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checkpatch: if should not continue a preceeding brace
[linux-2.6/mini2440.git] / fs / btrfs / file.c
blob90268334145e30e4abe0390333b98678bf47db29
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 <linux/version.h>
33 #include "ctree.h"
34 #include "disk-io.h"
35 #include "transaction.h"
36 #include "btrfs_inode.h"
37 #include "ioctl.h"
38 #include "print-tree.h"
39 #include "tree-log.h"
40 #include "locking.h"
41 #include "compat.h"
42
43
44 /* simple helper to fault in pages and copy. This should go away
45 * and be replaced with calls into generic code.
46 */
47 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
48 int write_bytes,
49 struct page **prepared_pages,
50 const char __user *buf)
51 {
52 long page_fault = 0;
53 int i;
54 int offset = pos & (PAGE_CACHE_SIZE - 1);
55
56 for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
57 size_t count = min_t(size_t,
58 PAGE_CACHE_SIZE - offset, write_bytes);
59 struct page *page = prepared_pages[i];
60 fault_in_pages_readable(buf, count);
61
62 /* Copy data from userspace to the current page */
63 kmap(page);
64 page_fault = __copy_from_user(page_address(page) + offset,
65 buf, count);
66 /* Flush processor's dcache for this page */
67 flush_dcache_page(page);
68 kunmap(page);
69 buf += count;
70 write_bytes -= count;
71
72 if (page_fault)
73 break;
74 }
75 return page_fault ? -EFAULT : 0;
76 }
77
78 /*
79 * unlocks pages after btrfs_file_write is done with them
80 */
81 static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages)
82 {
83 size_t i;
84 for (i = 0; i < num_pages; i++) {
85 if (!pages[i])
86 break;
87 /* page checked is some magic around finding pages that
88 * have been modified without going through btrfs_set_page_dirty
89 * clear it here
90 */
91 ClearPageChecked(pages[i]);
92 unlock_page(pages[i]);
93 mark_page_accessed(pages[i]);
94 page_cache_release(pages[i]);
95 }
96 }
97
98 /*
99 * after copy_from_user, pages need to be dirtied and we need to make
100 * sure holes are created between the current EOF and the start of
101 * any next extents (if required).
102 *
103 * this also makes the decision about creating an inline extent vs
104 * doing real data extents, marking pages dirty and delalloc as required.
105 */
106 static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
107 struct btrfs_root *root,
108 struct file *file,
109 struct page **pages,
110 size_t num_pages,
111 loff_t pos,
112 size_t write_bytes)
113 {
114 int err = 0;
115 int i;
116 struct inode *inode = fdentry(file)->d_inode;
117 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
118 u64 hint_byte;
119 u64 num_bytes;
120 u64 start_pos;
121 u64 end_of_last_block;
122 u64 end_pos = pos + write_bytes;
123 loff_t isize = i_size_read(inode);
124
125 start_pos = pos & ~((u64)root->sectorsize - 1);
126 num_bytes = (write_bytes + pos - start_pos +
127 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
128
129 end_of_last_block = start_pos + num_bytes - 1;
130
131 lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
132 trans = btrfs_join_transaction(root, 1);
133 if (!trans) {
134 err = -ENOMEM;
135 goto out_unlock;
136 }
137 btrfs_set_trans_block_group(trans, inode);
138 hint_byte = 0;
139
140 set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
141
142 /* check for reserved extents on each page, we don't want
143 * to reset the delalloc bit on things that already have
144 * extents reserved.
145 */
146 btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
147 for (i = 0; i < num_pages; i++) {
148 struct page *p = pages[i];
149 SetPageUptodate(p);
150 ClearPageChecked(p);
151 set_page_dirty(p);
152 }
153 if (end_pos > isize) {
154 i_size_write(inode, end_pos);
155 btrfs_update_inode(trans, root, inode);
156 }
157 err = btrfs_end_transaction(trans, root);
158 out_unlock:
159 unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
160 return err;
161 }
162
163 /*
164 * this drops all the extents in the cache that intersect the range
165 * [start, end]. Existing extents are split as required.
