Re: moving a subvol

[David Sterba <dsterba@suse.cz>]

On Fri, Dec 13, 2013 at 11:31:47AM -0500, Gene Czarcinski wrote:
> On 12/13/2013 11:07 AM, Gene Czarcinski wrote:
> >I have hunted high and low for the information but, if it is out there,
> >it is well hidden.
> >
> >What I want to do:  I want to relocate (move) a subvolume from one BTRFS
> >volume to a different BTRFS volume.
> >
> >I have seen the writeup for incremental backup which takes a snapshot,
> >and then using btrfs-send and btrfs-receive to create a copy on a
> >different volume.  That works fine except the btrfs-receive set the new
> >copy to be readonly.
> >
> >What I want to do is to use that new subvolume read/write.  The only way
> >I have figured out to do this is to create another snapshot on the new
> >volume which is NOT readonly.  I believe that means I need to keep both
> >of these subvolumes around.
> 
> As soon as I sent this I believe I found the answer.
> 
> I was sort of right about creating the new read-write (NOT readonly)
> snapshot.  After it is created simply delete the one which was created by
> btrfs-receive.

ATM, this is the way to do it. There's an ioctl to toggle the RO/RW
status of a subvolume, so it could save you one snapshot, but there's
not tool support to do that. I hope this will be possible with the
upcomming 'per-object properties' feature.

david