generic: test accurate shared extent reporting

Ensure that we can create a file with a single extent, reflink two
blocks out of the middle of that extent, and the resulting fiemap
reports two shared extents, instead of lazily reporting the entire
huge extent as shared.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

tests/generic/372

@@ -0,0 +1,90 @@
+#! /bin/bash
+# FS QA Test No. 372
+#
+# Check that bmap/fiemap accurately report shared extents.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2016 Oracle, Inc.  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 7 15
+
+_cleanup()
+{
+	cd /
+	rm -rf $tmp.*
+	wait
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/reflink
+
+# real QA test starts here
+_supported_os Linux
+_supported_fs generic
+_require_scratch_reflink
+_require_fiemap
+
+echo "Format and mount"
+_scratch_mkfs > $seqres.full 2>&1
+_scratch_mount >> $seqres.full 2>&1
+
+testdir=$SCRATCH_MNT/test-$seq
+mkdir $testdir
+
+blocks=5
+blksz=65536
+sz=$((blocks * blksz))
+
+echo "Create the original files"
+$XFS_IO_PROG -f -c "falloc 0 $sz" $testdir/file1 >> $seqres.full
+_pwrite_byte 0x61 0 $sz $testdir/file1 >> $seqres.full
+_scratch_cycle_mount
+
+echo "file1 extents and holes"
+_count_extents $testdir/file1
+_count_holes $testdir/file1
+
+_reflink_range $testdir/file1 $blksz $testdir/file2 $((blksz * 3)) $blksz >> $seqres.full
+_reflink_range $testdir/file1 $((blksz * 3)) $testdir/file2 $blksz $blksz >> $seqres.full
+_scratch_cycle_mount
+
+echo "Compare files"
+md5sum $testdir/file1 | _filter_scratch
+md5sum $testdir/file2 | _filter_scratch
+
+echo "file1 extents and holes"
+_count_extents $testdir/file1
+_count_holes $testdir/file1
+echo "file2 extents and holes"
+_count_extents $testdir/file2
+_count_holes $testdir/file2
+echo "file1 shared extents"
+$XFS_IO_PROG -c 'fiemap -v' $testdir/file1 | awk '{print $5}' | grep -c '0x.*[2367aAbBfF]...$'
+
+# success, all done
+status=0
+exit

tests/generic/372.out

@@ -0,0 +1,17 @@
+QA output created by 372
+Format and mount
+Create the original files
+file1 extents and holes
+1
+0
+Compare files
+17af09af790a9b4c79cddf72f6b642cb  SCRATCH_MNT/test-372/file1
+79418df9c55ab7f58781cb7b9e7d5d91  SCRATCH_MNT/test-372/file2
+file1 extents and holes
+5
+0
+file2 extents and holes
+2
+2
+file1 shared extents
+2

tests/generic/group

@@ -374,3 +374,4 @@
 369 auto quick richacl
 370 auto quick richacl
 371 auto quick enospc prealloc
+372 auto quick clone