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      * Returns whether the job has pending requests for the child or will
  43      * submit new requests before the next pause point. This callback is polled
  44      * in the context of draining a job node after requesting that the job be
  45      * paused, until all activity on the child has stopped.
  46      */
  47     bool (*drained_poll)(BlockJob *job);
  48
  49     /*
  50      * If the callback is not NULL, it will be invoked before the job is
  51      * resumed in a new AioContext.  This is the place to move any resources
  52      * besides job->blk to the new AioContext.
  53      */
  54     void (*attached_aio_context)(BlockJob *job, AioContext *new_context);
  55 };
  56
  57 /**
  58  * block_job_create:
  59  * @job_id: The id of the newly-created job, or %NULL to have one
  60  * generated automatically.
  61  * @driver: The class object for the newly-created job.
  62  * @txn: The transaction this job belongs to, if any. %NULL otherwise.
  63  * @bs: The block
  64  * @perm, @shared_perm: Permissions to request for @bs
  65  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
  66  * @flags: Creation flags for the Block Job. See @JobCreateFlags.
  67  * @cb: Completion function for the job.
  68  * @opaque: Opaque pointer value passed to @cb.
  69  * @errp: Error object.
  70  *
  71  * Create a new long-running block device job and return it.  The job
  72  * will call @cb asynchronously when the job completes.  Note that
  73  * @bs may have been closed at the time the @cb it is called.  If
  74  * this is the case, the job may be reported as either cancelled or
  75  * completed.
  76  *
  77  * This function is not part of the public job interface; it should be
  78  * called from a wrapper that is specific to the job type.
  79  */
  80 void *block_job_create(const char *job_id, const BlockJobDriver *driver,
  81                        JobTxn *txn, BlockDriverState *bs, uint64_t perm,
  82                        uint64_t shared_perm, int64_t speed, int flags,
  83                        BlockCompletionFunc *cb, void *opaque, Error **errp);
  84
  85 /**
  86  * block_job_free:
  87  * Callback to be used for JobDriver.free in all block jobs. Frees block job
  88  * specific resources in @job.
  89  */
  90 void block_job_free(Job *job);
  91
  92 /**
  93  * block_job_user_resume:
  94  * Callback to be used for JobDriver.user_resume in all block jobs. Resets the
  95  * iostatus when the user resumes @job.
  96  */
  97 void block_job_user_resume(Job *job);
  98
  99 /**
 100  * block_job_ratelimit_get_delay:
 101  *
 102  * Calculate and return delay for the next request in ns. See the documentation
 103  * of ratelimit_calculate_delay() for details.
 104  */
 105 int64_t block_job_ratelimit_get_delay(BlockJob *job, uint64_t n);
 106
 107 /**
 108  * block_job_error_action:
 109  * @job: The job to signal an error for.
 110  * @on_err: The error action setting.
 111  * @is_read: Whether the operation was a read.
 112  * @error: The error that was reported.
 113  *
 114  * Report an I/O error for a block job and possibly stop the VM.  Return the
 115  * action that was selected based on @on_err and @error.
 116  */
 117 BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
 118                                         int is_read, int error);
 119
 120 #endif