Message-ID: <a0c55b6d-a325-d40d-e030-bc936ef592fe@kernel.org>
Date:   Fri, 3 Dec 2021 14:51:18 +0800
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Subject: Re: [f2fs-dev] [PATCH 5/6] f2fs: implement iomap operations
Content-Language: en-US
To:     Jaegeuk Kim <jaegeuk@kernel.org>,
        Eric Biggers <ebiggers@kernel.org>
Cc:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net
References: <20211116214510.2934905-1-jaegeuk@kernel.org>
 <20211116214510.2934905-5-jaegeuk@kernel.org>
 <b36e2d44-4834-3931-6a32-4fa52d1d7785@kernel.org>
 <YahIf3UlhuxJT1O4@sol.localdomain>
 <1ba0f002-42c7-b085-0c54-6071664ba79b@kernel.org>
 <YakPrVPz5+qQm3kQ@sol.localdomain> <YakXMV0UvBV7TVwe@google.com>
 <YakX38onzsW5Ef8B@google.com> <YakzVAkHAVMueJwe@sol.localdomain>
 <Yak4cxU6htgQk7ck@google.com> <Yak6gtXthBRK3eeM@google.com>
From:   Chao Yu <chao@kernel.org>
In-Reply-To: <Yak6gtXthBRK3eeM@google.com>
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On 2021/12/3 5:28, Jaegeuk Kim wrote:
> On 12/02, Jaegeuk Kim wrote:
>> On 12/02, Eric Biggers wrote:
>>> On Thu, Dec 02, 2021 at 11:00:47AM -0800, Jaegeuk Kim wrote:
>>>> On 12/02, Jaegeuk Kim wrote:
>>>>> On 12/02, Eric Biggers wrote:
>>>>>> On Thu, Dec 02, 2021 at 10:04:11PM +0800, Chao Yu wrote:
>>>>>>> On 2021/12/2 12:15, Eric Biggers wrote:
>>>>>>>> On Thu, Dec 02, 2021 at 11:10:41AM +0800, Chao Yu wrote:
>>>>>>>>> Why not relocating this check before f2fs_map_blocks()?
>>>>>>>
>>>>>>> Wait, it supports DIO in multi-device image after commit 	71f2c8206202
>>>>>>> ("f2fs: multidevice: support direct IO"), how about
>>>>>>> checking with f2fs_allow_multi_device_dio()?
>>>>>>>
>>>>>>> Thanks,
>>>>>>>
>>>>>>
>>>>>> Okay, that was not the case when I sent this patch originally.  We'll need to
>>>>>> update this to support multiple devices.
>>>>>
>>>>> Chao/Eric, does this make sense?
>>>>>
>>>>> --- a/fs/f2fs/data.c
>>>>> +++ b/fs/f2fs/data.c
>>>>> @@ -4070,11 +4070,10 @@ static int f2fs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
>>>>>                  }
>>>>>                  if (WARN_ON_ONCE(!__is_valid_data_blkaddr(map.m_pblk)))
>>>>>                          return -EINVAL;
>>>>> -               iomap->addr = blks_to_bytes(inode, map.m_pblk);
>>>>>
>>>>> -               if (WARN_ON_ONCE(f2fs_is_multi_device(F2FS_I_SB(inode))))
>>>>> -                       return -EINVAL;
>>>>> -               iomap->bdev = inode->i_sb->s_bdev;
>>>>> +               iomap->bdev = map->m_multidev_dio ? map.m_bdev :
>>>>
>>>> correction:			map.m_multidev_dio
>>>>
>>>
>>> I guess so, but why doesn't f2fs_map_blocks() just always set m_bdev to the
>>> correct block device?  What is the point of m_multidev_dio?
>>
>> It seems we can simply assign iomap->bdev = map.m_bdev, and remove
>> map->m_multidev_dio.
> 
> Ok, it was used in previous get_block flow, but I think it'd be worth to keep it
> to show by f2fs_map_blocks tracepoint.

Yes, it was added for that.

Thanks,

> 
>>
>>>
>>> - Eric
>>
>>
>> _______________________________________________
>> Linux-f2fs-devel mailing list
>> Linux-f2fs-devel@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> 
> 
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