[Ocfs2-devel] [PATCH 1/3] fs: Document the reflink(2) system call.

[Joel Becker]

On Mon, May 04, 2009 at 06:36:58PM +1200, Michael Kerrisk wrote:
> On Mon, May 4, 2009 at 2:46 PM, Joel Becker <Joel.Becker at oracle.com> wrote:
> > On Sun, May 03, 2009 at 04:01:12AM -0400, Christoph Hellwig wrote:
> >> On Sat, May 02, 2009 at 11:15:01PM -0700, Joel Becker wrote:
> >> > int reflink(const char *oldpath, const char *newpath);
> >> >
> >> > The reflink(2) system call creates reference-counted links.  It creates
> >> > a new file that shares the data extents of the source file in a
> >> > copy-on-write fashion.  Its calling semantics are identical to link(2).
> >> > Once complete, programs see the new file as a completely separate entry.
> >>
> >> Just send this as a manpage to Michael, no need to duplicate a
> >> pseudo-manpage in the kernel tree.
> >
> >        The manpage style was just a convenient way to organize my
> > thoughts.  The goal was to document the behavior of reflink() for
> > implementors.  If the pseudo-manpage doesn't work, perhaps I'll try some
> > other form.
> 
> So, I'm late to this thread.  Is reflink() (to be) a user-visible syscall?

	Yes.  The actual call will be reflinkat(), as they're correct
that userspace can wrap reflink() around it.  I did have you on my todo
for notification as it settled down.

Joel

-- 

"Well-timed silence hath more eloquence than speech."  
         - Martin Fraquhar Tupper

Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker at oracle.com
Phone: (650) 506-8127