check-integrity.c

	if (0 == sf->hdr->level) {
		struct btrfs_leaf *const leafhdr =
		    (struct btrfs_leaf *)sf->hdr;

		if (-1 == sf->i) {
			sf->nr = le32_to_cpu(leafhdr->header.nritems);

			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
				printk(KERN_INFO
				       "leaf %llu items %d generation %llu"
				       " owner %llu\n",
				       (unsigned long long)
				       sf->block_ctx->start,
				       sf->nr,
				       (unsigned long long)
				       le64_to_cpu(leafhdr->header.generation),
				       (unsigned long long)
				       le64_to_cpu(leafhdr->header.owner));
		}

continue_with_current_leaf_stack_frame:
		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
			sf->i++;
			sf->num_copies = 0;
		}

		if (sf->i < sf->nr) {
			struct btrfs_item disk_item;
			u32 disk_item_offset =
				(uintptr_t)(leafhdr->items + sf->i) -
				(uintptr_t)leafhdr;
			struct btrfs_disk_key *disk_key;
			u8 type;
			u32 item_offset;
			u32 item_size;

			if (disk_item_offset + sizeof(struct btrfs_item) >
			    sf->block_ctx->len) {
leaf_item_out_of_bounce_error:
				printk(KERN_INFO
				       "btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
				       sf->block_ctx->start,
				       sf->block_ctx->dev->name);
				goto one_stack_frame_backwards;
			}
			btrfsic_read_from_block_data(sf->block_ctx,
						     &disk_item,
						     disk_item_offset,
						     sizeof(struct btrfs_item));
			item_offset = le32_to_cpu(disk_item.offset);
			item_size = le32_to_cpu(disk_item.size);
			disk_key = &disk_item.key;
			type = disk_key->type;

			if (BTRFS_ROOT_ITEM_KEY == type) {
				struct btrfs_root_item root_item;
				u32 root_item_offset;
				u64 next_bytenr;

				root_item_offset = item_offset +
					offsetof(struct btrfs_leaf, items);
				if (root_item_offset + item_size >
				    sf->block_ctx->len)
					goto leaf_item_out_of_bounce_error;
				btrfsic_read_from_block_data(
					sf->block_ctx, &root_item,
					root_item_offset,
					item_size);
				next_bytenr = le64_to_cpu(root_item.bytenr);

				sf->error =
				    btrfsic_create_link_to_next_block(
						state,
						sf->block,
						sf->block_ctx,
						next_bytenr,
						sf->limit_nesting,
						&sf->next_block_ctx,
						&sf->next_block,
						force_iodone_flag,
						&sf->num_copies,
						&sf->mirror_num,
						disk_key,
						le64_to_cpu(root_item.
						generation));
				if (sf->error)
					goto one_stack_frame_backwards;

				if (NULL != sf->next_block) {
					struct btrfs_header *const next_hdr =
					    (struct btrfs_header *)
					    sf->next_block_ctx.datav[0];

					next_stack =
					    btrfsic_stack_frame_alloc();
					if (NULL == next_stack) {
						btrfsic_release_block_ctx(
								&sf->
								next_block_ctx);
						goto one_stack_frame_backwards;
					}

					next_stack->i = -1;
					next_stack->block = sf->next_block;
					next_stack->block_ctx =
					    &sf->next_block_ctx;
					next_stack->next_block = NULL;
					next_stack->hdr = next_hdr;
					next_stack->limit_nesting =
					    sf->limit_nesting - 1;
					next_stack->prev = sf;
					sf = next_stack;
					goto continue_with_new_stack_frame;
				}
			} else if (BTRFS_EXTENT_DATA_KEY == type &&
				   state->include_extent_data) {
				sf->error = btrfsic_handle_extent_data(
						state,
						sf->block,
						sf->block_ctx,
						item_offset,
						force_iodone_flag);
				if (sf->error)
					goto one_stack_frame_backwards;
			}

			goto continue_with_current_leaf_stack_frame;
		}
	} else {
		struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;

		if (-1 == sf->i) {
			sf->nr = le32_to_cpu(nodehdr->header.nritems);

