From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Mason Subject: Re: btrfs and hotplug, auto-assembly, auto-setup, ... Date: Thu, 11 Dec 2008 08:14:51 -0500 Message-ID: <1229001291.22236.23.camel@think.oraclecorp.com> References: <1228959014.21376.6.camel@think.oraclecorp.com> Mime-Version: 1.0 Content-Type: text/plain Cc: linux-btrfs@vger.kernel.org, Greg To: Kay Sievers Return-path: In-Reply-To: List-ID: On Thu, 2008-12-11 at 03:08 +0100, Kay Sievers wrote: [ ... ] > I have the btrfs detection code in udev since while, to be able to > test it, and I'm tracking the changes. > > After the metadata is finalized, I will come up with a few working > examples how we could make this information easily available, and > possible integrate it into the tools, and we can decide what we think > is the best. > > One thing I like to check now, if I got it correctly - the volume that > gets mounted has: > btrfs_super_block.fsid (the volume, may be used for mount-by-label) > btrfs_super_block.label (the volume, may be used for mount-by-label) Yes > > The devices the volume is assembled from, which can be several, have: > btrfs_super_block.dev_item.uuid (the device uuid, not used in userspace) > btrfs_super_block.dev_item.fsid (the volume uuid, matches > btrfs_super_block.fsid) Yes, that's right. Just to confuse things a little more there's some called a seed filesystem, so FS B can point to FS A and include all of its devices. But, this pointing happens inside the FS device tree and not at the super block level. It just points to the fs uuid, so I think your existing setup will be sufficient. -chris