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Merge commit 'origin/master' into next
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / btrfs / file.c
blob6ed434ac037faac00117e5d633478bd7a2e0805b
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 (testend && em->start + em->len >= start + len) {
183 free_extent_map(em);
184 write_unlock(&em_tree->lock);
185 break;
186 }
187 start = em->start + em->len;
188 if (testend)
189 len = start + len - (em->start + em->len);
190 free_extent_map(em);
191 write_unlock(&em_tree->lock);
192 continue;
193 }
194 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
195 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
196 remove_extent_mapping(em_tree, em);
197
198 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
199 em->start < start) {
200 split->start = em->start;
201 split->len = start - em->start;
202 split->orig_start = em->orig_start;
203 split->block_start = em->block_start;
204
205 if (compressed)
206 split->block_len = em->block_len;
207 else
208 split->block_len = split->len;
209
210 split->bdev = em->bdev;
211 split->flags = flags;
212 ret = add_extent_mapping(em_tree, split);
213 BUG_ON(ret);
214 free_extent_map(split);
215 split = split2;
216 split2 = NULL;
217 }
218 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
219 testend && em->start + em->len > start + len) {
220 u64 diff = start + len - em->start;
221
222 split->start = start + len;
223 split->len = em->start + em->len - (start + len);
224 split->bdev = em->bdev;
225 split->flags = flags;
226
227 if (compressed) {
228 split->block_len = em->block_len;
229 split->block_start = em->block_start;
230 split->orig_start = em->orig_start;
231 } else {
232 split->block_len = split->len;
233 split->block_start = em->block_start + diff;
234 split->orig_start = split->start;
235 }
236
237 ret = add_extent_mapping(em_tree, split);
238 BUG_ON(ret);
239 free_extent_map(split);
240 split = NULL;
241 }
242 write_unlock(&em_tree->lock);
243
244 /* once for us */
245 free_extent_map(em);
246 /* once for the tree*/
247 free_extent_map(em);
248 }
249 if (split)
250 free_extent_map(split);
251 if (split2)
252 free_extent_map(split2);
253 return 0;
254 }
255
256 /*
257 * this is very complex, but the basic idea is to drop all extents
258 * in the range start - end. hint_block is filled in with a block number
259 * that would be a good hint to the block allocator for this file.
260 *
261 * If an extent intersects the range but is not entirely inside the range
262 * it is either truncated or split. Anything entirely inside the range
263 * is deleted from the tree.
264 */
265 int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
266 u64 start, u64 end, u64 *hint_byte, int drop_cache)
267 {
268 struct btrfs_root *root = BTRFS_I(inode)->root;
269 struct extent_buffer *leaf;
270 struct btrfs_file_extent_item *fi;
271 struct btrfs_path *path;
272 struct btrfs_key key;
273 struct btrfs_key new_key;
274 u64 search_start = start;
275 u64 disk_bytenr = 0;
276 u64 num_bytes = 0;
277 u64 extent_offset = 0;
278 u64 extent_end = 0;
279 int del_nr = 0;
280 int del_slot = 0;
281 int extent_type;
282 int recow;
283 int ret;
284
285 if (drop_cache)
286 btrfs_drop_extent_cache(inode, start, end - 1, 0);
287
288 path = btrfs_alloc_path();
289 if (!path)
290 return -ENOMEM;
291
292 while (1) {
293 recow = 0;
