AMD64 - Fix many compile-time warnings. int/ptr type mismatches, %llx, etc.
[dragonfly.git] / sys / vfs / hammer / hammer_rebalance.c
CommitLineData
1775b6a0
MD
1/*
2 * Copyright (c) 2009 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
35#include "hammer.h"
36
37static int rebalance_node(struct hammer_ioc_rebalance *rebal,
38 hammer_cursor_t cursor);
39static void rebalance_closeout(hammer_node_lock_t base_item, int base_count,
40 hammer_btree_elm_t elm);
41static void rebalance_parent_ptrs(hammer_node_lock_t base_item, int index,
42 hammer_node_lock_t item, hammer_node_lock_t chld_item);
43
44/*
45 * Iterate through the specified range of object ids and rebalance B-Tree
46 * leaf and internal nodes we encounter. A forwards iteration is used.
47 *
48 * All leafs are at the same depth. We use the b-tree scan code loosely
49 * to position ourselves and create degenerate cases to skip indices
50 * that we have rebalanced in bulk.
51 */
52
53int
54hammer_ioc_rebalance(hammer_transaction_t trans, hammer_inode_t ip,
55 struct hammer_ioc_rebalance *rebal)
56{
57 struct hammer_cursor cursor;
58 hammer_btree_leaf_elm_t elm;
59 int error;
60 int seq;
61
62 if ((rebal->key_beg.localization | rebal->key_end.localization) &
63 HAMMER_LOCALIZE_PSEUDOFS_MASK) {
64 return(EINVAL);
65 }
66 if (rebal->key_beg.localization > rebal->key_end.localization)
67 return(EINVAL);
68 if (rebal->key_beg.localization == rebal->key_end.localization) {
69 if (rebal->key_beg.obj_id > rebal->key_end.obj_id)
70 return(EINVAL);
71 /* key-space limitations - no check needed */
72 }
73 if (rebal->saturation < HAMMER_BTREE_INT_ELMS / 2)
74 rebal->saturation = HAMMER_BTREE_INT_ELMS / 2;
75 if (rebal->saturation > HAMMER_BTREE_INT_ELMS)
76 rebal->saturation = HAMMER_BTREE_INT_ELMS;
77
78 rebal->key_cur = rebal->key_beg;
79 rebal->key_cur.localization &= HAMMER_LOCALIZE_MASK;
80 rebal->key_cur.localization += ip->obj_localization;
81
82 seq = trans->hmp->flusher.act;
83
84 /*
85 * Scan forwards. Retries typically occur if a deadlock is detected.
86 */
87retry:
88 error = hammer_init_cursor(trans, &cursor, NULL, NULL);
89 if (error) {
90 hammer_done_cursor(&cursor);
91 goto failed;
92 }
93 cursor.key_beg = rebal->key_cur;
94 cursor.key_end = rebal->key_end;
95 cursor.key_end.localization &= HAMMER_LOCALIZE_MASK;
96 cursor.key_end.localization += ip->obj_localization;
97 cursor.flags |= HAMMER_CURSOR_END_INCLUSIVE;
98 cursor.flags |= HAMMER_CURSOR_BACKEND;
99
100 /*
101 * Cause internal nodes to be returned on the way up. Internal nodes
102 * are not returned on the way down so we can create a degenerate
103 * case to handle internal nodes as a trailing function of their
104 * sub-trees.
105 *
106 * Note that by not setting INSERTING or PRUNING no boundary
107 * corrections will be made and a sync lock is not needed for the
108 * B-Tree scan itself.
109 */
110 cursor.flags |= HAMMER_CURSOR_REBLOCKING;
111
112 error = hammer_btree_first(&cursor);
113
114 while (error == 0) {
115 /*
116 * We only care about internal nodes visited for the last
117 * time on the way up... that is, a trailing scan of the
118 * internal node after all of its children have been recursed
119 * through.
120 */
121 if (cursor.node->ondisk->type == HAMMER_BTREE_TYPE_INTERNAL) {
122 /*
123 * Leave cursor.index alone, we want to recurse
124 * through all children of the internal node before
125 * visiting it.
126 *
127 * Process the internal node on the way up after
128 * the last child's sub-tree has been balanced.
129 */
130 if (cursor.index == cursor.node->ondisk->count - 1) {
131 hammer_sync_lock_sh(trans);
132 error = rebalance_node(rebal, &cursor);
133 hammer_sync_unlock(trans);
134 }
135 } else {
136 /*
137 * We don't need to iterate through all the leaf
138 * elements, we only care about the parent (internal)
139 * node.
140 */
141 cursor.index = cursor.node->ondisk->count - 1;
142 }
143 if (error)
144 break;
145
146 /*
147 * Update returned scan position and do a flush if
148 * necessary.
