Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux...
[linux-2.6.git] / fs / btrfs / scrub.c
blob4f76fc3f8e896ed70b01bcb2f45bdbc68a583ba7
1 /*
2 * Copyright (C) 2011 STRATO. All rights reserved.
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.
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.
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.
19 #include <linux/blkdev.h>
20 #include <linux/ratelimit.h>
21 #include "ctree.h"
22 #include "volumes.h"
23 #include "disk-io.h"
24 #include "ordered-data.h"
25 #include "transaction.h"
26 #include "backref.h"
27 #include "extent_io.h"
28 #include "check-integrity.h"
31 * This is only the first step towards a full-features scrub. It reads all
32 * extent and super block and verifies the checksums. In case a bad checksum
33 * is found or the extent cannot be read, good data will be written back if
34 * any can be found.
36 * Future enhancements:
37 * - In case an unrepairable extent is encountered, track which files are
38 * affected and report them
39 * - track and record media errors, throw out bad devices
40 * - add a mode to also read unallocated space
43 struct scrub_block;
44 struct scrub_dev;
46 #define SCRUB_PAGES_PER_BIO 16 /* 64k per bio */
47 #define SCRUB_BIOS_PER_DEV 16 /* 1 MB per device in flight */
48 #define SCRUB_MAX_PAGES_PER_BLOCK 16 /* 64k per node/leaf/sector */
50 struct scrub_page {
51 struct scrub_block *sblock;
52 struct page *page;
53 struct block_device *bdev;
54 u64 flags; /* extent flags */
55 u64 generation;
56 u64 logical;
57 u64 physical;
58 struct {
59 unsigned int mirror_num:8;
60 unsigned int have_csum:1;
61 unsigned int io_error:1;
63 u8 csum[BTRFS_CSUM_SIZE];
66 struct scrub_bio {
67 int index;
68 struct scrub_dev *sdev;
69 struct bio *bio;
70 int err;
71 u64 logical;
72 u64 physical;
73 struct scrub_page *pagev[SCRUB_PAGES_PER_BIO];
74 int page_count;
75 int next_free;
76 struct btrfs_work work;
79 struct scrub_block {
80 struct scrub_page pagev[SCRUB_MAX_PAGES_PER_BLOCK];
81 int page_count;
82 atomic_t outstanding_pages;
83 atomic_t ref_count; /* free mem on transition to zero */
84 struct scrub_dev *sdev;
85 struct {
86 unsigned int header_error:1;
87 unsigned int checksum_error:1;
88 unsigned int no_io_error_seen:1;
92 struct scrub_dev {
93 struct scrub_bio *bios[SCRUB_BIOS_PER_DEV];
94 struct btrfs_device *dev;
95 int first_free;
96 int curr;
97 atomic_t in_flight;
98 atomic_t fixup_cnt;
99 spinlock_t list_lock;
100 wait_queue_head_t list_wait;
101 u16 csum_size;
102 struct list_head csum_list;
103 atomic_t cancel_req;
104 int readonly;
105 int pages_per_bio; /* <= SCRUB_PAGES_PER_BIO */
106 u32 sectorsize;
107 u32 nodesize;
108 u32 leafsize;
110 * statistics
112 struct btrfs_scrub_progress stat;
113 spinlock_t stat_lock;
116 struct scrub_fixup_nodatasum {
117 struct scrub_dev *sdev;
118 u64 logical;
119 struct btrfs_root *root;
120 struct btrfs_work work;
121 int mirror_num;
124 struct scrub_warning {
125 struct btrfs_path *path;
126 u64 extent_item_size;
127 char *scratch_buf;
128 char *msg_buf;
129 const char *errstr;
130 sector_t sector;
131 u64 logical;
132 struct btrfs_device *dev;
133 int msg_bufsize;
134 int scratch_bufsize;
138 static int scrub_handle_errored_block(struct scrub_block *sblock_to_check);
139 static int scrub_setup_recheck_block(struct scrub_dev *sdev,
140 struct btrfs_mapping_tree *map_tree,
141 u64 length, u64 logical,
142 struct scrub_block *sblock);
143 static int scrub_recheck_block(struct btrfs_fs_info *fs_info,
144 struct scrub_block *sblock, int is_metadata,
145 int have_csum, u8 *csum, u64 generation,
146 u16 csum_size);
147 static void scrub_recheck_block_checksum(struct btrfs_fs_info *fs_info,
148 struct scrub_block *sblock,
149 int is_metadata, int have_csum,
150 const u8 *csum, u64 generation,
151 u16 csum_size);
152 static void scrub_complete_bio_end_io(struct bio *bio, int err);
153 static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
154 struct scrub_block *sblock_good,
155 int force_write);
156 static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
157 struct scrub_block *sblock_good,
158 int page_num, int force_write);
159 static int scrub_checksum_data(struct scrub_block *sblock);
160 static int scrub_checksum_tree_block(struct scrub_block *sblock);
161 static int scrub_checksum_super(struct scrub_block *sblock);
162 static void scrub_block_get(struct scrub_block *sblock);
163 static void scrub_block_put(struct scrub_block *sblock);
164 static int scrub_add_page_to_bio(struct scrub_dev *sdev,
165 struct scrub_page *spage);
166 static int scrub_pages(struct scrub_dev *sdev, u64 logical, u64 len,
167 u64 physical, u64 flags, u64 gen, int mirror_num,
168 u8 *csum, int force);
169 static void scrub_bio_end_io(struct bio *bio, int err);
170 static void scrub_bio_end_io_worker(struct btrfs_work *work);
171 static void scrub_block_complete(struct scrub_block *sblock);
174 static void scrub_free_csums(struct scrub_dev *sdev)
176 while (!list_empty(&sdev->csum_list)) {
177 struct btrfs_ordered_sum *sum;
178 sum = list_first_entry(&sdev->csum_list,
179 struct btrfs_ordered_sum, list);
180 list_del(&sum->list);
181 kfree(sum);
185 static noinline_for_stack void scrub_free_dev(struct scrub_dev *sdev)
187 int i;
189 if (!sdev)
190 return;
192 /* this can happen when scrub is cancelled */
193 if (sdev->curr != -1) {
194 struct scrub_bio *sbio = sdev->bios[sdev->curr];
196 for (i = 0; i < sbio->page_count; i++) {
197 BUG_ON(!sbio->pagev[i]);
198 BUG_ON(!sbio->pagev[i]->page);
199 scrub_block_put(sbio->pagev[i]->sblock);
201 bio_put(sbio->bio);
204 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
205 struct scrub_bio *sbio = sdev->bios[i];
207 if (!sbio)
208 break;
209 kfree(sbio);
212 scrub_free_csums(sdev);
213 kfree(sdev);
216 static noinline_for_stack
217 struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
219 struct scrub_dev *sdev;
220 int i;
221 struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
222 int pages_per_bio;
224 pages_per_bio = min_t(int, SCRUB_PAGES_PER_BIO,
225 bio_get_nr_vecs(dev->bdev));
226 sdev = kzalloc(sizeof(*sdev), GFP_NOFS);
227 if (!sdev)
228 goto nomem;
229 sdev->dev = dev;
230 sdev->pages_per_bio = pages_per_bio;
231 sdev->curr = -1;
232 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
233 struct scrub_bio *sbio;
235 sbio = kzalloc(sizeof(*sbio), GFP_NOFS);
236 if (!sbio)
237 goto nomem;
238 sdev->bios[i] = sbio;
240 sbio->index = i;
241 sbio->sdev = sdev;
242 sbio->page_count = 0;
243 sbio->work.func = scrub_bio_end_io_worker;
245 if (i != SCRUB_BIOS_PER_DEV-1)
246 sdev->bios[i]->next_free = i + 1;
247 else
248 sdev->bios[i]->next_free = -1;
250 sdev->first_free = 0;
251 sdev->nodesize = dev->dev_root->nodesize;
252 sdev->leafsize = dev->dev_root->leafsize;
253 sdev->sectorsize = dev->dev_root->sectorsize;
254 atomic_set(&sdev->in_flight, 0);
255 atomic_set(&sdev->fixup_cnt, 0);
256 atomic_set(&sdev->cancel_req, 0);
257 sdev->csum_size = btrfs_super_csum_size(fs_info->super_copy);
258 INIT_LIST_HEAD(&sdev->csum_list);
260 spin_lock_init(&sdev->list_lock);
261 spin_lock_init(&sdev->stat_lock);
262 init_waitqueue_head(&sdev->list_wait);
263 return sdev;
265 nomem:
266 scrub_free_dev(sdev);
267 return ERR_PTR(-ENOMEM);
270 static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root, void *ctx)
272 u64 isize;
273 u32 nlink;
274 int ret;
275 int i;
276 struct extent_buffer *eb;
277 struct btrfs_inode_item *inode_item;
278 struct scrub_warning *swarn = ctx;
279 struct btrfs_fs_info *fs_info = swarn->dev->dev_root->fs_info;
280 struct inode_fs_paths *ipath = NULL;
281 struct btrfs_root *local_root;
282 struct btrfs_key root_key;
284 root_key.objectid = root;
285 root_key.type = BTRFS_ROOT_ITEM_KEY;
286 root_key.offset = (u64)-1;
287 local_root = btrfs_read_fs_root_no_name(fs_info, &root_key);
288 if (IS_ERR(local_root)) {
289 ret = PTR_ERR(local_root);
290 goto err;
293 ret = inode_item_info(inum, 0, local_root, swarn->path);
294 if (ret) {
295 btrfs_release_path(swarn->path);
296 goto err;
299 eb = swarn->path->nodes[0];
300 inode_item = btrfs_item_ptr(eb, swarn->path->slots[0],
301 struct btrfs_inode_item);
302 isize = btrfs_inode_size(eb, inode_item);
303 nlink = btrfs_inode_nlink(eb, inode_item);
304 btrfs_release_path(swarn->path);
306 ipath = init_ipath(4096, local_root, swarn->path);
307 if (IS_ERR(ipath)) {
308 ret = PTR_ERR(ipath);
309 ipath = NULL;
310 goto err;
312 ret = paths_from_inode(inum, ipath);
