Re: EXT4-fs error (device dm-42): ext4_mb_generate_buddy:741: group 1904, 32254 clusters in bitmap, 32258 in gd
From: Sander Eikelenboom
Date: Wed Jun 06 2012 - 03:01:29 EST
Hello Ted,
Another thing that thought of that could be of interest, i think this was a ext3 converted to ext4 partition.
Don't know if that is true for the other reports as well though.
--
Sander
Tuesday, June 5, 2012, 11:08:06 PM, you wrote:
> On Tue, Jun 05, 2012 at 10:41:54PM +0200, Sander Eikelenboom wrote:
>>
>> > Today I've finally managed to bisect this to here:
>> > [fd034a84e1ea5c8c8d159cd2089c32e792c269b0] ext4: split out ext4_free_blocks_after_init()
>>
>> > If I revert all the "ext4:" patches in 3.2 up to and including that one,
>> > I get normal behavior again.
> This is excellent. Thanks! I'll take a deep look at that ocmmit to
> see what might be going on.
>> So somehow this only effects ext4 on DM (it's THE common factor in all reports) and fsck seems incapable of seeing the error (and thus repair it.)
> What's probably happening is it's only the in-memory copy of the
> bitmap which is getting corrupted, and because the file system is
> getting remounted read-only, the corrupted bitmap is not getting
> written back to disk. (This is the whole point of remount-ro when fs
> corruptions are detected. :-)
> Cheers,
> - Ted
--
Best regards,
Sander mailto:linux@xxxxxxxxxxxxxx
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