lib/ext2fs/blkmap64_rb.c

   1 /*
   2  * blkmap64_rb.c --- Simple rb-tree implementation for bitmaps
   3  *
   4  * (C)2010 Red Hat, Inc., Lukas Czerner <lczerner@redhat.com>
   5  *
   6  * %Begin-Header%
   7  * This file may be redistributed under the terms of the GNU Public
   8  * License.
   9  * %End-Header%
  10  */
  11
  12 #include <stdio.h>
  13 #include <string.h>
  14 #if HAVE_UNISTD_H
  15 #include <unistd.h>
  16 #endif
  17 #include <fcntl.h>
  18 #include <time.h>
  19 #if HAVE_SYS_STAT_H
  20 #include <sys/stat.h>
  21 #endif
  22 #if HAVE_SYS_TYPES_H
  23 #include <sys/types.h>
  24 #endif
  25
  26 #include "ext2_fs.h"
  27 #include "ext2fsP.h"
  28 #include "bmap64.h"
  29 #include "rbtree.h"
  30
  31 #include <limits.h>
  32
  33 struct bmap_rb_extent {
  34         struct rb_node node;
  35         __u64 start;
  36         __u64 count;
  37 };
  38
  39 struct ext2fs_rb_private {
  40         struct rb_root root;
  41         struct bmap_rb_extent *wcursor;
  42         struct bmap_rb_extent *rcursor;
  43         struct bmap_rb_extent *rcursor_next;
  44 #ifdef ENABLE_BMAP_STATS_OPS
  45         __u64 mark_hit;
  46         __u64 test_hit;
  47 #endif
  48 };
  49
  50 inline static struct bmap_rb_extent *node_to_extent(struct rb_node *node)
  51 {
  52         /*
  53          * This depends on the fact the struct rb_node is at the
  54          * beginning of the bmap_rb_extent structure.  We use this
  55          * instead of the ext2fs_rb_entry macro because it causes gcc
  56          * -Wall to generate a huge amount of noise.
  57          */
  58         return (struct bmap_rb_extent *) node;
  59 }
  60
  61 static int rb_insert_extent(__u64 start, __u64 count,
  62                             struct ext2fs_rb_private *);
  63 static void rb_get_new_extent(struct bmap_rb_extent **, __u64, __u64);
  64
  65 /* #define DEBUG_RB */
  66
  67 #ifdef DEBUG_RB
  68 static void print_tree(struct rb_root *root)
  69 {
  70         struct rb_node *node = NULL;
  71         struct bmap_rb_extent *ext;
  72
  73         printf("\t\t\t=================================\n");
  74         node = ext2fs_rb_first(root);
  75         for (node = ext2fs_rb_first(root); node != NULL;
  76              node = ext2fs_rb_next(node)) {
  77                 ext = node_to_extent(node);
  78                 printf("\t\t\t--> (%llu -> %llu)\n",
  79                         ext->start, ext->start + ext->count);
  80         }
  81         printf("\t\t\t=================================\n");
  82 }
  83
  84 static void check_tree(struct rb_root *root, const char *msg)
  85 {
  86         struct rb_node *node;
  87         struct bmap_rb_extent *ext, *old = NULL;
  88
  89         for (node = ext2fs_rb_first(root); node;
  90              node = ext2fs_rb_next(node)) {
  91                 ext = node_to_extent(node);
  92                 if (ext->count == 0) {
  93                         printf("Tree Error: count is zero\n");
  94                         printf("extent: %llu -> %llu (%llu)\n", ext->start,
  95                                 ext->start + ext->count, ext->count);
  96                         goto err_out;
  97                 }
  98                 if (ext->start + ext->count < ext->start) {
  99                         printf("Tree Error: start or count is crazy\n");
 100                         printf("extent: %llu -> %llu (%llu)\n", ext->start,
 101                                 ext->start + ext->count, ext->count);
 102                         goto err_out;
 103                 }
 104
 105                 if (old) {
 106                         if (old->start > ext->start) {
 107                                 printf("Tree Error: start is crazy\n");
 108                                 printf("extent: %llu -> %llu (%llu)\n",
 109                                         old->start, old->start + old->count,
 110                                         old->count);
 111                                 printf("extent next: %llu -> %llu (%llu)\n",
 112                                         ext->start, ext->start + ext->count,
 113                                         ext->count);
 114                                 goto err_out;
 115                         }
 116                         if ((old->start + old->count) >= ext->start) {
 117                                 printf("Tree Error: extent is crazy\n");
 118                                 printf("extent: %llu -> %llu (%llu)\n",
 119                                         old->start, old->start + old->count,
 120                                         old->count);
