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

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Date:   Tue, 15 Nov 2022 00:27:16 +0800
From:   Yuwei Guan <ssawgyw@...il.com>
To:     Chao Yu <chao@...nel.org>, 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 2022/11/14 22:59, Chao Yu wrote:
> 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);
>
Hi Chao,

Thanks for the review and pointing it out.

I will update it and send v1.

> 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;