From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CABEC40B38C for ; Mon, 12 Oct 2026 10:55:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791802507; cv=none; b=Um15tekhqR7N29T29Q1llPYJ7K2QwKp37Zoex6Tp+ZmlVAj963oyl4RFSeFD+xXdNacJfqCOsh3Sg6I7/UK9WE+DdM0fgs8FvNVePF3FDeXRhEFlMaQwIHn5pH9AZWZ3v9UX0gwv0FG3H5ZoEonzbJfFkP/kntjQxnJQUCmmd5c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791802507; c=relaxed/simple; bh=fFDTV4tknej5/oC553x/1wpk3lPrWmgTvW3kL2Q4fnc=; h=Message-ID:From:Subject:To:Cc:In-Reply-To:References:Content-Type: Date; b=X17Ix64ndUL7ny2949wc0dHCaGU8G7y1z9tWpQaP2X/Bv6FIetzfcRWKT1oaRMdxxbfmUZHGzq5uV3JC9rZSo8aVMKlDhlZXybcma/C8gXj3jkehPdjsj2ltDcT8ktt1jd47IzfPDhp0zXbIM/TQuUipIv1vmsfdaDbhI8iZ5i8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=M0+QAlMY; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="M0+QAlMY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 13ABD1F0089C; Mon, 12 Oct 2026 10:55:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791802506; bh=6sMxjOVVzKcbzkN9mK3nHJc2Trc0FTForDcdmKptHZY=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=M0+QAlMY9G9wtQFFzEau4A06+1NWw0Ca6vIo2hG+mCw48HQtJsGAFfkUp0LdAvIVY Riiia59FBSe7CgBEkS/s77aplPwxgu1U07qaErC6VgQSnrONIY2eluBJV14N8/Fon0 j2AG3JU1vXLcFSGYj8KZZutTiCXqc7dBdnP7E+E3qKw13w3ssaPZbw/QzE3vSSED5D /9qTzQf/qpIwXhS1ajyI+A7mGF80zX45rOWMVUuXbw4ZVUHdfNgSkC1Dk2siewckMn dOFgoAPZalcvw8lOF1m0QOotLiAMqVEMaMzMciii2ukb1p0009CndTOUm2+B3QZipa 0aGXXzshF/DNQ== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH RFC 27/28] xfs: allow remounting read-only after a shutdown Reply-To: sashiko-reviews@lists.linux.dev To: "Christian Brauner" Cc: linux-ext4@vger.kernel.org, dsterba@suse.cz, "Joseph Qi" , tytso@mit.edu, "Joel Becker" , "Mark Fasheh" In-Reply-To: <20261012-work-fs-sb_rdonly-v1-27-60743a3dc326@kernel.org> References: <20261012-work-fs-sb_rdonly-v1-0-60743a3dc326@kernel.org> <20261012-work-fs-sb_rdonly-v1-27-60743a3dc326@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 12 Oct 2026 10:55:05 +0000 Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > A shut down xfs can't be remounted read-only. xfs_remount_ro() starts > with sync_filesystem() and xfs_fs_sync_fs() fails with -EIO because the > log can't be forced anymore. So "mount -o remount,ro" fails with EIO and > the filesystem stays read-write. And emergency remount (sysrq u) asks > every read-write superblock on a block device to go read-only with > SB_FORCE. xfs refuses that too and reconfigure_super() warns before it > sets SB_RDONLY anyway: >=20 > sysrq: Emergency Remount R/O > forced remount of a xfs fs returned -5 > WARNING: fs/super.c:1133 at reconfigure_super+0x498/0xb20, CPU#0: kwork= er/0:1/11 >=20 > With panic_on_warn that's a panic from sysrq u. ext4 had the same > problem in its emergency state. >=20 > [ ... ] > echo u > /proc/sysrq-trigger # WARNING: forced remount of a xfs fs re= turned -5 >=20 > Fixes: b97cca3ba909 ("xfs: only bother with sync_filesystem during readon= ly remount") > Cc: stable@vger.kernel.org > Signed-off-by: Christian Brauner (Amutable) Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261012-work-fs-sb= _rdonly-v1-0-60743a3dc326@kernel.org?part=3D27