Re: Problems with NFS exports

[Florian Weimer <fw@deneb.enyo.de>]

Florian Weimer <fw@deneb.enyo.de> writes:

> I'm seeing weired errors with nfsctl():
>
> This works:
>
> nfsservctl(NFSCTL_EXPORT, "deneb.enyo.de", "/mnt/storage/2/backup/deneb/tmp", makedev(3, 66), ino 167772288, uid 65534, gid 65534) = 0
>
> But a subsequent call fails:
>
> nfsservctl(NFSCTL_EXPORT, "deneb.enyo.de", "/mnt/storage/2/backup/deneb", makedev(3, 66), ino 150995072, uid 65534, gid 65534) = -1 EINVAL (Invalid argument)
>
> I don't understand what makes the difference (the inode values are
> correct).  This is kernel 2.4.18 with XFS support, and the directory
> resides on an XFS file system.
>
> Any ideas?

(Full quote because of additional recipeint.)

It appears that a directory tree can only be exported once.  Is this
intentional?  If yes, the following patch should be applied (to
linux/fs/nfsd/export.c), so that the return value is more meaningful:

--- export.c	2002/08/07 09:22:11	1.1
+++ export.c	2002/08/07 09:22:28
@@ -219,6 +219,7 @@
 		goto finish;
 	}
 
+	err = -EBUSY;
 	if ((parent = exp_child(clp, dev, nd.dentry)) != NULL) {
 		dprintk("exp_export: export not valid (Rule 3).\n");
 		goto finish;


After this change, the userspace tools can issue are more meaningful
error message for this case.