xfs: test source CoW across mixed block types with cowextsz set

Ensure that we can CoW the source file when the source file consists
of a range of mixed block types and there's a cowextsize hint set.

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

tests/xfs/257

@@ -0,0 +1,95 @@
+#! /bin/bash
+# FS QA Test No. 257
+#
+# Ensuring that copy on write in buffered mode to the source file when the
+# CoW range covers delalloc blocks and regular shared blocks.
+#   - Set cowextsz.
+#   - Create two files.
+#   - Truncate the first file.
+#   - Write the odd blocks of the first file.
+#   - Reflink the odd blocks of the first file into the second file.
+#   - Write the even blocks of the first file.
+#   - CoW the first file across the halfway mark, starting with the
+#     regular extent.
+#   - Check that the files are now different where we say they're different.
+#
+#-----------------------------------------------------------------------
+# 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/reflink
+
+# real QA test starts here
+_supported_os Linux
+_require_scratch_reflink
+_require_xfs_io_command "falloc"
+
+rm -f $seqres.full
+
+echo "Format and mount"
+_scratch_mkfs > $seqres.full 2>&1
+_scratch_mount >> $seqres.full 2>&1
+
+testdir=$SCRATCH_MNT/test-$seq
+mkdir $testdir
+
+echo "Create the original files"
+blksz=65536
+nr=64
+filesize=$((blksz * nr))
+$XFS_IO_PROG -c "cowextsize $((blksz * 16))" $testdir >> $seqres.full
+_sweave_reflink_holes $blksz $nr $testdir/file1 $testdir/file3 >> $seqres.full
+_scratch_remount
+
+echo "Compare files"
+md5sum $testdir/file1 | _filter_scratch
+md5sum $testdir/file3 | _filter_scratch
+md5sum $testdir/file1.chk | _filter_scratch
+
+echo "CoW across the transition"
+cowoff=$((filesize / 4))
+cowsz=$((filesize / 2))
+_sweave_reflink_holes_delalloc $blksz $nr $testdir/file1 >> $seqres.full
+$XFS_IO_PROG -f -c "pwrite -S 0x63 -b $cowsz $cowoff $cowsz" $testdir/file1 >> $seqres.full
+_pwrite_byte 0x63 $cowoff $cowsz $testdir/file1.chk >> $seqres.full
+_scratch_remount
+
+echo "Compare files"
+md5sum $testdir/file1 | _filter_scratch
+md5sum $testdir/file3 | _filter_scratch
+md5sum $testdir/file1.chk | _filter_scratch
+
+# success, all done
+status=0
+exit