For legibility, wrap text paragraphs so every line is at most 70
characters long.
To check the generated documentation does not change, I compared the
generated HTML before and after this commit with "wdiff -3". Finds no
differences. Comparing with diff is not useful, as the refilled
paragraphs are visible there.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240322140910.328840-11-armbru@redhat.com>
Commit a937b6aa73 (qapi: Reformat doc comments to conform to current
conventions) reflowed some text that should have been left alone.
Revert that.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240322140910.328840-4-armbru@redhat.com>
By convention, we indent the second and subsequent lines of
descriptions and tagged sections, except for examples.
Turn this into a hard rule, and apply it to examples, too.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240216145841.2099240-11-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
[Straightforward conflicts in qapi/migration.json resolved]
Since commit a937b6aa73 (qapi: Reformat doc comments to conform to
current conventions), a number of comments not conforming to the
current formatting conventions were added. No problem, just sweep
the entire documentation once more.
To check the generated documentation does not change, I compared the
generated HTML before and after this commit with "wdiff -3". Finds no
differences. Comparing with diff is not useful, as the reflown
paragraphs are visible there.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20230720071610.1096458-7-armbru@redhat.com>
Examples come out like
Example
set new histograms for all io types with intervals [0, 10), [10,
50), [50, 100), [100, +inf):
The sentence "set new histograms ..." starts with a lower case letter.
Capitalize it. Same for the other examples.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20230720071610.1096458-3-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Taking account of the new zone append write operation for zoned devices,
BLOCK_ACCT_ZONE_APPEND enum is introduced as other I/O request type (read,
write, flush).
Signed-off-by: Sam Li <faithilikerun@gmail.com>
Message-id: 20230508051916.178322-3-faithilikerun@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Change
# @name: Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed
# do eiusmod tempor incididunt ut labore et dolore magna aliqua.
to
# @name: Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed
# do eiusmod tempor incididunt ut labore et dolore magna aliqua.
See recent commit "qapi: Relax doc string @name: description
indentation rules" for rationale.
Reflow paragraphs to 70 columns width, and consistently use two spaces
to separate sentences.
To check the generated documentation does not change, I compared the
generated HTML before and after this commit with "wdiff -3". Finds no
differences. Comparing with diff is not useful, as the reflown
paragraphs are visible there.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230428105429.1687850-18-armbru@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Acked-by: Lukas Straub <lukasstraub2@web.de>
[Straightforward conflicts in qapi/audio.json qapi/misc-target.json
qapi/run-state.json resolved]
A few examples neglect to prefix QMP input with '->'. Fix that.
Two examples have extra space after '<-'. Delete it.
A few examples neglect to show output. Provide some. The example
output for query-vcpu-dirty-limit could use further improvement. Add
a TODO comment.
Use "Examples:" instead of "Example:" where multiple examples are
given.
One example section numbers its two examples. Not done elsewhere;
drop.
Another example section separates them with "or". Likewise.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20230425064223.820979-8-armbru@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Of the block device commands, those that are available outside system
emulators do not require a fully constructed machine by definition.
Allow running them before machine initialization has concluded.
Of the ones that are available inside system emulation, allow querying
the PR managers, and setting up accounting and throttling.
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Perfectly aligned things look pretty, but keeping them that
way as the schema evolves requires churn, and in some cases
newly-added lines are not aligned properly.
Overall, trying to align things is just not worth the trouble.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Message-Id: <20220503073737.84223-8-abologna@redhat.com>
Message-Id: <20220503073737.84223-9-abologna@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Two patches squashed together]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
The only instances that get changed are those in which the
additional whitespace was not (or couldn't possibly be) used for
alignment purposes.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Message-Id: <20220503073737.84223-7-abologna@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20220503073737.84223-6-abologna@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20220503073737.84223-5-abologna@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
This only affects readability. The generated documentation
doesn't change.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20220503073737.84223-4-abologna@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
'blockdev-change-medium' is a convinient wrapper for the following
sequence of commands:
* blockdev-open-tray
* blockdev-remove-medium
* blockdev-insert-medium
* blockdev-close-tray
and should be used f.e. to change ISO image inside the CD-ROM tray.
