Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1033865AbbKFVXo (ORCPT ); Fri, 6 Nov 2015 16:23:44 -0500 Received: from mail-wm0-f49.google.com ([74.125.82.49]:33249 "EHLO mail-wm0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1033402AbbKFVXm (ORCPT ); Fri, 6 Nov 2015 16:23:42 -0500 Date: Fri, 6 Nov 2015 21:23:38 +0000 From: Sami Tolvanen To: device-mapper development Cc: Will Drewry , Kees Cook , Mike Snitzer , Mandeep Baines , linux-kernel@vger.kernel.org, Mikulas Patocka , Mark Salyzyn Subject: Re: [dm-devel] [PATCH 0/4] dm verity: add support for error correction Message-ID: <20151106212338.GA19557@google.com> References: <1446688954-29589-1-git-send-email-samitolvanen@google.com> <563B066C.6050202@redhat.com> <20151106190634.GA2813@google.com> <563CFD6F.4040009@redhat.com> <20151106202750.GA11849@google.com> <563D1614.5010501@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <563D1614.5010501@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 776 Lines: 16 On Fri, Nov 06, 2015 at 10:05:24PM +0100, Zdenek Kabelac wrote: > So how do you want to correctly 'restore' missing full sectors > with just 0.8% data overhead ?? We use interleaving. Each byte in a 4k block is part of a different Reed-Solomon block, which means an entire lost 4k data block looks like a single error. When we also spread the bytes that form a single Reed-Solomon block across the partition, we end up being able to correct several megabytes of consecutive corrupted blocks with very small space overhead. Sami -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/