Libvirt provides a portable, long term stable C API for managing the virtualization technologies provided by many operating systems. It includes support for QEMU, KVM, Xen, LXC, bhyve, Virtuozzo, VMware vCenter and ESX, VMware Desktop, Hyper-V, VirtualBox and the POWER Hypervisor.
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John Ferlan e0e290552b disk: Disallow duplicated target 'dev' values
https://bugzilla.redhat.com/show_bug.cgi?id=1142631

This patch resolves a situation where the same "<target dev='$name'...>"
can be used for multiple disks in the domain.

While the $name is "mostly" advisory regarding the expected order that
the disk is added to the domain and not guaranteed to map to the device
name in the guest OS, it still should be unique enough such that other
domblk* type operations can be performed.

Without the patch, the domblklist will list the same Target twice:

$ virsh domblklist $dom
Target     Source
------------------------------------------------
sda        /var/lib/libvirt/images/file.qcow2
sda        /var/lib/libvirt/images/file.img

Additionally, getting domblkstat, domblkerror, domblkinfo, and other block*
type calls will not be able to reference the second target.

Fortunately, hotplug disallows adding a "third" sda value:

$ qemu-img create -f raw /var/lib/libvirt/images/file2.img 10M
$ virsh attach-disk $dom /var/lib/libvirt/images/file2.img sda
error: Failed to attach disk
error: operation failed: target sda already exists

$

BUT, it since 'sdb' doesn't exist one would get the following on the same
hotplug attempt, but changing to use 'sdb' instead of 'sda'

$ virsh attach-disk $dom /var/lib/libvirt/images/file2.img sdb
error: Failed to attach disk
error: internal error: unable to execute QEMU command 'device_add': Duplicate ID 'scsi0-0-1' for device

$

Since we cannot fix this issue at parsing time, the best that can be done so
as to not "lose" a domain is to make the check prior to starting the guest
with the results as follows:

$ virsh start $dom
error: Failed to start domain $dom
error: XML error: target 'sda' duplicated for disk sources '/var/lib/libvirt/images/file.qcow2' and '/var/lib/libvirt/images/file.img'

$

Running 'make check' found a few more instances in the tests where this
duplicated target dev value was being used. These also exhibited some
duplicated 'id=' values (negating the uniqueness argument of aliases) in
the corresponding .args file and of course the *xmlout version of a few
input XML files.
2015-03-02 22:38:36 -05:00
.gnulib@c27f1a356f maint: update to latest gnulib 2015-01-05 16:38:50 -07:00
build-aux bracket-spacing: Add syntax-check for unnecessary curly brackets 2014-11-14 17:13:36 +01:00
daemon daemon: Fix segfault by reloading daemon right after start 2015-02-18 17:51:54 +01:00
docs docs: add a note that attr 'managed' is only used by PCI devices 2015-03-02 10:47:06 +01:00
examples Grant access to helpers 2015-01-23 11:12:44 +01:00
gnulib maint: fix date in local gnulib patch 2015-01-05 16:44:10 +00:00
include Add VIR_CONNECT_BASELINE_CPU_MIGRATABLE flag 2015-03-02 07:59:12 +01:00
m4 Conditionalize use of -Wno-suggest-attribute=format pragma 2015-01-16 17:12:27 +00:00
po Release of libvirt-1.2.13 2015-03-02 11:40:05 +08:00
src disk: Disallow duplicated target 'dev' values 2015-03-02 22:38:36 -05:00
tests disk: Disallow duplicated target 'dev' values 2015-03-02 22:38:36 -05:00
tools virsh: Adjust domblklist to understand disk volume syntax 2015-03-02 17:07:55 -05:00
.ctags maint: Make ctags work out of the box 2013-07-18 08:47:21 +02:00
.dir-locals.el build: avoid tabs that failed syntax-check 2012-09-06 09:43:46 -06:00
.gitignore Revert "src/xenconfig: Xen-xl parser" 2015-01-12 10:15:13 -07:00
.gitmodules make .gnulib a submodule 2009-07-08 16:17:51 +02:00
.mailmap maint: update .mailmap 2014-12-21 00:21:34 +01:00
AUTHORS.in Update my email address in AUTHORS.in 2014-12-19 22:30:31 +01:00
autobuild.sh Disable libvirtd by default when building on Win32 2014-04-29 11:30:32 +01:00
autogen.sh maint: improve usage of autogen's --no-git 2015-02-06 11:35:29 -07:00
bootstrap maint: update to latest gnulib 2015-01-05 16:05:12 +00:00
bootstrap.conf Revert "bootstrap.conf: add check for flex" 2015-01-12 10:14:30 -07:00
cfg.mk Make tests independant of system page size 2015-02-02 20:27:43 +00:00
ChangeLog-old Fix typos in src/* 2014-04-21 16:49:08 -06:00
config-post.h build: fix build of virt-login-shell on systems with older gnutls 2013-10-22 09:41:50 -06:00
configure.ac Post-release version bump for new dev cycle 2015-03-02 07:38:43 +01:00
COPYING maint: follow recommended practice for using LGPL 2013-05-20 14:15:21 -06:00
COPYING.LESSER maint: follow recommended practice for using LGPL 2013-05-20 14:15:21 -06:00
HACKING docs: Fix missing curly braces 2014-12-10 11:21:31 +01:00
libvirt-lxc.pc.in Add pkg-config files for libvirt-qemu & libvirt-lxc 2014-06-23 16:17:27 +01:00
libvirt-qemu.pc.in Add pkg-config files for libvirt-qemu & libvirt-lxc 2014-06-23 16:17:27 +01:00
libvirt.pc.in Add pkg-config files for libvirt-qemu & libvirt-lxc 2014-06-23 16:17:27 +01:00
libvirt.spec.in Release of libvirt-1.2.13 2015-03-02 11:40:05 +08:00
Makefile.am examples: Introduce domtop 2014-07-18 16:39:54 +02:00
Makefile.nonreentrant maint: use LGPL correctly 2013-05-20 14:03:48 -06:00
mingw-libvirt.spec.in Move virConnect related APIs out of libvirt.h.in 2014-10-24 17:23:51 +01:00
README Correct typos in the documentation (Atsushi SAKAI) 2008-01-24 10:15:13 +00:00
README-hacking docs: update README-hacking 2014-05-06 16:20:24 -06:00
run.in Add PKG_CONFIG_PATH to run.in script. 2014-06-26 14:32:35 +01:00
TODO Update todo list file to point at bugzilla/website 2010-10-13 16:45:26 +01:00

         LibVirt : simple API for virtualization

  Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.

Daniel Veillard <veillard@redhat.com>