On Tue, Feb 13, 2001 at 10:23:53AM -0700, K. Leif D. Van Horn wrote:
> This concerns Linux 2.4.1 coda and podfuk/uservfs (which uses /dev/cfs0)
> to "mount" Zope ftp server contents.  Everything seems to work with
> the filesystem as far as lookups, reads, and writes.  The close system
> call seems to not propagate error state to my applications.
> 
> The way I see it, I should be able to write a message to the
> coda device (/dev/cfs0) at the end of the upcall.  This message
> contains the outputArgs union with result set to -1.  The application
> never sees close return a error status.  Here is a example
> perl script:

The Coda kernel module expects userspace to return positive error
numbers:

linux/fs/coda/upcall.c:740
    /* Op went through, interrupt or not... */
    if (req->uc_flags & REQ_WRITE) {
	    out = (union outputArgs *)req->uc_data;
	    /* here we map positive Venus errors to * kernel errors */
	    error = -out->oh.result;
	    CDEBUG(D_UPCALL, "upcall: (u,o,r) (%ld, %ld, %ld) out at %p\n", 
		   out->oh.unique, out->oh.opcode, out->oh.result, out);
	    *outSize = req->uc_outSize;
	    goto exit;
    }

The error is expected to be something like EINVAL. When we get back into the
VFS with such a negative error, errno is set to this value and close will
return -1.

So you would have to return something like EPARSE instead of -EPARSE.

Jan