linux/fs/ufs/cylinder.c
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   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 */
  29static 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        
  72failed:
  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 */
  83void 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 */
 127struct 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}
 203