From: J.Bruce Fields <bfields@fieldses.org>

Since exp_parent can fail by returning an error (-EAGAIN) in addition to by
returning NULL, we should check for that case in exp_rootfh.

(TODO: we should check that userland handles these errors too.)

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 fs/nfsd/export.c |    4 ++++
 1 files changed, 4 insertions(+)

diff -puN fs/nfsd/export.c~knfsd-nfsd-make-exp_rootfh-handle-exp_parent-errors fs/nfsd/export.c
--- a/fs/nfsd/export.c~knfsd-nfsd-make-exp_rootfh-handle-exp_parent-errors
+++ a/fs/nfsd/export.c
@@ -1104,6 +1104,10 @@ exp_rootfh(svc_client *clp, char *path, 
 		 path, nd.dentry, clp->name,
 		 inode->i_sb->s_id, inode->i_ino);
 	exp = exp_parent(clp, nd.mnt, nd.dentry, NULL);
+	if (IS_ERR(exp)) {
+		err = PTR_ERR(exp);
+		goto out;
+	}
 	if (!exp) {
 		dprintk("nfsd: exp_rootfh export not found.\n");
 		goto out;
_