Re: [Qemu-devel] [PATCH V9 03/11] quorum: Add quorum_aio_writev and its dependencies.

["Benoît Canet" <benoit.canet@irqsave.net>]

Le Friday 04 Oct 2013 à 16:35:18 (+0200), Max Reitz a écrit :
> On 2013-10-02 14:39, Benoît Canet wrote:
> >Signed-off-by: Benoit Canet <benoit@irqsave.net>
> >---
> >  block/quorum.c | 123 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 123 insertions(+)
> >
> >diff --git a/block/quorum.c b/block/quorum.c
> >index 9557e61..b49e3c6 100644
> >--- a/block/quorum.c
> >+++ b/block/quorum.c
> >@@ -64,11 +64,134 @@ struct QuorumAIOCB {
> >      int vote_ret;
> >  };
> >+static void quorum_aio_cancel(BlockDriverAIOCB *blockacb)
> >+{
> >+    QuorumAIOCB *acb = container_of(blockacb, QuorumAIOCB, common);
> >+    bool finished = false;
> >+
> >+    /* Wait for the request to finish */
> >+    acb->finished = &finished;
> >+    while (!finished) {
> >+        qemu_aio_wait();
> >+    }
> Hm, wouldn't it be better to pass the cancel to the children?
> 
> Max

Hi Max,

Hi don't understand how you would do this.

Best regards

Benoît

> 
> >+}
> >+
> >+static AIOCBInfo quorum_aiocb_info = {
> >+    .aiocb_size         = sizeof(QuorumAIOCB),
> >+    .cancel             = quorum_aio_cancel,
> >+};
> >+
> >+/* return the first error code get by each individual callbacks */
> >+static int quorum_get_first_error(QuorumAIOCB *acb)
> >+{
> >+    BDRVQuorumState *s = acb->bqs;
> >+    int i, ret = 0;
> >+
> >+    for (i = 0; i < s->total; i++) {
> >+        ret = acb->aios[i].ret;
> >+        if (ret) {
> >+            return ret;
> >+        }
> >+    }
> >+
> >+    /* should not pass here */
> >+    assert(false);
> >+}
> >+
> >+static void quorum_aio_finalize(QuorumAIOCB *acb)
> >+{
> >+    BDRVQuorumState *s = acb->bqs;
> >+    int ret;
> >+
> >+    ret = s->threshold <= acb->success_count ? 0 : quorum_get_first_error(acb);
> >+
> >+    acb->common.cb(acb->common.opaque, ret);
> >+    if (acb->finished) {
> >+        *acb->finished = true;
> >+    }
> >+    g_free(acb->aios);
> >+    qemu_aio_release(acb);
> >+}
> >+
> >+static QuorumAIOCB *quorum_aio_get(BDRVQuorumState *s,
> >+                                   BlockDriverState *bs,
> >+                                   QEMUIOVector *qiov,
> >+                                   uint64_t sector_num,
> >+                                   int nb_sectors,
> >+                                   BlockDriverCompletionFunc *cb,
> >+                                   void *opaque)
> >+{
> >+    QuorumAIOCB *acb = qemu_aio_get(&quorum_aiocb_info, bs, cb, opaque);
> >+    int i;
> >+
> >+    acb->bqs = s;
> >+    acb->sector_num = sector_num;
> >+    acb->nb_sectors = nb_sectors;
> >+    acb->qiov = qiov;
> >+    acb->aios = g_new0(QuorumSingleAIOCB, s->total);
> >+    acb->count = 0;
> >+    acb->success_count = 0;
> >+    acb->finished = NULL;
> >+    acb->is_read = false;
> >+    acb->vote_ret = 0;
> >+
> >+    for (i = 0; i < s->total; i++) {
> >+        acb->aios[i].buf = NULL;
> >+        acb->aios[i].ret = 0;
> >+        acb->aios[i].parent = acb;
> >+    }
> >+
> >+    return acb;
> >+}
> >+
> >+static void quorum_aio_cb(void *opaque, int ret)
> >+{
> >+    QuorumSingleAIOCB *sacb = opaque;
> >+    QuorumAIOCB *acb = sacb->parent;
> >+    BDRVQuorumState *s = acb->bqs;
> >+
> >+    sacb->ret = ret;
> >+    acb->count++;
> >+    if (ret == 0) {
> >+        acb->success_count++;
> >+    }
> >+    assert(acb->count <= s->total);
> >+    assert(acb->success_count <= s->total);
> >+    if (acb->count < s->total) {
> >+        return;
> >+    }
> >+
> >+    quorum_aio_finalize(acb);
> >+}
> >+
> >+static BlockDriverAIOCB *quorum_aio_writev(BlockDriverState *bs,
> >+                                          int64_t sector_num,
> >+                                          QEMUIOVector *qiov,
> >+                                          int nb_sectors,
> >+                                          BlockDriverCompletionFunc *cb,
> >+                                          void *opaque)
> >+{
> >+    BDRVQuorumState *s = bs->opaque;
> >+    QuorumAIOCB *acb = quorum_aio_get(s, bs, qiov, sector_num, nb_sectors,
> >+                                      cb, opaque);
> >+    int i;
> >+
> >+    for (i = 0; i < s->total; i++) {
> >+        acb->aios[i].aiocb = bdrv_aio_writev(&s->bs[i], sector_num, qiov,
> >+                                             nb_sectors, &quorum_aio_cb,
> >+                                             &acb->aios[i]);
> >+    }
> >+
> >+    return &acb->common;
> >+}
> >+
> >  static BlockDriver bdrv_quorum = {
> >      .format_name        = "quorum",
> >      .protocol_name      = "quorum",
> >      .instance_size      = sizeof(BDRVQuorumState),
> >+
> >+    .bdrv_aio_writev    = quorum_aio_writev,
> >  };
> >  static void bdrv_quorum_init(void)
> 
>