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         __le32 *bmp;
  20         if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "chk"))) goto fail;
  21         if ((le32_to_cpu(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 ((le32_to_cpu(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         __le32 *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         if (bs != ~0x3fff) {
  77                 if (!(bmp = hpfs_map_bitmap(s, near >> 14, &qbh, "aib"))) goto uls;
  78         } else {
  79                 if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto uls;
  80         }
  81         if (!tstbits(bmp, nr, n + forward)) {
  82                 ret = bs + nr;
  83                 goto rt;
  84         }
  85         q = nr + n; b = 0;
  86         while ((a = tstbits(bmp, q, n + forward)) != 0) {
  87                 q += a;
  88                 if (n != 1) q = ((q-1)&~(n-1))+n;
  89                 if (!b) {
  90                         if (q>>5 != nr>>5) {
  91                                 b = 1;
  92                                 q = nr & 0x1f;
  93                         }
  94                 } else if (q > nr) break;
  95         }
  96         if (!a) {
  97                 ret = bs + q;
  98                 goto rt;
  99         }
 100         nr >>= 5;
 101         /*for (i = nr + 1; i != nr; i++, i &= 0x1ff) */
 102         i = nr;
 103         do {
 104                 if (!le32_to_cpu(bmp[i])) goto cont;
 105                 if (n + forward >= 0x3f && le32_to_cpu(bmp[i]) != 0xffffffff) goto cont;
 106                 q = i<<5;
 107                 if (i > 0) {
 108                         unsigned k = le32_to_cpu(bmp[i-1]);
 109                         while (k & 0x80000000) {
 110                                 q--; k <<= 1;
 111                         }
 112                 }
 113                 if (n != 1) q = ((q-1)&~(n-1))+n;
 114                 while ((a = tstbits(bmp, q, n + forward)) != 0) {
 115                         q += a;
 116                         if (n != 1) q = ((q-1)&~(n-1))+n;
 117                         if (q>>5 > i) break;
 118                 }
 119                 if (!a) {
 120                         ret = bs + q;
 121                         goto rt;
 122                 }
 123                 cont:
 124                 i++, i &= 0x1ff;
 125         } while (i != nr);
 126         rt:
 127         if (ret) {
 128                 if (hpfs_sb(s)->sb_chk && ((ret >> 14) != (bs >> 14) || (le32_to_cpu(bmp[(ret & 0x3fff) >> 5]) | ~(((1 << n) - 1) << (ret & 0x1f))) != 0xffffffff)) {
 129                         hpfs_error(s, "Allocation doesn't work! Wanted %d, allocated at %08x", n, ret);
 130                         ret = 0;
 131                         goto b;
 132                 }
 133                 bmp[(ret & 0x3fff) >> 5] &= cpu_to_le32(~(((1 << n) - 1) << (ret & 0x1f)));
 134                 hpfs_mark_4buffers_dirty(&qbh);
 135         }
 136         b:
 137         hpfs_brelse4(&qbh);
 138         uls:
 139         return ret;
 140 }
 141
 142 /*
 143  * Allocation strategy: 1) search place near the sector specified
 144  *                      2) search bitmap where free sectors last found
 145  *                      3) search all bitmaps
 146  *                      4) search all bitmaps ignoring number of pre-allocated
 147  *                              sectors
 148  */
 149
 150 secno hpfs_alloc_sector(struct super_block *s, secno near, unsigned n, int forward)
 151 {
 152         secno sec;
 153         int i;
 154         unsigned n_bmps;
 155         struct hpfs_sb_info *sbi = hpfs_sb(s);
 156         int f_p = 0;
 157         int near_bmp;
 158         if (forward < 0) {
 159                 forward = -forward;
 160                 f_p = 1;
 161         }
 162         n_bmps = (sbi->sb_fs_size + 0x4000 - 1) >> 14;
 163         if (near && near < sbi->sb_fs_size) {
 164                 if ((sec = alloc_in_bmp(s, near, n, f_p ? forward : forward/4))) goto ret;
 165                 near_bmp = near >> 14;
 166         } else near_bmp = n_bmps / 2;
 167         /*
 168         if (b != -1) {
 169                 if ((sec = alloc_in_bmp(s, b<<14, n, f_p ? forward : forward/2))) {
 170                         b &= 0x0fffffff;
 171                         goto ret;
 172                 }
 173                 if (b > 0x10000000) if ((sec = alloc_in_bmp(s, (b&0xfffffff)<<14, n, f_p ? forward : 0))) goto ret;
 174         */
 175         if (!f_p) if (forward > sbi->sb_max_fwd_alloc) forward = sbi->sb_max_fwd_alloc;
 176         less_fwd:
 177         for (i = 0; i < n_bmps; i++) {
 178                 if (near_bmp+i < n_bmps && ((sec = alloc_in_bmp(s, (near_bmp+i) << 14, n, forward)))) {
 179                         sbi->sb_c_bitmap = near_bmp+i;
 180                         goto ret;
 181                 }
 182                 if (!forward) {
 183                         if (near_bmp-i-1 >= 0 && ((sec = alloc_in_bmp(s, (near_bmp-i-1) << 14, n, forward)))) {
 184                                 sbi->sb_c_bitmap = near_bmp-i-1;
 185                                 goto ret;
 186                         }
 187                 } else {
 188                         if (near_bmp+i >= n_bmps && ((sec = alloc_in_bmp(s, (near_bmp+i-n_bmps) << 14, n, forward)))) {
 189                                 sbi->sb_c_bitmap = near_bmp+i-n_bmps;
 190                                 goto ret;
 191                         }
 192                 }
 193                 if (i == 1 && sbi->sb_c_bitmap != -1 && ((sec = alloc_in_bmp(s, (sbi->sb_c_bitmap) << 14, n, forward)))) {
 194                         goto ret;
 195                 }
 196         }
 197         if (!f_p) {
 198                 if (forward) {
 199                         sbi->sb_max_fwd_alloc = forward * 3 / 4;
 200                         forward /= 2;
 201                         goto less_fwd;
 202                 }
 203         }
 204         sec = 0;
 205         ret:
 206         if (sec && f_p) {
 207                 for (i = 0; i < forward; i++) {
 208                         if (!hpfs_alloc_if_possible(s, sec + i + 1)) {
 209                                 hpfs_error(s, "Prealloc doesn't work! Wanted %d, allocated at %08x, can't allocate %d", forward, sec, i);
 210                                 sec = 0;
 211                                 break;
 212                         }
 213                 }
 214         }
 215         return sec;
 216 }
 217
 218 static secno alloc_in_dirband(struct super_block *s, secno near)
 219 {
 220         unsigned nr = near;
 221         secno sec;
 222         struct hpfs_sb_info *sbi = hpfs_sb(s);
 223         if (nr < sbi->sb_dirband_start)
 224                 nr = sbi->sb_dirband_start;
 225         if (nr >= sbi->sb_dirband_start + sbi->sb_dirband_size)
 226                 nr = sbi->sb_dirband_start + sbi->sb_dirband_size - 4;
 227         nr -= sbi->sb_dirband_start;
 228         nr >>= 2;
 229         sec = alloc_in_bmp(s, (~0x3fff) | nr, 1, 0);
 230         if (!sec) return 0;
 231         return ((sec & 0x3fff) << 2) + sbi->sb_dirband_start;
 232 }
 233
 234 /* Alloc sector if it's free */
 235
 236 int hpfs_alloc_if_possible(struct super_block *s, secno sec)
 237 {
 238         struct quad_buffer_head qbh;
 239         __le32 *bmp;
 240         if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "aip"))) goto end;
