Bug 1007628

Debug, and review the code of exportfs,
find that: this is a bug of exportfs(also about kernel):

static int test_export(char *path, int with_fsid)
{
        char buf[1024];
        int fd, n;

        sprintf(buf, "-test-client- %s 3 %d -1 -1 0\n",
                path,
                with_fsid ? NFSEXP_FSID : 0);
        fd = open("/proc/net/rpc/nfsd.export/channel", O_WRONLY);
        if (fd < 0)
                return 0;
        n = write(fd, buf, strlen(buf));
        close(fd);
        if (n < 0)
                return 0;
        return 1;
}

1. if the path is an tmpfs(no uuid), and with_fsid==0,
this function test_export still return 1 (write success). that's wrong.

2. and another problem: validate_export() just generate log and return void.
We think that validate_export() should return an int value to indicate whether the path can export. And in export_all(), should not export the path if invalid;

static void
export_all(int verbose)
{
        nfs_export      *exp;
        int             i;

        for (i = 0; i < MCL_MAXTYPES; i++) {
                for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
                        if (verbose)
                                printf("exporting %s:%s\n",
                                       exp->m_client->m_hostname,
                                       exp->m_export.e_path);
                        exp->m_xtabent = 1;
                        exp->m_mayexport = 1;
                        exp->m_changed = 1;
                        exp->m_warned = 0;
                        validate_export(exp);
                }
        }
}


static void <<<- should return int value to indicate whether the path can export
validate_export(nfs_export *exp)
{

#BEGIN
--- exportfs.c	2013-06-06 15:12:58.881567360 +0800
+++ exportfs.c.new	2013-09-14 14:50:56.719877598 +0800
@@ -475,6 +475,9 @@ validate_export(nfs_export *exp)
 			xlog(L_ERROR, "%s does not support NFS export", path);
 		return;
 
+	} else {
+		xlog(L_ERROR, "Assert: test_export() %s fail", path);
+		return;
 	}
 }

#END

this patch could avoid the test_export work fail.

The following error is now logged for file system requiring fsids

exportfs[4042]: exportfs: /dev/shm requires fsid= for NFS export

This issue is actually that "exportfs" should NOT show the invalid entries.

For examples:
[root ~]# exportfs -ua
[root ~]# exportfs -i *:/not.exist
exportfs: Failed to stat /not.exist: No such file or directory
[root ~]# echo $?
1
[root ~]# exportfs 
/not.exist    	<world>  <<<<<<<<<<< Invalid path is exported anyway
[root ~]# 

However, as the rhel6 bug 1007627 and rhel5 bug 1007626 are both closed as WONTFIX, updating this one to be WONTFIX too. Please correct me if there's any concern.