xfs: add fsgeom flag for v5 superblock support.

Currently userspace has no way of determining that a filesystem is
CRC enabled. Add a flag to the XFS_IOC_FSGEOMETRY ioctl output to
indicate that the filesystem has v5 superblock support enabled.
This will allow xfs_info to correctly report the state of the
filesystem.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

fs/xfs/xfs_fs.h

@@ -236,6 +236,7 @@ typedef struct xfs_fsop_resblks {
 #define XFS_FSOP_GEOM_FLAGS_PROJID32	0x0800  /* 32-bit project IDs	*/
 #define XFS_FSOP_GEOM_FLAGS_DIRV2CI	0x1000	/* ASCII only CI names	*/
 #define XFS_FSOP_GEOM_FLAGS_LAZYSB	0x4000	/* lazy superblock counters */
+#define XFS_FSOP_GEOM_FLAGS_V5SB	0x8000	/* version 5 superblock */
 
 
 /*

fs/xfs/xfs_fsops.c

@@ -99,7 +99,9 @@ xfs_fs_geometry(
 			(xfs_sb_version_hasattr2(&mp->m_sb) ?
 				XFS_FSOP_GEOM_FLAGS_ATTR2 : 0) |
 			(xfs_sb_version_hasprojid32bit(&mp->m_sb) ?
-				XFS_FSOP_GEOM_FLAGS_PROJID32 : 0);
+				XFS_FSOP_GEOM_FLAGS_PROJID32 : 0) |
+			(xfs_sb_version_hascrc(&mp->m_sb) ?
+				XFS_FSOP_GEOM_FLAGS_V5SB : 0);
 		geo->logsectsize = xfs_sb_version_hassector(&mp->m_sb) ?
 				mp->m_sb.sb_logsectsize : BBSIZE;
 		geo->rtsectsize = mp->m_sb.sb_blocksize;