Re: [patch] umount loopback filessystems on autofs stop

[Joseph V Moss <jmoss@ichips.intel.com>]

Using /proc/mounts could be an issue for anyone trying to use this with a kernel
that truncates /proc/mounts.

> Hello,
> 
> The netfs scripts for Red Hat go through and umount any loopback devices
> before attempting to umount the encompassing filesystem.  This seems a sane
> thing to do (and I have a bug on said issue), so I've added similar
> functionality to the autofs init script.  Attached is a patch.  Comments
> encouraged.  Testing by debian folks would be nice, too.
> 
> -Jeff
> 
> --- autofs-4.1.3/samples/rc.autofs.in.umount-loopback	2004-09-02 15:55:21.722705296 -0400
> +++ autofs-4.1.3/samples/rc.autofs.in	2004-09-02 16:16:09.985940440 -0400
> @@ -351,6 +351,31 @@ function signal_automounts()
>  	return $RETVAL
>  }
>  
> +function umount_loopback()
> +{
> +    loops=`LC_ALL=C awk '!/^#/ && $1 ~ /^\/dev\/loop/ && $2 != "/" {print $2}' /proc/mounts`
> +    automounts=`LC_ALL=C awk '!/^#/ && $1 ~ /^automount/ {print $2}' /proc/mounts`
> +
> +    for l in $loops
> +    do
> +	for a in $automounts
> +	do
> +	    command="echo $l | grep -E '^$a'"
> +	    match=`echo $command | sh`
> +	    if [ -n "$match" ]; then
> +		echo ""
> +		echo -n $"Unmounting loopback filesystem $match:  "
> +		umount -d $match
> +		if [ $? -eq 0 ]; then
> +		    echo "done"
> +		else
> +		    echo "failed ($?)"
> +		fi
> +	    fi
> +	done
> +    done
> +}
> +
>  # Redhat start/stop function.
>  #
>  function redhat()
> @@ -386,6 +411,7 @@ case "$1" in
>  	if [ -z "`pidofproc $prog`" -a -z "`getmounts`" ]; then
>  		RETVAL=0
>  	else
> +		umount_loopback
>  		signal_automounts
>  		RETVAL=$?
>  	fi
> @@ -477,6 +503,7 @@ case "$1" in
>  	;;
>      stop)
>  	echo 'Stopping automounter.'
> +	umount_loopback
>  	start-stop-daemon --stop --quiet --signal USR2 --exec $DAEMON
>  	;;
>      reload|restart)
> 
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