From owner-freebsd-virtualization@FreeBSD.ORG  Fri Oct  3 01:38:49 2014
Return-Path: <owner-freebsd-virtualization@FreeBSD.ORG>
Delivered-To: freebsd-virtualization@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id A6EB5AFF
 for <freebsd-virtualization@freebsd.org>; Fri,  3 Oct 2014 01:38:49 +0000 (UTC)
Received: from borg.macktronics.com (borg.macktronics.com [209.181.253.68])
 by mx1.freebsd.org (Postfix) with ESMTP id 85B2BF1B
 for <freebsd-virtualization@freebsd.org>; Fri,  3 Oct 2014 01:38:49 +0000 (UTC)
Received: from olive.macktronics.com (olive.macktronics.com [209.181.253.67])
 by borg.macktronics.com (Postfix) with ESMTP id A91EA7D4
 for <freebsd-virtualization@freebsd.org>; Thu,  2 Oct 2014 20:32:04 -0500 (CDT)
Date: Thu, 2 Oct 2014 20:32:04 -0500 (CDT)
From: Dan Mack <mack@macktronics.com>
To: freebsd-virtualization@freebsd.org
Subject: virtio_blk devices on linux and FL_CD ?
Message-ID: <alpine.BSF.2.11.1410022023490.7190@olive.macktronics.com>
User-Agent: Alpine 2.11 (BSF 23 2013-08-11)
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII
X-BeenThere: freebsd-virtualization@freebsd.org
X-Mailman-Version: 2.1.18-1
Precedence: list
List-Id: "Discussion of various virtualization techniques FreeBSD supports."
 <freebsd-virtualization.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-virtualization>, 
 <mailto:freebsd-virtualization-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-virtualization/>
List-Post: <mailto:freebsd-virtualization@freebsd.org>
List-Help: <mailto:freebsd-virtualization-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization>, 
 <mailto:freebsd-virtualization-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 03 Oct 2014 01:38:49 -0000


Anyone know why sda doesn't have the FL_CD bit set but vda (virtio_blk) devices do ?

I just came across this when working through a disk enumerator for an
OS install when running my tests under bhyve and was curious.

The linux genhd.h file isn't super clear as to what GEN_FL_CD means
but I think it is CDROM ???

  #define GENHD_FL_REMOVABLE                      1
  /* 2 is unused */
  #define GENHD_FL_MEDIA_CHANGE_NOTIFY            4
  #define GENHD_FL_CD                             8
  #define GENHD_FL_UP                             16
  #define GENHD_FL_SUPPRESS_PARTITION_INFO        32
  #define GENHD_FL_EXT_DEVT                       64 /* allow extended devt */
  #define GENHD_FL_NATIVE_CAPACITY                128
  #define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE     256
  #define GENHD_FL_NO_PART_SCAN                   512

or does it mean character device ?

On a bhyve Linux system I see this for example:

[root@cent ~]# ./diskcapability.bash
sr0  (cap == 119)
  |  REMOVABLE
  |  MEDIA_CHANGE_NOTIFY
  |  UP
  |  SUPPRESS_PARTITION_INFO
  |  EXT_DEVT
vda  (cap == 10)
  |  CD

I don't think this has anything to do with bhyve becuase the same
thing happens on a digital ocean coreos system.

The linux header file says '2' is unused but it appears to be set, no?  10==8+2

dan
--
Dan Mack