autofs: revert "autofs: take more care to not update last_used on path walk"
authorIan Kent <raven@themaw.net>
Thu, 30 Nov 2017 00:11:23 +0000 (16:11 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 30 Nov 2017 02:40:43 +0000 (18:40 -0800)
commit43694d4bf843ddd34519e8e9de983deefeada699
treedca9964a3f55959a461860ff8bdcee5c9d4b3034
parentb6e8e12c0aeb5fbf1bf46c84d58cc93aedede385
autofs: revert "autofs: take more care to not update last_used on path walk"

While commit 092a53452bb7 ("autofs: take more care to not update
last_used on path walk") helped (partially) resolve a problem where
automounts were not expiring due to aggressive accesses from user space
it has a side effect for very large environments.

This change helps with the expire problem by making the expire more
aggressive but, for very large environments, that means more mount
requests from clients.  When there are a lot of clients that can mean
fairly significant server load increases.

It turns out I put the last_used in this position to solve this very
problem and failed to update my own thinking of the autofs expire
policy.  So the patch being reverted introduces a regression which
should be fixed.

Link: http://lkml.kernel.org/r/151174729420.6162.1832622523537052460.stgit@pluto.themaw.net
Fixes: 092a53452b ("autofs: take more care to not update last_used on path walk")
Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: NeilBrown <neilb@suse.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: <stable@vger.kernel.org> [4.11+]
Cc: Colin Walters <walters@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Ondrej Holy <oholy@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/autofs4/root.c