?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Btrfs: O_DIRECT writes via buffered writes + invaldiate
[linux-2.6/btrfs-unstable.git] / fs / btrfs / file.c
bloba03d1bbb19adf393a99310922bb9cf60ffd5827e
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 int noinline 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 void noinline 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 /* this does all the hard work for inserting an inline extent into
99 * the btree. Any existing inline extent is extended as required to make room,
100 * otherwise things are inserted as required into the btree
101 */
102 static int noinline insert_inline_extent(struct btrfs_trans_handle *trans,
103 struct btrfs_root *root, struct inode *inode,
104 u64 offset, size_t size,
105 struct page **pages, size_t page_offset,
106 int num_pages)
107 {
108 struct btrfs_key key;
109 struct btrfs_path *path;
110 struct extent_buffer *leaf;
111 char *kaddr;
112 unsigned long ptr;
113 struct btrfs_file_extent_item *ei;
114 struct page *page;
115 u32 datasize;
116 int err = 0;
117 int ret;
118 int i;
119 ssize_t cur_size;
120
121 path = btrfs_alloc_path();
122 if (!path)
123 return -ENOMEM;
124
125 btrfs_set_trans_block_group(trans, inode);
126
127 key.objectid = inode->i_ino;
128 key.offset = offset;
129 btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
130
131 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
132 if (ret < 0) {
133 err = ret;
134 goto fail;
135 }
136 if (ret == 1) {
137 struct btrfs_key found_key;
138
139 if (path->slots[0] == 0)
140 goto insert;
141
142 path->slots[0]--;
143 leaf = path->nodes[0];
144 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
145
146 if (found_key.objectid != inode->i_ino)
147 goto insert;
148
149 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
150 goto insert;
151 ei = btrfs_item_ptr(leaf, path->slots[0],
152 struct btrfs_file_extent_item);
153
154 if (btrfs_file_extent_type(leaf, ei) !=
155 BTRFS_FILE_EXTENT_INLINE) {
156 goto insert;
157 }
158 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
159 ret = 0;
160 }
161 if (ret == 0) {
162 u32 found_size;
163 u64 found_end;
164
165 leaf = path->nodes[0];
166 ei = btrfs_item_ptr(leaf, path->slots[0],
167 struct btrfs_file_extent_item);
168
169 if (btrfs_file_extent_type(leaf, ei) !=
170 BTRFS_FILE_EXTENT_INLINE) {
171 err = ret;
172 btrfs_print_leaf(root, leaf);
173 printk("found wasn't inline offset %Lu inode %lu\n",
174 offset, inode->i_ino);
175 goto fail;
176 }
177 found_size = btrfs_file_extent_inline_len(leaf,
178 btrfs_item_nr(leaf, path->slots[0]));
179 found_end = key.offset + found_size;
180
181 if (found_end < offset + size) {
182 btrfs_release_path(root, path);
183 ret = btrfs_search_slot(trans, root, &key, path,
184 offset + size - found_end, 1);
185 BUG_ON(ret != 0);
186
187 ret = btrfs_extend_item(trans, root, path,
188 offset + size - found_end);
189 if (ret) {
190 err = ret;
191 goto fail;
192 }
193 leaf = path->nodes[0];
194 ei = btrfs_item_ptr(leaf, path->slots[0],
195 struct btrfs_file_extent_item);
196 inode->i_blocks += (offset + size - found_end) >> 9;
197 }
198 if (found_end < offset) {
199 ptr = btrfs_file_extent_inline_start(ei) + found_size;
200 memset_extent_buffer(leaf, 0, ptr, offset - found_end);
201 }
202 } else {
203 insert:
204 btrfs_release_path(root, path);
205 datasize = offset + size - key.offset;
206 inode->i_blocks += datasize >> 9;
207 datasize = btrfs_file_extent_calc_inline_size(datasize);
208 ret = btrfs_insert_empty_item(trans, root, path, &key,
209 datasize);
210 if (ret) {
211 err = ret;
212 printk("got bad ret %d\n", ret);
213 goto fail;
214 }
215 leaf = path->nodes[0];
216 ei = btrfs_item_ptr(leaf, path->slots[0],
217 struct btrfs_file_extent_item);
218 btrfs_set_file_extent_generation(leaf, ei, trans->transid);
219 btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
220 }
221 ptr = btrfs_file_extent_inline_start(ei) + offset - key.offset;
222
223 cur_size = size;
224 i = 0;
225 while (size > 0) {
226 page = pages[i];
227 kaddr = kmap_atomic(page, KM_USER0);
228 cur_size = min_t(size_t, PAGE_CACHE_SIZE - page_offset, size);
229 write_extent_buffer(leaf, kaddr + page_offset, ptr, cur_size);
230 kunmap_atomic(kaddr, KM_USER0);
231 page_offset = 0;
232 ptr += cur_size;
233 size -= cur_size;
234 if (i >= num_pages) {
235 printk("i %d num_pages %d\n", i, num_pages);
236 }
237 i++;
238 }
239 btrfs_mark_buffer_dirty(leaf);
240 fail:
241 btrfs_free_path(path);
242 return err;
243 }
244
245 /*
246 * after copy_from_user, pages need to be dirtied and we need to make
247 * sure holes are created between the current EOF and the start of
248 * any next extents (if required).
