ceph: add a new test for cross quota realms renames

For the moment cross quota realms renames has been disabled in CephFS
after a bug has been found while renaming files created and truncated.
This allowed clients to easily circumvent quotas.

Link: https://tracker.ceph.com/issues/48203
Signed-off-by: Luis Henriques <lhenriques@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

common/ceph

@@ -21,3 +21,10 @@ _ceph_create_file_layout()
 		-v "stripe_unit=$objsz stripe_count=1 object_size=$objsz" \
 		$fname
 }
+
+# this test requires to access file capabilities through vxattr 'ceph.caps'.
+_require_ceph_vxattr_caps()
+{
+	$GETFATTR_PROG -n "ceph.caps" $TEST_DIR >/dev/null 2>&1 \
+	  || _notrun "ceph.caps vxattr not supported"
+}

tests/ceph/004

@@ -0,0 +1,119 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2020 SUSE Linux Products GmbH. All Rights Reserved.
+#
+# FS QA Test 004
+#
+# Tests a bug fix found in cephfs quotas handling.  Here's a simplified testcase
+# that *should* fail:
+#
+#    mkdir files limit
+#    truncate files/file -s 10G
+#    setfattr limit -n ceph.quota.max_bytes -v 1000000
+#    mv files limit/
+#
+# Because we're creating a new file and truncating it, we have Fx caps and thus
+# the truncate operation will be cached.  This prevents the MDSs from updating
+# the quota realms and thus the client will allow the above rename(2) to happen.
+#
+# The bug resulted in dropping support for cross quota-realms renames, reverting
+# kernel commit dffdcd71458e ("ceph: allow rename operation under different
+# quota realms").
+#
+# So, the above test will now fail with a -EXDEV or, in the future (when we have
+# a proper fix), with -EDQUOT.
+#
+# This bug was tracker here:
+#
+#   https://tracker.ceph.com/issues/48203
+#
+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
+. ./common/attr
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+
+_supported_fs ceph
+_require_attrs
+_require_test
+_require_test_program "rename"
+_require_ceph_vxattr_caps # we need to get file capabilities
+
+workdir=$TEST_DIR/test-$seq
+
+orig1=$workdir/orig1
+orig2=$workdir/orig2
+file1=$orig1/file
+file2=$orig2/file
+dest=$workdir/dest
+
+rm -rf $workdir
+mkdir $workdir
+mkdir $orig1 $orig2 $dest
+
+# get only the hexadecimal value of the ceph.caps vxattr, which has the
+# following format:
+#   ceph.caps="pAsLsXsFscr/0xd55"
+get_ceph_caps()
+{
+	$GETFATTR_PROG --only-values -n "ceph.caps" $1 2>/dev/null \
+	    | cut -d / -f2
+}
+
+# check that a file has cephfs capabilities 'Fs'
+check_Fs_caps()
+{
+	caps=`get_ceph_caps $1`
+	# Fs cap is bit (1 << 8)
+	Fs=$((1 << 8))
+	res=$(($caps & $Fs))
+	if [ $res -ne $Fs ]; then
+		_fail "File $1 doesn't have Fs caps ($caps)"
+	fi
+}
+
+# set quota to 1m
+$SETFATTR_PROG -n ceph.quota.max_bytes -v 1000000 $dest
+# set quota to 20g
+$SETFATTR_PROG -n ceph.quota.max_bytes -v 20000000000 $orig2
+
+#
+# The following 2 testcases shall fail with either -EXDEV or -EDQUOT
+#
+
+# from 'root' realm to $dest realm
+$XFS_IO_PROG -f -c "truncate 10G" $file1
+check_Fs_caps $file1
+$here/src/rename $orig1 $dest/new1 >> $seqres.full 2>&1
+[ $? -ne 1 ] && _fail "cross quota realms rename succeeded"
+
+# from $orig2 realm to $dest realm
+$XFS_IO_PROG -f -c "truncate 10G" $file2
+check_Fs_caps $file2
+$here/src/rename $orig2 $dest/new2 >> $seqres.full 2>&1
+[ $? -ne 1 ] && _fail "cross quota realms rename succeeded"
+
+echo "Silence is golden"
+
+# success, all done
+status=0
+exit

tests/ceph/004.out

@@ -0,0 +1,2 @@
+QA output created by 004
+Silence is golden

tests/ceph/group

@@ -1,3 +1,4 @@
 001 auto quick copy
 002 auto quick copy
 003 auto quick copy
+004 auto quick quota