qemu-e2k/include/qemu/job.h

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/*
* Declarations for background jobs
*
* Copyright (c) 2011 IBM Corp.
* Copyright (c) 2012, 2018 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 JOB_H
#define JOB_H
Include generated QAPI headers less Some of the generated qapi-types-MODULE.h are included all over the place. Changing a QAPI type can trigger massive recompiling. Top scorers recompile more than 1000 out of some 6600 objects (not counting tests and objects that don't depend on qemu/osdep.h): 6300 qapi/qapi-builtin-types.h 5700 qapi/qapi-types-run-state.h 3900 qapi/qapi-types-common.h 3300 qapi/qapi-types-sockets.h 3000 qapi/qapi-types-misc.h 3000 qapi/qapi-types-crypto.h 3000 qapi/qapi-types-job.h 3000 qapi/qapi-types-block-core.h 2800 qapi/qapi-types-block.h 1300 qapi/qapi-types-net.h Clean up headers to include generated QAPI headers only where needed. Impact is negligible except for hw/qdev-properties.h. This header includes qapi/qapi-types-block.h and qapi/qapi-types-misc.h. They are used only in expansions of property definition macros such as DEFINE_PROP_BLOCKDEV_ON_ERROR() and DEFINE_PROP_OFF_AUTO(). Moving their inclusion from hw/qdev-properties.h to the users of these macros avoids pointless recompiles. This is how other property definition macros, such as DEFINE_PROP_NETDEV(), already work. Improves things for some of the top scorers: 3600 qapi/qapi-types-common.h 2800 qapi/qapi-types-sockets.h 900 qapi/qapi-types-misc.h 2200 qapi/qapi-types-crypto.h 2100 qapi/qapi-types-job.h 2100 qapi/qapi-types-block-core.h 270 qapi/qapi-types-block.h Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <20190812052359.30071-3-armbru@redhat.com>
2019-08-12 07:23:32 +02:00
#include "qapi/qapi-types-job.h"
#include "qemu/queue.h"
#include "qemu/progress_meter.h"
#include "qemu/coroutine.h"
#include "block/aio.h"
typedef struct JobDriver JobDriver;
typedef struct JobTxn JobTxn;
/**
* Long-running operation.
*/
typedef struct Job {
/** The ID of the job. May be NULL for internal jobs. */
char *id;
/** The type of this job. */
const JobDriver *driver;
/** Reference count of the block job */
int refcnt;
/** Current state; See @JobStatus for details. */
JobStatus status;
/** AioContext to run the job coroutine in */
AioContext *aio_context;
/**
* The coroutine that executes the job. If not NULL, it is reentered when
* busy is false and the job is cancelled.
*/
Coroutine *co;
/**
* Timer that is used by @job_sleep_ns. Accessed under job_mutex (in
* job.c).
*/
QEMUTimer sleep_timer;
/**
* 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 false by the job while the coroutine has yielded and may be
* re-entered by job_enter(). There may still be I/O or event loop activity
* pending. Accessed under block_job_mutex (in blockjob.c).
*
* When the job is deferred to the main loop, busy is true as long as the
* bottom half is still pending.
*/
bool busy;
/**
* Set to true by the job while it is in a quiescent state, where
* no I/O or event loop activity is pending.
*/
bool paused;
/**
* 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 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;
/**
* Set to true if the job should abort immediately without waiting
* for data to be in sync.
*/
bool force_cancel;
/** Set to true when the job has deferred work to the main loop. */
bool deferred_to_main_loop;
/** True if this job should automatically finalize itself */
bool auto_finalize;
/** True if this job should automatically dismiss itself */
bool auto_dismiss;
ProgressMeter progress;
/**
* Return code from @run and/or @prepare callback(s).
* Not final until the job has reached the CONCLUDED status.
* 0 on success, -errno on failure.
*/
int ret;
/**
* Error object for a failed job.
* If job->ret is nonzero and an error object was not set, it will be set
* to strerror(-job->ret) during job_completed.
