btrfs: add helper to kill background process running _btrfs_stress_defrag

Killing a background process running _btrfs_stress_defrag() 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 "btrfs filesystem defrag" | 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.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>

6 files changed, 28 insertions, 30 deletions

diff --git a/common/btrfs b/common/btrfs
index cf320190b2..dd7bb6c26c 100644
--- a/common/btrfs
+++ b/common/btrfs
@@ -393,6 +393,20 @@ _btrfs_stress_defrag()
 	done
 }
 
+# Kill a background process running _btrfs_stress_defrag()
+_btrfs_kill_stress_defrag_pid()
+{
+       local defrag_pid=$1
+
+       # Ignore if process already died.
+       kill $defrag_pid &> /dev/null
+       wait $defrag_pid &> /dev/null
+       # Wait for the defrag operation to finish.
+       while ps aux | grep "btrfs filesystem defrag" | grep -qv grep; do
+               sleep 1
+       done
+}
+
 # stress btrfs by remounting it with different compression algorithms in a loop
 # run this with fsstress running at background could exercise the compression
 # code path and ensure no race when switching compression algorithm with constant
diff --git a/tests/btrfs/062 b/tests/btrfs/062
index a2639d6ccc..59d581bead 100755
--- a/tests/btrfs/062
+++ b/tests/btrfs/062
@@ -53,12 +53,7 @@ run_test()
 	echo "Wait for fsstress to exit and kill all background workers" >>$seqres.full
 	wait $fsstress_pid
 	_btrfs_kill_stress_balance_pid $balance_pid
-	kill $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_defrag_pid $defrag_pid
 
 	echo "Scrub the filesystem" >>$seqres.full
 	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
diff --git a/tests/btrfs/067 b/tests/btrfs/067
index 709db155d2..2bb00b875a 100755
--- a/tests/btrfs/067
+++ b/tests/btrfs/067
@@ -58,12 +58,8 @@ run_test()
 	wait $fsstress_pid
 
 	touch $stop_file
-	kill $defrag_pid
-	wait
-	# wait for btrfs defrag process to exit, otherwise it will block umount
-	while ps aux | grep "btrfs filesystem defrag" | grep -qv grep; do
-		sleep 1
-	done
+	wait $subvol_pid
+	_btrfs_kill_stress_defrag_pid $defrag_pid
 
 	echo "Scrub the filesystem" >>$seqres.full
 	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
diff --git a/tests/btrfs/070 b/tests/btrfs/070
index 54aa275c7d..cefa572300 100755
--- a/tests/btrfs/070
+++ b/tests/btrfs/070
@@ -60,17 +60,16 @@ run_test()
 
 	echo "Wait for fsstress to exit and kill all background workers" >>$seqres.full
 	wait $fsstress_pid
-	kill $replace_pid $defrag_pid
-	wait
+	kill $replace_pid
+	wait $replace_pid
 
-	# wait for the defrag and replace operations to finish
-	while ps aux | grep "btrfs filesystem defrag" | 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_defrag_pid $defrag_pid
+
 	echo "Scrub the filesystem" >>$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 6c15b51f04..505d0b578c 100755
--- a/tests/btrfs/072
+++ b/tests/btrfs/072
@@ -52,13 +52,8 @@ run_test()
 
 	echo "Wait for fsstress to exit and kill all background workers" >>$seqres.full
 	wait $fsstress_pid
-	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_defrag_pid $defrag_pid
 	_btrfs_kill_stress_scrub_pid $scrub_pid
 
 	echo "Scrub the filesystem" >>$seqres.full
diff --git a/tests/btrfs/074 b/tests/btrfs/074
index 9b22c62029..d51922d08b 100755
--- a/tests/btrfs/074
+++ b/tests/btrfs/074
@@ -52,16 +52,15 @@ run_test()
 
 	echo "Wait for fsstress to exit and kill all background workers" >>$seqres.full
 	wait $fsstress_pid
-	kill $defrag_pid $remount_pid
-	wait
-	# wait for the defrag and remount operations to finish
-	while ps aux | grep "btrfs filesystem defrag" | 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_defrag_pid $defrag_pid
+
 	echo "Scrub the filesystem" >>$seqres.full
 	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
 	if [ $? -ne 0 ]; then