			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
				printk(KERN_INFO "node %llu level %d items %d"
				       " generation %llu owner %llu\n",
				       (unsigned long long)
				       sf->block_ctx->start,
				       nodehdr->header.level, sf->nr,
				       (unsigned long long)
				       le64_to_cpu(nodehdr->header.generation),
				       (unsigned long long)
				       le64_to_cpu(nodehdr->header.owner));
		}

continue_with_current_node_stack_frame:
		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
			sf->i++;
			sf->num_copies = 0;
		}

		if (sf->i < sf->nr) {
			struct btrfs_key_ptr key_ptr;
			u32 key_ptr_offset;
			u64 next_bytenr;

			key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
					  (uintptr_t)nodehdr;
			if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
			    sf->block_ctx->len) {
				printk(KERN_INFO
				       "btrfsic: node item out of bounce at logical %llu, dev %s\n",
				       sf->block_ctx->start,
				       sf->block_ctx->dev->name);
				goto one_stack_frame_backwards;
			}
			btrfsic_read_from_block_data(
				sf->block_ctx, &key_ptr, key_ptr_offset,
				sizeof(struct btrfs_key_ptr));
			next_bytenr = le64_to_cpu(key_ptr.blockptr);

			sf->error = btrfsic_create_link_to_next_block(
					state,
					sf->block,
					sf->block_ctx,
					next_bytenr,
					sf->limit_nesting,
					&sf->next_block_ctx,
					&sf->next_block,
					force_iodone_flag,
					&sf->num_copies,
					&sf->mirror_num,
					&key_ptr.key,
					le64_to_cpu(key_ptr.generation));
			if (sf->error)
				goto one_stack_frame_backwards;

			if (NULL != sf->next_block) {
				struct btrfs_header *const next_hdr =
				    (struct btrfs_header *)
				    sf->next_block_ctx.datav[0];

				next_stack = btrfsic_stack_frame_alloc();
				if (NULL == next_stack)
					goto one_stack_frame_backwards;

				next_stack->i = -1;
				next_stack->block = sf->next_block;
				next_stack->block_ctx = &sf->next_block_ctx;
				next_stack->next_block = NULL;
				next_stack->hdr = next_hdr;
				next_stack->limit_nesting =
				    sf->limit_nesting - 1;
				next_stack->prev = sf;
				sf = next_stack;
				goto continue_with_new_stack_frame;
			}

			goto continue_with_current_node_stack_frame;
		}
	}

one_stack_frame_backwards:
	if (NULL != sf->prev) {
		struct btrfsic_stack_frame *const prev = sf->prev;

		/* the one for the initial block is freed in the caller */
		btrfsic_release_block_ctx(sf->block_ctx);

		if (sf->error) {
			prev->error = sf->error;
			btrfsic_stack_frame_free(sf);
			sf = prev;
			goto one_stack_frame_backwards;
		}

		btrfsic_stack_frame_free(sf);
		sf = prev;
		goto continue_with_new_stack_frame;
	} else {
		BUG_ON(&initial_stack_frame != sf);
	}

	return sf->error;
}

static void btrfsic_read_from_block_data(
	struct btrfsic_block_data_ctx *block_ctx,
	void *dstv, u32 offset, size_t len)
{
	size_t cur;
	size_t offset_in_page;
	char *kaddr;
	char *dst = (char *)dstv;
	size_t start_offset = block_ctx->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long i = (start_offset + offset) >> PAGE_CACHE_SHIFT;

