1. 04 1月, 2012 1 次提交
  2. 03 1月, 2012 1 次提交
    • E
      domiftune: clean up previous patches · 269ce467
      Eric Blake 提交于
      Most severe here is a latent (but currently untriggered) memory leak
      if any hypervisor ever adds a string interface property; the
      remainder are mainly cosmetic.
      
      * include/libvirt/libvirt.h.in (VIR_DOMAIN_BANDWIDTH_*): Move
      macros closer to interface that uses them, and document type.
      * src/libvirt.c (virDomainSetInterfaceParameters)
      (virDomainGetInterfaceParameters): Formatting tweaks.
      * daemon/remote.c (remoteDispatchDomainGetInterfaceParameters):
      Avoid memory leak.
      * src/libvirt_public.syms (LIBVIRT_0.9.9): Sort lines.
      * src/libvirt_private.syms (domain_conf.h): Likewise.
      * src/qemu/qemu_driver.c (qemuDomainSetInterfaceParameters): Fix
      comments, break long lines.
      269ce467
  3. 29 12月, 2011 1 次提交
  4. 21 12月, 2011 1 次提交
  5. 08 12月, 2011 1 次提交
  6. 30 11月, 2011 3 次提交
    • D
      Fix leak build config file path · 87e8ff1b
      Daniel P. Berrange 提交于
      * src/libvirt.c: Free user directory path
      87e8ff1b
    • L
      Add new API virDomain{Set, Get}BlockIoTune · 1f8a339d
      Lei Li 提交于
      This patch add new pulic API virDomainSetBlockIoTune and
      virDomainGetBlockIoTune.
      Signed-off-by: NLei Li <lilei@linux.vnet.ibm.com>
      Signed-off-by: NZhi Yong Wu <wuzhy@linux.vnet.ibm.com>
      Signed-off-by: NEric Blake <eblake@redhat.com>
      1f8a339d
    • E
      API: prevent query of --live and --config at once · 4199f3de
      Eric Blake 提交于
      Drivers were inconsistent when presented both --live and --config
      at once.  For example, within qemu, getting memory parameters
      favored live, getting blkio tuning favored config, and getting
      scheduler parameters errored out.  Also, some, but not all,
      attempts to mix flags on query were filtered at the virsh level.
      We shouldn't have to duplicate efforts in every client app, nor
      in every driver.  So, it is simpler to just enforce that the two
      flags cannot both be used at once on query operations, which has
      precedent in libvirt.c, and which matches the documentation of
      virDomainModificationImpact.
      
      * src/libvirt.c (virDomainGetMemoryParameters)
      (virDomainGetBlkioParameters)
      (virDomainGetSchedulerParametersFlags, virDomainGetVcpuPinInfo):
      Borrow sanity checking from virDomainGetVcpusFlags.
      4199f3de
  7. 29 11月, 2011 3 次提交
    • O
      block_resize: Define the new API · caef87d5
      Osier Yang 提交于
      The new API is named as "virDomainBlockResize", intending to add
      support for qemu monitor command "block_resize" (both HMP and QMP).
      
      Similar with APIs like "virDomainSetMemoryFlags", the units for
      argument "size" is kilobytes.
      caef87d5
    • S
      Implement the core API to suspend/resume the host · 4ddb37c3
      Srivatsa S. Bhat 提交于
      Add the core functions that implement the functionality of the API.
      Suspend is done by using an asynchronous mechanism so that we can return
      the status to the caller before the host gets suspended. This asynchronous
      operation is achieved by suspending the host in a separate thread of
      execution. However, returning the status to the caller is only best-effort,
      but not guaranteed.
      
      To resume the host, an RTC alarm is set up (based on how long we want to
      suspend) before suspending the host. When this alarm fires, the host
      gets woken up.
      
