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Btrfs: remove #if 0 code
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / btrfs / file.c
blob1d51dc38bb497c3c068520d9d27eb487e1bce6e7
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 leaf_start;
295 u64 ram_bytes = 0;
296 u64 orig_parent = 0;
297 u64 disk_bytenr = 0;
298 u64 orig_locked_end = locked_end;
299 u8 compression;
300 u8 encryption;
301 u16 other_encoding = 0;
302 u64 root_gen;
303 u64 root_owner;
304 struct extent_buffer *leaf;
305 struct btrfs_file_extent_item *extent;
306 struct btrfs_path *path;
307 struct btrfs_key key;
308 struct btrfs_file_extent_item old;
309 int keep;
310 int slot;
311 int bookend;
312 int found_type = 0;
313 int found_extent;
314 int found_inline;
315 int recow;
316 int ret;
317
318 inline_limit = 0;
319 btrfs_drop_extent_cache(inode, start, end - 1, 0);
320
321 path = btrfs_alloc_path();
322 if (!path)
323 return -ENOMEM;
324 while (1) {
325 recow = 0;
326 btrfs_release_path(root, path);
327 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
328 search_start, -1);
329 if (ret < 0)
330 goto out;
331 if (ret > 0) {
332 if (path->slots[0] == 0) {
333 ret = 0;
334 goto out;
335 }
336 path->slots[0]--;
337 }
338 next_slot:
339 keep = 0;
340 bookend = 0;
341 found_extent = 0;
342 found_inline = 0;
343 leaf_start = 0;
344 root_gen = 0;
345 root_owner = 0;
346 compression = 0;
347 encryption = 0;
348 extent = NULL;
349 leaf = path->nodes[0];
350 slot = path->slots[0];
351 ret = 0;
352 btrfs_item_key_to_cpu(leaf, &key, slot);
353 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
354 key.offset >= end) {
355 goto out;
356 }
357 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
358 key.objectid != inode->i_ino) {
359 goto out;
360 }
361 if (recow) {
362 search_start = max(key.offset, start);
363 continue;
364 }
365 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
366 extent = btrfs_item_ptr(leaf, slot,
367 struct btrfs_file_extent_item);
368 found_type = btrfs_file_extent_type(leaf, extent);
369 compression = btrfs_file_extent_compression(leaf,
370 extent);
371 encryption = btrfs_file_extent_encryption(leaf,
372 extent);
373 other_encoding = btrfs_file_extent_other_encoding(leaf,
374 extent);
375 if (found_type == BTRFS_FILE_EXTENT_REG ||
376 found_type == BTRFS_FILE_EXTENT_PREALLOC) {
377 extent_end =
378 btrfs_file_extent_disk_bytenr(leaf,
379 extent);
380 if (extent_end)
381 *hint_byte = extent_end;
382
383 extent_end = key.offset +
384 btrfs_file_extent_num_bytes(leaf, extent);
385 ram_bytes = btrfs_file_extent_ram_bytes(leaf,
386 extent);
387 found_extent = 1;
388 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
389 found_inline = 1;
390 extent_end = key.offset +
391 btrfs_file_extent_inline_len(leaf, extent);
392 }
393 } else {
394 extent_end = search_start;
395 }
396
397 /* we found nothing we can drop */
398 if ((!found_extent && !found_inline) ||
399 search_start >= extent_end) {
400 int nextret;
401 u32 nritems;
402 nritems = btrfs_header_nritems(leaf);
403 if (slot >= nritems - 1) {
404 nextret = btrfs_next_leaf(root, path);
405 if (nextret)
406 goto out;
407 recow = 1;
408 } else {
409 path->slots[0]++;
410 }
411 goto next_slot;
412 }
413
414 if (end <= extent_end && start >= key.offset && found_inline)
415 *hint_byte = EXTENT_MAP_INLINE;
416
417 if (found_extent) {
