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Linux 2.6.31.6
[linux/fpc-iii.git] / fs / btrfs / file.c
blob4b833972273a75218eb775cf8caf64dc1be80ed7
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/swap.h>
28 #include <linux/writeback.h>
29 #include <linux/statfs.h>
30 #include <linux/compat.h>
31 #include "ctree.h"
32 #include "disk-io.h"
33 #include "transaction.h"
34 #include "btrfs_inode.h"
35 #include "ioctl.h"
36 #include "print-tree.h"
37 #include "tree-log.h"
38 #include "locking.h"
39 #include "compat.h"
40
41
42 /* simple helper to fault in pages and copy. This should go away
43 * and be replaced with calls into generic code.
44 */
45 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
46 int write_bytes,
47 struct page **prepared_pages,
48 const char __user *buf)
49 {
50 long page_fault = 0;
51 int i;
52 int offset = pos & (PAGE_CACHE_SIZE - 1);
53
54 for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
55 size_t count = min_t(size_t,
56 PAGE_CACHE_SIZE - offset, write_bytes);
57 struct page *page = prepared_pages[i];
58 fault_in_pages_readable(buf, count);
59
60 /* Copy data from userspace to the current page */
61 kmap(page);
62 page_fault = __copy_from_user(page_address(page) + offset,
63 buf, count);
64 /* Flush processor's dcache for this page */
65 flush_dcache_page(page);
66 kunmap(page);
67 buf += count;
68 write_bytes -= count;
69
70 if (page_fault)
71 break;
72 }
73 return page_fault ? -EFAULT : 0;
74 }
75
76 /*
77 * unlocks pages after btrfs_file_write is done with them
78 */
79 static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages)
80 {
81 size_t i;
82 for (i = 0; i < num_pages; i++) {
83 if (!pages[i])
84 break;
85 /* page checked is some magic around finding pages that
86 * have been modified without going through btrfs_set_page_dirty
87 * clear it here
88 */
89 ClearPageChecked(pages[i]);
90 unlock_page(pages[i]);
91 mark_page_accessed(pages[i]);
92 page_cache_release(pages[i]);
93 }
94 }
95
96 /*
97 * after copy_from_user, pages need to be dirtied and we need to make
98 * sure holes are created between the current EOF and the start of
99 * any next extents (if required).
100 *
101 * this also makes the decision about creating an inline extent vs
102 * doing real data extents, marking pages dirty and delalloc as required.
103 */
104 static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
105 struct btrfs_root *root,
106 struct file *file,
107 struct page **pages,
108 size_t num_pages,
109 loff_t pos,
110 size_t write_bytes)
111 {
112 int err = 0;
113 int i;
114 struct inode *inode = fdentry(file)->d_inode;
115 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
116 u64 hint_byte;
117 u64 num_bytes;
118 u64 start_pos;
119 u64 end_of_last_block;
120 u64 end_pos = pos + write_bytes;
121 loff_t isize = i_size_read(inode);
122
123 start_pos = pos & ~((u64)root->sectorsize - 1);
124 num_bytes = (write_bytes + pos - start_pos +
125 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
126
127 end_of_last_block = start_pos + num_bytes - 1;
128
129 lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
130 trans = btrfs_join_transaction(root, 1);
131 if (!trans) {
132 err = -ENOMEM;
133 goto out_unlock;
134 }
135 btrfs_set_trans_block_group(trans, inode);
136 hint_byte = 0;
137
138 set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
139
140 /* check for reserved extents on each page, we don't want
141 * to reset the delalloc bit on things that already have
142 * extents reserved.
143 */
144 btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
145 for (i = 0; i < num_pages; i++) {
146 struct page *p = pages[i];
147 SetPageUptodate(p);
148 ClearPageChecked(p);
149 set_page_dirty(p);
150 }
151 if (end_pos > isize) {
152 i_size_write(inode, end_pos);
153 /* we've only changed i_size in ram, and we haven't updated
154 * the disk i_size. There is no need to log the inode
155 * at this time.
156 */
157 }
158 err = btrfs_end_transaction(trans, root);
159 out_unlock:
160 unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
161 return err;
162 }
163
164 /*
165 * this drops all the extents in the cache that intersect the range
166 * [start, end]. Existing extents are split as required.
