linux-kernel - Re: [PATCH] f2fs: prevent meta updates while checkpoint is in progress

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Message-ID: <20200331035419.GB79749@google.com>
Date:   Mon, 30 Mar 2020 20:54:19 -0700
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     Sahitya Tummala <stummala@...eaurora.org>
Cc:     Chao Yu <yuchao0@...wei.com>,
        linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] f2fs: prevent meta updates while checkpoint is in
 progress

On 03/26, Sahitya Tummala wrote:
> allocate_segment_for_resize() can cause metapage updates if
> it requires to change the current node/data segments for resizing.
> Stop these meta updates when there is a checkpoint already
> in progress to prevent inconsistent CP data.

I'd prefer to use f2fs_lock_op() in bigger coverage.

> 
> Signed-off-by: Sahitya Tummala <stummala@...eaurora.org>
> ---
>  fs/f2fs/gc.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 5bca560..6122bad 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -1399,8 +1399,10 @@ static int free_segment_range(struct f2fs_sb_info *sbi, unsigned int start,
>  	int err = 0;
>  
>  	/* Move out cursegs from the target range */
> +	f2fs_lock_op(sbi);
>  	for (type = CURSEG_HOT_DATA; type < NR_CURSEG_TYPE; type++)
>  		allocate_segment_for_resize(sbi, type, start, end);
> +	f2fs_unlock_op(sbi);
>  
>  	/* do GC to move out valid blocks in the range */
>  	for (segno = start; segno <= end; segno += sbi->segs_per_sec) {
> -- 
> Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.