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Michal Privoznik
0377177c78
When reconnecting to a running QEMU process, we construct the per-domain path in all hugetlbfs mounts. This is a relict from the past (v3.4.0-100-g5b24d25062) where we switched to a per-domain path and we want to create those paths when libvirtd restarts on upgrade. And with namespaces enabled there is one corner case where the path is not created. In fact an error is reported and the reconnect fails. Ideally, all mount events are propagated into the QEMU's namespace. And they probably are, except when the target path does not exist inside the namespace. Now, it's pretty common for users to mount hugetlbfs under /dev (e.g. /dev/hugepages), but if domain is started without hugepages (or more specifically - private hugetlbfs path wasn't created on domain startup), then the reconnect code tries to create it. But it fails to do so, well, it fails to set seclabels on the path because, because the path does not exist in the private namespace. And it doesn't exist because we specifically create only a subset of all possible /dev nodes. Therefore, the mount event, whilst propagated, is not successful and hence the filesystem is not mounted. We have to do it ourselves. If hugetlbfs is mount anywhere else there's no problem and this is effectively a dead code. Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2123196 Signed-off-by: Michal Privoznik <mprivozn@redhat.com> Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
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
* 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
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, 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