Though the guest could lock the tray and some linux guests like
CentOS 8.5 actually does that. In this case the execution if this
command results in the error like the following:
Device 'scsi0-0-1-0' is locked and force was not specified,
wait for tray to open and try again.
This situation is could be resolved 'blockdev-open-tray' by passing
flag 'force' inside. Thus is seems reasonable to add the same
capability for 'blockdev-change-medium' too.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@openvz.org>
Acked-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Hanna Reitz <hreitz@redhat.com>
CC: Eric Blake <eblake@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
Message-Id: <20220412221846.280723-1-den@openvz.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
We use x.y most of the time, and x.y.0 sometimes. Normalize for
consistency.
Reported-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20201118064158.3359056-1-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
The block-latency-histogram-set command is the only one which uses
the Example/Examples section with the first line of the documentation
immediately following the ':'. Bring it into line with the rest.
This will allow us to avoid special-casing the indentation handling
for "Examples" sections; instead for Examples as for any other section
header these two indentations will be equivalent:
Examples:
Line one
Line two
Examples: Line one
Line two
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200925162316.21205-3-peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message tweaked]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
The various schemas included in QEMU use a JSON-based format which
is, however, strictly speaking not valid JSON.
As a consequence, when vim tries to apply syntax highlight rules
for JSON (as guessed from the file name), the result is an unreadable
mess which mostly consist of red markers pointing out supposed errors
in, well, pretty much everything.
Using Python syntax highlighting produces much better results, and
in fact these files already start with specially-formatted comments
that instruct Emacs to process them as if they were Python files.
This commit adds the equivalent special comments for vim.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Message-Id: <20200729185024.121766-1-abologna@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Add feature 'deprecated' to the deprecated QMP commands, so their
deprecation becomes visible in output of query-qmp-schema. Looks like
this:
{"name": "query-cpus",
"ret-type": "[164]",
"meta-type": "command",
"arg-type": "0",
---> "features": ["deprecated"]}
Management applications could conceivably use this for static
checking.
The deprecated commands are change, cpu-add, migrate-set-cache-size,
migrate_set_downtime, migrate_set_speed, query-cpus, query-events,
query-migrate-cache-size.
The deprecated command arguments are block-commit arguments @base and
@top, and block_set_io_throttle, blockdev-change-medium,
blockdev-close-tray, blockdev-open-tray, eject argument @device.
The deprecated command results are query-cpus-fast result @arch,
query-block result @dirty-bitmaps, query-named-block-nodes result
@encryption_key_missing and result @dirty-bitmaps's member @status.
Same for query-block result @inserted, which mirrors
query-named-block-nodes.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200317115459.31821-27-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
QMP commands that are related to the system emulator and don't make
sense in the context of tools such as qemu-storage-daemon should live in
qapi/block.json rather than qapi/block-core.json. Move them there.
The associated data types are actually also used in code shared with the
tools, so they stay in block-core.json.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20200224143008.13362-6-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block-core is for everything that isn't related to the system emulator.
Internal snapshots, the NBD server and quorum events make sense in the
tools, too, so move them to block-core.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20200224143008.13362-5-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
A JSON block comment like this:
Returns: nothing on success
If @node is not a valid block device, DeviceNotFound
If @name is not found, GenericError with an explanation
renders like this:
Returns: nothing on success If node is not a valid block device,
DeviceNotFound If name is not found, GenericError with an explanation
because whitespace is not significant.
Use an actual bulleted list, so that the formatting is correct.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200213175647.17628-14-peter.maydell@linaro.org>
Message-Id: <20200213175647.17628-15-peter.maydell@linaro.org>
Message-Id: <20200213175647.17628-16-peter.maydell@linaro.org>
[Three commits squashed into one]
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
The current doc generation doesn't care much about indentation levels,
but we would like to switch to an rST format, and rST does care about
indentation.
Make the doc comments more strongly consistent about indentation
for multiline constructs like:
@arg: description line 1
description line 2
Returns: line one
line 2
so that there is always exactly one space after the colon, and
subsequent lines align with the first.
This commit is a purely whitespace change, and it does not alter the
generated .texi files (because the texi generation code strips away
all the extra whitespace). This does mean that we end up with some
over-length lines.
