fs/ntfs3/bitmap.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *
   4  * Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.
   5  *
   6  * This code builds two trees of free clusters extents.
   7  * Trees are sorted by start of extent and by length of extent.
   8  * NTFS_MAX_WND_EXTENTS defines the maximum number of elements in trees.
   9  * In extreme case code reads on-disk bitmap to find free clusters.
  10  *
  11  */
  12
  13 #include <linux/buffer_head.h>
  14 #include <linux/fs.h>
  15 #include <linux/kernel.h>
  16
  17 #include "ntfs.h"
  18 #include "ntfs_fs.h"
  19
  20 /*
  21  * Maximum number of extents in tree.
  22  */
  23 #define NTFS_MAX_WND_EXTENTS (32u * 1024u)
  24
  25 struct rb_node_key {
  26         struct rb_node node;
  27         size_t key;
  28 };
  29
  30 struct e_node {
  31         struct rb_node_key start; /* Tree sorted by start. */
  32         struct rb_node_key count; /* Tree sorted by len. */
  33 };
  34
  35 static int wnd_rescan(struct wnd_bitmap *wnd);
  36 static struct buffer_head *wnd_map(struct wnd_bitmap *wnd, size_t iw);
  37 static bool wnd_is_free_hlp(struct wnd_bitmap *wnd, size_t bit, size_t bits);
  38
  39 static struct kmem_cache *ntfs_enode_cachep;
  40
  41 int __init ntfs3_init_bitmap(void)
  42 {
  43         ntfs_enode_cachep =
  44                 kmem_cache_create("ntfs3_enode_cache", sizeof(struct e_node), 0,
  45                                   SLAB_RECLAIM_ACCOUNT, NULL);
  46         return ntfs_enode_cachep ? 0 : -ENOMEM;
  47 }
  48
  49 void ntfs3_exit_bitmap(void)
  50 {
  51         kmem_cache_destroy(ntfs_enode_cachep);
  52 }
  53
  54 /*
  55  * wnd_scan
  56  *
  57  * b_pos + b_len - biggest fragment.
  58  * Scan range [wpos wbits) window @buf.
  59  *
  60  * Return: -1 if not found.
  61  */
  62 static size_t wnd_scan(const void *buf, size_t wbit, u32 wpos, u32 wend,
  63                        size_t to_alloc, size_t *prev_tail, size_t *b_pos,
  64                        size_t *b_len)
  65 {
  66         while (wpos < wend) {
  67                 size_t free_len;
  68                 u32 free_bits, end;
  69                 u32 used = find_next_zero_bit_le(buf, wend, wpos);
  70
  71                 if (used >= wend) {
  72                         if (*b_len < *prev_tail) {
  73                                 *b_pos = wbit - *prev_tail;
  74                                 *b_len = *prev_tail;
  75                         }
  76
  77                         *prev_tail = 0;
  78                         return -1;
  79                 }
  80
  81                 if (used > wpos) {
  82                         wpos = used;
  83                         if (*b_len < *prev_tail) {
  84                                 *b_pos = wbit - *prev_tail;
  85                                 *b_len = *prev_tail;
  86                         }
  87
  88                         *prev_tail = 0;
  89                 }
  90
  91                 /*
  92                  * Now we have a fragment [wpos, wend) staring with 0.
  93                  */
  94                 end = wpos + to_alloc - *prev_tail;
  95                 free_bits = find_next_bit_le(buf, min(end, wend), wpos);
  96
  97                 free_len = *prev_tail + free_bits - wpos;
  98
  99                 if (*b_len < free_len) {
 100                         *b_pos = wbit + wpos - *prev_tail;
 101                         *b_len = free_len;
 102                 }
 103
 104                 if (free_len >= to_alloc)
 105                         return wbit + wpos - *prev_tail;
 106
 107                 if (free_bits >= wend) {
 108                         *prev_tail += free_bits - wpos;
 109                         return -1;
 110                 }
 111
 112                 wpos = free_bits + 1;
 113
 114                 *prev_tail = 0;
 115         }
 116
 117         return -1;
 118 }
 119
 120 /*
 121  * wnd_close - Frees all resources.
 122  */
 123 void wnd_close(struct wnd_bitmap *wnd)
 124 {
 125         struct rb_node *node, *next;
 126
 127         kfree(wnd->free_bits);
 128         run_close(&wnd->run);
 129
 130         node = rb_first(&wnd->start_tree);
 131
 132         while (node) {
 133                 next = rb_next(node);
 134                 rb_erase(node, &wnd->start_tree);
 135                 kmem_cache_free(ntfs_enode_cachep,
 136                                 rb_entry(node, struct e_node, start.node));
 137                 node = next;
 138         }
 139 }
 140
 141 static struct rb_node *rb_lookup(struct rb_root *root, size_t v)
 142 {
 143         struct rb_node **p = &root->rb_node;
 144         struct rb_node *r = NULL;
 145
 146         while (*p) {
 147                 struct rb_node_key *k;
 148
 149                 k = rb_entry(*p, struct rb_node_key, node);
 150                 if (v < k->key) {
 151                         p = &(*p)->rb_left;
 152                 } else if (v > k->key) {
 153                         r = &k->node;
 154                         p = &(*p)->rb_right;
 155                 } else {
 156                         return &k->node;
 157                 }
 158         }
 159
 160         return r;
 161 }
 162
 163 /*
 164  * rb_insert_count - Helper function to insert special kind of 'count' tree.
 165  */
 166 static inline bool rb_insert_count(struct rb_root *root, struct e_node *e)
 167 {
 168         struct rb_node **p = &root->rb_node;
 169         struct rb_node *parent = NULL;
 170         size_t e_ckey = e->count.key;
 171         size_t e_skey = e->start.key;
 172
 173         while (*p) {
 174                 struct e_node *k =
 175                         rb_entry(parent = *p, struct e_node, count.node);
 176
 177                 if (e_ckey > k->count.key) {
 178                         p = &(*p)->rb_left;
 179                 } else if (e_ckey < k->count.key) {
 180                         p = &(*p)->rb_right;
 181                 } else if (e_skey < k->start.key) {
 182                         p = &(*p)->rb_left;
 183                 } else if (e_skey > k->start.key) {
 184                         p = &(*p)->rb_right;
 185                 } else {
 186                         WARN_ON(1);
 187                         return false;
 188                 }
 189         }
 190
 191         rb_link_node(&e->count.node, parent, p);
 192         rb_insert_color(&e->count.node, root);
 193         return true;
 194 }
 195
 196 /*
 197  * rb_insert_start - Helper function to insert special kind of 'count' tree.
