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Staging: pata_rdc: convert code to work in 2.6.29
[linux-2.6.git] / fs / btrfs / file.c
blob126477eaecf56f074a03581c17079d6b985caa81
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/smp_lock.h>
26 #include <linux/backing-dev.h>
27 #include <linux/mpage.h>
28 #include <linux/swap.h>
29 #include <linux/writeback.h>
30 #include <linux/statfs.h>
31 #include <linux/compat.h>
32 #include "ctree.h"
33 #include "disk-io.h"
34 #include "transaction.h"
35 #include "btrfs_inode.h"
36 #include "ioctl.h"
37 #include "print-tree.h"
38 #include "tree-log.h"
39 #include "locking.h"
40 #include "compat.h"
41
42
43 /* simple helper to fault in pages and copy. This should go away
44 * and be replaced with calls into generic code.
45 */
46 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
47 int write_bytes,
48 struct page **prepared_pages,
49 const char __user *buf)
50 {
51 long page_fault = 0;
52 int i;
53 int offset = pos & (PAGE_CACHE_SIZE - 1);
54
55 for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
56 size_t count = min_t(size_t,
57 PAGE_CACHE_SIZE - offset, write_bytes);
58 struct page *page = prepared_pages[i];
59 fault_in_pages_readable(buf, count);
60
61 /* Copy data from userspace to the current page */
62 kmap(page);
63 page_fault = __copy_from_user(page_address(page) + offset,
64 buf, count);
65 /* Flush processor's dcache for this page */
66 flush_dcache_page(page);
67 kunmap(page);
68 buf += count;
69 write_bytes -= count;
70
71 if (page_fault)
72 break;
73 }
74 return page_fault ? -EFAULT : 0;
75 }
76
77 /*
78 * unlocks pages after btrfs_file_write is done with them
79 */
80 static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages)
81 {
82 size_t i;
83 for (i = 0; i < num_pages; i++) {
84 if (!pages[i])
85 break;
86 /* page checked is some magic around finding pages that
87 * have been modified without going through btrfs_set_page_dirty
88 * clear it here
89 */
90 ClearPageChecked(pages[i]);
91 unlock_page(pages[i]);
92 mark_page_accessed(pages[i]);
93 page_cache_release(pages[i]);
94 }
95 }
96
97 /*
98 * after copy_from_user, pages need to be dirtied and we need to make
99 * sure holes are created between the current EOF and the start of
100 * any next extents (if required).
101 *
102 * this also makes the decision about creating an inline extent vs
103 * doing real data extents, marking pages dirty and delalloc as required.
104 */
105 static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
106 struct btrfs_root *root,
107 struct file *file,
108 struct page **pages,
109 size_t num_pages,
110 loff_t pos,
111 size_t write_bytes)
112 {
113 int err = 0;
114 int i;
115 struct inode *inode = fdentry(file)->d_inode;
116 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
117 u64 hint_byte;
118 u64 num_bytes;
119 u64 start_pos;
120 u64 end_of_last_block;
121 u64 end_pos = pos + write_bytes;
122 loff_t isize = i_size_read(inode);
123
124 start_pos = pos & ~((u64)root->sectorsize - 1);
125 num_bytes = (write_bytes + pos - start_pos +
126 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
127
128 end_of_last_block = start_pos + num_bytes - 1;
129
130 lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
131 trans = btrfs_join_transaction(root, 1);
132 if (!trans) {
133 err = -ENOMEM;
134 goto out_unlock;
135 }
136 btrfs_set_trans_block_group(trans, inode);
137 hint_byte = 0;
138
139 set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
140
141 /* check for reserved extents on each page, we don't want
142 * to reset the delalloc bit on things that already have
143 * extents reserved.
144 */
145 btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
146 for (i = 0; i < num_pages; i++) {
147 struct page *p = pages[i];
148 SetPageUptodate(p);
149 ClearPageChecked(p);
150 set_page_dirty(p);
151 }
152 if (end_pos > isize) {
153 i_size_write(inode, end_pos);
154 btrfs_update_inode(trans, root, inode);
155 }
156 err = btrfs_end_transaction(trans, root);
157 out_unlock:
158 unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
159 return err;
160 }
161
162 /*
163 * this drops all the extents in the cache that intersect the range
164 * [start, end]. Existing extents are split as required.
