fs/minix/bitmap.c

   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) {
  59                 printk("trying to free block not in datazone\n");
  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) {
 127                 printk("unable to read i-node block\n");
 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) {
 152                 printk("unable to read i-node block\n");
 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))
 207                 printk("minix_free_inode: bit %lu already cleared.\n", ino);
 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 */
 241                 printk("new_inode: bit already set");
 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 }