logfs: Return -EINVAL if filesystem image doesn't match

Signed-off-by: Joern Engel <joern@logfs.org>
diff --git a/fs/logfs/super.c b/fs/logfs/super.c
index 7fc4625..edd9948 100644
--- a/fs/logfs/super.c
+++ b/fs/logfs/super.c
@@ -413,7 +413,7 @@
 
 	page = find_super_block(sb);
 	if (!page)
-		return -EIO;
+		return -EINVAL;
 
 	ds = page_address(page);
 	super->s_size = be64_to_cpu(ds->ds_filesystem_size);