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Eric Blake
2e13b9ab3c
Right now, starting from just a virDomainSnapshotPtr, and wanting to know if it is the current snapshot for its respective domain, you have to use virDomainSnapshotGetDomain(), then virDomainSnapshotCurrent(), then compare the two names returned by virDomainSnapshotGetName(). It is a bit easier if we can directly query this information from the snapshot itself. Right now, it is possible to filter a snapshot listing based on whether snapshots have metadata that would prevent domain deletion, but the only way to learn if an individual snapshot has metadata is to see if that snapshot appears in the list returned by a listing. Additionally, I hope to expand the qemu driver in a future patch to use qemu-img to reconstruct snapshot XML corresponding to internal qcow2 snapshot names not otherwise tracked by libvirt (in part, so that libvirt can guarantee that new snapshots are not created with a name that would silently corrupt the existing portion of the qcow2 file); if I ever get that in, then it would no longer be an all-or-none decision on whether snapshots have metadata, and becomes all the more important to be able to directly determine that information from a particular snapshot. Other query functions (such as virDomainIsActive) do not have a flags argument, but since virDomainHasCurrentSnapshot takes a flags argument, I figured it was safer to provide a flags argument here as well. * include/libvirt/libvirt.h.in (virDomainSnapshotIsCurrent) (virDomainSnapshotHasMetadata): New declarations. * src/libvirt.c (virDomainSnapshotIsCurrent) (virDomainSnapshotHasMetadata): New functions. * src/libvirt_public.syms (LIBVIRT_0.9.13): Export them. * src/driver.h (virDrvDomainSnapshotIsCurrent) (virDrvDomainSnapshotHasMetadata): New driver callbacks.
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
* vmx/ - VMware VMX config handling (used by esx/ and vmware/)
Then there are the hypervisor implementations:
* esx/ - VMware ESX and GSX support using vSphere API over SOAP
* hyperv/ - Microsoft Hyper-V support using WinRM
* lxc/ - Linux Native Containers
* 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
* vmware/ - VMware Workstation and Player using the vmrun tool
* xen/ - Xen using hypercalls, XenD SEXPR & XenStore
* xenapi/ - Xen using libxenserver
Finally some secondary drivers that are shared for several HVs.
Currently these are used by LXC, OpenVZ, QEMU, UML and Xen drivers.
The ESX, Hyper-V, Power Hypervisor, Remote, Test & VirtualBox drivers all
implement the secondary drivers directly
* cpu/ - CPU feature management
* interface/ - Host network interface management
* network/ - Virtual NAT networking
* nwfilter/ - Network traffic filtering rules
* 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