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, ext4_group_t group, 20 struct ext4_group_desc *gdp, 21 struct buffer_head *bh, int sz) 22 { 23 __u32 hi; 24 __u32 provided, calculated; 25 struct ext4_sb_info *sbi = EXT4_SB(sb); 26 27 if (!ext4_has_metadata_csum(sb)) 28 return 1; 29 30 provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo); 31 calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); 32 if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) { 33 hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi); 34 provided |= (hi << 16); 35 } else 36 calculated &= 0xFFFF; 37 38 return provided == calculated; 39 } 40 41 void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group, 42 struct ext4_group_desc *gdp, 43 struct buffer_head *bh, int sz) 44 { 45 __u32 csum; 46 struct ext4_sb_info *sbi = EXT4_SB(sb); 47 48 if (!ext4_has_metadata_csum(sb)) 49 return; 50 51 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); 52 gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF); 53 if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) 54 gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16); 55 } 56 57 int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group, 58 struct ext4_group_desc *gdp, 59 struct buffer_head *bh) 60 { 61 __u32 hi; 62 __u32 provided, calculated; 63 struct ext4_sb_info *sbi = EXT4_SB(sb); 64 int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8; 65 66 if (!ext4_has_metadata_csum(sb)) 67 return 1; 68 69 provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo); 70 calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); 71 if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) { 72 hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi); 73 provided |= (hi << 16); 74 } else 75 calculated &= 0xFFFF; 76 77 if (provided == calculated) 78 return 1; 79 80 return 0; 81 } 82 83 void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group, 84 struct ext4_group_desc *gdp, 85 struct buffer_head *bh) 86 { 87 int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8; 88 __u32 csum; 89 struct ext4_sb_info *sbi = EXT4_SB(sb); 90 91 if (!ext4_has_metadata_csum(sb)) 92 return; 93 94 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); 95 gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF); 96 if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) 97 gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16); 98 } 99