Commit 56e9357a authored by David Sterba's avatar David Sterba
Browse files

btrfs: simplify root lookup by id 



The main function to lookup a root by its id btrfs_get_fs_root takes the
whole key, while only using the objectid. The value of offset is preset
to (u64)-1 but not actually used until btrfs_find_root that does the
actual search.

Switch btrfs_get_fs_root to use only objectid and remove all local
variables that existed just for the lookup. The actual key for search is
set up in btrfs_get_fs_root, reusing another key variable.

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 1dae7e0e

fs/btrfs/backref.c

+2 −11
Original line number Diff line number Diff line
@@ -538,18 +538,13 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info, 
				const u64 *extent_item_pos, bool ignore_offset)

{

	struct btrfs_root *root;

	struct btrfs_key root_key;

	struct extent_buffer *eb;

	int ret = 0;

	int root_level;

	int level = ref->level;

	struct btrfs_key search_key = ref->key_for_search;



	root_key.objectid = ref->root_id;

	root_key.type = BTRFS_ROOT_ITEM_KEY;

	root_key.offset = (u64)-1;



	root = btrfs_get_fs_root(fs_info, &root_key, false);

	root = btrfs_get_fs_root(fs_info, ref->root_id, false);

	if (IS_ERR(root)) {

		ret = PTR_ERR(root);

		goto out_free;
@@ -2690,16 +2685,12 @@ static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache, 
	struct btrfs_backref_edge *edge;

	struct extent_buffer *eb;

	struct btrfs_root *root;

	struct btrfs_key root_key;

	struct rb_node *rb_node;

	int level;

	bool need_check = true;

	int ret;



	root_key.objectid = ref_key->offset;

	root_key.type = BTRFS_ROOT_ITEM_KEY;

	root_key.offset = (u64)-1;

	root = btrfs_get_fs_root(fs_info, &root_key, false);

	root = btrfs_get_fs_root(fs_info, ref_key->offset, false);

	if (IS_ERR(root))

		return PTR_ERR(root);

	if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))

fs/btrfs/disk-io.c

+18 −21
Original line number Diff line number Diff line
@@ -1534,35 +1534,34 @@ void btrfs_free_fs_info(struct btrfs_fs_info *fs_info) 




struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,

				     struct btrfs_key *location,

				     bool check_ref)

				     u64 objectid, bool check_ref)

{

	struct btrfs_root *root;

	struct btrfs_path *path;

	struct btrfs_key key;

	int ret;



	if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)

	if (objectid == BTRFS_ROOT_TREE_OBJECTID)

		return btrfs_grab_root(fs_info->tree_root);

	if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)

	if (objectid == BTRFS_EXTENT_TREE_OBJECTID)

		return btrfs_grab_root(fs_info->extent_root);

	if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)

	if (objectid == BTRFS_CHUNK_TREE_OBJECTID)

		return btrfs_grab_root(fs_info->chunk_root);

	if (location->objectid == BTRFS_DEV_TREE_OBJECTID)

	if (objectid == BTRFS_DEV_TREE_OBJECTID)

		return btrfs_grab_root(fs_info->dev_root);

	if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)

	if (objectid == BTRFS_CSUM_TREE_OBJECTID)

		return btrfs_grab_root(fs_info->csum_root);

	if (location->objectid == BTRFS_QUOTA_TREE_OBJECTID)

	if (objectid == BTRFS_QUOTA_TREE_OBJECTID)

		return btrfs_grab_root(fs_info->quota_root) ?

			fs_info->quota_root : ERR_PTR(-ENOENT);

	if (location->objectid == BTRFS_UUID_TREE_OBJECTID)

	if (objectid == BTRFS_UUID_TREE_OBJECTID)

		return btrfs_grab_root(fs_info->uuid_root) ?

			fs_info->uuid_root : ERR_PTR(-ENOENT);

	if (location->objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)

	if (objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)

		return btrfs_grab_root(fs_info->free_space_root) ?

