?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
On Tue, Nov 06, 2007 at 02:33:53AM -0800, akpm@linux-foundation.org wrote:
[mmotm.git] / fs / btrfs / file.c
blob87e6906024e08174919ba332e4d57a522c8216e8
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 u64 num_bytes;
116 u64 start_pos;
117 u64 end_of_last_block;
118 u64 end_pos = pos + write_bytes;
119 loff_t isize = i_size_read(inode);
120
121 start_pos = pos & ~((u64)root->sectorsize - 1);
122 num_bytes = (write_bytes + pos - start_pos +
123 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
124
125 end_of_last_block = start_pos + num_bytes - 1;
126 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
127 if (err)
128 return err;
129
130 for (i = 0; i < num_pages; i++) {
131 struct page *p = pages[i];
132 SetPageUptodate(p);
133 ClearPageChecked(p);
134 set_page_dirty(p);
135 }
136 if (end_pos > isize) {
137 i_size_write(inode, end_pos);
138 /* we've only changed i_size in ram, and we haven't updated
139 * the disk i_size. There is no need to log the inode
140 * at this time.
141 */
142 }
143 return err;
144 }
145
146 /*
147 * this drops all the extents in the cache that intersect the range
148 * [start, end]. Existing extents are split as required.
149 */
150 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
151 int skip_pinned)
152 {
153 struct extent_map *em;
154 struct extent_map *split = NULL;
155 struct extent_map *split2 = NULL;
156 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
157 u64 len = end - start + 1;
158 int ret;
159 int testend = 1;
160 unsigned long flags;
161 int compressed = 0;
162
163 WARN_ON(end < start);
164 if (end == (u64)-1) {
165 len = (u64)-1;
166 testend = 0;
167 }
168 while (1) {
169 if (!split)
170 split = alloc_extent_map(GFP_NOFS);
171 if (!split2)
172 split2 = alloc_extent_map(GFP_NOFS);
173
174 write_lock(&em_tree->lock);
175 em = lookup_extent_mapping(em_tree, start, len);
176 if (!em) {
177 write_unlock(&em_tree->lock);
178 break;
179 }
180 flags = em->flags;
181 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
182 if (em->start <= start &&
183 (!testend || em->start + em->len >= start + len)) {
184 free_extent_map(em);
185 write_unlock(&em_tree->lock);
186 break;
187 }
188 if (start < em->start) {
189 len = em->start - start;
190 } else {
191 len = start + len - (em->start + em->len);
192 start = em->start + em->len;
193 }
194 free_extent_map(em);
195 write_unlock(&em_tree->lock);
196 continue;
197 }
198 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
199 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
200 remove_extent_mapping(em_tree, em);
201
202 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
203 em->start < start) {
204 split->start = em->start;
205 split->len = start - em->start;
206 split->orig_start = em->orig_start;
207 split->block_start = em->block_start;
208
209 if (compressed)
210 split->block_len = em->block_len;
211 else
212 split->block_len = split->len;
213
214 split->bdev = em->bdev;
215 split->flags = flags;
216 ret = add_extent_mapping(em_tree, split);
217 BUG_ON(ret);
218 free_extent_map(split);
219 split = split2;
220 split2 = NULL;
221 }
222 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
223 testend && em->start + em->len > start + len) {
224 u64 diff = start + len - em->start;
225
226 split->start = start + len;
227 split->len = em->start + em->len - (start + len);
228 split->bdev = em->bdev;
229 split->flags = flags;
230
231 if (compressed) {
232 split->block_len = em->block_len;
233 split->block_start = em->block_start;
234 split->orig_start = em->orig_start;
235 } else {
236 split->block_len = split->len;
237 split->block_start = em->block_start + diff;
238 split->orig_start = split->start;
239 }
240
241 ret = add_extent_mapping(em_tree, split);
242 BUG_ON(ret);
243 free_extent_map(split);
244 split = NULL;
245 }
246 write_unlock(&em_tree->lock);
247
248 /* once for us */
249 free_extent_map(em);
250 /* once for the tree*/
251 free_extent_map(em);
252 }
253 if (split)
254 free_extent_map(split);
255 if (split2)
256 free_extent_map(split2);
257 return 0;
258 }
259
260 /*
261 * this is very complex, but the basic idea is to drop all extents
262 * in the range start - end. hint_block is filled in with a block number
263 * that would be a good hint to the block allocator for this file.
264 *
265 * If an extent intersects the range but is not entirely inside the range
266 * it is either truncated or split. Anything entirely inside the range
267 * is deleted from the tree.
