fs/hpfs/alloc.c

   1 /*
   2  *  linux/fs/hpfs/alloc.c
   3  *
   4  *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
   5  *
   6  *  HPFS bitmap operations
   7  */
   8
   9 #include "hpfs_fn.h"
  10
  11 /*
  12  * Check if a sector is allocated in bitmap
  13  * This is really slow. Turned on only if chk==2
  14  */
  15
  16 static int chk_if_allocated(struct super_block *s, secno sec, char *msg)
  17 {
  18         struct quad_buffer_head qbh;
  19         unsigned *bmp;
  20         if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "chk"))) goto fail;
  21         if ((bmp[(sec & 0x3fff) >> 5] >> (sec & 0x1f)) & 1) {
  22                 hpfs_error(s, "sector '%s' - %08x not allocated in bitmap", msg, sec);
  23                 goto fail1;
  24         }
  25         hpfs_brelse4(&qbh);
  26         if (sec >= s->s_hpfs_dirband_start && sec < s->s_hpfs_dirband_start + s->s_hpfs_dirband_size) {
  27                 unsigned ssec = (sec - s->s_hpfs_dirband_start) / 4;
  28                 if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto fail;
  29                 if ((bmp[ssec >> 5] >> (ssec & 0x1f)) & 1) {
  30                         hpfs_error(s, "sector '%s' - %08x not allocated in directory bitmap", msg, sec);
  31                         goto fail1;
  32                 }
  33                 hpfs_brelse4(&qbh);
  34         }
  35         return 0;
  36         fail1:
  37         hpfs_brelse4(&qbh);
  38         fail:
  39         return 1;
  40 }
  41
  42 /*
  43  * Check if sector(s) have proper number and additionally check if they're
  44  * allocated in bitmap.
  45  */
  46
  47 int hpfs_chk_sectors(struct super_block *s, secno start, int len, char *msg)
  48 {
  49         if (start + len < start || start < 0x12 ||
  50             start + len > s->s_hpfs_fs_size) {
  51                 hpfs_error(s, "sector(s) '%s' badly placed at %08x", msg, start);
  52                 return 1;
  53         }
  54         if (s->s_hpfs_chk>=2) {
  55                 int i;
  56                 for (i = 0; i < len; i++)
  57                         if (chk_if_allocated(s, start + i, msg)) return 1;
  58         }
  59         return 0;
  60 }
  61
  62 static secno alloc_in_bmp(struct super_block *s, secno near, unsigned n, unsigned forward)
  63 {
  64         struct quad_buffer_head qbh;
  65         unsigned *bmp;
  66         unsigned bs = near & ~0x3fff;
  67         unsigned nr = (near & 0x3fff) & ~(n - 1);
  68         /*unsigned mnr;*/
  69         unsigned i, q;
  70         int a, b;
  71         secno ret = 0;
  72         if (n != 1 && n != 4) {
  73                 hpfs_error(s, "Bad allocation size: %d", n);
  74                 return 0;
  75         }
  76         lock_super(s);
  77         if (bs != ~0x3fff) {
  78                 if (!(bmp = hpfs_map_bitmap(s, near >> 14, &qbh, "aib"))) goto uls;
  79         } else {
  80                 if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto uls;
  81         }
  82         /*if (!tstbits(bmp, nr + n, n + forward)) {
  83                 ret = bs + nr;
  84                 goto rt;
  85         }
  86         if (!tstbits(bmp, nr + 2*n, n + forward)) {
  87                 ret = bs + nr + n;
  88                 goto rt;
  89         }*/
  90         q = nr + n; b = 0;
  91         while ((a = tstbits(bmp, q, n + forward))) {
  92                 q += a;
  93                 if (n != 1) q = ((q-1)&~(n-1))+n;
  94                 if (!b) {
  95                         if (q>>5 != nr>>5) {
  96                                 b = 1;
  97                                 q = nr & 0x1f;
  98                         }
  99                 } else if (q > nr) break;
 100         }
 101         if (!a) {
 102                 ret = bs + q;
 103                 goto rt;
 104         }
