xfs: don't allow realtime swap files

Linux swapfiles use bmap which has no ability to tell the swap code
that the blocks its reporting aren't actually on the data device.
Therefore, swapon on a realtime file could corrupt random blocks on
the data device, so we must ensure that swapon cannot happen.

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

tests/xfs/419

@@ -0,0 +1,74 @@
+#! /bin/bash
+# FS QA Test No. 419
+#
+# Check that we can't swapon a realtime file.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2017 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.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# real QA test starts here
+_supported_os Linux
+_supported_fs xfs
+_require_realtime
+_require_scratch_swapfile
+
+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"
+echo >> $seqres.full
+$XFS_IO_PROG -c "open -f -R $testdir/dummy" $testdir >> $seqres.full
+echo moo >> $testdir/dummy
+$XFS_IO_PROG -c "open -f -R $testdir/file1" $testdir >> $seqres.full
+_pwrite_byte 0x61 0 $((blocks * blksz)) $testdir/file1 >> $seqres.full
+mkswap -U 27376b42-ff65-42ca-919f-6c9b62292a5c $testdir/file1 >> $seqres.full
+
+echo "Try to swapon"
+swapon $testdir/file1 2>&1 | _filter_scratch
+
+swapoff $testdir/file1 >> $seqres.full 2>&1
+
+# success, all done
+status=0
+exit

tests/xfs/419.out

@@ -0,0 +1,5 @@
+QA output created by 419
+Format and mount
+Initialize file
+Try to swapon
+swapon: SCRATCH_MNT/test-419/file1: swapon failed: Invalid argument

tests/xfs/group

@@ -416,3 +416,4 @@
 416 dangerous_fuzzers dangerous_scrub dangerous_repair
 417 dangerous_fuzzers dangerous_scrub dangerous_online_repair
 418 dangerous_fuzzers dangerous_scrub dangerous_repair
+419 auto quick