ec3/src/image.c

#include "image.h"

#include "bin.h"
#include "pipeline.h"
#include "shadow-image.h"
#include "status.h"

#include <blue/io/directory.h>
#include <blue/io/file.h>
#include <blue/io/path.h>
#include <blue/object/buffer.h>
#include <stdlib.h>
#include <string.h>

B_BTREE_DEFINE_SIMPLE_GET(
	struct ec3_tag_ioctx,
	uint64_t,
	io_node,
	io_tag_info->tag_ident,
	get_opened_tag)
B_BTREE_DEFINE_SIMPLE_INSERT(
	struct ec3_tag_ioctx,
	io_node,
	io_tag_info->tag_ident,
	put_opened_tag)

static enum ec3_status decode_header(
	const struct ec3_header *in,
	struct ec3_image_info *out)
{
	out->img_version = b_i16_btoh(in->h_version);
	out->img_cluster_size
		= ec3_cluster_size_id_to_bytes(b_i16_btoh(in->h_cluster_size));
	out->img_tag_table_offset = b_i64_btoh(in->h_tag_table_offset);
	out->img_extent_table_offset = b_i64_btoh(in->h_extent_table_offset);
	out->img_cluster_table_offset = b_i64_btoh(in->h_cluster_table_offset);
	out->img_cluster_data_offset = sizeof(struct ec3_header);
	out->img_nr_tags = b_i32_btoh(in->h_tag_count);
	out->img_nr_extents = b_i32_btoh(in->h_extent_count);
	out->img_nr_cluster_groups = b_i32_btoh(in->h_cluster_group_count);
	out->img_encryption_function = b_i16_btoh(in->h_encryption);
	out->img_compression_function = b_i16_btoh(in->h_compression);
	out->img_id = b_i64_btoh(in->h_app_magic);

	return EC3_SUCCESS;
}

static void decode_tag(
	const struct ec3_tag_table_entry *in,
	struct ec3_tag_info *out)
{
	out->tag_type = b_i32_btoh(in->tag_type);
	out->tag_flags = b_i32_btoh(in->tag_flags);
	out->tag_checksum = b_i32_btoh(in->tag_checksum);
	out->tag_ident = b_i64_btoh(in->tag_ident);
	out->tag_total_length = b_i64_btoh(in->tag_length);
}

static void decode_extent(
	const struct ec3_extent *in,
	struct ec3_extent_info *out)
{
	out->ex_owner = b_i64_btoh(in->ex_owner);
	out->ex_logical_cluster = b_i32_btoh(in->ex_logical_cluster);
	out->ex_physical_cluster = b_i32_btoh(in->ex_physical_cluster);
	out->ex_count = b_i32_btoh(in->ex_count);
}

static enum ec3_status read_header(
	b_file *image_file,
	struct ec3_image_info *out_info)
{
	struct ec3_header header;
	size_t nr_read;
	enum b_status status
		= b_file_read(image_file, 0, sizeof header, &header, &nr_read);

	if (!B_OK(status)) {
		return ec3_status_from_b_status(status, EC3_ERR_IO_FAILURE);
	}

	return decode_header(&header, out_info);
}

static enum ec3_status read_tag_table(
	b_file *image_file,
	const struct ec3_image_info *image_info,
	b_buffer *out_table)
{
	size_t offset = image_info->img_tag_table_offset;
	b_buffer_resize(out_table, image_info->img_nr_tags);

	struct ec3_tag_table_entry tag;
	size_t nr_read;

	for (size_t i = 0; i < image_info->img_nr_tags; i++) {
		enum b_status status = b_file_read(
			image_file,
			offset,
			sizeof tag,
			&tag,
			&nr_read);

		if (!B_OK(status)) {
			return ec3_status_from_b_status(
				status,
				EC3_ERR_IO_FAILURE);
		}

		if (nr_read != sizeof tag) {
			return EC3_ERR_BAD_FORMAT;
		}

		struct ec3_tag_info *tag_info = b_buffer_get(out_table, i);
		decode_tag(&tag, tag_info);

