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Btrfs: Replace the transaction work queue with kthreads
[deliverable/linux.git] / fs / btrfs / file.c
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 "ordered-data.h"
38 #include "ioctl.h"
39 #include "print-tree.h"
40 #include "compat.h"
41
42
43 static int btrfs_copy_from_user(loff_t pos, int num_pages, int write_bytes,
44 struct page **prepared_pages,
45 const char __user * buf)
46 {
47 long page_fault = 0;
48 int i;
49 int offset = pos & (PAGE_CACHE_SIZE - 1);
50
51 for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
52 size_t count = min_t(size_t,
53 PAGE_CACHE_SIZE - offset, write_bytes);
54 struct page *page = prepared_pages[i];
55 fault_in_pages_readable(buf, count);
56
57 /* Copy data from userspace to the current page */
58 kmap(page);
59 page_fault = __copy_from_user(page_address(page) + offset,
60 buf, count);
61 /* Flush processor's dcache for this page */
62 flush_dcache_page(page);
63 kunmap(page);
64 buf += count;
65 write_bytes -= count;
66
67 if (page_fault)
68 break;
69 }
70 return page_fault ? -EFAULT : 0;
71 }
72
73 static void btrfs_drop_pages(struct page **pages, size_t num_pages)
74 {
75 size_t i;
76 for (i = 0; i < num_pages; i++) {
77 if (!pages[i])
78 break;
79 unlock_page(pages[i]);
80 mark_page_accessed(pages[i]);
81 page_cache_release(pages[i]);
82 }
83 }
84
85 static int noinline insert_inline_extent(struct btrfs_trans_handle *trans,
86 struct btrfs_root *root, struct inode *inode,
87 u64 offset, size_t size,
88 struct page **pages, size_t page_offset,
89 int num_pages)
90 {
91 struct btrfs_key key;
92 struct btrfs_path *path;
93 struct extent_buffer *leaf;
94 char *kaddr;
95 unsigned long ptr;
96 struct btrfs_file_extent_item *ei;
97 struct page *page;
98 u32 datasize;
99 int err = 0;
100 int ret;
101 int i;
102 ssize_t cur_size;
103
104 path = btrfs_alloc_path();
105 if (!path)
106 return -ENOMEM;
107
108 btrfs_set_trans_block_group(trans, inode);
109
110 key.objectid = inode->i_ino;
111 key.offset = offset;
112 btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
113
114 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
115 if (ret < 0) {
116 err = ret;
117 goto fail;
118 }
119 if (ret == 1) {
120 struct btrfs_key found_key;
121
122 if (path->slots[0] == 0)
123 goto insert;
124
125 path->slots[0]--;
126 leaf = path->nodes[0];
127 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
128
129 if (found_key.objectid != inode->i_ino)
130 goto insert;
131
132 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
133 goto insert;
134 ei = btrfs_item_ptr(leaf, path->slots[0],
135 struct btrfs_file_extent_item);
136
137 if (btrfs_file_extent_type(leaf, ei) !=
138 BTRFS_FILE_EXTENT_INLINE) {
139 goto insert;
140 }
141 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
142 ret = 0;
143 }
144 if (ret == 0) {
145 u32 found_size;
146 u64 found_end;
147
148 leaf = path->nodes[0];
149 ei = btrfs_item_ptr(leaf, path->slots[0],
150 struct btrfs_file_extent_item);
151
152 if (btrfs_file_extent_type(leaf, ei) !=
153 BTRFS_FILE_EXTENT_INLINE) {
154 err = ret;
155 btrfs_print_leaf(root, leaf);
156 printk("found wasn't inline offset %Lu inode %lu\n",
157 offset, inode->i_ino);
158 goto fail;
159 }
160 found_size = btrfs_file_extent_inline_len(leaf,
161 btrfs_item_nr(leaf, path->slots[0]));
162 found_end = key.offset + found_size;
163
164 if (found_end < offset + size) {
165 btrfs_release_path(root, path);
166 ret = btrfs_search_slot(trans, root, &key, path,
167 offset + size - found_end, 1);
168 BUG_ON(ret != 0);
169
170 ret = btrfs_extend_item(trans, root, path,