314 if (ret < 0)
315 goto err;
318 * we deliberately ignore the bit ipath might have been too small to
319 * hold all of the paths here
321 for (i = 0; i < ipath->fspath->elem_cnt; ++i)
322 printk(KERN_WARNING "btrfs: %s at logical %llu on dev "
323 "%s, sector %llu, root %llu, inode %llu, offset %llu, "
324 "length %llu, links %u (path: %s)\n", swarn->errstr,
325 swarn->logical, swarn->dev->name,
326 (unsigned long long)swarn->sector, root, inum, offset,
327 min(isize - offset, (u64)PAGE_SIZE), nlink,
328 (char *)(unsigned long)ipath->fspath->val[i]);
330 free_ipath(ipath);
331 return 0;
333 err:
334 printk(KERN_WARNING "btrfs: %s at logical %llu on dev "
335 "%s, sector %llu, root %llu, inode %llu, offset %llu: path "
336 "resolving failed with ret=%d\n", swarn->errstr,
337 swarn->logical, swarn->dev->name,
338 (unsigned long long)swarn->sector, root, inum, offset, ret);
340 free_ipath(ipath);
341 return 0;
344 static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
346 struct btrfs_device *dev = sblock->sdev->dev;
347 struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
348 struct btrfs_path *path;
349 struct btrfs_key found_key;
350 struct extent_buffer *eb;
351 struct btrfs_extent_item *ei;
352 struct scrub_warning swarn;
353 u32 item_size;
354 int ret;
355 u64 ref_root;
356 u8 ref_level;
357 unsigned long ptr = 0;
358 const int bufsize = 4096;
359 u64 extent_item_pos;
361 path = btrfs_alloc_path();
363 swarn.scratch_buf = kmalloc(bufsize, GFP_NOFS);
364 swarn.msg_buf = kmalloc(bufsize, GFP_NOFS);
365 BUG_ON(sblock->page_count < 1);
366 swarn.sector = (sblock->pagev[0].physical) >> 9;
367 swarn.logical = sblock->pagev[0].logical;
368 swarn.errstr = errstr;
369 swarn.dev = dev;
370 swarn.msg_bufsize = bufsize;
371 swarn.scratch_bufsize = bufsize;
373 if (!path || !swarn.scratch_buf || !swarn.msg_buf)
374 goto out;
376 ret = extent_from_logical(fs_info, swarn.logical, path, &found_key);
377 if (ret < 0)
378 goto out;
380 extent_item_pos = swarn.logical - found_key.objectid;
381 swarn.extent_item_size = found_key.offset;
383 eb = path->nodes[0];
384 ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
385 item_size = btrfs_item_size_nr(eb, path->slots[0]);
386 btrfs_release_path(path);
388 if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
389 do {
390 ret = tree_backref_for_extent(&ptr, eb, ei, item_size,
391 &ref_root, &ref_level);
392 printk(KERN_WARNING
393 "btrfs: %s at logical %llu on dev %s, "
394 "sector %llu: metadata %s (level %d) in tree "
395 "%llu\n", errstr, swarn.logical, dev->name,
396 (unsigned long long)swarn.sector,
397 ref_level ? "node" : "leaf",
398 ret < 0 ? -1 : ref_level,
399 ret < 0 ? -1 : ref_root);
400 } while (ret != 1);
401 } else {
402 swarn.path = path;
403 iterate_extent_inodes(fs_info, found_key.objectid,
404 extent_item_pos, 1,
405 scrub_print_warning_inode, &swarn);
408 out:
409 btrfs_free_path(path);
410 kfree(swarn.scratch_buf);
411 kfree(swarn.msg_buf);
414 static int scrub_fixup_readpage(u64 inum, u64 offset, u64 root, void *ctx)
416 struct page *page = NULL;
417 unsigned long index;
418 struct scrub_fixup_nodatasum *fixup = ctx;
419 int ret;
420 int corrected = 0;
421 struct btrfs_key key;
422 struct inode *inode = NULL;
423 u64 end = offset + PAGE_SIZE - 1;
424 struct btrfs_root *local_root;
426 key.objectid = root;
427 key.type = BTRFS_ROOT_ITEM_KEY;
428 key.offset = (u64)-1;
429 local_root = btrfs_read_fs_root_no_name(fixup->root->fs_info, &key);
430 if (IS_ERR(local_root))
431 return PTR_ERR(local_root);
433 key.type = BTRFS_INODE_ITEM_KEY;
434 key.objectid = inum;
435 key.offset = 0;
436 inode = btrfs_iget(fixup->root->fs_info->sb, &key, local_root, NULL);
437 if (IS_ERR(inode))
438 return PTR_ERR(inode);
440 index = offset >> PAGE_CACHE_SHIFT;
442 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
443 if (!page) {
444 ret = -ENOMEM;
445 goto out;
448 if (PageUptodate(page)) {
449 struct btrfs_mapping_tree *map_tree;
450 if (PageDirty(page)) {
452 * we need to write the data to the defect sector. the
453 * data that was in that sector is not in memory,
454 * because the page was modified. we must not write the
455 * modified page to that sector.
457 * TODO: what could be done here: wait for the delalloc
458 * runner to write out that page (might involve
459 * COW) and see whether the sector is still
460 * referenced afterwards.
462 * For the meantime, we'll treat this error
463 * incorrectable, although there is a chance that a
464 * later scrub will find the bad sector again and that
465 * there's no dirty page in memory, then.
467 ret = -EIO;
468 goto out;
470 map_tree = &BTRFS_I(inode)->root->fs_info->mapping_tree;
471 ret = repair_io_failure(map_tree, offset, PAGE_SIZE,
472 fixup->logical, page,
473 fixup->mirror_num);
474 unlock_page(page);
475 corrected = !ret;
476 } else {
478 * we need to get good data first. the general readpage path
479 * will call repair_io_failure for us, we just have to make
480 * sure we read the bad mirror.
482 ret = set_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
483 EXTENT_DAMAGED, GFP_NOFS);
484 if (ret) {
485 /* set_extent_bits should give proper error */
486 WARN_ON(ret > 0);
487 if (ret > 0)
488 ret = -EFAULT;
489 goto out;
492 ret = extent_read_full_page(&BTRFS_I(inode)->io_tree, page,
493 btrfs_get_extent,
494 fixup->mirror_num);
495 wait_on_page_locked(page);
497 corrected = !test_range_bit(&BTRFS_I(inode)->io_tree, offset,
498 end, EXTENT_DAMAGED, 0, NULL);
499 if (!corrected)
500 clear_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
501 EXTENT_DAMAGED, GFP_NOFS);
504 out:
505 if (page)
506 put_page(page);
507 if (inode)
508 iput(inode);
510 if (ret < 0)
511 return ret;
513 if (ret == 0 && corrected) {
515 * we only need to call readpage for one of the inodes belonging
516 * to this extent. so make iterate_extent_inodes stop
518 return 1;
521 return -EIO;
524 static void scrub_fixup_nodatasum(struct btrfs_work *work)
526 int ret;
527 struct scrub_fixup_nodatasum *fixup;
528 struct scrub_dev *sdev;
529 struct btrfs_trans_handle *trans = NULL;
530 struct btrfs_fs_info *fs_info;
531 struct btrfs_path *path;
532 int uncorrectable = 0;
534 fixup = container_of(work, struct scrub_fixup_nodatasum, work);
535 sdev = fixup->sdev;
536 fs_info = fixup->root->fs_info;
538 path = btrfs_alloc_path();
539 if (!path) {
540 spin_lock(&sdev->stat_lock);
541 ++sdev->stat.malloc_errors;
542 spin_unlock(&sdev->stat_lock);
543 uncorrectable = 1;
544 goto out;
547 trans = btrfs_join_transaction(fixup->root);
548 if (IS_ERR(trans)) {
549 uncorrectable = 1;
550 goto out;
554 * the idea is to trigger a regular read through the standard path. we
555 * read a page from the (failed) logical address by specifying the
556 * corresponding copynum of the failed sector. thus, that readpage is
557 * expected to fail.
558 * that is the point where on-the-fly error correction will kick in
559 * (once it's finished) and rewrite the failed sector if a good copy
560 * can be found.
562 ret = iterate_inodes_from_logical(fixup->logical, fixup->root->fs_info,
563 path, scrub_fixup_readpage,
564 fixup);
565 if (ret < 0) {
566 uncorrectable = 1;
567 goto out;
569 WARN_ON(ret != 1);
571 spin_lock(&sdev->stat_lock);
572 ++sdev->stat.corrected_errors;
573 spin_unlock(&sdev->stat_lock);
575 out:
576 if (trans && !IS_ERR(trans))
577 btrfs_end_transaction(trans, fixup->root);
578 if (uncorrectable) {
579 spin_lock(&sdev->stat_lock);
580 ++sdev->stat.uncorrectable_errors;
581 spin_unlock(&sdev->stat_lock);
582 printk_ratelimited(KERN_ERR
583 "btrfs: unable to fixup (nodatasum) error at logical %llu on dev %s\n",
584 (unsigned long long)fixup->logical, sdev->dev->name);
587 btrfs_free_path(path);
588 kfree(fixup);
590 /* see caller why we're pretending to be paused in the scrub counters */
591 mutex_lock(&fs_info->scrub_lock);
592 atomic_dec(&fs_info->scrubs_running);
593 atomic_dec(&fs_info->scrubs_paused);
594 mutex_unlock(&fs_info->scrub_lock);
595 atomic_dec(&sdev->fixup_cnt);
596 wake_up(&fs_info->scrub_pause_wait);
597 wake_up(&sdev->list_wait);
601 * scrub_handle_errored_block gets called when either verification of the
602 * pages failed or the bio failed to read, e.g. with EIO. In the latter
603 * case, this function handles all pages in the bio, even though only one
604 * may be bad.
605 * The goal of this function is to repair the errored block by using the
606 * contents of one of the mirrors.
