(namespace) quota: Ensure qids map to the filesystem
BugLink: http://bugs.launchpad.net/bugs/1634964 Introduce the helper qid_has_mapping and use it to ensure that the quota system only considers qids that map to the filesystems s_user_ns. In practice for quota supporting filesystems today this is the exact same check as qid_valid. As only 0xffffffff aka (qid_t)-1 does not map into init_user_ns. Replace the qid_valid calls with qid_has_mapping as values come in from userspace. This is harmless today and it prepares the quota system to work on filesystems with quotas but mounted by unprivileged users. Call qid_has_mapping from dqget. This ensures the passed in qid has a prepresentation on the underlying filesystem. Previously this was unnecessary as filesystesm never had qids that could not map. With the introduction of filesystems outside of s_user_ns this will not remain true. All of this ensures the quota code never has to deal with qids that don't map to the underlying filesystem. Cc: Jan Kara <jack@suse.cz> Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> (backported from commit d49d3762) Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Acked-by: Tim Gardner <tim.gardner@canonical.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Showing
Please register or sign in to comment