567 lines
18 KiB
C
567 lines
18 KiB
C
/*
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* Declarations for background jobs
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*
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* Copyright (c) 2011 IBM Corp.
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* Copyright (c) 2012, 2018 Red Hat, Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifndef JOB_H
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#define JOB_H
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#include "qapi/qapi-types-job.h"
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#include "qemu/queue.h"
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#include "qemu/progress_meter.h"
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#include "qemu/coroutine.h"
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#include "block/aio.h"
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typedef struct JobDriver JobDriver;
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typedef struct JobTxn JobTxn;
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/**
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* Long-running operation.
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*/
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typedef struct Job {
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/** The ID of the job. May be NULL for internal jobs. */
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char *id;
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/** The type of this job. */
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const JobDriver *driver;
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/** Reference count of the block job */
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int refcnt;
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/** Current state; See @JobStatus for details. */
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JobStatus status;
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/** AioContext to run the job coroutine in */
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AioContext *aio_context;
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/**
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* The coroutine that executes the job. If not NULL, it is reentered when
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* busy is false and the job is cancelled.
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*/
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Coroutine *co;
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/**
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* Timer that is used by @job_sleep_ns. Accessed under job_mutex (in
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* job.c).
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*/
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QEMUTimer sleep_timer;
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/**
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* Counter for pause request. If non-zero, the block job is either paused,
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* or if busy == true will pause itself as soon as possible.
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*/
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int pause_count;
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/**
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* Set to false by the job while the coroutine has yielded and may be
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* re-entered by job_enter(). There may still be I/O or event loop activity
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* pending. Accessed under block_job_mutex (in blockjob.c).
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*
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* When the job is deferred to the main loop, busy is true as long as the
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* bottom half is still pending.
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*/
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bool busy;
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/**
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* Set to true by the job while it is in a quiescent state, where
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* no I/O or event loop activity is pending.
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*/
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bool paused;
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/**
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* Set to true if the job is paused by user. Can be unpaused with the
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* block-job-resume QMP command.
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*/
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bool user_paused;
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/**
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* Set to true if the job should cancel itself. The flag must
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* always be tested just before toggling the busy flag from false
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* to true. After a job has been cancelled, it should only yield
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* if #aio_poll will ("sooner or later") reenter the coroutine.
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*/
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bool cancelled;
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/**
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* Set to true if the job should abort immediately without waiting
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* for data to be in sync.
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*/
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bool force_cancel;
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/** Set to true when the job has deferred work to the main loop. */
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bool deferred_to_main_loop;
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/** True if this job should automatically finalize itself */
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bool auto_finalize;
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/** True if this job should automatically dismiss itself */
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bool auto_dismiss;
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ProgressMeter progress;
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/**
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* Return code from @run and/or @prepare callback(s).
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* Not final until the job has reached the CONCLUDED status.
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* 0 on success, -errno on failure.
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*/
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int ret;
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/**
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* Error object for a failed job.
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* If job->ret is nonzero and an error object was not set, it will be set
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* to strerror(-job->ret) during job_completed.
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*/
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Error *err;
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/** The completion function that will be called when the job completes. */
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BlockCompletionFunc *cb;
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/** The opaque value that is passed to the completion function. */
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void *opaque;
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/** Notifiers called when a cancelled job is finalised */
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NotifierList on_finalize_cancelled;
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/** Notifiers called when a successfully completed job is finalised */
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NotifierList on_finalize_completed;
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/** Notifiers called when the job transitions to PENDING */
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NotifierList on_pending;
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/** Notifiers called when the job transitions to READY */
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NotifierList on_ready;
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/** Notifiers called when the job coroutine yields or terminates */
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NotifierList on_idle;
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/** Element of the list of jobs */
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QLIST_ENTRY(Job) job_list;
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/** Transaction this job is part of */
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JobTxn *txn;
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/** Element of the list of jobs in a job transaction */
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QLIST_ENTRY(Job) txn_list;
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} Job;
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/**
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* Callbacks and other information about a Job driver.
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*/
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struct JobDriver {
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/** Derived Job struct size */
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size_t instance_size;
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/** Enum describing the operation */
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JobType job_type;
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/**
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* Mandatory: Entrypoint for the Coroutine.