165 */
166 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
167 int skip_pinned)
168 {
169 struct extent_map *em;
170 struct extent_map *split = NULL;
171 struct extent_map *split2 = NULL;
172 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
173 u64 len = end - start + 1;
174 int ret;
175 int testend = 1;
176 unsigned long flags;
177 int compressed = 0;
178
179 WARN_ON(end < start);
180 if (end == (u64)-1) {
181 len = (u64)-1;
182 testend = 0;
183 }
184 while (1) {
185 if (!split)
186 split = alloc_extent_map(GFP_NOFS);
187 if (!split2)
188 split2 = alloc_extent_map(GFP_NOFS);
189
190 spin_lock(&em_tree->lock);
191 em = lookup_extent_mapping(em_tree, start, len);
192 if (!em) {
193 spin_unlock(&em_tree->lock);
194 break;
195 }
196 flags = em->flags;
197 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
198 spin_unlock(&em_tree->lock);
199 if (em->start <= start &&
200 (!testend || em->start + em->len >= start + len)) {
201 free_extent_map(em);
202 break;
203 }
204 if (start < em->start) {
205 len = em->start - start;
206 } else {
207 len = start + len - (em->start + em->len);
208 start = em->start + em->len;
209 }
210 free_extent_map(em);
211 continue;
212 }
213 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
214 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
215 remove_extent_mapping(em_tree, em);
216
217 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
218 em->start < start) {
219 split->start = em->start;
220 split->len = start - em->start;
221 split->orig_start = em->orig_start;
222 split->block_start = em->block_start;
223
224 if (compressed)
225 split->block_len = em->block_len;
226 else
227 split->block_len = split->len;
228
229 split->bdev = em->bdev;
230 split->flags = flags;
231 ret = add_extent_mapping(em_tree, split);
232 BUG_ON(ret);
233 free_extent_map(split);
234 split = split2;
235 split2 = NULL;
236 }
237 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
238 testend && em->start + em->len > start + len) {
239 u64 diff = start + len - em->start;
240
241 split->start = start + len;
242 split->len = em->start + em->len - (start + len);
243 split->bdev = em->bdev;
244 split->flags = flags;
245
246 if (compressed) {
247 split->block_len = em->block_len;
248 split->block_start = em->block_start;
249 split->orig_start = em->orig_start;
250 } else {
251 split->block_len = split->len;
252 split->block_start = em->block_start + diff;
253 split->orig_start = split->start;
254 }
255
256 ret = add_extent_mapping(em_tree, split);
257 BUG_ON(ret);
258 free_extent_map(split);
259 split = NULL;
260 }
261 spin_unlock(&em_tree->lock);
262
263 /* once for us */
264 free_extent_map(em);
265 /* once for the tree*/
266 free_extent_map(em);
267 }
268 if (split)
269 free_extent_map(split);
270 if (split2)
271 free_extent_map(split2);
272 return 0;
273 }
274
275 /*
276 * this is very complex, but the basic idea is to drop all extents
277 * in the range start - end. hint_block is filled in with a block number
278 * that would be a good hint to the block allocator for this file.
279 *
280 * If an extent intersects the range but is not entirely inside the range
281 * it is either truncated or split. Anything entirely inside the range
282 * is deleted from the tree.
283 *
284 * inline_limit is used to tell this code which offsets in the file to keep
285 * if they contain inline extents.
286 */
287 noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
288 struct btrfs_root *root, struct inode *inode,
289 u64 start, u64 end, u64 locked_end,
290 u64 inline_limit, u64 *hint_byte)
291 {
292 u64 extent_end = 0;
293 u64 search_start = start;
294 u64 ram_bytes = 0;
295 u64 disk_bytenr = 0;
296 u64 orig_locked_end = locked_end;
297 u8 compression;
298 u8 encryption;
299 u16 other_encoding = 0;
300 struct extent_buffer *leaf;
301 struct btrfs_file_extent_item *extent;
302 struct btrfs_path *path;
303 struct btrfs_key key;
304 struct btrfs_file_extent_item old;
305 int keep;
306 int slot;
307 int bookend;
308 int found_type = 0;
309 int found_extent;
310 int found_inline;
311 int recow;
312 int ret;
313
314 inline_limit = 0;
315 btrfs_drop_extent_cache(inode, start, end - 1, 0);
316
317 path = btrfs_alloc_path();
318 if (!path)
319 return -ENOMEM;
320 while (1) {
321 recow = 0;
322 btrfs_release_path(root, path);
