1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/ext4/bitmap.c 4 * 5 * Copyright (C) 1992, 1993, 1994, 1995 6 * Remy Card (card@masi.ibp.fr) 7 * Laboratoire MASI - Institut Blaise Pascal 8 * Universite Pierre et Marie Curie (Paris VI) 9 */ 10 11 #include <linux/buffer_head.h> 12 #include "ext4.h" 13 14 unsigned int ext4_count_free(char *bitmap, unsigned int numchars) 15 { 16 return numchars * BITS_PER_BYTE - memweight(bitmap, numchars); 17 } 18 19 int ext4_inode_bitmap_csum_verify(struct super_block *sb, 20 struct ext4_group_desc *gdp, 21 struct buffer_head *bh) 22 { 23 __u32 hi; 24 __u32 provided, calculated; 25 struct ext4_sb_info *sbi = EXT4_SB(sb); 26 int sz; 27 28 if (!ext4_has_metadata_csum(sb)) 29 return 1; 30 31 sz = EXT4_INODES_PER_GROUP(sb) >> 3; 32 provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo); 33 calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); 34 if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) { 35 hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi); 36 provided |= (hi << 16); 37 } else 38 calculated &= 0xFFFF; 39 40 return provided == calculated; 41 } 42 43 void ext4_inode_bitmap_csum_set(struct super_block *sb, 44 struct ext4_group_desc *gdp, 45 struct buffer_head *bh) 46 { 47 __u32 csum; 48 struct ext4_sb_info *sbi = EXT4_SB(sb); 49 int sz; 50 51 if (!ext4_has_metadata_csum(sb)) 52 return; 53 54 sz = EXT4_INODES_PER_GROUP(sb) >> 3; 55 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); 56 gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF); 57 if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) 58 gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16); 59 } 60 61 int ext4_block_bitmap_csum_verify(struct super_block *sb, 62 struct ext4_group_desc *gdp, 63 struct buffer_head *bh) 64 { 65 __u32 hi; 66 __u32 provided, calculated; 67 struct ext4_sb_info *sbi = EXT4_SB(sb); 68 int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8; 69 70 if (!ext4_has_metadata_csum(sb)) 71 return 1; 72 73 provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo); 74 calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); 75 if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) { 76 hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi); 77 provided |= (hi << 16); 78 } else 79 calculated &= 0xFFFF; 80 81 return provided == calculated; 82 } 83 84 void ext4_block_bitmap_csum_set(struct super_block *sb, 85 struct ext4_group_desc *gdp, 86 struct buffer_head *bh) 87 { 88 int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8; 89 __u32 csum; 90 struct ext4_sb_info *sbi = EXT4_SB(sb); 91 92 if (!ext4_has_metadata_csum(sb)) 93 return; 94 95 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); 96 gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF); 97 if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) 98 gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16); 99 } 100