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*
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* This callback will be invoked when moving from CREATED to RUNNING.
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*
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* If this callback returns nonzero, the job transaction it is part of is
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* aborted. If it returns zero, the job moves into the WAITING state. If it
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* is the last job to complete in its transaction, all jobs in the
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* transaction move from WAITING to PENDING.
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*/
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int coroutine_fn (*run)(Job *job, Error **errp);
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/**
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* If the callback is not NULL, it will be invoked when the job transitions
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* into the paused state. Paused jobs must not perform any asynchronous
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* I/O or event loop activity. This callback is used to quiesce jobs.
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*/
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void coroutine_fn (*pause)(Job *job);
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/**
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* If the callback is not NULL, it will be invoked when the job transitions
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* out of the paused state. Any asynchronous I/O or event loop activity
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* should be restarted from this callback.
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*/
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void coroutine_fn (*resume)(Job *job);
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/**
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* Called when the job is resumed by the user (i.e. user_paused becomes
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* false). .user_resume is called before .resume.
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*/
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void (*user_resume)(Job *job);
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/**
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* Optional callback for job types whose completion must be triggered
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* manually.
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*/
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void (*complete)(Job *job, Error **errp);
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/**
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* If the callback is not NULL, prepare will be invoked when all the jobs
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* belonging to the same transaction complete; or upon this job's completion
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* if it is not in a transaction.
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*
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* This callback will not be invoked if the job has already failed.
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* If it fails, abort and then clean will be called.
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*/
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int (*prepare)(Job *job);
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/**
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* If the callback is not NULL, it will be invoked when all the jobs
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* belonging to the same transaction complete; or upon this job's
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* completion if it is not in a transaction. Skipped if NULL.
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*
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* All jobs will complete with a call to either .commit() or .abort() but
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* never both.
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*/
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void (*commit)(Job *job);
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/**
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* If the callback is not NULL, it will be invoked when any job in the
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* same transaction fails; or upon this job's failure (due to error or
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* cancellation) if it is not in a transaction. Skipped if NULL.
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*
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* All jobs will complete with a call to either .commit() or .abort() but
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* never both.
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*/
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void (*abort)(Job *job);
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/**
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* If the callback is not NULL, it will be invoked after a call to either
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* .commit() or .abort(). Regardless of which callback is invoked after
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* completion, .clean() will always be called, even if the job does not
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* belong to a transaction group.
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*/
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void (*clean)(Job *job);
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/**
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* If the callback is not NULL, it will be invoked in job_cancel_async
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*/
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void (*cancel)(Job *job, bool force);
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/** Called when the job is freed */
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void (*free)(Job *job);
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};
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typedef enum JobCreateFlags {
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/* Default behavior */
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JOB_DEFAULT = 0x00,
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/* Job is not QMP-created and should not send QMP events */
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JOB_INTERNAL = 0x01,
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/* Job requires manual finalize step */
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JOB_MANUAL_FINALIZE = 0x02,
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/* Job requires manual dismiss step */
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JOB_MANUAL_DISMISS = 0x04,
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} JobCreateFlags;
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/**
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* Allocate and return a new job transaction. Jobs can be added to the
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* transaction using job_txn_add_job().
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*
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* The transaction is automatically freed when the last job completes or is
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* cancelled.
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*
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* All jobs in the transaction either complete successfully or fail/cancel as a
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* group. Jobs wait for each other before completing. Cancelling one job
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* cancels all jobs in the transaction.
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*/
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JobTxn *job_txn_new(void);
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/**
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* Release a reference that was previously acquired with job_txn_add_job or
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* job_txn_new. If it's the last reference to the object, it will be freed.
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*/
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void job_txn_unref(JobTxn *txn);
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/**
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* @txn: The transaction (may be NULL)
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* @job: Job to add to the transaction
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*
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* Add @job to the transaction. The @job must not already be in a transaction.
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* The caller must call either job_txn_unref() or job_completed() to release
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* the reference that is automatically grabbed here.
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*
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* If @txn is NULL, the function does nothing.
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*/
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void job_txn_add_job(JobTxn *txn, Job *job);
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/**
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* Create a new long-running job and return it.
