New pseudo-filesystem: nsfs. Targets of /proc/*/ns/* live there now.
It's not mountable (not even registered, so it's not in /proc/filesystems,
etc.). Files on it *are* bindable - we explicitly permit that in do_loopback().
This stuff lives in fs/nsfs.c now; proc_ns_fget() moved there as well.
get_proc_ns() is a macro now (it's simply returning ->i_private; would
have been an inline, if not for header ordering headache).
proc_ns_inode() is an ex-parrot. The interface used in procfs is
ns_get_path(path, task, ops) and ns_get_name(buf, size, task, ops).
Dentries and inodes are never hashed; a non-counting reference to dentry
is stashed in ns_common (removed by ->d_prune()) and reused by ns_get_path()
if present. See ns_get_path()/ns_prune_dentry/nsfs_evict() for details
of that mechanism.
As the result, proc_ns_follow_link() has stopped poking in nd->path.mnt;
it does nd_jump_link() on a consistent <vfsmount,dentry> pair it gets
from ns_get_path().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
a) make get_proc_ns() return a pointer to struct ns_common
b) mirror ns_ops in dentry->d_fsdata of ns dentries, so that
is_mnt_ns_file() could get away with fewer dereferences.
That way struct proc_ns becomes invisible outside of fs/proc/*.c
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Split the proc namespace stuff out into linux/proc_ns.h.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: netdev@vger.kernel.org
cc: Serge E. Hallyn <serge.hallyn@ubuntu.com>
cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
