From mboxrd@z Thu Jan 1 00:00:00 1970 From: Loic Dachary Subject: crc32 for erasure code Date: Mon, 23 Sep 2013 10:34:35 +0200 Message-ID: <523FFD1B.4030801@dachary.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig0D6E65A0E32A6A10A0BB809C" Return-path: Received: from smtp.dmail.dachary.org ([91.121.254.229]:42433 "EHLO smtp.dmail.dachary.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753224Ab3IWIor (ORCPT ); Mon, 23 Sep 2013 04:44:47 -0400 Received: from [10.9.0.6] (openvpn.novalocal [10.145.3.13]) by smtp.dmail.dachary.org (Postfix) with ESMTPS id 741D426395 for ; Mon, 23 Sep 2013 10:44:44 +0200 (CEST) Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Ceph Development This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig0D6E65A0E32A6A10A0BB809C Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi, Unless I'm mistaken, ceph_crc32() is currently used in master via the crc= 32c() method of bufferlist to: * encode_with_checksum/decode_with_checksum a PGLog entry * Message::decode_message/Message::encode_message a message via calc_*_cr= c=20 * FileJournal::do_read_entry/FileJournal::prepare_single_write a journal = entry * for information in the report monitory command ( Monitor.cc ) Erasure coded chunks ( i.e. files ) will need checksums. Should this be i= mplemented as an optional feature in ceph/src/os/FileStore.{h,cc} ? If th= e underlying filesystem does not provide this feature, FileStore would ca= ll ceph_crc32 each time the object is modified. A verification method wou= ld be exposed and used when scrubbing erasure coded pools. Cheers --=20 Lo=EFc Dachary, Artisan Logiciel Libre All that is necessary for the triumph of evil is that good people do noth= ing. --------------enig0D6E65A0E32A6A10A0BB809C Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) Comment: Using GnuPG with undefined - http://www.enigmail.net/ iEYEARECAAYFAlI//RsACgkQ8dLMyEl6F23aCACgti0q5nyD5XZu6DUjknEq63QT sRcAn1ixLMq/Fk+ox8W1lu4e7gleOHdr =IJz0 -----END PGP SIGNATURE----- --------------enig0D6E65A0E32A6A10A0BB809C--