Line data    Source code

       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           0 : unsigned int ext4_count_free(char *bitmap, unsigned int numchars)
      15             : {
      16           0 :         return numchars * BITS_PER_BYTE - memweight(bitmap, numchars);
      17             : }
      18             : 
      19           6 : 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           6 :         __u32 hi;
      24           6 :         __u32 provided, calculated;
      25           6 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
      26             : 
      27           6 :         if (!ext4_has_metadata_csum(sb))
      28             :                 return 1;
      29             : 
      30           0 :         provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo);
      31           0 :         calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
      32           0 :         if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) {
      33           0 :                 hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi);
      34           0 :                 provided |= (hi << 16);
      35             :         } else
      36           0 :                 calculated &= 0xFFFF;
      37             : 
      38           0 :         return provided == calculated;
      39             : }
      40             : 
      41         811 : 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         811 :         __u32 csum;
      46         811 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
      47             : 
      48         811 :         if (!ext4_has_metadata_csum(sb))
      49             :                 return;
      50             : 
      51           0 :         csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
      52           0 :         gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
      53           0 :         if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
      54           0 :                 gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16);
      55             : }
      56             : 
      57          16 : 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          16 :         __u32 hi;
      62          16 :         __u32 provided, calculated;
      63          16 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
      64          16 :         int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
      65             : 
      66          16 :         if (!ext4_has_metadata_csum(sb))
      67             :                 return 1;
      68             : 
      69           0 :         provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo);
      70           0 :         calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
      71           0 :         if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) {
      72           0 :                 hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi);
      73           0 :                 provided |= (hi << 16);
      74             :         } else
      75           0 :                 calculated &= 0xFFFF;
      76             : 
      77           0 :         if (provided == calculated)
      78           0 :                 return 1;
      79             : 
      80             :         return 0;
      81             : }
      82             : 
      83         451 : 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         451 :         int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
      88         451 :         __u32 csum;
      89         451 :         struct ext4_sb_info *sbi = EXT4_SB(sb);
      90             : 
      91         451 :         if (!ext4_has_metadata_csum(sb))
      92             :                 return;
      93             : 
      94           0 :         csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
      95           0 :         gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
      96           0 :         if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END)
      97           0 :                 gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16);
      98             : }