1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2013 by Delphix. All rights reserved.
24 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
25 */
26
27 #include <sys/zfs_context.h>
28 #include <sys/dmu.h>
29 #include <sys/dmu_tx.h>
30 #include <sys/space_map.h>
31 #include <sys/metaslab_impl.h>
32 #include <sys/vdev_impl.h>
33 #include <sys/zio.h>
34 #include <sys/spa_impl.h>
35
36 /*
37 * Allow allocations to switch to gang blocks quickly. We do this to
38 * avoid having to load lots of space_maps in a given txg. There are,
39 * however, some cases where we want to avoid "fast" ganging and instead
40 * we want to do an exhaustive search of all metaslabs on this device.
41 * Currently we don't allow any gang, zil, or dump device related allocations
42 * to "fast" gang.
43 */
44 #define CAN_FASTGANG(flags) \
45 (!((flags) & (METASLAB_GANG_CHILD | METASLAB_GANG_HEADER | \
46 METASLAB_GANG_AVOID)))
47
48 #define METASLAB_WEIGHT_PRIMARY (1ULL << 63)
49 #define METASLAB_WEIGHT_SECONDARY (1ULL << 62)
50 #define METASLAB_ACTIVE_MASK \
51 (METASLAB_WEIGHT_PRIMARY | METASLAB_WEIGHT_SECONDARY)
52
53 uint64_t metaslab_aliquot = 512ULL << 10;
54 uint64_t metaslab_gang_bang = SPA_MAXBLOCKSIZE + 1; /* force gang blocks */
55
56 /*
57 * The in-core space map representation is more compact than its on-disk form.
58 * The zfs_condense_pct determines how much more compact the in-core
59 * space_map representation must be before we compact it on-disk.
60 * Values should be greater than or equal to 100.
61 */
62 int zfs_condense_pct = 200;
63
64 /*
65 * This value defines the number of allowed allocation failures per vdev.
66 * If a device reaches this threshold in a given txg then we consider skipping
67 * allocations on that device. The value of zfs_mg_alloc_failures is computed
68 * in zio_init() unless it has been overridden in /etc/system.
69 */
70 int zfs_mg_alloc_failures = 0;
71
72 /*
73 * The zfs_mg_noalloc_threshold defines which metaslab groups should
74 * be eligible for allocation. The value is defined as a percentage of
75 * a free space. Metaslab groups that have more free space than
76 * zfs_mg_noalloc_threshold are always eligible for allocations. Once
77 * a metaslab group's free space is less than or equal to the
78 * zfs_mg_noalloc_threshold the allocator will avoid allocating to that
79 * group unless all groups in the pool have reached zfs_mg_noalloc_threshold.
80 * Once all groups in the pool reach zfs_mg_noalloc_threshold then all
81 * groups are allowed to accept allocations. Gang blocks are always
82 * eligible to allocate on any metaslab group. The default value of 0 means
83 * no metaslab group will be excluded based on this criterion.
84 */
85 int zfs_mg_noalloc_threshold = 0;
86
87 /*
88 * When set will load all metaslabs when pool is first opened.
89 */
90 int metaslab_debug_load = 0;
91
92 /*
93 * When set will prevent metaslabs from being unloaded.
94 */
95 int metaslab_debug_unload = 0;
96
97 /*
98 * Minimum size which forces the dynamic allocator to change
99 * it's allocation strategy. Once the space map cannot satisfy
100 * an allocation of this size then it switches to using more
101 * aggressive strategy (i.e search by size rather than offset).
102 */
103 uint64_t metaslab_df_alloc_threshold = SPA_MAXBLOCKSIZE;
104
105 /*
106 * The minimum free space, in percent, which must be available
107 * in a space map to continue allocations in a first-fit fashion.
108 * Once the space_map's free space drops below this level we dynamically
109 * switch to using best-fit allocations.
110 */
111 int metaslab_df_free_pct = 4;
112
113 /*
114 * A metaslab is considered "free" if it contains a contiguous
115 * segment which is greater than metaslab_min_alloc_size.
116 */
117 uint64_t metaslab_min_alloc_size = DMU_MAX_ACCESS;
118
119 /*
120 * Percentage of all cpus that can be used by the metaslab taskq.
121 */
122 int metaslab_load_pct = 50;
123
124 /*
125 * Determines how many txgs a metaslab may remain loaded without having any
126 * allocations from it. As long as a metaslab continues to be used we will
127 * keep it loaded.
128 */
129 int metaslab_unload_delay = TXG_SIZE * 2;
130
131 /*
132 * Should we be willing to write data to degraded vdevs?
133 */
134 boolean_t zfs_write_to_degraded = B_FALSE;
135
136 /*
137 * Max number of metaslabs per group to preload.
138 */
139 int metaslab_preload_limit = SPA_DVAS_PER_BP;
140
141 /*
142 * Enable/disable preloading of metaslab.
143 */
144 boolean_t metaslab_preload_enabled = B_TRUE;
145
146 /*
147 * Enable/disable additional weight factor for each metaslab.
148 */
149 boolean_t metaslab_weight_factor_enable = B_FALSE;
150
151
152 /*
153 * ==========================================================================
154 * Metaslab classes
155 * ==========================================================================
156 */
157 metaslab_class_t *
158 metaslab_class_create(spa_t *spa, metaslab_ops_t *ops)
159 {
160 metaslab_class_t *mc;
161
162 mc = kmem_zalloc(sizeof (metaslab_class_t), KM_SLEEP);
163
164 mc->mc_spa = spa;
165 mc->mc_rotor = NULL;
166 mc->mc_ops = ops;
167
168 return (mc);
169 }
170
171 void
172 metaslab_class_destroy(metaslab_class_t *mc)
173 {
174 ASSERT(mc->mc_rotor == NULL);
175 ASSERT(mc->mc_alloc == 0);
176 ASSERT(mc->mc_deferred == 0);
177 ASSERT(mc->mc_space == 0);
178 ASSERT(mc->mc_dspace == 0);
179
180 kmem_free(mc, sizeof (metaslab_class_t));
181 }
182
183 int
184 metaslab_class_validate(metaslab_class_t *mc)
185 {
186 metaslab_group_t *mg;
187 vdev_t *vd;
188
189 /*
190 * Must hold one of the spa_config locks.
191 */
192 ASSERT(spa_config_held(mc->mc_spa, SCL_ALL, RW_READER) ||
193 spa_config_held(mc->mc_spa, SCL_ALL, RW_WRITER));
194
195 if ((mg = mc->mc_rotor) == NULL)
196 return (0);
197
198 do {
199 vd = mg->mg_vd;
200 ASSERT(vd->vdev_mg != NULL);
201 ASSERT3P(vd->vdev_top, ==, vd);
202 ASSERT3P(mg->mg_class, ==, mc);
203 ASSERT3P(vd->vdev_ops, !=, &vdev_hole_ops);
204 } while ((mg = mg->mg_next) != mc->mc_rotor);
205
206 return (0);
207 }
208
209 void
210 metaslab_class_space_update(metaslab_class_t *mc, int64_t alloc_delta,
211 int64_t defer_delta, int64_t space_delta, int64_t dspace_delta)
212 {
213 atomic_add_64(&mc->mc_alloc, alloc_delta);
214 atomic_add_64(&mc->mc_deferred, defer_delta);
215 atomic_add_64(&mc->mc_space, space_delta);
216 atomic_add_64(&mc->mc_dspace, dspace_delta);
217 }
218
219 uint64_t
220 metaslab_class_get_alloc(metaslab_class_t *mc)
221 {
222 return (mc->mc_alloc);
223 }
224
225 uint64_t
226 metaslab_class_get_deferred(metaslab_class_t *mc)
227 {
228 return (mc->mc_deferred);
229 }
230
231 uint64_t
232 metaslab_class_get_space(metaslab_class_t *mc)
233 {
234 return (mc->mc_space);
235 }
236
237 uint64_t
238 metaslab_class_get_dspace(metaslab_class_t *mc)
239 {
240 return (spa_deflate(mc->mc_spa) ? mc->mc_dspace : mc->mc_space);
241 }
242
243 /*
244 * ==========================================================================
245 * Metaslab groups
246 * ==========================================================================
247 */
248 static int
249 metaslab_compare(const void *x1, const void *x2)
250 {
251 const metaslab_t *m1 = x1;
252 const metaslab_t *m2 = x2;
253
254 if (m1->ms_weight < m2->ms_weight)
255 return (1);
256 if (m1->ms_weight > m2->ms_weight)
257 return (-1);
258
259 /*
260 * If the weights are identical, use the offset to force uniqueness.
261 */
262 if (m1->ms_start < m2->ms_start)
263 return (-1);
264 if (m1->ms_start > m2->ms_start)
265 return (1);
266
267 ASSERT3P(m1, ==, m2);
268
269 return (0);
270 }
271
272 /*
273 * Update the allocatable flag and the metaslab group's capacity.
274 * The allocatable flag is set to true if the capacity is below
275 * the zfs_mg_noalloc_threshold. If a metaslab group transitions
276 * from allocatable to non-allocatable or vice versa then the metaslab
277 * group's class is updated to reflect the transition.
278 */
279 static void
280 metaslab_group_alloc_update(metaslab_group_t *mg)
281 {
282 vdev_t *vd = mg->mg_vd;
283 metaslab_class_t *mc = mg->mg_class;
284 vdev_stat_t *vs = &vd->vdev_stat;
285 boolean_t was_allocatable;
286
287 ASSERT(vd == vd->vdev_top);
288
289 mutex_enter(&mg->mg_lock);
290 was_allocatable = mg->mg_allocatable;
291
292 mg->mg_free_capacity = ((vs->vs_space - vs->vs_alloc) * 100) /
293 (vs->vs_space + 1);
294
295 mg->mg_allocatable = (mg->mg_free_capacity > zfs_mg_noalloc_threshold);
296
297 /*
298 * The mc_alloc_groups maintains a count of the number of
299 * groups in this metaslab class that are still above the
300 * zfs_mg_noalloc_threshold. This is used by the allocating
301 * threads to determine if they should avoid allocations to
302 * a given group. The allocator will avoid allocations to a group
303 * if that group has reached or is below the zfs_mg_noalloc_threshold
304 * and there are still other groups that are above the threshold.
305 * When a group transitions from allocatable to non-allocatable or
306 * vice versa we update the metaslab class to reflect that change.
307 * When the mc_alloc_groups value drops to 0 that means that all
308 * groups have reached the zfs_mg_noalloc_threshold making all groups
309 * eligible for allocations. This effectively means that all devices
310 * are balanced again.
