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.
Thanks,
>
> Thanks,
> Junling
>
>> Thanks,
>>
>>>
>>> Signed-off-by: katao <ka...@xiaomi.com>
>>> Signed-off-by: Jaegeuk Kim <jaeg...@google.com>
>>> ---
>>> lib/libf2fs.c | 9 ++++++++-
>>> 1 file changed, 8 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/lib/libf2fs.c b/lib/libf2fs.c
>>> index 0c684d5..5f11796 100644
>>> --- a/lib/libf2fs.c
>>> +++ b/lib/libf2fs.c
>>> @@ -799,8 +799,15 @@ int get_device_info(int i)
>>> #ifdef BLKSSZGET
>>> if (ioctl(fd, BLKSSZGET, §or_size) < 0)
>>> MSG(0, "\tError: Using the default sector size\n");
>>> - else if (dev->sector_size < sector_size)
>>> + else if (dev->sector_size < sector_size){
>>> + /*
>>> + * wanted_total_sectors need to be reset by new
>>> + * sector_size.
>>> + */
>>> + c.wanted_total_sectors = (c.wanted_total_sectors *
>>> + dev->sector_size) / sector_size;
>>> dev->sector_size = sector_size;
>>> + }
>>> #endif
>>> #ifdef BLKGETSIZE64
>>> if (ioctl(fd, BLKGETSIZE64, &dev->total_sectors) < 0) {
>>>
>>
>>
>> .
>>
>
>
>
> .
>
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