xfs: more reflink tests

Create a couple of XFS-specific tests -- one to check that growing
and shrinking the refcount btree works and a second one to check
what happens when we hit maximum refcount.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

tests/xfs/169

@@ -0,0 +1,86 @@
+#! /bin/bash
+# FS QA Test No. 169
+#
+# Ensure that we can create enough distinct reflink entries to force creation
+# of a multi-level refcount btree.  Delete and recreate a few times to
+# exercise the refcount btree grow/shrink functions.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2016, Oracle and/or its affiliates.  All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it would be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write the Free Software Foundation,
+# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+#-----------------------------------------------------------------------
+
+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 /
+    umount $SCRATCH_MNT > /dev/null 2>&1
+    rm -rf $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/reflink
+
+# real QA test starts here
+_supported_os Linux
+_supported_fs xfs
+_require_scratch_reflink
+
+rm -f $seqres.full
+
+_scratch_mkfs >/dev/null 2>&1
+_scratch_mount
+
+testdir=$SCRATCH_MNT/test-$seq
+mkdir $testdir
+
+echo "Create the original file blocks"
+blksz="$(stat -f $testdir -c '%S')"
+nr_blks=$((8 * blksz / 12))
+
+for i in 1 2 x; do
+	_pwrite_byte 0x61 0 $((blksz * nr_blks)) $testdir/file1 >> $seqres.full
+
+	echo "$i: Reflink every other block"
+	seq 1 2 $((nr_blks - 1)) | while read nr; do
+		_reflink_range  $testdir/file1 $((nr * blksz)) \
+				$testdir/file2 $((nr * blksz)) $blksz >> $seqres.full
+	done
+	umount $SCRATCH_MNT
+	_check_scratch_fs
+	_scratch_mount
+
+	test $i = "x" && break
+
+	echo "$i: Delete both files"
+	rm -rf $testdir/file1 $testdir/file2
+	umount $SCRATCH_MNT
+	_check_scratch_fs
+	_scratch_mount
+done
+
+# success, all done
+status=0
+exit