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( [213.37.137.93]) by mx.google.com with ESMTPS id 27sm4387323ugp.82.2008.07.01.16.28.33 (version=SSLv3 cipher=RC4-MD5); Tue, 01 Jul 2008 16:28:34 -0700 (PDT) From: Javier =?ISO-8859-1?Q?Mart=EDn?= To: The development of GRUB 2 In-Reply-To: <20080701204816.GA31206@thorin> References: <1214769230.6942.11.camel@localhost> <20080629211957.GD24784@thorin> <1214794971.9353.32.camel@localhost> <4868C017.8040004@isaac.cedarswampstudios.org> <1214827937.9353.43.camel@localhost> <20080701160827.GF6985@thorin> <1214929545.13432.19.camel@dv> <1214937759.9353.64.camel@localhost> <20080701204816.GA31206@thorin> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-sVggOL0maYuOU6kg8JkG" Date: Wed, 02 Jul 2008 01:28:47 +0200 Message-Id: <1214954927.9353.91.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.22.2 X-detected-kernel: by monty-python.gnu.org: Linux 2.6 (newer, 2) Subject: Re: grub-probe detects ext4 wronly as ext2 X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: The development of GRUB 2 List-Id: The development of GRUB 2 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 01 Jul 2008 23:28:37 -0000 --=-sVggOL0maYuOU6kg8JkG Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable El mar, 01-07-2008 a las 22:48 +0200, Robert Millan escribi=C3=B3: > On Tue, Jul 01, 2008 at 08:42:39PM +0200, Javier Mart=C3=ADn wrote: > > partition as "unrecognized" and then I had to specifically request it t= o > > be mounted as ext2 with a possible --ignore-incompatible flag, >=20 > A --ignore-incompatible flag doesn't sound like a nice thing to do; it m= eans > we're passing our own problem to the user instead of solving it. We don't have any "problem" to pass to users: ext4 is not supported and thus we do the Right Thing (tm) in patching our ext2 driver so that it won't try to read a filesystem it cannot. However, given Pavel's and others' objections, I suggested the addition of an user override to it. Thus, the user will have to knowingly force the system to interpret the filesystem with its current code, and accept any failures he might get, instead of the current behaviour of having the FS mounted automatically without checking incompatibilities (and then getting the errors anyway). Furthermore, the possibility of accidentally adding an incompatible feature is not exactly high: for an ext3 FS to get one of the ext4 flags, one has to explicitly mount it as "ext4dev" (usually installing or hand-compiling the module before, because most distros don't include it by default) _and_ create new files on it. Then and only then will the FS gain the extents flag. >=20 > Though, if non-essential stuff needs to be implemented, please take into > account that we're really pressed for space in ext2.mod (and try to use a > separate module for that). >=20 The proposal (a patch which is essentially under ten lines of code long) could _avoid_ the implementation of format compatibility checks in all the inode-handling functions, since after passing the compatibility check we know the format we'll encounter is at least ro-compatible with our capabilities, or the user is braced for the possible errors. With the current implementation, an unawares user could be flooded by inode format errors becase, for example, an ext4 FS got mounted by our ext2 driver. The override proposal is not implemented in the current patch, but it could be as simple as an environment variable. Consider this case, with (hd0,1) an ext3 /boot partition that was accidentally converted to ext4 and then got a file copied to it (the 2.6.26-rc2 kernel), then gaining the extents flag: grub> ls (hd0,1)/ error: unrecognized filesystem grub> set ext2_options=3Dignore_incompatible grub> ls (hd0,1)/ kernel-2.6.24-r1 kernel-2.6.26-rc2 grub> kernel (hd0,1)/kernel-2.6.26-rc2 root=3D/dev/sda5 error: file not found # (I dunno what error "bad inode" is) grub> kernel (hd0,1)/kernel-2.6.24 root=3D/dev/sda5 [Linux-bzimage, 0x100000] grub> boot --=-sVggOL0maYuOU6kg8JkG Content-Type: application/pgp-signature; name=signature.asc Content-Description: Esta parte del mensaje =?ISO-8859-1?Q?est=E1?= firmada digitalmente -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iQIVAwUASGq9rqSl+Fbdeo72AQLo9hAAl1qNqvjhqFFQ9WG23gE8RcbhbCLtczBC eyxfmQhwQXuDC0dLxZdEt5YfCqfjv9vu8TW+o/fIyCBvbl9BibeG5PEvH2wf9l9D L86TfoBSoVJBjL7hqlWrWNOUe1xJq5fwKPHS0UTKhvUtVHWSJx/btuPT5xlbziu4 jKyMIZmJu+zFRhDtzDDUqo0nNmClZSjXbCX2z6rT5nATXvv04nr/px9/y0rFt66G c6PuJCaBlT497N6Mn7Vn6r7KXtHwc+CBjoKTYzmUk8UyqPU12iCFZLPAtuw4poKo lNZeMUw8grxOk4TSKtB4zpX+8ysXvJq6aIl0gNFi/biqDBO5e9CPhOXC0O1FrnpN lU0zkzuwRLFY2XRwqDkV4LsZtmgNOFQhr5avdIOoBLeu2vTU1iyVBfIFhjJIDwCj PhsODEfKRia6fKqYAQaOp4EoIKCYT9OSN8Hp3ZDPISXHS3+WCh1k23qB+oX6kUiF R4POZI+Tbo87l9ED2QDPhPLG2ttB9SnCi0G3aLZX0IgAIfOotX0HJ7LSfRpTJ2nS eNk6D2UqXBaJyU4AF8OoYcAISxXpmA2jgbKvqiVFSJEjbSH3uMKIGuMXU/gkVy8r FECV+EA+VeFDT+n+XPJ3l2Ih0nWrkmMZhyHfGPqwB8gFeDyqjP2HrmFjkIS2+OAw MyV041YxYn0= =uCLg -----END PGP SIGNATURE----- --=-sVggOL0maYuOU6kg8JkG--