 241         if (le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) & (1 << (sec & 0x1f))) {
 242                 bmp[(sec & 0x3fff) >> 5] &= cpu_to_le32(~(1 << (sec & 0x1f)));
 243                 hpfs_mark_4buffers_dirty(&qbh);
 244                 hpfs_brelse4(&qbh);
 245                 return 1;
 246         }
 247         hpfs_brelse4(&qbh);
 248         end:
 249         return 0;
 250 }
 251
 252 /* Free sectors in bitmaps */
 253
 254 void hpfs_free_sectors(struct super_block *s, secno sec, unsigned n)
 255 {
 256         struct quad_buffer_head qbh;
 257         __le32 *bmp;
 258         struct hpfs_sb_info *sbi = hpfs_sb(s);
 259         /*printk("2 - ");*/
 260         if (!n) return;
 261         if (sec < 0x12) {
 262                 hpfs_error(s, "Trying to free reserved sector %08x", sec);
 263                 return;
 264         }
 265         sbi->sb_max_fwd_alloc += n > 0xffff ? 0xffff : n;
 266         if (sbi->sb_max_fwd_alloc > 0xffffff) sbi->sb_max_fwd_alloc = 0xffffff;
 267         new_map:
 268         if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "free"))) {
 269                 return;
 270         }
 271         new_tst:
 272         if ((le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) >> (sec & 0x1f) & 1)) {
 273                 hpfs_error(s, "sector %08x not allocated", sec);
 274                 hpfs_brelse4(&qbh);
 275                 return;
 276         }
 277         bmp[(sec & 0x3fff) >> 5] |= cpu_to_le32(1 << (sec & 0x1f));
 278         if (!--n) {
 279                 hpfs_mark_4buffers_dirty(&qbh);
 280                 hpfs_brelse4(&qbh);
 281                 return;
 282         }
 283         if (!(++sec & 0x3fff)) {
 284                 hpfs_mark_4buffers_dirty(&qbh);
 285                 hpfs_brelse4(&qbh);
 286                 goto new_map;
 287         }
 288         goto new_tst;
 289 }
 290
 291 /*
 292  * Check if there are at least n free dnodes on the filesystem.
 293  * Called before adding to dnode. If we run out of space while
 294  * splitting dnodes, it would corrupt dnode tree.
 295  */
 296
 297 int hpfs_check_free_dnodes(struct super_block *s, int n)
 298 {
 299         int n_bmps = (hpfs_sb(s)->sb_fs_size + 0x4000 - 1) >> 14;
 300         int b = hpfs_sb(s)->sb_c_bitmap & 0x0fffffff;
 301         int i, j;
 302         __le32 *bmp;
 303         struct quad_buffer_head qbh;
 304         if ((bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
 305                 for (j = 0; j < 512; j++) {
 306                         unsigned k;
 307                         if (!le32_to_cpu(bmp[j])) continue;
 308                         for (k = le32_to_cpu(bmp[j]); k; k >>= 1) if (k & 1) if (!--n) {
 309                                 hpfs_brelse4(&qbh);
 310                                 return 0;
 311                         }
 312                 }
 313         }
 314         hpfs_brelse4(&qbh);
 315         i = 0;
 316         if (hpfs_sb(s)->sb_c_bitmap != -1) {
 317                 bmp = hpfs_map_bitmap(s, b, &qbh, "chkdn1");
 318                 goto chk_bmp;
 319         }
 320         chk_next:
 321         if (i == b) i++;
 322         if (i >= n_bmps) return 1;
 323         bmp = hpfs_map_bitmap(s, i, &qbh, "chkdn2");
 324         chk_bmp:
 325         if (bmp) {
 326                 for (j = 0; j < 512; j++) {
 327                         u32 k;
 328                         if (!le32_to_cpu(bmp[j])) continue;
 329                         for (k = 0xf; k; k <<= 4)
 330                                 if ((le32_to_cpu(bmp[j]) & k) == k) {
 331                                         if (!--n) {
 332                                                 hpfs_brelse4(&qbh);
