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     /** Mandatory: Entrypoint for the Coroutine. */
  48     CoroutineEntry *start;
  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, prepare will be invoked when all the jobs
  58      * belonging to the same transaction complete; or upon this job's completion
  59      * if it is not in a transaction.
  60      *
  61      * This callback will not be invoked if the job has already failed.
  62      * If it fails, abort and then clean will be called.
  63      */
  64     int (*prepare)(BlockJob *job);
  65
  66     /**
  67      * If the callback is not NULL, it will be invoked when all the jobs
  68      * belonging to the same transaction complete; or upon this job's
  69      * completion 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 (*commit)(BlockJob *job);
  75
  76     /**
  77      * If the callback is not NULL, it will be invoked when any job in the
  78      * same transaction fails; or upon this job's failure (due to error or
  79      * cancellation) if it is not in a transaction. Skipped if NULL.
  80      *
  81      * All jobs will complete with a call to either .commit() or .abort() but
  82      * never both.
  83      */
  84     void (*abort)(BlockJob *job);
  85
  86     /**
  87      * If the callback is not NULL, it will be invoked after a call to either
  88      * .commit() or .abort(). Regardless of which callback is invoked after
  89      * completion, .clean() will always be called, even if the job does not
  90      * belong to a transaction group.
  91      */
  92     void (*clean)(BlockJob *job);
  93
  94     /**
  95      * If the callback is not NULL, it will be invoked when the job transitions
  96      * into the paused state.  Paused jobs must not perform any asynchronous
  97      * I/O or event loop activity.  This callback is used to quiesce jobs.
  98      */
  99     void coroutine_fn (*pause)(BlockJob *job);
 100
 101     /**
 102      * If the callback is not NULL, it will be invoked when the job transitions
 103      * out of the paused state.  Any asynchronous I/O or event loop activity
 104      * should be restarted from this callback.
 105      */
 106     void coroutine_fn (*resume)(BlockJob *job);
 107
 108     /*
 109      * If the callback is not NULL, it will be invoked before the job is
 110      * resumed in a new AioContext.  This is the place to move any resources
 111      * besides job->blk to the new AioContext.
 112      */
 113     void (*attached_aio_context)(BlockJob *job, AioContext *new_context);
 114
 115     /*
 116      * If the callback is not NULL, it will be invoked when the job has to be
 117      * synchronously cancelled or completed; it should drain BlockDriverStates
 118      * as required to ensure progress.
 119      */
 120     void (*drain)(BlockJob *job);
 121 };
 122
 123 /**
 124  * block_job_create:
 125  * @job_id: The id of the newly-created job, or %NULL to have one
 126  * generated automatically.
 127  * @driver: The class object for the newly-created job.
 128  * @txn: The transaction this job belongs to, if any. %NULL otherwise.
 129  * @bs: The block
 130  * @perm, @shared_perm: Permissions to request for @bs
 131  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 132  * @flags: Creation flags for the Block Job.
 133  *         See @BlockJobCreateFlags
 134  * @cb: Completion function for the job.
 135  * @opaque: Opaque pointer value passed to @cb.
 136  * @errp: Error object.
 137  *
 138  * Create a new long-running block device job and return it.  The job
 139  * will call @cb asynchronously when the job completes.  Note that
 140  * @bs may have been closed at the time the @cb it is called.  If
 141  * this is the case, the job may be reported as either cancelled or
 142  * completed.
 143  *
 144  * This function is not part of the public job interface; it should be
 145  * called from a wrapper that is specific to the job type.
 146  */
 147 void *block_job_create(const char *job_id, const BlockJobDriver *driver,
 148                        BlockJobTxn *txn, BlockDriverState *bs, uint64_t perm,
 149                        uint64_t shared_perm, int64_t speed, int flags,
 150                        BlockCompletionFunc *cb, void *opaque, Error **errp);
 151
 152 /**
 153  * block_job_sleep_ns:
 154  * @job: The job that calls the function.