 121                                 printf("extent next: %llu -> %llu (%llu)\n",
 122                                         ext->start, ext->start + ext->count,
 123                                         ext->count);
 124                                 goto err_out;
 125                         }
 126                 }
 127                 old = ext;
 128         }
 129         return;
 130
 131 err_out:
 132         printf("%s\n", msg);
 133         print_tree(root);
 134         exit(1);
 135 }
 136 #else
 137 #define check_tree(root, msg) do {} while (0)
 138 #define print_tree(root) do {} while (0)
 139 #endif
 140
 141 static void rb_get_new_extent(struct bmap_rb_extent **ext, __u64 start,
 142                              __u64 count)
 143 {
 144         struct bmap_rb_extent *new_ext;
 145         int retval;
 146
 147         retval = ext2fs_get_mem(sizeof (struct bmap_rb_extent),
 148                                 &new_ext);
 149         if (retval)
 150                 abort();
 151
 152         new_ext->start = start;
 153         new_ext->count = count;
 154         *ext = new_ext;
 155 }
 156
 157 inline
 158 static void rb_free_extent(struct ext2fs_rb_private *bp,
 159                            struct bmap_rb_extent *ext)
 160 {
 161         if (bp->wcursor == ext)
 162                 bp->wcursor = NULL;
 163         if (bp->rcursor == ext)
 164                 bp->rcursor = NULL;
 165         if (bp->rcursor_next == ext)
 166                 bp->rcursor_next = NULL;
 167         ext2fs_free_mem(&ext);
 168 }
 169
 170 static errcode_t rb_alloc_private_data (ext2fs_generic_bitmap bitmap)
 171 {
 172         struct ext2fs_rb_private *bp;
 173         errcode_t       retval;
 174
 175         retval = ext2fs_get_mem(sizeof (struct ext2fs_rb_private), &bp);
 176         if (retval)
 177                 return retval;
 178
 179         bp->root = RB_ROOT;
 180         bp->rcursor = NULL;
 181         bp->rcursor_next = NULL;
 182         bp->wcursor = NULL;
 183
 184 #ifdef ENABLE_BMAP_STATS_OPS
 185         bp->test_hit = 0;
 186         bp->mark_hit = 0;
 187 #endif
 188
 189         bitmap->private = (void *) bp;
 190         return 0;
 191 }
 192
 193 static errcode_t rb_new_bmap(ext2_filsys fs EXT2FS_ATTR((unused)),
 194                              ext2fs_generic_bitmap bitmap)
 195 {
 196         errcode_t       retval;
 197
 198         retval = rb_alloc_private_data (bitmap);
 199         if (retval)
 200                 return retval;
 201
 202         return 0;
 203 }
 204
 205 static void rb_free_tree(struct rb_root *root)
 206 {
 207         struct bmap_rb_extent *ext;
 208         struct rb_node *node, *next;
 209
 210         for (node = ext2fs_rb_first(root); node; node = next) {
 211                 next = ext2fs_rb_next(node);
 212                 ext = node_to_extent(node);
 213                 ext2fs_rb_erase(node, root);
 214                 ext2fs_free_mem(&ext);
 215         }
 216 }
 217
 218 static void rb_free_bmap(ext2fs_generic_bitmap bitmap)
 219 {
 220         struct ext2fs_rb_private *bp;
 221
 222         bp = (struct ext2fs_rb_private *) bitmap->private;
 223
 224         rb_free_tree(&bp->root);
 225         ext2fs_free_mem(&bp);
 226         bp = 0;
 227 }
 228
 229 static errcode_t rb_copy_bmap(ext2fs_generic_bitmap src,
 230                               ext2fs_generic_bitmap dest)
 231 {
 232         struct ext2fs_rb_private *src_bp, *dest_bp;
 233         struct bmap_rb_extent *src_ext, *dest_ext;
 234         struct rb_node *dest_node, *src_node, *dest_last, **n;
 235         errcode_t retval = 0;
 236
 237         retval = rb_alloc_private_data (dest);
 238         if (retval)
 239                 return retval;
 240
 241         src_bp = (struct ext2fs_rb_private *) src->private;
 242         dest_bp = (struct ext2fs_rb_private *) dest->private;
 243         src_bp->rcursor = NULL;
 244         dest_bp->rcursor = NULL;
 245
 246         src_node = ext2fs_rb_first(&src_bp->root);
 247         while (src_node) {
 248                 src_ext = node_to_extent(src_node);
 249                 retval = ext2fs_get_mem(sizeof (struct bmap_rb_extent),
 250                                         &dest_ext);
 251                 if (retval)
 252                         break;
 253
 254                 memcpy(dest_ext, src_ext, sizeof(struct bmap_rb_extent));
 255
 256                 dest_node = &dest_ext->node;
 257                 n = &dest_bp->root.rb_node;
 258
 259                 dest_last = NULL;
 260                 if (*n) {
 261                         dest_last = ext2fs_rb_last(&dest_bp->root);
