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