171 offset + size - found_end);
172 if (ret) {
173 err = ret;
174 goto fail;
175 }
176 leaf = path->nodes[0];
177 ei = btrfs_item_ptr(leaf, path->slots[0],
178 struct btrfs_file_extent_item);
179 inode->i_blocks += (offset + size - found_end) >> 9;
180 }
181 if (found_end < offset) {
182 ptr = btrfs_file_extent_inline_start(ei) + found_size;
183 memset_extent_buffer(leaf, 0, ptr, offset - found_end);
184 }
185 } else {
186 insert:
187 btrfs_release_path(root, path);
188 datasize = offset + size - key.offset;
189 inode->i_blocks += datasize >> 9;
190 datasize = btrfs_file_extent_calc_inline_size(datasize);
191 ret = btrfs_insert_empty_item(trans, root, path, &key,
192 datasize);
193 if (ret) {
194 err = ret;
195 printk("got bad ret %d\n", ret);
196 goto fail;
197 }
198 leaf = path->nodes[0];
199 ei = btrfs_item_ptr(leaf, path->slots[0],
200 struct btrfs_file_extent_item);
201 btrfs_set_file_extent_generation(leaf, ei, trans->transid);
202 btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
203 }
204 ptr = btrfs_file_extent_inline_start(ei) + offset - key.offset;
205
206 cur_size = size;
207 i = 0;
208 while (size > 0) {
209 page = pages[i];
210 kaddr = kmap_atomic(page, KM_USER0);
211 cur_size = min_t(size_t, PAGE_CACHE_SIZE - page_offset, size);
212 write_extent_buffer(leaf, kaddr + page_offset, ptr, cur_size);
213 kunmap_atomic(kaddr, KM_USER0);
214 page_offset = 0;
215 ptr += cur_size;
216 size -= cur_size;
217 if (i >= num_pages) {
218 printk("i %d num_pages %d\n", i, num_pages);
219 }
220 i++;
221 }
222 btrfs_mark_buffer_dirty(leaf);
223 fail:
224 btrfs_free_path(path);
225 return err;
226 }
227
228 static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
229 struct btrfs_root *root,
230 struct file *file,
231 struct page **pages,
232 size_t num_pages,
233 loff_t pos,
234 size_t write_bytes)
235 {
236 int err = 0;
237 int i;
238 struct inode *inode = fdentry(file)->d_inode;
239 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
240 u64 hint_byte;
241 u64 num_bytes;
242 u64 start_pos;
243 u64 end_of_last_block;
244 u64 end_pos = pos + write_bytes;
245 u64 inline_size;
246 loff_t isize = i_size_read(inode);
247
248 start_pos = pos & ~((u64)root->sectorsize - 1);
249 num_bytes = (write_bytes + pos - start_pos +
250 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
251
252 end_of_last_block = start_pos + num_bytes - 1;
253
254 lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
255 trans = btrfs_start_transaction(root, 1);
256 if (!trans) {
257 err = -ENOMEM;
258 goto out_unlock;
259 }
260 btrfs_set_trans_block_group(trans, inode);
261 hint_byte = 0;
262
263 if ((end_of_last_block & 4095) == 0) {
264 printk("strange end of last %Lu %zu %Lu\n", start_pos, write_bytes, end_of_last_block);
265 }
266 set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
267
268 /* FIXME...EIEIO, ENOSPC and more */
269 /* insert any holes we need to create */
270 if (isize < end_pos) {
271 u64 last_pos_in_file;
272 u64 hole_size;
273 u64 mask = root->sectorsize - 1;
274 last_pos_in_file = (isize + mask) & ~mask;
275 hole_size = (end_pos - last_pos_in_file + mask) & ~mask;
276 if (last_pos_in_file < end_pos) {
277 err = btrfs_drop_extents(trans, root, inode,
278 last_pos_in_file,
279 last_pos_in_file + hole_size,
280 last_pos_in_file,
281 &hint_byte);
282 if (err)
283 goto failed;
284
285 err = btrfs_insert_file_extent(trans, root,
286 inode->i_ino,
287 last_pos_in_file,
288 0, 0, hole_size, 0);
289 btrfs_drop_extent_cache(inode, last_pos_in_file,
290 last_pos_in_file + hole_size -1);
291 btrfs_check_file(root, inode);
292 }
293 if (err)
294 goto failed;
295 }
296
297 /*
298 * either allocate an extent for the new bytes or setup the key
299 * to show we are doing inline data in the extent
300 */
301 inline_size = end_pos;
302 if (isize >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
303 inline_size > root->fs_info->max_inline ||
304 (inline_size & (root->sectorsize -1)) == 0 ||
305 inline_size >= BTRFS_MAX_INLINE_DATA_SIZE(root)) {
306 u64 last_end;
307
308 for (i = 0; i < num_pages; i++) {
309 struct page *p = pages[i];
310 SetPageUptodate(p);
311 set_page_dirty(p);
312 }
313 last_end = (u64)(pages[num_pages -1]->index) <<
314 PAGE_CACHE_SHIFT;
315 last_end += PAGE_CACHE_SIZE - 1;
316 set_extent_delalloc(io_tree, start_pos, end_of_last_block,
317 GFP_NOFS);
318 btrfs_add_ordered_inode(inode);
319 } else {
320 u64 aligned_end;
321 /* step one, delete the existing extents in this range */
322 aligned_end = (pos + write_bytes + root->sectorsize - 1) &
323 ~((u64)root->sectorsize - 1);
324 err = btrfs_drop_extents(trans, root, inode, start_pos,
325 aligned_end, aligned_end, &hint_byte);
326 if (err)
327 goto failed;
328 if (isize > inline_size)
329 inline_size = min_t(u64, isize, aligned_end);
330 inline_size -= start_pos;
331 err = insert_inline_extent(trans, root, inode, start_pos,
332 inline_size, pages, 0, num_pages);
333 btrfs_drop_extent_cache(inode, start_pos, aligned_end - 1);
334 BUG_ON(err);
335 }
336 if (end_pos > isize) {
337 i_size_write(inode, end_pos);
338 btrfs_update_inode(trans, root, inode);
339 }
340 failed:
341 err = btrfs_end_transaction(trans, root);
342 out_unlock:
343 unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
344 return err;
345 }
346
347 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
348 {
349 struct extent_map *em;
350 struct extent_map *split = NULL;
351 struct extent_map *split2 = NULL;
352 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
353 u64 len = end - start + 1;
354 int ret;
355 int testend = 1;
356
357 if (end == (u64)-1) {
358 len = (u64)-1;
359 testend = 0;
360 }
361 while(1) {
362 if (!split)
363 split = alloc_extent_map(GFP_NOFS);
364 if (!split2)
365 split2 = alloc_extent_map(GFP_NOFS);
366
367 spin_lock(&em_tree->lock);
368 em = lookup_extent_mapping(em_tree, start, len);
369 if (!em) {
370 spin_unlock(&em_tree->lock);
371 break;
372 }
373 remove_extent_mapping(em_tree, em);
374
375 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
376 em->start < start) {
377 split->start = em->start;
378 split->len = start - em->start;
379 split->block_start = em->block_start;
380 split->bdev = em->bdev;
381 split->flags = em->flags;
382 ret = add_extent_mapping(em_tree, split);
383 BUG_ON(ret);
384 free_extent_map(split);
385 split = split2;
386 split2 = NULL;
387 }
388 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
389 testend && em->start + em->len > start + len) {
390 u64 diff = start + len - em->start;
391
392 split->start = start + len;
393 split->len = em->start + em->len - (start + len);
394 split->bdev = em->bdev;
395 split->flags = em->flags;
396
397 split->block_start = em->block_start + diff;
398
399 ret = add_extent_mapping(em_tree, split);
400 BUG_ON(ret);
401 free_extent_map(split);
402 split = NULL;
403 }
404 spin_unlock(&em_tree->lock);
405
406 /* once for us */
407 free_extent_map(em);
408 /* once for the tree*/
409 free_extent_map(em);
410 }
411 if (split)
412 free_extent_map(split);
413 if (split2)
414 free_extent_map(split2);
415 return 0;
416 }
417
418 int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
419 {
420 return 0;
421 #if 0
422 struct btrfs_path *path;