608 static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
610 struct scrub_dev *sdev = sblock_to_check->sdev;
611 struct btrfs_fs_info *fs_info;
612 u64 length;
613 u64 logical;
614 u64 generation;
615 unsigned int failed_mirror_index;
616 unsigned int is_metadata;
617 unsigned int have_csum;
618 u8 *csum;
619 struct scrub_block *sblocks_for_recheck; /* holds one for each mirror */
620 struct scrub_block *sblock_bad;
621 int ret;
622 int mirror_index;
623 int page_num;
624 int success;
625 static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
626 DEFAULT_RATELIMIT_BURST);
628 BUG_ON(sblock_to_check->page_count < 1);
629 fs_info = sdev->dev->dev_root->fs_info;
630 length = sblock_to_check->page_count * PAGE_SIZE;
631 logical = sblock_to_check->pagev[0].logical;
632 generation = sblock_to_check->pagev[0].generation;
633 BUG_ON(sblock_to_check->pagev[0].mirror_num < 1);
634 failed_mirror_index = sblock_to_check->pagev[0].mirror_num - 1;
635 is_metadata = !(sblock_to_check->pagev[0].flags &
636 BTRFS_EXTENT_FLAG_DATA);
637 have_csum = sblock_to_check->pagev[0].have_csum;
638 csum = sblock_to_check->pagev[0].csum;
641 * read all mirrors one after the other. This includes to
642 * re-read the extent or metadata block that failed (that was
643 * the cause that this fixup code is called) another time,
644 * page by page this time in order to know which pages
645 * caused I/O errors and which ones are good (for all mirrors).
646 * It is the goal to handle the situation when more than one
647 * mirror contains I/O errors, but the errors do not
648 * overlap, i.e. the data can be repaired by selecting the
649 * pages from those mirrors without I/O error on the
650 * particular pages. One example (with blocks >= 2 * PAGE_SIZE)
651 * would be that mirror #1 has an I/O error on the first page,
652 * the second page is good, and mirror #2 has an I/O error on
653 * the second page, but the first page is good.
654 * Then the first page of the first mirror can be repaired by
655 * taking the first page of the second mirror, and the
656 * second page of the second mirror can be repaired by
657 * copying the contents of the 2nd page of the 1st mirror.
658 * One more note: if the pages of one mirror contain I/O
659 * errors, the checksum cannot be verified. In order to get
660 * the best data for repairing, the first attempt is to find
661 * a mirror without I/O errors and with a validated checksum.
662 * Only if this is not possible, the pages are picked from
663 * mirrors with I/O errors without considering the checksum.
664 * If the latter is the case, at the end, the checksum of the
665 * repaired area is verified in order to correctly maintain
666 * the statistics.
669 sblocks_for_recheck = kzalloc(BTRFS_MAX_MIRRORS *
670 sizeof(*sblocks_for_recheck),
671 GFP_NOFS);
672 if (!sblocks_for_recheck) {
673 spin_lock(&sdev->stat_lock);
674 sdev->stat.malloc_errors++;
675 sdev->stat.read_errors++;
676 sdev->stat.uncorrectable_errors++;
677 spin_unlock(&sdev->stat_lock);
678 goto out;
681 /* setup the context, map the logical blocks and alloc the pages */
682 ret = scrub_setup_recheck_block(sdev, &fs_info->mapping_tree, length,
683 logical, sblocks_for_recheck);
684 if (ret) {
685 spin_lock(&sdev->stat_lock);
686 sdev->stat.read_errors++;
687 sdev->stat.uncorrectable_errors++;
688 spin_unlock(&sdev->stat_lock);
689 goto out;
691 BUG_ON(failed_mirror_index >= BTRFS_MAX_MIRRORS);
692 sblock_bad = sblocks_for_recheck + failed_mirror_index;
694 /* build and submit the bios for the failed mirror, check checksums */
695 ret = scrub_recheck_block(fs_info, sblock_bad, is_metadata, have_csum,
696 csum, generation, sdev->csum_size);
697 if (ret) {
698 spin_lock(&sdev->stat_lock);
699 sdev->stat.read_errors++;
700 sdev->stat.uncorrectable_errors++;
701 spin_unlock(&sdev->stat_lock);
702 goto out;
705 if (!sblock_bad->header_error && !sblock_bad->checksum_error &&
706 sblock_bad->no_io_error_seen) {
708 * the error disappeared after reading page by page, or
709 * the area was part of a huge bio and other parts of the
710 * bio caused I/O errors, or the block layer merged several
711 * read requests into one and the error is caused by a
712 * different bio (usually one of the two latter cases is
713 * the cause)
715 spin_lock(&sdev->stat_lock);
716 sdev->stat.unverified_errors++;
717 spin_unlock(&sdev->stat_lock);
719 goto out;
722 if (!sblock_bad->no_io_error_seen) {
723 spin_lock(&sdev->stat_lock);
724 sdev->stat.read_errors++;
725 spin_unlock(&sdev->stat_lock);
726 if (__ratelimit(&_rs))
727 scrub_print_warning("i/o error", sblock_to_check);
728 } else if (sblock_bad->checksum_error) {
729 spin_lock(&sdev->stat_lock);
730 sdev->stat.csum_errors++;
731 spin_unlock(&sdev->stat_lock);
732 if (__ratelimit(&_rs))
733 scrub_print_warning("checksum error", sblock_to_check);
734 } else if (sblock_bad->header_error) {
735 spin_lock(&sdev->stat_lock);
736 sdev->stat.verify_errors++;
737 spin_unlock(&sdev->stat_lock);
738 if (__ratelimit(&_rs))
739 scrub_print_warning("checksum/header error",
740 sblock_to_check);
743 if (sdev->readonly)
744 goto did_not_correct_error;
746 if (!is_metadata && !have_csum) {
747 struct scrub_fixup_nodatasum *fixup_nodatasum;
750 * !is_metadata and !have_csum, this means that the data
751 * might not be COW'ed, that it might be modified
752 * concurrently. The general strategy to work on the
753 * commit root does not help in the case when COW is not
754 * used.
756 fixup_nodatasum = kzalloc(sizeof(*fixup_nodatasum), GFP_NOFS);
757 if (!fixup_nodatasum)
758 goto did_not_correct_error;
759 fixup_nodatasum->sdev = sdev;
760 fixup_nodatasum->logical = logical;
761 fixup_nodatasum->root = fs_info->extent_root;
762 fixup_nodatasum->mirror_num = failed_mirror_index + 1;
764 * increment scrubs_running to prevent cancel requests from
765 * completing as long as a fixup worker is running. we must also
766 * increment scrubs_paused to prevent deadlocking on pause
767 * requests used for transactions commits (as the worker uses a
768 * transaction context). it is safe to regard the fixup worker
769 * as paused for all matters practical. effectively, we only
770 * avoid cancellation requests from completing.
772 mutex_lock(&fs_info->scrub_lock);
773 atomic_inc(&fs_info->scrubs_running);
774 atomic_inc(&fs_info->scrubs_paused);
775 mutex_unlock(&fs_info->scrub_lock);
776 atomic_inc(&sdev->fixup_cnt);
777 fixup_nodatasum->work.func = scrub_fixup_nodatasum;
778 btrfs_queue_worker(&fs_info->scrub_workers,
779 &fixup_nodatasum->work);
780 goto out;
784 * now build and submit the bios for the other mirrors, check
785 * checksums
787 for (mirror_index = 0;
788 mirror_index < BTRFS_MAX_MIRRORS &&
789 sblocks_for_recheck[mirror_index].page_count > 0;
790 mirror_index++) {
791 if (mirror_index == failed_mirror_index)
792 continue;
794 /* build and submit the bios, check checksums */
795 ret = scrub_recheck_block(fs_info,
796 sblocks_for_recheck + mirror_index,
797 is_metadata, have_csum, csum,
798 generation, sdev->csum_size);
799 if (ret)
800 goto did_not_correct_error;
804 * first try to pick the mirror which is completely without I/O
805 * errors and also does not have a checksum error.
806 * If one is found, and if a checksum is present, the full block
807 * that is known to contain an error is rewritten. Afterwards
808 * the block is known to be corrected.
809 * If a mirror is found which is completely correct, and no
810 * checksum is present, only those pages are rewritten that had
811 * an I/O error in the block to be repaired, since it cannot be
812 * determined, which copy of the other pages is better (and it
813 * could happen otherwise that a correct page would be
814 * overwritten by a bad one).
816 for (mirror_index = 0;
817 mirror_index < BTRFS_MAX_MIRRORS &&
818 sblocks_for_recheck[mirror_index].page_count > 0;
819 mirror_index++) {
820 struct scrub_block *sblock_other = sblocks_for_recheck +
821 mirror_index;
823 if (!sblock_other->header_error &&
824 !sblock_other->checksum_error &&
825 sblock_other->no_io_error_seen) {
826 int force_write = is_metadata || have_csum;
828 ret = scrub_repair_block_from_good_copy(sblock_bad,
829 sblock_other,
830 force_write);
831 if (0 == ret)
832 goto corrected_error;
837 * in case of I/O errors in the area that is supposed to be
838 * repaired, continue by picking good copies of those pages.
839 * Select the good pages from mirrors to rewrite bad pages from
840 * the area to fix. Afterwards verify the checksum of the block
841 * that is supposed to be repaired. This verification step is
842 * only done for the purpose of statistic counting and for the
843 * final scrub report, whether errors remain.
844 * A perfect algorithm could make use of the checksum and try
845 * all possible combinations of pages from the different mirrors
846 * until the checksum verification succeeds. For example, when
847 * the 2nd page of mirror #1 faces I/O errors, and the 2nd page
848 * of mirror #2 is readable but the final checksum test fails,
849 * then the 2nd page of mirror #3 could be tried, whether now
850 * the final checksum succeedes. But this would be a rare
851 * exception and is therefore not implemented. At least it is
852 * avoided that the good copy is overwritten.
853 * A more useful improvement would be to pick the sectors
854 * without I/O error based on sector sizes (512 bytes on legacy
855 * disks) instead of on PAGE_SIZE. Then maybe 512 byte of one
856 * mirror could be repaired by taking 512 byte of a different
857 * mirror, even if other 512 byte sectors in the same PAGE_SIZE
858 * area are unreadable.
