tests: functional: switch to rsync for directory diffs

While "diff -r" is the most straightforward way of comparing directory
trees for differences, it has two major issues:

 * File metadata is not compared, which means that subtle bugs may be
   missed even if a test is written that exercises the buggy behaviour.
 * diff(1) doesn't know how to compare special files -- it assumes they
   are always different, which means that a test using diff(1) on
   special files will always fail (resulting in such tests not being
   added).

rsync can be used in a very similar manner to diff (with the -ni flags),
but has the additional benefit of being able to detect and resolve many
more differences between directory trees. In addition, rsync has a
standard set of features and flags while diffs feature set depends on
whether you're using GNU or BSD binutils.

Note that for several of the test cases we expect that file timestamps
will not match. For example, the ctime for a file creation or modify
event is stored in the intent log but not the mtime. Thus when replaying
the log the correct ctime is set but the current mtime is used. This is
the expected behavior, so to prevent these tests from failing, there's a
replay_directory_diff function which ignores those kinds of changes.
This fix was suggested by Brian Behlendorf.

Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>

.github/workflows/build-dependencies.txt

@@ -38,6 +38,7 @@ python3-dev
 python3-packaging
 python3-setuptools
 rng-tools
+rsync
 samba
 sysstat
 uuid-dev

tests/zfs-tests/include/commands.cfg

@@ -77,6 +77,7 @@ export SYSTEM_FILES_COMMON='arp
     readlink
     rm
     rmdir
+    rsync
     scp
     script
     sed

tests/zfs-tests/include/libtest.shlib

@@ -4303,3 +4303,69 @@ function wait_for_children #children
 	done
 	return $rv
 }
+
+#
+# Compare two directory trees recursively in a manner similar to diff(1), but
+# using rsync. If there are any discrepancies, a summary of the differences are
+# output and a non-zero error is returned.
+#
+# If you're comparing a directory after a ZIL replay, you should set
+# LIBTEST_DIFF_ZIL_REPLAY=1 or use replay_directory_diff which will cause
+# directory_diff to ignore mtime changes (the ZIL replay won't fix up mtime
+# information).
+#
+function directory_diff # dir_a dir_b
+{
+	dir_a="$1"
+	dir_b="$2"
+	zil_replay="${LIBTEST_DIFF_ZIL_REPLAY:-0}"
+
+	# Run rsync with --dry-run --itemize-changes to get something akin to diff
+	# output, but rsync is far more thorough in detecting differences (diff
+	# doesn't compare file metadata, and cannot handle special files).
+	args=("-ni" "--delete")
+
+	if [ "$zil_replay" -eq 0 ]; then
+		# Like -aAHX --devices but without --times.
+		args+=("-rlpgoDHAX" "--devices")
+	else
+		# Enable every kind of copy to make sure we detect any change.
+		args+=("-aAHX" "--devices")
+	fi
+
+	# NOTE: Quite a few rsync builds do not support --crtimes which would be
+	# necessary to verify that creation times are being maintained properly. So
+	# Unfortunately because of this we cannot use it unconditionally but we can
+	# check if this rsync build supports it and use it then. This check is
+	# based on the same check in the rsync test suite (testsuite/crtimes.test).
+	#
+	# We check ctimes even with zil_replay=1 because the ZIL does store
+	# creation times.
+	if ( rsync --version | grep "[, ] crtimes" >/dev/null ); then
+		args+=("--crtimes")
+	else
+		echo "note: this rsync package does not support --crtimes"
+	fi
+
+	diff="$(rsync "${args[@]}" "$dir_a/" "$dir_b/")"
+	rv=0
+	if [ -n "$diff" ]; then
+		echo "$diff"
+		rv=1
+	fi
+	return $rv
+}
+
+#
+# Compare two directory trees recursively, without checking whether the mtimes
+# match (creation times will be checked if the available rsync binary supports
+# it). This is necessary for ZIL replay checks (because the ZIL does not
+# contain mtimes and thus after a ZIL replay, mtimes won't match).
+#
+# This is shorthand for LIBTEST_DIFF_ZIL_REPLAY=1 directory_diff <...>.
+#
+function replay_directory_diff # dir_a dir_b
+{
+	LIBTEST_DIFF_ZIL_REPLAY=1 directory_diff "$@"
+	return $?
+}

