LXR qemu/block/write-threshold.c

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