861 /* can only fix I/O errors from here on */
862 if (sblock_bad->no_io_error_seen)
863 goto did_not_correct_error;
865 success = 1;
866 for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
867 struct scrub_page *page_bad = sblock_bad->pagev + page_num;
869 if (!page_bad->io_error)
870 continue;
872 for (mirror_index = 0;
873 mirror_index < BTRFS_MAX_MIRRORS &&
874 sblocks_for_recheck[mirror_index].page_count > 0;
875 mirror_index++) {
876 struct scrub_block *sblock_other = sblocks_for_recheck +
877 mirror_index;
878 struct scrub_page *page_other = sblock_other->pagev +
879 page_num;
881 if (!page_other->io_error) {
882 ret = scrub_repair_page_from_good_copy(
883 sblock_bad, sblock_other, page_num, 0);
884 if (0 == ret) {
885 page_bad->io_error = 0;
886 break; /* succeeded for this page */
891 if (page_bad->io_error) {
892 /* did not find a mirror to copy the page from */
893 success = 0;
897 if (success) {
898 if (is_metadata || have_csum) {
900 * need to verify the checksum now that all
901 * sectors on disk are repaired (the write
902 * request for data to be repaired is on its way).
903 * Just be lazy and use scrub_recheck_block()
904 * which re-reads the data before the checksum
905 * is verified, but most likely the data comes out
906 * of the page cache.
908 ret = scrub_recheck_block(fs_info, sblock_bad,
909 is_metadata, have_csum, csum,
910 generation, sdev->csum_size);
911 if (!ret && !sblock_bad->header_error &&
912 !sblock_bad->checksum_error &&
913 sblock_bad->no_io_error_seen)
914 goto corrected_error;
915 else
916 goto did_not_correct_error;
917 } else {
918 corrected_error:
919 spin_lock(&sdev->stat_lock);
920 sdev->stat.corrected_errors++;
921 spin_unlock(&sdev->stat_lock);
922 printk_ratelimited(KERN_ERR
923 "btrfs: fixed up error at logical %llu on dev %s\n",
924 (unsigned long long)logical, sdev->dev->name);
926 } else {
927 did_not_correct_error:
928 spin_lock(&sdev->stat_lock);
929 sdev->stat.uncorrectable_errors++;
930 spin_unlock(&sdev->stat_lock);
931 printk_ratelimited(KERN_ERR
932 "btrfs: unable to fixup (regular) error at logical %llu on dev %s\n",
933 (unsigned long long)logical, sdev->dev->name);
936 out:
937 if (sblocks_for_recheck) {
938 for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS;
939 mirror_index++) {
940 struct scrub_block *sblock = sblocks_for_recheck +
941 mirror_index;
942 int page_index;
944 for (page_index = 0; page_index < SCRUB_PAGES_PER_BIO;
945 page_index++)
946 if (sblock->pagev[page_index].page)
947 __free_page(
948 sblock->pagev[page_index].page);
950 kfree(sblocks_for_recheck);
953 return 0;
956 static int scrub_setup_recheck_block(struct scrub_dev *sdev,
957 struct btrfs_mapping_tree *map_tree,
958 u64 length, u64 logical,
959 struct scrub_block *sblocks_for_recheck)
961 int page_index;
962 int mirror_index;
963 int ret;
966 * note: the three members sdev, ref_count and outstanding_pages
967 * are not used (and not set) in the blocks that are used for
968 * the recheck procedure
971 page_index = 0;
972 while (length > 0) {
973 u64 sublen = min_t(u64, length, PAGE_SIZE);
974 u64 mapped_length = sublen;
975 struct btrfs_bio *bbio = NULL;
978 * with a length of PAGE_SIZE, each returned stripe
979 * represents one mirror
981 ret = btrfs_map_block(map_tree, WRITE, logical, &mapped_length,
982 &bbio, 0);
983 if (ret || !bbio || mapped_length < sublen) {
984 kfree(bbio);
985 return -EIO;
988 BUG_ON(page_index >= SCRUB_PAGES_PER_BIO);
989 for (mirror_index = 0; mirror_index < (int)bbio->num_stripes;
990 mirror_index++) {
991 struct scrub_block *sblock;
992 struct scrub_page *page;
994 if (mirror_index >= BTRFS_MAX_MIRRORS)
995 continue;
997 sblock = sblocks_for_recheck + mirror_index;
998 page = sblock->pagev + page_index;
999 page->logical = logical;
1000 page->physical = bbio->stripes[mirror_index].physical;
1001 page->bdev = bbio->stripes[mirror_index].dev->bdev;
1002 page->mirror_num = mirror_index + 1;
1003 page->page = alloc_page(GFP_NOFS);
1004 if (!page->page) {
1005 spin_lock(&sdev->stat_lock);
1006 sdev->stat.malloc_errors++;
1007 spin_unlock(&sdev->stat_lock);
1008 return -ENOMEM;
1010 sblock->page_count++;
1012 kfree(bbio);
1013 length -= sublen;
1014 logical += sublen;
1015 page_index++;
1018 return 0;
1022 * this function will check the on disk data for checksum errors, header
1023 * errors and read I/O errors. If any I/O errors happen, the exact pages
1024 * which are errored are marked as being bad. The goal is to enable scrub
1025 * to take those pages that are not errored from all the mirrors so that
1026 * the pages that are errored in the just handled mirror can be repaired.
1028 static int scrub_recheck_block(struct btrfs_fs_info *fs_info,
1029 struct scrub_block *sblock, int is_metadata,
1030 int have_csum, u8 *csum, u64 generation,
1031 u16 csum_size)
1033 int page_num;
1035 sblock->no_io_error_seen = 1;
1036 sblock->header_error = 0;
1037 sblock->checksum_error = 0;
1039 for (page_num = 0; page_num < sblock->page_count; page_num++) {
1040 struct bio *bio;
1041 int ret;
1042 struct scrub_page *page = sblock->pagev + page_num;
1043 DECLARE_COMPLETION_ONSTACK(complete);
1045 BUG_ON(!page->page);
1046 bio = bio_alloc(GFP_NOFS, 1);
1047 if (!bio)
1048 return -EIO;
1049 bio->bi_bdev = page->bdev;
1050 bio->bi_sector = page->physical >> 9;
1051 bio->bi_end_io = scrub_complete_bio_end_io;
1052 bio->bi_private = &complete;
1054 ret = bio_add_page(bio, page->page, PAGE_SIZE, 0);
1055 if (PAGE_SIZE != ret) {
1056 bio_put(bio);
1057 return -EIO;
1059 btrfsic_submit_bio(READ, bio);
1061 /* this will also unplug the queue */
1062 wait_for_completion(&complete);
1064 page->io_error = !test_bit(BIO_UPTODATE, &bio->bi_flags);
1065 if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1066 sblock->no_io_error_seen = 0;
1067 bio_put(bio);
1070 if (sblock->no_io_error_seen)
1071 scrub_recheck_block_checksum(fs_info, sblock, is_metadata,
1072 have_csum, csum, generation,
1073 csum_size);
1075 return 0;
1078 static void scrub_recheck_block_checksum(struct btrfs_fs_info *fs_info,
1079 struct scrub_block *sblock,
1080 int is_metadata, int have_csum,
1081 const u8 *csum, u64 generation,
1082 u16 csum_size)
1084 int page_num;
1085 u8 calculated_csum[BTRFS_CSUM_SIZE];
1086 u32 crc = ~(u32)0;
1087 struct btrfs_root *root = fs_info->extent_root;
1088 void *mapped_buffer;
1090 BUG_ON(!sblock->pagev[0].page);
1091 if (is_metadata) {
1092 struct btrfs_header *h;
1094 mapped_buffer = kmap_atomic(sblock->pagev[0].page);
1095 h = (struct btrfs_header *)mapped_buffer;
1097 if (sblock->pagev[0].logical != le64_to_cpu(h->bytenr) ||
1098 generation != le64_to_cpu(h->generation) ||
1099 memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE) ||
1100 memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
1101 BTRFS_UUID_SIZE))
1102 sblock->header_error = 1;
1103 csum = h->csum;
1104 } else {
1105 if (!have_csum)
1106 return;
1108 mapped_buffer = kmap_atomic(sblock->pagev[0].page);
1111 for (page_num = 0;;) {
1112 if (page_num == 0 && is_metadata)
1113 crc = btrfs_csum_data(root,
1114 ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE,
1115 crc, PAGE_SIZE - BTRFS_CSUM_SIZE);
1116 else
1117 crc = btrfs_csum_data(root, mapped_buffer, crc,
1118 PAGE_SIZE);