tests/zfs-tests/tests/functional/cli_root/zfs_receive/zfs_receive_010_pos.ksh

@@ -166,12 +166,12 @@ log_must zfs destroy -fr $rfs
 cat $TESTDIR/zr010p | log_must zfs receive -o origin=$fs2@s1 $rfs
 mntpnt_old=$(get_prop mountpoint $fs)
 mntpnt_new=$(get_prop mountpoint $rfs)
-log_must diff -r $mntpnt_old $mntpnt_new
+log_must directory_diff $mntpnt_old $mntpnt_new
 log_must zfs destroy -r $rfs
 
 cat $TESTDIR/zr010p2 | log_must zfs receive -o origin=$fs@s1 $rfs
 mntpnt_old=$(get_prop mountpoint $fs2)
 mntpnt_new=$(get_prop mountpoint $rfs)
-log_must diff -r $mntpnt_old $mntpnt_new
+log_must directory_diff $mntpnt_old $mntpnt_new
 
 log_pass "zfs receive of full send as clone works"

tests/zfs-tests/tests/functional/cli_root/zfs_send/zfs_send_007_pos.ksh

@@ -83,7 +83,7 @@ test_pool ()
 	cat $streamfile | log_must zfs receive $POOL/recvfs
 
 	recv_mntpnt=$(get_prop mountpoint "$POOL/recvfs")
-	log_must diff -r $mntpnt $recv_mntpnt
+	log_must directory_diff $mntpnt $recv_mntpnt
 	log_must zfs destroy -rf $POOL/fs
 	log_must zfs destroy -rf $POOL/recvfs
 }

tests/zfs-tests/tests/functional/cli_root/zfs_snapshot/zfs_snapshot_009_pos.ksh

@@ -93,7 +93,7 @@ for i in 1 2 3; do
 done
 log_note "verify snapshot contents"
 for ds in $datasets; do
-	diff -q -r /$ds /$ds/.zfs/snapshot/snap > /dev/null 2>&1
+	directory_diff /$ds /$ds/.zfs/snapshot/snap
 	if [[ $? -eq 1 ]]; then
 		log_fail "snapshot contents are different from" \
 		    "the filesystem"

tests/zfs-tests/tests/functional/cli_root/zpool_import/zpool_import_errata4.ksh

@@ -122,7 +122,7 @@ block_device_wait
 
 old_mntpnt=$(get_prop mountpoint $POOL_NAME/testfs)
 new_mntpnt=$(get_prop mountpoint $POOL_NAME/fixed/testfs)
-log_must diff -r "$old_mntpnt" "$new_mntpnt"
+log_must directory_diff "$old_mntpnt" "$new_mntpnt"
 log_must diff /dev/zvol/$POOL_NAME/testvol /dev/zvol/$POOL_NAME/fixed/testvol
 
 log_must has_ivset_guid $POOL_NAME/fixed/testfs@snap1

tests/zfs-tests/tests/functional/features/large_dnode/large_dnode_005_pos.ksh

@@ -68,7 +68,7 @@ if [[ "$dnsize" != "1K" ]]; then
 fi
 
 log_must eval "zfs recv -F $TEST_RECV_FS < $TEST_STREAMINCR"
-log_must diff -r /$TEST_SEND_FS /$TEST_RECV_FS
+log_must directory_diff /$TEST_SEND_FS /$TEST_RECV_FS
 log_must zfs umount $TEST_SEND_FS
 log_must zfs umount $TEST_RECV_FS
 

tests/zfs-tests/tests/functional/redacted_send/redacted_incrementals.ksh

@@ -51,10 +51,10 @@ log_must eval "zfs receive $POOL2/rfs <$stream"
 # Verify receipt of normal incrementals to redaction list members.
 log_must eval "zfs send -i $sendfs@snap0 $POOL/stride3@snap >$stream"
 log_must eval "zfs recv $POOL2/rstride3 <$stream"
-log_must diff -r /$POOL/stride3 /$POOL2/rstride3
+log_must directory_diff /$POOL/stride3 /$POOL2/rstride3
 log_must eval "zfs send -i $sendfs@snap0 $POOL/stride5@snap >$stream"
 log_must eval "zfs recv $POOL2/rstride5 <$stream"
-log_must diff -r /$POOL/stride5 /$POOL2/rstride5
+log_must directory_diff /$POOL/stride5 /$POOL2/rstride5
 
