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 26 #ifndef BLOCKJOB_INT_H 27 #define BLOCKJOB_INT_H 28 29 #include "block/blockjob.h" 30 #include "block/block.h" 31 32 /** 33 * BlockJobDriver: 34 * 35 * A class type for block job driver. 36 */ 37 struct BlockJobDriver { 38 /** Derived BlockJob struct size */ 39 size_t instance_size; 40 41 /** String describing the operation, part of query-block-jobs QMP API */ 42 BlockJobType job_type; 43 44 /** Mandatory: Entrypoint for the Coroutine. */ 45 CoroutineEntry *start; 46 47 /** 48 * Optional callback for job types whose completion must be triggered 49 * manually. 50 */ 51 void (*complete)(BlockJob *job, Error **errp); 52 53 /** 54 * If the callback is not NULL, prepare will be invoked when all the jobs 55 * belonging to the same transaction complete; or upon this job's completion 56 * if it is not in a transaction. 57 * 58 * This callback will not be invoked if the job has already failed. 59 * If it fails, abort and then clean will be called. 60 */ 61 int (*prepare)(BlockJob *job); 62 63 /** 64 * If the callback is not NULL, it will be invoked when all the jobs 65 * belonging to the same transaction complete; or upon this job's 66 * completion if it is not in a transaction. Skipped if NULL. 67 * 68 * All jobs will complete with a call to either .commit() or .abort() but 69 * never both. 70 */ 71 void (*commit)(BlockJob *job); 72 73 /** 74 * If the callback is not NULL, it will be invoked when any job in the 75 * same transaction fails; or upon this job's failure (due to error or 76 * cancellation) if it is not in a transaction. Skipped if NULL. 77 * 78 * All jobs will complete with a call to either .commit() or .abort() but 79 * never both. 80 */ 81 void (*abort)(BlockJob *job); 82 83 /** 84 * If the callback is not NULL, it will be invoked after a call to either 85 * .commit() or .abort(). Regardless of which callback is invoked after 86 * completion, .clean() will always be called, even if the job does not 87 * belong to a transaction group. 88 */ 89 void (*clean)(BlockJob *job); 90 91 /** 92 * If the callback is not NULL, it will be invoked when the job transitions 93 * into the paused state. Paused jobs must not perform any asynchronous 94 * I/O or event loop activity. This callback is used to quiesce jobs. 95 */ 96 void coroutine_fn (*pause)(BlockJob *job); 97 98 /** 99 * If the callback is not NULL, it will be invoked when the job transitions 100 * out of the paused state. Any asynchronous I/O or event loop activity 101 * should be restarted from this callback. 102 */ 103 void coroutine_fn (*resume)(BlockJob *job); 104 105 /* 106 * If the callback is not NULL, it will be invoked before the job is 107 * resumed in a new AioContext. This is the place to move any resources 108 * besides job->blk to the new AioContext. 109 */ 110 void (*attached_aio_context)(BlockJob *job, AioContext *new_context); 111 112 /* 113 * If the callback is not NULL, it will be invoked when the job has to be 114 * synchronously cancelled or completed; it should drain BlockDriverStates 115 * as required to ensure progress. 116 */ 117 void (*drain)(BlockJob *job); 118 }; 119 120 /** 121 * block_job_create: 122 * @job_id: The id of the newly-created job, or %NULL to have one 123 * generated automatically. 124 * @driver: The class object for the newly-created job. 125 * @txn: The transaction this job belongs to, if any. %NULL otherwise. 126 * @bs: The block 127 * @perm, @shared_perm: Permissions to request for @bs 128 * @speed: The maximum speed, in bytes per second, or 0 for unlimited. 129 * @flags: Creation flags for the Block Job. 130 * See @BlockJobCreateFlags 131 * @cb: Completion function for the job. 132 * @opaque: Opaque pointer value passed to @cb. 133 * @errp: Error object. 