linux-kernel - Re: [PATCH v1] f2fs: Fix discard bug on zoned block devices with 2MiB zone size

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Message-ID: <a24d66ad-4048-fd5c-ae47-2dd17c87bcbe@kernel.org>
Date:   Thu, 23 Mar 2023 23:17:38 +0800
From:   Chao Yu <chao@...nel.org>
To:     yonggil.song@...sung.com,
        "jaegeuk@...nel.org" <jaegeuk@...nel.org>,
        "linux-f2fs-devel@...ts.sourceforge.net" 
        <linux-f2fs-devel@...ts.sourceforge.net>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1] f2fs: Fix discard bug on zoned block devices with 2MiB
 zone size

On 2023/3/13 17:48, Yonggil Song wrote:
> When using f2fs on a zoned block device with 2MiB zone size, IO errors
> occurs because f2fs tries to write data to a zone that has not been reset.
> 
> The cause is that f2fs tries to discard multiple zones at once. This is
> caused by a condition in f2fs_clear_prefree_segments that does not check
> for zoned block devices when setting the discard range. This leads to
> invalid reset commands and write pointer mismatches.
> 
> This patch fixes the zoned block device with 2MiB zone size to reset one
> zone at a time.
> 
> Signed-off-by: Yonggil Song <yonggil.song@...sung.com>
> ---
>   fs/f2fs/segment.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index acf3d3fa4363..2b6cb6df623b 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1953,7 +1953,8 @@ void f2fs_clear_prefree_segments(struct f2fs_sb_info *sbi,
>   					(end - 1) <= cpc->trim_end)
>   				continue;
>   
> -		if (!f2fs_lfs_mode(sbi) || !__is_large_section(sbi)) {
> +		if (!f2fs_sb_has_blkzoned(sbi) &&

Could you please add one line comment here for this change?

Otherwise it looks good to me.

Thanks,

> +		    (!f2fs_lfs_mode(sbi) || !__is_large_section(sbi))) {
>   			f2fs_issue_discard(sbi, START_BLOCK(sbi, start),
>   				(end - start) << sbi->log_blocks_per_seg);
>   			continue;