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 /*
23 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
24 * Copyright (c) 2011, 2018 by Delphix. All rights reserved.
25 */
26
27 #include <sys/zfs_context.h>
28 #include <sys/spa_impl.h>
29 #include <sys/dmu.h>
30 #include <sys/dmu_tx.h>
31 #include <sys/zap.h>
32 #include <sys/vdev_impl.h>
33 #include <sys/metaslab.h>
34 #include <sys/metaslab_impl.h>
35 #include <sys/uberblock_impl.h>
36 #include <sys/txg.h>
37 #include <sys/avl.h>
38 #include <sys/bpobj.h>
39 #include <sys/dsl_pool.h>
40 #include <sys/dsl_synctask.h>
41 #include <sys/dsl_dir.h>
42 #include <sys/arc.h>
43 #include <sys/zfeature.h>
44 #include <sys/vdev_indirect_births.h>
45 #include <sys/vdev_indirect_mapping.h>
46 #include <sys/abd.h>
47 #include <sys/vdev_initialize.h>
48
49 /*
50 * This file contains the necessary logic to remove vdevs from a
51 * storage pool. Currently, the only devices that can be removed
52 * are log, cache, and spare devices; and top level vdevs from a pool
53 * w/o raidz. (Note that members of a mirror can also be removed
54 * by the detach operation.)
55 *
56 * Log vdevs are removed by evacuating them and then turning the vdev
57 * into a hole vdev while holding spa config locks.
58 *
59 * Top level vdevs are removed and converted into an indirect vdev via
60 * a multi-step process:
61 *
62 * - Disable allocations from this device (spa_vdev_remove_top).
63 *
64 * - From a new thread (spa_vdev_remove_thread), copy data from
65 * the removing vdev to a different vdev. The copy happens in open
66 * context (spa_vdev_copy_impl) and issues a sync task
67 * (vdev_mapping_sync) so the sync thread can update the partial
68 * indirect mappings in core and on disk.
69 *
70 * - If a free happens during a removal, it is freed from the
71 * removing vdev, and if it has already been copied, from the new
72 * location as well (free_from_removing_vdev).
73 *
74 * - After the removal is completed, the copy thread converts the vdev
75 * into an indirect vdev (vdev_remove_complete) before instructing
76 * the sync thread to destroy the space maps and finish the removal
77 * (spa_finish_removal).
78 */
79
80 typedef struct vdev_copy_arg {
81 metaslab_t *vca_msp;
82 uint64_t vca_outstanding_bytes;
83 kcondvar_t vca_cv;
84 kmutex_t vca_lock;
85 } vdev_copy_arg_t;
86
87 /*
88 * The maximum amount of memory we can use for outstanding i/o while
89 * doing a device removal. This determines how much i/o we can have
90 * in flight concurrently.
91 */
92 int zfs_remove_max_copy_bytes = 64 * 1024 * 1024;
93
94 /*
95 * The largest contiguous segment that we will attempt to allocate when
96 * removing a device. This can be no larger than SPA_MAXBLOCKSIZE. If
97 * there is a performance problem with attempting to allocate large blocks,
98 * consider decreasing this.
99 *
100 * Note: we will issue I/Os of up to this size. The mpt driver does not
101 * respond well to I/Os larger than 1MB, so we set this to 1MB. (When
102 * mpt processes an I/O larger than 1MB, it needs to do an allocation of
103 * 2 physically contiguous pages; if this allocation fails, mpt will drop
104 * the I/O and hang the device.)
105 */
106 int zfs_remove_max_segment = 1024 * 1024;
107
108 /*
109 * Allow a remap segment to span free chunks of at most this size. The main
110 * impact of a larger span is that we will read and write larger, more
111 * contiguous chunks, with more "unnecessary" data -- trading off bandwidth
112 * for iops. The value here was chosen to align with
113 * zfs_vdev_read_gap_limit, which is a similar concept when doing regular
114 * reads (but there's no reason it has to be the same).
115 *
116 * Additionally, a higher span will have the following relatively minor
117 * effects:
118 * - the mapping will be smaller, since one entry can cover more allocated
119 * segments
120 * - more of the fragmentation in the removing device will be preserved
121 * - we'll do larger allocations, which may fail and fall back on smaller
122 * allocations
123 */
124 int vdev_removal_max_span = 32 * 1024;
125
126 /*
127 * This is used by the test suite so that it can ensure that certain
128 * actions happen while in the middle of a removal.
129 */
130 uint64_t zfs_remove_max_bytes_pause = UINT64_MAX;
131
132 #define VDEV_REMOVAL_ZAP_OBJS "lzap"
133
134 static void spa_vdev_remove_thread(void *arg);
135
136 static void
137 spa_sync_removing_state(spa_t *spa, dmu_tx_t *tx)
138 {
139 VERIFY0(zap_update(spa->spa_dsl_pool->dp_meta_objset,
140 DMU_POOL_DIRECTORY_OBJECT,
141 DMU_POOL_REMOVING, sizeof (uint64_t),
142 sizeof (spa->spa_removing_phys) / sizeof (uint64_t),
143 &spa->spa_removing_phys, tx));
144 }
145
146 static nvlist_t *
147 spa_nvlist_lookup_by_guid(nvlist_t **nvpp, int count, uint64_t target_guid)
148 {
149 for (int i = 0; i < count; i++) {
150 uint64_t guid =
151 fnvlist_lookup_uint64(nvpp[i], ZPOOL_CONFIG_GUID);
152
153 if (guid == target_guid)
154 return (nvpp[i]);
155 }
156
157 return (NULL);
158 }
159
160 static void
161 spa_vdev_remove_aux(nvlist_t *config, char *name, nvlist_t **dev, int count,
162 nvlist_t *dev_to_remove)
163 {
164 nvlist_t **newdev = NULL;
165
166 if (count > 1)
167 newdev = kmem_alloc((count - 1) * sizeof (void *), KM_SLEEP);
168
169 for (int i = 0, j = 0; i < count; i++) {
170 if (dev[i] == dev_to_remove)
171 continue;
172 VERIFY(nvlist_dup(dev[i], &newdev[j++], KM_SLEEP) == 0);
173 }
174
175 VERIFY(nvlist_remove(config, name, DATA_TYPE_NVLIST_ARRAY) == 0);
176 VERIFY(nvlist_add_nvlist_array(config, name, newdev, count - 1) == 0);
177
178 for (int i = 0; i < count - 1; i++)
179 nvlist_free(newdev[i]);
180
181 if (count > 1)
182 kmem_free(newdev, (count - 1) * sizeof (void *));
183 }
184
185 static spa_vdev_removal_t *
186 spa_vdev_removal_create(vdev_t *vd)
187 {
188 spa_vdev_removal_t *svr = kmem_zalloc(sizeof (*svr), KM_SLEEP);
189 mutex_init(&svr->svr_lock, NULL, MUTEX_DEFAULT, NULL);
190 cv_init(&svr->svr_cv, NULL, CV_DEFAULT, NULL);
191 svr->svr_allocd_segs = range_tree_create(NULL, NULL);
192 svr->svr_vdev_id = vd->vdev_id;
193
194 for (int i = 0; i < TXG_SIZE; i++) {
195 svr->svr_frees[i] = range_tree_create(NULL, NULL);
196 list_create(&svr->svr_new_segments[i],
197 sizeof (vdev_indirect_mapping_entry_t),
198 offsetof(vdev_indirect_mapping_entry_t, vime_node));
199 }
200
201 return (svr);
202 }
203
204 void
205 spa_vdev_removal_destroy(spa_vdev_removal_t *svr)
206 {
207 for (int i = 0; i < TXG_SIZE; i++) {
208 ASSERT0(svr->svr_bytes_done[i]);
209 ASSERT0(svr->svr_max_offset_to_sync[i]);
210 range_tree_destroy(svr->svr_frees[i]);
211 list_destroy(&svr->svr_new_segments[i]);
212 }
213
214 range_tree_destroy(svr->svr_allocd_segs);
215 mutex_destroy(&svr->svr_lock);
216 cv_destroy(&svr->svr_cv);
217 kmem_free(svr, sizeof (*svr));
218 }
219
220 /*
221 * This is called as a synctask in the txg in which we will mark this vdev
222 * as removing (in the config stored in the MOS).
