Subject: Re: how to bring a mounted filesystem to an almost clean state?
To: Stephan Uphoff <firstname.lastname@example.org>
From: Christian Limpach <email@example.com>
Date: 02/15/2003 01:50:21
Quoting Stephan Uphoff <firstname.lastname@example.org>:
> Christian Limpach wrote:
> > I'm going to try to vn_lock all the vnodes on the filesystem
> > and then sync.
> How would you obey the locking order to avoid deadlocks ?
do you mean that the sync will also need to lock those vnodes? Maybe I could
have the sync routine keep the locks it acquires? I haven't really thought
this through and I'm not too familiar with these issues (yet). What I want
to do (block all modifying access to the filesystem) seems to be achieved by
blocking vn_write's on the filesystem and at a first glance locking the vnode
seemed to accomplish this.
Also I'm mostly only looking for a best effort solution, I don't really use
snapshots much, I implemented the snapshot functionality to test the limits
of my generic blockdevice mapping framework/driver/ccd-on-steroids-thingy ;-)
Christian Limpach <email@example.com>