 198  */
 199 static inline bool rb_insert_start(struct rb_root *root, struct e_node *e)
 200 {
 201         struct rb_node **p = &root->rb_node;
 202         struct rb_node *parent = NULL;
 203         size_t e_skey = e->start.key;
 204
 205         while (*p) {
 206                 struct e_node *k;
 207
 208                 parent = *p;
 209
 210                 k = rb_entry(parent, struct e_node, start.node);
 211                 if (e_skey < k->start.key) {
 212                         p = &(*p)->rb_left;
 213                 } else if (e_skey > k->start.key) {
 214                         p = &(*p)->rb_right;
 215                 } else {
 216                         WARN_ON(1);
 217                         return false;
 218                 }
 219         }
 220
 221         rb_link_node(&e->start.node, parent, p);
 222         rb_insert_color(&e->start.node, root);
 223         return true;
 224 }
 225
 226 /*
 227  * wnd_add_free_ext - Adds a new extent of free space.
 228  * @build:      1 when building tree.
 229  */
 230 static void wnd_add_free_ext(struct wnd_bitmap *wnd, size_t bit, size_t len,
 231                              bool build)
 232 {
 233         struct e_node *e, *e0 = NULL;
 234         size_t ib, end_in = bit + len;
 235         struct rb_node *n;
 236
 237         if (build) {
 238                 /* Use extent_min to filter too short extents. */
 239                 if (wnd->count >= NTFS_MAX_WND_EXTENTS &&
 240                     len <= wnd->extent_min) {
 241                         wnd->uptodated = -1;
 242                         return;
 243                 }
 244         } else {
 245                 /* Try to find extent before 'bit'. */
 246                 n = rb_lookup(&wnd->start_tree, bit);
 247
 248                 if (!n) {
 249                         n = rb_first(&wnd->start_tree);
 250                 } else {
 251                         e = rb_entry(n, struct e_node, start.node);
 252                         n = rb_next(n);
 253                         if (e->start.key + e->count.key == bit) {
 254                                 /* Remove left. */
 255                                 bit = e->start.key;
 256                                 len += e->count.key;
 257                                 rb_erase(&e->start.node, &wnd->start_tree);
 258                                 rb_erase(&e->count.node, &wnd->count_tree);
 259                                 wnd->count -= 1;
 260                                 e0 = e;
 261                         }
 262                 }
 263
 264                 while (n) {
 265                         size_t next_end;
 266
 267                         e = rb_entry(n, struct e_node, start.node);
 268                         next_end = e->start.key + e->count.key;
 269                         if (e->start.key > end_in)
 270                                 break;
 271
 272                         /* Remove right. */
 273                         n = rb_next(n);
 274                         len += next_end - end_in;
 275                         end_in = next_end;
 276                         rb_erase(&e->start.node, &wnd->start_tree);
 277                         rb_erase(&e->count.node, &wnd->count_tree);
 278                         wnd->count -= 1;
 279
 280                         if (!e0)
 281                                 e0 = e;
 282                         else
 283                                 kmem_cache_free(ntfs_enode_cachep, e);
 284                 }
 285
 286                 if (wnd->uptodated != 1) {
 287                         /* Check bits before 'bit'. */
 288                         ib = wnd->zone_bit == wnd->zone_end ||
 289                                              bit < wnd->zone_end
 290                                      ? 0
 291                                      : wnd->zone_end;
 292
 293                         while (bit > ib && wnd_is_free_hlp(wnd, bit - 1, 1)) {
 294                                 bit -= 1;
 295                                 len += 1;
 296                         }
 297
 298                         /* Check bits after 'end_in'. */
 299                         ib = wnd->zone_bit == wnd->zone_end ||
 300                                              end_in > wnd->zone_bit
 301                                      ? wnd->nbits
 302                                      : wnd->zone_bit;
 303
 304                         while (end_in < ib && wnd_is_free_hlp(wnd, end_in, 1)) {
 305                                 end_in += 1;
 306                                 len += 1;
 307                         }
 308                 }
 309         }
 310         /* Insert new fragment. */
 311         if (wnd->count >= NTFS_MAX_WND_EXTENTS) {
 312                 if (e0)
 313                         kmem_cache_free(ntfs_enode_cachep, e0);
 314
 315                 wnd->uptodated = -1;
 316
 317                 /* Compare with smallest fragment. */
 318                 n = rb_last(&wnd->count_tree);
 319                 e = rb_entry(n, struct e_node, count.node);
 320                 if (len <= e->count.key)
 321                         goto out; /* Do not insert small fragments. */
 322
 323                 if (build) {
 324                         struct e_node *e2;
 325
 326                         n = rb_prev(n);
 327                         e2 = rb_entry(n, struct e_node, count.node);
 328                         /* Smallest fragment will be 'e2->count.key'. */
 329                         wnd->extent_min = e2->count.key;
 330                 }
 331
 332                 /* Replace smallest fragment by new one. */
 333                 rb_erase(&e->start.node, &wnd->start_tree);
 334                 rb_erase(&e->count.node, &wnd->count_tree);
 335                 wnd->count -= 1;
 336         } else {
 337                 e = e0 ? e0 : kmem_cache_alloc(ntfs_enode_cachep, GFP_ATOMIC);
 338                 if (!e) {
 339                         wnd->uptodated = -1;
 340                         goto out;
 341                 }
 342
 343                 if (build && len <= wnd->extent_min)
 344                         wnd->extent_min = len;
 345         }
 346         e->start.key = bit;
 347         e->count.key = len;
 348         if (len > wnd->extent_max)
 349                 wnd->extent_max = len;
 350
 351         rb_insert_start(&wnd->start_tree, e);
 352         rb_insert_count(&wnd->count_tree, e);
 353         wnd->count += 1;
 354
 355 out:;
 356 }
 357
 358 /*
 359  * wnd_remove_free_ext - Remove a run from the cached free space.
