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
  31 /**
  32  * BlockJobDriver:
  33  *
  34  * A class type for block job driver.
  35  */
  36 struct BlockJobDriver {
  37     /** Generic JobDriver callbacks and settings */
  38     JobDriver job_driver;
  39
  40     /*
  41      * I/O API functions. These functions are thread-safe.
  42      *
  43      * See include/block/block-io.h for more information about
  44      * the I/O API.
  45      */
  46
  47     /*
  48      * Returns whether the job has pending requests for the child or will
  49      * submit new requests before the next pause point. This callback is polled
  50      * in the context of draining a job node after requesting that the job be
  51      * paused, until all activity on the child has stopped.
  52      */
  53     bool (*drained_poll)(BlockJob *job);
  54
  55     /*
  56      * Global state (GS) API. These functions run under the BQL.
  57      *
  58      * See include/block/block-global-state.h for more information about
  59      * the GS API.
  60      */
  61
  62     /*
  63      * If the callback is not NULL, it will be invoked before the job is
  64      * resumed in a new AioContext.  This is the place to move any resources
  65      * besides job->blk to the new AioContext.
  66      */
  67     void (*attached_aio_context)(BlockJob *job, AioContext *new_context);
  68
  69     void (*set_speed)(BlockJob *job, int64_t speed);
  70
  71     /*
  72      * Change the @job's options according to @opts.
  73      *
  74      * Note that this can already be called before the job coroutine is running.
  75      */
  76     void (*change)(BlockJob *job, BlockJobChangeOptions *opts, Error **errp);
  77
  78     /*
  79      * Query information specific to this kind of block job.
  80      */
  81     void (*query)(BlockJob *job, BlockJobInfo *info);
  82 };
  83
  84 /*
  85  * Global state (GS) API. These functions run under the BQL.
  86  *
  87  * See include/block/block-global-state.h for more information about
  88  * the GS API.
  89  */
  90
  91 /**
  92  * block_job_create:
  93  * @job_id: The id of the newly-created job, or %NULL to have one
  94  * generated automatically.
  95  * @driver: The class object for the newly-created job.
  96  * @txn: The transaction this job belongs to, if any. %NULL otherwise.
  97  * @bs: The block
  98  * @perm, @shared_perm: Permissions to request for @bs
  99  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 100  * @flags: Creation flags for the Block Job. See @JobCreateFlags.
 101  * @cb: Completion function for the job.
 102  * @opaque: Opaque pointer value passed to @cb.
 103  * @errp: Error object.
 104  *
 105  * Create a new long-running block device job and return it.  The job
 106  * will call @cb asynchronously when the job completes.  Note that
 107  * @bs may have been closed at the time the @cb it is called.  If
 108  * this is the case, the job may be reported as either cancelled or
 109  * completed.
 110  *
 111  * This function is not part of the public job interface; it should be
 112  * called from a wrapper that is specific to the job type.
 113  */
 114 void * GRAPH_UNLOCKED
 115 block_job_create(const char *job_id, const BlockJobDriver *driver,
 116                  JobTxn *txn, BlockDriverState *bs, uint64_t perm,
 117                  uint64_t shared_perm, int64_t speed, int flags,
 118                  BlockCompletionFunc *cb, void *opaque, Error **errp);
 119
 120 /**
 121  * block_job_free:
 122  * Callback to be used for JobDriver.free in all block jobs. Frees block job
 123  * specific resources in @job.
 124  */
 125 void block_job_free(Job *job);
 126
 127 /**
 128  * block_job_user_resume:
 129  * Callback to be used for JobDriver.user_resume in all block jobs. Resets the
 130  * iostatus when the user resumes @job.
 131  */
 132 void block_job_user_resume(Job *job);
 133
 134 /*
 135  * I/O API functions. These functions are thread-safe.
 136  *
 137  * See include/block/block-io.h for more information about
 138  * the I/O API.
 139  */
 140
 141 /**
 142  * block_job_ratelimit_processed_bytes:
 143  *
 144  * To be called after some work has been done. Adjusts the delay for the next
 145  * request. See the documentation of ratelimit_calculate_delay() for details.
 146  */
 147 void block_job_ratelimit_processed_bytes(BlockJob *job, uint64_t n);
 148
 149 /**
 150  * Put the job to sleep (assuming that it wasn't canceled) to throttle it to the
 151  * right speed according to its rate limiting.
 152  */
 153 void block_job_ratelimit_sleep(BlockJob *job);
 154
 155 /**
 156  * block_job_error_action:
 157  * @job: The job to signal an error for.
 158  * @on_err: The error action setting.
 159  * @is_read: Whether the operation was a read.
 160  * @error: The error that was reported.
 161  *
 162  * Report an I/O error for a block job and possibly stop the VM.  Return the
 163  * action that was selected based on @on_err and @error.
 164  */
 165 BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
 166                                         int is_read, int error);
 167
 168 #endif