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 static void hpfs_claim_alloc(struct super_block *s, secno sec)
  12 {
  13         struct hpfs_sb_info *sbi = hpfs_sb(s);
  14         if (sbi->sb_n_free != (unsigned)-1) {
  15                 if (unlikely(!sbi->sb_n_free)) {
  16                         hpfs_error(s, "free count underflow, allocating sector %08x", sec);
  17                         sbi->sb_n_free = -1;
  18                         return;
  19                 }
  20                 sbi->sb_n_free--;
  21         }
  22 }
  23
  24 static void hpfs_claim_free(struct super_block *s, secno sec)
  25 {
  26         struct hpfs_sb_info *sbi = hpfs_sb(s);
  27         if (sbi->sb_n_free != (unsigned)-1) {
  28                 if (unlikely(sbi->sb_n_free >= sbi->sb_fs_size)) {
  29                         hpfs_error(s, "free count overflow, freeing sector %08x", sec);
  30                         sbi->sb_n_free = -1;
  31                         return;
  32                 }
  33                 sbi->sb_n_free++;
  34         }
  35 }
  36
  37 static void hpfs_claim_dirband_alloc(struct super_block *s, secno sec)
  38 {
  39         struct hpfs_sb_info *sbi = hpfs_sb(s);
  40         if (sbi->sb_n_free_dnodes != (unsigned)-1) {
  41                 if (unlikely(!sbi->sb_n_free_dnodes)) {
  42                         hpfs_error(s, "dirband free count underflow, allocating sector %08x", sec);
  43                         sbi->sb_n_free_dnodes = -1;
  44                         return;
  45                 }
  46                 sbi->sb_n_free_dnodes--;
  47         }
  48 }
  49
  50 static void hpfs_claim_dirband_free(struct super_block *s, secno sec)
  51 {
  52         struct hpfs_sb_info *sbi = hpfs_sb(s);
  53         if (sbi->sb_n_free_dnodes != (unsigned)-1) {
  54                 if (unlikely(sbi->sb_n_free_dnodes >= sbi->sb_dirband_size / 4)) {
  55                         hpfs_error(s, "dirband free count overflow, freeing sector %08x", sec);
  56                         sbi->sb_n_free_dnodes = -1;
  57                         return;
  58                 }
  59                 sbi->sb_n_free_dnodes++;
  60         }
  61 }
  62
  63 /*
  64  * Check if a sector is allocated in bitmap
  65  * This is really slow. Turned on only if chk==2
  66  */
  67
  68 static int chk_if_allocated(struct super_block *s, secno sec, char *msg)
  69 {
  70         struct quad_buffer_head qbh;
  71         __le32 *bmp;
  72         if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "chk"))) goto fail;
  73         if ((le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) >> (sec & 0x1f)) & 1) {
  74                 hpfs_error(s, "sector '%s' - %08x not allocated in bitmap", msg, sec);
  75                 goto fail1;
  76         }
  77         hpfs_brelse4(&qbh);
  78         if (sec >= hpfs_sb(s)->sb_dirband_start && sec < hpfs_sb(s)->sb_dirband_start + hpfs_sb(s)->sb_dirband_size) {
  79                 unsigned ssec = (sec - hpfs_sb(s)->sb_dirband_start) / 4;
  80                 if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto fail;
  81                 if ((le32_to_cpu(bmp[ssec >> 5]) >> (ssec & 0x1f)) & 1) {
  82                         hpfs_error(s, "sector '%s' - %08x not allocated in directory bitmap", msg, sec);
  83                         goto fail1;
  84                 }
  85                 hpfs_brelse4(&qbh);
  86         }
  87         return 0;
  88         fail1:
  89         hpfs_brelse4(&qbh);
  90         fail:
  91         return 1;
  92 }
  93
  94 /*
  95  * Check if sector(s) have proper number and additionally check if they're
  96  * allocated in bitmap.
