xfs: don't perform lookups on zero-height btrees
authorDarrick J. Wong <darrick.wong@oracle.com>
Fri, 26 Aug 2016 05:58:40 +0000 (15:58 +1000)
committerDave Chinner <david@fromorbit.com>
Fri, 26 Aug 2016 05:58:40 +0000 (15:58 +1000)
commited150e1a5cf20c04cf0b2d2c34e498fc1d6519be
tree867b5a19de18ad47ece6325be6ce8c6f986aaafd
parent32438cf9d54bd53b531f6d98814e84dd278360c1
xfs: don't perform lookups on zero-height btrees

If the caller passes in a cursor to a zero-height btree (which is
impossible), we never set block to anything but NULL, which causes the
later dereference of it to crash.  Instead, just return -EFSCORRUPTED.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
fs/xfs/libxfs/xfs_btree.c