Archipelago » qemu

/*

 * Declarations for long-running block device operations

 *

 * Copyright (c) 2011 IBM Corp.

 * Copyright (c) 2012 Red Hat, Inc.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#ifndef BLOCKJOB_H

#define BLOCKJOB_H 1

#include "block/block.h"

/**

 * BlockJobType:

 *

 * A class type for block job objects.

 */

typedef struct BlockJobType {

    /** Derived BlockJob struct size */

    size_t instance_size;

    /** String describing the operation, part of query-block-jobs QMP API */

    const char *job_type;

    /** Optional callback for job types that support setting a speed limit */

    void (*set_speed)(BlockJob *job, int64_t speed, Error **errp);

    /** Optional callback for job types that need to forward I/O status reset */

    void (*iostatus_reset)(BlockJob *job);

    /**

     * Optional callback for job types whose completion must be triggered

     * manually.

     */

    void (*complete)(BlockJob *job, Error **errp);

} BlockJobType;

/**

 * BlockJob:

 *

 * Long-running operation on a BlockDriverState.

 */

struct BlockJob {

    /** The job type, including the job vtable.  */

    const BlockJobType *job_type;

    /** The block device on which the job is operating.  */

    BlockDriverState *bs;

    /**

     * The coroutine that executes the job.  If not NULL, it is

     * reentered when busy is false and the job is cancelled.

     */

    Coroutine *co;

    /**

     * Set to true if the job should cancel itself.  The flag must

     * always be tested just before toggling the busy flag from false

     * to true.  After a job has been cancelled, it should only yield

     * if #qemu_aio_wait will ("sooner or later") reenter the coroutine.

     */

    bool cancelled;

    /**

     * Set to true if the job is either paused, or will pause itself

     * as soon as possible (if busy == true).

     */

    bool paused;

    /**

     * Set to false by the job while it is in a quiescent state, where

     * no I/O is pending and the job has yielded on any condition

     * that is not detected by #qemu_aio_wait, such as a timer.

     */

    bool busy;

    /** Status that is published by the query-block-jobs QMP API */

    BlockDeviceIoStatus iostatus;

    /** Offset that is published by the query-block-jobs QMP API */

    int64_t offset;

    /** Length that is published by the query-block-jobs QMP API */

    int64_t len;

    /** Speed that was set with @block_job_set_speed.  */

    int64_t speed;

    /** The completion function that will be called when the job completes.  */

    BlockDriverCompletionFunc *cb;

    /** The opaque value that is passed to the completion function.  */

    void *opaque;

};

/**

 * block_job_create:

 * @job_type: The class object for the newly-created job.

 * @bs: The block

 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.

 * @cb: Completion function for the job.

 * @opaque: Opaque pointer value passed to @cb.

 * @errp: Error object.

 *

 * Create a new long-running block device job and return it.  The job

 * will call @cb asynchronously when the job completes.  Note that

 * @bs may have been closed at the time the @cb it is called.  If

 * this is the case, the job may be reported as either cancelled or

 * completed.

 *

 * This function is not part of the public job interface; it should be

 * called from a wrapper that is specific to the job type.

 */

void *block_job_create(const BlockJobType *job_type, BlockDriverState *bs,

                       int64_t speed, BlockDriverCompletionFunc *cb,

                       void *opaque, Error **errp);

/**

 * block_job_sleep_ns:

 * @job: The job that calls the function.

 * @clock: The clock to sleep on.

 * @ns: How many nanoseconds to stop for.

 *

 * Put the job to sleep (assuming that it wasn't canceled) for @ns

 * nanoseconds.  Canceling the job will interrupt the wait immediately.

 */

void block_job_sleep_ns(BlockJob *job, QEMUClock *clock, int64_t ns);

/**

 * block_job_completed:

 * @job: The job being completed.

 * @ret: The status code.

 *

 * Call the completion function that was registered at creation time, and

 * free @job.

 */

void block_job_completed(BlockJob *job, int ret);

/**

 * block_job_set_speed:

 * @job: The job to set the speed for.

 * @speed: The new value

 * @errp: Error object.

 *

 * Set a rate-limiting parameter for the job; the actual meaning may

 * vary depending on the job type.

 */

void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp);

/**

 * block_job_cancel:

 * @job: The job to be canceled.

 *

 * Asynchronously cancel the specified job.

 */

void block_job_cancel(BlockJob *job);

/**

 * block_job_complete:

 * @job: The job to be completed.

 * @errp: Error object.

 *

 * Asynchronously complete the specified job.

 */

void block_job_complete(BlockJob *job, Error **errp);

/**

 * block_job_is_cancelled:

 * @job: The job being queried.

 *

 * Returns whether the job is scheduled for cancellation.

 */

bool block_job_is_cancelled(BlockJob *job);

/**

 * block_job_query:

 * @job: The job to get information about.

 *

 * Return information about a job.

 */

BlockJobInfo *block_job_query(BlockJob *job);

/**

 * block_job_pause:

 * @job: The job to be paused.

 *

 * Asynchronously pause the specified job.

 */

void block_job_pause(BlockJob *job);

/**

 * block_job_resume:

 * @job: The job to be resumed.

 *

 * Resume the specified job.

 */

void block_job_resume(BlockJob *job);

/**

 * qobject_from_block_job:

 * @job: The job whose information is requested.

 *

 * Return a QDict corresponding to @job's query-block-jobs entry.

 */

QObject *qobject_from_block_job(BlockJob *job);

/**

 * block_job_ready:

 * @job: The job which is now ready to complete.

 *

 * Send a BLOCK_JOB_READY event for the specified job.

 */

void block_job_ready(BlockJob *job);

/**

 * block_job_is_paused:

 * @job: The job being queried.

 *

 * Returns whether the job is currently paused, or will pause

 * as soon as it reaches a sleeping point.

 */

bool block_job_is_paused(BlockJob *job);

/**

 * block_job_cancel_sync:

 * @job: The job to be canceled.

 *

 * Synchronously cancel the job.  The completion callback is called

 * before the function returns.  The job may actually complete

 * instead of canceling itself; the circumstances under which this

 * happens depend on the kind of job that is active.

 *

 * Returns the return value from the job if the job actually completed

 * during the call, or -ECANCELED if it was canceled.

 */

int block_job_cancel_sync(BlockJob *job);

/**

 * block_job_iostatus_reset:

 * @job: The job whose I/O status should be reset.

 *

 * Reset I/O status on @job and on BlockDriverState objects it uses,

 * other than job->bs.

 */

void block_job_iostatus_reset(BlockJob *job);

/**

 * block_job_error_action:

 * @job: The job to signal an error for.

 * @bs: The block device on which to set an I/O error.

 * @on_err: The error action setting.

 * @is_read: Whether the operation was a read.

 * @error: The error that was reported.

 *

 * Report an I/O error for a block job and possibly stop the VM.  Return the

 * action that was selected based on @on_err and @error.

 */

BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,

                                        BlockdevOnError on_err,

                                        int is_read, int error);

#endif