Re: [PATCH] f2fs: honor per-I/O write streams for direct writes

[Chao Yu <chao@kernel.org>]

On 6/10/26 08:40, Jaegeuk Kim wrote:
> On 05/22, Wenjie Qi wrote:
>> io_uring can pass a per-I/O write stream through kiocb->ki_write_stream,
>> and block direct I/O propagates that value to bio->bi_write_stream.
>>
>> F2FS added FDP stream mapping for DATA writes, but its direct write
>> submit hook always rewrites bio->bi_write_stream from the inode write
>> hint and F2FS temperature. As a result, a direct write with an explicit
>> io_uring write_stream is submitted to the F2FS-selected stream instead
>> of the user-requested stream.
>>
>> Validate an explicit write stream before starting F2FS direct I/O, pass
>> the kiocb through the iomap private pointer, and preserve the per-I/O
>> stream in the direct write bio. When no per-I/O stream is supplied, keep
>> using the existing F2FS temperature-to-stream mapping.
>>
>> Fixes: 42f7a7a50a33 ("f2fs: map data writes to FDP streams")
>> Signed-off-by: Wenjie Qi <qiwenjie@xiaomi.com>
>> ---
>>  fs/f2fs/file.c | 30 +++++++++++++++++++++++++++---
>>  1 file changed, 27 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>> index 71385ca4163d..20d6e7ab7416 100644
>> --- a/fs/f2fs/file.c
>> +++ b/fs/f2fs/file.c
>> @@ -5074,17 +5074,36 @@ static int f2fs_dio_write_end_io(struct kiocb *iocb, ssize_t size, int error,
>>  	return 0;
>>  }
>>  
>> +static bool f2fs_valid_write_stream(struct f2fs_sb_info *sbi, u8 write_stream)
>> +{
>> +	int i;
>> +
>> +	if (!write_stream)
>> +		return true;
>> +	if (!f2fs_is_multi_device(sbi))
>> +		return write_stream <= bdev_max_write_streams(sbi->sb->s_bdev);
>> +
>> +	for (i = 0; i < sbi->s_ndevs; i++)
>> +		if (write_stream > bdev_max_write_streams(FDEV(i).bdev))
>> +			return false;
>> +	return true;
>> +}
>> +
>>  static void f2fs_dio_write_submit_io(const struct iomap_iter *iter,
>>  					struct bio *bio, loff_t file_offset)
>>  {
>>  	struct inode *inode = iter->inode;
>>  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>> +	struct kiocb *iocb = iter->private;
>>  	enum log_type type = f2fs_rw_hint_to_seg_type(sbi, inode->i_write_hint);
>>  	enum temp_type temp = f2fs_get_segment_temp(sbi, type);
>>  
>>  	bio->bi_write_hint = f2fs_io_type_to_rw_hint(sbi, DATA, temp);
>> -	bio->bi_write_stream =
>> -		f2fs_io_type_to_write_stream(bio->bi_bdev, DATA, temp);
>> +	if (iocb->ki_write_stream)
>> +		bio->bi_write_stream = iocb->ki_write_stream;
>> +	else
>> +		bio->bi_write_stream =
>> +			f2fs_io_type_to_write_stream(bio->bi_bdev, DATA, temp);
> 
> Let me apply as below.
> 
>         bio->bi_write_stream =
> +               iocb->ki_write_stream ? iocb->ki_write_stream :
>                 f2fs_io_type_to_write_stream(bio->bi_bdev, DATA, temp);

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,