294 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
295 search_start, -1);
296 if (ret < 0)
297 break;
298 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
299 leaf = path->nodes[0];
300 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
301 if (key.objectid == inode->i_ino &&
302 key.type == BTRFS_EXTENT_DATA_KEY)
303 path->slots[0]--;
304 }
305 ret = 0;
306 next_slot:
307 leaf = path->nodes[0];
308 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
309 BUG_ON(del_nr > 0);
310 ret = btrfs_next_leaf(root, path);
311 if (ret < 0)
312 break;
313 if (ret > 0) {
314 ret = 0;
315 break;
316 }
317 leaf = path->nodes[0];
318 recow = 1;
319 }
320
321 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
322 if (key.objectid > inode->i_ino ||
323 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
324 break;
325
326 fi = btrfs_item_ptr(leaf, path->slots[0],
327 struct btrfs_file_extent_item);
328 extent_type = btrfs_file_extent_type(leaf, fi);
329
330 if (extent_type == BTRFS_FILE_EXTENT_REG ||
331 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
332 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
333 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
334 extent_offset = btrfs_file_extent_offset(leaf, fi);
335 extent_end = key.offset +
336 btrfs_file_extent_num_bytes(leaf, fi);
337 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
338 extent_end = key.offset +
339 btrfs_file_extent_inline_len(leaf, fi);
340 } else {
341 WARN_ON(1);
342 extent_end = search_start;
343 }
344
345 if (extent_end <= search_start) {
346 path->slots[0]++;
347 goto next_slot;
348 }
349
350 search_start = max(key.offset, start);
351 if (recow) {
352 btrfs_release_path(root, path);
353 continue;
354 }
355
356 /*
357 * | - range to drop - |
358 * | -------- extent -------- |
359 */
360 if (start > key.offset && end < extent_end) {
361 BUG_ON(del_nr > 0);
362 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
363
364 memcpy(&new_key, &key, sizeof(new_key));
365 new_key.offset = start;
366 ret = btrfs_duplicate_item(trans, root, path,
367 &new_key);
368 if (ret == -EAGAIN) {
369 btrfs_release_path(root, path);
370 continue;
371 }
372 if (ret < 0)
373 break;
374
375 leaf = path->nodes[0];
376 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
377 struct btrfs_file_extent_item);
378 btrfs_set_file_extent_num_bytes(leaf, fi,
379 start - key.offset);
380
381 fi = btrfs_item_ptr(leaf, path->slots[0],
382 struct btrfs_file_extent_item);
383
384 extent_offset += start - key.offset;
385 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
386 btrfs_set_file_extent_num_bytes(leaf, fi,
387 extent_end - start);
388 btrfs_mark_buffer_dirty(leaf);
389
390 if (disk_bytenr > 0) {
391 ret = btrfs_inc_extent_ref(trans, root,
392 disk_bytenr, num_bytes, 0,
393 root->root_key.objectid,
394 new_key.objectid,
395 start - extent_offset);
396 BUG_ON(ret);
397 *hint_byte = disk_bytenr;
398 }
399 key.offset = start;
400 }
401 /*
402 * | ---- range to drop ----- |
403 * | -------- extent -------- |
404 */
405 if (start <= key.offset && end < extent_end) {
406 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
407
408 memcpy(&new_key, &key, sizeof(new_key));
409 new_key.offset = end;
410 btrfs_set_item_key_safe(trans, root, path, &new_key);
411
412 extent_offset += end - key.offset;
413 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
414 btrfs_set_file_extent_num_bytes(leaf, fi,
415 extent_end - end);
416 btrfs_mark_buffer_dirty(leaf);
417 if (disk_bytenr > 0) {
418 inode_sub_bytes(inode, end - key.offset);
419 *hint_byte = disk_bytenr;
420 }
421 break;
422 }
423
424 search_start = extent_end;
425 /*
426 * | ---- range to drop ----- |
427 * | -------- extent -------- |
428 */
429 if (start > key.offset && end >= extent_end) {
430 BUG_ON(del_nr > 0);
431 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
432
433 btrfs_set_file_extent_num_bytes(leaf, fi,
434 start - key.offset);
435 btrfs_mark_buffer_dirty(leaf);
436 if (disk_bytenr > 0) {
437 inode_sub_bytes(inode, extent_end - start);
438 *hint_byte = disk_bytenr;
439 }
440 if (end == extent_end)
441 break;
442
443 path->slots[0]++;
444 goto next_slot;
445 }
446
447 /*
448 * | ---- range to drop ----- |
449 * | ------ extent ------ |
450 */
451 if (start <= key.offset && end >= extent_end) {
452 if (del_nr == 0) {
453 del_slot = path->slots[0];
454 del_nr = 1;
455 } else {
456 BUG_ON(del_slot + del_nr != path->slots[0]);
457 del_nr++;
458 }
459
460 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
461 inode_sub_bytes(inode,
462 extent_end - key.offset);
463 extent_end = ALIGN(extent_end,
464 root->sectorsize);
465 } else if (disk_bytenr > 0) {
466 ret = btrfs_free_extent(trans, root,
467 disk_bytenr, num_bytes, 0,
468 root->root_key.objectid,
469 key.objectid, key.offset -
470 extent_offset);
471 BUG_ON(ret);
472 inode_sub_bytes(inode,
473 extent_end - key.offset);
474 *hint_byte = disk_bytenr;
475 }
476
477 if (end == extent_end)
478 break;
479
480 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
481 path->slots[0]++;
482 goto next_slot;
483 }
484
485 ret = btrfs_del_items(trans, root, path, del_slot,
486 del_nr);
487 BUG_ON(ret);
488
489 del_nr = 0;
490 del_slot = 0;
491
492 btrfs_release_path(root, path);
493 continue;
494 }
495
496 BUG_ON(1);
497 }
498
499 if (del_nr > 0) {
500 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
501 BUG_ON(ret);
502 }
503
504 btrfs_free_path(path);
505 return ret;
506 }
507
508 static int extent_mergeable(struct extent_buffer *leaf, int slot,
509 u64 objectid, u64 bytenr, u64 orig_offset,
510 u64 *start, u64 *end)
511 {
512 struct btrfs_file_extent_item *fi;
513 struct btrfs_key key;
514 u64 extent_end;
515
516 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
517 return 0;
518
519 btrfs_item_key_to_cpu(leaf, &key, slot);
520 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
521 return 0;
522
523 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
524 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
525 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
526 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
527 btrfs_file_extent_compression(leaf, fi) ||
528 btrfs_file_extent_encryption(leaf, fi) ||
529 btrfs_file_extent_other_encoding(leaf, fi))
530 return 0;
531
532 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
533 if ((*start && *start != key.offset) || (*end && *end != extent_end))
534 return 0;
535
536 *start = key.offset;
537 *end = extent_end;
538 return 1;
539 }
540
541 /*
542 * Mark extent in the range start - end as written.
543 *
544 * This changes extent type from 'pre-allocated' to 'regular'. If only
545 * part of extent is marked as written, the extent will be split into
546 * two or three.
