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

[Ian Kent <raven@themaw.net>]

On Tue, 29 Nov 2005, William H. Taber wrote:

> Ian Kent wrote:
> > We'll need to do an analysis of all callers of the revalidate method.
> You are right. Searching through the sources, it would appear that I 
> missed fixing autofs and devfs.  Everyone else just defines a revalidate 
> routine but doesn't call one.  You may find devfs to be interesting 
> because they have code to determine whether they need to release the 
> i_sem lock or not.  I am working on an updated patch to include the 
> changes needed for these two modules.

I've looked at devfs before but that bit of code sounds interesting to me.

The other thing that concerns me is that we may be increasing the latency 
of some code paths that need to be really fast. I was thinking that 
perhaps it might be good to try a change more in line with the locking 
used in link_patch_walk (ie. i_sem free revalidate) rather than that used 
in lookup_one_len. My only justification being that lookup is called to 
create stuff where revalidate is called to check stuff. I've been 
poking around and this change looks fairly difficult as well (I seem to 
remember you also looked at this).

Anyway, I'm keen to have a look at your patch.
Thanks much for your interest and help.

Ian