Commit 9ba7c686 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: do not utilize goto to implement delayed inode ref deletion 



[PROBLEM]
The function __btrfs_update_delayed_inode() is doing something not
meeting the code standard of today:

	path->slots[0]++
	if (path->slots[0] >= btrfs_header_nritems(leaf))
		goto search;
again:
	if (!is_the_target_inode_ref())
		goto out;
	ret = btrfs_delete_item();
	/* Some cleanup. */
	return ret;

search:
	ret = search_for_the_last_inode_ref();
	goto again;

With the tag named "again", it's pretty common to think it's a loop, but
the truth is, we only need to do the search once, to locate the last
(also the first, since there should only be one INODE_REF or
INODE_EXTREF now) ref of the inode.

[FIX]
Instead of the weird jumps, just do them in a stream-lined fashion.
This removes those weird labels, and add extra comments on why we can do
the different searches.

Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 80d197fe

fs/btrfs/delayed-inode.c

+24 −21
Original line number Diff line number Diff line
@@ -1036,14 +1036,33 @@ static int __btrfs_update_delayed_inode(struct btrfs_trans_handle *trans, 
	if (!test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &node->flags))

		goto out;



	/*

	 * Now we're going to delete the INODE_REF/EXTREF, which should be the

	 * only one ref left.  Check if the next item is an INODE_REF/EXTREF.

	 *

	 * But if we're the last item already, release and search for the last

	 * INODE_REF/EXTREF.

	 */

	if (path->slots[0] + 1 >= btrfs_header_nritems(leaf)) {

		key.objectid = node->inode_id;

		key.type = BTRFS_INODE_EXTREF_KEY;

		key.offset = (u64)-1;



		btrfs_release_path(path);

		ret = btrfs_search_slot(trans, root, &key, path, -1, 1);

		if (ret < 0)

			goto err_out;

		ASSERT(ret > 0);

		ASSERT(path->slots[0] > 0);

		ret = 0;

		path->slots[0]--;

		leaf = path->nodes[0];

	} else {

		path->slots[0]++;

	if (path->slots[0] >= btrfs_header_nritems(leaf))

		goto search;

again:

	}

	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);

	if (key.objectid != node->inode_id)

		goto out;



	if (key.type != BTRFS_INODE_REF_KEY &&

	    key.type != BTRFS_INODE_EXTREF_KEY)

		goto out;
@@ -1070,22 +1089,6 @@ static int __btrfs_update_delayed_inode(struct btrfs_trans_handle *trans, 
		btrfs_abort_transaction(trans, ret);



	return ret;



search:

	btrfs_release_path(path);



	key.type = BTRFS_INODE_EXTREF_KEY;

	key.offset = -1;



	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);

	if (ret < 0)

		goto err_out;

	ASSERT(ret);



	ret = 0;

	leaf = path->nodes[0];

	path->slots[0]--;

	goto again;

}



static inline int btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,