547 */
548 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
549 struct inode *inode, u64 start, u64 end)
550 {
551 struct btrfs_root *root = BTRFS_I(inode)->root;
552 struct extent_buffer *leaf;
553 struct btrfs_path *path;
554 struct btrfs_file_extent_item *fi;
555 struct btrfs_key key;
556 struct btrfs_key new_key;
557 u64 bytenr;
558 u64 num_bytes;
559 u64 extent_end;
560 u64 orig_offset;
561 u64 other_start;
562 u64 other_end;
563 u64 split;
564 int del_nr = 0;
565 int del_slot = 0;
566 int recow;
567 int ret;
568
569 btrfs_drop_extent_cache(inode, start, end - 1, 0);
570
571 path = btrfs_alloc_path();
572 BUG_ON(!path);
573 again:
574 recow = 0;
575 split = start;
576 key.objectid = inode->i_ino;
577 key.type = BTRFS_EXTENT_DATA_KEY;
578 key.offset = split;
579
580 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
581 if (ret > 0 && path->slots[0] > 0)
582 path->slots[0]--;
583
584 leaf = path->nodes[0];
585 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
586 BUG_ON(key.objectid != inode->i_ino ||
587 key.type != BTRFS_EXTENT_DATA_KEY);
588 fi = btrfs_item_ptr(leaf, path->slots[0],
589 struct btrfs_file_extent_item);
590 BUG_ON(btrfs_file_extent_type(leaf, fi) !=
591 BTRFS_FILE_EXTENT_PREALLOC);
592 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
593 BUG_ON(key.offset > start || extent_end < end);
594
595 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
596 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
597 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
598 memcpy(&new_key, &key, sizeof(new_key));
599
600 if (start == key.offset && end < extent_end) {
601 other_start = 0;
602 other_end = start;
603 if (extent_mergeable(leaf, path->slots[0] - 1,
604 inode->i_ino, bytenr, orig_offset,
605 &other_start, &other_end)) {
606 new_key.offset = end;
607 btrfs_set_item_key_safe(trans, root, path, &new_key);
608 fi = btrfs_item_ptr(leaf, path->slots[0],
609 struct btrfs_file_extent_item);
610 btrfs_set_file_extent_num_bytes(leaf, fi,
611 extent_end - end);
612 btrfs_set_file_extent_offset(leaf, fi,
613 end - orig_offset);
614 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
615 struct btrfs_file_extent_item);
616 btrfs_set_file_extent_num_bytes(leaf, fi,
617 end - other_start);
618 btrfs_mark_buffer_dirty(leaf);
619 goto out;
620 }
621 }
622
623 if (start > key.offset && end == extent_end) {
624 other_start = end;
625 other_end = 0;
626 if (extent_mergeable(leaf, path->slots[0] + 1,
627 inode->i_ino, bytenr, orig_offset,
628 &other_start, &other_end)) {
629 fi = btrfs_item_ptr(leaf, path->slots[0],
630 struct btrfs_file_extent_item);
631 btrfs_set_file_extent_num_bytes(leaf, fi,
632 start - key.offset);
633 path->slots[0]++;
634 new_key.offset = start;
635 btrfs_set_item_key_safe(trans, root, path, &new_key);
636
637 fi = btrfs_item_ptr(leaf, path->slots[0],
638 struct btrfs_file_extent_item);
639 btrfs_set_file_extent_num_bytes(leaf, fi,
640 other_end - start);
641 btrfs_set_file_extent_offset(leaf, fi,
642 start - orig_offset);
643 btrfs_mark_buffer_dirty(leaf);
644 goto out;
645 }
646 }
647
648 while (start > key.offset || end < extent_end) {
649 if (key.offset == start)
650 split = end;
651
652 new_key.offset = split;
653 ret = btrfs_duplicate_item(trans, root, path, &new_key);
654 if (ret == -EAGAIN) {
655 btrfs_release_path(root, path);
656 goto again;
657 }
658 BUG_ON(ret < 0);
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 split - key.offset);
665
666 fi = btrfs_item_ptr(leaf, path->slots[0],
667 struct btrfs_file_extent_item);
668
669 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
670 btrfs_set_file_extent_num_bytes(leaf, fi,
671 extent_end - split);
672 btrfs_mark_buffer_dirty(leaf);