268 *
269 * inline_limit is used to tell this code which offsets in the file to keep
270 * if they contain inline extents.
271 */
272 noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
273 struct btrfs_root *root, struct inode *inode,
274 u64 start, u64 end, u64 locked_end,
275 u64 inline_limit, u64 *hint_byte, int drop_cache)
276 {
277 u64 extent_end = 0;
278 u64 search_start = start;
279 u64 ram_bytes = 0;
280 u64 disk_bytenr = 0;
281 u64 orig_locked_end = locked_end;
282 u8 compression;
283 u8 encryption;
284 u16 other_encoding = 0;
285 struct extent_buffer *leaf;
286 struct btrfs_file_extent_item *extent;
287 struct btrfs_path *path;
288 struct btrfs_key key;
289 struct btrfs_file_extent_item old;
290 int keep;
291 int slot;
292 int bookend;
293 int found_type = 0;
294 int found_extent;
295 int found_inline;
296 int recow;
297 int ret;
298
299 inline_limit = 0;
300 if (drop_cache)
301 btrfs_drop_extent_cache(inode, start, end - 1, 0);
302
303 path = btrfs_alloc_path();
304 if (!path)
305 return -ENOMEM;
306 while (1) {
307 recow = 0;
308 btrfs_release_path(root, path);
309 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
310 search_start, -1);
311 if (ret < 0)
312 goto out;
313 if (ret > 0) {
314 if (path->slots[0] == 0) {
315 ret = 0;
316 goto out;
317 }
318 path->slots[0]--;
319 }
320 next_slot:
321 keep = 0;
322 bookend = 0;
323 found_extent = 0;
324 found_inline = 0;
325 compression = 0;
326 encryption = 0;
327 extent = NULL;
328 leaf = path->nodes[0];
329 slot = path->slots[0];
330 ret = 0;
331 btrfs_item_key_to_cpu(leaf, &key, slot);
332 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
333 key.offset >= end) {
334 goto out;
335 }
336 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
337 key.objectid != inode->i_ino) {
338 goto out;
339 }
340 if (recow) {
341 search_start = max(key.offset, start);
342 continue;
343 }
344 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
345 extent = btrfs_item_ptr(leaf, slot,
346 struct btrfs_file_extent_item);
347 found_type = btrfs_file_extent_type(leaf, extent);
348 compression = btrfs_file_extent_compression(leaf,
349 extent);
350 encryption = btrfs_file_extent_encryption(leaf,
351 extent);
352 other_encoding = btrfs_file_extent_other_encoding(leaf,
353 extent);
354 if (found_type == BTRFS_FILE_EXTENT_REG ||
355 found_type == BTRFS_FILE_EXTENT_PREALLOC) {
356 extent_end =
357 btrfs_file_extent_disk_bytenr(leaf,
358 extent);
359 if (extent_end)
360 *hint_byte = extent_end;
361
362 extent_end = key.offset +
363 btrfs_file_extent_num_bytes(leaf, extent);
364 ram_bytes = btrfs_file_extent_ram_bytes(leaf,
365 extent);
366 found_extent = 1;
367 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
368 found_inline = 1;
369 extent_end = key.offset +
370 btrfs_file_extent_inline_len(leaf, extent);
371 }
372 } else {
373 extent_end = search_start;
374 }
375
376 /* we found nothing we can drop */
377 if ((!found_extent && !found_inline) ||
378 search_start >= extent_end) {
379 int nextret;
380 u32 nritems;
381 nritems = btrfs_header_nritems(leaf);
382 if (slot >= nritems - 1) {
383 nextret = btrfs_next_leaf(root, path);
384 if (nextret)
385 goto out;
386 recow = 1;
387 } else {
388 path->slots[0]++;
389 }
390 goto next_slot;
391 }
392
393 if (end <= extent_end && start >= key.offset && found_inline)
394 *hint_byte = EXTENT_MAP_INLINE;
395
396 if (found_extent) {
397 read_extent_buffer(leaf, &old, (unsigned long)extent,
398 sizeof(old));
399 }
400
401 if (end < extent_end && end >= key.offset) {
402 bookend = 1;
403 if (found_inline && start <= key.offset)
404 keep = 1;
405 }
406
407 if (bookend && found_extent) {
408 if (locked_end < extent_end) {
409 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
410 locked_end, extent_end - 1,
411 GFP_NOFS);
412 if (!ret) {
413 btrfs_release_path(root, path);
414 lock_extent(&BTRFS_I(inode)->io_tree,
415 locked_end, extent_end - 1,
416 GFP_NOFS);
417 locked_end = extent_end;
418 continue;
419 }
420 locked_end = extent_end;
421 }
