5 # == Block device exports
8 { 'include': 'sockets.json' }
9 { 'include': 'block-core.json' }
14 # Keep this type consistent with the nbd-server-start arguments. The only
15 # intended difference is using SocketAddress instead of SocketAddressLegacy.
17 # @addr: Address on which to listen.
18 # @tls-creds: ID of the TLS credentials object (since 2.6).
19 # @tls-authz: ID of the QAuthZ authorization object used to validate
20 # the client's x509 distinguished name. This object is
21 # is only resolved at time of use, so can be deleted and
22 # recreated on the fly while the NBD server is active.
23 # If missing, it will default to denying access (since 4.0).
24 # @max-connections: The maximum number of connections to allow at the same
25 # time, 0 for unlimited. Setting this to 1 also stops
26 # the server from advertising multiple client support
27 # (since 5.2; default: 0)
31 { 'struct': 'NbdServerOptions',
32 'data': { 'addr': 'SocketAddress',
35 '*max-connections': 'uint32' } }
40 # Start an NBD server listening on the given host and port. Block
41 # devices can then be exported using @nbd-server-add. The NBD
42 # server will present them as named exports; for example, another
43 # QEMU instance could refer to them as "nbd:HOST:PORT:exportname=NAME".
45 # Keep this type consistent with the NbdServerOptions type. The only intended
46 # difference is using SocketAddressLegacy instead of SocketAddress.
48 # @addr: Address on which to listen.
49 # @tls-creds: ID of the TLS credentials object (since 2.6).
50 # @tls-authz: ID of the QAuthZ authorization object used to validate
51 # the client's x509 distinguished name. This object is
52 # is only resolved at time of use, so can be deleted and
53 # recreated on the fly while the NBD server is active.
54 # If missing, it will default to denying access (since 4.0).
55 # @max-connections: The maximum number of connections to allow at the same
56 # time, 0 for unlimited. Setting this to 1 also stops
57 # the server from advertising multiple client support
58 # (since 5.2; default: 0).
60 # Returns: error if the server is already running.
64 { 'command': 'nbd-server-start',
65 'data': { 'addr': 'SocketAddressLegacy',
68 '*max-connections': 'uint32' },
69 'allow-preconfig': true }
72 # @BlockExportOptionsNbdBase:
74 # An NBD block export (common options shared between nbd-server-add and
75 # the NBD branch of block-export-add).
77 # @name: Export name. If unspecified, the @device parameter is used as the
78 # export name. (Since 2.12)
80 # @description: Free-form description of the export, up to 4096 bytes.
85 { 'struct': 'BlockExportOptionsNbdBase',
86 'data': { '*name': 'str', '*description': 'str' } }
89 # @BlockExportOptionsNbd:
91 # An NBD block export (distinct options used in the NBD branch of
94 # @bitmaps: Also export each of the named dirty bitmaps reachable from
95 # @device, so the NBD client can use NBD_OPT_SET_META_CONTEXT with
96 # the metadata context name "qemu:dirty-bitmap:BITMAP" to inspect
98 # Since 7.1 bitmap may be specified by node/name pair.
100 # @allocation-depth: Also export the allocation depth map for @device, so
101 # the NBD client can use NBD_OPT_SET_META_CONTEXT with
102 # the metadata context name "qemu:allocation-depth" to
103 # inspect allocation details. (since 5.2)
107 { 'struct': 'BlockExportOptionsNbd',
108 'base': 'BlockExportOptionsNbdBase',
109 'data': { '*bitmaps': ['BlockDirtyBitmapOrStr'],
110 '*allocation-depth': 'bool' } }
113 # @BlockExportOptionsVhostUserBlk:
115 # A vhost-user-blk block export.
117 # @addr: The vhost-user socket on which to listen. Both 'unix' and 'fd'
118 # SocketAddress types are supported. Passed fds must be UNIX domain
120 # @logical-block-size: Logical block size in bytes. Defaults to 512 bytes.
121 # @num-queues: Number of request virtqueues. Must be greater than 0. Defaults
126 { 'struct': 'BlockExportOptionsVhostUserBlk',
127 'data': { 'addr': 'SocketAddress',
128 '*logical-block-size': 'size',
129 '*num-queues': 'uint16'} }
132 # @FuseExportAllowOther:
134 # Possible allow_other modes for FUSE exports.
