#!/bin/sh

# Copyright (C) 2011 Junjiro R. Okajima
#
# This program, aufs is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

verbose=0
if [ "$1" = -v ]
then
	verbose=1
	shift
fi

test $# -ne 2 &&
{
	echo Invalid argument
	echo Usage: $(basename $0) '[-v]' aufs_mntpnt branch_path
	echo '\tprint PIDs which make the branch busy and un-removable.'
	echo '\t-v prints additional information, the inode number in aufs,'
	echo '\tthe branch index, and the actual inode number on that branch.'
} 1>&2 &&
exit 1

set -eu
f=/etc/default/aufs
test ! -e $f &&
echo $f is not installed 1>&2 &&
exit 1
 . $f

mntent=$(FindMntEnt "$1")
test ! "$mntent" &&
echo No such aufs mount point "$1" 1>&2 &&
exit 1

mntpnt=$(echo $mntent | cut -f2 -d' ')

SetDir br "$2"
mntopts=$(MntOpts "$1")
si=$(echo $mntopts | sed -e 's/^.*,si=\([^,]*\),*.*$/\1/')
d=/sys/fs/aufs/si_$si
if [ -r $d/br0 ]
then
	# it may be very long and shell may not be able to handle as wildcard
	bindex=$(find $d -name 'br*' |
		xargs -r grep -l "^${br}=" |
		xargs -r basename |
		cut -c3-)
else
	bi=$(echo $mntpopts |
		sed -e 's/^.*,br://' |
		tr ':' '\n' |
		rev |
		cut -f2- -d= |
		rev |
		grep -n "^${br}=" |
		cut -f1 -d:)
	# the origin in aufs is zero.
	bindex=$(($bi - 1))
fi

########################################
# here we go
lsof -FDiR "$mntpnt" |
awk -v g_ppid=$$ \
	-v g_dev=$(stat -c %D "$mntpnt") \
	-v root=$AUFS_ROOT_INO \
'
function pr()
{
	if (inum) {
		print pid, inum;
		inum = "";
	}
}
/^p/ {
	pr();
	pid = substr($0, 2);
	do_print = 1;
	next;
}
/^R/ {
	ppid = substr($0, 2);
	if (ppid == g_ppid)
		do_print = 0;
	next;
}
/^D/ {
	dev = substr($0, 4);
	if (dev != g_dev)
		do_print = 0;
	next;
}
/^i/ && do_print {
	n = substr($0, 2);
	if (n != root)
		inum = inum " " n;
}
END {
	pr();
}
' |
#tee /dev/tty |
while read pid ino
do
	# it may be very long and shell may not be able to handle as parameters
	echo "$ino" |
	xargs -r auibusy "$mntpnt" $bindex |
	{
		if [ $verbose -eq 1 ]
		then
			sed -e s/^/$pid'	/'
		else
			test $(wc -c) -ne 0 &&
			echo $pid
		fi
	}
done |
uniq