149 */
150 elm = &cursor.node->ondisk->elms[cursor.index].leaf;
151 rebal->key_cur = elm->base;
152 ++rebal->stat_ncount;
153
154 while (hammer_flusher_meta_halflimit(trans->hmp) ||
155 hammer_flusher_undo_exhausted(trans, 2)) {
156 hammer_unlock_cursor(&cursor);
157 hammer_flusher_wait(trans->hmp, seq);
158 hammer_lock_cursor(&cursor);
159 seq = hammer_flusher_async_one(trans->hmp);
160 }
161
162 /*
163 * Iterate, stop if a signal was received.
164 */
165 if ((error = hammer_signal_check(trans->hmp)) != 0)
166 break;
167 error = hammer_btree_iterate(&cursor);
168 }
169 if (error == ENOENT)
170 error = 0;
171 hammer_done_cursor(&cursor);
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172 if (error == EDEADLK) {
173 ++rebal->stat_collisions;
1775b6a0 174 goto retry;
7ddc70d1 175 }
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176 if (error == EINTR) {
177 rebal->head.flags |= HAMMER_IOC_HEAD_INTR;
178 error = 0;
179 }
180failed:
181 rebal->key_cur.localization &= HAMMER_LOCALIZE_MASK;
182 return(error);
183}
184
185/*
186 * Rebalance an internal node, called via a trailing upward recursion.
187 * All the children have already been individually rebalanced.
188 *
189 * To rebalance we scan the elements in the children and pack them,
190 * so we actually need to lock the children and the children's children.
191 *
192 * INTERNAL_NODE
193 * / / | | | \ \
194 * C C C C C C C children (first level) (internal or leaf nodes)
195 * children's elements (second level)
196 *
197 * <<<---------- pack children's elements, possibly remove excess
198 * children after packing.
199 *
200 * NOTE: The mirror_tids, parent pointers, and child pointers must be updated.
201 * Any live tracked B-Tree nodes must be updated (we worm out of that
202 * by not allowing any). And boundary elements must be preserved.
203 *
204 * NOTE: If the children are leaf nodes we may have a degenerate case
205 * case where there are no elements in the leafs.
206 *
207 * XXX live-tracked
208 */
209static int
210rebalance_node(struct hammer_ioc_rebalance *rebal, hammer_cursor_t cursor)
211{
212 struct hammer_node_lock lockroot;
213 hammer_node_lock_t base_item;
214 hammer_node_lock_t chld_item;
215 hammer_node_lock_t item;
216 hammer_btree_elm_t elm;
217 hammer_node_t node;
218 u_int8_t type1;
219 int base_count;
220 int root_count;
221 int avg_elms;
222 int count;
223 int error;
224 int i;
225 int n;
226
227 /*
228 * Lock the parent node via the cursor, collect and lock our
229 * children and children's children.
230 *
231 * By the way, this is a LOT of locks.
232 */
233 hammer_node_lock_init(&lockroot, cursor->node);
234 error = hammer_cursor_upgrade(cursor);
235 if (error)
236 goto done;
237 error = hammer_btree_lock_children(cursor, 2, &lockroot);
238 if (error)
239 goto done;
240
241 /*
242 * Make a copy of all the locked on-disk data to simplify the element
243 * shifting we are going to have to do. We will modify the copy
244 * first.
245 */
246 hammer_btree_lock_copy(cursor, &lockroot);
247
248 /*
249 * Look at the first child node.
250 */
251 if (TAILQ_FIRST(&lockroot.list) == NULL)
252 goto done;
253 type1 = TAILQ_FIRST(&lockroot.list)->node->ondisk->type;
254
255 /*
256 * Figure out the total number of children's children and
257 * calculate the average number of elements per child.
258 *
259 * The minimum avg_elms is 1 when count > 0. avg_elms * root_elms
260 * is always greater or equal to count.
261 *
262 * If count == 0 we hit a degenerate case which will cause
263 * avg_elms to also calculate as 0.
264 */
265 if (hammer_debug_general & 0x1000)
266 kprintf("lockroot %p count %d\n", &lockroot, lockroot.count);
267 count = 0;
268 TAILQ_FOREACH(item, &lockroot.list, entry) {
269 if (hammer_debug_general & 0x1000)
270 kprintf("add count %d\n", item->count);
271 count += item->count;
272 KKASSERT(item->node->ondisk->type == type1);
273 }
274 avg_elms = (count + (lockroot.count - 1)) / lockroot.count;
275 KKASSERT(avg_elms >= 0);
276
277 /*
278 * If the average number of elements per child is too low then
279 * calculate the desired number of children (n) such that the
280 * average number of elements is reasonable.
281 *
282 * If the desired number of children is 1 then avg_elms will
283 * wind up being count, which may still be smaller then saturation
284 * but that is ok.
