Re: destroyed disk in btrfs raid

[laie <laie@halifax.rwth-aachen.de>]

On 2014-05-14 23:44, laie wrote:
> On 2014-05-14 20:44, Hugo Mills wrote:
>> On Wed, May 14, 2014 at 08:43:41PM +0200, laie wrote:
>>> On 2014-05-11 16:19, Hugo Mills wrote:
>>> >On Tue, May 13, 2014 at 10:16:59AM +0200, laie wrote:
>>> >>On 2014-05-09 20:01, Hugo Mills wrote:
>>> >>>On Fri, May 09, 2014 at 06:58:27PM +0100, Hugo Mills wrote:
>>> >>>>On Fri, May 09, 2014 at 08:02:45PM +0200, laie wrote:
>>> >>>>> Now I'm looking for a way to tell btrfs to provide me with a list of the
>>> >>>>> corrupted files and delete them afterwards. This would be great, because
>>> >>>>> otherwise it would take very long to get the data back from slow backups.
>>> >>>>
>>> >>>>   Simple solution: cat every file to /dev/null, and see which ones
>>> >>>>fail with an I/O error. With RAID-0 data, losing a device is going to
>>> >>>>damage most files, though, so don't necessarily expect much to survive.
>>> 
>>> I finished building the List, about 40% of the Data is gone. So far 
>>> so good.
>>> 
>>> As next step I planned to delete these files. This is not possible 
>>> because
>>> I'm not able to mount the fs r/w.
>>> 
>>> btrfs: allowing degraded mounts
>>> btrfs: bdev /dev/mapper/luks-0 errs: wr 37519, rd 32783, flush 0, 
>>> corrupt 0,
>>> gen 0
>>> Btrfs: too many missing devices, writeable mount is not allowed
>>> btrfs: open_ctree failed
>>> 
>>> Is it correct remove the missing device now:
>>> 
>>> btrfs device delete missing /mnt
>>> 
>>> Or do I have to add the replacement first?
>> 
>>    You'd have to mount r/w before you can add a new disk. :)
>> 
>>    You should be able to mount r/w using the -o degraded mount option.
> 
> The error above is occurs when I try to mount with
> 
> mount -o degraded source target
> 
> only
> 
> mount -o degraded,ro source target
> 
> works.

I'm still stuck here, does anybody have an idea how its possible to get 
this filesystem to r/w mode?

The only solution I can think of is to copy the undamaged Data to a new 
filesystem. I don't like to do that.