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Martin Kletzander 540c339a25 qemu: completely rework reference counting
There is one problem that causes various errors in the daemon.  When
domain is waiting for a job, it is unlocked while waiting on the
condition.  However, if that domain is for example transient and being
removed in another API (e.g. cancelling incoming migration), it get's
unref'd.  If the first call, that was waiting, fails to get the job, it
unref's the domain object, and because it was the last reference, it
causes clearing of the whole domain object.  However, when finishing the
call, the domain must be unlocked, but there is no way for the API to
know whether it was cleaned or not (unless there is some ugly temporary
variable, but let's scratch that).

The root cause is that our APIs don't ref the objects they are using and
all use the implicit reference that the object has when it is in the
domain list.  That reference can be removed when the API is waiting for
a job.  And because each domain doesn't do its ref'ing, it results in
the ugly checking of the return value of virObjectUnref() that we have
everywhere.

This patch changes qemuDomObjFromDomain() to ref the domain (using
virDomainObjListFindByUUIDRef()) and adds qemuDomObjEndAPI() which
should be the only function in which the return value of
virObjectUnref() is checked.  This makes all reference counting
deterministic and makes the code a bit clearer.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
2014-12-21 10:48:56 +01:00
.gnulib@3914f31535 maint: update to latest gnulib 2014-12-08 16:48:11 -07:00
build-aux bracket-spacing: Add syntax-check for unnecessary curly brackets 2014-11-14 17:13:36 +01:00
daemon virconf: Introduce VIR_CONF_ULONG 2014-12-15 10:34:18 +01:00
docs storage: unify permission formatting 2014-12-16 15:47:56 +01:00
examples examples: Add support for the guest agent lifecycle event 2014-11-24 15:47:01 +01:00
gnulib maint: update to latest gnulib 2014-01-01 06:02:47 -07:00
include Fix typo s/interpetation/interpretation/ 2014-12-20 22:29:11 +01:00
m4 avoid using deprecated udev logging functions 2014-12-15 18:08:45 +00:00
po Release of libvirt-1.2.11 2014-12-13 10:43:56 +08:00
src qemu: completely rework reference counting 2014-12-21 10:48:56 +01:00
tests qemu: Create memory-backend-{ram,file} iff needed 2014-12-19 07:44:44 +01:00
tools getstats: add new flag for block backing chain 2014-12-17 01:41:38 -07:00
.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 gitignore: use wildcard for configure's temporary files 2014-11-06 16:56:21 +01:00
.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
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
ChangeLog-old Fix typos in src/* 2014-04-21 16:49:08 -06:00
HACKING docs: Fix missing curly braces 2014-12-10 11:21:31 +01:00
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
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
TODO Update todo list file to point at bugzilla/website 2010-10-13 16:45:26 +01:00
autobuild.sh Disable libvirtd by default when building on Win32 2014-04-29 11:30:32 +01:00
autogen.sh maint: detect VPATH builds when checking for gnulib update 2014-06-04 16:06:55 -06:00
bootstrap maint: update to latest gnulib 2014-12-08 16:48:11 -07:00
bootstrap.conf build: Move check for XML::XPath into bootstrap 2014-12-09 08:23:21 +01:00
cfg.mk Replace virDomainSnapshotFree with virObjectUnref 2014-12-02 11:03:41 -05:00
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 2014-12-13 10:01:31 +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 spec: Fix syntax 2014-12-16 09:21:40 +01:00
mingw-libvirt.spec.in Move virConnect related APIs out of libvirt.h.in 2014-10-24 17:23:51 +01:00
run.in Add PKG_CONFIG_PATH to run.in script. 2014-06-26 14:32:35 +01:00

README

         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>