 360  */
 361 static void wnd_remove_free_ext(struct wnd_bitmap *wnd, size_t bit, size_t len)
 362 {
 363         struct rb_node *n, *n3;
 364         struct e_node *e, *e3;
 365         size_t end_in = bit + len;
 366         size_t end3, end, new_key, new_len, max_new_len;
 367
 368         /* Try to find extent before 'bit'. */
 369         n = rb_lookup(&wnd->start_tree, bit);
 370
 371         if (!n)
 372                 return;
 373
 374         e = rb_entry(n, struct e_node, start.node);
 375         end = e->start.key + e->count.key;
 376
 377         new_key = new_len = 0;
 378         len = e->count.key;
 379
 380         /* Range [bit,end_in) must be inside 'e' or outside 'e' and 'n'. */
 381         if (e->start.key > bit)
 382                 ;
 383         else if (end_in <= end) {
 384                 /* Range [bit,end_in) inside 'e'. */
 385                 new_key = end_in;
 386                 new_len = end - end_in;
 387                 len = bit - e->start.key;
 388         } else if (bit > end) {
 389                 bool bmax = false;
 390
 391                 n3 = rb_next(n);
 392
 393                 while (n3) {
 394                         e3 = rb_entry(n3, struct e_node, start.node);
 395                         if (e3->start.key >= end_in)
 396                                 break;
 397
 398                         if (e3->count.key == wnd->extent_max)
 399                                 bmax = true;
 400
 401                         end3 = e3->start.key + e3->count.key;
 402                         if (end3 > end_in) {
 403                                 e3->start.key = end_in;
 404                                 rb_erase(&e3->count.node, &wnd->count_tree);
 405                                 e3->count.key = end3 - end_in;
 406                                 rb_insert_count(&wnd->count_tree, e3);
 407                                 break;
 408                         }
 409
 410                         n3 = rb_next(n3);
 411                         rb_erase(&e3->start.node, &wnd->start_tree);
 412                         rb_erase(&e3->count.node, &wnd->count_tree);
 413                         wnd->count -= 1;
 414                         kmem_cache_free(ntfs_enode_cachep, e3);
 415                 }
 416                 if (!bmax)
 417                         return;
 418                 n3 = rb_first(&wnd->count_tree);
 419                 wnd->extent_max =
 420                         n3 ? rb_entry(n3, struct e_node, count.node)->count.key
 421                            : 0;
 422                 return;
 423         }
 424
 425         if (e->count.key != wnd->extent_max) {
 426                 ;
 427         } else if (rb_prev(&e->count.node)) {
 428                 ;
 429         } else {
 430                 n3 = rb_next(&e->count.node);
 431                 max_new_len = max(len, new_len);
 432                 if (!n3) {
 433                         wnd->extent_max = max_new_len;
 434                 } else {
 435                         e3 = rb_entry(n3, struct e_node, count.node);
 436                         wnd->extent_max = max(e3->count.key, max_new_len);
 437                 }
 438         }
 439
 440         if (!len) {
 441                 if (new_len) {
 442                         e->start.key = new_key;
 443                         rb_erase(&e->count.node, &wnd->count_tree);
 444                         e->count.key = new_len;
 445                         rb_insert_count(&wnd->count_tree, e);
 446                 } else {
 447                         rb_erase(&e->start.node, &wnd->start_tree);
 448                         rb_erase(&e->count.node, &wnd->count_tree);
 449                         wnd->count -= 1;
 450                         kmem_cache_free(ntfs_enode_cachep, e);
 451                 }
 452                 goto out;
 453         }
 454         rb_erase(&e->count.node, &wnd->count_tree);
 455         e->count.key = len;
 456         rb_insert_count(&wnd->count_tree, e);
 457
 458         if (!new_len)
 459                 goto out;
 460
 461         if (wnd->count >= NTFS_MAX_WND_EXTENTS) {
 462                 wnd->uptodated = -1;
 463
 464                 /* Get minimal extent. */
 465                 e = rb_entry(rb_last(&wnd->count_tree), struct e_node,
 466                              count.node);
 467                 if (e->count.key > new_len)
 468                         goto out;
 469
 470                 /* Replace minimum. */
 471                 rb_erase(&e->start.node, &wnd->start_tree);
 472                 rb_erase(&e->count.node, &wnd->count_tree);
 473                 wnd->count -= 1;
 474         } else {
 475                 e = kmem_cache_alloc(ntfs_enode_cachep, GFP_ATOMIC);
 476                 if (!e)
 477                         wnd->uptodated = -1;
 478         }
 479
 480         if (e) {
 481                 e->start.key = new_key;
 482                 e->count.key = new_len;
 483                 rb_insert_start(&wnd->start_tree, e);
 484                 rb_insert_count(&wnd->count_tree, e);
 485                 wnd->count += 1;
 486         }
 487
 488 out:
 489         if (!wnd->count && 1 != wnd->uptodated)
 490                 wnd_rescan(wnd);
 491 }
 492
 493 /*
 494  * wnd_rescan - Scan all bitmap. Used while initialization.
 495  */
 496 static int wnd_rescan(struct wnd_bitmap *wnd)
 497 {
 498         int err = 0;
 499         size_t prev_tail = 0;
 500         struct super_block *sb = wnd->sb;
 501         struct ntfs_sb_info *sbi = sb->s_fs_info;
 502         u64 lbo, len = 0;
 503         u32 blocksize = sb->s_blocksize;
 504         u8 cluster_bits = sbi->cluster_bits;
 505         u32 wbits = 8 * sb->s_blocksize;
 506         u32 used, frb;
 507         size_t wpos, wbit, iw, vbo;
 508         struct buffer_head *bh = NULL;
 509         CLST lcn, clen;
 510
 511         wnd->uptodated = 0;
 512         wnd->extent_max = 0;
 513         wnd->extent_min = MINUS_ONE_T;
 514         wnd->total_zeroes = 0;
 515
 516         vbo = 0;
 517
 518         for (iw = 0; iw < wnd->nwnd; iw++) {
 519                 if (iw + 1 == wnd->nwnd)
 520                         wbits = wnd->bits_last;
 521
 522                 if (wnd->inited) {
 523                         if (!wnd->free_bits[iw]) {
 524                                 /* All ones. */
 525                                 if (prev_tail) {
 526                                         wnd_add_free_ext(wnd,
 527                                                          vbo * 8 - prev_tail,
 528                                                          prev_tail, true);
 529                                         prev_tail = 0;
 530                                 }
 531                                 goto next_wnd;
 532                         }
 533                         if (wbits == wnd->free_bits[iw]) {
 534                                 /* All zeroes. */
 535                                 prev_tail += wbits;
 536                                 wnd->total_zeroes += wbits;
 537                                 goto next_wnd;
 538                         }
 539                 }
 540
 541                 if (!len) {
 542                         u32 off = vbo & sbi->cluster_mask;
 543
 544                         if (!run_lookup_entry(&wnd->run, vbo >> cluster_bits,
 545                                               &lcn, &clen, NULL)) {
 546                                 err = -ENOENT;
 547                                 goto out;
 548                         }
 549
 550                         lbo = ((u64)lcn << cluster_bits) + off;
 551                         len = ((u64)clen << cluster_bits) - off;
 552                 }
 553
 554                 bh = ntfs_bread(sb, lbo >> sb->s_blocksize_bits);
 555                 if (!bh) {
 556                         err = -EIO;
 557                         goto out;
 558                 }
 559
 560                 used = ntfs_bitmap_weight_le(bh->b_data, wbits);
 561                 if (used < wbits) {
 562                         frb = wbits - used;
 563                         wnd->free_bits[iw] = frb;
 564                         wnd->total_zeroes += frb;
 565                 }
 566
 567                 wpos = 0;
 568                 wbit = vbo * 8;
 569
 570                 if (wbit + wbits > wnd->nbits)
 571                         wbits = wnd->nbits - wbit;
 572
 573                 do {
 574                         used = find_next_zero_bit_le(bh->b_data, wbits, wpos);
 575
 576                         if (used > wpos && prev_tail) {
 577                                 wnd_add_free_ext(wnd, wbit + wpos - prev_tail,
 578                                                  prev_tail, true);
 579                                 prev_tail = 0;
 580                         }
 581
 582                         wpos = used;
 583
 584                         if (wpos >= wbits) {
 585                                 /* No free blocks. */
 586                                 prev_tail = 0;
 587                                 break;
 588                         }
 589
 590                         frb = find_next_bit_le(bh->b_data, wbits, wpos);
 591                         if (frb >= wbits) {
 592                                 /* Keep last free block. */
 593                                 prev_tail += frb - wpos;
 594                                 break;
 595                         }
 596
 597                         wnd_add_free_ext(wnd, wbit + wpos - prev_tail,
 598                                          frb + prev_tail - wpos, true);
 599
 600                         /* Skip free block and first '1'. */
 601                         wpos = frb + 1;
 602                         /* Reset previous tail. */
 603                         prev_tail = 0;
 604                 } while (wpos < wbits);
 605
 606 next_wnd:
 607
 608                 if (bh)
 609                         put_bh(bh);
 610                 bh = NULL;
 611
 612                 vbo += blocksize;
 613                 if (len) {
 614                         len -= blocksize;
 615                         lbo += blocksize;
 616                 }
 617         }
 618
 619         /* Add last block. */
 620         if (prev_tail)
 621                 wnd_add_free_ext(wnd, wnd->nbits - prev_tail, prev_tail, true);
 622
 623         /*
 624          * Before init cycle wnd->uptodated was 0.