		offset += sizeof tag;
	}

	return EC3_SUCCESS;
}

static enum ec3_status read_extent_table(
	b_file *image_file,
	const struct ec3_image_info *image_info,
	b_buffer *out_table)
{
	size_t offset = image_info->img_extent_table_offset;
	b_buffer_resize(out_table, image_info->img_nr_extents);

	struct ec3_extent extent;
	size_t nr_read;

	for (size_t i = 0; i < image_info->img_nr_extents; i++) {
		enum b_status status = b_file_read(
			image_file,
			offset,
			sizeof extent,
			&extent,
			&nr_read);

		if (!B_OK(status)) {
			return ec3_status_from_b_status(
				status,
				EC3_ERR_IO_FAILURE);
		}

		if (nr_read != sizeof extent) {
			return EC3_ERR_BAD_FORMAT;
		}

		struct ec3_extent_info *extent_info
			= b_buffer_get(out_table, i);
		decode_extent(&extent, extent_info);

		offset += sizeof extent;
	}

	return EC3_SUCCESS;
}

static enum ec3_status create_ioctx(struct ec3_image_ioctx **out)
{
	struct ec3_image_ioctx *ioctx = malloc(sizeof *ioctx);

	if (!ioctx) {
		return EC3_ERR_NO_MEMORY;
	}

	memset(ioctx, 0x0, sizeof *ioctx);

	ioctx->io_tag_table = b_buffer_create(sizeof(struct ec3_tag_info));
	ioctx->io_extent_table
		= b_buffer_create(sizeof(struct ec3_extent_info));

	*out = ioctx;
	return EC3_SUCCESS;
}

static enum ec3_status open_image_ro(
	b_path *image_path,
	enum ec3_image_ioctx_mode mode,
	struct ec3_image_ioctx **out)
{
	b_file_mode io_mode = B_FILE_READ_ONLY | B_FILE_BINARY;
	b_file *image_file;
	b_status status = b_file_open(
		B_DIRECTORY_ROOT,
		image_path,
		io_mode,
		&image_file);

	if (!B_OK(status)) {
		return EC3_ERR_NO_ENTRY;
	}

	struct ec3_image_ioctx *ioctx;
	enum ec3_status status2 = create_ioctx(&ioctx);
	if (status2 != EC3_SUCCESS) {
		b_file_release(image_file);
		return status2;
	}

	status2 = read_header(image_file, &ioctx->io_header);
	if (status2 != EC3_SUCCESS) {
		b_file_release(image_file);
		return status2;
	}

	status2 = read_tag_table(
		image_file,
		&ioctx->io_header,
		ioctx->io_tag_table);
	if (status2 != EC3_SUCCESS) {
		b_file_release(image_file);
		return status2;
	}

	status2 = read_extent_table(
		image_file,
		&ioctx->io_header,
		ioctx->io_extent_table);
	if (status2 != EC3_SUCCESS) {
		b_file_release(image_file);
		return status2;
	}

	cluster_table_init(
		&ioctx->io_cluster_table,
		image_file,
		ioctx->io_header.img_cluster_table_offset);

	ioctx->io_mode = mode;
	ioctx->io_main = image_file;

	*out = ioctx;
	return EC3_SUCCESS;
}

static enum ec3_status open_image_rw(
	b_path *image_path,
	enum ec3_image_ioctx_mode mode,
	struct ec3_image_ioctx **out)
{
	b_file_mode io_mode = B_FILE_READ_WRITE | B_FILE_BINARY;
	b_file *image_file;
	b_status status = b_file_open(
		B_DIRECTORY_ROOT,
		image_path,
		io_mode,
		&image_file);

	if (!B_OK(status)) {
		return EC3_ERR_NO_ENTRY;
	}

	struct ec3_image_ioctx *ioctx;
	enum ec3_status status2 = create_ioctx(&ioctx);
	if (status2 != EC3_SUCCESS) {
		b_file_release(image_file);
		return status2;
	}

	status2 = read_header(image_file, &ioctx->io_header);
	if (status2 != EC3_SUCCESS) {
		b_file_release(image_file);
		return status2;
	}

	status2 = read_tag_table(
		image_file,
		&ioctx->io_header,
		ioctx->io_tag_table);
	if (status2 != EC3_SUCCESS) {
		b_file_release(image_file);
		return status2;
	}

	status2 = read_extent_table(
		image_file,
		&ioctx->io_header,
		ioctx->io_extent_table);
	if (status2 != EC3_SUCCESS) {
		b_file_release(image_file);
		return status2;
	}

	cluster_table_init(
		&ioctx->io_cluster_table,
		image_file,
		ioctx->io_header.img_cluster_table_offset);

	ioctx->io_mode = mode;
	ioctx->io_main = image_file;

