PROBLEM: XFS on ARM corruption 'Structure needs cleaning'

[Dave Chinner]

On Thu, Jun 11, 2015 at 03:07:45PM -0500, Eric Sandeen wrote:
> On 6/11/15 11:32 AM, Török Edwin wrote:
> > [4745016.650000] XFS (loop0): metadata I/O error: block 0xa000 ("xfs_trans_read_buf_map") error 117 numblks 8
> 
> ok, block 0xA000 (in sectors) is sector 40960...
> 
> xfs_db> daddr 40960
> xfs_db> fsblock 
> current fsblock is 8192
> xfs_db> type text
> xfs_db> p
> 000:  58 46 53 42 00 00 10 00 00 00 00 00 00 00 28 00  XFSB............
> 010:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> 020:  64 23 d2 06 32 2e 4c 20 82 6e f0 36 a7 d9 54 f9  d...2.L..n.6..T.
> 
> ...
> 
> Right, so it's reading the 2nd superblock in xfs_dir3_data_read_verify.  Huh?
> (I could have imagined some weird scenario where we read block 0, but 8192?
> Very strange).
> 
> Hm, I don't think this can be readahead, it'd not get to this verifier AFAICT.
> 
> Given that the image is enough to reproduce via just mount; ls - we should be
> able to reproduce this, given the right hardware, and get to the bottom of it.

OK, so I've had a look at the on disk layout via xfs_db and there is
no corruption present on disk. I've confirmed that by mounting on
x86-64 (on 4.1-rc6) and no errors have been issued, and xfs_repair
(from for-next branch) doesn't see anything wrong, either.

So this is looking like either: a) a kernel bug we've subsequently
fixed; or b) an arm specific compiler or kernel bug.

I'd like to see a) ruled out as quickly as possible. Torok, can you
build a more recent kernel and see if the problem persists?

Can you also let us know what compiler version you are using and how
you are compiling (e.g. cross compile)? ISTR a previous incarnation
of this problem showed up when a specific compiler version was used
to cross-compile the armv7 kernel from x86-64, and it went away with
a compiler update. So it would be good to rule out the
compiler/build environment as the cause, too.

Cheers,

Dave.
-- 
Dave Chinner
david at fromorbit.com