diff options
| author | Wang Shilong <wangsl.fnst@cn.fujitsu.com> | 2014-06-11 10:55:22 +0800 |
|---|---|---|
| committer | Chris Mason <clm@fb.com> | 2014-06-13 09:52:21 -0700 |
| commit | 5fbc7c59fd22c5a6531b40b0759624b680a95e52 (patch) | |
| tree | dfd0fff7de04cc8250bfd1128bfac9f9ccff3601 | |
| parent | cc68a8a5a4330a4bb72922d0c7a7044ae13ee692 (diff) | |
| download | linux-5fbc7c59fd22c5a6531b40b0759624b680a95e52.tar.bz2 | |
Btrfs: fix unfinished readahead thread for raid5/6 degraded mounting
Steps to reproduce:
# mkfs.btrfs -f /dev/sd[b-f] -m raid5 -d raid5
# mkfs.ext4 /dev/sdc --->corrupt one of btrfs device
# mount /dev/sdb /mnt -o degraded
# btrfs scrub start -BRd /mnt
This is because readahead would skip missing device, this is not true
for RAID5/6, because REQ_GET_READ_MIRRORS return 1 for RAID5/6 block
mapping. If expected data locates in missing device, readahead thread
would not call __readahead_hook() which makes event @rc->elems=0
wait forever.
Fix this problem by checking return value of btrfs_map_block(),we
can only skip missing device safely if there are several mirrors.
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
| -rw-r--r-- | fs/btrfs/reada.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c index 30947f923620..09230cf3a244 100644 --- a/fs/btrfs/reada.c +++ b/fs/btrfs/reada.c @@ -428,8 +428,13 @@ static struct reada_extent *reada_find_extent(struct btrfs_root *root, continue; } if (!dev->bdev) { - /* cannot read ahead on missing device */ - continue; + /* + * cannot read ahead on missing device, but for RAID5/6, + * REQ_GET_READ_MIRRORS return 1. So don't skip missing + * device for such case. + */ + if (nzones > 1) + continue; } if (dev_replace_is_ongoing && dev == fs_info->dev_replace.tgtdev) { |