diff --git a/drivers/staging/lustre/lustre/llite/dcache.c b/drivers/staging/lustre/lustre/llite/dcache.c
index 549369739d80..dc30b4582234 100644
--- a/drivers/staging/lustre/lustre/llite/dcache.c
+++ b/drivers/staging/lustre/lustre/llite/dcache.c
@@ -74,6 +74,12 @@ static void ll_release(struct dentry *de)
  * an AST before calling d_revalidate_it().  The dentry still exists (marked
  * INVALID) so d_lookup() matches it, but we have no lock on it (so
  * lock_match() fails) and we spin around real_lookup().
+ *
+ * This race doesn't apply to lookups in d_alloc_parallel(), and for
+ * those we want to ensure that only one dentry with a given name is
+ * in ll_lookup_nd() at a time.  So allow invalid dentries to match
+ * while d_in_lookup().  We will be called again when the lookup
+ * completes, and can give a different answer then.
  */
 static int ll_dcompare(const struct dentry *dentry,
 		       unsigned int len, const char *str,
@@ -93,6 +99,10 @@ static int ll_dcompare(const struct dentry *dentry,
 	if (d_mountpoint((struct dentry *)dentry))
 		return 0;
 
+	/* ensure exclusion against parallel lookup of the same name */
+	if (d_in_lookup((struct dentry*)dentry))
+		return 0;
+
 	if (d_lustre_invalid(dentry))
 		return 1;