166 */
167 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
168 int skip_pinned)
169 {
170 struct extent_map *em;
171 struct extent_map *split = NULL;
172 struct extent_map *split2 = NULL;
173 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
174 u64 len = end - start + 1;
175 int ret;
176 int testend = 1;
177 unsigned long flags;
178 int compressed = 0;
179
180 WARN_ON(end < start);
181 if (end == (u64)-1) {
182 len = (u64)-1;
183 testend = 0;
184 }
185 while (1) {
186 if (!split)
187 split = alloc_extent_map(GFP_NOFS);
188 if (!split2)
189 split2 = alloc_extent_map(GFP_NOFS);
190
191 spin_lock(&em_tree->lock);
192 em = lookup_extent_mapping(em_tree, start, len);
193 if (!em) {
194 spin_unlock(&em_tree->lock);
195 break;
196 }
197 flags = em->flags;
198 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
199 spin_unlock(&em_tree->lock);
200 if (em->start <= start &&
201 (!testend || em->start + em->len >= start + len)) {
202 free_extent_map(em);
203 break;
204 }
205 if (start < em->start) {
206 len = em->start - start;
207 } else {
208 len = start + len - (em->start + em->len);
209 start = em->start + em->len;
210 }
211 free_extent_map(em);
212 continue;
213 }
214 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
215 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
216 remove_extent_mapping(em_tree, em);
217
218 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
219 em->start < start) {
220 split->start = em->start;
221 split->len = start - em->start;
222 split->orig_start = em->orig_start;
223 split->block_start = em->block_start;
224
225 if (compressed)
226 split->block_len = em->block_len;
227 else
228 split->block_len = split->len;
229
230 split->bdev = em->bdev;
231 split->flags = flags;
232 ret = add_extent_mapping(em_tree, split);
233 BUG_ON(ret);
234 free_extent_map(split);
235 split = split2;
236 split2 = NULL;
237 }
238 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
239 testend && em->start + em->len > start + len) {
240 u64 diff = start + len - em->start;
241
242 split->start = start + len;
243 split->len = em->start + em->len - (start + len);
244 split->bdev = em->bdev;
245 split->flags = flags;
246
247 if (compressed) {
248 split->block_len = em->block_len;
249 split->block_start = em->block_start;
250 split->orig_start = em->orig_start;
251 } else {
252 split->block_len = split->len;
253 split->block_start = em->block_start + diff;
254 split->orig_start = split->start;
255 }
256
257 ret = add_extent_mapping(em_tree, split);
258 BUG_ON(ret);
259 free_extent_map(split);
260 split = NULL;
261 }
262 spin_unlock(&em_tree->lock);
263
264 /* once for us */
265 free_extent_map(em);
266 /* once for the tree*/
267 free_extent_map(em);
268 }
269 if (split)
270 free_extent_map(split);
271 if (split2)
272 free_extent_map(split2);
273 return 0;
274 }
275
276 int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
277 {
278 return 0;
279 #if 0
280 struct btrfs_path *path;
281 struct btrfs_key found_key;
282 struct extent_buffer *leaf;
283 struct btrfs_file_extent_item *extent;
284 u64 last_offset = 0;
285 int nritems;
286 int slot;
287 int found_type;
288 int ret;
289 int err = 0;
290 u64 extent_end = 0;
291
292 path = btrfs_alloc_path();
293 ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
294 last_offset, 0);
295 while (1) {
296 nritems = btrfs_header_nritems(path->nodes[0]);
297 if (path->slots[0] >= nritems) {
298 ret = btrfs_next_leaf(root, path);
299 if (ret)
300 goto out;
301 nritems = btrfs_header_nritems(path->nodes[0]);
302 }
303 slot = path->slots[0];
304 leaf = path->nodes[0];
305 btrfs_item_key_to_cpu(leaf, &found_key, slot);
306 if (found_key.objectid != inode->i_ino)
307 break;
308 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
309 goto out;
310
311 if (found_key.offset < last_offset) {
312 WARN_ON(1);
313 btrfs_print_leaf(root, leaf);
314 printk(KERN_ERR "inode %lu found offset %llu "
315 "expected %llu\n", inode->i_ino,
316 (unsigned long long)found_key.offset,
317 (unsigned long long)last_offset);
318 err = 1;
319 goto out;
320 }
321 extent = btrfs_item_ptr(leaf, slot,
322 struct btrfs_file_extent_item);
323 found_type = btrfs_file_extent_type(leaf, extent);
324 if (found_type == BTRFS_FILE_EXTENT_REG) {
325 extent_end = found_key.offset +
326 btrfs_file_extent_num_bytes(leaf, extent);
327 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
328 struct btrfs_item *item;
329 item = btrfs_item_nr(leaf, slot);
330 extent_end = found_key.offset +
331 btrfs_file_extent_inline_len(leaf, extent);
332 extent_end = (extent_end + root->sectorsize - 1) &
333 ~((u64)root->sectorsize - 1);
334 }
335 last_offset = extent_end;
336 path->slots[0]++;
337 }
338 if (0 && last_offset < inode->i_size) {
339 WARN_ON(1);
340 btrfs_print_leaf(root, leaf);
341 printk(KERN_ERR "inode %lu found offset %llu size %llu\n",
342 inode->i_ino, (unsigned long long)last_offset,
343 (unsigned long long)inode->i_size);
344 err = 1;
345
346 }
347 out:
348 btrfs_free_path(path);
349 return err;
350 #endif
351 }
352
353 /*
354 * this is very complex, but the basic idea is to drop all extents
355 * in the range start - end. hint_block is filled in with a block number
356 * that would be a good hint to the block allocator for this file.
357 *
358 * If an extent intersects the range but is not entirely inside the range
359 * it is either truncated or split. Anything entirely inside the range
360 * is deleted from the tree.
361 *
362 * inline_limit is used to tell this code which offsets in the file to keep
363 * if they contain inline extents.
