[PATCH 04/10] btrfs: add helper to kill background process running _btrfs_stress_scrub

[fdmanana@kernel.org]

From: Filipe Manana <fdmanana@suse.com>

Killing a background process running _btrfs_stress_scrub() is not as
simple as sending a signal to the process and waiting for it to die.
Therefore we have the following logic to terminate such process:

   kill $pid
   wait $pid
   while ps aux | grep "scrub start" | grep -qv grep; do
       sleep 1
   done

Since this is repeated in several test cases, move this logic to a common
helper and use it in all affected test cases. This will help to avoid
repeating the same code again several times in upcoming changes.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 common/btrfs    | 14 ++++++++++++++
 tests/btrfs/061 |  7 +------
 tests/btrfs/066 |  8 ++------
 tests/btrfs/069 | 11 +++++------
 tests/btrfs/072 | 11 +++++------
 tests/btrfs/073 | 11 +++++------
 6 files changed, 32 insertions(+), 30 deletions(-)

diff --git a/common/btrfs b/common/btrfs
index e95cff7f..d0adeea1 100644
--- a/common/btrfs
+++ b/common/btrfs
@@ -349,6 +349,20 @@ _btrfs_stress_scrub()
 	done
 }
 
+# Kill a background process running _btrfs_stress_scrub()
+_btrfs_kill_stress_scrub_pid()
+{
+       local scrub_pid=$1
+
+       # Ignore if process already died.
+       kill $scrub_pid &> /dev/null
+       wait $scrub_pid &> /dev/null
+       # Wait for the scrub operation to finish.
+       while ps aux | grep "scrub start" | grep -qv grep; do
+               sleep 1
+       done
+}
+
 # stress btrfs by defragmenting every file/dir in a loop and compress file
 # contents while defragmenting if second argument is not "nocompress"
 _btrfs_stress_defrag()
diff --git a/tests/btrfs/061 b/tests/btrfs/061
index d0b55e48..b8b2706c 100755
--- a/tests/btrfs/061
+++ b/tests/btrfs/061
@@ -52,12 +52,7 @@ run_test()
 	echo "Wait for fsstress to exit and kill all background workers" >>$seqres.full
 	wait $fsstress_pid
 	_btrfs_kill_stress_balance_pid $balance_pid
-	kill $scrub_pid
-	wait $scrub_pid
-	# wait for the crub operation to finish
-	while ps aux | grep "scrub start" | grep -qv grep; do
-		sleep 1
-	done
+	_btrfs_kill_stress_scrub_pid $scrub_pid
 
 	echo "Scrub the filesystem" >>$seqres.full
 	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
diff --git a/tests/btrfs/066 b/tests/btrfs/066
index a29034bb..29821fdd 100755
--- a/tests/btrfs/066
+++ b/tests/btrfs/066
@@ -57,12 +57,8 @@ run_test()
 	wait $fsstress_pid
 
 	touch $stop_file
-	kill $scrub_pid
-	wait
-	# wait for the scrub operation to finish
-	while ps aux | grep "scrub start" | grep -qv grep; do
-		sleep 1
-	done
+	wait $subvol_pid
+	_btrfs_kill_stress_scrub_pid $scrub_pid
 
 	echo "Scrub the filesystem" >>$seqres.full
 	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
diff --git a/tests/btrfs/069 b/tests/btrfs/069
index 139dde48..20f44b39 100755
--- a/tests/btrfs/069
+++ b/tests/btrfs/069
@@ -59,17 +59,16 @@ run_test()
 
 	echo "Wait for fsstress to exit and kill all background workers" >>$seqres.full
 	wait $fsstress_pid
-	kill $replace_pid $scrub_pid
-	wait
+	kill $replace_pid
+	wait $replace_pid
 
-	# wait for the scrub and replace operations to finish
-	while ps aux | grep "scrub start" | grep -qv grep; do
-		sleep 1
-	done
+	# wait for the replace operation to finish
 	while ps aux | grep "replace start" | grep -qv grep; do
 		sleep 1
 	done
 
+	_btrfs_kill_stress_scrub_pid $scrub_pid
+
 	echo "Scrub the filesystem" >>$seqres.full
 	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
 	if [ $? -ne 0 ]; then
diff --git a/tests/btrfs/072 b/tests/btrfs/072
index 4b6b6fb5..6c15b51f 100755
--- a/tests/btrfs/072
+++ b/tests/btrfs/072
@@ -52,16 +52,15 @@ run_test()
 
 	echo "Wait for fsstress to exit and kill all background workers" >>$seqres.full
 	wait $fsstress_pid
-	kill $scrub_pid $defrag_pid
-	wait
-	# wait for the scrub and defrag operations to finish
-	while ps aux | grep "scrub start" | grep -qv grep; do
-		sleep 1
-	done
+	kill $defrag_pid
+	wait $defrag_pid
+	# wait for the defrag operation to finish
 	while ps aux | grep "btrfs filesystem defrag" | grep -qv grep; do
 		sleep 1
 	done
 
+	_btrfs_kill_stress_scrub_pid $scrub_pid
+
 	echo "Scrub the filesystem" >>$seqres.full
 	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
 	if [ $? -ne 0 ]; then
diff --git a/tests/btrfs/073 b/tests/btrfs/073
index b1604f94..49a4abd1 100755
--- a/tests/btrfs/073
+++ b/tests/btrfs/073
@@ -51,16 +51,15 @@ run_test()
 
 	echo "Wait for fsstress to exit and kill all background workers" >>$seqres.full
 	wait $fsstress_pid
-	kill $scrub_pid $remount_pid
-	wait
-	# wait for the scrub and remount operations to finish
-	while ps aux | grep "scrub start" | grep -qv grep; do
-		sleep 1
-	done
+	kill $remount_pid
+	wait $remount_pid
+	# wait for the remount operation to finish
 	while ps aux | grep "mount.*$SCRATCH_MNT" | grep -qv grep; do
 		sleep 1
 	done
 
+	_btrfs_kill_stress_scrub_pid $scrub_pid
+
 	echo "Scrub the filesystem" >>$seqres.full
 	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
 	if [ $? -ne 0 ]; then
-- 
2.43.0