xemu/include/block/block-copy.h
Emanuele Giuseppe Esposito 149009bef4 block-copy: atomic .cancelled and .finished fields in BlockCopyCallState
By adding acquire/release pairs, we ensure that .ret and .error_is_read
fields are written by block_copy_dirty_clusters before .finished is true,
and that they are read by API user after .finished is true.

The atomic here are necessary because the fields are concurrently modified
in coroutines, and read outside.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20210624072043.180494-6-eesposit@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2021-06-25 14:33:51 +03:00

95 lines
3.3 KiB
C

/*
* block_copy API
*
* Copyright (C) 2013 Proxmox Server Solutions
* Copyright (c) 2019 Virtuozzo International GmbH.
*
* Authors:
* Dietmar Maurer (dietmar@proxmox.com)
* Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef BLOCK_COPY_H
#define BLOCK_COPY_H
#include "block/block.h"
#include "qemu/co-shared-resource.h"
/* All APIs are thread-safe */
typedef void (*BlockCopyAsyncCallbackFunc)(void *opaque);
typedef struct BlockCopyState BlockCopyState;
typedef struct BlockCopyCallState BlockCopyCallState;
BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
int64_t cluster_size, bool use_copy_range,
BdrvRequestFlags write_flags,
Error **errp);
void block_copy_set_progress_meter(BlockCopyState *s, ProgressMeter *pm);
void block_copy_state_free(BlockCopyState *s);
int64_t block_copy_reset_unallocated(BlockCopyState *s,
int64_t offset, int64_t *count);
int coroutine_fn block_copy(BlockCopyState *s, int64_t offset, int64_t bytes,
bool ignore_ratelimit);
/*
* Run block-copy in a coroutine, create corresponding BlockCopyCallState
* object and return pointer to it. Never returns NULL.
*
* Caller is responsible to call block_copy_call_free() to free
* BlockCopyCallState object.
*
* @max_workers means maximum of parallel coroutines to execute sub-requests,
* must be > 0.
*
* @max_chunk means maximum length for one IO operation. Zero means unlimited.
*/
BlockCopyCallState *block_copy_async(BlockCopyState *s,
int64_t offset, int64_t bytes,
int max_workers, int64_t max_chunk,
BlockCopyAsyncCallbackFunc cb,
void *cb_opaque);
/*
* Free finished BlockCopyCallState. Trying to free running
* block-copy will crash.
*/
void block_copy_call_free(BlockCopyCallState *call_state);
/*
* Note, that block-copy call is marked finished prior to calling
* the callback.
*/
bool block_copy_call_finished(BlockCopyCallState *call_state);
bool block_copy_call_succeeded(BlockCopyCallState *call_state);
bool block_copy_call_failed(BlockCopyCallState *call_state);
bool block_copy_call_cancelled(BlockCopyCallState *call_state);
int block_copy_call_status(BlockCopyCallState *call_state, bool *error_is_read);
void block_copy_set_speed(BlockCopyState *s, uint64_t speed);
void block_copy_kick(BlockCopyCallState *call_state);
/*
* Cancel running block-copy call.
*
* Cancel leaves block-copy state valid: dirty bits are correct and you may use
* cancel + <run block_copy with same parameters> to emulate pause/resume.
*
* Note also, that the cancel is async: it only marks block-copy call to be
* cancelled. So, the call may be cancelled (block_copy_call_cancelled() reports
* true) but not yet finished (block_copy_call_finished() reports false).
*/
void block_copy_call_cancel(BlockCopyCallState *call_state);
BdrvDirtyBitmap *block_copy_dirty_bitmap(BlockCopyState *s);
void block_copy_set_skip_unallocated(BlockCopyState *s, bool skip);
#endif /* BLOCK_COPY_H */