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Btrfs: Add a write ahead tree log to optimize synchronous operations
[deliverable/linux.git] / fs / btrfs / disk-io.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/version.h>
20 #include <linux/fs.h>
21 #include <linux/blkdev.h>
22 #include <linux/scatterlist.h>
23 #include <linux/swap.h>
24 #include <linux/radix-tree.h>
25 #include <linux/writeback.h>
26 #include <linux/buffer_head.h> // for block_sync_page
27 #include <linux/workqueue.h>
28 #include <linux/kthread.h>
29 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20)
30 # include <linux/freezer.h>
31 #else
32 # include <linux/sched.h>
33 #endif
34 #include "crc32c.h"
35 #include "ctree.h"
36 #include "disk-io.h"
37 #include "transaction.h"
38 #include "btrfs_inode.h"
39 #include "volumes.h"
40 #include "print-tree.h"
41 #include "async-thread.h"
42 #include "locking.h"
43 #include "ref-cache.h"
44 #include "tree-log.h"
45
46 #if 0
47 static int check_tree_block(struct btrfs_root *root, struct extent_buffer *buf)
48 {
49 if (extent_buffer_blocknr(buf) != btrfs_header_blocknr(buf)) {
50 printk(KERN_CRIT "buf blocknr(buf) is %llu, header is %llu\n",
51 (unsigned long long)extent_buffer_blocknr(buf),
52 (unsigned long long)btrfs_header_blocknr(buf));
53 return 1;
54 }
55 return 0;
56 }
57 #endif
58
59 static struct extent_io_ops btree_extent_io_ops;
60 static void end_workqueue_fn(struct btrfs_work *work);
61
62 struct end_io_wq {
63 struct bio *bio;
64 bio_end_io_t *end_io;
65 void *private;
66 struct btrfs_fs_info *info;
67 int error;
68 int metadata;
69 struct list_head list;
70 struct btrfs_work work;
71 };
72
73 struct async_submit_bio {
74 struct inode *inode;
75 struct bio *bio;
76 struct list_head list;
77 extent_submit_bio_hook_t *submit_bio_hook;
78 int rw;
79 int mirror_num;
80 struct btrfs_work work;
81 };
82
83 struct extent_map *btree_get_extent(struct inode *inode, struct page *page,
84 size_t page_offset, u64 start, u64 len,
85 int create)
86 {
87 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
88 struct extent_map *em;
89 int ret;
90
91 spin_lock(&em_tree->lock);
92 em = lookup_extent_mapping(em_tree, start, len);
93 if (em) {
94 em->bdev =
95 BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
96 spin_unlock(&em_tree->lock);
97 goto out;
98 }
99 spin_unlock(&em_tree->lock);
100
101 em = alloc_extent_map(GFP_NOFS);
102 if (!em) {
103 em = ERR_PTR(-ENOMEM);
104 goto out;
105 }
106 em->start = 0;
107 em->len = (u64)-1;
108 em->block_start = 0;
109 em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
110
111 spin_lock(&em_tree->lock);
112 ret = add_extent_mapping(em_tree, em);
113 if (ret == -EEXIST) {
114 u64 failed_start = em->start;
115 u64 failed_len = em->len;
116
117 printk("failed to insert %Lu %Lu -> %Lu into tree\n",
118 em->start, em->len, em->block_start);
119 free_extent_map(em);
120 em = lookup_extent_mapping(em_tree, start, len);
121 if (em) {
122 printk("after failing, found %Lu %Lu %Lu\n",
123 em->start, em->len, em->block_start);
124 ret = 0;
125 } else {
126 em = lookup_extent_mapping(em_tree, failed_start,
127 failed_len);
128 if (em) {
129 printk("double failure lookup gives us "
130 "%Lu %Lu -> %Lu\n", em->start,
131 em->len, em->block_start);
132 free_extent_map(em);
133 }
134 ret = -EIO;
135 }
136 } else if (ret) {
137 free_extent_map(em);
138 em = NULL;
139 }
140 spin_unlock(&em_tree->lock);
141
142 if (ret)
143 em = ERR_PTR(ret);
144 out:
145 return em;
146 }
147
148 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
149 {
150 return btrfs_crc32c(seed, data, len);
151 }
152
153 void btrfs_csum_final(u32 crc, char *result)
154 {
155 *(__le32 *)result = ~cpu_to_le32(crc);
156 }
157
158 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
159 int verify)
160 {
161 char result[BTRFS_CRC32_SIZE];
162 unsigned long len;
163 unsigned long cur_len;
164 unsigned long offset = BTRFS_CSUM_SIZE;
165 char *map_token = NULL;
166 char *kaddr;
167 unsigned long map_start;
168 unsigned long map_len;
169 int err;
170 u32 crc = ~(u32)0;
171
172 len = buf->len - offset;
173 while(len > 0) {
174 err = map_private_extent_buffer(buf, offset, 32,
175 &map_token, &kaddr,
176 &map_start, &map_len, KM_USER0);
177 if (err) {
178 printk("failed to map extent buffer! %lu\n",
179 offset);
180 return 1;
181 }
182 cur_len = min(len, map_len - (offset - map_start));
183 crc = btrfs_csum_data(root, kaddr + offset - map_start,
184 crc, cur_len);
185 len -= cur_len;
186 offset += cur_len;
187 unmap_extent_buffer(buf, map_token, KM_USER0);
188 }
189 btrfs_csum_final(crc, result);
190
191 if (verify) {
192 /* FIXME, this is not good */
193 if (memcmp_extent_buffer(buf, result, 0, BTRFS_CRC32_SIZE)) {
194 u32 val;
195 u32 found = 0;
196 memcpy(&found, result, BTRFS_CRC32_SIZE);
197
198 read_extent_buffer(buf, &val, 0, BTRFS_CRC32_SIZE);
199 printk("btrfs: %s checksum verify failed on %llu "
200 "wanted %X found %X level %d\n",
201 root->fs_info->sb->s_id,
202 buf->start, val, found, btrfs_header_level(buf));
203 return 1;
204 }
205 } else {
206 write_extent_buffer(buf, result, 0, BTRFS_CRC32_SIZE);
207 }
208 return 0;
209 }
210
211 static int verify_parent_transid(struct extent_io_tree *io_tree,
212 struct extent_buffer *eb, u64 parent_transid)
213 {
214 int ret;
215
216 if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
217 return 0;
218
219 lock_extent(io_tree, eb->start, eb->start + eb->len - 1, GFP_NOFS);
220 if (extent_buffer_uptodate(io_tree, eb) &&
221 btrfs_header_generation(eb) == parent_transid) {
222 ret = 0;
223 goto out;
224 }
225 printk("parent transid verify failed on %llu wanted %llu found %llu\n",
226 (unsigned long long)eb->start,
227 (unsigned long long)parent_transid,
228 (unsigned long long)btrfs_header_generation(eb));
229 ret = 1;
230 clear_extent_buffer_uptodate(io_tree, eb);
231 out:
232 unlock_extent(io_tree, eb->start, eb->start + eb->len - 1,
233 GFP_NOFS);
234 return ret;
235
236 }
237
238 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
239 struct extent_buffer *eb,
240 u64 start, u64 parent_transid)
241 {
242 struct extent_io_tree *io_tree;
243 int ret;
244 int num_copies = 0;
245 int mirror_num = 0;
246
247 io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
248 while (1) {
249 ret = read_extent_buffer_pages(io_tree, eb, start, 1,
250 btree_get_extent, mirror_num);
251 if (!ret &&
252 !verify_parent_transid(io_tree, eb, parent_transid))
253 return ret;
254 printk("read extent buffer pages failed with ret %d mirror no %d\n", ret, mirror_num);
255 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
256 eb->start, eb->len);
257 if (num_copies == 1)
258 return ret;
259
260 mirror_num++;
261 if (mirror_num > num_copies)
262 return ret;
263 }
264 return -EIO;
265 }
266
267 int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
268 {
269 struct extent_io_tree *tree;
270 u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
271 u64 found_start;
272 int found_level;
273 unsigned long len;
274 struct extent_buffer *eb;
275 int ret;
276
277 tree = &BTRFS_I(page->mapping->host)->io_tree;
278
279 if (page->private == EXTENT_PAGE_PRIVATE)
280 goto out;
281 if (!page->private)
282 goto out;
283 len = page->private >> 2;
284 if (len == 0) {
285 WARN_ON(1);
286 }
287 eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
288 ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE,
289 btrfs_header_generation(eb));
290 BUG_ON(ret);
291 found_start = btrfs_header_bytenr(eb);
292 if (found_start != start) {
293 printk("warning: eb start incorrect %Lu buffer %Lu len %lu\n",
294 start, found_start, len);
295 WARN_ON(1);
296 goto err;
297 }
298 if (eb->first_page != page) {