249 *
250 * this also makes the decision about creating an inline extent vs
251 * doing real data extents, marking pages dirty and delalloc as required.
252 */
253 static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
254 struct btrfs_root *root,
255 struct file *file,
256 struct page **pages,
257 size_t num_pages,
258 loff_t pos,
259 size_t write_bytes)
260 {
261 int err = 0;
262 int i;
263 struct inode *inode = fdentry(file)->d_inode;
264 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
265 u64 hint_byte;
266 u64 num_bytes;
267 u64 start_pos;
268 u64 end_of_last_block;
269 u64 end_pos = pos + write_bytes;
270 u64 inline_size;
271 int did_inline = 0;
272 loff_t isize = i_size_read(inode);
273
274 start_pos = pos & ~((u64)root->sectorsize - 1);
275 num_bytes = (write_bytes + pos - start_pos +
276 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
277
278 end_of_last_block = start_pos + num_bytes - 1;
279
280 lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
281 trans = btrfs_join_transaction(root, 1);
282 if (!trans) {
283 err = -ENOMEM;
284 goto out_unlock;
285 }
286 btrfs_set_trans_block_group(trans, inode);
287 hint_byte = 0;
288
289 if ((end_of_last_block & 4095) == 0) {
290 printk("strange end of last %Lu %zu %Lu\n", start_pos, write_bytes, end_of_last_block);
291 }
292 set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
293
294 /* FIXME...EIEIO, ENOSPC and more */
295 /* insert any holes we need to create */
296 if (isize < start_pos) {
297 u64 last_pos_in_file;
298 u64 hole_size;
299 u64 mask = root->sectorsize - 1;
300 last_pos_in_file = (isize + mask) & ~mask;
301 hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
302 if (hole_size > 0) {
303 btrfs_wait_ordered_range(inode, last_pos_in_file,
304 last_pos_in_file + hole_size);
305 mutex_lock(&BTRFS_I(inode)->extent_mutex);
306 err = btrfs_drop_extents(trans, root, inode,
307 last_pos_in_file,
308 last_pos_in_file + hole_size,
309 last_pos_in_file,
310 &hint_byte);
311 if (err)
312 goto failed;
313
314 err = btrfs_insert_file_extent(trans, root,
315 inode->i_ino,
316 last_pos_in_file,
317 0, 0, hole_size, 0);
318 btrfs_drop_extent_cache(inode, last_pos_in_file,
319 last_pos_in_file + hole_size - 1, 0);
320 mutex_unlock(&BTRFS_I(inode)->extent_mutex);
321 btrfs_check_file(root, inode);
322 }
323 if (err)
324 goto failed;
325 }
326
327 /*
328 * either allocate an extent for the new bytes or setup the key
329 * to show we are doing inline data in the extent
330 */
331 inline_size = end_pos;
332 if (isize >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
333 inline_size > root->fs_info->max_inline ||
334 (inline_size & (root->sectorsize -1)) == 0 ||
335 inline_size >= BTRFS_MAX_INLINE_DATA_SIZE(root)) {
336 /* check for reserved extents on each page, we don't want
337 * to reset the delalloc bit on things that already have
338 * extents reserved.