418 read_extent_buffer(leaf, &old, (unsigned long)extent,
419 sizeof(old));
420 root_gen = btrfs_header_generation(leaf);
421 root_owner = btrfs_header_owner(leaf);
422 leaf_start = leaf->start;
423 }
424
425 if (end < extent_end && end >= key.offset) {
426 bookend = 1;
427 if (found_inline && start <= key.offset)
428 keep = 1;
429 }
430
431 if (bookend && found_extent) {
432 if (locked_end < extent_end) {
433 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
434 locked_end, extent_end - 1,
435 GFP_NOFS);
436 if (!ret) {
437 btrfs_release_path(root, path);
438 lock_extent(&BTRFS_I(inode)->io_tree,
439 locked_end, extent_end - 1,
440 GFP_NOFS);
441 locked_end = extent_end;
442 continue;
443 }
444 locked_end = extent_end;
445 }
446 orig_parent = path->nodes[0]->start;
447 disk_bytenr = le64_to_cpu(old.disk_bytenr);
448 if (disk_bytenr != 0) {
449 ret = btrfs_inc_extent_ref(trans, root,
450 disk_bytenr,
451 le64_to_cpu(old.disk_num_bytes),
452 orig_parent, root->root_key.objectid,
453 trans->transid, inode->i_ino);
454 BUG_ON(ret);
455 }
456 }
457
458 if (found_inline) {
459 u64 mask = root->sectorsize - 1;
460 search_start = (extent_end + mask) & ~mask;
461 } else
462 search_start = extent_end;
463
464 /* truncate existing extent */
465 if (start > key.offset) {
466 u64 new_num;
467 u64 old_num;
468 keep = 1;
469 WARN_ON(start & (root->sectorsize - 1));
470 if (found_extent) {
471 new_num = start - key.offset;
472 old_num = btrfs_file_extent_num_bytes(leaf,
473 extent);
474 *hint_byte =
475 btrfs_file_extent_disk_bytenr(leaf,
476 extent);
477 if (btrfs_file_extent_disk_bytenr(leaf,
478 extent)) {
479 inode_sub_bytes(inode, old_num -
480 new_num);
481 }
482 btrfs_set_file_extent_num_bytes(leaf,
483 extent, new_num);
484 btrfs_mark_buffer_dirty(leaf);
485 } else if (key.offset < inline_limit &&
486 (end > extent_end) &&
487 (inline_limit < extent_end)) {
488 u32 new_size;
489 new_size = btrfs_file_extent_calc_inline_size(
490 inline_limit - key.offset);
491 inode_sub_bytes(inode, extent_end -
492 inline_limit);
493 btrfs_set_file_extent_ram_bytes(leaf, extent,
494 new_size);
495 if (!compression && !encryption) {
496 btrfs_truncate_item(trans, root, path,
497 new_size, 1);
498 }
499 }
500 }
501 /* delete the entire extent */
502 if (!keep) {
503 if (found_inline)
504 inode_sub_bytes(inode, extent_end -
505 key.offset);
506 ret = btrfs_del_item(trans, root, path);
507 /* TODO update progress marker and return */
508 BUG_ON(ret);
509 extent = NULL;
510 btrfs_release_path(root, path);
511 /* the extent will be freed later */
512 }
513 if (bookend && found_inline && start <= key.offset) {
514 u32 new_size;
515 new_size = btrfs_file_extent_calc_inline_size(
516 extent_end - end);
517 inode_sub_bytes(inode, end - key.offset);
518 btrfs_set_file_extent_ram_bytes(leaf, extent,
519 new_size);
520 if (!compression && !encryption)
521 ret = btrfs_truncate_item(trans, root, path,
522 new_size, 0);
523 BUG_ON(ret);
524 }
525 /* create bookend, splitting the extent in two */
526 if (bookend && found_extent) {
527 struct btrfs_key ins;
528 ins.objectid = inode->i_ino;
529 ins.offset = end;
530 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
531
532 btrfs_release_path(root, path);
533 path->leave_spinning = 1;
534 ret = btrfs_insert_empty_item(trans, root, path, &ins,
535 sizeof(*extent));
536 BUG_ON(ret);
537
538 leaf = path->nodes[0];
