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