path->slots[0],
896 struct btrfs_file_extent_item);
897 btrfs_set_file_extent_num_bytes(leaf, fi,
898 extent_end - end);
899 btrfs_set_file_extent_offset(leaf, fi,
900 end - orig_offset);
901 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
902 struct btrfs_file_extent_item);
903 btrfs_set_file_extent_num_bytes(leaf, fi,
904 end - other_start);
905 btrfs_mark_buffer_dirty(leaf);
906 goto out;
907 }
908 }
909
910 if (start > key.offset && end == extent_end) {
911 other_start = end;
912 other_end = 0;
913 if (extent_mergeable(leaf, path->slots[0] + 1,
914 ino, bytenr, orig_offset,
915 &other_start, &other_end)) {
916 fi = btrfs_item_ptr(leaf, path->slots[0],
917 struct btrfs_file_extent_item);
918 btrfs_set_file_extent_num_bytes(leaf, fi,
919 start - key.offset);
920 path->slots[0]++;
921 new_key.offset = start;
922 btrfs_set_item_key_safe(trans, root, path, &new_key);
923
924 fi = btrfs_item_ptr(leaf, path->slots[0],
925 struct btrfs_file_extent_item);
926 btrfs_set_file_extent_num_bytes(leaf, fi,
927 other_end - start);
928 btrfs_set_file_extent_offset(leaf, fi,
929 start - orig_offset);
930 btrfs_mark_buffer_dirty(leaf);
931 goto out;
932 }
933 }
934
935 while (start > key.offset || end < extent_end) {
936 if (key.offset == start)
937 split = end;
938
939 new_key.offset = split;
940 ret = btrfs_duplicate_item(trans, root, path, &new_key);
941 if (ret == -EAGAIN) {
942 btrfs_release_path(path);
943 goto again;
944 }
945 BUG_ON(ret < 0);
946
947 leaf = path->nodes[0];
948 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
949 struct btrfs_file_extent_item);
950 btrfs_set_file_extent_num_bytes(leaf, fi,
951 split - key.offset);
952
953 fi = btrfs_item_ptr(leaf, path->slots[0],
954 struct btrfs_file_extent_item);
955
956 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
957 btrfs_set_file_extent_num_bytes(leaf, fi,
958 extent_end - split);
959 btrfs_mark_buffer_dirty(leaf);
960
961 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
962 root->root_key.objectid,
963 ino, orig_offset);
964 BUG_ON(ret);
965
966 if (split == start) {
967 key.offset = start;
968 } else {
969 BUG_ON(start != key.offset);
970 path->slots[0]--;
971 extent_end = end;
972 }
973 recow = 1;
974 }
975
976 other_start = end;
977 other_end = 0;
978 if (extent_mergeable(leaf, path->slots[0] + 1,
979 ino, bytenr, orig_offset,
980 &other_start, &other_end)) {
981 if (recow) {
982 btrfs_release_path(path);
983 goto again;
984 }
985 extent_end = other_end;
986 del_slot = path->slots[0] + 1;
987 del_nr++;
988 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
989 0, root->root_key.objectid,
990 ino, orig_offset);
991 BUG_ON(ret);
992 }
993 other_start = 0;
994 other_end = start;
995 if (extent_mergeable(leaf, path->slots[0] - 1,
996 ino, bytenr, orig_offset,
997 &other_start, &other_end)) {
998 if (recow) {
999 btrfs_release_path(path);
1000 goto again;
1001 }
1002 key.offset = other_start;
1003 del_slot = path->slots[0];
1004 del_nr++;
1005 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1006 0, root->root_key.objectid,
1007 ino, orig_offset);
1008 BUG_ON(ret);
1009 }
1010 if (del_nr == 0) {
1011 fi = btrfs_item_ptr(leaf, path->slots[0],
1012 struct btrfs_file_extent_item);
1013 btrfs_set_file_extent_type(leaf, fi,
1014 BTRFS_FILE_EXTENT_REG);
1015 btrfs_mark_buffer_dirty(leaf);
1016 } else {
1017 fi = btrfs_item_ptr(leaf, del_slot - 1,
1018 struct btrfs_file_extent_item);
1019 btrfs_set_file_extent_type(leaf, fi,
1020 BTRFS_FILE_EXTENT_REG);
1021 btrfs_set_file_extent_num_bytes(leaf, fi,
1022 extent_end - key.offset);
1023 btrfs_mark_buffer_dirty(leaf);
1024
1025 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1026 BUG_ON(ret);
1027 }
1028 out:
1029 btrfs_free_path(path);
1030 return 0;
1031 }
1032
1033 /*
1034 * on error we return an unlocked page and the error value
1035 * on success we return a locked page and 0
1036 */
1037 static int prepare_uptodate_page(struct page *page, u64 pos)
1038 {
1039 int ret = 0;
1040
1041 if ((pos & (PAGE_CACHE_SIZE - 1)) && !PageUptodate(page)) {
1042 ret = btrfs_readpage(NULL, page);
1043 if (ret)
1044 return ret;
1045 lock_page(page);
1046 if (!PageUptodate(page)) {
1047 unlock_page(page);
1048 return -EIO;
1049 }
1050 }
1051 return 0;
1052 }
1053
1054 /*
1055 * this gets pages into the page cache and locks them down, it also properly
1056 * waits for data=ordered extents to finish before allowing the pages to be
1057 * modified.