539 extent = btrfs_item_ptr(leaf, path->slots[0],
540 struct btrfs_file_extent_item);
541 write_extent_buffer(leaf, &old,
542 (unsigned long)extent, sizeof(old));
543
544 btrfs_set_file_extent_compression(leaf, extent,
545 compression);
546 btrfs_set_file_extent_encryption(leaf, extent,
547 encryption);
548 btrfs_set_file_extent_other_encoding(leaf, extent,
549 other_encoding);
550 btrfs_set_file_extent_offset(leaf, extent,
551 le64_to_cpu(old.offset) + end - key.offset);
552 WARN_ON(le64_to_cpu(old.num_bytes) <
553 (extent_end - end));
554 btrfs_set_file_extent_num_bytes(leaf, extent,
555 extent_end - end);
556
557 /*
558 * set the ram bytes to the size of the full extent
559 * before splitting. This is a worst case flag,
560 * but its the best we can do because we don't know
561 * how splitting affects compression
562 */
563 btrfs_set_file_extent_ram_bytes(leaf, extent,
564 ram_bytes);
565 btrfs_set_file_extent_type(leaf, extent, found_type);
566
567 btrfs_unlock_up_safe(path, 1);
568 btrfs_mark_buffer_dirty(path->nodes[0]);
569 btrfs_set_lock_blocking(path->nodes[0]);
570
571 if (disk_bytenr != 0) {
572 ret = btrfs_update_extent_ref(trans, root,
573 disk_bytenr,
574 le64_to_cpu(old.disk_num_bytes),
575 orig_parent,
576 leaf->start,
577 root->root_key.objectid,
578 trans->transid, ins.objectid);
579
580 BUG_ON(ret);
581 }
582 path->leave_spinning = 0;
583 btrfs_release_path(root, path);
584 if (disk_bytenr != 0)
585 inode_add_bytes(inode, extent_end - end);
586 }
587
588 if (found_extent && !keep) {
589 u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr);
590
591 if (old_disk_bytenr != 0) {
592 inode_sub_bytes(inode,
593 le64_to_cpu(old.num_bytes));
594 ret = btrfs_free_extent(trans, root,
595 old_disk_bytenr,
596 le64_to_cpu(old.disk_num_bytes),
597 leaf_start, root_owner,
598 root_gen, key.objectid, 0);
599 BUG_ON(ret);
600 *hint_byte = old_disk_bytenr;
601 }
602 }
603
604 if (search_start >= end) {
605 ret = 0;
606 goto out;
607 }
608 }
609 out:
610 btrfs_free_path(path);
611 if (locked_end > orig_locked_end) {
612 unlock_extent(&BTRFS_I(inode)->io_tree, orig_locked_end,
613 locked_end - 1, GFP_NOFS);
614 }
615 return ret;
616 }
617
618 static int extent_mergeable(struct extent_buffer *leaf, int slot,
619 u64 objectid, u64 bytenr, u64 *start, u64 *end)
620 {
621 struct btrfs_file_extent_item *fi;
622 struct btrfs_key key;
623 u64 extent_end;
624
625 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
626 return 0;
627
628 btrfs_item_key_to_cpu(leaf, &key, slot);
629 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
630 return 0;
631
632 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
633 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
634 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
635 btrfs_file_extent_compression(leaf, fi) ||
636 btrfs_file_extent_encryption(leaf, fi) ||
637 btrfs_file_extent_other_encoding(leaf, fi))
638 return 0;
639
640 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
641 if ((*start && *start != key.offset) || (*end && *end != extent_end))
642 return 0;
643
644 *start = key.offset;
645 *end = extent_end;
646 return 1;
647 }
648
649 /*
650 * Mark extent in the range start - end as written.
651 *
652 * This changes extent type from 'pre-allocated' to 'regular'. If only
653 * part of extent is marked as written, the extent will be split into
654 * two or three.
