[RFC,21/46] e2fsck: merge badblocks after thread finishes

diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index 56004c9b..79a9eddf 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -2283,16 +2283,19 @@  static int _e2fsck_pass1_merge_fs(ext2_filsys dest, ext2_filsys src)
 	io_channel dest_image_io;
 	ext2fs_inode_bitmap inode_map;
 	ext2fs_block_bitmap block_map;
+	ext2_badblocks_list badblocks;
 
 	dest_io = dest->io;
 	dest_image_io = dest->image_io;
 	inode_map = dest->inode_map;
 	block_map = dest->block_map;
+	badblocks = dest->badblocks;
 	memcpy(dest, src, sizeof(struct struct_ext2_filsys));
 	dest->io = dest_io;
 	dest->image_io = dest_image_io;
 	dest->inode_map = inode_map;
 	dest->block_map = block_map;
+	dest->badblocks = badblocks;
 	/*
 	 * PASS1_MERGE_FS_BITMAP might return directly from this function,
 	 * so please do NOT leave any garbage behind after returning.
@@ -2309,7 +2312,10 @@  static int _e2fsck_pass1_merge_fs(ext2_filsys dest, ext2_filsys src)
 	}
 
 	if (src->badblocks) {
-		retval = ext2fs_badblocks_copy(src->badblocks, &dest->badblocks);
+		if (dest->badblocks == NULL)
+			retval = ext2fs_badblocks_copy(src->badblocks, &dest->badblocks);
+		else
+			retval = ext2fs_badblocks_merge(src->badblocks, dest->badblocks);
 		if (retval)
 			goto out_dblist;
 	}
diff --git a/lib/ext2fs/badblocks.c b/lib/ext2fs/badblocks.c
index 0f23983b..568634ff 100644
--- a/lib/ext2fs/badblocks.c
+++ b/lib/ext2fs/badblocks.c
@@ -11,6 +11,7 @@ 
 
 #include "config.h"
 #include <stdio.h>
+#include <assert.h>
 #include <string.h>
 #if HAVE_UNISTD_H
 #include <unistd.h>
@@ -56,6 +57,65 @@  static errcode_t make_u32_list(int size, int num, __u32 *list,
 	return 0;
 }
 
+/*
+ * Merge list from src to dest
+ */
+static errcode_t merge_u32_list(ext2_u32_list src, ext2_u32_list dest)
+{
+	errcode_t	 retval;
+	int		 src_count = src->num;
+	int		 dest_count = dest->num;
+	int		 size = src->size + dest->size;
+	int		 size_entry = sizeof(blk_t);
+	blk_t		*array;
+	blk_t		*array_ptr;
+	blk_t		*src_array = src->list;
+	blk_t		*dest_array = dest->list;
+	int		 src_index = 0;
+	int		 dest_index = 0;
+
+	if (src->num == 0)
+		return 0;
+
+	retval = ext2fs_get_array(size, size_entry, &array);
+	if (retval)
+		return retval;
+
+	array_ptr = array;
+	/*
+	 * This can be improved by binary search and memcpy, but codes would
+	 * be complexer. And if number of bad blocks is small, the optimization
+	 * won't improve performance a lot.
+	 */
+	while (src_index < src_count || dest_index < dest_count) {
+		if (src_index >= src_count) {
+			memcpy(array_ptr, &dest_array[dest_index],
+			       (dest_count - dest_index) * size_entry);
+			break;
+		}
+		if (dest_index >= dest_count) {
+			memcpy(array_ptr, &src_array[src_index],
+			       (src_count - src_index) * size_entry);
+			break;
+		}
+		if (src_array[src_index] < dest_array[dest_index]) {
+			*array_ptr = src_array[src_index];
+			src_index++;
+		} else {
+			assert(src_array[src_index] > dest_array[dest_index]);
+			*array_ptr = dest_array[dest_index];
+			dest_index++;
+		}
+		array_ptr++;
+	}
+
+	ext2fs_free_mem(&dest->list);
+	dest->list = array;
+	dest->num = src_count + dest_count;
+	dest->size = size;
+	return 0;
+}
+
 
 /*
  * This procedure creates an empty u32 list.
@@ -79,13 +139,7 @@  errcode_t ext2fs_badblocks_list_create(ext2_badblocks_list *ret, int size)
  */
 errcode_t ext2fs_u32_copy(ext2_u32_list src, ext2_u32_list *dest)
 {
-	errcode_t	retval;
-
-	retval = make_u32_list(src->size, src->num, src->list, dest);
-	if (retval)
-		return retval;
-	(*dest)->badblocks_flags = src->badblocks_flags;
-	return 0;
+	return make_u32_list(src->size, src->num, src->list, dest);
 }
 
 errcode_t ext2fs_badblocks_copy(ext2_badblocks_list src,
@@ -95,6 +149,13 @@  errcode_t ext2fs_badblocks_copy(ext2_badblocks_list src,
 			       (ext2_u32_list *) dest);
 }
 
+errcode_t ext2fs_badblocks_merge(ext2_badblocks_list src,
+				 ext2_badblocks_list dest)
+{
+	return merge_u32_list((ext2_u32_list) src,
+			      (ext2_u32_list) dest);
+}
+
 /*
  * This procedure frees a badblocks list.
  *
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 2cc6d76e..1404e14a 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -814,6 +814,8 @@  extern int ext2fs_badblocks_list_iterate(ext2_badblocks_iterate iter,
 extern void ext2fs_badblocks_list_iterate_end(ext2_badblocks_iterate iter);
 extern errcode_t ext2fs_badblocks_copy(ext2_badblocks_list src,
 				       ext2_badblocks_list *dest);
+extern errcode_t ext2fs_badblocks_merge(ext2_badblocks_list src,
+					ext2_badblocks_list dest);
 extern int ext2fs_badblocks_equal(ext2_badblocks_list bb1,
 				  ext2_badblocks_list bb2);
 extern int ext2fs_u32_list_count(ext2_u32_list bb);
diff --git a/lib/ext2fs/ext2fsP.h b/lib/ext2fs/ext2fsP.h
index ad8b7d52..02df759a 100644
--- a/lib/ext2fs/ext2fsP.h
+++ b/lib/ext2fs/ext2fsP.h
@@ -34,7 +34,6 @@  struct ext2_struct_u32_list {
 	int	num;
 	int	size;
 	__u32	*list;
-	int	badblocks_flags;
 };
 
 struct ext2_struct_u32_iterate {