423 struct btrfs_key found_key;
424 struct extent_buffer *leaf;
425 struct btrfs_file_extent_item *extent;
426 u64 last_offset = 0;
427 int nritems;
428 int slot;
429 int found_type;
430 int ret;
431 int err = 0;
432 u64 extent_end = 0;
433
434 path = btrfs_alloc_path();
435 ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
436 last_offset, 0);
437 while(1) {
438 nritems = btrfs_header_nritems(path->nodes[0]);
439 if (path->slots[0] >= nritems) {
440 ret = btrfs_next_leaf(root, path);
441 if (ret)
442 goto out;
443 nritems = btrfs_header_nritems(path->nodes[0]);
444 }
445 slot = path->slots[0];
446 leaf = path->nodes[0];
447 btrfs_item_key_to_cpu(leaf, &found_key, slot);
448 if (found_key.objectid != inode->i_ino)
449 break;
450 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
451 goto out;
452
453 if (found_key.offset < last_offset) {
454 WARN_ON(1);
455 btrfs_print_leaf(root, leaf);
456 printk("inode %lu found offset %Lu expected %Lu\n",
457 inode->i_ino, found_key.offset, last_offset);
458 err = 1;
459 goto out;
460 }
461 extent = btrfs_item_ptr(leaf, slot,
462 struct btrfs_file_extent_item);
463 found_type = btrfs_file_extent_type(leaf, extent);
464 if (found_type == BTRFS_FILE_EXTENT_REG) {
465 extent_end = found_key.offset +
466 btrfs_file_extent_num_bytes(leaf, extent);
467 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
468 struct btrfs_item *item;
469 item = btrfs_item_nr(leaf, slot);
470 extent_end = found_key.offset +
471 btrfs_file_extent_inline_len(leaf, item);
472 extent_end = (extent_end + root->sectorsize - 1) &
473 ~((u64)root->sectorsize -1 );
474 }
475 last_offset = extent_end;
476 path->slots[0]++;
477 }
478 if (0 && last_offset < inode->i_size) {
479 WARN_ON(1);
480 btrfs_print_leaf(root, leaf);
481 printk("inode %lu found offset %Lu size %Lu\n", inode->i_ino,
482 last_offset, inode->i_size);
483 err = 1;
484
485 }
486 out:
487 btrfs_free_path(path);
488 return err;
489 #endif
490 }
491
492 /*
493 * this is very complex, but the basic idea is to drop all extents
494 * in the range start - end. hint_block is filled in with a block number
495 * that would be a good hint to the block allocator for this file.
496 *
497 * If an extent intersects the range but is not entirely inside the range
498 * it is either truncated or split. Anything entirely inside the range
499 * is deleted from the tree.
500 */
501 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
502 struct btrfs_root *root, struct inode *inode,
503 u64 start, u64 end, u64 inline_limit, u64 *hint_byte)
504 {
505 u64 extent_end = 0;
506 u64 search_start = start;
507 struct extent_buffer *leaf;
508 struct btrfs_file_extent_item *extent;
509 struct btrfs_path *path;
510 struct btrfs_key key;
511 struct btrfs_file_extent_item old;
512 int keep;
513 int slot;
514 int bookend;
515 int found_type;
516 int found_extent;
517 int found_inline;
518 int recow;
519 int ret;
520
521 btrfs_drop_extent_cache(inode, start, end - 1);
522
523 path = btrfs_alloc_path();
524 if (!path)
525 return -ENOMEM;
526 while(1) {
527 recow = 0;
528 btrfs_release_path(root, path);
529 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
530 search_start, -1);
531 if (ret < 0)
532 goto out;
533 if (ret > 0) {
534 if (path->slots[0] == 0) {
535 ret = 0;
536 goto out;
537 }
538 path->slots[0]--;
539 }
540 next_slot:
541 keep = 0;
542 bookend = 0;
543 found_extent = 0;
544 found_inline = 0;
545 extent = NULL;
546 leaf = path->nodes[0];
547 slot = path->slots[0];
548 ret = 0;
549 btrfs_item_key_to_cpu(leaf, &key, slot);
550 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
