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 } BlockJobDriver; 54 55 /** 56 * BlockJob: 57 * 58 * Long-running operation on a BlockDriverState. 59 */ 60 struct BlockJob { 61 /** The job type, including the job vtable. */ 62 const BlockJobDriver *driver; 63 64 /** The block device on which the job is operating. */ 65 BlockDriverState *bs; 66 67 /** 68 * The ID of the block job. Currently the BlockBackend name of the BDS 69 * owning the job at the time when the job is started. 70 * 71 * TODO Decouple block job IDs from BlockBackend names 72 */ 73 char *id; 74 75 /** 76 * The coroutine that executes the job. If not NULL, it is 77 * reentered when busy is false and the job is cancelled. 78 */ 79 Coroutine *co; 80 81 /** 82 * Set to true if the job should cancel itself. The flag must 83 * always be tested just before toggling the busy flag from false 84 * to true. After a job has been cancelled, it should only yield 85 * if #aio_poll will ("sooner or later") reenter the coroutine. 86 */ 87 bool cancelled; 88 89 /** 90 * Counter for pause request. If non-zero, the block job is either paused, 91 * or if busy == true will pause itself as soon as possible. 92 */ 93 int pause_count; 94 95 /** 96 * Set to true if the job is paused by user. Can be unpaused with the 97 * block-job-resume QMP command. 98 */ 99 bool user_paused; 100 101 /** 102 * Set to false by the job while it is in a quiescent state, where 103 * no I/O is pending and the job has yielded on any condition 104 * that is not detected by #aio_poll, such as a timer. 105 */ 106 bool busy; 107 108 /** 109 * Set to true when the job is ready to be completed. 110 */ 111 bool ready; 112 113 /** Status that is published by the query-block-jobs QMP API */ 114 BlockDeviceIoStatus iostatus; 115 116 /** Offset that is published by the query-block-jobs QMP API */ 117 int64_t offset; 118 119 /** Length that is published by the query-block-jobs QMP API */ 120 int64_t len; 121 122 /** Speed that was set with @block_job_set_speed. */ 123 int64_t speed; 124 125 /** The completion function that will be called when the job completes. */ 126 BlockCompletionFunc *cb; 127 128 /** Block other operations when block job is running */ 129 Error *blocker; 130 131 /** The opaque value that is passed to the completion function. */ 132 void *opaque; 133 }; 134 135 /** 136 * block_job_create: 137 * @job_type: The class object for the newly-created job. 138 * @bs: The block 139 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 140 * @cb: Completion function for the job. 141 * @opaque: Opaque pointer value passed to @cb. 142 * @errp: Error object. 143 * 144 * Create a new long-running block device job and return it. The job 145 * will call @cb asynchronously when the job completes. Note that 146 * @bs may have been closed at the time the @cb it is called. If 147 * this is the case, the job may be reported as either cancelled or 148 * completed. 149 * 150 * This function is not part of the public job interface; it should be 151 * called from a wrapper that is specific to the job type. 152 */ 153 void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs, 154 int64_t speed, BlockCompletionFunc *cb, 155 void *opaque, Error **errp); 156 157 /** 158 * block_job_sleep_ns: 159 * @job: The job that calls the function. 160 * @clock: The clock to sleep on. 161 * @ns: How many nanoseconds to stop for. 162 * 163 * Put the job to sleep (assuming that it wasn't canceled) for @ns 164 * nanoseconds. Canceling the job will interrupt the wait immediately. 165 */ 166 void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns); 167 168 /** 169 * block_job_yield: 170 * @job: The job that calls the function. 171 * 172 * Yield the block job coroutine. 173 */ 174 void block_job_yield(BlockJob *job); 175 176 /** 177 * block_job_release: 178 * @bs: The block device. 179 * 180 * Release job resources when an error occurred or job completed. 181 */ 182 void block_job_release(BlockDriverState *bs); 183 184 /** 185 * block_job_completed: 186 * @job: The job being completed. 187 * @ret: The status code. 188 * 189 * Call the completion function that was registered at creation time, and 190 * free @job. 191 */ 192 void block_job_completed(BlockJob *job, int ret); 193 194 /** 195 * block_job_set_speed: 196 * @job: The job to set the speed for. 197 * @speed: The new value 198 * @errp: Error object. 199 * 200 * Set a rate-limiting parameter for the job; the actual meaning may 201 * vary depending on the job type. 202 */ 203 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp); 204 205 /** 206 * block_job_cancel: 207 * @job: The job to be canceled. 