			fs_info->free_space_root : ERR_PTR(-ENOENT);

again:

	root = btrfs_lookup_fs_root(fs_info, location->objectid);

	root = btrfs_lookup_fs_root(fs_info, objectid);

	if (root) {

		if (check_ref && btrfs_root_refs(&root->root_item) == 0) {

			btrfs_put_root(root);
@@ -1571,7 +1570,10 @@ struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info, 
		return root;

	}



	root = btrfs_read_tree_root(fs_info->tree_root, location);

	key.objectid = objectid;

	key.type = BTRFS_ROOT_ITEM_KEY;

	key.offset = (u64)-1;

	root = btrfs_read_tree_root(fs_info->tree_root, &key);

	if (IS_ERR(root))

		return root;
@@ -1591,7 +1593,7 @@ struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info, 
	}

	key.objectid = BTRFS_ORPHAN_OBJECTID;

	key.type = BTRFS_ORPHAN_ITEM_KEY;

	key.offset = location->objectid;

	key.offset = objectid;



	ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);

	btrfs_free_path(path);
@@ -2293,8 +2295,8 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info) 
	 * This tree can share blocks with some other fs tree during relocation

	 * and we need a proper setup by btrfs_get_fs_root

	 */

	location.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;

	root = btrfs_get_fs_root(tree_root->fs_info, &location, true);

	root = btrfs_get_fs_root(tree_root->fs_info,

				 BTRFS_DATA_RELOC_TREE_OBJECTID, true);

	if (IS_ERR(root)) {

		ret = PTR_ERR(root);

		goto out;
@@ -2839,7 +2841,6 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device 
	u64 generation;

	u64 features;

	u16 csum_type;

	struct btrfs_key location;

	struct btrfs_super_block *disk_super;

	struct btrfs_fs_info *fs_info = btrfs_sb(sb);

	struct btrfs_root *tree_root;
@@ -3253,11 +3254,7 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device 
		}

	}



	location.objectid = BTRFS_FS_TREE_OBJECTID;

	location.type = BTRFS_ROOT_ITEM_KEY;

	location.offset = 0;



	fs_info->fs_root = btrfs_get_fs_root(fs_info, &location, true);

	fs_info->fs_root = btrfs_get_fs_root(fs_info, BTRFS_FS_TREE_OBJECTID, true);

	if (IS_ERR(fs_info->fs_root)) {

		err = PTR_ERR(fs_info->fs_root);

		btrfs_warn(fs_info, "failed to read fs tree: %d", err);

fs/btrfs/disk-io.h

+1 −2
Original line number Diff line number Diff line
@@ -66,8 +66,7 @@ int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info, 
void btrfs_free_fs_roots(struct btrfs_fs_info *fs_info);



struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,

				     struct btrfs_key *key,

				     bool check_ref);

				     u64 objectid, bool check_ref);



void btrfs_free_fs_info(struct btrfs_fs_info *fs_info);

int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info);

fs/btrfs/export.c

+1 −5
Original line number Diff line number Diff line
@@ -69,11 +69,7 @@ struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid, 
	if (objectid < BTRFS_FIRST_FREE_OBJECTID)

		return ERR_PTR(-ESTALE);



	key.objectid = root_objectid;

	key.type = BTRFS_ROOT_ITEM_KEY;

	key.offset = (u64)-1;



	root = btrfs_get_fs_root(fs_info, &key, true);

	root = btrfs_get_fs_root(fs_info, root_objectid, true);

	if (IS_ERR(root))

		return ERR_CAST(root);

fs/btrfs/file.c

+1 −5
Original line number Diff line number Diff line
@@ -281,11 +281,7 @@ static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info, 
	int ret;



	/* get the inode */

	key.objectid = defrag->root;

	key.type = BTRFS_ROOT_ITEM_KEY;

	key.offset = (u64)-1;



	inode_root = btrfs_get_fs_root(fs_info, &key, true);

	inode_root = btrfs_get_fs_root(fs_info, defrag->root, true);

	if (IS_ERR(inode_root)) {

		ret = PTR_ERR(inode_root);

		goto cleanup;