generic: Partial direct write test

Getting an error midway through a direct write would return an error
and the error-code is returned in the write() call. However, partial
data is over-written during the call.

This tests simulates the ENOSPC error to check for partial direct
write consistency.

[eguan: use $AWK_PROG instead of bare awk]

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

tests/generic/472

@@ -0,0 +1,96 @@
+#! /bin/bash
+# FS QA Test No. 472
+#
+# write() to a file opened with O_DIRECT with count > remaining
+# bytes. In case of a bug, the write returns ENOSPC wheras the
+# showing no data is written, but the file contents are updated.
+# Result should be the write should return remaining bytes
+# (to aligned bytes) instead of ENOSPC error.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2017, SUSE Linux Products.  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.* $testdir1
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/populate
+. ./common/filter
+. ./common/attr
+
+# real QA test starts here
+_supported_os Linux
+_require_odirect
+_require_xfs_io_command pwrite -O
+_require_scratch
+
+rm -f $seqres.full
+
+echo "Reformat with 320M size"
+sz_bytes=$((320 * 1024 * 1024))
+_scratch_mkfs_sized $sz_bytes >> $seqres.full 2>&1
+_scratch_mount >> $seqres.full 2>&1
+testdir=$SCRATCH_MNT/$seq
+mkdir $testdir
+
+# Reserve some space to remove later
+$XFS_IO_PROG -f -c "pwrite 0 2M" $testdir/reserve > /dev/null
+
+mkdir $testdir/fillspace
+echo "Fill the filesystem"
+_fill_fs $(( 1024 * 1024 * 1024 )) $testdir/fillspace 4096 0 > /dev/null 2>&1
+
+# Remove the reserve file to work on almost full filesystem
+rm $testdir/reserve
+sync
+
+# Create a file using buffered I/O which succeeds only partially
+$XFS_IO_PROG -f -c "pwrite -w -S 0xaa 0 4M" $testdir/partial
+
+# re-write using direct I/O with another pattern using one single buffer, once
+write_size=`$XFS_IO_PROG -d -c "pwrite -O -S 0xbb -V 1 -b 4M 0 4M" $testdir/partial | \
+	$AWK_PROG '/^wrote/ {split($2, bytes, "/"); print bytes[1]}'`
+if [ -z $write_size ]; then
+	write_size=0
+fi
+
+# If bug is not fixed, pwrite will return error and but still write data
+if [ $write_size -gt 0 ]; then
+	echo "pwrite wrote more than zero bytes."
+else
+	echo "pwrite wrote zero bytes"
+fi
+
+# read the partial file to check if data written is of last write
+$XFS_IO_PROG -c "pread 0 1M -v" $testdir/partial | _filter_xfs_io_unique
+
+# success, all done
+status=0
+exit

tests/generic/472.out

@@ -0,0 +1,9 @@
+QA output created by 472
+Reformat with 320M size
+Fill the filesystem
+pwrite: No space left on device
+pwrite wrote more than zero bytes.
+00000000:  bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb  ................
+*
+read 1048576/1048576 bytes at offset 0
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)

tests/generic/group

@@ -474,3 +474,4 @@
 469 auto quick
 470 auto quick dax
 471 auto quick rw
+472 auto quick rw