xen/blktap-ioemu-close-fix.patch

Index: xen-3.3.1-testing/tools/blktap/drivers/blktapctrl.c
===================================================================
--- xen-3.3.1-testing.orig/tools/blktap/drivers/blktapctrl.c
+++ xen-3.3.1-testing/tools/blktap/drivers/blktapctrl.c
@@ -221,6 +221,28 @@ static void add_disktype(blkif_t *blkif,
 	entry->pprev = pprev;
 }
 
+static int qemu_instance_has_disks(int domid)
+{
+	int i;
+	int count = 0;
+	driver_list_entry_t *entry;
+
+	for (i = 0; i < MAX_DISK_TYPES; i++) {
+		entry = active_disks[i];
+		while (entry) {
+#ifdef ALWAYS_USE_IOEMU
+			if (entry->blkif->domid == domid)
+#else
+			if ((entry->blkif->domid == domid) && dtypes[i]->use_ioemu)
+#endif
+				count++;
+			entry = entry->next;
+		}
+	}
+
+	return (count != 0);
+}
+
 static int del_disktype(blkif_t *blkif)
 {
 	driver_list_entry_t *entry, **pprev;
@@ -245,8 +267,20 @@ static int del_disktype(blkif_t *blkif)
 	DPRINTF("DEL_DISKTYPE: Freeing entry\n");
 	free(entry);
 
+#ifdef ALWAYS_USE_IOEMU
+	return !qemu_instance_has_disks(blkif->domid);
+#else
+	/*
+	 * When using ioemu, all disks of one VM are connected to the same
+	 * qemu-dm instance. We may close the file handle only if there is
+	 * no other disk left for this domain.
+	 */
+	if (dtypes[type]->use_ioemu)
+		return !qemu_instance_has_disks(blkif->domid);
+
 	/* Caller should close() if no single controller, or list is empty. */
 	return (!dtypes[type]->single_handler || (active_disks[type] == NULL));
+#endif
 }
 
 static int write_msg(int fd, int msgtype, void *ptr, void *ptr2)