Fix handling of linked rename chains in incremental backups

* src/incremen.c: Change the meaning of the DIRF_RENAMED flag.  Now it
marks a directory which is the last one in a chain of renames.
Regular renamed directories are recognized by their orig member being
non-NULL.  Directories marked with DIRF_RENAMED start encoding of renames.
(procdir): Clear DIRF_RENAMED flag on directories which are origins for
renames.
(makedumpdir): Use the orig member to check if the directory is a
result of a rename.
(store_rename): Move the check for DIR_IS_RENAMED to the caller. Don't
clear the DIRF_RENAMED, it is not needed any more.

* tests/rename06.at: New test.
* tests/Makefile.am: Add rename06.at
* tests/testsuite.at: Likewise.

tests/Makefile.am

@@ -200,6 +200,7 @@ TESTSUITE_AT = \
  rename03.at\
  rename04.at\
  rename05.at\
+ rename06.at\
  remfiles01.at\
  remfiles02.at\
  remfiles03.at\

tests/rename06.at

@@ -0,0 +1,88 @@
+# Test suite for GNU tar.
+# Copyright 2020 Free Software Foundation, Inc.
+#
+# This file is part of GNU tar.
+#
+# GNU tar 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; either version 3 of the License, or
+# (at your option) any later version.
+#
+# GNU tar is distributed in the hope that it will 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, see <http://www.gnu.org/licenses/>.
+
+AT_SETUP([chained renames])
+AT_KEYWORDS([incremental rename06 rename])
+
+# Description: test whether chained renames are processed correctly
+# during the incremental archive creation.  Tar 1.32.90 failed to
+# encode them.
+# Reported by: Deweloper <deweloper@wp.pl>
+# References: <20200214100922.44c43334@amazur-u.kat.adbgroup.pl>,
+#   https://lists.gnu.org/archive/html/bug-tar/2020-02/msg00008.html
+
+AT_TAR_CHECK([
+AT_SORT_PREREQ
+decho Creating directory structure
+mkdir test test/d1 test/d2
+genfile --file test/d1/file1
+genfile --file test/d2/file2
+
+decho First dump
+tar -c -g 0.snar -C test -f backup0.tar .
+
+decho Altering directory structure
+genfile --file test/d2/file3
+mv test/d1 test/d3
+mv test/d2 test/d1
+
+decho Second dump
+cp 0.snar 1.snar
+tar -vc -g 1.snar -C test -f backup1.tar .
+
+mkdir test1
+
+decho First extract
+tar -C test1 -x -g /dev/null -f backup0.tar
+
+decho Second extract
+tar -C test1 -x -g /dev/null -f backup1.tar
+
+decho Resulting directory
+find test1 | sort
+],
+[0],
+[Creating directory structure
+First dump
+Altering directory structure
+Second dump
+./
+./d1/
+./d3/
+./d1/file3
+First extract
+Second extract
+Resulting directory
+test1
+test1/d1
+test1/d1/file2
+test1/d1/file3
+test1/d3
+test1/d3/file1
+],
+[Creating directory structure
+First dump
+Altering directory structure
+Second dump
+tar: ./d1: Directory has been renamed from './d2'
+tar: ./d3: Directory has been renamed from './d1'
+First extract
+Second extract
+Resulting directory
+],[],[],[gnu, oldgnu, posix])
+AT_CLEANUP

tests/testsuite.at

@@ -390,6 +390,7 @@ m4_include([rename02.at])
 m4_include([rename03.at])
 m4_include([rename04.at])
 m4_include([rename05.at])
+m4_include([rename06.at])
 m4_include([chtype.at])
 
 AT_BANNER([Ignore failing reads])