kevin/linux
1
Fork 0
Code

btrfs: avoid unnecessary ref initialization when freeing log tree block

Browse Source 
At btrfs_free_tree_block(), we are always initializing a delayed reference
to drop the given extent buffer but we only use if it does not belong to a
log root tree. So we are doing unnecessary work here and increasing the
duration of a critical section as this is normally called while holding a
lock on the parent tree block (if any) and while holding a log transaction
open.

So initialize the delayed reference only if the extent buffer is not from
a log tree, avoiding unnecessary work and making the code also a bit
easier to follow.

Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Filipe Manana 2024-02-19 12:51:25 +00:00 committed by David Sterba
parent 0e9e135e7c
commit 74cd8cac0b
1 changed files with 7 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
fs/btrfs/extent-tree.c
View File

@ -3458,16 +3458,17 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
u64 parent, int last_ref)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_ref generic_ref = { 0 };
struct btrfs_block_group *bg;
int ret;
btrfs_init_generic_ref(&generic_ref, BTRFS_DROP_DELAYED_REF,
buf->start, buf->len, parent, btrfs_header_owner(buf));
btrfs_init_tree_ref(&generic_ref, btrfs_header_level(buf),
root_id, 0, false);
if (root_id != BTRFS_TREE_LOG_OBJECTID) {
struct btrfs_ref generic_ref = { 0 };
btrfs_init_generic_ref(&generic_ref, BTRFS_DROP_DELAYED_REF,
buf->start, buf->len, parent,
btrfs_header_owner(buf));
btrfs_init_tree_ref(&generic_ref, btrfs_header_level(buf),
root_id, 0, false);
btrfs_ref_tree_mod(fs_info, &generic_ref);
ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, NULL);
BUG_ON(ret); /* -ENOMEM */