1 /* 2 * Declarations for long-running block device operations 3 * 4 * Copyright (c) 2011 IBM Corp. 5 * Copyright (c) 2012 Red Hat, Inc. 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a copy 8 * of this software and associated documentation files (the "Software"), to deal 9 * in the Software without restriction, including without limitation the rights 10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 11 * copies of the Software, and to permit persons to whom the Software is 12 * furnished to do so, subject to the following conditions: 13 * 14 * The above copyright notice and this permission notice shall be included in 15 * all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 23 * THE SOFTWARE. 24 */ 25 #ifndef BLOCKJOB_H 26 #define BLOCKJOB_H 1 27 28 #include "block/block.h" 29 30 /** 31 * BlockJobDriver: 32 * 33 * A class type for block job driver. 34 */ 35 typedef struct BlockJobDriver { 36 /** Derived BlockJob struct size */ 37 size_t instance_size; 38 39 /** String describing the operation, part of query-block-jobs QMP API */ 40 BlockJobType job_type; 41 42 /** Optional callback for job types that support setting a speed limit */ 43 void (*set_speed)(BlockJob *job, int64_t speed, Error **errp); 44 45 /** Optional callback for job types that need to forward I/O status reset */ 46 void (*iostatus_reset)(BlockJob *job); 47 48 /** 49 * Optional callback for job types whose completion must be triggered 50 * manually. 51 */ 52 void (*complete)(BlockJob *job, Error **errp); 53 54 /** 55 * If the callback is not NULL, it will be invoked when all the jobs 56 * belonging to the same transaction complete; or upon this job's 57 * completion if it is not in a transaction. Skipped if NULL. 58 * 59 * All jobs will complete with a call to either .commit() or .abort() but 60 * never both. 61 */ 62 void (*commit)(BlockJob *job); 63 64 /** 65 * If the callback is not NULL, it will be invoked when any job in the 66 * same transaction fails; or upon this job's failure (due to error or 67 * cancellation) if it is not in a transaction. Skipped if NULL. 68 * 69 * All jobs will complete with a call to either .commit() or .abort() but 70 * never both. 71 */ 72 void (*abort)(BlockJob *job); 73 } BlockJobDriver; 74 75 /** 76 * BlockJob: 77 * 78 * Long-running operation on a BlockDriverState. 79 */ 80 struct BlockJob { 81 /** The job type, including the job vtable. */ 82 const BlockJobDriver *driver; 83 84 /** The block device on which the job is operating. */ 85 BlockDriverState *bs; 86 87 /** 88 * The ID of the block job. Currently the BlockBackend name of the BDS 89 * owning the job at the time when the job is started. 90 * 91 * TODO Decouple block job IDs from BlockBackend names 92 */ 93 char *id; 94 95 /** 96 * The coroutine that executes the job. If not NULL, it is 97 * reentered when busy is false and the job is cancelled. 98 */ 99 Coroutine *co; 100 101 /** 102 * Set to true if the job should cancel itself. The flag must 103 * always be tested just before toggling the busy flag from false 104 * to true. After a job has been cancelled, it should only yield 105 * if #aio_poll will ("sooner or later") reenter the coroutine. 106 */ 107 bool cancelled; 108 109 /** 110 * Counter for pause request. If non-zero, the block job is either paused, 111 * or if busy == true will pause itself as soon as possible. 112 */ 113 int pause_count; 114 115 /** 116 * Set to true if the job is paused by user. Can be unpaused with the 117 * block-job-resume QMP command. 118 */ 119 bool user_paused; 120 121 /** 122 * Set to false by the job while it is in a quiescent state, where 123 * no I/O is pending and the job has yielded on any condition 124 * that is not detected by #aio_poll, such as a timer. 125 */ 126 bool busy; 127 128 /** 129 * Set to true when the job is ready to be completed. 130 */ 131 bool ready; 132 133 /** 134 * Set to true when the job has deferred work to the main loop. 135 */ 136 bool deferred_to_main_loop; 137 138 /** Status that is published by the query-block-jobs QMP API */ 139 BlockDeviceIoStatus iostatus; 140 141 /** Offset that is published by the query-block-jobs QMP API */ 142 int64_t offset; 143 144 /** Length that is published by the query-block-jobs QMP API */ 145 int64_t len; 146 147 /** Speed that was set with @block_job_set_speed. */ 148 int64_t speed; 149 150 /** The completion function that will be called when the job completes. */ 151 BlockCompletionFunc *cb; 152 153 /** Block other operations when block job is running */ 154 Error *blocker; 155 156 /** The opaque value that is passed to the completion function. */ 157 void *opaque; 158 159 /** Reference count of the block job */ 160 int refcnt; 161 162 /* True if this job has reported completion by calling block_job_completed. 