Adam Litke 9c7c4a4fc5 Allow non-file disk backingStores
I am trying to use a qcow image with libvirt where the backing 'file' is a
qemu-nbd server.  Unfortunately virDomainDiskDefForeachPath() assumes that
backingStore is always a real file so something like 'nbd:0:3333' is rejected
because a file with that name cannot be accessed.  Note that I am not worried
about directly using nbd images.  That would require a new disk type with XML
markup, etc.  I only want it to be permitted as a backingStore

The following patch implements danpb's suggestion:
> I think I'm inclined to push the logic for skipping NBD one stage higher.
> I'd rather expect virStorageFileGetMetadata() to return all backing
> stores, even if not files. The virDomainDiskDefForeachPath() method
> should definitely ignore non-file backing stores though.
>
> So what I'm thinking is to extend the virStorageFileMetadata struct and
> just add a 'bool isFile' field to it. Default this field to true, unless
> you see the prefix of nbd: in which case set it to false. The
> virDomainDiskDefForeachPath() method can then skip over any backing
> store with isFile == false

Signed-off-by: Adam Litke <agl@us.ibm.com>
Cc: Daniel P. Berrange <berrange@redhat.com>
2010-11-09 16:40:27 -07:00
..
2010-11-09 16:40:27 -07:00
2010-11-09 16:40:27 -07:00
2010-10-12 09:42:18 -06:00
2010-06-21 10:11:34 +02:00
2010-04-05 10:24:34 -04:00
2010-10-19 10:00:47 -06:00
2010-05-25 10:48:10 -04:00
2010-02-18 15:13:48 +01:00
2010-10-19 10:00:17 -06:00
2010-07-23 17:30:14 -04:00

       libvirt library code README
       ===========================

The directory provides the bulk of the libvirt codebase. Everything
except for the libvirtd daemon and client tools. The build uses a
large number of libtool convenience libraries - one for each child
directory, and then links them together for the final libvirt.so,
although some bits get linked directly to libvirtd daemon instead.

The files directly in this directory are supporting the public API
entry points & data structures.

There are two core shared modules to be aware of:

 * util/  - a collection of shared APIs that can be used by any
            code. This directory is always in the include path
            for all things built

 * conf/  - APIs for parsing / manipulating all the official XML
            files used by the public API. This directory is only
            in the include path for driver implementation modules


Then there are the hypervisor implementations:

 * esx/          - VMware ESX and GSX support using vSphere API over SOAP
 * lxc/          - Linux Native Containers
 * opennebula/   - Open Nebula using XMLRPC
 * openvz/       - OpenVZ containers using cli tools
 * phyp/         - IBM Power Hypervisor using CLI tools over SSH
 * qemu/         - QEMU / KVM using qemu CLI/monitor
 * remote/       - Generic libvirt native RPC client
 * test/         - A "mock" driver for testing
 * uml/          - User Mode Linux
 * vbox/         - Virtual Box using native API
 * xen/          - Xen using hypercalls, XenD SEXPR & XenStore


Finally some secondary drivers that are shared for several HVs.
Currently these are used by LXC, OpenVZ, QEMU, UML and Xen drivers.
The ESX, OpenNebula, Power Hypervisor, Remote, Test & VirtualBox
drivers all implement the secondary drivers directly

 * interface/    - Host network interface management
 * network/      - Virtual NAT networking
 * node_device/  - Host device enumeration
 * secret/       - Secret management
 * security/     - Mandatory access control drivers
 * storage/      - Storage management drivers


Since both the hypervisor and secondary drivers can be built as
dlopen()able modules, it is *FORBIDDEN* to have build dependencies
between these directories. Drivers are only allowed to depend on
the public API, and the internal APIs in the util/ and conf/
directories