qemu/block_int.h
Paolo Bonzini dc534f8fc0 block: document job API
I am not sure that these are really proper GtkDoc, but they follow
the existing documentation in block_int.h.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-04-05 14:54:40 +02:00

431 lines
15 KiB
C

/*
* QEMU System Emulator block driver
*
* Copyright (c) 2003 Fabrice Bellard
*
* 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 BLOCK_INT_H
#define BLOCK_INT_H
#include "block.h"
#include "qemu-option.h"
#include "qemu-queue.h"
#include "qemu-coroutine.h"
#include "qemu-timer.h"
#include "qapi-types.h"
#define BLOCK_FLAG_ENCRYPT 1
#define BLOCK_FLAG_COMPAT6 4
#define BLOCK_IO_LIMIT_READ 0
#define BLOCK_IO_LIMIT_WRITE 1
#define BLOCK_IO_LIMIT_TOTAL 2
#define BLOCK_IO_SLICE_TIME 100000000
#define NANOSECONDS_PER_SECOND 1000000000.0
#define BLOCK_OPT_SIZE "size"
#define BLOCK_OPT_ENCRYPT "encryption"
#define BLOCK_OPT_COMPAT6 "compat6"
#define BLOCK_OPT_BACKING_FILE "backing_file"
#define BLOCK_OPT_BACKING_FMT "backing_fmt"
#define BLOCK_OPT_CLUSTER_SIZE "cluster_size"
#define BLOCK_OPT_TABLE_SIZE "table_size"
#define BLOCK_OPT_PREALLOC "preallocation"
#define BLOCK_OPT_SUBFMT "subformat"
typedef struct BdrvTrackedRequest BdrvTrackedRequest;
typedef struct BlockIOLimit {
int64_t bps[3];
int64_t iops[3];
} BlockIOLimit;
typedef struct BlockIOBaseValue {
uint64_t bytes[2];
uint64_t ios[2];
} BlockIOBaseValue;
typedef struct BlockJob BlockJob;
/**
* 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 */
int (*set_speed)(BlockJob *job, int64_t value);
} 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;
/**
* 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 detected that the cancelled flag is
* true, it should not anymore issue any I/O operation to the
* block device.
*/
bool cancelled;
/**
* Set to false by the job while it is in a quiescent state, where
* no I/O is pending and cancellation can be processed without
* issuing new I/O. The busy flag must be set to false when the
* job goes to sleep on any condition that is not detected by
* #qemu_aio_wait, such as a timer.
*/
bool busy;
/** 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;
};
struct BlockDriver {
const char *format_name;
int instance_size;
int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename);
int (*bdrv_probe_device)(const char *filename);
int (*bdrv_open)(BlockDriverState *bs, int flags);
int (*bdrv_file_open)(BlockDriverState *bs, const char *filename, int flags);
int (*bdrv_read)(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors);
int (*bdrv_write)(BlockDriverState *bs, int64_t sector_num,
const uint8_t *buf, int nb_sectors);
void (*bdrv_close)(BlockDriverState *bs);
int (*bdrv_create)(const char *filename, QEMUOptionParameter *options);
int (*bdrv_set_key)(BlockDriverState *bs, const char *key);
int (*bdrv_make_empty)(BlockDriverState *bs);
/* aio */
BlockDriverAIOCB *(*bdrv_aio_readv)(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque);
BlockDriverAIOCB *(*bdrv_aio_writev)(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque);
BlockDriverAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs,
BlockDriverCompletionFunc *cb, void *opaque);
BlockDriverAIOCB *(*bdrv_aio_discard)(BlockDriverState *bs,
int64_t sector_num, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque);
int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
/*
* Efficiently zero a region of the disk image. Typically an image format
* would use a compact metadata representation to implement this. This
* function pointer may be NULL and .bdrv_co_writev() will be called
* instead.
*/
int coroutine_fn (*bdrv_co_write_zeroes)(BlockDriverState *bs,
int64_t sector_num, int nb_sectors);
int coroutine_fn (*bdrv_co_discard)(BlockDriverState *bs,
int64_t sector_num, int nb_sectors);
int coroutine_fn (*bdrv_co_is_allocated)(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, int *pnum);
/*
* Invalidate any cached meta-data.
*/
void (*bdrv_invalidate_cache)(BlockDriverState *bs);
/*
* Flushes all data that was already written to the OS all the way down to
* the disk (for example raw-posix calls fsync()).
*/
int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs);
/*
* Flushes all internal caches to the OS. The data may still sit in a
* writeback cache of the host OS, but it will survive a crash of the qemu
* process.
*/
int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs);
const char *protocol_name;
int (*bdrv_truncate)(BlockDriverState *bs, int64_t offset);
int64_t (*bdrv_getlength)(BlockDriverState *bs);
int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs);
int (*bdrv_write_compressed)(BlockDriverState *bs, int64_t sector_num,
const uint8_t *buf, int nb_sectors);
int (*bdrv_snapshot_create)(BlockDriverState *bs,
QEMUSnapshotInfo *sn_info);
int (*bdrv_snapshot_goto)(BlockDriverState *bs,
const char *snapshot_id);
int (*bdrv_snapshot_delete)(BlockDriverState *bs, const char *snapshot_id);
int (*bdrv_snapshot_list)(BlockDriverState *bs,
QEMUSnapshotInfo **psn_info);
int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs,
const char *snapshot_name);
int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi);
int (*bdrv_save_vmstate)(BlockDriverState *bs, const uint8_t *buf,
int64_t pos, int size);
int (*bdrv_load_vmstate)(BlockDriverState *bs, uint8_t *buf,
int64_t pos, int size);
int (*bdrv_change_backing_file)(BlockDriverState *bs,
const char *backing_file, const char *backing_fmt);
/* removable device specific */
int (*bdrv_is_inserted)(BlockDriverState *bs);
int (*bdrv_media_changed)(BlockDriverState *bs);
void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag);
void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked);
/* to control generic scsi devices */
int (*bdrv_ioctl)(BlockDriverState *bs, unsigned long int req, void *buf);
BlockDriverAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs,
unsigned long int req, void *buf,
BlockDriverCompletionFunc *cb, void *opaque);
/* List of options for creating images, terminated by name == NULL */
QEMUOptionParameter *create_options;
/*
* Returns 0 for completed check, -errno for internal errors.