339 */
340 btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
341 for (i = 0; i < num_pages; i++) {
342 struct page *p = pages[i];
343 SetPageUptodate(p);
344 ClearPageChecked(p);
345 set_page_dirty(p);
346 }
347 } else {
348 u64 aligned_end;
349 /* step one, delete the existing extents in this range */
350 aligned_end = (pos + write_bytes + root->sectorsize - 1) &
351 ~((u64)root->sectorsize - 1);
352 mutex_lock(&BTRFS_I(inode)->extent_mutex);
353 err = btrfs_drop_extents(trans, root, inode, start_pos,
354 aligned_end, aligned_end, &hint_byte);
355 if (err)
356 goto failed;
357 if (isize > inline_size)
358 inline_size = min_t(u64, isize, aligned_end);
359 inline_size -= start_pos;
360 err = insert_inline_extent(trans, root, inode, start_pos,
361 inline_size, pages, 0, num_pages);
362 btrfs_drop_extent_cache(inode, start_pos, aligned_end - 1, 0);
363 BUG_ON(err);
364 mutex_unlock(&BTRFS_I(inode)->extent_mutex);
365
366 /*
367 * an ugly way to do all the prop accounting around
368 * the page bits and mapping tags
369 */
370 set_page_writeback(pages[0]);
371 end_page_writeback(pages[0]);
372 did_inline = 1;
373 }
374 if (end_pos > isize) {
375 i_size_write(inode, end_pos);
376 if (did_inline)
377 BTRFS_I(inode)->disk_i_size = end_pos;
378 btrfs_update_inode(trans, root, inode);
379 }
380 failed:
381 err = btrfs_end_transaction(trans, root);
382 out_unlock:
383 unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
384 return err;
385 }
386
387 /*
388 * this drops all the extents in the cache that intersect the range
389 * [start, end]. Existing extents are split as required.
390 */
391 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
392 int skip_pinned)
393 {
394 struct extent_map *em;
395 struct extent_map *split = NULL;
396 struct extent_map *split2 = NULL;
397 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
398 u64 len = end - start + 1;
399 int ret;
400 int testend = 1;
401 unsigned long flags;
402
403 WARN_ON(end < start);
404 if (end == (u64)-1) {
405 len = (u64)-1;
406 testend = 0;
407 }
408 while(1) {
409 if (!split)
410 split = alloc_extent_map(GFP_NOFS);
411 if (!split2)
412 split2 = alloc_extent_map(GFP_NOFS);
413
414 spin_lock(&em_tree->lock);
415 em = lookup_extent_mapping(em_tree, start, len);
416 if (!em) {
417 spin_unlock(&em_tree->lock);
418 break;
419 }
420 flags = em->flags;
421 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
422 spin_unlock(&em_tree->lock);
423 if (em->start <= start &&
424 (!testend || em->start + em->len >= start + len)) {
425 free_extent_map(em);
426 break;
427 }
428 if (start < em->start) {
429 len = em->start - start;
430 } else {
431 len = start + len - (em->start + em->len);
432 start = em->start + em->len;
433 }
434 free_extent_map(em);
435 continue;
436 }
437 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
438 remove_extent_mapping(em_tree, em);
439
440 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
441 em->start < start) {
442 split->start = em->start;
443 split->len = start - em->start;
444 split->block_start = em->block_start;
445 split->bdev = em->bdev;
446 split->flags = flags;
447 ret = add_extent_mapping(em_tree, split);
448 BUG_ON(ret);
449 free_extent_map(split);
450 split = split2;
451 split2 = NULL;
452 }
453 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
454 testend && em->start + em->len > start + len) {
455 u64 diff = start + len - em->start;
456
457 split->start = start + len;
458 split->len = em->start + em->len - (start + len);
459 split->bdev = em->bdev;
460 split->flags = flags;
461
462 split->block_start = em->block_start + diff;
463
464 ret = add_extent_mapping(em_tree, split);
465 BUG_ON(ret);
466 free_extent_map(split);
467 split = NULL;
468 }
469 spin_unlock(&em_tree->lock);
470
471 /* once for us */
472 free_extent_map(em);
473 /* once for the tree*/
474 free_extent_map(em);
475 }
476 if (split)
477 free_extent_map(split);
478 if (split2)
479 free_extent_map(split2);
480 return 0;
481 }
482
483 int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
484 {
485 return 0;
486 #if 0
487 struct btrfs_path *path;
488 struct btrfs_key found_key;