      Suspend-to-RAM operation on a host running Linux can take upto more than 20
      seconds, depending on the load of the system. (Freezing of tasks, an operation
      preceding any suspend operation, is given up after a 20 second timeout).
      And Suspend-to-Disk can take even more time, considering the time required
      for compaction, creating the memory image and writing it to disk etc.
      So, we do not allow the user to specify a suspend duration of less than 60
      seconds, to be on the safer side, since we don't want to prematurely declare
      failure when we only had to wait for some more time.
      4ddb37c3
    • S
      Add a public API to invoke suspend/resume on the host · 979676e3
      Srivatsa S. Bhat 提交于
      Implement the public definitions for the new API
      virNodeSuspendForDuration() which will be subsequently used to
      do a timed suspend on the host.
      979676e3
  8. 24 11月, 2011 2 次提交
    • J
      Introduce virConnectIsAlive API · afdf014f
      Jiri Denemark 提交于
      This API can be used to check if the socket associated with
      virConnectPtr is still open or it was closed (probably because keepalive
      protocol timed out). If there the connection is local (i.e., no socket
      is associated with the connection, it is trivially always alive.
      afdf014f
    • J
      Introduce virConnectSetKeepAlive · 8d6e3edd
      Jiri Denemark 提交于
      virConnectSetKeepAlive public API can be used by a client connecting to
      remote server to start using keepalive protocol. The API is handled
      directly by remote driver and not transmitted over the wire to the
      server.
      8d6e3edd
  9. 23 11月, 2011 3 次提交
    • E
      API: prefer 'disk' over 'block' or 'path' · 3ac26e26
      Eric Blake 提交于
      Given that we can now handle the target's disk shorthand, in addition
      to an absolute path to the file or block device used on the host,
      the term 'disk' fits a bit better as the parameter name than 'path'.
      
      * include/libvirt/libvirt.h.in: Update some parameter names.
      * src/libvirt.c (virDomainBlockStats, virDomainBlockStatsFlags)
      (virDomainBlockPeek, virDomainGetBlockInfo, virDomainBlockJobAbort)
      (virDomainGetBlockJobInfo, virDomainBlockJobSetSpeed)
      (virDomainBlockPull): Likewise.
      3ac26e26
    • E
      blockstats: support lookup by path in blockstats · c725e2dc
      Eric Blake 提交于
      Commit 89b6284f made it possible to pass either a source name or
      the target device to most API demanding a disk designation, but
      forgot to update the documentation.  It also failed to update
      virDomainBlockStats to take both forms. This patch fixes both the
      documentation and the remaining function.
      
      Xen continues to use just device shorthand (that is, I did not
      implement path lookup there, since xen does not track a domain_conf
      to quickly tie a path back to the device shorthand).
      
      * src/libvirt.c (virDomainBlockStats, virDomainBlockStatsFlags)
      (virDomainGetBlockInfo, virDomainBlockPeek)
      (virDomainBlockJobAbort, virDomainGetBlockJobInfo)
      (virDomainBlockJobSetSpeed, virDomainBlockPull): Document
      acceptable disk naming conventions.
      * src/qemu/qemu_driver.c (qemuDomainBlockStats)
      (qemuDomainBlockStatsFlags): Allow lookup by source name.
      * src/test/test_driver.c (testDomainBlockStats): Likewise.
      c725e2dc
    • E
      fix error message when using wrong URI alias · 5c5e07b8
      Eli Qiao 提交于
      Signed-off-by: NEli Qiao <taget@linux.vnet.ibm.com>
      
      When configuring a URI alias like this in 'libvirt.conf':
      
      uri_aliases = [
        "jj#j=qemu+ssh://root@127.0.0.1/system",
        "sleet=qemu+ssh://root@sleet.cloud.example.com/system",
      ]
      virsh -c jj#j
      
      It will show this error message:
      'no connection driver available for No connection for URI jj#j'
      Actually,we expect this message below:
      Malformed 'uri_aliases' config entry 'jj#j=qemu+ssh://root@127.0.0.1/system', aliases may only contain 'a-Z, 0-9, _, -'
      
      Give this patch to fix this error.
      5c5e07b8
  10. 12 11月, 2011 1 次提交
    • E
      API: add VIR_TYPED_PARAM_STRING · a218c81d
      Eric Blake 提交于
      This allows strings to be transported between client and server
      in the context of name-type-value virTypedParameter functions.
      For compatibility,
      
          o new clients will not send strings to old servers, based on
            a feature check
          o new servers will not send strings to old clients without the
            flag VIR_TYPED_PARAM_STRING_OKAY; this will be enforced at
            the RPC layer in the next patch, so that drivers need not
            worry about it in general.  The one exception is that
            virDomainGetSchedulerParameters lacks a flags argument, so
            it must not return a string; drivers that forward that
            function on to virDomainGetSchedulerParametersFlags will
            have to pay attention to the flag.
          o the flag VIR_TYPED_PARAM_STRING_OKAY is set automatically,
            based on a feature check (so far, no driver implements it),
            so clients do not have to worry about it
      
      Future patches can then enable the feature on a per-driver basis.
      