655 */
656 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
657 struct btrfs_root *root,
658 struct inode *inode, u64 start, u64 end)
659 {
660 struct extent_buffer *leaf;
661 struct btrfs_path *path;
662 struct btrfs_file_extent_item *fi;
663 struct btrfs_key key;
664 u64 bytenr;
665 u64 num_bytes;
666 u64 extent_end;
667 u64 extent_offset;
668 u64 other_start;
669 u64 other_end;
670 u64 split = start;
671 u64 locked_end = end;
672 u64 orig_parent;
673 int extent_type;
674 int split_end = 1;
675 int ret;
676
677 btrfs_drop_extent_cache(inode, start, end - 1, 0);
678
679 path = btrfs_alloc_path();
680 BUG_ON(!path);
681 again:
682 key.objectid = inode->i_ino;
683 key.type = BTRFS_EXTENT_DATA_KEY;
684 if (split == start)
685 key.offset = split;
686 else
687 key.offset = split - 1;
688
689 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
690 if (ret > 0 && path->slots[0] > 0)
691 path->slots[0]--;
692
693 leaf = path->nodes[0];
694 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
695 BUG_ON(key.objectid != inode->i_ino ||
696 key.type != BTRFS_EXTENT_DATA_KEY);
697 fi = btrfs_item_ptr(leaf, path->slots[0],
698 struct btrfs_file_extent_item);
699 extent_type = btrfs_file_extent_type(leaf, fi);
700 BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC);
701 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
702 BUG_ON(key.offset > start || extent_end < end);
703
704 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
705 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
706 extent_offset = btrfs_file_extent_offset(leaf, fi);
707
708 if (key.offset == start)
709 split = end;
710
711 if (key.offset == start && extent_end == end) {
712 int del_nr = 0;
713 int del_slot = 0;
714 u64 leaf_owner = btrfs_header_owner(leaf);
715 u64 leaf_gen = btrfs_header_generation(leaf);
716 other_start = end;
717 other_end = 0;
718 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
719 bytenr, &other_start, &other_end)) {
720 extent_end = other_end;
721 del_slot = path->slots[0] + 1;
722 del_nr++;
723 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
724 leaf->start, leaf_owner,
725 leaf_gen, inode->i_ino, 0);
726 BUG_ON(ret);
727 }
728 other_start = 0;
729 other_end = start;
730 if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino,
731 bytenr, &other_start, &other_end)) {
732 key.offset = other_start;
733 del_slot = path->slots[0];
734 del_nr++;
735 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
736 leaf->start, leaf_owner,
737 leaf_gen, inode->i_ino, 0);
738 BUG_ON(ret);
739 }
740 split_end = 0;
741 if (del_nr == 0) {
742 btrfs_set_file_extent_type(leaf, fi,
743 BTRFS_FILE_EXTENT_REG);
744 goto done;
745 }
746
747 fi = btrfs_item_ptr(leaf, del_slot - 1,
748 struct btrfs_file_extent_item);
749 btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
750 btrfs_set_file_extent_num_bytes(leaf, fi,
751 extent_end - key.offset);
752 btrfs_mark_buffer_dirty(leaf);
753
754 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
755 BUG_ON(ret);
756 goto release;
757 } else if (split == start) {
758 if (locked_end < extent_end) {
759 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
760 locked_end, extent_end - 1, GFP_NOFS);
761 if (!ret) {
762 btrfs_release_path(root, path);
763 lock_extent(&BTRFS_I(inode)->io_tree,
764 locked_end, extent_end - 1, GFP_NOFS);
765 locked_end = extent_end;
766 goto again;
767 }
768 locked_end = extent_end;
769 }
770 btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
771 extent_offset += split - key.offset;
772 } else {
773 BUG_ON(key.offset != start);
774 btrfs_set_file_extent_offset(leaf, fi, extent_offset +
775 split - key.offset);
776 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
777 key.offset = split;