*/
Error *err;
/** The completion function that will be called when the job completes. */
BlockCompletionFunc *cb;
/** The opaque value that is passed to the completion function. */
void *opaque;
/** Notifiers called when a cancelled job is finalised */
NotifierList on_finalize_cancelled;
/** Notifiers called when a successfully completed job is finalised */
NotifierList on_finalize_completed;
/** Notifiers called when the job transitions to PENDING */
NotifierList on_pending;
/** Notifiers called when the job transitions to READY */
NotifierList on_ready;
/** Notifiers called when the job coroutine yields or terminates */
NotifierList on_idle;
/** Element of the list of jobs */
QLIST_ENTRY(Job) job_list;
/** Transaction this job is part of */
JobTxn *txn;
/** Element of the list of jobs in a job transaction */
QLIST_ENTRY(Job) txn_list;
} Job;
/**
* Callbacks and other information about a Job driver.
*/
struct JobDriver {
/** Derived Job struct size */
size_t instance_size;
/** Enum describing the operation */
JobType job_type;
/**
* Mandatory: Entrypoint for the Coroutine.
*
* This callback will be invoked when moving from CREATED to RUNNING.
*
* If this callback returns nonzero, the job transaction it is part of is
* aborted. If it returns zero, the job moves into the WAITING state. If it
* is the last job to complete in its transaction, all jobs in the
* transaction move from WAITING to PENDING.
*/
int coroutine_fn (*run)(Job *job, Error **errp);
/**
* If the callback is not NULL, it will be invoked when the job transitions
* into the paused state. Paused jobs must not perform any asynchronous
* I/O or event loop activity. This callback is used to quiesce jobs.
*/
void coroutine_fn (*pause)(Job *job);
/**
* If the callback is not NULL, it will be invoked when the job transitions
* out of the paused state. Any asynchronous I/O or event loop activity
* should be restarted from this callback.
*/
void coroutine_fn (*resume)(Job *job);
/**
* Called when the job is resumed by the user (i.e. user_paused becomes
* false). .user_resume is called before .resume.
*/
void (*user_resume)(Job *job);
/**
* Optional callback for job types whose completion must be triggered
* manually.
*/
void (*complete)(Job *job, Error **errp);
/**
* If the callback is not NULL, prepare 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.
*
* This callback will not be invoked if the job has already failed.
* If it fails, abort and then clean will be called.
*/
int (*prepare)(Job *job);
/**
* 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)(Job *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)(Job *job);
/**
* If the callback is not NULL, it will be invoked after a call to either
* .commit() or .abort(). Regardless of which callback is invoked after
* completion, .clean() will always be called, even if the job does not
* belong to a transaction group.
*/
void (*clean)(Job *job);
/**
* If the callback is not NULL, it will be invoked in job_cancel_async
jobs: Give Job.force_cancel more meaning We largely have two cancel modes for jobs: First, there is actual cancelling. The job is terminated as soon as possible, without trying to reach a consistent result. Second, we have mirror in the READY state. Technically, the job is not really cancelled, but it just is a different completion mode. The job can still run for an indefinite amount of time while it tries to reach a consistent result. We want to be able to clearly distinguish which cancel mode a job is in (when it has been cancelled). We can use Job.force_cancel for this, but right now it only reflects cancel requests from the user with force=true, but clearly, jobs that do not even distinguish between force=false and force=true are effectively always force-cancelled. So this patch has Job.force_cancel signify whether the job will terminate as soon as possible (force_cancel=true) or whether it will effectively remain running despite being "cancelled" (force_cancel=false). To this end, we let jobs that provide JobDriver.cancel() tell the generic job code whether they will terminate as soon as possible or not, and for jobs that do not provide that method we assume they will. Signed-off-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20211006151940.214590-7-hreitz@redhat.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2021-10-06 17:19:33 +02:00
*
* This function must return true if the job will be cancelled
* immediately without any further I/O (mandatory if @force is
* true), and false otherwise. This lets the generic job layer
* know whether a job has been truly (force-)cancelled, or whether
* it is just in a special completion mode (like mirror after
* READY).
