[PATCH v2 32/32] selftests/ftrace: Add blktrace testcase

[Masami Hiramatsu <mhiramat@xxxxxxxxxx>]

Add a basic testcase for blktrace. For making it portable,
this test uses a loop device.

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
 tools/testing/selftests/ftrace/config              |    1 
 .../testing/selftests/ftrace/test.d/tracer/blk.tc  |   91 ++++++++++++++++++++
 2 files changed, 92 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/tracer/blk.tc

diff --git a/tools/testing/selftests/ftrace/config b/tools/testing/selftests/ftrace/config
index c2c8de4fafff..d999032442e1 100644
--- a/tools/testing/selftests/ftrace/config
+++ b/tools/testing/selftests/ftrace/config
@@ -5,6 +5,7 @@ CONFIG_TRACER_SNAPSHOT=y
 CONFIG_STACK_TRACER=y
 CONFIG_HIST_TRIGGERS=y
 CONFIG_SCHED_TRACER=y
+CONFIG_BLK_DEV_IO_TRACE=y
 CONFIG_PREEMPT_TRACER=y
 CONFIG_IRQSOFF_TRACER=y
 CONFIG_PREEMPTIRQ_DELAY_TEST=m
diff --git a/tools/testing/selftests/ftrace/test.d/tracer/blk.tc b/tools/testing/selftests/ftrace/test.d/tracer/blk.tc
new file mode 100644
index 000000000000..9d6e72810c8a
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/tracer/blk.tc
@@ -0,0 +1,91 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL2.0
+# description: Test blktrace
+
+IMG=$TMPDIR/fs.img
+MNTDIR=$TMPDIR/mnt
+
+if ! grep -wq "blk" available_tracers ; then
+  echo "blktrace is not supported"
+  exit_unsupported
+fi
+
+available_fs() { #fstype
+  grep -q $1 /proc/filesystems && which mkfs.$1
+}
+
+if available_fs ext3; then
+  FSTYPE=ext3
+elif available_fs ext4; then
+  FSTYPE=ext4
+elif available_fs ext2; then
+  FSTYPE=ext2
+elif available_fs xfs; then
+  FSTYPE=xfs
+elif available_fs btrfs; then
+  FSTYPE=btrfs
+else
+  echo "No available block-based filesystems"
+  exit_unresolved
+fi
+
+if ! which losetup; then
+  echo "No losetup found"
+  exit_unresolved
+fi
+LODEV=`losetup -f`
+LODEVTRACE=/sys/block/`basename $LODEV`/trace
+
+do_cleanup() {
+  if [ -d $MNTDIR ]; then
+   umount $MNTDIR ||:
+  fi
+  losetup -d $LODEV ||:
+  rm -f $IMG
+}
+
+# workload failure is not a tracer's failure
+workload_fail() {
+  do_cleanup
+  echo "Failed to run workload"
+  exit_unresolved
+}
+
+do_fail() {
+  do_cleanup
+  echo "Test failed"
+  exit 1
+}
+
+enable_lodevtrace() {
+  if [ `cat $LODEVTRACE/enable` -ne 1 ]; then
+    echo 1 > $LODEVTRACE/enable
+  fi
+}
+
+echo blk > current_tracer
+
+dd if=/dev/zero of=$IMG bs=1M count=10 &&\
+losetup $LODEV $IMG &&\
+mkfs.$FSTYPE $LODEV &&\
+mkdir -p $MNTDIR &&\
+mount -t $FSTYPE $LODEV $MNTDIR &&\
+enable_lodevtrace &&\
+dd if=/dev/urandom of=$MNTDIR/testfile bs=1M count=1 &&\
+sync &&\
+umount $MNTDIR || workload_fail
+
+grep -q "[dd]" trace || do_fail
+grep -q "[umount]" trace || do_fail
+echo > trace
+
+losetup $LODEV $IMG &&\
+mount -t $FSTYPE $LODEV $MNTDIR &&\
+cat $MNTDIR/testfile > /dev/null &&\
+echo 0 > $LODEVTRACE/enable &&\
+umount $MNTDIR || workload_fail
+
+grep -q "[cat]" trace || do_fail
+grep -q "[mount]" trace || do_fail
+
+do_cleanup