163 */ 164 bool completed; 165 166 /* ret code passed to block_job_completed. 167 */ 168 int ret; 169 170 /** Non-NULL if this job is part of a transaction */ 171 BlockJobTxn *txn; 172 QLIST_ENTRY(BlockJob) txn_list; 173 }; 174 175 /** 176 * block_job_create: 177 * @job_type: The class object for the newly-created job. 178 * @bs: The block 179 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 180 * @cb: Completion function for the job. 181 * @opaque: Opaque pointer value passed to @cb. 182 * @errp: Error object. 183 * 184 * Create a new long-running block device job and return it. The job 185 * will call @cb asynchronously when the job completes. Note that 186 * @bs may have been closed at the time the @cb it is called. If 187 * this is the case, the job may be reported as either cancelled or 188 * completed. 189 * 190 * This function is not part of the public job interface; it should be 191 * called from a wrapper that is specific to the job type. 192 */ 193 void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs, 194 int64_t speed, BlockCompletionFunc *cb, 195 void *opaque, Error **errp); 196 197 /** 198 * block_job_sleep_ns: 199 * @job: The job that calls the function. 200 * @clock: The clock to sleep on. 201 * @ns: How many nanoseconds to stop for. 202 * 203 * Put the job to sleep (assuming that it wasn't canceled) for @ns 204 * nanoseconds. Canceling the job will interrupt the wait immediately. 205 */ 206 void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns); 207 208 /** 209 * block_job_yield: 210 * @job: The job that calls the function. 211 * 212 * Yield the block job coroutine. 213 */ 214 void block_job_yield(BlockJob *job); 215 216 /** 217 * block_job_ref: 218 * @bs: The block device. 219 * 220 * Grab a reference to the block job. Should be paired with block_job_unref. 221 */ 222 void block_job_ref(BlockJob *job); 223 224 /** 225 * block_job_unref: 226 * @bs: The block device. 227 * 228 * Release reference to the block job and release resources if it is the last 229 * reference. 230 */ 231 void block_job_unref(BlockJob *job); 232 233 /** 234 * block_job_completed: 235 * @job: The job being completed. 236 * @ret: The status code. 237 * 238 * Call the completion function that was registered at creation time, and 239 * free @job. 240 */ 241 void block_job_completed(BlockJob *job, int ret); 242 243 /** 244 * block_job_set_speed: 245 * @job: The job to set the speed for. 246 * @speed: The new value 247 * @errp: Error object. 248 * 249 * Set a rate-limiting parameter for the job; the actual meaning may 250 * vary depending on the job type. 251 */ 252 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp); 253 254 /** 255 * block_job_cancel: 256 * @job: The job to be canceled. 257 * 258 * Asynchronously cancel the specified job. 259 */ 260 void block_job_cancel(BlockJob *job); 261 262 /** 263 * block_job_complete: 264 * @job: The job to be completed. 265 * @errp: Error object. 266 * 267 * Asynchronously complete the specified job. 268 */ 269 void block_job_complete(BlockJob *job, Error **errp); 270 271 /** 272 * block_job_is_cancelled: 273 * @job: The job being queried. 274 * 275 * Returns whether the job is scheduled for cancellation. 276 */ 277 bool block_job_is_cancelled(BlockJob *job); 278 279 /** 280 * block_job_query: 281 * @job: The job to get information about. 282 * 283 * Return information about a job. 284 */ 285 BlockJobInfo *block_job_query(BlockJob *job); 286 287 /** 288 * block_job_pause: 289 * @job: The job to be paused. 290 * 291 * Asynchronously pause the specified job. 292 */ 293 void block_job_pause(BlockJob *job); 294 295 /** 296 * block_job_resume: 297 * @job: The job to be resumed. 298 * 299 * Resume the specified job. Must be paired with a preceding block_job_pause. 300 */ 301 void block_job_resume(BlockJob *job); 302 303 /** 304 * block_job_enter: 305 * @job: The job to enter. 306 * 307 * Continue the specified job by entering the coroutine. 308 */ 309 void block_job_enter(BlockJob *job); 310 311 /** 312 * block_job_event_cancelled: 313 * @job: The job whose information is requested. 314 * 315 * Send a BLOCK_JOB_CANCELLED event for the specified job. 316 */ 317 void block_job_event_cancelled(BlockJob *job); 318 319 /** 320 * block_job_ready: 321 * @job: The job which is now ready to complete. 