Old (almost 2 years) btrfs failed fs. Parent transid failure. Can it be fixed ?

Old (almost 2 years) btrfs failed fs. Parent transid failure. Can it be fixed ?

[Tommy Jonsson]

Hi, i have an old btrfs file-system that crashed on a power-failure
for about 2 years ago.
I talked a bit with Chris Mason at the time and a btrfsck was about to
be released. It never was :-]
But now 2 years later i thought i would give it a try again.
And before you point it out, yes i should have had backup and such but
i didn't as it isn't terrible important data.

Its a 3 disk fs spanning over /dev/sda, sdc, sdd. About 3TB.
I believe it was created like this (default options):
mkfs.btrfs /dev/sda
btrfs device add /dev/sda /dev/sdc
btrfs device add /dev/sda /dev/sdd

i have clone the
git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-progs.git
(at 2012-10-29) and compiled the tools.

sudo mount -t btrfs /dev/sda /mnt/disk/
>mount: wrong fs type, bad option, bad superblock on /dev/sda,
>missing codepage or helper program, or other error
>In some cases useful info is found in syslog - try
>dmesg | tail  or so

dmesg
>[2579559.000820] device fsid 7278c712-5d48-4a73-b40d-6708a45a0b9b devid 3 transid 39651 /dev/sda
>[2579559.035116] parent transid verify failed on 2721514774528 wanted 39651 found 39649
>[2579559.035130] btrfs: failed to read tree root on sda
>[2579559.036887] btrfs: open_ctree failed

/var/syslog
>kernel: [2578915.306144] device fsid 7278c712-5d48-4a73-b40d-6708a45a0b9b devid 3 transid 39651 /dev/sda
>kernel: [2578915.368611] device fsid 7278c712-5d48-4a73-b40d-6708a45a0b9b devid 1 transid 39651 /dev/sdc
>kernel: [2578915.416839] device fsid 7278c712-5d48-4a73-b40d-6708a45a0b9b devid 2 transid 39650 /dev/sdd

sudo ./btrfs-debug-tree /dev/sda
>parent transid verify failed on 2721514774528 wanted 39651 found 39649
>parent transid verify failed on 2721514774528 wanted 39651 found 39649
>Ignoring transid failure
>btrfs-debug-tree: root-tree.c:46: btrfs_find_last_root: Assertion `!(path->slots[0] == 0)' failed.

sudo ./btrfsck /dev/sda
>parent transid verify failed on 2721514774528 wanted 39651 found 39649
>parent transid verify failed on 2721514774528 wanted 39651 found 39649
>Ignoring transid failure
>btrfsck: root-tree.c:46: btrfs_find_last_root: Assertion `!(path->slots[0] == 0)' failed.

sudo ./btrfs-find-root /dev/sda
>Super think's the tree root is at 2721514774528, chunk root 20971520
>Well block 39415808 seems great, but generation doesn't match, have=39, want=39651
>Well block 42041344 seems great, but generation doesn't match, have=40, want=39651
>Well block 44482560 seems great, but generation doesn't match, have=41, want=39651
>Well block 46776320 seems great, but generation doesn't match, have=42, want=39651
>Well block 49131520 seems great, but generation doesn't match, have=43, want=39651
>Well block 51474432 seems great, but generation doesn't match, have=44, want=39651
>Well block 54140928 seems great, but generation doesn't match, have=45, want=39651
>... snip lots of lines ....
>Well block 2721697734656 seems great, but generation doesn't match, have=36242, want=39651
>Well block 2721698918400 seems great, but generation doesn't match, have=36243, want=39651
>Well block 2721699729408 seems great, but generation doesn't match, have=36244, want=39651
>Well block 2721700720640 seems great, but generation doesn't match, have=36245, want=39651
>Well block 2721701867520 seems great, but generation doesn't match, have=36246, want=39651
>Well block 2721703084032 seems great, but generation doesn't match, have=36247, want=39651
>Well block 2721704181760 seems great, but generation doesn't match, have=36248, want=39651
>No more metdata to scan, exiting

Anyone got any tips or is it time for a format and new start ?
Many thanks!
// Tommy Jonsson

Re: Old (almost 2 years) btrfs failed fs. Parent transid failure. Can it be fixed ?

[Tomasz Torcz]

On Mon, Oct 29, 2012 at 01:22:59PM +0100, Tommy Jonsson wrote:
> Hi, i have an old btrfs file-system that crashed on a power-failure
> for about 2 years ago.
> 
> i have clone the
> git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-progs.git
> (at 2012-10-29) and compiled the tools.

  I think you need to get branch "dangerdonoteveruse" to get real fsck code.
 
> sudo mount -t btrfs /dev/sda /mnt/disk/

 Could you try with "-o recovery"?

-- 
Tomasz Torcz                                                       72->|   80->|
xmpp: zdzichubg@chrome.pl                                          72->|   80->|

Re: Old (almost 2 years) btrfs failed fs. Parent transid failure. Can it be fixed ?

[Hugo Mills]

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On Mon, Oct 29, 2012 at 01:33:13PM +0100, Tomasz Torcz wrote:
> On Mon, Oct 29, 2012 at 01:22:59PM +0100, Tommy Jonsson wrote:
> > Hi, i have an old btrfs file-system that crashed on a power-failure
> > for about 2 years ago.
> > 
> > i have clone the
> > git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-progs.git
> > (at 2012-10-29) and compiled the tools.
> 
>   I think you need to get branch "dangerdonoteveruse" to get real fsck code.

   That's a very outdated piece of advice. That code is now in
mainline btrfs-progs, and has been since March. Tommy has the correct
and up-to-date version of the progs.

> > sudo mount -t btrfs /dev/sda /mnt/disk/
> 
>  Could you try with "-o recovery"?

   That's worth a try as a first step.

   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
   --- The last man on Earth sat in a room.  Suddenly, there was a ---   
                           knock at the door.                            

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Re: Old (almost 2 years) btrfs failed fs. Parent transid failure. Can it be fixed ?

[Tommy Jonsson]

Tomasz Torcz <tomek <at> pipebreaker.pl> writes:

>   I think you need to get branch "dangerdonoteveruse" to get real fsck code.
> 
> > sudo mount -t btrfs /dev/sda /mnt/disk/
> 
>  Could you try with "-o recovery"?
> 

As hugo said i think i got the correct source.

Anyway mount with recovery does not work.

sudo mount -t btrfs -o recovery /dev/sda /mnt/superdisk/
>mount: wrong fs type, bad option, bad superblock on /dev/sda,
>missing codepage or helper program, or other error
>In some cases useful info is found in syslog - try
>dmesg | tail  or so

dmesg
>[2582520.375909] device fsid 7278c712-5d48-4a73-b40d-6708a45a0b9b devid 3 
>transid 39651 /dev/sda
>[2582520.377733] btrfs: enabling auto recoveryparent transid verify failed 
>on 2721514774528 wanted 39651 found 39649
>[2582520.394180] btrfs: failed to read tree root on sda
>[2582520.395848] btrfs: open_ctree failed

Thanks for your intrest!