allow O_TMPFILE to work with O_WRONLY

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/open.c

@@ -844,6 +844,8 @@ static inline int build_open_flags(int flags, umode_t mode, struct open_flags *o
 		if ((flags & O_TMPFILE_MASK) != O_TMPFILE)
 			return -EINVAL;
 		acc_mode = MAY_OPEN | ACC_MODE(flags);
+		if (!(acc_mode & MAY_WRITE))
+			return -EINVAL;
 	} else if (flags & O_PATH) {
 		/*
 		 * If we have O_PATH in the open flag. Then we

include/uapi/asm-generic/fcntl.h

@@ -89,8 +89,8 @@
 #endif
 
 /* a horrid kludge trying to make sure that this will fail on old kernels */
-#define O_TMPFILE (__O_TMPFILE | O_DIRECTORY | O_RDWR)
-#define O_TMPFILE_MASK (__O_TMPFILE | O_DIRECTORY | O_CREAT | O_ACCMODE)      
+#define O_TMPFILE (__O_TMPFILE | O_DIRECTORY)
+#define O_TMPFILE_MASK (__O_TMPFILE | O_DIRECTORY | O_CREAT)      
 
 #ifndef O_NDELAY
 #define O_NDELAY	O_NONBLOCK