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     * 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     * If the callback is not NULL, it will be invoked when the job has to be
  58     * synchronously cancelled or completed; it should drain BlockDriverStates
  59     * as required to ensure progress.
  60     *
  61     * Block jobs must use the default implementation for job_driver.drain,
  62     * which will in turn call this callback after doing generic block job
  63     * stuff.
  64     */
  65    void (*drain)(BlockJob *job);
  66};
  67
  68/**
  69 * block_job_create:
  70 * @job_id: The id of the newly-created job, or %NULL to have one
  71 * generated automatically.
  72 * @driver: The class object for the newly-created job.
  73 * @txn: The transaction this job belongs to, if any. %NULL otherwise.
  74 * @bs: The block
  75 * @perm, @shared_perm: Permissions to request for @bs
  76 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
  77 * @flags: Creation flags for the Block Job. See @JobCreateFlags.
  78 * @cb: Completion function for the job.
  79 * @opaque: Opaque pointer value passed to @cb.
  80 * @errp: Error object.
  81 *
  82 * Create a new long-running block device job and return it.  The job
  83 * will call @cb asynchronously when the job completes.  Note that
  84 * @bs may have been closed at the time the @cb it is called.  If
  85 * this is the case, the job may be reported as either cancelled or
  86 * completed.
  87 *
  88 * This function is not part of the public job interface; it should be
  89 * called from a wrapper that is specific to the job type.
  90 */
  91void *block_job_create(const char *job_id, const BlockJobDriver *driver,
  92                       JobTxn *txn, BlockDriverState *bs, uint64_t perm,
  93                       uint64_t shared_perm, int64_t speed, int flags,
  94                       BlockCompletionFunc *cb, void *opaque, Error **errp);
  95
  96/**
  97 * block_job_free:
  98 * Callback to be used for JobDriver.free in all block jobs. Frees block job
  99 * specific resources in @job.
 100 */
 101void block_job_free(Job *job);
 102
 103/**
 104 * block_job_user_resume:
 105 * Callback to be used for JobDriver.user_resume in all block jobs. Resets the
 106 * iostatus when the user resumes @job.
 107 */
 108void block_job_user_resume(Job *job);
 109
 110/**
 111 * block_job_drain:
 112 * Callback to be used for JobDriver.drain in all block jobs. Drains the main
 113 * block node associated with the block jobs and calls BlockJobDriver.drain for
 114 * job-specific actions.
 115 */
 116void block_job_drain(Job *job);
 117
 118/**
 119 * block_job_ratelimit_get_delay:
 120 *
 121 * Calculate and return delay for the next request in ns. See the documentation
 122 * of ratelimit_calculate_delay() for details.
 123 */
 124int64_t block_job_ratelimit_get_delay(BlockJob *job, uint64_t n);
 125
 126/**
 127 * block_job_error_action:
 128 * @job: The job to signal an error for.
 129 * @on_err: The error action setting.
 130 * @is_read: Whether the operation was a read.
 131 * @error: The error that was reported.
 132 *
 133 * Report an I/O error for a block job and possibly stop the VM.  Return the
 134 * action that was selected based on @on_err and @error.
 135 */
 136BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
 137                                        int is_read, int error);
 138
 139#endif
 140