virtio-blk: fix barrier support

Before issuing the barrier to the block driver we need to flush our oustanding
queue of write requests, as the flush is supposed to be issued after them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Christoph Hellwig 2010-05-19 12:40:09 +02:00 committed by Kevin Wolf
parent de6c8042ec
commit 618fbb8429

View File

@ -240,10 +240,20 @@ static void do_multiwrite(BlockDriverState *bs, BlockRequest *blkreq,
}
}
static void virtio_blk_handle_flush(VirtIOBlockReq *req)
static void virtio_blk_handle_flush(BlockRequest *blkreq, int *num_writes,
VirtIOBlockReq *req, BlockDriverState **old_bs)
{
BlockDriverAIOCB *acb;
/*
* Make sure all outstanding writes are posted to the backing device.
*/
if (*old_bs != NULL) {
do_multiwrite(*old_bs, blkreq, *num_writes);
}
*num_writes = 0;
*old_bs = req->dev->bs;
acb = bdrv_aio_flush(req->dev->bs, virtio_blk_flush_complete, req);
if (!acb) {
virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
@ -316,7 +326,8 @@ static void virtio_blk_handle_request(VirtIOBlockReq *req,
req->in = (void *)req->elem.in_sg[req->elem.in_num - 1].iov_base;
if (req->out->type & VIRTIO_BLK_T_FLUSH) {
virtio_blk_handle_flush(req);
virtio_blk_handle_flush(mrb->blkreq, &mrb->num_writes,
req, &mrb->old_bs);
} else if (req->out->type & VIRTIO_BLK_T_SCSI_CMD) {
virtio_blk_handle_scsi(req);
} else if (req->out->type & VIRTIO_BLK_T_OUT) {