From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: linux-nfs-owner@vger.kernel.org Received: from cantor2.suse.de ([195.135.220.15]:56867 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750702AbaGJFLS (ORCPT ); Thu, 10 Jul 2014 01:11:18 -0400 Date: Thu, 10 Jul 2014 15:11:12 +1000 From: NeilBrown To: Nathan Shearer Cc: linux-nfs@vger.kernel.org Subject: Re: umount -f stalls forever Message-ID: <20140710151112.7710bb7b@notabene.brown> In-Reply-To: <53BDA2C7.4030007@nathanshearer.ca> References: <53BDA2C7.4030007@nathanshearer.ca> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/Z9XLYwSFP15WBzk8k4Nt3kg"; protocol="application/pgp-signature" Sender: linux-nfs-owner@vger.kernel.org List-ID: --Sig_/Z9XLYwSFP15WBzk8k4Nt3kg Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Wed, 09 Jul 2014 14:15:03 -0600 Nathan Shearer wrote: > When I have an nfs share that is mounted with the hard option (either > explicitly or implicitly since hard is on by default), and the nfs > server becomes unresponsive for any reason, it often causes the entire > OS to hang on many operations. In some cases I cannot even reboot a > server depending on what the nfs share was used for. >=20 > I relaize that this was probably done intentionally to prevent data > loss. However, when I am cleaning up a disaster and I actually do want > to "umount -f" a stalled nfs share and data loss es acceptable, then I > expect that command to return and the share to be unmounted. From a > usability perspective, stalling forever when I am explicitly forcing an > action is not right. >=20 > There is a workaround: and that is to assign the IP of the nfs server to > my system then issue umount -f, however that hardly the best way since I > am changing my network topology to unmount an offline filesystem. In > some situations adding an IP to an interface is not possilble, and if > the system is a remote system it could lead to more problems since it is > mostly unresponsive. >=20 > It would be greatly appreciated if a patch could be introduced that > allows "umount -f" to actually work without making any other changes to > a running system. The man page for umount even states that the -f > argument can be used to unmount an unreachable nfs share -- but it > almost never works. > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html Hi Nathan, you don't say what kernel you are running.... A change was made in Linux 3.12 (8033426e6bdb2690d302872ac1e1fadaec1a5581) which may address the problem you have. So if you are using a kernel older than that, try a newer kernel. This may not make "umount -f" work, but it should stop it from hanging. To make it work you might need to kill all the processes using the mount point first. Also, "umount -l" might be a suitable answer to your problems. NeilBrown --Sig_/Z9XLYwSFP15WBzk8k4Nt3kg Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIVAwUBU74gcDnsnt1WYoG5AQI7bw//aGQ47g4bStBCW1OJmBuWhRzKTa7W9VBb P7kUA3NSVdpWyCwyAoAdk18I4zrOEhNNPNm0apY4sLDyGVGlVOi9WCVhedQF3qs4 rZYY0dqfD2ErpCr6kmpJKUdNKWAtsNLSNUtV+KqDkZ++exVIiSwstD7yfKPKmhey 0bQP7tuWn2Do97pogAiZ7pr89RJKBi9Om6h5rmRf6V5mT+uXyyK5BMcX7Nf+VOyN ay2OYtuBNT9TnFXYyKvwXz+kCrFTI0hx7QtDm+EIkOYw1v23v9DhqsKP5SS+e4+M ceOUQLa88+orE1BHEAubchnfK2gUdaFoENPKsbwSebrVcMnZg+ZL4ieO74ikmpJo ghLo6fAZ1tI8PhFr+wT1vlYLpafeCyd3uRQRfD7w6q0Az/gjl9qJEqPQs32t+YRl uTACqg1oY4Q8C/ygxMmIjt70jeuRuehfNvbAWVP0R0WBf2qrIgpyW/L5KjTOtczL iAKOKzla/64pw8nz6kea6e0sMBD8wwXjCEAE/uYnBExTYF96hpMSCVrvo2ZNCz5U /RaZrOK+Qumub0/r8ODmEh6rTtgRN1Rye6hkcpnV3NIYpszxBHIW8P8RiBWO8LnJ ls1c7hE6a1ZuH2HktzmusiTwr2FCvczsH+SV27wNsoZWdDTN6IEAdJ38sNiG5XNw OzpMy12b/UA= =Lc9Z -----END PGP SIGNATURE----- --Sig_/Z9XLYwSFP15WBzk8k4Nt3kg--