Revert "ovl: fix may_write_real() for overlayfs directories"

This reverts commit 954c736f.

Overlayfs no longer relies on the vfs for checking writability of files.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/namespace.c

@@ -468,9 +468,7 @@ static inline int may_write_real(struct file *file)
 
 	/* File refers to upper, writable layer? */
 	upperdentry = d_real(dentry, NULL, 0, D_REAL_UPPER);
-	if (upperdentry &&
-	    (file_inode(file) == d_inode(upperdentry) ||
-	     file_inode(file) == d_inode(dentry)))
+	if (upperdentry && file_inode(file) == d_inode(upperdentry))
 		return 0;
 
 	/* Lower layer: can't write to real file, sorry... */