nbd: Merge nbd_export_bitmap into nbd_export_new

We only have one caller that wants to export a bitmap name,
which it does right after creation of the export. But there is
still a brief window of time where an NBD client could see the
export but not the dirty bitmap, which a robust client would
have to interpret as meaning the entire image should be treated
as dirty.  Better is to eliminate the window entirely, by
inlining nbd_export_bitmap() into nbd_export_new(), and refusing
to create the bitmap in the first place if the requested bitmap
can't be located.

We also no longer need logic for setting a different bitmap
name compared to the bitmap being exported.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20190111194720.15671-8-eblake@redhat.com>

1 files changed, 1 insertions, 10 deletions

diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index cd86b38cda..c76d5416b9 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -175,7 +175,7 @@ void qmp_nbd_server_add(const char *device, bool has_name, const char *name,
         writable = false;
     }
 
-    exp = nbd_export_new(bs, 0, -1, name, NULL,
+    exp = nbd_export_new(bs, 0, -1, name, NULL, bitmap,
                          writable ? 0 : NBD_FLAG_READ_ONLY,
                          NULL, false, on_eject_blk, errp);
     if (!exp) {
@@ -186,15 +186,6 @@ void qmp_nbd_server_add(const char *device, bool has_name, const char *name,
      * our only way of accessing it is through nbd_export_find(), so we can drop
      * the strong reference that is @exp. */
     nbd_export_put(exp);
-
-    if (has_bitmap) {
-        Error *err = NULL;
-        nbd_export_bitmap(exp, bitmap, bitmap, &err);
-        if (err) {
-            error_propagate(errp, err);
-            nbd_export_remove(exp, NBD_SERVER_REMOVE_MODE_HARD, NULL);
-        }
-    }
 }
 
 void qmp_nbd_server_remove(const char *name,