673
674 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
675 root->root_key.objectid,
676 inode->i_ino, orig_offset);
677 BUG_ON(ret);
678
679 if (split == start) {
680 key.offset = start;
681 } else {
682 BUG_ON(start != key.offset);
683 path->slots[0]--;
684 extent_end = end;
685 }
686 recow = 1;
687 }
688
689 other_start = end;
690 other_end = 0;
691 if (extent_mergeable(leaf, path->slots[0] + 1,
692 inode->i_ino, bytenr, orig_offset,
693 &other_start, &other_end)) {
694 if (recow) {
695 btrfs_release_path(root, path);
696 goto again;
697 }
698 extent_end = other_end;
699 del_slot = path->slots[0] + 1;
700 del_nr++;
701 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
702 0, root->root_key.objectid,
703 inode->i_ino, orig_offset);
704 BUG_ON(ret);
705 }
706 other_start = 0;
707 other_end = start;
708 if (extent_mergeable(leaf, path->slots[0] - 1,
709 inode->i_ino, bytenr, orig_offset,
710 &other_start, &other_end)) {
711 if (recow) {
712 btrfs_release_path(root, path);
713 goto again;
714 }
715 key.offset = other_start;
716 del_slot = path->slots[0];
717 del_nr++;
718 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
719 0, root->root_key.objectid,
720 inode->i_ino, orig_offset);
721 BUG_ON(ret);
722 }
723 if (del_nr == 0) {
724 fi = btrfs_item_ptr(leaf, path->slots[0],
725 struct btrfs_file_extent_item);
726 btrfs_set_file_extent_type(leaf, fi,
727 BTRFS_FILE_EXTENT_REG);
728 btrfs_mark_buffer_dirty(leaf);
729 } else {
730 fi = btrfs_item_ptr(leaf, del_slot - 1,
731 struct btrfs_file_extent_item);
732 btrfs_set_file_extent_type(leaf, fi,
733 BTRFS_FILE_EXTENT_REG);
734 btrfs_set_file_extent_num_bytes(leaf, fi,
735 extent_end - key.offset);
736 btrfs_mark_buffer_dirty(leaf);
737
738 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
739 BUG_ON(ret);
740 }
741 out:
742 btrfs_free_path(path);
743 return 0;
744 }
745
746 /*
747 * this gets pages into the page cache and locks them down, it also properly
748 * waits for data=ordered extents to finish before allowing the pages to be
749 * modified.
750 */
751 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
752 struct page **pages, size_t num_pages,
753 loff_t pos, unsigned long first_index,
754 unsigned long last_index, size_t write_bytes)
755 {
756 int i;
757 unsigned long index = pos >> PAGE_CACHE_SHIFT;
758 struct inode *inode = fdentry(file)->d_inode;
759 int err = 0;
760 u64 start_pos;
761 u64 last_pos;
762
763 start_pos = pos & ~((u64)root->sectorsize - 1);
764 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
765
766 if (start_pos > inode->i_size) {
767 err = btrfs_cont_expand(inode, start_pos);
768 if (err)
769 return err;
770 }
771
772 memset(pages, 0, num_pages * sizeof(struct page *));
773 again:
774 for (i = 0; i < num_pages; i++) {
775 pages[i] = grab_cache_page(inode->i_mapping, index + i);
776 if (!pages[i]) {
777 err = -ENOMEM;
778 BUG_ON(1);
779 }
780 wait_on_page_writeback(pages[i]);
781 }
782 if (start_pos < inode->i_size) {
783 struct btrfs_ordered_extent *ordered;
784 lock_extent(&BTRFS_I(inode)->io_tree,
785 start_pos, last_pos - 1, GFP_NOFS);
786 ordered = btrfs_lookup_first_ordered_extent(inode,
787 last_pos - 1);
788 if (ordered &&
789 ordered->file_offset + ordered->len > start_pos &&
790 ordered->file_offset < last_pos) {
791 btrfs_put_ordered_extent(ordered);
792 unlock_extent(&BTRFS_I(inode)->io_tree,
793 start_pos, last_pos - 1, GFP_NOFS);
794 for (i = 0; i < num_pages; i++) {
795 unlock_page(pages[i]);
796 page_cache_release(pages[i]);
797 }
798 btrfs_wait_ordered_range(inode, start_pos,
799 last_pos - start_pos);
800 goto again;
801 }
802 if (ordered)
803 btrfs_put_ordered_extent(ordered);
804
805 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
