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 #ifndef BLOCK_WRITE_THRESHOLD_H 13 #define BLOCK_WRITE_THRESHOLD_H 14 15 #include <stdint.h> 16 17 #include "qemu/typedefs.h" 18 #include "qemu-common.h" 19 20 /* 21 * bdrv_write_threshold_set: 22 * 23 * Set the write threshold for block devices, in bytes. 24 * Notify when a write exceeds the threshold, meaning the device 25 * is becoming full, so it can be transparently resized. 26 * To be used with thin-provisioned block devices. 27 * 28 * Use threshold_bytes == 0 to disable. 29 */ 30 void bdrv_write_threshold_set(BlockDriverState *bs, uint64_t threshold_bytes); 31 32 /* 33 * bdrv_write_threshold_get 34 * 35 * Get the configured write threshold, in bytes. 36 * Zero means no threshold configured. 37 */ 38 uint64_t bdrv_write_threshold_get(const BlockDriverState *bs); 39 40 /* 41 * bdrv_write_threshold_is_set 42 * 43 * Tell if a write threshold is set for a given BDS. 44 */ 45 bool bdrv_write_threshold_is_set(const BlockDriverState *bs); 46 47 /* 48 * bdrv_write_threshold_exceeded 49 * 50 * Return the extent of a write request that exceeded the threshold, 51 * or zero if the request is below the threshold. 52 * Return zero also if the threshold was not set. 53 * 54 * NOTE: here we assume the following holds for each request this code 55 * deals with: 56 * 57 * assert((req->offset + req->bytes) <= UINT64_MAX) 58 * 59 * Please not there is *not* an actual C assert(). 60 */ 61 uint64_t bdrv_write_threshold_exceeded(const BlockDriverState *bs, 62 const BdrvTrackedRequest *req); 63 64 #endif 65