 262                         n = &(dest_last)->rb_right;
 263                 }
 264
 265                 ext2fs_rb_link_node(dest_node, dest_last, n);
 266                 ext2fs_rb_insert_color(dest_node, &dest_bp->root);
 267
 268                 src_node = ext2fs_rb_next(src_node);
 269         }
 270
 271         return retval;
 272 }
 273
 274 static void rb_truncate(__u64 new_max, struct rb_root *root)
 275 {
 276         struct bmap_rb_extent *ext;
 277         struct rb_node *node;
 278
 279         node = ext2fs_rb_last(root);
 280         while (node) {
 281                 ext = node_to_extent(node);
 282
 283                 if ((ext->start + ext->count - 1) <= new_max)
 284                         break;
 285                 else if (ext->start > new_max) {
 286                         ext2fs_rb_erase(node, root);
 287                         ext2fs_free_mem(&ext);
 288                         node = ext2fs_rb_last(root);
 289                         continue;
 290                 } else
 291                         ext->count = new_max - ext->start + 1;
 292         }
 293 }
 294
 295 static errcode_t rb_resize_bmap(ext2fs_generic_bitmap bmap,
 296                                 __u64 new_end, __u64 new_real_end)
 297 {
 298         struct ext2fs_rb_private *bp;
 299
 300         bp = (struct ext2fs_rb_private *) bmap->private;
 301         bp->rcursor = NULL;
 302         bp->wcursor = NULL;
 303
 304         rb_truncate(((new_end < bmap->end) ? new_end : bmap->end) - bmap->start,
 305                     &bp->root);
 306
 307         bmap->end = new_end;
 308         bmap->real_end = new_real_end;
 309
 310         if (bmap->end < bmap->real_end)
 311                 rb_insert_extent(bmap->end + 1 - bmap->start,
 312                                  bmap->real_end - bmap->end, bp);
 313         return 0;
 314
 315 }
 316
 317 inline static int
 318 rb_test_bit(struct ext2fs_rb_private *bp, __u64 bit)
 319 {
 320         struct bmap_rb_extent *rcursor, *next_ext = NULL;
 321         struct rb_node *parent = NULL, *next;
 322         struct rb_node **n = &bp->root.rb_node;
 323         struct bmap_rb_extent *ext;
 324
 325         rcursor = bp->rcursor;
 326         if (!rcursor)
 327                 goto search_tree;
 328
 329         if (bit >= rcursor->start && bit < rcursor->start + rcursor->count) {
 330 #ifdef ENABLE_BMAP_STATS_OPS
 331                 bp->test_hit++;
 332 #endif
 333                 return 1;
 334         }
 335
 336         next_ext = bp->rcursor_next;
 337         if (!next_ext) {
 338                 next = ext2fs_rb_next(&rcursor->node);
 339                 if (next)
 340                         next_ext = node_to_extent(next);
 341                 bp->rcursor_next = next_ext;
 342         }
 343         if (next_ext) {
 344                 if ((bit >= rcursor->start + rcursor->count) &&
 345                     (bit < next_ext->start)) {
 346 #ifdef BMAP_STATS_OPS
 347                         bp->test_hit++;
 348 #endif
 349                         return 0;
 350                 }
 351         }
 352         bp->rcursor = NULL;
 353         bp->rcursor_next = NULL;
 354
 355         rcursor = bp->wcursor;
 356         if (!rcursor)
 357                 goto search_tree;
 358
 359         if (bit >= rcursor->start && bit < rcursor->start + rcursor->count)
 360                 return 1;
 361
 362 search_tree:
 363
 364         while (*n) {
 365                 parent = *n;
 366                 ext = node_to_extent(parent);
 367                 if (bit < ext->start)
 368                         n = &(*n)->rb_left;
 369                 else if (bit >= (ext->start + ext->count))
 370                         n = &(*n)->rb_right;
 371                 else {
 372                         bp->rcursor = ext;
 373                         bp->rcursor_next = NULL;
 374                         return 1;
 375                 }
 376         }
 377         return 0;
 378 }
 379
 380 static int rb_insert_extent(__u64 start, __u64 count,
 381                             struct ext2fs_rb_private *bp)
 382 {
 383         struct rb_root *root = &bp->root;
 384         struct rb_node *parent = NULL, **n = &root->rb_node;
 385         struct rb_node *new_node, *node, *next;
 386         struct bmap_rb_extent *new_ext;
 387         struct bmap_rb_extent *ext;
 388         int retval = 0;
 389
 390         bp->rcursor_next = NULL;
 391         ext = bp->wcursor;
 392         if (ext) {
 393                 if (start >= ext->start &&
 394                     start <= (ext->start + ext->count)) {
