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

[Will Taber <wtaber@us.ibm.com>]

Ian Kent wrote:
> 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.
> 
It doesn't consider that case.  You had mentioned it but I had forgotten.

Will