323 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
324 search_start, -1);
325 if (ret < 0)
326 goto out;
327 if (ret > 0) {
328 if (path->slots[0] == 0) {
329 ret = 0;
330 goto out;
331 }
332 path->slots[0]--;
333 }
334 next_slot:
335 keep = 0;
336 bookend = 0;
337 found_extent = 0;
338 found_inline = 0;
339 compression = 0;
340 encryption = 0;
341 extent = NULL;
342 leaf = path->nodes[0];
343 slot = path->slots[0];
344 ret = 0;
345 btrfs_item_key_to_cpu(leaf, &key, slot);
346 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
347 key.offset >= end) {
348 goto out;
349 }
350 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
351 key.objectid != inode->i_ino) {
352 goto out;
353 }
354 if (recow) {
355 search_start = max(key.offset, start);
356 continue;
357 }
358 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
359 extent = btrfs_item_ptr(leaf, slot,
360 struct btrfs_file_extent_item);
361 found_type = btrfs_file_extent_type(leaf, extent);
362 compression = btrfs_file_extent_compression(leaf,
363 extent);
364 encryption = btrfs_file_extent_encryption(leaf,
365 extent);
366 other_encoding = btrfs_file_extent_other_encoding(leaf,
367 extent);
368 if (found_type == BTRFS_FILE_EXTENT_REG ||
369 found_type == BTRFS_FILE_EXTENT_PREALLOC) {
370 extent_end =
371 btrfs_file_extent_disk_bytenr(leaf,
372 extent);
373 if (extent_end)
374 *hint_byte = extent_end;
375
376 extent_end = key.offset +
377 btrfs_file_extent_num_bytes(leaf, extent);
378 ram_bytes = btrfs_file_extent_ram_bytes(leaf,
379 extent);
380 found_extent = 1;
381 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
382 found_inline = 1;
383 extent_end = key.offset +
384 btrfs_file_extent_inline_len(leaf, extent);
385 }
386 } else {
387 extent_end = search_start;
388 }
389
390 /* we found nothing we can drop */
391 if ((!found_extent && !found_inline) ||
392 search_start >= extent_end) {
393 int nextret;
394 u32 nritems;
395 nritems = btrfs_header_nritems(leaf);
396 if (slot >= nritems - 1) {
397 nextret = btrfs_next_leaf(root, path);
398 if (nextret)
399 goto out;
400 recow = 1;
401 } else {
402 path->slots[0]++;
403 }
404 goto next_slot;
405 }
406
407 if (end <= extent_end && start >= key.offset && found_inline)
408 *hint_byte = EXTENT_MAP_INLINE;
409
410 if (found_extent) {
411 read_extent_buffer(leaf, &old, (unsigned long)extent,
412 sizeof(old));
413 }
414
415 if (end < extent_end && end >= key.offset) {
416 bookend = 1;
417 if (found_inline && start <= key.offset)
418 keep = 1;
419 }
420
421 if (bookend && found_extent) {
422 if (locked_end < extent_end) {
423 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
424 locked_end, extent_end - 1,
425 GFP_NOFS);
426 if (!ret) {
427 btrfs_release_path(root, path);
428 lock_extent(&BTRFS_I(inode)->io_tree,
429 locked_end, extent_end - 1,
430 GFP_NOFS);
431 locked_end = extent_end;
432 continue;
433 }
434 locked_end = extent_end;
435 }
436 disk_bytenr = le64_to_cpu(old.disk_bytenr);
437 if (disk_bytenr != 0) {
438 ret = btrfs_inc_extent_ref(trans, root,
439 disk_bytenr,
440 le64_to_cpu(old.disk_num_bytes), 0,
441 root->root_key.objectid,
442 key.objectid, key.offset -
443 le64_to_cpu(old.offset));
444 BUG_ON(ret);
445 }
446 }
447
448 if (found_inline) {
449 u64 mask = root->sectorsize - 1;
450 search_start = (extent_end + mask) & ~mask;
451 } else
452 search_start = extent_end;
453
454 /* truncate existing extent */
455 if (start > key.offset) {
456 u64 new_num;
457 u64 old_num;
458 keep = 1;
459 WARN_ON(start & (root->sectorsize - 1));
460 if (found_extent) {
461 new_num = start - key.offset;
462 old_num = btrfs_file_extent_num_bytes(leaf,
463 extent);
464 *hint_byte =
465 btrfs_file_extent_disk_bytenr(leaf,
466 extent);
467 if (btrfs_file_extent_disk_bytenr(leaf,
468 extent)) {
469 inode_sub_bytes(inode, old_num -
470 new_num);
471 }
472 btrfs_set_file_extent_num_bytes(leaf,
473 extent, new_num);
474 btrfs_mark_buffer_dirty(leaf);
475 } else if (key.offset < inline_limit &&
476 (end > extent_end) &&
477 (inline_limit < extent_end)) {
478 u32 new_size;
479 new_size = btrfs_file_extent_calc_inline_size(
480 inline_limit - key.offset);
481 inode_sub_bytes(inode, extent_end -
482 inline_limit);
483 btrfs_set_file_extent_ram_bytes(leaf, extent,
484 new_size);
485 if (!compression && !encryption) {
486 btrfs_truncate_item(trans, root, path,
487 new_size, 1);
488 }