364 */
365 noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
366 struct btrfs_root *root, struct inode *inode,
367 u64 start, u64 end, u64 inline_limit, u64 *hint_byte)
368 {
369 u64 extent_end = 0;
370 u64 locked_end = end;
371 u64 search_start = start;
372 u64 leaf_start;
373 u64 ram_bytes = 0;
374 u64 orig_parent = 0;
375 u64 disk_bytenr = 0;
376 u8 compression;
377 u8 encryption;
378 u16 other_encoding = 0;
379 u64 root_gen;
380 u64 root_owner;
381 struct extent_buffer *leaf;
382 struct btrfs_file_extent_item *extent;
383 struct btrfs_path *path;
384 struct btrfs_key key;
385 struct btrfs_file_extent_item old;
386 int keep;
387 int slot;
388 int bookend;
389 int found_type = 0;
390 int found_extent;
391 int found_inline;
392 int recow;
393 int ret;
394
395 inline_limit = 0;
396 btrfs_drop_extent_cache(inode, start, end - 1, 0);
397
398 path = btrfs_alloc_path();
399 if (!path)
400 return -ENOMEM;
401 while (1) {
402 recow = 0;
403 btrfs_release_path(root, path);
404 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
405 search_start, -1);
406 if (ret < 0)
407 goto out;
408 if (ret > 0) {
409 if (path->slots[0] == 0) {
410 ret = 0;
411 goto out;
412 }
413 path->slots[0]--;
414 }
415 next_slot:
416 keep = 0;
417 bookend = 0;
418 found_extent = 0;
419 found_inline = 0;
420 leaf_start = 0;
421 root_gen = 0;
422 root_owner = 0;
423 compression = 0;
424 encryption = 0;
425 extent = NULL;
426 leaf = path->nodes[0];
427 slot = path->slots[0];
428 ret = 0;
429 btrfs_item_key_to_cpu(leaf, &key, slot);
430 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
431 key.offset >= end) {
432 goto out;
433 }
434 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
435 key.objectid != inode->i_ino) {
436 goto out;
437 }
438 if (recow) {
439 search_start = max(key.offset, start);
440 continue;
441 }
442 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
443 extent = btrfs_item_ptr(leaf, slot,
444 struct btrfs_file_extent_item);
445 found_type = btrfs_file_extent_type(leaf, extent);
446 compression = btrfs_file_extent_compression(leaf,
447 extent);
448 encryption = btrfs_file_extent_encryption(leaf,
449 extent);
450 other_encoding = btrfs_file_extent_other_encoding(leaf,
451 extent);
452 if (found_type == BTRFS_FILE_EXTENT_REG ||
453 found_type == BTRFS_FILE_EXTENT_PREALLOC) {
454 extent_end =
455 btrfs_file_extent_disk_bytenr(leaf,
456 extent);
457 if (extent_end)
458 *hint_byte = extent_end;
459
460 extent_end = key.offset +
461 btrfs_file_extent_num_bytes(leaf, extent);
462 ram_bytes = btrfs_file_extent_ram_bytes(leaf,
463 extent);
464 found_extent = 1;
465 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
466 found_inline = 1;
467 extent_end = key.offset +
468 btrfs_file_extent_inline_len(leaf, extent);
469 }
470 } else {
471 extent_end = search_start;
472 }
473
474 /* we found nothing we can drop */
475 if ((!found_extent && !found_inline) ||
476 search_start >= extent_end) {
477 int nextret;
478 u32 nritems;
479 nritems = btrfs_header_nritems(leaf);
480 if (slot >= nritems - 1) {
481 nextret = btrfs_next_leaf(root, path);
482 if (nextret)
483 goto out;
484 recow = 1;
485 } else {
486 path->slots[0]++;
487 }
488 goto next_slot;
489 }
490
491 if (end <= extent_end && start >= key.offset && found_inline)
492 *hint_byte = EXTENT_MAP_INLINE;
493
494 if (found_extent) {
495 read_extent_buffer(leaf, &old, (unsigned long)extent,
496 sizeof(old));
497 root_gen = btrfs_header_generation(leaf);
498 root_owner = btrfs_header_owner(leaf);
499 leaf_start = leaf->start;
500 }
501
502 if (end < extent_end && end >= key.offset) {
503 bookend = 1;
504 if (found_inline && start <= key.offset)
505 keep = 1;
506 }
507
508 if (bookend && found_extent) {
509 if (locked_end < extent_end) {
510 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
511 locked_end, extent_end - 1,
512 GFP_NOFS);
513 if (!ret) {
514 btrfs_release_path(root, path);
515 lock_extent(&BTRFS_I(inode)->io_tree,
516 locked_end, extent_end - 1,
517 GFP_NOFS);
518 locked_end = extent_end;
519 continue;
520 }
521 locked_end = extent_end;
522 }
523 orig_parent = path->nodes[0]->start;
524 disk_bytenr = le64_to_cpu(old.disk_bytenr);
525 if (disk_bytenr != 0) {
526 ret = btrfs_inc_extent_ref(trans, root,
527 disk_bytenr,
528 le64_to_cpu(old.disk_num_bytes),
529 orig_parent, root->root_key.objectid,
530 trans->transid, inode->i_ino);
531 BUG_ON(ret);
532 }
533 }
534
535 if (found_inline) {
536 u64 mask = root->sectorsize - 1;
537 search_start = (extent_end + mask) & ~mask;
538 } else
539 search_start = extent_end;
540
541 /* truncate existing extent */
542 if (start > key.offset) {
543 u64 new_num;
544 u64 old_num;
545 keep = 1;
546 WARN_ON(start & (root->sectorsize - 1));
547 if (found_extent) {
548 new_num = start - key.offset;
549 old_num = btrfs_file_extent_num_bytes(leaf,
550 extent);
551 *hint_byte =
552 btrfs_file_extent_disk_bytenr(leaf,
