[Qemu-devel] [PATCH 2/2] ISCSI: Force scsi-generic for MMC with blank disks

[Ronnie Sahlberg <ronniesahlberg@gmail.com>]

There is no bdrv_* API for the commands for burning a blank MMC disk
so when iSCSI LUNs are specified and the LUN is a MMC device with
0 available blocks. This is a blank disk so force scsi generic.

This allows the guest to talk directly to the target to burn data on
the disk.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
---
 block/iscsi.c |   13 +++++++++++--
 1 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/block/iscsi.c b/block/iscsi.c
index fb420ea..ca53afa 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -1017,10 +1017,19 @@ static int iscsi_open(BlockDriverState *bs, const char *filename, int flags)
     /* Medium changer or tape. We dont have any emulation for this so this must
      * be sg ioctl compatible. We force it to be sg, otherwise qemu will try
      * to read from the device to guess the image format.
+     * MMC device with no blocks contain a blank disk so force them to use sg
+     * too.
      */
-    if (iscsilun->type == TYPE_MEDIUM_CHANGER ||
-        iscsilun->type == TYPE_TAPE) {
+    switch (iscsilun->type) {
+    case TYPE_ROM:
+        if (iscsilun->num_blocks > 0) {
+            break;
+        }
+    case TYPE_MEDIUM_CHANGER:
+    case TYPE_TAPE:
         bs->sg = 1;
+    default:
+        break;
     }
 
     ret = 0;
-- 
1.7.3.1