Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752897Ab0GISnH (ORCPT ); Fri, 9 Jul 2010 14:43:07 -0400 Received: from idcmail-mo2no.shaw.ca ([64.59.134.9]:49040 "EHLO idcmail-mo2no.shaw.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751930Ab0GISnE convert rfc822-to-8bit (ORCPT ); Fri, 9 Jul 2010 14:43:04 -0400 X-Cloudmark-SP-Filtered: true X-Cloudmark-SP-Result: v=1.0 c=1 a=kfmJinPqzyUA:10 a=1CvaPgNKC-EA:10 a=VphdPIyG4kEA:10 a=kj9zAlcOel0A:10 a=c23vf5CSMVc0QQz9B4a6RA==:17 a=VnNF1IyMAAAA:8 a=e--v2E7seF_T0D39w2UA:9 a=O6-lKtWIugHkKau7EnbWSs-ltyEA:4 a=CjuIK1q_8ugA:10 Subject: Re: [PATCH -V14 0/11] Generic name to handle and open by handle syscalls Mime-Version: 1.0 (Apple Message framework v1078) Content-Type: text/plain; charset=us-ascii From: Andreas Dilger In-Reply-To: <20100708222121.5c0612ef@notabene.brown> Date: Fri, 9 Jul 2010 12:42:42 -0600 Cc: "Aneesh Kumar K. V" , "J. Bruce Fields" , Miklos Szeredi , Dave Chinner , Christoph Hellwig , "viro@zeniv.linux.org.uk Viro" , "corbet@lwn.net Corbet" , "hooanon05@yahoo.co.jp Okajima" , linux-fsdevel@vger.kernel.org, "sfrench@us.ibm.com French" , "philippe.deniel@CEA.FR Deniel" , "linux-kernel@vger.kernel.org Mailinglist" Content-Transfer-Encoding: 8BIT Message-Id: <5DF5C974-092B-4CE6-B11D-2DBB73782149@dilger.ca> References: <20100706161002.GD7387@fieldses.org> <87eifgfsez.fsf@linux.vnet.ibm.com> <20100706232351.GD25018@dastard> <20100707093629.10c2feab@notabene.brown> <20100707021150.GF25018@dastard> <20100707125726.3695587a@notabene.brown> <20100707125701.GA19872@fieldses.org> <20100707131721.GB19872@fieldses.org> <20100707144511.GA24360@fieldses.org> <20100708082143.3701bfc7@notabene.brown> <87wrt6dzp2.fsf@linux.vnet.ibm.com> <20100708222121.5c0612ef@notabene.brown> To: Neil Brown X-Mailer: Apple Mail (2.1078) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1037 Lines: 22 On 2010-07-08, at 06:21, Neil Brown wrote: > On Thu, 08 Jul 2010 16:10:09 +0530 > "Aneesh Kumar K. V" wrote: >> How about adding mnt_id to the handle ? Documentation file says it is unique >> >> (1) mount ID: unique identifier of the mount (may be reused after umount) But this value is not persistent across a reboot, or even an umount/mount so it is not useful as an identifier. I suppose one way to resolve this issue is to just allow the underlying filesystem to supply a completely opaque filehandle to userspace. For local filesystems that don't care about persistence or uniqueness between nodes they can use something like mount_id, and for distributed/clustered filesystems they can include a globally-unique identifier. Cheers, Andreas -- 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/