Re: [PATCH 1/2] f2fs: fix iostat lock protection

[Chao Yu]

On 2023/3/31 17:26, Bo Ye wrote:
> From: Qilin Tan <qilin.tan@xxxxxxxxxxxx>
>
> Made iostat lock irq safe to avoid potentinal deadlock.
>
> Deadlock scenario:
> f2fs_attr_store
>    -> f2fs_sbi_store
>    -> _sbi_store
>    -> spin_lock(sbi->iostat_lock)
>      <interrupt request>
>      -> scsi_end_request
>      -> bio_endio
>      -> f2fs_dio_read_end_io
>      -> f2fs_update_iostat
>      -> spin_lock_irqsave(sbi->iostat_lock)  ===> Dead lock here

Fixes: 61803e984307 ("f2fs: fix iostat related lock protection")
Fixes: a1e09b03e6f5 ("f2fs: use iomap for direct I/O")

> Signed-off-by: Qilin Tan <qilin.tan@xxxxxxxxxxxx>

Reviewed-by: Chao Yu <chao@xxxxxxxxxx>

Thanks,

> ---
>   fs/f2fs/sysfs.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> index 0b19163c90d4..fd238a68017e 100644
> --- a/fs/f2fs/sysfs.c
> +++ b/fs/f2fs/sysfs.c
> @@ -575,9 +575,9 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
>   	if (!strcmp(a->attr.name, "iostat_period_ms")) {
>   		if (t < MIN_IOSTAT_PERIOD_MS || t > MAX_IOSTAT_PERIOD_MS)
>   			return -EINVAL;
> -		spin_lock(&sbi->iostat_lock);
> +		spin_lock_irq(&sbi->iostat_lock);
>   		sbi->iostat_period_ms = (unsigned int)t;
> -		spin_unlock(&sbi->iostat_lock);
> +		spin_unlock_irq(&sbi->iostat_lock);
>   		return count;
>   	}
>   #endif