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*
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* @job_id: The id of the newly-created job, or %NULL for internal jobs
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* @driver: The class object for the newly-created job.
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* @txn: The transaction this job belongs to, if any. %NULL otherwise.
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* @ctx: The AioContext to run the job coroutine in.
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* @flags: Creation flags for the job. See @JobCreateFlags.
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* @cb: Completion function for the job.
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* @opaque: Opaque pointer value passed to @cb.
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* @errp: Error object.
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*/
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void *job_create(const char *job_id, const JobDriver *driver, JobTxn *txn,
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AioContext *ctx, int flags, BlockCompletionFunc *cb,
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void *opaque, Error **errp);
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/**
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* Add a reference to Job refcnt, it will be decreased with job_unref, and then
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* be freed if it comes to be the last reference.
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*/
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void job_ref(Job *job);
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/**
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* Release a reference that was previously acquired with job_ref() or
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* job_create(). If it's the last reference to the object, it will be freed.
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*/
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void job_unref(Job *job);
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/**
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* @job: The job that has made progress
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* @done: How much progress the job made since the last call
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*
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* Updates the progress counter of the job.
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*/
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void job_progress_update(Job *job, uint64_t done);
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/**
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* @job: The job whose expected progress end value is set
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* @remaining: Missing progress (on top of the current progress counter value)
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* until the new expected end value is reached
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*
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* Sets the expected end value of the progress counter of a job so that a
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* completion percentage can be calculated when the progress is updated.
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*/
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void job_progress_set_remaining(Job *job, uint64_t remaining);
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/**
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* @job: The job whose expected progress end value is updated
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* @delta: Value which is to be added to the current expected end
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* value
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*
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* Increases the expected end value of the progress counter of a job.
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* This is useful for parenthesis operations: If a job has to
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* conditionally perform a high-priority operation as part of its
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* progress, it calls this function with the expected operation's
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* length before, and job_progress_update() afterwards.
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* (So the operation acts as a parenthesis in regards to the main job
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* operation running in background.)
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*/
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void job_progress_increase_remaining(Job *job, uint64_t delta);
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/** To be called when a cancelled job is finalised. */
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void job_event_cancelled(Job *job);
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/** To be called when a successfully completed job is finalised. */
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void job_event_completed(Job *job);
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/**
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* Conditionally enter the job coroutine if the job is ready to run, not
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* already busy and fn() returns true. fn() is called while under the job_lock
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* critical section.
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*/
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void job_enter_cond(Job *job, bool(*fn)(Job *job));
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/**
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* @job: A job that has not yet been started.
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*
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* Begins execution of a job.
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* Takes ownership of one reference to the job object.
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*/
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void job_start(Job *job);
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/**
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* @job: The job to enter.
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*
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* Continue the specified job by entering the coroutine.
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*/
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void job_enter(Job *job);
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/**
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* @job: The job that is ready to pause.
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*
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* Pause now if job_pause() has been called. Jobs that perform lots of I/O
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* must call this between requests so that the job can be paused.
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*/
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void coroutine_fn job_pause_point(Job *job);
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/**
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* @job: The job that calls the function.
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*
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* Yield the job coroutine.
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*/
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void job_yield(Job *job);
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/**
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* @job: The job that calls the function.
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* @ns: How many nanoseconds to stop for.
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*
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* Put the job to sleep (assuming that it wasn't canceled) for @ns
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* %QEMU_CLOCK_REALTIME nanoseconds. Canceling the job will immediately
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* interrupt the wait.
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*/
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void coroutine_fn job_sleep_ns(Job *job, int64_t ns);
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/** Returns the JobType of a given Job. */
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JobType job_type(const Job *job);
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/** Returns the enum string for the JobType of a given Job. */
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const char *job_type_str(const Job *job);
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/** Returns true if the job should not be visible to the management layer. */
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bool job_is_internal(Job *job);
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/** Returns whether the job is scheduled for cancellation. */
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bool job_is_cancelled(Job *job);
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/** Returns whether the job is in a completed state. */
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bool job_is_completed(Job *job);
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/** Returns whether the job is ready to be completed. */
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bool job_is_ready(Job *job);
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/**
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* Request @job to pause at the next pause point. Must be paired with
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* job_resume(). If the job is supposed to be resumed by user action, call
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* job_user_pause() instead.
