ovl: create helper ovl_create_temp()

Also used ovl_create_temp() in ovl_create_index() instead of calling
ovl_do_mkdir() directly, so now all callers of ovl_do_mkdir() are routed
through ovl_create_real(), which paves the way for Al's fix for non-hashed
result from vfs_mkdir().

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/overlayfs.h

@@ -346,7 +346,6 @@ static inline void ovl_copyattr(struct inode *from, struct inode *to)
 
 /* dir.c */
 extern const struct inode_operations ovl_dir_inode_operations;
-struct dentry *ovl_lookup_temp(struct dentry *workdir);
 int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir,
 			     struct dentry *dentry);
 struct ovl_cattr {
@@ -361,6 +360,7 @@ struct ovl_cattr {
 struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
 			       struct ovl_cattr *attr);
 int ovl_cleanup(struct inode *dir, struct dentry *dentry);
+struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr);
 
 /* copy_up.c */
 int ovl_copy_up(struct dentry *dentry);