1120 kunmap_atomic(mapped_buffer);
1121 page_num++;
1122 if (page_num >= sblock->page_count)
1123 break;
1124 BUG_ON(!sblock->pagev[page_num].page);
1126 mapped_buffer = kmap_atomic(sblock->pagev[page_num].page);
1129 btrfs_csum_final(crc, calculated_csum);
1130 if (memcmp(calculated_csum, csum, csum_size))
1131 sblock->checksum_error = 1;
1134 static void scrub_complete_bio_end_io(struct bio *bio, int err)
1136 complete((struct completion *)bio->bi_private);
1139 static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
1140 struct scrub_block *sblock_good,
1141 int force_write)
1143 int page_num;
1144 int ret = 0;
1146 for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
1147 int ret_sub;
1149 ret_sub = scrub_repair_page_from_good_copy(sblock_bad,
1150 sblock_good,
1151 page_num,
1152 force_write);
1153 if (ret_sub)
1154 ret = ret_sub;
1157 return ret;
1160 static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
1161 struct scrub_block *sblock_good,
1162 int page_num, int force_write)
1164 struct scrub_page *page_bad = sblock_bad->pagev + page_num;
1165 struct scrub_page *page_good = sblock_good->pagev + page_num;
1167 BUG_ON(sblock_bad->pagev[page_num].page == NULL);
1168 BUG_ON(sblock_good->pagev[page_num].page == NULL);
1169 if (force_write || sblock_bad->header_error ||
1170 sblock_bad->checksum_error || page_bad->io_error) {
1171 struct bio *bio;
1172 int ret;
1173 DECLARE_COMPLETION_ONSTACK(complete);
1175 bio = bio_alloc(GFP_NOFS, 1);
1176 if (!bio)
1177 return -EIO;
1178 bio->bi_bdev = page_bad->bdev;
1179 bio->bi_sector = page_bad->physical >> 9;
1180 bio->bi_end_io = scrub_complete_bio_end_io;
1181 bio->bi_private = &complete;
1183 ret = bio_add_page(bio, page_good->page, PAGE_SIZE, 0);
1184 if (PAGE_SIZE != ret) {
1185 bio_put(bio);
1186 return -EIO;
1188 btrfsic_submit_bio(WRITE, bio);
1190 /* this will also unplug the queue */
1191 wait_for_completion(&complete);
1192 bio_put(bio);
1195 return 0;
1198 static void scrub_checksum(struct scrub_block *sblock)
1200 u64 flags;
1201 int ret;
1203 BUG_ON(sblock->page_count < 1);
1204 flags = sblock->pagev[0].flags;
1205 ret = 0;
1206 if (flags & BTRFS_EXTENT_FLAG_DATA)
1207 ret = scrub_checksum_data(sblock);
1208 else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1209 ret = scrub_checksum_tree_block(sblock);
1210 else if (flags & BTRFS_EXTENT_FLAG_SUPER)
1211 (void)scrub_checksum_super(sblock);
1212 else
1213 WARN_ON(1);
1214 if (ret)
1215 scrub_handle_errored_block(sblock);
1218 static int scrub_checksum_data(struct scrub_block *sblock)
1220 struct scrub_dev *sdev = sblock->sdev;
1221 u8 csum[BTRFS_CSUM_SIZE];
1222 u8 *on_disk_csum;
1223 struct page *page;
1224 void *buffer;
1225 u32 crc = ~(u32)0;
1226 int fail = 0;
1227 struct btrfs_root *root = sdev->dev->dev_root;
1228 u64 len;
1229 int index;
1231 BUG_ON(sblock->page_count < 1);
1232 if (!sblock->pagev[0].have_csum)
1233 return 0;
1235 on_disk_csum = sblock->pagev[0].csum;
1236 page = sblock->pagev[0].page;
1237 buffer = kmap_atomic(page);
1239 len = sdev->sectorsize;
1240 index = 0;
1241 for (;;) {
1242 u64 l = min_t(u64, len, PAGE_SIZE);
1244 crc = btrfs_csum_data(root, buffer, crc, l);
1245 kunmap_atomic(buffer);
1246 len -= l;
1247 if (len == 0)
1248 break;
1249 index++;
1250 BUG_ON(index >= sblock->page_count);
1251 BUG_ON(!sblock->pagev[index].page);
1252 page = sblock->pagev[index].page;
1253 buffer = kmap_atomic(page);
1256 btrfs_csum_final(crc, csum);
1257 if (memcmp(csum, on_disk_csum, sdev->csum_size))
1258 fail = 1;
1260 return fail;
1263 static int scrub_checksum_tree_block(struct scrub_block *sblock)
1265 struct scrub_dev *sdev = sblock->sdev;
1266 struct btrfs_header *h;
1267 struct btrfs_root *root = sdev->dev->dev_root;
1268 struct btrfs_fs_info *fs_info = root->fs_info;
1269 u8 calculated_csum[BTRFS_CSUM_SIZE];
1270 u8 on_disk_csum[BTRFS_CSUM_SIZE];
1271 struct page *page;
1272 void *mapped_buffer;
1273 u64 mapped_size;
1274 void *p;
1275 u32 crc = ~(u32)0;
1276 int fail = 0;
1277 int crc_fail = 0;
1278 u64 len;
1279 int index;
1281 BUG_ON(sblock->page_count < 1);
1282 page = sblock->pagev[0].page;
1283 mapped_buffer = kmap_atomic(page);
1284 h = (struct btrfs_header *)mapped_buffer;
1285 memcpy(on_disk_csum, h->csum, sdev->csum_size);
1288 * we don't use the getter functions here, as we
1289 * a) don't have an extent buffer and
1290 * b) the page is already kmapped
1293 if (sblock->pagev[0].logical != le64_to_cpu(h->bytenr))
1294 ++fail;
1296 if (sblock->pagev[0].generation != le64_to_cpu(h->generation))
1297 ++fail;
1299 if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
1300 ++fail;
1302 if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
1303 BTRFS_UUID_SIZE))
1304 ++fail;
1306 BUG_ON(sdev->nodesize != sdev->leafsize);
1307 len = sdev->nodesize - BTRFS_CSUM_SIZE;
1308 mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
1309 p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
1310 index = 0;
1311 for (;;) {
1312 u64 l = min_t(u64, len, mapped_size);
1314 crc = btrfs_csum_data(root, p, crc, l);
1315 kunmap_atomic(mapped_buffer);
1316 len -= l;
1317 if (len == 0)
1318 break;
1319 index++;
1320 BUG_ON(index >= sblock->page_count);
1321 BUG_ON(!sblock->pagev[index].page);
1322 page = sblock->pagev[index].page;
1323 mapped_buffer = kmap_atomic(page);
1324 mapped_size = PAGE_SIZE;
1325 p = mapped_buffer;
1328 btrfs_csum_final(crc, calculated_csum);
1329 if (memcmp(calculated_csum, on_disk_csum, sdev->csum_size))
1330 ++crc_fail;
1332 return fail || crc_fail;
1335 static int scrub_checksum_super(struct scrub_block *sblock)
1337 struct btrfs_super_block *s;
1338 struct scrub_dev *sdev = sblock->sdev;
1339 struct btrfs_root *root = sdev->dev->dev_root;
1340 struct btrfs_fs_info *fs_info = root->fs_info;
1341 u8 calculated_csum[BTRFS_CSUM_SIZE];
1342 u8 on_disk_csum[BTRFS_CSUM_SIZE];
1343 struct page *page;
1344 void *mapped_buffer;
1345 u64 mapped_size;
1346 void *p;
1347 u32 crc = ~(u32)0;
1348 int fail = 0;
1349 u64 len;
1350 int index;
1352 BUG_ON(sblock->page_count < 1);
1353 page = sblock->pagev[0].page;
1354 mapped_buffer = kmap_atomic(page);
1355 s = (struct btrfs_super_block *)mapped_buffer;
1356 memcpy(on_disk_csum, s->csum, sdev->csum_size);
1358 if (sblock->pagev[0].logical != le64_to_cpu(s->bytenr))
1359 ++fail;
1361 if (sblock->pagev[0].generation != le64_to_cpu(s->generation))
1362 ++fail;
1364 if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
1365 ++fail;
1367 len = BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE;
1368 mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
1369 p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
1370 index = 0;
1371 for (;;) {
1372 u64 l = min_t(u64, len, mapped_size);
1374 crc = btrfs_csum_data(root, p, crc, l);
1375 kunmap_atomic(mapped_buffer);
1376 len -= l;
1377 if (len == 0)
1378 break;
1379 index++;
1380 BUG_ON(index >= sblock->page_count);
1381 BUG_ON(!sblock->pagev[index].page);
1382 page = sblock->pagev[index].page;
1383 mapped_buffer = kmap_atomic(page);
1384 mapped_size = PAGE_SIZE;
1385 p = mapped_buffer;
1388 btrfs_csum_final(crc, calculated_csum);
1389 if (memcmp(calculated_csum, on_disk_csum, sdev->csum_size))
1390 ++fail;
1392 if (fail) {
1394 * if we find an error in a super block, we just report it.
