Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751436AbdGQS7i (ORCPT ); Mon, 17 Jul 2017 14:59:38 -0400 Received: from mail-dm3nam03on0122.outbound.protection.outlook.com ([104.47.41.122]:62182 "EHLO NAM03-DM3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751320AbdGQS7g (ORCPT ); Mon, 17 Jul 2017 14:59:36 -0400 From: "Alex Ng (LIS)" To: Greg KH , KY Srinivasan CC: "linux-kernel@vger.kernel.org" , "devel@linuxdriverproject.org" , "olaf@aepfle.de" , "apw@canonical.com" , "vkuznets@redhat.com" , "jasowang@redhat.com" , "leann.ogasawara@canonical.com" , "marcelo.cerri@canonical.com" , Stephen Hemminger , Vyronas Tsingaras Subject: RE: [PATCH 1/2] Tools: hv: vss: Skip freezing filesystems backed by loop Thread-Topic: [PATCH 1/2] Tools: hv: vss: Skip freezing filesystems backed by loop Thread-Index: AQHS7ewRtpCCxWN3uUOfm9H+aM9iAKJYHV2AgABHPWA= Date: Mon, 17 Jul 2017 18:59:32 +0000 Message-ID: References: <1498420033-4914-1-git-send-email-kys@exchange.microsoft.com> <1498420066-5000-1-git-send-email-kys@exchange.microsoft.com> <20170717130002.GA1876@kroah.com> In-Reply-To: <20170717130002.GA1876@kroah.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: msip_labels: MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Enabled=True; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_SiteId=72f988bf-86f1-41af-91ab-2d7cd011db47; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Ref=https://api.informationprotection.azure.com/api/72f988bf-86f1-41af-91ab-2d7cd011db47; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Owner=alexng@microsoft.com; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_SetDate=2017-07-17T11:59:28.4194554-07:00; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Name=General; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Application=Microsoft Azure Information Protection; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Extended_MSFT_Method=Automatic; Sensitivity=General x-originating-ip: [2001:4898:80e8:1::4a] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;BN6PR21MB0180;7: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 x-ms-office365-filtering-correlation-id: 102aa92f-6050-462b-7dc8-08d4cd45f64d x-ms-office365-filtering-ht: Tenant x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:(300000500095)(300135000095)(300000501095)(300135300095)(22001)(300000502095)(300135100095)(2017030254075)(48565401081)(300000503095)(300135400095)(2017052603031)(201703131423075)(201703031133081)(300000504095)(300135200095)(300000505095)(300135600095)(300000506095)(300135500095);SRVR:BN6PR21MB0180; x-ms-traffictypediagnostic: BN6PR21MB0180: authentication-results: outbound.protection.outlook.com: dkim=none (message not signed) header.d=none; dmarc=none action=none header.from=microsoft.com; x-exchange-antispam-report-test: UriScan:(236129657087228)(9452136761055)(140211028294663)(198206253151910); x-microsoft-antispam-prvs: x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(100000700101)(100105000095)(100000701101)(100105300095)(100000702101)(100105100095)(61425038)(6040450)(601004)(2401047)(8121501046)(5005006)(2017060910075)(3002001)(93006095)(93001095)(10201501046)(100000703101)(100105400095)(6055026)(61426038)(61427038)(6041248)(20161123555025)(20161123564025)(20161123560025)(20161123558100)(201703131423075)(201702281528075)(201703061421075)(201703061406153)(20161123562025)(6072148)(100000704101)(100105200095)(100000705101)(100105500095);SRVR:BN6PR21MB0180;BCL:0;PCL:0;RULEID:(100000800101)(100110000095)(100000801101)(100110300095)(100000802101)(100110100095)(100000803101)(100110400095)(100000804101)(100110200095)(100000805101)(100110500095);SRVR:BN6PR21MB0180; x-forefront-prvs: 0371762FE7 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(6009001)(39850400002)(39450400003)(39840400002)(39860400002)(39410400002)(39400400002)(377454003)(13464003)(24454002)(3905003)(74316002)(6116002)(7696004)(4326008)(478600001)(10290500003)(2906002)(1511001)(8936002)(305945005)(7736002)(6506006)(8676002)(5660300001)(102836003)(7416002)(81166006)(86362001)(189998001)(9686003)(6246003)(38730400002)(54906002)(99286003)(25786009)(55016002)(2950100002)(5005710100001)(3660700001)(6436002)(33656002)(3280700002)(50986999)(54356999)(6636002)(76176999)(2561002)(53546010)(229853002)(77096006)(10090500001)(53936002)(14454004)(2900100001);DIR:OUT;SFP:1102;SCL:1;SRVR:BN6PR21MB0180;H:BN6PR21MB0689.namprd21.prod.outlook.com;FPR:;SPF:None;MLV:sfv;LANG:en; spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-originalarrivaltime: 17 Jul 2017 18:59:33.1550 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN6PR21MB0180 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id v6HIxiu2032686 Content-Length: 1584 Lines: 39 My apologies. The changelog comment should be more descriptive. Since a loop device is backed by a file, a backup will already result in its parent filesystem being frozen. It's sufficient to just freeze the parent filesystem, so we can skip the loop device. This avoids a situation where a loop device and its parent filesystem are both frozen and then thawed out of order. For example, if the loop device is enumerated first, we would thaw it while its parent filesystem is still frozen. The thaw operation fails and the loop device remains frozen. I'll work with KY to send an updated patch with a better comment. > -----Original Message----- > From: Greg KH [mailto:gregkh@linuxfoundation.org] > Sent: Monday, July 17, 2017 6:00 AM > To: KY Srinivasan > Cc: linux-kernel@vger.kernel.org; devel@linuxdriverproject.org; > olaf@aepfle.de; apw@canonical.com; vkuznets@redhat.com; > jasowang@redhat.com; leann.ogasawara@canonical.com; > marcelo.cerri@canonical.com; Stephen Hemminger > ; Alex Ng (LIS) ; > Vyronas Tsingaras > Subject: Re: [PATCH 1/2] Tools: hv: vss: Skip freezing filesystems backed by > loop > > On Sun, Jun 25, 2017 at 12:47:45PM -0700, kys@exchange.microsoft.com > wrote: > > From: Alex Ng > > > > Skip loop devices from the freeze/thaw operation. > > Ok, but why? What is the consequences of this? Please provide a much > better changelog comment, especially for something that is supposed to > be a "fix". > > thanks, > > greg k-h