1058 */
1059 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
1060 struct page **pages, size_t num_pages,
1061 loff_t pos, unsigned long first_index,
1062 unsigned long last_index, size_t write_bytes)
1063 {
1064 struct extent_state *cached_state = NULL;
1065 int i;
1066 unsigned long index = pos >> PAGE_CACHE_SHIFT;
1067 struct inode *inode = fdentry(file)->d_inode;
1068 int err = 0;
1069 int faili = 0;
1070 u64 start_pos;
1071 u64 last_pos;
1072
1073 start_pos = pos & ~((u64)root->sectorsize - 1);
1074 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
1075
1076 if (start_pos > inode->i_size) {
1077 err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
1078 if (err)
1079 return err;
1080 }
1081
1082 again:
1083 for (i = 0; i < num_pages; i++) {
1084 pages[i] = grab_cache_page(inode->i_mapping, index + i);
1085 if (!pages[i]) {
1086 faili = i - 1;
1087 err = -ENOMEM;
1088 goto fail;
1089 }
1090
1091 if (i == 0)
1092 err = prepare_uptodate_page(pages[i], pos);
1093 if (i == num_pages - 1)
1094 err = prepare_uptodate_page(pages[i],
1095 pos + write_bytes);
1096 if (err) {
1097 page_cache_release(pages[i]);
1098 faili = i - 1;
1099 goto fail;
1100 }
1101 wait_on_page_writeback(pages[i]);
1102 }
1103 err = 0;
1104 if (start_pos < inode->i_size) {
1105 struct btrfs_ordered_extent *ordered;
1106 lock_extent_bits(&BTRFS_I(inode)->io_tree,
1107 start_pos, last_pos - 1, 0, &cached_state,
1108 GFP_NOFS);
1109 ordered = btrfs_lookup_first_ordered_extent(inode,
1110 last_pos - 1);
1111 if (ordered &&
1112 ordered->file_offset + ordered->len > start_pos &&
1113 ordered->file_offset < last_pos) {
1114 btrfs_put_ordered_extent(ordered);
1115 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1116 start_pos, last_pos - 1,
1117 &cached_state, GFP_NOFS);
1118 for (i = 0; i < num_pages; i++) {
1119 unlock_page(pages[i]);
1120 page_cache_release(pages[i]);
1121 }
1122 btrfs_wait_ordered_range(inode, start_pos,
1123 last_pos - start_pos);
1124 goto again;
1125 }
1126 if (ordered)
1127 btrfs_put_ordered_extent(ordered);
1128
1129 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
1130 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1131 EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
1132 GFP_NOFS);
1133 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1134 start_pos, last_pos - 1, &cached_state,
1135 GFP_NOFS);
1136 }
1137 for (i = 0; i < num_pages; i++) {
1138 clear_page_dirty_for_io(pages[i]);
1139 set_page_extent_mapped(pages[i]);
1140 WARN_ON(!PageLocked(pages[i]));
1141 }
1142 return 0;
1143 fail:
1144 while (faili >= 0) {
1145 unlock_page(pages[faili]);
1146 page_cache_release(pages[faili]);
1147 faili--;
1148 }
1149 return err;
1150
1151 }
1152
1153 static noinline ssize_t __btrfs_buffered_write(struct file *file,
1154 struct iov_iter *i,
1155 loff_t pos)
1156 {
1157 struct inode *inode = fdentry(file)->d_inode;
1158 struct btrfs_root *root = BTRFS_I(inode)->root;
1159 struct page **pages = NULL;
1160 unsigned long first_index;
1161 unsigned long last_index;
1162 size_t num_written = 0;
1163 int nrptrs;
1164 int ret = 0;
1165
1166 nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
1167 PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
1168 (sizeof(struct page *)));
1169 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1170 if (!pages)
1171 return -ENOMEM;
1172