489 struct extent_buffer *leaf;
490 struct btrfs_file_extent_item *extent;
491 u64 last_offset = 0;
492 int nritems;
493 int slot;
494 int found_type;
495 int ret;
496 int err = 0;
497 u64 extent_end = 0;
498
499 path = btrfs_alloc_path();
500 ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
501 last_offset, 0);
502 while(1) {
503 nritems = btrfs_header_nritems(path->nodes[0]);
504 if (path->slots[0] >= nritems) {
505 ret = btrfs_next_leaf(root, path);
506 if (ret)
507 goto out;
508 nritems = btrfs_header_nritems(path->nodes[0]);
509 }
510 slot = path->slots[0];
511 leaf = path->nodes[0];
512 btrfs_item_key_to_cpu(leaf, &found_key, slot);
513 if (found_key.objectid != inode->i_ino)
514 break;
515 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
516 goto out;
517
518 if (found_key.offset < last_offset) {
519 WARN_ON(1);
520 btrfs_print_leaf(root, leaf);
521 printk("inode %lu found offset %Lu expected %Lu\n",
522 inode->i_ino, found_key.offset, last_offset);
523 err = 1;
524 goto out;
525 }
526 extent = btrfs_item_ptr(leaf, slot,
527 struct btrfs_file_extent_item);
528 found_type = btrfs_file_extent_type(leaf, extent);
529 if (found_type == BTRFS_FILE_EXTENT_REG) {
530 extent_end = found_key.offset +
531 btrfs_file_extent_num_bytes(leaf, extent);
532 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
533 struct btrfs_item *item;
534 item = btrfs_item_nr(leaf, slot);
535 extent_end = found_key.offset +
536 btrfs_file_extent_inline_len(leaf, item);
537 extent_end = (extent_end + root->sectorsize - 1) &
538 ~((u64)root->sectorsize -1 );
539 }
540 last_offset = extent_end;
541 path->slots[0]++;
542 }
543 if (0 && last_offset < inode->i_size) {
544 WARN_ON(1);
545 btrfs_print_leaf(root, leaf);
546 printk("inode %lu found offset %Lu size %Lu\n", inode->i_ino,
547 last_offset, inode->i_size);
548 err = 1;
549
550 }
551 out:
552 btrfs_free_path(path);
553 return err;
554 #endif
555 }
556
557 /*
558 * this is very complex, but the basic idea is to drop all extents
559 * in the range start - end. hint_block is filled in with a block number
560 * that would be a good hint to the block allocator for this file.
561 *
562 * If an extent intersects the range but is not entirely inside the range
563 * it is either truncated or split. Anything entirely inside the range
564 * is deleted from the tree.
565 *
566 * inline_limit is used to tell this code which offsets in the file to keep
567 * if they contain inline extents.
568 */
569 int noinline btrfs_drop_extents(struct btrfs_trans_handle *trans,
570 struct btrfs_root *root, struct inode *inode,
571 u64 start, u64 end, u64 inline_limit, u64 *hint_byte)
572 {
573 u64 extent_end = 0;
574 u64 search_start = start;
575 u64 leaf_start;
576 u64 root_gen;
577 u64 root_owner;
578 struct extent_buffer *leaf;
579 struct btrfs_file_extent_item *extent;
580 struct btrfs_path *path;
581 struct btrfs_key key;
582 struct btrfs_file_extent_item old;
583 int keep;
584 int slot;
585 int bookend;
586 int found_type;
587 int found_extent;
588 int found_inline;
589 int recow;
590 int ret;
591
592 btrfs_drop_extent_cache(inode, start, end - 1, 0);
593
594 path = btrfs_alloc_path();
595 if (!path)
596 return -ENOMEM;
597 while(1) {
598 recow = 0;
599 btrfs_release_path(root, path);
600 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
601 search_start, -1);
602 if (ret < 0)
603 goto out;
604 if (ret > 0) {
605 if (path->slots[0] == 0) {
606 ret = 0;
607 goto out;
608 }
609 path->slots[0]--;
610 }
611 next_slot:
612 keep = 0;
613 bookend = 0;
614 found_extent = 0;
615 found_inline = 0;
616 leaf_start = 0;
617 root_gen = 0;
618 root_owner = 0;
619 extent = NULL;
620 leaf = path->nodes[0];
621 slot = path->slots[0];
622 ret = 0;
623 btrfs_item_key_to_cpu(leaf, &key, slot);
624 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
625 key.offset >= end) {
626 goto out;
627 }
628 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
629 key.objectid != inode->i_ino) {
630 goto out;
631 }
632 if (recow) {
633 search_start = key.offset;
634 continue;
635 }
636 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