778 btrfs_set_item_key_safe(trans, root, path, &key);
779 extent_end = split;
780 }
781
782 if (extent_end == end) {
783 split_end = 0;
784 extent_type = BTRFS_FILE_EXTENT_REG;
785 }
786 if (extent_end == end && split == start) {
787 other_start = end;
788 other_end = 0;
789 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
790 bytenr, &other_start, &other_end)) {
791 path->slots[0]++;
792 fi = btrfs_item_ptr(leaf, path->slots[0],
793 struct btrfs_file_extent_item);
794 key.offset = split;
795 btrfs_set_item_key_safe(trans, root, path, &key);
796 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
797 btrfs_set_file_extent_num_bytes(leaf, fi,
798 other_end - split);
799 goto done;
800 }
801 }
802 if (extent_end == end && split == end) {
803 other_start = 0;
804 other_end = start;
805 if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino,
806 bytenr, &other_start, &other_end)) {
807 path->slots[0]--;
808 fi = btrfs_item_ptr(leaf, path->slots[0],
809 struct btrfs_file_extent_item);
810 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end -
811 other_start);
812 goto done;
813 }
814 }
815
816 btrfs_mark_buffer_dirty(leaf);
817
818 orig_parent = leaf->start;
819 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
820 orig_parent, root->root_key.objectid,
821 trans->transid, inode->i_ino);
822 BUG_ON(ret);
823 btrfs_release_path(root, path);
824
825 key.offset = start;
826 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi));
827 BUG_ON(ret);
828
829 leaf = path->nodes[0];
830 fi = btrfs_item_ptr(leaf, path->slots[0],
831 struct btrfs_file_extent_item);
832 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
833 btrfs_set_file_extent_type(leaf, fi, extent_type);
834 btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr);
835 btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
836 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
837 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset);
838 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
839 btrfs_set_file_extent_compression(leaf, fi, 0);
840 btrfs_set_file_extent_encryption(leaf, fi, 0);
841 btrfs_set_file_extent_other_encoding(leaf, fi, 0);
842
843 if (orig_parent != leaf->start) {
844 ret = btrfs_update_extent_ref(trans, root, bytenr, num_bytes,
845 orig_parent, leaf->start,
846 root->root_key.objectid,
847 trans->transid, inode->i_ino);
848 BUG_ON(ret);
849 }
850 done:
851 btrfs_mark_buffer_dirty(leaf);
852
853 release:
854 btrfs_release_path(root, path);
855 if (split_end && split == start) {
856 split = end;
857 goto again;
858 }
859 if (locked_end > end) {
860 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
861 GFP_NOFS);
862 }
863 btrfs_free_path(path);
864 return 0;
865 }
866
867 /*
868 * this gets pages into the page cache and locks them down, it also properly
869 * waits for data=ordered extents to finish before allowing the pages to be
870 * modified.
871 */
872 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
873 struct page **pages, size_t num_pages,
874 loff_t pos, unsigned long first_index,
875 unsigned long last_index, size_t write_bytes)
876 {
877 int i;
878 unsigned long index = pos >> PAGE_CACHE_SHIFT;
879 struct inode *inode = fdentry(file)->d_inode;
880 int err = 0;
881 u64 start_pos;
882 u64 last_pos;
883
884 start_pos = pos & ~((u64)root->sectorsize - 1);
885 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
886
887 if (start_pos > inode->i_size) {
888 err = btrfs_cont_expand(inode, start_pos);
889 if (err)
890 return err;
891 }
892
893 memset(pages, 0, num_pages * sizeof(struct page *));
894 again:
895 for (i = 0; i < num_pages; i++) {
896 pages[i] = grab_cache_page(inode->i_mapping, index + i);
897 if (!pages[i]) {
898 err = -ENOMEM;
899 BUG_ON(1);
900 }
