Re: [patch] add file position info to proc

[Dave Hansen <hansendc@us.ibm.com>]

On Sun, 2007-03-25 at 15:45 -0800, Andrew Morton wrote:
> On Sat, 24 Mar 2007 23:04:09 +0100 Miklos Szeredi <miklos@szeredi.hu> wrote:
> 
> > This patch adds support for finding out the current file position,
> > open flags and possibly other info in the future.
> > 
> > These new entries are added:
> > 
> >   /proc/PID/fdinfo/FD
> >   /proc/PID/task/TID/fdinfo/FD
> > 
> > For each fd the information is provided in the following format:
> > 
> > pos:	1234
> > flags:	0100002
> 
> I've seen the idea mentioned once or twice, but not with any great
> enthusiasm.  Why does Linux want this feature?

We can also use it for checkpoint/restart.  When restarting, we need to
put back the files in the same state they were in when we checkpointed.
This would at least allow us to do normal file checkpointing in
userspace.

-- Dave