+static int
+#ifdef HAVE_D_REVALIDATE_NAMEIDATA
+zpl_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
+ unsigned int flags = (nd ? nd->flags : 0);
+#else
+zpl_revalidate(struct dentry *dentry, unsigned int flags)
+{
+#endif /* HAVE_D_REVALIDATE_NAMEIDATA */
+ zfs_sb_t *zsb = dentry->d_sb->s_fs_info;
+ int error;
+
+ if (flags & LOOKUP_RCU)
+ return (-ECHILD);
+
+ /*
+ * After a rollback negative dentries created before the rollback
+ * time must be invalidated. Otherwise they can obscure files which
+ * are only present in the rolled back dataset.
+ */
+ if (dentry->d_inode == NULL) {
+ spin_lock(&dentry->d_lock);
+ error = time_before(dentry->d_time, zsb->z_rollback_time);
+ spin_unlock(&dentry->d_lock);
+
+ if (error)
+ return (0);
+ }
+
+ /*
+ * The dentry may reference a stale inode if a mounted file system
+ * was rolled back to a point in time where the object didn't exist.
+ */
+ if (dentry->d_inode && ITOZ(dentry->d_inode)->z_is_stale)
+ return (0);
+
+ return (1);
+}