[linux-lvm] snapshots and reiserfs

[Greg Freemyer]

On Thu, 2004-04-08 at 14:18, Mark M. Hoffman wrote:
> Hello:
> 
> Sometimes, but not always, I am unable to mount a snapshot.
> When it fails, I see the following lines in my logs...
> 
> kernel: reiserfs: checking transaction log (device 3a:06) ...
> kernel: clm-2076: device is readonly, unable to replay log
> kernel: Replay Failure, unable to mount
> kernel: reiserfs_read_super: unable to initialize journal space
> 
> I am using RedHat 9 with the following stock packages:
> 
> kernel-smp-2.4.20-30.9
> lvm-1.0.3-12
> reiserfs-utils-3.6.4-5
> 
> I have not tried the combination of snapshots & reiserfs with
> earlier RedHat packages so I don't know if this is a regression.
> 
> After some STFW, I thought I might need a "VFS lock" patch.
> However, it looks like this was already included by RedHat...
> in kernel-smp-2.4.20-30.9.src.rpm there is already this patch:
> linux-2.4.18-lvm-VFSlock.patch.
> 
> Is there anything else I can try or look at?
> 
> Also, is it necessary that the filesystem be quiescent in order to
> create a snapshot?  I could temporarily remount readonly to create
> the snapshot, but I would like not to have to do that.
> 
> Thanks and regards,

XFS used to have this problem about a year ago.

For xfs the issue was that xfs mount attempted a journal replay even
when the mount was read-only.  XFS now skips journal replay on read-only
mounts.

You should ask on a reiserfs list if they skip journal replay on
read-only mounts or not.

Greg
-- 
Greg Freemyer