--- zzzz-none-000/linux-5.4.213/fs/overlayfs/file.c	2022-09-15 10:04:56.000000000 +0000
+++ miami-7690-761/linux-5.4.213/fs/overlayfs/file.c	2024-05-29 11:20:02.000000000 +0000
@@ -34,10 +34,23 @@
 	struct file *realfile;
 	const struct cred *old_cred;
 	int flags = file->f_flags | OVL_OPEN_FLAGS;
+	int acc_mode = ACC_MODE(flags);
+	int err;
+
+	if (flags & O_APPEND)
+		acc_mode |= MAY_APPEND;
 
 	old_cred = ovl_override_creds(inode->i_sb);
-	realfile = open_with_fake_path(&file->f_path, flags, realinode,
-				       current_cred());
+	err = inode_permission(realinode, MAY_OPEN | acc_mode);
+	if (err) {
+		realfile = ERR_PTR(err);
+	} else {
+		if (!inode_owner_or_capable(realinode))
+			flags &= ~O_NOATIME;
+
+		realfile = open_with_fake_path(&file->f_path, flags, realinode,
+					       current_cred());
+	}
 	revert_creds(old_cred);
 
 	pr_debug("open(%p[%pD2/%c], 0%o) -> (%p, 0%o)\n",
@@ -54,12 +67,6 @@
 	struct inode *inode = file_inode(file);
 	int err;
 
-	flags |= OVL_OPEN_FLAGS;
-
-	/* If some flag changed that cannot be changed then something's amiss */
-	if (WARN_ON((file->f_flags ^ flags) & ~OVL_SETFL_MASK))
-		return -EIO;
-
 	flags &= OVL_SETFL_MASK;
 
 	if (((flags ^ file->f_flags) & O_APPEND) && IS_APPEND(inode))