qemu/blockjob.h
Paolo Bonzini 32c81a4a6e block: introduce block job error
The following behaviors are possible:

'report': The behavior is the same as in 1.1.  An I/O error,
respectively during a read or a write, will complete the job immediately
with an error code.

'ignore': An I/O error, respectively during a read or a write, will be
ignored.  For streaming, the job will complete with an error and the
backing file will be left in place.  For mirroring, the sector will be
marked again as dirty and re-examined later.

'stop': The job will be paused and the job iostatus will be set to
failed or nospace, while the VM will keep running.  This can only be
specified if the block device has rerror=stop and werror=stop or enospc.

'enospc': Behaves as 'stop' for ENOSPC errors, 'report' for others.

In all cases, even for 'report', the I/O error is reported as a QMP
event BLOCK_JOB_ERROR, with the same arguments as BLOCK_IO_ERROR.

It is possible that while stopping the VM a BLOCK_IO_ERROR event will be
reported and will clobber the event from BLOCK_JOB_ERROR, or vice versa.
This is not really avoidable since stopping the VM completes all pending
I/O requests.  In fact, it is already possible now that a series of
BLOCK_IO_ERROR events are reported with rerror=stop, because vm_stop
calls bdrv_drain_all and this can generate further errors.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-09-28 19:40:56 +02:00

244 lines
7.2 KiB
C

/*
* 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.h"
/**
* BlockJobType:
*
* A class type for block job objects.
*/
typedef struct BlockJobType {
/** Derived BlockJob struct size */
size_t instance_size;
/** String describing the operation, part of query-block-jobs QMP API */
const char *job_type;
/** Optional callback for job types that support setting a speed limit */
void (*set_speed)(BlockJob *job, int64_t speed, Error **errp);
} BlockJobType;
/**
* BlockJob:
*
* Long-running operation on a BlockDriverState.
*/
struct BlockJob {
/** The job type, including the job vtable. */
const BlockJobType *job_type;
/** The block device on which the job is operating. */
BlockDriverState *bs;
/**
* 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 #qemu_aio_wait will ("sooner or later") reenter the coroutine.
*/
bool cancelled;
/**
* Set to true if the job is either paused, or will pause itself
* as soon as possible (if busy == true).
*/
bool 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 #qemu_aio_wait, such as a timer.
*/
bool busy;
/** 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. */
BlockDriverCompletionFunc *cb;
/** The opaque value that is passed to the completion function. */
void *opaque;
};
/**
* 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 BlockJobType *job_type, BlockDriverState *bs,
int64_t speed, BlockDriverCompletionFunc *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, QEMUClock *clock, int64_t ns);
/**
* block_job_complete:
* @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_complete(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_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.
*/
void block_job_resume(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_iostatus_reset:
* @job: The job whose I/O status should be reset.
*
* Reset I/O status on @job.
*/
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);
#endif