Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261300AbVD0JPY (ORCPT ); Wed, 27 Apr 2005 05:15:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261307AbVD0JPY (ORCPT ); Wed, 27 Apr 2005 05:15:24 -0400 Received: from cimice4.lam.cz ([212.71.168.94]:26037 "EHLO vagabond.light.src") by vger.kernel.org with ESMTP id S261299AbVD0JPC (ORCPT ); Wed, 27 Apr 2005 05:15:02 -0400 Date: Wed, 27 Apr 2005 11:14:03 +0200 From: Jan Hudec To: "Artem B. Bityuckiy" Cc: Jamie Lokier , Trond Myklebust , John Stoffel , Ville Herva , Linux Filesystem Development , linux-kernel@vger.kernel.org Subject: Re: filesystem transactions API Message-ID: <20050427091402.GA1904@vagabond> References: <20050426134629.GU16169@viasys.com> <20050426141426.GC10833@mail.shareable.org> <426E4EBD.6070104@oktetlabs.ru> <20050426143247.GF10833@mail.shareable.org> <17006.22498.394169.98413@smtp.charter.net> <1114528782.13568.8.camel@lade.trondhjem.org> <20050426154708.GC14297@mail.shareable.org> <426E638B.9070704@oktetlabs.ru> <20050426155615.GE14297@mail.shareable.org> <426E65E9.5070306@oktetlabs.ru> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="tThc/1wpZn/ma/RB" Content-Disposition: inline In-Reply-To: <426E65E9.5070306@oktetlabs.ru> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1715 Lines: 49 --tThc/1wpZn/ma/RB Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Apr 26, 2005 at 20:01:45 +0400, Artem B. Bityuckiy wrote: > Jamie Lokier wrote: > >No. Why would you block? You can have transactions without blocking > >other processes. > > > >When updating, say, the core-utils package (which contains cat), > >there's no reason why a program which executes "cat" should have to > >block during the update. It can simply execute the old one until the > >new one is committed at the end of the update. > > > >It's analogous to RCU for protecting kernel data structures without > >blocking readers. > > > Hmm, can't we implement a user-space locking system which admits of=20 > readers during transactions? I gues we can. The problem with implementing in userland, as was already said in the thread, is, that if some process does not use the library, it can completely mess it up. It is only safe in kernel. ---------------------------------------------------------------------------= ---- Jan 'Bulb' Hudec --tThc/1wpZn/ma/RB Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (GNU/Linux) iD8DBQFCb1faRel1vVwhjGURAuKzAKDAn6YyOhPAPFTexM9OyFkwfPv46QCfWezt b7y7zyxeuOakqmo0xCN2+ik= =bnoE -----END PGP SIGNATURE----- --tThc/1wpZn/ma/RB-- - 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/