1/*
2 * QEMU System Emulator block write threshold notification
3 *
4 * Copyright Red Hat, Inc. 2014
5 *
6 * Authors:
7 * Francesco Romani <fromani@redhat.com>
8 *
9 * This work is licensed under the terms of the GNU LGPL, version 2 or later.
10 * See the COPYING.LIB file in the top-level directory.
11 */
12
13#ifndef BLOCK_WRITE_THRESHOLD_H
14#define BLOCK_WRITE_THRESHOLD_H
15
16#include "block/block_int.h"
17
18/*
19 * bdrv_write_threshold_set:
20 *
21 * Set the write threshold for block devices, in bytes.
22 * Notify when a write exceeds the threshold, meaning the device
23 * is becoming full, so it can be transparently resized.
24 * To be used with thin-provisioned block devices.
25 *
26 * Use threshold_bytes == 0 to disable.
27 */
28void bdrv_write_threshold_set(BlockDriverState *bs, uint64_t threshold_bytes);
29
30/*
31 * bdrv_write_threshold_get
32 *
33 * Get the configured write threshold, in bytes.
34 * Zero means no threshold configured.
35 */
36uint64_t bdrv_write_threshold_get(const BlockDriverState *bs);
37
38/*
39 * bdrv_write_threshold_is_set
40 *
41 * Tell if a write threshold is set for a given BDS.
42 */
43bool bdrv_write_threshold_is_set(const BlockDriverState *bs);
44
45/*
46 * bdrv_write_threshold_exceeded
47 *
48 * Return the extent of a write request that exceeded the threshold,
49 * or zero if the request is below the threshold.
50 * Return zero also if the threshold was not set.
51 *
52 * NOTE: here we assume the following holds for each request this code
53 * deals with:
54 *
55 * assert((req->offset + req->bytes) <= UINT64_MAX)
56 *
57 * Please not there is *not* an actual C assert().
58 */
59uint64_t bdrv_write_threshold_exceeded(const BlockDriverState *bs,
60 const BdrvTrackedRequest *req);
61
62#endif
63