Note that when the documentation for an argument fits on a single
line like this:
@arg: one line only
then stray extra spaces after the ':' don't affect the rST output, so
I have not attempted to methodically fix them, though the preference
is a single space here too.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200213175647.17628-10-peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message tweaked]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Allow blockdevs to match the feature already present in qemu-nbd -D.
Enhance iotest 223 to cover it.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20191114024635.11363-5-eblake@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20190227162035.18543-4-berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
As with the previous patch to qemu-nbd, the nbd-server-start QMP command
also needs to be able to specify authorization when enabling TLS encryption.
First the client must create a QAuthZ object instance using the
'object-add' command:
{
'execute': 'object-add',
'arguments': {
'qom-type': 'authz-list',
'id': 'authz0',
'parameters': {
'policy': 'deny',
'rules': [
{
'match': '*CN=fred',
'policy': 'allow'
}
]
}
}
}
They can then reference this in the new 'tls-authz' parameter when
executing the 'nbd-server-start' command:
{
'execute': 'nbd-server-start',
'arguments': {
'addr': {
'type': 'inet',
'host': '127.0.0.1',
'port': '9000'
},
'tls-creds': 'tls0',
'tls-authz': 'authz0'
}
}
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <20190227162035.18543-3-berrange@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Now that nbd-server-add can do the same functionality (well, other
than making the exported bitmap name different than the underlying
bitamp - but we argued that was not essential, since it is just as
easy to create a new non-persistent bitmap with the desired name),
we no longer need the experimental separate command.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20190111194720.15671-7-eblake@redhat.com>
With the experimental x-nbd-server-add-bitmap command, there was
a window of time where an NBD client could see the export but not
the associated dirty bitmap, which can cause a client that planned
on using the dirty bitmap to be forced to treat the entire image
as dirty as a safety fallback. Furthermore, if the QMP client
successfully exports a disk but then fails to add the bitmap, it
has to take on the burden of removing the export. Since we don't
allow changing the exposed dirty bitmap (whether to a different
bitmap, or removing advertisement of the bitmap), it is nicer to
make the bitmap tied to the export at the time the export is
created, with automatic failure to export if the bitmap is not
available.
The experimental command included an optional 'bitmap-export-name'
field for remapping the name exposed over NBD to be different from
the bitmap name stored on disk. However, my libvirt demo code
for implementing differential backups on top of persistent bitmaps
did not need to take advantage of that feature (it is instead
possible to create a new temporary bitmap with the desired name,
use block-dirty-bitmap-merge to merge one or more persistent
bitmaps into the temporary, then associate the temporary with the
NBD export, if control is needed over the exported bitmap name).
Hence, I'm not copying that part of the experiment over to the
stable addition. For more details on the libvirt demo, see
https://www.redhat.com/archives/libvir-list/2018-October/msg01254.html,
https://kvmforum2018.sched.com/event/FzuB/facilitating-incremental-backup-eric-blake-red-hat
This patch focuses on the user interface, and reduces (but does
not completely eliminate) the window where an NBD client can see
the export but not the dirty bitmap, with less work to clean up
after errors. Later patches will add further cleanups now that
this interface is declared stable via a single QMP command,
including removing the race window.
Update test 223 to use the new interface.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20190111194720.15671-6-eblake@redhat.com>
Let management know if there were any problems communicating with
qemu-pr-helper. The event is edge-triggered, and is sent every time
the connection status of the pr-manager-helper object changes.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
For now, the actual command ix x-nbd-server-add-bitmap, reflecting
the fact that we are still working on libvirt code that proves the
command works as needed, and also the fact that we may remove
bitmap-export-name (and just require that the exported name be the
bitmap name).
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20180609151758.17343-6-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: make the command experimental by adding x- prefix]
Signed-off-by: Eric Blake <eblake@redhat.com>
Add command for removing an export. It is needed for cases when we
don't want to keep the export after the operation on it was completed.
The other example is a temporary node, created with blockdev-add.
