1 /* 2 * linux/fs/minix/bitmap.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 */ 6 7 /* 8 * Modified for 680x0 by Hamish Macdonald 9 * Fixed for 680x0 by Andreas Schwab 10 */ 11 12 /* bitmap.c contains the code that handles the inode and block bitmaps */ 13 14 #include "minix.h" 15 #include <linux/smp_lock.h> 16 #include <linux/buffer_head.h> 17 #include <linux/bitops.h> 18 19 static int nibblemap[] = { 4,3,3,2,3,2,2,1,3,2,2,1,2,1,1,0 }; 20 21 static unsigned long count_free(struct buffer_head *map[], unsigned numblocks, __u32 numbits) 22 { 23 unsigned i, j, sum = 0; 24 struct buffer_head *bh; 25 26 for (i=0; i<numblocks-1; i++) { 27 if (!(bh=map[i])) 28 return(0); 29 for (j=0; j<bh->b_size; j++) 30 sum += nibblemap[bh->b_data[j] & 0xf] 31 + nibblemap[(bh->b_data[j]>>4) & 0xf]; 32 } 33 34 if (numblocks==0 || !(bh=map[numblocks-1])) 35 return(0); 36 i = ((numbits - (numblocks-1) * bh->b_size * 8) / 16) * 2; 37 for (j=0; j<i; j++) { 38 sum += nibblemap[bh->b_data[j] & 0xf] 39 + nibblemap[(bh->b_data[j]>>4) & 0xf]; 40 } 41 42 i = numbits%16; 43 if (i!=0) { 44 i = *(__u16 *)(&bh->b_data[j]) | ~((1<<i) - 1); 45 sum += nibblemap[i & 0xf] + nibblemap[(i>>4) & 0xf]; 46 sum += nibblemap[(i>>8) & 0xf] + nibblemap[(i>>12) & 0xf]; 47 } 48 return(sum); 49 } 50 51 void minix_free_block(struct inode *inode, unsigned long block) 52 { 53 struct super_block *sb = inode->i_sb; 54 struct minix_sb_info *sbi = minix_sb(sb); 55 struct buffer_head *bh; 56 int k = sb->s_blocksize_bits + 3; 57 unsigned long bit, zone; 58 59 if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) { 60 printk("Trying to free block not in datazone\n"); 61 return; 62 } 63 zone = block - sbi->s_firstdatazone + 1; 64 bit = zone & ((1<<k) - 1); 65 zone >>= k; 66 if (zone >= sbi->s_zmap_blocks) { 67 printk("minix_free_block: nonexistent bitmap buffer\n"); 68 return; 69 } 70 bh = sbi->s_zmap[zone]; 71 lock_kernel(); 72 if (!minix_test_and_clear_bit(bit, bh->b_data)) 73 printk("minix_free_block (%s:%lu): bit already cleared\n", 74 sb->s_id, block); 75 unlock_kernel(); 76 mark_buffer_dirty(bh); 77 return; 78 } 79 80 int minix_new_block(struct inode * inode) 81 { 82 struct minix_sb_info *sbi = minix_sb(inode->i_sb); 83 int bits_per_zone = 8 * inode->i_sb->s_blocksize; 84 int i; 85 86 for (i = 0; i < sbi->s_zmap_blocks; i++) { 87 struct buffer_head *bh = sbi->s_zmap[i]; 88 int j; 89 90 lock_kernel(); 91 j = minix_find_first_zero_bit(bh->b_data, bits_per_zone); 92 if (j < bits_per_zone) { 93 minix_set_bit(j, bh->b_data); 94 unlock_kernel(); 95 mark_buffer_dirty(bh); 96 j += i * bits_per_zone + sbi->s_firstdatazone-1; 97 if (j < sbi->s_firstdatazone || j >= sbi->s_nzones) 98 break; 99 return j; 100 } 101 unlock_kernel(); 102 } 103 return 0; 104 } 105 106 unsigned long minix_count_free_blocks(struct minix_sb_info *sbi) 107 { 108 return (count_free(sbi->s_zmap, sbi->s_zmap_blocks, 109 sbi->s_nzones - sbi->s_firstdatazone + 1) 110 << sbi->s_log_zone_size); 111 } 112 113 struct minix_inode * 114 minix_V1_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh) 115 { 116 int block; 117 struct minix_sb_info *sbi = minix_sb(sb); 118 struct minix_inode *p; 119 120 if (!ino || ino > sbi->s_ninodes) { 121 printk("Bad inode number on dev %s: %ld is out of range\n", 122 sb->s_id, (long)ino); 123 return NULL; 124 } 125 ino--; 126 block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks + 127 ino / MINIX_INODES_PER_BLOCK; 128 *bh = sb_bread(sb, block); 129 if (!