block: Add bdrv_next_node

Similar to bdrv_next, this traverses through graph_bdrv_states. Will be
useful to enumerate all the named nodes.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
block: Add bdrv_get_node_name

This returns the node name of a BDS. Remove the TODO comment and expect
the callers to be explicit.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
block: Include "node-name" if present in query-blockstats

Node name is a better identifier of BDS.

We will want to query statistics of a BDS node buried in the BDS graph,
so reporting the node's name if there is one will do the trick.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
qmp: Add optional switch "query-nodes" in query-blockstats

This bool option will allow query all the node names. It iterates all
the BDSes that are assigned a name, also in this case don't query up the
backing chain.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
chardev: Add -qmp-pretty

Add a command line option for adding a QMP monitor using pretty JSON
formatting.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
iotests: _filter_qmp for pretty JSON output

_filter_qmp should be able to correctly filter out the QMP version
object for pretty JSON output.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
iotests: Use -qmp-pretty in 067

067 invokes query-block, resulting in a reference output with really
long lines (which may pose a problem in email patches and always poses a
problem when the output changes, because it is hard to see what has
actually changed). Use -qmp-pretty to mitigate this issue.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
blockdev: acquire AioContext in blockdev-snapshot-delete-internal-sync

Add dataplane support to the blockdev-snapshot-delete-internal-sync QMP
command.  By acquiring the AioContext we avoid race conditions with the
dataplane thread which may also be accessing the BlockDriverState.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
blockdev: check for BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE

The BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE op blocker exists but was
never used!  Let's fix that so snapshot delete can be blocked.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
blockdev: acquire AioContext in eject, change, and block_passwd

By acquiring the AioContext we avoid race conditions with the dataplane
thread which may also be accessing the BlockDriverState.

Fix up eject, change, and block_passwd in a single patch because
qmp_eject() and qmp_change_blockdev() both call eject_device().  Also
fix block_passwd while we're tackling a command that takes a block
encryption password.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
blockdev: acquire AioContext in change-backing-file

Add dataplane support to the change-backing-file QMP commands.  By
acquiring the AioContext we avoid race conditions with the dataplane
thread which may also be accessing the BlockDriverState.

Note that this command operates on both bs and a node in its chain
(image_bs).  The bdrv_chain_contains(bs, image_bs) check guarantees that
bs and image_bs are in the same AioContext.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>