	*out = ioctx;
	return EC3_SUCCESS;
}

static enum ec3_status open_image_create(
	b_path *image_path,
	enum ec3_image_ioctx_mode mode,
	const struct ec3_parameters *param,
	struct ec3_image_ioctx **out)
{
	b_file_mode io_mode = B_FILE_READ_WRITE | B_FILE_CREATE | B_FILE_BINARY;
	b_file *image_file;
	b_status status = b_file_open(
		B_DIRECTORY_ROOT,
		image_path,
		io_mode,
		&image_file);

	if (!B_OK(status)) {
		return EC3_ERR_NO_ENTRY;
	}

	struct ec3_image_ioctx *ioctx;
	enum ec3_status status2 = create_ioctx(&ioctx);
	if (status2 != EC3_SUCCESS) {
		b_file_release(image_file);
		return status2;
	}

	ioctx->io_mode = mode;
	ioctx->io_main = image_file;

	ioctx->io_header.img_id = param->p_ident;
	ioctx->io_header.img_cluster_size
		= ec3_cluster_size_id_to_bytes(param->p_cluster_size);
	ioctx->io_header.img_encryption_function = param->p_encryption_func;
	ioctx->io_header.img_compression_function = param->p_compression_func;
	ioctx->io_header.img_version = EC3_VERSION_1_0;

	*out = ioctx;
	return EC3_SUCCESS;
}

enum ec3_status ec3_image_ioctx_open(
	const char *path,
	const struct ec3_parameters *param,
	enum ec3_image_ioctx_mode mode,
	struct ec3_image_ioctx **out)
{
	if (mode == 0) {
		return EC3_ERR_INVALID_VALUE;
	}

	b_path *image_path = b_path_create_from_cstr(path);
	b_file_info image_info;
	enum b_status status = b_path_stat(image_path, &image_info);

	if ((status == B_ERR_NO_ENTRY) && (mode & EC3_IMAGE_IO_WRITE)) {
		return open_image_create(image_path, mode, param, out);
	}

	if ((status == B_SUCCESS) && (mode & EC3_IMAGE_IO_WRITE)) {
		return open_image_rw(image_path, mode, out);
	}

	if ((status == B_SUCCESS) && (mode & EC3_IMAGE_IO_READ)) {
		return open_image_ro(image_path, mode, out);
	}

	return EC3_ERR_NO_ENTRY;
}

static void destroy_image_ioctx(struct ec3_image_ioctx *image)
{
	if (image->io_main) {
		b_file_release(image->io_main);
	}

	if (image->io_tag_table) {
		b_buffer_release(image->io_tag_table);
	}

	if (image->io_extent_table) {
		b_buffer_release(image->io_extent_table);
	}

	b_btree_iterator it;
	b_btree_iterator_begin(&image->io_opened_tags, &it);
	while (b_btree_iterator_is_valid(&it)) {
		struct ec3_tag_ioctx *tag
			= b_unbox(struct ec3_tag_ioctx, it.node, io_node);
		b_btree_iterator_erase(&it);

		if (tag->io_f_data) {
			b_file_release(tag->io_f_data);
		}

		if (tag->io_f_image) {
			b_file_release(tag->io_f_image);
		}

		if (tag->io_f_cluster_table) {
			b_file_release(tag->io_f_cluster_table);
		}

		free(tag);
	}

	free(image);
}

enum ec3_status ec3_image_ioctx_close(struct ec3_image_ioctx *image)
{
	if (!(image->io_mode & EC3_IMAGE_IO_WRITE)) {
		destroy_image_ioctx(image);
		return EC3_SUCCESS;
	}

	enum ec3_status status = EC3_SUCCESS;
	struct shadow_image shadow;

	status = shadow_image_init(image, &shadow);
	if (status != EC3_SUCCESS) {
		return status;
	}

	const struct ec3_tag_info *tags = ec3_image_ioctx_get_tag_info(image);
	size_t nr_tags = image->io_header.img_nr_tags;

