From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Eli Malul" Subject: creating a cascaded linear devices fails Date: Thu, 14 Apr 2011 12:06:26 +0300 Message-ID: Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============4766342916176957600==" Return-path: Content-class: urn:content-classes:message List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: dm-devel@redhat.com List-Id: dm-devel.ids This is a multi-part message in MIME format. --===============4766342916176957600== Content-class: urn:content-classes:message Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01CBFA83.3CA25E54" This is a multi-part message in MIME format. ------_=_NextPart_001_01CBFA83.3CA25E54 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I do not understand why creating a linear device and then trying to create another linear device on top of it fails. 1. Creating a linear device over loop1: =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D dmsetup create linear_loop1 /tmp/linear_loop1 cat /tmp/linear_loop1 0 1000 linear /dev/loop1 0 2. Then creating another linear device over this linear device: =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D dmsetup create linear_loop2 /tmp/linear_loop2 device-mapper: reload ioctl failed: Invalid argument Command failed cat /tmp/klinear_loop2 0 1000 linear /dev/linear_loop1 0 =20 Could you please explain what am I doing wrong? ------_=_NextPart_001_01CBFA83.3CA25E54 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

I do not = understand why creating a linear device and then trying to create = another linear device on top of it fails.

1.       = Creating a linear device = over = loop1:
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D
dmsetup create linear_loop1 = /tmp/linear_loop1

cat /tmp/linear_loop1
0 1000 linear = /dev/loop1 0

2.       = Then creating another = linear device over this linear = device:
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D<= br>dmsetup create linear_loop2 /tmp/linear_loop2

device-mapper: = reload ioctl failed: Invalid argument
Command failed

cat = /tmp/klinear_loop2
0 1000 linear /dev/linear_loop1 0

 

Could you = please explain what am I doing wrong?

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