  97  */
  98
  99 int hpfs_chk_sectors(struct super_block *s, secno start, int len, char *msg)
 100 {
 101         if (start + len < start || start < 0x12 ||
 102             start + len > hpfs_sb(s)->sb_fs_size) {
 103                 hpfs_error(s, "sector(s) '%s' badly placed at %08x", msg, start);
 104                 return 1;
 105         }
 106         if (hpfs_sb(s)->sb_chk>=2) {
 107                 int i;
 108                 for (i = 0; i < len; i++)
 109                         if (chk_if_allocated(s, start + i, msg)) return 1;
 110         }
 111         return 0;
 112 }
 113
 114 static secno alloc_in_bmp(struct super_block *s, secno near, unsigned n, unsigned forward)
 115 {
 116         struct quad_buffer_head qbh;
 117         __le32 *bmp;
 118         unsigned bs = near & ~0x3fff;
 119         unsigned nr = (near & 0x3fff) & ~(n - 1);
 120         /*unsigned mnr;*/
 121         unsigned i, q;
 122         int a, b;
 123         secno ret = 0;
 124         if (n != 1 && n != 4) {
 125                 hpfs_error(s, "Bad allocation size: %d", n);
 126                 return 0;
 127         }
 128         if (bs != ~0x3fff) {
 129                 if (!(bmp = hpfs_map_bitmap(s, near >> 14, &qbh, "aib"))) goto uls;
 130         } else {
 131                 if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto uls;
 132         }
 133         if (!tstbits(bmp, nr, n + forward)) {
 134                 ret = bs + nr;
 135                 goto rt;
 136         }
 137         q = nr + n; b = 0;
 138         while ((a = tstbits(bmp, q, n + forward)) != 0) {
 139                 q += a;
 140                 if (n != 1) q = ((q-1)&~(n-1))+n;
 141                 if (!b) {
 142                         if (q>>5 != nr>>5) {
 143                                 b = 1;
 144                                 q = nr & 0x1f;
 145                         }
 146                 } else if (q > nr) break;
 147         }
 148         if (!a) {
 149                 ret = bs + q;
 150                 goto rt;
 151         }
 152         nr >>= 5;
 153         /*for (i = nr + 1; i != nr; i++, i &= 0x1ff) */
 154         i = nr;
 155         do {
 156                 if (!le32_to_cpu(bmp[i])) goto cont;
 157                 if (n + forward >= 0x3f && le32_to_cpu(bmp[i]) != 0xffffffff) goto cont;
 158                 q = i<<5;
 159                 if (i > 0) {
 160                         unsigned k = le32_to_cpu(bmp[i-1]);
 161                         while (k & 0x80000000) {
 162                                 q--; k <<= 1;
 163                         }
 164                 }
 165                 if (n != 1) q = ((q-1)&~(n-1))+n;
 166                 while ((a = tstbits(bmp, q, n + forward)) != 0) {
 167                         q += a;
 168                         if (n != 1) q = ((q-1)&~(n-1))+n;
 169                         if (q>>5 > i) break;
 170                 }
 171                 if (!a) {
 172                         ret = bs + q;
 173                         goto rt;
 174                 }
 175                 cont:
 176                 i++, i &= 0x1ff;
 177         } while (i != nr);
 178         rt:
 179         if (ret) {
 180                 if (hpfs_sb(s)->sb_chk && ((ret >> 14) != (bs >> 14) || (le32_to_cpu(bmp[(ret & 0x3fff) >> 5]) | ~(((1 << n) - 1) << (ret & 0x1f))) != 0xffffffff)) {
 181                         hpfs_error(s, "Allocation doesn't work! Wanted %d, allocated at %08x", n, ret);
 182                         ret = 0;
 183                         goto b;
 184                 }
 185                 bmp[(ret & 0x3fff) >> 5] &= cpu_to_le32(~(((1 << n) - 1) << (ret & 0x1f)));
 186                 hpfs_mark_4buffers_dirty(&qbh);
 187         }
 188         b:
 189         hpfs_brelse4(&qbh);
 190         uls:
 191         return ret;
 192 }
 193
 194 /*
 195  * Allocation strategy: 1) search place near the sector specified
 196  *                      2) search bitmap where free sectors last found
