[PATCH review 02/13] mnt: Refactor fs_fully_visible into mount_too_revealing

[Seth Forshee]

On Mon, Jun 20, 2016 at 12:21:19PM -0500, Eric W. Biederman wrote:
> Replace the call of fs_fully_visible in do_new_mount from before the
> new superblock is allocated with a call of mount_too_revealing after
> the superblock is allocated.   This winds up being a much better location
> for maintainability of the code.
> 
> The first change this enables is the replacement of FS_USERNS_VISIBLE
> with SB_I_USERNS_VISIBLE.  Moving the flag from struct filesystem_type
> to sb_iflags on the superblock.
> 
> Unfortunately mount_too_revealing fundamentally needs to touch
> mnt_flags adding several MNT_LOCKED_XXX flags at the appropriate
> times.  If the mnt_flags did not need to be touched the code
> could be easily moved into the filesystem specific mount code.
> 
> Signed-off-by: "Eric W. Biederman" <ebiederm at xmission.com>

Acked-by: Seth Forshee <seth.forshee at canonical.com>