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/*
* QEMU System Emulator block write threshold notification
*
* Copyright Red Hat, Inc. 2014
*
* Authors:
* Francesco Romani <fromani@redhat.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2 or later.
* See the COPYING.LIB file in the top-level directory.
*/
#ifndef BLOCK_WRITE_THRESHOLD_H
#define BLOCK_WRITE_THRESHOLD_H
#include <stdint.h>
#include "qemu/typedefs.h"
#include "qemu-common.h"
/*
* bdrv_write_threshold_set:
*
* Set the write threshold for block devices, in bytes.
* Notify when a write exceeds the threshold, meaning the device
* is becoming full, so it can be transparently resized.
* To be used with thin-provisioned block devices.
*
* Use threshold_bytes == 0 to disable.
*/
void bdrv_write_threshold_set(BlockDriverState *bs, uint64_t threshold_bytes);
/*
* bdrv_write_threshold_get
*
* Get the configured write threshold, in bytes.
* Zero means no threshold configured.
*/
uint64_t bdrv_write_threshold_get(const BlockDriverState *bs);
/*
* bdrv_write_threshold_is_set
*
* Tell if a write threshold is set for a given BDS.
*/
bool bdrv_write_threshold_is_set(const BlockDriverState *bs);
/*
* bdrv_write_threshold_exceeded
*
* Return the extent of a write request that exceeded the threshold,
* or zero if the request is below the threshold.
* Return zero also if the threshold was not set.
*
* NOTE: here we assume the following holds for each request this code
* deals with:
*
* assert((req->offset + req->bytes) <= UINT64_MAX)
*
* Please not there is *not* an actual C assert().
*/
uint64_t bdrv_write_threshold_exceeded(const BlockDriverState *bs,
const BdrvTrackedRequest *req);
#endif
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