From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Hudec Subject: Re: filesystem transactions API Date: Wed, 27 Apr 2005 11:14:03 +0200 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" Cc: Jamie Lokier , Trond Myklebust , John Stoffel , Ville Herva , Linux Filesystem Development , linux-kernel@vger.kernel.org Return-path: 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 To: "Artem B. Bityuckiy" Content-Disposition: inline In-Reply-To: <426E65E9.5070306@oktetlabs.ru> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org --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--