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     /** Generic JobDriver callbacks and settings */
  39     JobDriver job_driver;
  40
  41     /**
  42      * Optional callback for job types whose completion must be triggered
  43      * manually.
  44      */
  45     void (*complete)(BlockJob *job, Error **errp);
  46
  47     /**
  48      * If the callback is not NULL, prepare will be invoked when all the jobs
  49      * belonging to the same transaction complete; or upon this job's completion
  50      * if it is not in a transaction.
  51      *
  52      * This callback will not be invoked if the job has already failed.
  53      * If it fails, abort and then clean will be called.
  54      */
  55     int (*prepare)(BlockJob *job);
  56
  57     /**
  58      * If the callback is not NULL, it will be invoked when all the jobs
  59      * belonging to the same transaction complete; or upon this job's
  60      * completion if it is not in a transaction. Skipped if NULL.
  61      *
  62      * All jobs will complete with a call to either .commit() or .abort() but
  63      * never both.
  64      */
  65     void (*commit)(BlockJob *job);
  66
  67     /**
  68      * If the callback is not NULL, it will be invoked when any job in the
  69      * same transaction fails; or upon this job's failure (due to error or
  70      * cancellation) if it is not in a transaction. Skipped if NULL.
  71      *
  72      * All jobs will complete with a call to either .commit() or .abort() but
  73      * never both.
  74      */
  75     void (*abort)(BlockJob *job);
  76
  77     /**
  78      * If the callback is not NULL, it will be invoked after a call to either
  79      * .commit() or .abort(). Regardless of which callback is invoked after
  80      * completion, .clean() will always be called, even if the job does not
  81      * belong to a transaction group.
  82      */
  83     void (*clean)(BlockJob *job);
  84
  85     /*
  86      * If the callback is not NULL, it will be invoked before the job is
  87      * resumed in a new AioContext.  This is the place to move any resources
  88      * besides job->blk to the new AioContext.
  89      */
  90     void (*attached_aio_context)(BlockJob *job, AioContext *new_context);
  91
  92     /*
  93      * If the callback is not NULL, it will be invoked when the job has to be
  94      * synchronously cancelled or completed; it should drain BlockDriverStates
  95      * as required to ensure progress.
  96      */
  97     void (*drain)(BlockJob *job);
  98 };
  99
 100 /**
 101  * block_job_create:
 102  * @job_id: The id of the newly-created job, or %NULL to have one
 103  * generated automatically.
 104  * @driver: The class object for the newly-created job.
 105  * @txn: The transaction this job belongs to, if any. %NULL otherwise.
 106  * @bs: The block
 107  * @perm, @shared_perm: Permissions to request for @bs
 108  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 109  * @flags: Creation flags for the Block Job.
 110  *         See @BlockJobCreateFlags
 111  * @cb: Completion function for the job.
 112  * @opaque: Opaque pointer value passed to @cb.
 113  * @errp: Error object.
 114  *
 115  * Create a new long-running block device job and return it.  The job
 116  * will call @cb asynchronously when the job completes.  Note that
 117  * @bs may have been closed at the time the @cb it is called.  If
 118  * this is the case, the job may be reported as either cancelled or
 119  * completed.
 120  *
 121  * This function is not part of the public job interface; it should be
 122  * called from a wrapper that is specific to the job type.
 123  */
 124 void *block_job_create(const char *job_id, const BlockJobDriver *driver,
 125                        BlockJobTxn *txn, BlockDriverState *bs, uint64_t perm,
 126                        uint64_t shared_perm, int64_t speed, int flags,
 127                        BlockCompletionFunc *cb, void *opaque, Error **errp);
 128
 129 /**
 130  * block_job_free:
 131  * Callback to be used for JobDriver.free in all block jobs. Frees block job
 132  * specific resources in @job.
 133  */
 134 void block_job_free(Job *job);
 135
 136 /**
 137  * block_job_yield:
 138  * @job: The job that calls the function.
 139  *
 140  * Yield the block job coroutine.
 141  */
 142 void block_job_yield(BlockJob *job);
 143
 144 /**
 145  * block_job_ratelimit_get_delay:
 146  *
 147  * Calculate and return delay for the next request in ns. See the documentation
 148  * of ratelimit_calculate_delay() for details.
 149  */
 150 int64_t block_job_ratelimit_get_delay(BlockJob *job, uint64_t n);
 151
 152 /**
 153  * block_job_early_fail:
 154  * @bs: The block device.
 155  *
 156  * The block job could not be started, free it.
 157  */
 158 void block_job_early_fail(BlockJob *job);
 159
 160 /**
 161  * block_job_completed:
 162  * @job: The job being completed.
 163  * @ret: The status code.
 164  *
 165  * Call the completion function that was registered at creation time, and
 166  * free @job.
 167  */
 168 void block_job_completed(BlockJob *job, int ret);
 169
 170 /**
 171  * block_job_enter:
 172  * @job: The job to enter.
 173  *
 174  * Continue the specified job by entering the coroutine.
 175  */
 176 void block_job_enter(BlockJob *job);
 177
 178 /**
 179  * block_job_event_ready:
 180  * @job: The job which is now ready to be completed.
 181  *
 182  * Send a BLOCK_JOB_READY event for the specified job.
 183  */
 184 void block_job_event_ready(BlockJob *job);
 185
 186 /**
 187  * block_job_error_action:
 188  * @job: The job to signal an error for.
 189  * @on_err: The error action setting.
 190  * @is_read: Whether the operation was a read.
 191  * @error: The error that was reported.
 192  *
 193  * Report an I/O error for a block job and possibly stop the VM.  Return the
 194  * action that was selected based on @on_err and @error.
 195  */
 196 BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
 197                                         int is_read, int error);
 198
 199 #endif