637 extent = btrfs_item_ptr(leaf, slot,
638 struct btrfs_file_extent_item);
639 found_type = btrfs_file_extent_type(leaf, extent);
640 if (found_type == BTRFS_FILE_EXTENT_REG) {
641 extent_end =
642 btrfs_file_extent_disk_bytenr(leaf,
643 extent);
644 if (extent_end)
645 *hint_byte = extent_end;
646
647 extent_end = key.offset +
648 btrfs_file_extent_num_bytes(leaf, extent);
649 found_extent = 1;
650 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
651 struct btrfs_item *item;
652 item = btrfs_item_nr(leaf, slot);
653 found_inline = 1;
654 extent_end = key.offset +
655 btrfs_file_extent_inline_len(leaf, item);
656 }
657 } else {
658 extent_end = search_start;
659 }
660
661 /* we found nothing we can drop */
662 if ((!found_extent && !found_inline) ||
663 search_start >= extent_end) {
664 int nextret;
665 u32 nritems;
666 nritems = btrfs_header_nritems(leaf);
667 if (slot >= nritems - 1) {
668 nextret = btrfs_next_leaf(root, path);
669 if (nextret)
670 goto out;
671 recow = 1;
672 } else {
673 path->slots[0]++;
674 }
675 goto next_slot;
676 }
677
678 if (found_inline) {
679 u64 mask = root->sectorsize - 1;
680 search_start = (extent_end + mask) & ~mask;
681 } else
682 search_start = extent_end;
683 if (end <= extent_end && start >= key.offset && found_inline) {
684 *hint_byte = EXTENT_MAP_INLINE;
685 goto out;
686 }
687
688 if (found_extent) {
689 read_extent_buffer(leaf, &old, (unsigned long)extent,
690 sizeof(old));
691 root_gen = btrfs_header_generation(leaf);
692 root_owner = btrfs_header_owner(leaf);
693 leaf_start = leaf->start;
694 }
695
696 if (end < extent_end && end >= key.offset) {
697 bookend = 1;
698 if (found_inline && start <= key.offset)
699 keep = 1;
700 }
701 /* truncate existing extent */
702 if (start > key.offset) {
703 u64 new_num;
704 u64 old_num;
705 keep = 1;
706 WARN_ON(start & (root->sectorsize - 1));
707 if (found_extent) {
708 new_num = start - key.offset;
709 old_num = btrfs_file_extent_num_bytes(leaf,
710 extent);
711 *hint_byte =
712 btrfs_file_extent_disk_bytenr(leaf,
713 extent);
714 if (btrfs_file_extent_disk_bytenr(leaf,
715 extent)) {
716 dec_i_blocks(inode, old_num - new_num);
717 }
718 btrfs_set_file_extent_num_bytes(leaf, extent,
719 new_num);
720 btrfs_mark_buffer_dirty(leaf);
721 } else if (key.offset < inline_limit &&
722 (end > extent_end) &&
723 (inline_limit < extent_end)) {
724 u32 new_size;
725 new_size = btrfs_file_extent_calc_inline_size(
726 inline_limit - key.offset);
727 dec_i_blocks(inode, (extent_end - key.offset) -
728 (inline_limit - key.offset));
729 btrfs_truncate_item(trans, root, path,
730 new_size, 1);
731 }
732 }
733 /* delete the entire extent */
734 if (!keep) {
735 ret = btrfs_del_item(trans, root, path);
736 /* TODO update progress marker and return */
737 BUG_ON(ret);
738 extent = NULL;
739 btrfs_release_path(root, path);
740 /* the extent will be freed later */
741 }
742 if (bookend && found_inline && start <= key.offset) {
743 u32 new_size;
744 new_size = btrfs_file_extent_calc_inline_size(
745 extent_end - end);
746 dec_i_blocks(inode, (extent_end - key.offset) -
747 (extent_end - end));
748 ret = btrfs_truncate_item(trans, root, path,
749 new_size, 0);
750 BUG_ON(ret);
751 }
752 /* create bookend, splitting the extent in two */
753 if (bookend && found_extent) {
754 u64 disk_bytenr;
755 struct btrfs_key ins;
756 ins.objectid = inode->i_ino;
757 ins.offset = end;
758 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
759 btrfs_release_path(root, path);
760 ret = btrfs_insert_empty_item(trans, root, path, &ins,
761 sizeof(*extent));
762 BUG_ON(ret);
763
764 leaf = path->nodes[0];
765 extent = btrfs_item_ptr(leaf, path->slots[0],
766 struct btrfs_file_extent_item);
767 write_extent_buffer(leaf, &old,
768 (unsigned long)extent, sizeof(old));
769
770 btrfs_set_file_extent_offset(leaf, extent,
771 le64_to_cpu(old.offset) + end - key.offset);
772 WARN_ON(le64_to_cpu(old.num_bytes) <
773 (extent_end - end));
774 btrfs_set_file_extent_num_bytes(leaf, extent,
775 extent_end - end);
776 btrfs_set_file_extent_type(leaf, extent,
777 BTRFS_FILE_EXTENT_REG);
778
