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 before the job is
  59      * resumed in a new AioContext.  This is the place to move any resources
  60      * besides job->blk to the new AioContext.
  61      */
  62     void (*attached_aio_context)(BlockJob *job, AioContext *new_context);
  63
  64     /*
  65      * If the callback is not NULL, it will be invoked when the job has to be
  66      * synchronously cancelled or completed; it should drain BlockDriverStates
  67      * as required to ensure progress.
  68      */
  69     void (*drain)(BlockJob *job);
  70 };
  71
  72 /**
  73  * block_job_create:
  74  * @job_id: The id of the newly-created job, or %NULL to have one
  75  * generated automatically.
  76  * @driver: The class object for the newly-created job.
  77  * @txn: The transaction this job belongs to, if any. %NULL otherwise.
  78  * @bs: The block
  79  * @perm, @shared_perm: Permissions to request for @bs
  80  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
  81  * @flags: Creation flags for the Block Job. See @JobCreateFlags.
  82  * @cb: Completion function for the job.
  83  * @opaque: Opaque pointer value passed to @cb.
  84  * @errp: Error object.
  85  *
  86  * Create a new long-running block device job and return it.  The job
  87  * will call @cb asynchronously when the job completes.  Note that
  88  * @bs may have been closed at the time the @cb it is called.  If
  89  * this is the case, the job may be reported as either cancelled or
  90  * completed.
  91  *
  92  * This function is not part of the public job interface; it should be
  93  * called from a wrapper that is specific to the job type.
  94  */
  95 void *block_job_create(const char *job_id, const BlockJobDriver *driver,
  96                        BlockJobTxn *txn, BlockDriverState *bs, uint64_t perm,
  97                        uint64_t shared_perm, int64_t speed, int flags,
  98                        BlockCompletionFunc *cb, void *opaque, Error **errp);
  99
 100 /**
 101  * block_job_free:
 102  * Callback to be used for JobDriver.free in all block jobs. Frees block job
 103  * specific resources in @job.
 104  */
 105 void block_job_free(Job *job);
 106
 107 /**
 108  * block_job_user_resume:
 109  * Callback to be used for JobDriver.user_resume in all block jobs. Resets the
 110  * iostatus when the user resumes @job.
 111  */
 112 void block_job_user_resume(Job *job);
 113
 114 /**
 115  * block_job_yield:
 116  * @job: The job that calls the function.
 117  *
 118  * Yield the block job coroutine.
 119  */
 120 void block_job_yield(BlockJob *job);
 121
 122 /**
 123  * block_job_ratelimit_get_delay:
 124  *
 125  * Calculate and return delay for the next request in ns. See the documentation
 126  * of ratelimit_calculate_delay() for details.
 127  */
 128 int64_t block_job_ratelimit_get_delay(BlockJob *job, uint64_t n);
 129
 130 /**
 131  * block_job_completed:
 132  * @job: The job being completed.
 133  * @ret: The status code.
 134  *
 135  * Call the completion function that was registered at creation time, and
 136  * free @job.
 137  */
 138 void block_job_completed(BlockJob *job, int ret);
 139
 140 /**
 141  * block_job_enter:
 142  * @job: The job to enter.
 143  *
 144  * Continue the specified job by entering the coroutine.
 145  */
 146 void block_job_enter(BlockJob *job);
 147
 148 /**
 149  * block_job_event_ready:
 150  * @job: The job which is now ready to be completed.
 151  *
 152  * Send a BLOCK_JOB_READY event for the specified job.
 153  */
 154 void block_job_event_ready(BlockJob *job);
 155
 156 /**
 157  * block_job_error_action:
 158  * @job: The job to signal an error for.
 159  * @on_err: The error action setting.
 160  * @is_read: Whether the operation was a read.
 161  * @error: The error that was reported.
 162  *
 163  * Report an I/O error for a block job and possibly stop the VM.  Return the
 164  * action that was selected based on @on_err and @error.
 165  */
 166 BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
 167                                         int is_read, int error);
 168
 169 #endif