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 #undef UFS_CYLINDER_DEBUG 24 25 #ifdef UFS_CYLINDER_DEBUG 26 #define UFSD(x) printk("(%s, %d), %s:", __FILE__, __LINE__, __FUNCTION__); printk x; 27 #else 28 #define UFSD(x) 29 #endif 30 31 32 /* 33 * Read cylinder group into cache. The memory space for ufs_cg_private_info 34 * structure is already allocated during ufs_read_super. 35 */ 36 static void ufs_read_cylinder (struct super_block * sb, 37 unsigned cgno, unsigned bitmap_nr) 38 { 39 struct ufs_sb_info * sbi = UFS_SB(sb); 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 = sbi->s_uspi; 47 ucpi = sbi->s_ucpi[bitmap_nr]; 48 ucg = (struct ufs_cylinder_group *)sbi->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] = sbi->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 sbi->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 (sbi->s_ucg[j]); 82 sbi->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_info * sbi = UFS_SB(sb); 93 struct ufs_sb_private_info * uspi; 94 struct ufs_cg_private_info * ucpi; 95 struct ufs_cylinder_group * ucg; 96 unsigned i; 97 98 UFSD(("ENTER, bitmap_nr %u\n", bitmap_nr)) 99 100 uspi = sbi->s_uspi; 101 if (sbi->s_cgno[bitmap_nr] == UFS_CGNO_EMPTY) { 102 UFSD(("EXIT\n")) 103 return; 104 } 105 ucpi = sbi->s_ucpi[bitmap_nr]; 106 ucg = ubh_get_ucg(UCPI_UBH); 107 108 if (uspi->s_ncg > UFS_MAX_GROUP_LOADED && bitmap_nr >= sbi->s_cg_loaded) { 109 ufs_panic (sb, "ufs_put_cylinder", "internal error"); 110 return; 111 } 112 /* 113 * rotor is not so important data, so we put it to disk 114 * at the end of working with cylinder 115 */ 116 ucg->cg_rotor = cpu_to_fs32(sb, ucpi->c_rotor); 117 ucg->cg_frotor = cpu_to_fs32(sb, ucpi->c_frotor); 118 ucg->cg_irotor = cpu_to_fs32(sb, ucpi->c_irotor); 119 ubh_mark_buffer_dirty (UCPI_UBH); 120 for (i = 1; i < UCPI_UBH->count; i++) { 121 brelse (UCPI_UBH->bh[i]); 122 } 123 124 sbi->s_cgno[bitmap_nr] = UFS_CGNO_EMPTY; 125 UFSD(("EXIT\n")) 126 } 127 128 /* 129 * Find cylinder group in cache and return it as pointer. 130 * If cylinder group is not in cache, we will load it from disk. 131 * 132 * The cache is managed by LRU algorithm. 133 */ 134 struct ufs_cg_private_info * ufs_load_cylinder ( 135 struct super_block * sb, unsigned cgno) 136 { 137 struct ufs_sb_info * sbi = UFS_SB(sb); 138 struct ufs_sb_private_info * uspi; 139 struct ufs_cg_private_info * ucpi; 140 unsigned cg, i, j; 141 142 UFSD(("ENTER, cgno %u\n", cgno)) 143 144 uspi = sbi->s_uspi; 145 if (cgno >= uspi->s_ncg) { 146 ufs_panic (sb, "ufs_load_cylinder", "internal error, high number of cg"); 147 return NULL; 148 } 149 /* 150 * Cylinder group number cg it in cache and it was last used 151 */ 152 if (sbi->s_cgno[0] == cgno) { 153 UFSD(("EXIT\n")) 154 return sbi->s_ucpi[0]; 155 } 156 /* 157 * Number of cylinder groups is not higher than UFS_MAX_GROUP_LOADED 158 */ 159 if (uspi->s_ncg <= UFS_MAX_GROUP_LOADED) { 160 if (sbi->s_cgno[cgno] != UFS_CGNO_EMPTY) { 161 if (sbi->s_cgno[cgno] != cgno) { 162 ufs_panic (sb, "ufs_load_cylinder", "internal error, wrong number of cg in cache"); 163 UFSD(("EXIT (FAILED)\n")) 164 return NULL; 165 } 166 else { 167 UFSD(("EXIT\n")) 168 return sbi->s_ucpi[cgno]; 169 } 170 } else { 171 ufs_read_cylinder (sb, cgno, cgno); 172 UFSD(("EXIT\n")) 173 return sbi->s_ucpi[cgno]; 174 } 175 } 176 /* 177 * Cylinder group number cg is in cache but it was not last used, 178 * we will move to the first position 179 */ 180 for (i = 0; i < sbi->s_cg_loaded && sbi->s_cgno[i] != cgno; i++); 181 if (i < sbi->s_cg_loaded && sbi->s_cgno[i] == cgno) { 182 cg = sbi->s_cgno[i]; 183 ucpi = sbi->s_ucpi[i]; 184 for (j = i; j > 0; j--) { 185 sbi->s_cgno[j] = sbi->s_cgno[j-1]; 186 sbi->s_ucpi[j] = sbi->s_ucpi[j-1]; 187 } 188 sbi->s_cgno[0] = cg; 189 sbi->s_ucpi[0] = ucpi; 190 /* 191 * Cylinder group number cg is not in cache, we will read it from disk 192 * and put it to the first position 193 */ 194 } else { 195 if (sbi->s_cg_loaded < UFS_MAX_GROUP_LOADED) 196 sbi->s_cg_loaded++; 197 else 198 ufs_put_cylinder (sb, UFS_MAX_GROUP_LOADED-1); 199 ucpi = sbi->s_ucpi[sbi->s_cg_loaded - 1]; 200 for (j = sbi->s_cg_loaded - 1; j > 0; j--) { 201 sbi->s_cgno[j] = sbi->s_cgno[j-1]; 202 sbi->s_ucpi[j] = sbi->s_ucpi[j-1]; 203 } 204 sbi->s_ucpi[0] = ucpi; 205 ufs_read_cylinder (sb, cgno, 0); 206 } 207 UFSD(("EXIT\n")) 208 return sbi->s_ucpi[0]; 209 } 210