Messages in this thread | | | Date | Tue, 5 Jun 2012 23:35:14 +0200 | From | Sander Eikelenboom <> | Subject | Re: EXT4-fs error (device dm-42): ext4_mb_generate_buddy:741: group 1904, 32254 clusters in bitmap, 32258 in gd |
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Hello Ted,
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. :-)
The commits Kees pointed too, made me:
- Copy files to the fs and trigger the error. - "fsck -v -f", no errors where reported, only journal recovered. - "tune2fs -O ^uninit_bg" on the fs. - "fsck -v -f", which found some bitmap size errors now, let it fix these. - Mounted the fs - Copy the same set of files, no error has occured.
So it seems related to the uninit_bg changes in the commits on 10 september 2011.
-- Sander
> Cheers,
> - Ted
-- Best regards, Sander mailto:linux@eikelenboom.it
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