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 | */ |
28 | void 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 | */ |
36 | uint64_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 | */ |
43 | bool 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 | */ |
59 | uint64_t bdrv_write_threshold_exceeded(const BlockDriverState *bs, |
60 | const BdrvTrackedRequest *req); |
61 | |
62 | #endif |
63 | |