On 2018/9/24 下午7:53, Anand Jain wrote:
> 
> 
> On 09/24/2018 06:58 PM, Qu Wenruo wrote:
>>
>>
>> On 2018/9/24 下午6:16, Anand Jain wrote:
>>> As of now _scratch_mkfs_sized check if the requested size is below 1G
>>> and forces the --mixed option for the mkfs.btrfs. Well the correct size
>>> at which we need to force the mixed option is 114294784bytes. Fix that.
>>
>> How this size is get from?
>> If it's from btrfs_min_dev_size(), I strongly recommend to add reference
>> here, and don't use the ugly intermediate number.
>>
>>
>> BTW, this number is related to mkfs profile.
>> If you really want to use some maximum number, please follow the max
>> possible value in btrfs_min_dev_size(), which should be 229M other than
>> 106M.
> 
>  Thanks for the comments. I completely missed out the point of other
>  group profile requiring more than ~115 bytes. Will fix.

I'd go a rounded number, like 256M.

Non of the number from btrfs_min_dev_size() is really easy to remember
nor makes sense out of btrfs realm.

And this also leaves a little more headroom for later modification
(although I hope such modification never happen)

Thanks,
Qu

>  Yep the ref for the size is btrfs_min_dev_size().
> 
> -Anand
> 
> 
>> Thanks,
>> Qu
>>
>>>
>>> Signed-off-by: Anand Jain <anand.jain@oracle.com>
>>> ---
>>>   common/rc | 4 +++-
>>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/common/rc b/common/rc
>>> index d5bb1feee2c3..bcdbf03e1bf0 100644
>>> --- a/common/rc
>>> +++ b/common/rc
>>> @@ -969,7 +969,9 @@ _scratch_mkfs_sized()
>>>       ;;
>>>       btrfs)
>>>       local mixed_opt=
>>> -    (( fssize <= 1024 * 1024 * 1024 )) && mixed_opt='--mixed'
>>> +    # minimum size that's needed without the mixed option.
>>> +    # Non mixed mode is also the default option.
>>> +    (( fssize < 114294784 )) && mixed_opt='--mixed'
>>>       $MKFS_BTRFS_PROG $MKFS_OPTIONS $mixed_opt -b $fssize $SCRATCH_DEV
>>>       ;;
>>>       jfs)
>>>
>>