551 key.offset >= end) {
552 goto out;
553 }
554 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
555 key.objectid != inode->i_ino) {
556 goto out;
557 }
558 if (recow) {
559 search_start = key.offset;
560 continue;
561 }
562 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
563 extent = btrfs_item_ptr(leaf, slot,
564 struct btrfs_file_extent_item);
565 found_type = btrfs_file_extent_type(leaf, extent);
566 if (found_type == BTRFS_FILE_EXTENT_REG) {
567 extent_end =
568 btrfs_file_extent_disk_bytenr(leaf,
569 extent);
570 if (extent_end)
571 *hint_byte = extent_end;
572
573 extent_end = key.offset +
574 btrfs_file_extent_num_bytes(leaf, extent);
575 found_extent = 1;
576 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
577 struct btrfs_item *item;
578 item = btrfs_item_nr(leaf, slot);
579 found_inline = 1;
580 extent_end = key.offset +
581 btrfs_file_extent_inline_len(leaf, item);
582 }
583 } else {
584 extent_end = search_start;
585 }
586
587 /* we found nothing we can drop */
588 if ((!found_extent && !found_inline) ||
589 search_start >= extent_end) {
590 int nextret;
591 u32 nritems;
592 nritems = btrfs_header_nritems(leaf);
593 if (slot >= nritems - 1) {
594 nextret = btrfs_next_leaf(root, path);
595 if (nextret)
596 goto out;
597 recow = 1;
598 } else {
599 path->slots[0]++;
600 }
601 goto next_slot;
602 }
603
604 if (found_inline) {
605 u64 mask = root->sectorsize - 1;
606 search_start = (extent_end + mask) & ~mask;
607 } else
608 search_start = extent_end;
609 if (end <= extent_end && start >= key.offset && found_inline) {
610 *hint_byte = EXTENT_MAP_INLINE;
611 continue;
612 }
613 if (end < extent_end && end >= key.offset) {
614 if (found_extent) {
615 u64 disk_bytenr =
616 btrfs_file_extent_disk_bytenr(leaf, extent);
617 u64 disk_num_bytes =
618 btrfs_file_extent_disk_num_bytes(leaf,
619 extent);
620 read_extent_buffer(leaf, &old,
621 (unsigned long)extent,
622 sizeof(old));
623 if (disk_bytenr != 0) {
624 ret = btrfs_inc_extent_ref(trans, root,
625 disk_bytenr, disk_num_bytes,
626 root->root_key.objectid,
627 trans->transid,
628 key.objectid, end);
629 BUG_ON(ret);
630 }
631 }
632 bookend = 1;
633 if (found_inline && start <= key.offset)
634 keep = 1;
635 }
636 /* truncate existing extent */
637 if (start > key.offset) {
638 u64 new_num;
639 u64 old_num;
640 keep = 1;
641 WARN_ON(start & (root->sectorsize - 1));
642 if (found_extent) {
643 new_num = start - key.offset;
644 old_num = btrfs_file_extent_num_bytes(leaf,
645 extent);
646 *hint_byte =
647 btrfs_file_extent_disk_bytenr(leaf,
648 extent);
649 if (btrfs_file_extent_disk_bytenr(leaf,
650 extent)) {
651 dec_i_blocks(inode, old_num - new_num);
652 }
653 btrfs_set_file_extent_num_bytes(leaf, extent,
654 new_num);
655 btrfs_mark_buffer_dirty(leaf);
656 } else if (key.offset < inline_limit &&
657 (end > extent_end) &&
658 (inline_limit < extent_end)) {
659 u32 new_size;
660 new_size = btrfs_file_extent_calc_inline_size(
661 inline_limit - key.offset);
662 dec_i_blocks(inode, (extent_end - key.offset) -
663 (inline_limit - key.offset));
664 btrfs_truncate_item(trans, root, path,
665 new_size, 1);
666 }
667 }
668 /* delete the entire extent */
669 if (!keep) {
670 u64 disk_bytenr = 0;
671 u64 disk_num_bytes = 0;
672 u64 extent_num_bytes = 0;
673 u64 root_gen;
674 u64 root_owner;
675
676 root_gen = btrfs_header_generation(leaf);
677 root_owner = btrfs_header_owner(leaf);
678 if (found_extent) {
679 disk_bytenr =
680 btrfs_file_extent_disk_bytenr(leaf,
681 extent);
682 disk_num_bytes =
683 btrfs_file_extent_disk_num_bytes(leaf,
684 extent);
685 extent_num_bytes =
