BlockdevRef is an alternate of BlockdevOptions (inline definition) and
str (reference to an existing block device by name). BlockdevRef
value "" is special: "no block device should be referenced." It's
actually interpreted that way in just one place: optional member
@backing of COW formats. Semantics:
* Present means "use this block device" as backing storage
* Absent means "default to the one stored in the image"
* Except "" means "don't use backing storage at all"
The first two are perfectly normal: when the parameter is absent, it
defaults to an implied value, but the value's meaning is the same.
The third one overloads the parameter with a second meaning. The
overloading is *implicit*, i.e. it's not visible in the types. Works
here, because "" is not a value block device ID.
Pressing argument values the schema accepts, but are semantically
invalid, into service to mean "do something else entirely" is not
general, as suitable invalid values need not exist. I also find it
ugly.
To clean this up, we could add a separate flag argument to suppress
@backing, or add a distinct value to @backing. This commit implements
the latter: add JSON null to the values of @backing, deprecate "".
Because we're so close to the 2.10 freeze, implement it in the
stupidest way possible: have qmp_blockdev_add() rewrite null to ""
before anything else can see the null. Works, because BlockdevRef
occurs only within arguments of blockdev-add. The proper way to do it
would be rewriting "" to null, preferably in a cleaner way, but that
requires fixing up code to work with null. Add a TODO comment for
that.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Acked-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Or, rather, force the open of a backing image if one was specified
for creation. Using a similar -unsafe option as rebase, allow qemu-img
to ignore the backing file validation if possible.
It may not always be possible, as in the existing case when a filesize
for the new image was not specified.
This is accomplished by shifting around the conditionals in
bdrv_img_create, such that a backing file is always opened unless we
provide BDRV_O_NO_BACKING. qemu-img is adjusted to pass this new flag
when -u is provided to create.
Sorry for the heinous looking diffstat, but it's mostly whitespace.
Inspired by: https://bugzilla.redhat.com/show_bug.cgi?id=1213786
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In the case where we test the expected error when a blockdev-snapshot
target already has a backing image, the backing chain is opened multiple
times. This will be a problem when we use image locking, so use a
different backing file that is not already open.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Now that QAPI supports boxed types, we can have unions at the top level
of a command, so let's put our real options directly there for
blockdev-add instead of having a single "options" dict that contains the
real arguments.
blockdev-add is still experimental and we already made substantial
changes to the API recently, so we're free to make changes like this
one, too.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
This test checks that it is not possible to create a snapshot if the
requested overlay node is a BDS which does not support backing images.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch removes the inner quotation marks in all cases like this:
cmd=" ... "${variable}" ... "
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The new functionality of common.qemu implements the QEMU control
and communication functionality that was originally in test 085.
This removes that now-duplicate functionality, and uses the
common.qemu functions.
The QEMU commandline changes slightly due to this; in addition to
monitor and qmp i/o options, the new QEMU commandline from inside
common.qemu now introduces -machine accel=qtest.
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This adds tests for live snapshots, both through the single
snapshot command, and the transaction group snapshot command.
The snapshots are done through the QMP interface, using the
following commands for snapshots:
Single snapshot:
{ 'execute': 'blockdev-snapshot-sync', 'arguments':
{ 'device': 'virtio0', 'snapshot-file':'...',
'format': 'qcow2' } }"
Group snapshot:
{ 'execute': 'transaction', 'arguments':
{'actions': [
{ 'type': 'blockdev-snapshot-sync', 'data' :
{ 'device': 'virtio0', 'snapshot-file': '...' } },
{ 'type': 'blockdev-snapshot-sync', 'data' :
{ 'device': 'virtio1', 'snapshot-file': '...' } } ]
} }
Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
