1 /* 2 * Copyright (c) 2007-2008 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * $DragonFly: src/sys/vfs/hammer/hammer_btree.c,v 1.76 2008/08/06 15:38:58 dillon Exp $ 35 */ 36 37 /* 38 * HAMMER B-Tree index 39 * 40 * HAMMER implements a modified B+Tree. In documentation this will 41 * simply be refered to as the HAMMER B-Tree. Basically a HAMMER B-Tree 42 * looks like a B+Tree (A B-Tree which stores its records only at the leafs 43 * of the tree), but adds two additional boundary elements which describe 44 * the left-most and right-most element a node is able to represent. In 45 * otherwords, we have boundary elements at the two ends of a B-Tree node 46 * instead of sub-tree pointers. 47 * 48 * A B-Tree internal node looks like this: 49 * 50 * B N N N N N N B <-- boundary and internal elements 51 * S S S S S S S <-- subtree pointers 52 * 53 * A B-Tree leaf node basically looks like this: 54 * 55 * L L L L L L L L <-- leaf elemenets 56 * 57 * The radix for an internal node is 1 less then a leaf but we get a 58 * number of significant benefits for our troubles. 59 * 60 * The big benefit to using a B-Tree containing boundary information 61 * is that it is possible to cache pointers into the middle of the tree 62 * and not have to start searches, insertions, OR deletions at the root 63 * node. In particular, searches are able to progress in a definitive 64 * direction from any point in the tree without revisting nodes. This 65 * greatly improves the efficiency of many operations, most especially 66 * record appends. 67 * 68 * B-Trees also make the stacking of trees fairly straightforward. 69 * 70 * INSERTIONS: A search performed with the intention of doing 71 * an insert will guarantee that the terminal leaf node is not full by 72 * splitting full nodes. Splits occur top-down during the dive down the 73 * B-Tree. 74 * 75 * DELETIONS: A deletion makes no attempt to proactively balance the 76 * tree and will recursively remove nodes that become empty. If a 77 * deadlock occurs a deletion may not be able to remove an empty leaf. 78 * Deletions never allow internal nodes to become empty (that would blow 79 * up the boundaries). 80 */ 81 #include "hammer.h" 82 #include <sys/buf.h> 83 #include <sys/buf2.h> 84 85 static int btree_search(hammer_cursor_t cursor, int flags); 86 static int btree_split_internal(hammer_cursor_t cursor); 87 static int btree_split_leaf(hammer_cursor_t cursor); 88 static int btree_remove(hammer_cursor_t cursor); 89 static int btree_node_is_full(hammer_node_ondisk_t node); 90 static int hammer_btree_mirror_propagate(hammer_cursor_t cursor, 91 hammer_tid_t mirror_tid); 92 static void hammer_make_separator(hammer_base_elm_t key1, 93 hammer_base_elm_t key2, hammer_base_elm_t dest); 94 static void hammer_cursor_mirror_filter(hammer_cursor_t cursor); 95 96 /* 97 * Iterate records after a search. The cursor is iterated forwards past 98 * the current record until a record matching the key-range requirements 99 * is found. ENOENT is returned if the iteration goes past the ending 100 * key. 101 * 102 * The iteration is inclusive of key_beg and can be inclusive or exclusive 103 * of key_end depending on whether HAMMER_CURSOR_END_INCLUSIVE is set. 104 * 105 * When doing an as-of search (cursor->asof != 0), key_beg.create_tid 106 * may be modified by B-Tree functions. 107 * 108 * cursor->key_beg may or may not be modified by this function during 109 * the iteration. XXX future - in case of an inverted lock we may have 110 * to reinitiate the lookup and set key_beg to properly pick up where we 111 * left off. 112 * 113 * NOTE! EDEADLK *CANNOT* be returned by this procedure. 114 */ 115 int 116 hammer_btree_iterate(hammer_cursor_t cursor) 117 { 118 hammer_node_ondisk_t node; 119 hammer_btree_elm_t elm; 120 int error = 0; 121 int r; 122 int s; 123 124 /* 125 * Skip past the current record 126 */ 127 node = cursor->node->ondisk; 128 if (node == NULL) 129 return(ENOENT); 130 if (cursor->index < node->count && 131 (cursor->flags & HAMMER_CURSOR_ATEDISK)) { 132 ++cursor->index; 133 } 134 135 /* 136 * Loop until an element is found or we are done. 137 */ 138 for (;;) { 139 /* 140 * We iterate up the tree and then index over one element 141 * while we are at the last element in the current node. 142 * 143 * If we are at the root of the filesystem, cursor_up 144 * returns ENOENT. 145 * 146 * XXX this could be optimized by storing the information in 147 * the parent reference. 148 * 149 * XXX we can lose the node lock temporarily, this could mess 150 * up our scan. 151 */ 152 ++hammer_stats_btree_iterations; 153 hammer_flusher_clean_loose_ios(cursor->trans->hmp); 154 155 if (cursor->index == node->count) { 156 if (hammer_debug_btree) { 157 kprintf("BRACKETU %016llx[%d] -> %016llx[%d] (td=%p)\n", 158 cursor->node->node_offset, 159 cursor->index, 160 (cursor->parent ? cursor->parent->node_offset : -1), 161 cursor->parent_index, 162 curthread); 163 } 164 KKASSERT(cursor->parent == NULL || cursor->parent->ondisk->elms[cursor->parent_index].internal.subtree_offset == cursor->node->node_offset); 165 error = hammer_cursor_up(cursor); 166 if (error) 167 break; 168 /* reload stale pointer */ 169 node = cursor->node->ondisk; 170 KKASSERT(cursor->index != node->count); 171 172 /* 173 * If we are reblocking we want to return internal 174 * nodes. 175 */ 176 if (cursor->flags & HAMMER_CURSOR_REBLOCKING) { 177 cursor->flags |= HAMMER_CURSOR_ATEDISK; 178 return(0); 179 } 180 ++cursor->index; 181 continue; 182 } 183 184 /* 185 * Check internal or leaf element. Determine if the record 186 * at the cursor has gone beyond the end of our range. 187 * 188 * We recurse down through internal nodes. 189 */ 190 if (node->type == HAMMER_BTREE_TYPE_INTERNAL) { 191 elm = &node->elms[cursor->index]; 192 193 r = hammer_btree_cmp(&cursor->key_end, &elm[0].base); 194 s = hammer_btree_cmp(&cursor->key_beg, &elm[1].base); 195 if (hammer_debug_btree) { 196 kprintf("BRACKETL %016llx[%d] %016llx %02x %016llx lo=%02x %d (td=%p)\n", 197 cursor->node->node_offset, 198 cursor->index, 199 elm[0].internal.base.obj_id, 200 elm[0].internal.base.rec_type, 201 elm[0].internal.base.key, 202 elm[0].internal.base.localization, 203 r, 204 curthread 205 ); 206 kprintf("BRACKETR %016llx[%d] %016llx %02x %016llx lo=%02x %d\n", 207 cursor->node->node_offset, 208 cursor->index + 1, 209 elm[1].internal.base.obj_id, 210 elm[1].internal.base.rec_type, 211 elm[1].internal.base.key, 212 elm[1].internal.base.localization, 213 s 214 ); 215 } 216 217 if (r < 0) { 218 error = ENOENT; 219 break; 220 } 221 if (r == 0 && (cursor->flags & 222 HAMMER_CURSOR_END_INCLUSIVE) == 0) { 223 error = ENOENT; 224 break; 225 } 226 KKASSERT(s <= 0); 227 228 /* 229 * Better not be zero 230 */ 231 KKASSERT(elm->internal.subtree_offset != 0); 232 233 /* 234 * If running the mirror filter see if we can skip 235 * one or more entire sub-trees. If we can we 236 * return the internal mode and the caller processes 237 * the skipped range (see mirror_read) 238 */ 239 if (cursor->flags & HAMMER_CURSOR_MIRROR_FILTERED) { 240 if (elm->internal.mirror_tid < 241 cursor->cmirror->mirror_tid) { 242 hammer_cursor_mirror_filter(cursor); 243 return(0); 244 } 245 } 246 247 error = hammer_cursor_down(cursor); 248 if (error) 249 break; 250 KKASSERT(cursor->index == 0); 251 /* reload stale pointer */ 252 node = cursor->node->ondisk; 253 continue; 254 } else { 255 elm = &node->elms[cursor->index]; 256 r = hammer_btree_cmp(&cursor->key_end, &elm->base); 257 if (hammer_debug_btree) { 258 kprintf("ELEMENT %016llx:%d %c %016llx %02x %016llx lo=%02x %d\n", 259 cursor->node->node_offset, 260 cursor->index, 261 (elm[0].leaf.base.btype ? 262 elm[0].leaf.base.btype : '?'), 263 elm[0].leaf.base.obj_id, 264 elm[0].leaf.base.rec_type, 265 elm[0].leaf.base.key, 266 elm[0].leaf.base.localization, 267 r 268 ); 269 } 270 if (r < 0) { 271 error = ENOENT; 272 break; 273 } 274 275 /* 276 * We support both end-inclusive and 277 * end-exclusive searches. 278 */ 279 if (r == 0 && 280 (cursor->flags & HAMMER_CURSOR_END_INCLUSIVE) == 0) { 281 error = ENOENT; 282 break; 283 } 284 285 switch(elm->leaf.base.btype) { 286 case HAMMER_BTREE_TYPE_RECORD: 287 if ((cursor->flags & HAMMER_CURSOR_ASOF) && 288 hammer_btree_chkts(cursor->asof, &elm->base)) { 289 ++cursor->index; 290 continue; 291 } 292 error = 0; 293 break; 294 default: 295 error = EINVAL; 296 break; 297 } 298 if (error) 299 break; 300 } 301 /* 302 * node pointer invalid after loop 303 */ 304 305 /* 306 * Return entry 307 */ 308 if (hammer_debug_btree) { 309 int i = cursor->index; 310 hammer_btree_elm_t elm = &cursor->node->ondisk->elms[i]; 311 kprintf("ITERATE %p:%d %016llx %02x %016llx lo=%02x\n", 312 cursor->node, i, 313 elm->internal.base.obj_id, 314 elm->internal.base.rec_type, 315 elm->internal.base.key, 316 elm->internal.base.localization 317 ); 318 } 319 return(0); 320 } 321 return(error); 322 } 323 324 /* 325 * We hit an internal element that we could skip as part of a mirroring 326 * scan. Calculate the entire range being skipped. 327 * 328 * It is important to include any gaps between the parent's left_bound 329 * and the node's left_bound, and same goes for the right side. 330 */ 331 static void 332 hammer_cursor_mirror_filter(hammer_cursor_t cursor) 333 { 334 struct hammer_cmirror *cmirror; 335 hammer_node_ondisk_t ondisk; 336 hammer_btree_elm_t elm; 337 338 ondisk = cursor->node->ondisk; 339 cmirror = cursor->cmirror; 340 341 /* 342 * Calculate the skipped range 343 */ 344 elm = &ondisk->elms[cursor->index]; 345 if (cursor->index == 0) 346 cmirror->skip_beg = *cursor->left_bound; 347 else 348 cmirror->skip_beg = elm->internal.base; 349 while (cursor->index < ondisk->count) { 350 if (elm->internal.mirror_tid >= cmirror->mirror_tid) 351 break; 352 ++cursor->index; 353 ++elm; 354 } 355 if (cursor->index == ondisk->count) 356 cmirror->skip_end = *cursor->right_bound; 357 else 358 cmirror->skip_end = elm->internal.base; 359 360 /* 361 * clip the returned result. 362 */ 363 if (hammer_btree_cmp(&cmirror->skip_beg, &cursor->key_beg) < 0) 364 cmirror->skip_beg = cursor->key_beg; 365 if (hammer_btree_cmp(&cmirror->skip_end, &cursor->key_end) > 0) 366 cmirror->skip_end = cursor->key_end; 367 } 368 369 /* 370 * Iterate in the reverse direction. This is used by the pruning code to 371 * avoid overlapping records. 