1173 first_index = pos >> PAGE_CACHE_SHIFT;
1174 last_index = (pos + iov_iter_count(i)) >> PAGE_CACHE_SHIFT;
1175
1176 while (iov_iter_count(i) > 0) {
1177 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1178 size_t write_bytes = min(iov_iter_count(i),
1179 nrptrs * (size_t)PAGE_CACHE_SIZE -
1180 offset);
1181 size_t num_pages = (write_bytes + offset +
1182 PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1183 size_t dirty_pages;
1184 size_t copied;
1185
1186 WARN_ON(num_pages > nrptrs);
1187
1188 /*
1189 * Fault pages before locking them in prepare_pages
1190 * to avoid recursive lock
1191 */
1192 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1193 ret = -EFAULT;
1194 break;
1195 }
1196
1197 ret = btrfs_delalloc_reserve_space(inode,
1198 num_pages << PAGE_CACHE_SHIFT);
1199 if (ret)
1200 break;
1201
1202 /*
1203 * This is going to setup the pages array with the number of
1204 * pages we want, so we don't really need to worry about the
1205 * contents of pages from loop to loop
1206 */
1207 ret = prepare_pages(root, file, pages, num_pages,
1208 pos, first_index, last_index,
1209 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 atomic_inc(
1243 &BTRFS_I(inode)->outstanding_extents);
1244 btrfs_delalloc_release_space(inode,
1245 (num_pages - dirty_pages) <<
1246 PAGE_CACHE_SHIFT);
1247 }
1248
1249 if (copied > 0) {
1250 ret = btrfs_dirty_pages(root, inode, pages,
1251 dirty_pages, pos, copied,
1252 NULL);
1253 if (ret) {
1254 btrfs_delalloc_release_space(inode,
1255 dirty_pages << PAGE_CACHE_SHIFT);
1256 btrfs_drop_pages(pages, num_pages);
1257 break;
1258 }
1259 }
1260
1261 btrfs_drop_pages(pages, num_pages);
1262
1263 cond_resched();
1264
1265 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1266 dirty_pages);
1267 if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1268 btrfs_btree_balance_dirty(root, 1);
1269 btrfs_throttle(root);
1270
1271 pos += copied;
1272 num_written += copied;
1273 }
1274
1275 kfree(pages);
1276
1277 return num_written ? num_written : ret;
1278 }
1279
1280 static ssize_t __btrfs_direct_write(struct kiocb *iocb,
1281 const struct iovec *iov,
1282 unsigned long nr_segs, loff_t pos,
1283 loff_t *ppos, size_t count, size_t ocount)
1284 {
1285 struct file *file = iocb->ki_filp;
1286 struct inode *inode = fdentry(file)->d_inode;
1287 struct iov_iter i;
1288 ssize_t written;
1289 ssize_t written_buffered;
1290 loff_t endbyte;
1291 int err;
1292
1293 written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
1294 count, ocount);
1295
1296 /*
1297 * the generic O_DIRECT will update in-memory i_size after the
1298 * DIOs are done. But our endio handlers that update the on
1299 * disk i_size never update past the in memory i_size. So we
1300 * need one more update here to catch any additions to the
1301 * file
1302 */
1303 if (inode->i_size != BTRFS_I(inode)->disk_i_size) {
1304 btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
1305 mark_inode_dirty(inode);
1306 }
1307
1308 if (written < 0 || written == count)
1309 return written;
1310
1311 pos += written;
1312 count -= written;
1313 iov_iter_init(&i, iov, nr_segs, count, written);
1314 written_buffered = __btrfs_buffered_write(file, &i, pos);
1315 if (written_buffered < 0) {
1316 err = written_buffered;
1317 goto out;
1318 }
1319 endbyte = pos + written_buffered - 1;
1320 err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
