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Subject: RE: RE: [PATCH v0] f2fs: allow direct read for zoned device
Reply-To: eunhee83.rho@samsung.com
Sender: Eunhee Rho <eunhee83.rho@samsung.com>
From:   Eunhee Rho <eunhee83.rho@samsung.com>
To:     Jaegeuk Kim <jaegeuk@kernel.org>
CC:     "chao@kernel.org" <chao@kernel.org>,
        "linux-f2fs-devel@lists.sourceforge.net" 
        <linux-f2fs-devel@lists.sourceforge.net>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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Date:   Mon, 01 Aug 2022 13:06:07 +0900
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Precedence: bulk

>On 07/29, Eunhee Rho wrote:
>> For zoned devices, f2fs forbids direct IO and forces buffered IO
>> to serialize write IOs. However, the constraint does not apply to
>> read IOs.
>> 
>> Signed-off-by: Eunhee Rho <eunhee83.rho@samsung.com>
>> ---
>>  fs/f2fs/f2fs.h | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index d0f428aef34b..f69731f17402 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -4471,7 +4471,7 @@ static inline bool f2fs_force_buffered_io(struct inode *inode,
>>  	 * for blkzoned device, fallback direct IO to buffered IO, so
>>  	 * all IOs can be serialized by log-structured write.
>>  	 */
>> -	if (f2fs_sb_has_blkzoned(sbi))
>> +	if (f2fs_sb_has_blkzoned(sbi) && (rw == WRITE))
>>  		return true;
>
>Actually we don't need to check the device type, but rely on the
>filesystem allocation policy like the below lfs mode. Can we remove this
>line simply?
>
>>  	if (f2fs_lfs_mode(sbi) && (rw == WRITE)) {
>>  		if (block_unaligned_IO(inode, iocb, iter))
>> -- 
>> 2.25.1
>

Yes, I will reflect on the next patch.
Thanks.