372 */ 373 int 374 hammer_btree_iterate_reverse(hammer_cursor_t cursor) 375 { 376 hammer_node_ondisk_t node; 377 hammer_btree_elm_t elm; 378 int error = 0; 379 int r; 380 int s; 381 382 /* mirror filtering not supported for reverse iteration */ 383 KKASSERT ((cursor->flags & HAMMER_CURSOR_MIRROR_FILTERED) == 0); 384 385 /* 386 * Skip past the current record. For various reasons the cursor 387 * may end up set to -1 or set to point at the end of the current 388 * node. These cases must be addressed. 389 */ 390 node = cursor->node->ondisk; 391 if (node == NULL) 392 return(ENOENT); 393 if (cursor->index != -1 && 394 (cursor->flags & HAMMER_CURSOR_ATEDISK)) { 395 --cursor->index; 396 } 397 if (cursor->index == cursor->node->ondisk->count) 398 --cursor->index; 399 400 /* 401 * Loop until an element is found or we are done. 402 */ 403 for (;;) { 404 ++hammer_stats_btree_iterations; 405 hammer_flusher_clean_loose_ios(cursor->trans->hmp); 406 407 /* 408 * We iterate up the tree and then index over one element 409 * while we are at the last element in the current node. 410 */ 411 if (cursor->index == -1) { 412 error = hammer_cursor_up(cursor); 413 if (error) { 414 cursor->index = 0; /* sanity */ 415 break; 416 } 417 /* reload stale pointer */ 418 node = cursor->node->ondisk; 419 KKASSERT(cursor->index != node->count); 420 --cursor->index; 421 continue; 422 } 423 424 /* 425 * Check internal or leaf element. Determine if the record 426 * at the cursor has gone beyond the end of our range. 427 * 428 * We recurse down through internal nodes. 429 */ 430 KKASSERT(cursor->index != node->count); 431 if (node->type == HAMMER_BTREE_TYPE_INTERNAL) { 432 elm = &node->elms[cursor->index]; 433 r = hammer_btree_cmp(&cursor->key_end, &elm[0].base); 434 s = hammer_btree_cmp(&cursor->key_beg, &elm[1].base); 435 if (hammer_debug_btree) { 436 kprintf("BRACKETL %016llx[%d] %016llx %02x %016llx lo=%02x %d\n", 437 cursor->node->node_offset, 438 cursor->index, 439 elm[0].internal.base.obj_id, 440 elm[0].internal.base.rec_type, 441 elm[0].internal.base.key, 442 elm[0].internal.base.localization, 443 r 444 ); 445 kprintf("BRACKETR %016llx[%d] %016llx %02x %016llx lo=%02x %d\n", 446 cursor->node->node_offset, 447 cursor->index + 1, 448 elm[1].internal.base.obj_id, 449 elm[1].internal.base.rec_type, 450 elm[1].internal.base.key, 451 elm[1].internal.base.localization, 452 s 453 ); 454 } 455 456 if (s >= 0) { 457 error = ENOENT; 458 break; 459 } 460 KKASSERT(r >= 0); 461 462 /* 463 * Better not be zero 464 */ 465 KKASSERT(elm->internal.subtree_offset != 0); 466 467 error = hammer_cursor_down(cursor); 468 if (error) 469 break; 470 KKASSERT(cursor->index == 0); 471 /* reload stale pointer */ 472 node = cursor->node->ondisk; 473 474 /* this can assign -1 if the leaf was empty */ 475 cursor->index = node->count - 1; 476 continue; 477 } else { 478 elm = &node->elms[cursor->index]; 479 s = hammer_btree_cmp(&cursor->key_beg, &elm->base); 480 if (hammer_debug_btree) { 481 kprintf("ELEMENT %016llx:%d %c %016llx %02x %016llx lo=%02x %d\n", 482 cursor->node->node_offset, 483 cursor->index, 484 (elm[0].leaf.base.btype ? 485 elm[0].leaf.base.btype : '?'), 486 elm[0].leaf.base.obj_id, 487 elm[0].leaf.base.rec_type, 488 elm[0].leaf.base.key, 489 elm[0].leaf.base.localization, 490 s 491 ); 492 } 493 if (s > 0) { 494 error = ENOENT; 495 break; 496 } 497 498 switch(elm->leaf.base.btype) { 499 case HAMMER_BTREE_TYPE_RECORD: 500 if ((cursor->flags & HAMMER_CURSOR_ASOF) && 501 hammer_btree_chkts(cursor->asof, &elm->base)) { 502 --cursor->index; 503 continue; 504 } 505 error = 0; 506 break; 507 default: 508 error = EINVAL; 509 break; 510 } 511 if (error) 512 break; 513 } 514 /* 515 * node pointer invalid after loop 516 */ 517 518 /* 519 * Return entry 520 */ 521 if (hammer_debug_btree) { 522 int i = cursor->index; 523 hammer_btree_elm_t elm = &cursor->node->ondisk->elms[i]; 524 kprintf("ITERATE %p:%d %016llx %02x %016llx lo=%02x\n", 525 cursor->node, i, 526 elm->internal.base.obj_id, 527 elm->internal.base.rec_type, 528 elm->internal.base.key, 529 elm->internal.base.localization 530 ); 531 } 532 return(0); 533 } 534 return(error); 535 } 536 537 /* 538 * Lookup cursor->key_beg. 0 is returned on success, ENOENT if the entry 539 * could not be found, EDEADLK if inserting and a retry is needed, and a 540 * fatal error otherwise. When retrying, the caller must terminate the 541 * cursor and reinitialize it. EDEADLK cannot be returned if not inserting. 542 * 543 * The cursor is suitably positioned for a deletion on success, and suitably 544 * positioned for an insertion on ENOENT if HAMMER_CURSOR_INSERT was 545 * specified. 546 * 547 * The cursor may begin anywhere, the search will traverse the tree in 548 * either direction to locate the requested element. 549 * 550 * Most of the logic implementing historical searches is handled here. We 551 * do an initial lookup with create_tid set to the asof TID. Due to the 552 * way records are laid out, a backwards iteration may be required if 553 * ENOENT is returned to locate the historical record. Here's the 554 * problem: 555 * 556 * create_tid: 10 15 20 557 * LEAF1 LEAF2 558 * records: (11) (18) 559 * 560 * Lets say we want to do a lookup AS-OF timestamp 17. We will traverse 561 * LEAF2 but the only record in LEAF2 has a create_tid of 18, which is 562 * not visible and thus causes ENOENT to be returned. We really need 563 * to check record 11 in LEAF1. If it also fails then the search fails 564 * (e.g. it might represent the range 11-16 and thus still not match our 565 * AS-OF timestamp of 17). Note that LEAF1 could be empty, requiring 566 * further iterations. 567 * 568 * If this case occurs btree_search() will set HAMMER_CURSOR_CREATE_CHECK 569 * and the cursor->create_check TID if an iteration might be needed. 570 * In the above example create_check would be set to 14. 571 */ 572 int 573 hammer_btree_lookup(hammer_cursor_t cursor) 574 { 575 int error; 576 577 KKASSERT ((cursor->flags & HAMMER_CURSOR_INSERT) == 0 || 578 cursor->trans->sync_lock_refs > 0); 579 ++hammer_stats_btree_lookups; 580 if (cursor->flags & HAMMER_CURSOR_ASOF) { 581 KKASSERT((cursor->flags & HAMMER_CURSOR_INSERT) == 0); 582 cursor->key_beg.create_tid = cursor->asof; 583 for (;;) { 584 cursor->flags &= ~HAMMER_CURSOR_CREATE_CHECK; 585 error = btree_search(cursor, 0); 586 if (error != ENOENT || 587 (cursor->flags & HAMMER_CURSOR_CREATE_CHECK) == 0) { 588 /* 589 * Stop if no error. 590 * Stop if error other then ENOENT. 591 * Stop if ENOENT and not special case. 592 */ 593 break; 594 } 595 if (hammer_debug_btree) { 596 kprintf("CREATE_CHECK %016llx\n", 597 cursor->create_check); 598 } 599 cursor->key_beg.create_tid = cursor->create_check; 600 /* loop */ 601 } 602 } else { 603 error = btree_search(cursor, 0); 604 } 605 if (error == 0) 606 error = hammer_btree_extract(cursor, cursor->flags); 607 return(error); 608 } 609 610 /* 611 * Execute the logic required to start an iteration. The first record 612 * located within the specified range is returned and iteration control 613 * flags are adjusted for successive hammer_btree_iterate() calls. 614 */ 615 int 616 hammer_btree_first(hammer_cursor_t cursor) 617 { 618 int error; 619 620 error = hammer_btree_lookup(cursor); 621 if (error == ENOENT) { 622 cursor->flags &= ~HAMMER_CURSOR_ATEDISK; 623 error = hammer_btree_iterate(cursor); 624 } 625 cursor->flags |= HAMMER_CURSOR_ATEDISK; 626 return(error); 627 } 628 629 /* 630 * Similarly but for an iteration in the reverse direction. 631 * 632 * Set ATEDISK when iterating backwards to skip the current entry, 633 * which after an ENOENT lookup will be pointing beyond our end point. 634 */ 635 int 636 hammer_btree_last(hammer_cursor_t cursor) 637 { 638 struct hammer_base_elm save; 639 int error; 640 641 save = cursor->key_beg; 642 cursor->key_beg = cursor->key_end; 643 error = hammer_btree_lookup(cursor); 644 cursor->key_beg = save; 645 if (error == ENOENT || 646 (cursor->flags & HAMMER_CURSOR_END_INCLUSIVE) == 0) { 647 cursor->flags |= HAMMER_CURSOR_ATEDISK; 648 error = hammer_btree_iterate_reverse(cursor); 649 } 650 cursor->flags |= HAMMER_CURSOR_ATEDISK; 651 return(error); 652 } 653 654 /* 655 * Extract the record and/or data associated with the cursor's current 656 * position. Any prior record or data stored in the cursor is replaced. 657 * The cursor must be positioned at a leaf node. 658 * 659 * NOTE: All extractions occur at the leaf of the B-Tree. 660 */ 661 int 662 hammer_btree_extract(hammer_cursor_t cursor, int flags) 663 { 664 hammer_node_ondisk_t node; 665 hammer_btree_elm_t elm; 666 hammer_off_t data_off; 667 hammer_mount_t hmp; 668 int32_t data_len; 669 int error; 670 671 /* 672 * The case where the data reference resolves to the same buffer 673 * as the record reference must be handled. 674 */ 675 node = cursor->node->ondisk; 676 elm = &node->elms[cursor->index]; 677 cursor->data = NULL; 678 hmp = cursor->node->hmp; 679 680 /* 681 * There is nothing to extract for an internal element. 682 */ 683 if (node->type == HAMMER_BTREE_TYPE_INTERNAL) 684 return(EINVAL); 685 686 /* 687 * Only record types have data. 688 */ 689 KKASSERT(node->type == HAMMER_BTREE_TYPE_LEAF); 690 cursor->leaf = &elm->leaf; 691 692 if ((flags & HAMMER_CURSOR_GET_DATA) == 0) 693 return(0); 694 if (elm->leaf.base.btype != HAMMER_BTREE_TYPE_RECORD) 695 return(0); 696 data_off = elm->leaf.data_offset; 697 data_len = elm->leaf.data_len; 698 if (data_off == 0) 699 return(0); 700 701 /* 702 * Load the data 703 */ 704 KKASSERT(data_len >= 0 && data_len <= HAMMER_XBUFSIZE); 705 cursor->data = hammer_bread_ext(hmp, data_off, data_len, 706 &error, &cursor->data_buffer); 707 if (hammer_crc_test_leaf(cursor->data, &elm->leaf) == 0) { 708 kprintf("CRC DATA @ %016llx/%d FAILED\n", 709 elm->leaf.data_offset, elm->leaf.data_len); 710 Debugger("CRC FAILED: DATA"); 711 } 712 return(error); 713 } 714 715 716 /* 717 * Insert a leaf element into the B-Tree at the current cursor position. 718 * The cursor is positioned such that the element at and beyond the cursor 719 * are shifted to make room for the new record. 720 * 721 * The caller must call hammer_btree_lookup() with the HAMMER_CURSOR_INSERT 722 * flag set and that call must return ENOENT before this function can be 723 * called. 724 * 725 * The caller may depend on the cursor's exclusive lock after return to 726 * interlock frontend visibility (see HAMMER_RECF_CONVERT_DELETE). 727 * 728 * ENOSPC is returned if there is no room to insert a new record. 