From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.90_1) id 1lsmHK-0004Mt-GE for mharc-grub-devel@gnu.org; Mon, 14 Jun 2021 09:05:26 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48668) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lsmHI-0004Gx-IK for grub-devel@gnu.org; Mon, 14 Jun 2021 09:05:20 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:45645) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lsmHF-0004BD-Qc for grub-devel@gnu.org; Mon, 14 Jun 2021 09:05:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623675916; 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: in-reply-to:in-reply-to:references:references; bh=wsFovRxM29VHpGuwn7pDRNQQ/h9V3ncM0sn+I9eX1vk=; b=jSjiCwQSYGcyL+BruEFRel8DMYS1iqadngnV9qtvTtz/UNataC91rQ86SH+j9fNwvBG3vn 1RO0oRHb36gZ9lf8RkYoOffZrJ9TY/mHf2Us17bKxNQdz4EoocXMGnpfkH28K2iAokoFIa L1ODD4LBKZxOA8QI/BnVF7FVZwX3dlA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-330-FafjO5hvNAe8ggqJDswFmA-1; Mon, 14 Jun 2021 09:03:53 -0400 X-MC-Unique: FafjO5hvNAe8ggqJDswFmA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0F6228049D0 for ; Mon, 14 Jun 2021 13:03:53 +0000 (UTC) Received: from work (unknown [10.40.192.159]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5774C5D6A8; Mon, 14 Jun 2021 13:03:45 +0000 (UTC) Date: Mon, 14 Jun 2021 15:03:41 +0200 From: Lukas Czerner To: Javier Martinez Canillas Cc: grub-devel@gnu.org, Eric Sandeen , Colin Walters , Dusty Mabe , Jonathan Lebon , Peter Jones Subject: Re: [PATCH] fs/ext2: Ignore checksum seed incompat feature support Message-ID: <20210614130341.fpxkhgqnx7v7wfwv@work> References: <20210611193616.2596290-1-javierm@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210611193616.2596290-1-javierm@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=lczerner@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=lczerner@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.2, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 14 Jun 2021 13:05:20 -0000 On Fri, Jun 11, 2021 at 09:36:16PM +0200, Javier Martinez Canillas wrote: > This incompat feature is used to denote that the filesystem stored its > metadata checksum seed in the superblock. This is used to allow tune2fs > to change the UUID on a mounted metadata_csum filesystem without having > to rewrite all the disk metadata. > > But GRUB doesn't use the metadata checksum in anyway, so can just ignore > this feature if is enabled. This is consistent with GRUB filesystem code > in general which just does a best effort to access the filesystem's data. > > It may be removed from the ignored list in the future if supports to do > metadata checksumming verification is added to the read-only FS driver. Thanks, you can add Reviewed-by: Lukas Czerner -Lukas > > Suggested-by: Eric Sandeen > Suggested-by: Lukas Czerner > Signed-off-by: Javier Martinez Canillas > --- > > grub-core/fs/ext2.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/grub-core/fs/ext2.c b/grub-core/fs/ext2.c > index 848bf939dba..238b2d76e38 100644 > --- a/grub-core/fs/ext2.c > +++ b/grub-core/fs/ext2.c > @@ -103,6 +103,7 @@ GRUB_MOD_LICENSE ("GPLv3+"); > #define EXT4_FEATURE_INCOMPAT_64BIT 0x0080 > #define EXT4_FEATURE_INCOMPAT_MMP 0x0100 > #define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200 > +#define EXT4_FEATURE_INCOMPAT_CSUM_SEED 0x2000 > #define EXT4_FEATURE_INCOMPAT_ENCRYPT 0x10000 > > /* The set of back-incompatible features this driver DOES support. Add (OR) > @@ -123,9 +124,16 @@ GRUB_MOD_LICENSE ("GPLv3+"); > * mmp: Not really back-incompatible - was added as such to > * avoid multiple read-write mounts. Safe to ignore for this > * RO driver. > + * checksum seed: Not really back-incompatible - was added to allow tools > + * such as tune2fs to change the UUID on a mounted metadata > + * checksummed filesystem. Safe to ignore for now since the > + * driver doesn't support checksum verification. But it must > + * be removed from this list if that support is added later. > + * > */ > #define EXT2_DRIVER_IGNORED_INCOMPAT ( EXT3_FEATURE_INCOMPAT_RECOVER \ > - | EXT4_FEATURE_INCOMPAT_MMP) > + | EXT4_FEATURE_INCOMPAT_MMP \ > + | EXT4_FEATURE_INCOMPAT_CSUM_SEED) > > > #define EXT3_JOURNAL_MAGIC_NUMBER 0xc03b3998U > -- > 2.31.1 >