From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A48ECC35657 for ; Fri, 21 Feb 2020 16:33:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7B3E020578 for ; Fri, 21 Feb 2020 16:33:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="B0FelwNx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727775AbgBUQd1 (ORCPT ); Fri, 21 Feb 2020 11:33:27 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:45768 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726613AbgBUQd1 (ORCPT ); Fri, 21 Feb 2020 11:33:27 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582302805; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=BUt7yxaGqyhaBTF6KME7cZTH0QCIcSm1V6IEK/6dFnM=; b=B0FelwNxyRVtPqWe8d7KIkurZnqVJcy2I0dGPCIxfoYrhoUfn9jNTciNsgnjFGn0EI5PqH 3ED+WYlkx4qACcEyr0nN2B06oHGANi3FhYQBf/gXLGmsCJfQKxAEf5gmtlQAhGe6PRdPmd fJSFMJivQ7perayDuQJw6ESnttB9elw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-314-lXsEKvoKOOGLgNW6yuNVXw-1; Fri, 21 Feb 2020 11:33:24 -0500 X-MC-Unique: lXsEKvoKOOGLgNW6yuNVXw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EA0E319057A4; Fri, 21 Feb 2020 16:33:22 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-122-163.rdu2.redhat.com [10.10.122.163]) by smtp.corp.redhat.com (Postfix) with ESMTP id 40AC48B55C; Fri, 21 Feb 2020 16:33:21 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <158204549488.3299825.3783690177353088425.stgit@warthog.procyon.org.uk> <158204561120.3299825.5242636508455859327.stgit@warthog.procyon.org.uk> <1897788.1582295034@warthog.procyon.org.uk> To: Jann Horn Cc: dhowells@redhat.com, Al Viro , raven@themaw.net, Miklos Szeredi , Christian Brauner , Linux API , linux-fsdevel , kernel list Subject: Re: [PATCH 15/19] vfs: Add superblock notifications [ver #16] MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <2031797.1582302800.1@warthog.procyon.org.uk> Date: Fri, 21 Feb 2020 16:33:20 +0000 Message-ID: <2031798.1582302800@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jann Horn wrote: > (And as in the other case, the s->s_count increment will probably have > to be moved above the add_watch_to_object(), unless you hold the > sb_lock around it?) It shouldn't matter as I'm holding s->s_umount across the add and increment. That prevents the watch from being removed: watch_sb() would have to get the lock first to do that. It also deactivate_locked_super() from removing all the watchers. I can move it before, but I probably have to drop s_umount before I can call put_super(). David