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