	WARN_ON(offset + len > block_ctx->len);
	offset_in_page = (start_offset + offset) &
			 ((unsigned long)PAGE_CACHE_SIZE - 1);

	while (len > 0) {
		cur = min(len, ((size_t)PAGE_CACHE_SIZE - offset_in_page));
		BUG_ON(i >= (block_ctx->len + PAGE_CACHE_SIZE - 1) >>
			    PAGE_CACHE_SHIFT);
		kaddr = block_ctx->datav[i];
		memcpy(dst, kaddr + offset_in_page, cur);

		dst += cur;
		len -= cur;
		offset_in_page = 0;
		i++;
	}
}

static int btrfsic_create_link_to_next_block(
		struct btrfsic_state *state,
		struct btrfsic_block *block,
		struct btrfsic_block_data_ctx *block_ctx,
		u64 next_bytenr,
		int limit_nesting,
		struct btrfsic_block_data_ctx *next_block_ctx,
		struct btrfsic_block **next_blockp,
		int force_iodone_flag,
		int *num_copiesp, int *mirror_nump,
		struct btrfs_disk_key *disk_key,
		u64 parent_generation)
{
	struct btrfsic_block *next_block = NULL;
	int ret;
	struct btrfsic_block_link *l;
	int did_alloc_block_link;
	int block_was_created;

	*next_blockp = NULL;
	if (0 == *num_copiesp) {
		*num_copiesp =
		    btrfs_num_copies(state->root->fs_info,
				     next_bytenr, state->metablock_size);
		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
			       (unsigned long long)next_bytenr, *num_copiesp);
		*mirror_nump = 1;
	}

	if (*mirror_nump > *num_copiesp)
		return 0;

	if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
		printk(KERN_INFO
		       "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
		       *mirror_nump);
	ret = btrfsic_map_block(state, next_bytenr,
				state->metablock_size,
				next_block_ctx, *mirror_nump);
	if (ret) {
		printk(KERN_INFO
		       "btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
		       (unsigned long long)next_bytenr, *mirror_nump);
		btrfsic_release_block_ctx(next_block_ctx);
		*next_blockp = NULL;
		return -1;
	}

	next_block = btrfsic_block_lookup_or_add(state,
						 next_block_ctx, "referenced ",
						 1, force_iodone_flag,
						 !force_iodone_flag,
						 *mirror_nump,
						 &block_was_created);
	if (NULL == next_block) {
		btrfsic_release_block_ctx(next_block_ctx);
		*next_blockp = NULL;
		return -1;
	}
	if (block_was_created) {
		l = NULL;
		next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
	} else {
		if (next_block->logical_bytenr != next_bytenr &&
		    !(!next_block->is_metadata &&
		      0 == next_block->logical_bytenr)) {
			printk(KERN_INFO
			       "Referenced block @%llu (%s/%llu/%d)"
			       " found in hash table, %c,"
			       " bytenr mismatch (!= stored %llu).\n",
			       (unsigned long long)next_bytenr,
			       next_block_ctx->dev->name,
			       (unsigned long long)next_block_ctx->dev_bytenr,
			       *mirror_nump,
			       btrfsic_get_block_type(state, next_block),
			       (unsigned long long)next_block->logical_bytenr);
		} else if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
			printk(KERN_INFO
			       "Referenced block @%llu (%s/%llu/%d)"
			       " found in hash table, %c.\n",
			       (unsigned long long)next_bytenr,
			       next_block_ctx->dev->name,
			       (unsigned long long)next_block_ctx->dev_bytenr,
			       *mirror_nump,
			       btrfsic_get_block_type(state, next_block));
		next_block->logical_bytenr = next_bytenr;

		next_block->mirror_num = *mirror_nump;
		l = btrfsic_block_link_hashtable_lookup(
				next_block_ctx->dev->bdev,
				next_block_ctx->dev_bytenr,
				block_ctx->dev->bdev,
				block_ctx->dev_bytenr,
				&state->block_link_hashtable);
	}

	next_block->disk_key = *disk_key;
	if (NULL == l) {
		l = btrfsic_block_link_alloc();
		if (NULL == l) {
			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
			btrfsic_release_block_ctx(next_block_ctx);
			*next_blockp = NULL;
			return -1;
		}

		did_alloc_block_link = 1;
		l->block_ref_to = next_block;
		l->block_ref_from = block;
		l->ref_cnt = 1;
		l->parent_generation = parent_generation;

