Re: [PATCH 0/2] btrfs: qgroup: mark qgroup inconsistent for more

[Boris Burkov <boris@bur.io>]

On Thu, Aug 27, 2026 at 04:25:28PM +0930, Qu Wenruo wrote:
> Commit 011b46c30476 ("btrfs: skip subtree scan if it's too high to avoid
> low stall in btrfs_commit_transaction()") covers the most common case
> that can cause a long qgroup stall, where a large subtree is rescanned
> when dropping a snapshot.
> 
> But there are more corner cases for the same long qgroup stall:
> 
> - A qgroup rescan is queued immediately after marking inconsistent
>   The new rescan will immediately revert the NO_ACCOUNTING flag, thus
>   still results long qgroup stalls.
> 
> - A subvolume with no shared subtree
>   This can still queue a lot of workload into the current transaction.
> 
> This series covers both less-common cases.

Reviewed-by: Boris Burkov <boris@bur.io>

Thanks,
Boris

> 
> Qu Wenruo (2):
>   btrfs: reject new qgroup rescan during subvolume dropping
>   btrfs: avoid long stall when dropping a non-shared large subvolume
> 
>  fs/btrfs/disk-io.c     |  4 ++++
>  fs/btrfs/extent-tree.c | 11 +++++++++++
>  fs/btrfs/qgroup.c      | 29 ++++++++++++++++++++++++++++-
>  fs/btrfs/qgroup.h      | 15 +++++++++++++++
>  4 files changed, 58 insertions(+), 1 deletion(-)
> 
> -- 
> 2.55.0
>