From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hugo Mills Subject: Re: How to get the default subvolume? Date: Fri, 8 Jul 2011 12:01:42 +0100 Message-ID: <20110708110142.GC19280@carfax.org.uk> References: <20110708095802.GA11513@yangyi-dev.bj.intel.com> <20110708095802.GA19280@carfax.org.uk> <20110708101329.GB19280@carfax.org.uk> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="QRj9sO5tAVLaXnSD" Cc: "linux-btrfs@vger.kernel.org" To: "Yang, Yi Y" Return-path: In-Reply-To: List-ID: --QRj9sO5tAVLaXnSD Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Jul 08, 2011 at 06:28:54PM +0800, Yang, Yi Y wrote: > From your source, you defined some structures using python and use > them to get and parse btrfs metadata, very advanced and complicated > :-), do you know there is any library to provide similar APIs in > order that I can use some advanced APIs and don't need to worry > about frequent changes of btrfs superblock and other metadata. The fundamental btrfs data structures (which you'll find defined in ctree.h in the btrfs-progs source, and which are mirrored in my python code) won't change much, since they define the on-disk layout. Changing those structures creates incompatible filesystems, which is a Bad Thing, so it doesn't happen all that often. Hugo. PS. On most development mailing lists, it's conventional to write your replies below the text you're replying to, not above. > -----Original Message----- > From: linux-btrfs-owner@vger.kernel.org [mailto:linux-btrfs-owner@vger.kernel.org] On Behalf Of Hugo Mills > Sent: Friday, July 08, 2011 6:13 PM > To: Yang, Yi Y > Cc: linux-btrfs@vger.kernel.org > Subject: Re: How to get the default subvolume? > > On Fri, Jul 08, 2011 at 06:06:02PM +0800, Yang, Yi Y wrote: > > That's great, can you share your source code with me? I'm very eager > > to get this now :-) > > http://carfax.org.uk/btrfs-gui > http://git.darksatanic.net/repo/btrfs-gui.git/ > > You probably want the btrfsgui.hlp.subvol.sv_list() function. > > Hugo. > > > -----Original Message----- > > From: Hugo Mills [mailto:hugo@carfax.org.uk] > > Sent: Friday, July 08, 2011 5:58 PM > > To: Yang, Yi Y > > Cc: linux-btrfs@vger.kernel.org > > Subject: Re: How to get the default subvolume? > > > > On Fri, Jul 08, 2011 at 05:58:02PM +0800, Yi Yang wrote: > > > I know I can set the default subvolume for a btrfs fs using > > > > > > sudo btrfs subvolume set-default 256 /btrfs/mnt > > > > > > But after that, how can get the default subvolume name? In my > > > opinion, btrfs-progs should provide "btrfs subvolume get-default > > > /btrfs/mnm" to get the default subvolume id and name, I think it is > > > very easy to do this in btrfs-progs and btrfs kernel space. > > > > I don't think the current btrfs-progs will do it. As you pointed > > out though, it's pretty easy to write the code to get the information > > (I implemented it for btrfs-gui without any additional kernel code, > > for example). We just need someone to implement it. :) > > > > I'd do it myself, but there's about a dozen things higher up my priority list right now. > > > > Hugo. > > > -- === Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk === PGP key: 515C238D from wwwkeys.eu.pgp.net or http://www.carfax.org.uk --- vi: The core of evil. --- --QRj9sO5tAVLaXnSD Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iD8DBQFOFuOWIKyzvlFcI40RAstIAKCi0g88Q33asPPY3uXAMGUspRhkcgCbBymD s3iJAY2iV2EcaDBKvLtoGaU= =dLmS -----END PGP SIGNATURE----- --QRj9sO5tAVLaXnSD--