* The check results are stored in result.
*/
int (*bdrv_check)(BlockDriverState* bs, BdrvCheckResult *result);
void (*bdrv_debug_event)(BlockDriverState *bs, BlkDebugEvent event);
/*
* Returns 1 if newly created images are guaranteed to contain only
* zeros, 0 otherwise.
*/
int (*bdrv_has_zero_init)(BlockDriverState *bs);
QLIST_ENTRY(BlockDriver) list;
};
/*
* Note: the function bdrv_append() copies and swaps contents of
* BlockDriverStates, so if you add new fields to this struct, please
* inspect bdrv_append() to determine if the new fields need to be
* copied as well.
*/
struct BlockDriverState {
int64_t total_sectors; /* if we are reading a disk image, give its
size in sectors */
int read_only; /* if true, the media is read only */
int keep_read_only; /* if true, the media was requested to stay read only */
int open_flags; /* flags used to open the file, re-used for re-open */
int encrypted; /* if true, the media is encrypted */
int valid_key; /* if true, a valid encryption key has been set */
int sg; /* if true, the device is a /dev/sg* */
int copy_on_read; /* if true, copy read backing sectors into image
note this is a reference count */
BlockDriver *drv; /* NULL means no media */
void *opaque;
void *dev; /* attached device model, if any */
/* TODO change to DeviceState when all users are qdevified */
const BlockDevOps *dev_ops;
void *dev_opaque;
char filename[1024];
char backing_file[1024]; /* if non zero, the image is a diff of
this file image */
char backing_format[16]; /* if non-zero and backing_file exists */
int is_temporary;
BlockDriverState *backing_hd;
BlockDriverState *file;
/* number of in-flight copy-on-read requests */
unsigned int copy_on_read_in_flight;
/* the time for latest disk I/O */
int64_t slice_time;
int64_t slice_start;
int64_t slice_end;
BlockIOLimit io_limits;
BlockIOBaseValue io_base;
CoQueue throttled_reqs;
QEMUTimer *block_timer;
bool io_limits_enabled;
/* I/O stats (display with "info blockstats"). */
uint64_t nr_bytes[BDRV_MAX_IOTYPE];
uint64_t nr_ops[BDRV_MAX_IOTYPE];
uint64_t total_time_ns[BDRV_MAX_IOTYPE];
uint64_t wr_highest_sector;
/* Whether the disk can expand beyond total_sectors */
int growable;
/* the memory alignment required for the buffers handled by this driver */
int buffer_alignment;
/* do we need to tell the quest if we have a volatile write cache? */
int enable_write_cache;
/* NOTE: the following infos are only hints for real hardware
drivers. They are not used by the block driver */
int cyls, heads, secs, translation;
BlockErrorAction on_read_error, on_write_error;
bool iostatus_enabled;
BlockDeviceIoStatus iostatus;
char device_name[32];
unsigned long *dirty_bitmap;
int64_t dirty_count;
int in_use; /* users other than guest access, eg. block migration */
QTAILQ_ENTRY(BlockDriverState) list;
QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
/* long-running background operation */
BlockJob *job;
};
void get_tmp_filename(char *filename, int size);
void bdrv_set_io_limits(BlockDriverState *bs,
BlockIOLimit *io_limits);
#ifdef _WIN32
int is_windows_drive(const char *filename);
#endif
/**
* block_job_create:
* @job_type: The class object for the newly-created job.
* @bs: The block
* @cb: Completion function for the job.
* @opaque: Opaque pointer value passed to @cb.
*
* 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,
BlockDriverCompletionFunc *cb, void *opaque);
/**
* 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
*
* Set a rate-limiting parameter for the job; the actual meaning may
* vary depending on the job type.
*/
int block_job_set_speed(BlockJob *job, int64_t value);
/**
* 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_cancel:
* @job: The job to be canceled.
*
* Asynchronously cancel the job and wait for it to reach a quiescent
* state. Note that the completion callback will still be called
* asynchronously, hence it is *not* valid to call #bdrv_delete
* immediately after #block_job_cancel_sync. Users of block jobs
* will usually protect the BlockDriverState objects with a reference
* count, should this be a concern.
*/
void block_job_cancel_sync(BlockJob *job);
/**
* stream_start:
* @bs: Block device to operate on.
* @base: Block device that will become the new base, or %NULL to
* flatten the whole backing file chain onto @bs.
* @base_id: The file name that will be written to @bs as the new
* backing file if the job completes. Ignored if @base is %NULL.
* @cb: Completion function for the job.
* @opaque: Opaque pointer value passed to @cb.
*
* Start a streaming operation on @bs. Clusters that are unallocated
* in @bs, but allocated in any image between @base and @bs (both
* exclusive) will be written to @bs. At the end of a successful
* streaming job, the backing file of @bs will be changed to
* @base_id in the written image and to @base in the live BlockDriverState.
*/
int stream_start(BlockDriverState *bs, BlockDriverState *base,
const char *base_id, BlockDriverCompletionFunc *cb,
void *opaque);
#endif /* BLOCK_INT_H */