Re: [RFC PATCH]autofs4: hang and proposed fix

[Ian Kent <raven@themaw.net>]

On Fri, 2 Dec 2005, Jeff Moyer wrote:

> ==> Regarding Re: [autofs] [RFC PATCH]autofs4: hang and proposed fix; Ian Kent <raven@themaw.net> adds:
> 
> raven> On Thu, 1 Dec 2005, William H. Taber wrote:
> >> > So the question is, can anyone provide an example of a path that, upon
> >> > calling autofs revalidate or lookup with the i_sem held, not be the
> >> path > that aquired it?
> 
> raven> So still no counter example!
> 
> >> Any other process calling lookup_one_len on a file in /net.
> 
> raven> I'm afraid this is not an example it's an assertion.  "Any other
> raven> process" is a little broad I think.  You'll need to be more
> raven> specific.
> 
> Well, I think we've determined that the reported problem doesn't happen
> with any in-tree callers.  The question, then, is do you want to fix the
> locking problem?  Two approaches were presented in this thread.  I don't
> really like the idea of the hack used by devfs, since it relies on implicit
> semantics.  I haven't given much thought to the second approach, though
> (are we sure it can be made to work?).  It may require a good deal of
> effort, but if it makes things work properly, it's worth considering.  I'm
> just not sure where it sits in the list of priorities, as I know you've got
> a lot on your plate, Ian.

It appears to me that the unhashed directory approach proposed by Will 
does not account for directories that exist but don't have current mounts.

I will re-read the posts, I expect I missed something, and give it more 
thought.

Ian