[linux-lvm] lvm2 snapshot BREAKS on 2nd snapshot

[James G. Sack (jim)]

>..(from digest)..
> Message: 2
> Date: Wed, 2 Nov 2005 00:03:53 +0000
> From: Alasdair G Kergon <agk at redhat.com>
> Subject: Re: [linux-lvm] lvm2 snapshot BREAKS on 2nd snapshot
> To: linux-lvm at redhat.com
> Message-ID: <20051102000353.GH26394 at agk.surrey.redhat.com>
> Content-Type: text/plain; charset=us-ascii
> 
> On Tue, Nov 01, 2005 at 08:03:21AM -0800, James G. Sack (jim) wrote:
> > I get this kcopyd BUG (and consequent Oops)
> 
> Here's a related patch to try from Jan Blunck.
>   [The fix still needs moving into bio_list_merge() not its caller.]
> 
> If things keep to schedule, there'll be new userspace activation
> code around the end of this week aimed at avoiding
> snapshot failures locking up machines, and I'll be back dealing
> with the outstanding kernel patches (including this one) by the 
> middle of next week.
> 
> Alasdair

I tried the patch on the latest FC4 kernel (2.6.13-1.1532_FC4), and it
still triggers the kcopyd.c BUG at line 145.

The behavior I get, may actually be a consequence of (or worsened by) a
simultaneous loop running dmsetup info -- so maybe there's some other
lock error involved, too?

Anyway, I look forward to the upcoming improvements -- thanks, agk.

For now, I am living with the constraint that lvm2 snapshots work ok as
long as there is not more than one snapshot on any given origin volume.


..jim