422 disk_bytenr = le64_to_cpu(old.disk_bytenr);
423 if (disk_bytenr != 0) {
424 ret = btrfs_inc_extent_ref(trans, root,
425 disk_bytenr,
426 le64_to_cpu(old.disk_num_bytes), 0,
427 root->root_key.objectid,
428 key.objectid, key.offset -
429 le64_to_cpu(old.offset));
430 BUG_ON(ret);
431 }
432 }
433
434 if (found_inline) {
435 u64 mask = root->sectorsize - 1;
436 search_start = (extent_end + mask) & ~mask;
437 } else
438 search_start = extent_end;
439
440 /* truncate existing extent */
441 if (start > key.offset) {
442 u64 new_num;
443 u64 old_num;
444 keep = 1;
445 WARN_ON(start & (root->sectorsize - 1));
446 if (found_extent) {
447 new_num = start - key.offset;
448 old_num = btrfs_file_extent_num_bytes(leaf,
449 extent);
450 *hint_byte =
451 btrfs_file_extent_disk_bytenr(leaf,
452 extent);
453 if (btrfs_file_extent_disk_bytenr(leaf,
454 extent)) {
455 inode_sub_bytes(inode, old_num -
456 new_num);
457 }
458 btrfs_set_file_extent_num_bytes(leaf,
459 extent, new_num);
460 btrfs_mark_buffer_dirty(leaf);
461 } else if (key.offset < inline_limit &&
462 (end > extent_end) &&
463 (inline_limit < extent_end)) {
464 u32 new_size;
465 new_size = btrfs_file_extent_calc_inline_size(
466 inline_limit - key.offset);
467 inode_sub_bytes(inode, extent_end -
468 inline_limit);
469 btrfs_set_file_extent_ram_bytes(leaf, extent,
470 new_size);
471 if (!compression && !encryption) {
472 btrfs_truncate_item(trans, root, path,
473 new_size, 1);
474 }
475 }
476 }
477 /* delete the entire extent */
478 if (!keep) {
479 if (found_inline)
480 inode_sub_bytes(inode, extent_end -
481 key.offset);
482 ret = btrfs_del_item(trans, root, path);
483 /* TODO update progress marker and return */
484 BUG_ON(ret);
485 extent = NULL;
486 btrfs_release_path(root, path);
487 /* the extent will be freed later */
488 }
489 if (bookend && found_inline && start <= key.offset) {
490 u32 new_size;
491 new_size = btrfs_file_extent_calc_inline_size(
492 extent_end - end);
493 inode_sub_bytes(inode, end - key.offset);
494 btrfs_set_file_extent_ram_bytes(leaf, extent,
495 new_size);
496 if (!compression && !encryption)
497 ret = btrfs_truncate_item(trans, root, path,
498 new_size, 0);
499 BUG_ON(ret);
500 }
501 /* create bookend, splitting the extent in two */
502 if (bookend && found_extent) {
503 struct btrfs_key ins;
504 ins.objectid = inode->i_ino;
505 ins.offset = end;
506 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
507
508 btrfs_release_path(root, path);
509 path->leave_spinning = 1;
510 ret = btrfs_insert_empty_item(trans, root, path, &ins,
511 sizeof(*extent));
512 BUG_ON(ret);
513
514 leaf = path->nodes[0];
515 extent = btrfs_item_ptr(leaf, path->slots[0],
516 struct btrfs_file_extent_item);
517 write_extent_buffer(leaf, &old,
518 (unsigned long)extent, sizeof(old));
519
520 btrfs_set_file_extent_compression(leaf, extent,
521 compression);
522 btrfs_set_file_extent_encryption(leaf, extent,
523 encryption);
524 btrfs_set_file_extent_other_encoding(leaf, extent,
525 other_encoding);
526 btrfs_set_file_extent_offset(leaf, extent,
527 le64_to_cpu(old.offset) + end - key.offset);
528 WARN_ON(le64_to_cpu(old.num_bytes) <
529 (extent_end - end));
530 btrfs_set_file_extent_num_bytes(leaf, extent,
531 extent_end - end);
532
533 /*
534 * set the ram bytes to the size of the full extent
535 * before splitting. This is a worst case flag,
536 * but its the best we can do because we don't know
537 * how splitting affects compression
538 */
539 btrfs_set_file_extent_ram_bytes(leaf, extent,
540 ram_bytes);
541 btrfs_set_file_extent_type(leaf, extent, found_type);
542
543 btrfs_unlock_up_safe(path, 1);
544 btrfs_mark_buffer_dirty(path->nodes[0]);
545 btrfs_set_lock_blocking(path->nodes[0]);
546
547 path->leave_spinning = 0;
548 btrfs_release_path(root, path);
549 if (disk_bytenr != 0)
550 inode_add_bytes(inode, extent_end - end);
551 }
552
553 if (found_extent && !keep) {
554 u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr);
555
556 if (old_disk_bytenr != 0) {
557 inode_sub_bytes(inode,
