From 4330e183c9537df20952d4a9ee142c536fb8ae54 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Thu, 9 Mar 2017 09:34:37 +0800 Subject: [PATCH] btrfs: Do chunk level check for degraded rw mount Now use the btrfs_check_rw_degradable() to check if we can mount in the degraded mode. With this patch, we can mount in the following case: # mkfs.btrfs -f -m raid1 -d single /dev/sdb /dev/sdc # wipefs -a /dev/sdc # mount /dev/sdb /mnt/btrfs -o degraded As the single data chunk is only on sdb, so it's OK to mount as degraded, as missing one device is OK for RAID1. But still fail in the following case as expected: # mkfs.btrfs -f -m raid1 -d single /dev/sdb /dev/sdc # wipefs -a /dev/sdb # mount /dev/sdc /mnt/btrfs -o degraded As the data chunk is only in sdb, so it's not OK to mount it as degraded. Reported-by: Zhao Lei Reported-by: Anand Jain Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/disk-io.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 080e2eb..78fc7f5 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3035,15 +3035,10 @@ retry_root_backup: btrfs_err(fs_info, "failed to read block groups: %d", ret); goto fail_sysfs; } - fs_info->num_tolerated_disk_barrier_failures = - btrfs_calc_num_tolerated_disk_barrier_failures(fs_info); - if (fs_info->fs_devices->missing_devices > - fs_info->num_tolerated_disk_barrier_failures && - !(sb->s_flags & MS_RDONLY)) { + + if (!(sb->s_flags & MS_RDONLY) && !btrfs_check_rw_degradable(fs_info)) { btrfs_warn(fs_info, -"missing devices (%llu) exceeds the limit (%d), writeable mount is not allowed", - fs_info->fs_devices->missing_devices, - fs_info->num_tolerated_disk_barrier_failures); + "writeable mount is not allowed due to too many missing devices"); goto fail_sysfs; } -- 2.7.4