 155  * @ns: How many nanoseconds to stop for.
 156  *
 157  * Put the job to sleep (assuming that it wasn't canceled) for @ns
 158  * %QEMU_CLOCK_REALTIME nanoseconds.  Canceling the job will immediately
 159  * interrupt the wait.
 160  */
 161 void block_job_sleep_ns(BlockJob *job, int64_t ns);
 162
 163 /**
 164  * block_job_yield:
 165  * @job: The job that calls the function.
 166  *
 167  * Yield the block job coroutine.
 168  */
 169 void block_job_yield(BlockJob *job);
 170
 171 /**
 172  * block_job_pause_all:
 173  *
 174  * Asynchronously pause all jobs.
 175  */
 176 void block_job_pause_all(void);
 177
 178 /**
 179  * block_job_resume_all:
 180  *
 181  * Resume all block jobs.  Must be paired with a preceding block_job_pause_all.
 182  */
 183 void block_job_resume_all(void);
 184
 185 /**
 186  * block_job_early_fail:
 187  * @bs: The block device.
 188  *
 189  * The block job could not be started, free it.
 190  */
 191 void block_job_early_fail(BlockJob *job);
 192
 193 /**
 194  * block_job_completed:
 195  * @job: The job being completed.
 196  * @ret: The status code.
 197  *
 198  * Call the completion function that was registered at creation time, and
 199  * free @job.
 200  */
 201 void block_job_completed(BlockJob *job, int ret);
 202
 203 /**
 204  * block_job_is_cancelled:
 205  * @job: The job being queried.
 206  *
 207  * Returns whether the job is scheduled for cancellation.
 208  */
 209 bool block_job_is_cancelled(BlockJob *job);
 210
 211 /**
 212  * block_job_pause_point:
 213  * @job: The job that is ready to pause.
 214  *
 215  * Pause now if block_job_pause() has been called.  Block jobs that perform
 216  * lots of I/O must call this between requests so that the job can be paused.
 217  */
 218 void coroutine_fn block_job_pause_point(BlockJob *job);
 219
 220 /**
 221  * block_job_enter:
 222  * @job: The job to enter.
 223  *
 224  * Continue the specified job by entering the coroutine.
 225  */
 226 void block_job_enter(BlockJob *job);
 227
 228 /**
 229  * block_job_event_ready:
 230  * @job: The job which is now ready to be completed.
 231  *
 232  * Send a BLOCK_JOB_READY event for the specified job.
 233  */
 234 void block_job_event_ready(BlockJob *job);
 235
 236 /**
 237  * block_job_error_action:
 238  * @job: The job to signal an error for.
 239  * @on_err: The error action setting.
 240  * @is_read: Whether the operation was a read.
 241  * @error: The error that was reported.
 242  *
 243  * Report an I/O error for a block job and possibly stop the VM.  Return the
 244  * action that was selected based on @on_err and @error.
 245  */
 246 BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
 247                                         int is_read, int error);
 248
 249 typedef void BlockJobDeferToMainLoopFn(BlockJob *job, void *opaque);
 250
 251 /**
 252  * block_job_defer_to_main_loop:
 253  * @job: The job
 254  * @fn: The function to run in the main loop
 255  * @opaque: The opaque value that is passed to @fn
 256  *
 257  * This function must be called by the main job coroutine just before it
 258  * returns.  @fn is executed in the main loop with the BlockDriverState
 259  * AioContext acquired.  Block jobs must call bdrv_unref(), bdrv_close(), and
 260  * anything that uses bdrv_drain_all() in the main loop.
 261  *
 262  * The @job AioContext is held while @fn executes.
 263  */
 264 void block_job_defer_to_main_loop(BlockJob *job,
 265                                   BlockJobDeferToMainLoopFn *fn,
 266                                   void *opaque);
 267
 268 #endif