Merge branch 'work.namespace' into for-linus

Al Viro · Al Viro · commit faf0dcebd7b3 · 2016-12-22T23:04:31.000-05:00
diff --git a/fs/namespace.c b/fs/namespace.c
@@ -96,10 +96,6 @@ static inline struct hlist_head *mp_hash(struct dentry *dentry)
 	return &mountpoint_hashtable[tmp & mp_hash_mask];
 }
 
-/*
- * allocation is serialized by namespace_sem, but we need the spinlock to
- * serialize with freeing.
- */
 static int mnt_alloc_id(struct mount *mnt)
 {
 	int res;
@@ -1034,6 +1030,8 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
 		if (IS_MNT_SLAVE(old))
 			list_add(&mnt->mnt_slave, &old->mnt_slave);
 		mnt->mnt_master = old->mnt_master;
+	} else {
+		CLEAR_MNT_SHARED(mnt);
 	}
 	if (flag & CL_MAKE_SHARED)
 		set_mnt_shared(mnt);
@@ -1828,9 +1826,7 @@ struct vfsmount *clone_private_mount(const struct path *path)
 	if (IS_MNT_UNBINDABLE(old_mnt))
 		return ERR_PTR(-EINVAL);
 
-	down_read(&namespace_sem);
 	new_mnt = clone_mnt(old_mnt, path->dentry, CL_PRIVATE);
-	up_read(&namespace_sem);
 	if (IS_ERR(new_mnt))
 		return ERR_CAST(new_mnt);
 
diff --git a/fs/pnode.c b/fs/pnode.c
@@ -67,49 +67,47 @@ 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 = mnt->mnt_master;
-	struct mount *slave_mnt;
+	struct mount *master, *slave_mnt;
 
-	/*
-	 * slave 'mnt' to a peer mount that has the
-	 * same root dentry. If none is available then
-	 * slave it to anything that is available.
-	 */
-	while ((peer_mnt = next_peer(peer_mnt)) != mnt &&
-	       peer_mnt->mnt.mnt_root != mnt->mnt.mnt_root) ;
-
-	if (peer_mnt == mnt) {
-		peer_mnt = next_peer(mnt);
-		if (peer_mnt == mnt)
-			peer_mnt = NULL;
-	}
-	if (mnt->mnt_group_id && IS_MNT_SHARED(mnt) &&
-	    list_empty(&mnt->mnt_share))
-		mnt_release_group_id(mnt);
-
-	list_del_init(&mnt->mnt_share);
-	mnt->mnt_group_id = 0;
-
-	if (peer_mnt)
-		master = peer_mnt;
-
-	if (master) {
-		list_for_each_entry(slave_mnt, &mnt->mnt_slave_list, mnt_slave)
-			slave_mnt->mnt_master = master;
-		list_move(&mnt->mnt_slave, &master->mnt_slave_list);
-		list_splice(&mnt->mnt_slave_list, master->mnt_slave_list.prev);
-		INIT_LIST_HEAD(&mnt->mnt_slave_list);
+	if (list_empty(&mnt->mnt_share)) {
+		if (IS_MNT_SHARED(mnt)) {
+			mnt_release_group_id(mnt);
+			CLEAR_MNT_SHARED(mnt);
+		}
+		master = mnt->mnt_master;
+		if (!master) {
+			struct list_head *p = &mnt->mnt_slave_list;
+			while (!list_empty(p)) {
+				slave_mnt = list_first_entry(p,
+						struct mount, mnt_slave);
+				list_del_init(&slave_mnt->mnt_slave);
+				slave_mnt->mnt_master = NULL;
+			}
+			return 0;
+		}
 	} else {
-		struct list_head *p = &mnt->mnt_slave_list;
-		while (!list_empty(p)) {
-                        slave_mnt = list_first_entry(p,
-					struct mount, mnt_slave);
-			list_del_init(&slave_mnt->mnt_slave);
-			slave_mnt->mnt_master = NULL;
+		struct mount *m;
+		/*
+		 * slave 'mnt' to a peer mount that has the
+		 * same root dentry. If none is available then
+		 * slave it to anything that is available.
+		 */
+		for (m = master = next_peer(mnt); m != mnt; m = next_peer(m)) {
+			if (m->mnt.mnt_root == mnt->mnt.mnt_root) {
+				master = m;
+				break;
+			}
 		}
+		list_del_init(&mnt->mnt_share);
+		mnt->mnt_group_id = 0;
+		CLEAR_MNT_SHARED(mnt);
 	}
+	list_for_each_entry(slave_mnt, &mnt->mnt_slave_list, mnt_slave)
+		slave_mnt->mnt_master = master;
+	list_move(&mnt->mnt_slave, &master->mnt_slave_list);
+	list_splice(&mnt->mnt_slave_list, master->mnt_slave_list.prev);
+	INIT_LIST_HEAD(&mnt->mnt_slave_list);
 	mnt->mnt_master = master;
-	CLEAR_MNT_SHARED(mnt);
 	return 0;
 }
 