 625          * If any errors or limits occurs while initialization then
 626          * wnd->uptodated will be -1.
 627          * If 'uptodated' is still 0 then Tree is really updated.
 628          */
 629         if (!wnd->uptodated)
 630                 wnd->uptodated = 1;
 631
 632         if (wnd->zone_bit != wnd->zone_end) {
 633                 size_t zlen = wnd->zone_end - wnd->zone_bit;
 634
 635                 wnd->zone_end = wnd->zone_bit;
 636                 wnd_zone_set(wnd, wnd->zone_bit, zlen);
 637         }
 638
 639 out:
 640         return err;
 641 }
 642
 643 int wnd_init(struct wnd_bitmap *wnd, struct super_block *sb, size_t nbits)
 644 {
 645         int err;
 646         u32 blocksize = sb->s_blocksize;
 647         u32 wbits = blocksize * 8;
 648
 649         init_rwsem(&wnd->rw_lock);
 650
 651         wnd->sb = sb;
 652         wnd->nbits = nbits;
 653         wnd->total_zeroes = nbits;
 654         wnd->extent_max = MINUS_ONE_T;
 655         wnd->zone_bit = wnd->zone_end = 0;
 656         wnd->nwnd = bytes_to_block(sb, bitmap_size(nbits));
 657         wnd->bits_last = nbits & (wbits - 1);
 658         if (!wnd->bits_last)
 659                 wnd->bits_last = wbits;
 660
 661         wnd->free_bits = kcalloc(wnd->nwnd, sizeof(u16), GFP_NOFS | __GFP_NOWARN);
 662         if (!wnd->free_bits)
 663                 return -ENOMEM;
 664
 665         err = wnd_rescan(wnd);
 666         if (err)
 667                 return err;
 668
 669         wnd->inited = true;
 670
 671         return 0;
 672 }
 673
 674 /*
 675  * wnd_map - Call sb_bread for requested window.
 676  */
 677 static struct buffer_head *wnd_map(struct wnd_bitmap *wnd, size_t iw)
 678 {
 679         size_t vbo;
 680         CLST lcn, clen;
 681         struct super_block *sb = wnd->sb;
 682         struct ntfs_sb_info *sbi;
 683         struct buffer_head *bh;
 684         u64 lbo;
 685
 686         sbi = sb->s_fs_info;
 687         vbo = (u64)iw << sb->s_blocksize_bits;
 688
 689         if (!run_lookup_entry(&wnd->run, vbo >> sbi->cluster_bits, &lcn, &clen,
 690                               NULL)) {
 691                 return ERR_PTR(-ENOENT);
 692         }
 693
 694         lbo = ((u64)lcn << sbi->cluster_bits) + (vbo & sbi->cluster_mask);
 695
 696         bh = ntfs_bread(wnd->sb, lbo >> sb->s_blocksize_bits);
 697         if (!bh)
 698                 return ERR_PTR(-EIO);
 699
 700         return bh;
 701 }
 702
 703 /*
 704  * wnd_set_free - Mark the bits range from bit to bit + bits as free.
 705  */
 706 int wnd_set_free(struct wnd_bitmap *wnd, size_t bit, size_t bits)
 707 {
 708         int err = 0;
 709         struct super_block *sb = wnd->sb;
 710         size_t bits0 = bits;
 711         u32 wbits = 8 * sb->s_blocksize;
 712         size_t iw = bit >> (sb->s_blocksize_bits + 3);
 713         u32 wbit = bit & (wbits - 1);
 714         struct buffer_head *bh;
 715
 716         while (iw < wnd->nwnd && bits) {
 717                 u32 tail, op;
 718
 719                 if (iw + 1 == wnd->nwnd)
 720                         wbits = wnd->bits_last;
 721
 722                 tail = wbits - wbit;
 723                 op = min_t(u32, tail, bits);
 724
 725                 bh = wnd_map(wnd, iw);
 726                 if (IS_ERR(bh)) {
 727                         err = PTR_ERR(bh);
 728                         break;
 729                 }
 730
 731                 lock_buffer(bh);
 732
 733                 ntfs_bitmap_clear_le(bh->b_data, wbit, op);
 734
 735                 wnd->free_bits[iw] += op;
 736
 737                 set_buffer_uptodate(bh);
 738                 mark_buffer_dirty(bh);
 739                 unlock_buffer(bh);
 740                 put_bh(bh);
 741
 742                 wnd->total_zeroes += op;
 743                 bits -= op;
 744                 wbit = 0;
 745                 iw += 1;
 746         }
 747
 748         wnd_add_free_ext(wnd, bit, bits0, false);
 749
 750         return err;
 751 }
 752
 753 /*
 754  * wnd_set_used - Mark the bits range from bit to bit + bits as used.
 755  */
 756 int wnd_set_used(struct wnd_bitmap *wnd, size_t bit, size_t bits)
 757 {
 758         int err = 0;
 759         struct super_block *sb = wnd->sb;
 760         size_t bits0 = bits;
 761         size_t iw = bit >> (sb->s_blocksize_bits + 3);
 762         u32 wbits = 8 * sb->s_blocksize;
 763         u32 wbit = bit & (wbits - 1);
 764         struct buffer_head *bh;
 765
 766         while (iw < wnd->nwnd && bits) {
 767                 u32 tail, op;
 768
 769                 if (unlikely(iw + 1 == wnd->nwnd))
 770                         wbits = wnd->bits_last;
 771
 772                 tail = wbits - wbit;
 773                 op = min_t(u32, tail, bits);
 774
 775                 bh = wnd_map(wnd, iw);
 776                 if (IS_ERR(bh)) {
 777                         err = PTR_ERR(bh);
 778                         break;
 779                 }
 780
 781                 lock_buffer(bh);
 782
 783                 ntfs_bitmap_set_le(bh->b_data, wbit, op);
 784                 wnd->free_bits[iw] -= op;
 785
 786                 set_buffer_uptodate(bh);
 787                 mark_buffer_dirty(bh);
 788                 unlock_buffer(bh);
 789                 put_bh(bh);
 790
 791                 wnd->total_zeroes -= op;
 792                 bits -= op;
 793                 wbit = 0;
 794                 iw += 1;
 795         }
 796
 797         if (!RB_EMPTY_ROOT(&wnd->start_tree))
 798                 wnd_remove_free_ext(wnd, bit, bits0);
 799
 800         return err;
 801 }
 802
 803 /*
 804  * wnd_set_used_safe - Mark the bits range from bit to bit + bits as used.
