2 * Declarations for long-running block device operations
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29 #include "block/block.h"
34 * A class type for block job driver.
36 typedef struct BlockJobDriver
{
37 /** Derived BlockJob struct size */
40 /** String describing the operation, part of query-block-jobs QMP API */
41 BlockJobType job_type
;
43 /** Optional callback for job types that support setting a speed limit */
44 void (*set_speed
)(BlockJob
*job
, int64_t speed
, Error
**errp
);
46 /** Optional callback for job types that need to forward I/O status reset */
47 void (*iostatus_reset
)(BlockJob
*job
);
50 * Optional callback for job types whose completion must be triggered
53 void (*complete
)(BlockJob
*job
, Error
**errp
);
56 * If the callback is not NULL, it will be invoked when all the jobs
57 * belonging to the same transaction complete; or upon this job's
58 * completion if it is not in a transaction. Skipped if NULL.
60 * All jobs will complete with a call to either .commit() or .abort() but
63 void (*commit
)(BlockJob
*job
);
66 * If the callback is not NULL, it will be invoked when any job in the
67 * same transaction fails; or upon this job's failure (due to error or
68 * cancellation) if it is not in a transaction. Skipped if NULL.
70 * All jobs will complete with a call to either .commit() or .abort() but
73 void (*abort
)(BlockJob
*job
);
76 * If the callback is not NULL, it will be invoked when the job transitions
77 * into the paused state. Paused jobs must not perform any asynchronous
78 * I/O or event loop activity. This callback is used to quiesce jobs.
80 void coroutine_fn (*pause
)(BlockJob
*job
);
83 * If the callback is not NULL, it will be invoked when the job transitions
84 * out of the paused state. Any asynchronous I/O or event loop activity
85 * should be restarted from this callback.
87 void coroutine_fn (*resume
)(BlockJob
*job
);
90 * If the callback is not NULL, it will be invoked before the job is
91 * resumed in a new AioContext. This is the place to move any resources
92 * besides job->blk to the new AioContext.
94 void (*attached_aio_context
)(BlockJob
*job
, AioContext
*new_context
);
97 * If the callback is not NULL, it will be invoked when the job has to be
98 * synchronously cancelled or completed; it should drain BlockDriverStates
99 * as required to ensure progress.
101 void (*drain
)(BlockJob
*job
);
107 * Long-running operation on a BlockDriverState.
110 /** The job type, including the job vtable. */
111 const BlockJobDriver
*driver
;
113 /** The block device on which the job is operating. */
117 * The ID of the block job.
122 * The coroutine that executes the job. If not NULL, it is
123 * reentered when busy is false and the job is cancelled.
128 * Set to true if the job should cancel itself. The flag must
129 * always be tested just before toggling the busy flag from false
130 * to true. After a job has been cancelled, it should only yield
131 * if #aio_poll will ("sooner or later") reenter the coroutine.
136 * Counter for pause request. If non-zero, the block job is either paused,
137 * or if busy == true will pause itself as soon as possible.
142 * Set to true if the job is paused by user. Can be unpaused with the
143 * block-job-resume QMP command.
148 * Set to false by the job while the coroutine has yielded and may be
149 * re-entered by block_job_enter(). There may still be I/O or event loop
155 * Set to true by the job while it is in a quiescent state, where
156 * no I/O or event loop activity is pending.
161 * Set to true when the job is ready to be completed.
166 * Set to true when the job has deferred work to the main loop.
168 bool deferred_to_main_loop
;
170 /** Element of the list of block jobs */
171 QLIST_ENTRY(BlockJob
) job_list
;
173 /** Status that is published by the query-block-jobs QMP API */
174 BlockDeviceIoStatus iostatus
;
176 /** Offset that is published by the query-block-jobs QMP API */
179 /** Length that is published by the query-block-jobs QMP API */
182 /** Speed that was set with @block_job_set_speed. */
185 /** The completion function that will be called when the job completes. */
186 BlockCompletionFunc
*cb
;
188 /** Block other operations when block job is running */
191 /** The opaque value that is passed to the completion function. */
194 /** Reference count of the block job */
197 /* True if this job has reported completion by calling block_job_completed.
