btrfsck --repair --init-extent-tree: segfault error 4

[Martin <m_btrfs@ml1.co.uk>]

Any clues or educated comment please?

Can the corrupt directory tree safely be ignored and left in place? Or
might that cause everything to fall over in a big heap as soon as I try
to write data again?


Could these other tricks work-around or fix the corrupt tree:

Run a scrub?

Make a snapshot and work from the snapshot?

Or try "mount -o recovery,noatime" again?


Or is it dead?

(The 1.5TB of backup data is replicated elsewhere but it would be good
to rescue this version rather than completely redo from scratch.
Especially so for the sake of just a few MBytes of one corrupt directory
tree.)

Thanks,
Martin



On 05/10/13 14:18, Martin wrote:
> So...
> 
> The hint there is "btrfsck: extent-tree.c:2736", so trying:
> 
> btrfsck --repair --init-extent-tree /dev/sdc
> 
> That ran for a while until:
> 
> kernel: btrfsck[16610]: segfault at cc ip 000000000041d2a7 sp
> 00007fffd2c2d710 error 4 in btrfsck[400000+4d000]
> 
> There's no other messages in the syslog.
> 
> The output attached.
> 
> 
> What next?
> 
> 
> Thanks,
> Martin
> 
> 
> 
> On 05/10/13 12:32, Martin wrote:
>> No comment so blindly trying:
>>
>> btrfsck --repair /dev/sdc
>>
>> gave the following abort:
>>
>> btrfsck: extent-tree.c:2736: alloc_reserved_tree_block: Assertion
>> `!(ret)' failed.
>>
>> Full output attached.
>>
>>
>> All on:
>>
>> 3.11.2-gentoo
>> Btrfs v0.20-rc1-358-g194aa4a
>>
>> For a 2TB single HDD formatted with defaults.
>>
>>
>> What next?
>>
>> Thanks,
>> Martin
>>
>>
>>
>>
>>>> In the meantime, trying:
>>>>
>>>> btrfsck /dev/sdc
>>>>
>>>> gave the following output + abort:
>>>>
>>>> parent transid verify failed on 915444523008 wanted 16974 found 13021
>>>> Ignoring transid failure
>>>> btrfsck: cmds-check.c:1066: process_file_extent: Assertion `!(rec->ino
>>>> != key->objectid || rec->refs > 1)' failed.
>>>> id not match free space cache generation (1625)
>>>> free space inode generation (0) did not match free space cache
>>>> generation (1607)
>>>> free space inode generation (0) did not match free space cache
>>>> generation (1604)
>>>> free space inode generation (0) did not match free space cache
>>>> generation (1606)
>>>> free space inode generation (0) did not match free space cache
>>>> generation (1620)
>>>> free space inode generation (0) did not match free space cache
>>>> generation (1626)
>>>> free space inode generation (0) did not match free space cache
>>>> generation (1609)
>>>> free space inode generation (0) did not match free space cache
>>>> generation (1653)
>>>> free space inode generation (0) did not match free space cache
>>>> generation (1628)
>>>> free space inode generation (0) did not match free space cache
>>>> generation (1628)
>>>> free space inode generation (0) did not match free space cache
>>>> generation (1649)
>>>>
>>>>
>>>> (There was no syslog output.)
>>>>
>>>> Full btrfsck listing attached.
>>>>
>>>>
>>>> Suggestions please?
>>>>
>>>> Thanks,
>>>> Martin