Re: [RFC] [PATCHv3 7/9] reiser4: batch discard support: actually implement the FITRIM ioctl handler.

[Edward Shishkin <edward.shishkin@gmail.com>]

On 10/21/2014 06:18 PM, Ivan Shapovalov wrote:
> On Tuesday 21 October 2014 at 12:14:02, Edward Shishkin wrote:	
>> On 10/21/2014 12:39 AM, Ivan Shapovalov wrote:
>>> On Monday 20 October 2014 at 12:54:13, Edward Shishkin wrote:	
>>>> On 08/17/2014 11:52 PM, Ivan Shapovalov wrote:
>>>>> [...]
>>>>> +		/*
>>>>> +		 * Grab some sane amount of space.
>>>>> +		 * We will allocate blocks until end of the partition or until
>>>>> +		 * the grabbed space is exhausted.
>>>>> +		 */
>>>>> +		ret = reiser4_grab_reserved(super, 0, BA_CAN_COMMIT | BA_SOME_SPACE);
>>>>   any "legitimate" user of the reserved space
>>>> will block on the mutex and eventually proceed. At the same time, given
>>>> a filesystem with (5% + eps) free space left, not using the reserved space
>>>> will result in trimming of (eps) blocks at a time.
>>>>
>>>> reiser4_grab_reserved() grabs space from the reserved area (5%).
>>>> This is needed to make sure that unlink(), truncate(), etc. won't
>>>> fail, if there is no free space on disk. I don't think that FITRIM
>>>> ioctl needs this reserved area.
>>> Well, IIUC, it doesn't hurt:
>>
>> "doesn't hurt" is not enough. If you want to take a resource,
>> you should be going to explain, why do you need this.
> I've explained the reason below... isn't it sufficient?


Sorry, but I don't see any explanation.

Thanks,
Edward.