1321 if (err)
1322 goto out;
1323 written += written_buffered;
1324 *ppos = pos + written_buffered;
1325 invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
1326 endbyte >> PAGE_CACHE_SHIFT);
1327 out:
1328 return written ? written : err;
1329 }
1330
1331 static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
1332 const struct iovec *iov,
1333 unsigned long nr_segs, loff_t pos)
1334 {
1335 struct file *file = iocb->ki_filp;
1336 struct inode *inode = fdentry(file)->d_inode;
1337 struct btrfs_root *root = BTRFS_I(inode)->root;
1338 loff_t *ppos = &iocb->ki_pos;
1339 ssize_t num_written = 0;
1340 ssize_t err = 0;
1341 size_t count, ocount;
1342
1343 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
1344
1345 mutex_lock(&inode->i_mutex);
1346
1347 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1348 if (err) {
1349 mutex_unlock(&inode->i_mutex);
1350 goto out;
1351 }
1352 count = ocount;
1353
1354 current->backing_dev_info = inode->i_mapping->backing_dev_info;
1355 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1356 if (err) {
1357 mutex_unlock(&inode->i_mutex);
1358 goto out;
1359 }
1360
1361 if (count == 0) {
1362 mutex_unlock(&inode->i_mutex);
1363 goto out;
1364 }
1365
1366 err = file_remove_suid(file);
1367 if (err) {
1368 mutex_unlock(&inode->i_mutex);
1369 goto out;
1370 }
1371
1372 /*
1373 * If BTRFS flips readonly due to some impossible error
1374 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1375 * although we have opened a file as writable, we have
1376 * to stop this write operation to ensure FS consistency.
1377 */
1378 if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
1379 mutex_unlock(&inode->i_mutex);
1380 err = -EROFS;
1381 goto out;
1382 }
1383
1384 file_update_time(file);
1385 BTRFS_I(inode)->sequence++;
1386
1387 if (unlikely(file->f_flags & O_DIRECT)) {
1388 num_written = __btrfs_direct_write(iocb, iov, nr_segs,
1389 pos, ppos, count, ocount);
1390 } else {
1391 struct iov_iter i;
1392
1393 iov_iter_init(&i, iov, nr_segs, count, num_written);
1394
1395 num_written = __btrfs_buffered_write(file, &i, pos);
1396 if (num_written > 0)
1397 *ppos = pos + num_written;
1398 }
1399
1400 mutex_unlock(&inode->i_mutex);
1401
1402 /*
1403 * we want to make sure fsync finds this change
1404 * but we haven't joined a transaction running right now.
1405 *
1406 * Later on, someone is sure to update the inode and get the
1407 * real transid recorded.
1408 *
1409 * We set last_trans now to the fs_info generation + 1,
1410 * this will either be one more than the running transaction
1411 * or the generation used for the next transaction if there isn't
1412 * one running right now.
1413 */
1414 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1415 if (num_written > 0 || num_written == -EIOCBQUEUED) {
1416 err = generic_write_sync(file, pos, num_written);
1417 if (err < 0 && num_written > 0)
1418 num_written = err;
1419 }
1420 out:
1421 current->backing_dev_info = NULL;
1422 return num_written ? num_written : err;
1423 }
1424
1425 int btrfs_release_file(struct inode *inode, struct file *filp)
1426 {
1427 /*
1428 * ordered_data_close is set by settattr when we are about to truncate
1429 * a file from a non-zero size to a zero size. This tries to
1430 * flush down new bytes that may have been written if the
1431 * application were using truncate to replace a file in place.
