fs/xiafs/bitmap.c

/* */
This source file includes following definitions.
find_first_zero
clear_buf
que
get__map_zone
get_free__bit
xiafs_free_zone
xiafs_new_zone
xiafs_free_inode
xiafs_new_inode
count_zone
xiafs_count_free_inodes
xiafs_count_free_zones
   1 /*
   2  *  linux/fs/xiafs/bitmap.c
   3  *
   4  *  Copyright (C) Q. Frank Xia, 1993.
   5  *  
   6  *  Based on Linus' minix/bitmap.c
   7  *  Copyright (C) Linus Torvalds, 1991, 1992.
   8  *  
   9  *  This software may be redistributed per Linux Copyright.
  10  */
  11 
  12 /* bitmap.c contains the code that handles the inode and block bitmaps */
  13 
  14 #include <linux/sched.h>
  15 #include <linux/locks.h>
  16 #include <linux/xia_fs.h>
  17 #include <linux/stat.h>
  18 #include <linux/kernel.h>
  19 #include <linux/string.h>
  20 
  21 #include <asm/bitops.h>
  22 
  23 #include "xiafs_mac.h"
  24 
  25 
  26 char internal_error_message[]="XIA-FS: internal error %s %d\n"; 
  27 
  28 static int find_first_zero(struct buffer_head *bh, int start_bit, int end_bit) 
     /*  */
  29 {
  30     /* This routine searches first 0 bit from (start_bit) to (end_bit-1).
  31      * If found the bit is set to 1 and the bit # is returned, otherwise,
  32      * -1 is returned. Race condition is avoid by using "btsl" and 
  33      * "goto repeat".  ---Frank.
  34      */
  35 
  36     int end, i, j, tmp;
  37     u_long *bmap;
  38     char res;
  39 
  40     bmap=(u_long *)bh->b_data;
  41     end = end_bit >> 5;
  42 
  43 repeat:
  44     i=start_bit >> 5;
  45     if ( (tmp=(~bmap[i]) & (0xffffffff << (start_bit & 31))) )        
  46         goto zone_found;
  47     while (++i < end)
  48         if (~bmap[i]) {
  49             tmp=~bmap[i];
  50             goto zone_found;
  51         }
  52     if ( !(tmp=~bmap[i] & ((1 << (end_bit & 31)) -1)) )
  53         return -1;
  54 zone_found:    
  55     for (j=0; j < 32; j++)
  56         if (tmp & (1 << j))
  57             break;
  58     if (set_bit(j,bmap+i)) {
  59         start_bit=j + (i << 5) + 1;
  60         goto repeat;
  61     }
  62     mark_buffer_dirty(bh, 1);
  63     return j + (i << 5);
  64 }
  65 
  66 static void clear_buf(struct buffer_head * bh) 
     /*  */
  67 {
  68     register int i;
  69     register long * lp;
  70 
  71     lp=(long *)bh->b_data;
  72     for (i= bh->b_size >> 2; i-- > 0; )
  73         *lp++=0;
  74 }
  75 
  76 static void que(struct buffer_head * bmap[], int bznr[], int pos)
     /*  */
  77 {
  78     struct buffer_head * tbh;
  79     int tmp;
  80     int i;
  81     
  82     tbh=bmap[pos];
  83     tmp=bznr[pos];
  84     for (i=pos; i > 0; i--) {
  85         bmap[i]=bmap[i-1];
  86         bznr[i]=bznr[i-1];
  87     }
  88     bmap[0]=tbh;
  89     bznr[0]=tmp;
  90 }
  91 
  92 #define get_imap_zone(sb, bit_nr, not_que) \
  93         get__map_zone((sb), (sb)->u.xiafs_sb.s_imap_buf, \
  94                       (sb)->u.xiafs_sb.s_imap_iznr, \
  95                       (sb)->u.xiafs_sb.s_imap_cached, 1, \
  96                       (sb)->u.xiafs_sb.s_imap_zones, _XIAFS_IMAP_SLOTS, \
  97                       bit_nr, not_que)
  98 
  99 #define get_zmap_zone(sb, bit_nr, not_que) \
 100         get__map_zone((sb), (sb)->u.xiafs_sb.s_zmap_buf, \
 101                       (sb)->u.xiafs_sb.s_zmap_zznr, \
