Re: 2.4 Q: list of open files per inode?

[Jacob A <jacoba51-tmp@yahoo.com>]

Al,

I'm using the open/close call as a way for processes to register/unregister with a watchdog driver that I'm writing.
I thought that I can save the housekeeping within the driver, but it looks like It would be easier just to maintain my own list
and be done with it.

Jacob

----- Original Message ----
From: Al Viro <viro@ftp.linux.org.uk>
To: Jan Engelhardt <jengelh@computergmbh.de>
Cc: Jacob A <jacoba51-tmp@yahoo.com>; linux-kernel@vger.kernel.org
Sent: Thursday, July 19, 2007 7:38:10 PM
Subject: Re: 2.4 Q: list of open files per inode?

On Thu, Jul 19, 2007 at 01:41:03PM +0200, Jan Engelhardt wrote:
> 
> On Jul 19 2007 02:01, Jacob A wrote:
> >
> > How can a device driver go over the  list of all the files that are open on a
> > specific inode instance?
> 
> pseudo-code:
> 
> task_list_lock;
> for each process; do
>     lock_fdtable;
>     for each filedescriptor; do
>         do_something(fd->file_ptr);
>     unlock_fdtable;
> task_list_unlock;

Not again...

There are other things that can keep file open.  SCM_RIGHTS, references
held by syscall in progress, etc., etc.

The real question is why does driver want to do that?  Details, please...