When copying to a block device, the block device will already exist. To
allow users using a block device without any preparation, they need to
use the block copy without VIR_DOMAIN_BLOCK_COPY_REUSE_EXT.

This means that if the target is an existing block device we don't need
to prepare it, but we can't reject it as being existing.

To avoid breaking this feature, explicitly assume that existing block
devices will be reused even without that flag explicitly specified,
while skipping attempts to create it.

qemuMonitorDriveMirror still needs to honor the flag as specified by the
user, since qemu overwrites the metadata otherwise.

Extract the presence of the flag into a boolean to simplify conditions
and allow further manipulation of the state of the flag.

https://bugzilla.redhat.com/show_bug.cgi?id=1467826

Commit id 'b9b1aa63' was supposed to add logic to set the allocation
for sparse files when wr_highest_offset was zero; however, an unconditional
setting was done just prior. For block devices, this means allocation is
always returning 0 since 'actual-size' will be zero.

Remove the unconditional setting and add the note about it being possible
to still be zero for block devices. As soon as the guest starts writing to
the volume, the allocation value will then be obtainable from qemu via
the wr_highest_offset.

The API documents that it peeks into the VM disk. We can't do that
currently for non raw images so report an error.

Refactor the access to storage driver usage along with
qemuDomainStorageFileInit which ensures that we access the file with
correct DAC uid/gid.

Allow specifying offset to read an arbitrary position in the file. This
warrants a rename to virStorageFileRead.

The helper methods for actually accessing the storage objects don't
really belong to the main storage driver implementation file. Split them
out.

We have a temporary pointer to the currently processed parameter.
Use it to save three bytes per use.

We assign the unsigned long value of the currently processed
parameter to a temporary value_ul variable. Use it consistently
in all cases.

If a remote call fails during event registration (more than likely from
a network failure or remote libvirtd restart timed just right), then when
calling the virObjectEventStateDeregisterID we don't want to call the
registered @freecb function because that breaks our contract that we
would only call it after succesfully returning.  If the @freecb routine
were called, it could result in a double free from properly coded
applications that free their opaque data on failure to register, as seen
in the following details:

    Program terminated with signal 6, Aborted.
    #0  0x00007fc45cba15d7 in raise
    #1  0x00007fc45cba2cc8 in abort
    #2  0x00007fc45cbe12f7 in __libc_message
    #3  0x00007fc45cbe86d3 in _int_free
    #4  0x00007fc45d8d292c in PyDict_Fini
    #5  0x00007fc45d94f46a in Py_Finalize
    #6  0x00007fc45d960735 in Py_Main
    #7  0x00007fc45cb8daf5 in __libc_start_main
    #8  0x0000000000400721 in _start

The double dereference of 'pyobj_cbData' is triggered in the following way:

    (1) libvirt_virConnectDomainEventRegisterAny is invoked.
    (2) the event is successfully added to the event callback list
        (virDomainEventStateRegisterClient in
        remoteConnectDomainEventRegisterAny returns 1 which means ok).
    (3) when function remoteConnectDomainEventRegisterAny is hit,
        network connection disconnected coincidently (or libvirtd is
        restarted) in the context of function 'call' then the connection
        is lost and the function 'call' failed, the branch
        virObjectEventStateDeregisterID is therefore taken.
    (4) 'pyobj_conn' is dereferenced the 1st time in
        libvirt_virConnectDomainEventFreeFunc.
    (5) 'pyobj_cbData' (refered to pyobj_conn) is dereferenced the
         2nd time in libvirt_virConnectDomainEventRegisterAny.
    (6) the double free error is triggered.

Resolve this by adding a @doFreeCb boolean in order to avoid calling the
freeCb in virObjectEventStateDeregisterID for any remote call failure in
a remoteConnect*EventRegister* API. For remoteConnect*EventDeregister* calls,
the passed value would be true indicating they should run the freecb if it
exists; whereas, it's false for the remote call failure path.

Patch based on the investigation and initial patch posted by
fangying <fangying1@huawei.com>.

Commit 7456c4f5 introduced a regression by not reloading the backing
chain of a disk after snapshot. The regression was caused as
src->relPath was not set and thus the block commit code could not
determine the relative path.

This patch adds code that will load the backing store string if
VIR_DOMAIN_SNAPSHOT_CREATE_REUSE_EXT and store it in the correct place
when a snapshot is successfully completed.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1461303

Calls to qemuDomainDiskChainElementPrepare resets the original error,
thus we need to save it in the cleanup path of qemuDomainBlockCommit.

Changing labelling of the images does not need to happen after setting
the labeling and lock manager access. This saves the cleanup of the
labeling if the relative path can't be determined.

Most places which want to check ABI stability for an active domain need
to call this API rather than the original
qemuDomainDefCheckABIStability. The only exception is in snapshots where
we need to decide what to do depending on the saved image data.

https://bugzilla.redhat.com/show_bug.cgi?id=1460952Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NPavel Hrdina <phrdina@redhat.com>

Commit v3.4.0-44-gac793bd7 fixed a memory leak, but failed to return
the special -3 value. Thus an attempt to start a domain with corrupted
managed save file would removed the corrupted file and report
"An error occurred, but the cause is unknown" instead of starting the
domain from scratch.

https://bugzilla.redhat.com/show_bug.cgi?id=1460962

Use ATTRIBUTE_FALLTHROUGH, introduced by commit
5d84f596, instead of comments to
indicate that the fall through is an intentional behavior.
Signed-off-by: NMarc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: NBoris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: NBjoern Walk <bwalk@linux.vnet.ibm.com>

Exiting early through the cleanup path did result in 'mirror'
being leaked.

If QEMU is new enough and we have the live updated CPU definition in
either save or migration cookie, we can use it to enforce ABI. The
original guest CPU from domain XML will be stored in private data.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NPavel Hrdina <phrdina@redhat.com>

The destination host may not be able to start a domain using the live
updated CPU definition because either libvirt or QEMU may not be new
enough. Thus we need to send the original guest CPU definition.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NPavel Hrdina <phrdina@redhat.com>

The following patches will add an actual content in the cookie and use
the data when restoring a domain.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NPavel Hrdina <phrdina@redhat.com>

The new structure encapsulates save image header and associated data
(domain XML).
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NPavel Hrdina <phrdina@redhat.com>

The function is now called virQEMUSaveDataWrite and it is now doing
everything it needs to save both the save image header and domain XML to
a file. Be it a new file or an existing file in which a user wants to
change the domain XML.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NPavel Hrdina <phrdina@redhat.com>

The function is supposed to update the save image header after a
successful migration to the save image file.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NPavel Hrdina <phrdina@redhat.com>

This is a preparation for creating a new virQEMUSaveData structure which
will encapsulate all save image header data.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NPavel Hrdina <phrdina@redhat.com>

Since virQEMUSaveHeader will be followed by more than just domain XML,
the old name would be confusing as it was designed to describe the
length of all data following the save image header.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NPavel Hrdina <phrdina@redhat.com>

This will be used later when a save cookie will become part of the
snapshot XML using new driver specific parser/formatter functions.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NPavel Hrdina <phrdina@redhat.com>

Allow starting the block-copy job for a persistent domain if a user
declares by using a flag that the job will not be recovered if the VM is
switched off while the job is active.

This allows to use the block-copy job with persistent VMs under the same
conditions as would apply to transient domains.

While checking for ABI stability, drivers might pose additional
checks that are not valid for general case. For instance, qemu
driver might check some memory backing attributes because of how
qemu works. But those attributes may work well in other drivers.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

qemuDomainGetBlockInfo would error out if qemu did not report
'wr_highest_offset'. This usually does not happen, but can happen
briefly during active layer block commit. There's no need to report the
error, we can simply report that the disk is fully alocated at that
point.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1452045

In 48d9e6cd and friends we've allowed users to back guest
memory by a file inside the host. And in order to keep things
manageable the memory_backing_dir variable was introduced to
qemu.conf to specify the directory where the files are kept.
However, libvirt's policy is that directories are created on
domain startup if they don't exist. We've missed this one.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

'param' contains the correct element from 'params'.

If the group name would not be the first parameter libvirtd would crash.

Introduced in c53bd25b.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1455510

Setting the 'group_name' for a disk would falsely trigger a error path
as in commit 4b57f765 we did not properly check the return value of
VIR_STRDUP.

priv and qemuCaps variables are not used anymore.
Signed-off-by: NKothapally Madhu Pavan <kmp@linux.vnet.ibm.com>

Since we allow active layer block commit the users are allowed to commit
the top of the chain (e.g. vda) into the backing image. The API would
not accept that parameter, as it tried to look up the image in the
backing chain.

Add the ability to use the top level image target name explicitly as the
top image of the block commit operation.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1451394

The function returns -errno on failure, not only -1.

The function is nontrivial to follow and has non-standard return values.
Recent usage was buggy.

Since commit c5f61513 qemuDomainBlockInfo tries to update the
"physical" storage size for all network storage and not only block
devices.

Since the storage driver APIs to do this are not implemented for certain
storage types (RBD, iSCSI, ...) the code would fail to retrieve any data
since the failure of qemuDomainStorageUpdatePhysical is fatal.

Since it's desired to return data even if the total size can't be
updated we need to ignore errors from that function and return plausible
data.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1442344

Not all async jobs are visible via virDomainGetJobStats (either they are
too fast or getting the stats is not allowed during the job), but
forcing all of them to advertise the operation is easier than hunting
the jobs for which fetching statistics is allowed. And we won't need to
think about this when we add support for getting stats for more jobs.

https://bugzilla.redhat.com/show_bug.cgi?id=1441563Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

Becase it can be called during migration out (namely on cancelling
blockjobs).
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>