Say there is a raid1 btrfs which consists of two disks, after one disk becomes unavailable, we can still mount it in degraded mode once, for the second mount it would refuse to mount it with an error "BTRFS warning (device sdf): missing devices (1) exceeds the limit (0), writeable mount is not allowed" The reason is that during the first mount (with the default mount option), it creates a chunk of single profile so that another mount will report the limit to tolerate missing or faulty devices as 0. But we're mounting the filesystem from the device where the single profile chunk lives, we can safely allow it to be mounted in the degraded mode. Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx> --- fs/btrfs/disk-io.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index eb1ee7b..b65a265 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3686,8 +3686,15 @@ int btrfs_calc_num_tolerated_disk_barrier_failures( &space); if (space.total_bytes == 0 || space.used_bytes == 0) continue; - flags = space.flags; + /* + * skip single profile as we have opened this + * device for single profile + */ + if ((space.flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0) + continue; + + flags = space.flags; num_tolerated_disk_barrier_failures = min( num_tolerated_disk_barrier_failures, btrfs_get_num_tolerated_disk_barrier_failures( -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
