root/fs/ufs/cylinder.c

DEFINITIONS

1. ufs_read_cylinder
2. ufs_put_cylinder
3. ufs_load_cylinder

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/ufs/cylinder.c
   4  *
   5  * Copyright (C) 1998
   6  * Daniel Pirkl <daniel.pirkl@email.cz>
   7  * Charles University, Faculty of Mathematics and Physics
   8  *
   9  *  ext2 - inode (block) bitmap caching inspired
  10  */
  11 
  12 #include <linux/fs.h>
  13 #include <linux/time.h>
  14 #include <linux/stat.h>
  15 #include <linux/string.h>
  16 #include <linux/bitops.h>
  17 
  18 #include <asm/byteorder.h>
  19 
  20 #include "ufs_fs.h"
  21 #include "ufs.h"
  22 #include "swab.h"
  23 #include "util.h"
  24 
  25 /*
  26  * Read cylinder group into cache. The memory space for ufs_cg_private_info
  27  * structure is already allocated during ufs_read_super.
  28  */
  29 static void ufs_read_cylinder (struct super_block * sb,
  30         unsigned cgno, unsigned bitmap_nr)
  31 {
  32         struct ufs_sb_info * sbi = UFS_SB(sb);
  33         struct ufs_sb_private_info * uspi;
  34         struct ufs_cg_private_info * ucpi;
  35         struct ufs_cylinder_group * ucg;
  36         unsigned i, j;
  37 
  38         UFSD("ENTER, cgno %u, bitmap_nr %u\n", cgno, bitmap_nr);
  39         uspi = sbi->s_uspi;
  40         ucpi = sbi->s_ucpi[bitmap_nr];
  41         ucg = (struct ufs_cylinder_group *)sbi->s_ucg[cgno]->b_data;
  42 
  43         UCPI_UBH(ucpi)->fragment = ufs_cgcmin(cgno);
  44         UCPI_UBH(ucpi)->count = uspi->s_cgsize >> sb->s_blocksize_bits;
  45         /*
  46          * We have already the first fragment of cylinder group block in buffer
  47          */
  48         UCPI_UBH(ucpi)->bh[0] = sbi->s_ucg[cgno];
  49         for (i = 1; i < UCPI_UBH(ucpi)->count; i++)
  50                 if (!(UCPI_UBH(ucpi)->bh[i] = sb_bread(sb, UCPI_UBH(ucpi)->fragment + i)))
  51                         goto failed;
  52         sbi->s_cgno[bitmap_nr] = cgno;
  53                         
  54         ucpi->c_cgx     = fs32_to_cpu(sb, ucg->cg_cgx);
  55         ucpi->c_ncyl    = fs16_to_cpu(sb, ucg->cg_ncyl);
  56         ucpi->c_niblk   = fs16_to_cpu(sb, ucg->cg_niblk);
  57         ucpi->c_ndblk   = fs32_to_cpu(sb, ucg->cg_ndblk);
  58         ucpi->c_rotor   = fs32_to_cpu(sb, ucg->cg_rotor);
  59         ucpi->c_frotor  = fs32_to_cpu(sb, ucg->cg_frotor);
  60         ucpi->c_irotor  = fs32_to_cpu(sb, ucg->cg_irotor);
  61         ucpi->c_btotoff = fs32_to_cpu(sb, ucg->cg_btotoff);
  62         ucpi->c_boff    = fs32_to_cpu(sb, ucg->cg_boff);
  63         ucpi->c_iusedoff = fs32_to_cpu(sb, ucg->cg_iusedoff);
  64         ucpi->c_freeoff = fs32_to_cpu(sb, ucg->cg_freeoff);
  65         ucpi->c_nextfreeoff = fs32_to_cpu(sb, ucg->cg_nextfreeoff);
  66         ucpi->c_clustersumoff = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_clustersumoff);
  67         ucpi->c_clusteroff = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_clusteroff);
  68         ucpi->c_nclusterblks = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_nclusterblks);
  69         UFSD("EXIT\n");
  70         return; 
  71         
  72 failed:
  73         for (j = 1; j < i; j++)
  74                 brelse (sbi->s_ucg[j]);
  75         sbi->s_cgno[bitmap_nr] = UFS_CGNO_EMPTY;
  76         ufs_error (sb, "ufs_read_cylinder", "can't read cylinder group block %u", cgno);
  77 }
  78 
  79 /*
  80  * Remove cylinder group from cache, doesn't release memory
  81  * allocated for cylinder group (this is done at ufs_put_super only).
  82  */
  83 void ufs_put_cylinder (struct super_block * sb, unsigned bitmap_nr)
  84 {
  85         struct ufs_sb_info * sbi = UFS_SB(sb);
  86         struct ufs_sb_private_info * uspi; 
  87         struct ufs_cg_private_info * ucpi;
  88         struct ufs_cylinder_group * ucg;
  89         unsigned i;
  90 
  91         UFSD("ENTER, bitmap_nr %u\n", bitmap_nr);
  92 
  93         uspi = sbi->s_uspi;
  94         if (sbi->s_cgno[bitmap_nr] == UFS_CGNO_EMPTY) {
  95                 UFSD("EXIT\n");
  96                 return;
  97         }
  98         ucpi = sbi->s_ucpi[bitmap_nr];
  99         ucg = ubh_get_ucg(UCPI_UBH(ucpi));
 100 
 101         if (uspi->s_ncg > UFS_MAX_GROUP_LOADED && bitmap_nr >= sbi->s_cg_loaded) {
