xfs: disallow mounting of realtime + rmap filesystems

Since the kernel doesn't currently support the realtime rmapbt,
don't allow such filesystems to be mounted.  Support will appear
in a future release.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 24ef83ef04de..fd6be45b3a1e 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1574,9 +1574,16 @@ xfs_fs_fill_super(
                 }
         }
 
-        if (xfs_sb_version_hasrmapbt(&mp->m_sb))
+        if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
+                if (mp->m_sb.sb_rblocks) {
+                        xfs_alert(mp,
+        "EXPERIMENTAL reverse mapping btree not compatible with realtime device!");
+                        error = -EINVAL;
+                        goto out_filestream_unmount;
+                }
                 xfs_alert(mp,
         "EXPERIMENTAL reverse mapping btree feature enabled. Use at your own risk!");
+        }
 
         error = xfs_mountfs(mp);
         if (error)