btrfs-progs: tests: add test for zero-log

Simple test to verify that the log_root is reset after the command, but
we yet need to provide a testing image with log_root set to something
sensible or crafted images with borked log_root pointer.

Signed-off-by: David Sterba <dsterba@suse.cz>

tests/misc-tests/003-zero-log/test.sh

@@ -0,0 +1,66 @@
+#!/bin/bash
+# test zero-log
+
+source $TOP/tests/common
+
+check_prereq btrfs-show-super
+check_prereq mkfs.btrfs
+check_prereq btrfs
+
+if [ -z $TEST_DEV ]; then
+	echo "\$TEST_DEV not given, use $TOP/test/test.img as fallback" >> \
+		$RESULTS
+	TEST_DEV="$TOP/tests/test.img"
+
+	# Need at least 1G to avoid mixed block group, which extent tree
+	# rebuild doesn't support.
+	run_check truncate -s 1G $TEST_DEV
+fi
+
+if [ -z $TEST_MNT ];then
+	echo "    [NOTRUN] extent tree rebuild, need TEST_MNT variant"
+	exit 0
+fi
+
+get_log_root()
+{
+	local image
+
+	image="$1"
+	$TOP/btrfs-show-super "$image" | \
+		grep '^log_root\>' | awk '{print $2}'
+}
+get_log_root_level() {
+	local image
+
+	image="$1"
+	$TOP/btrfs-show-super "$image" | \
+		grep '^log_root_level' | awk '{print $2}'
+}
+
+test_zero_log()
+{
+	# FIXME: we need an image with existing log_root
+	run_check $SUDO_HELPER $TOP/mkfs.btrfs -f \
+		--rootdir $TOP/Documentation \
+		$TEST_DEV
+	run_check $TOP/btrfs-show-super $TEST_DEV
+	if [ "$1" = 'standalone' ]; then
+		run_check $TOP/btrfs rescue zero-log $TEST_DEV
+	else
+		run_check $TOP/btrfs-zero-log $TEST_DEV
+	fi
+	log_root=$(get_log_root $TEST_DEV)
+	log_root_level=$(get_log_root $TEST_DEV)
+	if [ "$log_root" != 0 ]; then
+		_fail "FAIL: log_root not reset"
+	fi
+	if [ "$log_root_level" != 0 ]; then
+		_fail "FAIL: log_root_level not reset"
+	fi
+	run_check $TOP/btrfs-show-super $TEST_DEV
+	run_check $SUDO_HELPER $TOP/btrfs check $TEST_DEV
+}
+
+test_zero_log standalone
+test_zero_log internal