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authorMark Tinguely <tinguely@sgi.com>2014-04-04 07:10:49 +1100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-04-26 17:19:05 -0700
commit7de24f7b0ddb815d7a8375354a9612264092edcb (patch)
parent1c23ab6f8860f1d5823868d868314f674333a8b3 (diff)
xfs: fix directory hash ordering bug
commit c88547a8119e3b581318ab65e9b72f27f23e641d upstream. Commit f5ea1100 ("xfs: add CRCs to dir2/da node blocks") introduced in 3.10 incorrectly converted the btree hash index array pointer in xfs_da3_fixhashpath(). It resulted in the the current hash always being compared against the first entry in the btree rather than the current block index into the btree block's hash entry array. As a result, it was comparing the wrong hashes, and so could misorder the entries in the btree. For most cases, this doesn't cause any problems as it requires hash collisions to expose the ordering problem. However, when there are hash collisions within a directory there is a very good probability that the entries will be ordered incorrectly and that actually matters when duplicate hashes are placed into or removed from the btree block hash entry array. This bug results in an on-disk directory corruption and that results in directory verifier functions throwing corruption warnings into the logs. While no data or directory entries are lost, access to them may be compromised, and attempts to remove entries from a directory that has suffered from this corruption may result in a filesystem shutdown. xfs_repair will fix the directory hash ordering without data loss occuring. [dchinner: wrote useful a commit message] Reported-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: Mark Tinguely <tinguely@sgi.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/xfs/xfs_da_btree.c b/fs/xfs/xfs_da_btree.c
index 796272a2e129..e69d57be866b 100644
--- a/fs/xfs/xfs_da_btree.c
+++ b/fs/xfs/xfs_da_btree.c
@@ -1295,7 +1295,7 @@ xfs_da3_fixhashpath(
node = blk->bp->b_addr;
dp->d_ops->node_hdr_from_disk(&nodehdr, node);
btree = dp->d_ops->node_tree_p(node);
- if (be32_to_cpu(btree->hashval) == lasthash)
+ if (be32_to_cpu(btree[blk->index].hashval) == lasthash)
blk->hashval = lasthash;
btree[blk->index].hashval = cpu_to_be32(lasthash);