223 *
224 * It begins the evacuation of a toplevel vdev by:
225 * - initializing the spa_removing_phys which tracks this removal
226 * - computing the amount of space to remove for accounting purposes
227 * - dirtying all dbufs in the spa_config_object
228 * - creating the spa_vdev_removal
229 * - starting the spa_vdev_remove_thread
230 */
231 static void
232 vdev_remove_initiate_sync(void *arg, dmu_tx_t *tx)
233 {
234 int vdev_id = (uintptr_t)arg;
235 spa_t *spa = dmu_tx_pool(tx)->dp_spa;
236 vdev_t *vd = vdev_lookup_top(spa, vdev_id);
237 vdev_indirect_config_t *vic = &vd->vdev_indirect_config;
238 objset_t *mos = spa->spa_dsl_pool->dp_meta_objset;
239 spa_vdev_removal_t *svr = NULL;
240 uint64_t txg = dmu_tx_get_txg(tx);
241
242 ASSERT3P(vd->vdev_ops, !=, &vdev_raidz_ops);
243 svr = spa_vdev_removal_create(vd);
244
245 ASSERT(vd->vdev_removing);
246 ASSERT3P(vd->vdev_indirect_mapping, ==, NULL);
247
248 spa_feature_incr(spa, SPA_FEATURE_DEVICE_REMOVAL, tx);
249 if (spa_feature_is_enabled(spa, SPA_FEATURE_OBSOLETE_COUNTS)) {
250 /*
251 * By activating the OBSOLETE_COUNTS feature, we prevent
252 * the pool from being downgraded and ensure that the
253 * refcounts are precise.
254 */
255 spa_feature_incr(spa, SPA_FEATURE_OBSOLETE_COUNTS, tx);
256 uint64_t one = 1;
257 VERIFY0(zap_add(spa->spa_meta_objset, vd->vdev_top_zap,
258 VDEV_TOP_ZAP_OBSOLETE_COUNTS_ARE_PRECISE, sizeof (one), 1,
259 &one, tx));
260 ASSERT3U(vdev_obsolete_counts_are_precise(vd), !=, 0);
261 }
262
263 vic->vic_mapping_object = vdev_indirect_mapping_alloc(mos, tx);
264 vd->vdev_indirect_mapping =
265 vdev_indirect_mapping_open(mos, vic->vic_mapping_object);
266 vic->vic_births_object = vdev_indirect_births_alloc(mos, tx);
267 vd->vdev_indirect_births =
268 vdev_indirect_births_open(mos, vic->vic_births_object);
269 spa->spa_removing_phys.sr_removing_vdev = vd->vdev_id;
270 spa->spa_removing_phys.sr_start_time = gethrestime_sec();
271 spa->spa_removing_phys.sr_end_time = 0;
272 spa->spa_removing_phys.sr_state = DSS_SCANNING;
273 spa->spa_removing_phys.sr_to_copy = 0;
274 spa->spa_removing_phys.sr_copied = 0;
275
276 /*
277 * Note: We can't use vdev_stat's vs_alloc for sr_to_copy, because
278 * there may be space in the defer tree, which is free, but still
279 * counted in vs_alloc.
280 */
281 for (uint64_t i = 0; i < vd->vdev_ms_count; i++) {
282 metaslab_t *ms = vd->vdev_ms[i];
283 if (ms->ms_sm == NULL)
284 continue;
285
286 spa->spa_removing_phys.sr_to_copy +=
287 metaslab_allocated_space(ms);
288
289 /*
290 * Space which we are freeing this txg does not need to
291 * be copied.
292 */
293 spa->spa_removing_phys.sr_to_copy -=
294 range_tree_space(ms->ms_freeing);
295
296 ASSERT0(range_tree_space(ms->ms_freed));
297 for (int t = 0; t < TXG_SIZE; t++)
298 ASSERT0(range_tree_space(ms->ms_allocating[t]));
299 }
300
301 /*
302 * Sync tasks are called before metaslab_sync(), so there should
303 * be no already-synced metaslabs in the TXG_CLEAN list.
304 */
305 ASSERT3P(txg_list_head(&vd->vdev_ms_list, TXG_CLEAN(txg)), ==, NULL);
306
307 spa_sync_removing_state(spa, tx);
308
309 /*
310 * All blocks that we need to read the most recent mapping must be
311 * stored on concrete vdevs. Therefore, we must dirty anything that
312 * is read before spa_remove_init(). Specifically, the
313 * spa_config_object. (Note that although we already modified the
314 * spa_config_object in spa_sync_removing_state, that may not have
315 * modified all blocks of the object.)
316 */
317 dmu_object_info_t doi;
318 VERIFY0(dmu_object_info(mos, DMU_POOL_DIRECTORY_OBJECT, &doi));
319 for (uint64_t offset = 0; offset < doi.doi_max_offset; ) {
320 dmu_buf_t *dbuf;
321 VERIFY0(dmu_buf_hold(mos, DMU_POOL_DIRECTORY_OBJECT,
322 offset, FTAG, &dbuf, 0));
323 dmu_buf_will_dirty(dbuf, tx);
324 offset += dbuf->db_size;
325 dmu_buf_rele(dbuf, FTAG);
326 }
327
328 /*
329 * Now that we've allocated the im_object, dirty the vdev to ensure
330 * that the object gets written to the config on disk.
331 */
332 vdev_config_dirty(vd);
333
334 zfs_dbgmsg("starting removal thread for vdev %llu (%p) in txg %llu "
335 "im_obj=%llu", vd->vdev_id, vd, dmu_tx_get_txg(tx),
336 vic->vic_mapping_object);
337
338 spa_history_log_internal(spa, "vdev remove started", tx,
339 "%s vdev %llu %s", spa_name(spa), vd->vdev_id,
340 (vd->vdev_path != NULL) ? vd->vdev_path : "-");
341 /*
342 * Setting spa_vdev_removal causes subsequent frees to call
343 * free_from_removing_vdev(). Note that we don't need any locking
344 * because we are the sync thread, and metaslab_free_impl() is only
345 * called from syncing context (potentially from a zio taskq thread,
346 * but in any case only when there are outstanding free i/os, which
347 * there are not).
348 */
349 ASSERT3P(spa->spa_vdev_removal, ==, NULL);
350 spa->spa_vdev_removal = svr;
351 svr->svr_thread = thread_create(NULL, 0,
352 spa_vdev_remove_thread, spa, 0, &p0, TS_RUN, minclsyspri);
353 }
354
355 /*
356 * When we are opening a pool, we must read the mapping for each
357 * indirect vdev in order from most recently removed to least
358 * recently removed. We do this because the blocks for the mapping
359 * of older indirect vdevs may be stored on more recently removed vdevs.
