[9fans] 9P and locking

[9fans] 9P and locking

[Alejo Sanchez]

Hi guys.

I'm doing a minimal user space 9P implementation for a special
distributed network storage. One of the features missing on the 9P
protocol is file locking. Do you know why it was kept outside? Or am I
missing something?

So far my plan to extend is to have messages mimicking fcntl, but
maybe that's not the best way to get it done. Did anyone work on
locking and would like to share their experience or opinion?

Cheers.

Alejo

Re: [9fans] 9P and locking

[Bruce Ellis]

See you in Madrid or read the paper.

brucee

On 11/1/06, Alejo Sanchez <alejos@gmail.com> wrote:
> Hi guys.
>
> I'm doing a minimal user space 9P implementation for a special
> distributed network storage. One of the features missing on the 9P
> protocol is file locking. Do you know why it was kept outside? Or am I
> missing something?
>
> So far my plan to extend is to have messages mimicking fcntl, but
> maybe that's not the best way to get it done. Did anyone work on
> locking and would like to share their experience or opinion?
>
> Cheers.
>
> Alejo
>

Re: [9fans] 9P and locking

[Anel Philippe]

Locking is implemented through DMEXCL bit. See open(2).

    Phil;

Alejo Sanchez a écrit :
> Hi guys.
>
> I'm doing a minimal user space 9P implementation for a special
> distributed network storage. One of the features missing on the 9P
> protocol is file locking. Do you know why it was kept outside? Or am I
> missing something?
>
> So far my plan to extend is to have messages mimicking fcntl, but
> maybe that's not the best way to get it done. Did anyone work on
> locking and would like to share their experience or opinion?
>
> Cheers.
>
> Alejo
>
>

Re: [9fans] 9P and locking

[Bruce Ellis]

yes, but that is not the locking that one may desire.
simplistic and effective but not a panacea.

brucee

On 11/1/06, Anel Philippe <xigh@free.fr> wrote:
> Locking is implemented through DMEXCL bit. See open(2).
>
>    Phil;
>
> Alejo Sanchez a écrit :
> > Hi guys.
> >
> > I'm doing a minimal user space 9P implementation for a special
> > distributed network storage. One of the features missing on the 9P
> > protocol is file locking. Do you know why it was kept outside? Or am I
> > missing something?
> >
> > So far my plan to extend is to have messages mimicking fcntl, but
> > maybe that's not the best way to get it done. Did anyone work on
> > locking and would like to share their experience or opinion?
> >
> > Cheers.
> >
> > Alejo
> >
> >
>
>

Re: [9fans] 9P and locking

[Charles Forsyth]

>> > So far my plan to extend is to have messages mimicking fcntl, but
>> > maybe that's not the best way to get it done. Did anyone work on
>> > locking and would like to share their experience or opinion?

in commercial unix database work i never found the in-built fcntl or record locking
particularly useful and did my own.  it was the usual `both too much
and too little' with the system's attempt, and thus i found it fairly pointless.
i wrote up something about it at the time but sadly that was years before
the dumps started.

Re: [9fans] 9P and locking

[Bruce Ellis]

yes. but you have no choice if a non plan9 machine requests
a strange locking operation.  either you handle it or you don't.

brucee

On 11/1/06, Charles Forsyth <forsyth@terzarima.net> wrote:
> >> > So far my plan to extend is to have messages mimicking fcntl, but
> >> > maybe that's not the best way to get it done. Did anyone work on
> >> > locking and would like to share their experience or opinion?
>
> in commercial unix database work i never found the in-built fcntl or record locking
> particularly useful and did my own.  it was the usual `both too much
> and too little' with the system's attempt, and thus i found it fairly pointless.
> i wrote up something about it at the time but sadly that was years before
> the dumps started.
>
>

Re: [9fans] 9P and locking

[Alejo Sanchez]

On 10/31/06, Charles Forsyth <forsyth@terzarima.net> wrote:
> >> > So far my plan to extend is to have messages mimicking fcntl, but
> >> > maybe that's not the best way to get it done. Did anyone work on
> >> > locking and would like to share their experience or opinion?
>
> in commercial unix database work i never found the in-built fcntl or record locking
> particularly useful and did my own.  it was the usual `both too much
> and too little' with the system's attempt, and thus i found it fairly pointless.
> i wrote up something about it at the time but sadly that was years before
> the dumps started.

The database is already doing it and it's quite fast and stable. I'm
only working on the remote file service.