Re: [PATCH 3/3] btrfs: add helper function check device delete able

[Anand Jain <anand.jain@oracle.com>]

On 07/13/2018 07:28 PM, Nikolay Borisov wrote:
> 
> 
> On 13.07.2018 14:27, Anand Jain wrote:
>>
>>
>> On 07/12/2018 03:43 PM, Nikolay Borisov wrote:
>>>
>>>
>>> On 10.07.2018 21:22, Anand Jain wrote:
>>>> Move the section of the code which performs the check if the device is
>>>> indelible, move that into a helper function.
>>>>
>>>> Signed-off-by: Anand Jain <anand.jain@oracle.com>
>>>> ---
>>>>    fs/btrfs/volumes.c | 49
>>>> ++++++++++++++++++++++++++++++-------------------
>>>>    1 file changed, 30 insertions(+), 19 deletions(-)
>>>>
>>>> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
>>>> index 59a6d8f42c98..feb29c5b44f6 100644
>>>> --- a/fs/btrfs/volumes.c
>>>> +++ b/fs/btrfs/volumes.c
>>>> @@ -1945,6 +1945,33 @@ static inline u64 btrfs_num_devices(struct
>>>> btrfs_fs_info *fs_info)
>>>>        return num_devices;
>>>>    }
>>>>    +static struct btrfs_device *btrfs_device_delete_able(
>>>
>>> Ugliest name ever! So this function is not really a predicate, rather
>>> it's used to fetch the struct btrfs_device * to delete. So a more
>>> becoming name would be:
>>>
>>> btrfs_get_device_for_delete - though this a bit verbose.
>>>
>>> I guess btrfs_can_delete_device is more suitable if you want to follow
>>> this predicate style. At the very least, though, the correct form of the
>>> adjective is deletable so it should be btrfs_device_deletable. But as I
>>> said this function is not really used as a predicate.
>>
>>   Its a predicate, return of the device pointer is just a by-product.
>>   Will use btrfs_device_deletable().

> Then it's fundamentally wrong, a predicate should really return true or
> false. This function actually tries to acquire a device which will only
> happen if it meets certain criterion, so I'm inclined to say it's not
> really a predicate but rather tries to acquire a reference to a device
> which meets certain criteria.

  Ok. Will rename it, so that it won't look like predicate. However as
  btrfs_device.. should come fist based on the other functions, will
  use,  btrfs_device_get_for_delete()

Thanks, Anand


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