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>
24 #include "ordered-data.h"
25 #include "transaction.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
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
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 */
51 struct scrub_block *sblock;
53 struct block_device *bdev;
54 u64 flags; /* extent flags */
59 unsigned int mirror_num:8;
60 unsigned int have_csum:1;
61 unsigned int io_error:1;
63 u8 csum[BTRFS_CSUM_SIZE];
68 struct scrub_dev *sdev;
73 struct scrub_page *pagev[SCRUB_PAGES_PER_BIO];
76 struct btrfs_work work;
80 struct scrub_page pagev[SCRUB_MAX_PAGES_PER_BLOCK];
82 atomic_t outstanding_pages;
83 atomic_t ref_count; /* free mem on transition to zero */
84 struct scrub_dev *sdev;
86 unsigned int header_error:1;
87 unsigned int checksum_error:1;
88 unsigned int no_io_error_seen:1;
93 struct scrub_bio *bios[SCRUB_BIOS_PER_DEV];
94 struct btrfs_device *dev;
100 wait_queue_head_t list_wait;
102 struct list_head csum_list;
105 int pages_per_bio; /* <= SCRUB_PAGES_PER_BIO */
112 struct btrfs_scrub_progress stat;
113 spinlock_t stat_lock;
116 struct scrub_fixup_nodatasum {
117 struct scrub_dev *sdev;
119 struct btrfs_root *root;
120 struct btrfs_work work;
124 struct scrub_warning {
125 struct btrfs_path *path;
126 u64 extent_item_size;
132 struct btrfs_device *dev;
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,
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,
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,
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);
185 static noinline_for_stack void scrub_free_dev(struct scrub_dev *sdev)
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);
204 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
205 struct scrub_bio *sbio = sdev->bios[i];
212 scrub_free_csums(sdev);
216 static noinline_for_stack
217 struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
219 struct scrub_dev *sdev;
221 struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
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);
230 sdev->pages_per_bio = pages_per_bio;
232 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
233 struct scrub_bio *sbio;
235 sbio = kzalloc(sizeof(*sbio), GFP_NOFS);
238 sdev->bios[i] = sbio;
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;
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);
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)
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);
293 ret = inode_item_info(inum, 0, local_root, swarn->path);
295 btrfs_release_path(swarn->path);
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);
308 ret = PTR_ERR(ipath);
312 ret = paths_from_inode(inum, ipath);
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]);
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);
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;
357 unsigned long ptr = 0;
358 const int bufsize = 4096;
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;
370 swarn.msg_bufsize = bufsize;
371 swarn.scratch_bufsize = bufsize;
373 if (!path || !swarn.scratch_buf || !swarn.msg_buf)
376 ret = extent_from_logical(fs_info, swarn.logical, path, &found_key);
380 extent_item_pos = swarn.logical - found_key.objectid;
381 swarn.extent_item_size = found_key.offset;
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) {
390 ret = tree_backref_for_extent(&ptr, eb, ei, item_size,
391 &ref_root, &ref_level);
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);
403 iterate_extent_inodes(fs_info, path, found_key.objectid,
405 scrub_print_warning_inode, &swarn);
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;
418 struct scrub_fixup_nodatasum *fixup = ctx;
421 struct btrfs_key key;
422 struct inode *inode = NULL;
423 u64 end = offset + PAGE_SIZE - 1;
424 struct btrfs_root *local_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;
436 inode = btrfs_iget(fixup->root->fs_info->sb, &key, local_root, NULL);
438 return PTR_ERR(inode);
440 index = offset >> PAGE_CACHE_SHIFT;
442 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
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.
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,
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);
485 /* set_extent_bits should give proper error */
492 ret = extent_read_full_page(&BTRFS_I(inode)->io_tree, page,
495 wait_on_page_locked(page);
497 corrected = !test_range_bit(&BTRFS_I(inode)->io_tree, offset,
498 end, EXTENT_DAMAGED, 0, NULL);
500 clear_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
501 EXTENT_DAMAGED, GFP_NOFS);
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
524 static void scrub_fixup_nodatasum(struct btrfs_work *work)
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);
536 fs_info = fixup->root->fs_info;
538 path = btrfs_alloc_path();
540 spin_lock(&sdev->stat_lock);
541 ++sdev->stat.malloc_errors;
542 spin_unlock(&sdev->stat_lock);
547 trans = btrfs_join_transaction(fixup->root);
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
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
562 ret = iterate_inodes_from_logical(fixup->logical, fixup->root->fs_info,
563 path, scrub_fixup_readpage,
571 spin_lock(&sdev->stat_lock);
572 ++sdev->stat.corrected_errors;
573 spin_unlock(&sdev->stat_lock);
576 if (trans && !IS_ERR(trans))
577 btrfs_end_transaction(trans, fixup->root);
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);
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
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;
615 unsigned int failed_mirror_index;
616 unsigned int is_metadata;
617 unsigned int have_csum;