 102                       (sb)->u.xiafs_sb.s_zmap_cached, \
 103                       1+(sb)->u.xiafs_sb.s_imap_zones, \
 104                       (sb)->u.xiafs_sb.s_zmap_zones, _XIAFS_ZMAP_SLOTS, \
 105                       bit_nr, not_que)
 106 
 107 static struct buffer_head * 
 108 get__map_zone(struct super_block *sb, struct buffer_head * bmap_buf[],
     /*  */
 109           int bznr[], u_char cache, int first_zone, 
 110           int bmap_zones, int slots, u_long bit_nr, int * not_que)
 111 {
 112     struct buffer_head * tmp_bh;
 113     int z_nr, i;
 114 
 115     z_nr = bit_nr >> XIAFS_BITS_PER_Z_BITS(sb);
 116     if (z_nr >= bmap_zones) {
 117         printk("XIA-FS: bad inode/zone number (%s %d)\n", WHERE_ERR);
 118         return NULL;
 119     }
 120     if (!cache)
 121         return bmap_buf[z_nr];
 122     lock_super(sb);
 123     for (i=0; i < slots; i++) 
 124         if (bznr[i]==z_nr)
 125             break;
 126     if (i < slots) {                    /* cache hit */
 127         if (not_que) {
 128             *not_que=i;
 129             return bmap_buf[i];
 130         } else {
 131             que(bmap_buf, bznr, i);
 132             return bmap_buf[0];
 133         }
 134     }
 135     tmp_bh=bread(sb->s_dev, z_nr+first_zone, XIAFS_ZSIZE(sb)); /* cache not hit */
 136     if (!tmp_bh) {
 137         printk("XIA-FS: read bitmap failed (%s %d)\n", WHERE_ERR);
 138         unlock_super(sb);
 139         return NULL;
 140     }
 141     brelse(bmap_buf[slots-1]);
 142     bmap_buf[slots-1]=tmp_bh;
 143     bznr[slots-1]=z_nr;
 144     if (not_que)
 145         *not_que=slots-1;
 146     else
 147         que(bmap_buf, bznr, slots-1);
 148     return tmp_bh;
 149 }
 150 
 151 #define xiafs_unlock_super(sb, cache)   if (cache) unlock_super(sb);
 152 
 153 #define get_free_ibit(sb, prev_bit) \
 154         get_free__bit(sb, sb->u.xiafs_sb.s_imap_buf, \
 155                       sb->u.xiafs_sb.s_imap_iznr, \
 156                       sb->u.xiafs_sb.s_imap_cached, \
 157                       1, sb->u.xiafs_sb.s_imap_zones, \
 158                       _XIAFS_IMAP_SLOTS, prev_bit);
 159 
 160 #define get_free_zbit(sb, prev_bit) \
 161         get_free__bit(sb, sb->u.xiafs_sb.s_zmap_buf, \
 162                       sb->u.xiafs_sb.s_zmap_zznr, \
 163                       sb->u.xiafs_sb.s_zmap_cached, \
 164                       1 + sb->u.xiafs_sb.s_imap_zones, \
 165                       sb->u.xiafs_sb.s_zmap_zones, \
 166                       _XIAFS_ZMAP_SLOTS, prev_bit);
 167 
 168 static u_long 
 169 get_free__bit(struct super_block *sb, struct buffer_head * bmap_buf[],
     /*  */
 170               int bznr[], u_char cache, int first_zone, int bmap_zones, 
 171               int slots, u_long prev_bit)
 172 {
 173     struct buffer_head * bh;
 174     int not_done=0;
 175     u_long pos, start_bit, end_bit, total_bits;
 176     int z_nr, tmp;
 177  
 178     total_bits=bmap_zones << XIAFS_BITS_PER_Z_BITS(sb); 
 179     if (prev_bit >= total_bits)
 180         prev_bit=0;
 181     pos=prev_bit+1;
 182     end_bit=XIAFS_BITS_PER_Z(sb);
 183 
 184     do {
 185         if (pos >= total_bits)
 186             pos=0;
 187         if (!not_done) {                /* first time */
 188             not_done=1;
 189             start_bit= pos & (end_bit-1);     