201 /* ret code passed to block_job_completed.
205 /** Non-NULL if this job is part of a transaction */
207 QLIST_ENTRY(BlockJob
) txn_list
;
212 * @job: A block job, or %NULL.
214 * Get the next element from the list of block jobs after @job, or the
215 * first one if @job is %NULL.
217 * Returns the requested job, or %NULL if there are no more jobs left.
219 BlockJob
*block_job_next(BlockJob
*job
);
223 * @id: The id of the block job.
225 * Get the block job identified by @id (which must not be %NULL).
227 * Returns the requested job, or %NULL if it doesn't exist.
229 BlockJob
*block_job_get(const char *id
);
233 * @job_id: The id of the newly-created job, or %NULL to have one
234 * generated automatically.
235 * @job_type: The class object for the newly-created job.
237 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
238 * @cb: Completion function for the job.
239 * @opaque: Opaque pointer value passed to @cb.
240 * @errp: Error object.
242 * Create a new long-running block device job and return it. The job
243 * will call @cb asynchronously when the job completes. Note that
244 * @bs may have been closed at the time the @cb it is called. If
245 * this is the case, the job may be reported as either cancelled or
248 * This function is not part of the public job interface; it should be
249 * called from a wrapper that is specific to the job type.
251 void *block_job_create(const char *job_id
, const BlockJobDriver
*driver
,
252 BlockDriverState
*bs
, int64_t speed
,
253 BlockCompletionFunc
*cb
, void *opaque
, Error
**errp
);
256 * block_job_sleep_ns:
257 * @job: The job that calls the function.
258 * @clock: The clock to sleep on.
259 * @ns: How many nanoseconds to stop for.
261 * Put the job to sleep (assuming that it wasn't canceled) for @ns
262 * nanoseconds. Canceling the job will interrupt the wait immediately.
264 void block_job_sleep_ns(BlockJob
*job
, QEMUClockType type
, int64_t ns
);
268 * @job: The job that calls the function.
270 * Yield the block job coroutine.
272 void block_job_yield(BlockJob
*job
);
276 * @bs: The block device.
278 * Grab a reference to the block job. Should be paired with block_job_unref.
280 void block_job_ref(BlockJob
*job
);
284 * @bs: The block device.
286 * Release reference to the block job and release resources if it is the last
289 void block_job_unref(BlockJob
*job
);
292 * block_job_completed:
293 * @job: The job being completed.
294 * @ret: The status code.
296 * Call the completion function that was registered at creation time, and
299 void block_job_completed(BlockJob
*job
, int ret
);
302 * block_job_set_speed:
303 * @job: The job to set the speed for.
304 * @speed: The new value
305 * @errp: Error object.
307 * Set a rate-limiting parameter for the job; the actual meaning may
308 * vary depending on the job type.
310 void block_job_set_speed(BlockJob
*job
, int64_t speed
, Error
**errp
);
314 * @job: The job to be canceled.
316 * Asynchronously cancel the specified job.
318 void block_job_cancel(BlockJob
*job
);
321 * block_job_complete:
322 * @job: The job to be completed.
323 * @errp: Error object.
325 * Asynchronously complete the specified job.
327 void block_job_complete(BlockJob
*job
, Error
**errp
);
330 * block_job_is_cancelled:
331 * @job: The job being queried.
333 * Returns whether the job is scheduled for cancellation.
335 bool block_job_is_cancelled(BlockJob
*job
);
339 * @job: The job to get information about.
341 * Return information about a job.
343 BlockJobInfo
*block_job_query(BlockJob
*job
);
346 * block_job_pause_point:
347 * @job: The job that is ready to pause.
349 * Pause now if block_job_pause() has been called. Block jobs that perform
350 * lots of I/O must call this between requests so that the job can be paused.
352 void coroutine_fn
block_job_pause_point(BlockJob
*job
);
356 * @job: The job to be paused.
358 * Asynchronously pause the specified job.
360 void block_job_pause(BlockJob
*job
);
364 * @job: The job to be resumed.
366 * Resume the specified job. Must be paired with a preceding block_job_pause.
368 void block_job_resume(BlockJob
*job
);
372 * @job: The job to enter.
