From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: dm: Get devices using name_to_dev_t Date: Wed, 14 Jan 2015 21:26:36 -0500 Message-ID: <20150115022636.GA7967@redhat.com> References: <1421280960-23984-1-git-send-email-dehrenberg@chromium.org> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1421280960-23984-1-git-send-email-dehrenberg@chromium.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Dan Ehrenberg Cc: grundler@chromium.org, drewry@chromium.org, dm-devel@redhat.com, gwendal@chromium.org List-Id: dm-devel.ids On Wed, Jan 14 2015 at 7:16pm -0500, Dan Ehrenberg wrote: > If a device is used as the root filesystem, it can't be built > off of devices which are within the root filesystem (just like > command line arguments to root=). For this reason, Linux has a > pseudo-filesystem for root= and md initialization based on the > function name_to_dev_t, which handles different ways of specifying > devices including PARTUUID and major:minor. > > This patch applies name_to_dev_t to dm initialization. Rather > than assuming that all things which are not major:minor are paths > in an already-mounted filesystem, this patch first attempts > name_to_dev_t and tries the filesystem as a fallback. What is all this talk of an already-mounted filesystem? dm_get_device() currently assumes either a major:minor or path to the block device is provided. Please be specific about what functionality this change enables that you cannot do without.