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     /** Mandatory: Entrypoint for the Coroutine. */
  51     CoroutineEntry *start;
  52
  53     /**
  54      * Optional callback for job types whose completion must be triggered
  55      * manually.
  56      */
  57     void (*complete)(BlockJob *job, Error **errp);
  58
  59     /**
  60      * If the callback is not NULL, it will be invoked when all the jobs
  61      * belonging to the same transaction complete; or upon this job's
  62      * completion if it is not in a transaction. Skipped if NULL.
  63      *
  64      * All jobs will complete with a call to either .commit() or .abort() but
  65      * never both.
  66      */
  67     void (*commit)(BlockJob *job);
  68
  69     /**
  70      * If the callback is not NULL, it will be invoked when any job in the
  71      * same transaction fails; or upon this job's failure (due to error or
  72      * cancellation) if it is not in a transaction. Skipped if NULL.
  73      *
  74      * All jobs will complete with a call to either .commit() or .abort() but
  75      * never both.
  76      */
  77     void (*abort)(BlockJob *job);
  78
  79     /**
  80      * If the callback is not NULL, it will be invoked after a call to either
  81      * .commit() or .abort(). Regardless of which callback is invoked after
  82      * completion, .clean() will always be called, even if the job does not
  83      * belong to a transaction group.
  84      */
  85     void (*clean)(BlockJob *job);
  86
  87     /**
  88      * If the callback is not NULL, it will be invoked when the job transitions
  89      * into the paused state.  Paused jobs must not perform any asynchronous
  90      * I/O or event loop activity.  This callback is used to quiesce jobs.
  91      */
  92     void coroutine_fn (*pause)(BlockJob *job);
  93
  94     /**
  95      * If the callback is not NULL, it will be invoked when the job transitions
  96      * out of the paused state.  Any asynchronous I/O or event loop activity
  97      * should be restarted from this callback.
  98      */
  99     void coroutine_fn (*resume)(BlockJob *job);
 100
 101     /*
 102      * If the callback is not NULL, it will be invoked before the job is
 103      * resumed in a new AioContext.  This is the place to move any resources
 104      * besides job->blk to the new AioContext.
 105      */
 106     void (*attached_aio_context)(BlockJob *job, AioContext *new_context);
 107
 108     /*
 109      * If the callback is not NULL, it will be invoked when the job has to be
 110      * synchronously cancelled or completed; it should drain BlockDriverStates
 111      * as required to ensure progress.
 112      */
 113     void (*drain)(BlockJob *job);
 114 };
 115
 116 /**
 117  * block_job_create:
 118  * @job_id: The id of the newly-created job, or %NULL to have one
 119  * generated automatically.
 120  * @job_type: The class object for the newly-created job.
 121  * @bs: The block
 122  * @perm, @shared_perm: Permissions to request for @bs
 123  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 124  * @cb: Completion function for the job.
 125  * @opaque: Opaque pointer value passed to @cb.
 126  * @errp: Error object.
 127  *
 128  * Create a new long-running block device job and return it.  The job
 129  * will call @cb asynchronously when the job completes.  Note that
 130  * @bs may have been closed at the time the @cb it is called.  If
 131  * this is the case, the job may be reported as either cancelled or
 132  * completed.
 133  *
 134  * This function is not part of the public job interface; it should be
 135  * called from a wrapper that is specific to the job type.
 136  */
 137 void *block_job_create(const char *job_id, const BlockJobDriver *driver,
 138                        BlockDriverState *bs, uint64_t perm,
 139                        uint64_t shared_perm, int64_t speed, int flags,
 140                        BlockCompletionFunc *cb, void *opaque, Error **errp);
 141
 142 /**
 143  * block_job_sleep_ns:
 144  * @job: The job that calls the function.
 145  * @clock: The clock to sleep on.
 146  * @ns: How many nanoseconds to stop for.
 147  *
 148  * Put the job to sleep (assuming that it wasn't canceled) for @ns
 149  * nanoseconds.  Canceling the job will interrupt the wait immediately.
 150  */
 151 void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns);
 152
 153 /**
 154  * block_job_yield:
 155  * @job: The job that calls the function.
 156  *
 157  * Yield the block job coroutine.
 158  */
 159 void block_job_yield(BlockJob *job);
 160
 161 /**
 162  * block_job_ref:
 163  * @bs: The block device.
 164  *
 165  * Grab a reference to the block job. Should be paired with block_job_unref.
 166  */
 167 void block_job_ref(BlockJob *job);
 168
 169 /**
 170  * block_job_unref:
 171  * @bs: The block device.
 172  *
 173  * Release reference to the block job and release resources if it is the last
 174  * reference.
 175  */
 176 void block_job_unref(BlockJob *job);
 177
 178 /**
 179  * block_job_completed:
 180  * @job: The job being completed.
 181  * @ret: The status code.
 182  *
 183  * Call the completion function that was registered at creation time, and
 184  * free @job.
 185  */
 186 void block_job_completed(BlockJob *job, int ret);
 187
 188 /**
 189  * block_job_is_cancelled:
 190  * @job: The job being queried.
 191  *
 192  * Returns whether the job is scheduled for cancellation.
 193  */
 194 bool block_job_is_cancelled(BlockJob *job);
 195
 196 /**
 197  * block_job_pause_point:
 198  * @job: The job that is ready to pause.
 199  *
 200  * Pause now if block_job_pause() has been called.  Block jobs that perform
 201  * lots of I/O must call this between requests so that the job can be paused.
 202  */
 203 void coroutine_fn block_job_pause_point(BlockJob *job);
 204
 205 /**
 206  * block_job_enter:
 207  * @job: The job to enter.
 208  *
 209  * Continue the specified job by entering the coroutine.
 210  */
 211 void block_job_enter(BlockJob *job);
 212
 213 /**
 214  * block_job_event_ready:
 215  * @job: The job which is now ready to be completed.
 216  *
 217  * Send a BLOCK_JOB_READY event for the specified job.
 218  */
 219 void block_job_event_ready(BlockJob *job);
 220
 221 /**
 222  * block_job_error_action:
 223  * @job: The job to signal an error for.
 224  * @on_err: The error action setting.
 225  * @is_read: Whether the operation was a read.
 226  * @error: The error that was reported.
 227  *
 228  * Report an I/O error for a block job and possibly stop the VM.  Return the
 229  * action that was selected based on @on_err and @error.
 230  */
 231 BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
 232                                         int is_read, int error);
 233
 234 typedef void BlockJobDeferToMainLoopFn(BlockJob *job, void *opaque);
 235
 236 /**
 237  * block_job_defer_to_main_loop:
 238  * @job: The job
 239  * @fn: The function to run in the main loop
 240  * @opaque: The opaque value that is passed to @fn
 241  *
 242  * Execute a given function in the main loop with the BlockDriverState
 243  * AioContext acquired.  Block jobs must call bdrv_unref(), bdrv_close(), and
 244  * anything that uses bdrv_drain_all() in the main loop.
 245  *
 246  * The @job AioContext is held while @fn executes.
 247  */
 248 void block_job_defer_to_main_loop(BlockJob *job,
 249                                   BlockJobDeferToMainLoopFn *fn,
 250                                   void *opaque);
 251
 252 #endif