@@ -1915,6 +1915,33 @@ static int qgroup_update_counters(struct btrfs_fs_info *fs_info,
return 0;
}
+/*
+ * Helper to check if the @roots is a list of fs tree roots
+ * Return 0 for definitely not a fs/subvol tree roots ulist
+ * Return 1 for possible fs/subvol tree roots ulist(including empty)
+ */
+static int maybe_fs_roots(struct ulist *roots)
+{
+ struct ulist_node *unode;
+ struct ulist_iterator uiter;
+
+ /* Empty one, still possible for fs roots */
+ if (!roots || roots->nnodes == 0)
+ return 1;
+
+ ULIST_ITER_INIT(&uiter);
+ unode = ulist_next(roots, &uiter);
+ if (!unode)
+ return 1;
+
+ /*
+ * If it contains fs tree roots, then it must belongs to fs/subvol
+ * trees.
+ * If it contains non-fs tree, it won't be shared to fs/subvol trees.
+ */
+ return is_fstree(unode->val);
+}
+
int
btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
@@ -1931,10 +1958,20 @@ btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans,
if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
return 0;
- if (new_roots)
+ if (new_roots) {
+ if (!maybe_fs_roots(new_roots))
+ goto out_free;
nr_new_roots = new_roots->nnodes;
- if (old_roots)
+ }
+ if (old_roots) {
+ if (!maybe_fs_roots(old_roots))
+ goto out_free;
nr_old_roots = old_roots->nnodes;
+ }
+
+ /* Quick exit, either not fs tree roots, or won't affect any qgroup */
+ if (nr_old_roots == 0 && nr_new_roots == 0)
+ goto out_free;
BUG_ON(!fs_info->quota_root);
Modify btrfs_qgroup_account_extent() to exit quicker for non-fs extents. The quick exit condition is: 1) The extent belongs to a non-fs tree Only fs-tree extents can affect qgroup numbers and is the only case where extent can be shared between different trees. Although strictly speaking extent in data-reloc or tree-reloc tree can be shared, data/tree-reloc root won't occur in the result of btrfs_find_all_roots(), so we can ignore such corner case. So we can check the first root in old_roots/new_roots ulist. If we find the 1st root is a not a fs/subvol root, then we can skip the extent. If we find the 1st root is a fs/subvol root, then we must continue calculation. OR 2) both 'nr_old_roots' and 'nr_new_roots' are 0 This means either such extent get allocated then freed in current transaction or it's a new reloc tree extent, whose nr_new_roots is 0. Either way it won't affect qgroup accounting and can be skipped safely. Such quick exit can make trace output more quite and less confusing: (example with fs uuid and time stamp removed) Before: ------ add_delayed_tree_ref: bytenr=29556736 num_bytes=16384 action=ADD_DELAYED_REF parent=0(-) ref_root=2(EXTENT_TREE) level=0 type=TREE_BLOCK_REF seq=0 btrfs_qgroup_account_extent: bytenr=29556736 num_bytes=16384 nr_old_roots=0 nr_new_roots=1 ------ Extent tree block will trigger btrfs_qgroup_account_extent() trace point while no qgroup number is changed, as extent tree won't affect qgroup accounting. After: ------ add_delayed_tree_ref: bytenr=29556736 num_bytes=16384 action=ADD_DELAYED_REF parent=0(-) ref_root=2(EXTENT_TREE) level=0 type=TREE_BLOCK_REF seq=0 ------ Now such unrelated extent won't trigger btrfs_qgroup_account_extent() trace point, making the trace less noisy. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> --- fs/btrfs/qgroup.c | 41 +++++++++++++++++++++++++++++++++++++++-- 1 file changed, 39 insertions(+), 2 deletions(-)