 805  *
 806  * Unlikely wnd_set_used/wnd_set_free this function is not full trusted.
 807  * It scans every bit in bitmap and marks free bit as used.
 808  * @done - how many bits were marked as used.
 809  *
 810  * NOTE: normally *done should be 0.
 811  */
 812 int wnd_set_used_safe(struct wnd_bitmap *wnd, size_t bit, size_t bits,
 813                       size_t *done)
 814 {
 815         size_t i, from = 0, len = 0;
 816         int err = 0;
 817
 818         *done = 0;
 819         for (i = 0; i < bits; i++) {
 820                 if (wnd_is_free(wnd, bit + i, 1)) {
 821                         if (!len)
 822                                 from = bit + i;
 823                         len += 1;
 824                 } else if (len) {
 825                         err = wnd_set_used(wnd, from, len);
 826                         *done += len;
 827                         len = 0;
 828                         if (err)
 829                                 break;
 830                 }
 831         }
 832
 833         if (len) {
 834                 /* last fragment. */
 835                 err = wnd_set_used(wnd, from, len);
 836                 *done += len;
 837         }
 838         return err;
 839 }
 840
 841 /*
 842  * wnd_is_free_hlp
 843  *
 844  * Return: True if all clusters [bit, bit+bits) are free (bitmap only).
 845  */
 846 static bool wnd_is_free_hlp(struct wnd_bitmap *wnd, size_t bit, size_t bits)
 847 {
 848         struct super_block *sb = wnd->sb;
 849         size_t iw = bit >> (sb->s_blocksize_bits + 3);
 850         u32 wbits = 8 * sb->s_blocksize;
 851         u32 wbit = bit & (wbits - 1);
 852
 853         while (iw < wnd->nwnd && bits) {
 854                 u32 tail, op;
 855
 856                 if (unlikely(iw + 1 == wnd->nwnd))
 857                         wbits = wnd->bits_last;
 858
 859                 tail = wbits - wbit;
 860                 op = min_t(u32, tail, bits);
 861
 862                 if (wbits != wnd->free_bits[iw]) {
 863                         bool ret;
 864                         struct buffer_head *bh = wnd_map(wnd, iw);
 865
 866                         if (IS_ERR(bh))
 867                                 return false;
 868
 869                         ret = are_bits_clear(bh->b_data, wbit, op);
 870
 871                         put_bh(bh);
 872                         if (!ret)
 873                                 return false;
 874                 }
 875
 876                 bits -= op;
 877                 wbit = 0;
 878                 iw += 1;
 879         }
 880
 881         return true;
 882 }
 883
 884 /*
 885  * wnd_is_free
 886  *
 887  * Return: True if all clusters [bit, bit+bits) are free.
 888  */
 889 bool wnd_is_free(struct wnd_bitmap *wnd, size_t bit, size_t bits)
 890 {
 891         bool ret;
 892         struct rb_node *n;
 893         size_t end;
 894         struct e_node *e;
 895
 896         if (RB_EMPTY_ROOT(&wnd->start_tree))
 897                 goto use_wnd;
 898
 899         n = rb_lookup(&wnd->start_tree, bit);
 900         if (!n)
 901                 goto use_wnd;
 902
 903         e = rb_entry(n, struct e_node, start.node);
 904
 905         end = e->start.key + e->count.key;
 906
 907         if (bit < end && bit + bits <= end)
 908                 return true;
 909
 910 use_wnd:
 911         ret = wnd_is_free_hlp(wnd, bit, bits);
 912
 913         return ret;
 914 }
 915
 916 /*
 917  * wnd_is_used
 918  *
 919  * Return: True if all clusters [bit, bit+bits) are used.
 920  */
 921 bool wnd_is_used(struct wnd_bitmap *wnd, size_t bit, size_t bits)
 922 {
 923         bool ret = false;
 924         struct super_block *sb = wnd->sb;
 925         size_t iw = bit >> (sb->s_blocksize_bits + 3);
 926         u32 wbits = 8 * sb->s_blocksize;
 927         u32 wbit = bit & (wbits - 1);
 928         size_t end;
 929         struct rb_node *n;
 930         struct e_node *e;
 931
 932         if (RB_EMPTY_ROOT(&wnd->start_tree))
 933                 goto use_wnd;
 934
 935         end = bit + bits;
 936         n = rb_lookup(&wnd->start_tree, end - 1);
 937         if (!n)
 938                 goto use_wnd;
 939
 940         e = rb_entry(n, struct e_node, start.node);
 941         if (e->start.key + e->count.key > bit)
 942                 return false;
 943
 944 use_wnd:
 945         while (iw < wnd->nwnd && bits) {
 946                 u32 tail, op;
 947
 948                 if (unlikely(iw + 1 == wnd->nwnd))
 949                         wbits = wnd->bits_last;
 950
 951                 tail = wbits - wbit;
 952                 op = min_t(u32, tail, bits);
 953
 954                 if (wnd->free_bits[iw]) {
 955                         bool ret;
 956                         struct buffer_head *bh = wnd_map(wnd, iw);
 957
 958                         if (IS_ERR(bh))
 959                                 goto out;
 960
 961                         ret = are_bits_set(bh->b_data, wbit, op);
 962                         put_bh(bh);
 963                         if (!ret)
 964                                 goto out;
 965                 }
 966
 967                 bits -= op;
 968                 wbit = 0;
 969                 iw += 1;
 970         }
 971         ret = true;
 972
 973 out:
 974         return ret;
 975 }
 976
 977 /*
 978  * wnd_find - Look for free space.
 979  *
 980  * - flags - BITMAP_FIND_XXX flags
 981  *
 982  * Return: 0 if not found.
