Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751970AbdF3Twi (ORCPT ); Fri, 30 Jun 2017 15:52:38 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:44585 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751919AbdF3Twg (ORCPT ); Fri, 30 Jun 2017 15:52:36 -0400 From: Nick Terrell To: Timofey Titovets CC: Kernel Team , Chris Mason , Yann Collet , Adam Borowski , David Sterba , "squashfs-devel@lists.sourceforge.net" , linux-btrfs , Linux Kernel Subject: Re: [PATCH v2 0/4] Add xxhash and zstd modules Thread-Topic: [PATCH v2 0/4] Add xxhash and zstd modules Thread-Index: AQHS8Q+7Y1RQvKI8f0afZNAwD2yH+KI9ntUA//++aoA= Date: Fri, 30 Jun 2017 19:52:10 +0000 Message-ID: <8C0B630F-01E0-459E-BAD6-44F8A68E1858@fb.com> References: <20170629194108.1674498-1-terrelln@fb.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: gmail.com; dkim=none (message not signed) header.d=none;gmail.com; dmarc=none action=none header.from=fb.com; x-originating-ip: [2620:10d:c090:200::7:b7a7] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;DM5PR15MB1209;20:UyAhkTp941U3zWVYAuBtxoSHjBKfqniBgYlBtPq02nSNKuv77MBhd9QZt23tKIDKOlk6yC2x4UAZ1/i5WU3H0UGXsXItb6GAS+i0NDX2tUQP/t2yiAw3MmwtDMIZzKtqon1Ebqv6+Aq1IzGTwlU6GP41gq33CLp7r+Mv7kzXT3Y= x-ms-office365-filtering-correlation-id: e913e652-6fc4-4604-20eb-08d4bff17f13 x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:(300000500095)(300135000095)(300000501095)(300135300095)(22001)(300000502095)(300135100095)(2017030254075)(300000503095)(300135400095)(2017052603031)(201703131423075)(201703031133081)(300000504095)(300135200095)(300000505095)(300135600095)(300000506095)(300135500095);SRVR:DM5PR15MB1209; x-ms-traffictypediagnostic: DM5PR15MB1209: x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:(236129657087228); x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(100000700101)(100105000095)(100000701101)(100105300095)(100000702101)(100105100095)(6040450)(601004)(2401047)(8121501046)(5005006)(10201501046)(100000703101)(100105400095)(93006095)(93001095)(3002001)(6041248)(20161123562025)(20161123560025)(20161123564025)(20161123555025)(20161123558100)(201703131423075)(201702281528075)(201703061421075)(201703061406153)(6072148)(100000704101)(100105200095)(100000705101)(100105500095);SRVR:DM5PR15MB1209;BCL:0;PCL:0;RULEID:(100000800101)(100110000095)(100000801101)(100110300095)(100000802101)(100110100095)(100000803101)(100110400095)(100000804101)(100110200095)(100000805101)(100110500095);SRVR:DM5PR15MB1209; x-forefront-prvs: 0354B4BED2 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(6009001)(39840400002)(39450400003)(39400400002)(39410400002)(39850400002)(86362001)(6116002)(14454004)(2906002)(8936002)(6486002)(77096006)(102836003)(36756003)(3280700002)(1411001)(3660700001)(54356999)(5660300001)(50986999)(76176999)(25786009)(305945005)(189998001)(2900100001)(33656002)(4326008)(229853002)(6506006)(6512007)(110136004)(38730400002)(6246003)(82746002)(53936002)(39060400002)(83716003)(6436002)(8676002)(7736002)(54906002)(99286003)(81166006)(6916009)(2950100002)(478600001);DIR:OUT;SFP:1102;SCL:1;SRVR:DM5PR15MB1209;H:DM5PR15MB1753.namprd15.prod.outlook.com;FPR:;SPF:None;MLV:ovrnspm;PTR:InfoNoRecords;LANG:en; spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="utf-8" Content-ID: MIME-Version: 1.0 X-MS-Exchange-CrossTenant-originalarrivaltime: 30 Jun 2017 19:52:10.5128 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR15MB1209 X-OriginatorOrg: fb.com X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-06-30_12:,, signatures=0 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 base64 to 8bit by mail.home.local id v5UJqf85015904 Content-Length: 486 Lines: 11 > If i understood all correctly, > zstd can compress (decompress) data in way compatible with gzip (zlib) > Do that also true for in kernel library? The zstd command line tool can decompress gzip/zlib compressed data, and can compress in the gzip format. However, the zstd format is not compatible with zlib, so gzip/zlib cannot decompress zstd compressed data. The zstd kernel module can only compress and decompress the zstd format, and can't decompress zlib/gzip compressed data.