xfs: add reflink feature flag to geometry

Report the reflink feature in the XFS geometry so that xfs_info and
friends know the filesystem has this feature.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/libxfs/xfs_fs.h

@@ -206,7 +206,8 @@ typedef struct xfs_fsop_resblks {
 #define XFS_FSOP_GEOM_FLAGS_FTYPE	0x10000	/* inode directory types */
 #define XFS_FSOP_GEOM_FLAGS_FINOBT	0x20000	/* free inode btree */
 #define XFS_FSOP_GEOM_FLAGS_SPINODES	0x40000	/* sparse inode chunks	*/
-#define XFS_FSOP_GEOM_FLAGS_RMAPBT	0x80000	/* Reverse mapping btree */
+#define XFS_FSOP_GEOM_FLAGS_RMAPBT	0x80000	/* reverse mapping btree */
+#define XFS_FSOP_GEOM_FLAGS_REFLINK	0x100000 /* files can share blocks */
 
 /*
  * Minimum and maximum sizes need for growth checks.

fs/xfs/xfs_fsops.c

@@ -108,7 +108,9 @@ xfs_fs_geometry(
 			(xfs_sb_version_hassparseinodes(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_SPINODES : 0) |
 			(xfs_sb_version_hasrmapbt(&mp->m_sb) ?
-				XFS_FSOP_GEOM_FLAGS_RMAPBT : 0);
+				XFS_FSOP_GEOM_FLAGS_RMAPBT : 0) |
+			(xfs_sb_version_hasreflink(&mp->m_sb) ?
+				XFS_FSOP_GEOM_FLAGS_REFLINK : 0);
 		geo->logsectsize = xfs_sb_version_hassector(&mp->m_sb) ?
 				mp->m_sb.sb_logsectsize : BBSIZE;
 		geo->rtsectsize = mp->m_sb.sb_blocksize;