311 */
312 if (was_allocatable && !mg->mg_allocatable)
313 mc->mc_alloc_groups--;
314 else if (!was_allocatable && mg->mg_allocatable)
315 mc->mc_alloc_groups++;
316 mutex_exit(&mg->mg_lock);
317 }
318
319 metaslab_group_t *
320 metaslab_group_create(metaslab_class_t *mc, vdev_t *vd)
321 {
322 metaslab_group_t *mg;
323
324 mg = kmem_zalloc(sizeof (metaslab_group_t), KM_SLEEP);
325 mutex_init(&mg->mg_lock, NULL, MUTEX_DEFAULT, NULL);
326 avl_create(&mg->mg_metaslab_tree, metaslab_compare,
327 sizeof (metaslab_t), offsetof(struct metaslab, ms_group_node));
328 mg->mg_vd = vd;
329 mg->mg_class = mc;
330 mg->mg_activation_count = 0;
331
332 mg->mg_taskq = taskq_create("metaslab_group_tasksq", metaslab_load_pct,
333 minclsyspri, 10, INT_MAX, TASKQ_THREADS_CPU_PCT);
334
335 return (mg);
336 }
337
338 void
339 metaslab_group_destroy(metaslab_group_t *mg)
340 {
341 ASSERT(mg->mg_prev == NULL);
342 ASSERT(mg->mg_next == NULL);
343 /*
344 * We may have gone below zero with the activation count
345 * either because we never activated in the first place or
346 * because we're done, and possibly removing the vdev.
347 */
348 ASSERT(mg->mg_activation_count <= 0);
349
350 avl_destroy(&mg->mg_metaslab_tree);
351 mutex_destroy(&mg->mg_lock);
352 kmem_free(mg, sizeof (metaslab_group_t));
353 }
354
355 void
356 metaslab_group_activate(metaslab_group_t *mg)
357 {
358 metaslab_class_t *mc = mg->mg_class;
359 metaslab_group_t *mgprev, *mgnext;
360
361 ASSERT(spa_config_held(mc->mc_spa, SCL_ALLOC, RW_WRITER));
362
363 ASSERT(mc->mc_rotor != mg);
364 ASSERT(mg->mg_prev == NULL);
365 ASSERT(mg->mg_next == NULL);
366 ASSERT(mg->mg_activation_count <= 0);
367
368 if (++mg->mg_activation_count <= 0)
369 return;
370
371 mg->mg_aliquot = metaslab_aliquot * MAX(1, mg->mg_vd->vdev_children);
372 metaslab_group_alloc_update(mg);
373
374 if ((mgprev = mc->mc_rotor) == NULL) {
375 mg->mg_prev = mg;
376 mg->mg_next = mg;
377 } else {
378 mgnext = mgprev->mg_next;
379 mg->mg_prev = mgprev;
380 mg->mg_next = mgnext;
381 mgprev->mg_next = mg;
382 mgnext->mg_prev = mg;
383 }
384 mc->mc_rotor = mg;
385 }
386
387 void
388 metaslab_group_passivate(metaslab_group_t *mg)
389 {
390 metaslab_class_t *mc = mg->mg_class;
391 metaslab_group_t *mgprev, *mgnext;
392
393 ASSERT(spa_config_held(mc->mc_spa, SCL_ALLOC, RW_WRITER));
394
395 if (--mg->mg_activation_count != 0) {
396 ASSERT(mc->mc_rotor != mg);
397 ASSERT(mg->mg_prev == NULL);
398 ASSERT(mg->mg_next == NULL);
399 ASSERT(mg->mg_activation_count < 0);
400 return;
401 }
402
403 taskq_wait(mg->mg_taskq);
404
405 mgprev = mg->mg_prev;
406 mgnext = mg->mg_next;
407
408 if (mg == mgnext) {
409 mc->mc_rotor = NULL;
410 } else {
411 mc->mc_rotor = mgnext;
412 mgprev->mg_next = mgnext;
413 mgnext->mg_prev = mgprev;
414 }
415
416 mg->mg_prev = NULL;
417 mg->mg_next = NULL;
418 }
419
420 static void
421 metaslab_group_add(metaslab_group_t *mg, metaslab_t *msp)
422 {
423 mutex_enter(&mg->mg_lock);
424 ASSERT(msp->ms_group == NULL);
425 msp->ms_group = mg;
426 msp->ms_weight = 0;
427 avl_add(&mg->mg_metaslab_tree, msp);
428 mutex_exit(&mg->mg_lock);
429 }
430
431 static void
432 metaslab_group_remove(metaslab_group_t *mg, metaslab_t *msp)
433 {
434 mutex_enter(&mg->mg_lock);
435 ASSERT(msp->ms_group == mg);
436 avl_remove(&mg->mg_metaslab_tree, msp);
437 msp->ms_group = NULL;
438 mutex_exit(&mg->mg_lock);
439 }
440
441 static void
442 metaslab_group_sort(metaslab_group_t *mg, metaslab_t *msp, uint64_t weight)
443 {
444 /*
445 * Although in principle the weight can be any value, in
446 * practice we do not use values in the range [1, 510].
447 */
448 ASSERT(weight >= SPA_MINBLOCKSIZE-1 || weight == 0);
449 ASSERT(MUTEX_HELD(&msp->ms_lock));
450
451 mutex_enter(&mg->mg_lock);
452 ASSERT(msp->ms_group == mg);
453 avl_remove(&mg->mg_metaslab_tree, msp);
454 msp->ms_weight = weight;
455 avl_add(&mg->mg_metaslab_tree, msp);
456 mutex_exit(&mg->mg_lock);
457 }
458
459 /*
460 * Determine if a given metaslab group should skip allocations. A metaslab
461 * group should avoid allocations if its used capacity has crossed the
462 * zfs_mg_noalloc_threshold and there is at least one metaslab group
463 * that can still handle allocations.
464 */
465 static boolean_t
466 metaslab_group_allocatable(metaslab_group_t *mg)
467 {
468 vdev_t *vd = mg->mg_vd;
469 spa_t *spa = vd->vdev_spa;
470 metaslab_class_t *mc = mg->mg_class;
471
472 /*
473 * A metaslab group is considered allocatable if its free capacity
474 * is greater than the set value of zfs_mg_noalloc_threshold, it's
475 * associated with a slog, or there are no other metaslab groups
476 * with free capacity greater than zfs_mg_noalloc_threshold.
477 */
478 return (mg->mg_free_capacity > zfs_mg_noalloc_threshold ||
479 mc != spa_normal_class(spa) || mc->mc_alloc_groups == 0);
480 }
481
482 /*
483 * ==========================================================================
484 * Range tree callbacks
485 * ==========================================================================
486 */
487
488 /*
489 * Comparison function for the private size-ordered tree. Tree is sorted
490 * by size, larger sizes at the end of the tree.
491 */
492 static int
493 metaslab_rangesize_compare(const void *x1, const void *x2)
494 {
495 const range_seg_t *r1 = x1;
496 const range_seg_t *r2 = x2;
497 uint64_t rs_size1 = r1->rs_end - r1->rs_start;
498 uint64_t rs_size2 = r2->rs_end - r2->rs_start;
499
500 if (rs_size1 < rs_size2)
501 return (-1);
502 if (rs_size1 > rs_size2)
503 return (1);
504
505 if (r1->rs_start < r2->rs_start)
506 return (-1);
507
508 if (r1->rs_start > r2->rs_start)
509 return (1);
510
511 return (0);
512 }
513
514 /*
515 * Create any block allocator specific components. The current allocators
516 * rely on using both a size-ordered range_tree_t and an array of uint64_t's.
517 */
518 static void
519 metaslab_rt_create(range_tree_t *rt, void *arg)
520 {
521 metaslab_t *msp = arg;
522
523 ASSERT3P(rt->rt_arg, ==, msp);
524 ASSERT(msp->ms_tree == NULL);
525
526 avl_create(&msp->ms_size_tree, metaslab_rangesize_compare,
527 sizeof (range_seg_t), offsetof(range_seg_t, rs_pp_node));
528 }
529
530 /*
531 * Destroy the block allocator specific components.
532 */
533 static void
534 metaslab_rt_destroy(range_tree_t *rt, void *arg)
535 {
536 metaslab_t *msp = arg;
537
538 ASSERT3P(rt->rt_arg, ==, msp);
539 ASSERT3P(msp->ms_tree, ==, rt);
540 ASSERT0(avl_numnodes(&msp->ms_size_tree));
541
542 avl_destroy(&msp->ms_size_tree);
543 }
544
545 static void
546 metaslab_rt_add(range_tree_t *rt, range_seg_t *rs, void *arg)
547 {
548 metaslab_t *msp = arg;
549
550 ASSERT3P(rt->rt_arg, ==, msp);
551 ASSERT3P(msp->ms_tree, ==, rt);
552 VERIFY(!msp->ms_condensing);
553 avl_add(&msp->ms_size_tree, rs);
554 }
555
556 static void
557 metaslab_rt_remove(range_tree_t *rt, range_seg_t *rs, void *arg)
558 {
559 metaslab_t *msp = arg;
560
561 ASSERT3P(rt->rt_arg, ==, msp);
562 ASSERT3P(msp->ms_tree, ==, rt);
563 VERIFY(!msp->ms_condensing);
564 avl_remove(&msp->ms_size_tree, rs);
565 }
566
567 static void
568 metaslab_rt_vacate(range_tree_t *rt, void *arg)
569 {
570 metaslab_t *msp = arg;
571
572 ASSERT3P(rt->rt_arg, ==, msp);
573 ASSERT3P(msp->ms_tree, ==, rt);
574
575 /*
576 * Normally one would walk the tree freeing nodes along the way.
577 * Since the nodes are shared with the range trees we can avoid
578 * walking all nodes and just reinitialize the avl tree. The nodes
579 * will be freed by the range tree, so we don't want to free them here.
580 */
581 avl_create(&msp->ms_size_tree, metaslab_rangesize_compare,
582 sizeof (range_seg_t), offsetof(range_seg_t, rs_pp_node));
583 }
584
585 static range_tree_ops_t metaslab_rt_ops = {
586 metaslab_rt_create,
587 metaslab_rt_destroy,
588 metaslab_rt_add,
589 metaslab_rt_remove,
590 metaslab_rt_vacate
591 };
592
593 /*
594 * ==========================================================================
595 * Metaslab block operations
596 * ==========================================================================
597 */
598
599 /*
600 * Return the maximum contiguous segment within the metaslab.