 395 #ifdef ENABLE_BMAP_STATS_OPS
 396                         bp->mark_hit++;
 397 #endif
 398                         goto got_extent;
 399                 }
 400         }
 401
 402         while (*n) {
 403                 parent = *n;
 404                 ext = node_to_extent(parent);
 405
 406                 if (start < ext->start) {
 407                         n = &(*n)->rb_left;
 408                 } else if (start > (ext->start + ext->count)) {
 409                         n = &(*n)->rb_right;
 410                 } else {
 411 got_extent:
 412                         if ((start + count) <= (ext->start + ext->count))
 413                                 return 1;
 414
 415                         if ((ext->start + ext->count) == start)
 416                                 retval = 0;
 417                         else
 418                                 retval = 1;
 419
 420                         count += (start - ext->start);
 421                         start = ext->start;
 422                         new_ext = ext;
 423                         new_node = &ext->node;
 424
 425                         goto skip_insert;
 426                 }
 427         }
 428
 429         rb_get_new_extent(&new_ext, start, count);
 430
 431         new_node = &new_ext->node;
 432         ext2fs_rb_link_node(new_node, parent, n);
 433         ext2fs_rb_insert_color(new_node, root);
 434         bp->wcursor = new_ext;
 435
 436         node = ext2fs_rb_prev(new_node);
 437         if (node) {
 438                 ext = node_to_extent(node);
 439                 if ((ext->start + ext->count) == start) {
 440                         start = ext->start;
 441                         count += ext->count;
 442                         ext2fs_rb_erase(node, root);
 443                         rb_free_extent(bp, ext);
 444                 }
 445         }
 446
 447 skip_insert:
 448         /* See if we can merge extent to the right */
 449         for (node = ext2fs_rb_next(new_node); node != NULL; node = next) {
 450                 next = ext2fs_rb_next(node);
 451                 ext = node_to_extent(node);
 452
 453                 if ((ext->start + ext->count) <= start)
 454                         continue;
 455
 456                 /* No more merging */
 457                 if ((start + count) < ext->start)
 458                         break;
 459
 460                 /* ext is embedded in new_ext interval */
 461                 if ((start + count) >= (ext->start + ext->count)) {
 462                         ext2fs_rb_erase(node, root);
 463                         rb_free_extent(bp, ext);
 464                         continue;
 465                 } else {
 466                 /* merge ext with new_ext */
 467                         count += ((ext->start + ext->count) -
 468                                   (start + count));
 469                         ext2fs_rb_erase(node, root);
 470                         rb_free_extent(bp, ext);
 471                         break;
 472                 }
 473         }
 474
 475         new_ext->start = start;
 476         new_ext->count = count;
 477
 478         return retval;
 479 }
 480
 481 static int rb_remove_extent(__u64 start, __u64 count,
 482                             struct ext2fs_rb_private *bp)
 483 {
 484         struct rb_root *root = &bp->root;
 485         struct rb_node *parent = NULL, **n = &root->rb_node;
 486         struct rb_node *node;
 487         struct bmap_rb_extent *ext;
 488         __u64 new_start, new_count;
 489         int retval = 0;
 490
 491         if (EXT2FS_RB_EMPTY_ROOT(root))
 492                 return 0;
 493
 494         while (*n) {
 495                 parent = *n;
 496                 ext = node_to_extent(parent);
 497                 if (start < ext->start) {
 498                         n = &(*n)->rb_left;
 499                         continue;
 500                 } else if (start >= (ext->start + ext->count)) {
 501                         n = &(*n)->rb_right;
 502                         continue;
 503                 }
 504
 505                 if ((start > ext->start) &&
 506                     (start + count) < (ext->start + ext->count)) {
 507                         /* We have to split extent into two */
 508                         new_start = start + count;
 509                         new_count = (ext->start + ext->count) - new_start;
 510
 511                         ext->count = start - ext->start;
 512
 513                         rb_insert_extent(new_start, new_count, bp);
 514                         return 1;
 515                 }
 516