322 * @msg: Error message. Only present on failure. 323 * 324 * Send a BLOCK_JOB_COMPLETED event for the specified job. 325 */ 326 void block_job_event_completed(BlockJob *job, const char *msg); 327 328 /** 329 * block_job_ready: 330 * @job: The job which is now ready to complete. 331 * 332 * Send a BLOCK_JOB_READY event for the specified job. 333 */ 334 void block_job_event_ready(BlockJob *job); 335 336 /** 337 * block_job_is_paused: 338 * @job: The job being queried. 339 * 340 * Returns whether the job is currently paused, or will pause 341 * as soon as it reaches a sleeping point. 342 */ 343 bool block_job_is_paused(BlockJob *job); 344 345 /** 346 * block_job_cancel_sync: 347 * @job: The job to be canceled. 348 * 349 * Synchronously cancel the job. The completion callback is called 350 * before the function returns. The job may actually complete 351 * instead of canceling itself; the circumstances under which this 352 * happens depend on the kind of job that is active. 353 * 354 * Returns the return value from the job if the job actually completed 355 * during the call, or -ECANCELED if it was canceled. 356 */ 357 int block_job_cancel_sync(BlockJob *job); 358 359 /** 360 * block_job_complete_sync: 361 * @job: The job to be completed. 362 * @errp: Error object which may be set by block_job_complete(); this is not 363 * necessarily set on every error, the job return value has to be 364 * checked as well. 365 * 366 * Synchronously complete the job. The completion callback is called before the 367 * function returns, unless it is NULL (which is permissible when using this 368 * function). 369 * 370 * Returns the return value from the job. 371 */ 372 int block_job_complete_sync(BlockJob *job, Error **errp); 373 374 /** 375 * block_job_iostatus_reset: 376 * @job: The job whose I/O status should be reset. 377 * 378 * Reset I/O status on @job and on BlockDriverState objects it uses, 379 * other than job->bs. 380 */ 381 void block_job_iostatus_reset(BlockJob *job); 382 383 /** 384 * block_job_error_action: 385 * @job: The job to signal an error for. 386 * @bs: The block device on which to set an I/O error. 387 * @on_err: The error action setting. 388 * @is_read: Whether the operation was a read. 389 * @error: The error that was reported. 390 * 391 * Report an I/O error for a block job and possibly stop the VM. Return the 392 * action that was selected based on @on_err and @error. 393 */ 394 BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs, 395 BlockdevOnError on_err, 396 int is_read, int error); 397 398 typedef void BlockJobDeferToMainLoopFn(BlockJob *job, void *opaque); 399 400 /** 401 * block_job_defer_to_main_loop: 402 * @job: The job 403 * @fn: The function to run in the main loop 404 * @opaque: The opaque value that is passed to @fn 405 * 406 * Execute a given function in the main loop with the BlockDriverState 407 * AioContext acquired. Block jobs must call bdrv_unref(), bdrv_close(), and 408 * anything that uses bdrv_drain_all() in the main loop. 409 * 410 * The @job AioContext is held while @fn executes. 411 */ 412 void block_job_defer_to_main_loop(BlockJob *job, 413 BlockJobDeferToMainLoopFn *fn, 414 void *opaque); 415 416 /** 417 * block_job_txn_new: 418 * 419 * Allocate and return a new block job transaction. Jobs can be added to the 420 * transaction using block_job_txn_add_job(). 421 * 422 * The transaction is automatically freed when the last job completes or is 423 * cancelled. 424 * 425 * All jobs in the transaction either complete successfully or fail/cancel as a 426 * group. Jobs wait for each other before completing. Cancelling one job 427 * cancels all jobs in the transaction. 428 */ 429 BlockJobTxn *block_job_txn_new(void); 430 431 /** 432 * block_job_txn_unref: 433 * 434 * Release a reference that was previously acquired with block_job_txn_add_job 435 * or block_job_txn_new. If it's the last reference to the object, it will be 436 * freed. 437 */ 438 void block_job_txn_unref(BlockJobTxn *txn); 439 440 /** 441 * block_job_txn_add_job: 442 * @txn: The transaction (may be NULL) 443 * @job: Job to add to the transaction 444 * 445 * Add @job to the transaction. The @job must not already be in a transaction. 446 * The caller must call either block_job_txn_unref() or block_job_completed() 447 * to release the reference that is automatically grabbed here. 448 */ 449 void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job); 450 451 #endif 452