Comment # 10 on bug 997639 from Neil Brown

Sorry,  I didn't get to finish this, and I am now on leave.

We have two options.
1/ backport ea01a18494b3d7a91b2f1f2a6 and 
 
http://ozlabs.org/~akpm/mmotm/broken-out/autofs-use-dentry-flags-to-block-walks-during-expire.patch

or
2/ revert  47be6184 

I'm not convinced that 47be patch is really all that helpful, but it probably
makes sense to stay with mainline.
The two patches needing backporting are non-trivial so I wanted to review them
properly before committing them, and with everything else happening I didn't
manage that.
I have no reason to doubt them, except that I doubt everything.

Maybe you could look, Jeff,  before I get back?