489 }
490 }
491 /* delete the entire extent */
492 if (!keep) {
493 if (found_inline)
494 inode_sub_bytes(inode, extent_end -
495 key.offset);
496 ret = btrfs_del_item(trans, root, path);
497 /* TODO update progress marker and return */
498 BUG_ON(ret);
499 extent = NULL;
500 btrfs_release_path(root, path);
501 /* the extent will be freed later */
502 }
503 if (bookend && found_inline && start <= key.offset) {
504 u32 new_size;
505 new_size = btrfs_file_extent_calc_inline_size(
506 extent_end - end);
507 inode_sub_bytes(inode, end - key.offset);
508 btrfs_set_file_extent_ram_bytes(leaf, extent,
509 new_size);
510 if (!compression && !encryption)
511 ret = btrfs_truncate_item(trans, root, path,
512 new_size, 0);
513 BUG_ON(ret);
514 }
515 /* create bookend, splitting the extent in two */
516 if (bookend && found_extent) {
517 struct btrfs_key ins;
518 ins.objectid = inode->i_ino;
519 ins.offset = end;
520 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
521
522 btrfs_release_path(root, path);
523 path->leave_spinning = 1;
524 ret = btrfs_insert_empty_item(trans, root, path, &ins,
525 sizeof(*extent));
526 BUG_ON(ret);
527
528 leaf = path->nodes[0];
529 extent = btrfs_item_ptr(leaf, path->slots[0],
530 struct btrfs_file_extent_item);
531 write_extent_buffer(leaf, &old,
532 (unsigned long)extent, sizeof(old));
533
534 btrfs_set_file_extent_compression(leaf, extent,
535 compression);
536 btrfs_set_file_extent_encryption(leaf, extent,
537 encryption);
538 btrfs_set_file_extent_other_encoding(leaf, extent,
539 other_encoding);
540 btrfs_set_file_extent_offset(leaf, extent,
541 le64_to_cpu(old.offset) + end - key.offset);
542 WARN_ON(le64_to_cpu(old.num_bytes) <
543 (extent_end - end));
544 btrfs_set_file_extent_num_bytes(leaf, extent,
545 extent_end - end);
546
547 /*
548 * set the ram bytes to the size of the full extent
549 * before splitting. This is a worst case flag,
550 * but its the best we can do because we don't know
551 * how splitting affects compression
552 */
553 btrfs_set_file_extent_ram_bytes(leaf, extent,
554 ram_bytes);
555 btrfs_set_file_extent_type(leaf, extent, found_type);
556
557 btrfs_unlock_up_safe(path, 1);
558 btrfs_mark_buffer_dirty(path->nodes[0]);
559 btrfs_set_lock_blocking(path->nodes[0]);
560
561 path->leave_spinning = 0;
562 btrfs_release_path(root, path);
563 if (disk_bytenr != 0)
564 inode_add_bytes(inode, extent_end - end);
565 }
566
567 if (found_extent && !keep) {
568 u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr);
569
570 if (old_disk_bytenr != 0) {
571 inode_sub_bytes(inode,
572 le64_to_cpu(old.num_bytes));
573 ret = btrfs_free_extent(trans, root,
574 old_disk_bytenr,
575 le64_to_cpu(old.disk_num_bytes),
576 0, root->root_key.objectid,
577 key.objectid, key.offset -
578 le64_to_cpu(old.offset));
579 BUG_ON(ret);
580 *hint_byte = old_disk_bytenr;
581 }
582 }
583
584 if (search_start >= end) {
585 ret = 0;
586 goto out;
587 }
588 }
589 out:
590 btrfs_free_path(path);
591 if (locked_end > orig_locked_end) {
592 unlock_extent(&BTRFS_I(inode)->io_tree, orig_locked_end,
593 locked_end - 1, GFP_NOFS);
594 }
595 return ret;
596 }
597
598 static int extent_mergeable(struct extent_buffer *leaf, int slot,
599 u64 objectid, u64 bytenr, u64 *start, u64 *end)
600 {
601 struct btrfs_file_extent_item *fi;
602 struct btrfs_key key;
603 u64 extent_end;
604
605 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
606 return 0;
607
608 btrfs_item_key_to_cpu(leaf, &key, slot);
609 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
610 return 0;
611
612 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
613 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
614 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
615 btrfs_file_extent_compression(leaf, fi) ||
616 btrfs_file_extent_encryption(leaf, fi) ||
617 btrfs_file_extent_other_encoding(leaf, fi))
618 return 0;
619
620 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
621 if ((*start && *start != key.offset) || (*end && *end != extent_end))
622 return 0;
623
624 *start = key.offset;
625 *end = extent_end;
626 return 1;
627 }
628
629 /*
630 * Mark extent in the range start - end as written.
631 *
632 * This changes extent type from 'pre-allocated' to 'regular'. If only
633 * part of extent is marked as written, the extent will be split into
634 * two or three.