167 */
168 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
169 int skip_pinned)
170 {
171 struct extent_map *em;
172 struct extent_map *split = NULL;
173 struct extent_map *split2 = NULL;
174 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
175 u64 len = end - start + 1;
176 int ret;
177 int testend = 1;
178 unsigned long flags;
179 int compressed = 0;
180
181 WARN_ON(end < start);
182 if (end == (u64)-1) {
183 len = (u64)-1;
184 testend = 0;
185 }
186 while (1) {
187 if (!split)
188 split = alloc_extent_map(GFP_NOFS);
189 if (!split2)
190 split2 = alloc_extent_map(GFP_NOFS);
191
192 spin_lock(&em_tree->lock);
193 em = lookup_extent_mapping(em_tree, start, len);
194 if (!em) {
195 spin_unlock(&em_tree->lock);
196 break;
197 }
198 flags = em->flags;
199 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
200 spin_unlock(&em_tree->lock);
201 if (em->start <= start &&
202 (!testend || em->start + em->len >= start + len)) {
203 free_extent_map(em);
204 break;
205 }
206 if (start < em->start) {
207 len = em->start - start;
208 } else {
209 len = start + len - (em->start + em->len);
210 start = em->start + em->len;
211 }
212 free_extent_map(em);
213 continue;
214 }
215 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
216 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
217 remove_extent_mapping(em_tree, em);
218
219 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
220 em->start < start) {
221 split->start = em->start;
222 split->len = start - em->start;
223 split->orig_start = em->orig_start;
224 split->block_start = em->block_start;
225
226 if (compressed)
227 split->block_len = em->block_len;
228 else
229 split->block_len = split->len;
230
231 split->bdev = em->bdev;
232 split->flags = flags;
233 ret = add_extent_mapping(em_tree, split);
234 BUG_ON(ret);
235 free_extent_map(split);
236 split = split2;
237 split2 = NULL;
238 }
239 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
240 testend && em->start + em->len > start + len) {
241 u64 diff = start + len - em->start;
242
243 split->start = start + len;
244 split->len = em->start + em->len - (start + len);
245 split->bdev = em->bdev;
246 split->flags = flags;
247
248 if (compressed) {
249 split->block_len = em->block_len;
250 split->block_start = em->block_start;
251 split->orig_start = em->orig_start;
252 } else {
253 split->block_len = split->len;
254 split->block_start = em->block_start + diff;
255 split->orig_start = split->start;
256 }
257
258 ret = add_extent_mapping(em_tree, split);
259 BUG_ON(ret);
260 free_extent_map(split);
261 split = NULL;
262 }
263 spin_unlock(&em_tree->lock);
264
265 /* once for us */
266 free_extent_map(em);
267 /* once for the tree*/
268 free_extent_map(em);
269 }
270 if (split)
271 free_extent_map(split);
272 if (split2)
273 free_extent_map(split2);
274 return 0;
275 }
276
277 /*
278 * this is very complex, but the basic idea is to drop all extents
279 * in the range start - end. hint_block is filled in with a block number
280 * that would be a good hint to the block allocator for this file.
281 *
282 * If an extent intersects the range but is not entirely inside the range
283 * it is either truncated or split. Anything entirely inside the range
284 * is deleted from the tree.
285 *
286 * inline_limit is used to tell this code which offsets in the file to keep
287 * if they contain inline extents.
288 */
289 noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
290 struct btrfs_root *root, struct inode *inode,
291 u64 start, u64 end, u64 locked_end,
292 u64 inline_limit, u64 *hint_byte)
293 {
294 u64 extent_end = 0;
295 u64 search_start = start;
296 u64 ram_bytes = 0;
297 u64 disk_bytenr = 0;
298 u64 orig_locked_end = locked_end;
299 u8 compression;
300 u8 encryption;
301 u16 other_encoding = 0;
302 struct extent_buffer *leaf;
303 struct btrfs_file_extent_item *extent;
304 struct btrfs_path *path;
305 struct btrfs_key key;
306 struct btrfs_file_extent_item old;
307 int keep;
308 int slot;
309 int bookend;
310 int found_type = 0;
311 int found_extent;
312 int found_inline;
313 int recow;
314 int ret;
315
316 inline_limit = 0;
317 btrfs_drop_extent_cache(inode, start, end - 1, 0);
318
319 path = btrfs_alloc_path();
320 if (!path)
321 return -ENOMEM;
322 while (1) {
323 recow = 0;
324 btrfs_release_path(root, path);
325 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
326 search_start, -1);
327 if (ret < 0)
328 goto out;
329 if (ret > 0) {
330 if (path->slots[0] == 0) {
331 ret = 0;
332 goto out;
333 }
334 path->slots[0]--;
335 }
336 next_slot:
337 keep = 0;
338 bookend = 0;
339 found_extent = 0;
340 found_inline = 0;
341 compression = 0;
342 encryption = 0;
343 extent = NULL;
344 leaf = path->nodes[0];
345 slot = path->slots[0];
346 ret = 0;
347 btrfs_item_key_to_cpu(leaf, &key, slot);
348 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
349 key.offset >= end) {
350 goto out;
351 }
352 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
353 key.objectid != inode->i_ino) {
354 goto out;
355 }
356 if (recow) {
357 search_start = max(key.offset, start);
358 continue;
359 }
360 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
361 extent = btrfs_item_ptr(leaf, slot,
362 struct btrfs_file_extent_item);
363 found_type = btrfs_file_extent_type(leaf, extent);
364 compression = btrfs_file_extent_compression(leaf,
365 extent);
366 encryption = btrfs_file_extent_encryption(leaf,
367 extent);
368 other_encoding = btrfs_file_extent_other_encoding(leaf,
369 extent);
370 if (found_type == BTRFS_FILE_EXTENT_REG ||
371 found_type == BTRFS_FILE_EXTENT_PREALLOC) {
372 extent_end =
373 btrfs_file_extent_disk_bytenr(leaf,
374 extent);
375 if (extent_end)
376 *hint_byte = extent_end;
377
378 extent_end = key.offset +
379 btrfs_file_extent_num_bytes(leaf, extent);
380 ram_bytes = btrfs_file_extent_ram_bytes(leaf,
381 extent);
382 found_extent = 1;
383 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
384 found_inline = 1;
385 extent_end = key.offset +
386 btrfs_file_extent_inline_len(leaf, extent);
387 }
388 } else {
389 extent_end = search_start;
390 }
391
392 /* we found nothing we can drop */
393 if ((!found_extent && !found_inline) ||
394 search_start >= extent_end) {
395 int nextret;
396 u32 nritems;
397 nritems = btrfs_header_nritems(leaf);
398 if (slot >= nritems - 1) {
399 nextret = btrfs_next_leaf(root, path);
400 if (nextret)
401 goto out;
402 recow = 1;
403 } else {
404 path->slots[0]++;
405 }
406 goto next_slot;
407 }
408
409 if (end <= extent_end && start >= key.offset && found_inline)
410 *hint_byte = EXTENT_MAP_INLINE;
411
412 if (found_extent) {
413 read_extent_buffer(leaf, &old, (unsigned long)extent,
414 sizeof(old));
415 }
416
417 if (end < extent_end && end >= key.offset) {
418 bookend = 1;
419 if (found_inline && start <= key.offset)
420 keep = 1;
421 }
422
423 if (bookend && found_extent) {
424 if (locked_end < extent_end) {
425 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
426 locked_end, extent_end - 1,
427 GFP_NOFS);
428 if (!ret) {
429 btrfs_release_path(root, path);
430 lock_extent(&BTRFS_I(inode)->io_tree,
431 locked_end, extent_end - 1,
432 GFP_NOFS);
433 locked_end = extent_end;
434 continue;
435 }
436 locked_end = extent_end;
437 }
438 disk_bytenr = le64_to_cpu(old.disk_bytenr);
439 if (disk_bytenr != 0) {
440 ret = btrfs_inc_extent_ref(trans, root,
441 disk_bytenr,
442 le64_to_cpu(old.disk_num_bytes), 0,
443 root->root_key.objectid,
444 key.objectid, key.offset -
445 le64_to_cpu(old.offset));
446 BUG_ON(ret);
447 }
448 }
449
450 if (found_inline) {
451 u64 mask = root->sectorsize - 1;
452 search_start = (extent_end + mask) & ~mask;
453 } else
454 search_start = extent_end;
455
456 /* truncate existing extent */
457 if (start > key.offset) {
458 u64 new_num;
459 u64 old_num;
460 keep = 1;
461 WARN_ON(start & (root->sectorsize - 1));
462 if (found_extent) {
463 new_num = start - key.offset;
464 old_num = btrfs_file_extent_num_bytes(leaf,
465 extent);
466 *hint_byte =
467 btrfs_file_extent_disk_bytenr(leaf,
468 extent);
469 if (btrfs_file_extent_disk_bytenr(leaf,
470 extent)) {
471 inode_sub_bytes(inode, old_num -
472 new_num);
473 }
474 btrfs_set_file_extent_num_bytes(leaf,
475 extent, new_num);
476 btrfs_mark_buffer_dirty(leaf);
477 } else if (key.offset < inline_limit &&
478 (end > extent_end) &&
479 (inline_limit < extent_end)) {
480 u32 new_size;
481 new_size = btrfs_file_extent_calc_inline_size(
482 inline_limit - key.offset);
483 inode_sub_bytes(inode, extent_end -
484 inline_limit);
485 btrfs_set_file_extent_ram_bytes(leaf, extent,
486 new_size);
487 if (!compression && !encryption) {
488 btrfs_truncate_item(trans, root, path,
489 new_size, 1);
490 }
