515 lines
15 KiB
C
515 lines
15 KiB
C
/*
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* Declarations for long-running block device operations
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*
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* Copyright (c) 2011 IBM Corp.
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* Copyright (c) 2012 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 BLOCKJOB_H
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#define BLOCKJOB_H
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#include "block/block.h"
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/**
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* BlockJobDriver:
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*
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* A class type for block job driver.
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*/
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typedef struct BlockJobDriver {
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/** Derived BlockJob struct size */
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size_t instance_size;
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/** String describing the operation, part of query-block-jobs QMP API */
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BlockJobType job_type;
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/** Optional callback for job types that support setting a speed limit */
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void (*set_speed)(BlockJob *job, int64_t speed, Error **errp);
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/** Optional callback for job types that need to forward I/O status reset */
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void (*iostatus_reset)(BlockJob *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)(BlockJob *job, Error **errp);
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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)(BlockJob *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)(BlockJob *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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* 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)(BlockJob *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)(BlockJob *job);
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/*
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* If the callback is not NULL, it will be invoked before the job is
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* resumed in a new AioContext. This is the place to move any resources
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* besides job->blk to the new AioContext.
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*/
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void (*attached_aio_context)(BlockJob *job, AioContext *new_context);
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/*
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* If the callback is not NULL, it will be invoked when the job has to be
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* synchronously cancelled or completed; it should drain BlockDriverStates
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* as required to ensure progress.
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*/
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void (*drain)(BlockJob *job);
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} BlockJobDriver;
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/**
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* BlockJob:
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*
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* Long-running operation on a BlockDriverState.
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*/
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struct BlockJob {
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/** The job type, including the job vtable. */
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const BlockJobDriver *driver;
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/** The block device on which the job is operating. */
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BlockBackend *blk;
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/**
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* The ID of the block job.
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*/
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char *id;
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/**
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* The coroutine that executes the job. If not NULL, it is
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* reentered when 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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* 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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* 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 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 false by the job while the coroutine has yielded and may be
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* re-entered by block_job_enter(). There may still be I/O or event loop
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* activity 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 when the job is ready to be completed.
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*/
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bool ready;
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/**
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* Set to true when the job has deferred work to the main loop.
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*/
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bool deferred_to_main_loop;
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/** Element of the list of block jobs */
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QLIST_ENTRY(BlockJob) job_list;
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/** Status that is published by the query-block-jobs QMP API */
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BlockDeviceIoStatus iostatus;
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/** Offset that is published by the query-block-jobs QMP API */
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int64_t offset;
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/** Length that is published by the query-block-jobs QMP API */
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int64_t len;
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/** Speed that was set with @block_job_set_speed. */
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int64_t speed;
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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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/** Block other operations when block job is running */
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Error *blocker;
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/** The opaque value that is passed to the completion function. */
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void *opaque;
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/** Reference count of the block job */
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int refcnt;
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/* True if this job has reported completion by calling block_job_completed.
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*/
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bool completed;
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/* ret code passed to block_job_completed.
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*/
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int ret;
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/** Non-NULL if this job is part of a transaction */
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BlockJobTxn *txn;
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QLIST_ENTRY(BlockJob) txn_list;
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};
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/**
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* block_job_next:
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* @job: A block job, or %NULL.
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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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BlockJob *block_job_next(BlockJob *job);
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/**
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* block_job_get:
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* @id: The id of the block job.
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*
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* Get the block 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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BlockJob *block_job_get(const char *id);
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/**
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* block_job_create:
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* @job_id: The id of the newly-created job, or %NULL to have one
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* generated automatically.
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* @job_type: The class object for the newly-created job.
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* @bs: The block
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* @speed: The maximum speed, in bytes per second, or 0 for unlimited.
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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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* Create a new long-running block device job and return it. The job
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* will call @cb asynchronously when the job completes. Note that
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* @bs may have been closed at the time the @cb it is called. If
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* this is the case, the job may be reported as either cancelled or
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* completed.
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*
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* This function is not part of the public job interface; it should be
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* called from a wrapper that is specific to the job type.
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*/
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void *block_job_create(const char *job_id, const BlockJobDriver *driver,
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BlockDriverState *bs, int64_t speed,
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BlockCompletionFunc *cb, void *opaque, Error **errp);
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/**
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* block_job_sleep_ns:
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* @job: The job that calls the function.
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* @clock: The clock to sleep on.
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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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* nanoseconds. Canceling the job will interrupt the wait immediately.
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*/
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void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns);
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/**
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* block_job_yield:
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* @job: The job that calls the function.
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*
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* Yield the block job coroutine.
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*/
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void block_job_yield(BlockJob *job);
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/**
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* block_job_ref:
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* @bs: The block device.
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*
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* Grab a reference to the block job. Should be paired with block_job_unref.
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*/
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void block_job_ref(BlockJob *job);
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/**
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* block_job_unref:
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* @bs: The block device.
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*
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* Release reference to the block job and release resources if it is the last
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* reference.
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*/
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void block_job_unref(BlockJob *job);
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/**
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* block_job_completed:
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* @job: The job being completed.
