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 *new_node, *node, *next;
  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 crazy\n");
  94                         printf("extent: %llu -> %llu (%u)\n", ext->start,
  95                                 ext->start + ext->count, ext->count);
  96                         goto err_out;
  97                 }
  98                 if (ext->start < 0) {
  99                         printf("Tree Error: start is crazy\n");
 100                         printf("extent: %llu -> %llu (%u)\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 (%u)\n",
 109                                         old->start, old->start + old->count,
 110                                         old->count);
 111                                 printf("extent next: %llu -> %llu (%u)\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 (%u)\n",
 119                                         old->start, old->start + old->count,
 120                                         old->count);
 121                                 printf("extent next: %llu -> %llu (%u)\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, msg) 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         if (new_real_end >= bmap->real_end) {
 301                 bmap->end = new_end;
 302                 bmap->real_end = new_real_end;
 303                 return 0;
 304         }
 305
 306         bp = (struct ext2fs_rb_private *) bmap->private;
 307         bp->rcursor = NULL;
 308         bp->wcursor = NULL;
 309
 310         /* truncate tree to new_real_end size */
 311         rb_truncate(new_real_end, &bp->root);
 312
 313         bmap->end = new_end;
 314         bmap->real_end = new_real_end;
 315         return 0;
 316
 317 }
 318
 319 inline static int
 320 rb_test_bit(struct ext2fs_rb_private *bp, __u64 bit)
 321 {
 322         struct bmap_rb_extent *rcursor, *next_ext = NULL;
 323         struct rb_node *parent = NULL, *next;
 324         struct rb_node **n = &bp->root.rb_node;
 325         struct bmap_rb_extent *ext;
 326
 327         rcursor = bp->rcursor;
 328         if (!rcursor)
 329                 goto search_tree;
 330
 331         if (bit >= rcursor->start && bit < rcursor->start + rcursor->count) {
 332 #ifdef ENABLE_BMAP_STATS_OPS
 333                 bp->test_hit++;
 334 #endif
 335                 return 1;
 336         }
 337
 338         next_ext = bp->rcursor_next;
 339         if (!next_ext) {
 340                 next = ext2fs_rb_next(&rcursor->node);
 341                 if (next)
 342                         next_ext = node_to_extent(next);
 343                 bp->rcursor_next = next_ext;
 344         }
 345         if (next_ext) {
 346                 if ((bit >= rcursor->start + rcursor->count) &&
 347                     (bit < next_ext->start)) {
 348 #ifdef BMAP_STATS_OPS
 349                         bp->test_hit++;
 350 #endif
 351                         return 0;
 352                 }
 353         }
 354         bp->rcursor = NULL;
 355         bp->rcursor_next = NULL;
 356
 357         rcursor = bp->wcursor;
 358         if (!rcursor)
 359                 goto search_tree;
 360
 361         if (bit >= rcursor->start && bit < rcursor->start + rcursor->count)
 362                 return 1;
 363
 364 search_tree:
 365
 366         while (*n) {
 367                 parent = *n;
 368                 ext = node_to_extent(parent);
 369                 if (bit < ext->start)
 370                         n = &(*n)->rb_left;
 371                 else if (bit >= (ext->start + ext->count))
 372                         n = &(*n)->rb_right;
 373                 else {
 374                         bp->rcursor = ext;
 375                         bp->rcursor_next = NULL;
 376                         return 1;
 377                 }
 378         }
 379         return 0;
 380 }
 381
 382 static int rb_insert_extent(__u64 start, __u64 count,
 383                             struct ext2fs_rb_private *bp)
 384 {
 385         struct rb_root *root = &bp->root;
 386         struct rb_node *parent = NULL, **n = &root->rb_node;
 387         struct rb_node *new_node, *node, *next;
 388         struct bmap_rb_extent *new_ext;
 389         struct bmap_rb_extent *ext;
 390         int retval = 0;
 391
 392         bp->rcursor_next = NULL;
 393         ext = bp->wcursor;
 394         if (ext) {
 395                 if (start >= ext->start &&
 396                     start <= (ext->start + ext->count)) {
 397 #ifdef ENABLE_BMAP_STATS_OPS