619 struct scrub_block *sblocks_for_recheck; /* holds one for each mirror */
620 struct scrub_block *sblock_bad;
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
669 sblocks_for_recheck = kzalloc(BTRFS_MAX_MIRRORS *
670 sizeof(*sblocks_for_recheck),
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);
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);
685 spin_lock(&sdev->stat_lock);
686 sdev->stat.read_errors++;
687 sdev->stat.uncorrectable_errors++;
688 spin_unlock(&sdev->stat_lock);
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);
698 spin_lock(&sdev->stat_lock);
699 sdev->stat.read_errors++;
700 sdev->stat.uncorrectable_errors++;
701 spin_unlock(&sdev->stat_lock);
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
715 spin_lock(&sdev->stat_lock);
716 sdev->stat.unverified_errors++;
717 spin_unlock(&sdev->stat_lock);
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",
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
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);
784 * now build and submit the bios for the other mirrors, check
787 for (mirror_index = 0;
788 mirror_index < BTRFS_MAX_MIRRORS &&
789 sblocks_for_recheck[mirror_index].page_count > 0;
791 if (mirror_index == failed_mirror_index)
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);
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;
820 struct scrub_block *sblock_other = sblocks_for_recheck +
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,
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;
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)
872 for (mirror_index = 0;
873 mirror_index < BTRFS_MAX_MIRRORS &&
874 sblocks_for_recheck[mirror_index].page_count > 0;
876 struct scrub_block *sblock_other = sblocks_for_recheck +
878 struct scrub_page *page_other = sblock_other->pagev +
881 if (!page_other->io_error) {
882 ret = scrub_repair_page_from_good_copy(
883 sblock_bad, sblock_other, page_num, 0);
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 */
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
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;
916 goto did_not_correct_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);
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);
937 if (sblocks_for_recheck) {
938 for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS;
940 struct scrub_block *sblock = sblocks_for_recheck +
944 for (page_index = 0; page_index < SCRUB_PAGES_PER_BIO;
946 if (sblock->pagev[page_index].page)
948 sblock->pagev[page_index].page);
950 kfree(sblocks_for_recheck);
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)
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
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,
983 if (ret || !bbio || mapped_length < sublen) {
988 BUG_ON(page_index >= SCRUB_PAGES_PER_BIO);
989 for (mirror_index = 0; mirror_index < (int)bbio->num_stripes;
991 struct scrub_block *sblock;
992 struct scrub_page *page;
994 if (mirror_index >= BTRFS_MAX_MIRRORS)
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);
1005 spin_lock(&sdev->stat_lock);
1006 sdev->stat.malloc_errors++;
1007 spin_unlock(&sdev->stat_lock);
1010 sblock->page_count++;
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,
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++) {
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 bio->bi_bdev = page->bdev;
1048 bio->bi_sector = page->physical >> 9;
1049 bio->bi_end_io = scrub_complete_bio_end_io;
1050 bio->bi_private = &complete;
1052 ret = bio_add_page(bio, page->page, PAGE_SIZE, 0);
1053 if (PAGE_SIZE != ret) {
1057 btrfsic_submit_bio(READ, bio);
1059 /* this will also unplug the queue */
1060 wait_for_completion(&complete);
1062 page->io_error = !test_bit(BIO_UPTODATE, &bio->bi_flags);
1063 if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1064 sblock->no_io_error_seen = 0;
1068 if (sblock->no_io_error_seen)
1069 scrub_recheck_block_checksum(fs_info, sblock, is_metadata,
1070 have_csum, csum, generation,
1076 static void scrub_recheck_block_checksum(struct btrfs_fs_info *fs_info,
1077 struct scrub_block *sblock,
1078 int is_metadata, int have_csum,
1079 const u8 *csum, u64 generation,
1083 u8 calculated_csum[BTRFS_CSUM_SIZE];
1085 struct btrfs_root *root = fs_info->extent_root;
1086 void *mapped_buffer;
1088 BUG_ON(!sblock->pagev[0].page);
1090 struct btrfs_header *h;
1092 mapped_buffer = kmap_atomic(sblock->pagev[0].page, KM_USER0);
1093 h = (struct btrfs_header *)mapped_buffer;
1095 if (sblock->pagev[0].logical != le64_to_cpu(h->bytenr) ||
1096 generation != le64_to_cpu(h->generation) ||
1097 memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE) ||
1098 memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
1100 sblock->header_error = 1;
1106 mapped_buffer = kmap_atomic(sblock->pagev[0].page, KM_USER0);
1109 for (page_num = 0;;) {
1110 if (page_num == 0 && is_metadata)
1111 crc = btrfs_csum_data(root,
1112 ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE,
1113 crc, PAGE_SIZE - BTRFS_CSUM_SIZE);
1115 crc = btrfs_csum_data(root, mapped_buffer, crc,
1118 kunmap_atomic(mapped_buffer, KM_USER0);
1120 if (page_num >= sblock->page_count)
1122 BUG_ON(!sblock->pagev[page_num].page);
1124 mapped_buffer = kmap_atomic(sblock->pagev[page_num].page,
1128 btrfs_csum_final(crc, calculated_csum);
1129 if (memcmp(calculated_csum, csum, csum_size))
1130 sblock->checksum_error = 1;
1133 static void scrub_complete_bio_end_io(struct bio *bio, int err)
1135 complete((struct completion *)bio->bi_private);
1138 static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
1139 struct scrub_block *sblock_good,
1145 for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
