Commit e3ba67a1 authored by Johannes Thumshirn's avatar Johannes Thumshirn Committed by David Sterba
Browse files

btrfs: factor out reading of bg from find_frist_block_group 



When find_first_block_group() finds a block group item in the extent-tree,
it does a lookup of the object in the extent mapping tree and does further
checks on the item.

Factor out this step from find_first_block_group() so we can further
simplify the code.

While we're at it, we can also just return early in
find_first_block_group(), if the tree slot isn't found.

Signed-off-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 89d7da9b

fs/btrfs/block-group.c

+56 −46
Original line number Diff line number Diff line
@@ -1532,21 +1532,70 @@ void btrfs_mark_bg_unused(struct btrfs_block_group *bg) 
	spin_unlock(&fs_info->unused_bgs_lock);

}



static int read_bg_from_eb(struct btrfs_fs_info *fs_info, struct btrfs_key *key,

			   struct btrfs_path *path)

{

	struct extent_map_tree *em_tree;

	struct extent_map *em;

	struct btrfs_block_group_item bg;

	struct extent_buffer *leaf;

	int slot;

	u64 flags;

	int ret = 0;



	slot = path->slots[0];

	leaf = path->nodes[0];



	em_tree = &fs_info->mapping_tree;

	read_lock(&em_tree->lock);

	em = lookup_extent_mapping(em_tree, key->objectid, key->offset);

	read_unlock(&em_tree->lock);

	if (!em) {

		btrfs_err(fs_info,

			  "logical %llu len %llu found bg but no related chunk",

			  key->objectid, key->offset);

		return -ENOENT;

	}



	if (em->start != key->objectid || em->len != key->offset) {

		btrfs_err(fs_info,

			"block group %llu len %llu mismatch with chunk %llu len %llu",

			key->objectid, key->offset, em->start, em->len);

		ret = -EUCLEAN;

		goto out_free_em;

	}



	read_extent_buffer(leaf, &bg, btrfs_item_ptr_offset(leaf, slot),

			   sizeof(bg));

	flags = btrfs_stack_block_group_flags(&bg) &

		BTRFS_BLOCK_GROUP_TYPE_MASK;



	if (flags != (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {

		btrfs_err(fs_info,

"block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",

			  key->objectid, key->offset, flags,

			  (BTRFS_BLOCK_GROUP_TYPE_MASK & em->map_lookup->type));

		ret = -EUCLEAN;

	}



out_free_em:

	free_extent_map(em);

	return ret;

}



static int find_first_block_group(struct btrfs_fs_info *fs_info,

				  struct btrfs_path *path,

				  struct btrfs_key *key)

{

	struct btrfs_root *root = fs_info->extent_root;

	int ret = 0;

	int ret;

	struct btrfs_key found_key;

	struct extent_buffer *leaf;

	struct btrfs_block_group_item bg;

	u64 flags;

	int slot;



	ret = btrfs_search_slot(NULL, root, key, path, 0, 0);

	if (ret < 0)

		goto out;

		return ret;



	while (1) {

		slot = path->slots[0];
@@ -1563,49 +1612,10 @@ static int find_first_block_group(struct btrfs_fs_info *fs_info, 


		if (found_key.objectid >= key->objectid &&

		    found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {

			struct extent_map_tree *em_tree;

			struct extent_map *em;



			em_tree = &fs_info->mapping_tree;

			read_lock(&em_tree->lock);

			em = lookup_extent_mapping(em_tree, found_key.objectid,

						   found_key.offset);

			read_unlock(&em_tree->lock);

			if (!em) {

				btrfs_err(fs_info,

			"logical %llu len %llu found bg but no related chunk",

					  found_key.objectid, found_key.offset);

				ret = -ENOENT;

			} else if (em->start != found_key.objectid ||

				   em->len != found_key.offset) {

				btrfs_err(fs_info,

		"block group %llu len %llu mismatch with chunk %llu len %llu",

					  found_key.objectid, found_key.offset,

					  em->start, em->len);

				ret = -EUCLEAN;

			} else {

				read_extent_buffer(leaf, &bg,

					btrfs_item_ptr_offset(leaf, slot),

					sizeof(bg));

				flags = btrfs_stack_block_group_flags(&bg) &

					BTRFS_BLOCK_GROUP_TYPE_MASK;



				if (flags != (em->map_lookup->type &

					      BTRFS_BLOCK_GROUP_TYPE_MASK)) {

					btrfs_err(fs_info,

"block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",

						found_key.objectid,

						found_key.offset, flags,

						(BTRFS_BLOCK_GROUP_TYPE_MASK &

						 em->map_lookup->type));

					ret = -EUCLEAN;

				} else {

					ret = 0;

				}

			}

			free_extent_map(em);

			goto out;

			ret = read_bg_from_eb(fs_info, &found_key, path);

			break;

		}



		path->slots[0]++;

	}

out: