[PATCH resend] vfs: Add ->statfs callback for pipefs
Andrew Morton
akpm at linux-foundation.org
Wed Aug 24 01:23:28 PDT 2011
On Wed, 24 Aug 2011 12:09:24 +0400 Cyrill Gorcunov <gorcunov at gmail.com> wrote:
> From: Pavel Emelyanov <xemul at parallels.com>
>
> This is done to make it possible to distinguish pipes
> from fifos when opening one via /proc/<pid>/fd/ link.
>
> Signed-off-by: Pavel Emelyanov <xemul at parallels.com>
> Reviewed-by: Tejun Heo <tj at kernel.org>
> Acked-by: Serge Hallyn <serge.hallyn at canonical.com>
> Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
> ---
> fs/pipe.c | 1 +
> 1 file changed, 1 insertion(+)
>
> Any objections to this one? It was a part of a patchset
> but can be treated independently so I'm re-sending it alone.
>
> Index: linux-2.6.git/fs/pipe.c
> ===================================================================
> --- linux-2.6.git.orig/fs/pipe.c
> +++ linux-2.6.git/fs/pipe.c
> @@ -1254,6 +1254,7 @@ out:
>
> static const struct super_operations pipefs_ops = {
> .destroy_inode = free_inode_nonrcu,
> + .statfs = simple_statfs,
> };
>
> /*
OK, I give up - how does it work?
<goes off and reads the kernel>
So it appears that the statfs call would previously return -ENOSYS, but
with this change the statfs will succeed and userspace can then inspect
f_type. Yes? I will fix your changelog by adding a description along these
lines.
And I'll ask you to fix it further by telling us why we want to do
this? The kernel has had this issue for a long time - why does it now
matter?
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