git.oblomov.eu Git - linux-2.6/blob - fs/reiserfs/bitmap.c

   1 /*
   2  * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
   3  */
   4 /* Reiserfs block (de)allocator, bitmap-based. */
   5
   6 #include <linux/config.h>
   7 #include <linux/time.h>
   8 #include <linux/reiserfs_fs.h>
   9 #include <linux/errno.h>
  10 #include <linux/buffer_head.h>
  11 #include <linux/kernel.h>
  12 #include <linux/pagemap.h>
  13 #include <linux/reiserfs_fs_sb.h>
  14 #include <linux/reiserfs_fs_i.h>
  15 #include <linux/quotaops.h>
  16
  17 #define PREALLOCATION_SIZE 9
  18
  19 /* different reiserfs block allocator options */
  20
  21 #define SB_ALLOC_OPTS(s) (REISERFS_SB(s)->s_alloc_options.bits)
  22
  23 #define  _ALLOC_concentrating_formatted_nodes 0
  24 #define  _ALLOC_displacing_large_files 1
  25 #define  _ALLOC_displacing_new_packing_localities 2
  26 #define  _ALLOC_old_hashed_relocation 3
  27 #define  _ALLOC_new_hashed_relocation 4
  28 #define  _ALLOC_skip_busy 5
  29 #define  _ALLOC_displace_based_on_dirid 6
  30 #define  _ALLOC_hashed_formatted_nodes 7
  31 #define  _ALLOC_old_way 8
  32 #define  _ALLOC_hundredth_slices 9
  33 #define  _ALLOC_dirid_groups 10
  34 #define  _ALLOC_oid_groups 11
  35 #define  _ALLOC_packing_groups 12
  36
  37 #define  concentrating_formatted_nodes(s)       test_bit(_ALLOC_concentrating_formatted_nodes, &SB_ALLOC_OPTS(s))
  38 #define  displacing_large_files(s)              test_bit(_ALLOC_displacing_large_files, &SB_ALLOC_OPTS(s))
  39 #define  displacing_new_packing_localities(s)   test_bit(_ALLOC_displacing_new_packing_localities, &SB_ALLOC_OPTS(s))
  40
  41 #define SET_OPTION(optname) \
  42    do { \
  43         reiserfs_warning(s, "reiserfs: option \"%s\" is set", #optname); \
  44         set_bit(_ALLOC_ ## optname , &SB_ALLOC_OPTS(s)); \
  45     } while(0)
  46 #define TEST_OPTION(optname, s) \
  47     test_bit(_ALLOC_ ## optname , &SB_ALLOC_OPTS(s))
  48
  49 static inline void get_bit_address(struct super_block *s,
  50                                    b_blocknr_t block, int *bmap_nr, int *offset)
  51 {
  52         /* It is in the bitmap block number equal to the block
  53          * number divided by the number of bits in a block. */
  54         *bmap_nr = block / (s->s_blocksize << 3);
  55         /* Within that bitmap block it is located at bit offset *offset. */
  56         *offset = block & ((s->s_blocksize << 3) - 1);
  57         return;
  58 }
  59
  60 #ifdef CONFIG_REISERFS_CHECK
  61 int is_reusable(struct super_block *s, b_blocknr_t block, int bit_value)
  62 {
  63         int i, j;
  64
  65         if (block == 0 || block >= SB_BLOCK_COUNT(s)) {
  66                 reiserfs_warning(s,
  67                                  "vs-4010: is_reusable: block number is out of range %lu (%u)",
  68                                  block, SB_BLOCK_COUNT(s));
  69                 return 0;
  70         }
  71
  72         /* it can't be one of the bitmap blocks */
  73         for (i = 0; i < SB_BMAP_NR(s); i++)
  74                 if (block == SB_AP_BITMAP(s)[i].bh->b_blocknr) {
  75                         reiserfs_warning(s, "vs: 4020: is_reusable: "
  76                                          "bitmap block %lu(%u) can't be freed or reused",
  77                                          block, SB_BMAP_NR(s));
  78                         return 0;
  79                 }
  80
  81         get_bit_address(s, block, &i, &j);
  82
  83         if (i >= SB_BMAP_NR(s)) {
  84                 reiserfs_warning(s,
  85                                  "vs-4030: is_reusable: there is no so many bitmap blocks: "
  86                                  "block=%lu, bitmap_nr=%d", block, i);
  87                 return 0;
  88         }
  89
  90         if ((bit_value == 0 &&
  91              reiserfs_test_le_bit(j, SB_AP_BITMAP(s)[i].bh->b_data)) ||
  92             (bit_value == 1 &&
  93              reiserfs_test_le_bit(j, SB_AP_BITMAP(s)[i].bh->b_data) == 0)) {
  94                 reiserfs_warning(s,
  95                                  "vs-4040: is_reusable: corresponding bit of block %lu does not "
  96                                  "match required value (i==%d, j==%d) test_bit==%d",
  97                                  block, i, j, reiserfs_test_le_bit(j,
  98                                                                    SB_AP_BITMAP
  99                                                                    (s)[i].bh->
 100                                                                    b_data));
 101
 102                 return 0;
 103         }
 104
 105         if (bit_value == 0 && block == SB_ROOT_BLOCK(s)) {
 106                 reiserfs_warning(s,
 107                                  "vs-4050: is_reusable: this is root block (%u), "
 108                                  "it must be busy", SB_ROOT_BLOCK(s));
 109                 return 0;
 110         }
 111
 112         return 1;
 113 }
 114 #endif                          /* CONFIG_REISERFS_CHECK */
 115
 116 /* searches in journal structures for a given block number (bmap, off). If block
 117    is found in reiserfs journal it suggests next free block candidate to test. */
 118 static inline int is_block_in_journal(struct super_block *s, int bmap, int
 119                                       off, int *next)
 120 {
 121         b_blocknr_t tmp;
 122
 123         if (reiserfs_in_journal(s, bmap, off, 1, &tmp)) {
 124                 if (tmp) {      /* hint supplied */
 125                         *next = tmp;
 126                         PROC_INFO_INC(s, scan_bitmap.in_journal_hint);
 127                 } else {
 128                         (*next) = off + 1;      /* inc offset to avoid looping. */
 129                         PROC_INFO_INC(s, scan_bitmap.in_journal_nohint);
 130                 }
 131                 PROC_INFO_INC(s, scan_bitmap.retry);
 132                 return 1;
 133         }
 134         return 0;
 135 }
 136
 137 /* it searches for a window of zero bits with given minimum and maximum lengths in one bitmap
 138  * block; */
 139 static int scan_bitmap_block(struct reiserfs_transaction_handle *th,
 140                              int bmap_n, int *beg, int boundary, int min,
 141                              int max, int unfm)
 142 {
 143         struct super_block *s = th->t_super;
 144         struct reiserfs_bitmap_info *bi = &SB_AP_BITMAP(s)[bmap_n];
 145         int end, next;
 146         int org = *beg;
 147
 148         BUG_ON(!th->t_trans_id);
 149
 150         RFALSE(bmap_n >= SB_BMAP_NR(s), "Bitmap %d is out of range (0..%d)",
 151                bmap_n, SB_BMAP_NR(s) - 1);
 152         PROC_INFO_INC(s, scan_bitmap.bmap);
 153 /* this is unclear and lacks comments, explain how journal bitmaps
 154    work here for the reader.  Convey a sense of the design here. What
 155    is a window? */
 156 /* - I mean `a window of zero bits' as in description of this function - Zam. */
 157
 158         if (!bi) {
 159                 reiserfs_warning(s, "NULL bitmap info pointer for bitmap %d",
 160                                  bmap_n);
 161                 return 0;
 162         }
 163         if (buffer_locked(bi->bh)) {
 164                 PROC_INFO_INC(s, scan_bitmap.wait);
 165                 __wait_on_buffer(bi->bh);
 166         }
 167
 168         while (1) {
 169               cont:
 170                 if (bi->free_count < min)
 171                         return 0;       // No free blocks in this bitmap
 172
