Com o GNU sed
sed -n '
/Volume/!d
:a
n
/lock mode/{
p
d
}
/^\s*$/!ba
c\NA
' <file>
Com o awk
awk '
BEGIN{
FS="\n"
RS="\n\n"
}
/lock mode/{
for(i=1;i<=NF;i++)
if($i ~ /lock mode/)
print $i
next
}
{
print "NA"
}
' <file>