Michal Privoznik 13284a6b83 storage_driver: Protect pool def during startup and build
In near future the storage pool object lock will be released
during startPool and buildPool callback (in some backends). But
this means that another thread may acquire the pool object lock
and change its definition rendering the former thread access not
only stale definition but also access freed memory
(virStoragePoolObjAssignDef() will free old def when setting a
new one).

One way out of this would be to have the pool appear as active
because our code deals with obj->def and obj->newdef just fine.
But we can't declare a pool as active if it's not started or
still building up. Therefore, have a boolean flag that is very
similar and forces virStoragePoolObjAssignDef() to store new
definition in obj->newdef even for an inactive pool. In turn, we
have to move the definition to correct place when unsetting the
flag. But that's as easy as calling
virStoragePoolUpdateInactive().

Technically speaking, change made to
storageDriverAutostartCallback() is not needed because until
storage driver is initialized no storage API can run therefore
there can't be anyone wanting to change the pool's definition.
But I'm doing the change there for consistency anyways.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-08-23 09:32:26 +02:00
..
2019-08-22 16:46:44 +02:00
2019-08-09 14:06:31 +01:00
2019-08-09 14:06:31 +01:00
2019-06-19 17:12:33 +02:00
2019-07-09 10:27:20 +02:00
2019-08-07 14:26:12 +01:00

       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

 * vmx/   - VMware VMX config handling (used by esx/ and vmware/)


Then there are the hypervisor implementations:

 * bhyve         - bhyve - The BSD Hypervisor
 * 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
 * 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 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