1148 ret_sub = scrub_repair_page_from_good_copy(sblock_bad,
1159 static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
1160 struct scrub_block *sblock_good,
1161 int page_num, int force_write)
1163 struct scrub_page *page_bad = sblock_bad->pagev + page_num;
1164 struct scrub_page *page_good = sblock_good->pagev + page_num;
1166 BUG_ON(sblock_bad->pagev[page_num].page == NULL);
1167 BUG_ON(sblock_good->pagev[page_num].page == NULL);
1168 if (force_write || sblock_bad->header_error ||
1169 sblock_bad->checksum_error || page_bad->io_error) {
1172 DECLARE_COMPLETION_ONSTACK(complete);
1174 bio = bio_alloc(GFP_NOFS, 1);
1175 bio->bi_bdev = page_bad->bdev;
1176 bio->bi_sector = page_bad->physical >> 9;
1177 bio->bi_end_io = scrub_complete_bio_end_io;
1178 bio->bi_private = &complete;
1180 ret = bio_add_page(bio, page_good->page, PAGE_SIZE, 0);
1181 if (PAGE_SIZE != ret) {
1185 btrfsic_submit_bio(WRITE, bio);
1187 /* this will also unplug the queue */
1188 wait_for_completion(&complete);
1195 static void scrub_checksum(struct scrub_block *sblock)
1200 BUG_ON(sblock->page_count < 1);
1201 flags = sblock->pagev[0].flags;
1203 if (flags & BTRFS_EXTENT_FLAG_DATA)
1204 ret = scrub_checksum_data(sblock);
1205 else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1206 ret = scrub_checksum_tree_block(sblock);
1207 else if (flags & BTRFS_EXTENT_FLAG_SUPER)
1208 (void)scrub_checksum_super(sblock);
1212 scrub_handle_errored_block(sblock);
1215 static int scrub_checksum_data(struct scrub_block *sblock)
1217 struct scrub_dev *sdev = sblock->sdev;
1218 u8 csum[BTRFS_CSUM_SIZE];
1224 struct btrfs_root *root = sdev->dev->dev_root;
1228 BUG_ON(sblock->page_count < 1);
1229 if (!sblock->pagev[0].have_csum)
1232 on_disk_csum = sblock->pagev[0].csum;
1233 page = sblock->pagev[0].page;
1234 buffer = kmap_atomic(page, KM_USER0);
1236 len = sdev->sectorsize;
1239 u64 l = min_t(u64, len, PAGE_SIZE);
1241 crc = btrfs_csum_data(root, buffer, crc, l);
1242 kunmap_atomic(buffer, KM_USER0);
1247 BUG_ON(index >= sblock->page_count);
1248 BUG_ON(!sblock->pagev[index].page);
1249 page = sblock->pagev[index].page;
1250 buffer = kmap_atomic(page, KM_USER0);
1253 btrfs_csum_final(crc, csum);
1254 if (memcmp(csum, on_disk_csum, sdev->csum_size))
1258 spin_lock(&sdev->stat_lock);
1259 ++sdev->stat.csum_errors;
1260 spin_unlock(&sdev->stat_lock);
1266 static int scrub_checksum_tree_block(struct scrub_block *sblock)
1268 struct scrub_dev *sdev = sblock->sdev;
1269 struct btrfs_header *h;
1270 struct btrfs_root *root = sdev->dev->dev_root;
1271 struct btrfs_fs_info *fs_info = root->fs_info;
1272 u8 calculated_csum[BTRFS_CSUM_SIZE];
1273 u8 on_disk_csum[BTRFS_CSUM_SIZE];
1275 void *mapped_buffer;
1284 BUG_ON(sblock->page_count < 1);
1285 page = sblock->pagev[0].page;
1286 mapped_buffer = kmap_atomic(page, KM_USER0);
1287 h = (struct btrfs_header *)mapped_buffer;
1288 memcpy(on_disk_csum, h->csum, sdev->csum_size);
1291 * we don't use the getter functions here, as we
1292 * a) don't have an extent buffer and
1293 * b) the page is already kmapped
1296 if (sblock->pagev[0].logical != le64_to_cpu(h->bytenr))
1299 if (sblock->pagev[0].generation != le64_to_cpu(h->generation))
1302 if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
1305 if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
1309 BUG_ON(sdev->nodesize != sdev->leafsize);
1310 len = sdev->nodesize - BTRFS_CSUM_SIZE;
1311 mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
1312 p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
1315 u64 l = min_t(u64, len, mapped_size);
1317 crc = btrfs_csum_data(root, p, crc, l);
1318 kunmap_atomic(mapped_buffer, KM_USER0);
1323 BUG_ON(index >= sblock->page_count);
1324 BUG_ON(!sblock->pagev[index].page);
1325 page = sblock->pagev[index].page;
1326 mapped_buffer = kmap_atomic(page, KM_USER0);
1327 mapped_size = PAGE_SIZE;
1331 btrfs_csum_final(crc, calculated_csum);
1332 if (memcmp(calculated_csum, on_disk_csum, sdev->csum_size))
1335 if (crc_fail || fail) {
1336 spin_lock(&sdev->stat_lock);
1338 ++sdev->stat.csum_errors;
1340 ++sdev->stat.verify_errors;
1341 spin_unlock(&sdev->stat_lock);
1344 return fail || crc_fail;
1347 static int scrub_checksum_super(struct scrub_block *sblock)
1349 struct btrfs_super_block *s;
1350 struct scrub_dev *sdev = sblock->sdev;
1351 struct btrfs_root *root = sdev->dev->dev_root;
1352 struct btrfs_fs_info *fs_info = root->fs_info;
1353 u8 calculated_csum[BTRFS_CSUM_SIZE];
1354 u8 on_disk_csum[BTRFS_CSUM_SIZE];
1356 void *mapped_buffer;
1364 BUG_ON(sblock->page_count < 1);
1365 page = sblock->pagev[0].page;
1366 mapped_buffer = kmap_atomic(page, KM_USER0);
1367 s = (struct btrfs_super_block *)mapped_buffer;
1368 memcpy(on_disk_csum, s->csum, sdev->csum_size);
1370 if (sblock->pagev[0].logical != le64_to_cpu(s->bytenr))
1373 if (sblock->pagev[0].generation != le64_to_cpu(s->generation))
1376 if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
1379 len = BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE;
1380 mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
1381 p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
1384 u64 l = min_t(u64, len, mapped_size);
1386 crc = btrfs_csum_data(root, p, crc, l);
1387 kunmap_atomic(mapped_buffer, KM_USER0);
1392 BUG_ON(index >= sblock->page_count);
1393 BUG_ON(!sblock->pagev[index].page);
1394 page = sblock->pagev[index].page;
1395 mapped_buffer = kmap_atomic(page, KM_USER0);
1396 mapped_size = PAGE_SIZE;
1400 btrfs_csum_final(crc, calculated_csum);
1401 if (memcmp(calculated_csum, on_disk_csum, sdev->csum_size))
1406 * if we find an error in a super block, we just report it.
