Hey, all. I did a "convert" on my ext-3 system, and now I''ve got a monolithic btrfs volume. I''d like to break / and /home into subvolumes. /home is easy (I think): I just create a subvolume, and move stuff into it, and mount it. Done. But how do I do that for root? (Don''t worry about the actual mounting, grub, etc.,; I have a different system that works the way I want it to.) Thanks, -Ken -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Nov 10, 2011 at 09:50:00AM -0500, Ken D''Ambrosio wrote:> Hey, all. I did a "convert" on my ext-3 system, and now I''ve got a monolithic > btrfs volume. I''d like to break / and /home into subvolumes. /home is easy (I > think): I just create a subvolume, and move stuff into it, and mount it. Done. > But how do I do that for root? (Don''t worry about the actual mounting, grub, > etc.,; I have a different system that works the way I want it to.)The top level of the filesystem is itself a subvolume, so you could just leave it like that. Alternatively, if you want the top level to be simply a container for subvolumes (and to use a default subvolume to mount / ), then you could do the switch-over by making a snapshot of your current /, remounting with the snapshot as / (possibly using "btrfs sub set-default"), and then mounting subvolid=0 on /media/btrfs-management to delete the old contents of / (I hope that made sense) 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 --- "He''s a nutcase, you know. There''s no getting away from it -- --- he''ll end up with a knighthood"
On Thu, 10 Nov 2011 14:59:44 +0000 Hugo Mills <hugo@carfax.org.uk> wrote> Alternatively, if you want the top level to be simply a container > for subvolumes (and to use a default subvolume to mount / ), then you > could do the switch-over by making a snapshot of your current /, > remounting with the snapshot as / (possibly using "btrfs sub > set-default"), and then mounting subvolid=0 on /media/btrfs-management > to delete the old contents of /So, I did this. I think correctly: mkdir /tmp/foo mount /dev/sda1 /tmp/foo -o subvolid=0 And lo! I did an ls, and everything was there. And then the kernel panic''d. I rebooted, re-mounted, and it was there again. And then the kernel panic''d. Last time, I didn''t even try an ls -- I just did a "btrfs subvol list /tmp/foo", and yet another panic. This is running 3.2rc1 (with tools built off the git repository on kernel.org, if that makes any difference). My system is, technically, working. Any suggestions on how to get rid of my old root? Thanks... -Ken -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Nov 11, 2011 at 02:06:42PM -0500, Ken D''Ambrosio wrote:> On Thu, 10 Nov 2011 14:59:44 +0000 Hugo Mills <hugo@carfax.org.uk> wrote > > > Alternatively, if you want the top level to be simply a container > > for subvolumes (and to use a default subvolume to mount / ), then you > > could do the switch-over by making a snapshot of your current /, > > remounting with the snapshot as / (possibly using "btrfs sub > > set-default"), and then mounting subvolid=0 on /media/btrfs-management > > to delete the old contents of / > > So, I did this. I think correctly: > mkdir /tmp/foo > mount /dev/sda1 /tmp/foo -o subvolid=0 > And lo! I did an ls, and everything was there. And then the kernel panic''d. > I rebooted, re-mounted, and it was there again. And then the kernel panic''d.I''m starting to see a pattern forming here. ;)> Last time, I didn''t even try an ls -- I just did a "btrfs subvol list > /tmp/foo", and yet another panic. This is running 3.2rc1 (with tools built off > the git repository on kernel.org, if that makes any difference).The tools shouldn''t make a difference to this. (Anything that makes the kernel panic is a bug in the kernel, not in the thing that triggers it).> My system is, technically, working. Any suggestions on how to get rid of my > old root?I''d suggest reporting (on this mailing list) the panic message(s) you got, and how you got to them. I know there''s been quite a few additional patches worked on since Chris pushed out the stack for -rc1, so it''s quite plausible that your particular problem has already been fixed in someone''s tree. The other thing you could try is dropping back to 3.1 and see if that''s stable for you with this. 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 --- Quidquid latine dictum sit, altum videtur. ---
On Fri, 11 Nov 2011 19:13:09 +0000 Hugo Mills <hugo@carfax.org.uk> wrote> I''d suggest reporting (on this mailing list) the panic message(s) > you got, and how you got to them. I know there''s been quite a few > additional patches worked on since Chris pushed out the stack for > -rc1, so it''s quite plausible that your particular problem has already > been fixed in someone''s tree.Hmmm. I just pulled Chris''s tree, and it seems to have done the trick. It''s mounting, now. I''m being leery of outright deleting, because grub-mkconfig seems confused about being mounted off a different subvolume: grub-probe: error: cannot find a device for / (is /dev/mounted?). (Needless to say, /dev/ *is* mounted. Likely, I''ve somehow confused it with fstab or something.) But I''m able to look at directories, cat/cp files, etc., so I now at least *could* blow things away. Which is handy. Thanks! -Ken -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Nov 11, 2011 at 04:47:17PM -0500, Ken D''Ambrosio wrote:> On Fri, 11 Nov 2011 19:13:09 +0000 Hugo Mills <hugo@carfax.org.uk> wrote > > > I''d suggest reporting (on this mailing list) the panic message(s) > > you got, and how you got to them. I know there''s been quite a few > > additional patches worked on since Chris pushed out the stack for > > -rc1, so it''s quite plausible that your particular problem has already > > been fixed in someone''s tree. > > Hmmm. I just pulled Chris''s tree, and it seems to have done the trick. It''s > mounting, now. I''m being leery of outright deleting, because grub-mkconfig > seems confused about being mounted off a different subvolume: > grub-probe: error: cannot find a device for / (is /dev/mounted?). > > (Needless to say, /dev/ *is* mounted. Likely, I''ve somehow confused it with > fstab or something.)I think grub has some problems with some of the btrfs features. I don''t know if we''ve got a decent list of issues written down yet.> But I''m able to look at directories, cat/cp files, etc., so I now at least > *could* blow things away. Which is handy.Glad the upgrade''s helped. Just make sure you''ve got off-machine backups, and the will to use them, and you''ll be fine. :) 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 --- I always felt that as a C programmer, I --- was becoming typecast.