1432 */
1433 if (BTRFS_I(inode)->ordered_data_close) {
1434 BTRFS_I(inode)->ordered_data_close = 0;
1435 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1436 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1437 filemap_flush(inode->i_mapping);
1438 }
1439 if (filp->private_data)
1440 btrfs_ioctl_trans_end(filp);
1441 return 0;
1442 }
1443
1444 /*
1445 * fsync call for both files and directories. This logs the inode into
1446 * the tree log instead of forcing full commits whenever possible.
1447 *
1448 * It needs to call filemap_fdatawait so that all ordered extent updates are
1449 * in the metadata btree are up to date for copying to the log.
1450 *
1451 * It drops the inode mutex before doing the tree log commit. This is an
1452 * important optimization for directories because holding the mutex prevents
1453 * new operations on the dir while we write to disk.
1454 */
1455 int btrfs_sync_file(struct file *file, int datasync)
1456 {
1457 struct dentry *dentry = file->f_path.dentry;
1458 struct inode *inode = dentry->d_inode;
1459 struct btrfs_root *root = BTRFS_I(inode)->root;
1460 int ret = 0;
1461 struct btrfs_trans_handle *trans;
1462
1463 trace_btrfs_sync_file(file, datasync);
1464
1465 /* we wait first, since the writeback may change the inode */
1466 root->log_batch++;
1467 /* the VFS called filemap_fdatawrite for us */
1468 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1469 root->log_batch++;
1470
1471 /*
1472 * check the transaction that last modified this inode
1473 * and see if its already been committed
1474 */
1475 if (!BTRFS_I(inode)->last_trans)
1476 goto out;
1477
1478 /*
1479 * if the last transaction that changed this file was before
1480 * the current transaction, we can bail out now without any
1481 * syncing
1482 */
1483 smp_mb();
1484 if (BTRFS_I(inode)->last_trans <=
1485 root->fs_info->last_trans_committed) {
1486 BTRFS_I(inode)->last_trans = 0;
1487 goto out;
1488 }
1489
1490 /*
1491 * ok we haven't committed the transaction yet, lets do a commit
1492 */
1493 if (file->private_data)
1494 btrfs_ioctl_trans_end(file);
1495
1496 trans = btrfs_start_transaction(root, 0);
1497 if (IS_ERR(trans)) {
1498 ret = PTR_ERR(trans);
1499 goto out;
1500 }
1501
1502 ret = btrfs_log_dentry_safe(trans, root, dentry);
1503 if (ret < 0)
1504 goto out;
1505
1506 /* we've logged all the items and now have a consistent
1507 * version of the file in the log. It is possible that
1508 * someone will come in and modify the file, but that's
1509 * fine because the log is consistent on disk, and we
1510 * have references to all of the file's extents
1511 *
1512 * It is possible that someone will come in and log the
1513 * file again, but that will end up using the synchronization
1514 * inside btrfs_sync_log to keep things safe.
1515 */
1516 mutex_unlock(&dentry->d_inode->i_mutex);
1517
1518 if (ret != BTRFS_NO_LOG_SYNC) {
1519 if (ret > 0) {
1520 ret = btrfs_commit_transaction(trans, root);
1521 } else {
1522 ret = btrfs_sync_log(trans, root);
1523 if (ret == 0)
1524 ret = btrfs_end_transaction(trans, root);
1525 else
1526 ret = btrfs_commit_transaction(trans, root);
1527 }
1528 } else {
1529 ret = btrfs_end_transaction(trans, root);
1530 }
1531 mutex_lock(&dentry->d_inode->i_mutex);
1532 out:
1533 return ret > 0 ? -EIO : ret;
1534 }
1535
1536 static const struct vm_operations_struct btrfs_file_vm_ops = {
1537 .fault = filemap_fault,
1538 .page_mkwrite = btrfs_page_mkwrite,
1539 };
1540
1541 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1542 {
1543 struct address_space *mapping = filp->f_mapping;
1544
1545 if (!mapping->a_ops->readpage)
1546 return -ENOEXEC;
1547
1548 file_accessed(filp);
1549 vma->vm_ops = &btrfs_file_vm_ops;
1550 vma->vm_flags |= VM_CAN_NONLINEAR;
1551
1552 return 0;
1553 }
1554
1555 static long btrfs_fallocate(struct file *file, int mode,
1556 loff_t offset, loff_t len)
1557 {
1558 struct inode *inode = file->f_path.dentry->d_inode;
1559 struct extent_state *cached_state = NULL;
1560 u64 cur_offset;
1561 u64 last_byte;
1562 u64 alloc_start;
1563 u64 alloc_end;
1564 u64 alloc_hint = 0;
1565 u64 locked_end;
1566 u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
1567 struct extent_map *em;
1568 int ret;
1569
1570 alloc_start = offset & ~mask;
1571 alloc_end = (offset + len + mask) & ~mask;
1572
1573 /* We only support the FALLOC_FL_KEEP_SIZE mode */
1574 if (mode & ~FALLOC_FL_KEEP_SIZE)
1575 return -EOPNOTSUPP;
1576
1577 /*
1578 * wait for ordered IO before we have any locks. We'll loop again
1579 * below with the locks held.
