Commit 9a0cec66 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Fam Zheng
Browse files

mirror: use bdrv_drained_begin/bdrv_drained_end 



Ensure that there are no changes between the last check to
bdrv_get_dirty_count and the switch to the target.

There is already a bdrv_drained_end call, we only need to ensure
that bdrv_drained_begin is not called twice.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: default avatarFam Zheng <famz@redhat.com>
Message-Id: <1477565348-5458-4-git-send-email-pbonzini@redhat.com>
Signed-off-by: default avatarFam Zheng <famz@redhat.com>
parent bae8196d

block/mirror.c

+23 −12
Original line number Diff line number Diff line
@@ -622,6 +622,7 @@ static void coroutine_fn mirror_run(void *opaque) 
    MirrorExitData *data;

    BlockDriverState *bs = blk_bs(s->common.blk);

    BlockDriverState *target_bs = blk_bs(s->target);

    bool need_drain = true;

    int64_t length;

    BlockDriverInfo bdi;

    char backing_filename[2]; /* we only need 2 characters because we are only
@@ -757,11 +758,26 @@ static void coroutine_fn mirror_run(void *opaque) 
             * source has dirty data to copy!

             *

             * Note that I/O can be submitted by the guest while

             * mirror_populate runs.

             * mirror_populate runs, so pause it now.  Before deciding

             * whether to switch to target check one last time if I/O has

             * come in the meanwhile, and if not flush the data to disk.

             */

            trace_mirror_before_drain(s, cnt);

            bdrv_co_drain(bs);



            bdrv_drained_begin(bs);

            cnt = bdrv_get_dirty_count(s->dirty_bitmap);

            if (cnt > 0) {

                bdrv_drained_end(bs);

                continue;

            }



            /* The two disks are in sync.  Exit and report successful

             * completion.

             */

            assert(QLIST_EMPTY(&bs->tracked_requests));

            s->common.cancelled = false;

            need_drain = false;

            break;

        }



        ret = 0;
@@ -774,13 +790,6 @@ static void coroutine_fn mirror_run(void *opaque) 
        } else if (!should_complete) {

            delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0);

            block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);

        } else if (cnt == 0) {

            /* The two disks are in sync.  Exit and report successful

             * completion.

             */

            assert(QLIST_EMPTY(&bs->tracked_requests));

            s->common.cancelled = false;

            break;

        }

        s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);

    }
@@ -792,6 +801,7 @@ immediate_exit: 
         * the target is a copy of the source.

         */

        assert(ret < 0 || (!s->synced && block_job_is_cancelled(&s->common)));

        assert(need_drain);

        mirror_wait_for_all_io(s);

    }
@@ -804,9 +814,10 @@ immediate_exit: 


    data = g_malloc(sizeof(*data));

    data->ret = ret;

    /* Before we switch to target in mirror_exit, make sure data doesn't

     * change. */



    if (need_drain) {

        bdrv_drained_begin(bs);

    }

    block_job_defer_to_main_loop(&s->common, mirror_exit, data);

}