[9fans] clone files and Srv->clone

[9fans] clone files and Srv->clone

[Sascha Retzki]

Evenin',


I've got a question about the process of cloning in the 9p(2) sense and
in the sense of e.g. webfs does: Is it the same?

Or, to explain my problem from the top-down perspective, I want my lil
file-server to have a clone-file. On read, a new directory with a tree
is created and the name of this new directory is returned. Is it that I
have to do that mostly manually, or can Srv->walk1 and Srv->clone help
me? If yes, how (rougly)? Or am I mistaken, and there is some all-in-one
solution to my problem (because many file-server do it in this way, I
assume there is some library-calls for that?)


Thanks, Sascha

Re: [9fans] clone files and Srv->clone

[Francisco J Ballesteros]

srv->clone clones a client fid. You can think of it like
doing a dup of a file descriptor. You obtain a new fid that is a clone
of the old one. Try man 5 clone.

Walk1 walks a name. For example, you might have a fid for your
/ file. After a walk1 "a" on that fid, your fid now points to "/a". See
man 5 walk.

You might do a clone file but that has nothing to do with walk and clone.
For example, you might arrange for your srv->open to create a new file
each time, and then make the fid point to it. That way, each open(2)
would obtain a cloned file.

Run for example ramfs with -D, play with touch ls and the like, and look
at the 9p messages printed by ramfs. Section 5 describes the whole
protocol.

hth

On 12/10/05, Sascha Retzki <sretzki@gmx.de> wrote:
> Evenin',
>
>
> I've got a question about the process of cloning in the 9p(2) sense and
> in the sense of e.g. webfs does: Is it the same?
>
> Or, to explain my problem from the top-down perspective, I want my lil
> file-server to have a clone-file. On read, a new directory with a tree
> is created and the name of this new directory is returned. Is it that I
> have to do that mostly manually, or can Srv->walk1 and Srv->clone help
> me? If yes, how (rougly)? Or am I mistaken, and there is some all-in-one
> solution to my problem (because many file-server do it in this way, I
> assume there is some library-calls for that?)
>
>
> Thanks, Sascha
>
>

Re: [9fans] clone files and Srv->clone

[Russ Cox]

As Nemo points out, Srv.clone and
clone files like in the network stack
are completely different things.

In the original 9P protocol, there was
a Tclone message that was identical in
functionality to a 9P2000 Twalk with
nname==0.  That's where the name
comes from.

Russ

Re: [9fans] clone files and Srv->clone

[Francisco J Ballesteros]

Sorry, that´s true. clone(5) is gone. Walk does both things now.

On 12/10/05, Russ Cox <rsc@swtch.com> wrote:
> As Nemo points out, Srv.clone and
> clone files like in the network stack
> are completely different things.
>
> In the original 9P protocol, there was
> a Tclone message that was identical in
> functionality to a 9P2000 Twalk with
> nname==0.  That's where the name
> comes from.
>
> Russ
>
>