Return-Path: linux-nfs-owner@vger.kernel.org Received: from cantor2.suse.de ([195.135.220.15]:37824 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754528AbaFLBoH (ORCPT ); Wed, 11 Jun 2014 21:44:07 -0400 Date: Thu, 12 Jun 2014 11:43:57 +1000 From: NeilBrown To: "J. Bruce Fields" Cc: Trond Myklebust , NFS Subject: Re: Live lock in silly-rename. Message-ID: <20140612114357.3a50f3ab@notabene.brown> In-Reply-To: <20140611142102.GB19382@fieldses.org> References: <20140529164521.02324559@notabene.brown> <20140530075135.753fb7ed@notabene.brown> <20140530004423.GA13746@fieldses.org> <20140530134442.5a8e5983@notabene.brown> <20140530215522.GA27615@fieldses.org> <20140531081358.62ae69b3@notabene.brown> <20140604173926.53918af3@notabene.brown> <20140604220531.GA8362@fieldses.org> <20140605103423.43e21569@notabene.brown> <20140611142102.GB19382@fieldses.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/nMq1J81jRSEAG+Bb7.2XR5J"; protocol="application/pgp-signature" Sender: linux-nfs-owner@vger.kernel.org List-ID: --Sig_/nMq1J81jRSEAG+Bb7.2XR5J Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Wed, 11 Jun 2014 10:21:02 -0400 "J. Bruce Fields" wrote: > On Thu, Jun 05, 2014 at 10:34:23AM +1000, NeilBrown wrote: > > On Wed, 4 Jun 2014 18:05:31 -0400 "J. Bruce Fields" > > wrote: > >=20 > > > On Wed, Jun 04, 2014 at 05:39:26PM +1000, NeilBrown wrote: > > > > Below is my suggestion. It seems easy enough. It even works. > > >=20 > > > Woah! > > >=20 > > > Anyway, looks reasonable to me, and it fixes an immediate problem so = I'm > > > inclined to just apply. > ... > > And if you are going to apply it, you'll want: > >=20 > > Signed-off-by: NeilBrown >=20 > Oh, gah, then I forgot to actually apply. The best laid plan of mice .... >=20 > Anyway, it's a reasonably self-contained fix for an important bug so > I'll send it as part of a later bugfix pull request. >=20 > I thought it could also use a more explicit description of the resulting > problem, so I added: >=20 > ... so further delegations should not be handed out. >=20 > The current code fails to do so, and the result is effectively a > live-lock under some workloads: a client attempting a > conflicting operation on a read-delegated file receives > NFS4ERR_DELAY and retries the operation, but by the time it > retries the server may already have given out another > delegation. Looks good, thanks. NeilBrown --Sig_/nMq1J81jRSEAG+Bb7.2XR5J Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIVAwUBU5kF3Tnsnt1WYoG5AQKUJg//d+2CTOlv1lkZ27yhMGvhY0j4wh22FGSC Vebnv9INee/yyLN5qsh3hkxauoQ/3psIq0F0dzxFS1IgnaXZ7uzY0UTlpuUhFSpZ Q/vpc45F24m+JgEVBLY21xkAAsv46+zQrzwDmyFO27jXNHJcgMF+pXEZgmMEtpkT zIe/xNeH9kSE8zPu3VL5GzFrjra5PqAOS/p/Y+akvOQNHjJC+5Cd3LAFEFiRRKQY nrhXSwgoUZXLCReBWhzKEfixZho+A7ump6s/0PDnPKMfgIWCkH+Nj+fa+ntSv4U5 suxn7gUO3fNbRjM3VrXHiJ7L/l1B5XE3hlo1B/ztNQAyFUUDEDOmPUutrjaj7lB6 ZSghDxRoUN0loAUG0M1wqdXHQ+y217nQmSmjtxidNGQyvOFfglPkgjX0e+0Eaw3M po24kTh2L0wEgTlWvkha940MDSz/lk5kerus9pfN/IxcPGS0QZaqqymUQQp9xp5R fXRKwryIoTGhDnFBKNfZiZwkqb4ZgQjwAVFnKSyhPvzAgFJku3IGJa9+9KGpoc4k /+oBjuR5sGHqzTuMejkBq6+p+zCc3UdXuFfcqrBxt8i320Qwa+3g/5w3pSolxufb k2JnTXyvMpcV5UvJ8x3S+sshv7c082qJV6NzKj45kFouBVJXDvmxIel+MV//t4RD RL4RkxA1lJI= =2hEK -----END PGP SIGNATURE----- --Sig_/nMq1J81jRSEAG+Bb7.2XR5J--