* (If the callback is NULL, the job is assumed to terminate
* without I/O.)
*/
jobs: Give Job.force_cancel more meaning We largely have two cancel modes for jobs: First, there is actual cancelling. The job is terminated as soon as possible, without trying to reach a consistent result. Second, we have mirror in the READY state. Technically, the job is not really cancelled, but it just is a different completion mode. The job can still run for an indefinite amount of time while it tries to reach a consistent result. We want to be able to clearly distinguish which cancel mode a job is in (when it has been cancelled). We can use Job.force_cancel for this, but right now it only reflects cancel requests from the user with force=true, but clearly, jobs that do not even distinguish between force=false and force=true are effectively always force-cancelled. So this patch has Job.force_cancel signify whether the job will terminate as soon as possible (force_cancel=true) or whether it will effectively remain running despite being "cancelled" (force_cancel=false). To this end, we let jobs that provide JobDriver.cancel() tell the generic job code whether they will terminate as soon as possible or not, and for jobs that do not provide that method we assume they will. Signed-off-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20211006151940.214590-7-hreitz@redhat.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2021-10-06 17:19:33 +02:00
bool (*cancel)(Job *job, bool force);
/** Called when the job is freed */
void (*free)(Job *job);
};
typedef enum JobCreateFlags {
/* Default behavior */
JOB_DEFAULT = 0x00,
/* Job is not QMP-created and should not send QMP events */
JOB_INTERNAL = 0x01,
/* Job requires manual finalize step */
JOB_MANUAL_FINALIZE = 0x02,
/* Job requires manual dismiss step */
JOB_MANUAL_DISMISS = 0x04,
} JobCreateFlags;
/**
* Allocate and return a new job transaction. Jobs can be added to the
* transaction using 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.
*/
JobTxn *job_txn_new(void);
/**
* Release a reference that was previously acquired with job_txn_add_job or
* job_txn_new. If it's the last reference to the object, it will be freed.
*/
void job_txn_unref(JobTxn *txn);
/**
* @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 job_txn_unref() or job_completed() to release
* the reference that is automatically grabbed here.
*
* If @txn is NULL, the function does nothing.
*/
void job_txn_add_job(JobTxn *txn, Job *job);
/**
* Create a new long-running job and return it.
*
* @job_id: The id of the newly-created job, or %NULL for internal jobs
* @driver: The class object for the newly-created job.
* @txn: The transaction this job belongs to, if any. %NULL otherwise.
* @ctx: The AioContext to run the job coroutine in.
* @flags: Creation flags for the job. See @JobCreateFlags.
* @cb: Completion function for the job.
* @opaque: Opaque pointer value passed to @cb.
* @errp: Error object.
*/
void *job_create(const char *job_id, const JobDriver *driver, JobTxn *txn,
AioContext *ctx, int flags, BlockCompletionFunc *cb,
void *opaque, Error **errp);
/**
* Add a reference to Job refcnt, it will be decreased with job_unref, and then
* be freed if it comes to be the last reference.
*/
void job_ref(Job *job);
/**
* Release a reference that was previously acquired with job_ref() or
* job_create(). If it's the last reference to the object, it will be freed.
*/
void job_unref(Job *job);
/**
* @job: The job that has made progress
* @done: How much progress the job made since the last call
*
* Updates the progress counter of the job.
*/
void job_progress_update(Job *job, uint64_t done);
/**
* @job: The job whose expected progress end value is set
* @remaining: Missing progress (on top of the current progress counter value)
* until the new expected end value is reached
*
* Sets the expected end value of the progress counter of a job so that a
* completion percentage can be calculated when the progress is updated.
*/
void job_progress_set_remaining(Job *job, uint64_t remaining);
/**
* @job: The job whose expected progress end value is updated
* @delta: Value which is to be added to the current expected end
* value
*
* Increases the expected end value of the progress counter of a job.
* This is useful for parenthesis operations: If a job has to
* conditionally perform a high-priority operation as part of its
* progress, it calls this function with the expected operation's
* length before, and job_progress_update() afterwards.
