Subject: fusermount -u fails
From: "John A. Sullivan III" <jsullivan@opensourcedevel.com>
Date: Tue, 02 Mar 2010 00:02:16 -0500

Hello, all.  I'm struggling to get sshfs working in a vserver for use
with X2Go (www.x2go.org).  I am running kernel 2.6.28.7 with
vs2.3.0.36.7 on CentOS 5.4 with a Debian Lenny guest.  I am able to
mount the sshfs file system but I am not able to do an fusermount -u.
It returns:

fusermount: failed to clone namespace: Operation not permitted

Current ccapabilities are:
SECURE_MOUNT
SECURE_REMOUNT
BINARY_MOUNT

The user attempting to do the fusermount -u is a member of fuse group
which has rw access to /dev/fuse.

How do I get this to work?

Just for kicks I tried adding the NAMESPACE ccapability but vserver
complains Unknown ccap 'NAMESPACE' - not that I really understand what
that capability would do :-(

I tried setting setgid on fusermount; that didn't work.  Since it is
already setuid, I thought I'd add the SETUID capability:
vattribute --xid 40061 --bcap SETUID
but got the same error.

For kicks, I added SYS_ADMIN and received a different error:
fusermount: failed to mark mounts slave: Invalid argument

Of course, I certainly don't want to grant SYS_ADMIN.  Any help would be
greatly appreciated.  X2Go is working generally well in a vserver but it
cannot clean up after itself if I don't solve this.  Thanks - John