1580 */
1581 btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
1582
1583 mutex_lock(&inode->i_mutex);
1584 ret = inode_newsize_ok(inode, alloc_end);
1585 if (ret)
1586 goto out;
1587
1588 if (alloc_start > inode->i_size) {
1589 ret = btrfs_cont_expand(inode, i_size_read(inode),
1590 alloc_start);
1591 if (ret)
1592 goto out;
1593 }
1594
1595 ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
1596 if (ret)
1597 goto out;
1598
1599 locked_end = alloc_end - 1;
1600 while (1) {
1601 struct btrfs_ordered_extent *ordered;
1602
1603 /* the extent lock is ordered inside the running
1604 * transaction
1605 */
1606 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
1607 locked_end, 0, &cached_state, GFP_NOFS);
1608 ordered = btrfs_lookup_first_ordered_extent(inode,
1609 alloc_end - 1);
1610 if (ordered &&
1611 ordered->file_offset + ordered->len > alloc_start &&
1612 ordered->file_offset < alloc_end) {
1613 btrfs_put_ordered_extent(ordered);
1614 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1615 alloc_start, locked_end,
1616 &cached_state, GFP_NOFS);
1617 /*
1618 * we can't wait on the range with the transaction
1619 * running or with the extent lock held
1620 */
1621 btrfs_wait_ordered_range(inode, alloc_start,
1622 alloc_end - alloc_start);
1623 } else {
1624 if (ordered)
1625 btrfs_put_ordered_extent(ordered);
1626 break;
1627 }
1628 }
1629
1630 cur_offset = alloc_start;
1631 while (1) {
1632 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
1633 alloc_end - cur_offset, 0);
1634 BUG_ON(IS_ERR_OR_NULL(em));
1635 last_byte = min(extent_map_end(em), alloc_end);
1636 last_byte = (last_byte + mask) & ~mask;
1637 if (em->block_start == EXTENT_MAP_HOLE ||
1638 (cur_offset >= inode->i_size &&
1639 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
1640 ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
1641 last_byte - cur_offset,
1642 1 << inode->i_blkbits,
1643 offset + len,
1644 &alloc_hint);
1645 if (ret < 0) {
1646 free_extent_map(em);
1647 break;
1648 }
1649 }
1650 free_extent_map(em);
1651
1652 cur_offset = last_byte;
1653 if (cur_offset >= alloc_end) {
1654 ret = 0;
1655 break;
1656 }
1657 }
1658 unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
1659 &cached_state, GFP_NOFS);
1660
1661 btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
1662 out:
1663 mutex_unlock(&inode->i_mutex);
1664 return ret;
1665 }
1666
1667 const struct file_operations btrfs_file_operations = {
1668 .llseek = generic_file_llseek,
1669 .read = do_sync_read,
1670 .write = do_sync_write,
1671 .aio_read = generic_file_aio_read,
1672 .splice_read = generic_file_splice_read,
1673 .aio_write = btrfs_file_aio_write,
1674 .mmap = btrfs_file_mmap,
1675 .open = generic_file_open,
1676 .release = btrfs_release_file,
1677 .fsync = btrfs_sync_file,
1678 .fallocate = btrfs_fallocate,
1679 .unlocked_ioctl = btrfs_ioctl,
1680 #ifdef CONFIG_COMPAT
1681 .compat_ioctl = btrfs_ioctl,
1682 #endif
1683 };
CJK support for tty framebuffer vt