Btrfs: Remove special cases for "." and ".."

Date: Sun, 17 Aug 2008 15:14:48 +0100
We never get asked by the VFS to lookup either of them, and we can
handle the readdir() case a lot more simply, too.
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

fs/btrfs/inode.c

@@ -1702,42 +1702,9 @@ static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
 	struct btrfs_root *root = BTRFS_I(dir)->root;
 	int ret = 0;
 
-	if (namelen == 1 && strcmp(name, ".") == 0) {
-		location->objectid = dir->i_ino;
-		location->type = BTRFS_INODE_ITEM_KEY;
-		location->offset = 0;
-		return 0;
-	}
 	path = btrfs_alloc_path();
 	BUG_ON(!path);
 
-	if (namelen == 2 && strcmp(name, "..") == 0) {
-		struct btrfs_key key;
-		struct extent_buffer *leaf;
-		int slot;
-
-		key.objectid = dir->i_ino;
-		key.offset = (u64)-1;
-		btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
-		if (ret < 0 || path->slots[0] == 0)
-			goto out_err;
-		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
-		BUG_ON(ret == 0);
-		ret = 0;
-		leaf = path->nodes[0];
-		slot = path->slots[0] - 1;
-
-		btrfs_item_key_to_cpu(leaf, &key, slot);
-		if (key.objectid != dir->i_ino ||
-		    key.type != BTRFS_INODE_REF_KEY) {
-			goto out_err;
-		}
-		location->objectid = key.offset;
-		location->type = BTRFS_INODE_ITEM_KEY;
-		location->offset = 0;
-		goto out;
-	}
-
 	di = btrfs_lookup_dir_item(NULL, root, path, dir->i_ino, name,
 				    namelen, 0);
 	if (IS_ERR(di))
@@ -1960,29 +1927,14 @@ static int btrfs_real_readdir(struct file *filp, void *dirent,
 
 	/* special case for .., just use the back ref */
 	if (filp->f_pos == 1) {
-		btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
-		key.offset = (u64)-1;
-		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
-		if (ret < 0 || path->slots[0] == 0) {
-			btrfs_release_path(root, path);
-			goto read_dir_items;
-		}
-		BUG_ON(ret == 0);
-		leaf = path->nodes[0];
-		slot = path->slots[0] - 1;
-		btrfs_item_key_to_cpu(leaf, &found_key, slot);
-		btrfs_release_path(root, path);
-		if (found_key.objectid != key.objectid ||
-		    found_key.type != BTRFS_INODE_REF_KEY)
-			goto read_dir_items;
+		u64 pino = parent_ino(filp->f_path.dentry);
 		over = filldir(dirent, "..", 2,
-			       2, found_key.offset, DT_DIR);
+			       2, pino, DT_DIR);
 		if (over)
 			goto nopos;
 		filp->f_pos = 2;
 	}
 
-read_dir_items:
 	btrfs_set_key_type(&key, key_type);
 	key.offset = filp->f_pos;