diff --git a/lib/ext2fs/tdb.c b/lib/ext2fs/tdb.c
index 1d97685..7317288 100644
--- a/lib/ext2fs/tdb.c
+++ b/lib/ext2fs/tdb.c
@@ -4142,3 +4142,13 @@ int tdb_reopen_all(int parent_longlived)
 
 	return 0;
 }
+
+/**
+ * Flush a database file from the page cache.
+ **/
+int tdb_flush(struct tdb_context *tdb)
+{
+	if (tdb->fd != -1)
+		return fsync(tdb->fd);
+	return 0;
+}
diff --git a/lib/ext2fs/tdb.h b/lib/ext2fs/tdb.h
index 732ef0e..6a4086c 100644
--- a/lib/ext2fs/tdb.h
+++ b/lib/ext2fs/tdb.h
@@ -129,6 +129,7 @@ typedef struct TDB_DATA {
 #define tdb_lockall_nonblock ext2fs_tdb_lockall_nonblock
 #define tdb_lockall_read_nonblock ext2fs_tdb_lockall_read_nonblock
 #define tdb_lockall_unmark ext2fs_tdb_lockall_unmark
+#define tdb_flush ext2fs_tdb_flush
 
 /* this is the context structure that is returned from a db open */
 typedef struct tdb_context TDB_CONTEXT;
@@ -191,6 +192,7 @@ size_t tdb_map_size(struct tdb_context *tdb);
 int tdb_get_flags(struct tdb_context *tdb);
 void tdb_enable_seqnum(struct tdb_context *tdb);
 void tdb_increment_seqnum_nonblock(struct tdb_context *tdb);
+int tdb_flush(struct tdb_context *tdb);
 
 /* Low level locking functions: use with care */
 int tdb_chainlock(struct tdb_context *tdb, TDB_DATA key);
diff --git a/lib/ext2fs/undo_io.c b/lib/ext2fs/undo_io.c
index d6beb02..94317cb 100644
--- a/lib/ext2fs/undo_io.c
+++ b/lib/ext2fs/undo_io.c
@@ -37,6 +37,7 @@
 #if HAVE_SYS_RESOURCE_H
 #include <sys/resource.h>
 #endif
+#include <limits.h>
 
 #include "tdb.h"
 
@@ -354,8 +355,12 @@ static errcode_t undo_open(const char *name, int flags, io_channel *channel)
 		data->real = 0;
 	}
 
+	if (data->real)
+		io->flags = (io->flags & ~CHANNEL_FLAGS_DISCARD_ZEROES) |
+			    (data->real->flags & CHANNEL_FLAGS_DISCARD_ZEROES);
+
 	/* setup the tdb file */
-	data->tdb = tdb_open(tdb_file, 0, TDB_CLEAR_IF_FIRST,
+	data->tdb = tdb_open(tdb_file, 0, TDB_CLEAR_IF_FIRST | TDB_NOLOCK | TDB_NOSYNC,
 			     O_RDWR | O_CREAT | O_TRUNC | O_EXCL, 0600);
 	if (!data->tdb) {
 		retval = errno;
@@ -399,8 +404,10 @@ static errcode_t undo_close(io_channel channel)
 		return retval;
 	if (data->real)
 		retval = io_channel_close(data->real);
-	if (data->tdb)
+	if (data->tdb) {
+		tdb_flush(data->tdb);
 		tdb_close(data->tdb);
+	}
 	ext2fs_free_mem(&channel->private_data);
 	if (channel->name)
 		ext2fs_free_mem(&channel->name);
@@ -510,6 +517,77 @@ static errcode_t undo_write_byte(io_channel channel, unsigned long offset,
 	return retval;
 }
 
+static errcode_t undo_discard(io_channel channel, unsigned long long block,
+			      unsigned long long count)
+{
+	struct undo_private_data *data;
+	errcode_t	retval = 0;
+	int icount;
+
+	EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+	data = (struct undo_private_data *) channel->private_data;
+	EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+	if (count > INT_MAX)
+		return EXT2_ET_UNIMPLEMENTED;
+	icount = count;
+
+	/*
+	 * First write the existing content into database
+	 */
+	retval = undo_write_tdb(channel, block, icount);
+	if (retval)
+		return retval;
+	if (data->real)
+		retval = io_channel_discard(data->real, block, count);
+
+	return retval;
+}
+
+static errcode_t undo_zeroout(io_channel channel, unsigned long long block,
+			      unsigned long long count)
+{
+	struct undo_private_data *data;
+	errcode_t	retval = 0;
+	int icount;
+
+	EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+	data = (struct undo_private_data *) channel->private_data;
+	EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+	if (count > INT_MAX)
+		return EXT2_ET_UNIMPLEMENTED;
+	icount = count;
+
+	/*
+	 * First write the existing content into database
+	 */
+	retval = undo_write_tdb(channel, block, icount);
+	if (retval)
+		return retval;
+	if (data->real)
+		retval = io_channel_zeroout(data->real, block, count);
+
+	return retval;
+}
+
+static errcode_t undo_cache_readahead(io_channel channel,
+				      unsigned long long block,
+				      unsigned long long count)
+{
+	struct undo_private_data *data;
+	errcode_t	retval = 0;
+
+	EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
+	data = (struct undo_private_data *) channel->private_data;
+	EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
+
+	if (data->real)
+		retval = io_channel_cache_readahead(data->real, block, count);
+
+	return retval;
+}
+
 /*
  * Flush data buffers to disk.
  */
@@ -522,6 +600,8 @@ static errcode_t undo_flush(io_channel channel)
 	data = (struct undo_private_data *) channel->private_data;
 	EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
 
+	if (data->tdb)
+		tdb_flush(data->tdb);
 	if (data->real)
 		retval = io_channel_flush(data->real);
 
@@ -601,6 +681,9 @@ static struct struct_io_manager struct_undo_manager = {
 	.get_stats	= undo_get_stats,
 	.read_blk64	= undo_read_blk64,
 	.write_blk64	= undo_write_blk64,
+	.discard	= undo_discard,
+	.zeroout	= undo_zeroout,
+	.cache_readahead	= undo_cache_readahead,
 };
 
 io_manager undo_io_manager = &struct_undo_manager;