	/* first set of tags to write are those that haven't been opened,
	 * or were opened read-only. we can read clusters directly from
	 * the source image to the dest without re-encoding them */
	for (size_t i = 0; i < nr_tags; i++) {
		const struct ec3_tag_info *tag = &tags[i];

		const struct ec3_tag_ioctx *tag_io = get_opened_tag(
			&image->io_opened_tags,
			tag->tag_ident);
		if (tag_io) {
			/* this tag has been written to. handle it later */
			continue;
		}

		status = shadow_image_write_tag(image, tag, NULL, &shadow);
		if (status != EC3_SUCCESS) {
			shadow_image_cancel(&shadow);
			return status;
		}
	}

	/* next, write the set of tags that have been opened
	 * non-sequential read-write. the modified clusters for these
	 * tags is stored unencoded in an on-disk cache. the unmodified clusters
	 * are read from the original image. each modified cluster needs to be
	 * read into memory, encoded, and written to the dest image
	 */
	for (size_t i = 0; i < nr_tags; i++) {
		const struct ec3_tag_info *tag = &tags[i];

		struct ec3_tag_ioctx *tag_io = get_opened_tag(
			&image->io_opened_tags,
			tag->tag_ident);
		if (!tag_io || !(tag_io->io_mode & EC3_TAG_IO_WRITE)) {
			/* this tag has not been written to, and was handled
			 * earlier */
			continue;
		}

		if (tag_io->io_mode & EC3_TAG_IO_SEQUENTIAL) {
			/* this tag is sequential write-only, and will be
			 * handled later */
			continue;
		}

		status = shadow_image_write_tag(image, tag, tag_io, &shadow);
		if (status != EC3_SUCCESS) {
			shadow_image_cancel(&shadow);
			return status;
		}
	}

	/* finally, write the set of tags that have been opened
	 * sequential write-only. the clusters for these tags
	 * have been written as a single continuous stream of
	 * encoded clusters to a temporary file on-disk, along
	 * with a corresponding cluster table. append the
	 * encoded cluster data directly to the image, and merge
	 * the tag's cluster table with that of the dest image
	 */
	for (size_t i = 0; i < nr_tags; i++) {
		const struct ec3_tag_info *tag = &tags[i];

		struct ec3_tag_ioctx *tag_io = get_opened_tag(
			&image->io_opened_tags,
			tag->tag_ident);
		if (!tag_io || !(tag_io->io_mode & EC3_TAG_IO_WRITE)) {
			/* this tag has not been written to, and was handled
			 * earlier */
			continue;
		}

		if (!(tag_io->io_mode & EC3_TAG_IO_SEQUENTIAL)) {
			/* this tag is not sequential write-only, and was
			 * handled earlier */
			continue;
		}

		status = shadow_image_write_tag(image, tag, tag_io, &shadow);
		if (status != EC3_SUCCESS) {
			shadow_image_cancel(&shadow);
			return status;
		}
	}

	shadow_image_finish(image, &shadow);
	destroy_image_ioctx(image);

	return EC3_SUCCESS;
}

const struct ec3_image_info *ec3_image_ioctx_get_info(
	struct ec3_image_ioctx *image)
{
	return &image->io_header;
}

static const struct ec3_tag_info *get_tag_info_by_type(
	struct ec3_image_ioctx *image,
	uint32_t type,
	unsigned int index)
{
	const struct ec3_tag_info *tags = ec3_image_ioctx_get_tag_info(image);
	size_t nr_tags = image->io_header.img_nr_tags;

	for (size_t i = 0; i < nr_tags; i++) {
		if (tags[i].tag_type != type) {
			continue;
		}

