Re: [PATCH 0/4] autofs4 - autofs needs a miscelaneous device for ioctls

[Ian Kent <raven@themaw.net>]

On Wed, 2008-02-27 at 20:40 -0800, Andrew Morton wrote:
> On Tue, 26 Feb 2008 12:21:58 +0900 (WST) Ian Kent <raven@themaw.net> wrote:
> 
> > 
> > Hi Andrew,
> > 
> > There is a problem with active restarts in autofs (that is to
> > say restarting autofs when there are busy mounts).
> > 
> > Currently autofs uses "umount -l" to clear active mounts at
> > restart. While using lazy umount works for most cases, anything
> > that needs to walk back up the mount tree to construct a path,
> > such as getcwd(2) and the proc file system /proc/<pid>/cwd, no
> > longer works because the point from which the path is constructed
> > has been detached from the mount tree.
> > 
> > The actual problem with autofs is that it can't reconnect to
> > existing mounts. Immediately one things of just adding the
> > ability to remount autofs file systems would solve it, but
> > alas, that can't work. This is because autofs direct mounts
> > and the implementation of "on demand mount and expire" of
> > nested mount trees have the file system mounted on top of
> > the mount trigger dentry.
> > 
> > To resolve this a miscellaneous device node for routing ioctl
> > commands to these mount points has been implemented for the
> > autofs4 kernel module.
> > 
> > For those wishing to test this out an updated user space daemon
> > is needed. Checking out and building from the git repo or
> > applying all the current patches to the 5.0.3 tar distribution
> > will do the trick. This is all available at the usual location
> > on kernel.org.
> > 
> 
> Could we please be a bit more specific than "the usual location"?

Yes, I should have been more specific.
I'll fix that.

> 
> Should autofs userspace have an entry in Documentation/Changes?

Sound like a sensible thing to do.
I'll include a patch for that when I re-post the patch set.

Ian