From 43694d4bf843ddd34519e8e9de983deefeada699 Mon Sep 17 00:00:00 2001 From: Ian Kent Date: Wed, 29 Nov 2017 16:11:23 -0800 Subject: [PATCH] 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 Reviewed-by: NeilBrown Cc: Al Viro Cc: [4.11+] Cc: Colin Walters Cc: David Howells Cc: Ondrej Holy Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/autofs4/root.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c index d79ced9..82e8f6e 100644 --- a/fs/autofs4/root.c +++ b/fs/autofs4/root.c @@ -281,8 +281,8 @@ static int autofs4_mount_wait(const struct path *path, bool rcu_walk) 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_changed(struct path *path) */ 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; } -- 2.7.4