RK> It has advisory file locking and plenty of things use that; it���s
RK> mandatory locking that it���s (now) missing.

What is the difference between advisary and mandatory?

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In article <1873491786@f172.n1.z21.fsxnet>,
candycane <candycane@f172.n1.z21.fsxnet> wrote:
> RK> It has advisory file locking and plenty of things use that; its
> RK> mandatory locking that its (now) missing.
>
>What is the difference between advisary and mandatory?

What is the difference between somebody advising you to do something vs.
them insisting you do it?

--
Senator Marsha Blackburn (R-TN), who sits on the Judiciary Committee, said it was
"extremely inappropriate" for the president to nominate a Supreme Court justice on a
day ending with the letter "Y", and she said that "Biden is putting the demands of the
radical progressive left ahead of what is best for our nation."

On 26/08/2023 17:20, Kenny McCormack wrote:
> In article <1873491786@f172.n1.z21.fsxnet>,
> candycane <candycane@f172.n1.z21.fsxnet> wrote:
>> RK> It has advisory file locking and plenty of things use that; its
>> RK> mandatory locking that its (now) missing.
>>
>> What is the difference between advisary and mandatory?
>
> What is the difference between somebody advising you to do something vs.
> them insisting you do it?
>
Its the difference between a sign saying 'no entry' and a steel bollard
rising up out of the road and smashing your suspension...
--
“The ultimate result of shielding men from the effects of folly is to
fill the world with fools.”

Herbert Spencer

candycane@f172.n1.z21.fsxnet (candycane) writes:
>> It has advisory file locking and plenty of things use that; it’s
>> mandatory locking that it’s (now) missing.
>
> What is the difference between advisary and mandatory?

An advisory lock suspends a process (or returns an error) when it tries
to acquire a lock over a region of a file that already has an advisory
lock on it. IO operations aren’t affected.

A mandatory lock additionally suspends a process when it tries to
perform IO on a portion of a file which is locked by another process.

Both are (usually) divided into read locks (which allow many concurrent
readers, but no writers) and write locks (which are completely exclusive
to one process).

--
https://www.greenend.org.uk/rjk/

KM> What is the difference between somebody advising you to do something vs.
KM> them insisting you do it?

Oh, so advisory is a recommendation and mandatory prevents file access lower
level?

Also, I'd say a simple solution would be to save the pid, and check if it's
still running. If it's not, give a warning to check data integrity and such,
but still let you acquire the lock.

-----------------------------------
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On 2023-08-25 21:09, candycane wrote:
> KM> What is the difference between somebody advising you to do something vs.
> KM> them insisting you do it?
>
> Oh, so advisory is a recommendation and mandatory prevents file access lower
> level?

Yes.

> Also, I'd say a simple solution would be to save the pid, and check if it's
> still running. If it's not, give a warning to check data integrity and such,
> but still let you acquire the lock.

Yes, the kernel can keep tables of what process locked a file, and
supply hooks or tools to kill the process and the locks it had. Not
saying it does, I don't know.

--
Cheers,
Carlos E.R.

Carlos E. R. <robin_listas@es.invalid> wrote:
> On 2023-08-25 21:09, candycane wrote:
>> KM> What is the difference between somebody advising you to do something vs.
>> KM> them insisting you do it?
>>
>> Oh, so advisory is a recommendation and mandatory prevents file access lower
>> level?
>
> Yes.
>
>
>> Also, I'd say a simple solution would be to save the pid, and check if it's
>> still running. If it's not, give a warning to check data integrity and such,
>> but still let you acquire the lock.
>
> Yes, the kernel can keep tables of what process locked a file, and
> supply hooks or tools to kill the process and the locks it had. Not
> saying it does, I don't know.

I thought mandatory file locks were recently removed from the kernel.

On 2023-09-02 16:30, Jerry Peters wrote:
> Carlos E. R. <robin_listas@es.invalid> wrote:
>> On 2023-08-25 21:09, candycane wrote:
>>> KM> What is the difference between somebody advising you to do something vs.
>>> KM> them insisting you do it?
>>>
>>> Oh, so advisory is a recommendation and mandatory prevents file access lower
>>> level?
>>
>> Yes.
>>
>>
>>> Also, I'd say a simple solution would be to save the pid, and check if it's
>>> still running. If it's not, give a warning to check data integrity and such,
>>> but still let you acquire the lock.
>>
>> Yes, the kernel can keep tables of what process locked a file, and
>> supply hooks or tools to kill the process and the locks it had. Not
>> saying it does, I don't know.
>
> I thought mandatory file locks were recently removed from the kernel.

Oh, sorry, I was not referring to an specific OS.

--
Cheers,
Carlos E.R.