diff options
Diffstat (limited to 'src/include/block/blockjob.h')
| -rw-r--r-- | src/include/block/blockjob.h | 446 |
1 files changed, 446 insertions, 0 deletions
diff --git a/src/include/block/blockjob.h b/src/include/block/blockjob.h new file mode 100644 index 0000000..d84ccd8 --- /dev/null +++ b/src/include/block/blockjob.h @@ -0,0 +1,446 @@ +/* + * Declarations for long-running block device operations + * + * Copyright (c) 2011 IBM Corp. + * Copyright (c) 2012 Red Hat, Inc. + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ +#ifndef BLOCKJOB_H +#define BLOCKJOB_H 1 + +#include "block/block.h" + +/** + * BlockJobDriver: + * + * A class type for block job driver. + */ +typedef struct BlockJobDriver { + /** Derived BlockJob struct size */ + size_t instance_size; + + /** String describing the operation, part of query-block-jobs QMP API */ + BlockJobType job_type; + + /** Optional callback for job types that support setting a speed limit */ + void (*set_speed)(BlockJob *job, int64_t speed, Error **errp); + + /** Optional callback for job types that need to forward I/O status reset */ + void (*iostatus_reset)(BlockJob *job); + + /** + * Optional callback for job types whose completion must be triggered + * manually. + */ + void (*complete)(BlockJob *job, Error **errp); + + /** + * If the callback is not NULL, it will be invoked when all the jobs + * belonging to the same transaction complete; or upon this job's + * completion if it is not in a transaction. Skipped if NULL. + * + * All jobs will complete with a call to either .commit() or .abort() but + * never both. + */ + void (*commit)(BlockJob *job); + + /** + * If the callback is not NULL, it will be invoked when any job in the + * same transaction fails; or upon this job's failure (due to error or + * cancellation) if it is not in a transaction. Skipped if NULL. + * + * All jobs will complete with a call to either .commit() or .abort() but + * never both. + */ + void (*abort)(BlockJob *job); +} BlockJobDriver; + +/** + * BlockJob: + * + * Long-running operation on a BlockDriverState. + */ +struct BlockJob { + /** The job type, including the job vtable. */ + const BlockJobDriver *driver; + + /** The block device on which the job is operating. */ + BlockDriverState *bs; + + /** + * The ID of the block job. Currently the BlockBackend name of the BDS + * owning the job at the time when the job is started. + * + * TODO Decouple block job IDs from BlockBackend names + */ + char *id; + + /** + * The coroutine that executes the job. If not NULL, it is + * reentered when busy is false and the job is cancelled. + */ + Coroutine *co; + + /** + * Set to true if the job should cancel itself. The flag must + * always be tested just before toggling the busy flag from false + * to true. After a job has been cancelled, it should only yield + * if #aio_poll will ("sooner or later") reenter the coroutine. + */ + bool cancelled; + + /** + * Counter for pause request. If non-zero, the block job is either paused, + * or if busy == true will pause itself as soon as possible. + */ + int pause_count; + + /** + * Set to true if the job is paused by user. Can be unpaused with the + * block-job-resume QMP command. + */ + bool user_paused; + + /** + * Set to false by the job while it is in a quiescent state, where + * no I/O is pending and the job has yielded on any condition + * that is not detected by #aio_poll, such as a timer. + */ + bool busy; + + /** + * Set to true when the job is ready to be completed. + */ + bool ready; + + /** Status that is published by the query-block-jobs QMP API */ + BlockDeviceIoStatus iostatus; + + /** Offset that is published by the query-block-jobs QMP API */ + int64_t offset; + + /** Length that is published by the query-block-jobs QMP API */ + int64_t len; + + /** Speed that was set with @block_job_set_speed. */ + int64_t speed; + + /** The completion function that will be called when the job completes. */ + BlockCompletionFunc *cb; + + /** Block other operations when block job is running */ + Error *blocker; + + /** The opaque value that is passed to the completion function. */ + void *opaque; + + /** Reference count of the block job */ + int refcnt; + + /* True if this job has reported completion by calling block_job_completed. + */ + bool completed; + + /* ret code passed to block_job_completed. + */ + int ret; + + /** Non-NULL if this job is part of a transaction */ + BlockJobTxn *txn; + QLIST_ENTRY(BlockJob) txn_list; +}; + +/** + * block_job_create: + * @job_type: The class object for the newly-created job. + * @bs: The block + * @speed: The maximum speed, in bytes per second, or 0 for unlimited. + * @cb: Completion function for the job. + * @opaque: Opaque pointer value passed to @cb. + * @errp: Error object. + * + * Create a new long-running block device job and return it. The job + * will call @cb asynchronously when the job completes. Note that + * @bs may have been closed at the time the @cb it is called. If + * this is the case, the job may be reported as either cancelled or + * completed. + * + * This function is not part of the public job interface; it should be + * called from a wrapper that is specific to the job type. + */ +void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs, + int64_t speed, BlockCompletionFunc *cb, + void *opaque, Error **errp); + +/** + * block_job_sleep_ns: + * @job: The job that calls the function. + * @clock: The clock to sleep on. + * @ns: How many nanoseconds to stop for. + * + * Put the job to sleep (assuming that it wasn't canceled) for @ns + * nanoseconds. Canceling the job will interrupt the wait immediately. + */ +void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns); + +/** + * block_job_yield: + * @job: The job that calls the function. + * + * Yield the block job coroutine. + */ +void block_job_yield(BlockJob *job); + +/** + * block_job_ref: + * @bs: The block device. + * + * Grab a reference to the block job. Should be paired with block_job_unref. + */ +void block_job_ref(BlockJob *job); + +/** + * block_job_unref: + * @bs: The block device. + * + * Release reference to the block job and release resources if it is the last + * reference. + */ +void block_job_unref(BlockJob *job); + +/** + * block_job_completed: + * @job: The job being completed. + * @ret: The status code. + * + * Call the completion function that was registered at creation time, and + * free @job. + */ +void block_job_completed(BlockJob *job, int ret); + +/** + * block_job_set_speed: + * @job: The job to set the speed for. + * @speed: The new value + * @errp: Error object. + * + * Set a rate-limiting parameter for the job; the actual meaning may + * vary depending on the job type. + */ +void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp); + +/** + * block_job_cancel: + * @job: The job to be canceled. + * + * Asynchronously cancel the specified job. + */ +void block_job_cancel(BlockJob *job); + +/** + * block_job_complete: + * @job: The job to be completed. + * @errp: Error object. + * + * Asynchronously complete the specified job. + */ +void block_job_complete(BlockJob *job, Error **errp); + +/** + * block_job_is_cancelled: + * @job: The job being queried. + * + * Returns whether the job is scheduled for cancellation. + */ +bool block_job_is_cancelled(BlockJob *job); + +/** + * block_job_query: + * @job: The job to get information about. + * + * Return information about a job. + */ +BlockJobInfo *block_job_query(BlockJob *job); + +/** + * block_job_pause: + * @job: The job to be paused. + * + * Asynchronously pause the specified job. + */ +void block_job_pause(BlockJob *job); + +/** + * block_job_resume: + * @job: The job to be resumed. + * + * Resume the specified job. Must be paired with a preceding block_job_pause. + */ +void block_job_resume(BlockJob *job); + +/** + * block_job_enter: + * @job: The job to enter. + * + * Continue the specified job by entering the coroutine. + */ +void block_job_enter(BlockJob *job); + +/** + * block_job_event_cancelled: + * @job: The job whose information is requested. + * + * Send a BLOCK_JOB_CANCELLED event for the specified job. + */ +void block_job_event_cancelled(BlockJob *job); + +/** + * block_job_ready: + * @job: The job which is now ready to complete. + * @msg: Error message. Only present on failure. + * + * Send a BLOCK_JOB_COMPLETED event for the specified job. + */ +void block_job_event_completed(BlockJob *job, const char *msg); + +/** + * block_job_ready: + * @job: The job which is now ready to complete. + * + * Send a BLOCK_JOB_READY event for the specified job. + */ +void block_job_event_ready(BlockJob *job); + +/** + * block_job_is_paused: + * @job: The job being queried. + * + * Returns whether the job is currently paused, or will pause + * as soon as it reaches a sleeping point. + */ +bool block_job_is_paused(BlockJob *job); + +/** + * block_job_cancel_sync: + * @job: The job to be canceled. + * + * Synchronously cancel the job. The completion callback is called + * before the function returns. The job may actually complete + * instead of canceling itself; the circumstances under which this + * happens depend on the kind of job that is active. + * + * Returns the return value from the job if the job actually completed + * during the call, or -ECANCELED if it was canceled. + */ +int block_job_cancel_sync(BlockJob *job); + +/** + * block_job_complete_sync: + * @job: The job to be completed. + * @errp: Error object which may be set by block_job_complete(); this is not + * necessarily set on every error, the job return value has to be + * checked as well. + * + * Synchronously complete the job. The completion callback is called before the + * function returns, unless it is NULL (which is permissible when using this + * function). + * + * Returns the return value from the job. + */ +int block_job_complete_sync(BlockJob *job, Error **errp); + +/** + * block_job_iostatus_reset: + * @job: The job whose I/O status should be reset. + * + * Reset I/O status on @job and on BlockDriverState objects it uses, + * other than job->bs. + */ +void block_job_iostatus_reset(BlockJob *job); + +/** + * block_job_error_action: + * @job: The job to signal an error for. + * @bs: The block device on which to set an I/O error. + * @on_err: The error action setting. + * @is_read: Whether the operation was a read. + * @error: The error that was reported. + * + * Report an I/O error for a block job and possibly stop the VM. Return the + * action that was selected based on @on_err and @error. + */ +BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs, + BlockdevOnError on_err, + int is_read, int error); + +typedef void BlockJobDeferToMainLoopFn(BlockJob *job, void *opaque); + +/** + * block_job_defer_to_main_loop: + * @job: The job + * @fn: The function to run in the main loop + * @opaque: The opaque value that is passed to @fn + * + * Execute a given function in the main loop with the BlockDriverState + * AioContext acquired. Block jobs must call bdrv_unref(), bdrv_close(), and + * anything that uses bdrv_drain_all() in the main loop. + * + * The @job AioContext is held while @fn executes. + */ +void block_job_defer_to_main_loop(BlockJob *job, + BlockJobDeferToMainLoopFn *fn, + void *opaque); + +/** + * block_job_txn_new: + * + * Allocate and return a new block job transaction. Jobs can be added to the + * transaction using block_job_txn_add_job(). + * + * The transaction is automatically freed when the last job completes or is + * cancelled. + * + * All jobs in the transaction either complete successfully or fail/cancel as a + * group. Jobs wait for each other before completing. Cancelling one job + * cancels all jobs in the transaction. + */ +BlockJobTxn *block_job_txn_new(void); + +/** + * block_job_txn_unref: + * + * Release a reference that was previously acquired with block_job_txn_add_job + * or block_job_txn_new. If it's the last reference to the object, it will be + * freed. + */ +void block_job_txn_unref(BlockJobTxn *txn); + +/** + * block_job_txn_add_job: + * @txn: The transaction (may be NULL) + * @job: Job to add to the transaction + * + * Add @job to the transaction. The @job must not already be in a transaction. + * The caller must call either block_job_txn_unref() or block_job_completed() + * to release the reference that is automatically grabbed here. + */ +void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job); + +#endif |