635 */
636 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
637 struct btrfs_root *root,
638 struct inode *inode, u64 start, u64 end)
639 {
640 struct extent_buffer *leaf;
641 struct btrfs_path *path;
642 struct btrfs_file_extent_item *fi;
643 struct btrfs_key key;
644 u64 bytenr;
645 u64 num_bytes;
646 u64 extent_end;
647 u64 orig_offset;
648 u64 other_start;
649 u64 other_end;
650 u64 split = start;
651 u64 locked_end = end;
652 int extent_type;
653 int split_end = 1;
654 int ret;
655
656 btrfs_drop_extent_cache(inode, start, end - 1, 0);
657
658 path = btrfs_alloc_path();
659 BUG_ON(!path);
660 again:
661 key.objectid = inode->i_ino;
662 key.type = BTRFS_EXTENT_DATA_KEY;
663 if (split == start)
664 key.offset = split;
665 else
666 key.offset = split - 1;
667
668 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
669 if (ret > 0 && path->slots[0] > 0)
670 path->slots[0]--;
671
672 leaf = path->nodes[0];
673 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
674 BUG_ON(key.objectid != inode->i_ino ||
675 key.type != BTRFS_EXTENT_DATA_KEY);
676 fi = btrfs_item_ptr(leaf, path->slots[0],
677 struct btrfs_file_extent_item);
678 extent_type = btrfs_file_extent_type(leaf, fi);
679 BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC);
680 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
681 BUG_ON(key.offset > start || extent_end < end);
682
683 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
684 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
685 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
686
687 if (key.offset == start)
688 split = end;
689
690 if (key.offset == start && extent_end == end) {
691 int del_nr = 0;
692 int del_slot = 0;
693 other_start = end;
694 other_end = 0;
695 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
696 bytenr, &other_start, &other_end)) {
697 extent_end = other_end;
698 del_slot = path->slots[0] + 1;
699 del_nr++;
700 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
701 0, root->root_key.objectid,
702 inode->i_ino, orig_offset);
703 BUG_ON(ret);
704 }
705 other_start = 0;
706 other_end = start;
707 if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino,
708 bytenr, &other_start, &other_end)) {
709 key.offset = other_start;
710 del_slot = path->slots[0];
711 del_nr++;
712 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
713 0, root->root_key.objectid,
714 inode->i_ino, orig_offset);
715 BUG_ON(ret);
716 }
717 split_end = 0;
718 if (del_nr == 0) {
719 btrfs_set_file_extent_type(leaf, fi,
720 BTRFS_FILE_EXTENT_REG);
721 goto done;
722 }
723
724 fi = btrfs_item_ptr(leaf, del_slot - 1,
725 struct btrfs_file_extent_item);
726 btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
727 btrfs_set_file_extent_num_bytes(leaf, fi,
728 extent_end - key.offset);
729 btrfs_mark_buffer_dirty(leaf);
730
731 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
732 BUG_ON(ret);
733 goto release;
734 } else if (split == start) {
735 if (locked_end < extent_end) {
736 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
737 locked_end, extent_end - 1, GFP_NOFS);
738 if (!ret) {
739 btrfs_release_path(root, path);
740 lock_extent(&BTRFS_I(inode)->io_tree,
741 locked_end, extent_end - 1, GFP_NOFS);
742 locked_end = extent_end;
743 goto again;
744 }
745 locked_end = extent_end;
746 }
747 btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
748 } else {
749 BUG_ON(key.offset != start);
750 key.offset = split;
751 btrfs_set_file_extent_offset(leaf, fi, key.offset -
752 orig_offset);
753 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
754 btrfs_set_item_key_safe(trans, root, path, &key);
755 extent_end = split;
756 }
757
758 if (extent_end == end) {
759 split_end = 0;
760 extent_type = BTRFS_FILE_EXTENT_REG;
761 }
762 if (extent_end == end && split == start) {
763 other_start = end;
764 other_end = 0;
765 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
766 bytenr, &other_start, &other_end)) {
767 path->slots[0]++;
768 fi = btrfs_item_ptr(leaf, path->slots[0],
769 struct btrfs_file_extent_item);
770 key.offset = split;
771 btrfs_set_item_key_safe(trans, root, path, &key);
772 btrfs_set_file_extent_offset(leaf, fi, key.offset -
773 orig_offset);
774 btrfs_set_file_extent_num_bytes(leaf, fi,
775 other_end - split);
776 goto done;
777 }
778 }
779 if (extent_end == end && split == end) {
780 other_start = 0;
781 other_end = start;
782 if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino,
783 bytenr, &other_start, &other_end)) {
784 path->slots[0]--;
785 fi = btrfs_item_ptr(leaf, path->slots[0],
