linux-kernel - Re: [PATCH 01/19] dax: remove block device dependencies

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200116192353.GD25291@redhat.com>
Date:   Thu, 16 Jan 2020 14:23:53 -0500
From:   Vivek Goyal <vgoyal@...hat.com>
To:     Dan Williams <dan.j.williams@...el.com>
Cc:     Jeff Moyer <jmoyer@...hat.com>, Jan Kara <jack@...e.cz>,
        "Darrick J. Wong" <darrick.wong@...cle.com>,
        Christoph Hellwig <hch@...radead.org>,
        Dave Chinner <david@...morbit.com>,
        Miklos Szeredi <miklos@...redi.hu>,
        linux-nvdimm <linux-nvdimm@...ts.01.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "Dr. David Alan Gilbert" <dgilbert@...hat.com>,
        virtio-fs@...hat.com, Stefan Hajnoczi <stefanha@...hat.com>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>
Subject: Re: [PATCH 01/19] dax: remove block device dependencies

On Thu, Jan 16, 2020 at 11:09:00AM -0800, Dan Williams wrote:

[..]
> > > True, but if kpartx + udev can make this transparent then I don't
> > > think users lose any functionality. They just gain a device-mapper
> > > dependency.
> >
> > So udev rules will trigger when a /dev/pmemX device shows up and run
> > kpartx which in turn will create dm-linear devices and device nodes
> > will show up in /dev/mapper/pmemXpY.
> >
> > IOW, /dev/pmemXpY device nodes will be gone. So if any of the scripts or
> > systemd unit files are depenent on /dev/pmemXpY, these will still be
> > broken out of the box and will have to be modified to use device nodes
> > in /dev/mapper/ directory instead. Do I understand it right, Or I missed
> > the idea completely.
> 
> No, I'd write the udev rule to create links from /dev/pmemXpY to the
> /dev/mapper device, and that rule would be gated by a new pmem device
> attribute to trigger when kpartx needs to run vs the kernel native
> partitions.

Got it. This sounds much better.

Vivek