299 printk("bad first page %lu %lu\n", eb->first_page->index,
300 page->index);
301 WARN_ON(1);
302 goto err;
303 }
304 if (!PageUptodate(page)) {
305 printk("csum not up to date page %lu\n", page->index);
306 WARN_ON(1);
307 goto err;
308 }
309 found_level = btrfs_header_level(eb);
310 spin_lock(&root->fs_info->hash_lock);
311 btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
312 spin_unlock(&root->fs_info->hash_lock);
313 csum_tree_block(root, eb, 0);
314 err:
315 free_extent_buffer(eb);
316 out:
317 return 0;
318 }
319
320 static int btree_writepage_io_hook(struct page *page, u64 start, u64 end)
321 {
322 struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
323
324 csum_dirty_buffer(root, page);
325 return 0;
326 }
327
328 int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
329 struct extent_state *state)
330 {
331 struct extent_io_tree *tree;
332 u64 found_start;
333 int found_level;
334 unsigned long len;
335 struct extent_buffer *eb;
336 struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
337 int ret = 0;
338
339 tree = &BTRFS_I(page->mapping->host)->io_tree;
340 if (page->private == EXTENT_PAGE_PRIVATE)
341 goto out;
342 if (!page->private)
343 goto out;
344 len = page->private >> 2;
345 if (len == 0) {
346 WARN_ON(1);
347 }
348 eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
349
350 found_start = btrfs_header_bytenr(eb);
351 if (found_start != start) {
352 printk("bad tree block start %llu %llu\n",
353 (unsigned long long)found_start,
354 (unsigned long long)eb->start);
355 ret = -EIO;
356 goto err;
357 }
358 if (eb->first_page != page) {
359 printk("bad first page %lu %lu\n", eb->first_page->index,
360 page->index);
361 WARN_ON(1);
362 ret = -EIO;
363 goto err;
364 }
365 if (memcmp_extent_buffer(eb, root->fs_info->fsid,
366 (unsigned long)btrfs_header_fsid(eb),
367 BTRFS_FSID_SIZE)) {
368 printk("bad fsid on block %Lu\n", eb->start);
369 ret = -EIO;
370 goto err;
371 }
372 found_level = btrfs_header_level(eb);
373
374 ret = csum_tree_block(root, eb, 1);
375 if (ret)
376 ret = -EIO;
377
378 end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
379 end = eb->start + end - 1;
380 err:
381 free_extent_buffer(eb);
382 out:
383 return ret;
384 }
385
386 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
387 static void end_workqueue_bio(struct bio *bio, int err)
388 #else
389 static int end_workqueue_bio(struct bio *bio,
390 unsigned int bytes_done, int err)
391 #endif
392 {
393 struct end_io_wq *end_io_wq = bio->bi_private;
394 struct btrfs_fs_info *fs_info;
395
396 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
397 if (bio->bi_size)
398 return 1;
399 #endif
400
401 fs_info = end_io_wq->info;
402 end_io_wq->error = err;
403 end_io_wq->work.func = end_workqueue_fn;
404 end_io_wq->work.flags = 0;
405 if (bio->bi_rw & (1 << BIO_RW))
406 btrfs_queue_worker(&fs_info->endio_write_workers,
407 &end_io_wq->work);
408 else
409 btrfs_queue_worker(&fs_info->endio_workers, &end_io_wq->work);
410
411 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
412 return 0;
413 #endif
414 }
415
416 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
417 int metadata)
418 {
419 struct end_io_wq *end_io_wq;
420 end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
421 if (!end_io_wq)
422 return -ENOMEM;
423
424 end_io_wq->private = bio->bi_private;
425 end_io_wq->end_io = bio->bi_end_io;
426 end_io_wq->info = info;
427 end_io_wq->error = 0;
428 end_io_wq->bio = bio;
429 end_io_wq->metadata = metadata;
430
431 bio->bi_private = end_io_wq;
432 bio->bi_end_io = end_workqueue_bio;
433 return 0;
434 }
435
436 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
437 {
438 unsigned long limit = min_t(unsigned long,
439 info->workers.max_workers,
440 info->fs_devices->open_devices);
441 return 256 * limit;
442 }
443
444 int btrfs_congested_async(struct btrfs_fs_info *info, int iodone)
445 {
446 return atomic_read(&info->nr_async_bios) >
447 btrfs_async_submit_limit(info);
448 }
449
450 static void run_one_async_submit(struct btrfs_work *work)
451 {
452 struct btrfs_fs_info *fs_info;
453 struct async_submit_bio *async;
454 int limit;
455
456 async = container_of(work, struct async_submit_bio, work);
457 fs_info = BTRFS_I(async->inode)->root->fs_info;
458
459 limit = btrfs_async_submit_limit(fs_info);
460 limit = limit * 2 / 3;
461
462 atomic_dec(&fs_info->nr_async_submits);
463
464 if (atomic_read(&fs_info->nr_async_submits) < limit &&
465 waitqueue_active(&fs_info->async_submit_wait))
466 wake_up(&fs_info->async_submit_wait);
467
468 async->submit_bio_hook(async->inode, async->rw, async->bio,
469 async->mirror_num);
470 kfree(async);
471 }
472
473 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
474 int rw, struct bio *bio, int mirror_num,
475 extent_submit_bio_hook_t *submit_bio_hook)
476 {
477 struct async_submit_bio *async;
478 int limit = btrfs_async_submit_limit(fs_info);
479
480 async = kmalloc(sizeof(*async), GFP_NOFS);
481 if (!async)
482 return -ENOMEM;
483
484 async->inode = inode;
485 async->rw = rw;
486 async->bio = bio;
487 async->mirror_num = mirror_num;
488 async->submit_bio_hook = submit_bio_hook;
489 async->work.func = run_one_async_submit;
490 async->work.flags = 0;
491 atomic_inc(&fs_info->nr_async_submits);
492 btrfs_queue_worker(&fs_info->workers, &async->work);
493
494 if (atomic_read(&fs_info->nr_async_submits) > limit) {
495 wait_event_timeout(fs_info->async_submit_wait,
496 (atomic_read(&fs_info->nr_async_submits) < limit),
497 HZ/10);
498
499 wait_event_timeout(fs_info->async_submit_wait,
500 (atomic_read(&fs_info->nr_async_bios) < limit),
501 HZ/10);
502 }
503 return 0;
504 }
505
506 static int __btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
507 int mirror_num)
508 {
509 struct btrfs_root *root = BTRFS_I(inode)->root;
510 u64 offset;
511 int ret;
512
513 offset = bio->bi_sector << 9;
514
515 /*
516 * when we're called for a write, we're already in the async
517 * submission context. Just jump into btrfs_map_bio
518 */
519 if (rw & (1 << BIO_RW)) {
520 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
521 mirror_num, 1);
522 }
523
524 /*
525 * called for a read, do the setup so that checksum validation
526 * can happen in the async kernel threads
527 */
528 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 1);
529 BUG_ON(ret);
530
531 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
532 }
533
534 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
535 int mirror_num)
536 {
537 /*
538 * kthread helpers are used to submit writes so that checksumming
539 * can happen in parallel across all CPUs
540 */
541 if (!(rw & (1 << BIO_RW))) {
542 return __btree_submit_bio_hook(inode, rw, bio, mirror_num);
543 }
544 return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
545 inode, rw, bio, mirror_num,
546 __btree_submit_bio_hook);
547 }
548
549 static int btree_writepage(struct page *page, struct writeback_control *wbc)
550 {
551 struct extent_io_tree *tree;
552 tree = &BTRFS_I(page->mapping->host)->io_tree;
553
554 if (current->flags & PF_MEMALLOC) {
555 redirty_page_for_writepage(wbc, page);
556 unlock_page(page);
557 return 0;
558 }
559 return extent_write_full_page(tree, page, btree_get_extent, wbc);
560 }
561
562 static int btree_writepages(struct address_space *mapping,
563 struct writeback_control *wbc)
564 {
565 struct extent_io_tree *tree;
566 tree = &BTRFS_I(mapping->host)->io_tree;
567 if (wbc->sync_mode == WB_SYNC_NONE) {
568 u64 num_dirty;
569 u64 start = 0;
570 unsigned long thresh = 8 * 1024 * 1024;
571
572 if (wbc->for_kupdate)
573 return 0;
574
575 num_dirty = count_range_bits(tree, &start, (u64)-1,
576 thresh, EXTENT_DIRTY);
577 if (num_dirty < thresh) {