779 btrfs_mark_buffer_dirty(path->nodes[0]);
780
781 disk_bytenr = le64_to_cpu(old.disk_bytenr);
782 if (disk_bytenr != 0) {
783 ret = btrfs_inc_extent_ref(trans, root,
784 disk_bytenr,
785 le64_to_cpu(old.disk_num_bytes),
786 leaf->start,
787 root->root_key.objectid,
788 trans->transid,
789 ins.objectid, ins.offset);
790 BUG_ON(ret);
791 }
792 btrfs_release_path(root, path);
793 if (disk_bytenr != 0) {
794 inode->i_blocks +=
795 btrfs_file_extent_num_bytes(leaf,
796 extent) >> 9;
797 }
798 }
799
800 if (found_extent && !keep) {
801 u64 disk_bytenr = le64_to_cpu(old.disk_bytenr);
802
803 if (disk_bytenr != 0) {
804 dec_i_blocks(inode, le64_to_cpu(old.num_bytes));
805 ret = btrfs_free_extent(trans, root,
806 disk_bytenr,
807 le64_to_cpu(old.disk_num_bytes),
808 leaf_start, root_owner,
809 root_gen, key.objectid,
810 key.offset, 0);
811 BUG_ON(ret);
812 *hint_byte = disk_bytenr;
813 }
814 }
815
816 if (search_start >= end) {
817 ret = 0;
818 goto out;
819 }
820 }
821 out:
822 btrfs_free_path(path);
823 btrfs_check_file(root, inode);
824 return ret;
825 }
826
827 /*
828 * this gets pages into the page cache and locks them down, it also properly
829 * waits for data=ordered extents to finish before allowing the pages to be
830 * modified.
831 */
832 static int noinline prepare_pages(struct btrfs_root *root, struct file *file,
833 struct page **pages, size_t num_pages,
834 loff_t pos, unsigned long first_index,
835 unsigned long last_index, size_t write_bytes)
836 {
837 int i;
838 unsigned long index = pos >> PAGE_CACHE_SHIFT;
839 struct inode *inode = fdentry(file)->d_inode;
840 int err = 0;
841 u64 start_pos;
842 u64 last_pos;
843
844 start_pos = pos & ~((u64)root->sectorsize - 1);
845 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
846
847 memset(pages, 0, num_pages * sizeof(struct page *));
848 again:
849 for (i = 0; i < num_pages; i++) {
850 pages[i] = grab_cache_page(inode->i_mapping, index + i);
851 if (!pages[i]) {
852 err = -ENOMEM;
853 BUG_ON(1);
854 }
855 wait_on_page_writeback(pages[i]);
856 }
857 if (start_pos < inode->i_size) {
858 struct btrfs_ordered_extent *ordered;
859 lock_extent(&BTRFS_I(inode)->io_tree,
860 start_pos, last_pos - 1, GFP_NOFS);
861 ordered = btrfs_lookup_first_ordered_extent(inode, last_pos -1);
862 if (ordered &&
863 ordered->file_offset + ordered->len > start_pos &&
864 ordered->file_offset < last_pos) {
865 btrfs_put_ordered_extent(ordered);
866 unlock_extent(&BTRFS_I(inode)->io_tree,
867 start_pos, last_pos - 1, GFP_NOFS);
868 for (i = 0; i < num_pages; i++) {
869 unlock_page(pages[i]);
870 page_cache_release(pages[i]);
871 }
872 btrfs_wait_ordered_range(inode, start_pos,
873 last_pos - start_pos);
874 goto again;
875 }
876 if (ordered)
877 btrfs_put_ordered_extent(ordered);
878
879 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
880 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
881 GFP_NOFS);
882 unlock_extent(&BTRFS_I(inode)->io_tree,
883 start_pos, last_pos - 1, GFP_NOFS);
884 }
885 for (i = 0; i < num_pages; i++) {
886 clear_page_dirty_for_io(pages[i]);
887 set_page_extent_mapped(pages[i]);
888 WARN_ON(!PageLocked(pages[i]));
889 }
890 return 0;
891 }
892
893 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
894 size_t count, loff_t *ppos)
895 {
896 loff_t pos;
897 loff_t start_pos;
898 ssize_t num_written = 0;
899 ssize_t err = 0;
900 int ret = 0;
901 struct inode *inode = fdentry(file)->d_inode;
902 struct btrfs_root *root = BTRFS_I(inode)->root;
903 struct page **pages = NULL;
904 int nrptrs;
905 struct page *pinned[2];
906 unsigned long first_index;
907 unsigned long last_index;
908 int will_write;
909
910 will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) ||
911 (file->f_flags & O_DIRECT));
912
913 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
914 PAGE_CACHE_SIZE / (sizeof(struct page *)));
915 pinned[0] = NULL;
916 pinned[1] = NULL;
917
918 pos = *ppos;
919 start_pos = pos;
920
921 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
922 current->backing_dev_info = inode->i_mapping->backing_dev_info;
923 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
924 if (err)