786 struct btrfs_file_extent_item);
787 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end -
788 other_start);
789 goto done;
790 }
791 }
792
793 btrfs_mark_buffer_dirty(leaf);
794
795 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
796 root->root_key.objectid,
797 inode->i_ino, orig_offset);
798 BUG_ON(ret);
799 btrfs_release_path(root, path);
800
801 key.offset = start;
802 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi));
803 BUG_ON(ret);
804
805 leaf = path->nodes[0];
806 fi = btrfs_item_ptr(leaf, path->slots[0],
807 struct btrfs_file_extent_item);
808 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
809 btrfs_set_file_extent_type(leaf, fi, extent_type);
810 btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr);
811 btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
812 btrfs_set_file_extent_offset(leaf, fi, key.offset - orig_offset);
813 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset);
814 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
815 btrfs_set_file_extent_compression(leaf, fi, 0);
816 btrfs_set_file_extent_encryption(leaf, fi, 0);
817 btrfs_set_file_extent_other_encoding(leaf, fi, 0);
818 done:
819 btrfs_mark_buffer_dirty(leaf);
820
821 release:
822 btrfs_release_path(root, path);
823 if (split_end && split == start) {
824 split = end;
825 goto again;
826 }
827 if (locked_end > end) {
828 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
829 GFP_NOFS);
830 }
831 btrfs_free_path(path);
832 return 0;
833 }
834
835 /*
836 * this gets pages into the page cache and locks them down, it also properly
837 * waits for data=ordered extents to finish before allowing the pages to be
838 * modified.
839 */
840 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
841 struct page **pages, size_t num_pages,
842 loff_t pos, unsigned long first_index,
843 unsigned long last_index, size_t write_bytes)
844 {
845 int i;
846 unsigned long index = pos >> PAGE_CACHE_SHIFT;
847 struct inode *inode = fdentry(file)->d_inode;
848 int err = 0;
849 u64 start_pos;
850 u64 last_pos;
851
852 start_pos = pos & ~((u64)root->sectorsize - 1);
853 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
854
855 if (start_pos > inode->i_size) {
856 err = btrfs_cont_expand(inode, start_pos);
857 if (err)
858 return err;
859 }
860
861 memset(pages, 0, num_pages * sizeof(struct page *));
862 again:
863 for (i = 0; i < num_pages; i++) {
864 pages[i] = grab_cache_page(inode->i_mapping, index + i);
865 if (!pages[i]) {
866 err = -ENOMEM;
867 BUG_ON(1);
868 }
869 wait_on_page_writeback(pages[i]);
870 }
871 if (start_pos < inode->i_size) {
872 struct btrfs_ordered_extent *ordered;
873 lock_extent(&BTRFS_I(inode)->io_tree,
874 start_pos, last_pos - 1, GFP_NOFS);
875 ordered = btrfs_lookup_first_ordered_extent(inode,
876 last_pos - 1);
877 if (ordered &&
878 ordered->file_offset + ordered->len > start_pos &&
879 ordered->file_offset < last_pos) {
880 btrfs_put_ordered_extent(ordered);
881 unlock_extent(&BTRFS_I(inode)->io_tree,
882 start_pos, last_pos - 1, GFP_NOFS);
883 for (i = 0; i < num_pages; i++) {
884 unlock_page(pages[i]);
885 page_cache_release(pages[i]);
886 }
887 btrfs_wait_ordered_range(inode, start_pos,
888 last_pos - start_pos);
889 goto again;
890 }
891 if (ordered)
892 btrfs_put_ordered_extent(ordered);
893
894 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
895 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
896 GFP_NOFS);
897 unlock_extent(&BTRFS_I(inode)->io_tree,
898 start_pos, last_pos - 1, GFP_NOFS);
899 }
900 for (i = 0; i < num_pages; i++) {
901 clear_page_dirty_for_io(pages[i]);
902 set_page_extent_mapped(pages[i]);
903 WARN_ON(!PageLocked(pages[i]));
904 }
905 return 0;
906 }
907
908 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
909 size_t count, loff_t *ppos)
910 {
911 loff_t pos;
912 loff_t start_pos;
913 ssize_t num_written = 0;
914 ssize_t err = 0;
915 int ret = 0;
916 struct inode *inode = fdentry(file)->d_inode;
917 struct btrfs_root *root = BTRFS_I(inode)->root;
918 struct page **pages = NULL;
919 int nrptrs;
920 struct page *pinned[2];
921 unsigned long first_index;
922 unsigned long last_index;
923 int will_write;
924
925 will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) ||
926 (file->f_flags & O_DIRECT));
927
928 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
929 PAGE_CACHE_SIZE / (sizeof(struct page *)));
930 pinned[0] = NULL;
931 pinned[1] = NULL;
932
933 pos = *ppos;
934 start_pos = pos;
935
936 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