901 wait_on_page_writeback(pages[i]);
902 }
903 if (start_pos < inode->i_size) {
904 struct btrfs_ordered_extent *ordered;
905 lock_extent(&BTRFS_I(inode)->io_tree,
906 start_pos, last_pos - 1, GFP_NOFS);
907 ordered = btrfs_lookup_first_ordered_extent(inode,
908 last_pos - 1);
909 if (ordered &&
910 ordered->file_offset + ordered->len > start_pos &&
911 ordered->file_offset < last_pos) {
912 btrfs_put_ordered_extent(ordered);
913 unlock_extent(&BTRFS_I(inode)->io_tree,
914 start_pos, last_pos - 1, GFP_NOFS);
915 for (i = 0; i < num_pages; i++) {
916 unlock_page(pages[i]);
917 page_cache_release(pages[i]);
918 }
919 btrfs_wait_ordered_range(inode, start_pos,
920 last_pos - start_pos);
921 goto again;
922 }
923 if (ordered)
924 btrfs_put_ordered_extent(ordered);
925
926 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
927 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
928 GFP_NOFS);
929 unlock_extent(&BTRFS_I(inode)->io_tree,
930 start_pos, last_pos - 1, GFP_NOFS);
931 }
932 for (i = 0; i < num_pages; i++) {
933 clear_page_dirty_for_io(pages[i]);
934 set_page_extent_mapped(pages[i]);
935 WARN_ON(!PageLocked(pages[i]));
936 }
937 return 0;
938 }
939
940 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
941 size_t count, loff_t *ppos)
942 {
943 loff_t pos;
944 loff_t start_pos;
945 ssize_t num_written = 0;
946 ssize_t err = 0;
947 int ret = 0;
948 struct inode *inode = fdentry(file)->d_inode;
949 struct btrfs_root *root = BTRFS_I(inode)->root;
950 struct page **pages = NULL;
951 int nrptrs;
952 struct page *pinned[2];
953 unsigned long first_index;
954 unsigned long last_index;
955 int will_write;
956
957 will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) ||
958 (file->f_flags & O_DIRECT));
959
960 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
961 PAGE_CACHE_SIZE / (sizeof(struct page *)));
962 pinned[0] = NULL;
963 pinned[1] = NULL;
964
965 pos = *ppos;
966 start_pos = pos;
967
968 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
969 current->backing_dev_info = inode->i_mapping->backing_dev_info;
970 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
971 if (err)
972 goto out_nolock;
973 if (count == 0)
974 goto out_nolock;
975
976 err = file_remove_suid(file);
977 if (err)
978 goto out_nolock;
979 file_update_time(file);
980
981 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
982
983 mutex_lock(&inode->i_mutex);
984 BTRFS_I(inode)->sequence++;
985 first_index = pos >> PAGE_CACHE_SHIFT;
986 last_index = (pos + count) >> PAGE_CACHE_SHIFT;
987
988 /*
989 * there are lots of better ways to do this, but this code
990 * makes sure the first and last page in the file range are
991 * up to date and ready for cow
992 */
993 if ((pos & (PAGE_CACHE_SIZE - 1))) {
994 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
995 if (!PageUptodate(pinned[0])) {
996 ret = btrfs_readpage(NULL, pinned[0]);
997 BUG_ON(ret);
998 wait_on_page_locked(pinned[0]);
999 } else {
1000 unlock_page(pinned[0]);
1001 }
1002 }
1003 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
1004 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
1005 if (!PageUptodate(pinned[1])) {
1006 ret = btrfs_readpage(NULL, pinned[1]);
1007 BUG_ON(ret);
1008 wait_on_page_locked(pinned[1]);
1009 } else {
1010 unlock_page(pinned[1]);
1011 }
1012 }
1013
1014 while (count > 0) {
1015 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
1016 size_t write_bytes = min(count, nrptrs *
1017 (size_t)PAGE_CACHE_SIZE -
1018 offset);
1019 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
1020 PAGE_CACHE_SHIFT;
1021
1022 WARN_ON(num_pages > nrptrs);
1023 memset(pages, 0, sizeof(struct page *) * nrptrs);
1024
1025 ret = btrfs_check_data_free_space(root, inode, write_bytes);
1026 if (ret)
1027 goto out;