806 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
807 EXTENT_DO_ACCOUNTING,
808 GFP_NOFS);
809 unlock_extent(&BTRFS_I(inode)->io_tree,
810 start_pos, last_pos - 1, GFP_NOFS);
811 }
812 for (i = 0; i < num_pages; i++) {
813 clear_page_dirty_for_io(pages[i]);
814 set_page_extent_mapped(pages[i]);
815 WARN_ON(!PageLocked(pages[i]));
816 }
817 return 0;
818 }
819
820 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
821 size_t count, loff_t *ppos)
822 {
823 loff_t pos;
824 loff_t start_pos;
825 ssize_t num_written = 0;
826 ssize_t err = 0;
827 int ret = 0;
828 struct inode *inode = fdentry(file)->d_inode;
829 struct btrfs_root *root = BTRFS_I(inode)->root;
830 struct page **pages = NULL;
831 int nrptrs;
832 struct page *pinned[2];
833 unsigned long first_index;
834 unsigned long last_index;
835 int will_write;
836
837 will_write = ((file->f_flags & O_DSYNC) || IS_SYNC(inode) ||
838 (file->f_flags & O_DIRECT));
839
840 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
841 PAGE_CACHE_SIZE / (sizeof(struct page *)));
842 pinned[0] = NULL;
843 pinned[1] = NULL;
844
845 pos = *ppos;
846 start_pos = pos;
847
848 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
849
850 /* do the reserve before the mutex lock in case we have to do some
851 * flushing. We wouldn't deadlock, but this is more polite.
852 */
853 err = btrfs_reserve_metadata_for_delalloc(root, inode, 1);
854 if (err)
855 goto out_nolock;
856
857 mutex_lock(&inode->i_mutex);
858
859 current->backing_dev_info = inode->i_mapping->backing_dev_info;
860 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
861 if (err)
862 goto out;
863
864 if (count == 0)
865 goto out;
866
867 err = file_remove_suid(file);
868 if (err)
869 goto out;
870
871 file_update_time(file);
872
873 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
874
875 /* generic_write_checks can change our pos */
876 start_pos = pos;
877
878 BTRFS_I(inode)->sequence++;
879 first_index = pos >> PAGE_CACHE_SHIFT;
880 last_index = (pos + count) >> PAGE_CACHE_SHIFT;
881
882 /*
883 * there are lots of better ways to do this, but this code
884 * makes sure the first and last page in the file range are
885 * up to date and ready for cow
886 */
887 if ((pos & (PAGE_CACHE_SIZE - 1))) {
888 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
889 if (!PageUptodate(pinned[0])) {
890 ret = btrfs_readpage(NULL, pinned[0]);
891 BUG_ON(ret);
892 wait_on_page_locked(pinned[0]);
893 } else {
894 unlock_page(pinned[0]);
895 }
896 }
897 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
898 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
899 if (!PageUptodate(pinned[1])) {
900 ret = btrfs_readpage(NULL, pinned[1]);
901 BUG_ON(ret);
902 wait_on_page_locked(pinned[1]);
903 } else {
904 unlock_page(pinned[1]);
905 }
906 }
907
908 while (count > 0) {
909 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
910 size_t write_bytes = min(count, nrptrs *
911 (size_t)PAGE_CACHE_SIZE -
912 offset);
913 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
914 PAGE_CACHE_SHIFT;
915
916 WARN_ON(num_pages > nrptrs);
917 memset(pages, 0, sizeof(struct page *) * nrptrs);
918
919 ret = btrfs_check_data_free_space(root, inode, write_bytes);
920 if (ret)
921 goto out;
922
923 ret = prepare_pages(root, file, pages, num_pages,
924 pos, first_index, last_index,
925 write_bytes);
926 if (ret) {
927 btrfs_free_reserved_data_space(root, inode,
928 write_bytes);
929 goto out;
930 }
931
932 ret = btrfs_copy_from_user(pos, num_pages,
933 write_bytes, pages, buf);
934 if (ret) {
935 btrfs_free_reserved_data_space(root, inode,
936 write_bytes);
937 btrfs_drop_pages(pages, num_pages);
938 goto out;
939 }
940
941 ret = dirty_and_release_pages(NULL, root, file, pages,
