Commit 4e95314e authored by Kevin Wolf's avatar Kevin Wolf
Browse files

qcow2: Execute run_dependent_requests() without lock 



There's no reason for run_dependent_requests() to hold s->lock, and a
later patch will require that in fact the lock is not held.

Also, before this patch, run_dependent_requests() not only does what its
name suggests, but also removes the l2meta from the list of in-flight
requests. When changing this, it becomes an one-liner, so just inline it
completely.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 280d3735

block/qcow2.c

+16 −20
Original line number Diff line number Diff line
@@ -745,21 +745,6 @@ fail: 
    return ret;

}



static void run_dependent_requests(BDRVQcowState *s, QCowL2Meta *m)

{

    /* Take the request off the list of running requests */

    if (m->nb_clusters != 0) {

        QLIST_REMOVE(m, next_in_flight);

    }



    /* Restart all dependent requests */

    if (!qemu_co_queue_empty(&m->dependent_requests)) {

        qemu_co_mutex_unlock(&s->lock);

        qemu_co_queue_restart_all(&m->dependent_requests);

        qemu_co_mutex_lock(&s->lock);

    }

}



static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,

                           int64_t sector_num,

                           int remaining_sectors,
@@ -845,7 +830,15 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs, 
                goto fail;

            }



            run_dependent_requests(s, l2meta);

            /* Take the request off the list of running requests */

            if (l2meta->nb_clusters != 0) {

                QLIST_REMOVE(l2meta, next_in_flight);

            }



            qemu_co_mutex_unlock(&s->lock);

            qemu_co_queue_restart_all(&l2meta->dependent_requests);

            qemu_co_mutex_lock(&s->lock);



            g_free(l2meta);

            l2meta = NULL;

        }
@@ -858,13 +851,16 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs, 
    ret = 0;



fail:

    qemu_co_mutex_unlock(&s->lock);



    if (l2meta != NULL) {

        run_dependent_requests(s, l2meta);

        if (l2meta->nb_clusters != 0) {

            QLIST_REMOVE(l2meta, next_in_flight);

        }

        qemu_co_queue_restart_all(&l2meta->dependent_requests);

        g_free(l2meta);

    }



    qemu_co_mutex_unlock(&s->lock);



    qemu_iovec_destroy(&hd_qiov);

    qemu_vfree(cluster_data);

    trace_qcow2_writev_done_req(qemu_coroutine_self(), ret);
@@ -1152,7 +1148,7 @@ static int preallocate(BlockDriverState *bs) 
        /* There are no dependent requests, but we need to remove our request

         * from the list of in-flight requests */

        if (meta != NULL) {

            run_dependent_requests(bs->opaque, meta);

            QLIST_REMOVE(meta, next_in_flight);

        }



        /* TODO Preallocate data if requested */