Re: [PATCH] btrfs: fix leak of qgroup extent records after transaction abort

[Josef Bacik <josef@toxicpanda.com>]

On Mon, Jun 03, 2024 at 01:06:13PM +0100, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> Qgroup extent records are created when delayed ref heads are created and
> then released after accounting extents at btrfs_qgroup_account_extents(),
> called during the transaction commit path.
> 
> If a transaction is aborted we free the qgroup records by calling
> btrfs_qgroup_destroy_extent_records() at btrfs_destroy_delayed_refs(),
> unless we don't have delayed references. We are incorrectly assuming
> that no delayed references means we don't have qgroup extents records.
> 
> We can currently have no delayed references because we ran them all
> during a transaction commit and the transaction was aborted after that
> due to some error in the commit path.
> 
> So fix this by ensuring we btrfs_qgroup_destroy_extent_records() at
> btrfs_destroy_delayed_refs() even if we don't have any delayed references.
> 
> Reported-by: syzbot+0fecc032fa134afd49df@syzkaller.appspotmail.com
> Link: https://lore.kernel.org/linux-btrfs/0000000000004e7f980619f91835@google.com/
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef