Andy Lutomirski <luto@xxxxxxxxxxxxxx> writes: >> On Aug 10, 2018, at 7:05 AM, Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote: >> >> >> There is a serious problem with mount options today that fsopen does not >> address. The problem is that mount options are ignored for block based >> filesystems, and any other type of filesystem that follows the same >> pattern. >> > >> /dev/loop0 /root/loop0-noacl-noquota-nouser_xattr ext4 rw,relatime,nouser_xattr,noacl 0 0 >> /dev/loop0 /root/loop0-acl-quota-user_xattr ext4 rw,relatime,nouser_xattr,noacl 0 0 > > To make sure I understand correctly: the problem is that the second > mount ignored the options because the device was already mounted, > right? Yes. > For the new API, I think the only remotely sane approach is to refuse > to mount or init or whatever you call it an already mounted bdev. If > user code genuinely needs to bind-mount an existing mount that is > known only by its bdev, we can add a specific API just for that. Eric