From: Qu Wenruo wqu@suse.com
[ Upstream commit 8df507cbb5952719353c912a021b66c27641e90c ]
[BUG] For the following file layout, scrub will not be able to repair all these two repairable error, but in fact make one corruption even unrepairable:
inode offset 0 4k 8K Mirror 1 |XXXXXX| | Mirror 2 | |XXXXXX|
[CAUSE] The root cause is the hard coded PAGE_SIZE, which makes scrub repair to go crazy for subpage.
For above case, when reading the first sector, we use PAGE_SIZE other than sectorsize to read, which makes us to read the full range [0, 64K). In fact, after 8K there may be no data at all, we can just get some garbage.
Then when doing the repair, we also writeback a full page from mirror 2, this means, we will also writeback the corrupted data in mirror 2 back to mirror 1, leaving the range [4K, 8K) unrepairable.
[FIX] This patch will modify the following PAGE_SIZE use with sectorsize:
- scrub_print_warning_inode() Remove the min() and replace PAGE_SIZE with sectorsize. The min() makes no sense, as csum is done for the full sector with padding.
This fixes a bug that subpage report extra length like: checksum error at logical 298844160 on dev /dev/mapper/arm_nvme-test, physical 575668224, root 5, inode 257, offset 0, length 12288, links 1 (path: file)
Where the error is only 1 sector.
- scrub_handle_errored_block() Comments with PAGE|page involved, all changed to sector.
- scrub_setup_recheck_block() - scrub_repair_page_from_good_copy() - scrub_add_page_to_wr_bio() - scrub_wr_submit() - scrub_add_page_to_rd_bio() - scrub_block_complete() Replace PAGE_SIZE with sectorsize. This solves several problems where we read/write extra range for subpage case.
RAID56 code is excluded intentionally, as RAID56 has extra PAGE_SIZE usage, and is not really safe enough. Thus we will reject RAID56 for subpage in later commit.
Signed-off-by: Qu Wenruo wqu@suse.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/scrub.c | 82 +++++++++++++++++++++++++----------------------- 1 file changed, 42 insertions(+), 40 deletions(-)
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 485cda3eb8d7..6af901539ef2 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -626,7 +626,6 @@ static noinline_for_stack struct scrub_ctx *scrub_setup_ctx( static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root, void *warn_ctx) { - u64 isize; u32 nlink; int ret; int i; @@ -662,7 +661,6 @@ static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root, eb = swarn->path->nodes[0]; inode_item = btrfs_item_ptr(eb, swarn->path->slots[0], struct btrfs_inode_item); - isize = btrfs_inode_size(eb, inode_item); nlink = btrfs_inode_nlink(eb, inode_item); btrfs_release_path(swarn->path);
@@ -691,12 +689,12 @@ static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root, */ for (i = 0; i < ipath->fspath->elem_cnt; ++i) btrfs_warn_in_rcu(fs_info, -"%s at logical %llu on dev %s, physical %llu, root %llu, inode %llu, offset %llu, length %llu, links %u (path: %s)", +"%s at logical %llu on dev %s, physical %llu, root %llu, inode %llu, offset %llu, length %u, links %u (path: %s)", swarn->errstr, swarn->logical, rcu_str_deref(swarn->dev->name), swarn->physical, root, inum, offset, - min(isize - offset, (u64)PAGE_SIZE), nlink, + fs_info->sectorsize, nlink, (char *)(unsigned long)ipath->fspath->val[i]);
btrfs_put_root(local_root); @@ -885,25 +883,25 @@ static int scrub_handle_errored_block(struct scrub_block *sblock_to_check) * read all mirrors one after the other. This includes to * re-read the extent or metadata block that failed (that was * the cause that this fixup code is called) another time, - * page by page this time in order to know which pages + * sector by sector this time in order to know which sectors * caused I/O errors and which ones are good (for all mirrors). * It is the goal to handle the situation when more than one * mirror contains I/O errors, but the errors do not * overlap, i.e. the data can be repaired by selecting the - * pages from those mirrors without I/O error on the - * particular pages. One example (with blocks >= 2 * PAGE_SIZE) - * would be that