From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753976AbcK1CMf (ORCPT ); Sun, 27 Nov 2016 21:12:35 -0500 Received: from out5-smtp.messagingengine.com ([66.111.4.29]:56704 "EHLO out5-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754126AbcK1CMS (ORCPT ); Sun, 27 Nov 2016 21:12:18 -0500 X-ME-Sender: X-Sasl-enc: XeeZQZS+9S1QLwj+WE8JvjiyJVcTE5bMY0/fKFq9Z6Fb 1480299136 Subject: [PATCH 6/7] autofs - dont hold spin lock over direct mount expire From: Ian Kent To: Andrew Morton Cc: autofs mailing list , Kernel Mailing List , "Eric W. Biederman" , linux-fsdevel , Omar Sandoval , Al Viro Date: Mon, 28 Nov 2016 10:12:14 +0800 Message-ID: <148029913453.27779.15747032937407838983.stgit@pluto.themaw.net> In-Reply-To: <148029910861.27779.4517883721395202453.stgit@pluto.themaw.net> References: <148029910861.27779.4517883721395202453.stgit@pluto.themaw.net> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ian Kent Commit 7cbdb4a286 altered the autofs indirect mount expire to not hold a spin lock during the expire check. The direct mount expire needs the same treatment because to make autofs expires namespace aware may_umount_tree() needs to to use a similar method to may_umount() when checking if a mount tree is in use. This means may_umount_tree() will end up taking the namespace_sem for the check so the autofs direct mount expire won't be allowed to hold a spin lock over the check. Signed-off-by: Ian Kent Cc: Al Viro Cc: Eric W. Biederman Cc: Omar Sandoval --- fs/autofs4/expire.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c index 13178bf..57725d4 100644 --- a/fs/autofs4/expire.c +++ b/fs/autofs4/expire.c @@ -310,26 +310,29 @@ struct dentry *autofs4_expire_direct(struct super_block *sb, now = jiffies; timeout = sbi->exp_timeout; - spin_lock(&sbi->fs_lock); - ino = autofs4_dentry_ino(root); - /* No point expiring a pending mount */ - if (ino->flags & AUTOFS_INF_PENDING) - goto out; if (!autofs4_direct_busy(mnt, root, timeout, do_now)) { + spin_lock(&sbi->fs_lock); + ino = autofs4_dentry_ino(root); + /* No point expiring a pending mount */ + if (ino->flags & AUTOFS_INF_PENDING) { + spin_unlock(&sbi->fs_lock); + goto out; + } ino->flags |= AUTOFS_INF_WANT_EXPIRE; spin_unlock(&sbi->fs_lock); synchronize_rcu(); - spin_lock(&sbi->fs_lock); if (!autofs4_direct_busy(mnt, root, timeout, do_now)) { + spin_lock(&sbi->fs_lock); ino->flags |= AUTOFS_INF_EXPIRING; init_completion(&ino->expire_complete); spin_unlock(&sbi->fs_lock); return root; } + spin_lock(&sbi->fs_lock); ino->flags &= ~AUTOFS_INF_WANT_EXPIRE; + spin_unlock(&sbi->fs_lock); } out: - spin_unlock(&sbi->fs_lock); dput(root); return NULL;