On 08/26/13 08:36, Brian Foster wrote:
On 08/26/2013 12:13 AM, Dave Chinner wrote:
On Thu, Aug 22, 2013 at 02:28:00PM -0400, Brian Foster wrote:
Hi all,
I hit an assert on a debug kernel while beating on some finobt work and
eventually reproduced it on unmodified/TOT xfs/xfsprogs as of today. I
hit it through a couple different paths, first while running fsstress on
a CRC enabled filesystem (with otherwise default mkfs options):
(These tests are running on a 4p, 4GB VM against a 100GB virtio disk,
hosted on a single spindle desktop box).
crc=1
fsstress -z -fsymlink=1 -n99999999 -p4 -d /mnt/test
XFS: Assertion failed: first<= last&& last< BBTOB(bp->b_length),
Directory buffer overrun.
[<ffffffffa031d549>] xfs_trans_log_buf+0x89/0x1b0 [xfs]
[<ffffffffa02e7c1c>] xfs_da3_node_add+0x11c/0x210 [xfs]
[<ffffffffa02ea703>] xfs_da3_node_split+0xc3/0x230 [xfs]
[<ffffffffa02eaa18>] xfs_da3_split+0x1a8/0x410 [xfs]
[<ffffffffa02f743f>] xfs_dir2_node_addname+0x47f/0xde0 [xfs]
During a split.
Easily reproduced with "seq 200000 | xargs touch" as Michael Semon
reported last week.
The fix demonstrates my concerns about modifying directory code -
the CRC changes missed a *fundamental* directory format definition,
and we've only just tripped over it....
I agree. As we see here, bugs in common directory code effect all
filesystems. It may not matter if the feature the code was written for
is enabled or not.
rm -rf /mnt/test
XFS: Assertion failed: first<= last&& last< BBTOB(bp->b_length),
Directory buffer overrun.
[<ffffffffa032b549>] xfs_trans_log_buf+0x89/0x1b0 [xfs]
[<ffffffffa02f61ff>] xfs_da3_node_unbalance+0xef/0x1d0 [xfs]
[<ffffffffa02f98b0>] xfs_da3_join+0x240/0x290 [xfs]
[<ffffffffa030659b>] xfs_dir2_node_removename+0x69b/0x8b0 [xfs]
During a merge. Not sure why that is happening on a v4 filesystem.
V5 filesystem, yes, due to the above bug but v4 should not be
affected.
Interesting, thanks Dave. FWIW, I no longer reproduce the assert in
either scenario with this patch applied. I also don't see how it would
make a difference for a v4 superblock filesystem. Perhaps that
particular test was bogus. I haven't heard if Mark happened to reproduce
that one. Regardless, consider it:
Tested-by: Brian Foster<bfoster@xxxxxxxxxx>
(xfs: fix calculation of the number of node entries in a dir3 node)
I got the XFS v4 to assert on the remove in Linux 3.10 and 3.11.
With the patch, a shorter test on Linux 3.10 did not assert. I will do
the full test on Linux 3.10/3.11, review and report back.
Brian
Cheers,
Dave.
--Mark.
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