btrfs: reloc: refactor direct tree backref processing into its own function (4007ea87) · Commits · 戴 / test

fs/btrfs/relocation.c

+78 −52

Original line number	Diff line number	Diff line
		@@ -698,6 +698,81 @@ static struct btrfs_root read_fs_root(struct btrfs_fs_info fs_info,
		return btrfs_get_fs_root(fs_info, &key, false);
		}

		/*
		* Handle direct tree backref
		*
		* Direct tree backref means, the backref item shows its parent bytenr
		* directly. This is for SHARED_BLOCK_REF backref (keyed or inlined).
		*
		* @ref_key: The converted backref key.
		* For keyed backref, it's the item key.
		* For inlined backref, objectid is the bytenr,
		* type is btrfs_inline_ref_type, offset is
		* btrfs_inline_ref_offset.
		*/
		static int handle_direct_tree_backref(struct backref_cache *cache,
		struct btrfs_key *ref_key,
		struct backref_node *cur)
		{
		struct backref_edge *edge;
		struct backref_node *upper;
		struct rb_node *rb_node;

		ASSERT(ref_key->type == BTRFS_SHARED_BLOCK_REF_KEY);

		/* Only reloc root uses backref pointing to itself */
		if (ref_key->objectid == ref_key->offset) {
		struct btrfs_root *root;

		cur->is_reloc_root = 1;
		/* Only reloc backref cache cares about a specific root */
		if (cache->is_reloc) {
		root = find_reloc_root(cache->fs_info, cur->bytenr);
		if (WARN_ON(!root))
		return -ENOENT;
		cur->root = root;
		} else {
		/*
		* For generic purpose backref cache, reloc root node
		* is useless.
		*/
		list_add(&cur->list, &cache->useless_node);
		}
		return 0;
		}

		edge = alloc_backref_edge(cache);
		if (!edge)
		return -ENOMEM;

		rb_node = tree_search(&cache->rb_root, ref_key->offset);
		if (!rb_node) {
		/* Parent node not yet cached */
		upper = alloc_backref_node(cache);
		if (!upper) {
		free_backref_edge(cache, edge);
		return -ENOMEM;
		}
		upper->bytenr = ref_key->offset;
		upper->level = cur->level + 1;

		/*
		* Backrefs for the upper level block isn't cached, add the
		* block to pending list
		*/
		list_add_tail(&edge->list[UPPER], &cache->pending_edge);
		} else {
		/* Parent node already cached */
		upper = rb_entry(rb_node, struct backref_node, rb_node);
		ASSERT(upper->checked);
		INIT_LIST_HEAD(&edge->list[UPPER]);
		}
		list_add_tail(&edge->list[LOWER], &cur->upper);
		edge->node[LOWER] = cur;
		edge->node[UPPER] = upper;
		return 0;
		}

		/*
		* build backref tree for a given tree block. root of the backref tree
		* corresponds the tree block, leaves of the backref tree correspond
		@@ -719,7 +794,6 @@ struct backref_node build_backref_tree(struct reloc_control rc,
		{
		struct btrfs_backref_iter *iter;
		struct backref_cache *cache = &rc->backref_cache;
		struct btrfs_fs_info *fs_info = cache->fs_info;
		/* For searching parent of TREE_BLOCK_REF */
		struct btrfs_path *path;
		struct btrfs_root *root;
		@@ -841,59 +915,11 @@ again:

		/* SHARED_BLOCK_REF means key.offset is the parent bytenr */
		if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
		if (key.objectid == key.offset) {
		cur->is_reloc_root = 1;
		/* Only reloc backref cache cares exact root */
		if (cache->is_reloc) {
		root = find_reloc_root(fs_info,
		cur->bytenr);
		if (WARN_ON(!root)) {
		err = -ENOENT;
		goto out;
		}
		cur->root = root;
		} else {
		/*
		* For generic purpose backref cache,
		* reloc root node is useless.
		*/
		list_add(&cur->list,
		&cache->useless_node);
		}
		break;
		}

		edge = alloc_backref_edge(cache);
		if (!edge) {
		err = -ENOMEM;
		goto out;
		}
		rb_node = tree_search(&cache->rb_root, key.offset);
		if (!rb_node) {
		upper = alloc_backref_node(cache);
		if (!upper) {
		free_backref_edge(cache, edge);
		err = -ENOMEM;
		ret = handle_direct_tree_backref(cache, &key, cur);
		if (ret < 0) {
		err = ret;
		goto out;
		}
		upper->bytenr = key.offset;
		upper->level = cur->level + 1;
		/*
		* backrefs for the upper level block isn't
		* cached, add the block to pending list
		*/
		list_add_tail(&edge->list[UPPER],
		&cache->pending_edge);
		} else {
		upper = rb_entry(rb_node, struct backref_node,
		rb_node);
		ASSERT(upper->checked);
		INIT_LIST_HEAD(&edge->list[UPPER]);
		}
		list_add_tail(&edge->list[LOWER], &cur->upper);
		edge->node[LOWER] = cur;
		edge->node[UPPER] = upper;

		continue;
		} else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
		err = -EINVAL;

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