553 extent);
554 if (btrfs_file_extent_disk_bytenr(leaf,
555 extent)) {
556 inode_sub_bytes(inode, old_num -
557 new_num);
558 }
559 btrfs_set_file_extent_num_bytes(leaf,
560 extent, new_num);
561 btrfs_mark_buffer_dirty(leaf);
562 } else if (key.offset < inline_limit &&
563 (end > extent_end) &&
564 (inline_limit < extent_end)) {
565 u32 new_size;
566 new_size = btrfs_file_extent_calc_inline_size(
567 inline_limit - key.offset);
568 inode_sub_bytes(inode, extent_end -
569 inline_limit);
570 btrfs_set_file_extent_ram_bytes(leaf, extent,
571 new_size);
572 if (!compression && !encryption) {
573 btrfs_truncate_item(trans, root, path,
574 new_size, 1);
575 }
576 }
577 }
578 /* delete the entire extent */
579 if (!keep) {
580 if (found_inline)
581 inode_sub_bytes(inode, extent_end -
582 key.offset);
583 ret = btrfs_del_item(trans, root, path);
584 /* TODO update progress marker and return */
585 BUG_ON(ret);
586 extent = NULL;
587 btrfs_release_path(root, path);
588 /* the extent will be freed later */
589 }
590 if (bookend && found_inline && start <= key.offset) {
591 u32 new_size;
592 new_size = btrfs_file_extent_calc_inline_size(
593 extent_end - end);
594 inode_sub_bytes(inode, end - key.offset);
595 btrfs_set_file_extent_ram_bytes(leaf, extent,
596 new_size);
597 if (!compression && !encryption)
598 ret = btrfs_truncate_item(trans, root, path,
599 new_size, 0);
600 BUG_ON(ret);
601 }
602 /* create bookend, splitting the extent in two */
603 if (bookend && found_extent) {
604 struct btrfs_key ins;
605 ins.objectid = inode->i_ino;
606 ins.offset = end;
607 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
608
609 btrfs_release_path(root, path);
610 ret = btrfs_insert_empty_item(trans, root, path, &ins,
611 sizeof(*extent));
612 BUG_ON(ret);
613
614 leaf = path->nodes[0];
615 extent = btrfs_item_ptr(leaf, path->slots[0],
616 struct btrfs_file_extent_item);
617 write_extent_buffer(leaf, &old,
618 (unsigned long)extent, sizeof(old));
619
620 btrfs_set_file_extent_compression(leaf, extent,
621 compression);
622 btrfs_set_file_extent_encryption(leaf, extent,
623 encryption);
624 btrfs_set_file_extent_other_encoding(leaf, extent,
625 other_encoding);
626 btrfs_set_file_extent_offset(leaf, extent,
627 le64_to_cpu(old.offset) + end - key.offset);
628 WARN_ON(le64_to_cpu(old.num_bytes) <
629 (extent_end - end));
630 btrfs_set_file_extent_num_bytes(leaf, extent,
631 extent_end - end);
632
633 /*
634 * set the ram bytes to the size of the full extent
635 * before splitting. This is a worst case flag,
636 * but its the best we can do because we don't know
637 * how splitting affects compression
638 */
639 btrfs_set_file_extent_ram_bytes(leaf, extent,
640 ram_bytes);
641 btrfs_set_file_extent_type(leaf, extent, found_type);
642
643 btrfs_mark_buffer_dirty(path->nodes[0]);
644
645 if (disk_bytenr != 0) {
646 ret = btrfs_update_extent_ref(trans, root,
647 disk_bytenr, orig_parent,
648 leaf->start,
649 root->root_key.objectid,
650 trans->transid, ins.objectid);
651
652 BUG_ON(ret);
653 }
654 btrfs_release_path(root, path);
655 if (disk_bytenr != 0)
656 inode_add_bytes(inode, extent_end - end);
657 }
658
659 if (found_extent && !keep) {
660 u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr);
661
662 if (old_disk_bytenr != 0) {
663 inode_sub_bytes(inode,
664 le64_to_cpu(old.num_bytes));
665 ret = btrfs_free_extent(trans, root,
666 old_disk_bytenr,
667 le64_to_cpu(old.disk_num_bytes),
668 leaf_start, root_owner,
669 root_gen, key.objectid, 0);
670 BUG_ON(ret);
671 *hint_byte = old_disk_bytenr;
672 }
673 }
674
675 if (search_start >= end) {
676 ret = 0;
677 goto out;
678 }
679 }
680 out:
681 btrfs_free_path(path);
682 if (locked_end > end) {
683 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
684 GFP_NOFS);
685 }
686 btrfs_check_file(root, inode);
687 return ret;
688 }
689
690 static int extent_mergeable(struct extent_buffer *leaf, int slot,
691 u64 objectid, u64 bytenr, u64 *start, u64 *end)
692 {
693 struct btrfs_file_extent_item *fi;
694 struct btrfs_key key;
695 u64 extent_end;
696
697 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
698 return 0;
699
700 btrfs_item_key_to_cpu(leaf, &key, slot);
701 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
702 return 0;
703
704 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
705 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
706 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
707 btrfs_file_extent_compression(leaf, fi) ||
708 btrfs_file_extent_encryption(leaf, fi) ||
709 btrfs_file_extent_other_encoding(leaf, fi))
710 return 0;
711
712 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
713 if ((*start && *start != key.offset) || (*end && *end != extent_end))
714 return 0;
715
716 *start = key.offset;
717 *end = extent_end;
718 return 1;
719 }
720
721 /*
722 * Mark extent in the range start - end as written.