578 return 0;
579 }
580 }
581 return extent_writepages(tree, mapping, btree_get_extent, wbc);
582 }
583
584 int btree_readpage(struct file *file, struct page *page)
585 {
586 struct extent_io_tree *tree;
587 tree = &BTRFS_I(page->mapping->host)->io_tree;
588 return extent_read_full_page(tree, page, btree_get_extent);
589 }
590
591 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
592 {
593 struct extent_io_tree *tree;
594 struct extent_map_tree *map;
595 int ret;
596
597 tree = &BTRFS_I(page->mapping->host)->io_tree;
598 map = &BTRFS_I(page->mapping->host)->extent_tree;
599
600 ret = try_release_extent_state(map, tree, page, gfp_flags);
601 if (!ret) {
602 return 0;
603 }
604
605 ret = try_release_extent_buffer(tree, page);
606 if (ret == 1) {
607 ClearPagePrivate(page);
608 set_page_private(page, 0);
609 page_cache_release(page);
610 }
611
612 return ret;
613 }
614
615 static void btree_invalidatepage(struct page *page, unsigned long offset)
616 {
617 struct extent_io_tree *tree;
618 tree = &BTRFS_I(page->mapping->host)->io_tree;
619 extent_invalidatepage(tree, page, offset);
620 btree_releasepage(page, GFP_NOFS);
621 if (PagePrivate(page)) {
622 printk("warning page private not zero on page %Lu\n",
623 page_offset(page));
624 ClearPagePrivate(page);
625 set_page_private(page, 0);
626 page_cache_release(page);
627 }
628 }
629
630 #if 0
631 static int btree_writepage(struct page *page, struct writeback_control *wbc)
632 {
633 struct buffer_head *bh;
634 struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
635 struct buffer_head *head;
636 if (!page_has_buffers(page)) {
637 create_empty_buffers(page, root->fs_info->sb->s_blocksize,
638 (1 << BH_Dirty)|(1 << BH_Uptodate));
639 }
640 head = page_buffers(page);
641 bh = head;
642 do {
643 if (buffer_dirty(bh))
644 csum_tree_block(root, bh, 0);
645 bh = bh->b_this_page;
646 } while (bh != head);
647 return block_write_full_page(page, btree_get_block, wbc);
648 }
649 #endif
650
651 static struct address_space_operations btree_aops = {
652 .readpage = btree_readpage,
653 .writepage = btree_writepage,
654 .writepages = btree_writepages,
655 .releasepage = btree_releasepage,
656 .invalidatepage = btree_invalidatepage,
657 .sync_page = block_sync_page,
658 };
659
660 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
661 u64 parent_transid)
662 {
663 struct extent_buffer *buf = NULL;
664 struct inode *btree_inode = root->fs_info->btree_inode;
665 int ret = 0;
666
667 buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
668 if (!buf)
669 return 0;
670 read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
671 buf, 0, 0, btree_get_extent, 0);
672 free_extent_buffer(buf);
673 return ret;
674 }
675
676 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
677 u64 bytenr, u32 blocksize)
678 {
679 struct inode *btree_inode = root->fs_info->btree_inode;
680 struct extent_buffer *eb;
681 eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
682 bytenr, blocksize, GFP_NOFS);
683 return eb;
684 }
685
686 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
687 u64 bytenr, u32 blocksize)
688 {
689 struct inode *btree_inode = root->fs_info->btree_inode;
690 struct extent_buffer *eb;
691
692 eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
693 bytenr, blocksize, NULL, GFP_NOFS);
694 return eb;
695 }
696
697
698 int btrfs_write_tree_block(struct extent_buffer *buf)
699 {
700 return btrfs_fdatawrite_range(buf->first_page->mapping, buf->start,
701 buf->start + buf->len - 1, WB_SYNC_NONE);
702 }
703
704 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
705 {
706 return btrfs_wait_on_page_writeback_range(buf->first_page->mapping,
707 buf->start, buf->start + buf->len -1);
708 }
709
710 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
711 u32 blocksize, u64 parent_transid)
712 {
713 struct extent_buffer *buf = NULL;
714 struct inode *btree_inode = root->fs_info->btree_inode;
715 struct extent_io_tree *io_tree;
716 int ret;
717
718 io_tree = &BTRFS_I(btree_inode)->io_tree;
719
720 buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
721 if (!buf)
722 return NULL;
723
724 ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
725
726 if (ret == 0) {
727 buf->flags |= EXTENT_UPTODATE;
728 } else {
729 WARN_ON(1);
730 }
731 return buf;
732
733 }
734
735 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
736 struct extent_buffer *buf)
737 {
738 struct inode *btree_inode = root->fs_info->btree_inode;
739 if (btrfs_header_generation(buf) ==
740 root->fs_info->running_transaction->transid) {
741 WARN_ON(!btrfs_tree_locked(buf));
742 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
743 buf);
744 }
745 return 0;
746 }
747
748 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
749 u32 stripesize, struct btrfs_root *root,
750 struct btrfs_fs_info *fs_info,
751 u64 objectid)
752 {
753 root->node = NULL;
754 root->inode = NULL;
755 root->commit_root = NULL;
756 root->ref_tree = NULL;
757 root->sectorsize = sectorsize;
758 root->nodesize = nodesize;
759 root->leafsize = leafsize;
760 root->stripesize = stripesize;
761 root->ref_cows = 0;
762 root->track_dirty = 0;
763
764 root->fs_info = fs_info;
765 root->objectid = objectid;
766 root->last_trans = 0;
767 root->highest_inode = 0;
768 root->last_inode_alloc = 0;
769 root->name = NULL;
770 root->in_sysfs = 0;
771
772 INIT_LIST_HEAD(&root->dirty_list);
773 INIT_LIST_HEAD(&root->orphan_list);
774 INIT_LIST_HEAD(&root->dead_list);
775 spin_lock_init(&root->node_lock);
776 spin_lock_init(&root->list_lock);
777 mutex_init(&root->objectid_mutex);
778 mutex_init(&root->log_mutex);
779
780 btrfs_leaf_ref_tree_init(&root->ref_tree_struct);
781 root->ref_tree = &root->ref_tree_struct;
782
783 memset(&root->root_key, 0, sizeof(root->root_key));
784 memset(&root->root_item, 0, sizeof(root->root_item));
785 memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
786 memset(&root->root_kobj, 0, sizeof(root->root_kobj));
787 root->defrag_trans_start = fs_info->generation;
788 init_completion(&root->kobj_unregister);
789 root->defrag_running = 0;
790 root->defrag_level = 0;
791 root->root_key.objectid = objectid;
792 return 0;
793 }
794
795 static int find_and_setup_root(struct btrfs_root *tree_root,
796 struct btrfs_fs_info *fs_info,
797 u64 objectid,
798 struct btrfs_root *root)
799 {
800 int ret;
801 u32 blocksize;
802
803 __setup_root(tree_root->nodesize, tree_root->leafsize,
804 tree_root->sectorsize, tree_root->stripesize,
805 root, fs_info, objectid);
806 ret = btrfs_find_last_root(tree_root, objectid,
807 &root->root_item, &root->root_key);
808 BUG_ON(ret);
809
810 blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
811 root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
812 blocksize, 0);
813 BUG_ON(!root->node);
814 return 0;
815 }
816
817 int btrfs_free_log_root_tree(struct btrfs_trans_handle *trans,
818 struct btrfs_fs_info *fs_info)
819 {
820 struct extent_buffer *eb;
821 int ret;
822
823 if (!fs_info->log_root_tree)
824 return 0;
825
826 eb = fs_info->log_root_tree->node;
827
828 WARN_ON(btrfs_header_level(eb) != 0);
829 WARN_ON(btrfs_header_nritems(eb) != 0);
830
831 ret = btrfs_free_extent(trans, fs_info->tree_root,
832 eb->start, eb->len,
833 BTRFS_TREE_LOG_OBJECTID, 0, 0, 0, 1);
834 BUG_ON(ret);
835
836 free_extent_buffer(eb);
837 kfree(fs_info->log_root_tree);
838 fs_info->log_root_tree = NULL;
839 return 0;
840 }
841
842 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
843 struct btrfs_fs_info *fs_info)
844 {
845 struct btrfs_root *root;
846 struct btrfs_root *tree_root = fs_info->tree_root;
847
848 root = kzalloc(sizeof(*root), GFP_NOFS);
849 if (!root)
850 return -ENOMEM;
851
