Re: [PATCH] autofs4 - detect invalid direct mount requests

[Ian Kent <raven@themaw.net>]

On Fri, 2008-06-20 at 09:00 -0400, Jeff Moyer wrote:
> Ian Kent <raven@themaw.net> writes:
> 
> > autofs v5 dierct and offset mounts within an autofs filesystem are
> > triggered by existing autofs triger mounts so the mount point dentry
> > must be positive. If the mount point dentry is negative then the
> > trigger doesn't exist so we can return fail immediately.
> 
> What are the conditions that lead us here in that case?

v5 doesn't need to get those dir/otherdir messages that we can't avoid
for v4.

Basically, attempts to access a non-existent directory in multi-mount
tree leads to a negative dentry being sent to the wait queue, but v5
direct and offset mounts must always have an existing (non-negative
dentry) directory upon which to mount. This is only relevant for
multi-mounts that don't have an explicit multi-mount root so that the
lookups occur within the autofs file system.

Sorry, I still can't think of a way to avoid this for v4.

Ian