[PATCH 7/8] Btrfs: record first logical byte in memory
From: Liu Bo <hidden>
Date: 2012-12-27 09:04:02
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Chris Mason, David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
This'd save us a rbtree search which may become expensive in large filesystem. Signed-off-by: Liu Bo <redacted> --- fs/btrfs/ctree.h | 1 + fs/btrfs/disk-io.c | 1 + fs/btrfs/extent-tree.c | 19 ++++++++++++++++++- 3 files changed, 20 insertions(+), 1 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index d709c4d..c2f24a0 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h@@ -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 */
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index a8f652d..456b80f 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c@@ -2126,6 +2126,7 @@ 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);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 7a87e19..60d5081 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c@@ -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;
@@ -4815,6 +4822,13 @@ 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;
@@ -8024,6 +8038,9 @@ 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);
--
1.7.7.6