Re: Howto mount intact left-over device of a degraded btrfs-raid?

[Josef Bacik <josef@redhat.com>]

On Tue, Jan 26, 2010 at 01:20:30PM +0100, Mr. Tux wrote:
> On Monday 25 January 2010 23:08:39 Josef Bacik wrote:
> 
> Hi Josef
> 
> >
> > Hmm well I'm trying to reproduce that here and it's working fine, course I
> > can't pull a cable on my disk since I only have one disk to test with. 
> > Would you mind sending me your dmesg after you try
> >
> > mount -o degraded /dev/sda1 /mnt/
> >
> > so I can see whats going on.  Thanks,
> >
> 
> Did you try 2.6.32.2 from kernel.org? Is it possible to use  a second test 
> drive like I did? I know you can create a raid array with one device missing, 
> but the segfault happened with a two member raid1.
> 
> I don't have the test environment any more, so I can't offer a backtrace right 
> now - but I will set it up again in the next few days. If it happens again I 
> will contact you and send you a backtrace.
>

Ok I think I've tracked down all the various problems that you were having with
this.  I've sent 3 patches to the list just now

Btrfs: check total number of devices when removing missing
Btrfs: check return value of open_bdev_exclusive properly
Btrfs: do not mark the chunk as readonly if in degraded mode

Make sure you run btrfsctl -a before running mount -o degraded.  I made that
mistake and things still didnt work.  Let me know if you have any problems.
Thanks,

Josef