285 */
286 if (count && avg_elms < rebal->saturation) {
287 n = (count + (rebal->saturation - 1)) / rebal->saturation;
288 avg_elms = (count + (n - 1)) / n;
289 }
290
291 /*
292 * Pack the elements in the children. Elements for each item is
293 * packed into base_item until avg_elms is reached, then base_item
294 * iterates.
295 *
296 * hammer_cursor_moved_element() is called for each element moved
297 * to update tracked cursors, including the index beyond the last
298 * element (at count).
299 */
300 base_item = TAILQ_FIRST(&lockroot.list);
301 base_count = 0;
302 root_count = 0;
303
304 TAILQ_FOREACH(item, &lockroot.list, entry) {
305 node = item->node;
306 KKASSERT(item->count == node->ondisk->count);
307 chld_item = TAILQ_FIRST(&item->list);
308 for (i = 0; i < item->count; ++i) {
309 /*
310 * Closeout. If the next element is at index 0
311 * just use the existing separator in the parent.
312 */
313 if (base_count == avg_elms) {
314 if (i == 0) {
315 elm = &lockroot.node->ondisk->elms[
316 item->index];
317 } else {
318 elm = &node->ondisk->elms[i];
319 }
320 rebalance_closeout(base_item, base_count, elm);
321 base_item = TAILQ_NEXT(base_item, entry);
322 KKASSERT(base_item);
323 base_count = 0;
324 ++root_count;
325 }
326
327 /*
328 * Check degenerate no-work case. Otherwise pack
329 * the element.
330 *
331 * All changes are made to the copy.
332 */
333 if (item == base_item && i == base_count) {
334 ++base_count;
335 if (chld_item)
336 chld_item = TAILQ_NEXT(chld_item, entry);
337 continue;
338 }
339
340 /*
341 * Pack element.
342 */
343 elm = &base_item->copy->elms[base_count];
344 *elm = node->ondisk->elms[i];
345 base_item->flags |= HAMMER_NODE_LOCK_UPDATED;
346
347 /*
348 * Adjust the mirror_tid of the target. The parent
349 * node (lockroot.node) should already have an
350 * aggregate mirror_tid so we do not have to update
351 * that.
352 */
353 if (base_item->copy->mirror_tid <
354 node->ondisk->mirror_tid) {
355 base_item->copy->mirror_tid =
356 node->ondisk->mirror_tid;
357 KKASSERT(lockroot.node->ondisk->mirror_tid >=
358 node->ondisk->mirror_tid);
359 base_item->flags |= HAMMER_NODE_LOCK_UPDATED;
360 }
361
362 /*
363 * We moved elm. The parent pointers for any
364 * children of elm must be repointed.
365 */
366 if (item != base_item &&
367 node->ondisk->type == HAMMER_BTREE_TYPE_INTERNAL) {
368 KKASSERT(chld_item);
369 rebalance_parent_ptrs(base_item, base_count,
370 item, chld_item);
371 }
372 hammer_cursor_moved_element(node, base_item->node,
373 i, base_count);
374 ++base_count;
375 if (chld_item)
376 chld_item = TAILQ_NEXT(chld_item, entry);
377 }
378
379 /*
380 * Always call at the end (i == number of elements) in
381 * case a cursor is sitting indexed there.
382 */
383 hammer_cursor_moved_element(node, base_item->node,
384 i, base_count);
385 }
386
387 /*
388 * Packing complete, close-out base_item using the right-hand
389 * boundary of the original parent.
390 *
391 * If we will be deleting nodes from the root shift the old
392 * right-hand-boundary to the new ending index.
393 */
394 elm = &lockroot.node->ondisk->elms[lockroot.node->ondisk->count];
395 rebalance_closeout(base_item, base_count, elm);
396 ++root_count;
397 if (lockroot.copy->count != root_count) {
398 lockroot.copy->count = root_count;
399 lockroot.copy->elms[root_count] = *elm;
400 lockroot.flags |= HAMMER_NODE_LOCK_UPDATED;
401 }
402
403 /*
404 * Any extra items beyond base_item are now completely empty and
405 * can be destroyed. Queue the destruction up in the copy. Note
406 * that none of the destroyed nodes are part of our cursor.
407 *
408 * The cursor is locked so it isn't on the tracking list. It
409 * should have been pointing at the boundary element (at root_count).
410 * When deleting elements from the root (which is cursor.node), we
411 * have to update the cursor.index manually to keep it in bounds.
412 */
413 while ((base_item = TAILQ_NEXT(base_item, entry)) != NULL) {
414 hammer_cursor_removed_node(base_item->node, lockroot.node,
415 base_count);
416 hammer_cursor_deleted_element(lockroot.node, base_count);
417 base_item->copy->type = HAMMER_BTREE_TYPE_DELETED;
418 base_item->copy->count = 0;
419 base_item->flags |= HAMMER_NODE_LOCK_UPDATED;
420 if (cursor->index > lockroot.copy->count)
421 --cursor->index;
7ddc70d1 422 ++rebal->stat_deletions;
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423 }
424
425 /*
426 * All done, sync the locked child tree to disk. This will also
427 * flush and delete deleted nodes.
428 */
7ddc70d1 429 rebal->stat_nrebal += hammer_btree_sync_copy(cursor, &lockroot);
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430done:
431 hammer_btree_unlock_children(cursor, &lockroot);
432 hammer_cursor_downgrade(cursor);
433 return (error);
434}
435
436/*
437 * Close-out the child base_item. This node contains base_count
438 * elements.
439 *
440 * If the node is an internal node the right-hand boundary must be
441 * set to elm.
442 */
443static
444void
445rebalance_closeout(hammer_node_lock_t base_item, int base_count,
446 hammer_btree_elm_t elm)
447{
448 hammer_node_lock_t parent;
449 hammer_btree_elm_t base_elm;
450 hammer_btree_elm_t rbound_elm;
451 u_int8_t save;
452
453 /*
454 * Update the count. NOTE: base_count can be 0 for the
455 * degenerate leaf case.
456 */
457 if (hammer_debug_general & 0x1000) {
458 kprintf("rebalance_closeout %016llx:",
973c11b9 459 (long long)base_item->node->node_offset);
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MD
460 }
461 if (base_item->copy->count != base_count) {
462 base_item->flags |= HAMMER_NODE_LOCK_UPDATED;
463 base_item->copy->count = base_count;
464 if (hammer_debug_general & 0x1000)
465 kprintf(" (count update)");
466 }
467
468 /*
469 * If we are closing out an internal node we must assign
470 * a right-hand boundary. Use the element contents as the
471 * right-hand boundary.
472 *
473 * Internal nodes are required to have at least one child,
474 * otherwise the left and right boundary would end up being
475 * the same element. Only leaf nodes can be empty.
7ddc70d1
MD
476 *
477 * Rebalancing may cut-off an internal node such that the
478 * new right hand boundary is the next element anyway, but
479 * we still have to make sure that subtree_offset, btype,
480 * and mirror_tid are all 0.
1775b6a0
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481 */
482 if (base_item->copy->type == HAMMER_BTREE_TYPE_INTERNAL) {
483 KKASSERT(base_count != 0);
484 base_elm = &base_item->copy->elms[base_count];
485
7ddc70d1
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486 if (bcmp(base_elm, elm, sizeof(*elm)) != 0 ||
487 elm->internal.subtree_offset ||
488 elm->internal.mirror_tid ||
489 elm->base.btype) {
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490 *base_elm = *elm;
491 base_elm->internal.subtree_offset = 0;
7ddc70d1 492 base_elm->internal.mirror_tid = 0;
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493 base_elm->base.btype = 0;
494 base_item->flags |= HAMMER_NODE_LOCK_UPDATED;
495 if (hammer_debug_general & 0x1000)
496 kprintf(" (rhs update)");
497 } else {
498 if (hammer_debug_general & 0x1000)
499 kprintf(" (rhs same)");
500 }
501 }
502
503 /*
504 * The parent's boundary must be updated. Be careful to retain
505 * the btype and non-base internal fields as that information is
506 * unrelated.
507 */
508 parent = base_item->parent;
509 rbound_elm = &parent->copy->elms[base_item->index + 1];
510 if (bcmp(&rbound_elm->base, &elm->base, sizeof(elm->base)) != 0) {
511 save = rbound_elm->base.btype;
512 rbound_elm->base = elm->base;
513 rbound_elm->base.btype = save;
514 parent->flags |= HAMMER_NODE_LOCK_UPDATED;
515 if (hammer_debug_general & 0x1000) {
516 kprintf(" (parent bound update %d)",
517 base_item->index + 1);
518 }
519 }
520 if (hammer_debug_general & 0x1000)
521 kprintf("\n");
522}
523
524/*
525 * An element in item has moved to base_item. We must update the parent
526 * pointer of the node the element points to (which is chld_item).
527 */
528static
529void
530rebalance_parent_ptrs(hammer_node_lock_t base_item, int index,
531 hammer_node_lock_t item, hammer_node_lock_t chld_item)
532{
533 KKASSERT(chld_item->node->ondisk->parent == item->node->node_offset);
534 chld_item->copy->parent = base_item->node->node_offset;
535 chld_item->flags |= HAMMER_NODE_LOCK_UPDATED;
536 hammer_cursor_parent_changed(chld_item->node,
537 item->node, base_item->node, index);
538}