134 * 135 * Create a new long-running block device job and return it. The job 136 * will call @cb asynchronously when the job completes. Note that 137 * @bs may have been closed at the time the @cb it is called. If 138 * this is the case, the job may be reported as either cancelled or 139 * completed. 140 * 141 * This function is not part of the public job interface; it should be 142 * called from a wrapper that is specific to the job type. 143 */ 144 void *block_job_create(const char *job_id, const BlockJobDriver *driver, 145 BlockJobTxn *txn, BlockDriverState *bs, uint64_t perm, 146 uint64_t shared_perm, int64_t speed, int flags, 147 BlockCompletionFunc *cb, void *opaque, Error **errp); 148 149 /** 150 * block_job_sleep_ns: 151 * @job: The job that calls the function. 152 * @ns: How many nanoseconds to stop for. 153 * 154 * Put the job to sleep (assuming that it wasn't canceled) for @ns 155 * %QEMU_CLOCK_REALTIME nanoseconds. Canceling the job will immediately 156 * interrupt the wait. 157 */ 158 void block_job_sleep_ns(BlockJob *job, int64_t ns); 159 160 /** 161 * block_job_yield: 162 * @job: The job that calls the function. 163 * 164 * Yield the block job coroutine. 165 */ 166 void block_job_yield(BlockJob *job); 167 168 /** 169 * block_job_ratelimit_get_delay: 170 * 171 * Calculate and return delay for the next request in ns. See the documentation 172 * of ratelimit_calculate_delay() for details. 173 */ 174 int64_t block_job_ratelimit_get_delay(BlockJob *job, uint64_t n); 175 176 /** 177 * block_job_early_fail: 178 * @bs: The block device. 179 * 180 * The block job could not be started, free it. 181 */ 182 void block_job_early_fail(BlockJob *job); 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_is_cancelled: 196 * @job: The job being queried. 197 * 198 * Returns whether the job is scheduled for cancellation. 199 */ 200 bool block_job_is_cancelled(BlockJob *job); 201 202 /** 203 * block_job_pause_point: 204 * @job: The job that is ready to pause. 205 * 206 * Pause now if block_job_pause() has been called. Block jobs that perform 207 * lots of I/O must call this between requests so that the job can be paused. 208 */ 209 void coroutine_fn block_job_pause_point(BlockJob *job); 210 211 /** 212 * block_job_enter: 213 * @job: The job to enter. 214 * 215 * Continue the specified job by entering the coroutine. 216 */ 217 void block_job_enter(BlockJob *job); 218 219 /** 220 * block_job_event_ready: 221 * @job: The job which is now ready to be completed. 222 * 223 * Send a BLOCK_JOB_READY event for the specified job. 224 */ 225 void block_job_event_ready(BlockJob *job); 226 227 /** 228 * block_job_error_action: 229 * @job: The job to signal an error for. 230 * @on_err: The error action setting. 231 * @is_read: Whether the operation was a read. 232 * @error: The error that was reported. 233 * 234 * Report an I/O error for a block job and possibly stop the VM. Return the 235 * action that was selected based on @on_err and @error. 236 */ 237 BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err, 238 int is_read, int error); 239 240 typedef void BlockJobDeferToMainLoopFn(BlockJob *job, void *opaque); 241 242 /** 243 * block_job_defer_to_main_loop: 244 * @job: The job 245 * @fn: The function to run in the main loop 246 * @opaque: The opaque value that is passed to @fn 247 * 248 * This function must be called by the main job coroutine just before it 249 * returns. @fn is executed in the main loop with the BlockDriverState 250 * AioContext acquired. Block jobs must call bdrv_unref(), bdrv_close(), and 251 * anything that uses bdrv_drain_all() in the main loop. 252 * 253 * The @job AioContext is held while @fn executes. 254 */ 255 void block_job_defer_to_main_loop(BlockJob *job, 256 BlockJobDeferToMainLoopFn *fn, 257 void *opaque); 258 259 #endif 260