		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
			btrfsic_print_add_link(state, l);

		list_add(&l->node_ref_to, &block->ref_to_list);
		list_add(&l->node_ref_from, &next_block->ref_from_list);

		btrfsic_block_link_hashtable_add(l,
						 &state->block_link_hashtable);
	} else {
		did_alloc_block_link = 0;
		if (0 == limit_nesting) {
			l->ref_cnt++;
			l->parent_generation = parent_generation;
			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
				btrfsic_print_add_link(state, l);
		}
	}

	if (limit_nesting > 0 && did_alloc_block_link) {
		ret = btrfsic_read_block(state, next_block_ctx);
		if (ret < (int)next_block_ctx->len) {
			printk(KERN_INFO
			       "btrfsic: read block @logical %llu failed!\n",
			       (unsigned long long)next_bytenr);
			btrfsic_release_block_ctx(next_block_ctx);
			*next_blockp = NULL;
			return -1;
		}

		*next_blockp = next_block;
	} else {
		*next_blockp = NULL;
	}
	(*mirror_nump)++;

	return 0;
}

static int btrfsic_handle_extent_data(
		struct btrfsic_state *state,
		struct btrfsic_block *block,
		struct btrfsic_block_data_ctx *block_ctx,
		u32 item_offset, int force_iodone_flag)
{
	int ret;
	struct btrfs_file_extent_item file_extent_item;
	u64 file_extent_item_offset;
	u64 next_bytenr;
	u64 num_bytes;
	u64 generation;
	struct btrfsic_block_link *l;

	file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
				  item_offset;
	if (file_extent_item_offset +
	    offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
	    block_ctx->len) {
		printk(KERN_INFO
		       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
		       block_ctx->start, block_ctx->dev->name);
		return -1;
	}

	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
		file_extent_item_offset,
		offsetof(struct btrfs_file_extent_item, disk_num_bytes));
	if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
	    ((u64)0) == le64_to_cpu(file_extent_item.disk_bytenr)) {
		if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
			printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu\n",
			       file_extent_item.type,
			       (unsigned long long)
			       le64_to_cpu(file_extent_item.disk_bytenr));
		return 0;
	}

	if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
	    block_ctx->len) {
		printk(KERN_INFO
		       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
		       block_ctx->start, block_ctx->dev->name);
		return -1;
	}
	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
				     file_extent_item_offset,
				     sizeof(struct btrfs_file_extent_item));
	next_bytenr = le64_to_cpu(file_extent_item.disk_bytenr) +
		      le64_to_cpu(file_extent_item.offset);
	generation = le64_to_cpu(file_extent_item.generation);
	num_bytes = le64_to_cpu(file_extent_item.num_bytes);
	generation = le64_to_cpu(file_extent_item.generation);

	if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
		printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
		       " offset = %llu, num_bytes = %llu\n",
		       file_extent_item.type,
		       (unsigned long long)
		       le64_to_cpu(file_extent_item.disk_bytenr),
		       (unsigned long long)le64_to_cpu(file_extent_item.offset),
		       (unsigned long long)num_bytes);
	while (num_bytes > 0) {
		u32 chunk_len;
		int num_copies;
		int mirror_num;

		if (num_bytes > state->datablock_size)
			chunk_len = state->datablock_size;
		else
			chunk_len = num_bytes;

		num_copies =
		    btrfs_num_copies(state->root->fs_info,
				     next_bytenr, state->datablock_size);
		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
			       (unsigned long long)next_bytenr, num_copies);
		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
			struct btrfsic_block_data_ctx next_block_ctx;
			struct btrfsic_block *next_block;
			int block_was_created;