		if (index > 0) {
			index--;
			continue;
		}

		return &tags[i];
	}

	return NULL;
}

static const struct ec3_tag_info *get_tag_info_by_id(
	struct ec3_image_ioctx *image,
	uint64_t id)
{
	const struct ec3_tag_info *tags = ec3_image_ioctx_get_tag_info(image);
	size_t nr_tags = image->io_header.img_nr_tags;

	for (size_t i = 0; i < nr_tags; i++) {
		if (tags[i].tag_ident == id) {
			return &tags[i];
		}
	}

	return NULL;
}

const struct ec3_tag_info *ec3_image_ioctx_get_tag_info(
	struct ec3_image_ioctx *image)
{
	return b_buffer_ptr(image->io_tag_table);
}

const struct ec3_tag_info *ec3_image_ioctx_get_tag_info_by_id(
	struct ec3_image_ioctx *image,
	uint64_t id)
{
	return get_tag_info_by_id(image, id);
}

const struct ec3_extent_info *ec3_image_ioctx_get_extent_info(
	struct ec3_image_ioctx *image)
{
	return b_buffer_ptr(image->io_extent_table);
}

enum ec3_status ec3_image_ioctx_open_string_table(
	struct ec3_image_ioctx *image,
	enum ec3_image_ioctx_mode mode,
	struct string_table **out)
{
	return EC3_ERR_NOT_SUPPORTED;
}

enum ec3_status ec3_image_ioctx_open_chunk_table(
	struct ec3_image_ioctx *image,
	enum ec3_image_ioctx_mode mode,
	struct chunk_table **out)
{
	return EC3_ERR_NOT_SUPPORTED;
}

static uint64_t allocate_tag_id(struct ec3_image_ioctx *image)
{
	uint64_t id = 0;

	const struct ec3_tag_info *tags = ec3_image_ioctx_get_tag_info(image);
	size_t nr_tags = image->io_header.img_nr_tags;

	for (size_t i = 0; i < nr_tags; i++) {
		if (tags[i].tag_ident < 4096 && tags[i].tag_ident > id) {
			id = tags[i].tag_ident + 1;
		}
	}

	return id;
}

static enum ec3_status init_pipeline(
	struct ec3_image_ioctx *image,
	struct ec3_pipeline **pipeline)
{
	struct ec3_pipeline_stage_args stages[2] = {0};

	if (image->io_header.img_compression_function != EC3_COMPRESSION_NONE) {
		stages[0].type = ec3_get_pipeline_stage_for_compression_func(
			image->io_header.img_compression_function);
	}

	if (image->io_header.img_encryption_function != EC3_ENCRYPTION_NONE) {
		stages[1].type = ec3_get_pipeline_stage_for_encryption_func(
			image->io_header.img_encryption_function);
	}

	return ec3_pipeline_create(
		stages,
		sizeof stages / sizeof stages[0],
		image->io_header.img_cluster_size,
		pipeline);
}

static enum ec3_status init_tag_ioctx_ro(
	struct ec3_image_ioctx *image,
	const struct ec3_tag_info *tag_info,
	struct ec3_tag_ioctx *tag)
{
	cluster_table_init(
		&tag->io_cluster_table,
		image->io_main,
		image->io_header.img_cluster_table_offset);

	return EC3_SUCCESS;
}

static enum ec3_status init_tag_ioctx_rw(
	struct ec3_image_ioctx *image,
	const struct ec3_tag_info *tag_info,
	struct ec3_tag_ioctx *tag)
{
	return EC3_SUCCESS;
}

static enum ec3_status init_tag_ioctx_create(
	struct ec3_image_ioctx *image,
	const struct ec3_tag_info *tag_info,
	struct ec3_tag_ioctx *tag)
{
	return EC3_SUCCESS;
}

enum ec3_status ec3_image_ioctx_open_tag_by_type(
	struct ec3_image_ioctx *image,
	uint32_t type,
	unsigned int index,
	enum ec3_tag_ioctx_mode mode,
	struct ec3_tag_ioctx **out)
{
	if ((mode & EC3_TAG_IO_WRITE)
	    && !(image->io_mode & EC3_IMAGE_IO_WRITE)) {
		return EC3_ERR_NOT_SUPPORTED;
	}