 # But not a normal child that we weren't redacted with respect to.
 log_must eval "zfs send -i $sendfs@snap0 $POOL/hole@snap >$stream"
@@ -73,7 +73,7 @@ log_must mount_redacted -f $POOL2/rint
 # Verify we can receive grandchildren on the child.
 log_must eval "zfs send -i $POOL/int@snap $POOL/rm@snap >$stream"
 log_must eval "zfs receive $POOL2/rrm <$stream"
-log_must diff -r /$POOL/rm /$POOL2/rrm
+log_must directory_diff /$POOL/rm /$POOL2/rrm
 
 # But not a grandchild that the received child wasn't redacted with respect to.
 log_must eval "zfs send -i $POOL/int@snap $POOL/write@snap >$stream"
@@ -92,13 +92,13 @@ log_mustnot zfs redact $POOL/int@snap book6 $POOL/hole@snap
 # Verify we can receive a full clone of the grandchild on the child.
 log_must eval "zfs send $POOL/write@snap >$stream"
 log_must eval "zfs recv -o origin=$POOL2/rint@snap $POOL2/rwrite <$stream"
-log_must diff -r /$POOL/write /$POOL2/rwrite
+log_must directory_diff /$POOL/write /$POOL2/rwrite
 
 # Along with other origins.
 log_must eval "zfs recv -o origin=$POOL2/rfs@snap0 $POOL2/rwrite1 <$stream"
-log_must diff -r /$POOL/write /$POOL2/rwrite1
+log_must directory_diff /$POOL/write /$POOL2/rwrite1
 log_must eval "zfs recv -o origin=$POOL2@init $POOL2/rwrite2 <$stream"
-log_must diff -r /$POOL/write /$POOL2/rwrite2
+log_must directory_diff /$POOL/write /$POOL2/rwrite2
 log_must zfs destroy -R $POOL2/rwrite2
 
 log_must zfs destroy -R $POOL2/rfs
@@ -140,7 +140,7 @@ unmount_redacted $POOL2/rfs
 # sending from the bookmark.
 log_must eval "zfs send -i $sendfs#book7 $POOL/hole1@snap >$stream"
 log_must eval "zfs recv $POOL2/rhole1 <$stream"
-log_must diff -r /$POOL/hole1 /$POOL2/rhole1
+log_must directory_diff /$POOL/hole1 /$POOL2/rhole1
 
 # Verify we can receive an intermediate clone redacted with respect to a
 # non-subset if we send from the bookmark.

tests/zfs-tests/tests/functional/redacted_send/redacted_largeblocks.ksh

@@ -58,6 +58,6 @@ unmount_redacted $recvfs
 log_must eval "zfs send -L -i $sendfs@snap $clone@snap1 >$stream"
 log_must stream_has_features $stream large_blocks
 log_must eval "zfs recv $recvfs/new <$stream"
-log_must diff -r $clone_mnt $recv_mnt/new
+log_must directory_diff $clone_mnt $recv_mnt/new
 
 log_pass "Large blocks and redacted send work correctly together."

tests/zfs-tests/tests/functional/rsend/recv_dedup.ksh

@@ -48,6 +48,7 @@ log_must eval "zstream redup $sendfile | zfs recv -d $TESTPOOL/recv"
 
 log_must mkdir /$TESTPOOL/tar
 log_must tar --directory /$TESTPOOL/tar -xzf $tarfile
-log_must diff -r /$TESTPOOL/tar /$TESTPOOL/recv
+# The recv'd filesystem is called "/fs", so only compare that subdirectory.
+log_must directory_diff /$TESTPOOL/tar/fs /$TESTPOOL/recv/fs
 
 log_pass "zfs can receive dedup send streams with 'zstream redup'"

tests/zfs-tests/tests/functional/rsend/rsend.kshlib

@@ -212,7 +212,7 @@ function cmp_ds_cont
 	srcdir=$(get_prop mountpoint $src_fs)
 	dstdir=$(get_prop mountpoint $dst_fs)
 
-	diff -r $srcdir $dstdir > /dev/null 2>&1
+	replay_directory_diff $srcdir $dstdir
 	return $?
 }
 
