include/block/blockjob_int.h

   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     /** Generic JobDriver callbacks and settings */
  39     JobDriver job_driver;
  40
  41     /** Mandatory: Entrypoint for the Coroutine. */
  42     CoroutineEntry *start;
  43
  44     /**
  45      * Optional callback for job types whose completion must be triggered
  46      * manually.
  47      */
  48     void (*complete)(BlockJob *job, Error **errp);
  49
  50     /**
  51      * If the callback is not NULL, prepare will be invoked when all the jobs
  52      * belonging to the same transaction complete; or upon this job's completion
  53      * if it is not in a transaction.
  54      *
  55      * This callback will not be invoked if the job has already failed.
  56      * If it fails, abort and then clean will be called.
  57      */
  58     int (*prepare)(BlockJob *job);
  59
  60     /**
  61      * If the callback is not NULL, it will be invoked when all the jobs
  62      * belonging to the same transaction complete; or upon this job's
  63      * completion if it is not in a transaction. Skipped if NULL.
  64      *
  65      * All jobs will complete with a call to either .commit() or .abort() but
  66      * never both.
  67      */
  68     void (*commit)(BlockJob *job);
  69
  70     /**
  71      * If the callback is not NULL, it will be invoked when any job in the
  72      * same transaction fails; or upon this job's failure (due to error or
  73      * cancellation) if it is not in a transaction. Skipped if NULL.
  74      *
  75      * All jobs will complete with a call to either .commit() or .abort() but
  76      * never both.
  77      */
  78     void (*abort)(BlockJob *job);
  79
  80     /**
  81      * If the callback is not NULL, it will be invoked after a call to either
  82      * .commit() or .abort(). Regardless of which callback is invoked after
  83      * completion, .clean() will always be called, even if the job does not
  84      * belong to a transaction group.
  85      */
  86     void (*clean)(BlockJob *job);
  87
  88     /**
  89      * If the callback is not NULL, it will be invoked when the job transitions
  90      * into the paused state.  Paused jobs must not perform any asynchronous
  91      * I/O or event loop activity.  This callback is used to quiesce jobs.
  92      */
  93     void coroutine_fn (*pause)(BlockJob *job);
  94
  95     /**
  96      * If the callback is not NULL, it will be invoked when the job transitions
  97      * out of the paused state.  Any asynchronous I/O or event loop activity
  98      * should be restarted from this callback.
  99      */
 100     void coroutine_fn (*resume)(BlockJob *job);
 101
 102     /*
 103      * If the callback is not NULL, it will be invoked before the job is
 104      * resumed in a new AioContext.  This is the place to move any resources
 105      * besides job->blk to the new AioContext.
 106      */
 107     void (*attached_aio_context)(BlockJob *job, AioContext *new_context);
 108
 109     /*
 110      * If the callback is not NULL, it will be invoked when the job has to be
 111      * synchronously cancelled or completed; it should drain BlockDriverStates
 112      * as required to ensure progress.
 113      */
 114     void (*drain)(BlockJob *job);
 115 };
 116
 117 /**
 118  * block_job_create:
 119  * @job_id: The id of the newly-created job, or %NULL to have one
 120  * generated automatically.
 121  * @driver: The class object for the newly-created job.
 122  * @txn: The transaction this job belongs to, if any. %NULL otherwise.
 123  * @bs: The block
 124  * @perm, @shared_perm: Permissions to request for @bs
 125  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 126  * @flags: Creation flags for the Block Job.
 127  *         See @BlockJobCreateFlags
 128  * @cb: Completion function for the job.
 129  * @opaque: Opaque pointer value passed to @cb.
 130  * @errp: Error object.
 131  *
 132  * Create a new long-running block device job and return it.  The job
 133  * will call @cb asynchronously when the job completes.  Note that
 134  * @bs may have been closed at the time the @cb it is called.  If
 135  * this is the case, the job may be reported as either cancelled or
 136  * completed.
 137  *
 138  * This function is not part of the public job interface; it should be
 139  * called from a wrapper that is specific to the job type.
