From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sg-1-11.ptr.blmpb.com (sg-1-11.ptr.blmpb.com [118.26.132.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3A7BB21772A for ; Wed, 17 Dec 2025 07:41:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=118.26.132.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765957282; cv=none; b=PkHbX8cQzsVjiLddd4jSEwpzICxdfV0cvc+YTD8T5O7/cv312PohC/rbmaptSEUWb2zDIaI55Pbgt+ufH8A1WOrHTn+nRl8/vBEqaJ9gWSThoXzFGHAkwRqQbdG7Zm9K4u5BSW0FzBnztS6XyQtwkX6IqkCXO2r170TdxdyiOJM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765957282; c=relaxed/simple; bh=gc7s9z0mCMLd31I/fcVEjVE4T8EBwefE/UsTn3a39MM=; h=From:Subject:Message-Id:Mime-Version:Content-Type:Date:References: Cc:In-Reply-To:To; b=eWKeTTOtd8XGkZwxWMTANwoyGHHDcfPj9JYlxT/D63Bi5P6XIuzj9BR7hMZuNndce+k2vvYBxbTQTB1keGHv04+igrpcD31vOyBtrroXsc7GnnKGJ6TxX0t6EU4VFTkDe6XPoOY0GkWMZE5eATNcjhREE+3K5+SsKQZYhphwKLQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=fnnas.com; spf=pass smtp.mailfrom=fnnas.com; dkim=pass (2048-bit key) header.d=fnnas-com.20200927.dkim.feishu.cn header.i=@fnnas-com.20200927.dkim.feishu.cn header.b=c/S33tsy; arc=none smtp.client-ip=118.26.132.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=fnnas.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fnnas.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fnnas-com.20200927.dkim.feishu.cn header.i=@fnnas-com.20200927.dkim.feishu.cn header.b="c/S33tsy" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; s=s1; d=fnnas-com.20200927.dkim.feishu.cn; t=1765957273; h=from:subject:mime-version:from:date:message-id:subject:to:cc: reply-to:content-type:mime-version:in-reply-to:message-id; bh=gc7s9z0mCMLd31I/fcVEjVE4T8EBwefE/UsTn3a39MM=; b=c/S33tsykDLNjTChPyhTgv+3hMEGSK6qjlzO3k9EuJprU075ODzQNaX28Eh+hjzR6H3B4L gFVwX9q+Fzce3s6rRc/CpI5PO6G6Hrs2QfP0Rm8PFoa+7wRoH8k7KwLFiW6XrYeNFerZ72 WZer5BczLfhfYJrLQGFlNsR2shcD+JLeqbfcxf6mmLxX0wOEI8LbnDFFqtWLVGCHq8+fr2 Z443jy+bCjnajZOAuoSNg2ofgaLhg7g17AJcuMKwa7oLalO19dEP1dr09To5sEPLhqwzwi jqqbtwfWDWD8lCHONyNTVKmgTmDxFM9ex7+3mg5Osw68IAuIt6Vf4Uz0BgNw5A== From: "Yu Kuai" Subject: Re: Issues with md raid 1 on kernel 6.18 after booting kernel 6.19-rc1 once Reply-To: yukuai@fnnas.com Message-Id: Precedence: bulk X-Mailing-List: linux-raid@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Original-From: Yu Kuai Content-Transfer-Encoding: quoted-printable Received: from [192.168.1.104] ([39.182.0.136]) by smtp.feishu.cn with ESMTPS; Wed, 17 Dec 2025 15:41:10 +0800 Content-Type: text/plain; charset=UTF-8 Date: Wed, 17 Dec 2025 15:41:08 +0800 Content-Language: en-US References: <8fd97a33-eb5a-4c88-ac8a-bfa1dd2ced61@fnnas.com> <619a9b00-43dd-4897-8bb0-9ff29a760f52@gmail.com> <7cff4b89-eeff-4048-8af3-ef9d76bdedf8@molgen.mpg.de> User-Agent: Mozilla Thunderbird Cc: , , , , , "Linus Torvalds" , In-Reply-To: <7cff4b89-eeff-4048-8af3-ef9d76bdedf8@molgen.mpg.de> X-Lms-Return-Path: To: "Paul Menzel" Hi, =E5=9C=A8 2025/12/17 15:33, Paul Menzel =E5=86=99=E9=81=93: > Dear Kuai, > > > Am 17.12.25 um 08:17 schrieb Yu Kuai: > >> =E5=9C=A8 2025/12/17 15:13, BugReports =E5=86=99=E9=81=93: >>> >>> ... >>> >>> We'll have to backport following patch into old kernels to make >>> new arrays to assemble in old kernels. .... >>> >>> The md array which i am talking about was not created with kernel=20 >>> 6.19, it was created sometime in 2024. >>> >>> It was just used in kernel 6.19 and that broke compatibility with >>> my 6.18 kernel. >> >> I know, I mean any array that is created or assembled in new kernels >> will now have lsb field stored in metadata. This field is not >> defined in old kernels and that's why array can't assembled in old >> kernels, due to unknown metadata. >> >> This is what we have to do for new features, and we're planning to >> avoid the forward compatibility issue with the above patch that I >> mentioned. > Is there really no way around it? Just testing a new kernel and being=20 > able to go back must be supported in my opinion, at least between one=20 > or two LTS versions. As I said, following patch should be backported to LTS kernels to avoid the= problem. https://lore.kernel.org/linux-raid/20251103125757.1405796-5-linan666@huawei= cloud.com > > > Kind regards, > > Paul --=20 Thansk, Kuai