942 num_pages, pos, write_bytes);
943 btrfs_drop_pages(pages, num_pages);
944 if (ret) {
945 btrfs_free_reserved_data_space(root, inode,
946 write_bytes);
947 goto out;
948 }
949
950 if (will_write) {
951 filemap_fdatawrite_range(inode->i_mapping, pos,
952 pos + write_bytes - 1);
953 } else {
954 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
955 num_pages);
956 if (num_pages <
957 (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
958 btrfs_btree_balance_dirty(root, 1);
959 btrfs_throttle(root);
960 }
961
962 buf += write_bytes;
963 count -= write_bytes;
964 pos += write_bytes;
965 num_written += write_bytes;
966
967 cond_resched();
968 }
969 out:
970 mutex_unlock(&inode->i_mutex);
971 if (ret)
972 err = ret;
973 btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
974
975 out_nolock:
976 kfree(pages);
977 if (pinned[0])
978 page_cache_release(pinned[0]);
979 if (pinned[1])
980 page_cache_release(pinned[1]);
981 *ppos = pos;
982
983 /*
984 * we want to make sure fsync finds this change
985 * but we haven't joined a transaction running right now.
986 *
987 * Later on, someone is sure to update the inode and get the
988 * real transid recorded.
989 *
990 * We set last_trans now to the fs_info generation + 1,
991 * this will either be one more than the running transaction
992 * or the generation used for the next transaction if there isn't
993 * one running right now.
994 */
995 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
996
997 if (num_written > 0 && will_write) {
998 struct btrfs_trans_handle *trans;
999
1000 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1001 if (err)
1002 num_written = err;
1003
1004 if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) {
1005 trans = btrfs_start_transaction(root, 1);
1006 ret = btrfs_log_dentry_safe(trans, root,
1007 file->f_dentry);
1008 if (ret == 0) {
1009 ret = btrfs_sync_log(trans, root);
1010 if (ret == 0)
1011 btrfs_end_transaction(trans, root);
1012 else
1013 btrfs_commit_transaction(trans, root);
1014 } else if (ret != BTRFS_NO_LOG_SYNC) {
1015 btrfs_commit_transaction(trans, root);
1016 } else {
1017 btrfs_end_transaction(trans, root);
1018 }
1019 }
1020 if (file->f_flags & O_DIRECT) {
1021 invalidate_mapping_pages(inode->i_mapping,
1022 start_pos >> PAGE_CACHE_SHIFT,
1023 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1024 }
1025 }
1026 current->backing_dev_info = NULL;
1027 return num_written ? num_written : err;
1028 }
1029
1030 int btrfs_release_file(struct inode *inode, struct file *filp)
1031 {
1032 /*
1033 * ordered_data_close is set by settattr when we are about to truncate
1034 * a file from a non-zero size to a zero size. This tries to
1035 * flush down new bytes that may have been written if the
1036 * application were using truncate to replace a file in place.
1037 */
1038 if (BTRFS_I(inode)->ordered_data_close) {
1039 BTRFS_I(inode)->ordered_data_close = 0;
1040 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1041 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1042 filemap_flush(inode->i_mapping);
1043 }
1044 if (filp->private_data)
1045 btrfs_ioctl_trans_end(filp);
1046 return 0;
1047 }
1048
1049 /*
1050 * fsync call for both files and directories. This logs the inode into
1051 * the tree log instead of forcing full commits whenever possible.
1052 *
1053 * It needs to call filemap_fdatawait so that all ordered extent updates are
1054 * in the metadata btree are up to date for copying to the log.
1055 *
1056 * It drops the inode mutex before doing the tree log commit. This is an
1057 * important optimization for directories because holding the mutex prevents
1058 * new operations on the dir while we write to disk.