852 __setup_root(tree_root->nodesize, tree_root->leafsize,
853 tree_root->sectorsize, tree_root->stripesize,
854 root, fs_info, BTRFS_TREE_LOG_OBJECTID);
855
856 root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
857 root->root_key.type = BTRFS_ROOT_ITEM_KEY;
858 root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
859 root->ref_cows = 0;
860
861 root->node = btrfs_alloc_free_block(trans, root, root->leafsize,
862 BTRFS_TREE_LOG_OBJECTID,
863 0, 0, 0, 0, 0);
864
865 btrfs_set_header_nritems(root->node, 0);
866 btrfs_set_header_level(root->node, 0);
867 btrfs_set_header_bytenr(root->node, root->node->start);
868 btrfs_set_header_generation(root->node, trans->transid);
869 btrfs_set_header_owner(root->node, BTRFS_TREE_LOG_OBJECTID);
870
871 write_extent_buffer(root->node, root->fs_info->fsid,
872 (unsigned long)btrfs_header_fsid(root->node),
873 BTRFS_FSID_SIZE);
874 btrfs_mark_buffer_dirty(root->node);
875 btrfs_tree_unlock(root->node);
876 fs_info->log_root_tree = root;
877 return 0;
878 }
879
880 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
881 struct btrfs_key *location)
882 {
883 struct btrfs_root *root;
884 struct btrfs_fs_info *fs_info = tree_root->fs_info;
885 struct btrfs_path *path;
886 struct extent_buffer *l;
887 u64 highest_inode;
888 u32 blocksize;
889 int ret = 0;
890
891 root = kzalloc(sizeof(*root), GFP_NOFS);
892 if (!root)
893 return ERR_PTR(-ENOMEM);
894 if (location->offset == (u64)-1) {
895 ret = find_and_setup_root(tree_root, fs_info,
896 location->objectid, root);
897 if (ret) {
898 kfree(root);
899 return ERR_PTR(ret);
900 }
901 goto insert;
902 }
903
904 __setup_root(tree_root->nodesize, tree_root->leafsize,
905 tree_root->sectorsize, tree_root->stripesize,
906 root, fs_info, location->objectid);
907
908 path = btrfs_alloc_path();
909 BUG_ON(!path);
910 ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
911 if (ret != 0) {
912 if (ret > 0)
913 ret = -ENOENT;
914 goto out;
915 }
916 l = path->nodes[0];
917 read_extent_buffer(l, &root->root_item,
918 btrfs_item_ptr_offset(l, path->slots[0]),
919 sizeof(root->root_item));
920 memcpy(&root->root_key, location, sizeof(*location));
921 ret = 0;
922 out:
923 btrfs_release_path(root, path);
924 btrfs_free_path(path);
925 if (ret) {
926 kfree(root);
927 return ERR_PTR(ret);
928 }
929 blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
930 root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
931 blocksize, 0);
932 BUG_ON(!root->node);
933 insert:
934 if (location->objectid != BTRFS_TREE_LOG_OBJECTID) {
935 root->ref_cows = 1;
936 ret = btrfs_find_highest_inode(root, &highest_inode);
937 if (ret == 0) {
938 root->highest_inode = highest_inode;
939 root->last_inode_alloc = highest_inode;
940 }
941 }
942 return root;
943 }
944
945 struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
946 u64 root_objectid)
947 {
948 struct btrfs_root *root;
949
950 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID)
951 return fs_info->tree_root;
952 if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID)
953 return fs_info->extent_root;
954
955 root = radix_tree_lookup(&fs_info->fs_roots_radix,
956 (unsigned long)root_objectid);
957 return root;
958 }
959
960 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
961 struct btrfs_key *location)
962 {
963 struct btrfs_root *root;
964 int ret;
965
966 if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
967 return fs_info->tree_root;
968 if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
969 return fs_info->extent_root;
970 if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
971 return fs_info->chunk_root;
972 if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
973 return fs_info->dev_root;
974
975 root = radix_tree_lookup(&fs_info->fs_roots_radix,
976 (unsigned long)location->objectid);
977 if (root)
978 return root;
979
980 root = btrfs_read_fs_root_no_radix(fs_info->tree_root, location);
981 if (IS_ERR(root))
982 return root;
983 ret = radix_tree_insert(&fs_info->fs_roots_radix,
984 (unsigned long)root->root_key.objectid,
985 root);
986 if (ret) {
987 free_extent_buffer(root->node);
988 kfree(root);
989 return ERR_PTR(ret);
990 }
991 ret = btrfs_find_dead_roots(fs_info->tree_root,
992 root->root_key.objectid, root);
993 BUG_ON(ret);
994
995 return root;
996 }
997
998 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
999 struct btrfs_key *location,
1000 const char *name, int namelen)
1001 {
1002 struct btrfs_root *root;
1003 int ret;
1004
1005 root = btrfs_read_fs_root_no_name(fs_info, location);
1006 if (!root)
1007 return NULL;
1008
1009 if (root->in_sysfs)
1010 return root;
1011
1012 ret = btrfs_set_root_name(root, name, namelen);
1013 if (ret) {
1014 free_extent_buffer(root->node);
1015 kfree(root);
1016 return ERR_PTR(ret);
1017 }
1018
1019 ret = btrfs_sysfs_add_root(root);
1020 if (ret) {
1021 free_extent_buffer(root->node);
1022 kfree(root->name);
1023 kfree(root);
1024 return ERR_PTR(ret);
1025 }
1026 root->in_sysfs = 1;
1027 return root;
1028 }
1029 #if 0
1030 static int add_hasher(struct btrfs_fs_info *info, char *type) {
1031 struct btrfs_hasher *hasher;
1032
1033 hasher = kmalloc(sizeof(*hasher), GFP_NOFS);
1034 if (!hasher)
1035 return -ENOMEM;
1036 hasher->hash_tfm = crypto_alloc_hash(type, 0, CRYPTO_ALG_ASYNC);
1037 if (!hasher->hash_tfm) {
1038 kfree(hasher);
1039 return -EINVAL;
1040 }
1041 spin_lock(&info->hash_lock);
1042 list_add(&hasher->list, &info->hashers);
1043 spin_unlock(&info->hash_lock);
1044 return 0;
1045 }
1046 #endif
1047
1048 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1049 {
1050 struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1051 int ret = 0;
1052 struct list_head *cur;
1053 struct btrfs_device *device;
1054 struct backing_dev_info *bdi;
1055
1056 if ((bdi_bits & (1 << BDI_write_congested)) &&
1057 btrfs_congested_async(info, 0))
1058 return 1;
1059
1060 list_for_each(cur, &info->fs_devices->devices) {
1061 device = list_entry(cur, struct btrfs_device, dev_list);
1062 if (!device->bdev)
1063 continue;
1064 bdi = blk_get_backing_dev_info(device->bdev);
1065 if (bdi && bdi_congested(bdi, bdi_bits)) {
1066 ret = 1;
1067 break;
1068 }
1069 }
1070 return ret;
1071 }
1072
1073 /*
1074 * this unplugs every device on the box, and it is only used when page
1075 * is null
1076 */
1077 static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1078 {
1079 struct list_head *cur;
1080 struct btrfs_device *device;
1081 struct btrfs_fs_info *info;
1082
1083 info = (struct btrfs_fs_info *)bdi->unplug_io_data;
1084 list_for_each(cur, &info->fs_devices->devices) {
1085 device = list_entry(cur, struct btrfs_device, dev_list);
1086 bdi = blk_get_backing_dev_info(device->bdev);
1087 if (bdi->unplug_io_fn) {
1088 bdi->unplug_io_fn(bdi, page);
1089 }
1090 }
1091 }
1092
1093 void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1094 {
1095 struct inode *inode;
1096 struct extent_map_tree *em_tree;
1097 struct extent_map *em;
1098 struct address_space *mapping;
1099 u64 offset;
1100
1101 /* the generic O_DIRECT read code does this */
1102 if (!page) {
1103 __unplug_io_fn(bdi, page);
1104 return;
1105 }
1106
1107 /*
1108 * page->mapping may change at any time. Get a consistent copy
1109 * and use that for everything below
1110 */
1111 smp_mb();
1112 mapping = page->mapping;
1113 if (!mapping)
1114 return;
1115
1116 inode = mapping->host;
1117 offset = page_offset(page);
1118
1119 em_tree = &BTRFS_I(inode)->extent_tree;
1120 spin_lock(&em_tree->lock);
1121 em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
1122 spin_unlock(&em_tree->lock);
1123 if (!em) {
1124 __unplug_io_fn(bdi, page);
1125 return;
1126 }
1127
1128 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1129 free_extent_map(em);