723 *
724 * This changes extent type from 'pre-allocated' to 'regular'. If only
725 * part of extent is marked as written, the extent will be split into
726 * two or three.
727 */
728 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
729 struct btrfs_root *root,
730 struct inode *inode, u64 start, u64 end)
731 {
732 struct extent_buffer *leaf;
733 struct btrfs_path *path;
734 struct btrfs_file_extent_item *fi;
735 struct btrfs_key key;
736 u64 bytenr;
737 u64 num_bytes;
738 u64 extent_end;
739 u64 extent_offset;
740 u64 other_start;
741 u64 other_end;
742 u64 split = start;
743 u64 locked_end = end;
744 u64 orig_parent;
745 int extent_type;
746 int split_end = 1;
747 int ret;
748
749 btrfs_drop_extent_cache(inode, start, end - 1, 0);
750
751 path = btrfs_alloc_path();
752 BUG_ON(!path);
753 again:
754 key.objectid = inode->i_ino;
755 key.type = BTRFS_EXTENT_DATA_KEY;
756 if (split == start)
757 key.offset = split;
758 else
759 key.offset = split - 1;
760
761 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
762 if (ret > 0 && path->slots[0] > 0)
763 path->slots[0]--;
764
765 leaf = path->nodes[0];
766 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
767 BUG_ON(key.objectid != inode->i_ino ||
768 key.type != BTRFS_EXTENT_DATA_KEY);
769 fi = btrfs_item_ptr(leaf, path->slots[0],
770 struct btrfs_file_extent_item);
771 extent_type = btrfs_file_extent_type(leaf, fi);
772 BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC);
773 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
774 BUG_ON(key.offset > start || extent_end < end);
775
776 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
777 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
778 extent_offset = btrfs_file_extent_offset(leaf, fi);
779
780 if (key.offset == start)
781 split = end;
782
783 if (key.offset == start && extent_end == end) {
784 int del_nr = 0;
785 int del_slot = 0;
786 u64 leaf_owner = btrfs_header_owner(leaf);
787 u64 leaf_gen = btrfs_header_generation(leaf);
788 other_start = end;
789 other_end = 0;
790 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
791 bytenr, &other_start, &other_end)) {
792 extent_end = other_end;
793 del_slot = path->slots[0] + 1;
794 del_nr++;
795 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
796 leaf->start, leaf_owner,
797 leaf_gen, inode->i_ino, 0);
798 BUG_ON(ret);
799 }
800 other_start = 0;
801 other_end = start;
802 if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino,
803 bytenr, &other_start, &other_end)) {
804 key.offset = other_start;
805 del_slot = path->slots[0];
806 del_nr++;
807 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
808 leaf->start, leaf_owner,
809 leaf_gen, inode->i_ino, 0);
810 BUG_ON(ret);
811 }
812 split_end = 0;
813 if (del_nr == 0) {
814 btrfs_set_file_extent_type(leaf, fi,
815 BTRFS_FILE_EXTENT_REG);
816 goto done;
817 }
818
819 fi = btrfs_item_ptr(leaf, del_slot - 1,
820 struct btrfs_file_extent_item);
821 btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
822 btrfs_set_file_extent_num_bytes(leaf, fi,
823 extent_end - key.offset);
824 btrfs_mark_buffer_dirty(leaf);
825
826 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
827 BUG_ON(ret);
828 goto done;
829 } else if (split == start) {
830 if (locked_end < extent_end) {
831 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
832 locked_end, extent_end - 1, GFP_NOFS);
833 if (!ret) {
834 btrfs_release_path(root, path);
835 lock_extent(&BTRFS_I(inode)->io_tree,
836 locked_end, extent_end - 1, GFP_NOFS);
837 locked_end = extent_end;
838 goto again;
839 }
840 locked_end = extent_end;
841 }
842 btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
843 extent_offset += split - key.offset;
844 } else {
845 BUG_ON(key.offset != start);
846 btrfs_set_file_extent_offset(leaf, fi, extent_offset +
847 split - key.offset);
848 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
849 key.offset = split;
850 btrfs_set_item_key_safe(trans, root, path, &key);
851 extent_end = split;
852 }
853
854 if (extent_end == end) {
855 split_end = 0;
856 extent_type = BTRFS_FILE_EXTENT_REG;
857 }
858 if (extent_end == end && split == start) {
859 other_start = end;
860 other_end = 0;
861 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
862 bytenr, &other_start, &other_end)) {
863 path->slots[0]++;
864 fi = btrfs_item_ptr(leaf, path->slots[0],
865 struct btrfs_file_extent_item);
866 key.offset = split;
867 btrfs_set_item_key_safe(trans, root, path, &key);
868 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
869 btrfs_set_file_extent_num_bytes(leaf, fi,
870 other_end - split);
871 goto done;