* (So the operation acts as a parenthesis in regards to the main job
* operation running in background.)
*/
void job_progress_increase_remaining(Job *job, uint64_t delta);
/** To be called when a cancelled job is finalised. */
void job_event_cancelled(Job *job);
/** To be called when a successfully completed job is finalised. */
void job_event_completed(Job *job);
/**
* Conditionally enter the job coroutine if the job is ready to run, not
* already busy and fn() returns true. fn() is called while under the job_lock
* critical section.
*/
void job_enter_cond(Job *job, bool(*fn)(Job *job));
/**
* @job: A job that has not yet been started.
*
* Begins execution of a job.
* Takes ownership of one reference to the job object.
*/
void job_start(Job *job);
/**
* @job: The job to enter.
*
* Continue the specified job by entering the coroutine.
*/
void job_enter(Job *job);
/**
* @job: The job that is ready to pause.
*
* Pause now if job_pause() has been called. Jobs that perform lots of I/O
* must call this between requests so that the job can be paused.
*/
void coroutine_fn job_pause_point(Job *job);
/**
* @job: The job that calls the function.
*
* Yield the job coroutine.
*/
void job_yield(Job *job);
/**
* @job: The job that calls the function.
* @ns: How many nanoseconds to stop for.
*
* Put the job to sleep (assuming that it wasn't canceled) for @ns
* %QEMU_CLOCK_REALTIME nanoseconds. Canceling the job will immediately
* interrupt the wait.
*/
void coroutine_fn job_sleep_ns(Job *job, int64_t ns);
/** Returns the JobType of a given Job. */
JobType job_type(const Job *job);
/** Returns the enum string for the JobType of a given Job. */
const char *job_type_str(const Job *job);
/** Returns true if the job should not be visible to the management layer. */
bool job_is_internal(Job *job);
job: Add job_cancel_requested() Most callers of job_is_cancelled() actually want to know whether the job is on its way to immediate termination. For example, we refuse to pause jobs that are cancelled; but this only makes sense for jobs that are really actually cancelled. A mirror job that is cancelled during READY with force=false should absolutely be allowed to pause. This "cancellation" (which is actually a kind of completion) may take an indefinite amount of time, and so should behave like any job during normal operation. For example, with on-target-error=stop, the job should stop on write errors. (In contrast, force-cancelled jobs should not get write errors, as they should just terminate and not do further I/O.) Therefore, redefine job_is_cancelled() to only return true for jobs that are force-cancelled (which as of HEAD^ means any job that interprets the cancellation request as a request for immediate termination), and add job_cancel_requested() as the general variant, which returns true for any jobs which have been requested to be cancelled, whether it be immediately or after an arbitrarily long completion phase. Finally, here is a justification for how different job_is_cancelled() invocations are treated by this patch: - block/mirror.c (mirror_run()): - The first invocation is a while loop that should loop until the job has been cancelled or scheduled for completion. What kind of cancel does not matter, only the fact that the job is supposed to end. - The second invocation wants to know whether the job has been soft-cancelled. Calling job_cancel_requested() is a bit too broad, but if the job were force-cancelled, we should leave the main loop as soon as possible anyway, so this should not matter here. - The last two invocations already check force_cancel, so they should continue to use job_is_cancelled(). - block/backup.c, block/commit.c, block/stream.c, anything in tests/: These jobs know only force-cancel, so there is no difference between job_is_cancelled() and job_cancel_requested(). We can continue using job_is_cancelled(). - job.c: - job_pause_point(), job_yield(), job_sleep_ns(): Only force-cancelled jobs should be prevented from being paused. Continue using job_is_cancelled(). - job_update_rc(), job_finalize_single(), job_finish_sync(): These functions are all called after the job has left its main loop. The mirror job (the only job that can be soft-cancelled) will clear .cancelled before leaving the main loop if it has been soft-cancelled. Therefore, these functions will observe .cancelled to be true only if the job has been force-cancelled. We can continue to use job_is_cancelled(). (Furthermore, conceptually, a soft-cancelled mirror job should not report to have been cancelled. It should report completion (see also the block-job-cancel QAPI