558 le64_to_cpu(old.num_bytes));
559 ret = btrfs_free_extent(trans, root,
560 old_disk_bytenr,
561 le64_to_cpu(old.disk_num_bytes),
562 0, root->root_key.objectid,
563 key.objectid, key.offset -
564 le64_to_cpu(old.offset));
565 BUG_ON(ret);
566 *hint_byte = old_disk_bytenr;
567 }
568 }
569
570 if (search_start >= end) {
571 ret = 0;
572 goto out;
573 }
574 }
575 out:
576 btrfs_free_path(path);
577 if (locked_end > orig_locked_end) {
578 unlock_extent(&BTRFS_I(inode)->io_tree, orig_locked_end,
579 locked_end - 1, GFP_NOFS);
580 }
581 return ret;
582 }
583
584 static int extent_mergeable(struct extent_buffer *leaf, int slot,
585 u64 objectid, u64 bytenr, u64 *start, u64 *end)
586 {
587 struct btrfs_file_extent_item *fi;
588 struct btrfs_key key;
589 u64 extent_end;
590
591 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
592 return 0;
593
594 btrfs_item_key_to_cpu(leaf, &key, slot);
595 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
596 return 0;
597
598 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
599 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
600 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
601 btrfs_file_extent_compression(leaf, fi) ||
602 btrfs_file_extent_encryption(leaf, fi) ||
603 btrfs_file_extent_other_encoding(leaf, fi))
604 return 0;
605
606 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
607 if ((*start && *start != key.offset) || (*end && *end != extent_end))
608 return 0;
609
610 *start = key.offset;
611 *end = extent_end;
612 return 1;
613 }
614
615 /*
616 * Mark extent in the range start - end as written.
617 *
618 * This changes extent type from 'pre-allocated' to 'regular'. If only
619 * part of extent is marked as written, the extent will be split into
620 * two or three.
621 */
622 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
623 struct btrfs_root *root,
624 struct inode *inode, u64 start, u64 end)
625 {
626 struct extent_buffer *leaf;
627 struct btrfs_path *path;
628 struct btrfs_file_extent_item *fi;
629 struct btrfs_key key;
630 u64 bytenr;
631 u64 num_bytes;
632 u64 extent_end;
633 u64 orig_offset;
634 u64 other_start;
635 u64 other_end;
636 u64 split = start;
637 u64 locked_end = end;
638 int extent_type;
639 int split_end = 1;
640 int ret;
641
642 btrfs_drop_extent_cache(inode, start, end - 1, 0);
643
644 path = btrfs_alloc_path();
645 BUG_ON(!path);
646 again:
647 key.objectid = inode->i_ino;
648 key.type = BTRFS_EXTENT_DATA_KEY;
649 if (split == start)
650 key.offset = split;
651 else
652 key.offset = split - 1;
653
654 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
655 if (ret > 0 && path->slots[0] > 0)
656 path->slots[0]--;
657
658 leaf = path->nodes[0];
659 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
660 BUG_ON(key.objectid != inode->i_ino ||
661 key.type != BTRFS_EXTENT_DATA_KEY);
662 fi = btrfs_item_ptr(leaf, path->slots[0],
663 struct btrfs_file_extent_item);
664 extent_type = btrfs_file_extent_type(leaf, fi);
665 BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC);
666 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
667 BUG_ON(key.offset > start || extent_end < end);
668
669 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
670 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
671 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
672
673 if (key.offset == start)
674 split = end;
675
676 if (key.offset == start && extent_end == end) {
677 int del_nr = 0;
678 int del_slot = 0;
679 other_start = end;
680 other_end = 0;
681 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
682 bytenr, &other_start, &other_end)) {
683 extent_end = other_end;
684 del_slot = path->slots[0] + 1;
685 del_nr++;
686 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
687 0, root->root_key.objectid,
688 inode->i_ino, orig_offset);
689 BUG_ON(ret);
690 }
691 other_start = 0;
692 other_end = start;
693 if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino,
694 bytenr, &other_start, &other_end)) {
695 key.offset = other_start;
