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