 102                 ufs_panic (sb, "ufs_put_cylinder", "internal error");
 103                 return;
 104         }
 105         /*
 106          * rotor is not so important data, so we put it to disk 
 107          * at the end of working with cylinder
 108          */
 109         ucg->cg_rotor = cpu_to_fs32(sb, ucpi->c_rotor);
 110         ucg->cg_frotor = cpu_to_fs32(sb, ucpi->c_frotor);
 111         ucg->cg_irotor = cpu_to_fs32(sb, ucpi->c_irotor);
 112         ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
 113         for (i = 1; i < UCPI_UBH(ucpi)->count; i++) {
 114                 brelse (UCPI_UBH(ucpi)->bh[i]);
 115         }
 116 
 117         sbi->s_cgno[bitmap_nr] = UFS_CGNO_EMPTY;
 118         UFSD("EXIT\n");
 119 }
 120 
 121 /*
 122  * Find cylinder group in cache and return it as pointer.
 123  * If cylinder group is not in cache, we will load it from disk.
 124  *
 125  * The cache is managed by LRU algorithm. 
 126  */
 127 struct ufs_cg_private_info * ufs_load_cylinder (
 128         struct super_block * sb, unsigned cgno)
 129 {
 130         struct ufs_sb_info * sbi = UFS_SB(sb);
 131         struct ufs_sb_private_info * uspi;
 132         struct ufs_cg_private_info * ucpi;
 133         unsigned cg, i, j;
 134 
 135         UFSD("ENTER, cgno %u\n", cgno);
 136 
 137         uspi = sbi->s_uspi;
 138         if (cgno >= uspi->s_ncg) {
 139                 ufs_panic (sb, "ufs_load_cylinder", "internal error, high number of cg");
 140                 return NULL;
 141         }
 142         /*
 143          * Cylinder group number cg it in cache and it was last used
 144          */
 145         if (sbi->s_cgno[0] == cgno) {
 146                 UFSD("EXIT\n");
 147                 return sbi->s_ucpi[0];
 148         }
 149         /*
 150          * Number of cylinder groups is not higher than UFS_MAX_GROUP_LOADED
 151          */
 152         if (uspi->s_ncg <= UFS_MAX_GROUP_LOADED) {
 153                 if (sbi->s_cgno[cgno] != UFS_CGNO_EMPTY) {
 154                         if (sbi->s_cgno[cgno] != cgno) {
 155                                 ufs_panic (sb, "ufs_load_cylinder", "internal error, wrong number of cg in cache");
 156                                 UFSD("EXIT (FAILED)\n");
 157                                 return NULL;
 158                         }
 159                         else {
 160                                 UFSD("EXIT\n");
 161                                 return sbi->s_ucpi[cgno];
 162                         }
 163                 } else {
 164                         ufs_read_cylinder (sb, cgno, cgno);
 165                         UFSD("EXIT\n");
 166                         return sbi->s_ucpi[cgno];
 167                 }
 168         }
 169         /*
 170          * Cylinder group number cg is in cache but it was not last used, 
 171          * we will move to the first position
 172          */
 173         for (i = 0; i < sbi->s_cg_loaded && sbi->s_cgno[i] != cgno; i++);
 174         if (i < sbi->s_cg_loaded && sbi->s_cgno[i] == cgno) {
 175                 cg = sbi->s_cgno[i];
 176                 ucpi = sbi->s_ucpi[i];
 177                 for (j = i; j > 0; j--) {
 178                         sbi->s_cgno[j] = sbi->s_cgno[j-1];
 179                         sbi->s_ucpi[j] = sbi->s_ucpi[j-1];
 180                 }
 181                 sbi->s_cgno[0] = cg;
 182                 sbi->s_ucpi[0] = ucpi;
 183         /*
 184          * Cylinder group number cg is not in cache, we will read it from disk
 185          * and put it to the first position
 186          */
 187         } else {
 188                 if (sbi->s_cg_loaded < UFS_MAX_GROUP_LOADED)
 189                         sbi->s_cg_loaded++;
 190                 else
 191                         ufs_put_cylinder (sb, UFS_MAX_GROUP_LOADED-1);
 192                 ucpi = sbi->s_ucpi[sbi->s_cg_loaded - 1];
 193                 for (j = sbi->s_cg_loaded - 1; j > 0; j--) {
 194                         sbi->s_cgno[j] = sbi->s_cgno[j-1];
 195                         sbi->s_ucpi[j] = sbi->s_ucpi[j-1];
 196                 }
 197                 sbi->s_ucpi[0] = ucpi;
 198                 ufs_read_cylinder (sb, cgno, 0);
 199         }
 200         UFSD("EXIT\n");
 201         return sbi->s_ucpi[0];
 202 }