These are no longer called from qemu_driver.c, since the function that
called them (qemuDomainDetachDeviceLive()) has been moved to
qemu_hotplug.c, and they are no longer called from testqemuhotplug.c
because it now just called qemuDomainDetachDeviceLive() instead of all
the subordinate functions.
Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
qemuDomainDetachDeviceLive() is called from two places in
qemu_driver.c, and qemuDomainUpdateDeviceList() is called from the
end of qemuDomainDetachDeviceLive(), which is now in qemu_hotplug.c
This patch replaces the single call to qemuDomainUpdateDeviceList()
with two calls to it immediately after return from
qemuDomainDetachDeviceLive(). This is only done if the return from
that function is exactly 0, in order to exactly preserve previous
behavior.
Removing that one call from qemuDomainDetachDeviceList() will permit
us to call it from the test driver hotplug test, replacing the
separate calls to qemuDomainDetachDeviceDiskLive(),
qemuDomainDetachChrDevice(), qemuDomainDetachShmemDevice() and
qemuDomainDetachWatchdog(). We want to do this so that part of the
common functionality of those three functions (and the rest of the
device-specific Detach functions) can be pulled up into
qemuDomainDetachDeviceLive() without breaking the test. (This is done
in the next patch).
NB: Almost certainly this is "not the best place" to call
qemuDomainUpdateDeviceList() (actually, it is provably the *wrong*
place), since it's purpose is to retrieve an "up to date" list of
aliases for all devices from qemu, and if the guest OS hasn't yet
processed the detach request, the now-being-removed device may still
be on that list. It would arguably be better to instead call
qemuDomainUpdateDevicesList() later during the response to the
DEVICE_DELETED event for the device. But removing the call from the
current point in the detach could have some unforeseen ill effect due
to changed timing, so the change to move it into
qemuDomainRemove*Device() will be done in a separate patch (in order
to make it easily revertible in case it causes a regression).
Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
qemuDomainDetachDeviceControllerLive() just checks if the controller
type is SCSI, and then either returns failure, or calls
qemuDomainDetachControllerDevice().
Instead, lets just check for type != SCSI at the top of the latter
function, and call it directly.
Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
This function is going to take on some of the functionality of its
subordinate functions, which all live in qemu_hotplug.c.
qemuDomainDetachDeviceControllerLive() is only called from
qemuDomainDetachDeviceLive() (and will soon be merged into
qemuDomainDetachControllerDevice(), which is in qemu_hotplug.c), so
it is also moved.
Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
They were added in qemu commit 7572150c189c6553c2448334116ab717680de66d
released in v0.14.0.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Rather than hard-coding the snapshot filter bit values into the
generic code, add another layer of indirection: callers must map which
of their public filter bits correspond to supported moment bits, then
pass two separate flags (the ones translated for moment code to
operate on, and the remaining ones for the filter callback to operate
on).
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
The Attach and Detach Lease functions were together in the middle of
the Detach functions. Put them at the end of their respective
sections, since they behave differently from the other attach/detach
functions (DetachLease doesn't use qemuDomainDeleteDevice(), and is
always synchronous).
Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
There were two outliers at the end of the file beyond the Vcpu
functions.
Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
It was sitting down in the middle of all the qemuDomainDetach*()
functions. Move it up with the rest of the qemuDomain*Graphics*()
functions.
Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
It's now only called from one place, and combining the two functions
highlights the similarity with Detach functions for other device
types.
Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
Back in the bad old days different device types required a different
qemu monitor call to detach them, and so an <interface type='hostdev'>
needed to call the function for detaching hostdevs, while other
<interface> types could be deleted as netdevs.
Times have changed, and *all* device types are detached by calling the
common function qemuDomainDeleteDevice(vm, alias), so we don't need to
differentiate between hostdev interfaces and the others for that
reason.
There are a few other netdev-specific functions called during
qemuDomainDetachNetDevice() (clearing bandwidth limits, stopping the
interface), but those turn into NOPs when type=hostdev, so they're
safe to call for type=hostdev.
The only thing that is different + not a NOP is the call to
virDomainAudit*() when qemuDomainDeleteDevice() fails, so if we add a
conditional for that small bit of code, we can eliminate the callout
from qemuDomainDetachNetDevice() to qemuDomainDetachThisDevice(),
which makes this function fit the desired pattern for merging with the
other detach functions, and paves the way to simplifying
qemuDomainDetachHostDevice() too.
Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
qemuDomainDetachDiskDevice() is only called from one place. Moving the
contents of the function to that place makes
qemuDomainDetachDiskLive() more similar to the other Detach functions
called by the toplevel qemuDomainDetachDevice().
The goal is to make each of the device-type-specific functions do this:
1) find the exact device
2) do any device-specific validation
3) do general validation
4) do device-specific shutdown (only needed for net devices)
5) do the common block of code to send device_del to qemu, then
optionally wait for a corresponding DEVICE_DELETED event from
qemu.
with the final aim being that only items 1 & 2 will remain in each
device-type-specific function, while 3 & 5 (which are the same for
almost every type) will be de-duplicated and moved to the toplevel
function that calls all of these (qemuDomainDetachDeviceLive(), which
will also contain a callout to the one instance of (4) (netdev).
Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
qemuDomainDetachHostDevice() has a check at the end that calls
qemuDomainDetachNetDevice() in the case that the hostdev is actually a
Net device of type='hostdev'. A long time ago when device removal was
(supposedly but not actually) synchronous, this would cause some extra
code to be run prior to removing the device (e.g. restoring the original MAC
address of the device, undoing some sort of virtual port profile, etc).
For quite awhile now the device removal has been asynchronous, so that
"extra teardown" isn't handled by the detach function, but instead is
handled by the Remove function called at a later time. The result is
that when we call qemuDomainDetachNetDevice() from
qemuDomainDetachHostDevice(), it ends up just calling
qemuDomainDetachThisHostDevice() and returning, which is exactly what
we do for all other hostdevs anyway.
Based on that, remove the behavioral difference when parent.type ==
VIR_DOMAIN_DEVICE_NET, and just call qemuDomainDetachThisHostDevice()
for all hostdevs.
Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
There are separate Detach functions for PCI, USB, SCSI, Vhost, and
Mediated hostdevs, but the functions are all 100% the same code,
except that the PCI function checks for the guest side of the device
being a PCI Multifunction device, while the other 4 check that the
device's alias != NULL.
The check for multifunction PCI devices should be done for *all*
devices that are connected to the PCI bus in the guest, not just PCI
hostdevs, and qemuIsMultiFunctionDevice() conveniently returns false
if the queried device doesn't connect with PCI, so it is safe to make
this check for all hostdev devices. (It also needs to be done for many
other device types, but that will be addressed in a future patch).
Likewise, since all hostdevs are detached by calling
qemuDomainDeleteDevice(), which requires the device's alias, checking
for a valid alias is a reasonable thing for PCI hostdevs too.
Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Having an InfoPtr named "dev" made my brain hurt. Renaming it to
"info" gives one less thing to confuse when looking at the code.
Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
When support for hotplug/unplug of SCSI controllers was added way back
in December 2009 (commit da9d937b), unplug was handled by calling the
now-extinct function qemuMonitorRemovePCIDevice(), which required a
PCI address as an argument. At the same time, the idea of every device
in the config having a PCI address apparently was not yet fully
implemented, because the author of the patch including a check for a
valid PCI address in the device object.
These days, all PCI devices are guaranteed to have a valid PCI
address. But more important than that, we no longer detach devices by
PCI address, but instead use qemuDomainDeleteDevice(), which
identifies the device by its alias. So checking for a valid PCI
address is just pointless extra code that obscures the high level of
similarity between all the individual qemuDomainDetach*Device()
functions.
Signed-off-by: Laine Stump <laine@laine.org>
ACKed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
qemuDomainRemoveRNGDevice() calls qemuDomainDetachExtensionDevice().
According to commit 1d1e264f1 that added this code, it should not be
necessary to explicitly remove the zPCI extension device for a PCI
device during unplug, because "QEMU implements an unplug callback
which will unplug both PCI and zPCI device in a cascaded way". In
fact, no other devices call qemuDomainDetachExtensionDevice() during
their qemuDomainRemove*Device() function, so it should be removed from
qemuDomainRemoveRNGDevice as well.
Signed-off-by: Laine Stump <laine@laine.org>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
qemuDomainDetachControllerDevice() calls
qemuDomainDetachExtensionDevice() when the controller type is
PCI. This is incorrect in multiple ways:
* Any code that tears down a device should be in the
qemuDomainRemove*Device() function (which is called after libvirt
gets a DEVICE_DELETED event from qemu indicating that the guest is
finished with the device on its end. The qemuDomainDetach*Device()
functions should only contain code that ensures the requested
operation is valid, and sends the command to qemu to initiate the
unplug.
* qemuDomainDetachExtensionDevice() is a function that applies to
devices that plug into a PCI slot, *not* necessarily PCI controllers
(which is what's being checked in the offending code). The proper
way to check for this would be to see if the DeviceInfo for the
controller device had a PCI address, not to check if the controller
is a PCI controller (the code being removed was doing the latter).
* According to commit 1d1e264f1 that added this code (and other
support for hotplugging zPCI devices on s390), it's not necessary to
explicitly detach the zPCI device when unplugging a PCI device. To
quote:
There's no need to implement hot unplug for zPCI as QEMU
implements an unplug callback which will unplug both PCI and
zPCI device in a cascaded way.
and the evidence bears this out - all the other uses of
qemuDomainDetachExtensionDevice() (except one, which I believe is
also in error, and is being removed in a separate patch) are only to
remove the zPCI extension device in cases where it was successfully
added, but there was some other failure later in the hotplug process
(so there was no regular PCI device to remove and trigger removal of
the zPCI extension device).
* PCI controllers are not hot pluggable, so this is dead code
anyway. (The only controllers that can currently be
hotplugged/unplugged are SCSI controllers).
Signed-off-by: Laine Stump <laine@laine.org>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Commit 55c2ab3e accidentally introduced an infinite loop while
checking whether a redefined snapshot would cause an infinite loop in
chasing its parents back to a root. Alas, 'make check' did not catch
it, so my next patch will be a testsuite improvement that would have
hung and prevented the bug from being checked in to begin with.
Signed-off-by: Eric Blake <eblake@redhat.com>
Acked-by: Michal Privoznik <mprivozn@redhat.com>
In a case where we want to hotplug the following disk:
<disk type='file' device='disk'>
(...)
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
</disk>
In a QEMU guest that has a single OS disk, as follows:
<disk type='file' device='disk'>
(...)
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
</disk>
What happens is that the existing guest disk will receive the ID
'scsi0-0-0-0' due to how Libvirt calculate the alias based on
the address in qemu_alias.c, qemuAssignDeviceDiskAlias. When hotplugging
a disk that happens to have the same address, Libvirt will calculate
the same ID to it and attempt to device_add. QEMU will refuse it:
$ virsh attach-device ub1810 hp-disk-dup.xml
error: Failed to attach device from hp-disk-dup.xml
error: internal error: unable to execute QEMU command 'device_add': Duplicate ID 'scsi0-0-0-0' for device
And Libvirt follows it up with a cleanup code in qemuDomainAttachDiskGeneric
that ends up removing what supposedly is a faulty hotplugged disk but, in
this case, ends up being the original guest disk.
This patch adds an address verification for all attached devices, avoid
calling the driver attach() function using a device with duplicated address.
The change is done in virDomainDefCompatibleDevice when @action is equal
to VIR_DOMAIN_DEVICE_ACTION_ATTACH. The affected callers are:
- qemuDomainAttachDeviceLiveAndConfig, both LIVE and CONFIG cases;
- lxcDomainAttachDeviceFlags, both LIVE and CONFIG.
The check is done using the virDomainDefHasDeviceAddress, a generic
function that can check address duplicates for all supported device
types, not limiting just to DeviceDisk type.
After this patch, this is the result of the previous attach-device call:
$ ./run tools/virsh attach-device ub1810 hp-disk-dup.xml
error: Failed to attach device from hp-disk-dup.xml
error: Requested operation is not valid: Domain already contains a device with the same address
Reported-by: Srikanth Aithal <bssrikanth@in.ibm.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
This functions tries to add a domain moment (love the name!) onto
a list of domain moments. Firstly, it checks if another moment
with the same name already exists. Then, it creates an empty
moment (without initializing its definition) and tries to add the
moment onto the list dereferencing moment definition in that
process. If it succeeds (which it never can), only after that it
sets moment->def.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Commit 3bd4ed46 introduced this element as required which
breaks backcompat for test driver. Let's make the element optional.
Reviewed-by: Erik Skultety <eskultet@redhat.com>
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
Commit d1a7c08eb changed filter instantiation code to ignore MAC and IP
variables explicitly specified for filter binding. It just replaces
explicit values with values associated with the binding. Before the
commit virNWFilterCreateVarsFrom was used so that explicit value
take precedence. Let's bring old behavior back.
This is useful. For example if domain has two interfaces it makes
sense to list both mac adresses in MAC var of every interface
filterref. So that if guest make a bond of these interfaces
and start sending frames with one of the mac adresses from
both interfaces we can pass outgress traffic from both
interfaces too.
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
Now that the generic moment code does pretty much everything that both
snapshots and checkpoints will need, it's time to replace the
now-duplicate code in virdomainsnapshotobjlist.c with simpler calls
into the generic code. I considered using sub-classing (a
'virDomainMomentObjList parent;' member, but that requires making the
opaque type visible in headers; so for now, I stuck with a container
instead (a 'virDomainMomentObjListPtr base;' member).
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
The new code here very heavily resembles the code in
virDomainSnapshotObjList. There are still a couple of spots that are
tied a little too heavily to snapshots (the free function lacks a
polymorphic cleanup until we refactor code to use virObject; and an
upcoming patch will add internal VIR_DOMAIN_MOMENT_LIST flags to
replace the snapshot flag bits), but in general this is fairly close
to the state needed to add checkpoint lists.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Now that we have made virDomainMomentObj sufficiently generic to
support both snapshots and checkpoints, it is time to rename the file
that it lives in. The split between a generic object and a list of the
generic objects doesn't buy us as much, so it will be easier to stick
all the moment list code in one file, with more code moving in the
next patch. The changes during the move are fairly minor, although it
is worth pointing out that the log/error messages for the new file
report that they are from "domain", since the file will eventually be
shared by both "domain snapshot" and "domain checkpoint".
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Now that the core of SnapshotObj is agnostic to snapshots and can be
shared with upcoming checkpoint code, it is time to rename the struct
and the functions specific to list operations. A later patch will
shuffle which file holds the common code. This is a fairly mechanical
patch.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Another step towards making the object list reusable for both
snapshots and checkpoints: the list code only ever needs items that
are in the common virDomainMomentDef base type. This undoes a lot of
the churn in accessing common members added in the previous patch, and
the bulk of the patch is mechanical. But there was one spot where I
had to unroll a VIR_STEAL_PTR to work around changed types.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Pull out the common parts of virDomainSnapshotDef that will be reused
for virDomainCheckpointDef into a new base class. Adjust all callers
that use the direct fields (some of it is churn that disappears when
the next patch refactors virDomainSnapshotObj; oh well...).
Someday, I hope to switch this type to be a subclass of virObject, but
that requires a more thorough audit of cleanup paths, and besides
minimal incremental changes are easier to review.
As for the choice of naming:
I promised my teenage daughter Evelyn that I'd give her credit for her
contribution to this commit. I asked her "What would be a good name
for a base class for DomainSnapshot and DomainCheckpoint". After
explaining what a base class was (using the classic OOB Square and
Circle inherit from Shape), she came up with "DomainMoment", which is
way better than my initial thought of "DomainPointInTime" or
"DomainPIT".
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Separate the algorithm for which list members to vist (which is
generic and can be shared with checkpoints, provided that common
filtering bits are either declared with the same value or have a
mapping from public API to common value) from the decision on which
members to return (which is specific to snapshots). The typedef for
the callback function feels a bit heavy here, but will make it easier
to move the common portions in a later patch.
As part of the refactoring, note that the macros for selecting filter
bits are specific to listing functionality, so they belong better in
virdomainsnapshotobjlist.h (missed in commit 9b75154c).
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
An upcoming patch will rework virDomainSnapshotObjList to be generic
for both snapshots and checkpoints; reduce the churn by adding a new
accessor virDomainSnapshotObjGetDef() which returns the
snapshot-specific definition even when the list is rewritten to
operate only on a base class, then using it at sites that that are
specific to snapshots. Use VIR_STEAL_PTR when appropriate in the
affected lines.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Rather than allowing a leaky abstraction where multiple drivers have
to open-code operations that update the relations in a
virDomainSnapshotObjList, it is better to add accessor functions so
that updates to relations are maintained closer to the internals.
This patch finishes the job started in the previous patch, by getting
rid of all direct access to nchildren, first_child, or sibling outside
of the lowest level functions, making it easier to refactor later on.
The lone new caller to virDomainSnapshotObjListSize() checks for a
return != 0, because it wants to handles errors (-1, only possible if
the hash table wasn't allocated) and existing snapshots (> 0) in the
same manner; we can drop the check for a current snapshot on the
grounds that there shouldn't be one if there are no snapshots.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Rather than allowing a leaky abstraction where multiple drivers have
to open-code operations that update the relations in a
virDomainSnapshotObjList, it is better to add accessor functions so
that updates to relations are maintained closer to the internals.
This patch starts the task with a single new function:
virDomainSnapshotMoveChildren(). The logic might not be immediately
obvious [okay, that's an understatement - the existing code uses black
magic ;-)], so here's an overview: The old code has an implicit for
loop around each call to qemuDomainSnapshotReparentChildren() by using
virDomainSnapshotForEachChild() (you'll need a wider context than
git's default of 3 lines to see that); the new code has a more visible
for loop. Then it helps if you realize that the code is making two
separate changes to each child object: STRDUP of the new parent name
prior to writing XML files (unchanged), and touching up the pointer to
the parent object (refactored); the end result is the same whether a
single pass made both changes (both in driver code), or whether it is
split into two passes making one change each (one in driver code, the
other in the new accessor).
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
It is easier to track the current snapshot as part of the list of
snapshots. In particular, doing so lets us guarantee that the current
snapshot is cleared if that snapshot is removed from the list (rather
than depending on the caller to do so, and risking a use-after-free
problem, such as the one recently patched in 1db9d0efbf). This
requires the addition of several new accessor functions, as well as a
useful return type for virDomainSnapshotObjListRemove(). A few error
handling sites that were previously setting vm->current_snapshot =
NULL can now be dropped, because the previous function call has now
done it already. Also, qemuDomainRevertToSnapshot() was setting the
current vm twice, so keep only the one used on the success path.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Rework the logic in qemuDomainSnapshotLoad() to set
vm->current_snapshot only once at the end of the loop, rather than
repeatedly querying it during the loop, to make it easier for the next
patch to use accessor functions rather than direct manipulation of
vm->current_snapshot. When encountering multiple snapshots claiming
to be current (based on the presence of an <active>1</active> element
in the XML, which libvirt only outputs for internal use and not for
any public API), this changes behavior from warning only once and
running with no current snapshot, to instead warning on each duplicate
and selecting the last one encountered (which is arbitrary based on
readdir() ordering, but actually stands a fair chance of being the
most-recently created snapshot whether by timestamp or by the
propensity of humans to name things in ascending order).
Note that the code in question is only run by libvirtd when it first
starts, reading state from disk from the previous run into memory for
this run. Since the data resides somewhere that only libvirt should be
touching (typically /var/lib/libvirt/qemu/snapshot/*), it should be
clean. So in the common case, the code touched here is unreachable.
But if someone is actually messing with files behind libvirt's back,
they deserve the change in behavior.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
The only use for the 'current' member of virDomainSnapshotDef was with
the PARSE/FORMAT_INTERNAL flag for controlling an internal-use
<active> element marking whether a particular snapshot definition was
current, and even then, only by the qemu driver on output, and by qemu
and test driver on input. But this duplicates vm->snapshot_current,
and gets in the way of potential simplifications to have qemu store a
single file for all snapshots rather than one file per snapshot. Get
rid of the member by adding a bool* parameter during parse (ignored if
the PARSE_INTERNAL flag is not set), and by adding a new flag during
format (if FORMAT_INTERNAL is set, the value printed in <active>
depends on the new FORMAT_CURRENT).
Then update the qemu driver accordingly, which involves hoisting
assignments to vm->current_snapshot to occur prior to any point where
a snapshot XML file is written (although qemu kept
vm->current_snapshot and snapshot->def_current in sync by the end of
the function, they were not always identical in the middle of
functions, so the shuffling gets a bit interesting). Later patches
will clean up some of that confusing churn to vm->current_snapshot.
Note: even if later patches refactor qemu to no longer use
FORMAT_INTERNAL for output (by storing bulk snapshot XML instead), we
will always need PARSE_INTERNAL for input (because on upgrade, a new
libvirt still has to parse XML left from a previous libvirt).
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
When a future patch converts virDomainSnapshotDef to be a virObject,
we need to be careful that converting VIR_FREE() to virObjectUnref()
does not result in double frees. Reorder the assignment of def into
the object to the point after object is in the hash table (as
otherwise the virHashAddEntry() error path would have a shot at
freeing def prematurely).
Suggested-by: John Ferlan <ferlan@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Change the return value of virDomainSnapshotObjListParse() to return
the number of snapshots imported, and allow a return of 0 (the
original proposal of adding a flag to virDomainSnapshotCreateXML
required returning an arbitrary non-NULL snapshot, but that idea was
abandoned; and by returning a count, we are no longer constrained to a
non-empty list).
Document which flags are supported (namely, just SECURE) in
virDomainSnapshotObjListFormat().
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
An upcoming patch will be reworking virDomainSnapshotDef to have a
base class; minimize the churn by using a local variable to reduce the
number of dereferences required when acessing the domain definition
associated with the snapshot.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
And adjust virQEMUCapsSetList to use it. It will also be used in future
patches.
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
The following virsh command was triggering a use-after-free:
$ virsh -c test:///default '
snapshot-create-as test s1
snapshot-create-as test s2
snapshot-delete --children-only test s1
snapshot-current --name test'
Domain snapshot s1 created
Domain snapshot s2 created
Domain snapshot s1 children deleted
error: name in virGetDomainSnapshot must not be NULL
I got lucky on that run - although the error message is quite
unexpected. On other runs, I was able to get a core dump, and
valgrind confirms there is a definitive problem.
The culprit? We were inconsistent about whether we set
vm->current_snapshot, snap->def->current, or both when updating how
the current snapshot was being tracked. As a result, deletion did not
see that snapshot s2 was previously current, and failed to update
vm->current_snapshot, so that the next API using the current snapshot
failed because it referenced stale memory for the now-gone s2 (instead
of the intended s1).
The test driver code was copied from the qemu code (which DOES track
both pieces of state everywhere), but was purposefully simplified
because the test driver does not have to write persistent snapshot
state to the file system. But when you realize that the only reason
snap->def->current needs to exist is when writing out one file per
snapshot for qemu, it's just as easy to state that the test driver
never has to mess with the field (rather than chasing down which
places forgot to set the field), and have vm->current_snapshot be the
sole source of truth in the test driver.
Ideally, I'd get rid of the 'current' member in virDomainSnapshotDef,
as well as the 'current_snapshot' member in virDomainDef, and instead
track the current member in virDomainSnapshotObjList, coupled with
writing ALL snapshot state for qemu in a single file (where I can use
<snapshots current='...'> as a wrapper, rather than
VIR_DOMAIN_SNAPSHOT_FORMAT_INTERNAL to output <current>1</current> XML
on a per-snapshot file basis). But that's a bigger change, so for now
I'm just patching things to avoid the test driver segfault.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=1686927
When trying to create a nwfilter binding via
nwfilterBindingCreateXML() we may encounter a crash. The sequence
of functions called is as follows:
1) nwfilterBindingCreateXML() parses the XML and calls
virNWFilterBindingObjListAdd() which calls
virNWFilterBindingObjListAddLocked()
2) Here, @binding is not found because binding->remove is set.
3) Therefore, controls continue with creating new @binding,
setting its def to the one from 1) and adding it to the hash
table.
4) This fails, because the binding is still in the hash table
(duplicate key is detected).
5) The control jumps to 'error' label where
virNWFilterBindingObjEndAPI() is called which frees the binding
definition passed.
6) Error is propagated to the caller, which calls
virNWFilterBindingDefFree() over the definition again.
The solution is to unset binding->def in case of failure so it's
not freed in step 5).
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Storage source private data can be parsed along with other components of
private data rather than a separate function which is called from
multiple places.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
virDomainDiskSourcePrivateDataParse and virDomainDiskSourcePRParse don't
need the 'cleanup' label any more thanks to VIR_XPATH_NODE_AUTORESTORE.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The function does not have any code in the 'cleanup' label so we can
simplify the control flow.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
We can use our VIR_AUTOPTR machinery also for libxml2's xmlDoc and
xmlXPathContext.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
In a1c453dc08, during VIR_AUTOFREE() rewrite this wasn't done
properly. @port might be leaked because it's allocated in a for()
loop.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
In 669018bc9c I've introduced def->refresh which might be
allocated by virStoragePoolDefRefreshParse() but is never freed.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
The refresh_volume_allocation variable in
virStoragePoolDefParseXML() has been unused since its
introduction in commit 669018bc9c, and Clang rightfully
complains about this fact.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Use the new refresh volume allocation pool override to skip
computing the actual volume usage if disabled.
Signed-off-by: Jason Dillaman <dillaman@redhat.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
The new 'refresh' element can override the default refresh operations
for a storage pool. The only currently supported override is to set
the volume allocation size to the volume capacity. This can be specified
by adding the following snippet:
<pool>
...
<refresh>
<volume allocation='capacity'/>
</refresh>
...
</pool>
This is useful for certain backends where computing the actual allocation
of a volume might be an expensive operation.
Signed-off-by: Jason Dillaman <dillaman@redhat.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
The librbd API will transparently revert to a slow disk usage
calculation method if the fast-diff map is marked as invalid.
Signed-off-by: Jason Dillaman <dillaman@redhat.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
The unprivileged libvirtd does not have permission to create firewall
rules, or bridge devices, or do anything to the host network in
general. Historically we still activate the network driver though and
let the network start API call fail.
The startup code path which reloads firewall rules on active networks
would thus effectively be a no-op when unprivileged as it is impossible
for there to be any active networks
With the change to use a global set of firewall chains, however, we now
have code that is run unconditionally.
Ideally we would not register the network driver at all when
unprivileged, but the entanglement with the virt drivers currently makes
that impractical. As a temporary hack, we just make the firewall reload
into a no-op.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
During startup libvirtd creates top level chains for both ipv4
and ipv6 protocols. If this fails for any reason then startup
of virtual networks is blocked.
The default virtual network, however, only requires use of ipv4
and some servers have ipv6 disabled so it is expected that ipv6
chain creation will fail. There could equally be servers with
no ipv4, only ipv6.
This patch thus makes error reporting a little more fine grained
so that it works more sensibly when either ipv4 or ipv6 is
disabled on the server. Only the protocols that are actually
used by the virtual network have errors reported.
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
During startup we create some top level chains in which all
virtual network firewall rules will be placed. The upfront
creation is done to avoid slowing down creation of individual
virtual networks by checking for chain existance every time.
There are some factors which can cause this upfront creation
to fail and while a message will get into the libvirtd log
this won't be seen by users who later try to start a virtual
network. Instead they'll just get a message saying that the
libvirt top level chain does not exist. This message is
accurate, but unhelpful for solving the root cause.
This patch thus saves any error during daemon startup and
reports it when trying to create a virtual network later.
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The rbd_list method has been deprecated in Ceph >= 14.0.0
in favour of the new rbd_list2 method which populates an
array of structs.
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The rbd_list method has a quite unpleasant signature returning an
array of strings in a single buffer instead of an array. It is
being deprecated in favour of rbd_list2. To maintain clarity of
code when supporting both APIs in parallel, split the rbd_list
code out into a separate method.
In splitting this we now honour the rbd_list failures.
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
After this, newly added enums will not automatically show up in
driver output unless the driver code specifically sets report=true
Acked-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
Set report=true for all enums currently formatted in the XML
Acked-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
Set report=true for all enums currently formatted in the XML
Acked-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
Set report=true for all enums currently formatted in the XML
Acked-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
virCapsEnum report is an internal bool indicating whether we
should format the enum in the XML at all. This is unused for
now but will be handled in future patches.
We use a plain bool instead of tristate because the case here
is a bit different than the explicit @supported output. We
already report the equivalent of supported=YES|NO based on
what enum values are filled in. This adds report=false to
handle the ABSENT case.
Acked-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
Change domcaps to skip formatting XML if the default
TRISTATE_BOOL_ABSENT is found. Now when domcaps is extended, driver
XML output won't change until an explicit TRISTATE_BOOL value is set
in driver code.
Acked-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
<hostdev> and <features> are not supported. <loader>, <graphics>,
and <video> are supported conditionally
Acked-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
None of the <feature> bits are supported, and the <loader> piece
is only conditionally supported
Acked-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
Only gic->supported needs an explicit BOOL_NO setting, all other
'supported' values are handling things correctly
Acked-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
Switch most 'supported' handling to use virTristateBool, so eventually
we can handle the ABSENT state.
For now the XML formatter treats ABSENT the same as FALSE, so there's
no functional output change. This will be addressed in later patches
Acked-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
Similar to the macros we have for formatting enums, add a macro to
simplify formatting the pattern:
<FOO supported='yes|no'/>
Acked-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
In 0eca80e60 _class was renamed to klass for variety of struct
members. However, gather_usb_cap() was missed out in this rename
leaving FreeBSD build broken.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
This code originates from:
commit d0aa10fdd6
Author: Daniel P. Berrange <berrange@redhat.com>
Date: Tue Mar 3 12:03:44 2009 +0000
QEMU security driver usage for sVirt support (James Morris, Dan Walsh, Daniel Berrange)
Originally in the qemudDomainGetSecurityLabel function. It doesn't
appear to have done anything useful back then either. The other two
instances look like copy+paste
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
In d16f803d78 we've tried to solve an issue that after wiping an
image its format might have changed (e.g. from qcow2 to raw) but
libvirt wasn't probing the image format. We fixed this by calling
virStorageBackendRefreshVolTargetUpdate() which is what
refreshPool() would end up calling. But this shortcut is not good
enough because the function is called only for local types of
volumes (like dir, fs, netfs). But now that more backends support
volume wiping we have to call the function with more caution.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
So far we have two branches: either we zero BLOCK_PER_PACKET
(currently 128) block at once, or if we're close to the last block
then we zero out one block at the time. This is very suboptimal.
We know how many block are there left. Might as well just write
them all at once.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
This info can be useful to filter devices visible
to mgmt clients so that they won't see devices that
unsafe/not meaningful to pass thru.
Provide class info the way it is provided by udev or
kernel that is as single 6-digit hexadecimal.
Class element is not optional. I guess this should not
break users that use virNodeDeviceCreateXML because
they probably specify only scsi_host capability on
input and then node device driver gets other capabilities
from udev after device appeared.
HAL driver does not get support for the new element in
this patch.
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Vim treats *.h files as cpp ones with respect to syntax highlighting.
Thus "class" in _virNodeDevCapPCIDev highlighted mistakenly.
This can be fixed by filetype detection code tunables but it
is more convinient to skip this tuning by every project member.
Let's just use "klass" as field name instead of _class or class
and add syntax rule.
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Commit [1] moved snapshot list functions declaration into
its own file but missed a fix for vz driver.
[1] 9b75154c : snapshot: Break out virDomainSnapshotObjList into its own file
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
If pool refresh failed, then the internal table of volumes is
probably left in inconsistent or incomplete state anyways. Clear
it out then. This has an advantage that we can move the
virStoragePoolObjClearVols() from those very few backends that
do call it.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
This is a wrapper over refreshPool() call as at all places we are
doing basically the same. Might as well have a single function to
call.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
In bf5cf610f2 I've fixed a problem where iscsi-direct
backend was reporting only the last LUN. The fix consisted of
moving virStoragePoolObjClearVols() one level up. However, as it
turns out, storage driver already calls it before calling
refreshPool callback (which is
virStorageBackendISCSIDirectRefreshPool() in this case).
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
If virStorageBackendISCSIDirectVolWipeZero() fails, it has
already reported an error which is probably specific enough. Do
not overwrite it with some generic one.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
This function reports error for one of the two error paths. This
is unfortunate as a caller see this function failing but doesn't
know right away if an error was reported.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Despite the misleading name, these were supposed to be used
with a System V style init; however, none of the platforms we
target is using that kind of init anymore: almost all Linux
distributions have switched to systemd, those that haven't
(such as Gentoo and Alpine) are mostly using OpenRC with
custom init scripts, and the BSDs have been doing their own
thing all along.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Not a single one of the platforms we target still uses Upstart, and
the Upstart project itself has been abandoned for several years now.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
snapshot_conf.h was mixing three separate types: the snapshot
definition, the snapshot object, and the snapshot object list.
Separate out the snapshot object list code into its own file, and
update includes for affected clients.
This is just code motion, but done in preparation of sharing a lot of
the object list code with checkpoints.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The next patch will require access to the helper functions
virDomainSnapshotDefFormatInternal and
virDomainSnapshotRedefineValidate from two different files; make the
file split easier by exporting these functions.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
snapshot_conf.h was mixing three separate types: the snapshot
definition, the snapshot object, and the snapshot object list.
Separate out the snapshot object code into its own file, which
includes moving a typedef to avoid circular inclusions.
Mostly straight code motion, although I fixed a comment along
the way, now that virDomainSnapshotForEachDescendent now
guarantees a topological visit (missed in b647d219).
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
It's easier to locate a typedef if they are stored in sorted order;
do so mechanically via:
$ sed -i '/typedef struct/ {N; N; s/\n//g}' src/conf/virconftypes.h
$ # sorting the lines
$ sed -i '/typedef struct/ s/;/;\n/g' src/conf/virconftypes.h
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
As explained in the previous patch, collecting pointer typedefs into a
common header makes it easier to avoid circular inclusions. Continue
the efforts by pulling the appropriate typedefs from capabilities.h
into the new header.
This patch is just straight code motion (all typedefs are listed in
the same order before and after the patch); a later patch will sort
things for legibility.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Right now, snapshot_conf.h is rather large - it deals with three
separate types: virDomainSnapshotDef (the snapshot definition as it
maps to XML), virDomainSnapshotObj (an object containing a def and the
relationship to other snapshots), and virDomainSnapshotObjList (a list
of snapshot objects), where two of the three types are currently
public rather than opaque. What's more, the types are circular: a
snapshot def includes a virDomainPtr, which contains a snapshot list,
which includes a snapshot object, which includes a snapshot def.
In order to split the three objects into separate files, while still
allowing each header to use sane typedefs to incomplete pointers, the
obvious solution is to lift the typedefs into yet another header, with
no other dependencies. Start the split by factoring out all struct
typedefs from domain_conf.h (enum typedefs don't get used in function
signatures, and function typedefs tend not to suffer from circular
referencing, so those stay put). The only other exception is
virDomainStateReason, which is only ever used directly rather than via
a pointer.
This patch is just straight code motion (all typedefs are listed in
the same order before and after the patch); a later patch will sort
things for legibility.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Checking that the derived class is larger than the requested parent
class saves us from some obvious mistakes, but as written, it does not
catch all the cases; in particular, it is easy to forget to update a
VIR_CLASS_NEW when changing the 'parent' member from virObject to
virObjectLockabale, but where the size checks don't catch that. Add a
parameter for one more layer of sanity checking.
It would be cool if we could get gcc to stringize typeof(parent) into
the string name of that type, so that we could confirm that the
precise parent class is in use rather than just a struct that happens
to have the same size as the parent class. But sizeof checks are
better than nothing.
Note that I did NOT change the fact that we require derived classes to
be larger (as the difference in size makes it easy to tell classes
apart), which means that even if a derived class has no functionality
to add (but rather exists for compiler-enforced type-safety), it must
still include a dummy member. But I did fix the wording of the error
message to match the code.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
By default, qemu user's home dir points to '/' which shouldn't be used
at all. We therefore pass the HOME variable from the current variable
iff not running as SUID, which means that for systemd we never set it.
This patch makes sure, that for system QEMU this is always set to
libDir/<driver>, session mode is left untouched.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
For session mode, only XDG_CACHE_HOME is set, because we want to remain
integrating with services in user session, but for system mode, this
would have become reading/writing to '/' which carries the obvious issue
with permissions (also, '/' is the wrong location in 99.9% cases anyway).
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Some modules/libraries within QEMU could make use of the XDG_ vars when
writing their data to the disk. Define the most common XDG variables
and point them to the specific driver's libDir, i.e.
XDG_CACHE_HOME -> /var/lib/libvirt/<driver>/.cache
XDG_DATA_HOME -> /var/lib/libvirt/<driver>/.local/share
XDG_CONFIG_HOME -> /var/lib/libvirt/<driver>/.config
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
The functions do basically exactly the same thing modulo few checks.
In case of virtio disks we check that the device is not multifunction as
that can't be unplugged at once. In case of USB and SCSI disks we
checked that no active block job is running.
The check for running blockjobs should have also been done for virtio
disks. By moving the multifunction check into the common function we fix
this case and also simplify the code.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Use the correct type in switch and populate the missing cases.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
We don't have any cleanup section, we can return the value directly.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Based on recent list questions about the proposed addition of
virDomainCheckpointCreateXML(REDEFINE), it is worth adding some
clarification to the existing snapshot redefine documentation that is
serving as the basis for checkpoints.
Normal snapshot creation requires very few elements from the user XML
(libvirt can pick sane defaults for items that are omitted, and many
fields, including <domain>, are documented as readonly output fields
ignored on input, produced by drivers that track it). But during
REDEFINE, the API wants the complete XML produced by an earlier
virDomainSnapshotGetXMLDesc; as the domain definition has likely
changed since the snapshot was first created, libvirt is unable to
recreate a <domain> sub-element that matches the original output
representing the domain state at the time the snapshot was first
created. In fact, reverting without a <domain> sub-element is risky
enough that we had to add a FORCE flag for virDomainSnapshotRevert().
In short, we only support omitting domain for qemu because of
backwards-compatibility to snapshots created before 0.9.5 started
capturing <domain>; even though there are other drivers like vbox that
do not output <domain> because they have other reliable ways to
revert.
And based on the confusion caused when omitting <domain> from snapshot
XML, the initial design for checkpoints in later patches will make
<domain> a mandatory element during its REDEFINE.
[Side note: the fact that <domain> can appear in <domainsnapshot> is a
reason we cannot add a new API for a bulk listing or redefine of all
snapshots of a single domain in one XML call (for example, a 1M
<domain> XML * 16 snapshots explodes into 16M in a bulk form, which
gets difficult to send over RPC). Perhaps we could add a flag to
request that the <domain> sub-element be omitted on output, but such
output is no longer suitable for sane REDEFINE input.]
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
