On Thu, Feb 11, 2021 at 03:38:13PM +0000, Christoph Hellwig wrote:

quoted

+	if (!mountpoint)
+		return -ENODEV;
+
+	ret = user_path_at(AT_FDCWD, mountpoint,
+			     LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);

user_path_at handles an empty path, although you'll get EFAULT instead.
Do we care about the -ENODEV here?

The quotactl manpage documents EFAULT as error code for invalid addr or
special argument, so we really should return -EFAULT here.

Existing quotactl gets this wrong as well:

	if (!special) {
		if (cmds == Q_SYNC)
			return quota_sync_all(type);
		return -ENODEV;
	}

Should we fix this or is there userspace code that is confused by a changed
return value?

Sascha

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