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 Date: Wed, 6 Jun 2012 09:01:26 +0200 Message-ID: <1883708187.20120606090126@eikelenboom.it> References: <471046920.20120604234941@eikelenboom.it> <20120605000356.GM29466@outflux.net> <1018371644.20120605224154@eikelenboom.it> <20120605210806.GB7182@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: Kees Cook , Linus Torvalds , , , To: Ted Ts'o Return-path: In-Reply-To: <20120605210806.GB7182@thunk.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org 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@eikelenboom.it