 398                         bp->mark_hit++;
 399 #endif
 400                         goto got_extent;
 401                 }
 402         }
 403
 404         while (*n) {
 405                 parent = *n;
 406                 ext = node_to_extent(parent);
 407
 408                 if (start < ext->start) {
 409                         n = &(*n)->rb_left;
 410                 } else if (start > (ext->start + ext->count)) {
 411                         n = &(*n)->rb_right;
 412                 } else {
 413 got_extent:
 414                         if ((start + count) <= (ext->start + ext->count))
 415                                 return 1;
 416
 417                         if ((ext->start + ext->count) == start)
 418                                 retval = 0;
 419                         else
 420                                 retval = 1;
 421
 422                         count += (start - ext->start);
 423                         start = ext->start;
 424                         new_ext = ext;
 425                         new_node = &ext->node;
 426
 427                         goto skip_insert;
 428                 }
 429         }
 430
 431         rb_get_new_extent(&new_ext, start, count);
 432
 433         new_node = &new_ext->node;
 434         ext2fs_rb_link_node(new_node, parent, n);
 435         ext2fs_rb_insert_color(new_node, root);
 436         bp->wcursor = new_ext;
 437
 438         node = ext2fs_rb_prev(new_node);
 439         if (node) {
 440                 ext = node_to_extent(node);
 441                 if ((ext->start + ext->count) == start) {
 442                         start = ext->start;
 443                         count += ext->count;
 444                         ext2fs_rb_erase(node, root);
 445                         rb_free_extent(bp, ext);
 446                 }
 447         }
 448
 449 skip_insert:
 450         /* See if we can merge extent to the right */
 451         for (node = ext2fs_rb_next(new_node); node != NULL; node = next) {
 452                 next = ext2fs_rb_next(node);
 453                 ext = node_to_extent(node);
 454
 455                 if ((ext->start + ext->count) <= start)
 456                         continue;
 457
 458                 /* No more merging */
 459                 if ((start + count) < ext->start)
 460                         break;
 461
 462                 /* ext is embedded in new_ext interval */
 463                 if ((start + count) >= (ext->start + ext->count)) {
 464                         ext2fs_rb_erase(node, root);
 465                         rb_free_extent(bp, ext);
 466                         continue;
 467                 } else {
 468                 /* merge ext with new_ext */
 469                         count += ((ext->start + ext->count) -
 470                                   (start + count));
 471                         ext2fs_rb_erase(node, root);
 472                         rb_free_extent(bp, ext);
 473                         break;
 474                 }
 475         }
 476
 477         new_ext->start = start;
 478         new_ext->count = count;
 479
 480         return retval;
 481 }
 482
 483 static int rb_remove_extent(__u64 start, __u64 count,
 484                             struct ext2fs_rb_private *bp)
 485 {
 486         struct rb_root *root = &bp->root;
 487         struct rb_node *parent = NULL, **n = &root->rb_node;
 488         struct rb_node *node;
 489         struct bmap_rb_extent *ext;
 490         __u64 new_start, new_count;
 491         int retval = 0;
 492
 493         if (EXT2FS_RB_EMPTY_ROOT(root))
 494                 return 0;
 495
 496         while (*n) {
 497                 parent = *n;
 498                 ext = node_to_extent(parent);
 499                 if (start < ext->start) {
 500                         n = &(*n)->rb_left;
 501                         continue;
 502                 } else if (start >= (ext->start + ext->count)) {
 503                         n = &(*n)->rb_right;
 504                         continue;
 505                 }
 506
 507                 if ((start > ext->start) &&
 508                     (start + count) < (ext->start + ext->count)) {
 509                         /* We have to split extent into two */
 510                         new_start = start + count;
 511                         new_count = (ext->start + ext->count) - new_start;
 512
 513                         ext->count = start - ext->start;
 514
 515                         rb_insert_extent(new_start, new_count, bp);
 516                         return 1;