872 }
873 }
874 if (extent_end == end && split == end) {
875 other_start = 0;
876 other_end = start;
877 if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino,
878 bytenr, &other_start, &other_end)) {
879 path->slots[0]--;
880 fi = btrfs_item_ptr(leaf, path->slots[0],
881 struct btrfs_file_extent_item);
882 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end -
883 other_start);
884 goto done;
885 }
886 }
887
888 btrfs_mark_buffer_dirty(leaf);
889
890 orig_parent = leaf->start;
891 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
892 orig_parent, root->root_key.objectid,
893 trans->transid, inode->i_ino);
894 BUG_ON(ret);
895 btrfs_release_path(root, path);
896
897 key.offset = start;
898 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi));
899 BUG_ON(ret);
900
901 leaf = path->nodes[0];
902 fi = btrfs_item_ptr(leaf, path->slots[0],
903 struct btrfs_file_extent_item);
904 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
905 btrfs_set_file_extent_type(leaf, fi, extent_type);
906 btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr);
907 btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
908 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
909 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset);
910 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
911 btrfs_set_file_extent_compression(leaf, fi, 0);
912 btrfs_set_file_extent_encryption(leaf, fi, 0);
913 btrfs_set_file_extent_other_encoding(leaf, fi, 0);
914
915 if (orig_parent != leaf->start) {
916 ret = btrfs_update_extent_ref(trans, root, bytenr,
917 orig_parent, leaf->start,
918 root->root_key.objectid,
919 trans->transid, inode->i_ino);
920 BUG_ON(ret);
921 }
922 done:
923 btrfs_mark_buffer_dirty(leaf);
924 btrfs_release_path(root, path);
925 if (split_end && split == start) {
926 split = end;
927 goto again;
928 }
929 if (locked_end > end) {
930 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
931 GFP_NOFS);
932 }
933 btrfs_free_path(path);
934 return 0;
935 }
936
937 /*
938 * this gets pages into the page cache and locks them down, it also properly
939 * waits for data=ordered extents to finish before allowing the pages to be
940 * modified.
941 */
942 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
943 struct page **pages, size_t num_pages,
944 loff_t pos, unsigned long first_index,
945 unsigned long last_index, size_t write_bytes)
946 {
947 int i;
948 unsigned long index = pos >> PAGE_CACHE_SHIFT;
949 struct inode *inode = fdentry(file)->d_inode;
950 int err = 0;
951 u64 start_pos;
952 u64 last_pos;
953
954 start_pos = pos & ~((u64)root->sectorsize - 1);
955 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
956
957 if (start_pos > inode->i_size) {
958 err = btrfs_cont_expand(inode, start_pos);
959 if (err)
960 return err;
961 }
962
963 memset(pages, 0, num_pages * sizeof(struct page *));
964 again:
965 for (i = 0; i < num_pages; i++) {
966 pages[i] = grab_cache_page(inode->i_mapping, index + i);
967 if (!pages[i]) {
968 err = -ENOMEM;
969 BUG_ON(1);
970 }
971 wait_on_page_writeback(pages[i]);
972 }
973 if (start_pos < inode->i_size) {
974 struct btrfs_ordered_extent *ordered;
975 lock_extent(&BTRFS_I(inode)->io_tree,
976 start_pos, last_pos - 1, GFP_NOFS);
977 ordered = btrfs_lookup_first_ordered_extent(inode,
978 last_pos - 1);
979 if (ordered &&
980 ordered->file_offset + ordered->len > start_pos &&
981 ordered->file_offset < last_pos) {
982 btrfs_put_ordered_extent(ordered);
983 unlock_extent(&BTRFS_I(inode)->io_tree,
984 start_pos, last_pos - 1, GFP_NOFS);
985 for (i = 0; i < num_pages; i++) {
986 unlock_page(pages[i]);
987 page_cache_release(pages[i]);
988 }
989 btrfs_wait_ordered_range(inode, start_pos,
990 last_pos - start_pos);
991 goto again;
992 }
993 if (ordered)
994 btrfs_put_ordered_extent(ordered);
995
996 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
997 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
998 GFP_NOFS);
999 unlock_extent(&BTRFS_I(inode)->io_tree,
1000 start_pos, last_pos - 1, GFP_NOFS);
1001 }
1002 for (i = 0; i < num_pages; i++) {
1003 clear_page_dirty_for_io(pages[i]);
1004 set_page_extent_mapped(pages[i]);
1005 WARN_ON(!PageLocked(pages[i]));
1006 }
1007 return 0;
1008 }
1009
1010 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
1011 size_t count, loff_t *ppos)
1012 {
1013 loff_t pos;
1014 loff_t start_pos;
1015 ssize_t num_written = 0;
1016 ssize_t err = 0;
1017 int ret = 0;
1018 struct inode *inode = fdentry(file)->d_inode;
1019 struct btrfs_root *root = BTRFS_I(inode)->root;
1020 struct page **pages = NULL;
1021 int nrptrs;
1022 struct page *pinned[2];