 173                 /* search for a first zero bit -- beggining of a window */
 174                 *beg = reiserfs_find_next_zero_le_bit
 175                     ((unsigned long *)(bi->bh->b_data), boundary, *beg);
 176
 177                 if (*beg + min > boundary) {    /* search for a zero bit fails or the rest of bitmap block
 178                                                  * cannot contain a zero window of minimum size */
 179                         return 0;
 180                 }
 181
 182                 if (unfm && is_block_in_journal(s, bmap_n, *beg, beg))
 183                         continue;
 184                 /* first zero bit found; we check next bits */
 185                 for (end = *beg + 1;; end++) {
 186                         if (end >= *beg + max || end >= boundary
 187                             || reiserfs_test_le_bit(end, bi->bh->b_data)) {
 188                                 next = end;
 189                                 break;
 190                         }
 191                         /* finding the other end of zero bit window requires looking into journal structures (in
 192                          * case of searching for free blocks for unformatted nodes) */
 193                         if (unfm && is_block_in_journal(s, bmap_n, end, &next))
 194                                 break;
 195                 }
 196
 197                 /* now (*beg) points to beginning of zero bits window,
 198                  * (end) points to one bit after the window end */
 199                 if (end - *beg >= min) {        /* it seems we have found window of proper size */
 200                         int i;
 201                         reiserfs_prepare_for_journal(s, bi->bh, 1);
 202                         /* try to set all blocks used checking are they still free */
 203                         for (i = *beg; i < end; i++) {
 204                                 /* It seems that we should not check in journal again. */
 205                                 if (reiserfs_test_and_set_le_bit
 206                                     (i, bi->bh->b_data)) {
 207                                         /* bit was set by another process
 208                                          * while we slept in prepare_for_journal() */
 209                                         PROC_INFO_INC(s, scan_bitmap.stolen);
 210                                         if (i >= *beg + min) {  /* we can continue with smaller set of allocated blocks,
 211                                                                  * if length of this set is more or equal to `min' */
 212                                                 end = i;
 213                                                 break;
 214                                         }
 215                                         /* otherwise we clear all bit were set ... */
 216                                         while (--i >= *beg)
 217                                                 reiserfs_test_and_clear_le_bit
 218                                                     (i, bi->bh->b_data);
 219                                         reiserfs_restore_prepared_buffer(s,
 220                                                                          bi->
 221                                                                          bh);
 222                                         *beg = org;
 223                                         /* ... and search again in current block from beginning */
 224                                         goto cont;
 225                                 }
 226                         }
 227                         bi->free_count -= (end - *beg);
 228                         journal_mark_dirty(th, s, bi->bh);
 229
 230                         /* free block count calculation */
 231                         reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s),
 232                                                      1);
 233                         PUT_SB_FREE_BLOCKS(s, SB_FREE_BLOCKS(s) - (end - *beg));
 234                         journal_mark_dirty(th, s, SB_BUFFER_WITH_SB(s));
 235
 236                         return end - (*beg);
 237                 } else {
 238                         *beg = next;
 239                 }
 240         }
 241 }
 242
 243 static int bmap_hash_id(struct super_block *s, u32 id)
 244 {
 245         char *hash_in = NULL;
 246         unsigned long hash;
 247         unsigned bm;
 248
 249         if (id <= 2) {
 250                 bm = 1;
 251         } else {
 252                 hash_in = (char *)(&id);
 253                 hash = keyed_hash(hash_in, 4);
 254                 bm = hash % SB_BMAP_NR(s);
 255                 if (!bm)
 256                         bm = 1;
 257         }
 258         /* this can only be true when SB_BMAP_NR = 1 */
 259         if (bm >= SB_BMAP_NR(s))
 260                 bm = 0;
 261         return bm;
 262 }
 263
 264 /*
 265  * hashes the id and then returns > 0 if the block group for the
 266  * corresponding hash is full
 267  */
 268 static inline int block_group_used(struct super_block *s, u32 id)
 269 {
 270         int bm;
 271         bm = bmap_hash_id(s, id);
 272         if (SB_AP_BITMAP(s)[bm].free_count > ((s->s_blocksize << 3) * 60 / 100)) {
 273                 return 0;
 274         }
 275         return 1;
 276 }
 277
 278 /*
 279  * the packing is returned in disk byte order
 280  */
 281 __le32 reiserfs_choose_packing(struct inode * dir)
 282 {
 283         __le32 packing;
 284         if (TEST_OPTION(packing_groups, dir->i_sb)) {
 285                 u32 parent_dir = le32_to_cpu(INODE_PKEY(dir)->k_dir_id);
 286                 /*
 287                  * some versions of reiserfsck expect packing locality 1 to be
 288                  * special
 289                  */
 290                 if (parent_dir == 1 || block_group_used(dir->i_sb, parent_dir))
 291                         packing = INODE_PKEY(dir)->k_objectid;
 292                 else
 293                         packing = INODE_PKEY(dir)->k_dir_id;
 294         } else
 295                 packing = INODE_PKEY(dir)->k_objectid;
 296         return packing;
 297 }
 298
 299 /* Tries to find contiguous zero bit window (given size) in given region of
 300  * bitmap and place new blocks there. Returns number of allocated blocks. */
 301 static int scan_bitmap(struct reiserfs_transaction_handle *th,
 302                        b_blocknr_t * start, b_blocknr_t finish,
 303                        int min, int max, int unfm, unsigned long file_block)
 304 {
 305         int nr_allocated = 0;
 306         struct super_block *s = th->t_super;
 307         /* find every bm and bmap and bmap_nr in this file, and change them all to bitmap_blocknr
 308          * - Hans, it is not a block number - Zam. */
 309
 310         int bm, off;
 311         int end_bm, end_off;
 312         int off_max = s->s_blocksize << 3;
 313
 314         BUG_ON(!th->t_trans_id);
 315
 316         PROC_INFO_INC(s, scan_bitmap.call);
 317         if (SB_FREE_BLOCKS(s) <= 0)
 318                 return 0;       // No point in looking for more free blocks
 319
 320         get_bit_address(s, *start, &bm, &off);
 321         get_bit_address(s, finish, &end_bm, &end_off);
 322         if (bm > SB_BMAP_NR(s))
 323                 return 0;
 324         if (end_bm > SB_BMAP_NR(s))
 325                 end_bm = SB_BMAP_NR(s);
 326
 327         /* When the bitmap is more than 10% free, anyone can allocate.
 328          * When it's less than 10% free, only files that already use the
 329          * bitmap are allowed. Once we pass 80% full, this restriction
 330          * is lifted.
 331          *
 332          * We do this so that files that grow later still have space close to
 333          * their original allocation. This improves locality, and presumably
 334          * performance as a result.
 335          *
 336          * This is only an allocation policy and does not make up for getting a
 337          * bad hint. Decent hinting must be implemented for this to work well.
 338          */
 339         if (TEST_OPTION(skip_busy, s)
 340             && SB_FREE_BLOCKS(s) > SB_BLOCK_COUNT(s) / 20) {
 341                 for (; bm < end_bm; bm++, off = 0) {
 342                         if ((off && (!unfm || (file_block != 0)))
 343                             || SB_AP_BITMAP(s)[bm].free_count >
 344                             (s->s_blocksize << 3) / 10)
 345                                 nr_allocated =
 346                                     scan_bitmap_block(th, bm, &off, off_max,
 347                                                       min, max, unfm);
 348                         if (nr_allocated)
 349                                 goto ret;
 350                 }
 351                 /* we know from above that start is a reasonable number */
 352                 get_bit_address(s, *start, &bm, &off);
 353         }
 354
 355         for (; bm < end_bm; bm++, off = 0) {
 356                 nr_allocated =
 357                     scan_bitmap_block(th, bm, &off, off_max, min, max, unfm);
 358                 if (nr_allocated)
 359                         goto ret;
 360         }
 361
 362         nr_allocated =
 363             scan_bitmap_block(th, bm, &off, end_off + 1, min, max, unfm);
 364
 365       ret:
 366         *start = bm * off_max + off;
 367         return nr_allocated;
 368
 369 }
 370
 371 static void _reiserfs_free_block(struct reiserfs_transaction_handle *th,
 372                                  struct inode *inode, b_blocknr_t block,
 373                                  int for_unformatted)
 374 {
 375         struct super_block *s = th->t_super;
 376         struct reiserfs_super_block *rs;
 377         struct buffer_head *sbh;
 378         struct reiserfs_bitmap_info *apbi;
 379         int nr, offset;
 380
 381         BUG_ON(!th->t_trans_id);
 382
 383         PROC_INFO_INC(s, free_block);
 384
 385         rs = SB_DISK_SUPER_BLOCK(s);
 386         sbh = SB_BUFFER_WITH_SB(s);
 387         apbi = SB_AP_BITMAP(s);
 388
 389         get_bit_address(s, block, &nr, &offset);
 390
 391         if (nr >= sb_bmap_nr(rs)) {
 392                 reiserfs_warning(s, "vs-4075: reiserfs_free_block: "
 393                                  "block %lu is out of range on %s",
 394                                  block, reiserfs_bdevname(s));
 395                 return;
 396         }
 397
 398         reiserfs_prepare_for_journal(s, apbi[nr].bh, 1);
 399
 400         /* clear bit for the given block in bit map */
 401         if (!reiserfs_test_and_clear_le_bit(offset, apbi[nr].bh->b_data)) {
 402                 reiserfs_warning(s, "vs-4080: reiserfs_free_block: "
 403                                  "free_block (%s:%lu)[dev:blocknr]: bit already cleared",
 404                                  reiserfs_bdevname(s), block);
 405         }
 406         apbi[nr].free_count++;
 407         journal_mark_dirty(th, s, apbi[nr].bh);
 408
 409         reiserfs_prepare_for_journal(s, sbh, 1);
 410         /* update super block */
 411         set_sb_free_blocks(rs, sb_free_blocks(rs) + 1);
 412
 413         journal_mark_dirty(th, s, sbh);
 414         if (for_unformatted)
 415                 DQUOT_FREE_BLOCK_NODIRTY(inode, 1);
 416 }
 417
 418 void reiserfs_free_block(struct reiserfs_transaction_handle *th,
 419                          struct inode *inode, b_blocknr_t block,
 420                          int for_unformatted)
 421 {
 422         struct super_block *s = th->t_super;
 423
 424         BUG_ON(!th->t_trans_id);
 425
 426         RFALSE(!s, "vs-4061: trying to free block on nonexistent device");
 427         RFALSE(is_reusable(s, block, 1) == 0,
 428                "vs-4071: can not free such block");
 429         /* mark it before we clear it, just in case */
 430         journal_mark_freed(th, s, block);
 431         _reiserfs_free_block(th, inode, block, for_unformatted);
 432 }
 433
 434 /* preallocated blocks don't need to be run through journal_mark_freed */
 435 static void reiserfs_free_prealloc_block(struct reiserfs_transaction_handle *th,
 436                                          struct inode *inode, b_blocknr_t block)
 437 {
 438         RFALSE(!th->t_super,
 439                "vs-4060: trying to free block on nonexistent device");
 440         RFALSE(is_reusable(th->t_super, block, 1) == 0,
 441                "vs-4070: can not free such block");
 442         BUG_ON(!th->t_trans_id);
 443         _reiserfs_free_block(th, inode, block, 1);
 444 }
 445
 446 static void __discard_prealloc(struct reiserfs_transaction_handle *th,
 447                                struct reiserfs_inode_info *ei)
 448 {
 449         unsigned long save = ei->i_prealloc_block;
 450         int dirty = 0;
 451         struct inode *inode = &ei->vfs_inode;
 452         BUG_ON(!th->t_trans_id);
 453 #ifdef CONFIG_REISERFS_CHECK
 454         if (ei->i_prealloc_count < 0)
 455                 reiserfs_warning(th->t_super,
 456                                  "zam-4001:%s: inode has negative prealloc blocks count.",
 457                                  __FUNCTION__);
 458 #endif
 459         while (ei->i_prealloc_count > 0) {
 460                 reiserfs_free_prealloc_block(th, inode, ei->i_prealloc_block);
 461                 ei->i_prealloc_block++;
 462                 ei->i_prealloc_count--;
 463                 dirty = 1;
 464         }
 465         if (dirty)
 466                 reiserfs_update_sd(th, inode);
 467         ei->i_prealloc_block = save;
 468         list_del_init(&(ei->i_prealloc_list));
 469 }
 470
 471 /* FIXME: It should be inline function */
 472 void reiserfs_discard_prealloc(struct reiserfs_transaction_handle *th,
 473                                struct inode *inode)
 474 {
 475         struct reiserfs_inode_info *ei = REISERFS_I(inode);
 476         BUG_ON(!th->t_trans_id);
 477         if (ei->i_prealloc_count)
 478                 __discard_prealloc(th, ei);
 479 }
 480
 481 void reiserfs_discard_all_prealloc(struct reiserfs_transaction_handle *th)
 482 {
 483         struct list_head *plist = &SB_JOURNAL(th->t_super)->j_prealloc_list;
 484
 485         BUG_ON(!th->t_trans_id);
 486
 487         while (!list_empty(plist)) {
 488                 struct reiserfs_inode_info *ei;
 489                 ei = list_entry(plist->next, struct reiserfs_inode_info,
 490                                 i_prealloc_list);
 491 #ifdef CONFIG_REISERFS_CHECK
 492                 if (!ei->i_prealloc_count) {
 493                         reiserfs_warning(th->t_super,
 494                                          "zam-4001:%s: inode is in prealloc list but has no preallocated blocks.",
 495                                          __FUNCTION__);
 496                 }
 497 #endif
 498                 __discard_prealloc(th, ei);
 499         }
 500 }
 501
 502 void reiserfs_init_alloc_options(struct super_block *s)
 503 {
 504         set_bit(_ALLOC_skip_busy, &SB_ALLOC_OPTS(s));
 505         set_bit(_ALLOC_dirid_groups, &SB_ALLOC_OPTS(s));
 506         set_bit(_ALLOC_packing_groups, &SB_ALLOC_OPTS(s));
 507 }
 508
 509 /* block allocator related options are parsed here */
 510 int reiserfs_parse_alloc_options(struct super_block *s, char *options)
 511 {
 512         char *this_char, *value;
 513
 514         REISERFS_SB(s)->s_alloc_options.bits = 0;       /* clear default settings */
 515
 516         while ((this_char = strsep(&options, ":")) != NULL) {
 517                 if ((value = strchr(this_char, '=')) != NULL)
 518                         *value++ = 0;
 519
 520                 if (!strcmp(this_char, "concentrating_formatted_nodes")) {
 521                         int temp;
 522                         SET_OPTION(concentrating_formatted_nodes);
 523                         temp = (value
 524                                 && *value) ? simple_strtoul(value, &value,
 525                                                             0) : 10;
 526                         if (temp <= 0 || temp > 100) {
 527                                 REISERFS_SB(s)->s_alloc_options.border = 10;
 528                         } else {
 529                                 REISERFS_SB(s)->s_alloc_options.border =
 530                                     100 / temp;
 531                         }
 532                         continue;
 533                 }
 534                 if (!strcmp(this_char, "displacing_large_files")) {
 535                         SET_OPTION(displacing_large_files);
 536                         REISERFS_SB(s)->s_alloc_options.large_file_size =
 537                             (value
 538                              && *value) ? simple_strtoul(value, &value, 0) : 16;
 539                         continue;
 540                 }
 541                 if (!strcmp(this_char, "displacing_new_packing_localities")) {
 542                         SET_OPTION(displacing_new_packing_localities);
 543                         continue;
 544                 };
 545
 546                 if (!strcmp(this_char, "old_hashed_relocation")) {
 547                         SET_OPTION(old_hashed_relocation);
 548                         continue;
 549                 }
 550
 551                 if (!strcmp(this_char, "new_hashed_relocation")) {
 552                         SET_OPTION(new_hashed_relocation);
 553                         continue;
 554                 }
 555
 556                 if (!strcmp(this_char, "dirid_groups")) {
 557                         SET_OPTION(dirid_groups);
 558                         continue;
 559                 }
 560                 if (!strcmp(this_char, "oid_groups")) {
 561                         SET_OPTION(oid_groups);
 562                         continue;
 563                 }
 564                 if (!strcmp(this_char, "packing_groups")) {
 565                         SET_OPTION(packing_groups);
 566                         continue;
 567                 }
 568                 if (!strcmp(this_char, "hashed_formatted_nodes")) {
 569                         SET_OPTION(hashed_formatted_nodes);
 570                         continue;
 571                 }
 572
 573                 if (!strcmp(this_char, "skip_busy")) {
 574                         SET_OPTION(skip_busy);
 575                         continue;
 576                 }
 577
 578                 if (!strcmp(this_char, "hundredth_slices")) {
 579                         SET_OPTION(hundredth_slices);
 580                         continue;
 581                 }
 582
 583                 if (!strcmp(this_char, "old_way")) {
 584                         SET_OPTION(old_way);
 585                         continue;
 586                 }
 587
 588                 if (!strcmp(this_char, "displace_based_on_dirid")) {
 589                         SET_OPTION(displace_based_on_dirid);
 590                         continue;
 591                 }
 592
 593                 if (!strcmp(this_char, "preallocmin")) {
 594                         REISERFS_SB(s)->s_alloc_options.preallocmin =
 595                             (value
 596                              && *value) ? simple_strtoul(value, &value, 0) : 4;
 597                         continue;
 598                 }
 599
 600                 if (!strcmp(this_char, "preallocsize")) {
 601                         REISERFS_SB(s)->s_alloc_options.preallocsize =
 602                             (value
 603                              && *value) ? simple_strtoul(value, &value,
 604                                                          0) :
 605                             PREALLOCATION_SIZE;
 606                         continue;
 607                 }
 608
 609                 reiserfs_warning(s, "zam-4001: %s : unknown option - %s",
 610                                  __FUNCTION__, this_char);
 611                 return 1;
 612         }
 613
 614         reiserfs_warning(s, "allocator options = [%08x]\n", SB_ALLOC_OPTS(s));
 615         return 0;
 616 }
 617
 618 static inline void new_hashed_relocation(reiserfs_blocknr_hint_t * hint)
 619 {
 620         char *hash_in;
 621         if (hint->formatted_node) {
 622                 hash_in = (char *)&hint->key.k_dir_id;
 623         } else {
 624                 if (!hint->inode) {
 625                         //hint->search_start = hint->beg;
 626                         hash_in = (char *)&hint->key.k_dir_id;
 627                 } else
 628                     if (TEST_OPTION(displace_based_on_dirid, hint->th->t_super))
 629                         hash_in = (char *)(&INODE_PKEY(hint->inode)->k_dir_id);
 630                 else
 631                         hash_in =
 632                             (char *)(&INODE_PKEY(hint->inode)->k_objectid);
 633         }
 634
 635         hint->search_start =
 636             hint->beg + keyed_hash(hash_in, 4) % (hint->end - hint->beg);
 637 }
 638
 639 /*
 640  * Relocation based on dirid, hashing them into a given bitmap block
 641  * files. Formatted nodes are unaffected, a seperate policy covers them
 642  */
 643 static void dirid_groups(reiserfs_blocknr_hint_t * hint)
 644 {
 645         unsigned long hash;
 646         __u32 dirid = 0;
 647         int bm = 0;
 648         struct super_block *sb = hint->th->t_super;
 649         if (hint->inode)
 650                 dirid = le32_to_cpu(INODE_PKEY(hint->inode)->k_dir_id);
 651         else if (hint->formatted_node)
 652                 dirid = hint->key.k_dir_id;
 653
 654         if (dirid) {
 655                 bm = bmap_hash_id(sb, dirid);
 656                 hash = bm * (sb->s_blocksize << 3);
 657                 /* give a portion of the block group to metadata */
 658                 if (hint->inode)
 659                         hash += sb->s_blocksize / 2;
 660                 hint->search_start = hash;
 661         }
 662 }
 663
 664 /*
 665  * Relocation based on oid, hashing them into a given bitmap block
 666  * files. Formatted nodes are unaffected, a seperate policy covers them
 667  */
 668 static void oid_groups(reiserfs_blocknr_hint_t * hint)
 669 {
 670         if (hint->inode) {
 671                 unsigned long hash;
 672                 __u32 oid;
 673                 __u32 dirid;
 674                 int bm;
 675
 676                 dirid = le32_to_cpu(INODE_PKEY(hint->inode)->k_dir_id);
 677
 678                 /* keep the root dir and it's first set of subdirs close to
 679                  * the start of the disk
 680                  */
 681                 if (dirid <= 2)
 682                         hash = (hint->inode->i_sb->s_blocksize << 3);
 683                 else {
 684                         oid = le32_to_cpu(INODE_PKEY(hint->inode)->k_objectid);
 685                         bm = bmap_hash_id(hint->inode->i_sb, oid);
 686                         hash = bm * (hint->inode->i_sb->s_blocksize << 3);
 687                 }
 688                 hint->search_start = hash;
 689         }
 690 }
 691
 692 /* returns 1 if it finds an indirect item and gets valid hint info
 693  * from it, otherwise 0
 694  */
 695 static int get_left_neighbor(reiserfs_blocknr_hint_t * hint)
 696 {
 697         struct path *path;
 698         struct buffer_head *bh;
 699         struct item_head *ih;
 700         int pos_in_item;
 701         __le32 *item;
 702         int ret = 0;
 703
 704         if (!hint->path)        /* reiserfs code can call this function w/o pointer to path
 705                                  * structure supplied; then we rely on supplied search_start */
 706                 return 0;
 707
 708         path = hint->path;
 709         bh = get_last_bh(path);
 710         RFALSE(!bh, "green-4002: Illegal path specified to get_left_neighbor");
 711         ih = get_ih(path);
 712         pos_in_item = path->pos_in_item;
 713         item = get_item(path);
 714
 715         hint->search_start = bh->b_blocknr;
 716
 717         if (!hint->formatted_node && is_indirect_le_ih(ih)) {
 718                 /* for indirect item: go to left and look for the first non-hole entry
 719                    in the indirect item */
 720                 if (pos_in_item == I_UNFM_NUM(ih))
 721                         pos_in_item--;
 722 //          pos_in_item = I_UNFM_NUM (ih) - 1;
 723                 while (pos_in_item >= 0) {
 724                         int t = get_block_num(item, pos_in_item);
 725                         if (t) {
 726                                 hint->search_start = t;
 727                                 ret = 1;
 728                                 break;
 729                         }
 730                         pos_in_item--;
 731                 }
 732         }
 733
 734         /* does result value fit into specified region? */
 735         return ret;
 736 }
 737
 738 /* should be, if formatted node, then try to put on first part of the device
 739    specified as number of percent with mount option device, else try to put
 740    on last of device.  This is not to say it is good code to do so,
 741    but the effect should be measured.  */
 742 static inline void set_border_in_hint(struct super_block *s,
 743                                       reiserfs_blocknr_hint_t * hint)
 744 {
 745         b_blocknr_t border =
 746             SB_BLOCK_COUNT(s) / REISERFS_SB(s)->s_alloc_options.border;
 747
 748         if (hint->formatted_node)
 749                 hint->end = border - 1;
 750         else
 751                 hint->beg = border;
 752 }
 753
 754 static inline void displace_large_file(reiserfs_blocknr_hint_t * hint)
 755 {
 756         if (TEST_OPTION(displace_based_on_dirid, hint->th->t_super))
 757                 hint->search_start =
 758                     hint->beg +
 759                     keyed_hash((char *)(&INODE_PKEY(hint->inode)->k_dir_id),
 760                                4) % (hint->end - hint->beg);
 761         else
 762                 hint->search_start =
 763                     hint->beg +
 764                     keyed_hash((char *)(&INODE_PKEY(hint->inode)->k_objectid),
 765                                4) % (hint->end - hint->beg);
 766 }
 767
 768 static inline void hash_formatted_node(reiserfs_blocknr_hint_t * hint)
 769 {
 770         char *hash_in;
 771
 772         if (!hint->inode)
 773                 hash_in = (char *)&hint->key.k_dir_id;
 774         else if (TEST_OPTION(displace_based_on_dirid, hint->th->t_super))
 775                 hash_in = (char *)(&INODE_PKEY(hint->inode)->k_dir_id);
 776         else
 777                 hash_in = (char *)(&INODE_PKEY(hint->inode)->k_objectid);
 778
 779         hint->search_start =
 780             hint->beg + keyed_hash(hash_in, 4) % (hint->end - hint->beg);
 781 }
 782
 783 static inline int
 784 this_blocknr_allocation_would_make_it_a_large_file(reiserfs_blocknr_hint_t *
 785                                                    hint)
 786 {
 787         return hint->block ==
 788             REISERFS_SB(hint->th->t_super)->s_alloc_options.large_file_size;
 789 }
 790
 791 #ifdef DISPLACE_NEW_PACKING_LOCALITIES
 792 static inline void displace_new_packing_locality(reiserfs_blocknr_hint_t * hint)
 793 {
 794         struct in_core_key *key = &hint->key;
 795
 796         hint->th->displace_new_blocks = 0;
 797         hint->search_start =
 798             hint->beg + keyed_hash((char *)(&key->k_objectid),
 799                                    4) % (hint->end - hint->beg);
 800 }
 801 #endif
 802
 803 static inline int old_hashed_relocation(reiserfs_blocknr_hint_t * hint)
 804 {
 805         b_blocknr_t border;
 806         u32 hash_in;
 807
 808         if (hint->formatted_node || hint->inode == NULL) {
 809                 return 0;
 810         }
 811
 812         hash_in = le32_to_cpu((INODE_PKEY(hint->inode))->k_dir_id);
 813         border =
 814             hint->beg + (u32) keyed_hash(((char *)(&hash_in)),
 815                                          4) % (hint->end - hint->beg - 1);
 816         if (border > hint->search_start)
 817                 hint->search_start = border;
 818
 819         return 1;
 820 }
 821
 822 static inline int old_way(reiserfs_blocknr_hint_t * hint)
 823 {
 824         b_blocknr_t border;
 825
 826         if (hint->formatted_node || hint->inode == NULL) {
 827                 return 0;
 828         }
 829
 830         border =
 831             hint->beg +
 832             le32_to_cpu(INODE_PKEY(hint->inode)->k_dir_id) % (hint->end -
 833                                                               hint->beg);
 834         if (border > hint->search_start)
 835                 hint->search_start = border;
 836
 837         return 1;
 838 }
 839
 840 static inline void hundredth_slices(reiserfs_blocknr_hint_t * hint)
 841 {
 842         struct in_core_key *key = &hint->key;
 843         b_blocknr_t slice_start;
 844
 845         slice_start =
 846             (keyed_hash((char *)(&key->k_dir_id), 4) % 100) * (hint->end / 100);
 847         if (slice_start > hint->search_start
 848             || slice_start + (hint->end / 100) <= hint->search_start) {
 849                 hint->search_start = slice_start;
 850         }
 851 }
 852
 853 static void determine_search_start(reiserfs_blocknr_hint_t * hint,
 854                                    int amount_needed)
 855 {
 856         struct super_block *s = hint->th->t_super;
 857         int unfm_hint;
 858
 859         hint->beg = 0;
 860         hint->end = SB_BLOCK_COUNT(s) - 1;
 861
 862         /* This is former border algorithm. Now with tunable border offset */
 863         if (concentrating_formatted_nodes(s))
 864                 set_border_in_hint(s, hint);
 865
 866 #ifdef DISPLACE_NEW_PACKING_LOCALITIES
 867         /* whenever we create a new directory, we displace it.  At first we will
 868            hash for location, later we might look for a moderately empty place for
 869            it */
 870         if (displacing_new_packing_localities(s)
 871             && hint->th->displace_new_blocks) {
 872                 displace_new_packing_locality(hint);
 873
 874                 /* we do not continue determine_search_start,
 875                  * if new packing locality is being displaced */
 876                 return;
 877         }
 878 #endif
 879
 880         /* all persons should feel encouraged to add more special cases here and
 881          * test them */
 882
 883         if (displacing_large_files(s) && !hint->formatted_node
 884             && this_blocknr_allocation_would_make_it_a_large_file(hint)) {
 885                 displace_large_file(hint);
 886                 return;
 887         }
 888
 889         /* if none of our special cases is relevant, use the left neighbor in the
 890            tree order of the new node we are allocating for */
 891         if (hint->formatted_node && TEST_OPTION(hashed_formatted_nodes, s)) {
 892                 hash_formatted_node(hint);
 893                 return;
 894         }
 895
 896         unfm_hint = get_left_neighbor(hint);
 897
 898         /* Mimic old block allocator behaviour, that is if VFS allowed for preallocation,
 899            new blocks are displaced based on directory ID. Also, if suggested search_start
 900            is less than last preallocated block, we start searching from it, assuming that
 901            HDD dataflow is faster in forward direction */
 902         if (TEST_OPTION(old_way, s)) {
 903                 if (!hint->formatted_node) {
 904                         if (!reiserfs_hashed_relocation(s))
 905                                 old_way(hint);
 906                         else if (!reiserfs_no_unhashed_relocation(s))
 907                                 old_hashed_relocation(hint);
 908
 909                         if (hint->inode
 910                             && hint->search_start <
 911                             REISERFS_I(hint->inode)->i_prealloc_block)
 912                                 hint->search_start =
 913                                     REISERFS_I(hint->inode)->i_prealloc_block;
 914                 }
 915                 return;
 916         }
 917
 918         /* This is an approach proposed by Hans */
 919         if (TEST_OPTION(hundredth_slices, s)
 920             && !(displacing_large_files(s) && !hint->formatted_node)) {
 921                 hundredth_slices(hint);
 922                 return;
 923         }
 924
 925         /* old_hashed_relocation only works on unformatted */
 926         if (!unfm_hint && !hint->formatted_node &&
 927             TEST_OPTION(old_hashed_relocation, s)) {
 928                 old_hashed_relocation(hint);
 929         }
 930         /* new_hashed_relocation works with both formatted/unformatted nodes */
 931         if ((!unfm_hint || hint->formatted_node) &&
 932             TEST_OPTION(new_hashed_relocation, s)) {
 933                 new_hashed_relocation(hint);
 934         }
 935         /* dirid grouping works only on unformatted nodes */
 936         if (!unfm_hint && !hint->formatted_node && TEST_OPTION(dirid_groups, s)) {
 937                 dirid_groups(hint);
 938         }
 939 #ifdef DISPLACE_NEW_PACKING_LOCALITIES
 940         if (hint->formatted_node && TEST_OPTION(dirid_groups, s)) {
 941                 dirid_groups(hint);
 942         }
 943 #endif
 944
 945         /* oid grouping works only on unformatted nodes */
 946         if (!unfm_hint && !hint->formatted_node && TEST_OPTION(oid_groups, s)) {
 947                 oid_groups(hint);
 948         }
 949         return;
 950 }
 951
 952 static int determine_prealloc_size(reiserfs_blocknr_hint_t * hint)
 953 {
 954         /* make minimum size a mount option and benchmark both ways */
 955         /* we preallocate blocks only for regular files, specific size */
 956         /* benchmark preallocating always and see what happens */
 957
 958         hint->prealloc_size = 0;
 959
 960         if (!hint->formatted_node && hint->preallocate) {
 961                 if (S_ISREG(hint->inode->i_mode)
 962                     && hint->inode->i_size >=
 963                     REISERFS_SB(hint->th->t_super)->s_alloc_options.
 964                     preallocmin * hint->inode->i_sb->s_blocksize)
 965                         hint->prealloc_size =
 966                             REISERFS_SB(hint->th->t_super)->s_alloc_options.
 967                             preallocsize - 1;
 968         }
 969         return CARRY_ON;
 970 }
 971
 972 /* XXX I know it could be merged with upper-level function;
 973    but may be result function would be too complex. */
 974 static inline int allocate_without_wrapping_disk(reiserfs_blocknr_hint_t * hint,
 975                                                  b_blocknr_t * new_blocknrs,
 976                                                  b_blocknr_t start,
 977                                                  b_blocknr_t finish, int min,
 978                                                  int amount_needed,
 979                                                  int prealloc_size)
 980 {
 981         int rest = amount_needed;
 982         int nr_allocated;
 983
 984         while (rest > 0 && start <= finish) {
 985                 nr_allocated = scan_bitmap(hint->th, &start, finish, min,
 986                                            rest + prealloc_size,
 987                                            !hint->formatted_node, hint->block);
 988
 989                 if (nr_allocated == 0)  /* no new blocks allocated, return */
 990                         break;
 991
 992                 /* fill free_blocknrs array first */
 993                 while (rest > 0 && nr_allocated > 0) {
 994                         *new_blocknrs++ = start++;
 995                         rest--;
 996                         nr_allocated--;
 997                 }
 998
 999                 /* do we have something to fill prealloc. array also ? */
1000                 if (nr_allocated > 0) {
1001                         /* it means prealloc_size was greater that 0 and we do preallocation */
1002                         list_add(&REISERFS_I(hint->inode)->i_prealloc_list,
1003                                  &SB_JOURNAL(hint->th->t_super)->
1004                                  j_prealloc_list);
1005                         REISERFS_I(hint->inode)->i_prealloc_block = start;
1006                         REISERFS_I(hint->inode)->i_prealloc_count =
1007                             nr_allocated;
1008                         break;
1009                 }
1010         }
1011
1012         return (amount_needed - rest);
1013 }
1014
1015 static inline int blocknrs_and_prealloc_arrays_from_search_start
1016     (reiserfs_blocknr_hint_t * hint, b_blocknr_t * new_blocknrs,
1017      int amount_needed) {
1018         struct super_block *s = hint->th->t_super;
1019         b_blocknr_t start = hint->search_start;
1020         b_blocknr_t finish = SB_BLOCK_COUNT(s) - 1;
1021         int passno = 0;
1022         int nr_allocated = 0;
1023         int bigalloc = 0;
1024
1025         determine_prealloc_size(hint);
1026         if (!hint->formatted_node) {
1027                 int quota_ret;
1028 #ifdef REISERQUOTA_DEBUG
1029                 reiserfs_debug(s, REISERFS_DEBUG_CODE,
1030                                "reiserquota: allocating %d blocks id=%u",
1031                                amount_needed, hint->inode->i_uid);
1032 #endif
1033                 quota_ret =
1034                     DQUOT_ALLOC_BLOCK_NODIRTY(hint->inode, amount_needed);
1035                 if (quota_ret)  /* Quota exceeded? */
1036                         return QUOTA_EXCEEDED;
1037                 if (hint->preallocate && hint->prealloc_size) {
1038 #ifdef REISERQUOTA_DEBUG
1039                         reiserfs_debug(s, REISERFS_DEBUG_CODE,
1040                                        "reiserquota: allocating (prealloc) %d blocks id=%u",
1041                                        hint->prealloc_size, hint->inode->i_uid);
1042 #endif
1043                         quota_ret =
1044                             DQUOT_PREALLOC_BLOCK_NODIRTY(hint->inode,
1045                                                          hint->prealloc_size);
1046                         if (quota_ret)
1047                                 hint->preallocate = hint->prealloc_size = 0;
1048                 }
1049                 /* for unformatted nodes, force large allocations */
1050                 bigalloc = amount_needed;
1051         }
1052
1053         do {
1054                 /* in bigalloc mode, nr_allocated should stay zero until
1055                  * the entire allocation is filled
1056                  */
1057                 if (unlikely(bigalloc && nr_allocated)) {
1058                         reiserfs_warning(s, "bigalloc is %d, nr_allocated %d\n",
1059                                          bigalloc, nr_allocated);
1060                         /* reset things to a sane value */
1061                         bigalloc = amount_needed - nr_allocated;
1062                 }
1063                 /*
1064                  * try pass 0 and pass 1 looking for a nice big
1065                  * contiguous allocation.  Then reset and look
1066                  * for anything you can find.
1067                  */
1068                 if (passno == 2 && bigalloc) {
1069                         passno = 0;
1070                         bigalloc = 0;
1071                 }
1072                 switch (passno++) {
1073                 case 0: /* Search from hint->search_start to end of disk */
1074                         start = hint->search_start;
1075                         finish = SB_BLOCK_COUNT(s) - 1;
1076                         break;
1077                 case 1: /* Search from hint->beg to hint->search_start */
1078                         start = hint->beg;
1079                         finish = hint->search_start;
1080                         break;
1081                 case 2: /* Last chance: Search from 0 to hint->beg */
1082                         start = 0;
1083                         finish = hint->beg;
1084                         break;
1085                 default:        /* We've tried searching everywhere, not enough space */
1086                         /* Free the blocks */
1087                         if (!hint->formatted_node) {
1088 #ifdef REISERQUOTA_DEBUG
1089                                 reiserfs_debug(s, REISERFS_DEBUG_CODE,
1090                                                "reiserquota: freeing (nospace) %d blocks id=%u",
1091                                                amount_needed +
1092                                                hint->prealloc_size -
1093                                                nr_allocated,
1094                                                hint->inode->i_uid);
1095 #endif
1096                                 DQUOT_FREE_BLOCK_NODIRTY(hint->inode, amount_needed + hint->prealloc_size - nr_allocated);      /* Free not allocated blocks */
1097                         }
1098                         while (nr_allocated--)
1099                                 reiserfs_free_block(hint->th, hint->inode,
1100                                                     new_blocknrs[nr_allocated],
1101                                                     !hint->formatted_node);
1102
1103                         return NO_DISK_SPACE;
1104                 }
1105         } while ((nr_allocated += allocate_without_wrapping_disk(hint,
1106                                                                  new_blocknrs +
1107                                                                  nr_allocated,
1108                                                                  start, finish,
1109                                                                  bigalloc ?
1110                                                                  bigalloc : 1,
1111                                                                  amount_needed -
1112                                                                  nr_allocated,
1113                                                                  hint->
1114                                                                  prealloc_size))
1115                  < amount_needed);
1116         if (!hint->formatted_node &&
1117             amount_needed + hint->prealloc_size >
1118             nr_allocated + REISERFS_I(hint->inode)->i_prealloc_count) {
1119                 /* Some of preallocation blocks were not allocated */
1120 #ifdef REISERQUOTA_DEBUG
1121                 reiserfs_debug(s, REISERFS_DEBUG_CODE,
1122                                "reiserquota: freeing (failed prealloc) %d blocks id=%u",
1123                                amount_needed + hint->prealloc_size -
1124                                nr_allocated -
1125                                REISERFS_I(hint->inode)->i_prealloc_count,
1126                                hint->inode->i_uid);
1127 #endif
1128                 DQUOT_FREE_BLOCK_NODIRTY(hint->inode, amount_needed +
1129                                          hint->prealloc_size - nr_allocated -
1130                                          REISERFS_I(hint->inode)->
1131                                          i_prealloc_count);
1132         }
1133
1134         return CARRY_ON;
1135 }
1136
1137 /* grab new blocknrs from preallocated list */
1138 /* return amount still needed after using them */
1139 static int use_preallocated_list_if_available(reiserfs_blocknr_hint_t * hint,
1140                                               b_blocknr_t * new_blocknrs,
1141                                               int amount_needed)
1142 {
1143         struct inode *inode = hint->inode;
1144
1145         if (REISERFS_I(inode)->i_prealloc_count > 0) {
1146                 while (amount_needed) {
1147
1148                         *new_blocknrs++ = REISERFS_I(inode)->i_prealloc_block++;
1149                         REISERFS_I(inode)->i_prealloc_count--;
1150
1151                         amount_needed--;
1152
1153                         if (REISERFS_I(inode)->i_prealloc_count <= 0) {
1154                                 list_del(&REISERFS_I(inode)->i_prealloc_list);
1155                                 break;
1156                         }
1157                 }
1158         }
1159         /* return amount still needed after using preallocated blocks */
1160         return amount_needed;
1161 }
1162
1163 int reiserfs_allocate_blocknrs(reiserfs_blocknr_hint_t * hint, b_blocknr_t * new_blocknrs, int amount_needed, int reserved_by_us        /* Amount of blocks we have
1164                                                                                                                                            already reserved */ )
1165 {
1166         int initial_amount_needed = amount_needed;
1167         int ret;
1168         struct super_block *s = hint->th->t_super;
1169
1170         /* Check if there is enough space, taking into account reserved space */
1171         if (SB_FREE_BLOCKS(s) - REISERFS_SB(s)->reserved_blocks <
1172             amount_needed - reserved_by_us)
1173                 return NO_DISK_SPACE;
1174         /* should this be if !hint->inode &&  hint->preallocate? */
1175         /* do you mean hint->formatted_node can be removed ? - Zam */
1176         /* hint->formatted_node cannot be removed because we try to access
1177            inode information here, and there is often no inode assotiated with
1178            metadata allocations - green */
1179
1180         if (!hint->formatted_node && hint->preallocate) {
1181                 amount_needed = use_preallocated_list_if_available
1182                     (hint, new_blocknrs, amount_needed);
1183                 if (amount_needed == 0) /* all blocknrs we need we got from
1184                                            prealloc. list */
1185                         return CARRY_ON;
1186                 new_blocknrs += (initial_amount_needed - amount_needed);
1187         }
1188
1189         /* find search start and save it in hint structure */
1190         determine_search_start(hint, amount_needed);
1191         if (hint->search_start >= SB_BLOCK_COUNT(s))
1192                 hint->search_start = SB_BLOCK_COUNT(s) - 1;
1193
1194         /* allocation itself; fill new_blocknrs and preallocation arrays */
1195         ret = blocknrs_and_prealloc_arrays_from_search_start
1196             (hint, new_blocknrs, amount_needed);
1197
1198         /* we used prealloc. list to fill (partially) new_blocknrs array. If final allocation fails we
1199          * need to return blocks back to prealloc. list or just free them. -- Zam (I chose second
1200          * variant) */
1201
1202         if (ret != CARRY_ON) {
1203                 while (amount_needed++ < initial_amount_needed) {
1204                         reiserfs_free_block(hint->th, hint->inode,
1205                                             *(--new_blocknrs), 1);
1206                 }
1207         }
1208         return ret;
1209 }
1210
1211 /* These 2 functions are here to provide blocks reservation to the rest of kernel */
1212 /* Reserve @blocks amount of blocks in fs pointed by @sb. Caller must make sure
1213    there are actually this much blocks on the FS available */
1214 void reiserfs_claim_blocks_to_be_allocated(struct super_block *sb,      /* super block of
1215                                                                            filesystem where
1216                                                                            blocks should be
1217                                                                            reserved */
1218                                            int blocks   /* How much to reserve */
1219     )
1220 {
1221
1222         /* Fast case, if reservation is zero - exit immediately. */
1223         if (!blocks)
1224                 return;
1225
1226         spin_lock(&REISERFS_SB(sb)->bitmap_lock);
1227         REISERFS_SB(sb)->reserved_blocks += blocks;
1228         spin_unlock(&REISERFS_SB(sb)->bitmap_lock);
1229 }
1230
1231 /* Unreserve @blocks amount of blocks in fs pointed by @sb */
1232 void reiserfs_release_claimed_blocks(struct super_block *sb,    /* super block of
1233                                                                    filesystem where
1234                                                                    blocks should be
1235                                                                    reserved */
1236                                      int blocks /* How much to unreserve */
1237     )
1238 {
1239
1240         /* Fast case, if unreservation is zero - exit immediately. */
1241         if (!blocks)
1242                 return;
1243
1244         spin_lock(&REISERFS_SB(sb)->bitmap_lock);
1245         REISERFS_SB(sb)->reserved_blocks -= blocks;
1246         spin_unlock(&REISERFS_SB(sb)->bitmap_lock);
1247         RFALSE(REISERFS_SB(sb)->reserved_blocks < 0,
1248                "amount of blocks reserved became zero?");
1249 }
1250
1251 /* This function estimates how much pages we will be able to write to FS
1252    used for reiserfs_file_write() purposes for now. */
1253 int reiserfs_can_fit_pages(struct super_block *sb       /* superblock of filesystem
1254                                                            to estimate space */ )
1255 {
1256         int space;
1257
1258         spin_lock(&REISERFS_SB(sb)->bitmap_lock);
1259         space =
1260             (SB_FREE_BLOCKS(sb) -
1261              REISERFS_SB(sb)->reserved_blocks) >> (PAGE_CACHE_SHIFT -
1262                                                    sb->s_blocksize_bits);
1263         spin_unlock(&REISERFS_SB(sb)->bitmap_lock);
1264
1265         return space > 0 ? space : 0;
1266 }