btrfs: remove redundant name and name_len parameters to create_subvol

The passed dentry already contains the name.
Reviewed-by: NSweet Tea Dorminy <sweettea-kernel@dorminy.me>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/ioctl.c

@@ -546,9 +546,10 @@ int __pure btrfs_is_empty_uuid(u8 *uuid)
 
 static noinline int create_subvol(struct user_namespace *mnt_userns,
 				  struct inode *dir, struct dentry *dentry,
-				  const char *name, int namelen,
 				  struct btrfs_qgroup_inherit *inherit)
 {
+	const char *name = dentry->d_name.name;
+	int namelen = dentry->d_name.len;
 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 	struct btrfs_trans_handle *trans;
 	struct btrfs_key key;
@@ -980,7 +981,7 @@ static noinline int btrfs_mksubvol(const struct path *parent,
 	if (snap_src)
 		error = create_snapshot(snap_src, dir, dentry, readonly, inherit);
 	else
-		error = create_subvol(mnt_userns, dir, dentry, name, namelen, inherit);
+		error = create_subvol(mnt_userns, dir, dentry, inherit);
 
 	if (!error)
 		fsnotify_mkdir(dir, dentry);