If we want to delete it we should firstly remove any corresponding
NBD export.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20180119135719.24745-3-vsementsov@virtuozzo.com>
[eblake: drop dead nb_clients code]
Signed-off-by: Eric Blake <eblake@redhat.com>
Allow user to specify name for new export, to not reuse internal
node name and to not show it to clients.
This also allows creating several exports per device.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180119135719.24745-2-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
The generated QEMU QMP reference is now structured as follows:
1.1 Introduction
1.2 Stability Considerations
1.3 Common data types
1.4 Socket data types
1.5 VM run state
1.6 Cryptography
1.7 Block devices
1.7.1 Block core (VM unrelated)
1.7.2 QAPI block definitions (vm unrelated)
1.8 Character devices
1.9 Net devices
1.10 Rocker switch device
1.11 TPM (trusted platform module) devices
1.12 Remote desktop
1.12.1 Spice
1.12.2 VNC
1.13 Input
1.14 Migration
1.15 Transactions
1.16 Tracing
1.17 QMP introspection
1.18 Miscellanea
Section "1.18 Miscellanea" is still too big: it documents 134 symbols.
Section "1.7.1 Block core (VM unrelated)" is also rather big: 128
symbols. All the others are of reasonable size.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1503602048-12268-17-git-send-email-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
In the process of getting rid of docs/qmp-commands.txt, we managed
to regress on some of the text that changed after the point where
the move was first branched and when the move actually occurred.
For example, commit 3282eca for blockdev-snapshot re-added the
extra "options" layer which had been cleaned up in commit 0153d2f.
This clears up all regressions identified over the range
02b351d..bd6092e:
https://lists.gnu.org/archive/html/qemu-devel/2017-05/msg05127.html
as well as a cleanup to x-blockdev-remove-medium to prefer
'id' over 'device' (matching the cleanup for 'eject').
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
The next commit will rename SocketAddressFlat to SocketAddress, and
the commit after that will replace most uses of SocketAddressLegacy by
SocketAddress, replacing most of this commit's renames right back.
Note that checkpatch emits a few "line over 80 characters" warnings.
The long lines are all temporary; the SocketAddressLegacy replacement
will shorten them again.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1493192202-3184-5-git-send-email-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
We traditionally mark optional members #optional in the doc comment.
Before commit 3313b61, this was entirely manual.
Commit 3313b61 added some automation because its qapi2texi.py relied
on #optional to determine whether a member is optional. This is no
longer the case since the previous commit: the only thing qapi2texi.py
still does with #optional is stripping it out. We still reject bogus
qapi-schema.json and six places for qga/qapi-schema.json.
Thus, you can't actually rely on #optional to see whether something is
optional. Yet we still make people add it manually. That's just
busy-work.
Drop the code to check, fix up and strip out #optional, along with all
instances of #optional. To keep it out, add code to reject it, to be
dropped again once the dust settles.
No change to generated documentation.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1489582656-31133-18-git-send-email-armbru@redhat.com>
Add some more section titles to organize the documentation we're going
to generate.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20170113144135.5150-10-marcandre.lureau@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Commit 2d76e72 failed to add a versioning tag to 'id'.
I audited all qapi*.json files from v2.7.0 to the current
state of the tree, and didn't find any other additions where
we failed to use a version tag.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 20161206160345.22425-1-eblake@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The documentation parser we are going to add expects a section name to
end with ':', otherwise the comment is treated as free-form text body.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20161117155504.21843-9-marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
The event currently only contains the BlockBackend name. However, with
anonymous BlockBackends, this is always the empty string. Add the qdev
ID (or if none was given, the QOM path) so that the user can still see
which device caused the event.
Event generation has to be moved from bdrv_eject() to the BlockBackend
because the BDS doesn't know the attached device, but that's easy
because blk_eject() is the only user of it.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
In order to remove the need for BlockBackend names in the external API,
we want to allow qdev device names in all device related commands.
This converts eject to accept a qdev device name.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
There is no reason why an NBD server couldn't be started for any node,
even if it's not on the top level. This converts nbd-server-add to
accept a node-name.
Note that there is a semantic difference between using a BlockBackend
name and the node name of its root: In the former case, the NBD server
is closed on eject; in the latter case, the NBD server doesn't drop its
reference and keeps the image file open this way.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