1407 * They will get written with the next transaction commit
1410 spin_lock(&sdev->stat_lock);
1411 ++sdev->stat.super_errors;
1412 spin_unlock(&sdev->stat_lock);
1418 static void scrub_block_get(struct scrub_block *sblock)
1420 atomic_inc(&sblock->ref_count);
1423 static void scrub_block_put(struct scrub_block *sblock)
1425 if (atomic_dec_and_test(&sblock->ref_count)) {
1428 for (i = 0; i < sblock->page_count; i++)
1429 if (sblock->pagev[i].page)
1430 __free_page(sblock->pagev[i].page);
1435 static void scrub_submit(struct scrub_dev *sdev)
1437 struct scrub_bio *sbio;
1439 if (sdev->curr == -1)
1442 sbio = sdev->bios[sdev->curr];
1444 atomic_inc(&sdev->in_flight);
1446 btrfsic_submit_bio(READ, sbio->bio);
1449 static int scrub_add_page_to_bio(struct scrub_dev *sdev,
1450 struct scrub_page *spage)
1452 struct scrub_block *sblock = spage->sblock;
1453 struct scrub_bio *sbio;
1458 * grab a fresh bio or wait for one to become available
1460 while (sdev->curr == -1) {
1461 spin_lock(&sdev->list_lock);
1462 sdev->curr = sdev->first_free;
1463 if (sdev->curr != -1) {
1464 sdev->first_free = sdev->bios[sdev->curr]->next_free;
1465 sdev->bios[sdev->curr]->next_free = -1;
1466 sdev->bios[sdev->curr]->page_count = 0;
1467 spin_unlock(&sdev->list_lock);
1469 spin_unlock(&sdev->list_lock);
1470 wait_event(sdev->list_wait, sdev->first_free != -1);
1473 sbio = sdev->bios[sdev->curr];
1474 if (sbio->page_count == 0) {
1477 sbio->physical = spage->physical;
1478 sbio->logical = spage->logical;
1481 bio = bio_alloc(GFP_NOFS, sdev->pages_per_bio);
1487 bio->bi_private = sbio;
1488 bio->bi_end_io = scrub_bio_end_io;
1489 bio->bi_bdev = sdev->dev->bdev;
1490 bio->bi_sector = spage->physical >> 9;
1492 } else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
1494 sbio->logical + sbio->page_count * PAGE_SIZE !=
1500 sbio->pagev[sbio->page_count] = spage;
1501 ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
1502 if (ret != PAGE_SIZE) {
1503 if (sbio->page_count < 1) {
1512 scrub_block_get(sblock); /* one for the added page */
1513 atomic_inc(&sblock->outstanding_pages);
1515 if (sbio->page_count == sdev->pages_per_bio)
1521 static int scrub_pages(struct scrub_dev *sdev, u64 logical, u64 len,
1522 u64 physical, u64 flags, u64 gen, int mirror_num,
1523 u8 *csum, int force)
1525 struct scrub_block *sblock;
1528 sblock = kzalloc(sizeof(*sblock), GFP_NOFS);
1530 spin_lock(&sdev->stat_lock);
1531 sdev->stat.malloc_errors++;
1532 spin_unlock(&sdev->stat_lock);
1536 /* one ref inside this function, plus one for each page later on */
1537 atomic_set(&sblock->ref_count, 1);
1538 sblock->sdev = sdev;
1539 sblock->no_io_error_seen = 1;
1541 for (index = 0; len > 0; index++) {
1542 struct scrub_page *spage = sblock->pagev + index;
1543 u64 l = min_t(u64, len, PAGE_SIZE);
1545 BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
1546 spage->page = alloc_page(GFP_NOFS);
1548 spin_lock(&sdev->stat_lock);
1549 sdev->stat.malloc_errors++;
1550 spin_unlock(&sdev->stat_lock);
1553 __free_page(sblock->pagev[index].page);
1558 spage->sblock = sblock;
1559 spage->bdev = sdev->dev->bdev;
1560 spage->flags = flags;
1561 spage->generation = gen;
1562 spage->logical = logical;
1563 spage->physical = physical;
1564 spage->mirror_num = mirror_num;
1566 spage->have_csum = 1;
1567 memcpy(spage->csum, csum, sdev->csum_size);
1569 spage->have_csum = 0;
1571 sblock->page_count++;
1577 BUG_ON(sblock->page_count == 0);
1578 for (index = 0; index < sblock->page_count; index++) {
1579 struct scrub_page *spage = sblock->pagev + index;
1582 ret = scrub_add_page_to_bio(sdev, spage);
1584 scrub_block_put(sblock);
1592 /* last one frees, either here or in bio completion for last page */
1593 scrub_block_put(sblock);
1597 static void scrub_bio_end_io(struct bio *bio, int err)
1599 struct scrub_bio *sbio = bio->bi_private;
1600 struct scrub_dev *sdev = sbio->sdev;
1601 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
1606 btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
1609 static void scrub_bio_end_io_worker(struct btrfs_work *work)
1611 struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
1612 struct scrub_dev *sdev = sbio->sdev;
1615 BUG_ON(sbio->page_count > SCRUB_PAGES_PER_BIO);
1617 for (i = 0; i < sbio->page_count; i++) {
1618 struct scrub_page *spage = sbio->pagev[i];
1620 spage->io_error = 1;
1621 spage->sblock->no_io_error_seen = 0;
1625 /* now complete the scrub_block items that have all pages completed */
1626 for (i = 0; i < sbio->page_count; i++) {
1627 struct scrub_page *spage = sbio->pagev[i];
1628 struct scrub_block *sblock = spage->sblock;
