+test_398a() { # LU-4198
+ $LFS setstripe -c 1 -i 0 $DIR/$tfile
+ $LCTL set_param ldlm.namespaces.*.lru_size=clear
+
+ # request a new lock on client
+ dd if=/dev/zero of=$DIR/$tfile bs=1M count=1
+
+ dd if=/dev/zero of=$DIR/$tfile bs=1M count=1 oflag=direct conv=notrunc
+ local lock_count=$($LCTL get_param -n \
+ ldlm.namespaces.*-OST0000-osc-ffff*.lru_size)
+ [[ $lock_count -eq 0 ]] || error "lock should be cancelled by direct IO"
+
+ $LCTL set_param ldlm.namespaces.*-OST0000-osc-ffff*.lru_size=clear
+
+ # no lock cached, should use lockless IO and not enqueue new lock
+ dd if=/dev/zero of=$DIR/$tfile bs=1M count=1 oflag=direct conv=notrunc
+ lock_count=$($LCTL get_param -n \
+ ldlm.namespaces.*-OST0000-osc-ffff*.lru_size)
+ [[ $lock_count -eq 0 ]] || error "no lock should be held by direct IO"
+}
+run_test 398a "direct IO should cancel lock otherwise lockless"
+
+test_398b() { # LU-4198
+ which fio || skip_env "no fio installed"
+ $LFS setstripe -c -1 $DIR/$tfile
+
+ local size=12
+ dd if=/dev/zero of=$DIR/$tfile bs=1M count=$size
+
+ local njobs=4
+ echo "mix direct rw ${size}M to OST0 by fio with $njobs jobs..."
+ fio --name=rand-rw --rw=randrw --bs=$PAGE_SIZE --direct=1 \
+ --numjobs=$njobs --fallocate=none \
+ --iodepth=16 --allow_file_create=0 --size=$((size/njobs))M \
+ --filename=$DIR/$tfile &
+ bg_pid=$!
+
+ echo "mix buffer rw ${size}M to OST0 by fio with $njobs jobs..."
+ fio --name=rand-rw --rw=randrw --bs=$PAGE_SIZE \
+ --numjobs=$njobs --fallocate=none \
+ --iodepth=16 --allow_file_create=0 --size=$((size/njobs))M \
+ --filename=$DIR/$tfile || true
+ wait $bg_pid
+
+ rm -rf $DIR/$tfile
+}
+run_test 398b "DIO and buffer IO race"
+