[PATCH] xfs: don't skip rtmount when there's a realtime device

["Darrick J. Wong" <darrick.wong@oracle.com>]

From: Darrick J. Wong <darrick.wong@oracle.com>

Don't ever skip the realtime bitmap / summary inode initialization if
there's a realtime device attached, because we'd rather fail the mount
if iget declines to retrieve a NULL inode pointer.  Right now, if
someone sets rbmino to NULLFSINO on a rt-capable filesystem, mounts it,
and writes a file to the rt device, we'll blow up.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_rtalloc.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index aefd63d46397..18ad31ded0bf 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -1206,7 +1206,8 @@ xfs_rtmount_inodes(
 	xfs_sb_t	*sbp;
 
 	sbp = &mp->m_sb;
-	if (sbp->sb_rbmino == NULLFSINO)
+	if (!xfs_sb_version_hasrealtime(&mp->m_sb) &&
+	    sbp->sb_rbmino == NULLFSINO)
 		return 0;
 	error = xfs_iget(mp, NULL, sbp->sb_rbmino, 0, 0, &mp->m_rbmip);
 	if (error)