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*/
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void job_pause(Job *job);
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/** Resumes a @job paused with job_pause. */
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void job_resume(Job *job);
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/**
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* Asynchronously pause the specified @job.
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* Do not allow a resume until a matching call to job_user_resume.
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*/
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void job_user_pause(Job *job, Error **errp);
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/** Returns true if the job is user-paused. */
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bool job_user_paused(Job *job);
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/**
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* Resume the specified @job.
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* Must be paired with a preceding job_user_pause.
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*/
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void job_user_resume(Job *job, Error **errp);
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/**
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* Get the next element from the list of block jobs after @job, or the
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* first one if @job is %NULL.
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*
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* Returns the requested job, or %NULL if there are no more jobs left.
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*/
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Job *job_next(Job *job);
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/**
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* Get the job identified by @id (which must not be %NULL).
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*
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* Returns the requested job, or %NULL if it doesn't exist.
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*/
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Job *job_get(const char *id);
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/**
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* Check whether the verb @verb can be applied to @job in its current state.
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* Returns 0 if the verb can be applied; otherwise errp is set and -EPERM
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* returned.
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*/
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int job_apply_verb(Job *job, JobVerb verb, Error **errp);
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/** The @job could not be started, free it. */
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void job_early_fail(Job *job);
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/** Moves the @job from RUNNING to READY */
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void job_transition_to_ready(Job *job);
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/** Asynchronously complete the specified @job. */
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void job_complete(Job *job, Error **errp);
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/**
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* Asynchronously cancel the specified @job. If @force is true, the job should
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* be cancelled immediately without waiting for a consistent state.
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*/
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void job_cancel(Job *job, bool force);
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/**
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* Cancels the specified job like job_cancel(), but may refuse to do so if the
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* operation isn't meaningful in the current state of the job.
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*/
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void job_user_cancel(Job *job, bool force, Error **errp);
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/**
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* Synchronously cancel the @job. The completion callback is called
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* before the function returns. The job may actually complete
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* instead of canceling itself; the circumstances under which this
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* happens depend on the kind of job that is active.
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*
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* Returns the return value from the job if the job actually completed
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* during the call, or -ECANCELED if it was canceled.
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*
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* Callers must hold the AioContext lock of job->aio_context.
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*/
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int job_cancel_sync(Job *job);
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/** Synchronously cancels all jobs using job_cancel_sync(). */
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void job_cancel_sync_all(void);
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/**
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* @job: The job to be completed.
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* @errp: Error object which may be set by job_complete(); this is not
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* necessarily set on every error, the job return value has to be
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* checked as well.
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*
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* Synchronously complete the job. The completion callback is called before the
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* function returns, unless it is NULL (which is permissible when using this
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* function).
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*
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* Returns the return value from the job.
|
|
*
|
|
* Callers must hold the AioContext lock of job->aio_context.
|
|
*/
|
|
int job_complete_sync(Job *job, Error **errp);
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|
|
|
/**
|
|
* For a @job that has finished its work and is pending awaiting explicit
|
|
* acknowledgement to commit its work, this will commit that work.
|
|
*
|
|
* FIXME: Make the below statement universally true:
|
|
* For jobs that support the manual workflow mode, all graph changes that occur
|
|
* as a result will occur after this command and before a successful reply.
|
|
*/
|
|
void job_finalize(Job *job, Error **errp);
|
|
|
|
/**
|
|
* Remove the concluded @job from the query list and resets the passed pointer
|
|
* to %NULL. Returns an error if the job is not actually concluded.
|
|
*/
|
|
void job_dismiss(Job **job, Error **errp);
|
|
|
|
/**
|
|
* Synchronously finishes the given @job. If @finish is given, it is called to
|
|
* trigger completion or cancellation of the job.
|
|
*
|
|
* Returns 0 if the job is successfully completed, -ECANCELED if the job was
|
|
* cancelled before completing, and -errno in other error cases.
|
|
*
|
|
* Callers must hold the AioContext lock of job->aio_context.
|
|
*/
|
|
int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp);
|
|
|
|
#endif
|