typedef enum {
BDRV_REQ_COPY_ON_READ = 0x1,
+ BDRV_REQ_ZERO_WRITE = 0x2,
} BdrvRequestFlags;
static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load);
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
BdrvRequestFlags flags);
static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
- int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
+ int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
+ BdrvRequestFlags flags);
static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs,
int64_t sector_num,
QEMUIOVector *qiov,
rwco->nb_sectors, rwco->qiov, 0);
} else {
rwco->ret = bdrv_co_do_writev(rwco->bs, rwco->sector_num,
- rwco->nb_sectors, rwco->qiov);
+ rwco->nb_sectors, rwco->qiov, 0);
}
}
BDRV_REQ_COPY_ON_READ);
}
+static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors)
+{
+ BlockDriver *drv = bs->drv;
+ QEMUIOVector qiov;
+ struct iovec iov;
+ int ret;
+
+ /* First try the efficient write zeroes operation */
+ if (drv->bdrv_co_write_zeroes) {
+ return drv->bdrv_co_write_zeroes(bs, sector_num, nb_sectors);
+ }
+
+ /* Fall back to bounce buffer if write zeroes is unsupported */
+ iov.iov_len = nb_sectors * BDRV_SECTOR_SIZE;
+ iov.iov_base = qemu_blockalign(bs, iov.iov_len);
+ memset(iov.iov_base, 0, iov.iov_len);
+ qemu_iovec_init_external(&qiov, &iov, 1);
+
+ ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, &qiov);
+
+ qemu_vfree(iov.iov_base);
+ return ret;
+}
+
/*
* Handle a write request in coroutine context
*/
static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
- int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
+ int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
+ BdrvRequestFlags flags)
{
BlockDriver *drv = bs->drv;
BdrvTrackedRequest req;
tracked_request_begin(&req, bs, sector_num, nb_sectors, true);
- ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov);
+ if (flags & BDRV_REQ_ZERO_WRITE) {
+ ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors);
+ } else {
+ ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov);
+ }
if (bs->dirty_bitmap) {
set_dirty_bitmap(bs, sector_num, nb_sectors, 1);
{
trace_bdrv_co_writev(bs, sector_num, nb_sectors);
- return bdrv_co_do_writev(bs, sector_num, nb_sectors, qiov);
+ return bdrv_co_do_writev(bs, sector_num, nb_sectors, qiov, 0);
+}
+
+int coroutine_fn bdrv_co_write_zeroes(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors)
+{
+ trace_bdrv_co_write_zeroes(bs, sector_num, nb_sectors);
+
+ return bdrv_co_do_writev(bs, sector_num, nb_sectors, NULL,
+ BDRV_REQ_ZERO_WRITE);
}
/**
acb->req.nb_sectors, acb->req.qiov, 0);
} else {
acb->req.error = bdrv_co_do_writev(bs, acb->req.sector,
- acb->req.nb_sectors, acb->req.qiov);
+ acb->req.nb_sectors, acb->req.qiov, 0);
}
acb->bh = qemu_bh_new(bdrv_co_em_bh, acb);