686 btrfs_file_extent_num_bytes(leaf, extent);
687 *hint_byte =
688 btrfs_file_extent_disk_bytenr(leaf,
689 extent);
690 }
691 ret = btrfs_del_item(trans, root, path);
692 /* TODO update progress marker and return */
693 BUG_ON(ret);
694 btrfs_release_path(root, path);
695 extent = NULL;
696 if (found_extent && disk_bytenr != 0) {
697 dec_i_blocks(inode, extent_num_bytes);
698 ret = btrfs_free_extent(trans, root,
699 disk_bytenr,
700 disk_num_bytes,
701 root_owner,
702 root_gen, inode->i_ino,
703 key.offset, 0);
704 }
705
706 BUG_ON(ret);
707 if (!bookend && search_start >= end) {
708 ret = 0;
709 goto out;
710 }
711 if (!bookend)
712 continue;
713 }
714 if (bookend && found_inline && start <= key.offset) {
715 u32 new_size;
716 new_size = btrfs_file_extent_calc_inline_size(
717 extent_end - end);
718 dec_i_blocks(inode, (extent_end - key.offset) -
719 (extent_end - end));
720 btrfs_truncate_item(trans, root, path, new_size, 0);
721 }
722 /* create bookend, splitting the extent in two */
723 if (bookend && found_extent) {
724 struct btrfs_key ins;
725 ins.objectid = inode->i_ino;
726 ins.offset = end;
727 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
728 btrfs_release_path(root, path);
729 ret = btrfs_insert_empty_item(trans, root, path, &ins,
730 sizeof(*extent));
731
732 leaf = path->nodes[0];
733 if (ret) {
734 btrfs_print_leaf(root, leaf);
735 printk("got %d on inserting %Lu %u %Lu start %Lu end %Lu found %Lu %Lu keep was %d\n", ret , ins.objectid, ins.type, ins.offset, start, end, key.offset, extent_end, keep);
736 }
737 BUG_ON(ret);
738 extent = btrfs_item_ptr(leaf, path->slots[0],
739 struct btrfs_file_extent_item);
740 write_extent_buffer(leaf, &old,
741 (unsigned long)extent, sizeof(old));
742
743 btrfs_set_file_extent_offset(leaf, extent,
744 le64_to_cpu(old.offset) + end - key.offset);
745 WARN_ON(le64_to_cpu(old.num_bytes) <
746 (extent_end - end));
747 btrfs_set_file_extent_num_bytes(leaf, extent,
748 extent_end - end);
749 btrfs_set_file_extent_type(leaf, extent,
750 BTRFS_FILE_EXTENT_REG);
751
752 btrfs_mark_buffer_dirty(path->nodes[0]);
753 if (le64_to_cpu(old.disk_bytenr) != 0) {
754 inode->i_blocks +=
755 btrfs_file_extent_num_bytes(leaf,
756 extent) >> 9;
757 }
758 ret = 0;
759 goto out;
760 }
761 }
762 out:
763 btrfs_free_path(path);
764 btrfs_check_file(root, inode);
765 return ret;
766 }
767
768 /*
769 * this gets pages into the page cache and locks them down
770 */
771 static int prepare_pages(struct btrfs_root *root, struct file *file,
772 struct page **pages, size_t num_pages,
773 loff_t pos, unsigned long first_index,
774 unsigned long last_index, size_t write_bytes)
775 {
776 int i;
777 unsigned long index = pos >> PAGE_CACHE_SHIFT;
778 struct inode *inode = fdentry(file)->d_inode;
779 int err = 0;
780 u64 start_pos;
781
782 start_pos = pos & ~((u64)root->sectorsize - 1);
783
784 memset(pages, 0, num_pages * sizeof(struct page *));
785
786 for (i = 0; i < num_pages; i++) {
787 pages[i] = grab_cache_page(inode->i_mapping, index + i);
788 if (!pages[i]) {
789 err = -ENOMEM;
790 BUG_ON(1);
791 }
792 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
793 ClearPageDirty(pages[i]);
794 #else
795 cancel_dirty_page(pages[i], PAGE_CACHE_SIZE);
796 #endif
797 wait_on_page_writeback(pages[i]);
798 set_page_extent_mapped(pages[i]);
799 WARN_ON(!PageLocked(pages[i]));
800 }
801 if (start_pos < inode->i_size) {
802 u64 last_pos;
803 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
804 lock_extent(&BTRFS_I(inode)->io_tree,
805 start_pos, last_pos - 1, GFP_NOFS);
806 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