mirror #1 has an I/O error on the first page, - * the second page is good, and mirror #2 has an I/O error on - * the second page, but the first page is good. - * Then the first page of the first mirror can be repaired by - * taking the first page of the second mirror, and the - * second page of the second mirror can be repaired by - * copying the contents of the 2nd page of the 1st mirror. - * One more note: if the pages of one mirror contain I/O + * sectors from those mirrors without I/O error on the + * particular sectors. One example (with blocks >= 2 * sectorsize) + * would be that mirror #1 has an I/O error on the first sector, + * the second sector is good, and mirror #2 has an I/O error on + * the second sector, but the first sector is good. + * Then the first sector of the first mirror can be repaired by + * taking the first sector of the second mirror, and the + * second sector of the second mirror can be repaired by + * copying the contents of the 2nd sector of the 1st mirror. + * One more note: if the sectors of one mirror contain I/O * errors, the checksum cannot be verified. In order to get * the best data for repairing, the first attempt is to find * a mirror without I/O errors and with a validated checksum. - * Only if this is not possible, the pages are picked from + * Only if this is not possible, the sectors are picked from * mirrors with I/O errors without considering the checksum. * If the latter is the case, at the end, the checksum of the * repaired area is verified in order to correctly maintain @@ -1060,26 +1058,26 @@ static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
/* * In case of I/O errors in the area that is supposed to be - * repaired, continue by picking good copies of those pages. - * Select the good pages from mirrors to rewrite bad pages from + * repaired, continue by picking good copies of those sectors. + * Select the good sectors from mirrors to rewrite bad sectors from * the area to fix. Afterwards verify the checksum of the block * that is supposed to be repaired. This verification step is * only done for the purpose of statistic counting and for the * final scrub report, whether errors remain. * A perfect algorithm could make use of the checksum and try - * all possible combinations of pages from the different mirrors + * all possible combinations of sectors from the different mirrors * until the checksum verification succeeds. For example, when - * the 2nd page of mirror #1 faces I/O errors, and the 2nd page + * the 2nd sector of mirror #1 faces I/O errors, and the 2nd sector * of mirror #2 is readable but the final checksum test fails, - * then the 2nd page of mirror #3 could be tried, whether now + * then the 2nd sector of mirror #3 could be tried, whether now * the final checksum succeeds. But this would be a rare * exception and is therefore not implemented. At least it is * avoided that the good copy is overwritten. * A more useful improvement would be to pick the sectors * without I/O error based on sector sizes (512 bytes on legacy - * disks) instead of on PAGE_SIZE. Then maybe 512 byte of one + * disks) instead of on sectorsize. Then maybe 512 byte of one * mirror could be repaired by taking 512 byte of a different - * mirror, even if other 512 byte sectors in the same PAGE_SIZE + * mirror, even if other 512 byte sectors in the same sectorsize * area are unreadable. */ success = 1; @@ -1260,7 +1258,7 @@ static int scrub_setup_recheck_block(struct scrub_block *original_sblock, { struct scrub_ctx *sctx = original_sblock->sctx; struct btrfs_fs_info *fs_info = sctx->fs_info; - u64 length = original_sblock->page_count * PAGE_SIZE; + u64 length = original_sblock->page_count * fs_info->sectorsize; u64 logical = original_sblock->pagev[0]->logical; u64 generation = original_sblock->pagev[0]->generation; u64 flags = original_sblock->pagev[0]->flags; @@ -1283,13 +1281,13 @@ static int scrub_setup_recheck_block(struct scrub_block *original_sblock, */
while (length > 0) { - sublen = min_t(u64, length, PAGE_SIZE); + sublen = min_t(u64, length, fs_info->sectorsize); mapped_length = sublen; bbio = NULL;
/* - * with a length of PAGE_SIZE, each returned stripe - * represents one mirror + * With a length of sectorsize, each returned stripe represents + * one mirror */ btrfs_bio_counter_inc_blocked(fs_info); ret = btrfs_map_sblock(fs_info, BTRFS_MAP_GET_READ_MIRRORS, @@ -1480,7 +1478,7 @@ static void scrub_recheck_block(struct btrfs_fs_info *fs_info, bio = btrfs_io_bio_alloc(1); bio_set_dev(bio, spage->dev->bdev);
- bio_add_page(bio, spage->page, PAGE_SIZE, 0); + bio_add_page(bio, spage->page, fs_info->sectorsize, 0); bio->bi_iter.bi_sector = spage->physical >> 9; bio->bi_opf = REQ_OP_READ;
@@ -1544,6 +1542,7 @@ static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad, struct scrub_page *spage_bad = sblock_bad->pagev[page_num]; struct scrub_page *spage_good = sblock_good->pagev[page_num]; struct btrfs_fs_info *fs_info = sblock_bad->sctx->fs_info; + const u32 sectorsize = fs_info->sectorsize;
BUG_ON(spage_bad->page == NULL); BUG_ON(spage_good->page == NULL); @@ -1563,8 +1562,8 @@ static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad, bio->bi_iter.bi_sector = spage_bad->physical >> 9; bio->bi_opf = REQ_OP_WRITE;
- ret = bio_add_page(bio, spage_good->page, PAGE_SIZE, 0); - if (PAGE_SIZE != ret) { + ret = bio_add_page(bio, spage_good->page, sectorsize, 0); + if (ret != sectorsize) { bio_put(bio); return -EIO; } @@ -1642,6 +1641,7 @@ static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx, { struct scrub_bio *sbio; int ret; + const u32 sectorsize = sctx->fs_info->sectorsize;
mutex_lock(&sctx->wr_lock); again: @@ -1681,16 +1681,16 @@ static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx, bio->bi_iter.bi_sector = sbio->physical >> 9; bio->bi_opf = REQ_OP_WRITE; sbio->status = 0; - } else if (sbio->physical + sbio->page_count * PAGE_SIZE != + } else if (sbio->physical + sbio->page_count * sectorsize != spage->physical_for_dev_replace || - sbio->logical + sbio->page_count * PAGE_SIZE != + sbio->logical + sbio->page_count * sectorsize != spage->logical) { scrub_wr_submit(sctx); goto again; }
- ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0); - if (ret != PAGE_SIZE) { + ret = bio_add_page(sbio->bio, spage->page, sectorsize, 0); + if (ret != sectorsize) { if (sbio->page_count < 1) { bio_put(sbio->bio); sbio->bio = NULL; @@ -1729,7 +1729,8 @@ static void scrub_wr_submit(struct scrub_ctx *sctx) btrfsic_submit_bio(sbio->bio);
if (btrfs_is_zoned(sctx->fs_info)) - sctx->write_pointer = sbio->physical + sbio->page_count * PAGE_SIZE; + sctx->write_pointer = sbio->physical + sbio->page_count * + sctx->fs_info->sectorsize; }
static void scrub_wr_bio_end_io(struct bio *bio) @@ -2006,6 +2007,7 @@ static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx, { struct scrub_block *sblock = spage->sblock; struct scrub_bio *sbio; + const u32 sectorsize = sctx->fs_info->sectorsize; int ret;
again: @@ -2044,9 +2046,9 @@ static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx, bio->bi_iter.bi_sector = sbio->physical >> 9; bio->bi_opf = REQ_OP_READ; sbio->status = 0; - } else if (sbio->physical + sbio->page_count * PAGE_SIZE != + } else if (sbio->physical + sbio->page_count * sectorsize != spage->physical || - sbio->logical + sbio->page_count * PAGE_SIZE != + sbio->logical + sbio->page_count * sectorsize != spage->logical || sbio->dev != spage->dev) { scrub_submit(sctx); @@ -2054,8 +2056,8 @@ static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx, }
sbio->pagev[sbio->page_count] = spage; - ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0); - if (ret != PAGE_SIZE) { + ret = bio_add_page(sbio->bio, spage->page, sectorsize, 0); + if (ret != sectorsize) { if (sbio->page_count < 1) { bio_put(sbio->bio); sbio->bio = NULL; @@ -2398,7 +2400,7 @@ static void scrub_block_complete(struct scrub_block *sblock) if (sblock->sparity && corrupted && !sblock->data_corrected) { u64 start = sblock->pagev[0]->logical; u64 end = sblock->pagev[sblock->page_count - 1]->logical + - PAGE_SIZE; + sblock->sctx->fs_info->sectorsize;
ASSERT(end - start <= U32_MAX); scrub_parity_mark_sectors_error(sblock->sparity,