136 # @off: Do not pass allow_other as a mount option.
138 # @on: Pass allow_other as a mount option.
140 # @auto: Try mounting with allow_other first, and if that fails, retry
141 # without allow_other.
145 { 'enum': 'FuseExportAllowOther',
146 'data': ['off', 'on', 'auto'] }
149 # @BlockExportOptionsFuse:
151 # Options for exporting a block graph node on some (file) mountpoint
154 # @mountpoint: Path on which to export the block device via FUSE.
155 # This must point to an existing regular file.
157 # @growable: Whether writes beyond the EOF should grow the block node
158 # accordingly. (default: false)
160 # @allow-other: If this is off, only qemu's user is allowed access to
161 # this export. That cannot be changed even with chmod or
163 # Enabling this option will allow other users access to
164 # the export with the FUSE mount option "allow_other".
165 # Note that using allow_other as a non-root user requires
166 # user_allow_other to be enabled in the global fuse.conf
167 # configuration file.
168 # In auto mode (the default), the FUSE export driver will
169 # first attempt to mount the export with allow_other, and
170 # if that fails, try again without.
171 # (since 6.1; default: auto)
175 { 'struct': 'BlockExportOptionsFuse',
176 'data': { 'mountpoint': 'str',
178 '*allow-other': 'FuseExportAllowOther' },
179 'if': 'CONFIG_FUSE' }
182 # @BlockExportOptionsVduseBlk:
184 # A vduse-blk block export.
186 # @name: the name of VDUSE device (must be unique across the host).
187 # @num-queues: the number of virtqueues. Defaults to 1.
188 # @queue-size: the size of virtqueue. Defaults to 256.
189 # @logical-block-size: Logical block size in bytes. Range [512, PAGE_SIZE]
190 # and must be power of 2. Defaults to 512 bytes.
191 # @serial: the serial number of virtio block device. Defaults to empty string.
195 { 'struct': 'BlockExportOptionsVduseBlk',
196 'data': { 'name': 'str',
197 '*num-queues': 'uint16',
198 '*queue-size': 'uint16',
199 '*logical-block-size': 'size',
203 # @NbdServerAddOptions:
205 # An NBD block export, per legacy nbd-server-add command.
207 # @device: The device name or node name of the node to be exported
209 # @writable: Whether clients should be able to write to the device via the
210 # NBD connection (default false).
212 # @bitmap: Also export a single dirty bitmap reachable from @device, so the
213 # NBD client can use NBD_OPT_SET_META_CONTEXT with the metadata
214 # context name "qemu:dirty-bitmap:BITMAP" to inspect the bitmap
219 { 'struct': 'NbdServerAddOptions',
220 'base': 'BlockExportOptionsNbdBase',
221 'data': { 'device': 'str',
222 '*writable': 'bool', '*bitmap': 'str' } }
227 # Export a block node to QEMU's embedded NBD server.
229 # The export name will be used as the id for the resulting block export.
232 # @deprecated: This command is deprecated. Use @block-export-add instead.
234 # Returns: error if the server is not running, or export with the same name
239 { 'command': 'nbd-server-add',
240 'data': 'NbdServerAddOptions', 'boxed': true, 'features': ['deprecated'],
241 'allow-preconfig': true }
244 # @BlockExportRemoveMode:
246 # Mode for removing a block export.
248 # @safe: Remove export if there are no existing connections, fail otherwise.
250 # @hard: Drop all connections immediately and remove export.
252 # TODO: Potential additional modes to be added in the future:
254 # hide: Just hide export from new clients, leave existing connections as is.
255 # Remove export after all clients are disconnected.
257 # soft: Hide export from new clients, answer with ESHUTDOWN for all further
258 # requests from existing clients.
262 {'enum': 'BlockExportRemoveMode', 'data': ['safe', 'hard']}
265 # @nbd-server-remove:
267 # Remove NBD export by name.
269 # @name: Block export id.
271 # @mode: Mode of command operation. See @BlockExportRemoveMode description.
275 # @deprecated: This command is deprecated. Use @block-export-del instead.
