metadump: check for non-zero inode alignment

metadump: check for non-zero inode alignment

The copy_inode_chunk() function performs some basic sanity checks on the
inode record, block number, etc. One of these checks includes whether
the inode chunk is aligned according to sb_inoalignmt. sb_inoalignment
can equal 0 with larger block sizes. This results in a mod-by-zero,
"badly aligned inode ..." warnings and skipped inodes in metadump
images. This can be reproduced with a '-m crc=1,finobt=1 -b size=64k' fs
on ppc64.

Update copy_inode_chunk() to only enforce the inode alignment check when
sb_inoalignmt is non-zero.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>