 190         } else 
 191             start_bit=0;
 192         if ( pos < prev_bit && pos+end_bit >= prev_bit) {   /* last time */
 193             not_done=0;
 194             end_bit=prev_bit & (end_bit-1);   /* only here end_bit modified */
 195         }
 196         bh = get__map_zone(sb, bmap_buf, bznr, cache, first_zone, 
 197                            bmap_zones, slots, pos, &z_nr);
 198         if (!bh)
 199             return 0;
 200         tmp=find_first_zero(bh, start_bit, end_bit);
 201         if (tmp >= 0)
 202             break;
 203         xiafs_unlock_super(sb, sb->u.xiafs_sb.s_zmap_cached);
 204         pos=(pos & ~(end_bit-1))+end_bit;
 205     } while (not_done);
 206 
 207     if (tmp < 0) 
 208         return 0;
 209     if (cache)
 210       que(bmap_buf, bznr, z_nr);
 211     xiafs_unlock_super(sb, cache);
 212     return (pos & ~(XIAFS_BITS_PER_Z(sb)-1))+tmp;
 213 }
 214 
 215 void xiafs_free_zone(struct super_block * sb, int d_addr)
     /*  */
 216 {
 217     struct buffer_head * bh;
 218     unsigned int bit, offset;
 219 
 220     if (!sb) {
 221         printk(INTERN_ERR);
 222         return;
 223     }
 224     if (d_addr < sb->u.xiafs_sb.s_firstdatazone ||
 225         d_addr >= sb->u.xiafs_sb.s_nzones) {
 226         printk("XIA-FS: bad zone number (%s %d)\n", WHERE_ERR);
 227         return;
 228     }
 229     bh = get_hash_table(sb->s_dev, d_addr, XIAFS_ZSIZE(sb));
 230     if (bh)
 231         bh->b_dirt=0;
 232     brelse(bh);
 233     bit=d_addr - sb->u.xiafs_sb.s_firstdatazone + 1;
 234     bh = get_zmap_zone(sb, bit, NULL);
 235     if (!bh)
 236         return;
 237     offset = bit & (XIAFS_BITS_PER_Z(sb) -1);
 238     if (!clear_bit(offset, bh->b_data))
 239         printk("XIA-FS: dev %04x"
 240                " block bit %u (0x%x) already cleared (%s %d)\n",
 241                sb->s_dev, bit, bit, WHERE_ERR);
 242     mark_buffer_dirty(bh, 1);
 243     xiafs_unlock_super(sb, sb->u.xiafs_sb.s_zmap_cached);
 244 }
 245 
 246 int xiafs_new_zone(struct super_block * sb, u_long prev_addr)
     /*  */
 247 {
 248     struct buffer_head * bh;
 249     int prev_znr, tmp;
 250 
 251     if (!sb) {
 252         printk(INTERN_ERR);
 253         return 0;
 254     }
 255     if (prev_addr < sb->u.xiafs_sb.s_firstdatazone || 
 256         prev_addr >= sb->u.xiafs_sb.s_nzones) {
 257         prev_addr=sb->u.xiafs_sb.s_firstdatazone;
 258     }      
 259     prev_znr=prev_addr-sb->u.xiafs_sb.s_firstdatazone+1;
 260     tmp=get_free_zbit(sb, prev_znr);
 261     if (!tmp)
 262         return 0;
 263     tmp += sb->u.xiafs_sb.s_firstdatazone -1;
 264     if (!(bh = getblk(sb->s_dev, tmp, XIAFS_ZSIZE(sb)))) {
 265         printk("XIA-FS: I/O error (%s %d)\n", WHERE_ERR);
 266         return 0;
 267     }
 268     if (bh->b_count != 1) {
 269         printk(INTERN_ERR);
 270         return 0;
 271     }
 272     clear_buf(bh);
 273     bh->b_uptodate = 1;
 274     mark_buffer_dirty(bh, 1);
 275     brelse(bh);
 276     return tmp;
 277 }
 278 
 279 void xiafs_free_inode(struct inode * inode)
     /*  */
 280 {
 281     struct buffer_head * bh;
 282     struct super_block * sb;
 283     unsigned long ino;
 284 
 285     if (!inode)
 286         return;
 287     if (!inode->i_dev || inode->i_count!=1 || inode->i_nlink || !inode->i_sb ||
