[Linux-cluster] directio problem

[孙俊伟]

Hi,all
	When the GFS's version was 6.0，its documents said that GFS supported directio。
But now is 6.1pre2 or 6.1pre3 with Linux kernel 2.6.8.1 or 2.6.9, does it support too?
I've tried some tests, the result showed negative. My test program has the lines as follow:

#define _GNU_SOURCE 1 //for the tag O_DIRECT.
fd=open(argv[1], O_RDONLY|O_DIRECT);
if(fd<0) {
		perror("open");
		return -1;
	}
readed=read(fd, buf, block_size);
if(readed<=0) {
			perror("read");
			break;
		}
close(fd);

the result is "1. fd=3,valid. 2.read return: Invalid argument"
I've run the same program on ext3 and gfs filesystem, the result is the same.

So what's the problem, the kernel 2.6 does not support, or some kernel config problem? 

Another problem: 
Do I need to (or must) update GFS from 6.1pre2 with 2.6.8.1 to 6.1pre3 with 2.6.9?
I see the cvs log "Lock_dlm and lock_gulm are broken ..."

Thanks for any reply! Best regards!

Luckey Sun