include/block/blockjob.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 #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 #qemu_aio_wait 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 #qemu_aio_wait, such as a timer.
  91      */
  92     bool busy;
  93
  94     /** Status that is published by the query-block-jobs QMP API */
  95     BlockDeviceIoStatus iostatus;
  96
  97     /** Offset that is published by the query-block-jobs QMP API */
  98     int64_t offset;
  99
 100     /** Length that is published by the query-block-jobs QMP API */
 101     int64_t len;
 102
 103     /** Speed that was set with @block_job_set_speed.  */
 104     int64_t speed;
 105
 106     /** The completion function that will be called when the job completes.  */
 107     BlockDriverCompletionFunc *cb;
 108
 109     /** Block other operations when block job is running */
 110     Error *blocker;
 111
 112     /** The opaque value that is passed to the completion function.  */
 113     void *opaque;
 114 };
 115
 116 /**
 117  * block_job_create:
 118  * @job_type: The class object for the newly-created job.
 119  * @bs: The block
 120  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 121  * @cb: Completion function for the job.
 122  * @opaque: Opaque pointer value passed to @cb.
 123  * @errp: Error object.
 124  *
 125  * Create a new long-running block device job and return it.  The job
 126  * will call @cb asynchronously when the job completes.  Note that
 127  * @bs may have been closed at the time the @cb it is called.  If
 128  * this is the case, the job may be reported as either cancelled or
 129  * completed.
 130  *
 131  * This function is not part of the public job interface; it should be
 132  * called from a wrapper that is specific to the job type.
 133  */
 134 void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
 135                        int64_t speed, BlockDriverCompletionFunc *cb,
 136                        void *opaque, Error **errp);
 137
 138 /**
 139  * block_job_sleep_ns:
 140  * @job: The job that calls the function.
 141  * @clock: The clock to sleep on.
 142  * @ns: How many nanoseconds to stop for.
 143  *
 144  * Put the job to sleep (assuming that it wasn't canceled) for @ns
 145  * nanoseconds.  Canceling the job will interrupt the wait immediately.
 146  */
 147 void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns);
 148
 149 /**
 150  * block_job_completed:
 151  * @job: The job being completed.
 152  * @ret: The status code.
 153  *
 154  * Call the completion function that was registered at creation time, and
 155  * free @job.
 156  */
 157 void block_job_completed(BlockJob *job, int ret);
 158
 159 /**
 160  * block_job_set_speed:
 161  * @job: The job to set the speed for.
 162  * @speed: The new value
 163  * @errp: Error object.
 164  *
 165  * Set a rate-limiting parameter for the job; the actual meaning may
 166  * vary depending on the job type.
 167  */
 168 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp);
 169
 170 /**
 171  * block_job_cancel:
 172  * @job: The job to be canceled.
 173  *
 174  * Asynchronously cancel the specified job.
 175  */
 176 void block_job_cancel(BlockJob *job);
 177
 178 /**
 179  * block_job_complete:
 180  * @job: The job to be completed.
 181  * @errp: Error object.
 182  *
 183  * Asynchronously complete the specified job.
 184  */
 185 void block_job_complete(BlockJob *job, Error **errp);
 186
 187 /**
 188  * block_job_is_cancelled:
 189  * @job: The job being queried.
 190  *
 191  * Returns whether the job is scheduled for cancellation.
 192  */
 193 bool block_job_is_cancelled(BlockJob *job);
 194
 195 /**
 196  * block_job_query:
 197  * @job: The job to get information about.
 198  *
 199  * Return information about a job.
 200  */
 201 BlockJobInfo *block_job_query(BlockJob *job);
 202
 203 /**
 204  * block_job_pause:
 205  * @job: The job to be paused.
 206  *
 207  * Asynchronously pause the specified job.
 208  */
 209 void block_job_pause(BlockJob *job);
 210
 211 /**
 212  * block_job_resume:
 213  * @job: The job to be resumed.
 214  *
 215  * Resume the specified job.
 216  */
 217 void block_job_resume(BlockJob *job);
 218
 219 /**
 220  * block_job_event_cancelled:
 221  * @job: The job whose information is requested.
 222  *
 223  * Send a BLOCK_JOB_CANCELLED event for the specified job.
 224  */
 225 void block_job_event_cancelled(BlockJob *job);
 226
 227 /**
 228  * block_job_ready:
 229  * @job: The job which is now ready to complete.
 230  * @msg: Error message. Only present on failure.
 231  *
 232  * Send a BLOCK_JOB_COMPLETED event for the specified job.
 233  */
 234 void block_job_event_completed(BlockJob *job, const char *msg);
 235
 236 /**
 237  * block_job_ready:
 238  * @job: The job which is now ready to complete.
 239  *
 240  * Send a BLOCK_JOB_READY event for the specified job.
 241  */
 242 void block_job_event_ready(BlockJob *job);
 243
 244 /**
 245  * block_job_is_paused:
 246  * @job: The job being queried.
 247  *
 248  * Returns whether the job is currently paused, or will pause
 249  * as soon as it reaches a sleeping point.
 250  */
 251 bool block_job_is_paused(BlockJob *job);
 252
 253 /**
 254  * block_job_cancel_sync:
 255  * @job: The job to be canceled.
 256  *
 257  * Synchronously cancel the job.  The completion callback is called
 258  * before the function returns.  The job may actually complete
 259  * instead of canceling itself; the circumstances under which this
 260  * happens depend on the kind of job that is active.
 261  *
 262  * Returns the return value from the job if the job actually completed
 263  * during the call, or -ECANCELED if it was canceled.
 264  */
 265 int block_job_cancel_sync(BlockJob *job);
 266
 267 /**
 268  * block_job_iostatus_reset:
 269  * @job: The job whose I/O status should be reset.
 270  *
 271  * Reset I/O status on @job and on BlockDriverState objects it uses,
 272  * other than job->bs.
 273  */
 274 void block_job_iostatus_reset(BlockJob *job);
 275
 276 /**
 277  * block_job_error_action:
 278  * @job: The job to signal an error for.
 279  * @bs: The block device on which to set an I/O error.
 280  * @on_err: The error action setting.
 281  * @is_read: Whether the operation was a read.
 282  * @error: The error that was reported.
 283  *
 284  * Report an I/O error for a block job and possibly stop the VM.  Return the
 285  * action that was selected based on @on_err and @error.
 286  */
 287 BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,
 288                                         BlockdevOnError on_err,
 289                                         int is_read, int error);
 290 #endif