From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from prime.voidband.net (prime.voidband.net [199.247.17.104]) (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 4D0C525F78F; Mon, 13 Oct 2025 19:18:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=199.247.17.104 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760383114; cv=none; b=QzCe9OO4M9CVM2b/yavvb+vT7BoMWA0ITAmnIQR0B8RtC3Mgy3UsVoE2Tm8/GoG3/738n+Sqx1ACChHSl7UnoV+RpK1TQ8qHiHaNMIKNCZavg4CekVfAiGK9WrQtWTPU9jtRdbtgCYQa+pGRmj5gPGlxYoV0WIE7EluLZIxpH60= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760383114; c=relaxed/simple; bh=YAr0GnSopKj79+L6J6LlxDhhP7XeesQLCHrPk01uctQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=TjhB8XAPKXRwU1h5SwCAlAjnCrv62FHZG5hK4pPy4BsiPIjU5L56OqshWc3oahR8xWMPCw6UFEd+oSWKc1v1Xckm7N8zCZaNtqLIQyOMBgtGSAKRBfx3v/ZiqrLOBEja4yhAU91Xw5NhiP9hdhSvU2xDO4z7um3l4VQjeJIBElI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=natalenko.name; spf=pass smtp.mailfrom=natalenko.name; dkim=pass (1024-bit key) header.d=natalenko.name header.i=@natalenko.name header.b=wyy1/gyJ; arc=none smtp.client-ip=199.247.17.104 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=natalenko.name Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=natalenko.name Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=natalenko.name header.i=@natalenko.name header.b="wyy1/gyJ" Received: from spock.localnet (unknown [212.20.115.26]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by prime.voidband.net (Postfix) with ESMTPSA id 79A14635B045; Mon, 13 Oct 2025 21:08:52 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=natalenko.name; s=dkim-20170712; t=1760382532; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type; bh=hWDaP/sYXgodO6ibobWEGOJClFcvhDTYB+sevTJgK0c=; b=wyy1/gyJnBoGR03czEQ5VwChqIRVliMbmOjJi9fwIPDbu61fQ6cX7tBAEyXazrDULGIEEz vT0u7oTAlwmM20/eVI29XIrHiEVAxOzSbMbqxfLmClpzmjG0T2iA1DzU1ftfXRGsNHMTHn 4yeKHhUTC23NHHB/bJo7K7ONpD0mWzM= From: Oleksandr Natalenko To: linux-kernel@vger.kernel.org Cc: linux-xfs@vger.kernel.org, Carlos Maiolino , "Darrick J. Wong" , Pavel Reichl , Vlastimil Babka , Thorsten Leemhuis Subject: XFS attr2 mount option removal may break system boot Date: Mon, 13 Oct 2025 21:08:38 +0200 Message-ID: <3654080.iIbC2pHGDl@natalenko.name> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart9517416.CDJkKcVGEf"; micalg="pgp-sha512"; protocol="application/pgp-signature" --nextPart9517416.CDJkKcVGEf Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8"; protected-headers="v1" From: Oleksandr Natalenko To: linux-kernel@vger.kernel.org Subject: XFS attr2 mount option removal may break system boot Date: Mon, 13 Oct 2025 21:08:38 +0200 Message-ID: <3654080.iIbC2pHGDl@natalenko.name> MIME-Version: 1.0 Hello. In v6.18, the attr2 XFS mount option is removed. This may silently break system boot if the attr2 option is still present in /etc/fstab for rootfs. Consider Arch Linux that is being set up from scratch with / being formatted as XFS. The genfstab command that is used to generate /etc/fstab produces something like this by default: /dev/sda2 on / type xfs (rw,relatime,attr2,discard,inode64,logbufs=8,logbsize=32k,noquota) Once the system is set up and rebooted, there's no deprecation warning seen in the kernel log: # cat /proc/cmdline root=UUID=77b42de2-397e-47ee-a1ef-4dfd430e47e9 rootflags=discard rd.luks.options=discard quiet # dmesg | grep -i xfs [ 2.409818] SGI XFS with ACLs, security attributes, realtime, scrub, repair, quota, no debug enabled [ 2.415341] XFS (sda2): Mounting V5 Filesystem 77b42de2-397e-47ee-a1ef-4dfd430e47e9 [ 2.442546] XFS (sda2): Ending clean mount Although as per the deprecation intention, it should be there. Vlastimil (in Cc) suggests this is because xfs_fs_warn_deprecated() doesn't produce any warning by design if the XFS FS is set to be rootfs and gets remounted read-write during boot. This imposes two problems: 1) a user doesn't see the deprecation warning; and 2) with v6.18 kernel, the read-write remount fails because of unknown attr2 option rendering system unusable: systemd[1]: Switching root. systemd-remount-fs[225]: /usr/bin/mount for / exited with exit status 32. # mount -o rw / mount: /: fsconfig() failed: xfs: Unknown parameter 'attr2'. Thorsten (in Cc) suggested reporting this as a user-visible regression. >From my PoV, although the deprecation is in place for 5 years already, it may not be visible enough as the warning is not emitted for rootfs. Considering the amount of systems set up with XFS on /, this may impose a mass problem for users. Vlastimil suggested making attr2 option a complete noop instead of removing it. Please check. Thank you. -- Oleksandr Natalenko, MSE --nextPart9517416.CDJkKcVGEf Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. 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