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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5F309CD343F for ; Fri, 15 May 2026 04:38:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=A3ggIcTT9QpNE6xAWUcm+Edx6+JDZ1X1JlzR3+EsdbA=; b=Cpv0IRwirlD2yc+/xrXnWKPr61 oCGpvTREvVwOuV7bLDaCplIJ/24EtN6/+TFTpFDxzQ+a81UjSynCyJmTsZEIzujr+/F3e7W1T7Q0D 8NxblwSx2pqdxc5+AjTCVa28cWJAVUYLnuuDwr0R920waOXsHgtO9q7bgDjfR9XOMHQBy0tRB8VQ8 JVECgvwEvAHM7f3ZYg4KUNiCqRmpPMbleTy8Cvj8KTp6/Y13kj1jkfbFkTzgqq0qMLpSsV9zCF0Vy 24zghvRY0pLazpHSvBojKBsXQHR7XSjfjMUY+1c6ezwYiKJXwCXMCWtKrlqYQ9G0NbFqUS5ZN0ffv j72aqPcg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wNkJI-00000007K1F-1mxw; Fri, 15 May 2026 04:38:04 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wNkJF-00000007Jzr-2Bc3; Fri, 15 May 2026 04:38:02 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 1C6DB68BFE; Fri, 15 May 2026 06:37:58 +0200 (CEST) Date: Fri, 15 May 2026 06:37:57 +0200 From: Christoph Hellwig To: "H. Peter Anvin" Cc: kreijack@inwind.it, Goffredo Baroncelli , Christoph Hellwig , David Sterba , Andrew Morton , Catalin Marinas , Will Deacon , Ard Biesheuvel , Huacai Chen , WANG Xuerui , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Herbert Xu , Dan Williams , Chris Mason , David Sterba , Arnd Bergmann , Song Liu , Yu Kuai , Li Nan , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-crypto@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-arch@vger.kernel.org, linux-raid@vger.kernel.org Subject: Re: [PATCH 01/19] btrfs: require at least 4 devices for RAID 6 Message-ID: <20260515043757.GB3855@lst.de> References: <20260512052230.2947683-1-hch@lst.de> <20260512052230.2947683-2-hch@lst.de> <20260512114231.GG2558453@suse.cz> <20260513054742.GA1018@lst.de> <0a8d1ff4-f5a2-49e9-aa45-d25dbe4ded40@libero.it> <0507CCEF-0548-442F-8703-1D006B5E068B@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <0507CCEF-0548-442F-8703-1D006B5E068B@zytor.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260514_213801_702192_F411FBE9 X-CRM114-Status: GOOD ( 10.79 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, May 14, 2026 at 12:57:53PM -0700, H. Peter Anvin wrote: > That's what I'm saying – it should invoke the RAID-1 code under the > cover (as with 3 disks, D = P = Q.) Yes, if the btrfs maintainer cared for this setup that is what should be done. 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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0AF25CD4F3C for ; Fri, 15 May 2026 04:43:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=T/hO2nM6obiPLI1zOAulSX4HcLKRRFDLXpjykhPZ5AM=; b=th2yyRGv+KGMya 3rFCNG7daL6XI61UrmXjktVZhpHQtwEn41nKjjBziM6ZsEPSdQAUlLo0ErBYQJOAWIV2XOfBBkPv/ 25a0Qo5+AlfRX53cwAvqPneoZbyCopzlT/YoLnCXCRTyiRlyQR0LHfztGPcAW8+K8xbZgDdW7LX6d jbUF8iCC852qXYt5Rqv7ibh24Hc/jyg4Cjaw/d43utaDNqwP6J3uJ7Moq6xhamuByjynClI8DLejh 81lPGAuDVgHSfkz0gqHoEh8eJAcBIgJ46rqVyDY//iOdxi4PhyYJOxB8jMiB+Ucx5iDHRI/4+ZzzL bxdteu6qY6Qvb1REbGcg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wNkJI-00000007K1J-2CFr; Fri, 15 May 2026 04:38:04 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wNkJF-00000007Jzr-2Bc3; Fri, 15 May 2026 04:38:02 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 1C6DB68BFE; Fri, 15 May 2026 06:37:58 +0200 (CEST) Date: Fri, 15 May 2026 06:37:57 +0200 From: Christoph Hellwig To: "H. Peter Anvin" Cc: kreijack@inwind.it, Goffredo Baroncelli , Christoph Hellwig , David Sterba , Andrew Morton , Catalin Marinas , Will Deacon , Ard Biesheuvel , Huacai Chen , WANG Xuerui , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Herbert Xu , Dan Williams , Chris Mason , David Sterba , Arnd Bergmann , Song Liu , Yu Kuai , Li Nan , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-crypto@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-arch@vger.kernel.org, linux-raid@vger.kernel.org Subject: Re: [PATCH 01/19] btrfs: require at least 4 devices for RAID 6 Message-ID: <20260515043757.GB3855@lst.de> References: <20260512052230.2947683-1-hch@lst.de> <20260512052230.2947683-2-hch@lst.de> <20260512114231.GG2558453@suse.cz> <20260513054742.GA1018@lst.de> <0a8d1ff4-f5a2-49e9-aa45-d25dbe4ded40@libero.it> <0507CCEF-0548-442F-8703-1D006B5E068B@zytor.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <0507CCEF-0548-442F-8703-1D006B5E068B@zytor.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260514_213801_702192_F411FBE9 X-CRM114-Status: GOOD ( 10.79 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org T24gVGh1LCBNYXkgMTQsIDIwMjYgYXQgMTI6NTc6NTNQTSAtMDcwMCwgSC4gUGV0ZXIgQW52aW4g d3JvdGU6Cj4gVGhhdCdzIHdoYXQgSSdtIHNheWluZyDigJMgaXQgc2hvdWxkIGludm9rZSB0aGUg UkFJRC0xIGNvZGUgdW5kZXIgdGhlCj4gY292ZXIgKGFzIHdpdGggMyBkaXNrcywgRCA9IFAgPSBR LikKClllcywgaWYgdGhlIGJ0cmZzIG1haW50YWluZXIgY2FyZWQgZm9yIHRoaXMgc2V0dXAgdGhh dCBpcyB3aGF0IHNob3VsZApiZSBkb25lLgoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX18KbGludXgtcmlzY3YgbWFpbGluZyBsaXN0CmxpbnV4LXJpc2N2QGxp c3RzLmluZnJhZGVhZC5vcmcKaHR0cDovL2xpc3RzLmluZnJhZGVhZC5vcmcvbWFpbG1hbi9saXN0 aW5mby9saW51eC1yaXNjdgo=