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 #include "qemu/osdep.h" 14 #include "block/block-io.h" 15 #include "block/block_int.h" 16 #include "block/write-threshold.h" 17 #include "qapi/error.h" 18 #include "qapi/qapi-commands-block-core.h" 19 #include "qapi/qapi-events-block-core.h" 20 21 uint64_t bdrv_write_threshold_get(const BlockDriverState *bs) 22 { 23 return bs->write_threshold_offset; 24 } 25 26 void bdrv_write_threshold_set(BlockDriverState *bs, uint64_t threshold_bytes) 27 { 28 bs->write_threshold_offset = threshold_bytes; 29 } 30 31 void qmp_block_set_write_threshold(const char *node_name, 32 uint64_t threshold_bytes, 33 Error **errp) 34 { 35 BlockDriverState *bs; 36 AioContext *aio_context; 37 38 bs = bdrv_find_node(node_name); 39 if (!bs) { 40 error_setg(errp, "Device '%s' not found", node_name); 41 return; 42 } 43 44 aio_context = bdrv_get_aio_context(bs); 45 aio_context_acquire(aio_context); 46 47 bdrv_write_threshold_set(bs, threshold_bytes); 48 49 aio_context_release(aio_context); 50 } 51 52 void bdrv_write_threshold_check_write(BlockDriverState *bs, int64_t offset, 53 int64_t bytes) 54 { 55 int64_t end = offset + bytes; 56 uint64_t wtr = bs->write_threshold_offset; 57 58 if (wtr > 0 && end > wtr) { 59 qapi_event_send_block_write_threshold(bs->node_name, end - wtr, wtr); 60 61 /* autodisable to avoid flooding the monitor */ 62 bdrv_write_threshold_set(bs, 0); 63 } 64 } 65