      This patch also ensures that drivers can blindly strdup() field
      names (previously, a malicious client could stuff 80 non-NUL bytes
      into field and cause a read overrun).
      
      * src/libvirt_internal.h (VIR_DRV_FEATURE_TYPED_PARAM_STRING): New
      driver feature.
      * src/libvirt.c (virTypedParameterValidateSet)
      (virTypedParameterSanitizeGet): New helper functions.
      (virDomainSetMemoryParameters, virDomainSetBlkioParameters)
      (virDomainSetSchedulerParameters)
      (virDomainSetSchedulerParametersFlags)
      (virDomainGetMemoryParameters, virDomainGetBlkioParameters)
      (virDomainGetSchedulerParameters)
      (virDomainGetSchedulerParametersFlags, virDomainBlockStatsFlags):
      Use them.
      * src/util/util.h (virTypedParameterArrayClear): New helper
      function.
      * src/util/util.c (virTypedParameterArrayClear): Implement it.
      * src/libvirt_private.syms (util.h): Export it.
      Based on an initial patch by Hu Tao, with feedback from
      Daniel P. Berrange.
      Signed-off-by: NEric Blake <eblake@redhat.com>
      a218c81d
  11. 02 11月, 2011 2 次提交
  12. 28 10月, 2011 1 次提交
    • D
      Introduce the virDomainOpenGraphics API · 9d96f1ce
      Daniel P. Berrange 提交于
      The virDomainOpenGraphics API allows a libvirt client to pass in
      a file descriptor for an open socket pair, and get it connected
      to the graphics display of the guest. This is limited to working
      with local libvirt hypervisors connected over a UNIX domain
      socket, since it will use UNIX FD passing
      
      * include/libvirt/libvirt.h.in: Define virDomainOpenGraphics
      * src/driver.h: Define driver for virDomainOpenGraphics
      * src/libvirt_public.syms, src/libvirt.c: Entry point for
        virDomainOpenGraphics
      * src/libvirt_internal.h: VIR_DRV_FEATURE_FD_PASSING
      9d96f1ce
  13. 25 10月, 2011 1 次提交
    • E
      waitpid: improve safety · 69d044c0
      Eric Blake 提交于
      Based on a report by Coverity.  waitpid() can leak resources if it
      fails with EINTR, so it should never be used without checking return
      status.  But we already have a helper function that does that, so
      use it in more places.
      
      * src/lxc/lxc_container.c (lxcContainerAvailable): Use safer
      virWaitPid.
      * daemon/libvirtd.c (daemonForkIntoBackground): Likewise.
      * tests/testutils.c (virtTestCaptureProgramOutput, virtTestMain):
      Likewise.
      * src/libvirt.c (virConnectAuthGainPolkit): Simplify with virCommand.
      69d044c0
  14. 19 10月, 2011 1 次提交
    • D
      Allow for URI aliases when connecting to libvirt · 777ffbd0
      Daniel P. Berrange 提交于
      This adds support for a libvirt client configuration file
      either /etc/libvirt/libvirt.conf for privileged clients,
      or $HOME/.libvirt/libvirt.conf for unprivileged clients.
      
      It allows one parameter
      
       uri_aliases = [
         "hail=qemu+ssh://root@hail.cloud.example.com/system",
         "sleet=qemu+ssh://root@sleet.cloud.example.com/system",
       ]
      
      Any call to virConnectOpen with a non-NULL URI will first
      attempt to match against the uri_aliases list. An application
      can disable this by using VIR_CONNECT_NO_ALIASES
      
      * docs/uri.html.in: Document URI aliases
      * include/libvirt/libvirt.h.in: Add VIR_CONNECT_NO_ALIASES
      * libvirt.spec.in, mingw32-libvirt.spec.in: Add /etc/libvirt/libvirt.conf
      * src/Makefile.am: Install default config file
      * src/libvirt.c: Add support for URI aliases
      * src/remote/remote_driver.c: Don't try to handle URIs
        with no scheme and which clearly are not paths
      * src/util/conf.c: Don't raise error on virConfFree(NULL)
      * src/xen/xen_driver.c: Don't raise error on URIs
        with no scheme
      777ffbd0
  15. 15 10月, 2011 1 次提交
  16. 13 10月, 2011 2 次提交
    • M
      virDomainCoreDump: Introduce VIR_DUMP_RESET flag · 4dadfe59
      Michal Privoznik 提交于
      This flag is intended to allow user to do so called system reset
      after dump, instead of sending ACPI reboot event.
      4dadfe59
    • E
      snapshot: add API for filtering by leaves · 8b6d1a20
      Eric Blake 提交于
      Counterpart to --roots.
      
      * include/libvirt/libvirt.h.in (VIR_DOMAIN_SNAPSHOT_LIST_LEAVES):
      New flag.
      * src/libvirt.c (virDomainSnapshotNum, virDomainSnapshotListNames)
      (virDomainSnapshotNumChildren)
      (virDomainSnapshotListChildrenNames): Document it.
      * tools/virsh.c (cmdSnapshotList): Expose it.
      * tools/virsh.pod (snapshot-list): Document --leaves.
      8b6d1a20
  17. 11 10月, 2011 1 次提交
    • E
      snapshot: new virDomainSnapshotListChildrenNames API · f2013c9d
      Eric Blake 提交于
      The previous API addition allowed traversal up the hierarchy;
      this one makes it easier to traverse down the hierarchy.
      
      In the python bindings, virDomainSnapshotNumChildren can be
      generated, but virDomainSnapshotListChildrenNames had to copy
      from the hand-written example of virDomainSnapshotListNames.
      
      * include/libvirt/libvirt.h.in (virDomainSnapshotNumChildren)
      (virDomainSnapshotListChildrenNames): New prototypes.
      (VIR_DOMAIN_SNAPSHOT_LIST_DESCENDANTS): New flag alias.
      * src/libvirt.c (virDomainSnapshotNumChildren)
      (virDomainSnapshotListChildrenNames): New functions.
      * src/libvirt_public.syms: Export them.
      * src/driver.h (virDrvDomainSnapshotNumChildren)
      (virDrvDomainSnapshotListChildrenNames): New callbacks.
      * python/generator.py (skip_impl, nameFixup): Update lists.
      * python/libvirt-override-api.xml: Likewise.
      * python/libvirt-override.c
      (libvirt_virDomainSnapshotListChildrenNames): New wrapper function.
      f2013c9d
  18. 06 10月, 2011 1 次提交
    • E
      snapshot: add REVERT_FORCE to API · 3c797404
      Eric Blake 提交于
      Although reverting to a snapshot is a form of data loss, this is
      normally expected.  However, there are two cases where additional
      surprises (failure to run the reverted state, or a break in
      connectivity to the domain) can come into play.  Requiring extra
      acknowledgment in these cases will make it less likely that
      someone can get into an unrecoverable state due to a default revert.
      
      Also create a new error code, so users can distinguish when forcing
      would make a difference, rather than having to blindly request force.
      
      * include/libvirt/libvirt.h.in (VIR_DOMAIN_SNAPSHOT_REVERT_FORCE):
      New flag.
      * src/libvirt.c (virDomainRevertToSnapshot): Document it.
      * include/libvirt/virterror.h (VIR_ERR_SNAPSHOT_REVERT_RISKY): New
      error value.
      * src/util/virterror.c (virErrorMsg): Implement it.
      * tools/virsh.c (cmdDomainSnapshotRevert): Add --force to virsh.
      * tools/virsh.pod (snapshot-revert): Document it.
      3c797404
  19. 29 9月, 2011 1 次提交
  20. 28 9月, 2011 1 次提交
    • E
      snapshot: new virDomainSnapshotGetParent API · a2f706de
      Eric Blake 提交于
      Although a client can already obtain a snapshot's parent by
      dumping and parsing the xml, then doing a snapshot lookup by
      name, it is more efficient to get the parent in one step, which
      in turn will make operations that must traverse a snapshot
      hierarchy easier to perform.
      
      * include/libvirt/libvirt.h.in (virDomainSnapshotGetParent):
      Declare.
      * src/libvirt.c (virDomainSnapshotGetParent): New function.
      * src/libvirt_public.syms: Export it.
      * src/driver.h (virDrvDomainSnapshotGetParent): New callback.
      a2f706de
  21. 21 9月, 2011 1 次提交
  22. 16 9月, 2011 2 次提交
  23. 08 9月, 2011 1 次提交
    • E
      snapshot: new APIs for inspecting snapshot object · 6c14439e
      Eric Blake 提交于
      These functions access internals of the opaque object, and do
      not need any rpc counterpart.  It could be argued that we should
      have provided these when snapshot objects were first introduced,
      since all the other vir*Ptr objects have at least a GetName accessor.
      
      * include/libvirt/libvirt.h.in (virDomainSnapshotGetName)
      (virDomainSnapshotGetDomain, virDomainSnapshotGetConnect): Declare.
      * src/libvirt.c (virDomainSnapshotGetName)
      (virDomainSnapshotGetDomain, virDomainSnapshotGetConnect): New
      functions.
      * src/libvirt_public.syms: Export them.
      6c14439e
  24. 06 9月, 2011 1 次提交
  25. 05 9月, 2011 3 次提交
    • E
      snapshot: add flag for requesting disk snapshot · e03a62b4
      Eric Blake 提交于
      Prior to this patch, <domainsnapshot>/<disks> was ignored.  This
      changes it to be an error unless an explicit disk snapshot is
      requested (a future patch may relax things if it turns out to
      be useful to have a <disks> specification alongside a system
      checkpoint).
      
      * include/libvirt/libvirt.h.in
      (VIR_DOMAIN_SNAPSHOT_CREATE_DISK_ONLY): New flag.
      * src/libvirt.c (virDomainSnapshotCreateXML): Document it.
      * src/esx/esx_driver.c (esxDomainSnapshotCreateXML): Disk
      snapshots not supported yet.
      * src/vbox/vbox_tmpl.c (vboxDomainSnapshotCreateXML): Likewise.
      * src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML): Likewise.
      e03a62b4
    • E
      snapshot: allow halting after snapshot · 6f66423e
      Eric Blake 提交于
      Since a snapshot is fully recoverable, it is useful to have a
      snapshot as a means of hibernating a guest, then reverting to
      the snapshot to wake the guest up.  This mode of usage is
      similar to 'virsh save/virsh restore', except that virsh
      save uses an external file while virsh snapshot keeps the
      vm state internal to a qcow2 file.  However, it only works on
      persistent domains.
      
      In the usage pattern of snapshot/revert for hibernating a guest,
      there is no need to keep the guest running between the two points
      in time, especially since that would generate runtime state that
      would just be discarded.  Add a flag to make it possible to
      stop the domain after the snapshot has completed.
      
      * include/libvirt/libvirt.h.in (VIR_DOMAIN_SNAPSHOT_CREATE_HALT):
      New flag.
      * src/libvirt.c (virDomainSnapshotCreateXML): Document it.
      * src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML)
      (qemuDomainSnapshotCreateActive): Implement it.
      6f66423e
    • E
      snapshot: introduce new deletion flag · 3d77d0a6
      Eric Blake 提交于
      Reverting to a state prior to an external snapshot risks
      corrupting any other branches in the snapshot hierarchy that
      were using the snapshot as a read-only backing file.  So
      disk snapshot code will default to preventing reverting to
      a snapshot that has any children, meaning that deleting just
      the children of a snapshot becomes a useful operation in
      preparing that snapshot for being a future reversion target.
      The code for the new flag is simple - it's one less deletion,
      plus a tweak to keep the current snapshot correct.
      
      * include/libvirt/libvirt.h.in
      (VIR_DOMAIN_SNAPSHOT_DELETE_CHILDREN_ONLY): New flag.
      * src/libvirt.c (virDomainSnapshotDelete): Document it, and
      enforce mutual exclusion.
      * src/qemu/qemu_driver.c (qemuDomainSnapshotDelete): Implement
      it.
      3d77d0a6
  26. 03 9月, 2011 3 次提交
    • E
      snapshot: allow full domain xml in snapshot · f609cb85
      Eric Blake 提交于
      Just like VM saved state images (virsh save), snapshots MUST
      track the inactive domain xml to detect any ABI incompatibilities.
      
      The indentation is not perfect, but functionality comes before form.
      
      Later patches will actually supply a full domain; for now, this
      wires up the storage to support one, but doesn't ever generate one
      in dumpxml output.
      
      Happily, libvirt.c was already rejecting use of VIR_DOMAIN_XML_SECURE
      from read-only connections, even though before this patch, there was
      no information to be secured by the use of that flag.
      
      And while we're at it, mark the libvirt snapshot metadata files
      as internal-use only.
      
      * src/libvirt.c (virDomainSnapshotGetXMLDesc): Document flag.
      * src/conf/domain_conf.h (_virDomainSnapshotDef): Add member.
      (virDomainSnapshotDefParseString, virDomainSnapshotDefFormat):
      Update signature.
      * src/conf/domain_conf.c (virDomainSnapshotDefFree): Clean up.
      (virDomainSnapshotDefParseString): Optionally parse domain.
      (virDomainSnapshotDefFormat): Output full domain.
      * src/esx/esx_driver.c (esxDomainSnapshotCreateXML)
      (esxDomainSnapshotGetXMLDesc): Update callers.
      * src/vbox/vbox_tmpl.c (vboxDomainSnapshotCreateXML)
      (vboxDomainSnapshotGetXMLDesc): Likewise.
      * src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML)
      (qemuDomainSnapshotLoad, qemuDomainSnapshotGetXMLDesc)
      (qemuDomainSnapshotWriteMetadata): Likewise.
      * docs/formatsnapshot.html.in: Rework doc example.
      Based on a patch by Philipp Hahn.
      f609cb85
    • E
      snapshot: prevent stranding snapshot data on domain destruction · 282fe1f0
      Eric Blake 提交于
      Just as leaving managed save metadata behind can cause problems
      when creating a new domain that happens to collide with the name
      of the just-deleted domain, the same is true of leaving any
      snapshot metadata behind.  For safety sake, extend the semantic
      change of commit b26a9fa9 to also cover snapshot metadata as a
      reason to reject undefining an inactive domain.  A future patch
      will make sure that shutdown of a transient domain automatically
      deletes snapshot metadata (whether by destroy, shutdown, or
      guest-initiated action).  Management apps of transient domains
      should take care to capture xml of snapshots, if it is necessary
      to recreate the snapshot metadata on a later transient domain
      with the same name and uuid.
      
      This also documents a new flag that hypervisors can choose to
      support as a shortcut for taking care of the metadata as part of
      the undefine process; however, nontrivial driver support for these
      flags will be deferred to future patches.
      
      Note that ESX and VBox can never be transient; therefore, they
      do not have to worry about automatic cleanup after shutdown
      (the persistent domain still remains); likewise they never
      store snapshot metadata, so the undefine flag is trivial.
      The nontrivial work remaining is thus in the qemu driver.
      
      * include/libvirt/libvirt.h.in
      (VIR_DOMAIN_UNDEFINE_SNAPSHOTS_METADATA): New flag.
      * src/libvirt.c (virDomainUndefine, virDomainUndefineFlags):
      Document new limitations and flag.
      * src/esx/esx_driver.c (esxDomainUndefineFlags): Trivial
      implementation.
      * src/vbox/vbox_tmpl.c (vboxDomainUndefineFlags): Likewise.
      * src/qemu/qemu_driver.c (qemuDomainUndefineFlags): Enforce
      the limitations.
      282fe1f0
    • E
      snapshot: allow recreation of metadata · af65695a
      Eric Blake 提交于
      The first two flags are essential for being able to replicate
      snapshot hierarchies across multiple hosts, which will come in
      handy for supervised migrations.  It also allows a management app
      to take a snapshot of a transient domain, save the metadata, stop
      the domain, recreate a new transient domain by the same name,
      redefine the snapshot, then revert to it.
      
      This is not quite as convenient as leaving the metadata behind
      after a domain is no longer around, but doing that has a few
      problems: 1. the libvirt API can only delete snapshot metadata
      if there is a valid domain handle to use to get to that snapshot
      object - if stale data is left behind without a domain, there is
      no way to request that the data be cleaned up. 2. creating a new
      domain with the same name but different uuid than the older
      domain where a snapshot existed cannot use the older snapshot
      data; this risks confusing libvirt, and forbidding the stale
      data is similar to the recent patch to forbid stale managed save.
      
      The first two flags might be useful on hypervisors with no metadata,
      but only for modifying the notion of the current snapshot;
      however, I don't know how to do that for ESX or VBox.
      
      The third flag is a convenience option, to combine a creation with
      a delete metadata into one step.  It is trivial for hypervisors
      with no metadata.
      
      The qemu changes will be involved enough to warrant a separate patch.
      
      * include/libvirt/libvirt.h.in
      (VIR_DOMAIN_SNAPSHOT_CREATE_REDEFINE)
      (VIR_DOMAIN_SNAPSHOT_CREATE_CURRENT)
      (VIR_DOMAIN_SNAPSHOT_CREATE_NO_METADATA): New flags.
      * src/libvirt.c (virDomainSnapshotCreateXML): Document them, and
      enforce mutual exclusion.
      * src/esx/esx_driver.c (esxDomainSnapshotCreateXML): Trivial
      implementation.
      * src/vbox/vbox_tmpl.c (vboxDomainSnapshotCreateXML): Likewise.
      * docs/formatsnapshot.html.in: Document re-creation.
      af65695a