1130 __unplug_io_fn(bdi, page);
1131 return;
1132 }
1133 offset = offset - em->start;
1134 btrfs_unplug_page(&BTRFS_I(inode)->root->fs_info->mapping_tree,
1135 em->block_start + offset, page);
1136 free_extent_map(em);
1137 }
1138
1139 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1140 {
1141 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1142 bdi_init(bdi);
1143 #endif
1144 bdi->ra_pages = default_backing_dev_info.ra_pages;
1145 bdi->state = 0;
1146 bdi->capabilities = default_backing_dev_info.capabilities;
1147 bdi->unplug_io_fn = btrfs_unplug_io_fn;
1148 bdi->unplug_io_data = info;
1149 bdi->congested_fn = btrfs_congested_fn;
1150 bdi->congested_data = info;
1151 return 0;
1152 }
1153
1154 static int bio_ready_for_csum(struct bio *bio)
1155 {
1156 u64 length = 0;
1157 u64 buf_len = 0;
1158 u64 start = 0;
1159 struct page *page;
1160 struct extent_io_tree *io_tree = NULL;
1161 struct btrfs_fs_info *info = NULL;
1162 struct bio_vec *bvec;
1163 int i;
1164 int ret;
1165
1166 bio_for_each_segment(bvec, bio, i) {
1167 page = bvec->bv_page;
1168 if (page->private == EXTENT_PAGE_PRIVATE) {
1169 length += bvec->bv_len;
1170 continue;
1171 }
1172 if (!page->private) {
1173 length += bvec->bv_len;
1174 continue;
1175 }
1176 length = bvec->bv_len;
1177 buf_len = page->private >> 2;
1178 start = page_offset(page) + bvec->bv_offset;
1179 io_tree = &BTRFS_I(page->mapping->host)->io_tree;
1180 info = BTRFS_I(page->mapping->host)->root->fs_info;
1181 }
1182 /* are we fully contained in this bio? */
1183 if (buf_len <= length)
1184 return 1;
1185
1186 ret = extent_range_uptodate(io_tree, start + length,
1187 start + buf_len - 1);
1188 if (ret == 1)
1189 return ret;
1190 return ret;
1191 }
1192
1193 /*
1194 * called by the kthread helper functions to finally call the bio end_io
1195 * functions. This is where read checksum verification actually happens
1196 */
1197 static void end_workqueue_fn(struct btrfs_work *work)
1198 {
1199 struct bio *bio;
1200 struct end_io_wq *end_io_wq;
1201 struct btrfs_fs_info *fs_info;
1202 int error;
1203
1204 end_io_wq = container_of(work, struct end_io_wq, work);
1205 bio = end_io_wq->bio;
1206 fs_info = end_io_wq->info;
1207
1208 /* metadata bios are special because the whole tree block must
1209 * be checksummed at once. This makes sure the entire block is in
1210 * ram and up to date before trying to verify things. For
1211 * blocksize <= pagesize, it is basically a noop
1212 */
1213 if (end_io_wq->metadata && !bio_ready_for_csum(bio)) {
1214 btrfs_queue_worker(&fs_info->endio_workers,
1215 &end_io_wq->work);
1216 return;
1217 }
1218 error = end_io_wq->error;
1219 bio->bi_private = end_io_wq->private;
1220 bio->bi_end_io = end_io_wq->end_io;
1221 kfree(end_io_wq);
1222 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1223 bio_endio(bio, bio->bi_size, error);
1224 #else
1225 bio_endio(bio, error);
1226 #endif
1227 }
1228
1229 static int cleaner_kthread(void *arg)
1230 {
1231 struct btrfs_root *root = arg;
1232
1233 do {
1234 smp_mb();
1235 if (root->fs_info->closing)
1236 break;
1237
1238 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1239 mutex_lock(&root->fs_info->cleaner_mutex);
1240 btrfs_clean_old_snapshots(root);
1241 mutex_unlock(&root->fs_info->cleaner_mutex);
1242
1243 if (freezing(current)) {
1244 refrigerator();
1245 } else {
1246 smp_mb();
1247 if (root->fs_info->closing)
1248 break;
1249 set_current_state(TASK_INTERRUPTIBLE);
1250 schedule();
1251 __set_current_state(TASK_RUNNING);
1252 }
1253 } while (!kthread_should_stop());
1254 return 0;
1255 }
1256
1257 static int transaction_kthread(void *arg)
1258 {
1259 struct btrfs_root *root = arg;
1260 struct btrfs_trans_handle *trans;
1261 struct btrfs_transaction *cur;
1262 unsigned long now;
1263 unsigned long delay;
1264 int ret;
1265
1266 do {
1267 smp_mb();
1268 if (root->fs_info->closing)
1269 break;
1270
1271 delay = HZ * 30;
1272 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1273 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1274
1275 if (root->fs_info->total_ref_cache_size > 20 * 1024 * 1024) {
1276 printk("btrfs: total reference cache size %Lu\n",
1277 root->fs_info->total_ref_cache_size);
1278 }
1279
1280 mutex_lock(&root->fs_info->trans_mutex);
1281 cur = root->fs_info->running_transaction;
1282 if (!cur) {
1283 mutex_unlock(&root->fs_info->trans_mutex);
1284 goto sleep;
1285 }
1286
1287 now = get_seconds();
1288 if (now < cur->start_time || now - cur->start_time < 30) {
1289 mutex_unlock(&root->fs_info->trans_mutex);
1290 delay = HZ * 5;
1291 goto sleep;
1292 }
1293 mutex_unlock(&root->fs_info->trans_mutex);
1294 trans = btrfs_start_transaction(root, 1);
1295 ret = btrfs_commit_transaction(trans, root);
1296 sleep:
1297 wake_up_process(root->fs_info->cleaner_kthread);
1298 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1299
1300 if (freezing(current)) {
1301 refrigerator();
1302 } else {
1303 if (root->fs_info->closing)
1304 break;
1305 set_current_state(TASK_INTERRUPTIBLE);
1306 schedule_timeout(delay);
1307 __set_current_state(TASK_RUNNING);
1308 }
1309 } while (!kthread_should_stop());
1310 return 0;
1311 }
1312
1313 struct btrfs_root *open_ctree(struct super_block *sb,
1314 struct btrfs_fs_devices *fs_devices,
1315 char *options)
1316 {
1317 u32 sectorsize;
1318 u32 nodesize;
1319 u32 leafsize;
1320 u32 blocksize;
1321 u32 stripesize;
1322 struct buffer_head *bh;
1323 struct btrfs_root *extent_root = kzalloc(sizeof(struct btrfs_root),
1324 GFP_NOFS);
1325 struct btrfs_root *tree_root = kzalloc(sizeof(struct btrfs_root),
1326 GFP_NOFS);
1327 struct btrfs_fs_info *fs_info = kzalloc(sizeof(*fs_info),
1328 GFP_NOFS);
1329 struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root),
1330 GFP_NOFS);
1331 struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root),
1332 GFP_NOFS);
1333 struct btrfs_root *log_tree_root;
1334
1335 int ret;
1336 int err = -EINVAL;
1337
1338 struct btrfs_super_block *disk_super;
1339
1340 if (!extent_root || !tree_root || !fs_info) {
1341 err = -ENOMEM;
1342 goto fail;
1343 }
1344 INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
1345 INIT_LIST_HEAD(&fs_info->trans_list);
1346 INIT_LIST_HEAD(&fs_info->dead_roots);
1347 INIT_LIST_HEAD(&fs_info->hashers);
1348 INIT_LIST_HEAD(&fs_info->delalloc_inodes);
1349 spin_lock_init(&fs_info->hash_lock);
1350 spin_lock_init(&fs_info->delalloc_lock);
1351 spin_lock_init(&fs_info->new_trans_lock);
1352 spin_lock_init(&fs_info->ref_cache_lock);
1353
1354 init_completion(&fs_info->kobj_unregister);
1355 fs_info->tree_root = tree_root;
1356 fs_info->extent_root = extent_root;
1357 fs_info->chunk_root = chunk_root;
1358 fs_info->dev_root = dev_root;
1359 fs_info->fs_devices = fs_devices;
1360 INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
1361 INIT_LIST_HEAD(&fs_info->space_info);
1362 btrfs_mapping_init(&fs_info->mapping_tree);
1363 atomic_set(&fs_info->nr_async_submits, 0);
1364 atomic_set(&fs_info->nr_async_bios, 0);
1365 atomic_set(&fs_info->throttles, 0);
1366 atomic_set(&fs_info->throttle_gen, 0);
1367 fs_info->sb = sb;
1368 fs_info->max_extent = (u64)-1;
1369 fs_info->max_inline = 8192 * 1024;
1370 setup_bdi(fs_info, &fs_info->bdi);
1371 fs_info->btree_inode = new_inode(sb);
1372 fs_info->btree_inode->i_ino = 1;
1373 fs_info->btree_inode->i_nlink = 1;
1374 fs_info->thread_pool_size = min(num_online_cpus() + 2, 8);
1375
1376 INIT_LIST_HEAD(&fs_info->ordered_extents);
1377 spin_lock_init(&fs_info->ordered_extent_lock);
1378
1379 sb->s_blocksize = 4096;
1380 sb->s_blocksize_bits = blksize_bits(4096);
1381
1382 /*
1383 * we set the i_size on the btree inode to the max possible int.