1395 * They will get written with the next transaction commit
1396 * anyway
1398 spin_lock(&sdev->stat_lock);
1399 ++sdev->stat.super_errors;
1400 spin_unlock(&sdev->stat_lock);
1403 return fail;
1406 static void scrub_block_get(struct scrub_block *sblock)
1408 atomic_inc(&sblock->ref_count);
1411 static void scrub_block_put(struct scrub_block *sblock)
1413 if (atomic_dec_and_test(&sblock->ref_count)) {
1414 int i;
1416 for (i = 0; i < sblock->page_count; i++)
1417 if (sblock->pagev[i].page)
1418 __free_page(sblock->pagev[i].page);
1419 kfree(sblock);
1423 static void scrub_submit(struct scrub_dev *sdev)
1425 struct scrub_bio *sbio;
1427 if (sdev->curr == -1)
1428 return;
1430 sbio = sdev->bios[sdev->curr];
1431 sdev->curr = -1;
1432 atomic_inc(&sdev->in_flight);
1434 btrfsic_submit_bio(READ, sbio->bio);
1437 static int scrub_add_page_to_bio(struct scrub_dev *sdev,
1438 struct scrub_page *spage)
1440 struct scrub_block *sblock = spage->sblock;
1441 struct scrub_bio *sbio;
1442 int ret;
1444 again:
1446 * grab a fresh bio or wait for one to become available
1448 while (sdev->curr == -1) {
1449 spin_lock(&sdev->list_lock);
1450 sdev->curr = sdev->first_free;
1451 if (sdev->curr != -1) {
1452 sdev->first_free = sdev->bios[sdev->curr]->next_free;
1453 sdev->bios[sdev->curr]->next_free = -1;
1454 sdev->bios[sdev->curr]->page_count = 0;
1455 spin_unlock(&sdev->list_lock);
1456 } else {
1457 spin_unlock(&sdev->list_lock);
1458 wait_event(sdev->list_wait, sdev->first_free != -1);
1461 sbio = sdev->bios[sdev->curr];
1462 if (sbio->page_count == 0) {
1463 struct bio *bio;
1465 sbio->physical = spage->physical;
1466 sbio->logical = spage->logical;
1467 bio = sbio->bio;
1468 if (!bio) {
1469 bio = bio_alloc(GFP_NOFS, sdev->pages_per_bio);
1470 if (!bio)
1471 return -ENOMEM;
1472 sbio->bio = bio;
1475 bio->bi_private = sbio;
1476 bio->bi_end_io = scrub_bio_end_io;
1477 bio->bi_bdev = sdev->dev->bdev;
1478 bio->bi_sector = spage->physical >> 9;
1479 sbio->err = 0;
1480 } else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
1481 spage->physical ||
1482 sbio->logical + sbio->page_count * PAGE_SIZE !=
1483 spage->logical) {
1484 scrub_submit(sdev);
1485 goto again;
1488 sbio->pagev[sbio->page_count] = spage;
1489 ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
1490 if (ret != PAGE_SIZE) {
1491 if (sbio->page_count < 1) {
1492 bio_put(sbio->bio);
1493 sbio->bio = NULL;
1494 return -EIO;
1496 scrub_submit(sdev);
1497 goto again;
1500 scrub_block_get(sblock); /* one for the added page */
1501 atomic_inc(&sblock->outstanding_pages);
1502 sbio->page_count++;
1503 if (sbio->page_count == sdev->pages_per_bio)
1504 scrub_submit(sdev);
1506 return 0;
1509 static int scrub_pages(struct scrub_dev *sdev, u64 logical, u64 len,
1510 u64 physical, u64 flags, u64 gen, int mirror_num,
1511 u8 *csum, int force)
1513 struct scrub_block *sblock;
1514 int index;
1516 sblock = kzalloc(sizeof(*sblock), GFP_NOFS);
1517 if (!sblock) {
1518 spin_lock(&sdev->stat_lock);
1519 sdev->stat.malloc_errors++;
1520 spin_unlock(&sdev->stat_lock);
1521 return -ENOMEM;
1524 /* one ref inside this function, plus one for each page later on */
1525 atomic_set(&sblock->ref_count, 1);
1526 sblock->sdev = sdev;
1527 sblock->no_io_error_seen = 1;
1529 for (index = 0; len > 0; index++) {
1530 struct scrub_page *spage = sblock->pagev + index;
1531 u64 l = min_t(u64, len, PAGE_SIZE);
1533 BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
1534 spage->page = alloc_page(GFP_NOFS);
1535 if (!spage->page) {
1536 spin_lock(&sdev->stat_lock);
1537 sdev->stat.malloc_errors++;
1538 spin_unlock(&sdev->stat_lock);
1539 while (index > 0) {
1540 index--;
1541 __free_page(sblock->pagev[index].page);
1543 kfree(sblock);
1544 return -ENOMEM;
1546 spage->sblock = sblock;
1547 spage->bdev = sdev->dev->bdev;
1548 spage->flags = flags;
1549 spage->generation = gen;
1550 spage->logical = logical;
1551 spage->physical = physical;
1552 spage->mirror_num = mirror_num;
1553 if (csum) {
1554 spage->have_csum = 1;
1555 memcpy(spage->csum, csum, sdev->csum_size);
1556 } else {
1557 spage->have_csum = 0;
1559 sblock->page_count++;
1560 len -= l;
1561 logical += l;
1562 physical += l;
1565 BUG_ON(sblock->page_count == 0);
1566 for (index = 0; index < sblock->page_count; index++) {
1567 struct scrub_page *spage = sblock->pagev + index;
1568 int ret;
1570 ret = scrub_add_page_to_bio(sdev, spage);
1571 if (ret) {
1572 scrub_block_put(sblock);
1573 return ret;
1577 if (force)
1578 scrub_submit(sdev);
1580 /* last one frees, either here or in bio completion for last page */
1581 scrub_block_put(sblock);
1582 return 0;
1585 static void scrub_bio_end_io(struct bio *bio, int err)
1587 struct scrub_bio *sbio = bio->bi_private;
1588 struct scrub_dev *sdev = sbio->sdev;
1589 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
1591 sbio->err = err;
1592 sbio->bio = bio;
1594 btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
1597 static void scrub_bio_end_io_worker(struct btrfs_work *work)
1599 struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
1600 struct scrub_dev *sdev = sbio->sdev;
1601 int i;
1603 BUG_ON(sbio->page_count > SCRUB_PAGES_PER_BIO);
1604 if (sbio->err) {
1605 for (i = 0; i < sbio->page_count; i++) {
1606 struct scrub_page *spage = sbio->pagev[i];
1608 spage->io_error = 1;
1609 spage->sblock->no_io_error_seen = 0;
1613 /* now complete the scrub_block items that have all pages completed */
1614 for (i = 0; i < sbio->page_count; i++) {
1615 struct scrub_page *spage = sbio->pagev[i];
1616 struct scrub_block *sblock = spage->sblock;
1618 if (atomic_dec_and_test(&sblock->outstanding_pages))
1619 scrub_block_complete(sblock);
1620 scrub_block_put(sblock);
1623 if (sbio->err) {
1624 /* what is this good for??? */
1625 sbio->bio->bi_flags &= ~(BIO_POOL_MASK - 1);
1626 sbio->bio->bi_flags |= 1 << BIO_UPTODATE;
1627 sbio->bio->bi_phys_segments = 0;
1628 sbio->bio->bi_idx = 0;
1630 for (i = 0; i < sbio->page_count; i++) {
1631 struct bio_vec *bi;
1632 bi = &sbio->bio->bi_io_vec[i];
1633 bi->bv_offset = 0;
1634 bi->bv_len = PAGE_SIZE;
1638 bio_put(sbio->bio);
1639 sbio->bio = NULL;
1640 spin_lock(&sdev->list_lock);
1641 sbio->next_free = sdev->first_free;
1642 sdev->first_free = sbio->index;
1643 spin_unlock(&sdev->list_lock);
1644 atomic_dec(&sdev->in_flight);
1645 wake_up(&sdev->list_wait);
1648 static void scrub_block_complete(struct scrub_block *sblock)
1650 if (!sblock->no_io_error_seen)
1651 scrub_handle_errored_block(sblock);
1652 else
1653 scrub_checksum(sblock);
1656 static int scrub_find_csum(struct scrub_dev *sdev, u64 logical, u64 len,
1657 u8 *csum)
1659 struct btrfs_ordered_sum *sum = NULL;
1660 int ret = 0;
1661 unsigned long i;
1662 unsigned long num_sectors;
1664 while (!list_empty(&sdev->csum_list)) {
1665 sum = list_first_entry(&sdev->csum_list,
1666 struct btrfs_ordered_sum, list);
1667 if (sum->bytenr > logical)
1668 return 0;
1669 if (sum->bytenr + sum->len > logical)
1670 break;
1672 ++sdev->stat.csum_discards;
1673 list_del(&sum->list);
1674 kfree(sum);
1675 sum = NULL;
1677 if (!sum)
1678 return 0;
1680 num_sectors = sum->len / sdev->sectorsize;
1681 for (i = 0; i < num_sectors; ++i) {
1682 if (sum->sums[i].bytenr == logical) {
1683 memcpy(csum, &sum->sums[i].sum, sdev->csum_size);
1684 ret = 1;
1685 break;
1688 if (ret && i == num_sectors - 1) {
1689 list_del(&sum->list);
1690 kfree(sum);
1692 return ret;
1695 /* scrub extent tries to collect up to 64 kB for each bio */
1696 static int scrub_extent(struct scrub_dev *sdev, u64 logical, u64 len,
1697 u64 physical, u64 flags, u64 gen, int mirror_num)
1699 int ret;
1700 u8 csum[BTRFS_CSUM_SIZE];
1701 u32 blocksize;
1703 if (flags & BTRFS_EXTENT_FLAG_DATA) {
1704 blocksize = sdev->sectorsize;
1705 spin_lock(&sdev->stat_lock);
1706 sdev->stat.data_extents_scrubbed++;
1707 sdev->stat.data_bytes_scrubbed += len;
1708 spin_unlock(&sdev->stat_lock);
1709 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1710 BUG_ON(sdev->nodesize != sdev->leafsize);
1711 blocksize = sdev->nodesize;
1712 spin_lock(&sdev->stat_lock);
1713 sdev->stat.tree_extents_scrubbed++;
1714 sdev->stat.tree_bytes_scrubbed += len;
1715 spin_unlock(&sdev->stat_lock);
1716 } else {
1717 blocksize = sdev->sectorsize;
1718 BUG_ON(1);
1721 while (len) {
1722 u64 l = min_t(u64, len, blocksize);
1723 int have_csum = 0;
1725 if (flags & BTRFS_EXTENT_FLAG_DATA) {
1726 /* push csums to sbio */
1727 have_csum = scrub_find_csum(sdev, logical, l, csum);
1728 if (have_csum == 0)
1729 ++sdev->stat.no_csum;
1731 ret = scrub_pages(sdev, logical, l, physical, flags, gen,
1732 mirror_num, have_csum ? csum : NULL, 0);
1733 if (ret)
1734 return ret;
1735 len -= l;
1736 logical += l;
1737 physical += l;
1739 return 0;
1742 static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
1743 struct map_lookup *map, int num, u64 base, u64 length)
1745 struct btrfs_path *path;
1746 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
1747 struct btrfs_root *root = fs_info->extent_root;
1748 struct btrfs_root *csum_root = fs_info->csum_root;
1749 struct btrfs_extent_item *extent;
1750 struct blk_plug plug;
1751 u64 flags;
1752 int ret;
1753 int slot;
1754 int i;
1755 u64 nstripes;
1756 struct extent_buffer *l;
1757 struct btrfs_key key;
1758 u64 physical;
1759 u64 logical;
1760 u64 generation;
1761 int mirror_num;
1762 struct reada_control *reada1;
1763 struct reada_control *reada2;
1764 struct btrfs_key key_start;
1765 struct btrfs_key key_end;
1767 u64 increment = map->stripe_len;
1768 u64 offset;
1770 nstripes = length;
1771 offset = 0;
1772 do_div(nstripes, map->stripe_len);
1773 if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
1774 offset = map->stripe_len * num;
1775 increment = map->stripe_len * map->num_stripes;
1776 mirror_num = 1;
1777 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1778 int factor = map->num_stripes / map->sub_stripes;
1779 offset = map->stripe_len * (num / map->sub_stripes);
1780 increment = map->stripe_len * factor;
1781 mirror_num = num % map->sub_stripes + 1;
1782 } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
1783 increment = map->stripe_len;
1784 mirror_num = num % map->num_stripes + 1;
1785 } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
1786 increment = map->stripe_len;
1787 mirror_num = num % map->num_stripes + 1;
1788 } else {
1789 increment = map->stripe_len;
1790 mirror_num = 1;
1793 path = btrfs_alloc_path();
1794 if (!path)
1795 return -ENOMEM;
1798 * work on commit root. The related disk blocks are static as
1799 * long as COW is applied. This means, it is save to rewrite
1800 * them to repair disk errors without any race conditions
1802 path->search_commit_root = 1;
1803 path->skip_locking = 1;
1806 * trigger the readahead for extent tree csum tree and wait for
1807 * completion. During readahead, the scrub is officially paused
1808 * to not hold off transaction commits
1810 logical = base + offset;
1812 wait_event(sdev->list_wait,
1813 atomic_read(&sdev->in_flight) == 0);
1814 atomic_inc(&fs_info->scrubs_paused);
1815 wake_up(&fs_info->scrub_pause_wait);
1817 /* FIXME it might be better to start readahead at commit root */
1818 key_start.objectid = logical;
1819 key_start.type = BTRFS_EXTENT_ITEM_KEY;
1820 key_start.offset = (u64)0;
1821 key_end.objectid = base + offset + nstripes * increment;
1822 key_end.type = BTRFS_EXTENT_ITEM_KEY;
1823 key_end.offset = (u64)0;
1824 reada1 = btrfs_reada_add(root, &key_start, &key_end);
1826 key_start.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
1827 key_start.type = BTRFS_EXTENT_CSUM_KEY;
1828 key_start.offset = logical;
1829 key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
1830 key_end.type = BTRFS_EXTENT_CSUM_KEY;
1831 key_end.offset = base + offset + nstripes * increment;
1832 reada2 = btrfs_reada_add(csum_root, &key_start, &key_end);
1834 if (!IS_ERR(reada1))
1835 btrfs_reada_wait(reada1);
1836 if (!IS_ERR(reada2))
1837 btrfs_reada_wait(reada2);
1839 mutex_lock(&fs_info->scrub_lock);
1840 while (atomic_read(&fs_info->scrub_pause_req)) {
1841 mutex_unlock(&fs_info->scrub_lock);
1842 wait_event(fs_info->scrub_pause_wait,
1843 atomic_read(&fs_info->scrub_pause_req) == 0);
1844 mutex_lock(&fs_info->scrub_lock);
1846 atomic_dec(&fs_info->scrubs_paused);
1847 mutex_unlock(&fs_info->scrub_lock);
1848 wake_up(&fs_info->scrub_pause_wait);
1851 * collect all data csums for the stripe to avoid seeking during
1852 * the scrub. This might currently (crc32) end up to be about 1MB
1854 blk_start_plug(&plug);
1857 * now find all extents for each stripe and scrub them
1859 logical = base + offset;
1860 physical = map->stripes[num].physical;
1861 ret = 0;
1862 for (i = 0; i < nstripes; ++i) {
1864 * canceled?
