xfs: improve rt metadata use for scrub This short series makes some small changes to the way we handle the realtime metadata inodes. First, we now make sure that the bitmap and summary file forks are always loaded at mount time so that every scrubber won't have to call xfs_iread_extents. This won't be easy if we're, say, cross-referencing realtime space allocations. The second change makes the ILOCK annotations more consistent with the rest of XFS. Signed-off-by: Darrick J. Wong <djwong@kernel.org>