Since reloc tree doesn't contribute to qgroup numbers, just skip them.
This should catch the final cause of unnecessary data refs for qgroup +
metadata balance.
The 4G data 16 snapshots test (*) should explain it pretty well:
| delayed subtree | refactor delayed ref | this patch
---------------------------------------------------------------------
relocated | 22653 | 22673 | 22744
qgroup dirty | 122792 | 48360 | 70
time | 24.494 | 11.606 | 3.944
Finally, we're at the stage where qgroup + metadata balance cost no
obvious overhead.
*: Test environment
Test VM:
- vRAM 8G
- vCPU 8
- block dev vitrio-blk, 'unsafe' cache mode
- host block 850evo
Test workload
- Copy 4G data from /usr/ to one subvolume
- Create 16 snapshots of that subvolume, and modify 3 files in each
snapshot
- Enable quota, rescan
- Time "btrfs balance start -m"
Signed-off-by: Qu Wenruo <w...@suse.com>
---
fs/btrfs/extent-tree.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 2c08b9646c61..2d71cc1acb2f 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -9235,11 +9235,13 @@ static noinline int walk_up_proc(struct
btrfs_trans_handle *trans,
else
ret = btrfs_dec_ref(trans, root, eb, 0);
BUG_ON(ret); /* -ENOMEM */
- ret = btrfs_qgroup_trace_leaf_items(trans, eb);
- if (ret) {
- btrfs_err_rl(fs_info,
- "error %d accounting leaf items.
Quota is out of sync, rescan required.",
+ if (is_fstree(root->root_key.objectid)) {
+ ret = btrfs_qgroup_trace_leaf_items(trans, eb);
+ if (ret) {
+ btrfs_err_rl(fs_info,
+"error %d accounting leaf items. Quota is out of sync, rescan required.",
ret);
+ }
}
}
/* make block locked assertion in btrfs_clean_tree_block happy
*/
--
2.21.0
