xfs_db: access realtime file blocks

Now that we have the ability to point the io cursor at the realtime
device, let's make it so that the "dblock" command can walk the contents
of realtime files.

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