 517                 }
 518
 519                 if ((start + count) >= (ext->start + ext->count)) {
 520                         ext->count = start - ext->start;
 521                         retval = 1;
 522                 }
 523
 524                 if (0 == ext->count) {
 525                         parent = ext2fs_rb_next(&ext->node);
 526                         ext2fs_rb_erase(&ext->node, root);
 527                         rb_free_extent(bp, ext);
 528                         break;
 529                 }
 530
 531                 if (start == ext->start) {
 532                         ext->start += count;
 533                         ext->count -= count;
 534                         return 1;
 535                 }
 536         }
 537
 538         /* See if we should delete or truncate extent on the right */
 539         for (; parent != NULL; parent = node) {
 540                 node = ext2fs_rb_next(parent);
 541                 ext = node_to_extent(parent);
 542                 if ((ext->start + ext->count) <= start)
 543                         continue;
 544
 545                 /* No more extents to be removed/truncated */
 546                 if ((start + count) < ext->start)
 547                         break;
 548
 549                 /* The entire extent is within the region to be removed */
 550                 if ((start + count) >= (ext->start + ext->count)) {
 551                         ext2fs_rb_erase(parent, root);
 552                         rb_free_extent(bp, ext);
 553                         retval = 1;
 554                         continue;
 555                 } else {
 556                         /* modify the last extent in reigon to be removed */
 557                         ext->count -= ((start + count) - ext->start);
 558                         ext->start = start + count;
 559                         retval = 1;
 560                         break;
 561                 }
 562         }
 563
 564         return retval;
 565 }
 566
 567 static int rb_mark_bmap(ext2fs_generic_bitmap bitmap, __u64 arg)
 568 {
 569         struct ext2fs_rb_private *bp;
 570
 571         bp = (struct ext2fs_rb_private *) bitmap->private;
 572         arg -= bitmap->start;
 573
 574         return rb_insert_extent(arg, 1, bp);
 575 }
 576
 577 static int rb_unmark_bmap(ext2fs_generic_bitmap bitmap, __u64 arg)
 578 {
 579         struct ext2fs_rb_private *bp;
 580         int retval;
 581
 582         bp = (struct ext2fs_rb_private *) bitmap->private;
 583         arg -= bitmap->start;
 584
 585         retval = rb_remove_extent(arg, 1, bp);
 586         check_tree(&bp->root, __func__);
 587
 588         return retval;
 589 }
 590
 591 inline
 592 static int rb_test_bmap(ext2fs_generic_bitmap bitmap, __u64 arg)
 593 {
 594         struct ext2fs_rb_private *bp;
 595
 596         bp = (struct ext2fs_rb_private *) bitmap->private;
 597         arg -= bitmap->start;
 598
 599         return rb_test_bit(bp, arg);
 600 }
 601
 602 static void rb_mark_bmap_extent(ext2fs_generic_bitmap bitmap, __u64 arg,
 603                                 unsigned int num)
 604 {
 605         struct ext2fs_rb_private *bp;
 606
 607         bp = (struct ext2fs_rb_private *) bitmap->private;
 608         arg -= bitmap->start;
 609
 610         rb_insert_extent(arg, num, bp);
 611 }
 612
 613 static void rb_unmark_bmap_extent(ext2fs_generic_bitmap bitmap, __u64 arg,
 614                                   unsigned int num)
 615 {
 616         struct ext2fs_rb_private *bp;
 617
 618         bp = (struct ext2fs_rb_private *) bitmap->private;
 619         arg -= bitmap->start;
 620
 621         rb_remove_extent(arg, num, bp);
 622         check_tree(&bp->root, __func__);
 623 }
 624
 625 static int rb_test_clear_bmap_extent(ext2fs_generic_bitmap bitmap,
 626                                      __u64 start, unsigned int len)
 627 {
 628         struct rb_node *parent = NULL, **n;
 629         struct rb_node *node, *next;
 630         struct ext2fs_rb_private *bp;
 631         struct bmap_rb_extent *ext;
 632         int retval = 1;
 633
 634         bp = (struct ext2fs_rb_private *) bitmap->private;
 635         n = &bp->root.rb_node;
 636         start -= bitmap->start;
 637
 638         if ((len == 0) || EXT2FS_RB_EMPTY_ROOT(&bp->root))
 639                 return 1;
 640
 641         /*
 642          * If we find nothing, we should examine whole extent, but
 643          * when we find match, the extent is not clean, thus be return
 644          * false.