360 * In order to read each indirect mapping object, we must have
361 * initialized all more recently removed vdevs.
362 */
363 int
364 spa_remove_init(spa_t *spa)
365 {
366 int error;
367
368 error = zap_lookup(spa->spa_dsl_pool->dp_meta_objset,
369 DMU_POOL_DIRECTORY_OBJECT,
370 DMU_POOL_REMOVING, sizeof (uint64_t),
371 sizeof (spa->spa_removing_phys) / sizeof (uint64_t),
372 &spa->spa_removing_phys);
373
374 if (error == ENOENT) {
375 spa->spa_removing_phys.sr_state = DSS_NONE;
376 spa->spa_removing_phys.sr_removing_vdev = -1;
377 spa->spa_removing_phys.sr_prev_indirect_vdev = -1;
378 spa->spa_indirect_vdevs_loaded = B_TRUE;
379 return (0);
380 } else if (error != 0) {
381 return (error);
382 }
383
384 if (spa->spa_removing_phys.sr_state == DSS_SCANNING) {
385 /*
386 * We are currently removing a vdev. Create and
387 * initialize a spa_vdev_removal_t from the bonus
388 * buffer of the removing vdevs vdev_im_object, and
389 * initialize its partial mapping.
390 */
391 spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
392 vdev_t *vd = vdev_lookup_top(spa,
393 spa->spa_removing_phys.sr_removing_vdev);
394
395 if (vd == NULL) {
396 spa_config_exit(spa, SCL_STATE, FTAG);
397 return (EINVAL);
398 }
399
400 vdev_indirect_config_t *vic = &vd->vdev_indirect_config;
401
402 ASSERT(vdev_is_concrete(vd));
403 spa_vdev_removal_t *svr = spa_vdev_removal_create(vd);
404 ASSERT3U(svr->svr_vdev_id, ==, vd->vdev_id);
405 ASSERT(vd->vdev_removing);
406
407 vd->vdev_indirect_mapping = vdev_indirect_mapping_open(
408 spa->spa_meta_objset, vic->vic_mapping_object);
409 vd->vdev_indirect_births = vdev_indirect_births_open(
410 spa->spa_meta_objset, vic->vic_births_object);
411 spa_config_exit(spa, SCL_STATE, FTAG);
412
413 spa->spa_vdev_removal = svr;
414 }
415
416 spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
417 uint64_t indirect_vdev_id =
418 spa->spa_removing_phys.sr_prev_indirect_vdev;
419 while (indirect_vdev_id != UINT64_MAX) {
420 vdev_t *vd = vdev_lookup_top(spa, indirect_vdev_id);
421 vdev_indirect_config_t *vic = &vd->vdev_indirect_config;
422
423 ASSERT3P(vd->vdev_ops, ==, &vdev_indirect_ops);
424 vd->vdev_indirect_mapping = vdev_indirect_mapping_open(
425 spa->spa_meta_objset, vic->vic_mapping_object);
426 vd->vdev_indirect_births = vdev_indirect_births_open(
427 spa->spa_meta_objset, vic->vic_births_object);
428
429 indirect_vdev_id = vic->vic_prev_indirect_vdev;
430 }
431 spa_config_exit(spa, SCL_STATE, FTAG);
432
433 /*
434 * Now that we've loaded all the indirect mappings, we can allow
435 * reads from other blocks (e.g. via predictive prefetch).
436 */
437 spa->spa_indirect_vdevs_loaded = B_TRUE;
438 return (0);
439 }
440
441 void
442 spa_restart_removal(spa_t *spa)
443 {
444 spa_vdev_removal_t *svr = spa->spa_vdev_removal;
445
446 if (svr == NULL)
447 return;
448
449 /*
450 * In general when this function is called there is no
451 * removal thread running. The only scenario where this
452 * is not true is during spa_import() where this function
453 * is called twice [once from spa_import_impl() and
454 * spa_async_resume()]. Thus, in the scenario where we
455 * import a pool that has an ongoing removal we don't
456 * want to spawn a second thread.
457 */
458 if (svr->svr_thread != NULL)
459 return;
460
461 if (!spa_writeable(spa))
462 return;
463
464 zfs_dbgmsg("restarting removal of %llu", svr->svr_vdev_id);
465 svr->svr_thread = thread_create(NULL, 0, spa_vdev_remove_thread, spa,
466 0, &p0, TS_RUN, minclsyspri);
467 }
468
469 /*
470 * Process freeing from a device which is in the middle of being removed.
471 * We must handle this carefully so that we attempt to copy freed data,
472 * and we correctly free already-copied data.
473 */
474 void
475 free_from_removing_vdev(vdev_t *vd, uint64_t offset, uint64_t size)
476 {
477 spa_t *spa = vd->vdev_spa;
478 spa_vdev_removal_t *svr = spa->spa_vdev_removal;
479 vdev_indirect_mapping_t *vim = vd->vdev_indirect_mapping;
480 uint64_t txg = spa_syncing_txg(spa);
481 uint64_t max_offset_yet = 0;
482
483 ASSERT(vd->vdev_indirect_config.vic_mapping_object != 0);
484 ASSERT3U(vd->vdev_indirect_config.vic_mapping_object, ==,
485 vdev_indirect_mapping_object(vim));
486 ASSERT3U(vd->vdev_id, ==, svr->svr_vdev_id);
487
488 mutex_enter(&svr->svr_lock);
489
490 /*
491 * Remove the segment from the removing vdev's spacemap. This
492 * ensures that we will not attempt to copy this space (if the
493 * removal thread has not yet visited it), and also ensures
494 * that we know what is actually allocated on the new vdevs
495 * (needed if we cancel the removal).
496 *
497 * Note: we must do the metaslab_free_concrete() with the svr_lock
498 * held, so that the remove_thread can not load this metaslab and then
499 * visit this offset between the time that we metaslab_free_concrete()
500 * and when we check to see if it has been visited.
501 *
502 * Note: The checkpoint flag is set to false as having/taking
503 * a checkpoint and removing a device can't happen at the same
504 * time.
505 */
506 ASSERT(!spa_has_checkpoint(spa));
507 metaslab_free_concrete(vd, offset, size, B_FALSE);
508
509 uint64_t synced_size = 0;
510 uint64_t synced_offset = 0;
511 uint64_t max_offset_synced = vdev_indirect_mapping_max_offset(vim);
512 if (offset < max_offset_synced) {
513 /*
514 * The mapping for this offset is already on disk.
515 * Free from the new location.
516 *
517 * Note that we use svr_max_synced_offset because it is
518 * updated atomically with respect to the in-core mapping.
519 * By contrast, vim_max_offset is not.
520 *
521 * This block may be split between a synced entry and an
522 * in-flight or unvisited entry. Only process the synced
523 * portion of it here.
524 */
525 synced_size = MIN(size, max_offset_synced - offset);
526 synced_offset = offset;
527
528 ASSERT3U(max_offset_yet, <=, max_offset_synced);
529 max_offset_yet = max_offset_synced;
530
531 DTRACE_PROBE3(remove__free__synced,
532 spa_t *, spa,
533 uint64_t, offset,
534 uint64_t, synced_size);
535
536 size -= synced_size;
537 offset += synced_size;
538 }
539
540 /*
541 * Look at all in-flight txgs starting from the currently syncing one
542 * and see if a section of this free is being copied. By starting from
543 * this txg and iterating forward, we might find that this region
544 * was copied in two different txgs and handle it appropriately.
