diff options
Diffstat (limited to 'include/block/write-threshold.h')
-rw-r--r-- | include/block/write-threshold.h | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/include/block/write-threshold.h b/include/block/write-threshold.h new file mode 100644 index 0000000..f1b899c --- /dev/null +++ b/include/block/write-threshold.h @@ -0,0 +1,64 @@ +/* + * QEMU System Emulator block write threshold notification + * + * Copyright Red Hat, Inc. 2014 + * + * Authors: + * Francesco Romani <fromani@redhat.com> + * + * This work is licensed under the terms of the GNU LGPL, version 2 or later. + * See the COPYING.LIB file in the top-level directory. + */ +#ifndef BLOCK_WRITE_THRESHOLD_H +#define BLOCK_WRITE_THRESHOLD_H + +#include <stdint.h> + +#include "qemu/typedefs.h" +#include "qemu-common.h" + +/* + * bdrv_write_threshold_set: + * + * Set the write threshold for block devices, in bytes. + * Notify when a write exceeds the threshold, meaning the device + * is becoming full, so it can be transparently resized. + * To be used with thin-provisioned block devices. + * + * Use threshold_bytes == 0 to disable. + */ +void bdrv_write_threshold_set(BlockDriverState *bs, uint64_t threshold_bytes); + +/* + * bdrv_write_threshold_get + * + * Get the configured write threshold, in bytes. + * Zero means no threshold configured. + */ +uint64_t bdrv_write_threshold_get(const BlockDriverState *bs); + +/* + * bdrv_write_threshold_is_set + * + * Tell if a write threshold is set for a given BDS. + */ +bool bdrv_write_threshold_is_set(const BlockDriverState *bs); + +/* + * bdrv_write_threshold_exceeded + * + * Return the extent of a write request that exceeded the threshold, + * or zero if the request is below the threshold. + * Return zero also if the threshold was not set. + * + * NOTE: here we assume the following holds for each request this code + * deals with: + * + * assert((req->offset + req->bytes) <= UINT64_MAX) + * + * Please not there is *not* an actual C assert(). + */ +uint64_t bdrv_write_threshold_exceeded(const BlockDriverState *bs, + const BdrvTrackedRequest *req); + +#endif |