Re: Inconsistent reports after disk-error.

Chris Mason
2010-01-20T21:35:55Z

On Mon, Jan 18, 2010 at 11:45:40PM +0100, Ronny H. Kavli wrote:
> I've been running btrfs on some disks with Ubuntu kernel 2.6.31 for a
> while now. Recently I had a bad USB-cable to one of those disks which
> left the btrfs filesystem in a somewhat sad state. Fair enough.
>
> What worries me is what btrfsck reports back to me during two successive
> runs:
> root@bollox:/home/kavli# btrfsck /dev/mapper/vg3-vbox1
> checksum verify failed on 142837022720 wanted 5D18D333 found 95085E8
> checksum verify failed on 142837022720 wanted 5D18D333 found 95085E8
> checksum verify failed on 142837022720 wanted 5D18D333 found 95085E8
> btrfsck: disk-io.c:741: open_ctree_fd: Assertion `!(!tree_root->node)'
> failed.
> Aborted
> root@bollox:/home/kavli# btrfsck /dev/mapper/vg3-vbox1
> checksum verify failed on 142837022720 wanted 5D18D333 found 81D15E8
> checksum verify failed on 142837022720 wanted 5D18D333 found 81D15E8
> checksum verify failed on 142837022720 wanted 5D18D333 found 81D15E8
> btrfsck: disk-io.c:741: open_ctree_fd: Assertion `!(!tree_root->node)'
> failed.
> Aborted
>
> I'd expected the checksums for the two separate runs to be equal.
>
> This is a vanilla filesystem that resides on one physical disk:
> root@bollox:/home/kavli# btrfs-show /dev/mapper/vg3-vbox1
> failed to read /dev/sr0
> Label: none uuid: 08078f2f-22e0-4b79-8367-66528791afff
> Total devices 1 FS bytes used 106.79GB
> devid 1 size 232.88GB used 218.04GB
> path /dev/mapper/vg3-vbox1
>
> Btrfs Btrfs v0.19
>
> I've googled a bit and found one case with a similar problem in a raid1
> setup (I guess incorrectly stated as raid0):
> http://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg03429.html
>
> There were no followups beyond that point which stated the cause of this
> behaviour.

I haven't been able to reproduce it locally, but I definitely think it
sounds like the same problem. Have you tried the btrfs-map-logical
program in the unstable btrfs-progs repo?

-chris