fs/minix/itree_v2.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/buffer_head.h>
   3 #include "minix.h"
   4
   5 enum {DIRECT = 7, DEPTH = 4};   /* Have triple indirect */
   6
   7 typedef u32 block_t;    /* 32 bit, host order */
   8
   9 static inline unsigned long block_to_cpu(block_t n)
  10 {
  11         return n;
  12 }
  13
  14 static inline block_t cpu_to_block(unsigned long n)
  15 {
  16         return n;
  17 }
  18
  19 static inline block_t *i_data(struct inode *inode)
  20 {
  21         return (block_t *)minix_i(inode)->u.i2_data;
  22 }
  23
  24 #define DIRCOUNT 7
  25 #define INDIRCOUNT(sb) (1 << ((sb)->s_blocksize_bits - 2))
  26
  27 static int block_to_path(struct inode * inode, long block, int offsets[DEPTH])
  28 {
  29         int n = 0;
  30         struct super_block *sb = inode->i_sb;
  31
  32         if (block < 0) {
  33                 printk("MINIX-fs: block_to_path: block %ld < 0 on dev %pg\n",
  34                         block, sb->s_bdev);
  35                 return 0;
  36         }
  37         if ((u64)block * (u64)sb->s_blocksize >= sb->s_maxbytes)
  38                 return 0;
  39
  40         if (block < DIRCOUNT) {
  41                 offsets[n++] = block;
  42         } else if ((block -= DIRCOUNT) < INDIRCOUNT(sb)) {
  43                 offsets[n++] = DIRCOUNT;
  44                 offsets[n++] = block;
  45         } else if ((block -= INDIRCOUNT(sb)) < INDIRCOUNT(sb) * INDIRCOUNT(sb)) {
  46                 offsets[n++] = DIRCOUNT + 1;
  47                 offsets[n++] = block / INDIRCOUNT(sb);
  48                 offsets[n++] = block % INDIRCOUNT(sb);
  49         } else {
  50                 block -= INDIRCOUNT(sb) * INDIRCOUNT(sb);
  51                 offsets[n++] = DIRCOUNT + 2;
  52                 offsets[n++] = (block / INDIRCOUNT(sb)) / INDIRCOUNT(sb);
  53                 offsets[n++] = (block / INDIRCOUNT(sb)) % INDIRCOUNT(sb);
  54                 offsets[n++] = block % INDIRCOUNT(sb);
  55         }
  56         return n;
  57 }
  58
  59 #include "itree_common.c"
  60
  61 int V2_minix_get_block(struct inode * inode, long block,
  62                         struct buffer_head *bh_result, int create)
  63 {
  64         return get_block(inode, block, bh_result, create);
  65 }
  66
  67 void V2_minix_truncate(struct inode * inode)
  68 {
  69         truncate(inode);
  70 }
  71
  72 unsigned V2_minix_blocks(loff_t size, struct super_block *sb)
  73 {
  74         return nblocks(size, sb);
  75 }