[libvirt] [PATCH 0/9] qemu: Add quorum support to libvirt
mprivozn at redhat.com
Tue Jan 13 14:45:59 UTC 2015
On 08.12.2014 19:31, Matthias Gatto wrote:
> The purpose of these patches is to introduce quorum for libvirt
> I've try to follow this proposal:
> This feature ask for 6 task:
> 1) Allow a _virStorageSource
> to contain more than one backing store.
> Therefore we have to treat the field virStorageSourcePtr backingStores
> as an array instead of a pointer.
> But doing that, most of the backingStore field would be an array contening
> only one element.
> So I've decide to allocate the array only if there is more than 1
> backing store in a _virStorageSource.
> Because all the actual libvirt code use the backingStore field
> as a pointer and we needs want to change that, I've decide to encapsulate
> the backingStore field to simplifie the array manipulation.
> 2) Add the missing field a quorum need in _virStorageSource and
> the VIR_STORAGE_TYPE_QUORUM and VIR_STORAGE_FILE_QUORUM in
> their respectives enums.
> 3) Parse and format the xml
> Because a quorum allows to have more than one backing store at the same level
> we need to change virDomainDiskDefFormat and virDomainDiskDefParseXML
> to call virDomainDiskBackingStoreFormat and virDomainDiskBackingStoreParse
> in a loop.
> virDomainDiskBackingStoreFormat and virDomainDiskBackingStoreParse can
> call themself recursively in a loop because a quorum can contain another
> 4) Add nodename
> We need to add nodename support in _virStorageSource because qemu
> use them for their child.
> 5) Build qemu string
> As for the xml, we have to call the function which create quorum recursively.
> But this task have the problem explained here:
> The _virStorageSource missing some informations that can be passed to
> a child, and therefore this version of quorum is incomplet.
> 6) Allow to hotplug/change a disk in a quorum
> This part is not present in these patches because for this task
> we have to use blockdev-add, and currently libvirt use
> device_add for hotpluging that doesn't allow to hotplug quorum childs.
> There is 3 way to handle this problem:
> 1) create a virDomainBlockDevAdd function in libvirt witch call
> 2) use blockdev-add instead of device_add in qemuMonitorJSONAddDevice
> 3) write a hack which uses blockdev-add when only attaching quorum
> (but i'm pretty sure this solution is not the good one)
> Matthias Gatto (9):
> virstoragefile: Add virStorageSourceGetBackingStore
> virstoragefile: Always use virStorageSourceGetBackingStore to get
> backing store
> virstoragefile: Add virStorageSourceSetBackingStore
> virstoragefile: Always use virStorageSourceSetBackingStore to set
> backing store
> virstoragefile: Treat backingStore as a pointer or an array
> virstoragefile: Add quorum in virstoragefile
> domain_conf: Read and Write quorum config
> qemu: Add quorum support in qemuBuildDriveDevStr
> virstoragefile: Add node-name
> src/conf/domain_conf.c | 193 ++++++++++++++++++++++++++--------
> src/conf/storage_conf.c | 7 +-
> src/libvirt_private.syms | 3 +
> src/qemu/qemu_cgroup.c | 4 +-
> src/qemu/qemu_command.c | 114 ++++++++++++++++++++
> src/qemu/qemu_domain.c | 3 +-
> src/qemu/qemu_driver.c | 20 ++--
> src/security/security_dac.c | 2 +-
> src/security/security_selinux.c | 4 +-
> src/security/virt-aa-helper.c | 2 +-
> src/storage/storage_backend.c | 12 +--
> src/storage/storage_backend_fs.c | 12 +--
> src/storage/storage_backend_logical.c | 4 +-
> src/storage/storage_driver.c | 2 +-
> src/util/virstoragefile.c | 136 +++++++++++++++++++++---
> src/util/virstoragefile.h | 12 +++
> tests/virstoragetest.c | 18 ++--
> 17 files changed, 445 insertions(+), 103 deletions(-)
In general, looks good to me. However, I can't ACK it due to missing
documentation. Moreover, you may want to rebase and resend - the code
has changed and there are new places where access backingStore directly.
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