807 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
808 GFP_NOFS);
809 unlock_extent(&BTRFS_I(inode)->io_tree,
810 start_pos, last_pos - 1, GFP_NOFS);
811 }
812 return 0;
813 }
814
815 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
816 size_t count, loff_t *ppos)
817 {
818 loff_t pos;
819 loff_t start_pos;
820 ssize_t num_written = 0;
821 ssize_t err = 0;
822 int ret = 0;
823 struct inode *inode = fdentry(file)->d_inode;
824 struct btrfs_root *root = BTRFS_I(inode)->root;
825 struct page **pages = NULL;
826 int nrptrs;
827 struct page *pinned[2];
828 unsigned long first_index;
829 unsigned long last_index;
830
831 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
832 PAGE_CACHE_SIZE / (sizeof(struct page *)));
833 pinned[0] = NULL;
834 pinned[1] = NULL;
835
836 pos = *ppos;
837 start_pos = pos;
838
839 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
840 current->backing_dev_info = inode->i_mapping->backing_dev_info;
841 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
842 if (err)
843 goto out_nolock;
844 if (count == 0)
845 goto out_nolock;
846 #ifdef REMOVE_SUID_PATH
847 err = remove_suid(&file->f_path);
848 #else
849 err = remove_suid(fdentry(file));
850 #endif
851 if (err)
852 goto out_nolock;
853 file_update_time(file);
854
855 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
856
857 mutex_lock(&inode->i_mutex);
858 first_index = pos >> PAGE_CACHE_SHIFT;
859 last_index = (pos + count) >> PAGE_CACHE_SHIFT;
860
861 /*
862 * if this is a nodatasum mount, force summing off for the inode
863 * all the time. That way a later mount with summing on won't
864 * get confused
865 */
866 if (btrfs_test_opt(root, NODATASUM))
867 btrfs_set_flag(inode, NODATASUM);
868
869 /*
870 * there are lots of better ways to do this, but this code
871 * makes sure the first and last page in the file range are
872 * up to date and ready for cow
873 */
874 if ((pos & (PAGE_CACHE_SIZE - 1))) {
875 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
876 if (!PageUptodate(pinned[0])) {
877 ret = btrfs_readpage(NULL, pinned[0]);
878 BUG_ON(ret);
879 wait_on_page_locked(pinned[0]);
880 } else {
881 unlock_page(pinned[0]);
882 }
883 }
884 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
885 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
886 if (!PageUptodate(pinned[1])) {
887 ret = btrfs_readpage(NULL, pinned[1]);
888 BUG_ON(ret);
889 wait_on_page_locked(pinned[1]);
890 } else {
891 unlock_page(pinned[1]);
892 }
893 }
894
895 while(count > 0) {
896 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
897 size_t write_bytes = min(count, nrptrs *
898 (size_t)PAGE_CACHE_SIZE -
899 offset);
900 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
901 PAGE_CACHE_SHIFT;
902
903 WARN_ON(num_pages > nrptrs);
904 memset(pages, 0, sizeof(pages));
905
906 ret = btrfs_check_free_space(root, write_bytes, 0);
907 if (ret)
908 goto out;
909
910 ret = prepare_pages(root, file, pages, num_pages,
911 pos, first_index, last_index,
912 write_bytes);
913 if (ret)
914 goto out;
915
916 ret = btrfs_copy_from_user(pos, num_pages,
917 write_bytes, pages, buf);
918 if (ret) {
919 btrfs_drop_pages(pages, num_pages);
920 goto out;
921 }
922
923 ret = dirty_and_release_pages(NULL, root, file, pages,
924 num_pages, pos, write_bytes);
925 btrfs_drop_pages(pages, num_pages);
926 if (ret)
927 goto out;
928
929 buf += write_bytes;
930 count -= write_bytes;
931 pos += write_bytes;
932 num_written += write_bytes;
933
934 balance_dirty_pages_ratelimited_nr(inode->i_mapping, num_pages);
935 if (num_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