601 */
602 uint64_t
603 metaslab_block_maxsize(metaslab_t *msp)
604 {
605 avl_tree_t *t = &msp->ms_size_tree;
606 range_seg_t *rs;
607
608 if (t == NULL || (rs = avl_last(t)) == NULL)
609 return (0ULL);
610
611 return (rs->rs_end - rs->rs_start);
612 }
613
614 uint64_t
615 metaslab_block_alloc(metaslab_t *msp, uint64_t size)
616 {
617 uint64_t start;
618 range_tree_t *rt = msp->ms_tree;
619
620 VERIFY(!msp->ms_condensing);
621
622 start = msp->ms_ops->msop_alloc(msp, size);
623 if (start != -1ULL) {
624 vdev_t *vd = msp->ms_group->mg_vd;
625
626 VERIFY0(P2PHASE(start, 1ULL << vd->vdev_ashift));
627 VERIFY0(P2PHASE(size, 1ULL << vd->vdev_ashift));
628 VERIFY3U(range_tree_space(rt) - size, <=, msp->ms_size);
629 range_tree_remove(rt, start, size);
630 }
631 return (start);
632 }
633
634 /*
635 * ==========================================================================
636 * Common allocator routines
637 * ==========================================================================
638 */
639
640 /*
641 * This is a helper function that can be used by the allocator to find
642 * a suitable block to allocate. This will search the specified AVL
643 * tree looking for a block that matches the specified criteria.
644 */
645 static uint64_t
646 metaslab_block_picker(avl_tree_t *t, uint64_t *cursor, uint64_t size,
647 uint64_t align)
648 {
649 range_seg_t *rs, rsearch;
650 avl_index_t where;
651
652 rsearch.rs_start = *cursor;
653 rsearch.rs_end = *cursor + size;
654
655 rs = avl_find(t, &rsearch, &where);
656 if (rs == NULL)
657 rs = avl_nearest(t, where, AVL_AFTER);
658
659 while (rs != NULL) {
660 uint64_t offset = P2ROUNDUP(rs->rs_start, align);
661
662 if (offset + size <= rs->rs_end) {
663 *cursor = offset + size;
664 return (offset);
665 }
666 rs = AVL_NEXT(t, rs);
667 }
668
669 /*
670 * If we know we've searched the whole map (*cursor == 0), give up.
671 * Otherwise, reset the cursor to the beginning and try again.
672 */
673 if (*cursor == 0)
674 return (-1ULL);
675
676 *cursor = 0;
677 return (metaslab_block_picker(t, cursor, size, align));
678 }
679
680 /*
681 * ==========================================================================
682 * The first-fit block allocator
683 * ==========================================================================
684 */
685 static uint64_t
686 metaslab_ff_alloc(metaslab_t *msp, uint64_t size)
687 {
688 /*
689 * Find the largest power of 2 block size that evenly divides the
690 * requested size. This is used to try to allocate blocks with similar
691 * alignment from the same area of the metaslab (i.e. same cursor
692 * bucket) but it does not guarantee that other allocations sizes
693 * may exist in the same region.
694 */
695 uint64_t align = size & -size;
696 uint64_t *cursor = &msp->ms_lbas[highbit(align) - 1];
697 avl_tree_t *t = &msp->ms_tree->rt_root;
698
699 return (metaslab_block_picker(t, cursor, size, align));
700 }
701
702 /* ARGSUSED */
703 static boolean_t
704 metaslab_ff_fragmented(metaslab_t *msp)
705 {
706 return (B_TRUE);
707 }
708
709 static metaslab_ops_t metaslab_ff_ops = {
710 metaslab_ff_alloc,
711 metaslab_ff_fragmented
712 };
713
714 /*
715 * ==========================================================================
716 * Dynamic block allocator -
717 * Uses the first fit allocation scheme until space get low and then
718 * adjusts to a best fit allocation method. Uses metaslab_df_alloc_threshold
719 * and metaslab_df_free_pct to determine when to switch the allocation scheme.
720 * ==========================================================================
721 */
722 static uint64_t
723 metaslab_df_alloc(metaslab_t *msp, uint64_t size)
724 {
725 /*
726 * Find the largest power of 2 block size that evenly divides the
727 * requested size. This is used to try to allocate blocks with similar
728 * alignment from the same area of the metaslab (i.e. same cursor
729 * bucket) but it does not guarantee that other allocations sizes
730 * may exist in the same region.
731 */
732 uint64_t align = size & -size;
733 uint64_t *cursor = &msp->ms_lbas[highbit(align) - 1];
734 range_tree_t *rt = msp->ms_tree;
735 avl_tree_t *t = &rt->rt_root;
736 uint64_t max_size = metaslab_block_maxsize(msp);
737 int free_pct = range_tree_space(rt) * 100 / msp->ms_size;
738
739 ASSERT(MUTEX_HELD(&msp->ms_lock));
740 ASSERT3U(avl_numnodes(t), ==, avl_numnodes(&msp->ms_size_tree));
741
742 if (max_size < size)
743 return (-1ULL);
744
745 /*
746 * If we're running low on space switch to using the size
747 * sorted AVL tree (best-fit).
748 */
749 if (max_size < metaslab_df_alloc_threshold ||
750 free_pct < metaslab_df_free_pct) {
751 t = &msp->ms_size_tree;
752 *cursor = 0;
753 }
754
755 return (metaslab_block_picker(t, cursor, size, 1ULL));
756 }
757
758 static boolean_t
759 metaslab_df_fragmented(metaslab_t *msp)
760 {
761 range_tree_t *rt = msp->ms_tree;
762 uint64_t max_size = metaslab_block_maxsize(msp);
763 int free_pct = range_tree_space(rt) * 100 / msp->ms_size;
764
765 if (max_size >= metaslab_df_alloc_threshold &&
766 free_pct >= metaslab_df_free_pct)
767 return (B_FALSE);
768
769 return (B_TRUE);
770 }
771
772 static metaslab_ops_t metaslab_df_ops = {
773 metaslab_df_alloc,
774 metaslab_df_fragmented
775 };
776
777 /*
778 * ==========================================================================
779 * Cursor fit block allocator -
780 * Select the largest region in the metaslab, set the cursor to the beginning
781 * of the range and the cursor_end to the end of the range. As allocations
782 * are made advance the cursor. Continue allocating from the cursor until
783 * the range is exhausted and then find a new range.
784 * ==========================================================================
785 */
786 static uint64_t
787 metaslab_cf_alloc(metaslab_t *msp, uint64_t size)
788 {
789 range_tree_t *rt = msp->ms_tree;
790 avl_tree_t *t = &msp->ms_size_tree;
791 uint64_t *cursor = &msp->ms_lbas[0];
792 uint64_t *cursor_end = &msp->ms_lbas[1];
793 uint64_t offset = 0;
794
795 ASSERT(MUTEX_HELD(&msp->ms_lock));
796 ASSERT3U(avl_numnodes(t), ==, avl_numnodes(&rt->rt_root));
797
798 ASSERT3U(*cursor_end, >=, *cursor);
799
800 if ((*cursor + size) > *cursor_end) {
801 range_seg_t *rs;
802
803 rs = avl_last(&msp->ms_size_tree);
804 if (rs == NULL || (rs->rs_end - rs->rs_start) < size)
805 return (-1ULL);
806
807 *cursor = rs->rs_start;
808 *cursor_end = rs->rs_end;
809 }
810
811 offset = *cursor;
812 *cursor += size;
813
814 return (offset);
815 }
816
817 static boolean_t
818 metaslab_cf_fragmented(metaslab_t *msp)
819 {
820 return (metaslab_block_maxsize(msp) < metaslab_min_alloc_size);
821 }
822
823 static metaslab_ops_t metaslab_cf_ops = {
824 metaslab_cf_alloc,
825 metaslab_cf_fragmented
826 };
827
828 /*
829 * ==========================================================================
830 * New dynamic fit allocator -
831 * Select a region that is large enough to allocate 2^metaslab_ndf_clump_shift
832 * contiguous blocks. If no region is found then just use the largest segment
833 * that remains.
834 * ==========================================================================
835 */
836
837 /*
838 * Determines desired number of contiguous blocks (2^metaslab_ndf_clump_shift)
839 * to request from the allocator.
840 */
841 uint64_t metaslab_ndf_clump_shift = 4;
842
843 static uint64_t
844 metaslab_ndf_alloc(metaslab_t *msp, uint64_t size)
845 {
846 avl_tree_t *t = &msp->ms_tree->rt_root;
847 avl_index_t where;
848 range_seg_t *rs, rsearch;
849 uint64_t hbit = highbit(size);
850 uint64_t *cursor = &msp->ms_lbas[hbit - 1];
851 uint64_t max_size = metaslab_block_maxsize(msp);
852
853 ASSERT(MUTEX_HELD(&msp->ms_lock));
854 ASSERT3U(avl_numnodes(t), ==, avl_numnodes(&msp->ms_size_tree));
855
856 if (max_size < size)
857 return (-1ULL);
858
859 rsearch.rs_start = *cursor;
860 rsearch.rs_end = *cursor + size;
861
862 rs = avl_find(t, &rsearch, &where);
863 if (rs == NULL || (rs->rs_end - rs->rs_start) < size) {
864 t = &msp->ms_size_tree;
865
866 rsearch.rs_start = 0;
867 rsearch.rs_end = MIN(max_size,
868 1ULL << (hbit + metaslab_ndf_clump_shift));
869 rs = avl_find(t, &rsearch, &where);
870 if (rs == NULL)
871 rs = avl_nearest(t, where, AVL_AFTER);
872 ASSERT(rs != NULL);
873 }
874
875 if ((rs->rs_end - rs->rs_start) >= size) {
876 *cursor = rs->rs_start + size;
877 return (rs->rs_start);
878 }
879 return (-1ULL);
880 }
881
882 static boolean_t
883 metaslab_ndf_fragmented(metaslab_t *msp)
884 {
885 return (metaslab_block_maxsize(msp) <=
886 (metaslab_min_alloc_size << metaslab_ndf_clump_shift));
887 }
888
889 static metaslab_ops_t metaslab_ndf_ops = {
890 metaslab_ndf_alloc,
891 metaslab_ndf_fragmented
892 };
893
894 metaslab_ops_t *zfs_metaslab_ops = &metaslab_df_ops;
895
896 /*
897 * ==========================================================================
898 * Metaslabs
899 * ==========================================================================
900 */
901
902 /*
903 * Wait for any in-progress metaslab loads to complete.
904 */
905 void
906 metaslab_load_wait(metaslab_t *msp)
907 {
908 ASSERT(MUTEX_HELD(&msp->ms_lock));
909
910 while (msp->ms_loading) {
911 ASSERT(!msp->ms_loaded);
912 cv_wait(&msp->ms_load_cv, &msp->ms_lock);
913 }
914 }
915
916 int
917 metaslab_load(metaslab_t *msp)
918 {
919 int error = 0;
920
921 ASSERT(MUTEX_HELD(&msp->ms_lock));
922 ASSERT(!msp->ms_loaded);
923 ASSERT(!msp->ms_loading);
924
925 msp->ms_loading = B_TRUE;
926
927 /*
928 * If the space map has not been allocated yet, then treat
929 * all the space in the metaslab as free and add it to the
930 * ms_tree.
931 */
932 if (msp->ms_sm != NULL)
933 error = space_map_load(msp->ms_sm, msp->ms_tree, SM_FREE);
934 else
935 range_tree_add(msp->ms_tree, msp->ms_start, msp->ms_size);
936
937 msp->ms_loaded = (error == 0);
938 msp->ms_loading = B_FALSE;
939
940 if (msp->ms_loaded) {
941 for (int t = 0; t < TXG_DEFER_SIZE; t++) {
942 range_tree_walk(msp->ms_defertree[t],
943 range_tree_remove, msp->ms_tree);
944 }
945 }
946 cv_broadcast(&msp->ms_load_cv);
947 return (error);
948 }
949
950 void
951 metaslab_unload(metaslab_t *msp)
952 {
953 ASSERT(MUTEX_HELD(&msp->ms_lock));
954 range_tree_vacate(msp->ms_tree, NULL, NULL);
955 msp->ms_loaded = B_FALSE;
956 msp->ms_weight &= ~METASLAB_ACTIVE_MASK;
957 }
958
959 metaslab_t *
960 metaslab_init(metaslab_group_t *mg, uint64_t id, uint64_t object, uint64_t txg)
961 {
962 vdev_t *vd = mg->mg_vd;
963 objset_t *mos = vd->vdev_spa->spa_meta_objset;
964 metaslab_t *msp;
965
966 msp = kmem_zalloc(sizeof (metaslab_t), KM_SLEEP);
967 mutex_init(&msp->ms_lock, NULL, MUTEX_DEFAULT, NULL);
968 cv_init(&msp->ms_load_cv, NULL, CV_DEFAULT, NULL);
969 msp->ms_id = id;
970 msp->ms_start = id << vd->vdev_ms_shift;
971 msp->ms_size = 1ULL << vd->vdev_ms_shift;
972
973 /*
974 * We only open space map objects that already exist. All others
975 * will be opened when we finally allocate an object for it.
976 */
977 if (object != 0) {
978 VERIFY0(space_map_open(&msp->ms_sm, mos, object, msp->ms_start,
979 msp->ms_size, vd->vdev_ashift, &msp->ms_lock));
980 ASSERT(msp->ms_sm != NULL);
981 }
982
983 /*
984 * We create the main range tree here, but we don't create the
985 * alloctree and freetree until metaslab_sync_done(). This serves
986 * two purposes: it allows metaslab_sync_done() to detect the
987 * addition of new space; and for debugging, it ensures that we'd
988 * data fault on any attempt to use this metaslab before it's ready.
989 */
990 msp->ms_tree = range_tree_create(&metaslab_rt_ops, msp, &msp->ms_lock);
991 metaslab_group_add(mg, msp);
992
993 msp->ms_ops = mg->mg_class->mc_ops;
994
995 /*
996 * If we're opening an existing pool (txg == 0) or creating
997 * a new one (txg == TXG_INITIAL), all space is available now.
998 * If we're adding space to an existing pool, the new space
999 * does not become available until after this txg has synced.
1000 */
1001 if (txg <= TXG_INITIAL)
1002 metaslab_sync_done(msp, 0);
1003
1004 /*
1005 * If metaslab_debug_load is set and we're initializing a metaslab
1006 * that has an allocated space_map object then load the its space
1007 * map so that can verify frees.
1008 */
1009 if (metaslab_debug_load && msp->ms_sm != NULL) {
1010 mutex_enter(&msp->ms_lock);
1011 VERIFY0(metaslab_load(msp));
1012 mutex_exit(&msp->ms_lock);
1013 }
1014
1015 if (txg != 0) {
1016 vdev_dirty(vd, 0, NULL, txg);
1017 vdev_dirty(vd, VDD_METASLAB, msp, txg);
1018 }
1019
1020 return (msp);
1021 }
1022
1023 void
1024 metaslab_fini(metaslab_t *msp)
1025 {
1026 metaslab_group_t *mg = msp->ms_group;
1027
1028 metaslab_group_remove(mg, msp);
1029
1030 mutex_enter(&msp->ms_lock);
1031
1032 VERIFY(msp->ms_group == NULL);
1033 vdev_space_update(mg->mg_vd, -space_map_allocated(msp->ms_sm),
1034 0, -msp->ms_size);
1035 space_map_close(msp->ms_sm);
1036
1037 metaslab_unload(msp);
1038 range_tree_destroy(msp->ms_tree);
1039
1040 for (int t = 0; t < TXG_SIZE; t++) {
1041 range_tree_destroy(msp->ms_alloctree[t]);
1042 range_tree_destroy(msp->ms_freetree[t]);
1043 }
1044
1045 for (int t = 0; t < TXG_DEFER_SIZE; t++) {
1046 range_tree_destroy(msp->ms_defertree[t]);
1047 }
1048
1049 ASSERT0(msp->ms_deferspace);
1050
1051 mutex_exit(&msp->ms_lock);
1052 cv_destroy(&msp->ms_load_cv);
1053 mutex_destroy(&msp->ms_lock);
1054
1055 kmem_free(msp, sizeof (metaslab_t));
1056 }
1057
1058 /*
1059 * Apply a weighting factor based on the histogram information for this
1060 * metaslab. The current weighting factor is somewhat arbitrary and requires
1061 * additional investigation. The implementation provides a measure of
1062 * "weighted" free space and gives a higher weighting for larger contiguous
1063 * regions. The weighting factor is determined by counting the number of
1064 * sm_shift sectors that exist in each region represented by the histogram.
1065 * That value is then multiplied by the power of 2 exponent and the sm_shift
1066 * value.
1067 *
1068 * For example, assume the 2^21 histogram bucket has 4 2MB regions and the
1069 * metaslab has an sm_shift value of 9 (512B):
1070 *
1071 * 1) calculate the number of sm_shift sectors in the region:
1072 * 2^21 / 2^9 = 2^12 = 4096 * 4 (number of regions) = 16384
1073 * 2) multiply by the power of 2 exponent and the sm_shift value:
1074 * 16384 * 21 * 9 = 3096576
1075 * This value will be added to the weighting of the metaslab.
1076 */
1077 static uint64_t
1078 metaslab_weight_factor(metaslab_t *msp)
1079 {
1080 uint64_t factor = 0;
1081 uint64_t sectors;
1082 int i;
1083
1084 /*
1085 * A null space map means that the entire metaslab is free,
1086 * calculate a weight factor that spans the entire size of the
1087 * metaslab.
1088 */
1089 if (msp->ms_sm == NULL) {
1090 vdev_t *vd = msp->ms_group->mg_vd;
1091
1092 i = highbit(msp->ms_size) - 1;
1093 sectors = msp->ms_size >> vd->vdev_ashift;
1094 return (sectors * i * vd->vdev_ashift);
1095 }
1096
1097 if (msp->ms_sm->sm_dbuf->db_size != sizeof (space_map_phys_t))
1098 return (0);
1099
1100 for (i = 0; i < SPACE_MAP_HISTOGRAM_SIZE(msp->ms_sm); i++) {
1101 if (msp->ms_sm->sm_phys->smp_histogram[i] == 0)
1102 continue;
1103
1104 /*
1105 * Determine the number of sm_shift sectors in the region
1106 * indicated by the histogram. For example, given an
1107 * sm_shift value of 9 (512 bytes) and i = 4 then we know
1108 * that we're looking at an 8K region in the histogram
1109 * (i.e. 9 + 4 = 13, 2^13 = 8192). To figure out the
1110 * number of sm_shift sectors (512 bytes in this example),
1111 * we would take 8192 / 512 = 16. Since the histogram
1112 * is offset by sm_shift we can simply use the value of
1113 * of i to calculate this (i.e. 2^i = 16 where i = 4).
1114 */
1115 sectors = msp->ms_sm->sm_phys->smp_histogram[i] << i;
1116 factor += (i + msp->ms_sm->sm_shift) * sectors;
1117 }
1118 return (factor * msp->ms_sm->sm_shift);
1119 }
1120
1121 static uint64_t
1122 metaslab_weight(metaslab_t *msp)
1123 {
1124 metaslab_group_t *mg = msp->ms_group;
1125 vdev_t *vd = mg->mg_vd;
1126 uint64_t weight, space;
1127
1128 ASSERT(MUTEX_HELD(&msp->ms_lock));
1129
1130 /*
1131 * This vdev is in the process of being removed so there is nothing
1132 * for us to do here.
1133 */
1134 if (vd->vdev_removing) {
1135 ASSERT0(space_map_allocated(msp->ms_sm));
1136 ASSERT0(vd->vdev_ms_shift);
1137 return (0);
1138 }
1139
1140 /*
1141 * The baseline weight is the metaslab's free space.
1142 */
1143 space = msp->ms_size - space_map_allocated(msp->ms_sm);
1144 weight = space;
1145
1146 /*
1147 * Modern disks have uniform bit density and constant angular velocity.
1148 * Therefore, the outer recording zones are faster (higher bandwidth)
1149 * than the inner zones by the ratio of outer to inner track diameter,
1150 * which is typically around 2:1. We account for this by assigning
1151 * higher weight to lower metaslabs (multiplier ranging from 2x to 1x).
1152 * In effect, this means that we'll select the metaslab with the most
1153 * free bandwidth rather than simply the one with the most free space.
1154 */
1155 weight = 2 * weight - (msp->ms_id * weight) / vd->vdev_ms_count;
1156 ASSERT(weight >= space && weight <= 2 * space);
1157
1158 msp->ms_factor = metaslab_weight_factor(msp);
1159 if (metaslab_weight_factor_enable)
1160 weight += msp->ms_factor;
1161
1162 if (msp->ms_loaded && !msp->ms_ops->msop_fragmented(msp)) {
1163 /*
1164 * If this metaslab is one we're actively using, adjust its
1165 * weight to make it preferable to any inactive metaslab so
1166 * we'll polish it off.
1167 */
1168 weight |= (msp->ms_weight & METASLAB_ACTIVE_MASK);
1169 }
1170
1171 return (weight);
1172 }
1173
1174 static int
1175 metaslab_activate(metaslab_t *msp, uint64_t activation_weight)
1176 {
1177 ASSERT(MUTEX_HELD(&msp->ms_lock));
1178
1179 if ((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0) {
1180 metaslab_load_wait(msp);
1181 if (!msp->ms_loaded) {
1182 int error = metaslab_load(msp);
1183 if (error) {
1184 metaslab_group_sort(msp->ms_group, msp, 0);
1185 return (error);
1186 }
1187 }
1188
1189 metaslab_group_sort(msp->ms_group, msp,
1190 msp->ms_weight | activation_weight);
1191 }
1192 ASSERT(msp->ms_loaded);
1193 ASSERT(msp->ms_weight & METASLAB_ACTIVE_MASK);
1194
1195 return (0);
1196 }
1197
1198 static void
1199 metaslab_passivate(metaslab_t *msp, uint64_t size)
1200 {
1201 /*
1202 * If size < SPA_MINBLOCKSIZE, then we will not allocate from
1203 * this metaslab again. In that case, it had better be empty,
1204 * or we would be leaving space on the table.
