xfs: refactor superblock verifiers

Split the superblock verifier into the common checks, the read-time
checks, and the write-time check functions.  No functional changes, but
we're setting up to add more write-only checks.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
1 file changed