 105         nr >>= 5;
 106         for (i = nr + 1; i != nr; i++, i &= 0x1ff) {
 107                 if (!bmp[i]) continue;
 108                 if (n + forward >= 0x3f && bmp[i] != -1) continue;
 109                 q = i<<5;
 110                 if (i > 0) {
 111                         unsigned k = bmp[i-1];
 112                         while (k & 0x80000000) {
 113                                 q--; k <<= 1;
 114                         }
 115                 }
 116                 if (n != 1) q = ((q-1)&~(n-1))+n;
 117                 while ((a = tstbits(bmp, q, n + forward))) {
 118                         q += a;
 119                         if (n != 1) q = ((q-1)&~(n-1))+n;
 120                         if (q>>5 > i) break;
 121                 }
 122                 if (!a) {
 123                         ret = bs + q;
 124                         goto rt;
 125                 }
 126         }
 127         rt:
 128         if (ret) {
 129                 if (s->s_hpfs_chk && ((ret >> 14) != (bs >> 14) || (bmp[(ret & 0x3fff) >> 5] | ~(((1 << n) - 1) << (ret & 0x1f))) != 0xffffffff)) {
 130                         hpfs_error(s, "Allocation doesn't work! Wanted %d, allocated at %08x", n, ret);
 131                         ret = 0;
 132                         goto b;
 133                 }
 134                 bmp[(ret & 0x3fff) >> 5] &= ~(((1 << n) - 1) << (ret & 0x1f));
 135                 hpfs_mark_4buffers_dirty(&qbh);
 136         }
 137         b:
 138         hpfs_brelse4(&qbh);
 139         uls:
 140         unlock_super(s);
 141         return ret;
 142 }
 143
 144 /*
 145  * Allocation strategy: 1) search place near the sector specified
 146  *                      2) search bitmap where free sectors last found
 147  *                      3) search all bitmaps
 148  *                      4) search all bitmaps ignoring number of pre-allocated
 149  *                              sectors
 150  */
 151
 152 secno hpfs_alloc_sector(struct super_block *s, secno near, unsigned n, int forward, int lock)
 153 {
 154         secno sec;
 155         unsigned i;
 156         unsigned n_bmps;
 157         int b = s->s_hpfs_c_bitmap;
 158         int f_p = 0;
 159         if (forward < 0) {
 160                 forward = -forward;
 161                 f_p = 1;
 162         }
 163         if (lock) hpfs_lock_creation(s);
 164         if (near && near < s->s_hpfs_fs_size)
 165                 if ((sec = alloc_in_bmp(s, near, n, f_p ? forward : forward/4))) goto ret;
 166         if (b != -1) {
 167                 if (b < 0x10000000) if ((sec = alloc_in_bmp(s, b<<14, n, f_p ? forward : forward/2))) goto ret;
 168                 else if ((sec = alloc_in_bmp(s, (b&0xfffffff)<<14, n, f_p ? forward : 0))) goto ret;
 169         }
 170         n_bmps = (s->s_hpfs_fs_size + 0x4000 - 1) >> 14;
 171         for (i = 0; i < n_bmps / 2; i++) {
 172                 if ((sec = alloc_in_bmp(s, (n_bmps/2+i) << 14, n, forward))) {
 173                         s->s_hpfs_c_bitmap = n_bmps/2+i;
 174                         goto ret;
 175                 }
 176                 if ((sec = alloc_in_bmp(s, (n_bmps/2-i-1) << 14, n, forward))) {
 177                         s->s_hpfs_c_bitmap = n_bmps/2-i-1;
 178                         goto ret;
 179                 }
 180         }
 181         if ((sec = alloc_in_bmp(s, (n_bmps-1) << 14, n, forward))) {
 182                 s->s_hpfs_c_bitmap = n_bmps-1;
 183                 goto ret;
 184         }
 185         if (!f_p) {
 186                 for (i = 0; i < n_bmps; i++)
 187                         if ((sec = alloc_in_bmp(s, i << 14, n, 0))) {
 188                                 s->s_hpfs_c_bitmap = 0x10000000 + i;
 189                                 goto ret;
 190                         }
 191         }
 192         sec = 0;
 193         ret:
 194         if (sec && f_p) {
 195                 for (i = 0; i < forward; i++) {
 196                         if (!hpfs_alloc_if_possible_nolock(s, sec + i + 1)) {
 197                                 hpfs_error(s, "Prealloc doesn't work! Wanted %d, allocated at %08x, can't allocate %d", forward, sec, i);
 198                                 sec = 0;
 199                                 break;
 200                         }
 201                 }
 202         }
 203         if (lock) hpfs_unlock_creation(s);
 204         return sec;
 205 }
 206
 207 static secno alloc_in_dirband(struct super_block *s, secno near, int lock)
 208 {
 209         unsigned nr = near;
 210         secno sec;
 211         if (nr < s->s_hpfs_dirband_start)
 212                 nr = s->s_hpfs_dirband_start;
 213         if (nr >= s->s_hpfs_dirband_start + s->s_hpfs_dirband_size)
 214                 nr = s->s_hpfs_dirband_start + s->s_hpfs_dirband_size - 4;
 215         nr -= s->s_hpfs_dirband_start;
 216         nr >>= 2;
 217         if (lock) hpfs_lock_creation(s);
 218         sec = alloc_in_bmp(s, (~0x3fff) | nr, 1, 0);
 219         if (lock) hpfs_unlock_creation(s);
 220         if (!sec) return 0;
 221         return ((sec & 0x3fff) << 2) + s->s_hpfs_dirband_start;
 222 }
 223
 224 /* Alloc sector if it's free */
 225
 226 int hpfs_alloc_if_possible_nolock(struct super_block *s, secno sec)
 227 {
 228         struct quad_buffer_head qbh;
 229         unsigned *bmp;
 230         lock_super(s);
 231         if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "aip"))) goto end;
 232         if (bmp[(sec & 0x3fff) >> 5] & (1 << (sec & 0x1f))) {
 233                 bmp[(sec & 0x3fff) >> 5] &= ~(1 << (sec & 0x1f));
 234                 hpfs_mark_4buffers_dirty(&qbh);
 235                 hpfs_brelse4(&qbh);
 236                 unlock_super(s);
 237                 return 1;
 238         }
 239         hpfs_brelse4(&qbh);
 240         end:
 241         unlock_super(s);
 242         return 0;
 243 }
 244
 245 int hpfs_alloc_if_possible(struct super_block *s, secno sec)
 246 {
 247         int r;
 248         hpfs_lock_creation(s);
 249         r = hpfs_alloc_if_possible_nolock(s, sec);
 250         hpfs_unlock_creation(s);
 251         return r;
 252 }
 253
 254 /* Free sectors in bitmaps */
 255
 256 void hpfs_free_sectors(struct super_block *s, secno sec, unsigned n)
 257 {
 258         struct quad_buffer_head qbh;
 259         unsigned *bmp;
 260         /*printk("2 - ");*/
 261         if (!n) return;
 262         if (sec < 0x12) {
 263                 hpfs_error(s, "Trying to free reserved sector %08x", sec);
 264                 return;
 265         }
 266         lock_super(s);
 267         new_map:
 268         if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "free"))) {
 269                 unlock_super(s);
 270                 return;
 271         }
 272         new_tst:
 273         if ((bmp[(sec & 0x3fff) >> 5] >> (sec & 0x1f) & 1)) {
 274                 hpfs_error(s, "sector %08x not allocated", sec);
 275                 hpfs_brelse4(&qbh);
 276                 unlock_super(s);
 277                 return;
 278         }
 279         bmp[(sec & 0x3fff) >> 5] |= 1 << (sec & 0x1f);
 280         if (!--n) {
 281                 hpfs_mark_4buffers_dirty(&qbh);
 282                 hpfs_brelse4(&qbh);
 283                 unlock_super(s);
 284                 return;
 285         }
 286         if (!(++sec & 0x3fff)) {
 287                 hpfs_mark_4buffers_dirty(&qbh);
 288                 hpfs_brelse4(&qbh);
 289                 goto new_map;
 290         }
 291         goto new_tst;
 292 }
 293
 294 /*
 295  * Check if there are at least n free dnodes on the filesystem.
 296  * Called before adding to dnode. If we run out of space while
 297  * splitting dnodes, it would corrupt dnode tree.
