Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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<BLOCK_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)*BLOCK_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, int 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 | unsigned int bit,zone; |
| 57 | |
| 58 | if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) { |
Denis Vlasenko | 11b8448 | 2006-03-25 03:07:42 -0800 | [diff] [blame] | 59 | printk("Trying to free block not in datazone\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 60 | return; |
| 61 | } |
| 62 | zone = block - sbi->s_firstdatazone + 1; |
| 63 | bit = zone & 8191; |
| 64 | zone >>= 13; |
| 65 | if (zone >= sbi->s_zmap_blocks) { |
| 66 | printk("minix_free_block: nonexistent bitmap buffer\n"); |
| 67 | return; |
| 68 | } |
| 69 | bh = sbi->s_zmap[zone]; |
| 70 | lock_kernel(); |
| 71 | if (!minix_test_and_clear_bit(bit,bh->b_data)) |
| 72 | printk("free_block (%s:%d): bit already cleared\n", |
| 73 | sb->s_id, block); |
| 74 | unlock_kernel(); |
| 75 | mark_buffer_dirty(bh); |
| 76 | return; |
| 77 | } |
| 78 | |
| 79 | int minix_new_block(struct inode * inode) |
| 80 | { |
| 81 | struct minix_sb_info *sbi = minix_sb(inode->i_sb); |
| 82 | int i; |
| 83 | |
| 84 | for (i = 0; i < sbi->s_zmap_blocks; i++) { |
| 85 | struct buffer_head *bh = sbi->s_zmap[i]; |
| 86 | int j; |
| 87 | |
| 88 | lock_kernel(); |
| 89 | if ((j = minix_find_first_zero_bit(bh->b_data, 8192)) < 8192) { |
| 90 | minix_set_bit(j,bh->b_data); |
| 91 | unlock_kernel(); |
| 92 | mark_buffer_dirty(bh); |
| 93 | j += i*8192 + sbi->s_firstdatazone-1; |
| 94 | if (j < sbi->s_firstdatazone || j >= sbi->s_nzones) |
| 95 | break; |
| 96 | return j; |
| 97 | } |
| 98 | unlock_kernel(); |
| 99 | } |
| 100 | return 0; |
| 101 | } |
| 102 | |
| 103 | unsigned long minix_count_free_blocks(struct minix_sb_info *sbi) |
| 104 | { |
| 105 | return (count_free(sbi->s_zmap, sbi->s_zmap_blocks, |
| 106 | sbi->s_nzones - sbi->s_firstdatazone + 1) |
| 107 | << sbi->s_log_zone_size); |
| 108 | } |
| 109 | |
| 110 | struct minix_inode * |
| 111 | minix_V1_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh) |
| 112 | { |
| 113 | int block; |
| 114 | struct minix_sb_info *sbi = minix_sb(sb); |
| 115 | struct minix_inode *p; |
| 116 | |
| 117 | if (!ino || ino > sbi->s_ninodes) { |
| 118 | printk("Bad inode number on dev %s: %ld is out of range\n", |
| 119 | sb->s_id, (long)ino); |
| 120 | return NULL; |
| 121 | } |
| 122 | ino--; |
| 123 | block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks + |
| 124 | ino / MINIX_INODES_PER_BLOCK; |
| 125 | *bh = sb_bread(sb, block); |
| 126 | if (!*bh) { |
Denis Vlasenko | 11b8448 | 2006-03-25 03:07:42 -0800 | [diff] [blame] | 127 | printk("Unable to read inode block\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | return NULL; |
| 129 | } |
| 130 | p = (void *)(*bh)->b_data; |
| 131 | return p + ino % MINIX_INODES_PER_BLOCK; |
| 132 | } |
| 133 | |
| 134 | struct minix2_inode * |
| 135 | minix_V2_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh) |
| 136 | { |
| 137 | int block; |
| 138 | struct minix_sb_info *sbi = minix_sb(sb); |
| 139 | struct minix2_inode *p; |
| 140 | |
| 141 | *bh = NULL; |
| 142 | if (!ino || ino > sbi->s_ninodes) { |
| 143 | printk("Bad inode number on dev %s: %ld is out of range\n", |
| 144 | sb->s_id, (long)ino); |
| 145 | return NULL; |
| 146 | } |
| 147 | ino--; |
| 148 | block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks + |
| 149 | ino / MINIX2_INODES_PER_BLOCK; |
| 150 | *bh = sb_bread(sb, block); |
| 151 | if (!*bh) { |
Denis Vlasenko | 11b8448 | 2006-03-25 03:07:42 -0800 | [diff] [blame] | 152 | printk("Unable to read inode block\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 153 | return NULL; |
| 154 | } |
| 155 | p = (void *)(*bh)->b_data; |
| 156 | return p + ino % MINIX2_INODES_PER_BLOCK; |