937 current->backing_dev_info = inode->i_mapping->backing_dev_info;
938 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
939 if (err)
940 goto out_nolock;
941 if (count == 0)
942 goto out_nolock;
943
944 err = file_remove_suid(file);
945 if (err)
946 goto out_nolock;
947 file_update_time(file);
948
949 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
950
951 mutex_lock(&inode->i_mutex);
952 BTRFS_I(inode)->sequence++;
953 first_index = pos >> PAGE_CACHE_SHIFT;
954 last_index = (pos + count) >> PAGE_CACHE_SHIFT;
955
956 /*
957 * there are lots of better ways to do this, but this code
958 * makes sure the first and last page in the file range are
959 * up to date and ready for cow
960 */
961 if ((pos & (PAGE_CACHE_SIZE - 1))) {
962 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
963 if (!PageUptodate(pinned[0])) {
964 ret = btrfs_readpage(NULL, pinned[0]);
965 BUG_ON(ret);
966 wait_on_page_locked(pinned[0]);
967 } else {
968 unlock_page(pinned[0]);
969 }
970 }
971 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
972 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
973 if (!PageUptodate(pinned[1])) {
974 ret = btrfs_readpage(NULL, pinned[1]);
975 BUG_ON(ret);
976 wait_on_page_locked(pinned[1]);
977 } else {
978 unlock_page(pinned[1]);
979 }
980 }
981
982 while (count > 0) {
983 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
984 size_t write_bytes = min(count, nrptrs *
985 (size_t)PAGE_CACHE_SIZE -
986 offset);
987 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
988 PAGE_CACHE_SHIFT;
989
990 WARN_ON(num_pages > nrptrs);
991 memset(pages, 0, sizeof(struct page *) * nrptrs);
992
993 ret = btrfs_check_data_free_space(root, inode, write_bytes);
994 if (ret)
995 goto out;
996
997 ret = prepare_pages(root, file, pages, num_pages,
998 pos, first_index, last_index,
999 write_bytes);
1000 if (ret) {
1001 btrfs_free_reserved_data_space(root, inode,
1002 write_bytes);
1003 goto out;
1004 }
1005
1006 ret = btrfs_copy_from_user(pos, num_pages,
1007 write_bytes, pages, buf);
1008 if (ret) {
1009 btrfs_free_reserved_data_space(root, inode,
1010 write_bytes);
1011 btrfs_drop_pages(pages, num_pages);
1012 goto out;
1013 }
1014
1015 ret = dirty_and_release_pages(NULL, root, file, pages,
1016 num_pages, pos, write_bytes);
1017 btrfs_drop_pages(pages, num_pages);
1018 if (ret) {
1019 btrfs_free_reserved_data_space(root, inode,
1020 write_bytes);
1021 goto out;
1022 }
1023
1024 if (will_write) {
1025 btrfs_fdatawrite_range(inode->i_mapping, pos,
1026 pos + write_bytes - 1,
1027 WB_SYNC_ALL);
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
1049 out_nolock:
1050 kfree(pages);
1051 if (pinned[0])
1052 page_cache_release(pinned[0]);
1053 if (pinned[1])
1054 page_cache_release(pinned[1]);
1055 *ppos = pos;
1056
1057 /*
1058 * we want to make sure fsync finds this change
1059 * but we haven't joined a transaction running right now.
1060 *
1061 * Later on, someone is sure to update the inode and get the
1062 * real transid recorded.
1063 *
1064 * We set last_trans now to the fs_info generation + 1,
1065 * this will either be one more than the running transaction
1066 * or the generation used for the next transaction if there isn't
1067 * one running right now.
1068 */
1069 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1070
1071 if (num_written > 0 && will_write) {
1072 struct btrfs_trans_handle *trans;
1073
1074 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1075 if (err)
1076 num_written = err;
1077
1078 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
1079 trans = btrfs_start_transaction(root, 1);
1080 ret = btrfs_log_dentry_safe(trans, root,
1081 file->f_dentry);
1082 if (ret == 0) {
1083 ret = btrfs_sync_log(trans, root);
1084 if (ret == 0)
1085 btrfs_end_transaction(trans, root);
1086 else
1087 btrfs_commit_transaction(trans, root);
1088 } else {
1089 btrfs_commit_transaction(trans, root);
1090 }
1091 }
1092 if (file->f_flags & O_DIRECT) {
1093 invalidate_mapping_pages(inode->i_mapping,
1094 start_pos >> PAGE_CACHE_SHIFT,
1095 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1096 }
1097 }
1098 current->backing_dev_info = NULL;
1099 return num_written ? num_written : err;
1100 }
1101
1102 int btrfs_release_file(struct inode *inode, struct file *filp)
1103 {
1104 /*
1105 * ordered_data_close is set by settattr when we are about to truncate
1106 * a file from a non-zero size to a zero size. This tries to
1107 * flush down new bytes that may have been written if the
1108 * application were using truncate to replace a file in place.
