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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 82679C0650E for ; Mon, 1 Jul 2019 08:53:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 52E5420645 for ; Mon, 1 Jul 2019 08:53:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728042AbfGAIxG convert rfc822-to-8bit (ORCPT ); Mon, 1 Jul 2019 04:53:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57336 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726442AbfGAIxF (ORCPT ); Mon, 1 Jul 2019 04:53:05 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1E43F308FC4D; Mon, 1 Jul 2019 08:52:55 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-219.rdu2.redhat.com [10.10.120.219]) by smtp.corp.redhat.com (Postfix) with ESMTP id 173CA19C6A; Mon, 1 Jul 2019 08:52:50 +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: <7a288c2c-11a1-87df-9550-b247d6ce3010@infradead.org> References: <7a288c2c-11a1-87df-9550-b247d6ce3010@infradead.org> <156173701358.15650.8735203424342507015.stgit@warthog.procyon.org.uk> <156173703546.15650.14319137940607993268.stgit@warthog.procyon.org.uk> To: Randy Dunlap Cc: dhowells@redhat.com, viro@zeniv.linux.org.uk, Casey Schaufler , Stephen Smalley , Greg Kroah-Hartman , nicolas.dichtel@6wind.com, raven@themaw.net, Christian Brauner , keyrings@vger.kernel.org, linux-usb@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/6] Adjust watch_queue documentation to mention mount and superblock watches. [ver #5] MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <8211.1561971170.1@warthog.procyon.org.uk> Content-Transfer-Encoding: 8BIT Date: Mon, 01 Jul 2019 09:52:50 +0100 Message-ID: <8212.1561971170@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Mon, 01 Jul 2019 08:53:05 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Randy Dunlap wrote: > I'm having a little trouble parsing that sentence. > Could you clarify it or maybe rewrite/modify it? > Thanks. How about: * ``info_filter`` and ``info_mask`` act as a filter on the info field of the notification record. The notification is only written into the buffer if:: (watch.info & info_mask) == info_filter This could be used, for example, to ignore events that are not exactly on the watched point in a mount tree by specifying NOTIFY_MOUNT_IN_SUBTREE must not be set, e.g.:: { .type = WATCH_TYPE_MOUNT_NOTIFY, .info_filter = 0, .info_mask = NOTIFY_MOUNT_IN_SUBTREE, .subtype_filter = ..., } as an event would be only permissible with this filter if:: (watch.info & NOTIFY_MOUNT_IN_SUBTREE) == 0 David