 298  */
 299
 300 int hpfs_check_free_dnodes(struct super_block *s, int n)
 301 {
 302         int n_bmps = (s->s_hpfs_fs_size + 0x4000 - 1) >> 14;
 303         int b = s->s_hpfs_c_bitmap & 0x0fffffff;
 304         int i, j;
 305         unsigned *bmp;
 306         struct quad_buffer_head qbh;
 307         if ((bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
 308                 for (j = 0; j < 512; j++) {
 309                         unsigned k;
 310                         if (!bmp[j]) continue;
 311                         for (k = bmp[j]; k; k >>= 1) if (k & 1) if (!--n) {
 312                                 hpfs_brelse4(&qbh);
 313                                 return 0;
 314                         }
 315                 }
 316         }
 317         hpfs_brelse4(&qbh);
 318         i = 0;
 319         if (s->s_hpfs_c_bitmap != -1 ) {
 320                 bmp = hpfs_map_bitmap(s, b, &qbh, "chkdn1");
 321                 goto chk_bmp;
 322         }
 323         chk_next:
 324         if (i == b) i++;
 325         if (i >= n_bmps) return 1;
 326         bmp = hpfs_map_bitmap(s, i, &qbh, "chkdn2");
 327         chk_bmp:
 328         if (bmp) {
 329                 for (j = 0; j < 512; j++) {
 330                         unsigned k;
 331                         if (!bmp[j]) continue;
 332                         for (k = 0xf; k; k <<= 4)
 333                                 if ((bmp[j] & k) == k) {
 334                                         if (!--n) {
 335                                                 hpfs_brelse4(&qbh);
 336                                                 return 0;
 337                                         }
 338                                 }
 339                 }
 340                 hpfs_brelse4(&qbh);
 341         }
 342         i++;
 343         goto chk_next;
 344 }
 345
 346 void hpfs_free_dnode(struct super_block *s, dnode_secno dno)
 347 {
 348         if (s->s_hpfs_chk) if (dno & 3) {
 349                 hpfs_error(s, "hpfs_free_dnode: dnode %08x not aligned", dno);
 350                 return;
 351         }
 352         if (dno < s->s_hpfs_dirband_start ||
 353             dno >= s->s_hpfs_dirband_start + s->s_hpfs_dirband_size) {
 354                 hpfs_free_sectors(s, dno, 4);
 355         } else {
 356                 struct quad_buffer_head qbh;
 357                 unsigned *bmp;
 358                 unsigned ssec = (dno - s->s_hpfs_dirband_start) / 4;
 359                 lock_super(s);
 360                 if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
 361                         unlock_super(s);
 362                         return;
 363                 }
 364                 bmp[ssec >> 5] |= 1 << (ssec & 0x1f);
 365                 hpfs_mark_4buffers_dirty(&qbh);
 366                 hpfs_brelse4(&qbh);
 367                 unlock_super(s);
 368         }
 369 }
 370
 371 struct dnode *hpfs_alloc_dnode(struct super_block *s, secno near,
 372                          dnode_secno *dno, struct quad_buffer_head *qbh,
 373                          int lock)
 374 {
 375         struct dnode *d;
 376         if (hpfs_count_one_bitmap(s, s->s_hpfs_dmap) > FREE_DNODES_ADD) {
 377                 if (!(*dno = alloc_in_dirband(s, near, lock)))
 378                         if (!(*dno = hpfs_alloc_sector(s, near, 4, 0, lock))) return NULL;
 379         } else {
 380                 if (!(*dno = hpfs_alloc_sector(s, near, 4, 0, lock)))
 381                         if (!(*dno = alloc_in_dirband(s, near, lock))) return NULL;
 382         }
 383         if (!(d = hpfs_get_4sectors(s, *dno, qbh))) {
 384                 hpfs_free_dnode(s, *dno);
 385                 return NULL;
 386         }
 387         memset(d, 0, 2048);
 388         d->magic = DNODE_MAGIC;
 389         d->first_free = 52;
 390         d->dirent[0] = 32;
 391         d->dirent[2] = 8;
 392         d->dirent[30] = 1;
 393         d->dirent[31] = 255;
 394         d->self = *dno;
 395         return d;
 396 }
 397
 398 struct fnode *hpfs_alloc_fnode(struct super_block *s, secno near, fnode_secno *fno,
 399                           struct buffer_head **bh)
 400 {
 401         struct fnode *f;
 402         if (!(*fno = hpfs_alloc_sector(s, near, 1, FNODE_ALLOC_FWD, 1))) return NULL;
 403         if (!(f = hpfs_get_sector(s, *fno, bh))) {
 404                 hpfs_free_sectors(s, *fno, 1);
 405                 return NULL;
 406         }
 407         memset(f, 0, 512);
 408         f->magic = FNODE_MAGIC;
 409         f->ea_offs = 0xc4;
 410         f->btree.n_free_nodes = 8;
 411         f->btree.first_free = 8;
 412         return f;
 413 }
 414
 415 struct anode *hpfs_alloc_anode(struct super_block *s, secno near, anode_secno *ano,
 416                           struct buffer_head **bh)
 417 {
 418         struct anode *a;
 419         if (!(*ano = hpfs_alloc_sector(s, near, 1, ANODE_ALLOC_FWD, 1))) return NULL;
 420         if (!(a = hpfs_get_sector(s, *ano, bh))) {
 421                 hpfs_free_sectors(s, *ano, 1);
 422                 return NULL;
 423         }
 424         memset(a, 0, 512);
 425         a->magic = ANODE_MAGIC;
 426         a->self = *ano;
 427         a->btree.n_free_nodes = 40;
 428         a->btree.n_used_nodes = 0;
 429         a->btree.first_free = 8;
 430         return a;
 431 }