bug#11844: du: continue processing after bind-mount induced dir-cycle

[Jim Meyering]

Paul Eggert wrote:
> On 07/02/2012 10:04 AM, Jim Meyering wrote:
>>       - read+stat all mount points at start-up
>
> This sounds like it might have problems on hosts that have
> lots of mount points, or where some mount points are remote.
> I've been on many systems where statting a remote
> mount point can take a long time, or even hang indefinitely.
>
> The problem with remote mounts might be attacked by using
> getmntent to find out which mount points are on the
> current file system and can therefore be safely statted
> (I haven't used getmntent enough to know whether this is feasible,
> sorry).

Since with bind mounts we care only about non-remote mount points,
we can call read_file_system_list to get the list, and then stat only
those mount point directories for which !mount_entry.me_remote
(and probably && !...me_dummy)