vfs: take mnt_master to struct mount

make IS_MNT_SLAVE take struct mount * at the same time
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/mount.h

@@ -19,6 +19,8 @@ struct mount {
 #endif
 	struct list_head mnt_mounts;	/* list of children, anchored here */
 	struct list_head mnt_child;	/* and going through their mnt_child */
+	/* yet to be moved - up to mnt_slave */
+	struct vfsmount *mnt_master;	/* slave is on master->mnt_slave_list */
 };
 
 static inline struct mount *real_mount(struct vfsmount *mnt)

fs/namespace.c

@@ -715,14 +715,14 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
 
 		if (flag & CL_SLAVE) {
 			list_add(&mnt->mnt.mnt_slave, &old->mnt.mnt_slave_list);
-			mnt->mnt.mnt_master = &old->mnt;
+			mnt->mnt_master = &old->mnt;
 			CLEAR_MNT_SHARED(&mnt->mnt);
 		} else if (!(flag & CL_PRIVATE)) {
 			if ((flag & CL_MAKE_SHARED) || IS_MNT_SHARED(&old->mnt))
 				list_add(&mnt->mnt.mnt_share, &old->mnt.mnt_share);
-			if (IS_MNT_SLAVE(&old->mnt))
+			if (IS_MNT_SLAVE(old))
 				list_add(&mnt->mnt.mnt_slave, &old->mnt.mnt_slave);
-			mnt->mnt.mnt_master = old->mnt.mnt_master;
+			mnt->mnt_master = old->mnt_master;
 		}
 		if (flag & CL_MAKE_SHARED)
 			set_mnt_shared(mnt);
@@ -1051,8 +1051,8 @@ static int show_mountinfo(struct seq_file *m, void *v)
 	/* Tagged fields ("foo:X" or "bar") */
 	if (IS_MNT_SHARED(mnt))
 		seq_printf(m, " shared:%i", mnt->mnt_group_id);
-	if (IS_MNT_SLAVE(mnt)) {
-		int master = mnt->mnt_master->mnt_group_id;
+	if (IS_MNT_SLAVE(r)) {
+		int master = r->mnt_master->mnt_group_id;
 		int dom = get_dominating_id(r, &p->root);
 		seq_printf(m, " master:%i", master);
 		if (dom && dom != master)

fs/pnode.c

@@ -55,7 +55,7 @@ int get_dominating_id(struct mount *mnt, const struct path *root)
 {
 	struct mount *m;
 
-	for (m = real_mount(mnt->mnt.mnt_master); m != NULL; m = real_mount(m->mnt.mnt_master)) {
+	for (m = real_mount(mnt->mnt_master); m != NULL; m = real_mount(m->mnt_master)) {
 		struct mount *d = get_peer_under_root(m, mnt->mnt.mnt_ns, root);
 		if (d)
 			return d->mnt.mnt_group_id;
@@ -66,8 +66,8 @@ int get_dominating_id(struct mount *mnt, const struct path *root)
 
 static int do_make_slave(struct mount *mnt)
 {
-	struct mount *peer_mnt = mnt, *master = real_mount(mnt->mnt.mnt_master);
-	struct vfsmount *slave_mnt;
+	struct mount *peer_mnt = mnt, *master = real_mount(mnt->mnt_master);
+	struct mount *slave_mnt;
 
 	/*
 	 * slave 'mnt' to a peer mount that has the
@@ -92,7 +92,7 @@ static int do_make_slave(struct mount *mnt)
 		master = peer_mnt;
 
 	if (master) {
-		list_for_each_entry(slave_mnt, &mnt->mnt.mnt_slave_list, mnt_slave)
+		list_for_each_entry(slave_mnt, &mnt->mnt.mnt_slave_list, mnt.mnt_slave)
 			slave_mnt->mnt_master = &master->mnt;
 		list_move(&mnt->mnt.mnt_slave, &master->mnt.mnt_slave_list);
 		list_splice(&mnt->mnt.mnt_slave_list, master->mnt.mnt_slave_list.prev);
@@ -101,12 +101,12 @@ static int do_make_slave(struct mount *mnt)
 		struct list_head *p = &mnt->mnt.mnt_slave_list;
 		while (!list_empty(p)) {
                         slave_mnt = list_first_entry(p,
-					struct vfsmount, mnt_slave);
-			list_del_init(&slave_mnt->mnt_slave);
+					struct mount, mnt.mnt_slave);
+			list_del_init(&slave_mnt->mnt.mnt_slave);
 			slave_mnt->mnt_master = NULL;
 		}
 	}
-	mnt->mnt.mnt_master = &master->mnt;
+	mnt->mnt_master = &master->mnt;
 	CLEAR_MNT_SHARED(&mnt->mnt);
 	return 0;
 }
@@ -123,7 +123,7 @@ void change_mnt_propagation(struct mount *mnt, int type)
 	do_make_slave(mnt);
 	if (type != MS_SLAVE) {
 		list_del_init(&mnt->mnt.mnt_slave);
-		mnt->mnt.mnt_master = NULL;
+		mnt->mnt_master = NULL;
 		if (type == MS_UNBINDABLE)
 			mnt->mnt.mnt_flags |= MNT_UNBINDABLE;
 		else
@@ -149,9 +149,9 @@ static struct mount *propagation_next(struct mount *m,
 		return first_slave(m);
 
 	while (1) {
-		struct mount *master = real_mount(m->mnt.mnt_master);
+		struct mount *master = real_mount(m->mnt_master);
 
-		if (&master->mnt == origin->mnt.mnt_master) {
+		if (&master->mnt == origin->mnt_master) {
 			struct mount *next = next_peer(m);
 			return (next == origin) ? NULL : next;
 		} else if (m->mnt.mnt_slave.next != &master->mnt.mnt_slave_list)
@@ -179,11 +179,11 @@ static struct mount *get_source(struct mount *dest,
 	struct mount *p_last_src = NULL;
 	struct mount *p_last_dest = NULL;
 
-	while (&last_dest->mnt != dest->mnt.mnt_master) {
+	while (&last_dest->mnt != dest->mnt_master) {
 		p_last_dest = last_dest;
 		p_last_src = last_src;
-		last_dest = real_mount(last_dest->mnt.mnt_master);
-		last_src = real_mount(last_src->mnt.mnt_master);
+		last_dest = real_mount(last_dest->mnt_master);
+		last_src = real_mount(last_src->mnt_master);
 	}
 
 	if (p_last_dest) {

include/linux/mount.h

@@ -62,7 +62,6 @@ struct vfsmount {
 	struct list_head mnt_share;	/* circular list of shared mounts */
 	struct list_head mnt_slave_list;/* list of slave mounts */
 	struct list_head mnt_slave;	/* slave list entry */
-	struct vfsmount *mnt_master;	/* slave is on master->mnt_slave_list */
 	struct mnt_namespace *mnt_ns;	/* containing namespace */
 	int mnt_id;			/* mount identifier */
 	int mnt_group_id;		/* peer group identifier */