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