729 */ 730 int 731 hammer_btree_insert(hammer_cursor_t cursor, hammer_btree_leaf_elm_t elm, 732 int *doprop) 733 { 734 hammer_node_ondisk_t node; 735 int i; 736 int error; 737 738 *doprop = 0; 739 if ((error = hammer_cursor_upgrade_node(cursor)) != 0) 740 return(error); 741 ++hammer_stats_btree_inserts; 742 743 /* 744 * Insert the element at the leaf node and update the count in the 745 * parent. It is possible for parent to be NULL, indicating that 746 * the filesystem's ROOT B-Tree node is a leaf itself, which is 747 * possible. The root inode can never be deleted so the leaf should 748 * never be empty. 749 * 750 * Remember that the right-hand boundary is not included in the 751 * count. 752 */ 753 hammer_modify_node_all(cursor->trans, cursor->node); 754 node = cursor->node->ondisk; 755 i = cursor->index; 756 KKASSERT(elm->base.btype != 0); 757 KKASSERT(node->type == HAMMER_BTREE_TYPE_LEAF); 758 KKASSERT(node->count < HAMMER_BTREE_LEAF_ELMS); 759 if (i != node->count) { 760 bcopy(&node->elms[i], &node->elms[i+1], 761 (node->count - i) * sizeof(*elm)); 762 } 763 node->elms[i].leaf = *elm; 764 ++node->count; 765 hammer_cursor_inserted_element(cursor->node, i); 766 767 /* 768 * Update the leaf node's aggregate mirror_tid for mirroring 769 * support. 770 */ 771 if (node->mirror_tid < elm->base.delete_tid) { 772 node->mirror_tid = elm->base.delete_tid; 773 *doprop = 1; 774 } 775 if (node->mirror_tid < elm->base.create_tid) { 776 node->mirror_tid = elm->base.create_tid; 777 *doprop = 1; 778 } 779 hammer_modify_node_done(cursor->node); 780 781 /* 782 * Debugging sanity checks. 783 */ 784 KKASSERT(hammer_btree_cmp(cursor->left_bound, &elm->base) <= 0); 785 KKASSERT(hammer_btree_cmp(cursor->right_bound, &elm->base) > 0); 786 if (i) { 787 KKASSERT(hammer_btree_cmp(&node->elms[i-1].leaf.base, &elm->base) < 0); 788 } 789 if (i != node->count - 1) 790 KKASSERT(hammer_btree_cmp(&node->elms[i+1].leaf.base, &elm->base) > 0); 791 792 return(0); 793 } 794 795 /* 796 * Delete a record from the B-Tree at the current cursor position. 797 * The cursor is positioned such that the current element is the one 798 * to be deleted. 799 * 800 * On return the cursor will be positioned after the deleted element and 801 * MAY point to an internal node. It will be suitable for the continuation 802 * of an iteration but not for an insertion or deletion. 803 * 804 * Deletions will attempt to partially rebalance the B-Tree in an upward 805 * direction, but will terminate rather then deadlock. Empty internal nodes 806 * are never allowed by a deletion which deadlocks may end up giving us an 807 * empty leaf. The pruner will clean up and rebalance the tree. 808 * 809 * This function can return EDEADLK, requiring the caller to retry the 810 * operation after clearing the deadlock. 811 */ 812 int 813 hammer_btree_delete(hammer_cursor_t cursor) 814 { 815 hammer_node_ondisk_t ondisk; 816 hammer_node_t node; 817 hammer_node_t parent; 818 int error; 819 int i; 820 821 KKASSERT (cursor->trans->sync_lock_refs > 0); 822 if ((error = hammer_cursor_upgrade(cursor)) != 0) 823 return(error); 824 ++hammer_stats_btree_deletes; 825 826 /* 827 * Delete the element from the leaf node. 828 * 829 * Remember that leaf nodes do not have boundaries. 830 */ 831 node = cursor->node; 832 ondisk = node->ondisk; 833 i = cursor->index; 834 835 KKASSERT(ondisk->type == HAMMER_BTREE_TYPE_LEAF); 836 KKASSERT(i >= 0 && i < ondisk->count); 837 hammer_modify_node_all(cursor->trans, node); 838 if (i + 1 != ondisk->count) { 839 bcopy(&ondisk->elms[i+1], &ondisk->elms[i], 840 (ondisk->count - i - 1) * sizeof(ondisk->elms[0])); 841 } 842 --ondisk->count; 843 hammer_modify_node_done(node); 844 hammer_cursor_deleted_element(node, i); 845 846 /* 847 * Validate local parent 848 */ 849 if (ondisk->parent) { 850 parent = cursor->parent; 851 852 KKASSERT(parent != NULL); 853 KKASSERT(parent->node_offset == ondisk->parent); 854 } 855 856 /* 857 * If the leaf becomes empty it must be detached from the parent, 858 * potentially recursing through to the filesystem root. 859 * 860 * This may reposition the cursor at one of the parent's of the 861 * current node. 862 * 863 * Ignore deadlock errors, that simply means that btree_remove 864 * was unable to recurse and had to leave us with an empty leaf. 865 */ 866 KKASSERT(cursor->index <= ondisk->count); 867 if (ondisk->count == 0) { 868 error = btree_remove(cursor); 869 if (error == EDEADLK) 870 error = 0; 871 } else { 872 error = 0; 873 } 874 KKASSERT(cursor->parent == NULL || 875 cursor->parent_index < cursor->parent->ondisk->count); 876 return(error); 877 } 878 879 /* 880 * PRIMAY B-TREE SEARCH SUPPORT PROCEDURE 881 * 882 * Search the filesystem B-Tree for cursor->key_beg, return the matching node. 883 * 884 * The search can begin ANYWHERE in the B-Tree. As a first step the search 885 * iterates up the tree as necessary to properly position itself prior to 886 * actually doing the sarch. 887 * 888 * INSERTIONS: The search will split full nodes and leaves on its way down 889 * and guarentee that the leaf it ends up on is not full. If we run out 890 * of space the search continues to the leaf (to position the cursor for 891 * the spike), but ENOSPC is returned. 892 * 893 * The search is only guarenteed to end up on a leaf if an error code of 0 894 * is returned, or if inserting and an error code of ENOENT is returned. 895 * Otherwise it can stop at an internal node. On success a search returns 896 * a leaf node. 897 * 898 * COMPLEXITY WARNING! This is the core B-Tree search code for the entire 899 * filesystem, and it is not simple code. Please note the following facts: 900 * 901 * - Internal node recursions have a boundary on the left AND right. The 902 * right boundary is non-inclusive. The create_tid is a generic part 903 * of the key for internal nodes. 904 * 905 * - Leaf nodes contain terminal elements only now. 906 * 907 * - Filesystem lookups typically set HAMMER_CURSOR_ASOF, indicating a 908 * historical search. ASOF and INSERT are mutually exclusive. When 909 * doing an as-of lookup btree_search() checks for a right-edge boundary 910 * case. If while recursing down the left-edge differs from the key 911 * by ONLY its create_tid, HAMMER_CURSOR_CREATE_CHECK is set along 912 * with cursor->create_check. This is used by btree_lookup() to iterate. 913 * The iteration backwards because as-of searches can wind up going 914 * down the wrong branch of the B-Tree. 915 */ 916 static 917 int 918 btree_search(hammer_cursor_t cursor, int flags) 919 { 920 hammer_node_ondisk_t node; 921 hammer_btree_elm_t elm; 922 int error; 923 int enospc = 0; 924 int i; 925 int r; 926 int s; 927 928 flags |= cursor->flags; 929 ++hammer_stats_btree_searches; 930 931 if (hammer_debug_btree) { 932 kprintf("SEARCH %016llx[%d] %016llx %02x key=%016llx cre=%016llx lo=%02x (td = %p)\n", 933 cursor->node->node_offset, 934 cursor->index, 935 cursor->key_beg.obj_id, 936 cursor->key_beg.rec_type, 937 cursor->key_beg.key, 938 cursor->key_beg.create_tid, 939 cursor->key_beg.localization, 940 curthread 941 ); 942 if (cursor->parent) 943 kprintf("SEARCHP %016llx[%d] (%016llx/%016llx %016llx/%016llx) (%p/%p %p/%p)\n", 944 cursor->parent->node_offset, cursor->parent_index, 945 cursor->left_bound->obj_id, 946 cursor->parent->ondisk->elms[cursor->parent_index].internal.base.obj_id, 947 cursor->right_bound->obj_id, 948 cursor->parent->ondisk->elms[cursor->parent_index+1].internal.base.obj_id, 949 cursor->left_bound, 950 &cursor->parent->ondisk->elms[cursor->parent_index], 951 cursor->right_bound, 952 &cursor->parent->ondisk->elms[cursor->parent_index+1] 953 ); 954 } 955 956 /* 957 * Move our cursor up the tree until we find a node whos range covers 958 * the key we are trying to locate. 959 * 960 * The left bound is inclusive, the right bound is non-inclusive. 961 * It is ok to cursor up too far. 962 */ 963 for (;;) { 964 r = hammer_btree_cmp(&cursor->key_beg, cursor->left_bound); 965 s = hammer_btree_cmp(&cursor->key_beg, cursor->right_bound); 966 if (r >= 0 && s < 0) 967 break; 968 KKASSERT(cursor->parent); 969 ++hammer_stats_btree_iterations; 970 error = hammer_cursor_up(cursor); 971 if (error) 972 goto done; 973 } 974 975 /* 976 * The delete-checks below are based on node, not parent. Set the 977 * initial delete-check based on the parent. 978 */ 979 if (r == 1) { 980 KKASSERT(cursor->left_bound->create_tid != 1); 981 cursor->create_check = cursor->left_bound->create_tid - 1; 982 cursor->flags |= HAMMER_CURSOR_CREATE_CHECK; 983 } 984 985 /* 986 * We better have ended up with a node somewhere. 987 */ 988 KKASSERT(cursor->node != NULL); 989 990 /* 991 * If we are inserting we can't start at a full node if the parent 992 * is also full (because there is no way to split the node), 993 * continue running up the tree until the requirement is satisfied 994 * or we hit the root of the filesystem. 995 * 996 * (If inserting we aren't doing an as-of search so we don't have 997 * to worry about create_check). 998 */ 999 while ((flags & HAMMER_CURSOR_INSERT) && enospc == 0) { 1000 if (cursor->node->ondisk->type == HAMMER_BTREE_TYPE_INTERNAL) { 1001 if (btree_node_is_full(cursor->node->ondisk) == 0) 1002 break; 1003 } else { 1004 if (btree_node_is_full(cursor->node->ondisk) ==0) 1005 break; 1006 } 1007 if (cursor->node->ondisk->parent == 0 || 1008 cursor->parent->ondisk->count != HAMMER_BTREE_INT_ELMS) { 1009 break; 1010 } 1011 ++hammer_stats_btree_iterations; 1012 error = hammer_cursor_up(cursor); 1013 /* node may have become stale */ 1014 if (error) 1015 goto done; 1016 } 1017 1018 /* 1019 * Push down through internal nodes to locate the requested key. 1020 */ 1021 node = cursor->node->ondisk; 1022 while (node->type == HAMMER_BTREE_TYPE_INTERNAL) { 1023 /* 1024 * Scan the node to find the subtree index to push down into. 1025 * We go one-past, then back-up. 1026 * 1027 * We must proactively remove deleted elements which may 1028 * have been left over from a deadlocked btree_remove(). 1029 * 1030 * The left and right boundaries are included in the loop 1031 * in order to detect edge cases. 1032 * 1033 * If the separator only differs by create_tid (r == 1) 1034 * and we are doing an as-of search, we may end up going 1035 * down a branch to the left of the one containing the 1036 * desired key. This requires numerous special cases. 1037 */ 1038 ++hammer_stats_btree_iterations; 1039 if (hammer_debug_btree) { 1040 kprintf("SEARCH-I %016llx count=%d\n", 1041 cursor->node->node_offset, 1042 node->count); 1043 } 1044 1045 /* 1046 * Try to shortcut the search before dropping into the 1047 * linear loop. Locate the first node where r <= 1. 