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Btrfs: record first logical byte in memory 

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

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
This commit is contained in:
Liu Bo 2012-12-27 09:01:23 +00:00 committed by Josef Bacik
parent 39f9d028c9
commit a1897fddd2
3 changed files with 20 additions and 1 deletions
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1
fs/btrfs/ctree.h
View File

@ -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 */

1
fs/btrfs/disk-io.c
View File

@ -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);

19
fs/btrfs/extent-tree.c
View File

@ -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);