491 }
492 }
493 /* delete the entire extent */
494 if (!keep) {
495 if (found_inline)
496 inode_sub_bytes(inode, extent_end -
497 key.offset);
498 ret = btrfs_del_item(trans, root, path);
499 /* TODO update progress marker and return */
500 BUG_ON(ret);
501 extent = NULL;
502 btrfs_release_path(root, path);
503 /* the extent will be freed later */
504 }
505 if (bookend && found_inline && start <= key.offset) {
506 u32 new_size;
507 new_size = btrfs_file_extent_calc_inline_size(
508 extent_end - end);
509 inode_sub_bytes(inode, end - key.offset);
510 btrfs_set_file_extent_ram_bytes(leaf, extent,
511 new_size);
512 if (!compression && !encryption)
513 ret = btrfs_truncate_item(trans, root, path,
514 new_size, 0);
515 BUG_ON(ret);
516 }
517 /* create bookend, splitting the extent in two */
518 if (bookend && found_extent) {
519 struct btrfs_key ins;
520 ins.objectid = inode->i_ino;
521 ins.offset = end;
522 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
523
524 btrfs_release_path(root, path);
525 path->leave_spinning = 1;
526 ret = btrfs_insert_empty_item(trans, root, path, &ins,
527 sizeof(*extent));
528 BUG_ON(ret);
529
530 leaf = path->nodes[0];
531 extent = btrfs_item_ptr(leaf, path->slots[0],
532 struct btrfs_file_extent_item);
533 write_extent_buffer(leaf, &old,
534 (unsigned long)extent, sizeof(old));
535
536 btrfs_set_file_extent_compression(leaf, extent,
537 compression);
538 btrfs_set_file_extent_encryption(leaf, extent,
539 encryption);
540 btrfs_set_file_extent_other_encoding(leaf, extent,
541 other_encoding);
542 btrfs_set_file_extent_offset(leaf, extent,
543 le64_to_cpu(old.offset) + end - key.offset);
544 WARN_ON(le64_to_cpu(old.num_bytes) <
545 (extent_end - end));
546 btrfs_set_file_extent_num_bytes(leaf, extent,
547 extent_end - end);
548
549 /*
550 * set the ram bytes to the size of the full extent
551 * before splitting. This is a worst case flag,
552 * but its the best we can do because we don't know
553 * how splitting affects compression
554 */
555 btrfs_set_file_extent_ram_bytes(leaf, extent,
556 ram_bytes);
557 btrfs_set_file_extent_type(leaf, extent, found_type);
558
559 btrfs_unlock_up_safe(path, 1);
560 btrfs_mark_buffer_dirty(path->nodes[0]);
561 btrfs_set_lock_blocking(path->nodes[0]);
562
563 path->leave_spinning = 0;
564 btrfs_release_path(root, path);
565 if (disk_bytenr != 0)
566 inode_add_bytes(inode, extent_end - end);
567 }
568
569 if (found_extent && !keep) {
570 u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr);
571
572 if (old_disk_bytenr != 0) {
573 inode_sub_bytes(inode,
574 le64_to_cpu(old.num_bytes));
575 ret = btrfs_free_extent(trans, root,
576 old_disk_bytenr,
577 le64_to_cpu(old.disk_num_bytes),
578 0, root->root_key.objectid,
579 key.objectid, key.offset -
580 le64_to_cpu(old.offset));
581 BUG_ON(ret);
582 *hint_byte = old_disk_bytenr;
583 }
584 }
585
586 if (search_start >= end) {
587 ret = 0;
588 goto out;
589 }
590 }
591 out:
592 btrfs_free_path(path);
593 if (locked_end > orig_locked_end) {
594 unlock_extent(&BTRFS_I(inode)->io_tree, orig_locked_end,
595 locked_end - 1, GFP_NOFS);
596 }
597 return ret;
598 }
599
600 static int extent_mergeable(struct extent_buffer *leaf, int slot,
601 u64 objectid, u64 bytenr, u64 *start, u64 *end)
602 {
603 struct btrfs_file_extent_item *fi;
604 struct btrfs_key key;
605 u64 extent_end;
606
607 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
608 return 0;
609
610 btrfs_item_key_to_cpu(leaf, &key, slot);
611 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
612 return 0;
613
614 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
615 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
616 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
617 btrfs_file_extent_compression(leaf, fi) ||
618 btrfs_file_extent_encryption(leaf, fi) ||
619 btrfs_file_extent_other_encoding(leaf, fi))
620 return 0;
621
622 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
623 if ((*start && *start != key.offset) || (*end && *end != extent_end))
624 return 0;
625
626 *start = key.offset;
627 *end = extent_end;
628 return 1;
629 }
630
631 /*
632 * Mark extent in the range start - end as written.
633 *
634 * This changes extent type from 'pre-allocated' to 'regular'. If only
635 * part of extent is marked as written, the extent will be split into
636 * two or three.