 983  */
 984 size_t wnd_find(struct wnd_bitmap *wnd, size_t to_alloc, size_t hint,
 985                 size_t flags, size_t *allocated)
 986 {
 987         struct super_block *sb;
 988         u32 wbits, wpos, wzbit, wzend;
 989         size_t fnd, max_alloc, b_len, b_pos;
 990         size_t iw, prev_tail, nwnd, wbit, ebit, zbit, zend;
 991         size_t to_alloc0 = to_alloc;
 992         const struct e_node *e;
 993         const struct rb_node *pr, *cr;
 994         u8 log2_bits;
 995         bool fbits_valid;
 996         struct buffer_head *bh;
 997
 998         /* Fast checking for available free space. */
 999         if (flags & BITMAP_FIND_FULL) {
1000                 size_t zeroes = wnd_zeroes(wnd);
1001
1002                 zeroes -= wnd->zone_end - wnd->zone_bit;
1003                 if (zeroes < to_alloc0)
1004                         goto no_space;
1005
1006                 if (to_alloc0 > wnd->extent_max)
1007                         goto no_space;
1008         } else {
1009                 if (to_alloc > wnd->extent_max)
1010                         to_alloc = wnd->extent_max;
1011         }
1012
1013         if (wnd->zone_bit <= hint && hint < wnd->zone_end)
1014                 hint = wnd->zone_end;
1015
1016         max_alloc = wnd->nbits;
1017         b_len = b_pos = 0;
1018
1019         if (hint >= max_alloc)
1020                 hint = 0;
1021
1022         if (RB_EMPTY_ROOT(&wnd->start_tree)) {
1023                 if (wnd->uptodated == 1) {
1024                         /* Extents tree is updated -> No free space. */
1025                         goto no_space;
1026                 }
1027                 goto scan_bitmap;
1028         }
1029
1030         e = NULL;
1031         if (!hint)
1032                 goto allocate_biggest;
1033
1034         /* Use hint: Enumerate extents by start >= hint. */
1035         pr = NULL;
1036         cr = wnd->start_tree.rb_node;
1037
1038         for (;;) {
1039                 e = rb_entry(cr, struct e_node, start.node);
1040
1041                 if (e->start.key == hint)
1042                         break;
1043
1044                 if (e->start.key < hint) {
1045                         pr = cr;
1046                         cr = cr->rb_right;
1047                         if (!cr)
1048                                 break;
1049                         continue;
1050                 }
1051
1052                 cr = cr->rb_left;
1053                 if (!cr) {
1054                         e = pr ? rb_entry(pr, struct e_node, start.node) : NULL;
1055                         break;
1056                 }
1057         }
1058
1059         if (!e)
1060                 goto allocate_biggest;
1061
1062         if (e->start.key + e->count.key > hint) {
1063                 /* We have found extension with 'hint' inside. */
1064                 size_t len = e->start.key + e->count.key - hint;
1065
1066                 if (len >= to_alloc && hint + to_alloc <= max_alloc) {
1067                         fnd = hint;
1068                         goto found;
1069                 }
1070
1071                 if (!(flags & BITMAP_FIND_FULL)) {
1072                         if (len > to_alloc)
1073                                 len = to_alloc;
1074
1075                         if (hint + len <= max_alloc) {
1076                                 fnd = hint;
1077                                 to_alloc = len;
1078                                 goto found;
1079                         }
1080                 }
1081         }
1082
1083 allocate_biggest:
1084         /* Allocate from biggest free extent. */
1085         e = rb_entry(rb_first(&wnd->count_tree), struct e_node, count.node);
1086         if (e->count.key != wnd->extent_max)
1087                 wnd->extent_max = e->count.key;
1088
1089         if (e->count.key < max_alloc) {
1090                 if (e->count.key >= to_alloc) {
1091                         ;
1092                 } else if (flags & BITMAP_FIND_FULL) {
1093                         if (e->count.key < to_alloc0) {
1094                                 /* Biggest free block is less then requested. */
1095                                 goto no_space;
1096                         }
1097                         to_alloc = e->count.key;
1098                 } else if (-1 != wnd->uptodated) {
1099                         to_alloc = e->count.key;
1100                 } else {
1101                         /* Check if we can use more bits. */
1102                         size_t op, max_check;
1103                         struct rb_root start_tree;
1104
1105                         memcpy(&start_tree, &wnd->start_tree,
1106                                sizeof(struct rb_root));
1107                         memset(&wnd->start_tree, 0, sizeof(struct rb_root));
1108
1109                         max_check = e->start.key + to_alloc;
1110                         if (max_check > max_alloc)
1111                                 max_check = max_alloc;
1112                         for (op = e->start.key + e->count.key; op < max_check;
1113                              op++) {
1114                                 if (!wnd_is_free(wnd, op, 1))
1115                                         break;
1116                         }
1117                         memcpy(&wnd->start_tree, &start_tree,
1118                                sizeof(struct rb_root));
1119                         to_alloc = op - e->start.key;
1120                 }
1121
1122                 /* Prepare to return. */
1123                 fnd = e->start.key;
1124                 if (e->start.key + to_alloc > max_alloc)
1125                         to_alloc = max_alloc - e->start.key;
1126                 goto found;
1127         }
1128
1129         if (wnd->uptodated == 1) {
1130                 /* Extents tree is updated -> no free space. */
1131                 goto no_space;
1132         }
1133
1134         b_len = e->count.key;
1135         b_pos = e->start.key;
1136
1137 scan_bitmap:
1138         sb = wnd->sb;
1139         log2_bits = sb->s_blocksize_bits + 3;
1140
1141         /* At most two ranges [hint, max_alloc) + [0, hint). */
1142 Again:
1143
1144         /* TODO: Optimize request for case nbits > wbits. */
1145         iw = hint >> log2_bits;
1146         wbits = sb->s_blocksize * 8;
1147         wpos = hint & (wbits - 1);
1148         prev_tail = 0;
1149         fbits_valid = true;
1150
1151         if (max_alloc == wnd->nbits) {
1152                 nwnd = wnd->nwnd;
1153         } else {
1154                 size_t t = max_alloc + wbits - 1;
1155
1156                 nwnd = likely(t > max_alloc) ? (t >> log2_bits) : wnd->nwnd;
1157         }
1158
1159         /* Enumerate all windows. */
1160         for (; iw < nwnd; iw++) {
1161                 wbit = iw << log2_bits;
1162
1163                 if (!wnd->free_bits[iw]) {
1164                         if (prev_tail > b_len) {
1165                                 b_pos = wbit - prev_tail;
1166                                 b_len = prev_tail;
1167                         }
1168
1169                         /* Skip full used window. */
1170                         prev_tail = 0;
1171                         wpos = 0;
1172                         continue;
1173                 }
1174
1175                 if (unlikely(iw + 1 == nwnd)) {
1176                         if (max_alloc == wnd->nbits) {
1177                                 wbits = wnd->bits_last;
1178                         } else {