 197  *                      3) search all bitmaps
 198  *                      4) search all bitmaps ignoring number of pre-allocated
 199  *                              sectors
 200  */
 201
 202 secno hpfs_alloc_sector(struct super_block *s, secno near, unsigned n, int forward)
 203 {
 204         secno sec;
 205         int i;
 206         unsigned n_bmps;
 207         struct hpfs_sb_info *sbi = hpfs_sb(s);
 208         int f_p = 0;
 209         int near_bmp;
 210         if (forward < 0) {
 211                 forward = -forward;
 212                 f_p = 1;
 213         }
 214         n_bmps = (sbi->sb_fs_size + 0x4000 - 1) >> 14;
 215         if (near && near < sbi->sb_fs_size) {
 216                 if ((sec = alloc_in_bmp(s, near, n, f_p ? forward : forward/4))) goto ret;
 217                 near_bmp = near >> 14;
 218         } else near_bmp = n_bmps / 2;
 219         /*
 220         if (b != -1) {
 221                 if ((sec = alloc_in_bmp(s, b<<14, n, f_p ? forward : forward/2))) {
 222                         b &= 0x0fffffff;
 223                         goto ret;
 224                 }
 225                 if (b > 0x10000000) if ((sec = alloc_in_bmp(s, (b&0xfffffff)<<14, n, f_p ? forward : 0))) goto ret;
 226         */
 227         if (!f_p) if (forward > sbi->sb_max_fwd_alloc) forward = sbi->sb_max_fwd_alloc;
 228         less_fwd:
 229         for (i = 0; i < n_bmps; i++) {
 230                 if (near_bmp+i < n_bmps && ((sec = alloc_in_bmp(s, (near_bmp+i) << 14, n, forward)))) {
 231                         sbi->sb_c_bitmap = near_bmp+i;
 232                         goto ret;
 233                 }
 234                 if (!forward) {
 235                         if (near_bmp-i-1 >= 0 && ((sec = alloc_in_bmp(s, (near_bmp-i-1) << 14, n, forward)))) {
 236                                 sbi->sb_c_bitmap = near_bmp-i-1;
 237                                 goto ret;
 238                         }
 239                 } else {
 240                         if (near_bmp+i >= n_bmps && ((sec = alloc_in_bmp(s, (near_bmp+i-n_bmps) << 14, n, forward)))) {
 241                                 sbi->sb_c_bitmap = near_bmp+i-n_bmps;
 242                                 goto ret;
 243                         }
 244                 }
 245                 if (i == 1 && sbi->sb_c_bitmap != -1 && ((sec = alloc_in_bmp(s, (sbi->sb_c_bitmap) << 14, n, forward)))) {
 246                         goto ret;
 247                 }
 248         }
 249         if (!f_p) {
 250                 if (forward) {
 251                         sbi->sb_max_fwd_alloc = forward * 3 / 4;
 252                         forward /= 2;
 253                         goto less_fwd;
 254                 }
 255         }
 256         sec = 0;
 257         ret:
 258         if (sec) {
 259                 i = 0;
 260                 do
 261                         hpfs_claim_alloc(s, sec + i);
 262                 while (unlikely(++i < n));
 263         }
 264         if (sec && f_p) {
 265                 for (i = 0; i < forward; i++) {
 266                         if (!hpfs_alloc_if_possible(s, sec + n + i)) {
 267                                 hpfs_error(s, "Prealloc doesn't work! Wanted %d, allocated at %08x, can't allocate %d", forward, sec, i);
 268                                 sec = 0;
 269                                 break;
 270                         }
 271                 }
 272         }
 273         return sec;
 274 }
 275
 276 static secno alloc_in_dirband(struct super_block *s, secno near)
 277 {
 278         unsigned nr = near;
 279         secno sec;
 280         struct hpfs_sb_info *sbi = hpfs_sb(s);
 281         if (nr < sbi->sb_dirband_start)
 282                 nr = sbi->sb_dirband_start;
 283         if (nr >= sbi->sb_dirband_start + sbi->sb_dirband_size)
 284                 nr = sbi->sb_dirband_start + sbi->sb_dirband_size - 4;
 285         nr -= sbi->sb_dirband_start;
 286         nr >>= 2;
 287         sec = alloc_in_bmp(s, (~0x3fff) | nr, 1, 0);
