ocfs2: Fix endian bug in o2dlm protocol negotiation.

struct dlm_query_join_packet is made up of four one-byte fields.  They
are effectively in big-endian order already.  However, little-endian
machines swap them before putting the packet on the wire (because
query_join's response is a status, and that status is treated as a u32
on the wire).  Thus, a big-endian and little-endian machines will
treat this structure differently.

The solution is to have little-endian machines swap the structure when
converting from the structure to the u32 representation.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

1 files changed, 11 insertions, 9 deletions

diff --git a/fs/ocfs2/dlm/dlmcommon.h b/fs/ocfs2/dlm/dlmcommon.h
index 9843ee17ea2..1f939631ab7 100644
--- a/fs/ocfs2/dlm/dlmcommon.h
+++ b/fs/ocfs2/dlm/dlmcommon.h
@@ -602,17 +602,19 @@ enum dlm_query_join_response_code {
 	JOIN_PROTOCOL_MISMATCH,
 };
 
+struct dlm_query_join_packet {
+	u8 code;	/* Response code.  dlm_minor and fs_minor
+			   are only valid if this is JOIN_OK */
+	u8 dlm_minor;	/* The minor version of the protocol the
+			   dlm is speaking. */
+	u8 fs_minor;	/* The minor version of the protocol the
+			   filesystem is speaking. */
+	u8 reserved;
+};
+
 union dlm_query_join_response {
 	u32 intval;
-	struct {
-		u8 code;	/* Response code.  dlm_minor and fs_minor
-				   are only valid if this is JOIN_OK */
-		u8 dlm_minor;	/* The minor version of the protocol the
-				   dlm is speaking. */
-		u8 fs_minor;	/* The minor version of the protocol the
-				   filesystem is speaking. */
-		u8 reserved;
-	} packet;
+	struct dlm_query_join_packet packet;
 };
 
 struct dlm_lock_request