1048 */ 1049 i = hammer_btree_search_node(&cursor->key_beg, node); 1050 while (i <= node->count) { 1051 ++hammer_stats_btree_elements; 1052 elm = &node->elms[i]; 1053 r = hammer_btree_cmp(&cursor->key_beg, &elm->base); 1054 if (hammer_debug_btree > 2) { 1055 kprintf(" IELM %p %d r=%d\n", 1056 &node->elms[i], i, r); 1057 } 1058 if (r < 0) 1059 break; 1060 if (r == 1) { 1061 KKASSERT(elm->base.create_tid != 1); 1062 cursor->create_check = elm->base.create_tid - 1; 1063 cursor->flags |= HAMMER_CURSOR_CREATE_CHECK; 1064 } 1065 ++i; 1066 } 1067 if (hammer_debug_btree) { 1068 kprintf("SEARCH-I preI=%d/%d r=%d\n", 1069 i, node->count, r); 1070 } 1071 1072 /* 1073 * These cases occur when the parent's idea of the boundary 1074 * is wider then the child's idea of the boundary, and 1075 * require special handling. If not inserting we can 1076 * terminate the search early for these cases but the 1077 * child's boundaries cannot be unconditionally modified. 1078 */ 1079 if (i == 0) { 1080 /* 1081 * If i == 0 the search terminated to the LEFT of the 1082 * left_boundary but to the RIGHT of the parent's left 1083 * boundary. 1084 */ 1085 u_int8_t save; 1086 1087 elm = &node->elms[0]; 1088 1089 /* 1090 * If we aren't inserting we can stop here. 1091 */ 1092 if ((flags & (HAMMER_CURSOR_INSERT | 1093 HAMMER_CURSOR_PRUNING)) == 0) { 1094 cursor->index = 0; 1095 return(ENOENT); 1096 } 1097 1098 /* 1099 * Correct a left-hand boundary mismatch. 1100 * 1101 * We can only do this if we can upgrade the lock, 1102 * and synchronized as a background cursor (i.e. 1103 * inserting or pruning). 1104 * 1105 * WARNING: We can only do this if inserting, i.e. 1106 * we are running on the backend. 1107 */ 1108 if ((error = hammer_cursor_upgrade(cursor)) != 0) 1109 return(error); 1110 KKASSERT(cursor->flags & HAMMER_CURSOR_BACKEND); 1111 hammer_modify_node_field(cursor->trans, cursor->node, 1112 elms[0]); 1113 save = node->elms[0].base.btype; 1114 node->elms[0].base = *cursor->left_bound; 1115 node->elms[0].base.btype = save; 1116 hammer_modify_node_done(cursor->node); 1117 } else if (i == node->count + 1) { 1118 /* 1119 * If i == node->count + 1 the search terminated to 1120 * the RIGHT of the right boundary but to the LEFT 1121 * of the parent's right boundary. If we aren't 1122 * inserting we can stop here. 1123 * 1124 * Note that the last element in this case is 1125 * elms[i-2] prior to adjustments to 'i'. 1126 */ 1127 --i; 1128 if ((flags & (HAMMER_CURSOR_INSERT | 1129 HAMMER_CURSOR_PRUNING)) == 0) { 1130 cursor->index = i; 1131 return (ENOENT); 1132 } 1133 1134 /* 1135 * Correct a right-hand boundary mismatch. 1136 * (actual push-down record is i-2 prior to 1137 * adjustments to i). 1138 * 1139 * We can only do this if we can upgrade the lock, 1140 * and synchronized as a background cursor (i.e. 1141 * inserting or pruning). 1142 * 1143 * WARNING: We can only do this if inserting, i.e. 1144 * we are running on the backend. 1145 */ 1146 if ((error = hammer_cursor_upgrade(cursor)) != 0) 1147 return(error); 1148 elm = &node->elms[i]; 1149 KKASSERT(cursor->flags & HAMMER_CURSOR_BACKEND); 1150 hammer_modify_node(cursor->trans, cursor->node, 1151 &elm->base, sizeof(elm->base)); 1152 elm->base = *cursor->right_bound; 1153 hammer_modify_node_done(cursor->node); 1154 --i; 1155 } else { 1156 /* 1157 * The push-down index is now i - 1. If we had 1158 * terminated on the right boundary this will point 1159 * us at the last element. 1160 */ 1161 --i; 1162 } 1163 cursor->index = i; 1164 elm = &node->elms[i]; 1165 1166 if (hammer_debug_btree) { 1167 kprintf("RESULT-I %016llx[%d] %016llx %02x " 1168 "key=%016llx cre=%016llx lo=%02x\n", 1169 cursor->node->node_offset, 1170 i, 1171 elm->internal.base.obj_id, 1172 elm->internal.base.rec_type, 1173 elm->internal.base.key, 1174 elm->internal.base.create_tid, 1175 elm->internal.base.localization 1176 ); 1177 } 1178 1179 /* 1180 * We better have a valid subtree offset. 1181 */ 1182 KKASSERT(elm->internal.subtree_offset != 0); 1183 1184 /* 1185 * Handle insertion and deletion requirements. 1186 * 1187 * If inserting split full nodes. The split code will 1188 * adjust cursor->node and cursor->index if the current 1189 * index winds up in the new node. 1190 * 1191 * If inserting and a left or right edge case was detected, 1192 * we cannot correct the left or right boundary and must 1193 * prepend and append an empty leaf node in order to make 1194 * the boundary correction. 1195 * 1196 * If we run out of space we set enospc and continue on 1197 * to a leaf to provide the spike code with a good point 1198 * of entry. 1199 */ 1200 if ((flags & HAMMER_CURSOR_INSERT) && enospc == 0) { 1201 if (btree_node_is_full(node)) { 1202 error = btree_split_internal(cursor); 1203 if (error) { 1204 if (error != ENOSPC) 1205 goto done; 1206 enospc = 1; 1207 } 1208 /* 1209 * reload stale pointers 1210 */ 1211 i = cursor->index; 1212 node = cursor->node->ondisk; 1213 } 1214 } 1215 1216 /* 1217 * Push down (push into new node, existing node becomes 1218 * the parent) and continue the search. 1219 */ 1220 error = hammer_cursor_down(cursor); 1221 /* node may have become stale */ 1222 if (error) 1223 goto done; 1224 node = cursor->node->ondisk; 1225 } 1226 1227 /* 1228 * We are at a leaf, do a linear search of the key array. 1229 * 1230 * On success the index is set to the matching element and 0 1231 * is returned. 1232 * 1233 * On failure the index is set to the insertion point and ENOENT 1234 * is returned. 1235 * 1236 * Boundaries are not stored in leaf nodes, so the index can wind 1237 * up to the left of element 0 (index == 0) or past the end of 1238 * the array (index == node->count). It is also possible that the 1239 * leaf might be empty. 1240 */ 1241 ++hammer_stats_btree_iterations; 1242 KKASSERT (node->type == HAMMER_BTREE_TYPE_LEAF); 1243 KKASSERT(node->count <= HAMMER_BTREE_LEAF_ELMS); 1244 if (hammer_debug_btree) { 1245 kprintf("SEARCH-L %016llx count=%d\n", 1246 cursor->node->node_offset, 1247 node->count); 1248 } 1249 1250 /* 1251 * Try to shortcut the search before dropping into the 1252 * linear loop. Locate the first node where r <= 1. 1253 */ 1254 i = hammer_btree_search_node(&cursor->key_beg, node); 1255 while (i < node->count) { 1256 ++hammer_stats_btree_elements; 1257 elm = &node->elms[i]; 1258 1259 r = hammer_btree_cmp(&cursor->key_beg, &elm->leaf.base); 1260 1261 if (hammer_debug_btree > 1) 1262 kprintf(" ELM %p %d r=%d\n", &node->elms[i], i, r); 1263 1264 /* 1265 * We are at a record element. Stop if we've flipped past 1266 * key_beg, not counting the create_tid test. Allow the 1267 * r == 1 case (key_beg > element but differs only by its 1268 * create_tid) to fall through to the AS-OF check. 1269 */ 1270 KKASSERT (elm->leaf.base.btype == HAMMER_BTREE_TYPE_RECORD); 1271 1272 if (r < 0) 1273 goto failed; 1274 if (r > 1) { 1275 ++i; 1276 continue; 1277 } 1278 1279 /* 1280 * Check our as-of timestamp against the element. 1281 */ 1282 if (flags & HAMMER_CURSOR_ASOF) { 1283 if (hammer_btree_chkts(cursor->asof, 1284 &node->elms[i].base) != 0) { 1285 ++i; 1286 continue; 1287 } 1288 /* success */ 1289 } else { 1290 if (r > 0) { /* can only be +1 */ 1291 ++i; 1292 continue; 1293 } 1294 /* success */ 1295 } 1296 cursor->index = i; 1297 error = 0; 1298 if (hammer_debug_btree) { 1299 kprintf("RESULT-L %016llx[%d] (SUCCESS)\n", 1300 cursor->node->node_offset, i); 1301 } 1302 goto done; 1303 } 1304 1305 /* 1306 * The search of the leaf node failed. i is the insertion point. 1307 */ 1308 failed: 1309 if (hammer_debug_btree) { 1310 kprintf("RESULT-L %016llx[%d] (FAILED)\n", 1311 cursor->node->node_offset, i); 1312 } 1313 1314 /* 1315 * No exact match was found, i is now at the insertion point. 1316 * 1317 * If inserting split a full leaf before returning. This 1318 * may have the side effect of adjusting cursor->node and 1319 * cursor->index. 1320 */ 1321 cursor->index = i; 1322 if ((flags & HAMMER_CURSOR_INSERT) && enospc == 0 && 1323 btree_node_is_full(node)) { 1324 error = btree_split_leaf(cursor); 1325 if (error) { 1326 if (error != ENOSPC) 1327 goto done; 1328 enospc = 1; 1329 } 1330 /* 1331 * reload stale pointers 1332 */ 1333 /* NOT USED 1334 i = cursor->index; 1335 node = &cursor->node->internal; 1336 */ 1337 } 1338 1339 /* 1340 * We reached a leaf but did not find the key we were looking for. 1341 * If this is an insert we will be properly positioned for an insert 1342 * (ENOENT) or spike (ENOSPC) operation. 1343 */ 1344 error = enospc ? ENOSPC : ENOENT; 1345 done: 1346 return(error); 1347 } 1348 1349 /* 1350 * Heuristical search for the first element whos comparison is <= 1. May 1351 * return an index whos compare result is > 1 but may only return an index 1352 * whos compare result is <= 1 if it is the first element with that result. 1353 */ 1354 int 1355 hammer_btree_search_node(hammer_base_elm_t elm, hammer_node_ondisk_t node) 1356 { 1357 int b; 1358 int s; 1359 int i; 1360 int r; 1361 1362 /* 1363 * Don't bother if the node does not have very many elements 1364 */ 1365 b = 0; 1366 s = node->count; 1367 while (s - b > 4) { 1368 i = b + (s - b) / 2; 1369 ++hammer_stats_btree_elements; 1370 r = hammer_btree_cmp(elm, &node->elms[i].leaf.base); 1371 if (r <= 1) { 1372 s = i; 1373 } else { 1374 b = i; 1375 } 1376 } 1377 return(b); 1378 } 1379 1380 1381 /************************************************************************ 1382 * SPLITTING AND MERGING * 1383 ************************************************************************ 1384 * 1385 * These routines do all the dirty work required to split and merge nodes. 1386 */ 1387 1388 /* 1389 * Split an internal node into two nodes and move the separator at the split 1390 * point to the parent. 