925 goto out_nolock;
926 if (count == 0)
927 goto out_nolock;
928
929 err = file_remove_suid(file);
930 if (err)
931 goto out_nolock;
932 file_update_time(file);
933
934 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
935
936 mutex_lock(&inode->i_mutex);
937 first_index = pos >> PAGE_CACHE_SHIFT;
938 last_index = (pos + count) >> PAGE_CACHE_SHIFT;
939
940 /*
941 * if this is a nodatasum mount, force summing off for the inode
942 * all the time. That way a later mount with summing on won't
943 * get confused
944 */
945 if (btrfs_test_opt(root, NODATASUM))
946 btrfs_set_flag(inode, NODATASUM);
947
948 /*
949 * there are lots of better ways to do this, but this code
950 * makes sure the first and last page in the file range are
951 * up to date and ready for cow
952 */
953 if ((pos & (PAGE_CACHE_SIZE - 1))) {
954 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
955 if (!PageUptodate(pinned[0])) {
956 ret = btrfs_readpage(NULL, pinned[0]);
957 BUG_ON(ret);
958 wait_on_page_locked(pinned[0]);
959 } else {
960 unlock_page(pinned[0]);
961 }
962 }
963 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
964 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
965 if (!PageUptodate(pinned[1])) {
966 ret = btrfs_readpage(NULL, pinned[1]);
967 BUG_ON(ret);
968 wait_on_page_locked(pinned[1]);
969 } else {
970 unlock_page(pinned[1]);
971 }
972 }
973
974 while(count > 0) {
975 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
976 size_t write_bytes = min(count, nrptrs *
977 (size_t)PAGE_CACHE_SIZE -
978 offset);
979 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
980 PAGE_CACHE_SHIFT;
981
982 WARN_ON(num_pages > nrptrs);
983 memset(pages, 0, sizeof(pages));
984
985 ret = btrfs_check_free_space(root, write_bytes, 0);
986 if (ret)
987 goto out;
988
989 ret = prepare_pages(root, file, pages, num_pages,
990 pos, first_index, last_index,
991 write_bytes);
992 if (ret)
993 goto out;
994
995 ret = btrfs_copy_from_user(pos, num_pages,
996 write_bytes, pages, buf);
997 if (ret) {
998 btrfs_drop_pages(pages, num_pages);
999 goto out;
1000 }
1001
1002 ret = dirty_and_release_pages(NULL, root, file, pages,
1003 num_pages, pos, write_bytes);
1004 btrfs_drop_pages(pages, num_pages);
1005 if (ret)
1006 goto out;
1007
1008 if (will_write) {
1009 btrfs_fdatawrite_range(inode->i_mapping, pos,
1010 pos + write_bytes - 1,
1011 WB_SYNC_NONE);
1012 } else {
1013 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1014 num_pages);
1015 if (num_pages <
1016 (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1017 btrfs_btree_balance_dirty(root, 1);
1018 btrfs_throttle(root);
1019 }
1020
1021 buf += write_bytes;
1022 count -= write_bytes;
1023 pos += write_bytes;
1024 num_written += write_bytes;
1025
1026 cond_resched();
1027 }
1028 out:
1029 mutex_unlock(&inode->i_mutex);
1030
1031 out_nolock:
1032 kfree(pages);
1033 if (pinned[0])
1034 page_cache_release(pinned[0]);
1035 if (pinned[1])
1036 page_cache_release(pinned[1]);
1037 *ppos = pos;
1038
1039 if (num_written > 0 && will_write) {
1040 struct btrfs_trans_handle *trans;
1041
1042 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1043 if (err)
1044 num_written = err;
1045
1046 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
1047 trans = btrfs_start_transaction(root, 1);
1048 ret = btrfs_log_dentry_safe(trans, root,
1049 file->f_dentry);
1050 if (ret == 0) {
1051 btrfs_sync_log(trans, root);
1052 btrfs_end_transaction(trans, root);
1053 } else {
1054 btrfs_commit_transaction(trans, root);
1055 }
1056 }
1057 if (file->f_flags & O_DIRECT) {
1058 invalidate_mapping_pages(inode->i_mapping,
1059 start_pos >> PAGE_CACHE_SHIFT,
1060 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1061 }
1062 }
1063 current->backing_dev_info = NULL;
1064 return num_written ? num_written : err;
1065 }
1066
1067 int btrfs_release_file(struct inode * inode, struct file * filp)
1068 {
1069 if (filp->private_data)
1070 btrfs_ioctl_trans_end(filp);
1071 return 0;
1072 }
1073
1074 /*
1075 * fsync call for both files and directories. This logs the inode into
1076 * the tree log instead of forcing full commits whenever possible.
