Btrfs: Remove extent back refs in batches, and avoid duplicate searches (952fccac) · Commits · e / devices / android_kernel_xiaomi_markw

fs/btrfs/extent-tree.c

+54 −9

Original line number	Diff line number	Diff line
		@@ -1251,6 +1251,9 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
		struct btrfs_root *extent_root = info->extent_root;
		struct extent_buffer *leaf;
		int ret;
		int extent_slot = 0;
		int found_extent = 0;
		int num_to_del = 1;
		struct btrfs_extent_item *ei;
		u32 refs;

		@@ -1267,6 +1270,23 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
		ref_generation,
		owner_objectid, owner_offset, 1);
		if (ret == 0) {
		struct btrfs_key found_key;
		extent_slot = path->slots[0];
		while(extent_slot > 0) {
		extent_slot--;
		btrfs_item_key_to_cpu(path->nodes[0], &found_key,
		extent_slot);
		if (found_key.objectid != bytenr)
		break;
		if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
		found_key.offset == num_bytes) {
		found_extent = 1;
		break;
		}
		if (path->slots[0] - extent_slot > 5)
		break;
		}
		if (!found_extent)
		ret = btrfs_del_item(trans, extent_root, path);
		} else {
		btrfs_print_leaf(extent_root, path->nodes[0]);
		@@ -1276,21 +1296,46 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
		root_objectid, ref_generation, owner_objectid,
		owner_offset);
		}
		if (!found_extent) {
		btrfs_release_path(extent_root, path);
		ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
		if (ret < 0)
		return ret;
		BUG_ON(ret);
		extent_slot = path->slots[0];
		}

		leaf = path->nodes[0];
		ei = btrfs_item_ptr(leaf, path->slots[0],
		ei = btrfs_item_ptr(leaf, extent_slot,
		struct btrfs_extent_item);
		refs = btrfs_extent_refs(leaf, ei);
		BUG_ON(refs == 0);
		refs -= 1;
		btrfs_set_extent_refs(leaf, ei, refs);

		btrfs_mark_buffer_dirty(leaf);

		if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
		/* if the back ref and the extent are next to each other
		* they get deleted below in one shot
		*/
		path->slots[0] = extent_slot;
		num_to_del = 2;
		} else if (found_extent) {
		/* otherwise delete the extent back ref */
		ret = btrfs_del_item(trans, extent_root, path);
		BUG_ON(ret);
		/* if refs are 0, we need to setup the path for deletion */
		if (refs == 0) {
		btrfs_release_path(extent_root, path);
		ret = btrfs_search_slot(trans, extent_root, &key, path,
		-1, 1);
		if (ret < 0)
		return ret;
		BUG_ON(ret);
		}
		}

		if (refs == 0) {
		u64 super_used;
		u64 root_used;
		@@ -1311,8 +1356,8 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
		root_used = btrfs_root_used(&root->root_item);
		btrfs_set_root_used(&root->root_item,
		root_used - num_bytes);

		ret = btrfs_del_item(trans, extent_root, path);
		ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
		num_to_del);
		if (ret) {
		return ret;
		}