			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
				printk(KERN_INFO "btrfsic_handle_extent_data("
				       "mirror_num=%d)\n", mirror_num);
			if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
				printk(KERN_INFO
				       "\tdisk_bytenr = %llu, num_bytes %u\n",
				       (unsigned long long)next_bytenr,
				       chunk_len);
			ret = btrfsic_map_block(state, next_bytenr,
						chunk_len, &next_block_ctx,
						mirror_num);
			if (ret) {
				printk(KERN_INFO
				       "btrfsic: btrfsic_map_block(@%llu,"
				       " mirror=%d) failed!\n",
				       (unsigned long long)next_bytenr,
				       mirror_num);
				return -1;
			}

			next_block = btrfsic_block_lookup_or_add(
					state,
					&next_block_ctx,
					"referenced ",
					0,
					force_iodone_flag,
					!force_iodone_flag,
					mirror_num,
					&block_was_created);
			if (NULL == next_block) {
				printk(KERN_INFO
				       "btrfsic: error, kmalloc failed!\n");
				btrfsic_release_block_ctx(&next_block_ctx);
				return -1;
			}
			if (!block_was_created) {
				if (next_block->logical_bytenr != next_bytenr &&
				    !(!next_block->is_metadata &&
				      0 == next_block->logical_bytenr)) {
					printk(KERN_INFO
					       "Referenced block"
					       " @%llu (%s/%llu/%d)"
					       " found in hash table, D,"
					       " bytenr mismatch"
					       " (!= stored %llu).\n",
					       (unsigned long long)next_bytenr,
					       next_block_ctx.dev->name,
					       (unsigned long long)
					       next_block_ctx.dev_bytenr,
					       mirror_num,
					       (unsigned long long)
					       next_block->logical_bytenr);
				}
				next_block->logical_bytenr = next_bytenr;
				next_block->mirror_num = mirror_num;
			}

			l = btrfsic_block_link_lookup_or_add(state,
							     &next_block_ctx,
							     next_block, block,
							     generation);
			btrfsic_release_block_ctx(&next_block_ctx);
			if (NULL == l)
				return -1;
		}

		next_bytenr += chunk_len;
		num_bytes -= chunk_len;
	}

	return 0;
}

static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
			     struct btrfsic_block_data_ctx *block_ctx_out,
			     int mirror_num)
{
	int ret;
	u64 length;
	struct btrfs_bio *multi = NULL;
	struct btrfs_device *device;

	length = len;
	ret = btrfs_map_block(state->root->fs_info, READ,
			      bytenr, &length, &multi, mirror_num);

	if (ret) {
		block_ctx_out->start = 0;
		block_ctx_out->dev_bytenr = 0;
		block_ctx_out->len = 0;
		block_ctx_out->dev = NULL;
		block_ctx_out->datav = NULL;
		block_ctx_out->pagev = NULL;
		block_ctx_out->mem_to_free = NULL;

		return ret;
	}

	device = multi->stripes[0].dev;
	block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
	block_ctx_out->dev_bytenr = multi->stripes[0].physical;
	block_ctx_out->start = bytenr;
	block_ctx_out->len = len;
	block_ctx_out->datav = NULL;
	block_ctx_out->pagev = NULL;
	block_ctx_out->mem_to_free = NULL;

	kfree(multi);
	if (NULL == block_ctx_out->dev) {
		ret = -ENXIO;
		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#1)!\n");
	}

	return ret;
}

static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
				  u32 len, struct block_device *bdev,
				  struct btrfsic_block_data_ctx *block_ctx_out)
{
	block_ctx_out->dev = btrfsic_dev_state_lookup(bdev);
	block_ctx_out->dev_bytenr = bytenr;
	block_ctx_out->start = bytenr;
	block_ctx_out->len = len;
	block_ctx_out->datav = NULL;
	block_ctx_out->pagev = NULL;
	block_ctx_out->mem_to_free = NULL;
	if (NULL != block_ctx_out->dev) {
		return 0;
	} else {
		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#2)!\n");
		return -ENXIO;
	}
}

static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
{
	if (block_ctx->mem_to_free) {
		unsigned int num_pages;

