[PATCH v2] block/035: test return EIO from BLKRRPART

[Saranya Muruganandam <saranyamohan@google.com>]

When we fail to reread the partition superblock from the disk, due to
bad sector or bad disk etc, BLKRRPART should fail with EIO.
Simulate failure for the entire block device and run
"blockdev --rereadpt" and expect it to fail and return EIO instead of
pass.

Link: https://lore.kernel.org/all/20240405014253.748627-1-saranyamohan@google.com/
Signed-off-by: Saranya Muruganandam <saranyamohan@google.com>
---
 tests/block/035     | 87 +++++++++++++++++++++++++++++++++++++++++++++
 tests/block/035.out |  3 ++
 2 files changed, 90 insertions(+)
 create mode 100755 tests/block/035
 create mode 100644 tests/block/035.out

diff --git a/tests/block/035 b/tests/block/035
new file mode 100755
index 0000000..d4e67fd
--- /dev/null
+++ b/tests/block/035
@@ -0,0 +1,87 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-3.0+
+# Copyright (C) 2024 Google LLC
+#
+# Regression test for BLKRRPART.
+#
+# If we fail to read the partition table due to bad sector or other IO
+# failures, running "blockdev --rereadpt" should fail and return
+# -EIO.  On a buggy kernel, it passes unexpectedly.
+
+. tests/block/rc
+
+DESCRIPTION="test return EIO from BLKRRPART for whole-dev"
+QUICK=1
+
+DEBUGFS_MNT="/sys/kernel/debug/fail_make_request"
+PROBABILITY=0
+TIMES=0
+VERBOSE=0
+MAKE_FAIL=0
+
+_have_debugfs() {
+	if [[ ! -d "${DEBUGFS_MNT}" ]]; then
+		SKIP_REASONS+=("debugfs does not exist")
+		return 1
+	fi
+	return 0
+}
+
+requires() {
+	_have_debugfs
+}
+
+save_fail_make_request()
+{
+	# Save existing global fail_make_request settings
+	PROBABILITY=$(cat "${DEBUGFS_MNT}"/probability)
+	TIMES=$(cat "${DEBUGFS_MNT}"/times)
+	VERBOSE=$(cat "${DEBUGFS_MNT}"/verbose)
+
+	# Save TEST_DEV make-it-fail setting
+	MAKE_FAIL=$(cat "${TEST_DEV_SYSFS}"/make-it-fail)
+}
+
+allow_fail_make_request()
+{
+	# Allow global fail_make_request feature
+	echo 100 > "${DEBUGFS_MNT}"/probability
+	echo 9999999 > "${DEBUGFS_MNT}"/times
+	echo 0 > "${DEBUGFS_MNT}"/verbose
+
+	# Force TEST_DEV device failure
+	echo 1 > "${TEST_DEV_SYSFS}"/make-it-fail
+}
+
+restore_fail_make_request()
+{
+	echo "${MAKE_FAIL}" > "${TEST_DEV_SYSFS}"/make-it-fail
+
+	# Disallow global fail_make_request feature
+	echo "${PROBABILITY}" > "${DEBUGFS_MNT}"/probability
+	echo "${TIMES}" > "${DEBUGFS_MNT}"/times
+	echo "${VERBOSE}" > "${DEBUGFS_MNT}"/verbose
+}
+
+test_device() {
+	echo "Running ${TEST_NAME}"
+
+	# Save configuration
+	save_fail_make_request
+
+	# set up device for failure
+	allow_fail_make_request
+
+	# Check rereading partitions on bad disk cannot open $TEST_DEV: Input/output error
+	blockdev --rereadpt "${TEST_DEV}" &> "$FULL"
+	if grep -q "Input/output error" "$FULL"; then
+		echo "Return EIO for BLKRRPART on bad disk"
+	else
+		echo "Did not return EIO for BLKRRPART on bad disk"
+	fi
+
+	# Restore TEST_DEV device to original state
+	restore_fail_make_request
+
+	echo "Test complete"
+}
diff --git a/tests/block/035.out b/tests/block/035.out
new file mode 100644
index 0000000..0f97f6b
--- /dev/null
+++ b/tests/block/035.out
@@ -0,0 +1,3 @@
+Running block/035
+Return EIO for BLKRRPART on bad disk
+Test complete
-- 
2.44.0.683.g7961c838ac-goog