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From: Ed Tomlinson <tomlins@cam.org>
Date: Mon, 30 Apr 2001 00:23:14 -0400
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Subject: [linux-lvm] Re: [reiserfs-list] mounting reiserfs snapshot fails
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To: Chris Mason <mason@suse.com>, reiserfs-list@namesys.com
Cc: linux-lvm@sistina.com

On Sunday 29 April 2001 21:48, Chris Mason wrote:
> On Friday, April 13, 2001 01:29:58 PM -0400 Ed Tomlinson <tomlins@cam.org>
>
> wrote:
> > Hi,
> >
> > Using debian sid, 2.4.3-ac5, lvm 0.91 beta7, with the vfs locking
> > patch applied I get:
> >
> > oscar# mount /dev/lv/snap /snap -t reiserfs -oro
> > mount: wrong fs type, bad option, bad superblock on /dev/lv/snap,
> >        or too many mounted file systems
> >
> > When trying to mount the snap shot.  It was created with:
> > lvcreate -L 1G -s -n snap /dev/lv/root /dev/hdg1
> > without problems
>
> I'm not sure what you're doing that I wasn't, but I've tried a bunch of
> times to reproduce this over the last few weeks.  Tonight I finally did ;-)
>
> The bug is that reiserfs needs to try harder to wait for the current
> transaction to end.  A slight change in the semantics there didn't get
> carried into the reiserfs write_super_lockfs call (reiserfs_block_writes
> used to be enough on its own).
>
> But, it only hits when LVM can create the snapshot faster than the next
> reiserfs writer can commit the transaction, which doesn't happen often for
> me.
>
> Anyway, here's a patch (VFS locking patch for 2.4.4 will follow in a sec).

Chris,

This is not fixing the problem here.  What else do you need to figure this
one out?  I did verify that I built from souce with both the fix VFS locking
the the reiserfs fix applied.  Symptoms remain the same, debugreiserfs is 
still finding a null block where it expects the sb.

Ed