From: Kai Krakow <hurikhan77@gmail.com>
To: linux-btrfs@vger.kernel.org
Subject: Re: [PATCH] Btrfs: fix missing s_id setting
Date: Wed, 6 Apr 2016 09:26:35 +0200 [thread overview]
Message-ID: <20160406092635.05f6c857@jupiter.sol.kaishome.de> (raw)
In-Reply-To: 57037CD8.2020804@jp.fujitsu.com
Am Tue, 5 Apr 2016 17:52:40 +0900
schrieb Tsutomu Itoh <t-itoh@jp.fujitsu.com>:
> 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.
prev parent reply other threads:[~2016-04-06 7:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-05 0:08 [PATCH] Btrfs: fix missing s_id setting Tsutomu Itoh
2016-04-05 7:56 ` Anand Jain
2016-04-05 8:52 ` Tsutomu Itoh
2016-04-05 23:56 ` Tsutomu Itoh
2016-04-06 7:26 ` Kai Krakow [this message]
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