Commit 427bf2c1 authored by Bruce Johnston's avatar Bruce Johnston Committed by Mikulas Patocka
Browse files

dm vdo: add geometry block encoding 



Add vdo_encode_volume_geometry() to write the geometry block into a
buffer so that it can be written to disk. The corresponding decode
path already exists.

Signed-off-by: default avatarBruce Johnston <bjohnsto@redhat.com>
Reviewed-by: default avatarMatthew Sakai <msakai@redhat.com>
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
parent beced130

drivers/md/dm-vdo/encodings.c

+56 −0
Original line number Diff line number Diff line
@@ -287,6 +287,62 @@ static void decode_volume_geometry(u8 *buffer, size_t *offset, 
	};

}



/**

 * vdo_encode_volume_geometry() - Encode the on-disk representation of a volume geometry into a buffer.

 * @buffer: A buffer to store the encoding.

 * @geometry: The geometry to encode.

 * @version: The geometry block version to encode.

 *

 * Return: VDO_SUCCESS or an error.

 */

int vdo_encode_volume_geometry(u8 *buffer, const struct volume_geometry *geometry,

			       u32 version)

{

	int result;

	enum volume_region_id id;

	u32 checksum;

	size_t offset = 0;

	const struct header *header;



	memcpy(buffer, VDO_GEOMETRY_MAGIC_NUMBER, VDO_GEOMETRY_MAGIC_NUMBER_SIZE);

	offset += VDO_GEOMETRY_MAGIC_NUMBER_SIZE;



	header = (version > 4) ? &GEOMETRY_BLOCK_HEADER_5_0 : &GEOMETRY_BLOCK_HEADER_4_0;

	vdo_encode_header(buffer, &offset, header);



	/* This is for backwards compatibility */

	encode_u32_le(buffer, &offset, geometry->unused);

	encode_u64_le(buffer, &offset, geometry->nonce);

	memcpy(buffer + offset, (unsigned char *) &geometry->uuid, sizeof(uuid_t));

	offset += sizeof(uuid_t);



	if (version > 4)

		encode_u64_le(buffer, &offset, geometry->bio_offset);



	for (id = 0; id < VDO_VOLUME_REGION_COUNT; id++) {

		encode_u32_le(buffer, &offset, geometry->regions[id].id);

		encode_u64_le(buffer, &offset, geometry->regions[id].start_block);

	}



	encode_u32_le(buffer, &offset, geometry->index_config.mem);

	encode_u32_le(buffer, &offset, 0);



	if (geometry->index_config.sparse)

		buffer[offset++] = 1;

	else

		buffer[offset++] = 0;



	result = VDO_ASSERT(header->size == offset + sizeof(u32),

			    "should have encoded up to the geometry checksum");

	if (result != VDO_SUCCESS)

		return result;



	checksum = vdo_crc32(buffer, offset);

	encode_u32_le(buffer, &offset, checksum);



	return VDO_SUCCESS;

}



/**

 * vdo_parse_geometry_block() - Decode and validate an encoded geometry block.

 * @block: The encoded geometry block.

drivers/md/dm-vdo/encodings.h

+2 −0
Original line number Diff line number Diff line
@@ -813,6 +813,8 @@ int vdo_initialize_volume_geometry(nonce_t nonce, uuid_t *uuid, 
				   const struct index_config *index_config,

				   struct volume_geometry *geometry);



int vdo_encode_volume_geometry(u8 *buffer, const struct volume_geometry *geometry,

			       u32 version);

int __must_check vdo_parse_geometry_block(unsigned char *block,

					  struct volume_geometry *geometry);