1630 if (atomic_dec_and_test(&sblock->outstanding_pages))
1631 scrub_block_complete(sblock);
1632 scrub_block_put(sblock);
1636 /* what is this good for??? */
1637 sbio->bio->bi_flags &= ~(BIO_POOL_MASK - 1);
1638 sbio->bio->bi_flags |= 1 << BIO_UPTODATE;
1639 sbio->bio->bi_phys_segments = 0;
1640 sbio->bio->bi_idx = 0;
1642 for (i = 0; i < sbio->page_count; i++) {
1644 bi = &sbio->bio->bi_io_vec[i];
1646 bi->bv_len = PAGE_SIZE;
1652 spin_lock(&sdev->list_lock);
1653 sbio->next_free = sdev->first_free;
1654 sdev->first_free = sbio->index;
1655 spin_unlock(&sdev->list_lock);
1656 atomic_dec(&sdev->in_flight);
1657 wake_up(&sdev->list_wait);
1660 static void scrub_block_complete(struct scrub_block *sblock)
1662 if (!sblock->no_io_error_seen)
1663 scrub_handle_errored_block(sblock);
1665 scrub_checksum(sblock);
1668 static int scrub_find_csum(struct scrub_dev *sdev, u64 logical, u64 len,
1671 struct btrfs_ordered_sum *sum = NULL;
1674 unsigned long num_sectors;
1676 while (!list_empty(&sdev->csum_list)) {
1677 sum = list_first_entry(&sdev->csum_list,
1678 struct btrfs_ordered_sum, list);
1679 if (sum->bytenr > logical)
1681 if (sum->bytenr + sum->len > logical)
1684 ++sdev->stat.csum_discards;
1685 list_del(&sum->list);
1692 num_sectors = sum->len / sdev->sectorsize;
1693 for (i = 0; i < num_sectors; ++i) {
1694 if (sum->sums[i].bytenr == logical) {
1695 memcpy(csum, &sum->sums[i].sum, sdev->csum_size);
1700 if (ret && i == num_sectors - 1) {
1701 list_del(&sum->list);
1707 /* scrub extent tries to collect up to 64 kB for each bio */
1708 static int scrub_extent(struct scrub_dev *sdev, u64 logical, u64 len,
1709 u64 physical, u64 flags, u64 gen, int mirror_num)
1712 u8 csum[BTRFS_CSUM_SIZE];
1715 if (flags & BTRFS_EXTENT_FLAG_DATA) {
1716 blocksize = sdev->sectorsize;
1717 spin_lock(&sdev->stat_lock);
1718 sdev->stat.data_extents_scrubbed++;
1719 sdev->stat.data_bytes_scrubbed += len;
1720 spin_unlock(&sdev->stat_lock);
1721 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1722 BUG_ON(sdev->nodesize != sdev->leafsize);
1723 blocksize = sdev->nodesize;
1724 spin_lock(&sdev->stat_lock);
1725 sdev->stat.tree_extents_scrubbed++;
1726 sdev->stat.tree_bytes_scrubbed += len;
1727 spin_unlock(&sdev->stat_lock);
1729 blocksize = sdev->sectorsize;
1734 u64 l = min_t(u64, len, blocksize);
1737 if (flags & BTRFS_EXTENT_FLAG_DATA) {
1738 /* push csums to sbio */
1739 have_csum = scrub_find_csum(sdev, logical, l, csum);
1741 ++sdev->stat.no_csum;
1743 ret = scrub_pages(sdev, logical, l, physical, flags, gen,
1744 mirror_num, have_csum ? csum : NULL, 0);
1754 static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
1755 struct map_lookup *map, int num, u64 base, u64 length)
1757 struct btrfs_path *path;
1758 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
1759 struct btrfs_root *root = fs_info->extent_root;
1760 struct btrfs_root *csum_root = fs_info->csum_root;
1761 struct btrfs_extent_item *extent;
1762 struct blk_plug plug;
1768 struct extent_buffer *l;
1769 struct btrfs_key key;
1774 struct reada_control *reada1;
1775 struct reada_control *reada2;
1776 struct btrfs_key key_start;
1777 struct btrfs_key key_end;
1779 u64 increment = map->stripe_len;
1784 do_div(nstripes, map->stripe_len);
1785 if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
1786 offset = map->stripe_len * num;
1787 increment = map->stripe_len * map->num_stripes;
1789 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1790 int factor = map->num_stripes / map->sub_stripes;
1791 offset = map->stripe_len * (num / map->sub_stripes);
1792 increment = map->stripe_len * factor;
1793 mirror_num = num % map->sub_stripes + 1;
1794 } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
1795 increment = map->stripe_len;
1796 mirror_num = num % map->num_stripes + 1;
1797 } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
1798 increment = map->stripe_len;
1799 mirror_num = num % map->num_stripes + 1;
1801 increment = map->stripe_len;
1805 path = btrfs_alloc_path();
1810 * work on commit root. The related disk blocks are static as
1811 * long as COW is applied. This means, it is save to rewrite
1812 * them to repair disk errors without any race conditions
1814 path->search_commit_root = 1;
1815 path->skip_locking = 1;
1818 * trigger the readahead for extent tree csum tree and wait for
1819 * completion. During readahead, the scrub is officially paused
1820 * to not hold off transaction commits
1822 logical = base + offset;
1824 wait_event(sdev->list_wait,
1825 atomic_read(&sdev->in_flight) == 0);
1826 atomic_inc(&fs_info->scrubs_paused);
1827 wake_up(&fs_info->scrub_pause_wait);
