From: Mikulas Patocka <[email-masked]>

Exactly one of name, uuid or device must be specified when referencing
an existing device.  This removes the ambiguity (risking the wrong
device being updated) if two conflicting parameters were specified.
Previously one parameter got used and any others were ignored silently.

Signed-off-by: Mikulas Patocka <[email-masked]>
Signed-off-by: Alasdair G Kergon <[email-masked]>

---
 drivers/md/dm-ioctl.c |    6 ++++++
 1 file changed, 6 insertions(+)

Index: linux-3.0/drivers/md/dm-ioctl.c
===================================================================
--- linux-3.0.orig/drivers/md/dm-ioctl.c
+++ linux-3.0/drivers/md/dm-ioctl.c
@@ -739,10 +739,16 @@ static struct hash_cell *__find_device_h
 	struct hash_cell *hc = NULL;
 
 	if (*param->uuid) {
+		if (*param->name || param->dev)
+			return NULL;
+
 		hc = __get_uuid_cell(param->uuid);
 		if (!hc)
 			return NULL;
 	} else if (*param->name) {
+		if (param->dev)
+			return NULL;
+
 		hc = __get_name_cell(param->name);
 		if (!hc)
 			return NULL;