On Fri, Aug 10, 2018 at 07:36:17AM -0700, Andy Lutomirski wrote: > > > > 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? > > 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. First of all, that does NOT belong anywhere other than fs itself. Example: NFS. Not every attempt to mount something leads to creation of new fs instance; moreover, whether it will or not can't be predicted in general. PS: for pity sake, fix your MUA; 270-character lines are way over the top.
