autofs timeouts no longer working?

[Stephen Benoit <debian@magnumline.com>]

Hello, everyone.

I have been using autofs since Debian Potato.  Among other things, I use
it to automount my cd/dvd drive and release/unmount it after 15
idle seconds.  When I switched from Debian Woody to Sarge, the automount
processes never expired the unused mount again.

I have tried 3 different hosts on Sarge with the same effect whether I use
linux 2.6.15 with udev or 2.4.31 with devfs.  I also tried using the older
autofs3 protocol, but since it made no difference, I am using autofs4.

Packages used:
  autofs  4.1.3+4.1.4beta2
  mount:  2.12p-4sarge1

Using lsof, the directory tree looks ununsed by any processes.  Using
strace, the automount process sets the timeout by an ioctl(), but later
polling of the kernel by ioctl() always returns -EAGAIN, meaning nothing
is ready to be unmounted.

I reduced my test setup to the simplest I could, even removing any
symlinks in the device or mountpoint:

---vvv---/tmp/myautofile---vvv---
cdrw		-fstype=auto,ro	:/dev/scsi/host0/bus0/target0/lun0/cd
---^^^---/tmp/myautofile---^^^---

# mkdir /tmp/remov
# automount --debug --pid-file=/var/run/autofs/_tmp_remov.pid --timeout=15 /tmp/remov file /tmp/myautofile

# ls /tmp/remov/cdrw/
... after mounting, shows directory of cdrw.
... time passes, nothing is using the cd.
... /tmp/remov/cdrw never unmounts.

I welcome suggestions.  Has there been a configuration change for
autofs between Woody and Sarge that I missed?

Stephen Benoit
debian@magnumline.com