xfs: enable logged file mapping exchange feature

Add the XFS_SB_FEAT_INCOMPAT_EXCHRANGE feature to the set of features
that we will permit when mounting a filesystem.  This turns on support
for the file range exchange feature.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/libxfs/xfs_format.h

@@ -380,7 +380,8 @@ xfs_sb_has_ro_compat_feature(
 		 XFS_SB_FEAT_INCOMPAT_META_UUID | \
 		 XFS_SB_FEAT_INCOMPAT_BIGTIME | \
 		 XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR | \
-		 XFS_SB_FEAT_INCOMPAT_NREXT64)
+		 XFS_SB_FEAT_INCOMPAT_NREXT64 | \
+		 XFS_SB_FEAT_INCOMPAT_EXCHRANGE)
 
 #define XFS_SB_FEAT_INCOMPAT_UNKNOWN	~XFS_SB_FEAT_INCOMPAT_ALL
 static inline bool