ovl: don't fail copy up if no fileattr support on upper

commit 94fd19752b upstream.

Christoph Fritz is reporting that failure to copy up fileattr when upper
doesn't support fileattr or xattr results in a regression.

Return success in these failure cases; this reverts overlayfs to the old
behavior.

Add a pr_warn_once() in these cases to still let the user know about the
copy up failures.

Reported-by: Christoph Fritz <chf.fritz@googlemail.com>
Fixes: 72db82115d ("ovl: copy up sync/noatime fileattr flags")
Cc: <stable@vger.kernel.org> # v5.15
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/overlayfs/copy_up.c

@@ -157,7 +157,9 @@ static int ovl_copy_fileattr(struct inode *inode, struct path *old,
 	 */
 	if (oldfa.flags & OVL_PROT_FS_FLAGS_MASK) {
 		err = ovl_set_protattr(inode, new->dentry, &oldfa);
-		if (err)
+		if (err == -EPERM)
+			pr_warn_once("copying fileattr: no xattr on upper\n");
+		else if (err)
 			return err;
 	}
 
@@ -167,6 +169,14 @@ static int ovl_copy_fileattr(struct inode *inode, struct path *old,
 
 	err = ovl_real_fileattr_get(new, &newfa);
 	if (err) {
+		/*
+		 * Returning an error if upper doesn't support fileattr will
+		 * result in a regression, so revert to the old behavior.
+		 */
+		if (err == -ENOTTY || err == -EINVAL) {
+			pr_warn_once("copying fileattr: no support on upper\n");
+			return 0;
+		}
 		pr_warn("failed to retrieve upper fileattr (%pd2, err=%i)\n",
 			new, err);
 		return err;