696 del_slot = path->slots[0];
697 del_nr++;
698 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
699 0, root->root_key.objectid,
700 inode->i_ino, orig_offset);
701 BUG_ON(ret);
702 }
703 split_end = 0;
704 if (del_nr == 0) {
705 btrfs_set_file_extent_type(leaf, fi,
706 BTRFS_FILE_EXTENT_REG);
707 goto done;
708 }
709
710 fi = btrfs_item_ptr(leaf, del_slot - 1,
711 struct btrfs_file_extent_item);
712 btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
713 btrfs_set_file_extent_num_bytes(leaf, fi,
714 extent_end - key.offset);
715 btrfs_mark_buffer_dirty(leaf);
716
717 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
718 BUG_ON(ret);
719 goto release;
720 } else if (split == start) {
721 if (locked_end < extent_end) {
722 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
723 locked_end, extent_end - 1, GFP_NOFS);
724 if (!ret) {
725 btrfs_release_path(root, path);
726 lock_extent(&BTRFS_I(inode)->io_tree,
727 locked_end, extent_end - 1, GFP_NOFS);
728 locked_end = extent_end;
729 goto again;
730 }
731 locked_end = extent_end;
732 }
733 btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
734 } else {
735 BUG_ON(key.offset != start);
736 key.offset = split;
737 btrfs_set_file_extent_offset(leaf, fi, key.offset -
738 orig_offset);
739 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
740 btrfs_set_item_key_safe(trans, root, path, &key);
741 extent_end = split;
742 }
743
744 if (extent_end == end) {
745 split_end = 0;
746 extent_type = BTRFS_FILE_EXTENT_REG;
747 }
748 if (extent_end == end && split == start) {
749 other_start = end;
750 other_end = 0;
751 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
752 bytenr, &other_start, &other_end)) {
753 path->slots[0]++;
754 fi = btrfs_item_ptr(leaf, path->slots[0],
755 struct btrfs_file_extent_item);
756 key.offset = split;
757 btrfs_set_item_key_safe(trans, root, path, &key);
758 btrfs_set_file_extent_offset(leaf, fi, key.offset -
759 orig_offset);
760 btrfs_set_file_extent_num_bytes(leaf, fi,
761 other_end - split);
762 goto done;
763 }
764 }
765 if (extent_end == end && split == end) {
766 other_start = 0;
767 other_end = start;
768 if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino,
769 bytenr, &other_start, &other_end)) {
770 path->slots[0]--;
771 fi = btrfs_item_ptr(leaf, path->slots[0],
772 struct btrfs_file_extent_item);
773 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end -
774 other_start);
775 goto done;
776 }
777 }
778
779 btrfs_mark_buffer_dirty(leaf);
780
781 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
782 root->root_key.objectid,
783 inode->i_ino, orig_offset);
784 BUG_ON(ret);
785 btrfs_release_path(root, path);
786
787 key.offset = start;
788 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi));
789 BUG_ON(ret);
790
791 leaf = path->nodes[0];
792 fi = btrfs_item_ptr(leaf, path->slots[0],
793 struct btrfs_file_extent_item);
794 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
795 btrfs_set_file_extent_type(leaf, fi, extent_type);
796 btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr);
797 btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
798 btrfs_set_file_extent_offset(leaf, fi, key.offset - orig_offset);
799 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset);
800 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
801 btrfs_set_file_extent_compression(leaf, fi, 0);
802 btrfs_set_file_extent_encryption(leaf, fi, 0);
803 btrfs_set_file_extent_other_encoding(leaf, fi, 0);
804 done:
805 btrfs_mark_buffer_dirty(leaf);
806
807 release:
808 btrfs_release_path(root, path);
809 if (split_end && split == start) {
810 split = end;
811 goto again;
812 }
813 if (locked_end > end) {
814 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
815 GFP_NOFS);
816 }
817 btrfs_free_path(path);
818 return 0;
819 }
820
821 /*
822 * this gets pages into the page cache and locks them down, it also properly
823 * waits for data=ordered extents to finish before allowing the pages to be
824 * modified.
