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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 3F5A5FA3728 for ; Wed, 16 Oct 2019 16:50:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1898921A49 for ; Wed, 16 Oct 2019 16:50:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571244613; bh=sqgHreqTi1i3Tx4fYKNWwFE1NCar570i6YUyioSamHs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=I303RvbDD8pbUN82hTtW8NtiIVYHRpNuTkFIjCKJwZyL6KPi23jFuDwbFE0Q+JIGv xQr6hxdFj4KCH7rFWFxeWX3RdXlKsR60arhfQ0VYT+eNyy+hWAWXTHLIDvolB1v19F n9sn9lU9HHb58hyHlJCVdWz1L+b1/QGsQunl/NZk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405923AbfJPQuJ (ORCPT ); Wed, 16 Oct 2019 12:50:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:42606 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405336AbfJPQuJ (ORCPT ); Wed, 16 Oct 2019 12:50:09 -0400 Received: from localhost (li1825-44.members.linode.com [172.104.248.44]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 131FF2168B; Wed, 16 Oct 2019 16:50:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571244608; bh=sqgHreqTi1i3Tx4fYKNWwFE1NCar570i6YUyioSamHs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=y3KxXTSgx0HNgc35dznykNn4WPs1cwbSSyV+Q1ROXqEcuEFScltR+kjzdA2h+9Axi cqWgql0vuRPvZUZ6PEIJ0aoWK9dsazJYz5R58UeQSGUJDGnCXZMvwzb6qIn1mu+jVc NRC+CMy1wZpIRpf2cY0QchC8+5TcfEdz7W4AF528= Date: Wed, 16 Oct 2019 09:50:01 -0700 From: Greg Kroah-Hartman To: Pali =?iso-8859-1?Q?Roh=E1r?= Cc: Sasha Levin , devel@driverdev.osuosl.org, Valdis =?utf-8?Q?Kl=C4=93tnieks?= , Christoph Hellwig , linux-kernel@vger.kernel.org, Sasha Levin , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] staging: exfat: add exfat filesystem code to staging Message-ID: <20191016165001.GA639209@kroah.com> References: <20190828160817.6250-1-gregkh@linuxfoundation.org> <20190829205631.uhz6jdboneej3j3c@pali> <184209.1567120696@turing-police> <20190829233506.GT5281@sasha-vm> <20190830075647.wvhrx4asnkrfkkwk@pali> <20191016140353.4hrncxa5wkx47oau@pali> <20191016143113.GS31224@sasha-vm> <20191016160349.pwghlg566hh2o7id@pali> <20191016162211.GA505532@kroah.com> <20191016163231.dgvurzdqcifunw35@pali> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20191016163231.dgvurzdqcifunw35@pali> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, Oct 16, 2019 at 06:32:31PM +0200, Pali Rohár wrote: > On Wednesday 16 October 2019 09:22:11 Greg Kroah-Hartman wrote: > > On Wed, Oct 16, 2019 at 06:03:49PM +0200, Pali Rohár wrote: > > > > Can I assume you will be implementing TexFAT support once the spec is > > > > available? > > > > > > I cannot promise that I would implement something which I do not know > > > how is working... It depends on how complicated TexFAT is and also how > > > future exfat support in kernel would look like. > > > > > > But I'm interesting in implementing it. > > > > What devices need TexFAT? I thought it the old devices that used it are > > long obsolete and gone. How is this feature going to be tested/used? > > Hi Greg! Per 3.1.16 of exFAT specification [1], TexFAT extension is the > only way how to use more FAT tables, like in FAT32 (where you normally > have two FATs). Secondary FAT table can be used e.g. for redundancy or > data recovery. For FAT32 volumes, e.g. fsck.fat uses secondary FAT table > when first one is corrupted. > > Usage of just one FAT table in exFAT is just step backward from FAT32 as > secondary FAT table is sometimes the only way how to recover broken FAT > fs. So I do not think that exFAT is for old devices, but rather > non-exFAT is for old devices. Modern filesystems have journal or other > technique to do (fast|some) recovery, exFAT has nothing. > > And how is this feature going to be used? That depends on specification. > > [1] - https://docs.microsoft.com/en-us/windows/win32/fileio/exfat-specification#3116-numberoffats-field Ok, but given that the "only" os that can read/write the TexFAT extension is WinCE, and that os is obsolete these days, it might be hard to find images to test/validate against :) But hey, I'll take the patch if you write it, no objection! thanks, greg k-h