1384 * the real end of the address space is determined by all of
1385 * the devices in the system
1386 */
1387 fs_info->btree_inode->i_size = OFFSET_MAX;
1388 fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
1389 fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
1390
1391 extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
1392 fs_info->btree_inode->i_mapping,
1393 GFP_NOFS);
1394 extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree,
1395 GFP_NOFS);
1396
1397 BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
1398
1399 extent_io_tree_init(&fs_info->free_space_cache,
1400 fs_info->btree_inode->i_mapping, GFP_NOFS);
1401 extent_io_tree_init(&fs_info->block_group_cache,
1402 fs_info->btree_inode->i_mapping, GFP_NOFS);
1403 extent_io_tree_init(&fs_info->pinned_extents,
1404 fs_info->btree_inode->i_mapping, GFP_NOFS);
1405 extent_io_tree_init(&fs_info->pending_del,
1406 fs_info->btree_inode->i_mapping, GFP_NOFS);
1407 extent_io_tree_init(&fs_info->extent_ins,
1408 fs_info->btree_inode->i_mapping, GFP_NOFS);
1409 fs_info->do_barriers = 1;
1410
1411 BTRFS_I(fs_info->btree_inode)->root = tree_root;
1412 memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
1413 sizeof(struct btrfs_key));
1414 insert_inode_hash(fs_info->btree_inode);
1415 mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
1416
1417 mutex_init(&fs_info->trans_mutex);
1418 mutex_init(&fs_info->tree_log_mutex);
1419 mutex_init(&fs_info->drop_mutex);
1420 mutex_init(&fs_info->alloc_mutex);
1421 mutex_init(&fs_info->chunk_mutex);
1422 mutex_init(&fs_info->transaction_kthread_mutex);
1423 mutex_init(&fs_info->cleaner_mutex);
1424 mutex_init(&fs_info->volume_mutex);
1425 init_waitqueue_head(&fs_info->transaction_throttle);
1426 init_waitqueue_head(&fs_info->transaction_wait);
1427 init_waitqueue_head(&fs_info->async_submit_wait);
1428 init_waitqueue_head(&fs_info->tree_log_wait);
1429 atomic_set(&fs_info->tree_log_commit, 0);
1430 atomic_set(&fs_info->tree_log_writers, 0);
1431 fs_info->tree_log_transid = 0;
1432
1433 #if 0
1434 ret = add_hasher(fs_info, "crc32c");
1435 if (ret) {
1436 printk("btrfs: failed hash setup, modprobe cryptomgr?\n");
1437 err = -ENOMEM;
1438 goto fail_iput;
1439 }
1440 #endif
1441 __setup_root(4096, 4096, 4096, 4096, tree_root,
1442 fs_info, BTRFS_ROOT_TREE_OBJECTID);
1443
1444
1445 bh = __bread(fs_devices->latest_bdev,
1446 BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
1447 if (!bh)
1448 goto fail_iput;
1449
1450 memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));
1451 brelse(bh);
1452
1453 memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
1454
1455 disk_super = &fs_info->super_copy;
1456 if (!btrfs_super_root(disk_super))
1457 goto fail_sb_buffer;
1458
1459 err = btrfs_parse_options(tree_root, options);
1460 if (err)
1461 goto fail_sb_buffer;
1462
1463 /*
1464 * we need to start all the end_io workers up front because the
1465 * queue work function gets called at interrupt time, and so it
1466 * cannot dynamically grow.
1467 */
1468 btrfs_init_workers(&fs_info->workers, "worker",
1469 fs_info->thread_pool_size);
1470 btrfs_init_workers(&fs_info->submit_workers, "submit",
1471 min_t(u64, fs_devices->num_devices,
1472 fs_info->thread_pool_size));
1473
1474 /* a higher idle thresh on the submit workers makes it much more
1475 * likely that bios will be send down in a sane order to the
1476 * devices
1477 */
1478 fs_info->submit_workers.idle_thresh = 64;
1479
1480 /* fs_info->workers is responsible for checksumming file data
1481 * blocks and metadata. Using a larger idle thresh allows each
1482 * worker thread to operate on things in roughly the order they
1483 * were sent by the writeback daemons, improving overall locality
1484 * of the IO going down the pipe.
