[RFC PATCH v4 5/8] ext4/066: verify LUFID dirdata operations

From: Artem Blagodarenko <[email protected]>

Test ext4 LUFID set/get operations on dirdata fields. This test
verifies that the EXT4_IOC_SET_LUFID ioctl can be used
to attach LUFID data to a directory entry and that `debugfs ls -lD`
can read this data.

Verification uses `debugfs ls -lD` to check for `fid:` markers,
indicating the presence of LUFID data in directory entries.

Signed-off-by: Artem Blagodarenko <[email protected]>
---
 tests/ext4/066     | 159 +++++++++++++++++++++++++++++++++++++++++++++
 tests/ext4/066.out |   4 ++
 2 files changed, 163 insertions(+)

diff --git a/tests/ext4/066 b/tests/ext4/066
new file mode 100755
index 00000000..979d9f1e
--- /dev/null
+++ b/tests/ext4/066
@@ -0,0 +1,159 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2026 The Lustre Collective. All Rights Reserved.
+# Author: Artem Blagodarenko <[email protected]>
+#
+# FS QA Test ext4/066
+#
+# Test the ext4 dirdata feature with LUFID ioctl functionality.
+# LUFID is a 16-byte identifier that can be attached
+# to directory entries. It is used for quick access to file metadata.
+# EXT4_IOC_SET_LUFID is an ioctl that allows LUFID data to be set on a
+# directory entry.
+
+. ./common/preamble
+_begin_fstest auto quick
+
+# Import common functions
+. ./common/filter
+. ./common/ext4
+
+_exclude_fs ext2
+_exclude_fs ext3
+
+_require_scratch_nocheck
+_require_command "$SET_LUFID_PROG"
+
+# Check if dirdata feature is supported (required for LUFID IOCTL)
+_require_scratch_dirdata()
+{
+	if test ! -f /sys/fs/ext4/features/dirdata ; then
+		_notrun "dirdata feature not supported by kernel (required for LUFID)"
+	fi
+
+	# Verify that mkfs supports dirdata
+	if ! $MKFS_EXT4_PROG -O dirdata -n $SCRATCH_DEV &>>$seqres.full ; then
+		_notrun "mkfs.ext4 does not support dirdata feature"
+	fi
+
+	# Verify kernel can mount filesystem with dirdata
+	if ! _scratch_mkfs -O dirdata &>>$seqres.full ; then
+		_notrun "failed to create filesystem with dirdata"
+	fi
+	if ! _try_scratch_mount &>>$seqres.full ; then
+		_notrun "kernel cannot mount filesystem with dirdata"
+	fi
+	_scratch_unmount
+}
+
+_require_scratch_dirdata
+
+_u32_to_le_hex()
+{
+	local v=$1
+	local h
+
+	h=$(printf '%08x' "$((v & 0xffffffff))")
+	printf '%s%s%s%s' "${h:6:2}" "${h:4:2}" "${h:2:2}" "${h:0:2}"
+}
+
+_build_default_expected_fid()
+{
+	local path=$1
+	local inode
+	local version
+	local ino_lo
+	local ver_hi ver_lo
+	local seq_hex oid_hex ver_hex
+
+	inode=$(stat -c '%i' "$path") || return 1
+	version=$(debugfs -R "stat <${inode}>" $SCRATCH_DEV 2>/dev/null | \
+		sed -n 's/.*Generation:[[:space:]]*\([0-9xa-fA-F]\+\).*/\1/p' | head -n 1)
+
+	if [ -z "$version" ]; then
+		return 1
+	fi
+
+	ino_lo=$((inode & 0xffffffff))
+	ver_lo=$((version & 0xffffffff))
+	ver_hi=$(((version >> 32) & 0xffffffff))
+
+	# Match lu_fid cast semantics: set_lufid stores u32 words in native memory
+	# order; debugfs reads lu_fid fields and prints f_seq/f_oid/f_ver.
+	# ext4 inode numbers are 32-bit so f_seq fits in 8 hex chars; avoid a
+	# 16-char $((16#...)) that would overflow for values >= 0x8000000000.
+	seq_hex="$(_u32_to_le_hex "$ino_lo")"
+	oid_hex="$(_u32_to_le_hex "$ver_lo")"
+	ver_hex="$(_u32_to_le_hex "$ver_hi")"
+
+	printf '[0x%x:0x%x:0x%x]' "$((16#$seq_hex))" "$((16#$oid_hex))" \
+		"$((16#$ver_hex))"
+}
+
+# Create a filesystem with dirdata feature
+_scratch_mkfs -O dirdata &>>$seqres.full
+_scratch_mount
+
+# Test: Create file and set multiple 16-byte LUFIDs on the same file
+echo "Test: Set multiple 16-byte LUFIDs on the same file"
+mkdir -p $SCRATCH_MNT/lufid_test
+echo "test content" > $SCRATCH_MNT/lufid_test/testfile.txt
+
+# Set both LUFIDs on the file at the same time (32 bytes total: two 16-byte FIDs)
+# First FID:  [part1 (8 bytes):part2 (4 bytes):part3 (4 bytes)]
+# Second FID: [part1 (8 bytes):part2 (4 bytes):part3 (4 bytes)]
+$SET_LUFID_PROG $SCRATCH_MNT/lufid_test testfile.txt >>$seqres.full
+if [ $? -ne 0 ]; then
+	echo "FAIL: Could not set both LUFIDs on testfile.txt"
+	_scratch_unmount
+	_check_scratch_fs
+	status=1
+	exit
+fi
+
+# Verify file is still accessible
+if [ ! -f $SCRATCH_MNT/lufid_test/testfile.txt ]; then
+	echo "FAIL: File not accessible after setting LUFIDs"
+	_scratch_unmount
+	_check_scratch_fs
+	status=1
+	exit
+fi
+
+# Verify file content is preserved
+content=$(cat $SCRATCH_MNT/lufid_test/testfile.txt 2>/dev/null)
+if [ "$content" != "test content" ]; then
+	echo "FAIL: File content not preserved after setting LUFIDs"
+	_scratch_unmount
+	_check_scratch_fs
+	status=1
+	exit
+fi
+
+expected_fid=$(_build_default_expected_fid $SCRATCH_MNT/lufid_test/testfile.txt)
+if [ -z "$expected_fid" ]; then
+	echo "FAIL: Could not calculate expected default LUFID"
+	_scratch_unmount
+	_check_scratch_fs
+	status=1
+	exit
+fi
+
+echo "Successfully set and verified both 16-byte LUFIDs on same file at the same time"
+
+# Dump directory structure to verify dirdata
+if ! _dump_dir_structure $SCRATCH_MNT/lufid_test testfile.txt "$expected_fid"; then
+	echo "FAIL: Stored LUFID does not match expected default value"
+	_scratch_unmount
+	_check_scratch_fs
+	status=1
+	exit
+fi
+
+# Cleanup and verify filesystem
+_scratch_unmount
+_check_scratch_fs
+
+# success, all done
+status=0
+exit
diff --git a/tests/ext4/066.out b/tests/ext4/066.out
new file mode 100644
index 00000000..4ec0fd6d
--- /dev/null
+++ b/tests/ext4/066.out
@@ -0,0 +1,4 @@
+QA output created by 066
+Test: Set multiple 16-byte LUFIDs on the same file
+Successfully set and verified both 16-byte LUFIDs on same file at the same time
+  Directory structure of lufid_test: OK (dirdata verified)
-- 
2.43.7