1391 * 1392 * (cursor->node, cursor->index) indicates the element the caller intends 1393 * to push into. We will adjust node and index if that element winds 1394 * up in the split node. 1395 * 1396 * If we are at the root of the filesystem a new root must be created with 1397 * two elements, one pointing to the original root and one pointing to the 1398 * newly allocated split node. 1399 */ 1400 static 1401 int 1402 btree_split_internal(hammer_cursor_t cursor) 1403 { 1404 hammer_node_ondisk_t ondisk; 1405 hammer_node_t node; 1406 hammer_node_t parent; 1407 hammer_node_t new_node; 1408 hammer_btree_elm_t elm; 1409 hammer_btree_elm_t parent_elm; 1410 hammer_node_locklist_t locklist = NULL; 1411 hammer_mount_t hmp = cursor->trans->hmp; 1412 int parent_index; 1413 int made_root; 1414 int split; 1415 int error; 1416 int i; 1417 const int esize = sizeof(*elm); 1418 1419 error = hammer_btree_lock_children(cursor, &locklist); 1420 if (error) 1421 goto done; 1422 if ((error = hammer_cursor_upgrade(cursor)) != 0) 1423 goto done; 1424 ++hammer_stats_btree_splits; 1425 1426 /* 1427 * We are splitting but elms[split] will be promoted to the parent, 1428 * leaving the right hand node with one less element. If the 1429 * insertion point will be on the left-hand side adjust the split 1430 * point to give the right hand side one additional node. 1431 */ 1432 node = cursor->node; 1433 ondisk = node->ondisk; 1434 split = (ondisk->count + 1) / 2; 1435 if (cursor->index <= split) 1436 --split; 1437 1438 /* 1439 * If we are at the root of the filesystem, create a new root node 1440 * with 1 element and split normally. Avoid making major 1441 * modifications until we know the whole operation will work. 1442 */ 1443 if (ondisk->parent == 0) { 1444 parent = hammer_alloc_btree(cursor->trans, &error); 1445 if (parent == NULL) 1446 goto done; 1447 hammer_lock_ex(&parent->lock); 1448 hammer_modify_node_noundo(cursor->trans, parent); 1449 ondisk = parent->ondisk; 1450 ondisk->count = 1; 1451 ondisk->parent = 0; 1452 ondisk->mirror_tid = node->ondisk->mirror_tid; 1453 ondisk->type = HAMMER_BTREE_TYPE_INTERNAL; 1454 ondisk->elms[0].base = hmp->root_btree_beg; 1455 ondisk->elms[0].base.btype = node->ondisk->type; 1456 ondisk->elms[0].internal.subtree_offset = node->node_offset; 1457 ondisk->elms[1].base = hmp->root_btree_end; 1458 hammer_modify_node_done(parent); 1459 /* ondisk->elms[1].base.btype - not used */ 1460 made_root = 1; 1461 parent_index = 0; /* index of current node in parent */ 1462 } else { 1463 made_root = 0; 1464 parent = cursor->parent; 1465 parent_index = cursor->parent_index; 1466 } 1467 1468 /* 1469 * Split node into new_node at the split point. 1470 * 1471 * B O O O P N N B <-- P = node->elms[split] 1472 * 0 1 2 3 4 5 6 <-- subtree indices 1473 * 1474 * x x P x x 1475 * s S S s 1476 * / \ 1477 * B O O O B B N N B <--- inner boundary points are 'P' 1478 * 0 1 2 3 4 5 6 1479 * 1480 */ 1481 new_node = hammer_alloc_btree(cursor->trans, &error); 1482 if (new_node == NULL) { 1483 if (made_root) { 1484 hammer_unlock(&parent->lock); 1485 hammer_delete_node(cursor->trans, parent); 1486 hammer_rel_node(parent); 1487 } 1488 goto done; 1489 } 1490 hammer_lock_ex(&new_node->lock); 1491 1492 /* 1493 * Create the new node. P becomes the left-hand boundary in the 1494 * new node. Copy the right-hand boundary as well. 1495 * 1496 * elm is the new separator. 1497 */ 1498 hammer_modify_node_noundo(cursor->trans, new_node); 1499 hammer_modify_node_all(cursor->trans, node); 1500 ondisk = node->ondisk; 1501 elm = &ondisk->elms[split]; 1502 bcopy(elm, &new_node->ondisk->elms[0], 1503 (ondisk->count - split + 1) * esize); 1504 new_node->ondisk->count = ondisk->count - split; 1505 new_node->ondisk->parent = parent->node_offset; 1506 new_node->ondisk->type = HAMMER_BTREE_TYPE_INTERNAL; 1507 new_node->ondisk->mirror_tid = ondisk->mirror_tid; 1508 KKASSERT(ondisk->type == new_node->ondisk->type); 1509 hammer_cursor_split_node(node, new_node, split); 1510 1511 /* 1512 * Cleanup the original node. Elm (P) becomes the new boundary, 1513 * its subtree_offset was moved to the new node. If we had created 1514 * a new root its parent pointer may have changed. 1515 */ 1516 elm->internal.subtree_offset = 0; 1517 ondisk->count = split; 1518 1519 /* 1520 * Insert the separator into the parent, fixup the parent's 1521 * reference to the original node, and reference the new node. 1522 * The separator is P. 1523 * 1524 * Remember that base.count does not include the right-hand boundary. 1525 */ 1526 hammer_modify_node_all(cursor->trans, parent); 1527 ondisk = parent->ondisk; 1528 KKASSERT(ondisk->count != HAMMER_BTREE_INT_ELMS); 1529 parent_elm = &ondisk->elms[parent_index+1]; 1530 bcopy(parent_elm, parent_elm + 1, 1531 (ondisk->count - parent_index) * esize); 1532 parent_elm->internal.base = elm->base; /* separator P */ 1533 parent_elm->internal.base.btype = new_node->ondisk->type; 1534 parent_elm->internal.subtree_offset = new_node->node_offset; 1535 parent_elm->internal.mirror_tid = new_node->ondisk->mirror_tid; 1536 ++ondisk->count; 1537 hammer_modify_node_done(parent); 1538 hammer_cursor_inserted_element(parent, parent_index + 1); 1539 1540 /* 1541 * The children of new_node need their parent pointer set to new_node. 1542 * The children have already been locked by 1543 * hammer_btree_lock_children(). 1544 */ 1545 for (i = 0; i < new_node->ondisk->count; ++i) { 1546 elm = &new_node->ondisk->elms[i]; 1547 error = btree_set_parent(cursor->trans, new_node, elm); 1548 if (error) { 1549 panic("btree_split_internal: btree-fixup problem"); 1550 } 1551 } 1552 hammer_modify_node_done(new_node); 1553 1554 /* 1555 * The filesystem's root B-Tree pointer may have to be updated. 1556 */ 1557 if (made_root) { 1558 hammer_volume_t volume; 1559 1560 volume = hammer_get_root_volume(hmp, &error); 1561 KKASSERT(error == 0); 1562 1563 hammer_modify_volume_field(cursor->trans, volume, 1564 vol0_btree_root); 1565 volume->ondisk->vol0_btree_root = parent->node_offset; 1566 hammer_modify_volume_done(volume); 1567 node->ondisk->parent = parent->node_offset; 1568 if (cursor->parent) { 1569 hammer_unlock(&cursor->parent->lock); 1570 hammer_rel_node(cursor->parent); 1571 } 1572 cursor->parent = parent; /* lock'd and ref'd */ 1573 hammer_rel_volume(volume, 0); 1574 } 1575 hammer_modify_node_done(node); 1576 1577 /* 1578 * Ok, now adjust the cursor depending on which element the original 1579 * index was pointing at. If we are >= the split point the push node 1580 * is now in the new node. 1581 * 1582 * NOTE: If we are at the split point itself we cannot stay with the 1583 * original node because the push index will point at the right-hand 1584 * boundary, which is illegal. 1585 * 1586 * NOTE: The cursor's parent or parent_index must be adjusted for 1587 * the case where a new parent (new root) was created, and the case 1588 * where the cursor is now pointing at the split node. 1589 */ 1590 if (cursor->index >= split) { 1591 cursor->parent_index = parent_index + 1; 1592 cursor->index -= split; 1593 hammer_unlock(&cursor->node->lock); 1594 hammer_rel_node(cursor->node); 1595 cursor->node = new_node; /* locked and ref'd */ 1596 } else { 1597 cursor->parent_index = parent_index; 1598 hammer_unlock(&new_node->lock); 1599 hammer_rel_node(new_node); 1600 } 1601 1602 /* 1603 * Fixup left and right bounds 1604 */ 1605 parent_elm = &parent->ondisk->elms[cursor->parent_index]; 1606 cursor->left_bound = &parent_elm[0].internal.base; 1607 cursor->right_bound = &parent_elm[1].internal.base; 1608 KKASSERT(hammer_btree_cmp(cursor->left_bound, 1609 &cursor->node->ondisk->elms[0].internal.base) <= 0); 1610 KKASSERT(hammer_btree_cmp(cursor->right_bound, 1611 &cursor->node->ondisk->elms[cursor->node->ondisk->count].internal.base) >= 0); 1612 1613 done: 1614 hammer_btree_unlock_children(cursor, &locklist); 1615 hammer_cursor_downgrade(cursor); 1616 return (error); 1617 } 1618 1619 /* 1620 * Same as the above, but splits a full leaf node. 1621 * 1622 * This function 1623 */ 1624 static 1625 int 1626 btree_split_leaf(hammer_cursor_t cursor) 1627 { 1628 hammer_node_ondisk_t ondisk; 1629 hammer_node_t parent; 1630 hammer_node_t leaf; 1631 hammer_mount_t hmp; 1632 hammer_node_t new_leaf; 1633 hammer_btree_elm_t elm; 1634 hammer_btree_elm_t parent_elm; 1635 hammer_base_elm_t mid_boundary; 1636 int parent_index; 1637 int made_root; 1638 int split; 1639 int error; 1640 const size_t esize = sizeof(*elm); 1641 1642 if ((error = hammer_cursor_upgrade(cursor)) != 0) 1643 return(error); 1644 ++hammer_stats_btree_splits; 1645 1646 KKASSERT(hammer_btree_cmp(cursor->left_bound, 1647 &cursor->node->ondisk->elms[0].leaf.base) <= 0); 1648 KKASSERT(hammer_btree_cmp(cursor->right_bound, 1649 &cursor->node->ondisk->elms[cursor->node->ondisk->count-1].leaf.base) > 0); 1650 1651 /* 1652 * Calculate the split point. If the insertion point will be on 1653 * the left-hand side adjust the split point to give the right 1654 * hand side one additional node. 1655 * 1656 * Spikes are made up of two leaf elements which cannot be 1657 * safely split. 1658 */ 1659 leaf = cursor->node; 1660 ondisk = leaf->ondisk; 1661 split = (ondisk->count + 1) / 2; 1662 if (cursor->index <= split) 1663 --split; 1664 error = 0; 1665 hmp = leaf->hmp; 1666 1667 elm = &ondisk->elms[split]; 1668 1669 KKASSERT(hammer_btree_cmp(cursor->left_bound, &elm[-1].leaf.base) <= 0); 1670 KKASSERT(hammer_btree_cmp(cursor->left_bound, &elm->leaf.base) <= 0); 1671 KKASSERT(hammer_btree_cmp(cursor->right_bound, &elm->leaf.base) > 0); 1672 KKASSERT(hammer_btree_cmp(cursor->right_bound, &elm[1].leaf.base) > 0); 1673 1674 /* 1675 * If we are at the root of the tree, create a new root node with 1676 * 1 element and split normally. Avoid making major modifications 1677 * until we know the whole operation will work. 1678 */ 1679 if (ondisk->parent == 0) { 1680 parent = hammer_alloc_btree(cursor->trans, &error); 1681 if (parent == NULL) 1682 goto done; 1683 hammer_lock_ex(&parent->lock); 1684 hammer_modify_node_noundo(cursor->trans, parent); 1685 ondisk = parent->ondisk; 1686 ondisk->count = 1; 1687 ondisk->parent = 0; 1688 ondisk->mirror_tid = leaf->ondisk->mirror_tid; 1689 ondisk->type = HAMMER_BTREE_TYPE_INTERNAL; 1690 ondisk->elms[0].base = hmp->root_btree_beg; 1691 ondisk->elms[0].base.btype = leaf->ondisk->type; 1692 ondisk->elms[0].internal.subtree_offset = leaf->node_offset; 1693 ondisk->elms[1].base = hmp->root_btree_end; 1694 /* ondisk->elms[1].base.btype = not used */ 1695 hammer_modify_node_done(parent); 1696 made_root = 1; 1697 parent_index = 0; /* insertion point in parent */ 1698 } else { 1699 made_root = 0; 1700 parent = cursor->parent; 1701 parent_index = cursor->parent_index; 1702 } 1703 1704 /* 1705 * Split leaf into new_leaf at the split point. Select a separator 1706 * value in-between the two leafs but with a bent towards the right 1707 * leaf since comparisons use an 'elm >= separator' inequality. 