linux-kernel - Re: [PATCH 3/3] f2fs: change type for 'sbi->readdir

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Message-ID: <420531c0-2649-bf2a-140d-2f4f13036b0d@kernel.org>
Date:   Mon, 14 Nov 2022 22:59:23 +0800
From:   Chao Yu <chao@...nel.org>
To:     Yuwei Guan <ssawgyw@...il.com>, jaegeuk@...nel.org
Cc:     linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, Yuwei.Guan@...krlife.com
Subject: Re: [PATCH 3/3] f2fs: change type for 'sbi->readdir_ra'

On 2022/11/12 16:32, Yuwei Guan wrote:
> Before this patch, the varibale 'readdir_ra' takes effect if it's equal
> to '1' or not, so we can change type for it from 'int' to 'bool'.
> 
> Signed-off-by: Yuwei Guan <Yuwei.Guan@...krlife.com>
> ---
>   fs/f2fs/dir.c   | 7 +++----
>   fs/f2fs/f2fs.h  | 2 +-
>   fs/f2fs/super.c | 2 +-
>   fs/f2fs/sysfs.c | 5 +++++
>   4 files changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> index 21960a899b6a..06d9bf98f5ae 100644
> --- a/fs/f2fs/dir.c
> +++ b/fs/f2fs/dir.c
> @@ -1000,13 +1000,12 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
>   	struct fscrypt_str de_name = FSTR_INIT(NULL, 0);
>   	struct f2fs_sb_info *sbi = F2FS_I_SB(d->inode);
>   	struct blk_plug plug;
> -	bool readdir_ra = sbi->readdir_ra == 1;
>   	bool found_valid_dirent = false;
>   	int err = 0;
>   
>   	bit_pos = ((unsigned long)ctx->pos % d->max);
>   
> -	if (readdir_ra)
> +	if (sbi->readdir_ra)
>   		blk_start_plug(&plug);
>   
>   	while (bit_pos < d->max) {
> @@ -1064,14 +1063,14 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
>   			goto out;
>   		}
>   
> -		if (readdir_ra)
> +		if (sbi->readdir_ra)
>   			f2fs_ra_node_page(sbi, le32_to_cpu(de->ino));
>   
>   		ctx->pos = start_pos + bit_pos;
>   		found_valid_dirent = true;
>   	}
>   out:
> -	if (readdir_ra)
> +	if (sbi->readdir_ra)

I don't think this is the right way... due to below case:

if (sbi->readdir_ra)	// readdir_ra is 1 by default
	blk_start_plug(&plug);

if (sbi->readdir_ra)	// readdir_ra is updated to 0, it will miss to unplug.
	blk_finish_plug(&plug);

Thanks,

>   		blk_finish_plug(&plug);
>   	return err;
>   }
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index e6355a5683b7..384840216e7f 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1693,7 +1693,7 @@ struct f2fs_sb_info {
>   	unsigned int total_node_count;		/* total node block count */
>   	unsigned int total_valid_node_count;	/* valid node block count */
>   	int dir_level;				/* directory level */
> -	int readdir_ra;				/* readahead inode in readdir */
> +	bool readdir_ra;			/* readahead inode in readdir */
>   	u64 max_io_bytes;			/* max io bytes to merge IOs */
>   
>   	block_t user_block_count;		/* # of user blocks */
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index f18ae5410b2c..da304861890f 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -2202,7 +2202,7 @@ static void f2fs_tuning_parameters(struct f2fs_sb_info *sbi, bool is_remount)
>   	}
>   
>   	if (!is_remount)
> -		sbi->readdir_ra = 1;
> +		sbi->readdir_ra = true;
>   }
>   
>   static int f2fs_remount(struct super_block *sb, int *flags, char *data)
> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> index df27afd71ef4..53fbbb87dd0f 100644
> --- a/fs/f2fs/sysfs.c
> +++ b/fs/f2fs/sysfs.c
> @@ -649,6 +649,11 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
>   		return count;
>   	}
>   
> +	if (!strcmp(a->attr.name, "readdir_ra")) {
> +		sbi->readdir_ra = !!t;
> +		return count;
> +	}
> +
>   	*ui = (unsigned int)t;
>   
>   	return count;