1023 unsigned long first_index;
1024 unsigned long last_index;
1025 int will_write;
1026
1027 will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) ||
1028 (file->f_flags & O_DIRECT));
1029
1030 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
1031 PAGE_CACHE_SIZE / (sizeof(struct page *)));
1032 pinned[0] = NULL;
1033 pinned[1] = NULL;
1034
1035 pos = *ppos;
1036 start_pos = pos;
1037
1038 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
1039 current->backing_dev_info = inode->i_mapping->backing_dev_info;
1040 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1041 if (err)
1042 goto out_nolock;
1043 if (count == 0)
1044 goto out_nolock;
1045
1046 err = file_remove_suid(file);
1047 if (err)
1048 goto out_nolock;
1049 file_update_time(file);
1050
1051 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1052
1053 mutex_lock(&inode->i_mutex);
1054 BTRFS_I(inode)->sequence++;
1055 first_index = pos >> PAGE_CACHE_SHIFT;
1056 last_index = (pos + count) >> PAGE_CACHE_SHIFT;
1057
1058 /*
1059 * there are lots of better ways to do this, but this code
1060 * makes sure the first and last page in the file range are
1061 * up to date and ready for cow
1062 */
1063 if ((pos & (PAGE_CACHE_SIZE - 1))) {
1064 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
1065 if (!PageUptodate(pinned[0])) {
1066 ret = btrfs_readpage(NULL, pinned[0]);
1067 BUG_ON(ret);
1068 wait_on_page_locked(pinned[0]);
1069 } else {
1070 unlock_page(pinned[0]);
1071 }
1072 }
1073 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
1074 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
1075 if (!PageUptodate(pinned[1])) {
1076 ret = btrfs_readpage(NULL, pinned[1]);
1077 BUG_ON(ret);
1078 wait_on_page_locked(pinned[1]);
1079 } else {
1080 unlock_page(pinned[1]);
1081 }
1082 }
1083
1084 while (count > 0) {
1085 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1086 size_t write_bytes = min(count, nrptrs *
1087 (size_t)PAGE_CACHE_SIZE -
1088 offset);
1089 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
1090 PAGE_CACHE_SHIFT;
1091
1092 WARN_ON(num_pages > nrptrs);
1093 memset(pages, 0, sizeof(struct page *) * nrptrs);
1094
1095 ret = btrfs_check_free_space(root, write_bytes, 0);
1096 if (ret)
1097 goto out;
1098
1099 ret = prepare_pages(root, file, pages, num_pages,
1100 pos, first_index, last_index,
1101 write_bytes);
1102 if (ret)
1103 goto out;
1104
1105 ret = btrfs_copy_from_user(pos, num_pages,
1106 write_bytes, pages, buf);
1107 if (ret) {
1108 btrfs_drop_pages(pages, num_pages);
1109 goto out;
1110 }
1111
1112 ret = dirty_and_release_pages(NULL, root, file, pages,
1113 num_pages, pos, write_bytes);
1114 btrfs_drop_pages(pages, num_pages);
1115 if (ret)
1116 goto out;
1117
1118 if (will_write) {
1119 btrfs_fdatawrite_range(inode->i_mapping, pos,
1120 pos + write_bytes - 1,
1121 WB_SYNC_NONE);
1122 } else {
1123 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1124 num_pages);
1125 if (num_pages <
1126 (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1127 btrfs_btree_balance_dirty(root, 1);
1128 btrfs_throttle(root);
1129 }
1130
1131 buf += write_bytes;
1132 count -= write_bytes;
1133 pos += write_bytes;
1134 num_written += write_bytes;
1135
1136 cond_resched();
1137 }
1138 out:
1139 mutex_unlock(&inode->i_mutex);
1140
1141 out_nolock:
1142 kfree(pages);
1143 if (pinned[0])
1144 page_cache_release(pinned[0]);
1145 if (pinned[1])
1146 page_cache_release(pinned[1]);
1147 *ppos = pos;
1148
1149 if (num_written > 0 && will_write) {
1150 struct btrfs_trans_handle *trans;
1151
1152 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1153 if (err)
1154 num_written = err;
1155
1156 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
1157 trans = btrfs_start_transaction(root, 1);
1158 ret = btrfs_log_dentry_safe(trans, root,
1159 file->f_dentry);
1160 if (ret == 0) {
1161 btrfs_sync_log(trans, root);
1162 btrfs_end_transaction(trans, root);
1163 } else {
1164 btrfs_commit_transaction(trans, root);
1165 }
1166 }
1167 if (file->f_flags & O_DIRECT) {
1168 invalidate_mapping_pages(inode->i_mapping,
1169 start_pos >> PAGE_CACHE_SHIFT,
1170 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1171 }
1172 }
1173 current->backing_dev_info = NULL;
1174 return num_written ? num_written : err;
1175 }
1176
1177 int btrfs_release_file(struct inode *inode, struct file *filp)
1178 {
1179 if (filp->private_data)
1180 btrfs_ioctl_trans_end(filp);
1181 return 0;
1182 }
1183
1184 /*
1185 * fsync call for both files and directories. This logs the inode into
1186 * the tree log instead of forcing full commits whenever possible.
