Problem with btrfsck / couurpted filesystem

Hello,

I'm trying to fix a btrfs file system. BTRFSCK reports errors in the extend tree.
I've tryong to use --repair option but it ended up with an assertion failure.

I'm also trying to understand how the filesystem can have become corrupted. I'm running Ubuntu 12.10.

Any suggestion on ways to fix the problem would be really appreciated.

Regards, Stéphane.

Are you using the btrfs-progs from git? If not pull that down and build it and run the btrfsck in there, and then capture the output if it fails. Thanks,

Josef

Hi,

I've built the GIT tools and run btrfsck (without options) following the wiki page.
I got the following log:
Checking filesystem on /dev/VG_NL-SAS/LV_snap
UUID: de300fd0-1251-4767-9d80-84ce7ebfba9a
checking extents
checking free space cache
free space inode generation (0) did not match free space cache generation (16583)
free space inode generation (0) did not match free space cache generation (16579)
checking fs roots
checking csums
checking root refs
found 120489896006 bytes used err is 0
total csum bytes: 380818020
total tree bytes: 10396295168
total fs tree bytes: 9423839232
total extent tree bytes: 473616384
btree space waste bytes: 1923163802
file data blocks allocated: 455172272128
referenced 564086325248
Btrfs v0.20-rc1-335-gf00dd83

It does not report any extends error. Can I consider all is fine now?

Regards, Stéphane.

Yup. If you still have problems its likely just a kernel bug and not a corruption problem. And if that's the case dmesg would be nice so we can see whats going on. Thanks,

Josef

Thanks a lot for the support.

The fs metadata allocation was full. I did the balance operation and things seem to be back to normal.

It is a bit confusing and hard to predict when the fs is close to running out of space on one of its pool. I still had 60GB+ free data space when it happened.

The only thing I found in dmesg is:

Jun 27 16:33:56 lgin0001 kernel: [ 9225.057991] INFO: task
btrfs-transacti:9832 blocked for more than 120 seconds.
Jun 27 16:33:56 lgin0001 kernel: [ 9225.057995] "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jun 27 16:33:56 lgin0001 kernel: [ 9225.057998] btrfs-transacti D
ffff8806172939c0     0  9832      2 0x00000000
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058003]  ffff8803b68a3d90
0000000000000046 ffff88041b3e5c00 ffff8803b68a3fd8
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058008]  ffff8803b68a3fd8
ffff8803b68a3fd8 ffff88060d470000 ffff88041b3e5c00
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058012]  ffff8803b68a3da0
ffff8802e6d04000 ffff88020a8f2d20 ffff88020a8f2c00
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058017] Call Trace:
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058026]  [<ffffffff81681259>]
schedule+0x29/0x70
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058061]  [<ffffffffa013956d>]
wait_current_trans.isra.25+0x9d/0x100 [btrfs]
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058067]  [<ffffffff81076920>] ?
finish_wait+0x80/0x80
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058086]  [<ffffffffa013acb0>]
start_transaction+0x1f0/0x300 [btrfs]
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058092]  [<ffffffff810620e0>] ?
usleep_range+0x50/0x50
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058112]  [<ffffffffa013ae15>]
btrfs_join_transaction+0x15/0x20 [btrfs]
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058130]  [<ffffffffa0133047>]
transaction_kthread+0x147/0x2d0 [btrfs]
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058148]  [<ffffffffa0132f00>] ?
btree_readpage_end_io_hook+0x290/0x290 [btrfs]
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058152]  [<ffffffff81075f83>]
kthread+0x93/0xa0
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058157]  [<ffffffff8168b724>]
kernel_thread_helper+0x4/0x10
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058161]  [<ffffffff81075ef0>] ?
kthread_freezable_should_stop+0x70/0x70
Jun 27 16:33:56 lgin0001 kernel: [ 9225.058164]  [<ffffffff8168b720>] ?

gs_change+0x13/0x13

and logs about relocating block groups that I believe are linked to the balance operation.

Regards, Stéphane.