1708 * 1709 * L L L L L L L L 1710 * 1711 * x x P x x 1712 * s S S s 1713 * / \ 1714 * L L L L L L L L 1715 */ 1716 new_leaf = hammer_alloc_btree(cursor->trans, &error); 1717 if (new_leaf == NULL) { 1718 if (made_root) { 1719 hammer_unlock(&parent->lock); 1720 hammer_delete_node(cursor->trans, parent); 1721 hammer_rel_node(parent); 1722 } 1723 goto done; 1724 } 1725 hammer_lock_ex(&new_leaf->lock); 1726 1727 /* 1728 * Create the new node and copy the leaf elements from the split 1729 * point on to the new node. 1730 */ 1731 hammer_modify_node_all(cursor->trans, leaf); 1732 hammer_modify_node_noundo(cursor->trans, new_leaf); 1733 ondisk = leaf->ondisk; 1734 elm = &ondisk->elms[split]; 1735 bcopy(elm, &new_leaf->ondisk->elms[0], (ondisk->count - split) * esize); 1736 new_leaf->ondisk->count = ondisk->count - split; 1737 new_leaf->ondisk->parent = parent->node_offset; 1738 new_leaf->ondisk->type = HAMMER_BTREE_TYPE_LEAF; 1739 new_leaf->ondisk->mirror_tid = ondisk->mirror_tid; 1740 KKASSERT(ondisk->type == new_leaf->ondisk->type); 1741 hammer_modify_node_done(new_leaf); 1742 hammer_cursor_split_node(leaf, new_leaf, split); 1743 1744 /* 1745 * Cleanup the original node. Because this is a leaf node and 1746 * leaf nodes do not have a right-hand boundary, there 1747 * aren't any special edge cases to clean up. We just fixup the 1748 * count. 1749 */ 1750 ondisk->count = split; 1751 1752 /* 1753 * Insert the separator into the parent, fixup the parent's 1754 * reference to the original node, and reference the new node. 1755 * The separator is P. 1756 * 1757 * Remember that base.count does not include the right-hand boundary. 1758 * We are copying parent_index+1 to parent_index+2, not +0 to +1. 1759 */ 1760 hammer_modify_node_all(cursor->trans, parent); 1761 ondisk = parent->ondisk; 1762 KKASSERT(split != 0); 1763 KKASSERT(ondisk->count != HAMMER_BTREE_INT_ELMS); 1764 parent_elm = &ondisk->elms[parent_index+1]; 1765 bcopy(parent_elm, parent_elm + 1, 1766 (ondisk->count - parent_index) * esize); 1767 1768 hammer_make_separator(&elm[-1].base, &elm[0].base, &parent_elm->base); 1769 parent_elm->internal.base.btype = new_leaf->ondisk->type; 1770 parent_elm->internal.subtree_offset = new_leaf->node_offset; 1771 parent_elm->internal.mirror_tid = new_leaf->ondisk->mirror_tid; 1772 mid_boundary = &parent_elm->base; 1773 ++ondisk->count; 1774 hammer_modify_node_done(parent); 1775 hammer_cursor_inserted_element(parent, parent_index + 1); 1776 1777 /* 1778 * The filesystem's root B-Tree pointer may have to be updated. 1779 */ 1780 if (made_root) { 1781 hammer_volume_t volume; 1782 1783 volume = hammer_get_root_volume(hmp, &error); 1784 KKASSERT(error == 0); 1785 1786 hammer_modify_volume_field(cursor->trans, volume, 1787 vol0_btree_root); 1788 volume->ondisk->vol0_btree_root = parent->node_offset; 1789 hammer_modify_volume_done(volume); 1790 leaf->ondisk->parent = parent->node_offset; 1791 if (cursor->parent) { 1792 hammer_unlock(&cursor->parent->lock); 1793 hammer_rel_node(cursor->parent); 1794 } 1795 cursor->parent = parent; /* lock'd and ref'd */ 1796 hammer_rel_volume(volume, 0); 1797 } 1798 hammer_modify_node_done(leaf); 1799 1800 /* 1801 * Ok, now adjust the cursor depending on which element the original 1802 * index was pointing at. If we are >= the split point the push node 1803 * is now in the new node. 1804 * 1805 * NOTE: If we are at the split point itself we need to select the 1806 * old or new node based on where key_beg's insertion point will be. 1807 * If we pick the wrong side the inserted element will wind up in 1808 * the wrong leaf node and outside that node's bounds. 1809 */ 1810 if (cursor->index > split || 1811 (cursor->index == split && 1812 hammer_btree_cmp(&cursor->key_beg, mid_boundary) >= 0)) { 1813 cursor->parent_index = parent_index + 1; 1814 cursor->index -= split; 1815 hammer_unlock(&cursor->node->lock); 1816 hammer_rel_node(cursor->node); 1817 cursor->node = new_leaf; 1818 } else { 1819 cursor->parent_index = parent_index; 1820 hammer_unlock(&new_leaf->lock); 1821 hammer_rel_node(new_leaf); 1822 } 1823 1824 /* 1825 * Fixup left and right bounds 1826 */ 1827 parent_elm = &parent->ondisk->elms[cursor->parent_index]; 1828 cursor->left_bound = &parent_elm[0].internal.base; 1829 cursor->right_bound = &parent_elm[1].internal.base; 1830 1831 /* 1832 * Assert that the bounds are correct. 1833 */ 1834 KKASSERT(hammer_btree_cmp(cursor->left_bound, 1835 &cursor->node->ondisk->elms[0].leaf.base) <= 0); 1836 KKASSERT(hammer_btree_cmp(cursor->right_bound, 1837 &cursor->node->ondisk->elms[cursor->node->ondisk->count-1].leaf.base) > 0); 1838 KKASSERT(hammer_btree_cmp(cursor->left_bound, &cursor->key_beg) <= 0); 1839 KKASSERT(hammer_btree_cmp(cursor->right_bound, &cursor->key_beg) > 0); 1840 1841 done: 1842 hammer_cursor_downgrade(cursor); 1843 return (error); 1844 } 1845 1846 #if 0 1847 1848 /* 1849 * Recursively correct the right-hand boundary's create_tid to (tid) as 1850 * long as the rest of the key matches. We have to recurse upward in 1851 * the tree as well as down the left side of each parent's right node. 1852 * 1853 * Return EDEADLK if we were only partially successful, forcing the caller 1854 * to try again. The original cursor is not modified. This routine can 1855 * also fail with EDEADLK if it is forced to throw away a portion of its 1856 * record history. 1857 * 1858 * The caller must pass a downgraded cursor to us (otherwise we can't dup it). 1859 */ 1860 struct hammer_rhb { 1861 TAILQ_ENTRY(hammer_rhb) entry; 1862 hammer_node_t node; 1863 int index; 1864 }; 1865 1866 TAILQ_HEAD(hammer_rhb_list, hammer_rhb); 1867 1868 int 1869 hammer_btree_correct_rhb(hammer_cursor_t cursor, hammer_tid_t tid) 1870 { 1871 struct hammer_mount *hmp; 1872 struct hammer_rhb_list rhb_list; 1873 hammer_base_elm_t elm; 1874 hammer_node_t orig_node; 1875 struct hammer_rhb *rhb; 1876 int orig_index; 1877 int error; 1878 1879 TAILQ_INIT(&rhb_list); 1880 hmp = cursor->trans->hmp; 1881 1882 /* 1883 * Save our position so we can restore it on return. This also 1884 * gives us a stable 'elm'. 1885 */ 1886 orig_node = cursor->node; 1887 hammer_ref_node(orig_node); 1888 hammer_lock_sh(&orig_node->lock); 1889 orig_index = cursor->index; 1890 elm = &orig_node->ondisk->elms[orig_index].base; 1891 1892 /* 1893 * Now build a list of parents going up, allocating a rhb 1894 * structure for each one. 1895 */ 1896 while (cursor->parent) { 1897 /* 1898 * Stop if we no longer have any right-bounds to fix up 1899 */ 1900 if (elm->obj_id != cursor->right_bound->obj_id || 1901 elm->rec_type != cursor->right_bound->rec_type || 1902 elm->key != cursor->right_bound->key) { 1903 break; 1904 } 1905 1906 /* 1907 * Stop if the right-hand bound's create_tid does not 1908 * need to be corrected. 1909 */ 1910 if (cursor->right_bound->create_tid >= tid) 1911 break; 1912 1913 rhb = kmalloc(sizeof(*rhb), hmp->m_misc, M_WAITOK|M_ZERO); 1914 rhb->node = cursor->parent; 1915 rhb->index = cursor->parent_index; 1916 hammer_ref_node(rhb->node); 1917 hammer_lock_sh(&rhb->node->lock); 1918 TAILQ_INSERT_HEAD(&rhb_list, rhb, entry); 1919 1920 hammer_cursor_up(cursor); 1921 } 1922 1923 /* 1924 * now safely adjust the right hand bound for each rhb. This may 1925 * also require taking the right side of the tree and iterating down 1926 * ITS left side. 1927 */ 1928 error = 0; 1929 while (error == 0 && (rhb = TAILQ_FIRST(&rhb_list)) != NULL) { 1930 error = hammer_cursor_seek(cursor, rhb->node, rhb->index); 1931 if (error) 1932 break; 1933 TAILQ_REMOVE(&rhb_list, rhb, entry); 1934 hammer_unlock(&rhb->node->lock); 1935 hammer_rel_node(rhb->node); 1936 kfree(rhb, hmp->m_misc); 1937 1938 switch (cursor->node->ondisk->type) { 1939 case HAMMER_BTREE_TYPE_INTERNAL: 1940 /* 1941 * Right-boundary for parent at internal node 1942 * is one element to the right of the element whos 1943 * right boundary needs adjusting. We must then 1944 * traverse down the left side correcting any left 1945 * bounds (which may now be too far to the left). 1946 */ 1947 ++cursor->index; 1948 error = hammer_btree_correct_lhb(cursor, tid); 1949 break; 1950 default: 1951 panic("hammer_btree_correct_rhb(): Bad node type"); 1952 error = EINVAL; 1953 break; 1954 } 1955 } 1956 1957 /* 1958 * Cleanup 1959 */ 1960 while ((rhb = TAILQ_FIRST(&rhb_list)) != NULL) { 1961 TAILQ_REMOVE(&rhb_list, rhb, entry); 1962 hammer_unlock(&rhb->node->lock); 1963 hammer_rel_node(rhb->node); 1964 kfree(rhb, hmp->m_misc); 1965 } 1966 error = hammer_cursor_seek(cursor, orig_node, orig_index); 1967 hammer_unlock(&orig_node->lock); 1968 hammer_rel_node(orig_node); 1969 return (error); 1970 } 1971 1972 /* 1973 * Similar to rhb (in fact, rhb calls lhb), but corrects the left hand 1974 * bound going downward starting at the current cursor position. 1975 * 1976 * This function does not restore the cursor after use. 1977 */ 1978 int 1979 hammer_btree_correct_lhb(hammer_cursor_t cursor, hammer_tid_t tid) 1980 { 1981 struct hammer_rhb_list rhb_list; 1982 hammer_base_elm_t elm; 1983 hammer_base_elm_t cmp; 1984 struct hammer_rhb *rhb; 1985 struct hammer_mount *hmp; 1986 int error; 1987 1988 TAILQ_INIT(&rhb_list); 1989 hmp = cursor->trans->hmp; 1990 1991 cmp = &cursor->node->ondisk->elms[cursor->index].base; 1992 1993 /* 1994 * Record the node and traverse down the left-hand side for all 1995 * matching records needing a boundary correction. 1996 */ 1997 error = 0; 1998 for (;;) { 1999 rhb = kmalloc(sizeof(*rhb), hmp->m_misc, M_WAITOK|M_ZERO); 2000 rhb->node = cursor->node; 2001 rhb->index = cursor->index; 2002 hammer_ref_node(rhb->node); 2003 hammer_lock_sh(&rhb->node->lock); 2004 TAILQ_INSERT_HEAD(&rhb_list, rhb, entry); 2005 2006 if (cursor->node->ondisk->type == HAMMER_BTREE_TYPE_INTERNAL) { 2007 /* 2008 * Nothing to traverse down if we are at the right 2009 * boundary of an internal node. 2010 */ 2011 if (cursor->index == cursor->node->ondisk->count) 2012 break; 2013 } else { 2014 elm = &cursor->node->ondisk->elms[cursor->index].base; 2015 if (elm->btype == HAMMER_BTREE_TYPE_RECORD) 2016 break; 2017 panic("Illegal leaf record type %02x", elm->btype); 2018 } 2019 error = hammer_cursor_down(cursor); 2020 if (error) 2021 break; 2022 2023 elm = &cursor->node->ondisk->elms[cursor->index].base; 2024 if (elm->obj_id != cmp->obj_id || 2025 elm->rec_type != cmp->rec_type || 2026 elm->key != cmp->key) { 2027 break; 2028 } 2029 if (elm->create_tid >= tid) 2030 break; 2031 2032 } 2033 2034 /* 2035 * Now we can safely adjust the left-hand boundary from the bottom-up. 2036 * The last element we remove from the list is the caller's right hand 2037 * boundary, which must also be adjusted. 