oreorebtrfsck.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <uuid/uuid.h>
#include "kerncompat.h"
#include "ctree.h"
#include "disk-io.h"
#include "volumes.h"
#include "print-tree.h"

int main()
{
	struct btrfs_root *root;
	struct btrfs_fs_info *info;
	struct extent_buffer *leaf;
	struct btrfs_item *item;
	struct btrfs_multi_bio *multi = NULL;
	struct btrfs_device *device;
	int mirror_num, num_copies;
	u64 length;


	/* problem block number */
	u64 block = 387949473792ULL;

	/* open btrfs */
	info = open_ctree_fs_info("/dev/sda2", 0, 0, 1, 1);
	root = info->fs_root;

	/* rewrite the FS :-) */
	/* write extent buffers */
	leaf = btrfs_find_create_tree_block(root, block, root->leafsize);
	mirror_num = 0;
	while(1) {
		/* read the leaf */
		btrfs_map_block(&root->fs_info->mapping_tree, READ,
				leaf->start, &length, &multi,
				mirror_num, NULL);
		device = multi->stripes[0].dev;
		leaf->fd = device->fd;
		device->total_ios++;
		leaf->dev_bytenr = multi->stripes[0].physical;
		kfree(multi);
		read_extent_from_disk(leaf, 0, leaf->len);

		/* rewrite item 6 offset */
		item = btrfs_item_nr(leaf, 6);
		btrfs_set_item_offset(leaf, item, 3703); // was 69239

		/* rewrite checksum */
		csum_tree_block(root, leaf, 0);
		
		// btrfs_print_leaf(root, leaf);

		/* write to the disk */
		write_extent_to_disk(leaf);
		fsync(leaf->fd);

		/* get number of mirrors of the leaf */
		num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
						leaf->start, leaf->len);
		if (num_copies == 1) break;
		mirror_num++;
		if (mirror_num > num_copies) break;
	}

	free_extent_buffer(leaf);

	return 0;
}