xfs_scrub: allow sysadmin to control background scrubs

Add an extended option -o autofsck to xfs_scrub so that it selects the
operation mode from the "autofsck" filesystem property.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
5 files changed