637 */
638 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
639 struct btrfs_root *root,
640 struct inode *inode, u64 start, u64 end)
641 {
642 struct extent_buffer *leaf;
643 struct btrfs_path *path;
644 struct btrfs_file_extent_item *fi;
645 struct btrfs_key key;
646 u64 bytenr;
647 u64 num_bytes;
648 u64 extent_end;
649 u64 orig_offset;
650 u64 other_start;
651 u64 other_end;
652 u64 split = start;
653 u64 locked_end = end;
654 int extent_type;
655 int split_end = 1;
656 int ret;
657
658 btrfs_drop_extent_cache(inode, start, end - 1, 0);
659
660 path = btrfs_alloc_path();
661 BUG_ON(!path);
662 again:
663 key.objectid = inode->i_ino;
664 key.type = BTRFS_EXTENT_DATA_KEY;
665 if (split == start)
666 key.offset = split;
667 else
668 key.offset = split - 1;
669
670 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
671 if (ret > 0 && path->slots[0] > 0)
672 path->slots[0]--;
673
674 leaf = path->nodes[0];
675 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
676 BUG_ON(key.objectid != inode->i_ino ||
677 key.type != BTRFS_EXTENT_DATA_KEY);
678 fi = btrfs_item_ptr(leaf, path->slots[0],
679 struct btrfs_file_extent_item);
680 extent_type = btrfs_file_extent_type(leaf, fi);
681 BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC);
682 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
683 BUG_ON(key.offset > start || extent_end < end);
684
685 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
686 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
687 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
688
689 if (key.offset == start)
690 split = end;
691
692 if (key.offset == start && extent_end == end) {
693 int del_nr = 0;
694 int del_slot = 0;
695 other_start = end;
696 other_end = 0;
697 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
698 bytenr, &other_start, &other_end)) {
699 extent_end = other_end;
700 del_slot = path->slots[0] + 1;
701 del_nr++;
702 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
703 0, root->root_key.objectid,
704 inode->i_ino, orig_offset);
705 BUG_ON(ret);
706 }
707 other_start = 0;
708 other_end = start;
709 if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino,
710 bytenr, &other_start, &other_end)) {
711 key.offset = other_start;
712 del_slot = path->slots[0];
713 del_nr++;
714 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
715 0, root->root_key.objectid,
716 inode->i_ino, orig_offset);
717 BUG_ON(ret);
718 }
719 split_end = 0;
720 if (del_nr == 0) {
721 btrfs_set_file_extent_type(leaf, fi,
722 BTRFS_FILE_EXTENT_REG);
723 goto done;
724 }
725
726 fi = btrfs_item_ptr(leaf, del_slot - 1,
727 struct btrfs_file_extent_item);
728 btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
729 btrfs_set_file_extent_num_bytes(leaf, fi,
730 extent_end - key.offset);
731 btrfs_mark_buffer_dirty(leaf);
732
733 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
734 BUG_ON(ret);
735 goto release;
736 } else if (split == start) {
737 if (locked_end < extent_end) {
738 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
739 locked_end, extent_end - 1, GFP_NOFS);
740 if (!ret) {
741 btrfs_release_path(root, path);
742 lock_extent(&BTRFS_I(inode)->io_tree,
743 locked_end, extent_end - 1, GFP_NOFS);
744 locked_end = extent_end;
745 goto again;
746 }
747 locked_end = extent_end;
748 }
749 btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
750 } else {
751 BUG_ON(key.offset != start);
752 key.offset = split;
753 btrfs_set_file_extent_offset(leaf, fi, key.offset -
754 orig_offset);
755 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
756 btrfs_set_item_key_safe(trans, root, path, &key);
757 extent_end = split;
758 }
759
760 if (extent_end == end) {
761 split_end = 0;
762 extent_type = BTRFS_FILE_EXTENT_REG;
763 }
764 if (extent_end == end && split == start) {
765 other_start = end;
766 other_end = 0;
767 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
768 bytenr, &other_start, &other_end)) {
769 path->slots[0]++;
770 fi = btrfs_item_ptr(leaf, path->slots[0],
771 struct btrfs_file_extent_item);
772 key.offset = split;
773 btrfs_set_item_key_safe(trans, root, path, &key);
774 btrfs_set_file_extent_offset(leaf, fi, key.offset -
775 orig_offset);
776 btrfs_set_file_extent_num_bytes(leaf, fi,
777 other_end - split);
778 goto done;
779 }
780 }
781 if (extent_end == end && split == end) {
782 other_start = 0;
783 other_end = start;
784 if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino,
785 bytenr, &other_start, &other_end)) {
786 path->slots[0]--;
787 fi = btrfs_item_ptr(leaf, path->slots[0],
788 struct btrfs_file_extent_item);
789 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end -
790 other_start);
791 goto done;
792 }
793 }
794
795 btrfs_mark_buffer_dirty(leaf);
796
797 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
798 root->root_key.objectid,
799 inode->i_ino, orig_offset);
800 BUG_ON(ret);
801 btrfs_release_path(root, path);
802
803 key.offset = start;
804 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi));
805 BUG_ON(ret);
806
807 leaf = path->nodes[0];
808 fi = btrfs_item_ptr(leaf, path->slots[0],
809 struct btrfs_file_extent_item);
810 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
811 btrfs_set_file_extent_type(leaf, fi, extent_type);
812 btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr);
813 btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
814 btrfs_set_file_extent_offset(leaf, fi, key.offset - orig_offset);
815 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset);
816 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
817 btrfs_set_file_extent_compression(leaf, fi, 0);
818 btrfs_set_file_extent_encryption(leaf, fi, 0);
819 btrfs_set_file_extent_other_encoding(leaf, fi, 0);
820 done:
821 btrfs_mark_buffer_dirty(leaf);
822
823 release:
824 btrfs_release_path(root, path);
825 if (split_end && split == start) {
826 split = end;
827 goto again;
828 }
829 if (locked_end > end) {
830 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
831 GFP_NOFS);
832 }
833 btrfs_free_path(path);
834 return 0;
835 }
836
837 /*
838 * this gets pages into the page cache and locks them down, it also properly
839 * waits for data=ordered extents to finish before allowing the pages to be
840 * modified.
