tests: simplify removal of dangling bg procs

some tests left dangling bg processes originating in
lvm2 commands being able to spawn any bg polling process
(lvchange, vgchange, pvmove, lvconvert...)

Initial fn 'add_to_kill_list' should collect processes with
specific parameters (proc's command line and parent processes ID).
After testing finishes the fn kill_listed_processes should remove these
listed by 'add_to_kill_list'.

Unfortunately it proved to be prone to an error especially in scenarios
where cmd line of initiating command contained characters required to
be espaced before passing to shell script to make it work correctly.
(Or if cmd spawned more than one bg process with same cmd line. i.e.:
vgchange or lvchange).

The new implementation is much simpler. It uses env. variable (LVM_TEST_TAG)
for marking a process desired to be killed later or during test env. teardown.
(i.e.: LVM_TEST_TAG=kill_me_$PREFIX to kill only processes related to
current test environment)

5 files changed, 17 insertions, 31 deletions

diff --git a/test/lib/aux.sh b/test/lib/aux.sh
index 0e59d6e2c..24be32339 100644
--- a/test/lib/aux.sh
+++ b/test/lib/aux.sh
@@ -233,26 +233,18 @@ kill_sleep_kill_() {
 	fi
 }
 
-# $1 cmd line
-# $2 optional parms for pgrep
-add_to_kill_list() {
-	local p=$(pgrep ${@:2} -f "$1" 2>/dev/null)
-	test -z "$p" || echo "$p:$1" >> kill_list
+print_procs_by_tag_() {
+	ps -o pid=,args= ehax 2>/dev/null | grep -weLVM_TEST_TAG=${1:-kill_me_$PREFIX} 2>/dev/null || true
+}
+
+count_processes_with_tag() {
+	print_procs_by_tag_ | wc -l
 }
 
 kill_listed_processes() {
-	local tmp
-	local pid
-	local cmd
-	test -f kill_list || return 0
-	while read tmp; do
-		pid=${tmp%%:*}
-		cmd=${tmp##*:}
-		for tmp in $(pgrep -f "$cmd" -d ' '); do
-			test "$tmp" = "$pid" && kill -9 "$tmp"
-		done
-	done < kill_list
-	rm -f kill_list
+	while read pid b; do
+		test -z "$pid" || kill -9 $pid
+	done <<< $(print_procs_by_tag_ $@)
 }
 
 teardown() {
diff --git a/test/shell/pvmove-abort-all.sh b/test/shell/pvmove-abort-all.sh
index de6d8c9ac..5bca8a22f 100644
--- a/test/shell/pvmove-abort-all.sh
+++ b/test/shell/pvmove-abort-all.sh
@@ -50,12 +50,9 @@ if test -z "$backgroundarg" ; then
 	aux wait_pvmove_lv_ready "$vg1-pvmove0"
         lvs -a $vg $vg1
 else
-	"${cmd1[@]}"
-	aux add_to_kill_list "${cmd1[*]}" -P 1
-	"${cmd2[@]}"
-	aux add_to_kill_list "${cmd2[*]}" -P 1
-	"${cmd3[@]}"
-	aux add_to_kill_list "${cmd3[*]}" -P 1
+	LVM_TEST_TAG="kill_me_$PREFIX" "${cmd1[@]}"
+	LVM_TEST_TAG="kill_me_$PREFIX" "${cmd2[@]}"
+	LVM_TEST_TAG="kill_me_$PREFIX" "${cmd3[@]}"
 fi
 
 # test removal of all pvmove LVs
diff --git a/test/shell/pvmove-abort.sh b/test/shell/pvmove-abort.sh
index 3165c6f5f..233252176 100644
--- a/test/shell/pvmove-abort.sh
+++ b/test/shell/pvmove-abort.sh
@@ -40,10 +40,8 @@ if test -z "$backgroundarg" ; then
 	"${cmd2[@]}" &
 	aux wait_pvmove_lv_ready "$vg-pvmove1"
 else
-	"${cmd1[@]}"
-	aux add_to_kill_list "${cmd1[*]}" -P 1
-	"${cmd2[@]}"
-	aux add_to_kill_list "${cmd2[*]}" -P 1
+	LVM_TEST_TAG="kill_me_$PREFIX" "${cmd1[@]}"
+	LVM_TEST_TAG="kill_me_$PREFIX" "${cmd2[@]}"
 fi
 
 # remove specific device
diff --git a/test/shell/pvmove-basic.sh b/test/shell/pvmove-basic.sh
index d5b7845e6..f7830da80 100644
--- a/test/shell/pvmove-basic.sh
+++ b/test/shell/pvmove-basic.sh
@@ -334,9 +334,7 @@ check_and_cleanup_lvs_
 
 #COMM "pvmove abort"
 restore_lvs_
-cmd=(pvmove $mode -i100 -b "$dev1" "$dev3")
-"${cmd[@]}"
-aux add_to_kill_list "${cmd[*]}" -P 1
+LVM_TEST_TAG="kill_me_$PREFIX" pvmove $mode -i100 -b "$dev1" "$dev3"
 pvmove --abort
 check_and_cleanup_lvs_
 
diff --git a/test/shell/pvmove-restart.sh b/test/shell/pvmove-restart.sh
index 88dfebedb..b91f6244e 100644
--- a/test/shell/pvmove-restart.sh
+++ b/test/shell/pvmove-restart.sh
@@ -79,7 +79,7 @@ dmsetup table
 
 # Restart pvmove
 # use exclusive activation to have usable pvmove without cmirrord
-vgchange -aey $vg
+LVM_TEST_TAG="kill_me_$PREFIX" vgchange --config 'activation{polling_interval=10}' -aey $vg
 aux wait_pvmove_lv_ready "$vg-pvmove0"
 dmsetup table
 
@@ -90,6 +90,7 @@ pvmove --abort
 lvs -a -o+devices $vg
 
 lvremove -ff $vg
+aux kill_listed_processes
 done
 
 # Restore delayed device back