545 */
546 for (int i = 0; i < TXG_CONCURRENT_STATES; i++) {
547 int txgoff = (txg + i) & TXG_MASK;
548 if (size > 0 && offset < svr->svr_max_offset_to_sync[txgoff]) {
549 /*
550 * The mapping for this offset is in flight, and
551 * will be synced in txg+i.
552 */
553 uint64_t inflight_size = MIN(size,
554 svr->svr_max_offset_to_sync[txgoff] - offset);
555
556 DTRACE_PROBE4(remove__free__inflight,
557 spa_t *, spa,
558 uint64_t, offset,
559 uint64_t, inflight_size,
560 uint64_t, txg + i);
561
562 /*
563 * We copy data in order of increasing offset.
564 * Therefore the max_offset_to_sync[] must increase
565 * (or be zero, indicating that nothing is being
566 * copied in that txg).
567 */
568 if (svr->svr_max_offset_to_sync[txgoff] != 0) {
569 ASSERT3U(svr->svr_max_offset_to_sync[txgoff],
570 >=, max_offset_yet);
571 max_offset_yet =
572 svr->svr_max_offset_to_sync[txgoff];
573 }
574
575 /*
576 * We've already committed to copying this segment:
577 * we have allocated space elsewhere in the pool for
578 * it and have an IO outstanding to copy the data. We
579 * cannot free the space before the copy has
580 * completed, or else the copy IO might overwrite any
581 * new data. To free that space, we record the
582 * segment in the appropriate svr_frees tree and free
583 * the mapped space later, in the txg where we have
584 * completed the copy and synced the mapping (see
585 * vdev_mapping_sync).
586 */
587 range_tree_add(svr->svr_frees[txgoff],
588 offset, inflight_size);
589 size -= inflight_size;
590 offset += inflight_size;
591
592 /*
593 * This space is already accounted for as being
594 * done, because it is being copied in txg+i.
595 * However, if i!=0, then it is being copied in
596 * a future txg. If we crash after this txg
597 * syncs but before txg+i syncs, then the space
598 * will be free. Therefore we must account
599 * for the space being done in *this* txg
600 * (when it is freed) rather than the future txg
601 * (when it will be copied).
602 */
603 ASSERT3U(svr->svr_bytes_done[txgoff], >=,
604 inflight_size);
605 svr->svr_bytes_done[txgoff] -= inflight_size;
606 svr->svr_bytes_done[txg & TXG_MASK] += inflight_size;
607 }
608 }
609 ASSERT0(svr->svr_max_offset_to_sync[TXG_CLEAN(txg) & TXG_MASK]);
610
611 if (size > 0) {
612 /*
613 * The copy thread has not yet visited this offset. Ensure
614 * that it doesn't.
615 */
616
617 DTRACE_PROBE3(remove__free__unvisited,
618 spa_t *, spa,
619 uint64_t, offset,
620 uint64_t, size);
621
622 if (svr->svr_allocd_segs != NULL)
623 range_tree_clear(svr->svr_allocd_segs, offset, size);
624
625 /*
626 * Since we now do not need to copy this data, for
627 * accounting purposes we have done our job and can count
628 * it as completed.
629 */
630 svr->svr_bytes_done[txg & TXG_MASK] += size;
631 }
632 mutex_exit(&svr->svr_lock);
633
634 /*
635 * Now that we have dropped svr_lock, process the synced portion
636 * of this free.
637 */
638 if (synced_size > 0) {
639 vdev_indirect_mark_obsolete(vd, synced_offset, synced_size);
640
641 /*
642 * Note: this can only be called from syncing context,
643 * and the vdev_indirect_mapping is only changed from the
644 * sync thread, so we don't need svr_lock while doing
645 * metaslab_free_impl_cb.
646 */
647 boolean_t checkpoint = B_FALSE;
648 vdev_indirect_ops.vdev_op_remap(vd, synced_offset, synced_size,
649 metaslab_free_impl_cb, &checkpoint);
650 }
651 }
652
653 /*
654 * Stop an active removal and update the spa_removing phys.
655 */
656 static void
657 spa_finish_removal(spa_t *spa, dsl_scan_state_t state, dmu_tx_t *tx)
658 {
659 spa_vdev_removal_t *svr = spa->spa_vdev_removal;
660 ASSERT3U(dmu_tx_get_txg(tx), ==, spa_syncing_txg(spa));
661
662 /* Ensure the removal thread has completed before we free the svr. */
663 spa_vdev_remove_suspend(spa);
664
665 ASSERT(state == DSS_FINISHED || state == DSS_CANCELED);
666
667 if (state == DSS_FINISHED) {
668 spa_removing_phys_t *srp = &spa->spa_removing_phys;
669 vdev_t *vd = vdev_lookup_top(spa, svr->svr_vdev_id);
670 vdev_indirect_config_t *vic = &vd->vdev_indirect_config;
671
672 if (srp->sr_prev_indirect_vdev != UINT64_MAX) {
673 vdev_t *pvd = vdev_lookup_top(spa,
674 srp->sr_prev_indirect_vdev);
675 ASSERT3P(pvd->vdev_ops, ==, &vdev_indirect_ops);
676 }
677
678 vic->vic_prev_indirect_vdev = srp->sr_prev_indirect_vdev;
679 srp->sr_prev_indirect_vdev = vd->vdev_id;
680 }
681 spa->spa_removing_phys.sr_state = state;
682 spa->spa_removing_phys.sr_end_time = gethrestime_sec();
683
684 spa->spa_vdev_removal = NULL;
685 spa_vdev_removal_destroy(svr);
686
687 spa_sync_removing_state(spa, tx);
688
689 vdev_config_dirty(spa->spa_root_vdev);
690 }
691
692 static void
693 free_mapped_segment_cb(void *arg, uint64_t offset, uint64_t size)
694 {
695 vdev_t *vd = arg;
696 vdev_indirect_mark_obsolete(vd, offset, size);
697 boolean_t checkpoint = B_FALSE;
698 vdev_indirect_ops.vdev_op_remap(vd, offset, size,
699 metaslab_free_impl_cb, &checkpoint);
700 }
701
702 /*
703 * On behalf of the removal thread, syncs an incremental bit more of
704 * the indirect mapping to disk and updates the in-memory mapping.
705 * Called as a sync task in every txg that the removal thread makes progress.
706 */
707 static void
708 vdev_mapping_sync(void *arg, dmu_tx_t *tx)
709 {
710 spa_vdev_removal_t *svr = arg;
711 spa_t *spa = dmu_tx_pool(tx)->dp_spa;
712 vdev_t *vd = vdev_lookup_top(spa, svr->svr_vdev_id);
713 vdev_indirect_config_t *vic = &vd->vdev_indirect_config;
714 uint64_t txg = dmu_tx_get_txg(tx);
715 vdev_indirect_mapping_t *vim = vd->vdev_indirect_mapping;
716
717 ASSERT(vic->vic_mapping_object != 0);
718 ASSERT3U(txg, ==, spa_syncing_txg(spa));
719
720 vdev_indirect_mapping_add_entries(vim,
721 &svr->svr_new_segments[txg & TXG_MASK], tx);
722 vdev_indirect_births_add_entry(vd->vdev_indirect_births,
723 vdev_indirect_mapping_max_offset(vim), dmu_tx_get_txg(tx), tx);
724
725 /*
726 * Free the copied data for anything that was freed while the
727 * mapping entries were in flight.