374 * Continue the specified job by entering the coroutine.
376 void block_job_enter(BlockJob
*job
);
379 * block_job_event_cancelled:
380 * @job: The job whose information is requested.
382 * Send a BLOCK_JOB_CANCELLED event for the specified job.
384 void block_job_event_cancelled(BlockJob
*job
);
388 * @job: The job which is now ready to complete.
389 * @msg: Error message. Only present on failure.
391 * Send a BLOCK_JOB_COMPLETED event for the specified job.
393 void block_job_event_completed(BlockJob
*job
, const char *msg
);
397 * @job: The job which is now ready to complete.
399 * Send a BLOCK_JOB_READY event for the specified job.
401 void block_job_event_ready(BlockJob
*job
);
404 * block_job_cancel_sync:
405 * @job: The job to be canceled.
407 * Synchronously cancel the job. The completion callback is called
408 * before the function returns. The job may actually complete
409 * instead of canceling itself; the circumstances under which this
410 * happens depend on the kind of job that is active.
412 * Returns the return value from the job if the job actually completed
413 * during the call, or -ECANCELED if it was canceled.
415 int block_job_cancel_sync(BlockJob
*job
);
418 * block_job_cancel_sync_all:
420 * Synchronously cancels all jobs using block_job_cancel_sync().
422 void block_job_cancel_sync_all(void);
425 * block_job_complete_sync:
426 * @job: The job to be completed.
427 * @errp: Error object which may be set by block_job_complete(); this is not
428 * necessarily set on every error, the job return value has to be
431 * Synchronously complete the job. The completion callback is called before the
432 * function returns, unless it is NULL (which is permissible when using this
435 * Returns the return value from the job.
437 int block_job_complete_sync(BlockJob
*job
, Error
**errp
);
440 * block_job_iostatus_reset:
441 * @job: The job whose I/O status should be reset.
443 * Reset I/O status on @job and on BlockDriverState objects it uses,
444 * other than job->blk.
446 void block_job_iostatus_reset(BlockJob
*job
);
449 * block_job_error_action:
450 * @job: The job to signal an error for.
451 * @on_err: The error action setting.
452 * @is_read: Whether the operation was a read.
453 * @error: The error that was reported.
455 * Report an I/O error for a block job and possibly stop the VM. Return the
456 * action that was selected based on @on_err and @error.
458 BlockErrorAction
block_job_error_action(BlockJob
*job
, BlockdevOnError on_err
,
459 int is_read
, int error
);
461 typedef void BlockJobDeferToMainLoopFn(BlockJob
*job
, void *opaque
);
464 * block_job_defer_to_main_loop:
466 * @fn: The function to run in the main loop
467 * @opaque: The opaque value that is passed to @fn
469 * Execute a given function in the main loop with the BlockDriverState
470 * AioContext acquired. Block jobs must call bdrv_unref(), bdrv_close(), and
471 * anything that uses bdrv_drain_all() in the main loop.
473 * The @job AioContext is held while @fn executes.
475 void block_job_defer_to_main_loop(BlockJob
*job
,
476 BlockJobDeferToMainLoopFn
*fn
,
482 * Allocate and return a new block job transaction. Jobs can be added to the
483 * transaction using block_job_txn_add_job().
485 * The transaction is automatically freed when the last job completes or is
488 * All jobs in the transaction either complete successfully or fail/cancel as a
489 * group. Jobs wait for each other before completing. Cancelling one job
490 * cancels all jobs in the transaction.
492 BlockJobTxn
*block_job_txn_new(void);
495 * block_job_txn_unref:
497 * Release a reference that was previously acquired with block_job_txn_add_job
498 * or block_job_txn_new. If it's the last reference to the object, it will be
501 void block_job_txn_unref(BlockJobTxn
*txn
);
504 * block_job_txn_add_job:
505 * @txn: The transaction (may be NULL)
506 * @job: Job to add to the transaction
508 * Add @job to the transaction. The @job must not already be in a transaction.
509 * The caller must call either block_job_txn_unref() or block_job_completed()
510 * to release the reference that is automatically grabbed here.
512 void block_job_txn_add_job(BlockJobTxn
*txn
, BlockJob
*job
);