From 912521c9fa1a638e31c9a83fe29062b912e9fe5b Mon Sep 17 00:00:00 2001
From: Qu Wenruo <wqu@suse.com>
Date: Thu, 30 Jul 2020 20:17:35 +0800
Subject: [PATCH] btrfs: Add test to check if shrink works well with fstrim

There is a bug in trim code which leads to fstrim accessing beyond
device boundary.

The test case will check if fstrim, then shrink, then fstrim, all of
them works without problem.

The fix is titled "btrfs: trim: fix underflow in trim length to prevent
access beyond device boundary".

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
---
 tests/btrfs/217     | 62 +++++++++++++++++++++++++++++++++++++++++++++
 tests/btrfs/217.out |  2 ++
 tests/btrfs/group   |  1 +
 3 files changed, 65 insertions(+)
 create mode 100755 tests/btrfs/217
 create mode 100644 tests/btrfs/217.out

diff --git a/tests/btrfs/217 b/tests/btrfs/217
new file mode 100755
index 00000000..86dbd03c
--- /dev/null
+++ b/tests/btrfs/217
@@ -0,0 +1,62 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2020 SUSE Linux Products GmbH. All Rights Reserved.
+#
+# FS QA Test 217
+#
+# Test if the following workload would cause problem:
+# - fstrim
+# - shrink device
+# - fstrim
+#
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+
+# Modify as appropriate.
+_supported_fs btrfs
+_supported_os Linux
+_require_scratch_size $((5 * 1024 * 1024)) #kB
+_require_fstrim
+
+# Create a 5G fs
+_scratch_mkfs_sized $((5 * 1024 * 1024 * 1024)) >> $seqres.full
+_scratch_mount
+
+# Fstrim to populate the device->alloc_status CHUNK_TRIMMED bits
+$FSTRIM_PROG -v $SCRATCH_MNT >> $seqres.full 2>&1 || \
+	_notrun "FSTRIM not supported"
+
+
+# Shrink the fs to 4G, so the existing CHUNK_TRIMMED bits are beyond
+# device boundary
+$BTRFS_UTIL_PROG filesystem resize 1:-1G "$SCRATCH_MNT" >> $seqres.full
+
+# Do fstrim again to trigger the bug
+$FSTRIM_PROG -v $SCRATCH_MNT >> $seqres.full
+
+echo "Silence is golden"
+
+# success, all done
+status=0
+exit
diff --git a/tests/btrfs/217.out b/tests/btrfs/217.out
new file mode 100644
index 00000000..e8757ea4
--- /dev/null
+++ b/tests/btrfs/217.out
@@ -0,0 +1,2 @@
+QA output created by 217
+Silence is golden
diff --git a/tests/btrfs/group b/tests/btrfs/group
index ca90818b..8dcb2315 100644
--- a/tests/btrfs/group
+++ b/tests/btrfs/group
@@ -219,3 +219,4 @@
 214 auto quick send snapshot
 215 auto quick
 216 auto quick seed
+217 auto quick trim dangerous
-- 
2.30.2