1028
1029 ret = prepare_pages(root, file, pages, num_pages,
1030 pos, first_index, last_index,
1031 write_bytes);
1032 if (ret) {
1033 btrfs_free_reserved_data_space(root, inode,
1034 write_bytes);
1035 goto out;
1036 }
1037
1038 ret = btrfs_copy_from_user(pos, num_pages,
1039 write_bytes, pages, buf);
1040 if (ret) {
1041 btrfs_free_reserved_data_space(root, inode,
1042 write_bytes);
1043 btrfs_drop_pages(pages, num_pages);
1044 goto out;
1045 }
1046
1047 ret = dirty_and_release_pages(NULL, root, file, pages,
1048 num_pages, pos, write_bytes);
1049 btrfs_drop_pages(pages, num_pages);
1050 if (ret) {
1051 btrfs_free_reserved_data_space(root, inode,
1052 write_bytes);
1053 goto out;
1054 }
1055
1056 if (will_write) {
1057 btrfs_fdatawrite_range(inode->i_mapping, pos,
1058 pos + write_bytes - 1,
1059 WB_SYNC_ALL);
1060 } else {
1061 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1062 num_pages);
1063 if (num_pages <
1064 (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1065 btrfs_btree_balance_dirty(root, 1);
1066 btrfs_throttle(root);
1067 }
1068
1069 buf += write_bytes;
1070 count -= write_bytes;
1071 pos += write_bytes;
1072 num_written += write_bytes;
1073
1074 cond_resched();
1075 }
1076 out:
1077 mutex_unlock(&inode->i_mutex);
1078 if (ret)
1079 err = ret;
1080
1081 out_nolock:
1082 kfree(pages);
1083 if (pinned[0])
1084 page_cache_release(pinned[0]);
1085 if (pinned[1])
1086 page_cache_release(pinned[1]);
1087 *ppos = pos;
1088
1089 /*
1090 * we want to make sure fsync finds this change
1091 * but we haven't joined a transaction running right now.
1092 *
1093 * Later on, someone is sure to update the inode and get the
1094 * real transid recorded.
1095 *
1096 * We set last_trans now to the fs_info generation + 1,
1097 * this will either be one more than the running transaction
1098 * or the generation used for the next transaction if there isn't
1099 * one running right now.
1100 */
1101 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1102
1103 if (num_written > 0 && will_write) {
1104 struct btrfs_trans_handle *trans;
1105
1106 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1107 if (err)
1108 num_written = err;
1109
1110 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
1111 trans = btrfs_start_transaction(root, 1);
1112 ret = btrfs_log_dentry_safe(trans, root,
1113 file->f_dentry);
1114 if (ret == 0) {
1115 ret = btrfs_sync_log(trans, root);
1116 if (ret == 0)
1117 btrfs_end_transaction(trans, root);
1118 else
1119 btrfs_commit_transaction(trans, root);
1120 } else {
1121 btrfs_commit_transaction(trans, root);
1122 }
1123 }
1124 if (file->f_flags & O_DIRECT) {
1125 invalidate_mapping_pages(inode->i_mapping,
1126 start_pos >> PAGE_CACHE_SHIFT,
1127 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1128 }
1129 }
1130 current->backing_dev_info = NULL;
1131 return num_written ? num_written : err;
1132 }
1133
1134 int btrfs_release_file(struct inode *inode, struct file *filp)
1135 {
1136 /*
1137 * ordered_data_close is set by settattr when we are about to truncate
1138 * a file from a non-zero size to a zero size. This tries to
1139 * flush down new bytes that may have been written if the
1140 * application were using truncate to replace a file in place.
1141 */
1142 if (BTRFS_I(inode)->ordered_data_close) {
1143 BTRFS_I(inode)->ordered_data_close = 0;
1144 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1145 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1146 filemap_flush(inode->i_mapping);
1147 }
1148 if (filp->private_data)
1149 btrfs_ioctl_trans_end(filp);
1150 return 0;
1151 }
1152
1153 /*
1154 * fsync call for both files and directories. This logs the inode into
1155 * the tree log instead of forcing full commits whenever possible.
