Re: rootfs exposure in /proc/mounts

[Willy Tarreau <willy@w.ods.org>]

Hi !

I remember this discussion too, and am also used to symlink mtab to
/proc/mounts. But I also remember some people stating that /proc/mounts doesn't
contain all information (some mount flags, nfs options ...) which may be needed
for a mount -o remount, while mtab contains them.

I too agree that it's non-sense to have both mtab and /proc/mounts. If mounts
isn't usable, why keep it ? At the moment, the only reason why I would abandon
this symlink would be that mounts be removed from /proc entirely ! And I also
agree that mtab shouldn't be under /etc (this is the only file that needs to
be written to). At least, it should be moved to /var/state or something like
that, provided it's available early in the boot stage, but this issue is not a
kernel one anyway.

But at this time, I still think that a symlink to /proc/mounts is the safest
solution in embedded or diskless situations, because even if we cannot update
it for the very first mounts, at least it will be correct when /proc is
mounted.

May be we should just accept this case as a common one, and update tools
(mount, umount, df, ?) to be able to use both mtab and /proc/mounts, and simply
ignore any rootfs entry.

Just my 0.02 euros.
Willy