[PATCH 2/2] btrfs-progs: convert-tests: Add test case for multiply overflow

[Qu Wenruo <wqu@suse.com>]

The new test case will test whether btrfs-convert can handle 64G ext*
fs.

This exercise the cctx->total_bytes calculation where multiplying 4K
(unsigned int) and 16777216 (u32) could lead to bit overflow for
unsigned int and got 0, and screw up later free space calculation.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 .../018-fs-size-overflow/test.sh              | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100755 tests/convert-tests/018-fs-size-overflow/test.sh

diff --git a/tests/convert-tests/018-fs-size-overflow/test.sh b/tests/convert-tests/018-fs-size-overflow/test.sh
new file mode 100755
index 000000000000..2335225445f8
--- /dev/null
+++ b/tests/convert-tests/018-fs-size-overflow/test.sh
@@ -0,0 +1,22 @@
+#!/bin/bash
+# Check if btrfs-convert can handle an ext4 fs whose size is 64G.
+# That fs size could trigger a multiply overflow and screw up free space
+# calculation
+
+source "$TEST_TOP/common"
+source "$TEST_TOP/common.convert"
+
+setup_root_helper
+prepare_test_dev
+check_prereq btrfs-convert
+check_global_prereq mke2fs
+check_global_prereq truncate
+
+truncate -s 64g $TEST_DEV
+
+convert_test_prep_fs ext4 mke2fs -t ext4 -b 4096
+run_check_umount_test_dev
+
+# Unpatched btrfs-convert would fail half way due to corrupted free space
+# cache tree
+convert_test_do_convert
-- 
2.27.0