 517                 if ((start + count) >= (ext->start + ext->count)) {
 518                         ext->count = start - ext->start;
 519                         retval = 1;
 520                 }
 521
 522                 if (0 == ext->count) {
 523                         parent = ext2fs_rb_next(&ext->node);
 524                         ext2fs_rb_erase(&ext->node, root);
 525                         rb_free_extent(bp, ext);
 526                         break;
 527                 }
 528
 529                 if (start == ext->start) {
 530                         ext->start += count;
 531                         ext->count -= count;
 532                         return 1;
 533                 }
 534         }
 535
 536         /* See if we should delete or truncate extent on the right */
 537         for (; parent != NULL; parent = node) {
 538                 node = ext2fs_rb_next(parent);
 539                 ext = node_to_extent(parent);
 540                 if ((ext->start + ext->count) <= start)
 541                         continue;
 542
 543                 /* No more extents to be removed/truncated */
 544                 if ((start + count) < ext->start)
 545                         break;
 546
 547                 /* The entire extent is within the region to be removed */
 548                 if ((start + count) >= (ext->start + ext->count)) {
 549                         ext2fs_rb_erase(parent, root);
 550                         rb_free_extent(bp, ext);
 551                         retval = 1;
 552                         continue;
 553                 } else {
 554                         /* modify the last extent in reigon to be removed */
 555                         ext->count -= ((start + count) - ext->start);
 556                         ext->start = start + count;
 557                         retval = 1;
 558                         break;
 559                 }
 560         }
 561
 562         return retval;
 563 }
 564
 565 static int rb_mark_bmap(ext2fs_generic_bitmap bitmap, __u64 arg)
 566 {
 567         struct ext2fs_rb_private *bp;
 568         int retval;
 569
 570         bp = (struct ext2fs_rb_private *) bitmap->private;
 571         arg -= bitmap->start;
 572
 573         retval = rb_insert_extent(arg, 1, bp);
 574         check_tree(&bp->root, __func__);
 575         return retval;
 576 }
 577
 578 static int rb_unmark_bmap(ext2fs_generic_bitmap bitmap, __u64 arg)
 579 {
 580         struct ext2fs_rb_private *bp;
 581         int retval;
 582
 583         bp = (struct ext2fs_rb_private *) bitmap->private;
 584         arg -= bitmap->start;
 585
 586         retval = rb_remove_extent(arg, 1, bp);
 587         check_tree(&bp->root, __func__);
 588
 589         return retval;
 590 }
 591
 592 inline
 593 static int rb_test_bmap(ext2fs_generic_bitmap bitmap, __u64 arg)
 594 {
 595         struct ext2fs_rb_private *bp;
 596
 597         bp = (struct ext2fs_rb_private *) bitmap->private;
 598         arg -= bitmap->start;
 599
 600         return rb_test_bit(bp, arg);
 601 }
 602
 603 static void rb_mark_bmap_extent(ext2fs_generic_bitmap bitmap, __u64 arg,
 604                                 unsigned int num)
 605 {
 606         struct ext2fs_rb_private *bp;
 607
 608         bp = (struct ext2fs_rb_private *) bitmap->private;
 609         arg -= bitmap->start;
 610
 611         rb_insert_extent(arg, num, bp);
 612         check_tree(&bp->root, __func__);
 613 }
 614
 615 static void rb_unmark_bmap_extent(ext2fs_generic_bitmap bitmap, __u64 arg,
 616                                   unsigned int num)
 617 {
 618         struct ext2fs_rb_private *bp;
 619
 620         bp = (struct ext2fs_rb_private *) bitmap->private;
 621         arg -= bitmap->start;
 622
 623         rb_remove_extent(arg, num, bp);
 624         check_tree(&bp->root, __func__);
 625 }
 626
 627 static int rb_test_clear_bmap_extent(ext2fs_generic_bitmap bitmap,
 628                                      __u64 start, unsigned int len)
 629 {
 630         struct rb_node *parent = NULL, **n;
 631         struct rb_node *node, *next;
 632         struct ext2fs_rb_private *bp;
 633         struct bmap_rb_extent *ext;
 634         int retval = 1;
 635
 636         bp = (struct ext2fs_rb_private *) bitmap->private;
 637         n = &bp->root.rb_node;
 638         start -= bitmap->start;
 639
 640         if ((len == 0) || EXT2FS_RB_EMPTY_ROOT(&bp->root))
 641                 return 1;
 642
 643         /*
 644          * If we find nothing, we should examine whole extent, but
 645          * when we find match, the extent is not clean, thus be return
 646          * false.
