xref: /openbmc/qemu/include/block/write-threshold.h (revision de6cd7599b518f0c832cc85980196ec02c129a86)
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  /*
17   * bdrv_write_threshold_set:
18   *
19   * Set the write threshold for block devices, in bytes.
20   * Notify when a write exceeds the threshold, meaning the device
21   * is becoming full, so it can be transparently resized.
22   * To be used with thin-provisioned block devices.
23   *
24   * Use threshold_bytes == 0 to disable.
25   */
26  void bdrv_write_threshold_set(BlockDriverState *bs, uint64_t threshold_bytes);
27  
28  /*
29   * bdrv_write_threshold_get
30   *
31   * Get the configured write threshold, in bytes.
32   * Zero means no threshold configured.
33   */
34  uint64_t bdrv_write_threshold_get(const BlockDriverState *bs);
35  
36  /*
37   * bdrv_write_threshold_check_write
38   *
39   * Check whether the specified request exceeds the write threshold.
40   * If so, send a corresponding event and disable write threshold checking.
41   */
42  void bdrv_write_threshold_check_write(BlockDriverState *bs, int64_t offset,
43                                        int64_t bytes);
44  
45  #endif
46