d_add_ci() should just accept a hashed exact match if it finds one

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

fs/dcache.c

@@ -1888,51 +1888,19 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
 	 * if not go ahead and create it now.
 	 */
 	found = d_hash_and_lookup(dentry->d_parent, name);
-	if (unlikely(IS_ERR(found)))
-		goto err_out;
 	if (!found) {
 		new = d_alloc(dentry->d_parent, name);
 		if (!new) {
 			found = ERR_PTR(-ENOMEM);
-			goto err_out;
-		}
-
-		found = d_splice_alias(inode, new);
-		if (found) {
-			dput(new);
-			return found;
-		}
-		return new;
-	}
-
-	/*
-	 * If a matching dentry exists, and it's not negative use it.
-	 *
-	 * Decrement the reference count to balance the iget() done
-	 * earlier on.
-	 */
-	if (found->d_inode) {
-		if (unlikely(found->d_inode != inode)) {
-			/* This can't happen because bad inodes are unhashed. */
-			BUG_ON(!is_bad_inode(inode));
-			BUG_ON(!is_bad_inode(found->d_inode));
+		} else {
+			found = d_splice_alias(inode, new);
+			if (found) {
+				dput(new);
+				return found;
+			}
+			return new;
 		}
-		iput(inode);
-		return found;
 	}
-
-	/*
-	 * Negative dentry: instantiate it unless the inode is a directory and
-	 * already has a dentry.
-	 */
-	new = d_splice_alias(inode, found);
-	if (new) {
-		dput(found);
-		found = new;
-	}
-	return found;
-
-err_out:
 	iput(inode);
 	return found;
 }