1485 */
1486 fs_info->workers.idle_thresh = 128;
1487
1488 btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1);
1489 btrfs_init_workers(&fs_info->endio_workers, "endio",
1490 fs_info->thread_pool_size);
1491 btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
1492 fs_info->thread_pool_size);
1493
1494 /*
1495 * endios are largely parallel and should have a very
1496 * low idle thresh
1497 */
1498 fs_info->endio_workers.idle_thresh = 4;
1499 fs_info->endio_write_workers.idle_thresh = 4;
1500
1501 btrfs_start_workers(&fs_info->workers, 1);
1502 btrfs_start_workers(&fs_info->submit_workers, 1);
1503 btrfs_start_workers(&fs_info->fixup_workers, 1);
1504 btrfs_start_workers(&fs_info->endio_workers, fs_info->thread_pool_size);
1505 btrfs_start_workers(&fs_info->endio_write_workers,
1506 fs_info->thread_pool_size);
1507
1508 err = -EINVAL;
1509 if (btrfs_super_num_devices(disk_super) > fs_devices->open_devices) {
1510 printk("Btrfs: wanted %llu devices, but found %llu\n",
1511 (unsigned long long)btrfs_super_num_devices(disk_super),
1512 (unsigned long long)fs_devices->open_devices);
1513 if (btrfs_test_opt(tree_root, DEGRADED))
1514 printk("continuing in degraded mode\n");
1515 else {
1516 goto fail_sb_buffer;
1517 }
1518 }
1519
1520 fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
1521
1522 nodesize = btrfs_super_nodesize(disk_super);
1523 leafsize = btrfs_super_leafsize(disk_super);
1524 sectorsize = btrfs_super_sectorsize(disk_super);
1525 stripesize = btrfs_super_stripesize(disk_super);
1526 tree_root->nodesize = nodesize;
1527 tree_root->leafsize = leafsize;
1528 tree_root->sectorsize = sectorsize;
1529 tree_root->stripesize = stripesize;
1530
1531 sb->s_blocksize = sectorsize;
1532 sb->s_blocksize_bits = blksize_bits(sectorsize);
1533
1534 if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
1535 sizeof(disk_super->magic))) {
1536 printk("btrfs: valid FS not found on %s\n", sb->s_id);
1537 goto fail_sb_buffer;
1538 }
1539
1540 mutex_lock(&fs_info->chunk_mutex);
1541 ret = btrfs_read_sys_array(tree_root);
1542 mutex_unlock(&fs_info->chunk_mutex);
1543 if (ret) {
1544 printk("btrfs: failed to read the system array on %s\n",
1545 sb->s_id);
1546 goto fail_sys_array;
1547 }
1548
1549 blocksize = btrfs_level_size(tree_root,
1550 btrfs_super_chunk_root_level(disk_super));
1551
1552 __setup_root(nodesize, leafsize, sectorsize, stripesize,
1553 chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
1554
1555 chunk_root->node = read_tree_block(chunk_root,
1556 btrfs_super_chunk_root(disk_super),
1557 blocksize, 0);
1558 BUG_ON(!chunk_root->node);
1559
1560 read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
1561 (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
1562 BTRFS_UUID_SIZE);
1563
1564 mutex_lock(&fs_info->chunk_mutex);
1565 ret = btrfs_read_chunk_tree(chunk_root);
1566 mutex_unlock(&fs_info->chunk_mutex);
1567 BUG_ON(ret);
1568
1569 btrfs_close_extra_devices(fs_devices);
1570
1571 blocksize = btrfs_level_size(tree_root,
1572 btrfs_super_root_level(disk_super));
1573
1574
1575 tree_root->node = read_tree_block(tree_root,
1576 btrfs_super_root(disk_super),
1577 blocksize, 0);
1578 if (!tree_root->node)
1579 goto fail_sb_buffer;
1580
1581
1582 ret = find_and_setup_root(tree_root, fs_info,
1583 BTRFS_EXTENT_TREE_OBJECTID, extent_root);
1584 if (ret)
1585 goto fail_tree_root;
1586 extent_root->track_dirty = 1;
1587
1588 ret = find_and_setup_root(tree_root, fs_info,
1589 BTRFS_DEV_TREE_OBJECTID, dev_root);
1590 dev_root->track_dirty = 1;
1591
1592 if (ret)
1593 goto fail_extent_root;
1594
1595 btrfs_read_block_groups(extent_root);
1596
1597 fs_info->generation = btrfs_super_generation(disk_super) + 1;
1598 fs_info->data_alloc_profile = (u64)-1;
1599 fs_info->metadata_alloc_profile = (u64)-1;
1600 fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
1601 fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
1602 "btrfs-cleaner");
1603 if (!fs_info->cleaner_kthread)
1604 goto fail_extent_root;
1605
1606 fs_info->transaction_kthread = kthread_run(transaction_kthread,
1607 tree_root,
1608 "btrfs-transaction");
1609 if (!fs_info->transaction_kthread)
1610 goto fail_cleaner;
1611
1612 if (btrfs_super_log_root(disk_super) != 0) {
1613 u32 blocksize;
1614 u64 bytenr = btrfs_super_log_root(disk_super);
1615
1616 blocksize =
1617 btrfs_level_size(tree_root,
1618 btrfs_super_log_root_level(disk_super));
1619
1620 log_tree_root = kzalloc(sizeof(struct btrfs_root),
1621 GFP_NOFS);
1622
1623 __setup_root(nodesize, leafsize, sectorsize, stripesize,
1624 log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1625
1626 log_tree_root->node = read_tree_block(tree_root, bytenr,
1627 blocksize, 0);
1628 ret = btrfs_recover_log_trees(log_tree_root);
1629 BUG_ON(ret);
1630 }
1631 fs_info->last_trans_committed = btrfs_super_generation(disk_super);
1632 return tree_root;
1633
1634 fail_cleaner:
1635 kthread_stop(fs_info->cleaner_kthread);
1636 fail_extent_root:
1637 free_extent_buffer(extent_root->node);
1638 fail_tree_root:
1639 free_extent_buffer(tree_root->node);
1640 fail_sys_array:
1641 fail_sb_buffer:
1642 btrfs_stop_workers(&fs_info->fixup_workers);
1643 btrfs_stop_workers(&fs_info->workers);
1644 btrfs_stop_workers(&fs_info->endio_workers);
1645 btrfs_stop_workers(&fs_info->endio_write_workers);
1646 btrfs_stop_workers(&fs_info->submit_workers);
1647 fail_iput:
1648 iput(fs_info->btree_inode);
1649 fail:
1650 btrfs_close_devices(fs_info->fs_devices);
1651 btrfs_mapping_tree_free(&fs_info->mapping_tree);
1652
1653 kfree(extent_root);
1654 kfree(tree_root);
1655 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1656 bdi_destroy(&fs_info->bdi);
1657 #endif
1658 kfree(fs_info);
1659 return ERR_PTR(err);
1660 }
1661
1662 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
1663 {
1664 char b[BDEVNAME_SIZE];
1665
1666 if (uptodate) {
1667 set_buffer_uptodate(bh);
1668 } else {
1669 if (!buffer_eopnotsupp(bh) && printk_ratelimit()) {
1670 printk(KERN_WARNING "lost page write due to "
1671 "I/O error on %s\n",
1672 bdevname(bh->b_bdev, b));
1673 }
1674 /* note, we dont' set_buffer_write_io_error because we have
1675 * our own ways of dealing with the IO errors
1676 */
1677 clear_buffer_uptodate(bh);
1678 }
1679 unlock_buffer(bh);
1680 put_bh(bh);
1681 }
1682
1683 int write_all_supers(struct btrfs_root *root)
1684 {
1685 struct list_head *cur;
1686 struct list_head *head = &root->fs_info->fs_devices->devices;
1687 struct btrfs_device *dev;
1688 struct btrfs_super_block *sb;
1689 struct btrfs_dev_item *dev_item;
1690 struct buffer_head *bh;
1691 int ret;
1692 int do_barriers;
1693 int max_errors;
1694 int total_errors = 0;
1695 u32 crc;
1696 u64 flags;
1697
1698 max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
1699 do_barriers = !btrfs_test_opt(root, NOBARRIER);
1700
1701 sb = &root->fs_info->super_for_commit;
1702 dev_item = &sb->dev_item;
1703 list_for_each(cur, head) {
1704 dev = list_entry(cur, struct btrfs_device, dev_list);
1705 if (!dev->bdev) {
1706 total_errors++;
1707 continue;
1708 }
1709 if (!dev->in_fs_metadata)
1710 continue;
1711
1712 btrfs_set_stack_device_type(dev_item, dev->type);
1713 btrfs_set_stack_device_id(dev_item, dev->devid);
1714 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
1715 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
1716 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
1717 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
1718 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
1719 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
1720 flags = btrfs_super_flags(sb);
1721 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
1722
1723
1724 crc = ~(u32)0;
1725 crc = btrfs_csum_data(root, (char *)sb + BTRFS_CSUM_SIZE, crc,
1726 BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
1727 btrfs_csum_final(crc, sb->csum);
1728
1729 bh = __getblk(dev->bdev, BTRFS_SUPER_INFO_OFFSET / 4096,
1730 BTRFS_SUPER_INFO_SIZE);
