From: serge.hallyn@ubuntu.com
To: linux-kernel@vger.kernel.org
Cc: adityakali@google.com, tj@kernel.org, linux-api@vger.kernel.org,
        containers@lists.linux-foundation.org, cgroups@vger.kernel.org,
        akpm@linux-foundation.org, ebiederm@xmission.com,
        gregkh@linuxfoundation.org, lizefan@huawei.com, hannes@cmpxchg.org
Subject: Show virtualized dentry root in mountinfo for cgroupfs
Date: Sun, 17 Apr 2016 15:04:30 -0500
Message-Id: <1460923472-29370-1-git-send-email-serge.hallyn@ubuntu.com>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 510
Lines: 10

With the current cgroup namespace patches, the root dentry path of a
mount as shown in /proc/self/mountinfo is the full global cgroup
path.  It is common for userspace to use /proc/self/mountinfo to
search for cgroup mountpoints, and expect the root dentry path to
relate to the cgroup paths in /proc/self/cgroup.  Patch 2 in this
set therefore virtualizes the root dentry path relative to the
reader's cgroup namespace root.

Patch 1 fixes a bug in kernfs_path_from_node_locked() which is
exposed by patch 2.