/* * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com) * * * HelenOS: * Copyright (c) 2012 Martin Sucha * Copyright (c) 2012 Frantisek Princ * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright *   notice, this list of conditions and the following disclaimer. * - Redistributions in binary form must reproduce the above copyright *   notice, this list of conditions and the following disclaimer in the *   documentation and/or other materials provided with the distribution. * - The name of the author may not be used to endorse or promote products *   derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /** @addtogroup lwext4 * @{ *//** * @file  ext4_super.h * @brief Superblock operations. */ #include <ext4_config.h>#include <ext4_types.h>#include <ext4_misc.h>#include <ext4_errno.h>#include <ext4_debug.h> #include <ext4_super.h>#include <ext4_crc32.h> uint32_t ext4_block_group_cnt(struct ext4_sblock *s){	uint64_t blocks_count = ext4_sb_get_blocks_cnt(s);	uint32_t blocks_per_group = ext4_get32(s, blocks_per_group); 	uint32_t block_groups_count = (uint32_t)(blocks_count / blocks_per_group); 	if (blocks_count % blocks_per_group)		block_groups_count++; 	return block_groups_count;} uint32_t ext4_blocks_in_group_cnt(struct ext4_sblock *s, uint32_t bgid){	uint32_t block_group_count = ext4_block_group_cnt(s);	uint32_t blocks_per_group = ext4_get32(s, blocks_per_group);	uint64_t total_blocks = ext4_sb_get_blocks_cnt(s); 	if (bgid < block_group_count - 1)		return blocks_per_group; 	return (uint32_t)(total_blocks - ((block_group_count - 1) * blocks_per_group));} uint32_t ext4_inodes_in_group_cnt(struct ext4_sblock *s, uint32_t bgid){	uint32_t block_group_count = ext4_block_group_cnt(s);	uint32_t inodes_per_group = ext4_get32(s, inodes_per_group);	uint32_t total_inodes = ext4_get32(s, inodes_count); 	if (bgid < block_group_count - 1)		return inodes_per_group; 	return (total_inodes - ((block_group_count - 1) * inodes_per_group));} #if CONFIG_META_CSUM_ENABLEstatic uint32_t ext4_sb_csum(struct ext4_sblock *s){ 	return ext4_crc32c(EXT4_CRC32_INIT, s,			offsetof(struct ext4_sblock, checksum));}#else#define ext4_sb_csum(...) 0#endif static bool ext4_sb_verify_csum(struct ext4_sblock *s){	if (!ext4_sb_feature_ro_com(s, EXT4_FRO_COM_METADATA_CSUM))		return true; 	if (s->checksum_type != to_le32(EXT4_CHECKSUM_CRC32C))		return false; 	return s->checksum == to_le32(ext4_sb_csum(s));} void ext4_sb_set_csum(struct ext4_sblock *s){	if (!ext4_sb_feature_ro_com(s, EXT4_FRO_COM_METADATA_CSUM))		return; 	s->checksum = to_le32(ext4_sb_csum(s));} int ext4_sb_write(struct ext4_blockdev *bdev, struct ext4_sblock *s){	ext4_sb_set_csum(s);	return ext4_block_writebytes(bdev, EXT4_SUPERBLOCK_OFFSET, s,				     EXT4_SUPERBLOCK_SIZE);} int ext4_sb_read(struct ext4_blockdev *bdev, struct ext4_sblock *s){	return ext4_block_readbytes(bdev, EXT4_SUPERBLOCK_OFFSET, s,				    EXT4_SUPERBLOCK_SIZE);} bool ext4_sb_check(struct ext4_sblock *s){	if (ext4_get16(s, magic) != EXT4_SUPERBLOCK_MAGIC)		return false; 	if (ext4_get32(s, inodes_count) == 0)		return false; 	if (ext4_sb_get_blocks_cnt(s) == 0)		return false; 	if (ext4_get32(s, blocks_per_group) == 0)		return false; 	if (ext4_get32(s, inodes_per_group) == 0)		return false; 	if (ext4_get16(s, inode_size) < 128)		return false; 	if (ext4_get32(s, first_inode) < 11)		return false; 	if (ext4_sb_get_desc_size(s) < EXT4_MIN_BLOCK_GROUP_DESCRIPTOR_SIZE)		return false; 	if (ext4_sb_get_desc_size(s) > EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)		return false; 	if (!ext4_sb_verify_csum(s))		return false; 	return true;} static inline int is_power_of(uint32_t a, uint32_t b){	while (1) {		if (a < b)			return 0;		if (a == b)			return 1;		if ((a % b) != 0)			return 0;		a = a / b;	}} bool ext4_sb_sparse(uint32_t group){	if (group <= 1)		return 1; 	if (!(group & 1))		return 0; 	return (is_power_of(group, 7) || is_power_of(group, 5) ||		is_power_of(group, 3));} bool ext4_sb_is_super_in_bg(struct ext4_sblock *s, uint32_t group){	if (ext4_sb_feature_ro_com(s, EXT4_FRO_COM_SPARSE_SUPER) &&	    !ext4_sb_sparse(group))		return false;	return true;} static uint32_t ext4_bg_num_gdb_meta(struct ext4_sblock *s, uint32_t group){	uint32_t dsc_per_block =	    ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s); 	uint32_t metagroup = group / dsc_per_block;	uint32_t first = metagroup * dsc_per_block;	uint32_t last = first + dsc_per_block - 1; 	if (group == first || group == first + 1 || group == last)		return 1;	return 0;} static uint32_t ext4_bg_num_gdb_nometa(struct ext4_sblock *s, uint32_t group){	if (!ext4_sb_is_super_in_bg(s, group))		return 0;	uint32_t dsc_per_block =	    ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s); 	uint32_t db_count =	    (ext4_block_group_cnt(s) + dsc_per_block - 1) / dsc_per_block; 	if (ext4_sb_feature_incom(s, EXT4_FINCOM_META_BG))		return ext4_sb_first_meta_bg(s); 	return db_count;} uint32_t ext4_bg_num_gdb(struct ext4_sblock *s, uint32_t group){	uint32_t dsc_per_block =	    ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);	uint32_t first_meta_bg = ext4_sb_first_meta_bg(s);	uint32_t metagroup = group / dsc_per_block; 	if (!ext4_sb_feature_incom(s,EXT4_FINCOM_META_BG) ||	    metagroup < first_meta_bg)		return ext4_bg_num_gdb_nometa(s, group); 	return ext4_bg_num_gdb_meta(s, group);} uint32_t ext4_num_base_meta_clusters(struct ext4_sblock *s,				     uint32_t block_group){	uint32_t num;	uint32_t dsc_per_block =	    ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s); 	num = ext4_sb_is_super_in_bg(s, block_group); 	if (!ext4_sb_feature_incom(s, EXT4_FINCOM_META_BG) ||	    block_group < ext4_sb_first_meta_bg(s) * dsc_per_block) {		if (num) {			num += ext4_bg_num_gdb(s, block_group);			num += ext4_get16(s, s_reserved_gdt_blocks);		}	} else {		num += ext4_bg_num_gdb(s, block_group);	} 	uint32_t clustersize = 1024 << ext4_get32(s, log_cluster_size);	uint32_t cluster_ratio = clustersize / ext4_sb_get_block_size(s);	uint32_t v =	    (num + cluster_ratio - 1) >> ext4_get32(s, log_cluster_size); 	return v;} /** * @} */