ref: ab4ac2567203f642959e0ff8a88425254d121a52
dir: /src/ext4_super.c/
/* * Copyright (c) 2013 Grzegorz Kostka ([email protected]) * * * 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_ENABLE static 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)); } static 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; } /** * @} */