Andras Korn reported an oops on log replay causes by a corrupted
xfs_inode_log_format_t passing a 0 size to kmem_zalloc.  This patch handles
to small or too large numbers of log regions gracefully by rejecting the
log replay with a useful error message.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reported-by: NAndras Korn <korn-sgi.com@chardonnay.math.bme.hu>
Reviewed-by: NEric Sandeen <sandeen@sandeen.net>
Signed-off-by: NFelix Blyakher <felixb@sgi.com>