1205 */
1206 ASSERT(size >= SPA_MINBLOCKSIZE || range_tree_space(msp->ms_tree) == 0);
1207 metaslab_group_sort(msp->ms_group, msp, MIN(msp->ms_weight, size));
1208 ASSERT((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0);
1209 }
1210
1211 static void
1212 metaslab_preload(void *arg)
1213 {
1214 metaslab_t *msp = arg;
1215 spa_t *spa = msp->ms_group->mg_vd->vdev_spa;
1216
1217 mutex_enter(&msp->ms_lock);
1218 metaslab_load_wait(msp);
1219 if (!msp->ms_loaded)
1220 (void) metaslab_load(msp);
1221
1222 /*
1223 * Set the ms_access_txg value so that we don't unload it right away.
1224 */
1225 msp->ms_access_txg = spa_syncing_txg(spa) + metaslab_unload_delay + 1;
1226 mutex_exit(&msp->ms_lock);
1227 }
1228
1229 static void
1230 metaslab_group_preload(metaslab_group_t *mg)
1231 {
1232 spa_t *spa = mg->mg_vd->vdev_spa;
1233 metaslab_t *msp;
1234 avl_tree_t *t = &mg->mg_metaslab_tree;
1235 int m = 0;
1236
1237 if (spa_shutting_down(spa) || !metaslab_preload_enabled) {
1238 taskq_wait(mg->mg_taskq);
1239 return;
1240 }
1241 mutex_enter(&mg->mg_lock);
1242
1243 /*
1244 * Prefetch the next potential metaslabs
1245 */
1246 for (msp = avl_first(t); msp != NULL; msp = AVL_NEXT(t, msp)) {
1247
1248 /* If we have reached our preload limit then we're done */
1249 if (++m > metaslab_preload_limit)
1250 break;
1251
1252 VERIFY(taskq_dispatch(mg->mg_taskq, metaslab_preload,
1253 msp, TQ_SLEEP) != NULL);
1254 }
1255 mutex_exit(&mg->mg_lock);
1256 }
1257
1258 /*
1259 * Determine if the space map's on-disk footprint is past our tolerance
1260 * for inefficiency. We would like to use the following criteria to make
1261 * our decision:
1262 *
1263 * 1. The size of the space map object should not dramatically increase as a
1264 * result of writing out the free space range tree.
1265 *
1266 * 2. The minimal on-disk space map representation is zfs_condense_pct/100
1267 * times the size than the free space range tree representation
1268 * (i.e. zfs_condense_pct = 110 and in-core = 1MB, minimal = 1.1.MB).
1269 *
1270 * Checking the first condition is tricky since we don't want to walk
1271 * the entire AVL tree calculating the estimated on-disk size. Instead we
1272 * use the size-ordered range tree in the metaslab and calculate the
1273 * size required to write out the largest segment in our free tree. If the
1274 * size required to represent that segment on disk is larger than the space
1275 * map object then we avoid condensing this map.
1276 *
1277 * To determine the second criterion we use a best-case estimate and assume
1278 * each segment can be represented on-disk as a single 64-bit entry. We refer
1279 * to this best-case estimate as the space map's minimal form.
1280 */
1281 static boolean_t
1282 metaslab_should_condense(metaslab_t *msp)
1283 {
1284 space_map_t *sm = msp->ms_sm;
1285 range_seg_t *rs;
1286 uint64_t size, entries, segsz;
1287
1288 ASSERT(MUTEX_HELD(&msp->ms_lock));
1289 ASSERT(msp->ms_loaded);
1290
1291 /*
1292 * Use the ms_size_tree range tree, which is ordered by size, to
1293 * obtain the largest segment in the free tree. If the tree is empty
1294 * then we should condense the map.
1295 */
1296 rs = avl_last(&msp->ms_size_tree);
1297 if (rs == NULL)
1298 return (B_TRUE);
1299
1300 /*
1301 * Calculate the number of 64-bit entries this segment would
1302 * require when written to disk. If this single segment would be
1303 * larger on-disk than the entire current on-disk structure, then
1304 * clearly condensing will increase the on-disk structure size.
1305 */
1306 size = (rs->rs_end - rs->rs_start) >> sm->sm_shift;
1307 entries = size / (MIN(size, SM_RUN_MAX));
1308 segsz = entries * sizeof (uint64_t);
1309
1310 return (segsz <= space_map_length(msp->ms_sm) &&
1311 space_map_length(msp->ms_sm) >= (zfs_condense_pct *
1312 sizeof (uint64_t) * avl_numnodes(&msp->ms_tree->rt_root)) / 100);
1313 }
1314
1315 /*
1316 * Condense the on-disk space map representation to its minimized form.
1317 * The minimized form consists of a small number of allocations followed by
1318 * the entries of the free range tree.
1319 */
1320 static void
1321 metaslab_condense(metaslab_t *msp, uint64_t txg, dmu_tx_t *tx)
1322 {
1323 spa_t *spa = msp->ms_group->mg_vd->vdev_spa;
1324 range_tree_t *freetree = msp->ms_freetree[txg & TXG_MASK];
1325 range_tree_t *condense_tree;
1326 space_map_t *sm = msp->ms_sm;
1327
1328 ASSERT(MUTEX_HELD(&msp->ms_lock));
1329 ASSERT3U(spa_sync_pass(spa), ==, 1);
1330 ASSERT(msp->ms_loaded);
1331
1332 spa_dbgmsg(spa, "condensing: txg %llu, msp[%llu] %p, "
1333 "smp size %llu, segments %lu", txg, msp->ms_id, msp,
1334 space_map_length(msp->ms_sm), avl_numnodes(&msp->ms_tree->rt_root));
1335
1336 /*
1337 * Create an range tree that is 100% allocated. We remove segments
1338 * that have been freed in this txg, any deferred frees that exist,
1339 * and any allocation in the future. Removing segments should be
1340 * a relatively inexpensive operation since we expect these trees to
1341 * have a small number of nodes.
1342 */
1343 condense_tree = range_tree_create(NULL, NULL, &msp->ms_lock);
1344 range_tree_add(condense_tree, msp->ms_start, msp->ms_size);
1345
1346 /*
1347 * Remove what's been freed in this txg from the condense_tree.
1348 * Since we're in sync_pass 1, we know that all the frees from
1349 * this txg are in the freetree.
1350 */
1351 range_tree_walk(freetree, range_tree_remove, condense_tree);
1352
1353 for (int t = 0; t < TXG_DEFER_SIZE; t++) {
1354 range_tree_walk(msp->ms_defertree[t],
1355 range_tree_remove, condense_tree);
1356 }
1357
1358 for (int t = 1; t < TXG_CONCURRENT_STATES; t++) {
1359 range_tree_walk(msp->ms_alloctree[(txg + t) & TXG_MASK],
1360 range_tree_remove, condense_tree);
1361 }
1362
1363 /*
1364 * We're about to drop the metaslab's lock thus allowing
1365 * other consumers to change it's content. Set the
1366 * metaslab's ms_condensing flag to ensure that
1367 * allocations on this metaslab do not occur while we're
1368 * in the middle of committing it to disk. This is only critical
1369 * for the ms_tree as all other range trees use per txg
1370 * views of their content.
1371 */
1372 msp->ms_condensing = B_TRUE;
1373
1374 mutex_exit(&msp->ms_lock);
1375 space_map_truncate(sm, tx);
1376 mutex_enter(&msp->ms_lock);
1377
1378 /*
1379 * While we would ideally like to create a space_map representation
1380 * that consists only of allocation records, doing so can be
1381 * prohibitively expensive because the in-core free tree can be
1382 * large, and therefore computationally expensive to subtract
1383 * from the condense_tree. Instead we sync out two trees, a cheap
1384 * allocation only tree followed by the in-core free tree. While not
1385 * optimal, this is typically close to optimal, and much cheaper to
1386 * compute.
1387 */
1388 space_map_write(sm, condense_tree, SM_ALLOC, tx);
1389 range_tree_vacate(condense_tree, NULL, NULL);
1390 range_tree_destroy(condense_tree);
1391
1392 space_map_write(sm, msp->ms_tree, SM_FREE, tx);
1393 msp->ms_condensing = B_FALSE;
1394 }
1395
1396 /*
1397 * Write a metaslab to disk in the context of the specified transaction group.
1398 */
1399 void
1400 metaslab_sync(metaslab_t *msp, uint64_t txg)
1401 {
1402 metaslab_group_t *mg = msp->ms_group;
1403 vdev_t *vd = mg->mg_vd;
1404 spa_t *spa = vd->vdev_spa;
1405 objset_t *mos = spa_meta_objset(spa);
1406 range_tree_t *alloctree = msp->ms_alloctree[txg & TXG_MASK];
1407 range_tree_t **freetree = &msp->ms_freetree[txg & TXG_MASK];
1408 range_tree_t **freed_tree =
1409 &msp->ms_freetree[TXG_CLEAN(txg) & TXG_MASK];
1410 dmu_tx_t *tx;
1411 uint64_t object = space_map_object(msp->ms_sm);
1412
1413 ASSERT(!vd->vdev_ishole);
1414
1415 /*
1416 * This metaslab has just been added so there's no work to do now.
1417 */
1418 if (*freetree == NULL) {
1419 ASSERT3P(alloctree, ==, NULL);
1420 return;
1421 }
1422
1423 ASSERT3P(alloctree, !=, NULL);
1424 ASSERT3P(*freetree, !=, NULL);
1425 ASSERT3P(*freed_tree, !=, NULL);
1426
1427 if (range_tree_space(alloctree) == 0 &&
1428 range_tree_space(*freetree) == 0)
1429 return;
1430
1431 /*
1432 * The only state that can actually be changing concurrently with
1433 * metaslab_sync() is the metaslab's ms_tree. No other thread can
1434 * be modifying this txg's alloctree, freetree, freed_tree, or
1435 * space_map_phys_t. Therefore, we only hold ms_lock to satify
1436 * space_map ASSERTs. We drop it whenever we call into the DMU,
1437 * because the DMU can call down to us (e.g. via zio_free()) at
1438 * any time.
