btrfs: add helper to kill background process running _btrfs_stress_remount_compress

Killing a background process running _btrfs_stress_remount_compress() 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 $pid
    while ps aux | grep "mount.*$SCRATCH_MNT" | 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>
[ Restore 'wait $fsstress_pid' before 'kill $replace_pid' ]

6 files changed, 25 insertions, 32 deletions

diff --git a/common/btrfs b/common/btrfs
index dd7bb6c26c..e7df825ed4 100644
--- a/common/btrfs
+++ b/common/btrfs
@@ -421,6 +421,21 @@ _btrfs_stress_remount_compress()
 	done
 }
 
+# Kill a background process running _btrfs_stress_remount_compress()
+_btrfs_kill_stress_remount_compress_pid()
+{
+	local remount_pid=$1
+	local btrfs_mnt=$2
+
+	# Ignore if process already died.
+	kill $remount_pid &> /dev/null
+	wait $remount_pid &> /dev/null
+	# Wait for the remount loop to finish.
+	while ps aux | grep "mount.*${btrfs_mnt}" | grep -qv grep; do
+		sleep 1
+	done
+}
+
 # stress btrfs by replacing devices in a loop
 # Note that at least 3 devices are needed in SCRATCH_DEV_POOL and the last
 # device should be free(not used by btrfs)
diff --git a/tests/btrfs/063 b/tests/btrfs/063
index baf0c35649..5ee2837f89 100755
--- a/tests/btrfs/063
+++ b/tests/btrfs/063
@@ -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 $remount_pid
-	wait $remount_pid
-	# wait for the remount loop to finish
-	while ps aux | grep "mount.*$SCRATCH_MNT" | grep -qv grep; do
-		sleep 1
-	done
+	_btrfs_kill_stress_remount_compress_pid $remount_pid $SCRATCH_MNT
 
 	echo "Scrub the filesystem" >>$seqres.full
 	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
diff --git a/tests/btrfs/068 b/tests/btrfs/068
index 15fd41db97..db53254a15 100755
--- a/tests/btrfs/068
+++ b/tests/btrfs/068
@@ -58,12 +58,8 @@ run_test()
 	wait $fsstress_pid
 
 	touch $stop_file
-	kill $remount_pid
-	wait
-	# wait for the remount loop process to finish
-	while ps aux | grep "mount.*$SCRATCH_MNT" | grep -qv grep; do
-		sleep 1
-	done
+	wait $subvol_pid
+	_btrfs_kill_stress_remount_compress_pid $remount_pid $SCRATCH_MNT
 
 	echo "Scrub the filesystem" >>$seqres.full
 	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
diff --git a/tests/btrfs/071 b/tests/btrfs/071
index 6ebbd8cc3c..d9aaf3d561 100755
--- a/tests/btrfs/071
+++ b/tests/btrfs/071
@@ -59,16 +59,15 @@ run_test()
 
 	echo "Wait for fsstress to exit and kill all background workers" >>$seqres.full
 	wait $fsstress_pid
-	kill $replace_pid $remount_pid
-	wait
+	kill $replace_pid
+	wait $replace_pid
 
-	# wait for the remount and replace operations to finish
+	# wait for the replace operationss to finish
 	while ps aux | grep "replace start" | grep -qv grep; do
 		sleep 1
 	done
-	while ps aux | grep "mount.*$SCRATCH_MNT" | grep -qv grep; do
-		sleep 1
-	done
+
+	_btrfs_kill_stress_remount_compress_pid $remount_pid $SCRATCH_MNT
 
 	echo "Scrub the filesystem" >>$seqres.full
 	$BTRFS_UTIL_PROG scrub start -B $SCRATCH_MNT >>$seqres.full 2>&1
diff --git a/tests/btrfs/073 b/tests/btrfs/073
index 49a4abd113..503582862f 100755
--- a/tests/btrfs/073
+++ b/tests/btrfs/073
@@ -51,13 +51,7 @@ run_test()
 
 	echo "Wait for fsstress to exit and kill all background workers" >>$seqres.full
 	wait $fsstress_pid
-	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_remount_compress_pid $remount_pid $SCRATCH_MNT
 	_btrfs_kill_stress_scrub_pid $scrub_pid
 
 	echo "Scrub the filesystem" >>$seqres.full
diff --git a/tests/btrfs/074 b/tests/btrfs/074
index d51922d08b..6e93b36a97 100755
--- a/tests/btrfs/074
+++ b/tests/btrfs/074
@@ -52,13 +52,7 @@ run_test()
 
 	echo "Wait for fsstress to exit and kill all background workers" >>$seqres.full
 	wait $fsstress_pid
-	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_remount_compress_pid $remount_pid $SCRATCH_MNT
 	_btrfs_kill_stress_defrag_pid $defrag_pid
 
 	echo "Scrub the filesystem" >>$seqres.full