nbd: Don't export a block device with no medium.

The device is exported with erroneous values and can't be read. Before the patch: $ sudo nbd-client localhost -p 10809 /dev/nbd0 -name floppy0 Negotiation: ..size = 17592186044415MB bs=1024, sz=18446744073709547520 bytes $ sudo mount /dev/nbd0 /mnt/tmp/ mount: block device /dev/nbd0 is write-protected, mounting read-only mount: /dev/nbd0: can't read superblock After the patch: (qemu) nbd_server_add ide0-hd0 (qemu) nbd_server_add floppy0 Device 'floppy0' has no medium Signed-off-by: Hani Benhabiles <[email protected]> Cc: [email protected] Signed-off-by: Paolo Bonzini <[email protected]>
stefanha · Jun 27, 2014 · 60fe4fa · 60fe4fa
1 parent d4cba13
commit 60fe4fa
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
@@ -91,6 +91,10 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
         error_set(errp, QERR_DEVICE_NOT_FOUND, device);
         return;
     }
+    if (!bdrv_is_inserted(bs)) {
+        error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
+        return;
+    }
 
     if (!has_writable) {
         writable = false;