From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp1040.oracle.com ([141.146.126.69]:41536 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756559AbdD1F5N (ORCPT ); Fri, 28 Apr 2017 01:57:13 -0400 Date: Thu, 27 Apr 2017 22:56:58 -0700 From: "Darrick J. Wong" Subject: Re: [PATCH] xfs: publish UUID in struct super_block Message-ID: <20170428055658.GD22884@birch.djwong.org> References: <1493279911-2936-1-git-send-email-amir73il@gmail.com> <20170427193118.GH23371@birch.djwong.org> <984c6ee4-9ece-7424-420f-1fc26faca378@sandeen.net> <20170428054945.rg54cm5yftfuqfsf@brain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170428054945.rg54cm5yftfuqfsf@brain> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Andy Whitcroft Cc: Eric Sandeen , Amir Goldstein , Christoph Hellwig , Miklos Szeredi , Vivek Goyal , Al Viro , linux-xfs@vger.kernel.org, linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org On Fri, Apr 28, 2017 at 06:49:45AM +0100, Andy Whitcroft wrote: > On Thu, Apr 27, 2017 at 03:30:35PM -0500, Eric Sandeen wrote: > > > It'd be trivial to make that a vfs function and set a flag on the vfs super > > if the UUID is not unique. Would that be worthwhile? I can send a patch > > if so. > > This only tells you that the UUID it has is unique now. As you are > contemplating storing them in the FS they have to be unique in space > _and_ time. No check you can do now can tell you if the UUID is unique > for all time. Right ? Well, since we're talking about all time: "probably" :P That said, Eric was talking about a refactoring of one of XFS's mount time checks that errors out if there's already a mounted fs with the same uuid. We use it to avoid catastrophic mounting of the same fs from multiple (misconfigured) multipaths/snapshots/volumes/whatever on the same machine. Not sure if that's useful for Amir's case. --D > > -apw > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html