Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757480Ab2EJIeG (ORCPT ); Thu, 10 May 2012 04:34:06 -0400 Received: from a.ns.miles-group.at ([95.130.255.143]:47834 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757376Ab2EJIeB (ORCPT ); Thu, 10 May 2012 04:34:01 -0400 Message-ID: <4FAB7D70.1040704@nod.at> Date: Thu, 10 May 2012 10:33:52 +0200 From: Richard Weinberger User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:8.0) Gecko/20111105 Thunderbird/8.0 MIME-Version: 1.0 To: dedekind1@gmail.com CC: linux-mtd@lists.infradead.org, tim.bird@am.sony.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, Heinz.Egger@linutronix.de Subject: Re: [RFC v2] UBI: UBIVIS (aka checkpointing) support References: <1336585125-127220-1-git-send-email-richard@nod.at> <1336624000.1936.22.camel@brekeke> In-Reply-To: <1336624000.1936.22.camel@brekeke> X-Enigmail-Version: 1.3.4 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig4A472D14821CF0BDA8640FA7" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3249 Lines: 89 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig4A472D14821CF0BDA8640FA7 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi Artem! Am 10.05.2012 06:26, schrieb Artem Bityutskiy: > Hi Richard, I would like to complain about the names again. I though I > better give this feed back as soon as possible... No problem. :) > Firs of all, thanks for doing this, I will look closer, and I am very > keen of merging this stuff once we are sure its design is good, allows > for future extensions and is backward-compatible. >=20 Yeah. First of all, yes it's fully backward-compatible. It uses two new interna= l volume IDs with compat =3D UBI_COMPAT_DELETE. Old UBI implementations will delete the checkpoint and continue with scan= ning... Regarding design, ubi_wl_get_peb() currently offers three types of data t= ypes. UBI_LONGTERM, UBI_SHORTTERM and UBI_UNKNOWN. Do we really need them? Checkpointing has a pool of unknown PEBs. This PEBs have to be scanned wh= ile attaching. For now I had to create three pools (for UBI_LONGTERM, UBI_SHORTTERM and = UBI_UNKNOWN). This makes the whole thing complexer than needed. It introduces also some nasty corner cases. To make the review easier for you: The most critical code path is scan_pool() -> process_pool_seb() -> updat= e_vol(). It searches within a pool for PEBs which are no longer empty and scans th= em. After that it updates the corresponding volume. ubi_update_checkpoint() is also very important because it has to find unused PEBs at the beginning of the MTD to place the super block. > So may be just naming your stuff UBI2, having terms like "UBI2 format",= > would be the easiest? Then someone could make this to be UBI3. A > documentation section could describe what UBI2 is and how it is > different from UBI1 or just UBI. Okay, got your point. I think "fastmap" is a good name because I can also use it within the cod= e. So, while reviewing the code please keep s/checkpoint/fastmap/g and s/cp/= fm/g in mind. ;-) I like the UBI2 idea. UBI2 =3D UBI + fastmap. After the UBI2/fastmap design is stable I will happily write a detailed d= esign paper for http://www.linux-mtd.infradead.org/doc/ubi.html. Thanks, //richard --------------enig4A472D14821CF0BDA8640FA7 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iQEcBAEBAgAGBQJPq310AAoJEN9758yqZn9eJnUH/iPEVCRsCCbajySwTx1bc8Sq /m1474PrumjB9LzCePlAWlixsQkBf9YsSvDInexHuQWQFc9YS8LbVG/E51qVZM+y nX6aoS9aVkmKSxtLxm9VAYDJ2VPOP3EO7a0Tlsf7qaA74RdCz8TISUEXdUjCiKRK YpfylfuZE3bKTRHHp79/8KyotfiUv1QefDLGl9AsjBhka9kbB/4X0EY3t9YZan/N anqMGbDss8I1ckPXp1Y1MBPZ3pOO+qqi7zMPrGNMciEFHIHMitxry+COzj5slX2+ ZPKM7HL5Wtyz590yePaLjIjYNfdLRqrYFD46BZNK/0TmEaOw/9T2hX3ruOYrmHE= =7lwM -----END PGP SIGNATURE----- --------------enig4A472D14821CF0BDA8640FA7-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/