1829 /* FIXME it might be better to start readahead at commit root */
1830 key_start.objectid = logical;
1831 key_start.type = BTRFS_EXTENT_ITEM_KEY;
1832 key_start.offset = (u64)0;
1833 key_end.objectid = base + offset + nstripes * increment;
1834 key_end.type = BTRFS_EXTENT_ITEM_KEY;
1835 key_end.offset = (u64)0;
1836 reada1 = btrfs_reada_add(root, &key_start, &key_end);
1838 key_start.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
1839 key_start.type = BTRFS_EXTENT_CSUM_KEY;
1840 key_start.offset = logical;
1841 key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
1842 key_end.type = BTRFS_EXTENT_CSUM_KEY;
1843 key_end.offset = base + offset + nstripes * increment;
1844 reada2 = btrfs_reada_add(csum_root, &key_start, &key_end);
1846 if (!IS_ERR(reada1))
1847 btrfs_reada_wait(reada1);
1848 if (!IS_ERR(reada2))
1849 btrfs_reada_wait(reada2);
1851 mutex_lock(&fs_info->scrub_lock);
1852 while (atomic_read(&fs_info->scrub_pause_req)) {
1853 mutex_unlock(&fs_info->scrub_lock);
1854 wait_event(fs_info->scrub_pause_wait,
1855 atomic_read(&fs_info->scrub_pause_req) == 0);
1856 mutex_lock(&fs_info->scrub_lock);
1858 atomic_dec(&fs_info->scrubs_paused);
1859 mutex_unlock(&fs_info->scrub_lock);
1860 wake_up(&fs_info->scrub_pause_wait);
1863 * collect all data csums for the stripe to avoid seeking during
1864 * the scrub. This might currently (crc32) end up to be about 1MB
1866 blk_start_plug(&plug);
1869 * now find all extents for each stripe and scrub them
1871 logical = base + offset;
1872 physical = map->stripes[num].physical;
1874 for (i = 0; i < nstripes; ++i) {
1878 if (atomic_read(&fs_info->scrub_cancel_req) ||
1879 atomic_read(&sdev->cancel_req)) {
1884 * check to see if we have to pause
1886 if (atomic_read(&fs_info->scrub_pause_req)) {
1887 /* push queued extents */
1889 wait_event(sdev->list_wait,
1890 atomic_read(&sdev->in_flight) == 0);
1891 atomic_inc(&fs_info->scrubs_paused);
1892 wake_up(&fs_info->scrub_pause_wait);
1893 mutex_lock(&fs_info->scrub_lock);
1894 while (atomic_read(&fs_info->scrub_pause_req)) {
1895 mutex_unlock(&fs_info->scrub_lock);
1896 wait_event(fs_info->scrub_pause_wait,
1897 atomic_read(&fs_info->scrub_pause_req) == 0);
1898 mutex_lock(&fs_info->scrub_lock);
1900 atomic_dec(&fs_info->scrubs_paused);
1901 mutex_unlock(&fs_info->scrub_lock);
1902 wake_up(&fs_info->scrub_pause_wait);
1905 ret = btrfs_lookup_csums_range(csum_root, logical,
1906 logical + map->stripe_len - 1,
1907 &sdev->csum_list, 1);
1911 key.objectid = logical;
1912 key.type = BTRFS_EXTENT_ITEM_KEY;
1913 key.offset = (u64)0;
1915 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1919 ret = btrfs_previous_item(root, path, 0,
1920 BTRFS_EXTENT_ITEM_KEY);
1924 /* there's no smaller item, so stick with the
1926 btrfs_release_path(path);
1927 ret = btrfs_search_slot(NULL, root, &key,
1936 slot = path->slots[0];
1937 if (slot >= btrfs_header_nritems(l)) {
1938 ret = btrfs_next_leaf(root, path);
1946 btrfs_item_key_to_cpu(l, &key, slot);
1948 if (key.objectid + key.offset <= logical)
1951 if (key.objectid >= logical + map->stripe_len)
1954 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY)
1957 extent = btrfs_item_ptr(l, slot,
1958 struct btrfs_extent_item);
1959 flags = btrfs_extent_flags(l, extent);
1960 generation = btrfs_extent_generation(l, extent);
1962 if (key.objectid < logical &&
1963 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
1965 "btrfs scrub: tree block %llu spanning "
1966 "stripes, ignored. logical=%llu\n",
1967 (unsigned long long)key.objectid,
1968 (unsigned long long)logical);
1973 * trim extent to this stripe
1975 if (key.objectid < logical) {
1976 key.offset -= logical - key.objectid;
1977 key.objectid = logical;
1979 if (key.objectid + key.offset >
1980 logical + map->stripe_len) {
1981 key.offset = logical + map->stripe_len -
1985 ret = scrub_extent(sdev, key.objectid, key.offset,
1986 key.objectid - logical + physical,
1987 flags, generation, mirror_num);
1994 btrfs_release_path(path);
1995 logical += increment;
1996 physical += map->stripe_len;
1997 spin_lock(&sdev->stat_lock);
1998 sdev->stat.last_physical = physical;
1999 spin_unlock(&sdev->stat_lock);
2001 /* push queued extents */
2005 blk_finish_plug(&plug);
2006 btrfs_free_path(path);
2007 return ret < 0 ? ret : 0;
2010 static noinline_for_stack int scrub_chunk(struct scrub_dev *sdev,
2011 u64 chunk_tree, u64 chunk_objectid, u64 chunk_offset, u64 length,
2014 struct btrfs_mapping_tree *map_tree =
2015 &sdev->dev->dev_root->fs_info->mapping_tree;
2016 struct map_lookup *map;
2017 struct extent_map *em;
2021 read_lock(&map_tree->map_tree.lock);