documentation). Therefore, it makes sense for these functions not to distinguish between a soft-cancelled mirror job and a job that has completed as normal.) - job_completed_txn_abort(): All jobs other than @job have been force-cancelled. job_is_cancelled() must be true for them. Regarding @job itself: job_completed_txn_abort() is mostly called when the job's return value is not 0. A soft-cancelled mirror has a return value of 0, and so will not end up here then. However, job_cancel() invokes job_completed_txn_abort() if the job has been deferred to the main loop, which is mostly the case for completed jobs (which skip the assertion), but not for sure. To be safe, use job_cancel_requested() in this assertion. - job_complete(): This is function eventually invoked by the user (through qmp_block_job_complete() or qmp_job_complete(), or job_complete_sync(), which comes from qemu-img). The intention here is to prevent a user from invoking job-complete after the job has been cancelled. This should also apply to soft cancelling: After a mirror job has been soft-cancelled, the user should not be able to decide otherwise and have it complete as normal (i.e. pivoting to the target). - job_cancel(): Both functions are equivalent (see comment there), but we want to use job_is_cancelled(), because this shows that we call job_completed_txn_abort() only for force-cancelled jobs. (As explained for job_update_rc(), soft-cancelled jobs should be treated as if they have completed as normal.) Buglink: https://gitlab.com/qemu-project/qemu/-/issues/462 Signed-off-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20211006151940.214590-9-hreitz@redhat.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2021-10-06 17:19:35 +02:00
/** Returns whether the job is being cancelled. */
bool job_is_cancelled(Job *job);
job: Add job_cancel_requested() Most callers of job_is_cancelled() actually want to know whether the job is on its way to immediate termination. For example, we refuse to pause jobs that are cancelled; but this only makes sense for jobs that are really actually cancelled. A mirror job that is cancelled during READY with force=false should absolutely be allowed to pause. This "cancellation" (which is actually a kind of completion) may take an indefinite amount of time, and so should behave like any job during normal operation. For example, with on-target-error=stop, the job should stop on write errors. (In contrast, force-cancelled jobs should not get write errors, as they should just terminate and not do further I/O.) Therefore, redefine job_is_cancelled() to only return true for jobs that are force-cancelled (which as of HEAD^ means any job that interprets the cancellation request as a request for immediate termination), and add job_cancel_requested() as the general variant, which returns true for any jobs which have been requested to be cancelled, whether it be immediately or after an arbitrarily long completion phase. Finally, here is a justification for how different job_is_cancelled() invocations are treated by this patch: - block/mirror.c (mirror_run()): - The first invocation is a while loop that should loop until the job has been cancelled or scheduled for completion. What kind of cancel does not matter, only the fact that the job is supposed to end. - The second invocation wants to know whether the job has been soft-cancelled. Calling job_cancel_requested() is a bit too broad, but if the job were force-cancelled, we should leave the main loop as soon as possible anyway, so this should not matter here. - The last two invocations already check force_cancel, so they should continue to use job_is_cancelled(). - block/backup.c, block/commit.c, block/stream.c, anything in tests/: These jobs know only force-cancel, so there is no difference between job_is_cancelled() and job_cancel_requested(). We can continue using job_is_cancelled(). - job.c: - job_pause_point(), job_yield(), job_sleep_ns(): Only force-cancelled jobs should be prevented from being paused. Continue using job_is_cancelled(). - job_update_rc(), job_finalize_single(), job_finish_sync(): These functions are all called after the job has left its main loop. The mirror job (the only job that can be soft-cancelled) will clear .cancelled before leaving the main loop if it has been soft-cancelled. Therefore, these functions will observe .cancelled to be true only if the job has been force-cancelled. We can continue to use job_is_cancelled(). (Furthermore, conceptually, a soft-cancelled mirror job should not report to have been cancelled. It should report completion (see also the block-job-cancel