From patchwork Mon Nov 27 15:02:39 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: amulhern@redhat.com X-Patchwork-Id: 10076979 X-Patchwork-Delegate: snitzer@redhat.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id E00A46028E for ; Mon, 27 Nov 2017 15:02:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D0CFD28ECC for ; Mon, 27 Nov 2017 15:02:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C5AE228EEA; Mon, 27 Nov 2017 15:02:53 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 7276A28ECC for ; Mon, 27 Nov 2017 15:02:53 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5ABF1356E5; Mon, 27 Nov 2017 15:02:52 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0F5C960600; Mon, 27 Nov 2017 15:02:52 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 707B61800BDE; Mon, 27 Nov 2017 15:02:51 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id vARF2oF1003216 for ; Mon, 27 Nov 2017 10:02:50 -0500 Received: by smtp.corp.redhat.com (Postfix) id 289566056B; Mon, 27 Nov 2017 15:02:50 +0000 (UTC) Delivered-To: dm-devel@redhat.com Received: from localhost.localdomain.com (unknown [10.18.25.209]) by smtp.corp.redhat.com (Postfix) with ESMTP id F11AC60176; Mon, 27 Nov 2017 15:02:46 +0000 (UTC) From: amulhern@redhat.com To: dm-devel@redhat.com Date: Mon, 27 Nov 2017 10:02:39 -0500 Message-Id: <20171127150245.27959-1-amulhern@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-loop: dm-devel@redhat.com Cc: mulhern , snitzer@redhat.com Subject: [dm-devel] [PATCH 1/7] dm: documentation fix X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Mon, 27 Nov 2017 15:02:52 +0000 (UTC) X-Virus-Scanned: ClamAV using ClamSMTP From: mulhern Fixes: 1. The use of "exceeds" when the opposite of exceeds, falls below, was meant. 2. Properly speaking, a table can not exceed a threshold. It emphasizes the important point, which is that it is the userspace daemon's responsibility to check for low free space when a device is resumed, since it won't get a special event indicating low free space in that situation. Signed-off-by: mulhern --- Documentation/device-mapper/thin-provisioning.txt | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/Documentation/device-mapper/thin-provisioning.txt b/Documentation/device-mapper/thin-provisioning.txt index 1699a55..ef63996 100644 --- a/Documentation/device-mapper/thin-provisioning.txt +++ b/Documentation/device-mapper/thin-provisioning.txt @@ -112,9 +112,11 @@ $low_water_mark is expressed in blocks of size $data_block_size. If free space on the data device drops below this level then a dm event will be triggered which a userspace daemon should catch allowing it to extend the pool device. Only one such event will be sent. -Resuming a device with a new table itself triggers an event so the -userspace daemon can use this to detect a situation where a new table -already exceeds the threshold. + +No special event is triggered if a just resumed device's free space is below +the low water mark. However, resuming a device always triggers an +event; a userspace daemon should verify that free space exceeds the low +water mark when handling this event. A low water mark for the metadata device is maintained in the kernel and will trigger a dm event if free space on the metadata device drops below