		BUG_ON(!block_ctx->datav);
		BUG_ON(!block_ctx->pagev);
		num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
			    PAGE_CACHE_SHIFT;
		while (num_pages > 0) {
			num_pages--;
			if (block_ctx->datav[num_pages]) {
				kunmap(block_ctx->pagev[num_pages]);
				block_ctx->datav[num_pages] = NULL;
			}
			if (block_ctx->pagev[num_pages]) {
				__free_page(block_ctx->pagev[num_pages]);
				block_ctx->pagev[num_pages] = NULL;
			}
		}

		kfree(block_ctx->mem_to_free);
		block_ctx->mem_to_free = NULL;
		block_ctx->pagev = NULL;
		block_ctx->datav = NULL;
	}
}

static int btrfsic_read_block(struct btrfsic_state *state,
			      struct btrfsic_block_data_ctx *block_ctx)
{
	unsigned int num_pages;
	unsigned int i;
	u64 dev_bytenr;
	int ret;

	BUG_ON(block_ctx->datav);
	BUG_ON(block_ctx->pagev);
	BUG_ON(block_ctx->mem_to_free);
	if (block_ctx->dev_bytenr & ((u64)PAGE_CACHE_SIZE - 1)) {
		printk(KERN_INFO
		       "btrfsic: read_block() with unaligned bytenr %llu\n",
		       (unsigned long long)block_ctx->dev_bytenr);
		return -1;
	}

	num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
		    PAGE_CACHE_SHIFT;
	block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
					  sizeof(*block_ctx->pagev)) *
					 num_pages, GFP_NOFS);
	if (!block_ctx->mem_to_free)
		return -1;
	block_ctx->datav = block_ctx->mem_to_free;
	block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
	for (i = 0; i < num_pages; i++) {
		block_ctx->pagev[i] = alloc_page(GFP_NOFS);
		if (!block_ctx->pagev[i])
			return -1;
	}

	dev_bytenr = block_ctx->dev_bytenr;
	for (i = 0; i < num_pages;) {
		struct bio *bio;
		unsigned int j;
		DECLARE_COMPLETION_ONSTACK(complete);

		bio = bio_alloc(GFP_NOFS, num_pages - i);
		if (!bio) {
			printk(KERN_INFO
			       "btrfsic: bio_alloc() for %u pages failed!\n",
			       num_pages - i);
			return -1;
		}
		bio->bi_bdev = block_ctx->dev->bdev;
		bio->bi_sector = dev_bytenr >> 9;
		bio->bi_end_io = btrfsic_complete_bio_end_io;
		bio->bi_private = &complete;

		for (j = i; j < num_pages; j++) {
			ret = bio_add_page(bio, block_ctx->pagev[j],
					   PAGE_CACHE_SIZE, 0);
			if (PAGE_CACHE_SIZE != ret)
				break;
		}
		if (j == i) {
			printk(KERN_INFO
			       "btrfsic: error, failed to add a single page!\n");
			return -1;
		}
		submit_bio(READ, bio);

		/* this will also unplug the queue */
		wait_for_completion(&complete);

		if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
			printk(KERN_INFO
			       "btrfsic: read error at logical %llu dev %s!\n",
			       block_ctx->start, block_ctx->dev->name);
			bio_put(bio);
			return -1;
		}
		bio_put(bio);
		dev_bytenr += (j - i) * PAGE_CACHE_SIZE;
		i = j;
	}
	for (i = 0; i < num_pages; i++) {
		block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
		if (!block_ctx->datav[i]) {
			printk(KERN_INFO "btrfsic: kmap() failed (dev %s)!\n",
			       block_ctx->dev->name);
			return -1;
		}
	}

	return block_ctx->len;
}

static void btrfsic_complete_bio_end_io(struct bio *bio, int err)
{
	complete((struct completion *)bio->bi_private);
}

static void btrfsic_dump_database(struct btrfsic_state *state)
{
	struct list_head *elem_all;