2022 em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
2023 read_unlock(&map_tree->map_tree.lock);
2028 map = (struct map_lookup *)em->bdev;
2029 if (em->start != chunk_offset)
2032 if (em->len < length)
2035 for (i = 0; i < map->num_stripes; ++i) {
2036 if (map->stripes[i].dev == sdev->dev &&
2037 map->stripes[i].physical == dev_offset) {
2038 ret = scrub_stripe(sdev, map, i, chunk_offset, length);
2044 free_extent_map(em);
2049 static noinline_for_stack
2050 int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end)
2052 struct btrfs_dev_extent *dev_extent = NULL;
2053 struct btrfs_path *path;
2054 struct btrfs_root *root = sdev->dev->dev_root;
2055 struct btrfs_fs_info *fs_info = root->fs_info;
2062 struct extent_buffer *l;
2063 struct btrfs_key key;
2064 struct btrfs_key found_key;
2065 struct btrfs_block_group_cache *cache;
2067 path = btrfs_alloc_path();
2072 path->search_commit_root = 1;
2073 path->skip_locking = 1;
2075 key.objectid = sdev->dev->devid;
2077 key.type = BTRFS_DEV_EXTENT_KEY;
2081 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2085 if (path->slots[0] >=
2086 btrfs_header_nritems(path->nodes[0])) {
2087 ret = btrfs_next_leaf(root, path);
2094 slot = path->slots[0];
2096 btrfs_item_key_to_cpu(l, &found_key, slot);
2098 if (found_key.objectid != sdev->dev->devid)
2101 if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY)
2104 if (found_key.offset >= end)
2107 if (found_key.offset < key.offset)
2110 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
2111 length = btrfs_dev_extent_length(l, dev_extent);
2113 if (found_key.offset + length <= start) {
2114 key.offset = found_key.offset + length;
2115 btrfs_release_path(path);
2119 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
2120 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
2121 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
2124 * get a reference on the corresponding block group to prevent
2125 * the chunk from going away while we scrub it
2127 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2132 ret = scrub_chunk(sdev, chunk_tree, chunk_objectid,
2133 chunk_offset, length, found_key.offset);
2134 btrfs_put_block_group(cache);
2138 key.offset = found_key.offset + length;
2139 btrfs_release_path(path);
2142 btrfs_free_path(path);
2145 * ret can still be 1 from search_slot or next_leaf,
2146 * that's not an error
2148 return ret < 0 ? ret : 0;
2151 static noinline_for_stack int scrub_supers(struct scrub_dev *sdev)
2157 struct btrfs_device *device = sdev->dev;
2158 struct btrfs_root *root = device->dev_root;
2160 if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
2163 gen = root->fs_info->last_trans_committed;
2165 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
2166 bytenr = btrfs_sb_offset(i);
2167 if (bytenr + BTRFS_SUPER_INFO_SIZE > device->total_bytes)
2170 ret = scrub_pages(sdev, bytenr, BTRFS_SUPER_INFO_SIZE, bytenr,
2171 BTRFS_EXTENT_FLAG_SUPER, gen, i, NULL, 1);
2175 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
2181 * get a reference count on fs_info->scrub_workers. start worker if necessary
2183 static noinline_for_stack int scrub_workers_get(struct btrfs_root *root)
2185 struct btrfs_fs_info *fs_info = root->fs_info;
2188 mutex_lock(&fs_info->scrub_lock);
2189 if (fs_info->scrub_workers_refcnt == 0) {
2190 btrfs_init_workers(&fs_info->scrub_workers, "scrub",
2191 fs_info->thread_pool_size, &fs_info->generic_worker);
2192 fs_info->scrub_workers.idle_thresh = 4;
2193 ret = btrfs_start_workers(&fs_info->scrub_workers);
2197 ++fs_info->scrub_workers_refcnt;
2199 mutex_unlock(&fs_info->scrub_lock);
2204 static noinline_for_stack void scrub_workers_put(struct btrfs_root *root)
2206 struct btrfs_fs_info *fs_info = root->fs_info;
2208 mutex_lock(&fs_info->scrub_lock);
2209 if (--fs_info->scrub_workers_refcnt == 0)
2210 btrfs_stop_workers(&fs_info->scrub_workers);
2211 WARN_ON(fs_info->scrub_workers_refcnt < 0);
2212 mutex_unlock(&fs_info->scrub_lock);
2216 int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end,
2217 struct btrfs_scrub_progress *progress, int readonly)
2219 struct scrub_dev *sdev;
2220 struct btrfs_fs_info *fs_info = root->fs_info;
2222 struct btrfs_device *dev;
2224 if (btrfs_fs_closing(root->fs_info))
2228 * check some assumptions
2230 if (root->nodesize != root->leafsize) {
2232 "btrfs_scrub: size assumption nodesize == leafsize (%d == %d) fails\n",
2233 root->nodesize, root->leafsize);
2237 if (root->nodesize > BTRFS_STRIPE_LEN) {
2239 * in this case scrub is unable to calculate the checksum
2240 * the way scrub is implemented. Do not handle this
2241 * situation at all because it won't ever happen.
