vfs: add path_is_mountpoint() helper
authorIan Kent <ikent@redhat.com>
Wed, 23 Nov 2016 21:03:41 +0000 (08:03 +1100)
committerAl Viro <viro@zeniv.linux.org.uk>
Sun, 4 Dec 2016 01:51:35 +0000 (20:51 -0500)
commitc6609c0a1c34fc097152b28b496236625673924f
tree864cfb55fd8727e2a475ca44dd8d7df5a8488005
parentfb5f51c7425ebc808d91329257cbc963e2421368
vfs: add path_is_mountpoint() helper

d_mountpoint() can only be used reliably to establish if a dentry is
not mounted in any namespace. It isn't aware of the possibility there
may be multiple mounts using a given dentry that may be in a different
namespace.

Add helper functions, path_is_mountpoint(), that checks if a struct path
is a mountpoint for this case.

Link: http://lkml.kernel.org/r/20161011053358.27645.9729.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fs/mount.h
fs/namespace.c
include/linux/mount.h