generic: add test for truncate/fpunch of an active swapfile

These should not be allowed.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

tests/generic/494

@@ -0,0 +1,73 @@
+#! /bin/bash
+# FS QA Test 494
+#
+# Test truncation/hole punching of an active swapfile.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2018 Facebook.  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 -f $tmp.*
+}
+
+. ./common/rc
+. ./common/filter
+
+rm -f $seqres.full
+
+_supported_fs generic
+_supported_os Linux
+_require_scratch_swapfile
+_require_xfs_io_command "fpunch"
+
+echo "Format and mount"
+_scratch_mkfs > $seqres.full 2>&1
+_scratch_mount >> $seqres.full 2>&1
+
+testdir="$SCRATCH_MNT/test-$seq"
+mkdir "$testdir"
+
+blocks=160
+blksz=65536
+
+echo "Initialize file"
+_format_swapfile "$testdir/file1" $((blocks * blksz))
+swapon "$testdir/file1"
+
+echo "Try to truncate"
+$XFS_IO_PROG -c "truncate $blksz" "$testdir/file1"
+
+echo "Try to punch hole"
+$XFS_IO_PROG -c "fpunch $blksz $((2 * blksz))" "$testdir/file1"
+
+echo "Tear it down"
+swapoff "$testdir/file1"
+
+status=0
+exit

tests/generic/494.out

@@ -0,0 +1,8 @@
+QA output created by 494
+Format and mount
+Initialize file
+Try to truncate
+ftruncate: Text file busy
+Try to punch hole
+fallocate: Text file busy
+Tear it down

tests/generic/group

@@ -495,3 +495,4 @@
 491 auto quick freeze mount
 492 auto quick
 493 auto quick swap
+494 auto quick swap