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* @ret: The status code.
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*
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* Call the completion function that was registered at creation time, and
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* free @job.
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*/
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void block_job_completed(BlockJob *job, int ret);
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/**
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* block_job_set_speed:
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* @job: The job to set the speed for.
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* @speed: The new value
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* @errp: Error object.
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*
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* Set a rate-limiting parameter for the job; the actual meaning may
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* vary depending on the job type.
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*/
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void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp);
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/**
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* block_job_cancel:
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* @job: The job to be canceled.
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*
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* Asynchronously cancel the specified job.
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*/
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void block_job_cancel(BlockJob *job);
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/**
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* block_job_complete:
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* @job: The job to be completed.
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* @errp: Error object.
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*
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* Asynchronously complete the specified job.
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*/
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void block_job_complete(BlockJob *job, Error **errp);
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/**
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* block_job_is_cancelled:
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* @job: The job being queried.
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*
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* Returns whether the job is scheduled for cancellation.
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*/
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bool block_job_is_cancelled(BlockJob *job);
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/**
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* block_job_query:
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* @job: The job to get information about.
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*
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* Return information about a job.
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*/
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BlockJobInfo *block_job_query(BlockJob *job);
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/**
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* block_job_pause_point:
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* @job: The job that is ready to pause.
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*
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* Pause now if block_job_pause() has been called. Block jobs that perform
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* lots of I/O must call this between requests so that the job can be paused.
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*/
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void coroutine_fn block_job_pause_point(BlockJob *job);
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/**
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* block_job_pause:
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* @job: The job to be paused.
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*
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* Asynchronously pause the specified job.
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*/
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void block_job_pause(BlockJob *job);
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/**
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* block_job_resume:
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* @job: The job to be resumed.
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*
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* Resume the specified job. Must be paired with a preceding block_job_pause.
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*/
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void block_job_resume(BlockJob *job);
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/**
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* block_job_enter:
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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 block_job_enter(BlockJob *job);
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/**
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* block_job_event_cancelled:
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* @job: The job whose information is requested.
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*
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* Send a BLOCK_JOB_CANCELLED event for the specified job.
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*/
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void block_job_event_cancelled(BlockJob *job);
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/**
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* block_job_ready:
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* @job: The job which is now ready to complete.
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* @msg: Error message. Only present on failure.
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*
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* Send a BLOCK_JOB_COMPLETED event for the specified job.
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*/
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void block_job_event_completed(BlockJob *job, const char *msg);
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/**
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* block_job_ready:
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* @job: The job which is now ready to complete.
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*
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* Send a BLOCK_JOB_READY event for the specified job.
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*/
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void block_job_event_ready(BlockJob *job);
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/**
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* block_job_cancel_sync:
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* @job: The job to be canceled.
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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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int block_job_cancel_sync(BlockJob *job);
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/**
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* block_job_cancel_sync_all:
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*
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* Synchronously cancels all jobs using block_job_cancel_sync().
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*/
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void block_job_cancel_sync_all(void);
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/**
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* block_job_complete_sync:
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* @job: The job to be completed.
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* @errp: Error object which may be set by block_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.
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*/
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int block_job_complete_sync(BlockJob *job, Error **errp);
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/**
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* block_job_iostatus_reset:
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* @job: The job whose I/O status should be reset.
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*
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* Reset I/O status on @job and on BlockDriverState objects it uses,
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* other than job->blk.
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*/
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void block_job_iostatus_reset(BlockJob *job);
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/**
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* block_job_error_action:
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* @job: The job to signal an error for.
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* @on_err: The error action setting.
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* @is_read: Whether the operation was a read.
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* @error: The error that was reported.
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*
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* Report an I/O error for a block job and possibly stop the VM. Return the
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* action that was selected based on @on_err and @error.
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*/
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BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
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int is_read, int error);
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typedef void BlockJobDeferToMainLoopFn(BlockJob *job, void *opaque);
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/**
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* block_job_defer_to_main_loop:
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* @job: The job
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* @fn: The function to run in the main loop
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* @opaque: The opaque value that is passed to @fn
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*
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* Execute a given function in the main loop with the BlockDriverState
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* AioContext acquired. Block jobs must call bdrv_unref(), bdrv_close(), and
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* anything that uses bdrv_drain_all() in the main loop.
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*
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* The @job AioContext is held while @fn executes.
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*/
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void block_job_defer_to_main_loop(BlockJob *job,
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BlockJobDeferToMainLoopFn *fn,
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void *opaque);
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/**
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* block_job_txn_new:
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*
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* Allocate and return a new block job transaction. Jobs can be added to the
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* transaction using block_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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BlockJobTxn *block_job_txn_new(void);
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/**
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* block_job_txn_unref:
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*
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* Release a reference that was previously acquired with block_job_txn_add_job
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* or block_job_txn_new. If it's the last reference to the object, it will be
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* freed.
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*/
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void block_job_txn_unref(BlockJobTxn *txn);
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/**
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* block_job_txn_add_job:
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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 block_job_txn_unref() or block_job_completed()
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* to release the reference that is automatically grabbed here.
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*/
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void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job);
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#endif
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