728 */
729 mutex_enter(&svr->svr_lock);
730 range_tree_vacate(svr->svr_frees[txg & TXG_MASK],
731 free_mapped_segment_cb, vd);
732 ASSERT3U(svr->svr_max_offset_to_sync[txg & TXG_MASK], >=,
733 vdev_indirect_mapping_max_offset(vim));
734 svr->svr_max_offset_to_sync[txg & TXG_MASK] = 0;
735 mutex_exit(&svr->svr_lock);
736
737 spa_sync_removing_state(spa, tx);
738 }
739
740 typedef struct vdev_copy_segment_arg {
741 spa_t *vcsa_spa;
742 dva_t *vcsa_dest_dva;
743 uint64_t vcsa_txg;
744 range_tree_t *vcsa_obsolete_segs;
745 } vdev_copy_segment_arg_t;
746
747 static void
748 unalloc_seg(void *arg, uint64_t start, uint64_t size)
749 {
750 vdev_copy_segment_arg_t *vcsa = arg;
751 spa_t *spa = vcsa->vcsa_spa;
752 blkptr_t bp = { 0 };
753
754 BP_SET_BIRTH(&bp, TXG_INITIAL, TXG_INITIAL);
755 BP_SET_LSIZE(&bp, size);
756 BP_SET_PSIZE(&bp, size);
757 BP_SET_COMPRESS(&bp, ZIO_COMPRESS_OFF);
758 BP_SET_CHECKSUM(&bp, ZIO_CHECKSUM_OFF);
759 BP_SET_TYPE(&bp, DMU_OT_NONE);
760 BP_SET_LEVEL(&bp, 0);
761 BP_SET_DEDUP(&bp, 0);
762 BP_SET_BYTEORDER(&bp, ZFS_HOST_BYTEORDER);
763
764 DVA_SET_VDEV(&bp.blk_dva[0], DVA_GET_VDEV(vcsa->vcsa_dest_dva));
765 DVA_SET_OFFSET(&bp.blk_dva[0],
766 DVA_GET_OFFSET(vcsa->vcsa_dest_dva) + start);
767 DVA_SET_ASIZE(&bp.blk_dva[0], size);
768
769 zio_free(spa, vcsa->vcsa_txg, &bp);
770 }
771
772 /*
773 * All reads and writes associated with a call to spa_vdev_copy_segment()
774 * are done.
775 */
776 static void
777 spa_vdev_copy_segment_done(zio_t *zio)
778 {
779 vdev_copy_segment_arg_t *vcsa = zio->io_private;
780
781 range_tree_vacate(vcsa->vcsa_obsolete_segs,
782 unalloc_seg, vcsa);
783 range_tree_destroy(vcsa->vcsa_obsolete_segs);
784 kmem_free(vcsa, sizeof (*vcsa));
785
786 spa_config_exit(zio->io_spa, SCL_STATE, zio->io_spa);
787 }
788
789 /*
790 * The write of the new location is done.
791 */
792 static void
793 spa_vdev_copy_segment_write_done(zio_t *zio)
794 {
795 vdev_copy_arg_t *vca = zio->io_private;
796
797 abd_free(zio->io_abd);
798
799 mutex_enter(&vca->vca_lock);
800 vca->vca_outstanding_bytes -= zio->io_size;
801 cv_signal(&vca->vca_cv);
802 mutex_exit(&vca->vca_lock);
803 }
804
805 /*
806 * The read of the old location is done. The parent zio is the write to
807 * the new location. Allow it to start.
808 */
809 static void
810 spa_vdev_copy_segment_read_done(zio_t *zio)
811 {
812 zio_nowait(zio_unique_parent(zio));
813 }
814
815 /*
816 * If the old and new vdevs are mirrors, we will read both sides of the old
817 * mirror, and write each copy to the corresponding side of the new mirror.
818 * If the old and new vdevs have a different number of children, we will do
819 * this as best as possible. Since we aren't verifying checksums, this
820 * ensures that as long as there's a good copy of the data, we'll have a
821 * good copy after the removal, even if there's silent damage to one side
822 * of the mirror. If we're removing a mirror that has some silent damage,
823 * we'll have exactly the same damage in the new location (assuming that
824 * the new location is also a mirror).
825 *
826 * We accomplish this by creating a tree of zio_t's, with as many writes as
827 * there are "children" of the new vdev (a non-redundant vdev counts as one
828 * child, a 2-way mirror has 2 children, etc). Each write has an associated
829 * read from a child of the old vdev. Typically there will be the same
830 * number of children of the old and new vdevs. However, if there are more
831 * children of the new vdev, some child(ren) of the old vdev will be issued
832 * multiple reads. If there are more children of the old vdev, some copies
833 * will be dropped.
834 *
835 * For example, the tree of zio_t's for a 2-way mirror is:
836 *
837 * null
838 * / \
839 * write(new vdev, child 0) write(new vdev, child 1)
840 * | |
841 * read(old vdev, child 0) read(old vdev, child 1)
842 *
843 * Child zio's complete before their parents complete. However, zio's
844 * created with zio_vdev_child_io() may be issued before their children
845 * complete. In this case we need to make sure that the children (reads)
846 * complete before the parents (writes) are *issued*. We do this by not
847 * calling zio_nowait() on each write until its corresponding read has
848 * completed.
849 *
850 * The spa_config_lock must be held while zio's created by
851 * zio_vdev_child_io() are in progress, to ensure that the vdev tree does
852 * not change (e.g. due to a concurrent "zpool attach/detach"). The "null"
853 * zio is needed to release the spa_config_lock after all the reads and
854 * writes complete. (Note that we can't grab the config lock for each read,
855 * because it is not reentrant - we could deadlock with a thread waiting
856 * for a write lock.)
857 */
858 static void
859 spa_vdev_copy_one_child(vdev_copy_arg_t *vca, zio_t *nzio,
860 vdev_t *source_vd, uint64_t source_offset,
861 vdev_t *dest_child_vd, uint64_t dest_offset, int dest_id, uint64_t size)
862 {
863 ASSERT3U(spa_config_held(nzio->io_spa, SCL_ALL, RW_READER), !=, 0);
864
865 mutex_enter(&vca->vca_lock);
866 vca->vca_outstanding_bytes += size;
867 mutex_exit(&vca->vca_lock);
868
869 abd_t *abd = abd_alloc_for_io(size, B_FALSE);
870
871 vdev_t *source_child_vd;
872 if (source_vd->vdev_ops == &vdev_mirror_ops && dest_id != -1) {
873 /*
874 * Source and dest are both mirrors. Copy from the same
875 * child id as we are copying to (wrapping around if there
876 * are more dest children than source children).
877 */
878 source_child_vd =
879 source_vd->vdev_child[dest_id % source_vd->vdev_children];
880 } else {
881 source_child_vd = source_vd;
882 }
883
884 zio_t *write_zio = zio_vdev_child_io(nzio, NULL,
885 dest_child_vd, dest_offset, abd, size,
886 ZIO_TYPE_WRITE, ZIO_PRIORITY_REMOVAL,
887 ZIO_FLAG_CANFAIL,
888 spa_vdev_copy_segment_write_done, vca);
889
890 zio_nowait(zio_vdev_child_io(write_zio, NULL,
891 source_child_vd, source_offset, abd, size,
892 ZIO_TYPE_READ, ZIO_PRIORITY_REMOVAL,
893 ZIO_FLAG_CANFAIL,
894 spa_vdev_copy_segment_read_done, vca));
895 }
896
897 /*
898 * Allocate a new location for this segment, and create the zio_t's to
899 * read from the old location and write to the new location.
