[CIFS] Add posix (advisory) byte range locking support to cifs client

Samba (version 3) server support for this is also currently being
done.  This client code is in an experimental path (requires enabling
/proc/fs/cifs/Experimental) while it is being tested.

Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 79e7f5a..b866e3a 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -265,7 +265,10 @@
 			const __u64 offset, const __u32 numUnlock,
 			const __u32 numLock, const __u8 lockType,
 			const int waitFlag);
-
+extern int CIFSSMBPosixLock(const int xid, struct cifsTconInfo *tcon,
+			const __u16 smb_file_id, const int get_flag,
+			const __u64 len, const __u64 offset, 
+			const __u16 lock_type, const int waitFlag);
 extern int CIFSSMBTDis(const int xid, struct cifsTconInfo *tcon);
 extern int CIFSSMBLogoff(const int xid, struct cifsSesInfo *ses);