 140  */
 141 void *block_job_create(const char *job_id, const BlockJobDriver *driver,
 142                        BlockJobTxn *txn, BlockDriverState *bs, uint64_t perm,
 143                        uint64_t shared_perm, int64_t speed, int flags,
 144                        BlockCompletionFunc *cb, void *opaque, Error **errp);
 145
 146 /**
 147  * block_job_free:
 148  * Callback to be used for JobDriver.free in all block jobs. Frees block job
 149  * specific resources in @job.
 150  */
 151 void block_job_free(Job *job);
 152
 153 /**
 154  * block_job_sleep_ns:
 155  * @job: The job that calls the function.
 156  * @ns: How many nanoseconds to stop for.
 157  *
 158  * Put the job to sleep (assuming that it wasn't canceled) for @ns
 159  * %QEMU_CLOCK_REALTIME nanoseconds.  Canceling the job will immediately
 160  * interrupt the wait.
 161  */
 162 void block_job_sleep_ns(BlockJob *job, int64_t ns);
 163
 164 /**
 165  * block_job_yield:
 166  * @job: The job that calls the function.
 167  *
 168  * Yield the block job coroutine.
 169  */
 170 void block_job_yield(BlockJob *job);
 171
 172 /**
 173  * block_job_ratelimit_get_delay:
 174  *
 175  * Calculate and return delay for the next request in ns. See the documentation
 176  * of ratelimit_calculate_delay() for details.
 177  */
 178 int64_t block_job_ratelimit_get_delay(BlockJob *job, uint64_t n);
 179
 180 /**
 181  * block_job_early_fail:
 182  * @bs: The block device.
 183  *
 184  * The block job could not be started, free it.
 185  */
 186 void block_job_early_fail(BlockJob *job);
 187
 188 /**
 189  * block_job_completed:
 190  * @job: The job being completed.
 191  * @ret: The status code.
 192  *
 193  * Call the completion function that was registered at creation time, and
 194  * free @job.
 195  */
 196 void block_job_completed(BlockJob *job, int ret);
 197
 198 /**
 199  * block_job_pause_point:
 200  * @job: The job that is ready to pause.
 201  *
 202  * Pause now if block_job_pause() has been called.  Block jobs that perform
 203  * lots of I/O must call this between requests so that the job can be paused.
 204  */
 205 void coroutine_fn block_job_pause_point(BlockJob *job);
 206
 207 /**
 208  * block_job_enter:
 209  * @job: The job to enter.
 210  *
 211  * Continue the specified job by entering the coroutine.
 212  */
 213 void block_job_enter(BlockJob *job);
 214
 215 /**
 216  * block_job_event_ready:
 217  * @job: The job which is now ready to be completed.
 218  *
 219  * Send a BLOCK_JOB_READY event for the specified job.
 220  */
 221 void block_job_event_ready(BlockJob *job);
 222
 223 /**
 224  * block_job_error_action:
 225  * @job: The job to signal an error for.
 226  * @on_err: The error action setting.
 227  * @is_read: Whether the operation was a read.
 228  * @error: The error that was reported.
 229  *
 230  * Report an I/O error for a block job and possibly stop the VM.  Return the
 231  * action that was selected based on @on_err and @error.
 232  */
 233 BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
 234                                         int is_read, int error);
 235
 236 typedef void BlockJobDeferToMainLoopFn(BlockJob *job, void *opaque);
 237
 238 /**
 239  * block_job_defer_to_main_loop:
 240  * @job: The job
 241  * @fn: The function to run in the main loop
 242  * @opaque: The opaque value that is passed to @fn
 243  *
 244  * This function must be called by the main job coroutine just before it
 245  * returns.  @fn is executed in the main loop with the BlockDriverState
 246  * AioContext acquired.  Block jobs must call bdrv_unref(), bdrv_close(), and
 247  * anything that uses bdrv_drain_all() in the main loop.
 248  *
 249  * The @job AioContext is held while @fn executes.
 250  */
 251 void block_job_defer_to_main_loop(BlockJob *job,
 252                                   BlockJobDeferToMainLoopFn *fn,
 253                                   void *opaque);
 254
 255 #endif