[Info-vax] Re; Spiralog, RMS Journaling (was Re: FREESPADRIFT)

[Johnny Billquist]

On 2016-06-28 00:51, lawrencedo99 at gmail.com wrote:
> On Tuesday, June 28, 2016 at 1:29:42 AM UTC+12, Johnny Billquist wrote:
>> On 2016-06-24 12:03, Lawrence D’Oliveiro wrote:
>>> On Thursday, June 23, 2016 at 10:27:12 PM UTC+12, Johnny Billquist wrote:
>>>> On 2016-06-22 09:27, Lawrence D’Oliveiro wrote:
>>>>> On Wednesday, June 22, 2016 at 3:30:03 AM UTC+12, Johnny Billquist wrote:
>>>>>>
>>>>>> Multiple hard links are not a problem for file system integrity.
>>>>>
>>>>> Yes they are.
>>>>
>>>> No, they are not. Like I said, you actually have hard links for
>>>> directories all over the place already, you just don't realize it.
>>>
>>> Further to your ingenious riposte regarding “.” and “..”, could you
>>> explain, given a directory which is a child of multiple parent
>>> directories, where you think “..” in that directory should point to?
>>
>> Congratulations. Now you find the reason why users are not allowed to
>> create their own hard links.
>
> Strange. Didn’t you say above that “multiple hard links are not a problem for file system integrity”? Aren’t you now admitting that they are? Otherwise why forbid them, right?

This is not an integrity issue. And it has nothing to do with cycles.

>>>>> Consider either (or both) of the following questions:
>>>>>
>>>>> * How do you prevent reference cycles?
>>>>
>>>> What is the problem with that? You already get those if you just follow
>>>> symlinks blindly as well.
>>>
>>> You don’t understand the difference between hard links and symlinks?
>>
>> I've heard people suggesting cycles many times. It's a strawman. There
>> are no problems with cycles ...
>
> How do you delete a directory?

With the rmdir() system call nowadays. The rmdir() system call in turn 
will just do three unlinks() atomically (along with some checking that 
the directory is empty.)

	Johnny