Bug 1007628 - [exportfs] Validate export entry fail. And when start nfs server, should not export the invalid entry;
[exportfs] Validate export entry fail. And when start nfs server, should not ...
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: nfs-utils (Show other bugs)
All Linux
high Severity unspecified
: rc
: ---
Assigned To: Steve Dickson
Yongcheng Yang
Depends On: 1007626
Blocks: 1007627
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Reported: 2013-09-12 22:17 EDT by Yin.JianHong
Modified: 2017-05-02 00:15 EDT (History)
3 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: 1007626
Last Closed: 2014-01-18 11:24:05 EST
Type: Bug
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

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Description Yin.JianHong 2013-09-12 22:17:55 EDT
+++ This bug was initially created as a clone of Bug #1007626 +++

Description of problem:
when start nfs server, we should verify the export entries:
  -when I export an directory in tmpfs without fsid= specified,
  -I can export successfuly, * but can not mount it from client.
  --the server log indicate: "Cannot export $dir, possibly unsupported filesystem or fsid= required"
  -We think that, exportfs should verify the export entries, if invalid then tell user that's invalid, cannot export

Version-Release number of selected component (if applicable):
all version in RHEL5.9 5.10 6.x 7.0

How reproducible:

Steps to Reproduce:
0. backup your /etc/exports
1. echo "/dev/shm  *(ro)" >/etc/exports
2. service nfs restart
3. exportfs   or  showmount -e

Actual results:
service nfs restart           ok
exportfs output:
/dev/shm      <world>

Expected results:
service nfs restart           should output error/warn: 
and should not export success, exportfs no output

Additional info:
Comment 2 Yin.JianHong 2013-09-13 08:32:22 EDT
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",
                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));
        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_xtabent = 1;
                        exp->m_mayexport = 1;
                        exp->m_changed = 1;
                        exp->m_warned = 0;

static void <<<- should return int value to indicate whether the path can export
validate_export(nfs_export *exp)
Comment 3 Yin.JianHong 2013-09-14 02:52:48 EDT
--- 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);
+	} else {
+		xlog(L_ERROR, "Assert: test_export() %s fail", path);
+		return;


this patch could avoid the test_export work fail.
Comment 4 Steve Dickson 2014-01-18 11:24:05 EST
The following error is now logged for file system requiring fsids

exportfs[4042]: exportfs: /dev/shm requires fsid= for NFS export
Comment 5 Yongcheng Yang 2017-05-02 00:15:41 EDT
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 $?
[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.

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