825 */
826 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
827 struct page **pages, size_t num_pages,
828 loff_t pos, unsigned long first_index,
829 unsigned long last_index, size_t write_bytes)
830 {
831 int i;
832 unsigned long index = pos >> PAGE_CACHE_SHIFT;
833 struct inode *inode = fdentry(file)->d_inode;
834 int err = 0;
835 u64 start_pos;
836 u64 last_pos;
837
838 start_pos = pos & ~((u64)root->sectorsize - 1);
839 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
840
841 if (start_pos > inode->i_size) {
842 err = btrfs_cont_expand(inode, start_pos);
843 if (err)
844 return err;
845 }
846
847 memset(pages, 0, num_pages * sizeof(struct page *));
848 again:
849 for (i = 0; i < num_pages; i++) {
850 pages[i] = grab_cache_page(inode->i_mapping, index + i);
851 if (!pages[i]) {
852 err = -ENOMEM;
853 BUG_ON(1);
854 }
855 wait_on_page_writeback(pages[i]);
856 }
857 if (start_pos < inode->i_size) {
858 struct btrfs_ordered_extent *ordered;
859 lock_extent(&BTRFS_I(inode)->io_tree,
860 start_pos, last_pos - 1, GFP_NOFS);
861 ordered = btrfs_lookup_first_ordered_extent(inode,
862 last_pos - 1);
863 if (ordered &&
864 ordered->file_offset + ordered->len > start_pos &&
865 ordered->file_offset < last_pos) {
866 btrfs_put_ordered_extent(ordered);
867 unlock_extent(&BTRFS_I(inode)->io_tree,
868 start_pos, last_pos - 1, GFP_NOFS);
869 for (i = 0; i < num_pages; i++) {
870 unlock_page(pages[i]);
871 page_cache_release(pages[i]);
872 }
873 btrfs_wait_ordered_range(inode, start_pos,
874 last_pos - start_pos);
875 goto again;
876 }
877 if (ordered)
878 btrfs_put_ordered_extent(ordered);
879
880 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
881 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
882 EXTENT_DO_ACCOUNTING,
883 GFP_NOFS);
884 unlock_extent(&BTRFS_I(inode)->io_tree,
885 start_pos, last_pos - 1, GFP_NOFS);
886 }
887 for (i = 0; i < num_pages; i++) {
888 clear_page_dirty_for_io(pages[i]);
889 set_page_extent_mapped(pages[i]);
890 WARN_ON(!PageLocked(pages[i]));
891 }
892 return 0;
893 }
894
895 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
896 size_t count, loff_t *ppos)
897 {
898 loff_t pos;
899 loff_t start_pos;
900 ssize_t num_written = 0;
901 ssize_t err = 0;
902 int ret = 0;
903 struct inode *inode = fdentry(file)->d_inode;
904 struct btrfs_root *root = BTRFS_I(inode)->root;
905 struct page **pages = NULL;
906 int nrptrs;
907 struct page *pinned[2];
908 unsigned long first_index;
909 unsigned long last_index;
910 int will_write;
911
912 will_write = ((file->f_flags & O_DSYNC) || IS_SYNC(inode) ||
913 (file->f_flags & O_DIRECT));
914
915 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
916 PAGE_CACHE_SIZE / (sizeof(struct page *)));
917 pinned[0] = NULL;
918 pinned[1] = NULL;
919
920 pos = *ppos;
921 start_pos = pos;
922
923 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
924
925 /* do the reserve before the mutex lock in case we have to do some
926 * flushing. We wouldn't deadlock, but this is more polite.