208 * 209 * Asynchronously cancel the specified job. 210 */ 211 void block_job_cancel(BlockJob *job); 212 213 /** 214 * block_job_complete: 215 * @job: The job to be completed. 216 * @errp: Error object. 217 * 218 * Asynchronously complete the specified job. 219 */ 220 void block_job_complete(BlockJob *job, Error **errp); 221 222 /** 223 * block_job_is_cancelled: 224 * @job: The job being queried. 225 * 226 * Returns whether the job is scheduled for cancellation. 227 */ 228 bool block_job_is_cancelled(BlockJob *job); 229 230 /** 231 * block_job_query: 232 * @job: The job to get information about. 233 * 234 * Return information about a job. 235 */ 236 BlockJobInfo *block_job_query(BlockJob *job); 237 238 /** 239 * block_job_pause: 240 * @job: The job to be paused. 241 * 242 * Asynchronously pause the specified job. 243 */ 244 void block_job_pause(BlockJob *job); 245 246 /** 247 * block_job_resume: 248 * @job: The job to be resumed. 249 * 250 * Resume the specified job. Must be paired with a preceding block_job_pause. 251 */ 252 void block_job_resume(BlockJob *job); 253 254 /** 255 * block_job_enter: 256 * @job: The job to enter. 257 * 258 * Continue the specified job by entering the coroutine. 259 */ 260 void block_job_enter(BlockJob *job); 261 262 /** 263 * block_job_event_cancelled: 264 * @job: The job whose information is requested. 265 * 266 * Send a BLOCK_JOB_CANCELLED event for the specified job. 267 */ 268 void block_job_event_cancelled(BlockJob *job); 269 270 /** 271 * block_job_ready: 272 * @job: The job which is now ready to complete. 273 * @msg: Error message. Only present on failure. 274 * 275 * Send a BLOCK_JOB_COMPLETED event for the specified job. 276 */ 277 void block_job_event_completed(BlockJob *job, const char *msg); 278 279 /** 280 * block_job_ready: 281 * @job: The job which is now ready to complete. 282 * 283 * Send a BLOCK_JOB_READY event for the specified job. 284 */ 285 void block_job_event_ready(BlockJob *job); 286 287 /** 288 * block_job_is_paused: 289 * @job: The job being queried. 290 * 291 * Returns whether the job is currently paused, or will pause 292 * as soon as it reaches a sleeping point. 293 */ 294 bool block_job_is_paused(BlockJob *job); 295 296 /** 297 * block_job_cancel_sync: 298 * @job: The job to be canceled. 299 * 300 * Synchronously cancel the job. The completion callback is called 301 * before the function returns. The job may actually complete 302 * instead of canceling itself; the circumstances under which this 303 * happens depend on the kind of job that is active. 304 * 305 * Returns the return value from the job if the job actually completed 306 * during the call, or -ECANCELED if it was canceled. 307 */ 308 int block_job_cancel_sync(BlockJob *job); 309 310 /** 311 * block_job_complete_sync: 312 * @job: The job to be completed. 313 * @errp: Error object which may be set by block_job_complete(); this is not 314 * necessarily set on every error, the job return value has to be 315 * checked as well. 316 * 317 * Synchronously complete the job. The completion callback is called before the 318 * function returns, unless it is NULL (which is permissible when using this 319 * function). 320 * 321 * Returns the return value from the job. 322 */ 323 int block_job_complete_sync(BlockJob *job, Error **errp); 324 325 /** 326 * block_job_iostatus_reset: 327 * @job: The job whose I/O status should be reset. 328 * 329 * Reset I/O status on @job and on BlockDriverState objects it uses, 330 * other than job->bs. 331 */ 332 void block_job_iostatus_reset(BlockJob *job); 333 334 /** 335 * block_job_error_action: 336 * @job: The job to signal an error for. 337 * @bs: The block device on which to set an I/O error. 338 * @on_err: The error action setting. 339 * @is_read: Whether the operation was a read. 340 * @error: The error that was reported. 341 * 342 * Report an I/O error for a block job and possibly stop the VM. Return the 343 * action that was selected based on @on_err and @error. 344 */ 345 BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs, 346 BlockdevOnError on_err, 347 int is_read, int error); 348 349 typedef void BlockJobDeferToMainLoopFn(BlockJob *job, void *opaque); 350 351 /** 352 * block_job_defer_to_main_loop: 353 * @job: The job 354 * @fn: The function to run in the main loop 355 * @opaque: The opaque value that is passed to @fn 356 * 357 * Execute a given function in the main loop with the BlockDriverState 358 * AioContext acquired. Block jobs must call bdrv_unref(), bdrv_close(), and 359 * anything that uses bdrv_drain_all() in the main loop. 360 * 361 * The @job AioContext is held while @fn executes. 362 */ 363 void block_job_defer_to_main_loop(BlockJob *job, 364 BlockJobDeferToMainLoopFn *fn, 365 void *opaque); 366 367 #endif 368