1077 *
1078 * It needs to call filemap_fdatawait so that all ordered extent updates are
1079 * in the metadata btree are up to date for copying to the log.
1080 *
1081 * It drops the inode mutex before doing the tree log commit. This is an
1082 * important optimization for directories because holding the mutex prevents
1083 * new operations on the dir while we write to disk.
1084 */
1085 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
1086 {
1087 struct inode *inode = dentry->d_inode;
1088 struct btrfs_root *root = BTRFS_I(inode)->root;
1089 int ret = 0;
1090 struct btrfs_trans_handle *trans;
1091
1092 /*
1093 * check the transaction that last modified this inode
1094 * and see if its already been committed
1095 */
1096 if (!BTRFS_I(inode)->last_trans)
1097 goto out;
1098
1099 mutex_lock(&root->fs_info->trans_mutex);
1100 if (BTRFS_I(inode)->last_trans <=
1101 root->fs_info->last_trans_committed) {
1102 BTRFS_I(inode)->last_trans = 0;
1103 mutex_unlock(&root->fs_info->trans_mutex);
1104 goto out;
1105 }
1106 mutex_unlock(&root->fs_info->trans_mutex);
1107
1108 root->fs_info->tree_log_batch++;
1109 filemap_fdatawait(inode->i_mapping);
1110 root->fs_info->tree_log_batch++;
1111
1112 /*
1113 * ok we haven't committed the transaction yet, lets do a commit
1114 */
1115 if (file->private_data)
1116 btrfs_ioctl_trans_end(file);
1117
1118 trans = btrfs_start_transaction(root, 1);
1119 if (!trans) {
1120 ret = -ENOMEM;
1121 goto out;
1122 }
1123
1124 ret = btrfs_log_dentry_safe(trans, root, file->f_dentry);
1125 if (ret < 0) {
1126 goto out;
1127 }
1128
1129 /* we've logged all the items and now have a consistent
1130 * version of the file in the log. It is possible that
1131 * someone will come in and modify the file, but that's
1132 * fine because the log is consistent on disk, and we
1133 * have references to all of the file's extents
1134 *
1135 * It is possible that someone will come in and log the
1136 * file again, but that will end up using the synchronization
1137 * inside btrfs_sync_log to keep things safe.
1138 */
1139 mutex_unlock(&file->f_dentry->d_inode->i_mutex);
1140
1141 if (ret > 0) {
1142 ret = btrfs_commit_transaction(trans, root);
1143 } else {
1144 btrfs_sync_log(trans, root);
1145 ret = btrfs_end_transaction(trans, root);
1146 }
1147 mutex_lock(&file->f_dentry->d_inode->i_mutex);
1148 out:
1149 return ret > 0 ? EIO : ret;
1150 }
1151
1152 static struct vm_operations_struct btrfs_file_vm_ops = {
1153 .fault = filemap_fault,
1154 .page_mkwrite = btrfs_page_mkwrite,
1155 };
1156
1157 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1158 {
1159 vma->vm_ops = &btrfs_file_vm_ops;
1160 file_accessed(filp);
1161 return 0;
1162 }
1163
1164 struct file_operations btrfs_file_operations = {
1165 .llseek = generic_file_llseek,
1166 .read = do_sync_read,
1167 .aio_read = generic_file_aio_read,
1168 .splice_read = generic_file_splice_read,
1169 .write = btrfs_file_write,
1170 .mmap = btrfs_file_mmap,
1171 .open = generic_file_open,
1172 .release = btrfs_release_file,
1173 .fsync = btrfs_sync_file,
1174 .unlocked_ioctl = btrfs_ioctl,
1175 #ifdef CONFIG_COMPAT
1176 .compat_ioctl = btrfs_ioctl,
1177 #endif
1178 };
(deprecated) Btrfs devel tree