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

[lawrencedo99 at gmail.com]

On Wednesday, June 29, 2016 at 8:56:41 PM UTC+12, Johnny Billquist wrote:
> On 2016-06-28 00:51, Lawrence D’Oliveiro 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:
>>>
>>>> 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.

So why forbid users from creating them?

>> How do you delete a directory?
> 
> With the rmdir() system call nowadays.

So you give a path to rmdir(2), it removes the hard link to the directory from the parent in that path, and decrements its reference count. If the count goes to zero, the directory gets deleted.

But what if that directory is also part of a reference cycle? Its reference
count stays at 1, and it is not deleted.

What if all the directories in the cycle are only referenced within that cycle?

How do you delete those directories?