1109 */
1110 if (BTRFS_I(inode)->ordered_data_close) {
1111 BTRFS_I(inode)->ordered_data_close = 0;
1112 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1113 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1114 filemap_flush(inode->i_mapping);
1115 }
1116 if (filp->private_data)
1117 btrfs_ioctl_trans_end(filp);
1118 return 0;
1119 }
1120
1121 /*
1122 * fsync call for both files and directories. This logs the inode into
1123 * the tree log instead of forcing full commits whenever possible.
1124 *
1125 * It needs to call filemap_fdatawait so that all ordered extent updates are
1126 * in the metadata btree are up to date for copying to the log.
1127 *
1128 * It drops the inode mutex before doing the tree log commit. This is an
1129 * important optimization for directories because holding the mutex prevents
1130 * new operations on the dir while we write to disk.
1131 */
1132 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
1133 {
1134 struct inode *inode = dentry->d_inode;
1135 struct btrfs_root *root = BTRFS_I(inode)->root;
1136 int ret = 0;
1137 struct btrfs_trans_handle *trans;
1138
1139 /*
1140 * check the transaction that last modified this inode
1141 * and see if its already been committed
1142 */
1143 if (!BTRFS_I(inode)->last_trans)
1144 goto out;
1145
1146 mutex_lock(&root->fs_info->trans_mutex);
1147 if (BTRFS_I(inode)->last_trans <=
1148 root->fs_info->last_trans_committed) {
1149 BTRFS_I(inode)->last_trans = 0;
1150 mutex_unlock(&root->fs_info->trans_mutex);
1151 goto out;
1152 }
1153 mutex_unlock(&root->fs_info->trans_mutex);
1154
1155 root->log_batch++;
1156 filemap_fdatawrite(inode->i_mapping);
1157 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1158 root->log_batch++;
1159
1160 if (datasync && !(inode->i_state & I_DIRTY_PAGES))
1161 goto out;
1162 /*
1163 * ok we haven't committed the transaction yet, lets do a commit
1164 */
1165 if (file && file->private_data)
1166 btrfs_ioctl_trans_end(file);
1167
1168 trans = btrfs_start_transaction(root, 1);
1169 if (!trans) {
1170 ret = -ENOMEM;
1171 goto out;
1172 }
1173
1174 ret = btrfs_log_dentry_safe(trans, root, dentry);
1175 if (ret < 0)
1176 goto out;
1177
1178 /* we've logged all the items and now have a consistent
1179 * version of the file in the log. It is possible that
1180 * someone will come in and modify the file, but that's
1181 * fine because the log is consistent on disk, and we
1182 * have references to all of the file's extents
1183 *
1184 * It is possible that someone will come in and log the
1185 * file again, but that will end up using the synchronization
1186 * inside btrfs_sync_log to keep things safe.
1187 */
1188 mutex_unlock(&dentry->d_inode->i_mutex);
1189
1190 if (ret > 0) {
1191 ret = btrfs_commit_transaction(trans, root);
1192 } else {
1193 ret = btrfs_sync_log(trans, root);
1194 if (ret == 0)
1195 ret = btrfs_end_transaction(trans, root);
1196 else
1197 ret = btrfs_commit_transaction(trans, root);
1198 }
1199 mutex_lock(&dentry->d_inode->i_mutex);
1200 out:
1201 return ret > 0 ? EIO : ret;
1202 }
1203
1204 static struct vm_operations_struct btrfs_file_vm_ops = {
1205 .fault = filemap_fault,
1206 .page_mkwrite = btrfs_page_mkwrite,
1207 };
1208
1209 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1210 {
1211 vma->vm_ops = &btrfs_file_vm_ops;
1212 file_accessed(filp);
1213 return 0;
1214 }
1215
1216 struct file_operations btrfs_file_operations = {
1217 .llseek = generic_file_llseek,
1218 .read = do_sync_read,
1219 .aio_read = generic_file_aio_read,
1220 .splice_read = generic_file_splice_read,
1221 .write = btrfs_file_write,
1222 .mmap = btrfs_file_mmap,
1223 .open = generic_file_open,
1224 .release = btrfs_release_file,
1225 .fsync = btrfs_sync_file,
1226 .unlocked_ioctl = btrfs_ioctl,
1227 #ifdef CONFIG_COMPAT
1228 .compat_ioctl = btrfs_ioctl,
1229 #endif
1230 };
Linus' kernel tree