 288         inode->i_ino < 3 || inode->i_ino > inode->i_sb->u.xiafs_sb.s_ninodes) {
 289         printk("XIA-FS: bad inode (%s %d)\n", WHERE_ERR);
 290         return;
 291     }
 292     sb = inode->i_sb;
 293     ino = inode->i_ino;
 294     bh = get_imap_zone(sb, ino, NULL);
 295     if (!bh)
 296         return;
 297     clear_inode(inode);
 298     if (!clear_bit(ino & (XIAFS_BITS_PER_Z(sb)-1), bh->b_data))
 299         printk("XIA-FS: dev %04x"
 300                "inode bit %ld (0x%lx) already cleared (%s %d)\n",
 301                inode->i_dev, ino, ino, WHERE_ERR);
 302     mark_buffer_dirty(bh, 1);
 303     xiafs_unlock_super(sb, sb->u.xiafs_sb.s_imap_cached);
 304 }
 305 
 306 struct inode * xiafs_new_inode(struct inode * dir)
     /*  */
 307 {
 308     struct super_block * sb;
 309     struct inode * inode;
 310     ino_t tmp;
 311 
 312     sb = dir->i_sb;
 313     if (!dir || !(inode = get_empty_inode()))
 314         return NULL;
 315     inode->i_sb = sb;
 316     inode->i_flags = inode->i_sb->s_flags;
 317 
 318     tmp=get_free_ibit(sb, dir->i_ino); 
 319     if (!tmp) {
 320         iput(inode);
 321         return NULL;
 322     }
 323     inode->i_count = 1;
 324     inode->i_nlink = 1;
 325     inode->i_dev = sb->s_dev;
 326     inode->i_uid = current->fsuid;
 327     inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
 328     inode->i_dirt = 1;
 329     inode->i_ino = tmp;
 330     inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 331     inode->i_op = NULL;
 332     inode->i_blocks = 0;
 333     inode->i_blksize = XIAFS_ZSIZE(inode->i_sb);
 334     insert_inode_hash(inode);
 335     return inode;
 336 }
 337 
 338 static int nibblemap[] = { 0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4 };
 339 
 340 static u_long count_zone(struct buffer_head * bh)
     /*  */
 341 {
 342     int i, tmp;
 343     u_long sum;
 344 
 345     sum=0;
 346     for (i=bh->b_size; i-- > 0; ) {
 347         tmp=bh->b_data[i];
 348         sum += nibblemap[tmp & 0xf] + nibblemap[(tmp & 0xff) >> 4];
 349     }
 350     return sum;
 351 } 
 352 
 353 unsigned long xiafs_count_free_inodes(struct super_block *sb)
     /*  */
 354 {
 355     struct buffer_head * bh;
 356     int izones, i, not_que;
 357     u_long sum;
 358 
 359     sum=0;
 360     izones=sb->u.xiafs_sb.s_imap_zones;
 361     for (i=0; i < izones; i++) {
 362         bh=get_imap_zone(sb, i << XIAFS_BITS_PER_Z_BITS(sb), &not_que);
 363         if (bh) {
 364             sum += count_zone(bh);
 365             xiafs_unlock_super(sb, sb->u.xiafs_sb.s_imap_cached);
 366         }
 367     }
 368     i=izones << XIAFS_BITS_PER_Z_BITS(sb);
 369     return i - sum;
 370 }
 371 
 372 unsigned long xiafs_count_free_zones(struct super_block *sb)
     /*  */
 373 {
 374     struct buffer_head * bh;
 375     int zzones, i, not_que;
 376     u_long sum;
 377 
 378     sum=0;
 379     zzones=sb->u.xiafs_sb.s_zmap_zones;
 380     for (i=0; i < zzones; i++) {
 381         bh=get_zmap_zone(sb, i << XIAFS_BITS_PER_Z_BITS(sb), &not_que);
 382         if (bh) {
 383             sum += count_zone(bh);
 384             xiafs_unlock_super(sb, sb->u.xiafs_sb.s_zmap_cached);
 385         }
 386     }
 387     i=zzones << XIAFS_BITS_PER_Z_BITS(sb);
 388     return i - sum;
 389 }
/* */
root/fs/xiafs/bitmap.c

DEFINITIONS