	BUG_ON(NULL == state);

	printk(KERN_INFO "all_blocks_list:\n");
	list_for_each(elem_all, &state->all_blocks_list) {
		const struct btrfsic_block *const b_all =
		    list_entry(elem_all, struct btrfsic_block,
			       all_blocks_node);
		struct list_head *elem_ref_to;
		struct list_head *elem_ref_from;

		printk(KERN_INFO "%c-block @%llu (%s/%llu/%d)\n",
		       btrfsic_get_block_type(state, b_all),
		       (unsigned long long)b_all->logical_bytenr,
		       b_all->dev_state->name,
		       (unsigned long long)b_all->dev_bytenr,
		       b_all->mirror_num);

		list_for_each(elem_ref_to, &b_all->ref_to_list) {
			const struct btrfsic_block_link *const l =
			    list_entry(elem_ref_to,
				       struct btrfsic_block_link,
				       node_ref_to);

			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
			       " refers %u* to"
			       " %c @%llu (%s/%llu/%d)\n",
			       btrfsic_get_block_type(state, b_all),
			       (unsigned long long)b_all->logical_bytenr,
			       b_all->dev_state->name,
			       (unsigned long long)b_all->dev_bytenr,
			       b_all->mirror_num,
			       l->ref_cnt,
			       btrfsic_get_block_type(state, l->block_ref_to),
			       (unsigned long long)
			       l->block_ref_to->logical_bytenr,
			       l->block_ref_to->dev_state->name,
			       (unsigned long long)l->block_ref_to->dev_bytenr,
			       l->block_ref_to->mirror_num);
		}

		list_for_each(elem_ref_from, &b_all->ref_from_list) {
			const struct btrfsic_block_link *const l =
			    list_entry(elem_ref_from,
				       struct btrfsic_block_link,
				       node_ref_from);

			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
			       " is ref %u* from"
			       " %c @%llu (%s/%llu/%d)\n",
			       btrfsic_get_block_type(state, b_all),
			       (unsigned long long)b_all->logical_bytenr,
			       b_all->dev_state->name,
			       (unsigned long long)b_all->dev_bytenr,
			       b_all->mirror_num,
			       l->ref_cnt,
			       btrfsic_get_block_type(state, l->block_ref_from),
			       (unsigned long long)
			       l->block_ref_from->logical_bytenr,
			       l->block_ref_from->dev_state->name,
			       (unsigned long long)
			       l->block_ref_from->dev_bytenr,
			       l->block_ref_from->mirror_num);
		}

		printk(KERN_INFO "\n");
	}
}

/*
 * Test whether the disk block contains a tree block (leaf or node)
 * (note that this test fails for the super block)
 */
static int btrfsic_test_for_metadata(struct btrfsic_state *state,
				     char **datav, unsigned int num_pages)
{
	struct btrfs_header *h;
	u8 csum[BTRFS_CSUM_SIZE];
	u32 crc = ~(u32)0;
	unsigned int i;

	if (num_pages * PAGE_CACHE_SIZE < state->metablock_size)
		return 1; /* not metadata */
	num_pages = state->metablock_size >> PAGE_CACHE_SHIFT;
	h = (struct btrfs_header *)datav[0];

	if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
		return 1;

	for (i = 0; i < num_pages; i++) {
		u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
		size_t sublen = i ? PAGE_CACHE_SIZE :
				    (PAGE_CACHE_SIZE - BTRFS_CSUM_SIZE);

		crc = crc32c(crc, data, sublen);
	}
	btrfs_csum_final(crc, csum);
	if (memcmp(csum, h->csum, state->csum_size))
		return 1;

	return 0; /* is metadata */
}

static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
					  u64 dev_bytenr, char **mapped_datav,
					  unsigned int num_pages,
					  struct bio *bio, int *bio_is_patched,
					  struct buffer_head *bh,
					  int submit_bio_bh_rw)
{
	int is_metadata;
	struct btrfsic_block *block;
	struct btrfsic_block_data_ctx block_ctx;
	int ret;
	struct btrfsic_state *state = dev_state->state;
	struct block_device *bdev = dev_state->bdev;
	unsigned int processed_len;

	if (NULL != bio_is_patched)
		*bio_is_patched = 0;

again:
	if (num_pages == 0)
		return;

	processed_len = 0;
	is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
						      num_pages));