900 */
901 static int
902 spa_vdev_copy_segment(vdev_t *vd, range_tree_t *segs,
903 uint64_t maxalloc, uint64_t txg,
904 vdev_copy_arg_t *vca, zio_alloc_list_t *zal)
905 {
906 metaslab_group_t *mg = vd->vdev_mg;
907 spa_t *spa = vd->vdev_spa;
908 spa_vdev_removal_t *svr = spa->spa_vdev_removal;
909 vdev_indirect_mapping_entry_t *entry;
910 dva_t dst = { 0 };
911 uint64_t start = range_tree_min(segs);
912
913 ASSERT3U(maxalloc, <=, SPA_MAXBLOCKSIZE);
914
915 uint64_t size = range_tree_span(segs);
916 if (range_tree_span(segs) > maxalloc) {
917 /*
918 * We can't allocate all the segments. Prefer to end
919 * the allocation at the end of a segment, thus avoiding
920 * additional split blocks.
921 */
922 range_seg_t search;
923 avl_index_t where;
924 search.rs_start = start + maxalloc;
925 search.rs_end = search.rs_start;
926 range_seg_t *rs = avl_find(&segs->rt_root, &search, &where);
927 if (rs == NULL) {
928 rs = avl_nearest(&segs->rt_root, where, AVL_BEFORE);
929 } else {
930 rs = AVL_PREV(&segs->rt_root, rs);
931 }
932 if (rs != NULL) {
933 size = rs->rs_end - start;
934 } else {
935 /*
936 * There are no segments that end before maxalloc.
937 * I.e. the first segment is larger than maxalloc,
938 * so we must split it.
939 */
940 size = maxalloc;
941 }
942 }
943 ASSERT3U(size, <=, maxalloc);
944
945 /*
946 * An allocation class might not have any remaining vdevs or space
947 */
948 metaslab_class_t *mc = mg->mg_class;
949 if (mc != spa_normal_class(spa) && mc->mc_groups <= 1)
950 mc = spa_normal_class(spa);
951 int error = metaslab_alloc_dva(spa, mc, size, &dst, 0, NULL, txg, 0,
952 zal, 0);
953 if (error == ENOSPC && mc != spa_normal_class(spa)) {
954 error = metaslab_alloc_dva(spa, spa_normal_class(spa), size,
955 &dst, 0, NULL, txg, 0, zal, 0);
956 }
957 if (error != 0)
958 return (error);
959
960 /*
961 * Determine the ranges that are not actually needed. Offsets are
962 * relative to the start of the range to be copied (i.e. relative to the
963 * local variable "start").
964 */
965 range_tree_t *obsolete_segs = range_tree_create(NULL, NULL);
966
967 range_seg_t *rs = avl_first(&segs->rt_root);
968 ASSERT3U(rs->rs_start, ==, start);
969 uint64_t prev_seg_end = rs->rs_end;
970 while ((rs = AVL_NEXT(&segs->rt_root, rs)) != NULL) {
971 if (rs->rs_start >= start + size) {
972 break;
973 } else {
974 range_tree_add(obsolete_segs,
975 prev_seg_end - start,
976 rs->rs_start - prev_seg_end);
977 }
978 prev_seg_end = rs->rs_end;
979 }
980 /* We don't end in the middle of an obsolete range */
981 ASSERT3U(start + size, <=, prev_seg_end);
982
983 range_tree_clear(segs, start, size);
984
985 /*
986 * We can't have any padding of the allocated size, otherwise we will
987 * misunderstand what's allocated, and the size of the mapping.
988 * The caller ensures this will be true by passing in a size that is
989 * aligned to the worst (highest) ashift in the pool.
990 */
991 ASSERT3U(DVA_GET_ASIZE(&dst), ==, size);
992
993 entry = kmem_zalloc(sizeof (vdev_indirect_mapping_entry_t), KM_SLEEP);
994 DVA_MAPPING_SET_SRC_OFFSET(&entry->vime_mapping, start);
995 entry->vime_mapping.vimep_dst = dst;
996 if (spa_feature_is_enabled(spa, SPA_FEATURE_OBSOLETE_COUNTS)) {
997 entry->vime_obsolete_count = range_tree_space(obsolete_segs);
998 }
999
1000 vdev_copy_segment_arg_t *vcsa = kmem_zalloc(sizeof (*vcsa), KM_SLEEP);
1001 vcsa->vcsa_dest_dva = &entry->vime_mapping.vimep_dst;
1002 vcsa->vcsa_obsolete_segs = obsolete_segs;
1003 vcsa->vcsa_spa = spa;
1004 vcsa->vcsa_txg = txg;
1005
1006 /*
1007 * See comment before spa_vdev_copy_one_child().
1008 */
1009 spa_config_enter(spa, SCL_STATE, spa, RW_READER);
1010 zio_t *nzio = zio_null(spa->spa_txg_zio[txg & TXG_MASK], spa, NULL,
1011 spa_vdev_copy_segment_done, vcsa, 0);
1012 vdev_t *dest_vd = vdev_lookup_top(spa, DVA_GET_VDEV(&dst));
1013 if (dest_vd->vdev_ops == &vdev_mirror_ops) {
1014 for (int i = 0; i < dest_vd->vdev_children; i++) {
1015 vdev_t *child = dest_vd->vdev_child[i];
1016 spa_vdev_copy_one_child(vca, nzio, vd, start,
1017 child, DVA_GET_OFFSET(&dst), i, size);
1018 }
1019 } else {
1020 spa_vdev_copy_one_child(vca, nzio, vd, start,
1021 dest_vd, DVA_GET_OFFSET(&dst), -1, size);
1022 }
1023 zio_nowait(nzio);
1024
1025 list_insert_tail(&svr->svr_new_segments[txg & TXG_MASK], entry);
1026 ASSERT3U(start + size, <=, vd->vdev_ms_count << vd->vdev_ms_shift);
1027 vdev_dirty(vd, 0, NULL, txg);
1028
1029 return (0);
1030 }
1031
1032 /*
1033 * Complete the removal of a toplevel vdev. This is called as a
1034 * synctask in the same txg that we will sync out the new config (to the
1035 * MOS object) which indicates that this vdev is indirect.