 647          */
 648         while (*n) {
 649                 parent = *n;
 650                 ext = node_to_extent(parent);
 651                 if (start < ext->start) {
 652                         n = &(*n)->rb_left;
 653                 } else if (start >= (ext->start + ext->count)) {
 654                         n = &(*n)->rb_right;
 655                 } else {
 656                         /*
 657                          * We found extent int the tree -> extent is not
 658                          * clean
 659                          */
 660                         return 0;
 661                 }
 662         }
 663
 664         node = parent;
 665         while (node) {
 666                 next = ext2fs_rb_next(node);
 667                 ext = node_to_extent(node);
 668                 node = next;
 669
 670                 if ((ext->start + ext->count) <= start)
 671                         continue;
 672
 673                 /* No more merging */
 674                 if ((start + len) <= ext->start)
 675                         break;
 676
 677                 retval = 0;
 678                 break;
 679         }
 680         return retval;
 681 }
 682
 683 static errcode_t rb_set_bmap_range(ext2fs_generic_bitmap bitmap,
 684                                      __u64 start, size_t num, void *in)
 685 {
 686         struct ext2fs_rb_private *bp;
 687         unsigned char *cp = in;
 688         size_t i;
 689         int first_set = -1;
 690
 691         bp = (struct ext2fs_rb_private *) bitmap->private;
 692
 693         for (i = 0; i < num; i++) {
 694                 if ((i & 7) == 0) {
 695                         unsigned char c = cp[i/8];
 696                         if (c == 0xFF) {
 697                                 if (first_set == -1)
 698                                         first_set = i;
 699                                 i += 7;
 700                                 continue;
 701                         }
 702                         if ((c == 0x00) && (first_set == -1)) {
 703                                 i += 7;
 704                                 continue;
 705                         }
 706                 }
 707                 if (ext2fs_test_bit(i, in)) {
 708                         if (first_set == -1)
 709                                 first_set = i;
 710                         continue;
 711                 }
 712                 if (first_set == -1)
 713                         continue;
 714
 715                 rb_insert_extent(start + first_set - bitmap->start,
 716                                  i - first_set, bp);
 717                 check_tree(&bp->root, __func__);
 718                 first_set = -1;
 719         }
 720         if (first_set != -1) {
 721                 rb_insert_extent(start + first_set - bitmap->start,
 722                                  num - first_set, bp);
 723                 check_tree(&bp->root, __func__);
 724         }
 725
 726         return 0;
 727 }
 728
 729 static errcode_t rb_get_bmap_range(ext2fs_generic_bitmap bitmap,
 730                                      __u64 start, size_t num, void *out)
 731 {
 732
 733         struct rb_node *parent = NULL, *next, **n;
 734         struct ext2fs_rb_private *bp;
 735         struct bmap_rb_extent *ext;
 736         __u64 count, pos;
 737
 738         bp = (struct ext2fs_rb_private *) bitmap->private;
 739         n = &bp->root.rb_node;
 740         start -= bitmap->start;
 741
 742         if (EXT2FS_RB_EMPTY_ROOT(&bp->root))
 743                 return 0;
 744
 745         while (*n) {
 746                 parent = *n;
 747                 ext = node_to_extent(parent);
 748                 if (start < ext->start) {
 749                         n = &(*n)->rb_left;
 750                 } else if (start >= (ext->start + ext->count)) {
 751                         n = &(*n)->rb_right;
 752                 } else
 753                         break;
 754         }
 755
 756         memset(out, 0, (num + 7) >> 3);
 757
 758         for (; parent != NULL; parent = next) {
 759                 next = ext2fs_rb_next(parent);
 760                 ext = node_to_extent(parent);