 645          */
 646         while (*n) {
 647                 parent = *n;
 648                 ext = node_to_extent(parent);
 649                 if (start < ext->start) {
 650                         n = &(*n)->rb_left;
 651                 } else if (start >= (ext->start + ext->count)) {
 652                         n = &(*n)->rb_right;
 653                 } else {
 654                         /*
 655                          * We found extent int the tree -> extent is not
 656                          * clean
 657                          */
 658                         return 0;
 659                 }
 660         }
 661
 662         node = parent;
 663         while (node) {
 664                 next = ext2fs_rb_next(node);
 665                 ext = node_to_extent(node);
 666                 node = next;
 667
 668                 if ((ext->start + ext->count) <= start)
 669                         continue;
 670
 671                 /* No more merging */
 672                 if ((start + len) <= ext->start)
 673                         break;
 674
 675                 retval = 0;
 676                 break;
 677         }
 678         return retval;
 679 }
 680
 681 static errcode_t rb_set_bmap_range(ext2fs_generic_bitmap bitmap,
 682                                      __u64 start, size_t num, void *in)
 683 {
 684         struct ext2fs_rb_private *bp;
 685         unsigned char *cp = in;
 686         size_t i;
 687         int first_set = -1;
 688
 689         bp = (struct ext2fs_rb_private *) bitmap->private;
 690
 691         for (i = 0; i < num; i++) {
 692                 if ((i & 7) == 0) {
 693                         unsigned char c = cp[i/8];
 694                         if (c == 0xFF) {
 695                                 if (first_set == -1)
 696                                         first_set = i;
 697                                 i += 7;
 698                                 continue;
 699                         }
 700                         if ((c == 0x00) && (first_set == -1)) {
 701                                 i += 7;
 702                                 continue;
 703                         }
 704                 }
 705                 if (ext2fs_test_bit(i, in)) {
 706                         if (first_set == -1)
 707                                 first_set = i;
 708                         continue;
 709                 }
 710                 if (first_set == -1)
 711                         continue;
 712
 713                 rb_insert_extent(start + first_set - bitmap->start,
 714                                  i - first_set, bp);
 715                 first_set = -1;
 716         }
 717         if (first_set != -1)
 718                 rb_insert_extent(start + first_set - bitmap->start,
 719                                  num - first_set, bp);
 720
 721         return 0;
 722 }
 723
 724 static errcode_t rb_get_bmap_range(ext2fs_generic_bitmap bitmap,
 725                                      __u64 start, size_t num, void *out)
 726 {
 727
 728         struct rb_node *parent = NULL, *next, **n;
 729         struct ext2fs_rb_private *bp;
 730         struct bmap_rb_extent *ext;
 731         int count;
 732         __u64 pos;
 733
 734         bp = (struct ext2fs_rb_private *) bitmap->private;
 735         n = &bp->root.rb_node;
 736         start -= bitmap->start;
 737
 738         if (EXT2FS_RB_EMPTY_ROOT(&bp->root))
 739                 return 0;
 740
 741         while (*n) {
 742                 parent = *n;
 743                 ext = node_to_extent(parent);
 744                 if (start < ext->start) {
 745                         n = &(*n)->rb_left;
 746                 } else if (start >= (ext->start + ext->count)) {
 747                         n = &(*n)->rb_right;
 748                 } else
 749                         break;
 750         }
 751
 752         memset(out, 0, (num + 7) >> 3);
 753
 754         for (; parent != NULL; parent = next) {
 755                 next = ext2fs_rb_next(parent);
 756                 ext = node_to_extent(parent);
 757
 758                 pos = ext->start;
 759                 count = ext->count;
 760                 if (pos >= start + num)
 761                         break;
 762                 if (pos < start) {
 763                         count -= start - pos;
 764                         if (count < 0)
 765                                 continue;
 766                         pos = start;
 767                 }
 768                 if (pos + count > start + num)
 769                         count = start + num - pos;
 770
 771                 while (count > 0) {
