xfs: don't crash if reading a directory results in an unexpected hole
authorDarrick J. Wong <darrick.wong@oracle.com>
Mon, 5 Dec 2016 01:37:47 +0000 (12:37 +1100)
committerDave Chinner <david@fromorbit.com>
Mon, 5 Dec 2016 01:37:47 +0000 (12:37 +1100)
commit96a3aefb8ffde23180130460b0b2407b328eb727
tree95c3b9855e5423120a04f9b92612b3e212e63bd8
parent356a3225222e5bc4df88aef3419fb6424f18ab69
xfs: don't crash if reading a directory results in an unexpected hole

In xfs_dir3_data_read, we can encounter the situation where err == 0 and
*bpp == NULL if the given bno offset happens to be a hole; this leads to
a crash if we try to set the buffer type after the _da_read_buf call.
Holes can happen due to corrupt or malicious entries in the bmbt data,
so be a little more careful when we're handling buffers.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
fs/xfs/libxfs/xfs_dir2_data.c