| 157 | } |
| 158 | |
| 159 | /* Clear the link count and mode of a deleted inode on disk. */ |
| 160 | |
| 161 | static void minix_clear_inode(struct inode *inode) |
| 162 | { |
| 163 | struct buffer_head *bh = NULL; |
| 164 | |
| 165 | if (INODE_VERSION(inode) == MINIX_V1) { |
| 166 | struct minix_inode *raw_inode; |
| 167 | raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh); |
| 168 | if (raw_inode) { |
| 169 | raw_inode->i_nlinks = 0; |
| 170 | raw_inode->i_mode = 0; |
| 171 | } |
| 172 | } else { |
| 173 | struct minix2_inode *raw_inode; |
| 174 | raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh); |
| 175 | if (raw_inode) { |
| 176 | raw_inode->i_nlinks = 0; |
| 177 | raw_inode->i_mode = 0; |
| 178 | } |
| 179 | } |
| 180 | if (bh) { |
| 181 | mark_buffer_dirty(bh); |
| 182 | brelse (bh); |
| 183 | } |
| 184 | } |
| 185 | |
| 186 | void minix_free_inode(struct inode * inode) |
| 187 | { |
| 188 | struct minix_sb_info *sbi = minix_sb(inode->i_sb); |
| 189 | struct buffer_head * bh; |
| 190 | unsigned long ino; |
| 191 | |
| 192 | ino = inode->i_ino; |
| 193 | if (ino < 1 || ino > sbi->s_ninodes) { |
| 194 | printk("minix_free_inode: inode 0 or nonexistent inode\n"); |
| 195 | goto out; |
| 196 | } |
| 197 | if ((ino >> 13) >= sbi->s_imap_blocks) { |
| 198 | printk("minix_free_inode: nonexistent imap in superblock\n"); |
| 199 | goto out; |
| 200 | } |
| 201 | |
| 202 | minix_clear_inode(inode); /* clear on-disk copy */ |
| 203 | |
| 204 | bh = sbi->s_imap[ino >> 13]; |
| 205 | lock_kernel(); |
| 206 | if (!minix_test_and_clear_bit(ino & 8191, bh->b_data)) |
Denis Vlasenko | 11b8448 | 2006-03-25 03:07:42 -0800 | [diff] [blame] | 207 | printk("minix_free_inode: bit %lu already cleared\n", ino); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 208 | unlock_kernel(); |
| 209 | mark_buffer_dirty(bh); |
| 210 | out: |
| 211 | clear_inode(inode); /* clear in-memory copy */ |
| 212 | } |
| 213 | |
| 214 | struct inode * minix_new_inode(const struct inode * dir, int * error) |
| 215 | { |
| 216 | struct super_block *sb = dir->i_sb; |
| 217 | struct minix_sb_info *sbi = minix_sb(sb); |
| 218 | struct inode *inode = new_inode(sb); |
| 219 | struct buffer_head * bh; |
| 220 | int i,j; |
| 221 | |
| 222 | if (!inode) { |
| 223 | *error = -ENOMEM; |
| 224 | return NULL; |
| 225 | } |
| 226 | j = 8192; |
| 227 | bh = NULL; |
| 228 | *error = -ENOSPC; |
| 229 | lock_kernel(); |
| 230 | for (i = 0; i < sbi->s_imap_blocks; i++) { |
| 231 | bh = sbi->s_imap[i]; |
| 232 | if ((j = minix_find_first_zero_bit(bh->b_data, 8192)) < 8192) |
| 233 | break; |
| 234 | } |
| 235 | if (!bh || j >= 8192) { |
| 236 | unlock_kernel(); |
| 237 | iput(inode); |
| 238 | return NULL; |
| 239 | } |
| 240 | if (minix_test_and_set_bit(j,bh->b_data)) { /* shouldn't happen */ |
Denis Vlasenko | 11b8448 | 2006-03-25 03:07:42 -0800 | [diff] [blame] | 241 | printk("new_inode: bit already set\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 242 | unlock_kernel(); |
| 243 | iput(inode); |
| 244 | return NULL; |
| 245 | } |
| 246 | unlock_kernel(); |
| 247 | mark_buffer_dirty(bh); |
| 248 | j += i*8192; |
| 249 | if (!j || j > sbi->s_ninodes) { |
| 250 | iput(inode); |
| 251 | return NULL; |
| 252 | } |
| 253 | inode->i_uid = current->fsuid; |
| 254 | inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid; |
| 255 | inode->i_ino = j; |
| 256 | inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC; |
| 257 | inode->i_blocks = inode->i_blksize = 0; |
| 258 | memset(&minix_i(inode)->u, 0, sizeof(minix_i(inode)->u)); |
| 259 | insert_inode_hash(inode); |
| 260 | mark_inode_dirty(inode); |
| 261 | |
| 262 | *error = 0; |
| 263 | return inode; |
| 264 | } |
| 265 | |
| 266 | unsigned long minix_count_free_inodes(struct minix_sb_info *sbi) |
| 267 | { |
| 268 | return count_free(sbi->s_imap, sbi->s_imap_blocks, sbi->s_ninodes + 1); |
| 269 | } |