2038 */ 2039 while (error == 0 && (rhb = TAILQ_FIRST(&rhb_list)) != NULL) { 2040 error = hammer_cursor_seek(cursor, rhb->node, rhb->index); 2041 if (error) 2042 break; 2043 TAILQ_REMOVE(&rhb_list, rhb, entry); 2044 hammer_unlock(&rhb->node->lock); 2045 hammer_rel_node(rhb->node); 2046 kfree(rhb, hmp->m_misc); 2047 2048 elm = &cursor->node->ondisk->elms[cursor->index].base; 2049 if (cursor->node->ondisk->type == HAMMER_BTREE_TYPE_INTERNAL) { 2050 hammer_modify_node(cursor->trans, cursor->node, 2051 &elm->create_tid, 2052 sizeof(elm->create_tid)); 2053 elm->create_tid = tid; 2054 hammer_modify_node_done(cursor->node); 2055 } else { 2056 panic("hammer_btree_correct_lhb(): Bad element type"); 2057 } 2058 } 2059 2060 /* 2061 * Cleanup 2062 */ 2063 while ((rhb = TAILQ_FIRST(&rhb_list)) != NULL) { 2064 TAILQ_REMOVE(&rhb_list, rhb, entry); 2065 hammer_unlock(&rhb->node->lock); 2066 hammer_rel_node(rhb->node); 2067 kfree(rhb, hmp->m_misc); 2068 } 2069 return (error); 2070 } 2071 2072 #endif 2073 2074 /* 2075 * Attempt to remove the locked, empty or want-to-be-empty B-Tree node at 2076 * (cursor->node). Returns 0 on success, EDEADLK if we could not complete 2077 * the operation due to a deadlock, or some other error. 2078 * 2079 * This routine is initially called with an empty leaf and may be 2080 * recursively called with single-element internal nodes. 2081 * 2082 * It should also be noted that when removing empty leaves we must be sure 2083 * to test and update mirror_tid because another thread may have deadlocked 2084 * against us (or someone) trying to propagate it up and cannot retry once 2085 * the node has been deleted. 2086 * 2087 * On return the cursor may end up pointing to an internal node, suitable 2088 * for further iteration but not for an immediate insertion or deletion. 2089 */ 2090 static int 2091 btree_remove(hammer_cursor_t cursor) 2092 { 2093 hammer_node_ondisk_t ondisk; 2094 hammer_btree_elm_t elm; 2095 hammer_node_t node; 2096 hammer_node_t parent; 2097 const int esize = sizeof(*elm); 2098 int error; 2099 2100 node = cursor->node; 2101 2102 /* 2103 * When deleting the root of the filesystem convert it to 2104 * an empty leaf node. Internal nodes cannot be empty. 2105 */ 2106 ondisk = node->ondisk; 2107 if (ondisk->parent == 0) { 2108 KKASSERT(cursor->parent == NULL); 2109 hammer_modify_node_all(cursor->trans, node); 2110 KKASSERT(ondisk == node->ondisk); 2111 ondisk->type = HAMMER_BTREE_TYPE_LEAF; 2112 ondisk->count = 0; 2113 hammer_modify_node_done(node); 2114 cursor->index = 0; 2115 return(0); 2116 } 2117 2118 parent = cursor->parent; 2119 hammer_cursor_removed_node(node, parent, cursor->parent_index); 2120 2121 /* 2122 * Attempt to remove the parent's reference to the child. If the 2123 * parent would become empty we have to recurse. If we fail we 2124 * leave the parent pointing to an empty leaf node. 2125 * 2126 * We have to recurse successfully before we can delete the internal 2127 * node as it is illegal to have empty internal nodes. Even though 2128 * the operation may be aborted we must still fixup any unlocked 2129 * cursors as if we had deleted the element prior to recursing 2130 * (by calling hammer_cursor_deleted_element()) so those cursors 2131 * are properly forced up the chain by the recursion. 2132 */ 2133 if (parent->ondisk->count == 1) { 2134 /* 2135 * This special cursor_up_locked() call leaves the original 2136 * node exclusively locked and referenced, leaves the 2137 * original parent locked (as the new node), and locks the 2138 * new parent. It can return EDEADLK. 2139 */ 2140 error = hammer_cursor_up_locked(cursor); 2141 if (error == 0) { 2142 hammer_cursor_deleted_element(cursor->node, 0); 2143 error = btree_remove(cursor); 2144 if (error == 0) { 2145 hammer_modify_node_all(cursor->trans, node); 2146 ondisk = node->ondisk; 2147 ondisk->type = HAMMER_BTREE_TYPE_DELETED; 2148 ondisk->count = 0; 2149 hammer_modify_node_done(node); 2150 hammer_flush_node(node); 2151 hammer_delete_node(cursor->trans, node); 2152 } else { 2153 kprintf("Warning: BTREE_REMOVE: Defering " 2154 "parent removal1 @ %016llx, skipping\n", 2155 node->node_offset); 2156 } 2157 hammer_unlock(&node->lock); 2158 hammer_rel_node(node); 2159 } else { 2160 kprintf("Warning: BTREE_REMOVE: Defering parent " 2161 "removal2 @ %016llx, skipping\n", 2162 node->node_offset); 2163 } 2164 } else { 2165 KKASSERT(parent->ondisk->count > 1); 2166 2167 hammer_modify_node_all(cursor->trans, parent); 2168 ondisk = parent->ondisk; 2169 KKASSERT(ondisk->type == HAMMER_BTREE_TYPE_INTERNAL); 2170 2171 elm = &ondisk->elms[cursor->parent_index]; 2172 KKASSERT(elm->internal.subtree_offset == node->node_offset); 2173 KKASSERT(ondisk->count > 0); 2174 2175 /* 2176 * We must retain the highest mirror_tid. The deleted 2177 * range is now encompassed by the element to the left. 2178 * If we are already at the left edge the new left edge 2179 * inherits mirror_tid. 2180 * 2181 * Note that bounds of the parent to our parent may create 2182 * a gap to the left of our left-most node or to the right 2183 * of our right-most node. The gap is silently included 2184 * in the mirror_tid's area of effect from the point of view 2185 * of the scan. 2186 */ 2187 if (cursor->parent_index) { 2188 if (elm[-1].internal.mirror_tid < 2189 elm[0].internal.mirror_tid) { 2190 elm[-1].internal.mirror_tid = 2191 elm[0].internal.mirror_tid; 2192 } 2193 } else { 2194 if (elm[1].internal.mirror_tid < 2195 elm[0].internal.mirror_tid) { 2196 elm[1].internal.mirror_tid = 2197 elm[0].internal.mirror_tid; 2198 } 2199 } 2200 2201 /* 2202 * Delete the subtree reference in the parent 2203 */ 2204 bcopy(&elm[1], &elm[0], 2205 (ondisk->count - cursor->parent_index) * esize); 2206 --ondisk->count; 2207 hammer_modify_node_done(parent); 2208 hammer_cursor_deleted_element(parent, cursor->parent_index); 2209 hammer_flush_node(node); 2210 hammer_delete_node(cursor->trans, node); 2211 2212 /* 2213 * cursor->node is invalid, cursor up to make the cursor 2214 * valid again. 2215 */ 2216 error = hammer_cursor_up(cursor); 2217 } 2218 return (error); 2219 } 2220 2221 /* 2222 * Propagate cursor->trans->tid up the B-Tree starting at the current 2223 * cursor position using pseudofs info gleaned from the passed inode. 2224 * 2225 * The passed inode has no relationship to the cursor position other 2226 * then being in the same pseudofs as the insertion or deletion we 2227 * are propagating the mirror_tid for. 2228 */ 2229 void 2230 hammer_btree_do_propagation(hammer_cursor_t cursor, 2231 hammer_pseudofs_inmem_t pfsm, 2232 hammer_btree_leaf_elm_t leaf) 2233 { 2234 hammer_cursor_t ncursor; 2235 hammer_tid_t mirror_tid; 2236 int error; 2237 2238 /* 2239 * We do not propagate a mirror_tid if the filesystem was mounted 2240 * in no-mirror mode. 2241 */ 2242 if (cursor->trans->hmp->master_id < 0) 2243 return; 2244 2245 /* 2246 * This is a bit of a hack because we cannot deadlock or return 2247 * EDEADLK here. The related operation has already completed and 2248 * we must propagate the mirror_tid now regardless. 2249 * 2250 * Generate a new cursor which inherits the original's locks and 2251 * unlock the original. Use the new cursor to propagate the 2252 * mirror_tid. Then clean up the new cursor and reacquire locks 2253 * on the original. 2254 * 2255 * hammer_dup_cursor() cannot dup locks. The dup inherits the 2256 * original's locks and the original is tracked and must be 2257 * re-locked. 2258 */ 2259 mirror_tid = cursor->node->ondisk->mirror_tid; 2260 KKASSERT(mirror_tid != 0); 2261 ncursor = hammer_push_cursor(cursor); 2262 error = hammer_btree_mirror_propagate(ncursor, mirror_tid); 2263 KKASSERT(error == 0); 2264 hammer_pop_cursor(cursor, ncursor); 2265 } 2266 2267 2268 /* 2269 * Propagate a mirror TID update upwards through the B-Tree to the root. 2270 * 2271 * A locked internal node must be passed in. The node will remain locked 2272 * on return. 2273 * 2274 * This function syncs mirror_tid at the specified internal node's element, 2275 * adjusts the node's aggregation mirror_tid, and then recurses upwards. 2276 */ 2277 static int 2278 hammer_btree_mirror_propagate(hammer_cursor_t cursor, hammer_tid_t mirror_tid) 2279 { 2280 hammer_btree_internal_elm_t elm; 2281 hammer_node_t node; 2282 int error; 2283 2284 for (;;) { 2285 error = hammer_cursor_up(cursor); 2286 if (error == 0) 2287 error = hammer_cursor_upgrade(cursor); 2288 while (error == EDEADLK) { 2289 hammer_recover_cursor(cursor); 2290 error = hammer_cursor_upgrade(cursor); 2291 } 2292 if (error) 2293 break; 2294 node = cursor->node; 2295 KKASSERT (node->ondisk->type == HAMMER_BTREE_TYPE_INTERNAL); 2296 2297 /* 2298 * Adjust the node's element 2299 */ 2300 elm = &node->ondisk->elms[cursor->index].internal; 2301 if (elm->mirror_tid >= mirror_tid) 2302 break; 2303 hammer_modify_node(cursor->trans, node, &elm->mirror_tid, 2304 sizeof(elm->mirror_tid)); 2305 elm->mirror_tid = mirror_tid; 2306 hammer_modify_node_done(node); 2307 if (hammer_debug_general & 0x0002) { 2308 kprintf("mirror_propagate: propagate " 2309 "%016llx @%016llx:%d\n", 2310 mirror_tid, node->node_offset, cursor->index); 2311 } 2312 2313 2314 /* 2315 * Adjust the node's mirror_tid aggregator 2316 */ 2317 if (node->ondisk->mirror_tid >= mirror_tid) 2318 return(0); 2319 hammer_modify_node_field(cursor->trans, node, mirror_tid); 2320 node->ondisk->mirror_tid = mirror_tid; 2321 hammer_modify_node_done(node); 2322 if (hammer_debug_general & 0x0002) { 2323 kprintf("mirror_propagate: propagate " 2324 "%016llx @%016llx\n", 2325 mirror_tid, node->node_offset); 2326 } 2327 } 2328 if (error == ENOENT) 2329 error = 0; 2330 return(error); 2331 } 2332 2333 hammer_node_t 2334 hammer_btree_get_parent(hammer_transaction_t trans, hammer_node_t node, 2335 int *parent_indexp, int *errorp, int try_exclusive) 2336 { 2337 hammer_node_t parent; 2338 hammer_btree_elm_t elm; 2339 int i; 2340 2341 /* 2342 * Get the node 2343 */ 2344 parent = hammer_get_node(trans, node->ondisk->parent, 0, errorp); 2345 if (*errorp) { 2346 KKASSERT(parent == NULL); 2347 return(NULL); 2348 } 2349 KKASSERT ((parent->flags & HAMMER_NODE_DELETED) == 0); 2350 2351 /* 2352 * Lock the node 2353 */ 2354 if (try_exclusive) { 2355 if (hammer_lock_ex_try(&parent->lock)) { 2356 hammer_rel_node(parent); 2357 *errorp = EDEADLK; 2358 return(NULL); 2359 } 2360 } else { 2361 hammer_lock_sh(&parent->lock); 2362 } 2363 2364 /* 2365 * Figure out which element in the parent is pointing to the 2366 * child. 