This is a note to let you know that I've just added the patch titled

autofs: revert "autofs: take more care to not update last_used on path walk"

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: autofs-revert-autofs-take-more-care-to-not-update-last_used-on-path-walk.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 43694d4bf843ddd34519e8e9de983deefeada699 Mon Sep 17 00:00:00 2001

From: Ian Kent raven@themaw.net Date: Wed, 29 Nov 2017 16:11:23 -0800 Subject: autofs: revert "autofs: take more care to not update last_used on path walk"

From: Ian Kent raven@themaw.net

commit 43694d4bf843ddd34519e8e9de983deefeada699 upstream.

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.t... 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: 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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- fs/autofs4/root.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-)

--- a/fs/autofs4/root.c +++ b/fs/autofs4/root.c @@ -281,8 +281,8 @@ static int autofs4_mount_wait(const stru pr_debug("waiting for mount name=%pd\n", path->dentry); status = autofs4_wait(sbi, path, NFY_MOUNT); pr_debug("mount wait done status=%d\n", status); - ino->last_used = jiffies; } + ino->last_used = jiffies; return status; }

@@ -321,21 +321,16 @@ static struct dentry *autofs4_mountpoint */ if (autofs_type_indirect(sbi->type) && d_unhashed(dentry)) { struct dentry *parent = dentry->d_parent; + struct autofs_info *ino; struct dentry *new;

new = d_lookup(parent, &dentry->d_name); if (!new) return NULL; - if (new == dentry) - dput(new); - else { - struct autofs_info *ino; - - ino = autofs4_dentry_ino(new); - ino->last_used = jiffies; - dput(path->dentry); - path->dentry = new; - } + ino = autofs4_dentry_ino(new); + ino->last_used = jiffies; + dput(path->dentry); + path->dentry = new; } return path->dentry; }

Patches currently in stable-queue which might be from raven@themaw.net are

queue-4.14/autofs-revert-autofs-fix-at_no_automount-not-being-honored.patch queue-4.14/autofs-revert-autofs-take-more-care-to-not-update-last_used-on-path-walk.patch