Commit a1897fdd authored by Liu Bo's avatar Liu Bo Committed by Josef Bacik
Browse files

Btrfs: record first logical byte in memory 



This'd save us a rbtree search which may become expensive in large filesystem.

Signed-off-by: default avatarLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: default avatarJosef Bacik <jbacik@fusionio.com>
parent 39f9d028

fs/btrfs/ctree.h

+1 −0
Original line number Diff line number Diff line
@@ -1250,6 +1250,7 @@ struct btrfs_fs_info { 


	/* block group cache stuff */

	spinlock_t block_group_cache_lock;

	u64 first_logical_byte;

	struct rb_root block_group_cache_tree;



	/* keep track of unallocated space */

fs/btrfs/disk-io.c

+1 −0
Original line number Diff line number Diff line
@@ -2130,6 +2130,7 @@ int open_ctree(struct super_block *sb, 


	spin_lock_init(&fs_info->block_group_cache_lock);

	fs_info->block_group_cache_tree = RB_ROOT;

	fs_info->first_logical_byte = (u64)-1;



	extent_io_tree_init(&fs_info->freed_extents[0],

			     fs_info->btree_inode->i_mapping);

fs/btrfs/extent-tree.c

+18 −1
Original line number Diff line number Diff line
@@ -161,6 +161,10 @@ static int btrfs_add_block_group_cache(struct btrfs_fs_info *info, 
	rb_link_node(&block_group->cache_node, parent, p);

	rb_insert_color(&block_group->cache_node,

			&info->block_group_cache_tree);



	if (info->first_logical_byte > block_group->key.objectid)

		info->first_logical_byte = block_group->key.objectid;



	spin_unlock(&info->block_group_cache_lock);



	return 0;
@@ -202,8 +206,11 @@ block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr, 
			break;

		}

	}

	if (ret)

	if (ret) {

		btrfs_get_block_group(ret);

		if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)

			info->first_logical_byte = ret->key.objectid;

	}

	spin_unlock(&info->block_group_cache_lock);



	return ret;
@@ -4848,6 +4855,13 @@ static u64 first_logical_byte(struct btrfs_root *root, u64 search_start) 
	struct btrfs_block_group_cache *cache;

	u64 bytenr;



	spin_lock(&root->fs_info->block_group_cache_lock);

	bytenr = root->fs_info->first_logical_byte;

	spin_unlock(&root->fs_info->block_group_cache_lock);



	if (bytenr < (u64)-1)

		return bytenr;



	cache = btrfs_lookup_first_block_group(root->fs_info, search_start);

	if (!cache)

		return 0;
@@ -8059,6 +8073,9 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, 
	spin_lock(&root->fs_info->block_group_cache_lock);

	rb_erase(&block_group->cache_node,

		 &root->fs_info->block_group_cache_tree);



	if (root->fs_info->first_logical_byte == block_group->key.objectid)

		root->fs_info->first_logical_byte = (u64)-1;

	spin_unlock(&root->fs_info->block_group_cache_lock);



	down_write(&block_group->space_info->groups_sem);