diff options
| author | Omar Sandoval <osandov@fb.com> | 2015-06-19 21:52:52 +0300 |
|---|---|---|
| committer | Chris Mason <clm@fb.com> | 2015-08-09 17:34:26 +0300 |
| commit | 4a770891d9ddf94df985ca438e78d355b8469247 (patch) | |
| tree | 76ed4ed34130103c9467142d2444bada3e1150ce /fs/btrfs | |
| parent | 73ff61dbe5edeb1799d7e91c8b0641f87feb75fa (diff) | |
| download | linux-4a770891d9ddf94df985ca438e78d355b8469247.tar.xz | |
Btrfs: fix parity scrub of RAID 5/6 with missing device
When testing the previous patch, Zhao Lei reported a similar bug when
attempting to scrub a degraded RAID 5/6 filesystem with a missing
device, leading to NULL pointer dereferences from the RAID 5/6 parity
scrubbing code.
The first cause was the same as in the previous patch: attempting to
call bio_add_page() on a missing block device. To fix this,
scrub_extent_for_parity() can just mark the sectors on the missing
device as errors instead of attempting to read from it.
Additionally, the code uses scrub_remap_extent() to map the extent of
the corresponding data stripe, but the extent wasn't already mapped. If
scrub_remap_extent() finds a missing block device, it doesn't initialize
extent_dev, so we're left with a NULL struct btrfs_device. The solution
is to use btrfs_map_block() directly.
Reported-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/scrub.c | 26 |
1 files changed, 22 insertions, 4 deletions
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 6bce7f2ff805..c69c75e7b841 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -2696,6 +2696,11 @@ static int scrub_extent_for_parity(struct scrub_parity *sparity, u8 csum[BTRFS_CSUM_SIZE]; u32 blocksize; + if (dev->missing) { + scrub_parity_mark_sectors_error(sparity, logical, len); + return 0; + } + if (flags & BTRFS_EXTENT_FLAG_DATA) { blocksize = sctx->sectorsize; } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { @@ -2905,6 +2910,7 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx, struct btrfs_root *root = fs_info->extent_root; struct btrfs_root *csum_root = fs_info->csum_root; struct btrfs_extent_item *extent; + struct btrfs_bio *bbio = NULL; u64 flags; int ret; int slot; @@ -2914,6 +2920,7 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx, u64 extent_logical; u64 extent_physical; u64 extent_len; + u64 mapped_length; struct btrfs_device *extent_dev; struct scrub_parity *sparity; int nsectors; @@ -3037,10 +3044,21 @@ again: scrub_parity_mark_sectors_data(sparity, extent_logical, extent_len); - scrub_remap_extent(fs_info, extent_logical, - extent_len, &extent_physical, - &extent_dev, - &extent_mirror_num); + mapped_length = extent_len; + ret = btrfs_map_block(fs_info, READ, extent_logical, + &mapped_length, &bbio, 0); + if (!ret) { + if (!bbio || mapped_length < extent_len) + ret = -EIO; + } + if (ret) { + btrfs_put_bbio(bbio); + goto out; + } + extent_physical = bbio->stripes[0].physical; + extent_mirror_num = bbio->mirror_num; + extent_dev = bbio->stripes[0].dev; + btrfs_put_bbio(bbio); ret = btrfs_lookup_csums_range(csum_root, extent_logical, |