[xfstests,v2] generic: add a partial pages zeroing out test

Commit Message

Zhang Yi Dec. 25, 2024, 12:51 p.m. UTC

From: Zhang Yi <[e-mail]>

This addresses a data corruption issue encountered during partial page
zeroing in ext4 which the block size is smaller than the page size [1].
Add a new test which is expanded upon generic/567, this test performs a
zeroing range test that spans two partial pages to cover this case, and
also generalize it to work for non-4k page sizes.

Link: https://lore.kernel.org/linux-ext4/[e-mail]/ [1]
Signed-off-by: Zhang Yi <[e-mail]>
---
v1->v2:
 - Add a new test instead of modifying generic/567.
 - Generalize the test to work for non-4k page sizes.
v1: https://lore.kernel.org/fstests/[e-mail]/

 tests/generic/758     | 76 +++++++++++++++++++++++++++++++++++++++++++
 tests/generic/758.out |  3 ++
 2 files changed, 79 insertions(+)
 create mode 100755 tests/generic/758
 create mode 100644 tests/generic/758.out

Patch

diff --git a/tests/generic/758 b/tests/generic/758
new file mode 100755
index 00000000..e03b5e80
--- /dev/null
+++ b/tests/generic/758
@@ -0,0 +1,76 @@ 
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2024 Huawei.  All Rights Reserved.
+#
+# FS QA Test No. generic/758
+#
+# Test mapped writes against zero-range to ensure we get the data
+# correctly written. This can expose data corruption bugs on filesystems
+# where the block size is smaller than the page size.
+#
+# (generic/567 is a similar test but for punch hole.)
+#
+. ./common/preamble
+_begin_fstest auto quick rw zero
+
+# Override the default cleanup function.
+_cleanup()
+{
+	cd /
+	rm -r -f $verifyfile $testfile
+}
+
+# Import common functions.
+. ./common/filter
+
+_require_test
+_require_scratch
+_require_xfs_io_command "fzero"
+
+verifyfile=$TEST_DIR/verifyfile
+testfile=$SCRATCH_MNT/testfile
+
+pagesz=$(getconf PAGE_SIZE)
+
+_scratch_mkfs > /dev/null 2>&1
+_scratch_mount
+
+_dump_files()
+{
+	echo "---- testfile ----"
+	_hexdump $testfile
+	echo "---- verifyfile --"
+	_hexdump $verifyfile
+}
+
+# Build verify file, the data in this file should be consistent with
+# that in the test file.
+$XFS_IO_PROG -f -c "pwrite -S 0x58 0 $((pagesz * 3))" \
+		-c "pwrite -S 0x59 $((pagesz / 2)) $((pagesz * 2))" \
+		$verifyfile | _filter_xfs_io >> /dev/null
+
+# Zero out straddling two pages to check that the mapped write after the
+# range-zeroing are correctly handled.
+$XFS_IO_PROG -t -f \
+	-c "pwrite -S 0x58 0 $((pagesz * 3))" \
+	-c "mmap -rw 0 $((pagesz * 3))" \
+	-c "mwrite -S 0x5a $((pagesz / 2)) $((pagesz * 2))" \
+	-c "fzero $((pagesz / 2)) $((pagesz * 2))" \
+	-c "mwrite -S 0x59 $((pagesz / 2)) $((pagesz * 2))" \
+	-c "close"      \
+$testfile | _filter_xfs_io > $seqres.full
+
+echo "==== Pre-Remount ==="
+if ! cmp -s $testfile $verifyfile; then
+	echo "Data does not match pre-remount."
+	_dump_files
+fi
+_scratch_cycle_mount
+echo "==== Post-Remount =="
+if ! cmp -s $testfile $verifyfile; then
+	echo "Data does not match post-remount."
+	_dump_files
+fi
+
+status=0
+exit
diff --git a/tests/generic/758.out b/tests/generic/758.out
new file mode 100644
index 00000000..d01c1959
--- /dev/null
+++ b/tests/generic/758.out
@@ -0,0 +1,3 @@ 
+QA output created by 758
+==== Pre-Remount ===
+==== Post-Remount ==