btrfs filesystems can only be mounted after an unclean shutdown if btrfsck is run and immediately killed!

btrfs filesystems can only be mounted after an unclean shutdown if btrfsck is run and immediately killed!

[Konstantinos Skarlatos]

Hi all,
I have two multi-disk btrfs filesystems on a Arch linux 3.4.0 system. 
After a power failure, both filesystems refuse to mount

[   10.402284] Btrfs loaded
[   10.402714] device fsid 1e7c18a4-02d6-44b1-8eaf-c01378009cd3 devid 4 
transid 65282 /dev/sdc
[   10.403108] btrfs: force zlib compression
[   10.403130] btrfs: enabling inode map caching
[   10.403152] btrfs: disk space caching is enabled
[   10.403377] btrfs: failed to read the system array on sdc
[   10.403557] btrfs: open_ctree failed
[   10.431763] device fsid 7f7be913-e359-400f-8bdb-7ef48aad3f03 devid 2 
transid 3916 /dev/sdb
[   10.432180] btrfs: force zlib compression
[   10.433040] btrfs: enabling inode map caching
[   10.433892] btrfs: disk space caching is enabled
[   10.434930] btrfs: failed to read the system array on sdb
[   10.435945] btrfs: open_ctree failed


fstab:

UUID=1e7c18a4-02d6-44b1-8eaf-c01378009cd3 /storage/btrfs btrfs 
noatime,compress-force=zlib,space_cache,inode_cache 0 0
UUID=7f7be913-e359-400f-8bdb-7ef48aad3f03 /storage/btrfs2 btrfs 
noatime,compress-force=zlib,space_cache,inode_cache 0 0


The funny thing is that if i run btrfsck for one second on the first 
filesystem and then kill it with ctrl-c, then both filesystems can be 
mounted without any problems!

I have this problem for many months, probably for all 3.x kernels and 
maybe a bit older, all git btrfs tools since at least late last year.

  [root@linuxserver ~/btrfs-progs]# btrfs fi show /dev/sdb
Label: none  uuid: 7f7be913-e359-400f-8bdb-7ef48aad3f03
         Total devices 2 FS bytes used 1.54TB
         devid    1 size 1.82TB used 1.04TB path /dev/sda
         devid    2 size 1.82TB used 1.04TB path /dev/sdb

Btrfs Btrfs v0.19
  [root@linuxserver ~/btrfs-progs]# btrfs fi show /dev/sdf
Label: none  uuid: 1e7c18a4-02d6-44b1-8eaf-c01378009cd3
         Total devices 4 FS bytes used 4.33TB
         devid    5 size 1.82TB used 1.82TB path /dev/sdg
         devid    4 size 1.82TB used 1.82TB path /dev/sdc
         devid    3 size 1.82TB used 1.79TB path /dev/sdf
         devid    1 size 1.82TB used 1.82TB path /dev/sdd

Btrfs Btrfs v0.19

Re: btrfs filesystems can only be mounted after an unclean shutdown if btrfsck is run and immediately killed!

[Tomasz Torcz]

On Fri, Jun 08, 2012 at 11:26:21AM +0300, Konstantinos Skarlatos wrote:
> Hi all,
> I have two multi-disk btrfs filesystems on a Arch linux 3.4.0
> system. After a power failure, both filesystems refuse to mount

  Multi-device filesystem had to be first fully discovered by
"btrfs device scan".  It is typically done from udev rules. Also,
dracut does it in initramfs for quite a long time.

-- 
Tomasz Torcz                        To co nierealne -- tutaj jest normalne.
xmpp: zdzichubg@chrome.pl          Ziomale na życie mają tu patenty specjalne.

Re: btrfs filesystems can only be mounted after an unclean shutdown if btrfsck is run and immediately killed!

[Konstantinos Skarlatos]

On Παρασκευή, 8 Ιούνιος 2012 11:28:39 πμ, Tomasz Torcz wrote:
> On Fri, Jun 08, 2012 at 11:26:21AM +0300, Konstantinos Skarlatos wrote:
>> Hi all,
>> I have two multi-disk btrfs filesystems on a Arch linux 3.4.0
>> system. After a power failure, both filesystems refuse to mount
>
>    Multi-device filesystem had to be first fully discovered by
> "btrfs device scan".  It is typically done from udev rules. Also,
> dracut does it in initramfs for quite a long time.
>
(Added cc to btrfs list)

You are right, i have forgotten to enable it (arch linux has a new 
rc.conf option for that), i will reboot in a few minutes to test it.
Maybe it would be prudent to give a better error message when such a 
thing happens, or even make mount run btrfs device scan if it detects 
that a multi-drive fs is being mounted?