1731
1732 memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
1733 dev->pending_io = bh;
1734
1735 get_bh(bh);
1736 set_buffer_uptodate(bh);
1737 lock_buffer(bh);
1738 bh->b_end_io = btrfs_end_buffer_write_sync;
1739
1740 if (do_barriers && dev->barriers) {
1741 ret = submit_bh(WRITE_BARRIER, bh);
1742 if (ret == -EOPNOTSUPP) {
1743 printk("btrfs: disabling barriers on dev %s\n",
1744 dev->name);
1745 set_buffer_uptodate(bh);
1746 dev->barriers = 0;
1747 get_bh(bh);
1748 lock_buffer(bh);
1749 ret = submit_bh(WRITE, bh);
1750 }
1751 } else {
1752 ret = submit_bh(WRITE, bh);
1753 }
1754 if (ret)
1755 total_errors++;
1756 }
1757 if (total_errors > max_errors) {
1758 printk("btrfs: %d errors while writing supers\n", total_errors);
1759 BUG();
1760 }
1761 total_errors = 0;
1762
1763 list_for_each(cur, head) {
1764 dev = list_entry(cur, struct btrfs_device, dev_list);
1765 if (!dev->bdev)
1766 continue;
1767 if (!dev->in_fs_metadata)
1768 continue;
1769
1770 BUG_ON(!dev->pending_io);
1771 bh = dev->pending_io;
1772 wait_on_buffer(bh);
1773 if (!buffer_uptodate(dev->pending_io)) {
1774 if (do_barriers && dev->barriers) {
1775 printk("btrfs: disabling barriers on dev %s\n",
1776 dev->name);
1777 set_buffer_uptodate(bh);
1778 get_bh(bh);
1779 lock_buffer(bh);
1780 dev->barriers = 0;
1781 ret = submit_bh(WRITE, bh);
1782 BUG_ON(ret);
1783 wait_on_buffer(bh);
1784 if (!buffer_uptodate(bh))
1785 total_errors++;
1786 } else {
1787 total_errors++;
1788 }
1789
1790 }
1791 dev->pending_io = NULL;
1792 brelse(bh);
1793 }
1794 if (total_errors > max_errors) {
1795 printk("btrfs: %d errors while writing supers\n", total_errors);
1796 BUG();
1797 }
1798 return 0;
1799 }
1800
1801 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
1802 *root)
1803 {
1804 int ret;
1805
1806 ret = write_all_supers(root);
1807 return ret;
1808 }
1809
1810 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
1811 {
1812 radix_tree_delete(&fs_info->fs_roots_radix,
1813 (unsigned long)root->root_key.objectid);
1814 if (root->in_sysfs)
1815 btrfs_sysfs_del_root(root);
1816 if (root->inode)
1817 iput(root->inode);
1818 if (root->node)
1819 free_extent_buffer(root->node);
1820 if (root->commit_root)
1821 free_extent_buffer(root->commit_root);
1822 if (root->name)
1823 kfree(root->name);
1824 kfree(root);
1825 return 0;
1826 }
1827
1828 static int del_fs_roots(struct btrfs_fs_info *fs_info)
1829 {
1830 int ret;
1831 struct btrfs_root *gang[8];
1832 int i;
1833
1834 while(1) {
1835 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
1836 (void **)gang, 0,
1837 ARRAY_SIZE(gang));
1838 if (!ret)
1839 break;
1840 for (i = 0; i < ret; i++)
1841 btrfs_free_fs_root(fs_info, gang[i]);
1842 }
1843 return 0;
1844 }
1845
1846 int close_ctree(struct btrfs_root *root)
1847 {
1848 int ret;
1849 struct btrfs_trans_handle *trans;
1850 struct btrfs_fs_info *fs_info = root->fs_info;
1851
1852 fs_info->closing = 1;
1853 smp_mb();
1854
1855 kthread_stop(root->fs_info->transaction_kthread);
1856 kthread_stop(root->fs_info->cleaner_kthread);
1857
1858 btrfs_clean_old_snapshots(root);
1859 trans = btrfs_start_transaction(root, 1);
1860 ret = btrfs_commit_transaction(trans, root);
1861 /* run commit again to drop the original snapshot */
1862 trans = btrfs_start_transaction(root, 1);
1863 btrfs_commit_transaction(trans, root);
1864 ret = btrfs_write_and_wait_transaction(NULL, root);
1865 BUG_ON(ret);
1866
1867 write_ctree_super(NULL, root);
1868
1869 if (fs_info->delalloc_bytes) {
1870 printk("btrfs: at unmount delalloc count %Lu\n",
1871 fs_info->delalloc_bytes);
1872 }
1873 if (fs_info->total_ref_cache_size) {
1874 printk("btrfs: at umount reference cache size %Lu\n",
1875 fs_info->total_ref_cache_size);
1876 }
1877
1878 if (fs_info->extent_root->node)
1879 free_extent_buffer(fs_info->extent_root->node);
1880
1881 if (fs_info->tree_root->node)
1882 free_extent_buffer(fs_info->tree_root->node);
1883
1884 if (root->fs_info->chunk_root->node);
1885 free_extent_buffer(root->fs_info->chunk_root->node);
1886
1887 if (root->fs_info->dev_root->node);
1888 free_extent_buffer(root->fs_info->dev_root->node);
1889
1890 btrfs_free_block_groups(root->fs_info);
1891 fs_info->closing = 2;
1892 del_fs_roots(fs_info);
1893
1894 filemap_write_and_wait(fs_info->btree_inode->i_mapping);
1895
1896 truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
1897
1898 btrfs_stop_workers(&fs_info->fixup_workers);
1899 btrfs_stop_workers(&fs_info->workers);
1900 btrfs_stop_workers(&fs_info->endio_workers);
1901 btrfs_stop_workers(&fs_info->endio_write_workers);
1902 btrfs_stop_workers(&fs_info->submit_workers);
1903
1904 iput(fs_info->btree_inode);
1905 #if 0
1906 while(!list_empty(&fs_info->hashers)) {
1907 struct btrfs_hasher *hasher;
1908 hasher = list_entry(fs_info->hashers.next, struct btrfs_hasher,
1909 hashers);
1910 list_del(&hasher->hashers);
1911 crypto_free_hash(&fs_info->hash_tfm);
1912 kfree(hasher);
1913 }
1914 #endif
1915 btrfs_close_devices(fs_info->fs_devices);
1916 btrfs_mapping_tree_free(&fs_info->mapping_tree);
1917
1918 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1919 bdi_destroy(&fs_info->bdi);
1920 #endif
1921
1922 kfree(fs_info->extent_root);
1923 kfree(fs_info->tree_root);
1924 kfree(fs_info->chunk_root);
1925 kfree(fs_info->dev_root);
1926 return 0;
1927 }
1928
1929 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
1930 {
1931 int ret;
1932 struct inode *btree_inode = buf->first_page->mapping->host;
1933
1934 ret = extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf);
1935 if (!ret)
1936 return ret;
1937
1938 ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
1939 parent_transid);
1940 return !ret;
1941 }
1942
1943 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
1944 {
1945 struct inode *btree_inode = buf->first_page->mapping->host;
1946 return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
1947 buf);
1948 }
1949
1950 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
1951 {
1952 struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1953 u64 transid = btrfs_header_generation(buf);
1954 struct inode *btree_inode = root->fs_info->btree_inode;
1955
1956 WARN_ON(!btrfs_tree_locked(buf));
1957 if (transid != root->fs_info->generation) {
1958 printk(KERN_CRIT "transid mismatch buffer %llu, found %Lu running %Lu\n",
1959 (unsigned long long)buf->start,
1960 transid, root->fs_info->generation);
1961 WARN_ON(1);
1962 }
1963 set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree, buf);
1964 }
1965
1966 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
1967 {
1968 /*
1969 * looks as though older kernels can get into trouble with
1970 * this code, they end up stuck in balance_dirty_pages forever
1971 */
1972 struct extent_io_tree *tree;
1973 u64 num_dirty;
1974 u64 start = 0;
1975 unsigned long thresh = 96 * 1024 * 1024;
1976 tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
1977
1978 if (current_is_pdflush() || current->flags & PF_MEMALLOC)
1979 return;
1980
1981 num_dirty = count_range_bits(tree, &start, (u64)-1,
1982 thresh, EXTENT_DIRTY);
1983 if (num_dirty > thresh) {
1984 balance_dirty_pages_ratelimited_nr(
1985 root->fs_info->btree_inode->i_mapping, 1);
1986 }
1987 return;
1988 }
1989
1990 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
1991 {
1992 struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1993 int ret;
1994 ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
1995 if (ret == 0) {
1996 buf->flags |= EXTENT_UPTODATE;
1997 }
1998 return ret;
1999 }
2000
2001 static struct extent_io_ops btree_extent_io_ops = {
2002 .writepage_io_hook = btree_writepage_io_hook,
2003 .readpage_end_io_hook = btree_readpage_end_io_hook,
2004 .submit_bio_hook = btree_submit_bio_hook,
2005 /* note we're sharing with inode.c for the merge bio hook */
2006 .merge_bio_hook = btrfs_merge_bio_hook,
2007 };
Linux kernel - Deliverables
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