From: Adam Borowski Date: Tue, 28 Mar 2017 16:55:05 +0200 Subject: btrfs: warn about RAID5/6 being experimental at mount time Bug-Debian: https://bugs.debian.org/863290 Origin: https://bugs.debian.org/863290#5 Too many people come complaining about losing their data -- and indeed, there's no warning outside a wiki and the mailing list tribal knowledge. Message severity chosen for consistency with XFS -- "alert" makes dmesg produce nice red background which should get the point across. Signed-off-by: Adam Borowski [bwh: Also add_taint() so this is flagged in bug reports] --- fs/btrfs/disk-io.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3060,6 +3060,15 @@ retry_root_backup: btrfs_set_and_info(fs_info, SSD, "enabling ssd optimizations"); } + if ((fs_info->avail_data_alloc_bits | + fs_info->avail_metadata_alloc_bits | + fs_info->avail_system_alloc_bits) & + BTRFS_BLOCK_GROUP_RAID56_MASK) { + btrfs_alert(fs_info, + "btrfs RAID5/6 is EXPERIMENTAL and has known data-loss bugs"); + add_taint(TAINT_AUX, LOCKDEP_STILL_OK); + } + /* * Mount does not set all options immediately, we can do it now and do * not have to wait for transaction commit