	if (!(mode & (EC3_TAG_IO_READ | EC3_TAG_IO_WRITE))) {
		return EC3_ERR_INVALID_VALUE;
	}

	const struct ec3_tag_info *tag_info
		= get_tag_info_by_type(image, type, index);
	if (!tag_info) {
		return EC3_ERR_NO_ENTRY;
	}

	struct ec3_tag_ioctx *tag_ioctx
		= get_opened_tag(&image->io_opened_tags, tag_info->tag_ident);
	if (tag_ioctx) {
		return EC3_ERR_BAD_STATE;
	}

	enum ec3_status status = ec3_tag_ioctx_create(
		&tag_ioctx,
		image->io_header.img_cluster_size,
		mode);

	if (status != EC3_SUCCESS) {
		return status;
	}

	status = init_pipeline(image, &tag_ioctx->io_pipeline);
	if (status != EC3_SUCCESS) {
		ec3_tag_ioctx_close(tag_ioctx);
		return status;
	}

	tag_ioctx->io_mode = mode;
	tag_ioctx->io_parent = image;
	tag_ioctx->io_tag_info = tag_info;
	tag_ioctx->io_f_image = b_file_retain(image->io_main);

	if (mode & EC3_TAG_IO_WRITE) {
		status = init_tag_ioctx_rw(image, tag_info, tag_ioctx);
	} else {
		status = init_tag_ioctx_ro(image, tag_info, tag_ioctx);
	}

	if (status != EC3_SUCCESS) {
		ec3_tag_ioctx_close(tag_ioctx);
		return status;
	}

	*out = tag_ioctx;

	return EC3_SUCCESS;
}

enum ec3_status ec3_image_ioctx_open_tag_by_id(
	struct ec3_image_ioctx *image,
	uint64_t id,
	enum ec3_tag_ioctx_mode mode,
	struct ec3_tag_ioctx **out)
{
	if ((mode & EC3_TAG_IO_WRITE)
	    && !(image->io_mode & EC3_IMAGE_IO_WRITE)) {
		return EC3_ERR_NOT_SUPPORTED;
	}

	if (!(mode & (EC3_TAG_IO_READ | EC3_TAG_IO_WRITE))) {
		return EC3_ERR_INVALID_VALUE;
	}

	const struct ec3_tag_info *tag_info = get_tag_info_by_id(image, id);
	if (!tag_info) {
		return EC3_ERR_NO_ENTRY;
	}

	struct ec3_tag_ioctx *tag_ioctx
		= get_opened_tag(&image->io_opened_tags, tag_info->tag_ident);
	if (tag_ioctx) {
		return EC3_ERR_BAD_STATE;
	}

	enum ec3_status status = ec3_tag_ioctx_create(
		&tag_ioctx,
		image->io_header.img_cluster_size,
		mode);

	if (status != EC3_SUCCESS) {
		return status;
	}

	status = init_pipeline(image, &tag_ioctx->io_pipeline);
	if (status != EC3_SUCCESS) {
		ec3_tag_ioctx_close(tag_ioctx);
		return status;
	}

	tag_ioctx->io_mode = mode;
	tag_ioctx->io_parent = image;
	tag_ioctx->io_tag_info = tag_info;
	tag_ioctx->io_f_image = b_file_retain(image->io_main);

	if (mode & EC3_TAG_IO_WRITE) {
		status = init_tag_ioctx_rw(image, tag_info, tag_ioctx);
	} else {
		status = init_tag_ioctx_ro(image, tag_info, tag_ioctx);
	}

	if (status != EC3_SUCCESS) {
		ec3_tag_ioctx_close(tag_ioctx);
		return status;
	}

