fs/ufs/cylinder.c

   1 /*
   2  *  linux/fs/ufs/cylinder.c
   3  *
   4  * Copyright (C) 1998
   5  * Daniel Pirkl <daniel.pirkl@email.cz>
   6  * Charles University, Faculty of Mathematics and Physics
   7  *
   8  *  ext2 - inode (block) bitmap caching inspired
   9  */
  10
  11 #include <linux/fs.h>
  12 #include <linux/ufs_fs.h>
  13 #include <linux/sched.h>
  14 #include <linux/stat.h>
  15 #include <linux/string.h>
  16 #include <linux/locks.h>
  17
  18 #include <asm/bitops.h>
  19 #include <asm/byteorder.h>
  20
  21 #include "swab.h"
  22 #include "util.h"
  23
  24 #undef UFS_CYLINDER_DEBUG
  25
  26 #ifdef UFS_CYLINDER_DEBUG
  27 #define UFSD(x) printk("(%s, %d), %s:", __FILE__, __LINE__, __FUNCTION__); printk x;
  28 #else
  29 #define UFSD(x)
  30 #endif
  31
  32
  33 /*
  34  * Read cylinder group into cache. The memory space for ufs_cg_private_info
  35  * structure is already allocated during ufs_read_super.
  36  */
  37 static void ufs_read_cylinder (struct super_block * sb,
  38         unsigned cgno, unsigned bitmap_nr)
  39 {
  40         struct ufs_sb_private_info * uspi;
  41         struct ufs_cg_private_info * ucpi;
  42         struct ufs_cylinder_group * ucg;
  43         unsigned i, j;
  44
  45         UFSD(("ENTER, cgno %u, bitmap_nr %u\n", cgno, bitmap_nr))
  46         uspi = sb->u.ufs_sb.s_uspi;
  47         ucpi = sb->u.ufs_sb.s_ucpi[bitmap_nr];
  48         ucg = (struct ufs_cylinder_group *)sb->u.ufs_sb.s_ucg[cgno]->b_data;
  49
  50         UCPI_UBH->fragment = ufs_cgcmin(cgno);
  51         UCPI_UBH->count = uspi->s_cgsize >> sb->s_blocksize_bits;
  52         /*
  53          * We have already the first fragment of cylinder group block in buffer
  54          */
  55         UCPI_UBH->bh[0] = sb->u.ufs_sb.s_ucg[cgno];
  56         for (i = 1; i < UCPI_UBH->count; i++)
  57                 if (!(UCPI_UBH->bh[i] = sb_bread(sb, UCPI_UBH->fragment + i)))
  58                         goto failed;
  59         sb->u.ufs_sb.s_cgno[bitmap_nr] = cgno;
  60
  61         ucpi->c_cgx     = fs32_to_cpu(sb, ucg->cg_cgx);
  62         ucpi->c_ncyl    = fs16_to_cpu(sb, ucg->cg_ncyl);
  63         ucpi->c_niblk   = fs16_to_cpu(sb, ucg->cg_niblk);
  64         ucpi->c_ndblk   = fs32_to_cpu(sb, ucg->cg_ndblk);
  65         ucpi->c_rotor   = fs32_to_cpu(sb, ucg->cg_rotor);
  66         ucpi->c_frotor  = fs32_to_cpu(sb, ucg->cg_frotor);
  67         ucpi->c_irotor  = fs32_to_cpu(sb, ucg->cg_irotor);
  68         ucpi->c_btotoff = fs32_to_cpu(sb, ucg->cg_btotoff);
  69         ucpi->c_boff    = fs32_to_cpu(sb, ucg->cg_boff);
  70         ucpi->c_iusedoff = fs32_to_cpu(sb, ucg->cg_iusedoff);
  71         ucpi->c_freeoff = fs32_to_cpu(sb, ucg->cg_freeoff);
  72         ucpi->c_nextfreeoff = fs32_to_cpu(sb, ucg->cg_nextfreeoff);
  73         ucpi->c_clustersumoff = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_clustersumoff);
  74         ucpi->c_clusteroff = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_clusteroff);
  75         ucpi->c_nclusterblks = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_nclusterblks);
  76         UFSD(("EXIT\n"))
  77         return;
  78
  79 failed:
  80         for (j = 1; j < i; j++)
  81                 brelse (sb->u.ufs_sb.s_ucg[j]);
  82         sb->u.ufs_sb.s_cgno[bitmap_nr] = UFS_CGNO_EMPTY;
  83         ufs_error (sb, "ufs_read_cylinder", "can't read cylinder group block %u", cgno);
  84 }
  85
  86 /*
  87  * Remove cylinder group from cache, doesn't release memory
  88  * allocated for cylinder group (this is done at ufs_put_super only).
