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/179

@@ -0,0 +1,118 @@
+#! /bin/bash
+# FS QA Test No. 179
+#
+# See how well reflink handles overflowing reflink counts.
+#
+#-----------------------------------------------------------------------
+# 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 /
+    rm -rf $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/attr
+. ./common/reflink
+
+# real QA test starts here
+_supported_os Linux
+_supported_fs xfs
+_require_scratch_reflink
+_require_scratch_nocheck
+_require_cp_reflink
+_require_test_program "punch-alternating"
+
+rm -f $seqres.full
+
+echo "Format and mount"
+_scratch_mkfs -d agcount=1 > $seqres.full 2>&1
+_scratch_mount >> $seqres.full 2>&1
+
+testdir=$SCRATCH_MNT/test-$seq
+mkdir $testdir
+
+blksz=65536
+
+echo "Create original files"
+_pwrite_byte 0x61 0 $blksz $testdir/file1 >> $seqres.full
+_cp_reflink $testdir/file1 $testdir/file2 >> $seqres.full
+
+echo "Change reference count"
+umount $SCRATCH_MNT
+echo "set refcount to -4" >> $seqres.full
+$XFS_DB_PROG -x -c 'agf 0' -c 'addr refcntroot' -c 'write recs[1].refcount 4294967292' $SCRATCH_DEV >> $seqres.full
+echo "check refcount after setting to -4" >> $seqres.full
+$XFS_DB_PROG -c 'agf 0' -c 'addr refcntroot' -c 'p recs[1]' $SCRATCH_DEV >> $seqres.full
+_scratch_mount >> $seqres.full
+
+echo "Reflink the overlinked file"
+_cp_reflink $testdir/file1 $testdir/file3 >> $seqres.full
+_cp_reflink $testdir/file1 $testdir/file4 >> $seqres.full
+_cp_reflink $testdir/file1 $testdir/file5 >> $seqres.full
+_cp_reflink $testdir/file1 $testdir/file6 >> $seqres.full
+_cp_reflink $testdir/file1 $testdir/file7 >> $seqres.full
+
+echo "Check scratch fs"
+umount $SCRATCH_MNT
+echo "check refcount after reflinking 5 more times" >> $seqres.full
+$XFS_DB_PROG -c 'agf 0' -c 'addr refcntroot' -c 'p recs[1]' $SCRATCH_DEV >> $seqres.full
+_scratch_mount >> $seqres.full
+
+echo "CoW a couple files"
+_pwrite_byte 0x62 0 $blksz $testdir/file3 >> $seqres.full
+_pwrite_byte 0x62 0 $blksz $testdir/file5 >> $seqres.full
+_pwrite_byte 0x62 0 $blksz $testdir/file7 >> $seqres.full
+
+echo "Check scratch fs"
+umount $SCRATCH_MNT
+echo "check refcount after cowing 3 files" >> $seqres.full
+$XFS_DB_PROG -c 'agf 0' -c 'addr refcntroot' -c 'p recs[1]' $SCRATCH_DEV >> $seqres.full
+_scratch_mount >> $seqres.full
+
+echo "Remove reflinked files"
+rm -rf $testdir/file*
+
+echo "Check scratch fs"
+umount $SCRATCH_MNT
+echo "check refcount after removing all files" >> $seqres.full
+$XFS_DB_PROG -c 'agf 0' -c 'addr refcntroot' -c 'p recs[1]' $SCRATCH_DEV >> $seqres.full
+$XFS_REPAIR_PROG -o force_geometry -n $SCRATCH_DEV >> $seqres.full 2>&1
+res=$?
+if [ $res -eq 0 ]; then
+	# If repair succeeds then format the device so that the post-test
+	# check doesn't fail due to the single AG.
+	_scratch_mkfs >> $seqres.full 2>&1
+else
+	_fail "xfs_repair fails"
+fi
+
+# success, all done
+status=0
+exit