On Fri, 07 Dec 2007 04:51:37 +0000 David Woodhouse [off-list ref] wrote:

On Mon, 2007-11-26 at 15:17 -0700, Eric W. Biederman wrote:

quoted

Well I clearly goofed when I added the initial network namespace support
for /proc/net.  Currently things work but there are odd details visible
to user space, even when we have a single network namespace.

Since we do not cache proc_dir_entry dentries at the moment we can
just modify ->lookup to return a different directory inode depending
on the network namespace of the process looking at /proc/net, replacing
the current technique of using a magic and fragile follow_link method.

To accomplish that this patch:
- introduces a shadow_proc method to allow different dentries to
  be returned from proc_lookup.
- Removes the old /proc/net follow_link magic
- Fixes a weakness in our not caching of proc generic dentries.

As shadow_proc uses a task struct to decided which dentry to return we
can go back later and fix the proc generic caching without modifying any code that
uses the shadow_proc method.

Signed-off-by: Eric W. Biederman <redacted>
---
 fs/proc/generic.c       |   12 ++++++-
 fs/proc/proc_net.c      |   86 +++--------------------------------------------
 include/linux/proc_fs.h |    3 ++
 3 files changed, 19 insertions(+), 82 deletions(-)

(commit 2b1e300a9dfc3196ccddf6f1d74b91b7af55e416)

This seems to have broken the use of /proc/bus/usb as a mountpoint. It
always appears empty now, whatever's supposed to be mounted there.

Yes.  Denis and Eric are tossing around competing patches but afaik nobody
is happy with any of them.  Guys, could we get this sorted soonish please?