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