On 2018/4/3 4:03, Jaegeuk Kim wrote:
> On 04/02, Chao Yu wrote:
>> On 2018/3/30 23:39, Jaegeuk Kim wrote:
>>> On 03/30, Junling Zheng wrote:
>>>> On 2018/3/30 19:26, Chao Yu wrote:
>>>>> On 2018/3/30 18:51, Junling Zheng wrote:
>>>>>> Hi,
>>>>>>
>>>>>> On 2018/3/30 17:28, Chao Yu wrote:
>>>>>>> Hi All,
>>>>>>>
>>>>>>> On 2018/3/28 1:19, Jaegeuk Kim wrote:
>>>>>>>> From: katao <ka...@xiaomi.com>
>>>>>>>>
>>>>>>>> The args of wanted_total_sectors is calculated based
>>>>>>>> on the DEFAULT_SECTOR_SIZE(512Bytes).get_device_info(i)
>>>>>>>> may be reset dev_sector_size, we should reset the number
>>>>>>>> of wanted_total_sectors.
>>>>>>>>
>>>>>>>> This bug was reported to Google Issue Tracker.
>>>>>>>> Link: https://issuetracker.google.com/issues/76407663
>>>>>>>
>>>>>>> I don't think this is the right way, since now we have changed previous
>>>>>>> sector_counter's meaning, some applications, for example, like xfstests 
>>>>>>> will get
>>>>>>> device's real sector size via blockdev --getsize64, then calculate 
>>>>>>> total wanted
>>>>>>> sector count by total_wanted_size / real_sector_size, if we changed 
>>>>>>> default
>>>>>>> sector size to 512bytes, xfstests will pass a wrong sector number, 
>>>>>>> result in
>>>>>>> getting wrong partition size.
>>>>>>>
>>>>>>> For something worse, in order to get the correct sector number, we have 
>>>>>>> to
>>>>>>> change the way of calculation method of xfstests for new mkfs, but how 
>>>>>>> can
>>>>>>> xfstests know the current version of mkfs is new or old...
>>>>>>>
>>>>>>> I think the change didn't consider backward compatibility of mkfs, so, 
>>>>>>> in order
>>>>>>> to keep that, we'd better to let user pass the right sector number 
>>>>>>> based on
>>>>>>> their device, or we can introduce a new parameter to indicate user 
>>>>>>> wanted total
>>>>>>> size.
>>>>>>>
>>>>>>> How do you think?
>>>>>>>
>>>>>>
>>>>>> Agree. It's not backward-compatible. Most users can pass the correct 
>>>>>> sector number
>>>>>> calculated by the real sector size. For those very few users using 512B 
>>>>>> despite of
>>>>>> the actual sector size, all we need to do is informing them the real 
>>>>>> sector size.
>>>>>
>>>>> The problem is via passed sector number, we can't know user has already 
>>>>> knew the
>>>>> real sector size or not, so we don't have any chance to info them.
>>>>>
>>>>
>>>> Yeah, we can't guess users' behaviors. And only when wanted size is over 
>>>> device size,
>>>> we can inform users the real sector size.
>>>
>>> So, current problem would be that wanted_total_sectors is given by:
>>> - device sector size in xfstests
>>> - 4KB in fs_mgr in Android
>>> - 512B in recovery in Android
>>>
>>> And, my concern is why user always needs to think about sector_size to give
>>> target image size, and I thought 512B would be good to set as a default 
>>> smallest
>>> value.
>>
>> Of course, IMO, the most direct way is let user pass image size to mkfs.f2fs
>> instead of caculated sector size, I think that will make all happy.
> 
> No, it can become too large number.
> 
>>
>>>
>>> Setting it 512B by default can give some confusion to users tho, it won't 
>>> hurt
>>> the existing partitions or images. So, I bet users will get noticed quickly,
>>> when formatting new partition under this rule.
>>
>> For those f2fs users, who makes image based on non-512B sector device, once 
>> they
>> upgrade mkfs.f2fs, they will encounter this issue, that may make bad 
>> reputation.
>>
>> For interface in f2fs private ioctl, sysfs entry, or syscall, we keep the 
>> rule
>> that once we want to do some change on it, we will not change the old 
>> interface
>> directly, instead, introduce a new one to keep backward compatibility of old
>> one. Still, I hope we can keep that rule in mkfs.f2fs parameter.
> 
> Okay, so in order to give more flexible ways, it'd be fine to add
> wanted_sector_size by "-w" so that we could blow out all the existing concern
> like this.

That's better.

> 
> From: katao <ka...@xiaomi.com>
> Date: Tue, 27 Mar 2018 13:25:46 +0800
> Subject: [PATCH] libf2fs,mkfs.f2fs: add wanted_sector_size for
>  wanted_total_sectors
> 
> The wanted_total_sectors was determined by device sector size, but sometimes
> we don't know precise sector_size by default. So, let's give 
> wanted_sector_size
> in such the ambiguous situation.
> 
> Signed-off-by: katao <ka...@xiaomi.com>
> Signed-off-by: Junling Zheng <zhengjunl...@huawei.com>
> Signed-off-by: Jaegeuk Kim <jaeg...@google.com>

Reviewed-by: Chao Yu <yuch...@huawei.com>

Thanks,


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