On Fri, Feb 14, 2003 at 04:48:01PM +0100, Christian Limpach wrote:
> I'm looking for advice on how to bring a mounted filesystem to an almost 
> clean state.  I have a device driver which lets me take a snapshot at the 
> blockdevice level and doing this to a mounted filesystem I get a snapshot 
> which is in a more or less clean state.

Even without addressing the filesystem issues at the layer above,
I'd be interested in such a device.  Is this something you'll be
able to release when you're done?

At the upper layer, it's probably something that will need direct
support from the filesystems. In the softdep case, something that
can be inserted in the dependency chain as a barrier - and when it
finally hits the lower layer device in order, it triggers the actual
snapshot to happen. That should avoid the need for locking, which
you need to avoid so your snapshots remain transparent.

--
Dan.