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Date:   Wed, 16 Nov 2022 06:48:39 +0800
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Subject: Re: [PATCH v4 1/3] btrfs: add might_sleep() to some places in
 update_qgroup_limit_item()
Content-Language: en-US
To:     ChenXiaoSong <chenxiaosong2@huawei.com>, clm@fb.com,
        josef@toxicpanda.com, dsterba@suse.com
Cc:     linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org,
        zhangxiaoxu5@huawei.com, yanaijie@huawei.com, wqu@suse.com
References: <20221115171709.3774614-1-chenxiaosong2@huawei.com>
 <20221115171709.3774614-2-chenxiaosong2@huawei.com>
From:   Qu Wenruo <quwenruo.btrfs@gmx.com>
In-Reply-To: <20221115171709.3774614-2-chenxiaosong2@huawei.com>
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Precedence: bulk


On 2022/11/16 01:17, ChenXiaoSong wrote:
> As the potential sleeping under spin lock is hard to spot, we should add
> might_sleep() to some places.
> 
> Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>

Looks good.

We may want to add more in other locations, but this is really a good start.

Reviewed-by: Qu Wenruo <wqu@suse.com>

Thanks,
Qu
> ---
>   fs/btrfs/ctree.c  | 2 ++
>   fs/btrfs/qgroup.c | 2 ++
>   2 files changed, 4 insertions(+)
> 
> diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
> index a9543f01184c..809053e9cfde 100644
> --- a/fs/btrfs/ctree.c
> +++ b/fs/btrfs/ctree.c
> @@ -1934,6 +1934,8 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
>   	int min_write_lock_level;
>   	int prev_cmp;
>   
> +	might_sleep();
> +
>   	lowest_level = p->lowest_level;
>   	WARN_ON(lowest_level && ins_len > 0);
>   	WARN_ON(p->nodes[0] != NULL);
> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
> index 9334c3157c22..d0480b9c6c86 100644
> --- a/fs/btrfs/qgroup.c
> +++ b/fs/btrfs/qgroup.c
> @@ -779,6 +779,8 @@ static int update_qgroup_limit_item(struct btrfs_trans_handle *trans,
>   	int ret;
>   	int slot;
>   
> +	might_sleep();
> +
>   	key.objectid = 0;
>   	key.type = BTRFS_QGROUP_LIMIT_KEY;
>   	key.offset = qgroup->qgroupid;