 333                                                 return 0;
 334                                         }
 335                                 }
 336                 }
 337                 hpfs_brelse4(&qbh);
 338         }
 339         i++;
 340         goto chk_next;
 341 }
 342
 343 void hpfs_free_dnode(struct super_block *s, dnode_secno dno)
 344 {
 345         if (hpfs_sb(s)->sb_chk) if (dno & 3) {
 346                 hpfs_error(s, "hpfs_free_dnode: dnode %08x not aligned", dno);
 347                 return;
 348         }
 349         if (dno < hpfs_sb(s)->sb_dirband_start ||
 350             dno >= hpfs_sb(s)->sb_dirband_start + hpfs_sb(s)->sb_dirband_size) {
 351                 hpfs_free_sectors(s, dno, 4);
 352         } else {
 353                 struct quad_buffer_head qbh;
 354                 __le32 *bmp;
 355                 unsigned ssec = (dno - hpfs_sb(s)->sb_dirband_start) / 4;
 356                 if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
 357                         return;
 358                 }
 359                 bmp[ssec >> 5] |= cpu_to_le32(1 << (ssec & 0x1f));
 360                 hpfs_mark_4buffers_dirty(&qbh);
 361                 hpfs_brelse4(&qbh);
 362         }
 363 }
 364
 365 struct dnode *hpfs_alloc_dnode(struct super_block *s, secno near,
 366                          dnode_secno *dno, struct quad_buffer_head *qbh)
 367 {
 368         struct dnode *d;
 369         if (hpfs_count_one_bitmap(s, hpfs_sb(s)->sb_dmap) > FREE_DNODES_ADD) {
 370                 if (!(*dno = alloc_in_dirband(s, near)))
 371                         if (!(*dno = hpfs_alloc_sector(s, near, 4, 0))) return NULL;
 372         } else {
 373                 if (!(*dno = hpfs_alloc_sector(s, near, 4, 0)))
 374                         if (!(*dno = alloc_in_dirband(s, near))) return NULL;
 375         }
 376         if (!(d = hpfs_get_4sectors(s, *dno, qbh))) {
 377                 hpfs_free_dnode(s, *dno);
 378                 return NULL;
 379         }
 380         memset(d, 0, 2048);
 381         d->magic = cpu_to_le32(DNODE_MAGIC);
 382         d->first_free = cpu_to_le32(52);
 383         d->dirent[0] = 32;
 384         d->dirent[2] = 8;
 385         d->dirent[30] = 1;
 386         d->dirent[31] = 255;
 387         d->self = cpu_to_le32(*dno);
 388         return d;
 389 }
 390
 391 struct fnode *hpfs_alloc_fnode(struct super_block *s, secno near, fnode_secno *fno,
 392                           struct buffer_head **bh)
 393 {
 394         struct fnode *f;
 395         if (!(*fno = hpfs_alloc_sector(s, near, 1, FNODE_ALLOC_FWD))) return NULL;
 396         if (!(f = hpfs_get_sector(s, *fno, bh))) {
 397                 hpfs_free_sectors(s, *fno, 1);
 398                 return NULL;
 399         }
 400         memset(f, 0, 512);
 401         f->magic = cpu_to_le32(FNODE_MAGIC);
 402         f->ea_offs = cpu_to_le16(0xc4);
 403         f->btree.n_free_nodes = 8;
 404         f->btree.first_free = cpu_to_le16(8);
 405         return f;
 406 }
 407
 408 struct anode *hpfs_alloc_anode(struct super_block *s, secno near, anode_secno *ano,
 409                           struct buffer_head **bh)
 410 {
 411         struct anode *a;
 412         if (!(*ano = hpfs_alloc_sector(s, near, 1, ANODE_ALLOC_FWD))) return NULL;
 413         if (!(a = hpfs_get_sector(s, *ano, bh))) {
 414                 hpfs_free_sectors(s, *ano, 1);
 415                 return NULL;
 416         }
 417         memset(a, 0, 512);
 418         a->magic = cpu_to_le32(ANODE_MAGIC);
 419         a->self = cpu_to_le32(*ano);
 420         a->btree.n_free_nodes = 40;
 421         a->btree.n_used_nodes = 0;
 422         a->btree.first_free = cpu_to_le16(8);
 423         return a;
 424 }