841 */
842 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
843 struct page **pages, size_t num_pages,
844 loff_t pos, unsigned long first_index,
845 unsigned long last_index, size_t write_bytes)
846 {
847 int i;
848 unsigned long index = pos >> PAGE_CACHE_SHIFT;
849 struct inode *inode = fdentry(file)->d_inode;
850 int err = 0;
851 u64 start_pos;
852 u64 last_pos;
853
854 start_pos = pos & ~((u64)root->sectorsize - 1);
855 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
856
857 if (start_pos > inode->i_size) {
858 err = btrfs_cont_expand(inode, start_pos);
859 if (err)
860 return err;
861 }
862
863 memset(pages, 0, num_pages * sizeof(struct page *));
864 again:
865 for (i = 0; i < num_pages; i++) {
866 pages[i] = grab_cache_page(inode->i_mapping, index + i);
867 if (!pages[i]) {
868 err = -ENOMEM;
869 BUG_ON(1);
870 }
871 wait_on_page_writeback(pages[i]);
872 }
873 if (start_pos < inode->i_size) {
874 struct btrfs_ordered_extent *ordered;
875 lock_extent(&BTRFS_I(inode)->io_tree,
876 start_pos, last_pos - 1, GFP_NOFS);
877 ordered = btrfs_lookup_first_ordered_extent(inode,
878 last_pos - 1);
879 if (ordered &&
880 ordered->file_offset + ordered->len > start_pos &&
881 ordered->file_offset < last_pos) {
882 btrfs_put_ordered_extent(ordered);
883 unlock_extent(&BTRFS_I(inode)->io_tree,
884 start_pos, last_pos - 1, GFP_NOFS);
885 for (i = 0; i < num_pages; i++) {
886 unlock_page(pages[i]);
887 page_cache_release(pages[i]);
888 }
889 btrfs_wait_ordered_range(inode, start_pos,
890 last_pos - start_pos);
891 goto again;
892 }
893 if (ordered)
894 btrfs_put_ordered_extent(ordered);
895
896 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
897 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
898 GFP_NOFS);
899 unlock_extent(&BTRFS_I(inode)->io_tree,
900 start_pos, last_pos - 1, GFP_NOFS);
901 }
902 for (i = 0; i < num_pages; i++) {
903 clear_page_dirty_for_io(pages[i]);
904 set_page_extent_mapped(pages[i]);
905 WARN_ON(!PageLocked(pages[i]));
906 }
907 return 0;
908 }
909
910 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
911 size_t count, loff_t *ppos)
912 {
913 loff_t pos;
914 loff_t start_pos;
915 ssize_t num_written = 0;
916 ssize_t err = 0;
917 int ret = 0;
918 struct inode *inode = fdentry(file)->d_inode;
919 struct btrfs_root *root = BTRFS_I(inode)->root;
920 struct page **pages = NULL;
921 int nrptrs;
922 struct page *pinned[2];
923 unsigned long first_index;
924 unsigned long last_index;
925 int will_write;
926
927 will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) ||
928 (file->f_flags & O_DIRECT));
929
930 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
931 PAGE_CACHE_SIZE / (sizeof(struct page *)));
932 pinned[0] = NULL;
933 pinned[1] = NULL;
934
935 pos = *ppos;
936 start_pos = pos;
937
938 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
939 current->backing_dev_info = inode->i_mapping->backing_dev_info;
940 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
941 if (err)
942 goto out_nolock;
943 if (count == 0)
944 goto out_nolock;
945
946 err = file_remove_suid(file);
947 if (err)
948 goto out_nolock;
949 file_update_time(file);
950
951 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
952
953 mutex_lock(&inode->i_mutex);
954 BTRFS_I(inode)->sequence++;
955 first_index = pos >> PAGE_CACHE_SHIFT;
956 last_index = (pos + count) >> PAGE_CACHE_SHIFT;
957
958 /*
959 * there are lots of better ways to do this, but this code
960 * makes sure the first and last page in the file range are
961 * up to date and ready for cow
962 */
963 if ((pos & (PAGE_CACHE_SIZE - 1))) {
964 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
965 if (!PageUptodate(pinned[0])) {
966 ret = btrfs_readpage(NULL, pinned[0]);
967 BUG_ON(ret);
968 wait_on_page_locked(pinned[0]);
969 } else {
970 unlock_page(pinned[0]);
971 }
972 }
973 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