279 # - the server is not running
280 # - export is not found
281 # - mode is 'safe' and there are existing connections
285 { 'command': 'nbd-server-remove',
286 'data': {'name': 'str', '*mode': 'BlockExportRemoveMode'},
287 'features': ['deprecated'],
288 'allow-preconfig': true }
293 # Stop QEMU's embedded NBD server, and unregister all devices previously
294 # added via @nbd-server-add.
298 { 'command': 'nbd-server-stop',
299 'allow-preconfig': true }
304 # An enumeration of block export types
307 # @vhost-user-blk: vhost-user-blk export (since 5.2)
308 # @fuse: FUSE export (since: 6.0)
309 # @vduse-blk: vduse-blk export (since 7.1)
313 { 'enum': 'BlockExportType',
315 { 'name': 'vhost-user-blk',
316 'if': 'CONFIG_VHOST_USER_BLK_SERVER' },
317 { 'name': 'fuse', 'if': 'CONFIG_FUSE' },
318 { 'name': 'vduse-blk', 'if': 'CONFIG_VDUSE_BLK_EXPORT' } ] }
321 # @BlockExportOptions:
323 # Describes a block export, i.e. how single node should be exported on an
324 # external interface.
326 # @id: A unique identifier for the block export (across all export types)
328 # @node-name: The node name of the block node to be exported (since: 5.2)
330 # @writable: True if clients should be able to write to the export
333 # @writethrough: If true, caches are flushed after every write request to the
334 # export before completion is signalled. (since: 5.2;
337 # @iothread: The name of the iothread object where the export will run. The
338 # default is to use the thread currently associated with the
339 # block node. (since: 5.2)
341 # @fixed-iothread: True prevents the block node from being moved to another
342 # thread while the export is active. If true and @iothread is
343 # given, export creation fails if the block node cannot be
344 # moved to the iothread. The default is false. (since: 5.2)
348 { 'union': 'BlockExportOptions',
349 'base': { 'type': 'BlockExportType',
351 '*fixed-iothread': 'bool',
355 '*writethrough': 'bool' },
356 'discriminator': 'type',
358 'nbd': 'BlockExportOptionsNbd',
359 'vhost-user-blk': { 'type': 'BlockExportOptionsVhostUserBlk',
360 'if': 'CONFIG_VHOST_USER_BLK_SERVER' },
361 'fuse': { 'type': 'BlockExportOptionsFuse',
362 'if': 'CONFIG_FUSE' },
363 'vduse-blk': { 'type': 'BlockExportOptionsVduseBlk',
364 'if': 'CONFIG_VDUSE_BLK_EXPORT' }
370 # Creates a new block export.
374 { 'command': 'block-export-add',
375 'data': 'BlockExportOptions', 'boxed': true,
376 'allow-preconfig': true }
381 # Request to remove a block export. This drops the user's reference to the
382 # export, but the export may still stay around after this command returns until
383 # the shutdown of the export has completed.
385 # @id: Block export id.
387 # @mode: Mode of command operation. See @BlockExportRemoveMode description.
390 # Returns: Error if the export is not found or @mode is 'safe' and the export
391 # is still in use (e.g. by existing client connections)
395 { 'command': 'block-export-del',
396 'data': { 'id': 'str', '*mode': 'BlockExportRemoveMode' },
397 'allow-preconfig': true }
400 # @BLOCK_EXPORT_DELETED:
402 # Emitted when a block export is removed and its id can be reused.
404 # @id: Block export id.
408 { 'event': 'BLOCK_EXPORT_DELETED',
409 'data': { 'id': 'str' } }
414 # Information about a single block export.
416 # @id: The unique identifier for the block export
418 # @type: The block export type
420 # @node-name: The node name of the block node that is exported
422 # @shutting-down: True if the export is shutting down (e.g. after a
423 # block-export-del command, but before the shutdown has
428 { 'struct': 'BlockExportInfo',
429 'data': { 'id': 'str',
430 'type': 'BlockExportType',
432 'shutting-down': 'bool' } }
435 # @query-block-exports:
437 # Returns: A list of BlockExportInfo describing all block exports
441 { 'command': 'query-block-exports', 'returns': ['BlockExportInfo'],
442 'allow-preconfig': true }