/*
* 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"
/**
* BlockJobDriver:
*
* A class type for block job driver.
*/
typedef struct BlockJobDriver {
/** Derived BlockJob struct size */
size_t instance_size;
/** String describing the operation, part of query-block-jobs QMP API */
BlockJobType 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);
/**
* If the callback is not NULL, it will be invoked when all the jobs
* belonging to the same transaction complete; or upon this job's
* completion if it is not in a transaction. Skipped if NULL.
*
* All jobs will complete with a call to either .commit() or .abort() but
* never both.
*/
void (*commit)(BlockJob *job);
/**
* If the callback is not NULL, it will be invoked when any job in the
* same transaction fails; or upon this job's failure (due to error or
* cancellation) if it is not in a transaction. Skipped if NULL.
*
* All jobs will complete with a call to either .commit() or .abort() but
* never both.
*/
void (*abort)(BlockJob *job);
} BlockJobDriver;
/**
* BlockJob:
*
* Long-running operation on a BlockDriverState.
*/
struct BlockJob {
/** The job type, including the job vtable. */
const BlockJobDriver *driver;
/** The block device on which the job is operating. */
BlockDriverState *bs;
/**
* The ID of the block job. Currently the BlockBackend name of the BDS
* owning the job at the time when the job is started.
*
* TODO Decouple block job IDs from BlockBackend names
*/
char *id;
/**
* 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 #aio_poll will ("sooner or later") reenter the coroutine.
*/
bool cancelled;
/**
* Counter for pause request. If non-zero, the block job is either paused,
* or if busy == true will pause itself as soon as possible.
*/
int pause_count;
/**
* Set to true if the job is paused by user. Can be unpaused with the
* block-job-resume QMP command.
*/
bool user_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 #aio_poll, such as a timer.
*/
bool busy;
/**
* Set to true when the job is ready to be completed.
*/
bool ready;
/**
* Set to true when the job has deferred work to the main loop.
*/
bool deferred_to_main_loop;
/** 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. */
BlockCompletionFunc *cb;
/** Block other operations when block job is running */
Error *blocker;
/** The opaque value that is passed to the completion function. */
void *opaque;
/** Reference count of the block job */
int refcnt;
/* True if this job has reported completion by calling block_job_completed.
*/
bool completed;
/* ret code passed to block_job_completed.
*/
int ret;
/** Non-NULL if this job is part of a transaction */
BlockJobTxn *txn;
QLIST_ENTRY(BlockJob) txn_list;
};
/**
* 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 BlockJobDriver *driver, BlockDriverState *bs,
int64_t speed, BlockCompletionFunc *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, QEMUClockType type, int64_t ns);
/**
* block_job_yield:
* @job: The job that calls the function.
*
* Yield the block job coroutine.
*/
void block_job_yield(BlockJob *job);
/**
* block_job_ref:
* @bs: The block device.
*
* Grab a reference to the block job. Should be paired with block_job_unref.
*/
void block_job_ref(BlockJob *job);
/**
* block_job_unref:
* @bs: The block device.
*
* Release reference to the block job and release resources if it is the last
* reference.
*/
void block_job_unref(BlockJob *job);
/**
* 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. Must be paired with a preceding block_job_pause.
*/
void block_job_resume(BlockJob *job);
/**
* block_job_enter:
* @job: The job to enter.
*
* Continue the specified job by entering the coroutine.
*/
void block_job_enter(BlockJob *job);
/**
* block_job_event_cancelled:
* @job: The job whose information is requested.
*
* Send a BLOCK_JOB_CANCELLED event for the specified job.
*/
void block_job_event_cancelled(BlockJob *job);
/**
* block_job_ready:
* @job: The job which is now ready to complete.
* @msg: Error message. Only present on failure.
*
* Send a BLOCK_JOB_COMPLETED event for the specified job.
*/
void block_job_event_completed(BlockJob *job, const char *msg);
/**
* 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_event_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_complete_sync:
* @job: The job to be completed.
* @errp: Error object which may be set by block_job_complete(); this is not
* necessarily set on every error, the job return value has to be
* checked as well.
*
* Synchronously complete the job. The completion callback is called before the
* function returns, unless it is NULL (which is permissible when using this
* function).
*
* Returns the return value from the job.
*/
int block_job_complete_sync(BlockJob *job, Error **errp);
/**
* 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.
* @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, BlockdevOnError on_err,
int is_read, int error);
typedef void BlockJobDeferToMainLoopFn(BlockJob *job, void *opaque);
/**
* block_job_defer_to_main_loop:
* @job: The job
* @fn: The function to run in the main loop
* @opaque: The opaque value that is passed to @fn
*
* Execute a given function in the main loop with the BlockDriverState
* AioContext acquired. Block jobs must call bdrv_unref(), bdrv_close(), and
* anything that uses bdrv_drain_all() in the main loop.
*
* The @job AioContext is held while @fn executes.
*/
void block_job_defer_to_main_loop(BlockJob *job,
BlockJobDeferToMainLoopFn *fn,
void *opaque);
/**
* block_job_txn_new:
*
* Allocate and return a new block job transaction. Jobs can be added to the
* transaction using block_job_txn_add_job().
*
* The transaction is automatically freed when the last job completes or is
* cancelled.
*
* All jobs in the transaction either complete successfully or fail/cancel as a
* group. Jobs wait for each other before completing. Cancelling one job
* cancels all jobs in the transaction.
*/
BlockJobTxn *block_job_txn_new(void);
/**
* block_job_txn_unref:
*
* Release a reference that was previously acquired with block_job_txn_add_job
* or block_job_txn_new. If it's the last reference to the object, it will be
* freed.
*/
void block_job_txn_unref(BlockJobTxn *txn);
/**
* block_job_txn_add_job:
* @txn: The transaction (may be NULL)
* @job: Job to add to the transaction
*
* Add @job to the transaction. The @job must not already be in a transaction.
* The caller must call either block_job_txn_unref() or block_job_completed()
* to release the reference that is automatically grabbed here.
*/
void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job);
#endif
