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.h"
  29
  30 /**
  31  * BlockJobType:
  32  *
  33  * A class type for block job objects.
  34  */
  35 typedef struct BlockJobType {
  36     /** Derived BlockJob struct size */
  37     size_t instance_size;
  38
  39     /** String describing the operation, part of query-block-jobs QMP API */
  40     const char *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 } BlockJobType;
  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 BlockJobType *job_type;
  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     /** The opaque value that is passed to the completion function.  */
 110     void *opaque;
 111 };
 112
 113 /**
 114  * block_job_create:
 115  * @job_type: The class object for the newly-created job.
 116  * @bs: The block
 117  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 118  * @cb: Completion function for the job.
 119  * @opaque: Opaque pointer value passed to @cb.
 120  * @errp: Error object.
 121  *
 122  * Create a new long-running block device job and return it.  The job
 123  * will call @cb asynchronously when the job completes.  Note that
 124  * @bs may have been closed at the time the @cb it is called.  If
 125  * this is the case, the job may be reported as either cancelled or
 126  * completed.
 127  *
 128  * This function is not part of the public job interface; it should be
 129  * called from a wrapper that is specific to the job type.
 130  */
 131 void *block_job_create(const BlockJobType *job_type, BlockDriverState *bs,
 132                        int64_t speed, BlockDriverCompletionFunc *cb,
 133                        void *opaque, Error **errp);
 134
 135 /**
 136  * block_job_sleep_ns:
 137  * @job: The job that calls the function.
 138  * @clock: The clock to sleep on.
 139  * @ns: How many nanoseconds to stop for.
 140  *
 141  * Put the job to sleep (assuming that it wasn't canceled) for @ns
 142  * nanoseconds.  Canceling the job will interrupt the wait immediately.
 143  */
 144 void block_job_sleep_ns(BlockJob *job, QEMUClock *clock, int64_t ns);
 145
 146 /**
 147  * block_job_completed:
 148  * @job: The job being completed.
 149  * @ret: The status code.
 150  *
 151  * Call the completion function that was registered at creation time, and
 152  * free @job.
 153  */
 154 void block_job_completed(BlockJob *job, int ret);
 155
 156 /**
 157  * block_job_set_speed:
 158  * @job: The job to set the speed for.
 159  * @speed: The new value
 160  * @errp: Error object.
 161  *
 162  * Set a rate-limiting parameter for the job; the actual meaning may
 163  * vary depending on the job type.
 164  */
 165 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp);
 166
 167 /**
 168  * block_job_cancel:
 169  * @job: The job to be canceled.
 170  *
 171  * Asynchronously cancel the specified job.
 172  */
 173 void block_job_cancel(BlockJob *job);
 174
 175 /**
 176  * block_job_complete:
 177  * @job: The job to be completed.
 178  * @errp: Error object.
 179  *
 180  * Asynchronously complete the specified job.
 181  */
 182 void block_job_complete(BlockJob *job, Error **errp);
 183
 184 /**
 185  * block_job_is_cancelled:
 186  * @job: The job being queried.
 187  *
 188  * Returns whether the job is scheduled for cancellation.
 189  */
 190 bool block_job_is_cancelled(BlockJob *job);
 191
 192 /**
 193  * block_job_query:
 194  * @job: The job to get information about.
 195  *
 196  * Return information about a job.
 197  */
 198 BlockJobInfo *block_job_query(BlockJob *job);
 199
 200 /**
 201  * block_job_pause:
 202  * @job: The job to be paused.
 203  *
 204  * Asynchronously pause the specified job.
 205  */
 206 void block_job_pause(BlockJob *job);
 207
 208 /**
 209  * block_job_resume:
 210  * @job: The job to be resumed.
 211  *
 212  * Resume the specified job.
 213  */
 214 void block_job_resume(BlockJob *job);
 215
 216 /**
 217  * qobject_from_block_job:
 218  * @job: The job whose information is requested.
 219  *
 220  * Return a QDict corresponding to @job's query-block-jobs entry.
 221  */
 222 QObject *qobject_from_block_job(BlockJob *job);
 223
 224 /**
 225  * block_job_ready:
 226  * @job: The job which is now ready to complete.
 227  *
 228  * Send a BLOCK_JOB_READY event for the specified job.
 229  */
 230 void block_job_ready(BlockJob *job);
 231
 232 /**
 233  * block_job_is_paused:
 234  * @job: The job being queried.
 235  *
 236  * Returns whether the job is currently paused, or will pause
 237  * as soon as it reaches a sleeping point.
 238  */
 239 bool block_job_is_paused(BlockJob *job);
 240
 241 /**
 242  * block_job_cancel_sync:
 243  * @job: The job to be canceled.
 244  *
 245  * Synchronously cancel the job.  The completion callback is called
 246  * before the function returns.  The job may actually complete
 247  * instead of canceling itself; the circumstances under which this
 248  * happens depend on the kind of job that is active.
 249  *
 250  * Returns the return value from the job if the job actually completed
 251  * during the call, or -ECANCELED if it was canceled.
 252  */
 253 int block_job_cancel_sync(BlockJob *job);
 254
 255 /**
 256  * block_job_iostatus_reset:
 257  * @job: The job whose I/O status should be reset.
 258  *
 259  * Reset I/O status on @job and on BlockDriverState objects it uses,
 260  * other than job->bs.
 261  */
 262 void block_job_iostatus_reset(BlockJob *job);
 263
 264 /**
 265  * block_job_error_action:
 266  * @job: The job to signal an error for.
 267  * @bs: The block device on which to set an I/O error.
 268  * @on_err: The error action setting.
 269  * @is_read: Whether the operation was a read.
 270  * @error: The error that was reported.
 271  *
 272  * Report an I/O error for a block job and possibly stop the VM.  Return the
 273  * action that was selected based on @on_err and @error.
 274  */
 275 BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,
 276                                         BlockdevOnError on_err,
 277                                         int is_read, int error);
 278 #endif