  89  */
  90 void ufs_put_cylinder (struct super_block * sb, unsigned bitmap_nr)
  91 {
  92         struct ufs_sb_private_info * uspi;
  93         struct ufs_cg_private_info * ucpi;
  94         struct ufs_cylinder_group * ucg;
  95         unsigned i;
  96
  97         UFSD(("ENTER, bitmap_nr %u\n", bitmap_nr))
  98
  99         uspi = sb->u.ufs_sb.s_uspi;
 100         if (sb->u.ufs_sb.s_cgno[bitmap_nr] == UFS_CGNO_EMPTY) {
 101                 UFSD(("EXIT\n"))
 102                 return;
 103         }
 104         ucpi = sb->u.ufs_sb.s_ucpi[bitmap_nr];
 105         ucg = ubh_get_ucg(UCPI_UBH);
 106
 107         if (uspi->s_ncg > UFS_MAX_GROUP_LOADED && bitmap_nr >= sb->u.ufs_sb.s_cg_loaded) {
 108                 ufs_panic (sb, "ufs_put_cylinder", "internal error");
 109                 return;
 110         }
 111         /*
 112          * rotor is not so important data, so we put it to disk
 113          * at the end of working with cylinder
 114          */
 115         ucg->cg_rotor = cpu_to_fs32(sb, ucpi->c_rotor);
 116         ucg->cg_frotor = cpu_to_fs32(sb, ucpi->c_frotor);
 117         ucg->cg_irotor = cpu_to_fs32(sb, ucpi->c_irotor);
 118         ubh_mark_buffer_dirty (UCPI_UBH);
 119         for (i = 1; i < UCPI_UBH->count; i++) {
 120                 brelse (UCPI_UBH->bh[i]);
 121         }
 122
 123         sb->u.ufs_sb.s_cgno[bitmap_nr] = UFS_CGNO_EMPTY;
 124         UFSD(("EXIT\n"))
 125 }
 126
 127 /*
 128  * Find cylinder group in cache and return it as pointer.
 129  * If cylinder group is not in cache, we will load it from disk.
 130  *
 131  * The cache is managed by LRU algorithm.
 132  */
 133 struct ufs_cg_private_info * ufs_load_cylinder (
 134         struct super_block * sb, unsigned cgno)
 135 {
 136         struct ufs_sb_private_info * uspi;
 137         struct ufs_cg_private_info * ucpi;
 138         unsigned cg, i, j;
 139
 140         UFSD(("ENTER, cgno %u\n", cgno))
 141
 142         uspi = sb->u.ufs_sb.s_uspi;
 143         if (cgno >= uspi->s_ncg) {
 144                 ufs_panic (sb, "ufs_load_cylinder", "internal error, high number of cg");
 145                 return NULL;
 146         }
 147         /*
 148          * Cylinder group number cg it in cache and it was last used
 149          */
 150         if (sb->u.ufs_sb.s_cgno[0] == cgno) {
 151                 UFSD(("EXIT\n"))
 152                 return sb->u.ufs_sb.s_ucpi[0];
 153         }
 154         /*
 155          * Number of cylinder groups is not higher than UFS_MAX_GROUP_LOADED
 156          */
 157         if (uspi->s_ncg <= UFS_MAX_GROUP_LOADED) {
 158                 if (sb->u.ufs_sb.s_cgno[cgno] != UFS_CGNO_EMPTY) {
 159                         if (sb->u.ufs_sb.s_cgno[cgno] != cgno) {
 160                                 ufs_panic (sb, "ufs_load_cylinder", "internal error, wrong number of cg in cache");
 161                                 UFSD(("EXIT (FAILED)\n"))
 162                                 return NULL;
 163                         }
 164                         else {
 165                                 UFSD(("EXIT\n"))
 166                                 return sb->u.ufs_sb.s_ucpi[cgno];
 167                         }
 168                 } else {
 169                         ufs_read_cylinder (sb, cgno, cgno);
 170                         UFSD(("EXIT\n"))
 171                         return sb->u.ufs_sb.s_ucpi[cgno];
 172                 }
 173         }
 174         /*
 175          * Cylinder group number cg is in cache but it was not last used,
 176          * we will move to the first position
 177          */
 178         for (i = 0; i < sb->u.ufs_sb.s_cg_loaded && sb->u.ufs_sb.s_cgno[i] != cgno; i++);
 179         if (i < sb->u.ufs_sb.s_cg_loaded && sb->u.ufs_sb.s_cgno[i] == cgno) {
 180                 cg = sb->u.ufs_sb.s_cgno[i];
 181                 ucpi = sb->u.ufs_sb.s_ucpi[i];
 182                 for (j = i; j > 0; j--) {
 183                         sb->u.ufs_sb.s_cgno[j] = sb->u.ufs_sb.s_cgno[j-1];
 184                         sb->u.ufs_sb.s_ucpi[j] = sb->u.ufs_sb.s_ucpi[j-1];
 185                 }
 186                 sb->u.ufs_sb.s_cgno[0] = cg;
 187                 sb->u.ufs_sb.s_ucpi[0] = ucpi;
 188         /*
 189          * Cylinder group number cg is not in cache, we will read it from disk
 190          * and put it to the first position
 191          */
 192         } else {
 193                 if (sb->u.ufs_sb.s_cg_loaded < UFS_MAX_GROUP_LOADED)
 194                         sb->u.ufs_sb.s_cg_loaded++;
 195                 else
 196                         ufs_put_cylinder (sb, UFS_MAX_GROUP_LOADED-1);
 197                 ucpi = sb->u.ufs_sb.s_ucpi[sb->u.ufs_sb.s_cg_loaded - 1];
 198                 for (j = sb->u.ufs_sb.s_cg_loaded - 1; j > 0; j--) {
 199                         sb->u.ufs_sb.s_cgno[j] = sb->u.ufs_sb.s_cgno[j-1];
 200                         sb->u.ufs_sb.s_ucpi[j] = sb->u.ufs_sb.s_ucpi[j-1];
 201                 }
 202                 sb->u.ufs_sb.s_ucpi[0] = ucpi;
 203                 ufs_read_cylinder (sb, cgno, 0);
 204         }
 205         UFSD(("EXIT\n"))
 206         return sb->u.ufs_sb.s_ucpi[0];
 207 }