LXR qemu/include/block/blockjob

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