On Tuesday, February 26, 2002 09:59:19 AM -0700 Andreas Dilger <adilger@turbolabs.com> wrote: > On Feb 26, 2002 14:54 +0100, Urs Thuermann wrote: >> I tried creating a snapshot of a ext2 file system on a LV. I expected >> a fsck on the snapshot device to give no errors, i.e. a consistent >> file system. This is ok, as long as there is no (or little) load on >> the file system when creating the snapshot. > > Yes. > >> However, on a busy file system, the created snapshot has lots of >> errors found by fsck. >> >> Is it this what the VFS lock patch is for? If so, why hasn't it been >> integrated into the standard kernel? Has it flaws in it? Maybe >> performance wise? > > The VFS lock patch only applies to journaled filesystems. There has not > been any attempt to include support for sync_super_lockfs for ext2. I > _think_ that if you tried to mount the ext2 snapshot, it will still > work, even though it is inconsistent. Obviously it would be better to > fix it so that ext2 snapshots are always consistent. Yes, its very easy for the journaled filesystems (except XFS ;-) to do the snapshot locking, since snapshot locking is really just grab a lock on the log, finish transactions, let LVM do its thing, then release the lock. For ext2, the best we could do would probably be a hack based on locking the super. As far as I know, nobody is planning on this, especially given how easy it is to go from ext2->ext3. -chris _______________________________________________ linux-lvm mailing list linux-lvm@sistina.com http://lists.sistina.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html