	*out = tag_ioctx;

	return EC3_SUCCESS;
}

enum ec3_status ec3_image_ioctx_create_tag(
	struct ec3_image_ioctx *image,
	uint32_t type,
	uint64_t id,
	enum ec3_tag_ioctx_mode mode,
	struct ec3_tag_ioctx **out)
{
	mode |= EC3_TAG_IO_WRITE;

	if (!(image->io_mode & EC3_IMAGE_IO_WRITE)) {
		return EC3_ERR_NOT_SUPPORTED;
	}

	if (id == 0) {
		id = allocate_tag_id(image);
	}

	struct ec3_tag_info *tag_info
		= (struct ec3_tag_info *)get_tag_info_by_id(image, id);

	if (tag_info) {
		return EC3_ERR_NAME_EXISTS;
	}

	struct ec3_tag_ioctx *tag_ioctx
		= get_opened_tag(&image->io_opened_tags, id);
	if (tag_ioctx) {
		return EC3_ERR_BAD_STATE;
	}

	enum ec3_status status = ec3_tag_ioctx_create(
		&tag_ioctx,
		image->io_header.img_cluster_size,
		mode);

	if (status != EC3_SUCCESS) {
		return status;
	}

	status = init_pipeline(image, &tag_ioctx->io_pipeline);
	if (status != EC3_SUCCESS) {
		ec3_tag_ioctx_close(tag_ioctx);
		return status;
	}

	b_buffer_push_back(image->io_tag_table, 1, (void **)&tag_info);

	tag_info->tag_ident = id;
	tag_info->tag_type = type;

	tag_ioctx->io_mode = mode;
	tag_ioctx->io_parent = image;
	tag_ioctx->io_tag_info = tag_info;
	tag_ioctx->io_f_image = b_file_retain(image->io_main);

	status = init_tag_ioctx_create(image, tag_info, tag_ioctx);

	if (status != EC3_SUCCESS) {
		b_buffer_pop_back(image->io_tag_table, 1);
		ec3_tag_ioctx_close(tag_ioctx);
		return status;
	}

	image->io_header.img_nr_tags++;
	put_opened_tag(&image->io_opened_tags, tag_ioctx);

	*out = tag_ioctx;

	return EC3_SUCCESS;
}

enum ec3_status ec3_image_ioctx_cluster_logical_to_physical(
	struct ec3_image_ioctx *image,
	const struct ec3_tag_info *tag,
	size_t logical_cluster,
	size_t *out_physical_cluster)
{
	const struct ec3_extent_info *extents
		= b_buffer_ptr(image->io_extent_table);
	size_t nr_extents = image->io_header.img_nr_extents;

	for (size_t i = 0; i < nr_extents; i++) {
		const struct ec3_extent_info *x = &extents[i];

		if (x->ex_owner != tag->tag_ident) {
			continue;
		}

		if (logical_cluster < x->ex_logical_cluster
		    || logical_cluster >= x->ex_logical_cluster + x->ex_count) {
			continue;
		}

		*out_physical_cluster
			= x->ex_physical_cluster
		        + (logical_cluster - x->ex_logical_cluster);
		return EC3_SUCCESS;
	}

	return EC3_ERR_OUT_OF_BOUNDS;
}

enum ec3_status ec3_image_ioctx_get_tag_nr_clusters(
	struct ec3_image_ioctx *image,
	const struct ec3_tag_info *tag,
	size_t *out_nr_clusters)
{
	size_t nr_clusters = 0;

	const struct ec3_extent_info *extents
		= ec3_image_ioctx_get_extent_info(image);
	size_t nr_extents = image->io_header.img_nr_extents;

	for (size_t i = 0; i < nr_extents; i++) {
		const struct ec3_extent_info *x = &extents[i];
		if (x->ex_owner != tag->tag_ident) {
			continue;
		}

		if (x->ex_logical_cluster + x->ex_count > nr_clusters) {
			nr_clusters = x->ex_logical_cluster + x->ex_count;
		}
	}

	struct ec3_tag_ioctx *tag_ioctx
		= get_opened_tag(&image->io_opened_tags, tag->tag_ident);

	if (!tag_ioctx) {
		*out_nr_clusters = nr_clusters;
		return EC3_SUCCESS;
	}

	size_t highest_cached_cluster;

	enum ec3_status status = cluster_cache_get_highest_cluster_id(
		&tag_ioctx->io_cache,
		&highest_cached_cluster);

	if (status == EC3_SUCCESS && highest_cached_cluster >= nr_clusters) {
		nr_clusters = highest_cached_cluster + 1;
	}

	*out_nr_clusters = nr_clusters;
	return EC3_SUCCESS;
}