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