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Message-id: <20090311003845.GB3199@webber.adilger.int> Date: Tue, 10 Mar 2009 18:38:45 -0600 From: Andreas Dilger <adilger@....com> To: Theodore Tso <tytso@....edu> Cc: Kevin Shanahan <kmshanah@...b.org.au>, Eric Sandeen <sandeen@...hat.com>, linux-ext4@...r.kernel.org Subject: Re: Possible ext4 corruption - ACL related? On Mar 10, 2009 18:48 -0400, Theodore Ts'o wrote: > On Wed, Mar 11, 2009 at 07:44:51AM +1030, Kevin Shanahan wrote: > > Thanks Ted. Just so I know what I'm doing if/when this comes up again, I > > guess the process would be: > > > > - debugfs /dev/some-filesystem > > - debugfs: stat "some/problem/file" > > - get the inode number from the output above (867 in this case) > > - debugfs dump 867 inode867.bin > > Actually, it's a bit more complicated than that. I should really add > a hook to debugfs to automate this, but... to find the block to grab, > you do this. [many complex steps deleted] > So now we know that the block containing inode 867 is 65+54 = 119 Or you can use imap (which Ted probably wrote in the first place. :-) debugfs: imap some/problem/file Inode 867 is part of block group 0 located at block 119, offset 0x0180 > Now to dump that block, we do: > > dd if=/dev/fs-device of=block-119.dump bs=4k skip=119 count=1 This part is the same. > > Or perhaps running e2fsck -n first to see which inodes really look > > corrupted and get the numbers that way. > > Yep. In general, when you get corruption like this, the bad inodes > comes in chunks of 16 (if you are using 256 byte inodes) or 32 (if you > are using 128 byte inodes). Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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