974 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
975 if (!PageUptodate(pinned[1])) {
976 ret = btrfs_readpage(NULL, pinned[1]);
977 BUG_ON(ret);
978 wait_on_page_locked(pinned[1]);
979 } else {
980 unlock_page(pinned[1]);
981 }
982 }
983
984 while (count > 0) {
985 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
986 size_t write_bytes = min(count, nrptrs *
987 (size_t)PAGE_CACHE_SIZE -
988 offset);
989 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
990 PAGE_CACHE_SHIFT;
991
992 WARN_ON(num_pages > nrptrs);
993 memset(pages, 0, sizeof(struct page *) * nrptrs);
994
995 ret = btrfs_check_data_free_space(root, inode, write_bytes);
996 if (ret)
997 goto out;
998
999 ret = prepare_pages(root, file, pages, num_pages,
1000 pos, first_index, last_index,
1001 write_bytes);
1002 if (ret) {
1003 btrfs_free_reserved_data_space(root, inode,
1004 write_bytes);
1005 goto out;
1006 }
1007
1008 ret = btrfs_copy_from_user(pos, num_pages,
1009 write_bytes, pages, buf);
1010 if (ret) {
1011 btrfs_free_reserved_data_space(root, inode,
1012 write_bytes);
1013 btrfs_drop_pages(pages, num_pages);
1014 goto out;
1015 }
1016
1017 ret = dirty_and_release_pages(NULL, root, file, pages,
1018 num_pages, pos, write_bytes);
1019 btrfs_drop_pages(pages, num_pages);
1020 if (ret) {
1021 btrfs_free_reserved_data_space(root, inode,
1022 write_bytes);
1023 goto out;
1024 }
1025
1026 if (will_write) {
1027 btrfs_fdatawrite_range(inode->i_mapping, pos,
1028 pos + write_bytes - 1,
1029 WB_SYNC_ALL);
1030 } else {
1031 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1032 num_pages);
1033 if (num_pages <
1034 (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1035 btrfs_btree_balance_dirty(root, 1);
1036 btrfs_throttle(root);
1037 }
1038
1039 buf += write_bytes;
1040 count -= write_bytes;
1041 pos += write_bytes;
1042 num_written += write_bytes;
1043
1044 cond_resched();
1045 }
1046 out:
1047 mutex_unlock(&inode->i_mutex);
1048 if (ret)
1049 err = ret;
1050
1051 out_nolock:
1052 kfree(pages);
1053 if (pinned[0])
1054 page_cache_release(pinned[0]);
1055 if (pinned[1])
1056 page_cache_release(pinned[1]);
1057 *ppos = pos;
1058
1059 /*
1060 * we want to make sure fsync finds this change
1061 * but we haven't joined a transaction running right now.
1062 *
1063 * Later on, someone is sure to update the inode and get the
1064 * real transid recorded.
1065 *
1066 * We set last_trans now to the fs_info generation + 1,
1067 * this will either be one more than the running transaction
1068 * or the generation used for the next transaction if there isn't
1069 * one running right now.
1070 */
1071 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1072
1073 if (num_written > 0 && will_write) {
1074 struct btrfs_trans_handle *trans;
1075
1076 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1077 if (err)
1078 num_written = err;
1079
1080 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
1081 trans = btrfs_start_transaction(root, 1);
1082 ret = btrfs_log_dentry_safe(trans, root,
1083 file->f_dentry);
1084 if (ret == 0) {
1085 ret = btrfs_sync_log(trans, root);
1086 if (ret == 0)
1087 btrfs_end_transaction(trans, root);
1088 else
1089 btrfs_commit_transaction(trans, root);
1090 } else {
1091 btrfs_commit_transaction(trans, root);
1092 }
1093 }
1094 if (file->f_flags & O_DIRECT) {
1095 invalidate_mapping_pages(inode->i_mapping,
1096 start_pos >> PAGE_CACHE_SHIFT,
1097 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1098 }
1099 }
1100 current->backing_dev_info = NULL;
1101 return num_written ? num_written : err;
1102 }
1103
1104 int btrfs_release_file(struct inode *inode, struct file *filp)
1105 {
1106 /*
1107 * ordered_data_close is set by settattr when we are about to truncate
1108 * a file from a non-zero size to a zero size. This tries to
1109 * flush down new bytes that may have been written if the
1110 * application were using truncate to replace a file in place.
