On Fri, Oct 16, 2009 at 01:42:49PM +0200, Sander Smeenk wrote: > Recently i switched on 'snapdir=visible' on one of the zfs volumes to > easily expose the available snapshots and then i noticed rsync -removes- > snapshots even though i am not able to do so myself, even as root, with > plain /bin/rm.
I never liked this interface. I want snapshots to be immutable to operations within the filesystem itself. > What's the deal here. :) > > I was under the impression that rsync uses unlink() like 'rm' does? > How come rsync -can- remove the snapshot directory when exposed with > 'snapdir=visible' and i can't do it with /bin/rm? I think you mean 'rmdir' rather than unlink. My assumption is that 'rm' is being smart and won't attempt to remove a directory that it thinks has data (which would normally fail). In looking at a 'truss' of /bin/rm <snap>, it never issued an unlink or rmdir, just complained that the directory wasn't empty. /bin/rmdir on the other hand did do a rmdir(2), and that does destroy the snapshot. Although I see sometimes the rmdir fails. If I've been doing "something" in a snapshot (sometimes some stats are enough), then it seems to "lock" the snapshot and the rmdir fails (with EBUSY). -- Darren _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
