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     /** String describing the operation, part of query-block-jobs QMP API */
  42     JobType 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