ovl: properly print correct variable

In case of ovl_lookup_temp() failure, we currently print `err`
which is actually not initialized at all.

Instead, properly print PTR_ERR(whiteout) which is where the
actual error really is.

Address-Coverity-ID: 1647983 ("Uninitialized variables  (UNINIT)")
Fixes: 8afa0a7 ("ovl: narrow locking in ovl_whiteout()")
Signed-off-by: Antonio Quartulli <antonio@mandelbit.com>
Link: https://lore.kernel.org/20250721203821.7812-1-antonio@mandelbit.com
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: ordex

fs/overlayfs/dir.c

@@ -117,8 +117,9 @@ static struct dentry *ovl_whiteout(struct ovl_fs *ofs)
 		if (!IS_ERR(whiteout))
 			return whiteout;
 		if (PTR_ERR(whiteout) != -EMLINK) {
-			pr_warn("Failed to link whiteout - disabling whiteout inode sharing(nlink=%u, err=%i)\n",
-				ofs->whiteout->d_inode->i_nlink, err);
+			pr_warn("Failed to link whiteout - disabling whiteout inode sharing(nlink=%u, err=%lu)\n",
+				ofs->whiteout->d_inode->i_nlink,
+				PTR_ERR(whiteout));
 			ofs->no_shared_whiteout = true;
 		}
 	}