xen: Don't peek behind the BlockDriverState abstraction

First offender is xen_config_dev_blk()'s use of disk->bdrv->filename.
Get the filename from disk->opts instead.  Same result, except for
snapshots: there, we now get the filename specified by the user
instead of the name of the temporary image created by bdrv_open().
Should be an improvement.

Second offender is blk_init()'s use of blkdev->bs->drv->format_name.
Simply use the appropriate interface to get the format name.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

hw/xen_devconfig.c

@@ -1,6 +1,5 @@
 #include "xen_backend.h"
 #include "blockdev.h"
-#include "block_int.h" /* XXX */
 
 /* ------------------------------------------------------------- */
 
@@ -99,10 +98,11 @@ int xen_config_dev_blk(DriveInfo *disk)
     int cdrom = disk->media_cd;
     const char *devtype = cdrom ? "cdrom" : "disk";
     const char *mode    = cdrom ? "r"     : "w";
+    const char *filename = qemu_opt_get(disk->opts, "file");
 
     snprintf(device_name, sizeof(device_name), "xvd%c", 'a' + disk->unit);
     xen_be_printf(NULL, 1, "config disk %d [%s]: %s\n",
-                  disk->unit, device_name, disk->bdrv->filename);
+                  disk->unit, device_name, filename);
     xen_config_dev_dirs("vbd", "qdisk", vdev, fe, be, sizeof(fe));
 
     /* frontend */
@@ -112,7 +112,7 @@ int xen_config_dev_blk(DriveInfo *disk)
     /* backend */
     xenstore_write_str(be, "dev",             device_name);
     xenstore_write_str(be, "type",            "file");
-    xenstore_write_str(be, "params",          disk->bdrv->filename);
+    xenstore_write_str(be, "params",          filename);
     xenstore_write_str(be, "mode",            mode);
 
     /* common stuff */

hw/xen_disk.c

@@ -40,7 +40,6 @@
 #include <xen/io/xenbus.h>
 
 #include "hw.h"
-#include "block_int.h"
 #include "qemu-char.h"
 #include "xen_blkif.h"
 #include "xen_backend.h"
@@ -650,7 +649,7 @@ static int blk_init(struct XenDevice *xendev)
     if (blkdev->file_size < 0) {
         xen_be_printf(&blkdev->xendev, 1, "bdrv_getlength: %d (%s) | drv %s\n",
                       (int)blkdev->file_size, strerror(-blkdev->file_size),
-                      blkdev->bs->drv ? blkdev->bs->drv->format_name : "-");
+                      bdrv_get_format_name(blkdev->bs) ?: "-");
         blkdev->file_size = 0;
     }