@@ -627,12 +627,12 @@ function file_check
 
 	if [[ -d /$recvfs/.zfs/snapshot/a && -d \
 	    /$sendfs/.zfs/snapshot/a ]]; then
-		diff -r /$recvfs/.zfs/snapshot/a /$sendfs/.zfs/snapshot/a
+		directory_diff /$recvfs/.zfs/snapshot/a /$sendfs/.zfs/snapshot/a
 		[[ $? -eq 0 ]] || log_fail "Differences found in snap a"
 	fi
 	if [[ -d /$recvfs/.zfs/snapshot/b && -d \
 	    /$sendfs/.zfs/snapshot/b ]]; then
-		diff -r /$recvfs/.zfs/snapshot/b /$sendfs/.zfs/snapshot/b
+		directory_diff /$recvfs/.zfs/snapshot/b /$sendfs/.zfs/snapshot/b
 		[[ $? -eq 0 ]] || log_fail "Differences found in snap b"
 	fi
 }

tests/zfs-tests/tests/functional/slog/slog_replay_fs_001.ksh

@@ -178,8 +178,8 @@ log_must rm /$TESTPOOL/$TESTFS/link_and_unlink.link
 #
 # 4. Copy TESTFS to temporary location (TESTDIR/copy)
 #
-log_must mkdir -p $TESTDIR/copy
-log_must cp -a /$TESTPOOL/$TESTFS/* $TESTDIR/copy/
+log_must mkdir -p $TESTDIR
+log_must rsync -aHAX /$TESTPOOL/$TESTFS/ $TESTDIR/copy
 
 #
 # 5. Unmount filesystem and export the pool
@@ -213,7 +213,7 @@ log_must ls_xattr /$TESTPOOL/$TESTFS/xattr.dir
 log_must ls_xattr /$TESTPOOL/$TESTFS/xattr.file
 
 log_note "Verify working set diff:"
-log_must diff -r /$TESTPOOL/$TESTFS $TESTDIR/copy
+log_must replay_directory_diff $TESTDIR/copy /$TESTPOOL/$TESTFS
 
 log_note "Verify file checksum:"
 typeset checksum1=$(sha256digest /$TESTPOOL/$TESTFS/payload)

tests/zfs-tests/tests/functional/slog/slog_replay_fs_002.ksh

@@ -98,8 +98,8 @@ log_must eval 'for i in $(seq $NFILES); do zfs set dnodesize=${dnsize[$RANDOM %
 #
 # 4. Copy TESTFS to temporary location (TESTDIR/copy)
 #
-log_must mkdir -p $TESTDIR/copy
-log_must cp -a /$TESTPOOL/$TESTFS/* $TESTDIR/copy/
+log_must mkdir -p $TESTDIR
+log_must rsync -aHAX /$TESTPOOL/$TESTFS/ $TESTDIR/copy
 
 #
 # 5. Unmount filesystem and export the pool
@@ -132,6 +132,6 @@ log_note "Verify number of files"
 log_must test "$(ls /$TESTPOOL/$TESTFS/dir0 | wc -l)" -eq $NFILES
 
 log_note "Verify working set diff:"
-log_must diff -r /$TESTPOOL/$TESTFS $TESTDIR/copy
+log_must replay_directory_diff $TESTDIR/copy /$TESTPOOL/$TESTFS
 
 log_pass "Replay of intent log succeeds."

tests/zfs-tests/tests/functional/snapshot/snapshot_002_pos.ksh

@@ -121,7 +121,7 @@ log_must tar xf $TESTDIR/tarball.snapshot.tar
 
 cd $CWD || log_fail "Could not cd $CWD"
 
-diff -q -r $TESTDIR/original $TESTDIR/snapshot > /dev/null 2>&1
+directory_diff $TESTDIR/original $TESTDIR/snapshot
 if [[ $? -eq 1 ]]; then
 	log_fail "Directory structures differ."
 fi

tests/zfs-tests/tests/functional/snapshot/snapshot_006_pos.ksh

@@ -119,7 +119,7 @@ log_must tar xf $TESTDIR1/tarball.snapshot.tar
 
 cd $CWD || log_fail "Could not cd $CWD"
 
-diff -q -r $TESTDIR1/original $TESTDIR1/snapshot > /dev/null 2>&1
+directory_diff $TESTDIR1/original $TESTDIR1/snapshot
 if [[ $? -eq 1 ]]; then
 	log_fail "Directory structures differ."
 fi