From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josef Bacik Subject: Re: What to do about subvolumes? Date: Wed, 1 Dec 2010 15:09:52 -0500 Message-ID: <20101201200949.GG7021@localhost.localdomain> References: <20101201142136.GD427@dhcp231-156.rdu.redhat.com> <20101201194404.GE17142@fieldses.org> <20101201195433.GE7021@localhost.localdomain> <20101201200007.GH17142@fieldses.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Josef Bacik , linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, chris.mason@oracle.com, hch@lst.de, ssorce@redhat.com To: "J. Bruce Fields" Return-path: Content-Disposition: inline In-Reply-To: <20101201200007.GH17142@fieldses.org> Sender: linux-btrfs-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Wed, Dec 01, 2010 at 03:00:08PM -0500, J. Bruce Fields wrote: > On Wed, Dec 01, 2010 at 02:54:33PM -0500, Josef Bacik wrote: > > Oh well crud, I was hoping that I could leave the inode numbers as 256 for > > everything, but I forgot about readdir. So the inode item in the parent would > > have to have a unique inode number that would get spit out in readdir, but then > > if we stat'ed the directory we'd get 256 for the inode number. Oh well, > > incompat flag it is then. > > I think you're already fine: > > # mkdir TMP > # dd if=/dev/zero of=TMP-image bs=1M count=512 > # mkfs.btrfs TMP-image > # mount -oloop TMP-image TMP/ > # btrfs subvolume create sub-a > # btrfs subvolume create sub-b > ../readdir-inos . > . 256 256 > .. 256 4130609 > sub-a 256 256 > sub-b 257 256 > > Where readdir-inos is my silly test program below, and the first number is from > readdir, the second from stat. > Heh as soon as I typed my email I went and actually looked at the code, looks like for readdir we fill in the root id, which will be unique, so hotdamn we are good and I don't have to use a stupid incompat flag. Thanks for checking that :), Josef