927 */
928 err = btrfs_reserve_metadata_for_delalloc(root, inode, 1);
929 if (err)
930 goto out_nolock;
931
932 mutex_lock(&inode->i_mutex);
933
934 current->backing_dev_info = inode->i_mapping->backing_dev_info;
935 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
936 if (err)
937 goto out;
938
939 if (count == 0)
940 goto out;
941
942 err = file_remove_suid(file);
943 if (err)
944 goto out;
945
946 file_update_time(file);
947
948 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
949
950 /* generic_write_checks can change our pos */
951 start_pos = pos;
952
953 BTRFS_I(inode)->sequence++;
954 first_index = pos >> PAGE_CACHE_SHIFT;
955 last_index = (pos + count) >> PAGE_CACHE_SHIFT;
956
957 /*
958 * there are lots of better ways to do this, but this code
959 * makes sure the first and last page in the file range are
960 * up to date and ready for cow
961 */
962 if ((pos & (PAGE_CACHE_SIZE - 1))) {
963 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
964 if (!PageUptodate(pinned[0])) {
965 ret = btrfs_readpage(NULL, pinned[0]);
966 BUG_ON(ret);
967 wait_on_page_locked(pinned[0]);
968 } else {
969 unlock_page(pinned[0]);
970 }
971 }
972 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
973 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
974 if (!PageUptodate(pinned[1])) {
975 ret = btrfs_readpage(NULL, pinned[1]);
976 BUG_ON(ret);
977 wait_on_page_locked(pinned[1]);
978 } else {
979 unlock_page(pinned[1]);
980 }
981 }
982
983 while (count > 0) {
984 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
985 size_t write_bytes = min(count, nrptrs *
986 (size_t)PAGE_CACHE_SIZE -
987 offset);
988 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
989 PAGE_CACHE_SHIFT;
990
991 WARN_ON(num_pages > nrptrs);
992 memset(pages, 0, sizeof(struct page *) * nrptrs);
993
994 ret = btrfs_check_data_free_space(root, inode, write_bytes);
995 if (ret)
996 goto out;
997
998 ret = prepare_pages(root, file, pages, num_pages,
999 pos, first_index, last_index,
1000 write_bytes);
1001 if (ret) {
1002 btrfs_free_reserved_data_space(root, inode,
1003 write_bytes);
1004 goto out;
1005 }
1006
1007 ret = btrfs_copy_from_user(pos, num_pages,
1008 write_bytes, pages, buf);
1009 if (ret) {
1010 btrfs_free_reserved_data_space(root, inode,
1011 write_bytes);
1012 btrfs_drop_pages(pages, num_pages);
1013 goto out;
1014 }
1015
1016 ret = dirty_and_release_pages(NULL, root, file, pages,
1017 num_pages, pos, write_bytes);
1018 btrfs_drop_pages(pages, num_pages);
1019 if (ret) {
1020 btrfs_free_reserved_data_space(root, inode,
1021 write_bytes);
1022 goto out;
1023 }
1024
1025 if (will_write) {
1026 filemap_fdatawrite_range(inode->i_mapping, pos,
1027 pos + write_bytes - 1);
1028 } else {
1029 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1030 num_pages);
1031 if (num_pages <
1032 (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1033 btrfs_btree_balance_dirty(root, 1);
1034 btrfs_throttle(root);
1035 }
1036
1037 buf += write_bytes;
1038 count -= write_bytes;
1039 pos += write_bytes;
1040 num_written += write_bytes;
1041
1042 cond_resched();
1043 }
1044 out:
1045 mutex_unlock(&inode->i_mutex);
1046 if (ret)
1047 err = ret;
1048 btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
1049
1050 out_nolock:
1051 kfree(pages);
1052 if (pinned[0])
1053 page_cache_release(pinned[0]);
1054 if (pinned[1])
1055 page_cache_release(pinned[1]);
1056 *ppos = pos;
1057
1058 /*
1059 * we want to make sure fsync finds this change
1060 * but we haven't joined a transaction running right now.
1061 *
1062 * Later on, someone is sure to update the inode and get the
1063 * real transid recorded.
1064 *
1065 * We set last_trans now to the fs_info generation + 1,
1066 * this will either be one more than the running transaction
1067 * or the generation used for the next transaction if there isn't
1068 * one running right now.
1069 */
1070 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1071
1072 if (num_written > 0 && will_write) {
1073 struct btrfs_trans_handle *trans;
1074
1075 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1076 if (err)
1077 num_written = err;
1078
1079 if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) {
1080 trans = btrfs_start_transaction(root, 1);
1081 ret = btrfs_log_dentry_safe(trans, root,
1082 file->f_dentry);
1083 if (ret == 0) {
1084 ret = btrfs_sync_log(trans, root);
1085 if (ret == 0)
1086 btrfs_end_transaction(trans, root);
1087 else
1088 btrfs_commit_transaction(trans, root);
1089 } else {
1090 btrfs_commit_transaction(trans, root);
1091 }
1092 }
1093 if (file->f_flags & O_DIRECT) {
1094 invalidate_mapping_pages(inode->i_mapping,
1095 start_pos >> PAGE_CACHE_SHIFT,
1096 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1097 }
1098 }
1099 current->backing_dev_info = NULL;
1100 return num_written ? num_written : err;
1101 }
1102
1103 int btrfs_release_file(struct inode *inode, struct file *filp)
1104 {
1105 /*
1106 * ordered_data_close is set by settattr when we are about to truncate
1107 * a file from a non-zero size to a zero size. This tries to
1108 * flush down new bytes that may have been written if the
1109 * application were using truncate to replace a file in place.