1439 */
1440
1441 tx = dmu_tx_create_assigned(spa_get_dsl(spa), txg);
1442
1443 if (msp->ms_sm == NULL) {
1444 uint64_t new_object;
1445
1446 new_object = space_map_alloc(mos, tx);
1447 VERIFY3U(new_object, !=, 0);
1448
1449 VERIFY0(space_map_open(&msp->ms_sm, mos, new_object,
1450 msp->ms_start, msp->ms_size, vd->vdev_ashift,
1451 &msp->ms_lock));
1452 ASSERT(msp->ms_sm != NULL);
1453 }
1454
1455 mutex_enter(&msp->ms_lock);
1456
1457 if (msp->ms_loaded && spa_sync_pass(spa) == 1 &&
1458 metaslab_should_condense(msp)) {
1459 metaslab_condense(msp, txg, tx);
1460 } else {
1461 space_map_write(msp->ms_sm, alloctree, SM_ALLOC, tx);
1462 space_map_write(msp->ms_sm, *freetree, SM_FREE, tx);
1463 }
1464
1465 range_tree_vacate(alloctree, NULL, NULL);
1466
1467 if (msp->ms_loaded) {
1468 /*
1469 * When the space map is loaded, we have an accruate
1470 * histogram in the range tree. This gives us an opportunity
1471 * to bring the space map's histogram up-to-date so we clear
1472 * it first before updating it.
1473 */
1474 space_map_histogram_clear(msp->ms_sm);
1475 space_map_histogram_add(msp->ms_sm, msp->ms_tree, tx);
1476 } else {
1477 /*
1478 * Since the space map is not loaded we simply update the
1479 * exisiting histogram with what was freed in this txg. This
1480 * means that the on-disk histogram may not have an accurate
1481 * view of the free space but it's close enough to allow
1482 * us to make allocation decisions.
1483 */
1484 space_map_histogram_add(msp->ms_sm, *freetree, tx);
1485 }
1486
1487 /*
1488 * For sync pass 1, we avoid traversing this txg's free range tree
1489 * and instead will just swap the pointers for freetree and
1490 * freed_tree. We can safely do this since the freed_tree is
1491 * guaranteed to be empty on the initial pass.
1492 */
1493 if (spa_sync_pass(spa) == 1) {
1494 range_tree_swap(freetree, freed_tree);
1495 } else {
1496 range_tree_vacate(*freetree, range_tree_add, *freed_tree);
1497 }
1498
1499 ASSERT0(range_tree_space(msp->ms_alloctree[txg & TXG_MASK]));
1500 ASSERT0(range_tree_space(msp->ms_freetree[txg & TXG_MASK]));
1501
1502 mutex_exit(&msp->ms_lock);
1503
1504 if (object != space_map_object(msp->ms_sm)) {
1505 object = space_map_object(msp->ms_sm);
1506 dmu_write(mos, vd->vdev_ms_array, sizeof (uint64_t) *
1507 msp->ms_id, sizeof (uint64_t), &object, tx);
1508 }
1509 dmu_tx_commit(tx);
1510 }
1511
1512 /*
1513 * Called after a transaction group has completely synced to mark
1514 * all of the metaslab's free space as usable.
1515 */
1516 void
1517 metaslab_sync_done(metaslab_t *msp, uint64_t txg)
1518 {
1519 metaslab_group_t *mg = msp->ms_group;
1520 vdev_t *vd = mg->mg_vd;
1521 range_tree_t **freed_tree;
1522 range_tree_t **defer_tree;
1523 int64_t alloc_delta, defer_delta;
1524
1525 ASSERT(!vd->vdev_ishole);
1526
1527 mutex_enter(&msp->ms_lock);
1528
1529 /*
1530 * If this metaslab is just becoming available, initialize its
1531 * alloctrees, freetrees, and defertree and add its capacity to
1532 * the vdev.
1533 */
1534 if (msp->ms_freetree[TXG_CLEAN(txg) & TXG_MASK] == NULL) {
1535 for (int t = 0; t < TXG_SIZE; t++) {
1536 ASSERT(msp->ms_alloctree[t] == NULL);
1537 ASSERT(msp->ms_freetree[t] == NULL);
1538
1539 msp->ms_alloctree[t] = range_tree_create(NULL, msp,
1540 &msp->ms_lock);
1541 msp->ms_freetree[t] = range_tree_create(NULL, msp,
1542 &msp->ms_lock);
1543 }
1544
1545 for (int t = 0; t < TXG_DEFER_SIZE; t++) {
1546 ASSERT(msp->ms_defertree[t] == NULL);
1547
1548 msp->ms_defertree[t] = range_tree_create(NULL, msp,
1549 &msp->ms_lock);
1550 }
1551
1552 vdev_space_update(vd, 0, 0, msp->ms_size);
1553 }
1554
1555 freed_tree = &msp->ms_freetree[TXG_CLEAN(txg) & TXG_MASK];
1556 defer_tree = &msp->ms_defertree[txg % TXG_DEFER_SIZE];
1557
1558 alloc_delta = space_map_alloc_delta(msp->ms_sm);
1559 defer_delta = range_tree_space(*freed_tree) -
1560 range_tree_space(*defer_tree);
1561
1562 vdev_space_update(vd, alloc_delta + defer_delta, defer_delta, 0);
1563
1564 ASSERT0(range_tree_space(msp->ms_alloctree[txg & TXG_MASK]));
1565 ASSERT0(range_tree_space(msp->ms_freetree[txg & TXG_MASK]));
1566
1567 /*
1568 * If there's a metaslab_load() in progress, wait for it to complete
1569 * so that we have a consistent view of the in-core space map.
1570 */
1571 metaslab_load_wait(msp);
1572
1573 /*
1574 * Move the frees from the defer_tree back to the free
1575 * range tree (if it's loaded). Swap the freed_tree and the
1576 * defer_tree -- this is safe to do because we've just emptied out
1577 * the defer_tree.
1578 */
1579 range_tree_vacate(*defer_tree,
1580 msp->ms_loaded ? range_tree_add : NULL, msp->ms_tree);
1581 range_tree_swap(freed_tree, defer_tree);
1582
1583 space_map_update(msp->ms_sm);
1584
1585 msp->ms_deferspace += defer_delta;
1586 ASSERT3S(msp->ms_deferspace, >=, 0);
1587 ASSERT3S(msp->ms_deferspace, <=, msp->ms_size);
1588 if (msp->ms_deferspace != 0) {
1589 /*
1590 * Keep syncing this metaslab until all deferred frees
1591 * are back in circulation.
1592 */
1593 vdev_dirty(vd, VDD_METASLAB, msp, txg + 1);
1594 }
1595
1596 if (msp->ms_loaded && msp->ms_access_txg < txg) {
1597 for (int t = 1; t < TXG_CONCURRENT_STATES; t++) {
1598 VERIFY0(range_tree_space(
1599 msp->ms_alloctree[(txg + t) & TXG_MASK]));
1600 }
1601
1602 if (!metaslab_debug_unload)
1603 metaslab_unload(msp);
1604 }
1605
1606 metaslab_group_sort(mg, msp, metaslab_weight(msp));
1607 mutex_exit(&msp->ms_lock);
1608
1609 }
1610
1611 void
1612 metaslab_sync_reassess(metaslab_group_t *mg)
1613 {
1614 int64_t failures = mg->mg_alloc_failures;
1615
1616 metaslab_group_alloc_update(mg);
1617 atomic_add_64(&mg->mg_alloc_failures, -failures);
1618
1619 /*
1620 * Preload the next potential metaslabs
1621 */
1622 metaslab_group_preload(mg);
1623 }
1624
1625 static uint64_t
1626 metaslab_distance(metaslab_t *msp, dva_t *dva)
1627 {
1628 uint64_t ms_shift = msp->ms_group->mg_vd->vdev_ms_shift;
1629 uint64_t offset = DVA_GET_OFFSET(dva) >> ms_shift;
1630 uint64_t start = msp->ms_id;
1631
1632 if (msp->ms_group->mg_vd->vdev_id != DVA_GET_VDEV(dva))
1633 return (1ULL << 63);
1634
1635 if (offset < start)
1636 return ((start - offset) << ms_shift);
1637 if (offset > start)
1638 return ((offset - start) << ms_shift);
1639 return (0);
1640 }
1641
1642 static uint64_t
1643 metaslab_group_alloc(metaslab_group_t *mg, uint64_t psize, uint64_t asize,
1644 uint64_t txg, uint64_t min_distance, dva_t *dva, int d, int flags)
1645 {
1646 spa_t *spa = mg->mg_vd->vdev_spa;
1647 metaslab_t *msp = NULL;
1648 uint64_t offset = -1ULL;
1649 avl_tree_t *t = &mg->mg_metaslab_tree;
1650 uint64_t activation_weight;
1651 uint64_t target_distance;
1652 int i;
1653
1654 activation_weight = METASLAB_WEIGHT_PRIMARY;
1655 for (i = 0; i < d; i++) {
1656 if (DVA_GET_VDEV(&dva[i]) == mg->mg_vd->vdev_id) {
1657 activation_weight = METASLAB_WEIGHT_SECONDARY;
1658 break;
1659 }
1660 }
1661
1662 for (;;) {
1663 boolean_t was_active;
1664
1665 mutex_enter(&mg->mg_lock);
1666 for (msp = avl_first(t); msp; msp = AVL_NEXT(t, msp)) {
1667 if (msp->ms_weight < asize) {
1668 spa_dbgmsg(spa, "%s: failed to meet weight "
1669 "requirement: vdev %llu, txg %llu, mg %p, "
1670 "msp %p, psize %llu, asize %llu, "
1671 "failures %llu, weight %llu",
1672 spa_name(spa), mg->mg_vd->vdev_id, txg,
1673 mg, msp, psize, asize,
1674 mg->mg_alloc_failures, msp->ms_weight);
1675 mutex_exit(&mg->mg_lock);
1676 return (-1ULL);
1677 }
1678
1679 /*
1680 * If the selected metaslab is condensing, skip it.
1681 */
1682 if (msp->ms_condensing)
1683 continue;
1684
1685 was_active = msp->ms_weight & METASLAB_ACTIVE_MASK;
1686 if (activation_weight == METASLAB_WEIGHT_PRIMARY)
1687 break;
1688
1689 target_distance = min_distance +
1690 (space_map_allocated(msp->ms_sm) != 0 ? 0 :
1691 min_distance >> 1);
1692
1693 for (i = 0; i < d; i++)
1694 if (metaslab_distance(msp, &dva[i]) <
1695 target_distance)
1696 break;
1697 if (i == d)
1698 break;
1699 }
1700 mutex_exit(&mg->mg_lock);
1701 if (msp == NULL)
1702 return (-1ULL);
1703
1704 mutex_enter(&msp->ms_lock);
1705
1706 /*
1707 * If we've already reached the allowable number of failed
1708 * allocation attempts on this metaslab group then we
1709 * consider skipping it. We skip it only if we're allowed
1710 * to "fast" gang, the physical size is larger than
1711 * a gang block, and we're attempting to allocate from
1712 * the primary metaslab.
1713 */
1714 if (mg->mg_alloc_failures > zfs_mg_alloc_failures &&
1715 CAN_FASTGANG(flags) && psize > SPA_GANGBLOCKSIZE &&
1716 activation_weight == METASLAB_WEIGHT_PRIMARY) {
1717 spa_dbgmsg(spa, "%s: skipping metaslab group: "
1718 "vdev %llu, txg %llu, mg %p, msp[%llu] %p, "
1719 "psize %llu, asize %llu, failures %llu",
1720 spa_name(spa), mg->mg_vd->vdev_id, txg, mg,
1721 msp->ms_id, msp, psize, asize,
1722 mg->mg_alloc_failures);
1723 mutex_exit(&msp->ms_lock);
1724 return (-1ULL);
1725 }
1726
1727 /*
1728 * Ensure that the metaslab we have selected is still
1729 * capable of handling our request. It's possible that
1730 * another thread may have changed the weight while we
1731 * were blocked on the metaslab lock.
1732 */
1733 if (msp->ms_weight < asize || (was_active &&
1734 !(msp->ms_weight & METASLAB_ACTIVE_MASK) &&
1735 activation_weight == METASLAB_WEIGHT_PRIMARY)) {
1736 mutex_exit(&msp->ms_lock);
1737 continue;
1738 }
1739
1740 if ((msp->ms_weight & METASLAB_WEIGHT_SECONDARY) &&
1741 activation_weight == METASLAB_WEIGHT_PRIMARY) {
1742 metaslab_passivate(msp,
1743 msp->ms_weight & ~METASLAB_ACTIVE_MASK);
1744 mutex_exit(&msp->ms_lock);
1745 continue;
1746 }
1747
1748 if (metaslab_activate(msp, activation_weight) != 0) {
1749 mutex_exit(&msp->ms_lock);
1750 continue;
1751 }
1752
1753 /*
1754 * If this metaslab is currently condensing then pick again as
1755 * we can't manipulate this metaslab until it's committed
1756 * to disk.
1757 */
1758 if (msp->ms_condensing) {
1759 mutex_exit(&msp->ms_lock);
1760 continue;
1761 }
1762
1763 if ((offset = metaslab_block_alloc(msp, asize)) != -1ULL)
1764 break;
1765
1766 atomic_inc_64(&mg->mg_alloc_failures);
1767
1768 metaslab_passivate(msp, metaslab_block_maxsize(msp));
1769 mutex_exit(&msp->ms_lock);
1770 }
1771
1772 if (range_tree_space(msp->ms_alloctree[txg & TXG_MASK]) == 0)
1773 vdev_dirty(mg->mg_vd, VDD_METASLAB, msp, txg);
1774
1775 range_tree_add(msp->ms_alloctree[txg & TXG_MASK], offset, asize);
1776 msp->ms_access_txg = txg + metaslab_unload_delay;
1777
1778 mutex_exit(&msp->ms_lock);
1779
1780 return (offset);
1781 }
1782
1783 /*
1784 * Allocate a block for the specified i/o.
1785 */
1786 static int
1787 metaslab_alloc_dva(spa_t *spa, metaslab_class_t *mc, uint64_t psize,
1788 dva_t *dva, int d, dva_t *hintdva, uint64_t txg, int flags)
1789 {
1790 metaslab_group_t *mg, *rotor;
1791 vdev_t *vd;
1792 int dshift = 3;
1793 int all_zero;
1794 int zio_lock = B_FALSE;
1795 boolean_t allocatable;
1796 uint64_t offset = -1ULL;
1797 uint64_t asize;
1798 uint64_t distance;
1799
1800 ASSERT(!DVA_IS_VALID(&dva[d]));
1801
1802 /*
1803 * For testing, make some blocks above a certain size be gang blocks.
1804 */
1805 if (psize >= metaslab_gang_bang && (ddi_get_lbolt() & 3) == 0)
1806 return (SET_ERROR(ENOSPC));
1807
1808 /*
1809 * Start at the rotor and loop through all mgs until we find something.
1810 * Note that there's no locking on mc_rotor or mc_aliquot because
1811 * nothing actually breaks if we miss a few updates -- we just won't
1812 * allocate quite as evenly. It all balances out over time.
1813 *
1814 * If we are doing ditto or log blocks, try to spread them across
1815 * consecutive vdevs. If we're forced to reuse a vdev before we've
1816 * allocated all of our ditto blocks, then try and spread them out on
1817 * that vdev as much as possible. If it turns out to not be possible,
1818 * gradually lower our standards until anything becomes acceptable.
1819 * Also, allocating on consecutive vdevs (as opposed to random vdevs)
1820 * gives us hope of containing our fault domains to something we're
1821 * able to reason about. Otherwise, any two top-level vdev failures
1822 * will guarantee the loss of data. With consecutive allocation,
1823 * only two adjacent top-level vdev failures will result in data loss.
1824 *
1825 * If we are doing gang blocks (hintdva is non-NULL), try to keep
1826 * ourselves on the same vdev as our gang block header. That
1827 * way, we can hope for locality in vdev_cache, plus it makes our
1828 * fault domains something tractable.
1829 */
1830 if (hintdva) {
1831 vd = vdev_lookup_top(spa, DVA_GET_VDEV(&hintdva[d]));
1832
1833 /*
1834 * It's possible the vdev we're using as the hint no
1835 * longer exists (i.e. removed). Consult the rotor when
1836 * all else fails.
1837 */
1838 if (vd != NULL) {
1839 mg = vd->vdev_mg;
1840
1841 if (flags & METASLAB_HINTBP_AVOID &&
1842 mg->mg_next != NULL)
1843 mg = mg->mg_next;
1844 } else {
1845 mg = mc->mc_rotor;
1846 }
1847 } else if (d != 0) {
1848 vd = vdev_lookup_top(spa, DVA_GET_VDEV(&dva[d - 1]));
1849 mg = vd->vdev_mg->mg_next;
1850 } else {
1851 mg = mc->mc_rotor;
1852 }
1853
1854 /*
1855 * If the hint put us into the wrong metaslab class, or into a
1856 * metaslab group that has been passivated, just follow the rotor.
1857 */
1858 if (mg->mg_class != mc || mg->mg_activation_count <= 0)
1859 mg = mc->mc_rotor;
1860
1861 rotor = mg;
1862 top:
1863 all_zero = B_TRUE;
1864 do {
1865 ASSERT(mg->mg_activation_count == 1);
1866
1867 vd = mg->mg_vd;
1868
1869 /*
1870 * Don't allocate from faulted devices.
1871 */
1872 if (zio_lock) {
1873 spa_config_enter(spa, SCL_ZIO, FTAG, RW_READER);
1874 allocatable = vdev_allocatable(vd);
1875 spa_config_exit(spa, SCL_ZIO, FTAG);
1876 } else {
1877 allocatable = vdev_allocatable(vd);
1878 }
1879
1880 /*
1881 * Determine if the selected metaslab group is eligible
1882 * for allocations. If we're ganging or have requested
1883 * an allocation for the smallest gang block size
1884 * then we don't want to avoid allocating to the this
1885 * metaslab group. If we're in this condition we should
1886 * try to allocate from any device possible so that we
1887 * don't inadvertently return ENOSPC and suspend the pool
1888 * even though space is still available.
1889 */
1890 if (allocatable && CAN_FASTGANG(flags) &&
1891 psize > SPA_GANGBLOCKSIZE)
1892 allocatable = metaslab_group_allocatable(mg);
1893
1894 if (!allocatable)
1895 goto next;
1896
1897 /*
1898 * Avoid writing single-copy data to a failing vdev
1899 * unless the user instructs us that it is okay.
1900 */
1901 if ((vd->vdev_stat.vs_write_errors > 0 ||
1902 vd->vdev_state < VDEV_STATE_HEALTHY) &&
1903 d == 0 && dshift == 3 &&
1904 !(zfs_write_to_degraded && vd->vdev_state ==
1905 VDEV_STATE_DEGRADED)) {
1906 all_zero = B_FALSE;
1907 goto next;
1908 }
1909
1910 ASSERT(mg->mg_class == mc);
1911
1912 distance = vd->vdev_asize >> dshift;
1913 if (distance <= (1ULL << vd->vdev_ms_shift))
1914 distance = 0;
1915 else
1916 all_zero = B_FALSE;
1917
1918 asize = vdev_psize_to_asize(vd, psize);
1919 ASSERT(P2PHASE(asize, 1ULL << vd->vdev_ashift) == 0);
1920
1921 offset = metaslab_group_alloc(mg, psize, asize, txg, distance,
1922 dva, d, flags);
1923 if (offset != -1ULL) {
1924 /*
1925 * If we've just selected this metaslab group,
1926 * figure out whether the corresponding vdev is
1927 * over- or under-used relative to the pool,
1928 * and set an allocation bias to even it out.
1929 */
1930 if (mc->mc_aliquot == 0) {
1931 vdev_stat_t *vs = &vd->vdev_stat;
1932 int64_t vu, cu;
1933
1934 vu = (vs->vs_alloc * 100) / (vs->vs_space + 1);
1935 cu = (mc->mc_alloc * 100) / (mc->mc_space + 1);
1936
1937 /*
1938 * Calculate how much more or less we should
1939 * try to allocate from this device during
1940 * this iteration around the rotor.
1941 * For example, if a device is 80% full
1942 * and the pool is 20% full then we should
1943 * reduce allocations by 60% on this device.
1944 *
1945 * mg_bias = (20 - 80) * 512K / 100 = -307K
1946 *
1947 * This reduces allocations by 307K for this
1948 * iteration.
1949 */
1950 mg->mg_bias = ((cu - vu) *
1951 (int64_t)mg->mg_aliquot) / 100;
1952 }
1953
1954 if (atomic_add_64_nv(&mc->mc_aliquot, asize) >=
1955 mg->mg_aliquot + mg->mg_bias) {
1956 mc->mc_rotor = mg->mg_next;
1957 mc->mc_aliquot = 0;
1958 }
1959
1960 DVA_SET_VDEV(&dva[d], vd->vdev_id);
1961 DVA_SET_OFFSET(&dva[d], offset);
1962 DVA_SET_GANG(&dva[d], !!(flags & METASLAB_GANG_HEADER));
1963 DVA_SET_ASIZE(&dva[d], asize);
1964
1965 return (0);
1966 }
1967 next:
1968 mc->mc_rotor = mg->mg_next;
1969 mc->mc_aliquot = 0;
1970 } while ((mg = mg->mg_next) != rotor);
1971
1972 if (!all_zero) {
1973 dshift++;
1974 ASSERT(dshift < 64);
1975 goto top;
1976 }
1977
1978 if (!allocatable && !zio_lock) {
1979 dshift = 3;
1980 zio_lock = B_TRUE;
1981 goto top;
1982 }
1983
1984 bzero(&dva[d], sizeof (dva_t));
1985
1986 return (SET_ERROR(ENOSPC));
1987 }
1988
1989 /*
1990 * Free the block represented by DVA in the context of the specified
1991 * transaction group.
1992 */
1993 static void
1994 metaslab_free_dva(spa_t *spa, const dva_t *dva, uint64_t txg, boolean_t now)
1995 {
1996 uint64_t vdev = DVA_GET_VDEV(dva);
1997 uint64_t offset = DVA_GET_OFFSET(dva);
1998 uint64_t size = DVA_GET_ASIZE(dva);
1999 vdev_t *vd;
2000 metaslab_t *msp;
2001
2002 ASSERT(DVA_IS_VALID(dva));
2003
2004 if (txg > spa_freeze_txg(spa))
2005 return;
2006
2007 if ((vd = vdev_lookup_top(spa, vdev)) == NULL ||
2008 (offset >> vd->vdev_ms_shift) >= vd->vdev_ms_count) {
2009 cmn_err(CE_WARN, "metaslab_free_dva(): bad DVA %llu:%llu",
2010 (u_longlong_t)vdev, (u_longlong_t)offset);
2011 ASSERT(0);
2012 return;
2013 }
2014
2015 msp = vd->vdev_ms[offset >> vd->vdev_ms_shift];
2016
2017 if (DVA_GET_GANG(dva))
2018 size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
2019
2020 mutex_enter(&msp->ms_lock);
2021
2022 if (now) {
2023 range_tree_remove(msp->ms_alloctree[txg & TXG_MASK],
2024 offset, size);
2025
2026 VERIFY(!msp->ms_condensing);
2027 VERIFY3U(offset, >=, msp->ms_start);
2028 VERIFY3U(offset + size, <=, msp->ms_start + msp->ms_size);
2029 VERIFY3U(range_tree_space(msp->ms_tree) + size, <=,
2030 msp->ms_size);
2031 VERIFY0(P2PHASE(offset, 1ULL << vd->vdev_ashift));
2032 VERIFY0(P2PHASE(size, 1ULL << vd->vdev_ashift));
2033 range_tree_add(msp->ms_tree, offset, size);
2034 } else {
2035 if (range_tree_space(msp->ms_freetree[txg & TXG_MASK]) == 0)
2036 vdev_dirty(vd, VDD_METASLAB, msp, txg);
2037 range_tree_add(msp->ms_freetree[txg & TXG_MASK],
2038 offset, size);
2039 }
2040
2041 mutex_exit(&msp->ms_lock);
2042 }
2043
2044 /*
2045 * Intent log support: upon opening the pool after a crash, notify the SPA
2046 * of blocks that the intent log has allocated for immediate write, but
2047 * which are still considered free by the SPA because the last transaction
2048 * group didn't commit yet.
2049 */
2050 static int
2051 metaslab_claim_dva(spa_t *spa, const dva_t *dva, uint64_t txg)
2052 {
2053 uint64_t vdev = DVA_GET_VDEV(dva);
2054 uint64_t offset = DVA_GET_OFFSET(dva);
2055 uint64_t size = DVA_GET_ASIZE(dva);
2056 vdev_t *vd;
2057 metaslab_t *msp;
2058 int error = 0;
2059
2060 ASSERT(DVA_IS_VALID(dva));
2061
2062 if ((vd = vdev_lookup_top(spa, vdev)) == NULL ||
2063 (offset >> vd->vdev_ms_shift) >= vd->vdev_ms_count)
2064 return (SET_ERROR(ENXIO));
2065
2066 msp = vd->vdev_ms[offset >> vd->vdev_ms_shift];
2067
2068 if (DVA_GET_GANG(dva))
2069 size = vdev_psize_to_asize(vd, SPA_GANGBLOCKSIZE);
2070
2071 mutex_enter(&msp->ms_lock);
2072
2073 if ((txg != 0 && spa_writeable(spa)) || !msp->ms_loaded)
2074 error = metaslab_activate(msp, METASLAB_WEIGHT_SECONDARY);
2075
2076 if (error == 0 && !range_tree_contains(msp->ms_tree, offset, size))
2077 error = SET_ERROR(ENOENT);
2078
2079 if (error || txg == 0) { /* txg == 0 indicates dry run */
2080 mutex_exit(&msp->ms_lock);
2081 return (error);
2082 }
2083
2084 VERIFY(!msp->ms_condensing);
2085 VERIFY0(P2PHASE(offset, 1ULL << vd->vdev_ashift));
2086 VERIFY0(P2PHASE(size, 1ULL << vd->vdev_ashift));
2087 VERIFY3U(range_tree_space(msp->ms_tree) - size, <=, msp->ms_size);
2088 range_tree_remove(msp->ms_tree, offset, size);
2089
2090 if (spa_writeable(spa)) { /* don't dirty if we're zdb(1M) */
2091 if (range_tree_space(msp->ms_alloctree[txg & TXG_MASK]) == 0)
2092 vdev_dirty(vd, VDD_METASLAB, msp, txg);
2093 range_tree_add(msp->ms_alloctree[txg & TXG_MASK], offset, size);
2094 }
2095
2096 mutex_exit(&msp->ms_lock);
2097
2098 return (0);
2099 }
2100
2101 int
2102 metaslab_alloc(spa_t *spa, metaslab_class_t *mc, uint64_t psize, blkptr_t *bp,
2103 int ndvas, uint64_t txg, blkptr_t *hintbp, int flags)
2104 {
2105 dva_t *dva = bp->blk_dva;
2106 dva_t *hintdva = hintbp->blk_dva;
2107 int error = 0;
2108
2109 ASSERT(bp->blk_birth == 0);
2110 ASSERT(BP_PHYSICAL_BIRTH(bp) == 0);
2111
2112 spa_config_enter(spa, SCL_ALLOC, FTAG, RW_READER);
2113
2114 if (mc->mc_rotor == NULL) { /* no vdevs in this class */
2115 spa_config_exit(spa, SCL_ALLOC, FTAG);
2116 return (SET_ERROR(ENOSPC));
2117 }
2118
2119 ASSERT(ndvas > 0 && ndvas <= spa_max_replication(spa));
2120 ASSERT(BP_GET_NDVAS(bp) == 0);
2121 ASSERT(hintbp == NULL || ndvas <= BP_GET_NDVAS(hintbp));
2122
2123 for (int d = 0; d < ndvas; d++) {
2124 error = metaslab_alloc_dva(spa, mc, psize, dva, d, hintdva,
2125 txg, flags);
2126 if (error != 0) {
2127 for (d--; d >= 0; d--) {
2128 metaslab_free_dva(spa, &dva[d], txg, B_TRUE);
2129 bzero(&dva[d], sizeof (dva_t));
2130 }
2131 spa_config_exit(spa, SCL_ALLOC, FTAG);
2132 return (error);
2133 }
2134 }
2135 ASSERT(error == 0);
2136 ASSERT(BP_GET_NDVAS(bp) == ndvas);
2137
2138 spa_config_exit(spa, SCL_ALLOC, FTAG);
2139
2140 BP_SET_BIRTH(bp, txg, txg);
2141
2142 return (0);
2143 }
2144
2145 void
2146 metaslab_free(spa_t *spa, const blkptr_t *bp, uint64_t txg, boolean_t now)
2147 {
2148 const dva_t *dva = bp->blk_dva;
2149 int ndvas = BP_GET_NDVAS(bp);
2150
2151 ASSERT(!BP_IS_HOLE(bp));
2152 ASSERT(!now || bp->blk_birth >= spa_syncing_txg(spa));
2153
2154 spa_config_enter(spa, SCL_FREE, FTAG, RW_READER);
2155
2156 for (int d = 0; d < ndvas; d++)
2157 metaslab_free_dva(spa, &dva[d], txg, now);
2158
2159 spa_config_exit(spa, SCL_FREE, FTAG);
2160 }
2161
2162 int
2163 metaslab_claim(spa_t *spa, const blkptr_t *bp, uint64_t txg)
2164 {
2165 const dva_t *dva = bp->blk_dva;
2166 int ndvas = BP_GET_NDVAS(bp);
2167 int error = 0;
2168
2169 ASSERT(!BP_IS_HOLE(bp));
2170
2171 if (txg != 0) {
2172 /*
2173 * First do a dry run to make sure all DVAs are claimable,
2174 * so we don't have to unwind from partial failures below.
2175 */
2176 if ((error = metaslab_claim(spa, bp, 0)) != 0)
2177 return (error);
2178 }
2179
2180 spa_config_enter(spa, SCL_ALLOC, FTAG, RW_READER);
2181
2182 for (int d = 0; d < ndvas; d++)
2183 if ((error = metaslab_claim_dva(spa, &dva[d], txg)) != 0)
2184 break;
2185
2186 spa_config_exit(spa, SCL_ALLOC, FTAG);
2187
2188 ASSERT(error == 0 || txg == 0);
2189
2190 return (error);
2191 }
2192
2193 void
2194 metaslab_check_free(spa_t *spa, const blkptr_t *bp)
2195 {
2196 if ((zfs_flags & ZFS_DEBUG_ZIO_FREE) == 0)
2197 return;
2198
2199 spa_config_enter(spa, SCL_VDEV, FTAG, RW_READER);
2200 for (int i = 0; i < BP_GET_NDVAS(bp); i++) {
2201 uint64_t vdev = DVA_GET_VDEV(&bp->blk_dva[i]);
2202 vdev_t *vd = vdev_lookup_top(spa, vdev);
2203 uint64_t offset = DVA_GET_OFFSET(&bp->blk_dva[i]);
2204 uint64_t size = DVA_GET_ASIZE(&bp->blk_dva[i]);
2205 metaslab_t *msp = vd->vdev_ms[offset >> vd->vdev_ms_shift];
2206
2207 if (msp->ms_loaded)
2208 range_tree_verify(msp->ms_tree, offset, size);
2209
2210 for (int j = 0; j < TXG_SIZE; j++)
2211 range_tree_verify(msp->ms_freetree[j], offset, size);
2212 for (int j = 0; j < TXG_DEFER_SIZE; j++)
2213 range_tree_verify(msp->ms_defertree[j], offset, size);
2214 }
2215 spa_config_exit(spa, SCL_VDEV, FTAG);
2216 }