1036 */
1037 static void
1038 vdev_remove_complete_sync(void *arg, dmu_tx_t *tx)
1039 {
1040 spa_vdev_removal_t *svr = arg;
1041 spa_t *spa = dmu_tx_pool(tx)->dp_spa;
1042 vdev_t *vd = vdev_lookup_top(spa, svr->svr_vdev_id);
1043
1044 ASSERT3P(vd->vdev_ops, ==, &vdev_indirect_ops);
1045
1046 for (int i = 0; i < TXG_SIZE; i++) {
1047 ASSERT0(svr->svr_bytes_done[i]);
1048 }
1049
1050 ASSERT3U(spa->spa_removing_phys.sr_copied, ==,
1051 spa->spa_removing_phys.sr_to_copy);
1052
1053 vdev_destroy_spacemaps(vd, tx);
1054
1055 /* destroy leaf zaps, if any */
1056 ASSERT3P(svr->svr_zaplist, !=, NULL);
1057 for (nvpair_t *pair = nvlist_next_nvpair(svr->svr_zaplist, NULL);
1058 pair != NULL;
1059 pair = nvlist_next_nvpair(svr->svr_zaplist, pair)) {
1060 vdev_destroy_unlink_zap(vd, fnvpair_value_uint64(pair), tx);
1061 }
1062 fnvlist_free(svr->svr_zaplist);
1063
1064 spa_finish_removal(dmu_tx_pool(tx)->dp_spa, DSS_FINISHED, tx);
1065 /* vd->vdev_path is not available here */
1066 spa_history_log_internal(spa, "vdev remove completed", tx,
1067 "%s vdev %llu", spa_name(spa), vd->vdev_id);
1068 }
1069
1070 static void
1071 vdev_remove_enlist_zaps(vdev_t *vd, nvlist_t *zlist)
1072 {
1073 ASSERT3P(zlist, !=, NULL);
1074 ASSERT3P(vd->vdev_ops, !=, &vdev_raidz_ops);
1075
1076 if (vd->vdev_leaf_zap != 0) {
1077 char zkey[32];
1078 (void) snprintf(zkey, sizeof (zkey), "%s-%"PRIu64,
1079 VDEV_REMOVAL_ZAP_OBJS, vd->vdev_leaf_zap);
1080 fnvlist_add_uint64(zlist, zkey, vd->vdev_leaf_zap);
1081 }
1082
1083 for (uint64_t id = 0; id < vd->vdev_children; id++) {
1084 vdev_remove_enlist_zaps(vd->vdev_child[id], zlist);
1085 }
1086 }
1087
1088 static void
1089 vdev_remove_replace_with_indirect(vdev_t *vd, uint64_t txg)
1090 {
1091 vdev_t *ivd;
1092 dmu_tx_t *tx;
1093 spa_t *spa = vd->vdev_spa;
1094 spa_vdev_removal_t *svr = spa->spa_vdev_removal;
1095
1096 /*
1097 * First, build a list of leaf zaps to be destroyed.
1098 * This is passed to the sync context thread,
1099 * which does the actual unlinking.
1100 */
1101 svr->svr_zaplist = fnvlist_alloc();
1102 vdev_remove_enlist_zaps(vd, svr->svr_zaplist);
1103
1104 ivd = vdev_add_parent(vd, &vdev_indirect_ops);
1105 ivd->vdev_removing = 0;
1106
1107 vd->vdev_leaf_zap = 0;
1108
1109 vdev_remove_child(ivd, vd);
1110 vdev_compact_children(ivd);
1111
1112 ASSERT(!list_link_active(&vd->vdev_state_dirty_node));
1113
1114 tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
1115 dsl_sync_task_nowait(spa->spa_dsl_pool, vdev_remove_complete_sync, svr,
1116 0, ZFS_SPACE_CHECK_NONE, tx);
1117 dmu_tx_commit(tx);
1118
1119 /*
1120 * Indicate that this thread has exited.
1121 * After this, we can not use svr.
1122 */
1123 mutex_enter(&svr->svr_lock);
1124 svr->svr_thread = NULL;
1125 cv_broadcast(&svr->svr_cv);
1126 mutex_exit(&svr->svr_lock);
1127 }
1128
1129 /*
1130 * Complete the removal of a toplevel vdev. This is called in open
1131 * context by the removal thread after we have copied all vdev's data.
1132 */
1133 static void
1134 vdev_remove_complete(spa_t *spa)
1135 {
1136 uint64_t txg;
1137
1138 /*
1139 * Wait for any deferred frees to be synced before we call
1140 * vdev_metaslab_fini()
1141 */
1142 txg_wait_synced(spa->spa_dsl_pool, 0);
1143 txg = spa_vdev_enter(spa);
1144 vdev_t *vd = vdev_lookup_top(spa, spa->spa_vdev_removal->svr_vdev_id);
1145 ASSERT3P(vd->vdev_initialize_thread, ==, NULL);
1146
1147 sysevent_t *ev = spa_event_create(spa, vd, NULL,
1148 ESC_ZFS_VDEV_REMOVE_DEV);
1149
1150 zfs_dbgmsg("finishing device removal for vdev %llu in txg %llu",
1151 vd->vdev_id, txg);
1152
1153 /*
1154 * Discard allocation state.
1155 */
1156 if (vd->vdev_mg != NULL) {
1157 vdev_metaslab_fini(vd);
1158 metaslab_group_destroy(vd->vdev_mg);
1159 vd->vdev_mg = NULL;
1160 }
1161 ASSERT0(vd->vdev_stat.vs_space);
1162 ASSERT0(vd->vdev_stat.vs_dspace);
1163
1164 vdev_remove_replace_with_indirect(vd, txg);
1165
1166 /*
1167 * We now release the locks, allowing spa_sync to run and finish the
1168 * removal via vdev_remove_complete_sync in syncing context.
1169 *
1170 * Note that we hold on to the vdev_t that has been replaced. Since
1171 * it isn't part of the vdev tree any longer, it can't be concurrently
1172 * manipulated, even while we don't have the config lock.
1173 */
1174 (void) spa_vdev_exit(spa, NULL, txg, 0);
1175
1176 /*
1177 * Top ZAP should have been transferred to the indirect vdev in
1178 * vdev_remove_replace_with_indirect.
1179 */
1180 ASSERT0(vd->vdev_top_zap);
1181
1182 /*
1183 * Leaf ZAP should have been moved in vdev_remove_replace_with_indirect.
1184 */
1185 ASSERT0(vd->vdev_leaf_zap);
1186
1187 txg = spa_vdev_enter(spa);
1188 (void) vdev_label_init(vd, 0, VDEV_LABEL_REMOVE);
1189 /*
1190 * Request to update the config and the config cachefile.
1191 */
1192 vdev_config_dirty(spa->spa_root_vdev);
1193 (void) spa_vdev_exit(spa, vd, txg, 0);
1194
1195 spa_event_post(ev);
1196 }
1197
1198 /*
1199 * Evacuates a segment of size at most max_alloc from the vdev
1200 * via repeated calls to spa_vdev_copy_segment. If an allocation
1201 * fails, the pool is probably too fragmented to handle such a
1202 * large size, so decrease max_alloc so that the caller will not try
1203 * this size again this txg.
1204 */
1205 static void
1206 spa_vdev_copy_impl(vdev_t *vd, spa_vdev_removal_t *svr, vdev_copy_arg_t *vca,
1207 uint64_t *max_alloc, dmu_tx_t *tx)
1208 {
1209 uint64_t txg = dmu_tx_get_txg(tx);
1210 spa_t *spa = dmu_tx_pool(tx)->dp_spa;
1211
1212 mutex_enter(&svr->svr_lock);
1213
1214 /*
1215 * Determine how big of a chunk to copy. We can allocate up
1216 * to max_alloc bytes, and we can span up to vdev_removal_max_span
1217 * bytes of unallocated space at a time. "segs" will track the
1218 * allocated segments that we are copying. We may also be copying
1219 * free segments (of up to vdev_removal_max_span bytes).