QAPI documentation). Therefore, it makes sense for these functions not to distinguish between a soft-cancelled mirror job and a job that has completed as normal.) - job_completed_txn_abort(): All jobs other than @job have been force-cancelled. job_is_cancelled() must be true for them. Regarding @job itself: job_completed_txn_abort() is mostly called when the job's return value is not 0. A soft-cancelled mirror has a return value of 0, and so will not end up here then. However, job_cancel() invokes job_completed_txn_abort() if the job has been deferred to the main loop, which is mostly the case for completed jobs (which skip the assertion), but not for sure. To be safe, use job_cancel_requested() in this assertion. - job_complete(): This is function eventually invoked by the user (through qmp_block_job_complete() or qmp_job_complete(), or job_complete_sync(), which comes from qemu-img). The intention here is to prevent a user from invoking job-complete after the job has been cancelled. This should also apply to soft cancelling: After a mirror job has been soft-cancelled, the user should not be able to decide otherwise and have it complete as normal (i.e. pivoting to the target). - job_cancel(): Both functions are equivalent (see comment there), but we want to use job_is_cancelled(), because this shows that we call job_completed_txn_abort() only for force-cancelled jobs. (As explained for job_update_rc(), soft-cancelled jobs should be treated as if they have completed as normal.) Buglink: https://gitlab.com/qemu-project/qemu/-/issues/462 Signed-off-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20211006151940.214590-9-hreitz@redhat.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2021-10-06 17:19:35 +02:00
/**
* Returns whether the job is scheduled for cancellation (at an
* indefinite point).
*/
bool job_cancel_requested(Job *job);
/** Returns whether the job is in a completed state. */
bool job_is_completed(Job *job);
/** Returns whether the job is ready to be completed. */
bool job_is_ready(Job *job);
/**
* Request @job to pause at the next pause point. Must be paired with
* job_resume(). If the job is supposed to be resumed by user action, call
* job_user_pause() instead.
*/
void job_pause(Job *job);
/** Resumes a @job paused with job_pause. */
void job_resume(Job *job);
/**
* Asynchronously pause the specified @job.
* Do not allow a resume until a matching call to job_user_resume.
*/
void job_user_pause(Job *job, Error **errp);
/** Returns true if the job is user-paused. */
bool job_user_paused(Job *job);
/**
* Resume the specified @job.
* Must be paired with a preceding job_user_pause.
*/
void job_user_resume(Job *job, Error **errp);
/**
* Get the next element from the list of block jobs after @job, or the
* first one if @job is %NULL.
*
* Returns the requested job, or %NULL if there are no more jobs left.
*/
Job *job_next(Job *job);
/**
* Get the job identified by @id (which must not be %NULL).
*
* Returns the requested job, or %NULL if it doesn't exist.
*/
Job *job_get(const char *id);
/**
* Check whether the verb @verb can be applied to @job in its current state.
* Returns 0 if the verb can be applied; otherwise errp is set and -EPERM
* returned.
*/
int job_apply_verb(Job *job, JobVerb verb, Error **errp);
/** The @job could not be started, free it. */
void job_early_fail(Job *job);
/** Moves the @job from RUNNING to READY */
void job_transition_to_ready(Job *job);
/** Asynchronously complete the specified @job. */
void job_complete(Job *job, Error **errp);
/**
* Asynchronously cancel the specified @job. If @force is true, the job should
* be cancelled immediately without waiting for a consistent state.
*/
void job_cancel(Job *job, bool force);
/**
* Cancels the specified job like job_cancel(), but may refuse to do so if the
* operation isn't meaningful in the current state of the job.
*/
void job_user_cancel(Job *job, bool force, Error **errp);
/**
* Synchronously cancel the @job. The completion callback is called
* before the function returns. If @force is false, 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.
*
* Callers must hold the AioContext lock of job->aio_context.
*/
int job_cancel_sync(Job *job, bool force);
/** Synchronously force-cancels all jobs using job_cancel_sync(). */
void job_cancel_sync_all(void);
/**
* @job: The job to be completed.
* @errp: Error object which may be set by 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.
*
* Callers must hold the AioContext lock of job->aio_context.
*/
int job_complete_sync(Job *job, Error **errp);
/**
* 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