1179                                 size_t t = max_alloc & (wbits - 1);
1180
1181                                 if (t) {
1182                                         wbits = t;
1183                                         fbits_valid = false;
1184                                 }
1185                         }
1186                 }
1187
1188                 if (wnd->zone_end > wnd->zone_bit) {
1189                         ebit = wbit + wbits;
1190                         zbit = max(wnd->zone_bit, wbit);
1191                         zend = min(wnd->zone_end, ebit);
1192
1193                         /* Here we have a window [wbit, ebit) and zone [zbit, zend). */
1194                         if (zend <= zbit) {
1195                                 /* Zone does not overlap window. */
1196                         } else {
1197                                 wzbit = zbit - wbit;
1198                                 wzend = zend - wbit;
1199
1200                                 /* Zone overlaps window. */
1201                                 if (wnd->free_bits[iw] == wzend - wzbit) {
1202                                         prev_tail = 0;
1203                                         wpos = 0;
1204                                         continue;
1205                                 }
1206
1207                                 /* Scan two ranges window: [wbit, zbit) and [zend, ebit). */
1208                                 bh = wnd_map(wnd, iw);
1209
1210                                 if (IS_ERR(bh)) {
1211                                         /* TODO: Error */
1212                                         prev_tail = 0;
1213                                         wpos = 0;
1214                                         continue;
1215                                 }
1216
1217                                 /* Scan range [wbit, zbit). */
1218                                 if (wpos < wzbit) {
1219                                         /* Scan range [wpos, zbit). */
1220                                         fnd = wnd_scan(bh->b_data, wbit, wpos,
1221                                                        wzbit, to_alloc,
1222                                                        &prev_tail, &b_pos,
1223                                                        &b_len);
1224                                         if (fnd != MINUS_ONE_T) {
1225                                                 put_bh(bh);
1226                                                 goto found;
1227                                         }
1228                                 }
1229
1230                                 prev_tail = 0;
1231
1232                                 /* Scan range [zend, ebit). */
1233                                 if (wzend < wbits) {
1234                                         fnd = wnd_scan(bh->b_data, wbit,
1235                                                        max(wzend, wpos), wbits,
1236                                                        to_alloc, &prev_tail,
1237                                                        &b_pos, &b_len);
1238                                         if (fnd != MINUS_ONE_T) {
1239                                                 put_bh(bh);
1240                                                 goto found;
1241                                         }
1242                                 }
1243
1244                                 wpos = 0;
1245                                 put_bh(bh);
1246                                 continue;
1247                         }
1248                 }
1249
1250                 /* Current window does not overlap zone. */
1251                 if (!wpos && fbits_valid && wnd->free_bits[iw] == wbits) {
1252                         /* Window is empty. */
1253                         if (prev_tail + wbits >= to_alloc) {
1254                                 fnd = wbit + wpos - prev_tail;
1255                                 goto found;
1256                         }
1257
1258                         /* Increase 'prev_tail' and process next window. */
1259                         prev_tail += wbits;
1260                         wpos = 0;
1261                         continue;
1262                 }
1263
1264                 /* Read window. */
1265                 bh = wnd_map(wnd, iw);
1266                 if (IS_ERR(bh)) {
1267                         // TODO: Error.
1268                         prev_tail = 0;
1269                         wpos = 0;
1270                         continue;
1271                 }
1272
1273                 /* Scan range [wpos, eBits). */
1274                 fnd = wnd_scan(bh->b_data, wbit, wpos, wbits, to_alloc,
1275                                &prev_tail, &b_pos, &b_len);
1276                 put_bh(bh);
1277                 if (fnd != MINUS_ONE_T)
1278                         goto found;
1279         }
1280
1281         if (b_len < prev_tail) {
1282                 /* The last fragment. */
1283                 b_len = prev_tail;
1284                 b_pos = max_alloc - prev_tail;
1285         }
1286
1287         if (hint) {
1288                 /*
1289                  * We have scanned range [hint max_alloc).
1290                  * Prepare to scan range [0 hint + to_alloc).
1291                  */
1292                 size_t nextmax = hint + to_alloc;
1293
1294                 if (likely(nextmax >= hint) && nextmax < max_alloc)
1295                         max_alloc = nextmax;
1296                 hint = 0;
1297                 goto Again;
1298         }
1299
1300         if (!b_len)
1301                 goto no_space;
1302
1303         wnd->extent_max = b_len;
1304
1305         if (flags & BITMAP_FIND_FULL)
1306                 goto no_space;
1307
1308         fnd = b_pos;
1309         to_alloc = b_len;
1310
1311 found:
1312         if (flags & BITMAP_FIND_MARK_AS_USED) {
1313                 /* TODO: Optimize remove extent (pass 'e'?). */
1314                 if (wnd_set_used(wnd, fnd, to_alloc))
1315                         goto no_space;
1316         } else if (wnd->extent_max != MINUS_ONE_T &&
1317                    to_alloc > wnd->extent_max) {
1318                 wnd->extent_max = to_alloc;
1319         }
1320
1321         *allocated = fnd;
1322         return to_alloc;
1323
1324 no_space:
1325         return 0;
1326 }
1327
1328 /*
1329  * wnd_extend - Extend bitmap ($MFT bitmap).
1330  */
1331 int wnd_extend(struct wnd_bitmap *wnd, size_t new_bits)
1332 {
1333         int err;
1334         struct super_block *sb = wnd->sb;
1335         struct ntfs_sb_info *sbi = sb->s_fs_info;
1336         u32 blocksize = sb->s_blocksize;
1337         u32 wbits = blocksize * 8;
1338         u32 b0, new_last;
1339         size_t bits, iw, new_wnd;
1340         size_t old_bits = wnd->nbits;
1341         u16 *new_free;
1342
1343         if (new_bits <= old_bits)
1344                 return -EINVAL;
1345
1346         /* Align to 8 byte boundary. */
1347         new_wnd = bytes_to_block(sb, bitmap_size(new_bits));
1348         new_last = new_bits & (wbits - 1);
1349         if (!new_last)
1350                 new_last = wbits;
1351
1352         if (new_wnd != wnd->nwnd) {
1353                 new_free = kmalloc_array(new_wnd, sizeof(u16), GFP_NOFS);
1354                 if (!new_free)
1355                         return -ENOMEM;
1356
1357                 memcpy(new_free, wnd->free_bits, wnd->nwnd * sizeof(short));
1358                 memset(new_free + wnd->nwnd, 0,
1359                        (new_wnd - wnd->nwnd) * sizeof(short));
