Subject: how to bring a mounted filesystem to an almost clean state?
To: None <tech-kern@NetBSD.ORG>
From: Christian Limpach <email@example.com>
Date: 02/14/2003 16:48:01
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.
I've tried VFS_SYNC with ~MNT_ASYNC, like in sys_sync. This helps somewhat
but there's inconsistencies when there's activity on the filesystem, a few on
plain ffs filesystems and a lot on softdep ffs filesystems. It seems to me
like I'd need some way to block vn_write's on the filesystem until I have
sync'ed the filesystem and taken the snapshot. There doesn't seem to be a
per filesystem lock to block all (write-)io, maybe there should be? I'm
going to try to vn_lock all the vnodes on the filesystem and then sync. Is
this the best solution or are there other options?
Christian Limpach <firstname.lastname@example.org>