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