 761
 762                 pos = ext->start;
 763                 count = ext->count;
 764                 if (pos >= start + num)
 765                         break;
 766                 if (pos < start) {
 767                         if (pos + count <  start)
 768                                 continue;
 769                         count -= start - pos;
 770                         pos = start;
 771                 }
 772                 if (pos + count > start + num)
 773                         count = start + num - pos;
 774
 775                 while (count > 0) {
 776                         if ((count >= 8) &&
 777                             ((pos - start) % 8) == 0) {
 778                                 int nbytes = count >> 3;
 779                                 int offset = (pos - start) >> 3;
 780
 781                                 memset(((char *) out) + offset, 0xFF, nbytes);
 782                                 pos += nbytes << 3;
 783                                 count -= nbytes << 3;
 784                                 continue;
 785                         }
 786                         ext2fs_fast_set_bit64((pos - start), out);
 787                         pos++;
 788                         count--;
 789                 }
 790         }
 791         return 0;
 792 }
 793
 794 static void rb_clear_bmap(ext2fs_generic_bitmap bitmap)
 795 {
 796         struct ext2fs_rb_private *bp;
 797
 798         bp = (struct ext2fs_rb_private *) bitmap->private;
 799
 800         rb_free_tree(&bp->root);
 801         bp->rcursor = NULL;
 802         bp->rcursor_next = NULL;
 803         bp->wcursor = NULL;
 804         check_tree(&bp->root, __func__);
 805 }
 806
 807 static errcode_t rb_find_first_zero(ext2fs_generic_bitmap bitmap,
 808                                    __u64 start, __u64 end, __u64 *out)
 809 {
 810         struct rb_node *parent = NULL, **n;
 811         struct ext2fs_rb_private *bp;
 812         struct bmap_rb_extent *ext;
 813
 814         bp = (struct ext2fs_rb_private *) bitmap->private;
 815         n = &bp->root.rb_node;
 816         start -= bitmap->start;
 817         end -= bitmap->start;
 818
 819         if (start > end)
 820                 return EINVAL;
 821
 822         if (EXT2FS_RB_EMPTY_ROOT(&bp->root))
 823                 return ENOENT;
 824
 825         while (*n) {
 826                 parent = *n;
 827                 ext = node_to_extent(parent);
 828                 if (start < ext->start) {
 829                         n = &(*n)->rb_left;
 830                 } else if (start >= (ext->start + ext->count)) {
 831                         n = &(*n)->rb_right;
 832                 } else if (ext->start + ext->count <= end) {
 833                         *out = ext->start + ext->count + bitmap->start;
 834                         return 0;
 835                 } else
 836                         return ENOENT;
 837         }
 838
 839         *out = start + bitmap->start;
 840         return 0;
 841 }
 842
 843 static errcode_t rb_find_first_set(ext2fs_generic_bitmap bitmap,
 844                                    __u64 start, __u64 end, __u64 *out)
 845 {
 846         struct rb_node *parent = NULL, **n;
 847         struct rb_node *node;
 848         struct ext2fs_rb_private *bp;
 849         struct bmap_rb_extent *ext;
 850
 851         bp = (struct ext2fs_rb_private *) bitmap->private;
 852         n = &bp->root.rb_node;
 853         start -= bitmap->start;
 854         end -= bitmap->start;
 855
 856         if (start > end)
 857                 return EINVAL;
 858
 859         if (EXT2FS_RB_EMPTY_ROOT(&bp->root))
 860                 return ENOENT;
 861
 862         while (*n) {
 863                 parent = *n;
 864                 ext = node_to_extent(parent);
 865                 if (start < ext->start) {
 866                         n = &(*n)->rb_left;
 867                 } else if (start >= (ext->start + ext->count)) {
 868                         n = &(*n)->rb_right;
 869                 } else {
 870                         /* The start bit is set */
 871                         *out = start + bitmap->start;
 872                         return 0;
