linux-kernel - Re: [f2fs-dev] [PATCH 2/2] f2fs: don't overwrite node block by SSR

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Message-ID: <2be8ba18-21ed-a990-70d1-12be80ed13d2@huawei.com>
Date:   Wed, 8 Mar 2017 20:30:46 +0800
From:   Chao Yu <yuchao0@...wei.com>
To:     Jaegeuk Kim <jaegeuk@...nel.org>, <linux-kernel@...r.kernel.org>,
        <linux-fsdevel@...r.kernel.org>,
        <linux-f2fs-devel@...ts.sourceforge.net>
Subject: Re: [f2fs-dev] [PATCH 2/2] f2fs: don't overwrite node block by SSR

On 2017/3/7 5:51, Jaegeuk Kim wrote:
> This patch fixes that SSR can overwrite previous warm node block consisting of
> a node chain since the last checkpoint.

Good catch!

Need to consider the impact to other accesser, e.g. is_checkpointed_data,
add_discard_addrs?

Thanks,

> 
> Fixes: 5b6c6be2d878 ("f2fs: use SSR for warm node as well")
> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> ---
>  fs/f2fs/segment.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 2ae36d04d03e..684b869e1861 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1177,6 +1177,12 @@ static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del)
>  		if (f2fs_discard_en(sbi) &&
>  			!f2fs_test_and_set_bit(offset, se->discard_map))
>  			sbi->discard_blks--;
> +
> +		/* don't overwrite by SSR to keep node chain */
> +		if (se->type == CURSEG_WARM_NODE) {
> +			if (!f2fs_test_and_set_bit(offset, se->ckpt_valid_map))
> +				se->ckpt_valid_blocks++;
> +		}
>  	} else {
>  		if (!f2fs_test_and_clear_bit(offset, se->cur_valid_map)) {
>  #ifdef CONFIG_F2FS_CHECK_FS
>