1360                 kfree(wnd->free_bits);
1361                 wnd->free_bits = new_free;
1362         }
1363
1364         /* Zero bits [old_bits,new_bits). */
1365         bits = new_bits - old_bits;
1366         b0 = old_bits & (wbits - 1);
1367
1368         for (iw = old_bits >> (sb->s_blocksize_bits + 3); bits; iw += 1) {
1369                 u32 op;
1370                 size_t frb;
1371                 u64 vbo, lbo, bytes;
1372                 struct buffer_head *bh;
1373
1374                 if (iw + 1 == new_wnd)
1375                         wbits = new_last;
1376
1377                 op = b0 + bits > wbits ? wbits - b0 : bits;
1378                 vbo = (u64)iw * blocksize;
1379
1380                 err = ntfs_vbo_to_lbo(sbi, &wnd->run, vbo, &lbo, &bytes);
1381                 if (err)
1382                         break;
1383
1384                 bh = ntfs_bread(sb, lbo >> sb->s_blocksize_bits);
1385                 if (!bh)
1386                         return -EIO;
1387
1388                 lock_buffer(bh);
1389
1390                 ntfs_bitmap_clear_le(bh->b_data, b0, blocksize * 8 - b0);
1391                 frb = wbits - ntfs_bitmap_weight_le(bh->b_data, wbits);
1392                 wnd->total_zeroes += frb - wnd->free_bits[iw];
1393                 wnd->free_bits[iw] = frb;
1394
1395                 set_buffer_uptodate(bh);
1396                 mark_buffer_dirty(bh);
1397                 unlock_buffer(bh);
1398                 /* err = sync_dirty_buffer(bh); */
1399
1400                 b0 = 0;
1401                 bits -= op;
1402         }
1403
1404         wnd->nbits = new_bits;
1405         wnd->nwnd = new_wnd;
1406         wnd->bits_last = new_last;
1407
1408         wnd_add_free_ext(wnd, old_bits, new_bits - old_bits, false);
1409
1410         return 0;
1411 }
1412
1413 void wnd_zone_set(struct wnd_bitmap *wnd, size_t lcn, size_t len)
1414 {
1415         size_t zlen = wnd->zone_end - wnd->zone_bit;
1416
1417         if (zlen)
1418                 wnd_add_free_ext(wnd, wnd->zone_bit, zlen, false);
1419
1420         if (!RB_EMPTY_ROOT(&wnd->start_tree) && len)
1421                 wnd_remove_free_ext(wnd, lcn, len);
1422
1423         wnd->zone_bit = lcn;
1424         wnd->zone_end = lcn + len;
1425 }
1426
1427 int ntfs_trim_fs(struct ntfs_sb_info *sbi, struct fstrim_range *range)
1428 {
1429         int err = 0;
1430         struct super_block *sb = sbi->sb;
1431         struct wnd_bitmap *wnd = &sbi->used.bitmap;
1432         u32 wbits = 8 * sb->s_blocksize;
1433         CLST len = 0, lcn = 0, done = 0;
1434         CLST minlen = bytes_to_cluster(sbi, range->minlen);
1435         CLST lcn_from = bytes_to_cluster(sbi, range->start);
1436         size_t iw = lcn_from >> (sb->s_blocksize_bits + 3);
1437         u32 wbit = lcn_from & (wbits - 1);
1438         CLST lcn_to;
1439
1440         if (!minlen)
1441                 minlen = 1;
1442
1443         if (range->len == (u64)-1)
1444                 lcn_to = wnd->nbits;
1445         else
1446                 lcn_to = bytes_to_cluster(sbi, range->start + range->len);
1447
1448         down_read_nested(&wnd->rw_lock, BITMAP_MUTEX_CLUSTERS);
1449
1450         for (; iw < wnd->nwnd; iw++, wbit = 0) {
1451                 CLST lcn_wnd = iw * wbits;
1452                 struct buffer_head *bh;
1453
1454                 if (lcn_wnd > lcn_to)
1455                         break;
1456
1457                 if (!wnd->free_bits[iw])
1458                         continue;
1459
1460                 if (iw + 1 == wnd->nwnd)
1461                         wbits = wnd->bits_last;
1462
1463                 if (lcn_wnd + wbits > lcn_to)
1464                         wbits = lcn_to - lcn_wnd;
1465
1466                 bh = wnd_map(wnd, iw);
1467                 if (IS_ERR(bh)) {
1468                         err = PTR_ERR(bh);
1469                         break;
1470                 }
1471
1472                 for (; wbit < wbits; wbit++) {
1473                         if (!test_bit_le(wbit, bh->b_data)) {
1474                                 if (!len)
1475                                         lcn = lcn_wnd + wbit;
1476                                 len += 1;
1477                                 continue;
1478                         }
1479                         if (len >= minlen) {
1480                                 err = ntfs_discard(sbi, lcn, len);
1481                                 if (err)
1482                                         goto out;
1483                                 done += len;
1484                         }
1485                         len = 0;
1486                 }
1487                 put_bh(bh);
1488         }
1489
1490         /* Process the last fragment. */
1491         if (len >= minlen) {
1492                 err = ntfs_discard(sbi, lcn, len);
1493                 if (err)
1494                         goto out;
1495                 done += len;
1496         }
1497
1498 out:
1499         range->len = (u64)done << sbi->cluster_bits;
1500
1501         up_read(&wnd->rw_lock);
1502
1503         return err;
1504 }
1505
1506 #if BITS_PER_LONG == 64
1507 typedef __le64 bitmap_ulong;
1508 #define cpu_to_ul(x) cpu_to_le64(x)
1509 #define ul_to_cpu(x) le64_to_cpu(x)
1510 #else
1511 typedef __le32 bitmap_ulong;
1512 #define cpu_to_ul(x) cpu_to_le32(x)
1513 #define ul_to_cpu(x) le32_to_cpu(x)
1514 #endif
1515
1516 void ntfs_bitmap_set_le(void *map, unsigned int start, int len)
1517 {
1518         bitmap_ulong *p = (bitmap_ulong *)map + BIT_WORD(start);
1519         const unsigned int size = start + len;
1520         int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
1521         bitmap_ulong mask_to_set = cpu_to_ul(BITMAP_FIRST_WORD_MASK(start));
1522
1523         while (len - bits_to_set >= 0) {
1524                 *p |= mask_to_set;
1525                 len -= bits_to_set;
1526                 bits_to_set = BITS_PER_LONG;
1527                 mask_to_set = cpu_to_ul(~0UL);
1528                 p++;
1529         }
1530         if (len) {
1531                 mask_to_set &= cpu_to_ul(BITMAP_LAST_WORD_MASK(size));
1532                 *p |= mask_to_set;
1533         }
1534 }
1535
1536 void ntfs_bitmap_clear_le(void *map, unsigned int start, int len)
1537 {
1538         bitmap_ulong *p = (bitmap_ulong *)map + BIT_WORD(start);
1539         const unsigned int size = start + len;
1540         int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
1541         bitmap_ulong mask_to_clear = cpu_to_ul(BITMAP_FIRST_WORD_MASK(start));
1542
1543         while (len - bits_to_clear >= 0) {
1544                 *p &= ~mask_to_clear;
1545                 len -= bits_to_clear;
1546                 bits_to_clear = BITS_PER_LONG;
1547                 mask_to_clear = cpu_to_ul(~0UL);
1548                 p++;
1549         }
1550         if (len) {
1551                 mask_to_clear &= cpu_to_ul(BITMAP_LAST_WORD_MASK(size));
1552                 *p &= ~mask_to_clear;
1553         }
1554 }
1555
1556 unsigned int ntfs_bitmap_weight_le(const void *bitmap, int bits)
1557 {
1558         const ulong *bmp = bitmap;
1559         unsigned int k, lim = bits / BITS_PER_LONG;
1560         unsigned int w = 0;
1561
1562         for (k = 0; k < lim; k++)
1563                 w += hweight_long(bmp[k]);
1564
1565         if (bits % BITS_PER_LONG) {
1566                 w += hweight_long(ul_to_cpu(((bitmap_ulong *)bitmap)[k]) &
1567                                   BITMAP_LAST_WORD_MASK(bits));
1568         }
1569
1570         return w;
1571 }