Commit 60fe4fac authored by Hani Benhabiles's avatar Hani Benhabiles Committed by Paolo Bonzini
Browse files

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: default avatarHani Benhabiles <kroosec@gmail.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent d4cba13b

blockdev-nbd.c

+4 −0
Original line number Diff line number Diff line
@@ -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;