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[148/156] nbd: Don't export a block device with no medium.

Message ID 1404839947-1086-149-git-send-email-mdroth@linux.vnet.ibm.com
State New
Headers show

Commit Message

Michael Roth July 8, 2014, 5:18 p.m. UTC 
From: Hani Benhabiles <kroosec@gmail.com>

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 <kroosec@gmail.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 60fe4fac22895576973e317d7148b084c31cc64c)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 blockdev-nbd.c | 4 ++++
 1 file changed, 4 insertions(+)
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Patch

diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index 922cf56..a700d52 100644
--- 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;