1156 *
1157 * It needs to call filemap_fdatawait so that all ordered extent updates are
1158 * in the metadata btree are up to date for copying to the log.
1159 *
1160 * It drops the inode mutex before doing the tree log commit. This is an
1161 * important optimization for directories because holding the mutex prevents
1162 * new operations on the dir while we write to disk.
1163 */
1164 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
1165 {
1166 struct inode *inode = dentry->d_inode;
1167 struct btrfs_root *root = BTRFS_I(inode)->root;
1168 int ret = 0;
1169 struct btrfs_trans_handle *trans;
1170
1171 /*
1172 * check the transaction that last modified this inode
1173 * and see if its already been committed
1174 */
1175 if (!BTRFS_I(inode)->last_trans)
1176 goto out;
1177
1178 mutex_lock(&root->fs_info->trans_mutex);
1179 if (BTRFS_I(inode)->last_trans <=
1180 root->fs_info->last_trans_committed) {
1181 BTRFS_I(inode)->last_trans = 0;
1182 mutex_unlock(&root->fs_info->trans_mutex);
1183 goto out;
1184 }
1185 mutex_unlock(&root->fs_info->trans_mutex);
1186
1187 root->log_batch++;
1188 filemap_fdatawrite(inode->i_mapping);
1189 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1190 root->log_batch++;
1191
1192 /*
1193 * ok we haven't committed the transaction yet, lets do a commit
1194 */
1195 if (file && file->private_data)
1196 btrfs_ioctl_trans_end(file);
1197
1198 trans = btrfs_start_transaction(root, 1);
1199 if (!trans) {
1200 ret = -ENOMEM;
1201 goto out;
1202 }
1203
1204 ret = btrfs_log_dentry_safe(trans, root, dentry);
1205 if (ret < 0)
1206 goto out;
1207
1208 /* we've logged all the items and now have a consistent
1209 * version of the file in the log. It is possible that
1210 * someone will come in and modify the file, but that's
1211 * fine because the log is consistent on disk, and we
1212 * have references to all of the file's extents
1213 *
1214 * It is possible that someone will come in and log the
1215 * file again, but that will end up using the synchronization
1216 * inside btrfs_sync_log to keep things safe.
1217 */
1218 mutex_unlock(&dentry->d_inode->i_mutex);
1219
1220 if (ret > 0) {
1221 ret = btrfs_commit_transaction(trans, root);
1222 } else {
1223 ret = btrfs_sync_log(trans, root);
1224 if (ret == 0)
1225 ret = btrfs_end_transaction(trans, root);
1226 else
1227 ret = btrfs_commit_transaction(trans, root);
1228 }
1229 mutex_lock(&dentry->d_inode->i_mutex);
1230 out:
1231 return ret > 0 ? EIO : ret;
1232 }
1233
1234 static struct vm_operations_struct btrfs_file_vm_ops = {
1235 .fault = filemap_fault,
1236 .page_mkwrite = btrfs_page_mkwrite,
1237 };
1238
1239 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1240 {
1241 vma->vm_ops = &btrfs_file_vm_ops;
1242 file_accessed(filp);
1243 return 0;
1244 }
1245
1246 struct file_operations btrfs_file_operations = {
1247 .llseek = generic_file_llseek,
1248 .read = do_sync_read,
1249 .aio_read = generic_file_aio_read,
1250 .splice_read = generic_file_splice_read,
1251 .write = btrfs_file_write,
1252 .mmap = btrfs_file_mmap,
1253 .open = generic_file_open,
1254 .release = btrfs_release_file,
1255 .fsync = btrfs_sync_file,
1256 .unlocked_ioctl = btrfs_ioctl,
1257 #ifdef CONFIG_COMPAT
1258 .compat_ioctl = btrfs_ioctl,
1259 #endif
1260 };
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree