Add entries for deprecation_behavior, improving of errors from virsh's
snapshot helpers and other bugfixes.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
---
 NEWS.rst | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/NEWS.rst b/NEWS.rst
index 5f8b0ae02d..4a5e2c9fd4 100644
--- a/NEWS.rst
+++ b/NEWS.rst
@@ -18,10 +18,58 @@ v7.3.0 (unreleased)
     The xen driver now supports domains with more than 4TB of memory with
     xen >= 4.13.

+  * qemu: Allow use of qemu's ``-compat`` option
+
+    Curious developers or testers now can enable certain ``-compat`` modes which
+    allow to notice use of deprecated commands and options as qemu will use the
+    selected method to notify the user. The new behaviour can be requested using
+    either the ``deprecation_behavior`` option in ``qemu.conf`` for all VMs or
+    using ``<qemu:deprecation behavior='...'/>`` in the VM XML.
+
 * **Improvements**

+  * virsh: Improve errors with ``virsh snapshot-create-as``
+
+    The XML constructed by virsh was forced through RNG schema validation which
+    yielded unintelligible error messages in cases such as when the path to
+    the new image was not starting with a slash. XMLs are no longer validated
+    as the XML parser actually has better error messages which allow users to
+    figure the problem out quickly.
+
+  * qemu: Terminate backing store when doing a full-chain block pull
+
+    When pulling everything into the overlay image the chain can be terminated
+    since we know that it won't depend on any backing image and thus can prevent
+    attempts to probe the backing chain.
+
 * **Bug fixes**

+  * qemu: Fix crash of libvirt on full block pull of a disk
+
+    When the persistent definition contains a compatible disk (meaning the
+    definition of the running and persistent config match) a block pull job
+    would leave a dangling pointer in the config definition which resulted
+    in a crash.
+
+  * qemu: Use proper job cancelling command
+
+    Libvirt's API contract for aborting a block copy job in 'ready' state
+    declares that the destination image of the copy will contain a consistent
+    image of the disk from the time when the block job was aborted. This
+    requires that libvirt uses the proper cancelling qemu command to ensure
+    that the data is consistent which was not the case.
+
+  * qemu: Don't attempt storage migration when there are no migratable disks
+
+    Due to a logic bug introduced in the previous release libvirt would attempt
+    to migrate disks in case when no disks are selected/eligible for migration.
+
+  * qemu: Fix very rare race when two block job 'ready' events are delivered
+
+    In certain high-load scenarios, qemu might deliver the 'ready' event twice
+    and if it's delivered when pivoting to the destination during a block copy
+    job, libvirt would get confused and execute the code as if the job were
+    aborted.

 v7.2.0 (2021-04-01)
 ===================
-- 
2.30.2

On Tue, 2021-04-27 at 15:37 +0200, Peter Krempa wrote:
> Add entries for deprecation_behavior, improving of errors from
> virsh's
> snapshot helpers and other bugfixes.
> 
> Signed-off-by: Peter Krempa <pkrempa@redhat.com>
> ---
>  NEWS.rst | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 48 insertions(+)
> 
> diff --git a/NEWS.rst b/NEWS.rst
> index 5f8b0ae02d..4a5e2c9fd4 100644
> --- a/NEWS.rst
> +++ b/NEWS.rst
> @@ -18,10 +18,58 @@ v7.3.0 (unreleased)
>      The xen driver now supports domains with more than 4TB of memory
> with
>      xen >= 4.13.
> 
> +  * qemu: Allow use of qemu's ``-compat`` option
> +
> +    Curious developers or testers now can enable certain ``-compat`` 
> modes which
> +    allow to notice use of deprecated commands and options as qemu
> will use the
> +    selected method to notify the user. The new behaviour can be
> requested using
> +    either the ``deprecation_behavior`` option in ``qemu.conf`` for
> all VMs or
> +    using ``<qemu:deprecation behavior='...'/>`` in the VM XML.
> +
>  * **Improvements**
> 
> +  * virsh: Improve errors with ``virsh snapshot-create-as``
> +
> +    The XML constructed by virsh was forced through RNG schema
> validation which

I initially read that as "Random Number Generator schema validation"
and was a bit confused. Just FYI.

> +    yielded unintelligible error messages in cases such as when the
> path to
> +    the new image was not starting with a slash.

Perhaps change "was not starting with" to "did not start with"

>  XMLs are no longer validated

Personal nit: XMLs technically expands to Extensible Markup Languages,
which sounds a bit off to my ears. I prefer something like "XML files"

> +    as the XML parser actually has better error messages which allow
> users to
> +    figure the problem out quickly.
> +
> +  * qemu: Terminate backing store when doing a full-chain block pull
> +
> +    When pulling everything into the overlay image the chain can be
> terminated
> +    since we know that it won't depend on any backing image and thus
> can prevent
> +    attempts to probe the backing chain.
> +
>  * **Bug fixes**
> 
> +  * qemu: Fix crash of libvirt on full block pull of a disk
> +
> +    When the persistent definition contains a compatible disk
> (meaning the
> +    definition of the running and persistent config match) a block
> pull job
> +    would leave a dangling pointer in the config definition which
> resulted
> +    in a crash.
> +
> +  * qemu: Use proper job cancelling command
> +
> +    Libvirt's API contract for aborting a block copy job in 'ready'
> state
> +    declares that the destination image of the copy will contain a
> consistent
> +    image of the disk from the time when the block job was aborted.
> This
> +    requires that libvirt uses the proper cancelling qemu command to
> ensure
> +    that the data is consistent which was not the case.
> +
> +  * qemu: Don't attempt storage migration when there are no
> migratable disks
> +
> +    Due to a logic bug introduced in the previous release libvirt
> would attempt
> +    to migrate disks in case when no disks are selected/eligible for
> migration.
> +
> +  * qemu: Fix very rare race when two block job 'ready' events are
> delivered
> +
> +    In certain high-load scenarios, qemu might deliver the 'ready'
> event twice
> +    and if it's delivered when pivoting to the destination during a
> block copy
> +    job, libvirt would get confused and execute the code as if the
> job were
> +    aborted.
> 
>  v7.2.0 (2021-04-01)
>  ===================


Reviewed-by: Jonathon Jongsma <jjongsma@redhat.com>

On Tue, Apr 27, 2021 at 09:12:01 -0500, jjongsma@redhat.com wrote:
> On Tue, 2021-04-27 at 15:37 +0200, Peter Krempa wrote:
> > Add entries for deprecation_behavior, improving of errors from
> > virsh's
> > snapshot helpers and other bugfixes.
> > 
> > Signed-off-by: Peter Krempa <pkrempa@redhat.com>
> > ---
> >  NEWS.rst | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 48 insertions(+)
> > 
> > diff --git a/NEWS.rst b/NEWS.rst
> > index 5f8b0ae02d..4a5e2c9fd4 100644
> > --- a/NEWS.rst
> > +++ b/NEWS.rst
> > @@ -18,10 +18,58 @@ v7.3.0 (unreleased)
> >      The xen driver now supports domains with more than 4TB of memory
> > with
> >      xen >= 4.13.
> > 
> > +  * qemu: Allow use of qemu's ``-compat`` option
> > +
> > +    Curious developers or testers now can enable certain ``-compat`` 
> > modes which
> > +    allow to notice use of deprecated commands and options as qemu
> > will use the
> > +    selected method to notify the user. The new behaviour can be
> > requested using
> > +    either the ``deprecation_behavior`` option in ``qemu.conf`` for
> > all VMs or
> > +    using ``<qemu:deprecation behavior='...'/>`` in the VM XML.
> > +
> >  * **Improvements**
> > 
> > +  * virsh: Improve errors with ``virsh snapshot-create-as``
> > +
> > +    The XML constructed by virsh was forced through RNG schema
> > validation which
> 
> I initially read that as "Random Number Generator schema validation"
> and was a bit confused. Just FYI.

Good point. I've changed it to "XML schema validation" as mentioning the
specific schema language isn't adding to the clarity.

> > +    yielded unintelligible error messages in cases such as when the
> > path to
> > +    the new image was not starting with a slash.
> 
> Perhaps change "was not starting with" to "did not start with"
> 
> >  XMLs are no longer validated
> 
> Personal nit: XMLs technically expands to Extensible Markup Languages,
> which sounds a bit off to my ears. I prefer something like "XML files"

I went with 'XML document' since we don't actually save it to a file in
this instance.