Rework MOUNTED/DOING SOFTDEP/SUJ macros

Now MNT_SOFTDEP indicates that SU are active in any variant +-J, and
SU+J is indicated by MNT_SOFTDEP | MNT_SUJ combination.  The reason is
that unmount will be able to easily hide SU from other operations by
clearing MNT_SOFTDEP while keeping the record of the active journal.

Reviewed by:	mckusick
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
Differential revision:	https://reviews.freebsd.org/D29178

sys/ufs/ffs/ffs_softdep.c

@@ -3024,7 +3024,6 @@ journal_mount(mp, fs, cred)
 
 	MNT_ILOCK(mp);
 	mp->mnt_flag |= MNT_SUJ;
-	mp->mnt_flag &= ~MNT_SOFTDEP;
 	MNT_IUNLOCK(mp);
 
 	/*

sys/ufs/ufs/inode.h

@@ -265,11 +265,11 @@ struct indir {
 #define	ITOV(ip)	((ip)->i_vnode)
 
 /* Determine if soft dependencies are being done */
-#define	DOINGSOFTDEP(vp)   \
-	(((vp)->v_mount->mnt_flag & (MNT_SOFTDEP | MNT_SUJ)) != 0)
-#define	MOUNTEDSOFTDEP(mp) (((mp)->mnt_flag & (MNT_SOFTDEP | MNT_SUJ)) != 0)
-#define	DOINGSUJ(vp)	   (((vp)->v_mount->mnt_flag & MNT_SUJ) != 0)
-#define	MOUNTEDSUJ(mp)	   (((mp)->mnt_flag & MNT_SUJ) != 0)
+#define	MOUNTEDSOFTDEP(mp)	(((mp)->mnt_flag & MNT_SOFTDEP) != 0)
+#define	DOINGSOFTDEP(vp)	MOUNTEDSOFTDEP((vp)->v_mount)
+#define	MOUNTEDSUJ(mp)		(((mp)->mnt_flag & (MNT_SOFTDEP | MNT_SUJ)) == \
+    (MNT_SOFTDEP | MNT_SUJ))
+#define	DOINGSUJ(vp)		MOUNTEDSUJ((vp)->v_mount)
 
 /* This overlays the fid structure (see mount.h). */
 struct ufid {