Am Tue, 5 Apr 2016 17:52:40 +0900 schrieb Tsutomu Itoh <t-itoh@xxxxxxxxxxxxxx>: > On 2016/04/05 16:56, Anand Jain wrote: > > On 04/05/2016 08:08 AM, Tsutomu Itoh wrote: > >> When fs_devices->latest_bdev is deleted or is replaced, sb->s_id > >> has not been updated. > >> As a result, the deleted device name is displayed by btrfs_printk. > >> > >> [before fix] > >> # btrfs dev del /dev/sdc4 /mnt2 > >> # btrfs dev add /dev/sdb6 /mnt2 > >> > >> [ 217.458249] BTRFS info (device sdc4): found 1 extents > >> [ 217.695798] BTRFS info (device sdc4): disk deleted /dev/sdc4 > >> [ 217.941284] BTRFS info (device sdc4): disk added /dev/sdb6 > >> > >> [after fix] > >> # btrfs dev del /dev/sdc4 /mnt2 > >> # btrfs dev add /dev/sdb6 /mnt2 > >> > >> [ 83.835072] BTRFS info (device sdc4): found 1 extents > >> [ 84.080617] BTRFS info (device sdc3): disk deleted /dev/sdc4 > >> [ 84.401951] BTRFS info (device sdc3): disk added /dev/sdb6 > > > > > > [PATCH 05/13] Btrfs: fix fs logging for multi device > > > > any comments ? > > > > We would want to maintain the logging prefix as constant, so that > > troubleshooters with filters/scripts will find it helpful. > > I think it is good to make the identifier constant for the > troubleshooting. However, fsid(uuid) is a little long for the print > purpose, I think. (But an appropriate value isn't found...) How about setting this to a CRC16 of the fsid(uuid)? Or a value which is increased at every new mount, then logging which devices belong to this value if the devices change? Like: BTRFS info: pool id 1 has (/dev/sdc4, /dev/sdb6) BTRFS info (pool 1): found 1 extents ... I think the way btrfs magically assigns any member device to the pool somehow feels uncomfortable anyways. Btrfs better should expose the compound devices as single device nodes like maybe /dev/btrfs/pool0 etc. Every time I boot my multi-device btrfs, according to mount, the associated device changes (sometimes mount says /dev/sda1 is mounted, the next time it's /dev/sdb1). This is not deterministic - and that is almost always bad some way or another. -- Regards, Kai Replies to list-only preferred. -- 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