 288         if (!sec) return 0;
 289         hpfs_claim_dirband_alloc(s, sec);
 290         return ((sec & 0x3fff) << 2) + sbi->sb_dirband_start;
 291 }
 292
 293 /* Alloc sector if it's free */
 294
 295 int hpfs_alloc_if_possible(struct super_block *s, secno sec)
 296 {
 297         struct quad_buffer_head qbh;
 298         __le32 *bmp;
 299         if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "aip"))) goto end;
 300         if (le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) & (1 << (sec & 0x1f))) {
 301                 bmp[(sec & 0x3fff) >> 5] &= cpu_to_le32(~(1 << (sec & 0x1f)));
 302                 hpfs_mark_4buffers_dirty(&qbh);
 303                 hpfs_brelse4(&qbh);
 304                 hpfs_claim_alloc(s, sec);
 305                 return 1;
 306         }
 307         hpfs_brelse4(&qbh);
 308         end:
 309         return 0;
 310 }
 311
 312 /* Free sectors in bitmaps */
 313
 314 void hpfs_free_sectors(struct super_block *s, secno sec, unsigned n)
 315 {
 316         struct quad_buffer_head qbh;
 317         __le32 *bmp;
 318         struct hpfs_sb_info *sbi = hpfs_sb(s);
 319         /*printk("2 - ");*/
 320         if (!n) return;
 321         if (sec < 0x12) {
 322                 hpfs_error(s, "Trying to free reserved sector %08x", sec);
 323                 return;
 324         }
 325         sbi->sb_max_fwd_alloc += n > 0xffff ? 0xffff : n;
 326         if (sbi->sb_max_fwd_alloc > 0xffffff) sbi->sb_max_fwd_alloc = 0xffffff;
 327         new_map:
 328         if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "free"))) {
 329                 return;
 330         }
 331         new_tst:
 332         if ((le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) >> (sec & 0x1f) & 1)) {
 333                 hpfs_error(s, "sector %08x not allocated", sec);
 334                 hpfs_brelse4(&qbh);
 335                 return;
 336         }
 337         bmp[(sec & 0x3fff) >> 5] |= cpu_to_le32(1 << (sec & 0x1f));
 338         hpfs_claim_free(s, sec);
 339         if (!--n) {
 340                 hpfs_mark_4buffers_dirty(&qbh);
 341                 hpfs_brelse4(&qbh);
 342                 return;
 343         }
 344         if (!(++sec & 0x3fff)) {
 345                 hpfs_mark_4buffers_dirty(&qbh);
 346                 hpfs_brelse4(&qbh);
 347                 goto new_map;
 348         }
 349         goto new_tst;
 350 }
 351
 352 /*
 353  * Check if there are at least n free dnodes on the filesystem.
 354  * Called before adding to dnode. If we run out of space while
 355  * splitting dnodes, it would corrupt dnode tree.
 356  */
 357
 358 int hpfs_check_free_dnodes(struct super_block *s, int n)
 359 {
 360         int n_bmps = (hpfs_sb(s)->sb_fs_size + 0x4000 - 1) >> 14;
 361         int b = hpfs_sb(s)->sb_c_bitmap & 0x0fffffff;
 362         int i, j;
 363         __le32 *bmp;
 364         struct quad_buffer_head qbh;
 365         if ((bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
 366                 for (j = 0; j < 512; j++) {
 367                         unsigned k;
 368                         if (!le32_to_cpu(bmp[j])) continue;
 369                         for (k = le32_to_cpu(bmp[j]); k; k >>= 1) if (k & 1) if (!--n) {
 370                                 hpfs_brelse4(&qbh);
 371                                 return 0;
 372                         }
 373                 }
 374         }
 375         hpfs_brelse4(&qbh);
 376         i = 0;
 377         if (hpfs_sb(s)->sb_c_bitmap != -1) {
 378                 bmp = hpfs_map_bitmap(s, b, &qbh, "chkdn1");
 379                 goto chk_bmp;
 380         }
 381         chk_next:
 382         if (i == b) i++;
 383         if (i >= n_bmps) return 1;
 384         bmp = hpfs_map_bitmap(s, i, &qbh, "chkdn2");
 385         chk_bmp:
 386         if (bmp) {
 387                 for (j = 0; j < 512; j++) {
 388                         u32 k;
 389                         if (!le32_to_cpu(bmp[j])) continue;