936 btrfs_btree_balance_dirty(root, 1);
937 cond_resched();
938 }
939 out:
940 mutex_unlock(&inode->i_mutex);
941
942 out_nolock:
943 kfree(pages);
944 if (pinned[0])
945 page_cache_release(pinned[0]);
946 if (pinned[1])
947 page_cache_release(pinned[1]);
948 *ppos = pos;
949
950 if (num_written > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
951 err = sync_page_range(inode, inode->i_mapping,
952 start_pos, num_written);
953 if (err < 0)
954 num_written = err;
955 } else if (num_written > 0 && (file->f_flags & O_DIRECT)) {
956 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
957 do_sync_file_range(file, start_pos,
958 start_pos + num_written - 1,
959 SYNC_FILE_RANGE_WRITE |
960 SYNC_FILE_RANGE_WAIT_AFTER);
961 #else
962 do_sync_mapping_range(inode->i_mapping, start_pos,
963 start_pos + num_written - 1,
964 SYNC_FILE_RANGE_WRITE |
965 SYNC_FILE_RANGE_WAIT_AFTER);
966 #endif
967 invalidate_mapping_pages(inode->i_mapping,
968 start_pos >> PAGE_CACHE_SHIFT,
969 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
970 }
971 current->backing_dev_info = NULL;
972 btrfs_ordered_throttle(root, inode);
973 return num_written ? num_written : err;
974 }
975
976 int btrfs_release_file(struct inode * inode, struct file * filp)
977 {
978 btrfs_del_ordered_inode(inode, 0);
979 if (filp->private_data)
980 btrfs_ioctl_trans_end(filp);
981 return 0;
982 }
983
984 static int btrfs_sync_file(struct file *file,
985 struct dentry *dentry, int datasync)
986 {
987 struct inode *inode = dentry->d_inode;
988 struct btrfs_root *root = BTRFS_I(inode)->root;
989 int ret = 0;
990 struct btrfs_trans_handle *trans;
991
992 /*
993 * check the transaction that last modified this inode
994 * and see if its already been committed
995 */
996 if (!BTRFS_I(inode)->last_trans)
997 goto out;
998
999 mutex_lock(&root->fs_info->trans_mutex);
1000 if (BTRFS_I(inode)->last_trans <=
1001 root->fs_info->last_trans_committed) {
1002 BTRFS_I(inode)->last_trans = 0;
1003 mutex_unlock(&root->fs_info->trans_mutex);
1004 goto out;
1005 }
1006 mutex_unlock(&root->fs_info->trans_mutex);
1007
1008 /*
1009 * ok we haven't committed the transaction yet, lets do a commit
1010 */
1011 if (file->private_data)
1012 btrfs_ioctl_trans_end(file);
1013
1014 trans = btrfs_start_transaction(root, 1);
1015 if (!trans) {
1016 ret = -ENOMEM;
1017 goto out;
1018 }
1019 ret = btrfs_commit_transaction(trans, root);
1020 out:
1021 return ret > 0 ? EIO : ret;
1022 }
1023
1024 static struct vm_operations_struct btrfs_file_vm_ops = {
1025 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
1026 .nopage = filemap_nopage,
1027 .populate = filemap_populate,
1028 #else
1029 .fault = filemap_fault,
1030 #endif
1031 .page_mkwrite = btrfs_page_mkwrite,
1032 };
1033
1034 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1035 {
1036 vma->vm_ops = &btrfs_file_vm_ops;
1037 file_accessed(filp);
1038 return 0;
1039 }
1040
1041 struct file_operations btrfs_file_operations = {
1042 .llseek = generic_file_llseek,
1043 .read = do_sync_read,
1044 .aio_read = generic_file_aio_read,
1045 .splice_read = generic_file_splice_read,
1046 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
1047 .sendfile = generic_file_sendfile,
1048 #endif
1049 .write = btrfs_file_write,
1050 .mmap = btrfs_file_mmap,
1051 .open = generic_file_open,
1052 .release = btrfs_release_file,
1053 .fsync = btrfs_sync_file,
1054 .unlocked_ioctl = btrfs_ioctl,
1055 #ifdef CONFIG_COMPAT
1056 .compat_ioctl = btrfs_ioctl,
1057 #endif
1058 };
1059
Linux kernel - Deliverables
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