2244 "btrfs_scrub: size assumption nodesize <= BTRFS_STRIPE_LEN (%d <= %d) fails\n",
2245 root->nodesize, BTRFS_STRIPE_LEN);
2249 if (root->sectorsize != PAGE_SIZE) {
2250 /* not supported for data w/o checksums */
2252 "btrfs_scrub: size assumption sectorsize != PAGE_SIZE (%d != %lld) fails\n",
2253 root->sectorsize, (unsigned long long)PAGE_SIZE);
2257 ret = scrub_workers_get(root);
2261 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2262 dev = btrfs_find_device(root, devid, NULL, NULL);
2263 if (!dev || dev->missing) {
2264 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2265 scrub_workers_put(root);
2268 mutex_lock(&fs_info->scrub_lock);
2270 if (!dev->in_fs_metadata) {
2271 mutex_unlock(&fs_info->scrub_lock);
2272 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2273 scrub_workers_put(root);
2277 if (dev->scrub_device) {
2278 mutex_unlock(&fs_info->scrub_lock);
2279 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2280 scrub_workers_put(root);
2281 return -EINPROGRESS;
2283 sdev = scrub_setup_dev(dev);
2285 mutex_unlock(&fs_info->scrub_lock);
2286 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2287 scrub_workers_put(root);
2288 return PTR_ERR(sdev);
2290 sdev->readonly = readonly;
2291 dev->scrub_device = sdev;
2293 atomic_inc(&fs_info->scrubs_running);
2294 mutex_unlock(&fs_info->scrub_lock);
2295 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2297 down_read(&fs_info->scrub_super_lock);
2298 ret = scrub_supers(sdev);
2299 up_read(&fs_info->scrub_super_lock);
2302 ret = scrub_enumerate_chunks(sdev, start, end);
2304 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
2305 atomic_dec(&fs_info->scrubs_running);
2306 wake_up(&fs_info->scrub_pause_wait);
2308 wait_event(sdev->list_wait, atomic_read(&sdev->fixup_cnt) == 0);
2311 memcpy(progress, &sdev->stat, sizeof(*progress));
2313 mutex_lock(&fs_info->scrub_lock);
2314 dev->scrub_device = NULL;
2315 mutex_unlock(&fs_info->scrub_lock);
2317 scrub_free_dev(sdev);
2318 scrub_workers_put(root);
2323 void btrfs_scrub_pause(struct btrfs_root *root)
2325 struct btrfs_fs_info *fs_info = root->fs_info;
2327 mutex_lock(&fs_info->scrub_lock);
2328 atomic_inc(&fs_info->scrub_pause_req);
2329 while (atomic_read(&fs_info->scrubs_paused) !=
2330 atomic_read(&fs_info->scrubs_running)) {
2331 mutex_unlock(&fs_info->scrub_lock);
2332 wait_event(fs_info->scrub_pause_wait,
2333 atomic_read(&fs_info->scrubs_paused) ==
2334 atomic_read(&fs_info->scrubs_running));
2335 mutex_lock(&fs_info->scrub_lock);
2337 mutex_unlock(&fs_info->scrub_lock);
2340 void btrfs_scrub_continue(struct btrfs_root *root)
2342 struct btrfs_fs_info *fs_info = root->fs_info;
2344 atomic_dec(&fs_info->scrub_pause_req);
2345 wake_up(&fs_info->scrub_pause_wait);
2348 void btrfs_scrub_pause_super(struct btrfs_root *root)
2350 down_write(&root->fs_info->scrub_super_lock);
2353 void btrfs_scrub_continue_super(struct btrfs_root *root)
2355 up_write(&root->fs_info->scrub_super_lock);
2358 int __btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
2361 mutex_lock(&fs_info->scrub_lock);
2362 if (!atomic_read(&fs_info->scrubs_running)) {
2363 mutex_unlock(&fs_info->scrub_lock);
2367 atomic_inc(&fs_info->scrub_cancel_req);
2368 while (atomic_read(&fs_info->scrubs_running)) {
2369 mutex_unlock(&fs_info->scrub_lock);
2370 wait_event(fs_info->scrub_pause_wait,
2371 atomic_read(&fs_info->scrubs_running) == 0);
2372 mutex_lock(&fs_info->scrub_lock);
2374 atomic_dec(&fs_info->scrub_cancel_req);
2375 mutex_unlock(&fs_info->scrub_lock);
2380 int btrfs_scrub_cancel(struct btrfs_root *root)
2382 return __btrfs_scrub_cancel(root->fs_info);
2385 int btrfs_scrub_cancel_dev(struct btrfs_root *root, struct btrfs_device *dev)
2387 struct btrfs_fs_info *fs_info = root->fs_info;
2388 struct scrub_dev *sdev;
2390 mutex_lock(&fs_info->scrub_lock);
2391 sdev = dev->scrub_device;
2393 mutex_unlock(&fs_info->scrub_lock);
2396 atomic_inc(&sdev->cancel_req);
2397 while (dev->scrub_device) {
2398 mutex_unlock(&fs_info->scrub_lock);
2399 wait_event(fs_info->scrub_pause_wait,
2400 dev->scrub_device == NULL);
2401 mutex_lock(&fs_info->scrub_lock);
2403 mutex_unlock(&fs_info->scrub_lock);
2408 int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid)
2410 struct btrfs_fs_info *fs_info = root->fs_info;
2411 struct btrfs_device *dev;
2415 * we have to hold the device_list_mutex here so the device
2416 * does not go away in cancel_dev. FIXME: find a better solution
2418 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2419 dev = btrfs_find_device(root, devid, NULL, NULL);
2421 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2424 ret = btrfs_scrub_cancel_dev(root, dev);
2425 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2430 int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
2431 struct btrfs_scrub_progress *progress)
2433 struct btrfs_device *dev;
2434 struct scrub_dev *sdev = NULL;
2436 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2437 dev = btrfs_find_device(root, devid, NULL, NULL);
2439 sdev = dev->scrub_device;
2441 memcpy(progress, &sdev->stat, sizeof(*progress));
2442 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2444 return dev ? (sdev ? 0 : -ENOTCONN) : -ENODEV;