dio: unwritten conversion bug tests

Check that we don't expose old disk contents when a directio write to
an unwritten extent fails due to IO errors.  This primarily affects
XFS and ext4.

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

tests/generic/250

@@ -0,0 +1,100 @@
+#! /bin/bash
+# FS QA Test No. 250
+#
+# Create an unwritten extent, set up dm-error, try a DIO write, then
+# make sure we can't read back old disk contents.
+#
+#-----------------------------------------------------------------------
+# 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.* $testdir
+    _dmerror_cleanup
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/dmerror
+
+# real QA test starts here
+_supported_os Linux
+_require_scratch
+_require_dm_target error
+_require_xfs_io_command "falloc"
+
+rm -f $seqres.full
+
+
+echo "Format and mount"
+$XFS_IO_PROG -d -c "pwrite -S 0x69 -b 1048576 0 $((64 * 1048576))" $SCRATCH_DEV >> $seqres.full
+_scratch_mkfs_sized $((64 * 1048576)) > $seqres.full 2>&1
+_dmerror_init
+_dmerror_mount >> $seqres.full 2>&1
+_dmerror_unmount
+_dmerror_mount
+
+testdir=$SCRATCH_MNT/test-$seq
+mkdir $testdir
+
+blksz=65536
+nr=640
+bufnr=128
+filesize=$((blksz * nr))
+bufsize=$((blksz * bufnr))
+
+_require_fs_space $SCRATCH_MNT $((filesize / 1024 * 5 / 4))
+
+echo "Create the original files"
+$XFS_IO_PROG -f -c "falloc 0 $filesize" $testdir/file2 >> $seqres.full
+_dmerror_unmount
+_dmerror_mount
+
+echo "Compare files"
+md5sum $testdir/file2 | _filter_scratch
+
+echo "CoW and unmount"
+$XFS_IO_PROG -f -c "pwrite -S 0x63 $bufsize 1" $testdir/file2 >> $seqres.full
+sync
+_dmerror_load_error_table
+$XFS_IO_PROG -d -f -c "pwrite -S 0x63 -b $bufsize 0 $filesize" $testdir/file2 >> $seqres.full
+_dmerror_load_working_table
+_dmerror_unmount
+_dmerror_mount
+
+echo "Compare files"
+md5sum $testdir/file2 | _filter_scratch
+
+echo "Check for damage"
+_dmerror_unmount
+_dmerror_cleanup
+_repair_scratch_fs >> $seqres.full
+
+# success, all done
+status=0
+exit