1 files changed, 71 insertions, 35 deletions

diff --git a/fs/fsopen.c b/fs/fsopen.c
index fc9d2d9fd234..ce03f6521c88 100644
--- a/fs/fsopen.c
+++ b/fs/fsopen.c
@@ -209,6 +209,72 @@ err:
 	return ret;
 }
 
+static int vfs_cmd_create(struct fs_context *fc, bool exclusive)
+{
+	struct super_block *sb;
+	int ret;
+
+	if (fc->phase != FS_CONTEXT_CREATE_PARAMS)
+		return -EBUSY;
+
+	if (!mount_capable(fc))
+		return -EPERM;
+
+	/* require the new mount api */
+	if (exclusive && fc->ops == &legacy_fs_context_ops)
+		return -EOPNOTSUPP;
+
+	fc->phase = FS_CONTEXT_CREATING;
+	fc->exclusive = exclusive;
+
+	ret = vfs_get_tree(fc);
+	if (ret) {
+		fc->phase = FS_CONTEXT_FAILED;
+		return ret;
+	}
+
+	sb = fc->root->d_sb;
+	ret = security_sb_kern_mount(sb);
+	if (unlikely(ret)) {
+		fc_drop_locked(fc);
+		fc->phase = FS_CONTEXT_FAILED;
+		return ret;
+	}
+
+	/* vfs_get_tree() callchains will have grabbed @s_umount */
+	up_write(&sb->s_umount);
+	fc->phase = FS_CONTEXT_AWAITING_MOUNT;
+	return 0;
+}
+
+static int vfs_cmd_reconfigure(struct fs_context *fc)
+{
+	struct super_block *sb;
+	int ret;
+
+	if (fc->phase != FS_CONTEXT_RECONF_PARAMS)
+		return -EBUSY;
+
+	fc->phase = FS_CONTEXT_RECONFIGURING;
+
+	sb = fc->root->d_sb;
+	if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) {
+		fc->phase = FS_CONTEXT_FAILED;
+		return -EPERM;
+	}
+
+	down_write(&sb->s_umount);
+	ret = reconfigure_super(fc);
+	up_write(&sb->s_umount);
+	if (ret) {
+		fc->phase = FS_CONTEXT_FAILED;
+		return ret;
+	}
+
+	vfs_clean_context(fc);
+	return 0;
+}
+
 /*
  * Check the state and apply the configuration.  Note that this function is
  * allowed to 'steal' the value by setting param->xxx to NULL before returning.
@@ -216,7 +282,6 @@ err:
 static int vfs_fsconfig_locked(struct fs_context *fc, int cmd,
 			       struct fs_parameter *param)
 {
-	struct super_block *sb;
 	int ret;
 
 	ret = finish_clean_context(fc);
@@ -224,39 +289,11 @@ static int vfs_fsconfig_locked(struct fs_context *fc, int cmd,
 		return ret;
 	switch (cmd) {
 	case FSCONFIG_CMD_CREATE:
-		if (fc->phase != FS_CONTEXT_CREATE_PARAMS)
-			return -EBUSY;
-		if (!mount_capable(fc))
-			return -EPERM;
-		fc->phase = FS_CONTEXT_CREATING;
-		ret = vfs_get_tree(fc);
-		if (ret)
-			break;
-		sb = fc->root->d_sb;
-		ret = security_sb_kern_mount(sb);
-		if (unlikely(ret)) {
-			fc_drop_locked(fc);
-			break;
-		}
-		up_write(&sb->s_umount);
-		fc->phase = FS_CONTEXT_AWAITING_MOUNT;
-		return 0;
+		return vfs_cmd_create(fc, false);
+	case FSCONFIG_CMD_CREATE_EXCL:
+		return vfs_cmd_create(fc, true);
 	case FSCONFIG_CMD_RECONFIGURE:
-		if (fc->phase != FS_CONTEXT_RECONF_PARAMS)
-			return -EBUSY;
-		fc->phase = FS_CONTEXT_RECONFIGURING;
-		sb = fc->root->d_sb;
-		if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) {
-			ret = -EPERM;
-			break;
-		}
-		down_write(&sb->s_umount);
-		ret = reconfigure_super(fc);
-		up_write(&sb->s_umount);
-		if (ret)
-			break;
-		vfs_clean_context(fc);
-		return 0;
+		return vfs_cmd_reconfigure(fc);
 	default:
 		if (fc->phase != FS_CONTEXT_CREATE_PARAMS &&
 		    fc->phase != FS_CONTEXT_RECONF_PARAMS)
@@ -264,8 +301,6 @@ static int vfs_fsconfig_locked(struct fs_context *fc, int cmd,
 
 		return vfs_parse_fs_param(fc, param);
 	}
-	fc->phase = FS_CONTEXT_FAILED;
-	return ret;
 }
 
 /**
@@ -353,6 +388,7 @@ SYSCALL_DEFINE5(fsconfig,
 			return -EINVAL;
 		break;
 	case FSCONFIG_CMD_CREATE:
+	case FSCONFIG_CMD_CREATE_EXCL:
 	case FSCONFIG_CMD_RECONFIGURE:
 		if (_key || _value || aux)
 			return -EINVAL;