 772                         if ((count >= 8) &&
 773                             ((pos - start) % 8) == 0) {
 774                                 int nbytes = count >> 3;
 775                                 int offset = (pos - start) >> 3;
 776
 777                                 memset(((char *) out) + offset, 0xFF, nbytes);
 778                                 pos += nbytes << 3;
 779                                 count -= nbytes << 3;
 780                                 continue;
 781                         }
 782                         ext2fs_fast_set_bit64((pos - start), out);
 783                         pos++;
 784                         count--;
 785                 }
 786         }
 787         return 0;
 788 }
 789
 790 static void rb_clear_bmap(ext2fs_generic_bitmap bitmap)
 791 {
 792         struct ext2fs_rb_private *bp;
 793
 794         bp = (struct ext2fs_rb_private *) bitmap->private;
 795
 796         rb_free_tree(&bp->root);
 797         bp->rcursor = NULL;
 798         bp->rcursor_next = NULL;
 799         bp->wcursor = NULL;
 800 }
 801
 802 #ifdef ENABLE_BMAP_STATS
 803 static void rb_print_stats(ext2fs_generic_bitmap bitmap)
 804 {
 805         struct ext2fs_rb_private *bp;
 806         struct rb_node *node = NULL;
 807         struct bmap_rb_extent *ext;
 808         __u64 count = 0;
 809         __u64 max_size = 0;
 810         __u64 min_size = ULONG_MAX;
 811         __u64 size = 0, avg_size = 0;
 812         double eff;
 813 #ifdef ENABLE_BMAP_STATS_OPS
 814         __u64 mark_all, test_all;
 815         double m_hit = 0.0, t_hit = 0.0;
 816 #endif
 817
 818         bp = (struct ext2fs_rb_private *) bitmap->private;
 819
 820         for (node = ext2fs_rb_first(&bp->root); node != NULL;
 821              node = ext2fs_rb_next(node)) {
 822                 ext = node_to_extent(node);
 823                 count++;
 824                 if (ext->count > max_size)
 825                         max_size = ext->count;
 826                 if (ext->count < min_size)
 827                         min_size = ext->count;
 828                 size += ext->count;
 829         }
 830
 831         if (count)
 832                 avg_size = size / count;
 833         if (min_size == ULONG_MAX)
 834                 min_size = 0;
 835         eff = (double)((count * sizeof(struct bmap_rb_extent)) << 3) /
 836               (bitmap->real_end - bitmap->start);
 837 #ifdef ENABLE_BMAP_STATS_OPS
 838         mark_all = bitmap->stats.mark_count + bitmap->stats.mark_ext_count;
 839         test_all = bitmap->stats.test_count + bitmap->stats.test_ext_count;
 840         if (mark_all)
 841                 m_hit = ((double)bp->mark_hit / mark_all) * 100;
 842         if (test_all)
 843                 t_hit = ((double)bp->test_hit / test_all) * 100;
 844
 845         fprintf(stderr, "%16llu cache hits on test (%.2f%%)\n"
 846                 "%16llu cache hits on mark (%.2f%%)\n",
 847                 bp->test_hit, t_hit, bp->mark_hit, m_hit);
 848 #endif
 849         fprintf(stderr, "%16llu extents (%llu bytes)\n",
 850                 count, ((count * sizeof(struct bmap_rb_extent)) +
 851                         sizeof(struct ext2fs_rb_private)));
 852         fprintf(stderr, "%16llu bits minimum size\n",
 853                 min_size);
 854         fprintf(stderr, "%16llu bits maximum size\n"
 855                 "%16llu bits average size\n",
 856                 max_size, avg_size);
 857         fprintf(stderr, "%16llu bits set in bitmap (out of %llu)\n", size,
 858                 bitmap->real_end - bitmap->start);
 859         fprintf(stderr,
 860                 "%16.4lf memory / bitmap bit memory ratio (bitarray = 1)\n",
 861                 eff);
 862 }
 863 #else
 864 static void rb_print_stats(ext2fs_generic_bitmap bitmap EXT2FS_ATTR((unused)))
 865 {
 866 }
 867 #endif
 868
 869 struct ext2_bitmap_ops ext2fs_blkmap64_rbtree = {
 870         .type = EXT2FS_BMAP64_RBTREE,
 871         .new_bmap = rb_new_bmap,
 872         .free_bmap = rb_free_bmap,
 873         .copy_bmap = rb_copy_bmap,
 874         .resize_bmap = rb_resize_bmap,
 875         .mark_bmap = rb_mark_bmap,
 876         .unmark_bmap = rb_unmark_bmap,
 877         .test_bmap = rb_test_bmap,
 878         .test_clear_bmap_extent = rb_test_clear_bmap_extent,
 879         .mark_bmap_extent = rb_mark_bmap_extent,
 880         .unmark_bmap_extent = rb_unmark_bmap_extent,
 881         .set_bmap_range = rb_set_bmap_range,
 882         .get_bmap_range = rb_get_bmap_range,
 883         .clear_bmap = rb_clear_bmap,
 884         .print_stats = rb_print_stats,
 885 };