	block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
					       &state->block_hashtable);
	if (NULL != block) {
		u64 bytenr = 0;
		struct list_head *elem_ref_to;
		struct list_head *tmp_ref_to;

		if (block->is_superblock) {
			bytenr = le64_to_cpu(((struct btrfs_super_block *)
					      mapped_datav[0])->bytenr);
			if (num_pages * PAGE_CACHE_SIZE <
			    BTRFS_SUPER_INFO_SIZE) {
				printk(KERN_INFO
				       "btrfsic: cannot work with too short bios!\n");
				return;
			}
			is_metadata = 1;
			BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_CACHE_SIZE - 1));
			processed_len = BTRFS_SUPER_INFO_SIZE;
			if (state->print_mask &
			    BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
				printk(KERN_INFO
				       "[before new superblock is written]:\n");
				btrfsic_dump_tree_sub(state, block, 0);
			}
		}
		if (is_metadata) {
			if (!block->is_superblock) {
				if (num_pages * PAGE_CACHE_SIZE <
				    state->metablock_size) {
					printk(KERN_INFO
					       "btrfsic: cannot work with too short bios!\n");
					return;
				}
				processed_len = state->metablock_size;
				bytenr = le64_to_cpu(((struct btrfs_header *)
						      mapped_datav[0])->bytenr);
				btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
							       dev_state,
							       dev_bytenr);
			}
			if (block->logical_bytenr != bytenr) {
				printk(KERN_INFO
				       "Written block @%llu (%s/%llu/%d)"
				       " found in hash table, %c,"
				       " bytenr mismatch"
				       " (!= stored %llu).\n",
				       (unsigned long long)bytenr,
				       dev_state->name,
				       (unsigned long long)dev_bytenr,
				       block->mirror_num,
				       btrfsic_get_block_type(state, block),
				       (unsigned long long)
				       block->logical_bytenr);
				block->logical_bytenr = bytenr;
			} else if (state->print_mask &
				   BTRFSIC_PRINT_MASK_VERBOSE)
				printk(KERN_INFO
				       "Written block @%llu (%s/%llu/%d)"
				       " found in hash table, %c.\n",
				       (unsigned long long)bytenr,
				       dev_state->name,
				       (unsigned long long)dev_bytenr,
				       block->mirror_num,
				       btrfsic_get_block_type(state, block));
		} else {
			if (num_pages * PAGE_CACHE_SIZE <
			    state->datablock_size) {
				printk(KERN_INFO
				       "btrfsic: cannot work with too short bios!\n");
				return;
			}
			processed_len = state->datablock_size;
			bytenr = block->logical_bytenr;
			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
				printk(KERN_INFO
				       "Written block @%llu (%s/%llu/%d)"
				       " found in hash table, %c.\n",
				       (unsigned long long)bytenr,
				       dev_state->name,
				       (unsigned long long)dev_bytenr,
				       block->mirror_num,
				       btrfsic_get_block_type(state, block));
		}

		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
			printk(KERN_INFO
			       "ref_to_list: %cE, ref_from_list: %cE\n",
			       list_empty(&block->ref_to_list) ? ' ' : '!',
			       list_empty(&block->ref_from_list) ? ' ' : '!');
		if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
			printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
			       " @%llu (%s/%llu/%d), old(gen=%llu,"
			       " objectid=%llu, type=%d, offset=%llu),"
			       " new(gen=%llu),"
			       " which is referenced by most recent superblock"
			       " (superblockgen=%llu)!\n",
			       btrfsic_get_block_type(state, block),
			       (unsigned long long)bytenr,
			       dev_state->name,
			       (unsigned long long)dev_bytenr,
			       block->mirror_num,
			       (unsigned long long)block->generation,
			       (unsigned long long)
			       le64_to_cpu(block->disk_key.objectid),
			       block->disk_key.type,
			       (unsigned long long)
			       le64_to_cpu(block->disk_key.offset),
			       (unsigned long long)
			       le64_to_cpu(((struct btrfs_header *)