1866 if (atomic_read(&fs_info->scrub_cancel_req) ||
1867 atomic_read(&sdev->cancel_req)) {
1868 ret = -ECANCELED;
1869 goto out;
1872 * check to see if we have to pause
1874 if (atomic_read(&fs_info->scrub_pause_req)) {
1875 /* push queued extents */
1876 scrub_submit(sdev);
1877 wait_event(sdev->list_wait,
1878 atomic_read(&sdev->in_flight) == 0);
1879 atomic_inc(&fs_info->scrubs_paused);
1880 wake_up(&fs_info->scrub_pause_wait);
1881 mutex_lock(&fs_info->scrub_lock);
1882 while (atomic_read(&fs_info->scrub_pause_req)) {
1883 mutex_unlock(&fs_info->scrub_lock);
1884 wait_event(fs_info->scrub_pause_wait,
1885 atomic_read(&fs_info->scrub_pause_req) == 0);
1886 mutex_lock(&fs_info->scrub_lock);
1888 atomic_dec(&fs_info->scrubs_paused);
1889 mutex_unlock(&fs_info->scrub_lock);
1890 wake_up(&fs_info->scrub_pause_wait);
1893 ret = btrfs_lookup_csums_range(csum_root, logical,
1894 logical + map->stripe_len - 1,
1895 &sdev->csum_list, 1);
1896 if (ret)
1897 goto out;
1899 key.objectid = logical;
1900 key.type = BTRFS_EXTENT_ITEM_KEY;
1901 key.offset = (u64)0;
1903 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1904 if (ret < 0)
1905 goto out;
1906 if (ret > 0) {
1907 ret = btrfs_previous_item(root, path, 0,
1908 BTRFS_EXTENT_ITEM_KEY);
1909 if (ret < 0)
1910 goto out;
1911 if (ret > 0) {
1912 /* there's no smaller item, so stick with the
1913 * larger one */
1914 btrfs_release_path(path);
1915 ret = btrfs_search_slot(NULL, root, &key,
1916 path, 0, 0);
1917 if (ret < 0)
1918 goto out;
1922 while (1) {
1923 l = path->nodes[0];
1924 slot = path->slots[0];
1925 if (slot >= btrfs_header_nritems(l)) {
1926 ret = btrfs_next_leaf(root, path);
1927 if (ret == 0)
1928 continue;
1929 if (ret < 0)
1930 goto out;
1932 break;
1934 btrfs_item_key_to_cpu(l, &key, slot);
1936 if (key.objectid + key.offset <= logical)
1937 goto next;
1939 if (key.objectid >= logical + map->stripe_len)
1940 break;
1942 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY)
1943 goto next;
1945 extent = btrfs_item_ptr(l, slot,
1946 struct btrfs_extent_item);
1947 flags = btrfs_extent_flags(l, extent);
1948 generation = btrfs_extent_generation(l, extent);
1950 if (key.objectid < logical &&
1951 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
1952 printk(KERN_ERR
1953 "btrfs scrub: tree block %llu spanning "
1954 "stripes, ignored. logical=%llu\n",
1955 (unsigned long long)key.objectid,
1956 (unsigned long long)logical);
1957 goto next;
1961 * trim extent to this stripe
1963 if (key.objectid < logical) {
1964 key.offset -= logical - key.objectid;
1965 key.objectid = logical;
1967 if (key.objectid + key.offset >
1968 logical + map->stripe_len) {
1969 key.offset = logical + map->stripe_len -
1970 key.objectid;
1973 ret = scrub_extent(sdev, key.objectid, key.offset,
1974 key.objectid - logical + physical,
1975 flags, generation, mirror_num);
1976 if (ret)
1977 goto out;
1979 next:
1980 path->slots[0]++;
1982 btrfs_release_path(path);
1983 logical += increment;
1984 physical += map->stripe_len;
1985 spin_lock(&sdev->stat_lock);
1986 sdev->stat.last_physical = physical;
1987 spin_unlock(&sdev->stat_lock);
1989 /* push queued extents */
1990 scrub_submit(sdev);
1992 out:
1993 blk_finish_plug(&plug);
1994 btrfs_free_path(path);
1995 return ret < 0 ? ret : 0;
1998 static noinline_for_stack int scrub_chunk(struct scrub_dev *sdev,
1999 u64 chunk_tree, u64 chunk_objectid, u64 chunk_offset, u64 length,
2000 u64 dev_offset)
2002 struct btrfs_mapping_tree *map_tree =
2003 &sdev->dev->dev_root->fs_info->mapping_tree;
2004 struct map_lookup *map;
2005 struct extent_map *em;
2006 int i;
2007 int ret = -EINVAL;
2009 read_lock(&map_tree->map_tree.lock);
2010 em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
2011 read_unlock(&map_tree->map_tree.lock);
2013 if (!em)
2014 return -EINVAL;
2016 map = (struct map_lookup *)em->bdev;
2017 if (em->start != chunk_offset)
2018 goto out;
2020 if (em->len < length)
2021 goto out;
2023 for (i = 0; i < map->num_stripes; ++i) {
2024 if (map->stripes[i].dev == sdev->dev &&
2025 map->stripes[i].physical == dev_offset) {
2026 ret = scrub_stripe(sdev, map, i, chunk_offset, length);
2027 if (ret)
2028 goto out;
2031 out:
2032 free_extent_map(em);
2034 return ret;
2037 static noinline_for_stack
2038 int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end)
2040 struct btrfs_dev_extent *dev_extent = NULL;
2041 struct btrfs_path *path;
2042 struct btrfs_root *root = sdev->dev->dev_root;
2043 struct btrfs_fs_info *fs_info = root->fs_info;
2044 u64 length;
2045 u64 chunk_tree;
2046 u64 chunk_objectid;
2047 u64 chunk_offset;
2048 int ret;
2049 int slot;
2050 struct extent_buffer *l;
2051 struct btrfs_key key;
2052 struct btrfs_key found_key;
2053 struct btrfs_block_group_cache *cache;
2055 path = btrfs_alloc_path();
2056 if (!path)
2057 return -ENOMEM;
2059 path->reada = 2;
2060 path->search_commit_root = 1;
2061 path->skip_locking = 1;
2063 key.objectid = sdev->dev->devid;
2064 key.offset = 0ull;
2065 key.type = BTRFS_DEV_EXTENT_KEY;
2068 while (1) {
2069 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2070 if (ret < 0)
2071 break;
2072 if (ret > 0) {
2073 if (path->slots[0] >=
2074 btrfs_header_nritems(path->nodes[0])) {
2075 ret = btrfs_next_leaf(root, path);
2076 if (ret)
2077 break;
2081 l = path->nodes[0];
2082 slot = path->slots[0];
2084 btrfs_item_key_to_cpu(l, &found_key, slot);
2086 if (found_key.objectid != sdev->dev->devid)
2087 break;
2089 if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY)
2090 break;
2092 if (found_key.offset >= end)
2093 break;
2095 if (found_key.offset < key.offset)
2096 break;
2098 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
2099 length = btrfs_dev_extent_length(l, dev_extent);
2101 if (found_key.offset + length <= start) {
2102 key.offset = found_key.offset + length;
2103 btrfs_release_path(path);
2104 continue;
2107 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
2108 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
2109 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
2112 * get a reference on the corresponding block group to prevent
2113 * the chunk from going away while we scrub it
2115 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2116 if (!cache) {
2117 ret = -ENOENT;
2118 break;
2120 ret = scrub_chunk(sdev, chunk_tree, chunk_objectid,
2121 chunk_offset, length, found_key.offset);
2122 btrfs_put_block_group(cache);
2123 if (ret)
2124 break;
2126 key.offset = found_key.offset + length;
2127 btrfs_release_path(path);
2130 btrfs_free_path(path);
2133 * ret can still be 1 from search_slot or next_leaf,
2134 * that's not an error
2136 return ret < 0 ? ret : 0;
2139 static noinline_for_stack int scrub_supers(struct scrub_dev *sdev)
2141 int i;
2142 u64 bytenr;
2143 u64 gen;
2144 int ret;
2145 struct btrfs_device *device = sdev->dev;
2146 struct btrfs_root *root = device->dev_root;
2148 if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
2149 return -EIO;
2151 gen = root->fs_info->last_trans_committed;
2153 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
2154 bytenr = btrfs_sb_offset(i);
2155 if (bytenr + BTRFS_SUPER_INFO_SIZE > device->total_bytes)
2156 break;
2158 ret = scrub_pages(sdev, bytenr, BTRFS_SUPER_INFO_SIZE, bytenr,
2159 BTRFS_EXTENT_FLAG_SUPER, gen, i, NULL, 1);
2160 if (ret)
2161 return ret;
2163 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
2165 return 0;
