PG-1411 Make pg_resetwal work with TDE

As pg_resetwal removes old WAL segments and creates new one with empty
record we can do that write in unencrypted mode. However that requires
new WAL key creation in case if encryption was enabled before.

Author: artemgavrilov

src/bin/pg_resetwal/.gitignore

@@ -1,2 +1,5 @@
 /pg_resetwal
 /tmp_check/
+
+# Source files copied from src/backend/access/transam/
+/xlogreader.c

src/bin/pg_resetwal/Makefile

@@ -15,14 +15,29 @@ subdir = src/bin/pg_resetwal
 top_builddir = ../../..
 include $(top_builddir)/src/Makefile.global
 
+override CPPFLAGS := -DFRONTEND $(CPPFLAGS)
 LDFLAGS_INTERNAL += -L$(top_builddir)/src/fe_utils -lpgfeutils
 
 OBJS = \
 	$(WIN32RES) \
 	pg_resetwal.o
 
+ifeq ($(enable_percona_ext),yes)
+
+OBJS += \
+	$(top_srcdir)/src/fe_utils/simple_list.o \
+	$(top_builddir)/src/libtde/libtdexlog.a \
+	$(top_builddir)/src/libtde/libtde.a \
+	xlogreader.o
+
+override CPPFLAGS := -I$(top_srcdir)/contrib/pg_tde/src/include -I$(top_srcdir)/contrib/pg_tde/src/libkmip/libkmip/include $(CPPFLAGS)
+endif
+
 all: pg_resetwal
 
+xlogreader.c: % : $(top_srcdir)/src/backend/access/transam/%
+	rm -f $@ && $(LN_S) $< .
+
 pg_resetwal: $(OBJS) | submake-libpgport
 	$(CC) $(CFLAGS) $^ $(LDFLAGS) $(LDFLAGS_EX) $(LIBS) -o $@$(X)
 
@@ -36,7 +51,7 @@ uninstall:
 	rm -f '$(DESTDIR)$(bindir)/pg_resetwal$(X)'
 
 clean distclean:
-	rm -f pg_resetwal$(X) $(OBJS)
+	rm -f pg_resetwal$(X) $(OBJS) xlogreader.c
 	rm -rf tmp_check
 
 check:

src/bin/pg_resetwal/meson.build

@@ -10,10 +10,22 @@ if host_system == 'windows'
     '--FILEDESC', 'pg_resetwal - reset PostgreSQL WAL log'])
 endif
 
+link_w  = []
+include_dirs = [postgres_inc]
+
+if percona_ext == true
+  link_w = [pg_tde_frontend]
+  include_dirs = [postgres_inc, pg_tde_inc]
+  pg_resetwal_sources += xlogreader_sources
+endif
+
 pg_resetwal = executable('pg_resetwal',
   pg_resetwal_sources,
   dependencies: [frontend_code],
+  c_args: ['-DFRONTEND'], # needed for xlogreader et al
   kwargs: default_bin_args,
+  include_directories: include_dirs,
+  link_with: link_w
 )
 bin_targets += pg_resetwal
 

src/bin/pg_resetwal/pg_resetwal.c

@@ -59,6 +59,13 @@
 #include "pg_getopt.h"
 #include "storage/large_object.h"
 
+#ifdef PERCONA_EXT
+#include "pg_tde.h"
+#include "access/pg_tde_fe_init.h"
+#include "access/pg_tde_xlog_smgr.h"
+#include "access/xlog_smgr.h"
+#endif
+
 static ControlFileData ControlFile; /* pg_control values */
 static XLogSegNo newXlogSegNo;	/* new XLOG segment # */
 static bool guessed = false;	/* T if we had to guess at any values */
@@ -344,6 +351,15 @@ main(int argc, char *argv[])
 	}
 #endif
 
+#ifdef PERCONA_EXT
+	{
+		char tde_path[MAXPGPATH];
+		snprintf(tde_path, sizeof(tde_path), "%s/%s", DataDir, PG_TDE_DATA_DIR);
+		pg_tde_fe_init(tde_path);
+		TDEXLogSmgrInit();
+	}
+#endif
+
 	get_restricted_token();
 
 	/* Set mask based on PGDATA permissions */
@@ -488,6 +504,15 @@ main(int argc, char *argv[])
 		exit(1);
 	}
 
+#ifdef PERCONA_EXT
+	/*
+	 * As we always write empty record here we can do it in unencrypted mode.
+	 * We initialize writes here because new WAL key may be created in some cases,
+	 * and we want it only when we are ready to perform acutal writes.
+	 */
+	TDEXLogSmgrInitWrite(false);
+#endif
+
 	/*
 	 * Else, do the dirty deed.
 	 */
@@ -1134,14 +1159,25 @@ WriteEmptyXLOG(void)
 		pg_fatal("could not open file \"%s\": %m", path);
 
 	errno = 0;
+#ifdef PERCONA_EXT
+	if (xlog_smgr->seg_write(fd, buffer.data, XLOG_BLCKSZ, 0,
+						 ControlFile.checkPointCopy.ThisTimeLineID,
+						 newXlogSegNo, WalSegSz) != XLOG_BLCKSZ)
+#else
 	if (write(fd, buffer.data, XLOG_BLCKSZ) != XLOG_BLCKSZ)
+#endif
 	{
 		/* if write didn't set errno, assume problem is no disk space */
 		if (errno == 0)
 			errno = ENOSPC;
 		pg_fatal("could not write file \"%s\": %m", path);
 	}
 
+#ifdef PERCONA_EXT
+	/* If we used xlog smgr, we need to update the file offset */
+	lseek(fd, XLOG_BLCKSZ, SEEK_CUR);
+#endif
+
 	/* Fill the rest of the file with zeroes */
 	memset(buffer.data, 0, XLOG_BLCKSZ);
 	for (nbytes = XLOG_BLCKSZ; nbytes < WalSegSz; nbytes += XLOG_BLCKSZ)