1110 */
1111 if (BTRFS_I(inode)->ordered_data_close) {
1112 BTRFS_I(inode)->ordered_data_close = 0;
1113 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1114 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1115 filemap_flush(inode->i_mapping);
1116 }
1117 if (filp->private_data)
1118 btrfs_ioctl_trans_end(filp);
1119 return 0;
1120 }
1121
1122 /*
1123 * fsync call for both files and directories. This logs the inode into
1124 * the tree log instead of forcing full commits whenever possible.
1125 *
1126 * It needs to call filemap_fdatawait so that all ordered extent updates are
1127 * in the metadata btree are up to date for copying to the log.
1128 *
1129 * It drops the inode mutex before doing the tree log commit. This is an
1130 * important optimization for directories because holding the mutex prevents
1131 * new operations on the dir while we write to disk.
1132 */
1133 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
1134 {
1135 struct inode *inode = dentry->d_inode;
1136 struct btrfs_root *root = BTRFS_I(inode)->root;
1137 int ret = 0;
1138 struct btrfs_trans_handle *trans;
1139
1140 /*
1141 * check the transaction that last modified this inode
1142 * and see if its already been committed
1143 */
1144 if (!BTRFS_I(inode)->last_trans)
1145 goto out;
1146
1147 mutex_lock(&root->fs_info->trans_mutex);
1148 if (BTRFS_I(inode)->last_trans <=
1149 root->fs_info->last_trans_committed) {
1150 BTRFS_I(inode)->last_trans = 0;
1151 mutex_unlock(&root->fs_info->trans_mutex);
1152 goto out;
1153 }
1154 mutex_unlock(&root->fs_info->trans_mutex);
1155
1156 root->log_batch++;
1157 filemap_fdatawrite(inode->i_mapping);
1158 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1159 root->log_batch++;
1160
1161 if (datasync && !(inode->i_state & I_DIRTY_PAGES))
1162 goto out;
1163 /*
1164 * ok we haven't committed the transaction yet, lets do a commit
1165 */
1166 if (file && file->private_data)
1167 btrfs_ioctl_trans_end(file);
1168
1169 trans = btrfs_start_transaction(root, 1);
1170 if (!trans) {
1171 ret = -ENOMEM;
1172 goto out;
1173 }
1174
1175 ret = btrfs_log_dentry_safe(trans, root, dentry);
1176 if (ret < 0)
1177 goto out;
1178
1179 /* we've logged all the items and now have a consistent
1180 * version of the file in the log. It is possible that
1181 * someone will come in and modify the file, but that's
1182 * fine because the log is consistent on disk, and we
1183 * have references to all of the file's extents
1184 *
1185 * It is possible that someone will come in and log the
1186 * file again, but that will end up using the synchronization
1187 * inside btrfs_sync_log to keep things safe.
1188 */
1189 mutex_unlock(&dentry->d_inode->i_mutex);
1190
1191 if (ret > 0) {
1192 ret = btrfs_commit_transaction(trans, root);
1193 } else {
1194 ret = btrfs_sync_log(trans, root);
1195 if (ret == 0)
1196 ret = btrfs_end_transaction(trans, root);
1197 else
1198 ret = btrfs_commit_transaction(trans, root);
1199 }
1200 mutex_lock(&dentry->d_inode->i_mutex);
1201 out:
1202 return ret > 0 ? EIO : ret;
1203 }
1204
1205 static const struct vm_operations_struct btrfs_file_vm_ops = {
1206 .fault = filemap_fault,
1207 .page_mkwrite = btrfs_page_mkwrite,
1208 };
1209
1210 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1211 {
1212 vma->vm_ops = &btrfs_file_vm_ops;
1213 file_accessed(filp);
1214 return 0;
1215 }
1216
1217 const struct file_operations btrfs_file_operations = {
1218 .llseek = generic_file_llseek,
1219 .read = do_sync_read,
1220 .aio_read = generic_file_aio_read,
1221 .splice_read = generic_file_splice_read,
1222 .write = btrfs_file_write,
1223 .mmap = btrfs_file_mmap,
1224 .open = generic_file_open,
1225 .release = btrfs_release_file,
1226 .fsync = btrfs_sync_file,
1227 .unlocked_ioctl = btrfs_ioctl,
1228 #ifdef CONFIG_COMPAT
1229 .compat_ioctl = btrfs_ioctl,
1230 #endif
1231 };
mm of the moment repository