1111 */
1112 if (BTRFS_I(inode)->ordered_data_close) {
1113 BTRFS_I(inode)->ordered_data_close = 0;
1114 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1115 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1116 filemap_flush(inode->i_mapping);
1117 }
1118 if (filp->private_data)
1119 btrfs_ioctl_trans_end(filp);
1120 return 0;
1121 }
1122
1123 /*
1124 * fsync call for both files and directories. This logs the inode into
1125 * the tree log instead of forcing full commits whenever possible.
1126 *
1127 * It needs to call filemap_fdatawait so that all ordered extent updates are
1128 * in the metadata btree are up to date for copying to the log.
1129 *
1130 * It drops the inode mutex before doing the tree log commit. This is an
1131 * important optimization for directories because holding the mutex prevents
1132 * new operations on the dir while we write to disk.
1133 */
1134 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
1135 {
1136 struct inode *inode = dentry->d_inode;
1137 struct btrfs_root *root = BTRFS_I(inode)->root;
1138 int ret = 0;
1139 struct btrfs_trans_handle *trans;
1140
1141 /*
1142 * check the transaction that last modified this inode
1143 * and see if its already been committed
1144 */
1145 if (!BTRFS_I(inode)->last_trans)
1146 goto out;
1147
1148 mutex_lock(&root->fs_info->trans_mutex);
1149 if (BTRFS_I(inode)->last_trans <=
1150 root->fs_info->last_trans_committed) {
1151 BTRFS_I(inode)->last_trans = 0;
1152 mutex_unlock(&root->fs_info->trans_mutex);
1153 goto out;
1154 }
1155 mutex_unlock(&root->fs_info->trans_mutex);
1156
1157 root->log_batch++;
1158 filemap_fdatawrite(inode->i_mapping);
1159 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1160 root->log_batch++;
1161
1162 if (datasync && !(inode->i_state & I_DIRTY_PAGES))
1163 goto out;
1164 /*
1165 * ok we haven't committed the transaction yet, lets do a commit
1166 */
1167 if (file && file->private_data)
1168 btrfs_ioctl_trans_end(file);
1169
1170 trans = btrfs_start_transaction(root, 1);
1171 if (!trans) {
1172 ret = -ENOMEM;
1173 goto out;
1174 }
1175
1176 ret = btrfs_log_dentry_safe(trans, root, dentry);
1177 if (ret < 0)
1178 goto out;
1179
1180 /* we've logged all the items and now have a consistent
1181 * version of the file in the log. It is possible that
1182 * someone will come in and modify the file, but that's
1183 * fine because the log is consistent on disk, and we
1184 * have references to all of the file's extents
1185 *
1186 * It is possible that someone will come in and log the
1187 * file again, but that will end up using the synchronization
1188 * inside btrfs_sync_log to keep things safe.
1189 */
1190 mutex_unlock(&dentry->d_inode->i_mutex);
1191
1192 if (ret > 0) {
1193 ret = btrfs_commit_transaction(trans, root);
1194 } else {
1195 ret = btrfs_sync_log(trans, root);
1196 if (ret == 0)
1197 ret = btrfs_end_transaction(trans, root);
1198 else
1199 ret = btrfs_commit_transaction(trans, root);
1200 }
1201 mutex_lock(&dentry->d_inode->i_mutex);
1202 out:
1203 return ret > 0 ? EIO : ret;
1204 }
1205
1206 static struct vm_operations_struct btrfs_file_vm_ops = {
1207 .fault = filemap_fault,
1208 .page_mkwrite = btrfs_page_mkwrite,
1209 };
1210
1211 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1212 {
1213 vma->vm_ops = &btrfs_file_vm_ops;
1214 file_accessed(filp);
1215 return 0;
1216 }
1217
1218 struct file_operations btrfs_file_operations = {
1219 .llseek = generic_file_llseek,
1220 .read = do_sync_read,
1221 .aio_read = generic_file_aio_read,
1222 .splice_read = generic_file_splice_read,
1223 .write = btrfs_file_write,
1224 .mmap = btrfs_file_mmap,
1225 .open = generic_file_open,
1226 .release = btrfs_release_file,
1227 .fsync = btrfs_sync_file,
1228 .unlocked_ioctl = btrfs_ioctl,
1229 #ifdef CONFIG_COMPAT
1230 .compat_ioctl = btrfs_ioctl,
1231 #endif
1232 };
Linux with added FPC-III support