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
  31/**
  32 * BlockJobDriver:
  33 *
  34 * A class type for block job driver.
  35 */
  36struct 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/*
  73 * Global state (GS) API. These functions run under the BQL.
  74 *
  75 * See include/block/block-global-state.h for more information about
  76 * the GS API.
  77 */
  78
  79/**
  80 * block_job_create:
  81 * @job_id: The id of the newly-created job, or %NULL to have one
  82 * generated automatically.
  83 * @driver: The class object for the newly-created job.
  84 * @txn: The transaction this job belongs to, if any. %NULL otherwise.
  85 * @bs: The block
  86 * @perm, @shared_perm: Permissions to request for @bs
  87 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
  88 * @flags: Creation flags for the Block Job. See @JobCreateFlags.
  89 * @cb: Completion function for the job.
  90 * @opaque: Opaque pointer value passed to @cb.
  91 * @errp: Error object.
  92 *
  93 * Create a new long-running block device job and return it.  The job
  94 * will call @cb asynchronously when the job completes.  Note that
  95 * @bs may have been closed at the time the @cb it is called.  If
  96 * this is the case, the job may be reported as either cancelled or
  97 * completed.
  98 *
  99 * This function is not part of the public job interface; it should be
 100 * called from a wrapper that is specific to the job type.
 101 */
 102void *block_job_create(const char *job_id, const BlockJobDriver *driver,
 103                       JobTxn *txn, BlockDriverState *bs, uint64_t perm,
 104                       uint64_t shared_perm, int64_t speed, int flags,
 105                       BlockCompletionFunc *cb, void *opaque, Error **errp);
 106
 107/**
 108 * block_job_free:
 109 * Callback to be used for JobDriver.free in all block jobs. Frees block job
 110 * specific resources in @job.
 111 */
 112void block_job_free(Job *job);
 113
 114/**
 115 * block_job_user_resume:
 116 * Callback to be used for JobDriver.user_resume in all block jobs. Resets the
 117 * iostatus when the user resumes @job.
 118 */
 119void block_job_user_resume(Job *job);
 120
 121/*
 122 * I/O API functions. These functions are thread-safe.
 123 *
 124 * See include/block/block-io.h for more information about
 125 * the I/O API.
 126 */
 127
 128/**
 129 * block_job_ratelimit_processed_bytes:
 130 *
 131 * To be called after some work has been done. Adjusts the delay for the next
 132 * request. See the documentation of ratelimit_calculate_delay() for details.
 133 */
 134void block_job_ratelimit_processed_bytes(BlockJob *job, uint64_t n);
 135
 136/**
 137 * Put the job to sleep (assuming that it wasn't canceled) to throttle it to the
 138 * right speed according to its rate limiting.
 139 */
 140void block_job_ratelimit_sleep(BlockJob *job);
 141
 142/**
 143 * block_job_error_action:
 144 * @job: The job to signal an error for.
 145 * @on_err: The error action setting.
 146 * @is_read: Whether the operation was a read.
 147 * @error: The error that was reported.
 148 *
 149 * Report an I/O error for a block job and possibly stop the VM.  Return the
 150 * action that was selected based on @on_err and @error.
 151 */
 152BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
 153                                        int is_read, int error);
 154
 155#endif
 156