1187 *
1188 * It needs to call filemap_fdatawait so that all ordered extent updates are
1189 * in the metadata btree are up to date for copying to the log.
1190 *
1191 * It drops the inode mutex before doing the tree log commit. This is an
1192 * important optimization for directories because holding the mutex prevents
1193 * new operations on the dir while we write to disk.
1194 */
1195 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
1196 {
1197 struct inode *inode = dentry->d_inode;
1198 struct btrfs_root *root = BTRFS_I(inode)->root;
1199 int ret = 0;
1200 struct btrfs_trans_handle *trans;
1201
1202 /*
1203 * check the transaction that last modified this inode
1204 * and see if its already been committed
1205 */
1206 if (!BTRFS_I(inode)->last_trans)
1207 goto out;
1208
1209 mutex_lock(&root->fs_info->trans_mutex);
1210 if (BTRFS_I(inode)->last_trans <=
1211 root->fs_info->last_trans_committed) {
1212 BTRFS_I(inode)->last_trans = 0;
1213 mutex_unlock(&root->fs_info->trans_mutex);
1214 goto out;
1215 }
1216 mutex_unlock(&root->fs_info->trans_mutex);
1217
1218 root->fs_info->tree_log_batch++;
1219 filemap_fdatawrite(inode->i_mapping);
1220 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1221 root->fs_info->tree_log_batch++;
1222
1223 /*
1224 * ok we haven't committed the transaction yet, lets do a commit
1225 */
1226 if (file->private_data)
1227 btrfs_ioctl_trans_end(file);
1228
1229 trans = btrfs_start_transaction(root, 1);
1230 if (!trans) {
1231 ret = -ENOMEM;
1232 goto out;
1233 }
1234
1235 ret = btrfs_log_dentry_safe(trans, root, file->f_dentry);
1236 if (ret < 0)
1237 goto out;
1238
1239 /* we've logged all the items and now have a consistent
1240 * version of the file in the log. It is possible that
1241 * someone will come in and modify the file, but that's
1242 * fine because the log is consistent on disk, and we
1243 * have references to all of the file's extents
1244 *
1245 * It is possible that someone will come in and log the
1246 * file again, but that will end up using the synchronization
1247 * inside btrfs_sync_log to keep things safe.
1248 */
1249 mutex_unlock(&file->f_dentry->d_inode->i_mutex);
1250
1251 if (ret > 0) {
1252 ret = btrfs_commit_transaction(trans, root);
1253 } else {
1254 btrfs_sync_log(trans, root);
1255 ret = btrfs_end_transaction(trans, root);
1256 }
1257 mutex_lock(&file->f_dentry->d_inode->i_mutex);
1258 out:
1259 return ret > 0 ? EIO : ret;
1260 }
1261
1262 static struct vm_operations_struct btrfs_file_vm_ops = {
1263 .fault = filemap_fault,
1264 .page_mkwrite = btrfs_page_mkwrite,
1265 };
1266
1267 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1268 {
1269 vma->vm_ops = &btrfs_file_vm_ops;
1270 file_accessed(filp);
1271 return 0;
1272 }
1273
1274 struct file_operations btrfs_file_operations = {
1275 .llseek = generic_file_llseek,
1276 .read = do_sync_read,
1277 .aio_read = generic_file_aio_read,
1278 .splice_read = generic_file_splice_read,
1279 .write = btrfs_file_write,
1280 .mmap = btrfs_file_mmap,
1281 .open = generic_file_open,
1282 .release = btrfs_release_file,
1283 .fsync = btrfs_sync_file,
1284 .unlocked_ioctl = btrfs_ioctl,
1285 #ifdef CONFIG_COMPAT
1286 .compat_ioctl = btrfs_ioctl,
1287 #endif
1288 };
Support for the Chinese Samsung S3C2440 based development boards