ext4: Add a test for inline_data vs. DAX inode flag

Inline_data is mutually exclusive to DAX inode flag so enabling both
of them is not expected and triggers some errors.  It's a regression
test for kernel commit aa2f77920b74 ("ext4: disallow modifying DAX
inode flag if inline_data has been set")

Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

tests/ext4/047

@@ -0,0 +1,56 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2020 Fujitsu.  All Rights Reserved.
+#
+# FS QA Test 047
+#
+# This is a regression test for kernel patch:
+# commit aa2f77920b74 ("ext4: disallow modifying DAX inode flag if inline_data has been set")
+
+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 $seqres.full
+
+# real QA test starts here
+_supported_fs ext4
+_require_scratch_dax_mountopt "dax=always"
+_require_dax_iflag
+_require_scratch_ext4_feature "inline_data"
+
+TESTFILE=$SCRATCH_MNT/testfile
+
+_scratch_mkfs_ext4 -O inline_data > $seqres.full 2>&1
+
+_scratch_mount "-o dax=inode" >> $seqres.full 2>&1
+
+echo "Need to make some inline data..." > $TESTFILE
+
+# It's fine to disallow modifying DAX inode flag on the file which
+# has inline_data flag.
+if $XFS_IO_PROG -c "chattr +x" $TESTFILE >> $seqres.full 2>&1; then
+	_scratch_cycle_mount "dax=inode"
+	echo 'Append data' >> $TESTFILE
+fi
+
+# success, all done
+echo "Silence is golden"
+status=0
+exit

tests/ext4/047.out

@@ -0,0 +1,2 @@
+QA output created by 047
+Silence is golden

tests/ext4/group

@@ -49,6 +49,7 @@
 044 auto quick
 045 auto dir
 046 auto prealloc quick
+047 auto quick dax
 271 auto rw quick
 301 aio auto ioctl rw stress defrag
 302 aio auto ioctl rw stress defrag