2169 * get a reference count on fs_info->scrub_workers. start worker if necessary
2171 static noinline_for_stack int scrub_workers_get(struct btrfs_root *root)
2173 struct btrfs_fs_info *fs_info = root->fs_info;
2174 int ret = 0;
2176 mutex_lock(&fs_info->scrub_lock);
2177 if (fs_info->scrub_workers_refcnt == 0) {
2178 btrfs_init_workers(&fs_info->scrub_workers, "scrub",
2179 fs_info->thread_pool_size, &fs_info->generic_worker);
2180 fs_info->scrub_workers.idle_thresh = 4;
2181 ret = btrfs_start_workers(&fs_info->scrub_workers);
2182 if (ret)
2183 goto out;
2185 ++fs_info->scrub_workers_refcnt;
2186 out:
2187 mutex_unlock(&fs_info->scrub_lock);
2189 return ret;
2192 static noinline_for_stack void scrub_workers_put(struct btrfs_root *root)
2194 struct btrfs_fs_info *fs_info = root->fs_info;
2196 mutex_lock(&fs_info->scrub_lock);
2197 if (--fs_info->scrub_workers_refcnt == 0)
2198 btrfs_stop_workers(&fs_info->scrub_workers);
2199 WARN_ON(fs_info->scrub_workers_refcnt < 0);
2200 mutex_unlock(&fs_info->scrub_lock);
2204 int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end,
2205 struct btrfs_scrub_progress *progress, int readonly)
2207 struct scrub_dev *sdev;
2208 struct btrfs_fs_info *fs_info = root->fs_info;
2209 int ret;
2210 struct btrfs_device *dev;
2212 if (btrfs_fs_closing(root->fs_info))
2213 return -EINVAL;
2216 * check some assumptions
2218 if (root->nodesize != root->leafsize) {
2219 printk(KERN_ERR
2220 "btrfs_scrub: size assumption nodesize == leafsize (%d == %d) fails\n",
2221 root->nodesize, root->leafsize);
2222 return -EINVAL;
2225 if (root->nodesize > BTRFS_STRIPE_LEN) {
2227 * in this case scrub is unable to calculate the checksum
2228 * the way scrub is implemented. Do not handle this
2229 * situation at all because it won't ever happen.
2231 printk(KERN_ERR
2232 "btrfs_scrub: size assumption nodesize <= BTRFS_STRIPE_LEN (%d <= %d) fails\n",
2233 root->nodesize, BTRFS_STRIPE_LEN);
2234 return -EINVAL;
2237 if (root->sectorsize != PAGE_SIZE) {
2238 /* not supported for data w/o checksums */
2239 printk(KERN_ERR
2240 "btrfs_scrub: size assumption sectorsize != PAGE_SIZE (%d != %lld) fails\n",
2241 root->sectorsize, (unsigned long long)PAGE_SIZE);
2242 return -EINVAL;
2245 ret = scrub_workers_get(root);
2246 if (ret)
2247 return ret;
2249 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2250 dev = btrfs_find_device(root, devid, NULL, NULL);
2251 if (!dev || dev->missing) {
2252 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2253 scrub_workers_put(root);
2254 return -ENODEV;
2256 mutex_lock(&fs_info->scrub_lock);
2258 if (!dev->in_fs_metadata) {
2259 mutex_unlock(&fs_info->scrub_lock);
2260 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2261 scrub_workers_put(root);
2262 return -ENODEV;
2265 if (dev->scrub_device) {
2266 mutex_unlock(&fs_info->scrub_lock);
2267 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2268 scrub_workers_put(root);
2269 return -EINPROGRESS;
2271 sdev = scrub_setup_dev(dev);
2272 if (IS_ERR(sdev)) {
2273 mutex_unlock(&fs_info->scrub_lock);
2274 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2275 scrub_workers_put(root);
2276 return PTR_ERR(sdev);
2278 sdev->readonly = readonly;
2279 dev->scrub_device = sdev;
2281 atomic_inc(&fs_info->scrubs_running);
2282 mutex_unlock(&fs_info->scrub_lock);
2283 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2285 down_read(&fs_info->scrub_super_lock);
2286 ret = scrub_supers(sdev);
2287 up_read(&fs_info->scrub_super_lock);
2289 if (!ret)
2290 ret = scrub_enumerate_chunks(sdev, start, end);
2292 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
2293 atomic_dec(&fs_info->scrubs_running);
2294 wake_up(&fs_info->scrub_pause_wait);
2296 wait_event(sdev->list_wait, atomic_read(&sdev->fixup_cnt) == 0);
2298 if (progress)
2299 memcpy(progress, &sdev->stat, sizeof(*progress));
2301 mutex_lock(&fs_info->scrub_lock);
2302 dev->scrub_device = NULL;
2303 mutex_unlock(&fs_info->scrub_lock);
2305 scrub_free_dev(sdev);
2306 scrub_workers_put(root);
2308 return ret;
2311 void btrfs_scrub_pause(struct btrfs_root *root)
2313 struct btrfs_fs_info *fs_info = root->fs_info;
2315 mutex_lock(&fs_info->scrub_lock);
2316 atomic_inc(&fs_info->scrub_pause_req);
2317 while (atomic_read(&fs_info->scrubs_paused) !=
2318 atomic_read(&fs_info->scrubs_running)) {
2319 mutex_unlock(&fs_info->scrub_lock);
2320 wait_event(fs_info->scrub_pause_wait,
2321 atomic_read(&fs_info->scrubs_paused) ==
2322 atomic_read(&fs_info->scrubs_running));
2323 mutex_lock(&fs_info->scrub_lock);
2325 mutex_unlock(&fs_info->scrub_lock);
2328 void btrfs_scrub_continue(struct btrfs_root *root)
2330 struct btrfs_fs_info *fs_info = root->fs_info;
2332 atomic_dec(&fs_info->scrub_pause_req);
2333 wake_up(&fs_info->scrub_pause_wait);
2336 void btrfs_scrub_pause_super(struct btrfs_root *root)
2338 down_write(&root->fs_info->scrub_super_lock);
2341 void btrfs_scrub_continue_super(struct btrfs_root *root)
2343 up_write(&root->fs_info->scrub_super_lock);
2346 int __btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
2349 mutex_lock(&fs_info->scrub_lock);
2350 if (!atomic_read(&fs_info->scrubs_running)) {
2351 mutex_unlock(&fs_info->scrub_lock);
2352 return -ENOTCONN;
2355 atomic_inc(&fs_info->scrub_cancel_req);
2356 while (atomic_read(&fs_info->scrubs_running)) {
2357 mutex_unlock(&fs_info->scrub_lock);
2358 wait_event(fs_info->scrub_pause_wait,
2359 atomic_read(&fs_info->scrubs_running) == 0);
2360 mutex_lock(&fs_info->scrub_lock);
2362 atomic_dec(&fs_info->scrub_cancel_req);
2363 mutex_unlock(&fs_info->scrub_lock);
2365 return 0;
2368 int btrfs_scrub_cancel(struct btrfs_root *root)
2370 return __btrfs_scrub_cancel(root->fs_info);
2373 int btrfs_scrub_cancel_dev(struct btrfs_root *root, struct btrfs_device *dev)
2375 struct btrfs_fs_info *fs_info = root->fs_info;
2376 struct scrub_dev *sdev;
2378 mutex_lock(&fs_info->scrub_lock);
2379 sdev = dev->scrub_device;
2380 if (!sdev) {
2381 mutex_unlock(&fs_info->scrub_lock);
2382 return -ENOTCONN;
2384 atomic_inc(&sdev->cancel_req);
2385 while (dev->scrub_device) {
2386 mutex_unlock(&fs_info->scrub_lock);
2387 wait_event(fs_info->scrub_pause_wait,
2388 dev->scrub_device == NULL);
2389 mutex_lock(&fs_info->scrub_lock);
2391 mutex_unlock(&fs_info->scrub_lock);
2393 return 0;
2396 int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid)
2398 struct btrfs_fs_info *fs_info = root->fs_info;
2399 struct btrfs_device *dev;
2400 int ret;
2403 * we have to hold the device_list_mutex here so the device
2404 * does not go away in cancel_dev. FIXME: find a better solution
2406 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2407 dev = btrfs_find_device(root, devid, NULL, NULL);
2408 if (!dev) {
2409 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2410 return -ENODEV;
2412 ret = btrfs_scrub_cancel_dev(root, dev);
2413 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2415 return ret;
2418 int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
2419 struct btrfs_scrub_progress *progress)
2421 struct btrfs_device *dev;
2422 struct scrub_dev *sdev = NULL;
2424 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2425 dev = btrfs_find_device(root, devid, NULL, NULL);
2426 if (dev)
2427 sdev = dev->scrub_device;
2428 if (sdev)
2429 memcpy(progress, &sdev->stat, sizeof(*progress));
2430 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2432 return dev ? (sdev ? 0 : -ENOTCONN) : -ENODEV;