[linux-cifs-client] Should recently added helper function access_flags_to_smbopen_mode() also catch the error case ?

[Günter Kukkukk]

Some days ago a helper function was added to interpret
access_mode into valid open modes:

+static int
+access_flags_to_smbopen_mode(const int access_flags)
+{
+       int masked_flags = access_flags & (GENERIC_READ | GENERIC_WRITE);
+
+       if (masked_flags == GENERIC_READ)
+               return SMBOPEN_READ;
+       else if (masked_flags == GENERIC_WRITE)
+               return SMBOPEN_WRITE;
+
+       /* just go for read/write */
+       return SMBOPEN_READWRITE;
+}
+

In case of neither passing GENERIC_READ nor GENERIC_WRITE - which
would be an internal error - the default code path 
(returning SMBOPEN_READWRITE) would be taken.
I think, we should at least send an error message to the log
and pass back "the least destructive mode SMBOPEN_READ". Or
should we flag an error condition?

My current replacement:

static int
access_flags_to_smbopen_mode(const int access_flags)
{
	int ret;
	int masked_flags = access_flags & (GENERIC_READ | GENERIC_WRITE);

	switch (masked_flags) {
	case GENERIC_READ:
		ret = SMBOPEN_READ;
		break;
	case GENERIC_WRITE:
		ret = SMBOPEN_WRITE;
		break;
	case (GENERIC_READ | GENERIC_WRITE):
		ret = SMBOPEN_READWRITE;
		break;
	default:
		cERROR(1, ("Internal error: Invalid access_flags passed"));
		ret = SMBOPEN_READ; /* BB ?? */
	}
	return ret;
}

Comments ?
Cheers, Günter