*bh) { 130 printk("Unable to read inode block\n"); 131 return NULL; 132 } 133 p = (void *)(*bh)->b_data; 134 return p + ino % MINIX_INODES_PER_BLOCK; 135 } 136 137 struct minix2_inode * 138 minix_V2_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh) 139 { 140 int block; 141 struct minix_sb_info *sbi = minix_sb(sb); 142 struct minix2_inode *p; 143 int minix2_inodes_per_block = sb->s_blocksize / sizeof(struct minix2_inode); 144 145 *bh = NULL; 146 if (!ino || ino > sbi->s_ninodes) { 147 printk("Bad inode number on dev %s: %ld is out of range\n", 148 sb->s_id, (long)ino); 149 return NULL; 150 } 151 ino--; 152 block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks + 153 ino / minix2_inodes_per_block; 154 *bh = sb_bread(sb, block); 155 if (!*bh) { 156 printk("Unable to read inode block\n"); 157 return NULL; 158 } 159 p = (void *)(*bh)->b_data; 160 return p + ino % minix2_inodes_per_block; 161 } 162 163 /* Clear the link count and mode of a deleted inode on disk. */ 164 165 static void minix_clear_inode(struct inode *inode) 166 { 167 struct buffer_head *bh = NULL; 168 169 if (INODE_VERSION(inode) == MINIX_V1) { 170 struct minix_inode *raw_inode; 171 raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh); 172 if (raw_inode) { 173 raw_inode->i_nlinks = 0; 174 raw_inode->i_mode = 0; 175 } 176 } else { 177 struct minix2_inode *raw_inode; 178 raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh); 179 if (raw_inode) { 180 raw_inode->i_nlinks = 0; 181 raw_inode->i_mode = 0; 182 } 183 } 184 if (bh) { 185 mark_buffer_dirty(bh); 186 brelse (bh); 187 } 188 } 189 190 void minix_free_inode(struct inode * inode) 191 { 192 struct super_block *sb = inode->i_sb; 193 struct minix_sb_info *sbi = minix_sb(inode->i_sb); 194 struct buffer_head *bh; 195 int k = sb->s_blocksize_bits + 3; 196 unsigned long ino, bit; 197 198 ino = inode->i_ino; 199 if (ino < 1 || ino > sbi->s_ninodes) { 200 printk("minix_free_inode: inode 0 or nonexistent inode\n"); 201 goto out; 202 } 203 bit = ino & ((1<<k) - 1); 204 ino >>= k; 205 if (ino >= sbi->s_imap_blocks) { 206 printk("minix_free_inode: nonexistent imap in superblock\n"); 207 goto out; 208 } 209 210 minix_clear_inode(inode); /* clear on-disk copy */ 211 212 bh = sbi->s_imap[ino]; 213 lock_kernel(); 214 if (!minix_test_and_clear_bit(bit, bh->b_data)) 215 printk("minix_free_inode: bit %lu already cleared\n", bit); 216 unlock_kernel(); 217 mark_buffer_dirty(bh); 218 out: 219 clear_inode(inode); /* clear in-memory copy */ 220 } 221 222 struct inode * minix_new_inode(const struct inode * dir, int * error) 223 { 224 struct super_block *sb = dir->i_sb; 225 struct minix_sb_info *sbi = minix_sb(sb); 226 struct inode *inode = new_inode(sb); 227 struct buffer_head * bh; 228 int bits_per_zone = 8 * sb->s_blocksize; 229 unsigned long j; 230 int i; 231 232 if (!inode) { 233 *error = -ENOMEM; 234 return NULL; 235 } 236 j = bits_per_zone; 237 bh = NULL; 238 *error = -ENOSPC; 239 lock_kernel(); 240 for (i = 0; i < sbi->s_imap_blocks; i++) { 241 bh = sbi->s_imap[i]; 242 j = minix_find_first_zero_bit(bh->b_data, bits_per_zone); 243 if (j < bits_per_zone) 244 break; 245 } 246 if (!bh || j >= bits_per_zone) { 247 unlock_kernel(); 248 iput(inode); 249 return NULL; 250 } 251 if (minix_test_and_set_bit(j, bh->b_data)) { /* shouldn't happen */ 252 unlock_kernel(); 253 printk("minix_new_inode: bit already set\n"); 254 iput(inode); 255 return NULL; 256 } 257 unlock_kernel(); 258 mark_buffer_dirty(bh); 259 j += i * bits_per_zone; 260 if (!j || j > sbi->s_ninodes) { 261 iput(inode); 262 return NULL; 263 } 264 inode->i_uid = current->fsuid; 265 inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid; 266 inode->i_ino = j; 267 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC; 268 inode->i_blocks = 0; 269 memset(&minix_i(inode)->u, 0, sizeof(minix_i(inode)->u)); 270 insert_inode_hash(inode); 271 mark_inode_dirty(inode); 272 273 *error = 0; 274 return inode; 275 } 276 277 unsigned long minix_count_free_inodes(struct minix_sb_info *sbi) 278 { 279 return count_free(sbi->s_imap, sbi->s_imap_blocks, sbi->s_ninodes + 1); 280 } 281