[PATCH v2 3/9] generic: test hardlink to unlinked file

[Eryu Guan <eguan@redhat.com>]

Kernel commit

aae8a97 fs: Don't allow to create hardlink for deleted file

disabled hardlink to unlinked file.

Test the race between link and unlink, which could end up adding link
count to an unlinked file and leading to fs corruption on xfs.

Test case was originally written by Eric Sandeen.

Signed-off-by: Eryu Guan <eguan@redhat.com>
---
v2:
- create different link file in each iteration in link_unlink_storm(), which
  is confirmed to be able to reproduce the original corruption
- remove all newly created & tail'ed files at last, out of the loop, to avoid
  tail & rm race
- iterate $nr_cpu times to do the link_unlink_storm, not a fixed number
- add to quick group

 tests/generic/073     | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/generic/073.out |   2 +
 tests/generic/group   |   1 +
 3 files changed, 105 insertions(+)
 create mode 100755 tests/generic/073
 create mode 100644 tests/generic/073.out

diff --git a/tests/generic/073 b/tests/generic/073
new file mode 100755
index 0000000..6fd8c89
--- /dev/null
+++ b/tests/generic/073
@@ -0,0 +1,102 @@
+#! /bin/bash
+# FS QA Test No. 073
+#
+# Test hardlink to unlinked file.
+#
+# Regression test for commit:
+# aae8a97 fs: Don't allow to create hardlink for deleted file
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2015 Red Hat 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 15
+
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# real QA test starts here
+_supported_fs generic
+_supported_os Linux
+_require_scratch
+
+link_unlink_storm()
+{
+	local src=$1
+	local target=$2
+	local i=0
+
+	while true; do
+		ln -f $src $target.$i >/dev/null 2>&1
+		rm -f $target.$i >/dev/null 2>&1
+		let i=i+1
+	done
+}
+
+rm -f $seqres.full
+nr_cpu=`$here/src/feature -o`
+echo "Silence is golden"
+
+_scratch_mkfs >>$seqres.full 2>&1
+_scratch_mount
+
+# create, open & unlinked files so unlinked inode list is not empty
+for i in `seq 1 $nr_cpu`; do
+	testfile=$SCRATCH_MNT/$seq.unlinked.$i
+	touch $testfile
+	tail -f $testfile &
+	tail_pids="$tail_pids $!"
+done
+rm -f $SCRATCH_MNT/$seq.unlinked.*
+
+# start link/unlink storm
+src=$SCRATCH_MNT/$seq.target
+touch $src
+for i in `seq 1 $nr_cpu`; do
+	target=$SCRATCH_MNT/$seq.target.link.$i
+	link_unlink_storm $src $target &
+	link_pids="$link_pids $!"
+done
+
+# remove & re-create target to race with link/unlink
+while true; do
+	rm -f $src
+	touch $src
+done &
+sleep 5
+kill $! >/dev/null 2>&1
+
+kill $tail_pids $link_pids >/dev/null 2>&1
+wait $tail_pids $link_pids
+
+# all done, no oops/hang expected, _check_filesystems checks SCRATCH_DEV after test
+status=0
+exit
diff --git a/tests/generic/073.out b/tests/generic/073.out
new file mode 100644
index 0000000..d107704
--- /dev/null
+++ b/tests/generic/073.out
@@ -0,0 +1,2 @@
+QA output created by 073
+Silence is golden
diff --git a/tests/generic/group b/tests/generic/group
index c0210d2..ee5b642 100644
--- a/tests/generic/group
+++ b/tests/generic/group
@@ -75,6 +75,7 @@
 070 attr udf auto quick stress
 071 auto quick prealloc
 072 auto quick quota
+073 auto metadata quick
 074 rw udf auto
 075 rw udf auto quick
 076 metadata rw udf auto quick stress
-- 
2.1.0