Re: kjournald keeps reference to namespace

["Björn Steinbrink" <B.Steinbrink@gmx.de>]

On 2006.02.18 02:35:47 +0100, Herbert Poetzl wrote:
> 
> Hi Folks!
> 
> when creating a private namespace (CLONE_NS) and
> then mounting an ext3 filesystem, a new kernel
> thread (kjournald) is created, which keeps a
> reference to the namespace, which after the the
> process exits, remains and blocks access to the
> block device, as it is still bd_claim-ed.
> 
> this leaves a private namespace behind and a
> block device which cannot be opened exclusively.
> unmount is not an option, as the namespace is
> not longer reachable.
> 
> this behaviour seems to be there since ever,
> well since namespaces and kjournald exists :)
> 
> the following 'cruel' hack 'solves' this issue

In daemonize() a new thread gets cleaned up and 'merged' with init_task.
The current fs_struct is handled there, but not the current namespace.
The following patch adds the namespace part.

Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de>
---


diff -NurpP --minimal linux-2.6.16-rc4/kernel/exit.c linux-2.6.16-rc4-ns/kernel/exit.c
--- linux-2.6.16-rc4/kernel/exit.c	2006-02-18 13:59:59.000000000 +0100
+++ linux-2.6.16-rc4-ns/kernel/exit.c	2006-02-18 14:04:26.000000000 +0100
@@ -360,6 +360,8 @@ void daemonize(const char *name, ...)
 	fs = init_task.fs;
 	current->fs = fs;
 	atomic_inc(&fs->count);
+	exit_namespace(current);
+	current->namespace = init_task.namespace;
  	exit_files(current);
 	current->files = init_task.files;
 	atomic_inc(&current->files->count);