 873                 }
 874         }
 875
 876         node = parent;
 877         ext = node_to_extent(node);
 878         if (ext->start < start) {
 879                 node = ext2fs_rb_next(node);
 880                 if (node == NULL)
 881                         return ENOENT;
 882                 ext = node_to_extent(node);
 883         }
 884         if (ext->start <= end) {
 885                 *out = ext->start + bitmap->start;
 886                 return 0;
 887         }
 888         return ENOENT;
 889 }
 890
 891 #ifdef ENABLE_BMAP_STATS
 892 static void rb_print_stats(ext2fs_generic_bitmap bitmap)
 893 {
 894         struct ext2fs_rb_private *bp;
 895         struct rb_node *node = NULL;
 896         struct bmap_rb_extent *ext;
 897         __u64 count = 0;
 898         __u64 max_size = 0;
 899         __u64 min_size = ULONG_MAX;
 900         __u64 size = 0, avg_size = 0;
 901         double eff;
 902 #ifdef ENABLE_BMAP_STATS_OPS
 903         __u64 mark_all, test_all;
 904         double m_hit = 0.0, t_hit = 0.0;
 905 #endif
 906
 907         bp = (struct ext2fs_rb_private *) bitmap->private;
 908
 909         for (node = ext2fs_rb_first(&bp->root); node != NULL;
 910              node = ext2fs_rb_next(node)) {
 911                 ext = node_to_extent(node);
 912                 count++;
 913                 if (ext->count > max_size)
 914                         max_size = ext->count;
 915                 if (ext->count < min_size)
 916                         min_size = ext->count;
 917                 size += ext->count;
 918         }
 919
 920         if (count)
 921                 avg_size = size / count;
 922         if (min_size == ULONG_MAX)
 923                 min_size = 0;
 924         eff = (double)((count * sizeof(struct bmap_rb_extent)) << 3) /
 925               (bitmap->real_end - bitmap->start);
 926 #ifdef ENABLE_BMAP_STATS_OPS
 927         mark_all = bitmap->stats.mark_count + bitmap->stats.mark_ext_count;
 928         test_all = bitmap->stats.test_count + bitmap->stats.test_ext_count;
 929         if (mark_all)
 930                 m_hit = ((double)bp->mark_hit / mark_all) * 100;
 931         if (test_all)
 932                 t_hit = ((double)bp->test_hit / test_all) * 100;
 933
 934         fprintf(stderr, "%16llu cache hits on test (%.2f%%)\n"
 935                 "%16llu cache hits on mark (%.2f%%)\n",
 936                 bp->test_hit, t_hit, bp->mark_hit, m_hit);
 937 #endif
 938         fprintf(stderr, "%16llu extents (%llu bytes)\n",
 939                 count, ((count * sizeof(struct bmap_rb_extent)) +
 940                         sizeof(struct ext2fs_rb_private)));
 941         fprintf(stderr, "%16llu bits minimum size\n",
 942                 min_size);
 943         fprintf(stderr, "%16llu bits maximum size\n"
 944                 "%16llu bits average size\n",
 945                 max_size, avg_size);
 946         fprintf(stderr, "%16llu bits set in bitmap (out of %llu)\n", size,
 947                 bitmap->real_end - bitmap->start);
 948         fprintf(stderr,
 949                 "%16.4lf memory / bitmap bit memory ratio (bitarray = 1)\n",
 950                 eff);
 951 }
 952 #else
 953 static void rb_print_stats(ext2fs_generic_bitmap bitmap EXT2FS_ATTR((unused)))
 954 {
 955 }
 956 #endif
 957
 958 struct ext2_bitmap_ops ext2fs_blkmap64_rbtree = {
 959         .type = EXT2FS_BMAP64_RBTREE,
 960         .new_bmap = rb_new_bmap,
 961         .free_bmap = rb_free_bmap,
 962         .copy_bmap = rb_copy_bmap,
 963         .resize_bmap = rb_resize_bmap,
 964         .mark_bmap = rb_mark_bmap,
 965         .unmark_bmap = rb_unmark_bmap,
 966         .test_bmap = rb_test_bmap,
 967         .test_clear_bmap_extent = rb_test_clear_bmap_extent,
 968         .mark_bmap_extent = rb_mark_bmap_extent,
 969         .unmark_bmap_extent = rb_unmark_bmap_extent,
 970         .set_bmap_range = rb_set_bmap_range,
 971         .get_bmap_range = rb_get_bmap_range,
 972         .clear_bmap = rb_clear_bmap,
 973         .print_stats = rb_print_stats,
 974         .find_first_zero = rb_find_first_zero,
 975         .find_first_set = rb_find_first_set,
 976 };