 390                         for (k = 0xf; k; k <<= 4)
 391                                 if ((le32_to_cpu(bmp[j]) & k) == k) {
 392                                         if (!--n) {
 393                                                 hpfs_brelse4(&qbh);
 394                                                 return 0;
 395                                         }
 396                                 }
 397                 }
 398                 hpfs_brelse4(&qbh);
 399         }
 400         i++;
 401         goto chk_next;
 402 }
 403
 404 void hpfs_free_dnode(struct super_block *s, dnode_secno dno)
 405 {
 406         if (hpfs_sb(s)->sb_chk) if (dno & 3) {
 407                 hpfs_error(s, "hpfs_free_dnode: dnode %08x not aligned", dno);
 408                 return;
 409         }
 410         if (dno < hpfs_sb(s)->sb_dirband_start ||
 411             dno >= hpfs_sb(s)->sb_dirband_start + hpfs_sb(s)->sb_dirband_size) {
 412                 hpfs_free_sectors(s, dno, 4);
 413         } else {
 414                 struct quad_buffer_head qbh;
 415                 __le32 *bmp;
 416                 unsigned ssec = (dno - hpfs_sb(s)->sb_dirband_start) / 4;
 417                 if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
 418                         return;
 419                 }
 420                 bmp[ssec >> 5] |= cpu_to_le32(1 << (ssec & 0x1f));
 421                 hpfs_mark_4buffers_dirty(&qbh);
 422                 hpfs_brelse4(&qbh);
 423                 hpfs_claim_dirband_free(s, dno);
 424         }
 425 }
 426
 427 struct dnode *hpfs_alloc_dnode(struct super_block *s, secno near,
 428                          dnode_secno *dno, struct quad_buffer_head *qbh)
 429 {
 430         struct dnode *d;
 431         if (hpfs_get_free_dnodes(s) > FREE_DNODES_ADD) {
 432                 if (!(*dno = alloc_in_dirband(s, near)))
 433                         if (!(*dno = hpfs_alloc_sector(s, near, 4, 0))) return NULL;
 434         } else {
 435                 if (!(*dno = hpfs_alloc_sector(s, near, 4, 0)))
 436                         if (!(*dno = alloc_in_dirband(s, near))) return NULL;
 437         }
 438         if (!(d = hpfs_get_4sectors(s, *dno, qbh))) {
 439                 hpfs_free_dnode(s, *dno);
 440                 return NULL;
 441         }
 442         memset(d, 0, 2048);
 443         d->magic = cpu_to_le32(DNODE_MAGIC);
 444         d->first_free = cpu_to_le32(52);
 445         d->dirent[0] = 32;
 446         d->dirent[2] = 8;
 447         d->dirent[30] = 1;
 448         d->dirent[31] = 255;
 449         d->self = cpu_to_le32(*dno);
 450         return d;
 451 }
 452
 453 struct fnode *hpfs_alloc_fnode(struct super_block *s, secno near, fnode_secno *fno,
 454                           struct buffer_head **bh)
 455 {
 456         struct fnode *f;
 457         if (!(*fno = hpfs_alloc_sector(s, near, 1, FNODE_ALLOC_FWD))) return NULL;
 458         if (!(f = hpfs_get_sector(s, *fno, bh))) {
 459                 hpfs_free_sectors(s, *fno, 1);
 460                 return NULL;
 461         }
 462         memset(f, 0, 512);
 463         f->magic = cpu_to_le32(FNODE_MAGIC);
 464         f->ea_offs = cpu_to_le16(0xc4);
 465         f->btree.n_free_nodes = 8;
 466         f->btree.first_free = cpu_to_le16(8);
 467         return f;
 468 }
 469
 470 struct anode *hpfs_alloc_anode(struct super_block *s, secno near, anode_secno *ano,
 471                           struct buffer_head **bh)
 472 {
 473         struct anode *a;
 474         if (!(*ano = hpfs_alloc_sector(s, near, 1, ANODE_ALLOC_FWD))) return NULL;
 475         if (!(a = hpfs_get_sector(s, *ano, bh))) {
 476                 hpfs_free_sectors(s, *ano, 1);
 477                 return NULL;
 478         }
 479         memset(a, 0, 512);
 480         a->magic = cpu_to_le32(ANODE_MAGIC);
 481         a->self = cpu_to_le32(*ano);
 482         a->btree.n_free_nodes = 40;
 483         a->btree.n_used_nodes = 0;
 484         a->btree.first_free = cpu_to_le16(8);
 485         return a;
 486 }