xfs: enable metadata directory feature

Enable the metadata directory feature.  With this feature, all metadata
inodes are placed in the metadata directory, and the only inumbers in
the superblock are the roots of the two directory trees.

The RT device is now sharded into a number of rtgroups, where 0 rtgroups
mean that no RT extents are supported, and the traditional XFS stub RT
bitmap and summary inodes don't exist.  A single rtgroup gives roughly
identical behavior to the traditional RT setup, but now with checksummed
and self identifying free space metadata.

For quota, the quota options are read from the superblock unless
explicitly overridden via mount options.

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

diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index eabafde6f9f431a8b851340d2d6cd321e7e7e373..df392c30c14e34460223b2b292947ae7ab147d9d 100644 (file)
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -397,7 +397,8 @@ xfs_sb_has_ro_compat_feature(
                 XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR | \
                 XFS_SB_FEAT_INCOMPAT_NREXT64 | \
                 XFS_SB_FEAT_INCOMPAT_EXCHRANGE | \
-                XFS_SB_FEAT_INCOMPAT_PARENT)
+                XFS_SB_FEAT_INCOMPAT_PARENT | \
+                XFS_SB_FEAT_INCOMPAT_METADIR)
 
 #define XFS_SB_FEAT_INCOMPAT_UNKNOWN   ~XFS_SB_FEAT_INCOMPAT_ALL
 static inline bool