2367 */ 2368 if (node->ondisk->count) { 2369 i = hammer_btree_search_node(&node->ondisk->elms[0].base, 2370 parent->ondisk); 2371 } else { 2372 i = 0; 2373 } 2374 while (i < parent->ondisk->count) { 2375 elm = &parent->ondisk->elms[i]; 2376 if (elm->internal.subtree_offset == node->node_offset) 2377 break; 2378 ++i; 2379 } 2380 if (i == parent->ondisk->count) { 2381 hammer_unlock(&parent->lock); 2382 panic("Bad B-Tree link: parent %p node %p\n", parent, node); 2383 } 2384 *parent_indexp = i; 2385 KKASSERT(*errorp == 0); 2386 return(parent); 2387 } 2388 2389 /* 2390 * The element (elm) has been moved to a new internal node (node). 2391 * 2392 * If the element represents a pointer to an internal node that node's 2393 * parent must be adjusted to the element's new location. 2394 * 2395 * XXX deadlock potential here with our exclusive locks 2396 */ 2397 int 2398 btree_set_parent(hammer_transaction_t trans, hammer_node_t node, 2399 hammer_btree_elm_t elm) 2400 { 2401 hammer_node_t child; 2402 int error; 2403 2404 error = 0; 2405 2406 switch(elm->base.btype) { 2407 case HAMMER_BTREE_TYPE_INTERNAL: 2408 case HAMMER_BTREE_TYPE_LEAF: 2409 child = hammer_get_node(trans, elm->internal.subtree_offset, 2410 0, &error); 2411 if (error == 0) { 2412 hammer_modify_node_field(trans, child, parent); 2413 child->ondisk->parent = node->node_offset; 2414 hammer_modify_node_done(child); 2415 hammer_rel_node(child); 2416 } 2417 break; 2418 default: 2419 break; 2420 } 2421 return(error); 2422 } 2423 2424 /* 2425 * Exclusively lock all the children of node. This is used by the split 2426 * code to prevent anyone from accessing the children of a cursor node 2427 * while we fix-up its parent offset. 2428 * 2429 * If we don't lock the children we can really mess up cursors which block 2430 * trying to cursor-up into our node. 2431 * 2432 * On failure EDEADLK (or some other error) is returned. If a deadlock 2433 * error is returned the cursor is adjusted to block on termination. 2434 */ 2435 int 2436 hammer_btree_lock_children(hammer_cursor_t cursor, 2437 struct hammer_node_locklist **locklistp) 2438 { 2439 hammer_node_t node; 2440 hammer_node_locklist_t item; 2441 hammer_node_ondisk_t ondisk; 2442 hammer_btree_elm_t elm; 2443 hammer_node_t child; 2444 struct hammer_mount *hmp; 2445 int error; 2446 int i; 2447 2448 node = cursor->node; 2449 ondisk = node->ondisk; 2450 error = 0; 2451 hmp = cursor->trans->hmp; 2452 2453 /* 2454 * We really do not want to block on I/O with exclusive locks held, 2455 * pre-get the children before trying to lock the mess. 2456 */ 2457 for (i = 0; i < ondisk->count; ++i) { 2458 ++hammer_stats_btree_elements; 2459 elm = &ondisk->elms[i]; 2460 if (elm->base.btype != HAMMER_BTREE_TYPE_LEAF && 2461 elm->base.btype != HAMMER_BTREE_TYPE_INTERNAL) { 2462 continue; 2463 } 2464 child = hammer_get_node(cursor->trans, 2465 elm->internal.subtree_offset, 2466 0, &error); 2467 if (child) 2468 hammer_rel_node(child); 2469 } 2470 2471 /* 2472 * Do it for real 2473 */ 2474 for (i = 0; error == 0 && i < ondisk->count; ++i) { 2475 ++hammer_stats_btree_elements; 2476 elm = &ondisk->elms[i]; 2477 2478 switch(elm->base.btype) { 2479 case HAMMER_BTREE_TYPE_INTERNAL: 2480 case HAMMER_BTREE_TYPE_LEAF: 2481 KKASSERT(elm->internal.subtree_offset != 0); 2482 child = hammer_get_node(cursor->trans, 2483 elm->internal.subtree_offset, 2484 0, &error); 2485 break; 2486 default: 2487 child = NULL; 2488 break; 2489 } 2490 if (child) { 2491 if (hammer_lock_ex_try(&child->lock) != 0) { 2492 if (cursor->deadlk_node == NULL) { 2493 cursor->deadlk_node = child; 2494 hammer_ref_node(cursor->deadlk_node); 2495 } 2496 error = EDEADLK; 2497 hammer_rel_node(child); 2498 } else { 2499 item = kmalloc(sizeof(*item), 2500 hmp->m_misc, M_WAITOK); 2501 item->next = *locklistp; 2502 item->node = child; 2503 *locklistp = item; 2504 } 2505 } 2506 } 2507 if (error) 2508 hammer_btree_unlock_children(cursor, locklistp); 2509 return(error); 2510 } 2511 2512 2513 /* 2514 * Release previously obtained node locks. 2515 */ 2516 void 2517 hammer_btree_unlock_children(hammer_cursor_t cursor, 2518 struct hammer_node_locklist **locklistp) 2519 { 2520 hammer_node_locklist_t item; 2521 2522 while ((item = *locklistp) != NULL) { 2523 *locklistp = item->next; 2524 hammer_unlock(&item->node->lock); 2525 hammer_rel_node(item->node); 2526 kfree(item, cursor->trans->hmp->m_misc); 2527 } 2528 } 2529 2530 /************************************************************************ 2531 * MISCELLANIOUS SUPPORT * 2532 ************************************************************************/ 2533 2534 /* 2535 * Compare two B-Tree elements, return -N, 0, or +N (e.g. similar to strcmp). 2536 * 2537 * Note that for this particular function a return value of -1, 0, or +1 2538 * can denote a match if create_tid is otherwise discounted. A create_tid 2539 * of zero is considered to be 'infinity' in comparisons. 2540 * 2541 * See also hammer_rec_rb_compare() and hammer_rec_cmp() in hammer_object.c. 2542 */ 2543 int 2544 hammer_btree_cmp(hammer_base_elm_t key1, hammer_base_elm_t key2) 2545 { 2546 if (key1->localization < key2->localization) 2547 return(-5); 2548 if (key1->localization > key2->localization) 2549 return(5); 2550 2551 if (key1->obj_id < key2->obj_id) 2552 return(-4); 2553 if (key1->obj_id > key2->obj_id) 2554 return(4); 2555 2556 if (key1->rec_type < key2->rec_type) 2557 return(-3); 2558 if (key1->rec_type > key2->rec_type) 2559 return(3); 2560 2561 if (key1->key < key2->key) 2562 return(-2); 2563 if (key1->key > key2->key) 2564 return(2); 2565 2566 /* 2567 * A create_tid of zero indicates a record which is undeletable 2568 * and must be considered to have a value of positive infinity. 2569 */ 2570 if (key1->create_tid == 0) { 2571 if (key2->create_tid == 0) 2572 return(0); 2573 return(1); 2574 } 2575 if (key2->create_tid == 0) 2576 return(-1); 2577 if (key1->create_tid < key2->create_tid) 2578 return(-1); 2579 if (key1->create_tid > key2->create_tid) 2580 return(1); 2581 return(0); 2582 } 2583 2584 /* 2585 * Test a timestamp against an element to determine whether the 2586 * element is visible. A timestamp of 0 means 'infinity'. 2587 */ 2588 int 2589 hammer_btree_chkts(hammer_tid_t asof, hammer_base_elm_t base) 2590 { 2591 if (asof == 0) { 2592 if (base->delete_tid) 2593 return(1); 2594 return(0); 2595 } 2596 if (asof < base->create_tid) 2597 return(-1); 2598 if (base->delete_tid && asof >= base->delete_tid) 2599 return(1); 2600 return(0); 2601 } 2602 2603 /* 2604 * Create a separator half way inbetween key1 and key2. For fields just 2605 * one unit apart, the separator will match key2. key1 is on the left-hand 2606 * side and key2 is on the right-hand side. 2607 * 2608 * key2 must be >= the separator. It is ok for the separator to match key2. 2609 * 2610 * NOTE: Even if key1 does not match key2, the separator may wind up matching 2611 * key2. 2612 * 2613 * NOTE: It might be beneficial to just scrap this whole mess and just 2614 * set the separator to key2. 2615 */ 2616 #define MAKE_SEPARATOR(key1, key2, dest, field) \ 2617 dest->field = key1->field + ((key2->field - key1->field + 1) >> 1); 2618 2619 static void 2620 hammer_make_separator(hammer_base_elm_t key1, hammer_base_elm_t key2, 2621 hammer_base_elm_t dest) 2622 { 2623 bzero(dest, sizeof(*dest)); 2624 2625 dest->rec_type = key2->rec_type; 2626 dest->key = key2->key; 2627 dest->obj_id = key2->obj_id; 2628 dest->create_tid = key2->create_tid; 2629 2630 MAKE_SEPARATOR(key1, key2, dest, localization); 2631 if (key1->localization == key2->localization) { 2632 MAKE_SEPARATOR(key1, key2, dest, obj_id); 2633 if (key1->obj_id == key2->obj_id) { 2634 MAKE_SEPARATOR(key1, key2, dest, rec_type); 2635 if (key1->rec_type == key2->rec_type) { 2636 MAKE_SEPARATOR(key1, key2, dest, key); 2637 /* 2638 * Don't bother creating a separator for 2639 * create_tid, which also conveniently avoids 2640 * having to handle the create_tid == 0 2641 * (infinity) case. Just leave create_tid 2642 * set to key2. 2643 * 2644 * Worst case, dest matches key2 exactly, 2645 * which is acceptable. 2646 */ 2647 } 2648 } 2649 } 2650 } 2651 2652 #undef MAKE_SEPARATOR 2653 2654 /* 2655 * Return whether a generic internal or leaf node is full 2656 */ 2657 static int 2658 btree_node_is_full(hammer_node_ondisk_t node) 2659 { 2660 switch(node->type) { 2661 case HAMMER_BTREE_TYPE_INTERNAL: 2662 if (node->count == HAMMER_BTREE_INT_ELMS) 2663 return(1); 2664 break; 2665 case HAMMER_BTREE_TYPE_LEAF: 2666 if (node->count == HAMMER_BTREE_LEAF_ELMS) 2667 return(1); 2668 break; 2669 default: 2670 panic("illegal btree subtype"); 2671 } 2672 return(0); 2673 } 2674 2675 #if 0 2676 static int 2677 btree_max_elements(u_int8_t type) 2678 { 2679 if (type == HAMMER_BTREE_TYPE_LEAF) 2680 return(HAMMER_BTREE_LEAF_ELMS); 2681 if (type == HAMMER_BTREE_TYPE_INTERNAL) 2682 return(HAMMER_BTREE_INT_ELMS); 2683 panic("btree_max_elements: bad type %d\n", type); 2684 } 2685 #endif 2686 2687 void 2688 hammer_print_btree_node(hammer_node_ondisk_t ondisk) 2689 { 2690 hammer_btree_elm_t elm; 2691 int i; 2692 2693 kprintf("node %p count=%d parent=%016llx type=%c\n", 2694 ondisk, ondisk->count, ondisk->parent, ondisk->type); 2695 2696 /* 2697 * Dump both boundary elements if an internal node 2698 */ 2699 if (ondisk->type == HAMMER_BTREE_TYPE_INTERNAL) { 2700 for (i = 0; i <= ondisk->count; ++i) { 2701 elm = &ondisk->elms[i]; 2702 hammer_print_btree_elm(elm, ondisk->type, i); 2703 } 2704 } else { 2705 for (i = 0; i < ondisk->count; ++i) { 2706 elm = &ondisk->elms[i]; 2707 hammer_print_btree_elm(elm, ondisk->type, i); 2708 } 2709 } 2710 } 2711 2712 void 2713 hammer_print_btree_elm(hammer_btree_elm_t elm, u_int8_t type, int i) 2714 { 2715 kprintf(" %2d", i); 2716 kprintf("\tobj_id = %016llx\n", elm->base.obj_id); 2717 kprintf("\tkey = %016llx\n", elm->base.key); 2718 kprintf("\tcreate_tid = %016llx\n", elm->base.create_tid); 2719 kprintf("\tdelete_tid = %016llx\n", elm->base.delete_tid); 2720 kprintf("\trec_type = %04x\n", elm->base.rec_type); 2721 kprintf("\tobj_type = %02x\n", elm->base.obj_type); 2722 kprintf("\tbtype = %02x (%c)\n", 2723 elm->base.btype, 2724 (elm->base.btype ? elm->base.btype : '?')); 2725 kprintf("\tlocalization = %02x\n", elm->base.localization); 2726 2727 switch(type) { 2728 case HAMMER_BTREE_TYPE_INTERNAL: 2729 kprintf("\tsubtree_off = %016llx\n", 2730 elm->internal.subtree_offset); 2731 break; 2732 case HAMMER_BTREE_TYPE_RECORD: 2733 kprintf("\tdata_offset = %016llx\n", elm->leaf.data_offset); 2734 kprintf("\tdata_len = %08x\n", elm->leaf.data_len); 2735 kprintf("\tdata_crc = %08x\n", elm->leaf.data_crc); 2736 break; 2737 } 2738 } 2739