autofs4 /net /proc/mounts problem

[Mitch Sako <msako@cadence.com>]

I’m seeing the following situation occur with 2.4.23 up through 2.4.27 and 
autofs 4.1.3 using /net access with a generic /etc/auto.net.  I tried 
'nonstrict' and 'nosymlink' in /etc/auto.net but that resulted in the 
mounts not working.

NFS Server foo has virtual nested exports:
/ on /dev/sda1
/bar on /dev/sdb1 (for example)

cd /net/foo/bar mounts both / and /bar which it finds from ‘showmount –e’

df shows foo:/ and foo:/bar mounted

/proc/mounts shows both, also.

I’m guessing what’s happening next is autofs4 tries to umount foo:/ before 
foo:/bar which yields a busy condition for foo:/, even though it’s not 
because foo:/bar is mounted above foo:/ on the client.

/proc/mounts starts filling up with foo:/bar entries at this point and 
fills up the mount table.

If I bring down the automount process, manually go through and umount all 
of the foo:/bar entries in /proc/mounts, clean up anything in /etc/mtab and 
then restart the automounter, everything seems to be OK.  Obviously, this 
is not acceptable.

Any ideas?