1059 */
1060 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
1061 {
1062 struct inode *inode = dentry->d_inode;
1063 struct btrfs_root *root = BTRFS_I(inode)->root;
1064 int ret = 0;
1065 struct btrfs_trans_handle *trans;
1066
1067
1068 /* we wait first, since the writeback may change the inode */
1069 root->log_batch++;
1070 /* the VFS called filemap_fdatawrite for us */
1071 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1072 root->log_batch++;
1073
1074 /*
1075 * check the transaction that last modified this inode
1076 * and see if its already been committed
1077 */
1078 if (!BTRFS_I(inode)->last_trans)
1079 goto out;
1080
1081 /*
1082 * if the last transaction that changed this file was before
1083 * the current transaction, we can bail out now without any
1084 * syncing
1085 */
1086 mutex_lock(&root->fs_info->trans_mutex);
1087 if (BTRFS_I(inode)->last_trans <=
1088 root->fs_info->last_trans_committed) {
1089 BTRFS_I(inode)->last_trans = 0;
1090 mutex_unlock(&root->fs_info->trans_mutex);
1091 goto out;
1092 }
1093 mutex_unlock(&root->fs_info->trans_mutex);
1094
1095 /*
1096 * ok we haven't committed the transaction yet, lets do a commit
1097 */
1098 if (file && file->private_data)
1099 btrfs_ioctl_trans_end(file);
1100
1101 trans = btrfs_start_transaction(root, 1);
1102 if (!trans) {
1103 ret = -ENOMEM;
1104 goto out;
1105 }
1106
1107 ret = btrfs_log_dentry_safe(trans, root, dentry);
1108 if (ret < 0)
1109 goto out;
1110
1111 /* we've logged all the items and now have a consistent
1112 * version of the file in the log. It is possible that
1113 * someone will come in and modify the file, but that's
1114 * fine because the log is consistent on disk, and we
1115 * have references to all of the file's extents
1116 *
1117 * It is possible that someone will come in and log the
1118 * file again, but that will end up using the synchronization
1119 * inside btrfs_sync_log to keep things safe.
1120 */
1121 mutex_unlock(&dentry->d_inode->i_mutex);
1122
1123 if (ret != BTRFS_NO_LOG_SYNC) {
1124 if (ret > 0) {
1125 ret = btrfs_commit_transaction(trans, root);
1126 } else {
1127 ret = btrfs_sync_log(trans, root);
1128 if (ret == 0)
1129 ret = btrfs_end_transaction(trans, root);
1130 else
1131 ret = btrfs_commit_transaction(trans, root);
1132 }
1133 } else {
1134 ret = btrfs_end_transaction(trans, root);
1135 }
1136 mutex_lock(&dentry->d_inode->i_mutex);
1137 out:
1138 return ret > 0 ? -EIO : ret;
1139 }
1140
1141 static const struct vm_operations_struct btrfs_file_vm_ops = {
1142 .fault = filemap_fault,
1143 .page_mkwrite = btrfs_page_mkwrite,
1144 };
1145
1146 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1147 {
1148 vma->vm_ops = &btrfs_file_vm_ops;
1149 file_accessed(filp);
1150 return 0;
1151 }
1152
1153 const struct file_operations btrfs_file_operations = {
1154 .llseek = generic_file_llseek,
1155 .read = do_sync_read,
1156 .aio_read = generic_file_aio_read,
1157 .splice_read = generic_file_splice_read,
1158 .write = btrfs_file_write,
1159 .mmap = btrfs_file_mmap,
1160 .open = generic_file_open,
1161 .release = btrfs_release_file,
1162 .fsync = btrfs_sync_file,
1163 .unlocked_ioctl = btrfs_ioctl,
1164 #ifdef CONFIG_COMPAT
1165 .compat_ioctl = btrfs_ioctl,
1166 #endif
1167 };
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree