Re: Adding subroot information to /proc/mounts, or obtaining that through other means

H. Peter Anvin
2007-06-20T22:44:18Z

Karel Zak wrote:
>
> Yeah. How about include propagation trees to this file?
>
> mountpoint + ID + relative path + type + options + propagation-flag +
> {peer,master}-mount-id
>
> / 0xa917800 / ext3 rw PRIVATE
> /mnt 0xa917100 / ext3 rw SHARED peer:0xa917100
> /tmp 0xa917f00 /1 ext3 rw SLAVE master:0xa917100
>

I think we're talking about a different meaning of "id" here... you seem
to be talking about the vfsmount pointer, whereas it was originally
proposed as mnt_sb->sb_dev. Both are useful, for different reasons of
course.

We should include mnt_devname as well.

People are a bit nervous about exposing kernel pointers in userspace, I
have noticed; would it be better to add a "mnt_id" field to struct
vfsmount; this can simply be a counter assigned when the structure is
assigned and then never changed (it might have to be a 64-bit counter,
but I don't think that adding 8 bytes to struct vfsmount should be a
huge deal.)

Does that service everyone's needs?

-hpa