1220 */
1221 range_tree_t *segs = range_tree_create(NULL, NULL);
1222 for (;;) {
1223 range_seg_t *rs = avl_first(&svr->svr_allocd_segs->rt_root);
1224 if (rs == NULL)
1225 break;
1226
1227 uint64_t seg_length;
1228
1229 if (range_tree_is_empty(segs)) {
1230 /* need to truncate the first seg based on max_alloc */
1231 seg_length =
1232 MIN(rs->rs_end - rs->rs_start, *max_alloc);
1233 } else {
1234 if (rs->rs_start - range_tree_max(segs) >
1235 vdev_removal_max_span) {
1236 /*
1237 * Including this segment would cause us to
1238 * copy a larger unneeded chunk than is allowed.
1239 */
1240 break;
1241 } else if (rs->rs_end - range_tree_min(segs) >
1242 *max_alloc) {
1243 /*
1244 * This additional segment would extend past
1245 * max_alloc. Rather than splitting this
1246 * segment, leave it for the next mapping.
1247 */
1248 break;
1249 } else {
1250 seg_length = rs->rs_end - rs->rs_start;
1251 }
1252 }
1253
1254 range_tree_add(segs, rs->rs_start, seg_length);
1255 range_tree_remove(svr->svr_allocd_segs,
1256 rs->rs_start, seg_length);
1257 }
1258
1259 if (range_tree_is_empty(segs)) {
1260 mutex_exit(&svr->svr_lock);
1261 range_tree_destroy(segs);
1262 return;
1263 }
1264
1265 if (svr->svr_max_offset_to_sync[txg & TXG_MASK] == 0) {
1266 dsl_sync_task_nowait(dmu_tx_pool(tx), vdev_mapping_sync,
1267 svr, 0, ZFS_SPACE_CHECK_NONE, tx);
1268 }
1269
1270 svr->svr_max_offset_to_sync[txg & TXG_MASK] = range_tree_max(segs);
1271
1272 /*
1273 * Note: this is the amount of *allocated* space
1274 * that we are taking care of each txg.
1275 */
1276 svr->svr_bytes_done[txg & TXG_MASK] += range_tree_space(segs);
1277
1278 mutex_exit(&svr->svr_lock);
1279
1280 zio_alloc_list_t zal;
1281 metaslab_trace_init(&zal);
1282 uint64_t thismax = SPA_MAXBLOCKSIZE;
1283 while (!range_tree_is_empty(segs)) {
1284 int error = spa_vdev_copy_segment(vd,
1285 segs, thismax, txg, vca, &zal);
1286
1287 if (error == ENOSPC) {
1288 /*
1289 * Cut our segment in half, and don't try this
1290 * segment size again this txg. Note that the
1291 * allocation size must be aligned to the highest
1292 * ashift in the pool, so that the allocation will
1293 * not be padded out to a multiple of the ashift,
1294 * which could cause us to think that this mapping
1295 * is larger than we intended.
1296 */
1297 ASSERT3U(spa->spa_max_ashift, >=, SPA_MINBLOCKSHIFT);
1298 ASSERT3U(spa->spa_max_ashift, ==, spa->spa_min_ashift);
1299 uint64_t attempted =
1300 MIN(range_tree_span(segs), thismax);
1301 thismax = P2ROUNDUP(attempted / 2,
1302 1 << spa->spa_max_ashift);
1303 /*
1304 * The minimum-size allocation can not fail.
1305 */
1306 ASSERT3U(attempted, >, 1 << spa->spa_max_ashift);
1307 *max_alloc = attempted - (1 << spa->spa_max_ashift);
1308 } else {
1309 ASSERT0(error);
1310
1311 /*
1312 * We've performed an allocation, so reset the
1313 * alloc trace list.
1314 */
1315 metaslab_trace_fini(&zal);
1316 metaslab_trace_init(&zal);
1317 }
1318 }
1319 metaslab_trace_fini(&zal);
1320 range_tree_destroy(segs);
1321 }
1322
1323 /*
1324 * The removal thread operates in open context. It iterates over all
1325 * allocated space in the vdev, by loading each metaslab's spacemap.
1326 * For each contiguous segment of allocated space (capping the segment
1327 * size at SPA_MAXBLOCKSIZE), we:
1328 * - Allocate space for it on another vdev.
1329 * - Create a new mapping from the old location to the new location
1330 * (as a record in svr_new_segments).
1331 * - Initiate a logical read zio to get the data off the removing disk.
1332 * - In the read zio's done callback, initiate a logical write zio to
1333 * write it to the new vdev.
1334 * Note that all of this will take effect when a particular TXG syncs.
1335 * The sync thread ensures that all the phys reads and writes for the syncing
1336 * TXG have completed (see spa_txg_zio) and writes the new mappings to disk
1337 * (see vdev_mapping_sync()).
1338 */
1339 static void
1340 spa_vdev_remove_thread(void *arg)
1341 {
1342 spa_t *spa = arg;
1343 spa_vdev_removal_t *svr = spa->spa_vdev_removal;
1344 vdev_copy_arg_t vca;
1345 uint64_t max_alloc = zfs_remove_max_segment;
1346 uint64_t last_txg = 0;
1347
1348 spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
1349 vdev_t *vd = vdev_lookup_top(spa, svr->svr_vdev_id);
1350 vdev_indirect_mapping_t *vim = vd->vdev_indirect_mapping;
1351 uint64_t start_offset = vdev_indirect_mapping_max_offset(vim);
1352
1353 ASSERT3P(vd->vdev_ops, !=, &vdev_indirect_ops);
1354 ASSERT(vdev_is_concrete(vd));
1355 ASSERT(vd->vdev_removing);
1356 ASSERT(vd->vdev_indirect_config.vic_mapping_object != 0);
1357 ASSERT(vim != NULL);
1358
1359 mutex_init(&vca.vca_lock, NULL, MUTEX_DEFAULT, NULL);
1360 cv_init(&vca.vca_cv, NULL, CV_DEFAULT, NULL);
1361 vca.vca_outstanding_bytes = 0;
1362
1363 mutex_enter(&svr->svr_lock);
1364
1365 /*
1366 * Start from vim_max_offset so we pick up where we left off
1367 * if we are restarting the removal after opening the pool.
1368 */
1369 uint64_t msi;
1370 for (msi = start_offset >> vd->vdev_ms_shift;
1371 msi < vd->vdev_ms_count && !svr->svr_thread_exit; msi++) {
1372 metaslab_t *msp = vd->vdev_ms[msi];
1373 ASSERT3U(msi, <=, vd->vdev_ms_count);
1374
1375 ASSERT0(range_tree_space(svr->svr_allocd_segs));
1376
1377 mutex_enter(&msp->ms_sync_lock);
1378 mutex_enter(&msp->ms_lock);
1379
1380 /*
1381 * Assert nothing in flight -- ms_*tree is empty.
1382 */
1383 for (int i = 0; i < TXG_SIZE; i++) {
1384 ASSERT0(range_tree_space(msp->ms_allocating[i]));
1385 }
1386
1387 /*
1388 * If the metaslab has ever been allocated from (ms_sm!=NULL),
1389 * read the allocated segments from the space map object
1390 * into svr_allocd_segs. Since we do this while holding
1391 * svr_lock and ms_sync_lock, concurrent frees (which
1392 * would have modified the space map) will wait for us
1393 * to finish loading the spacemap, and then take the
1394 * appropriate action (see free_from_removing_vdev()).
1395 */
1396 if (msp->ms_sm != NULL) {
1397 VERIFY0(space_map_load(msp->ms_sm,
1398 svr->svr_allocd_segs, SM_ALLOC));
1399
1400 range_tree_walk(msp->ms_freeing,
1401 range_tree_remove, svr->svr_allocd_segs);
1402
1403 /*
1404 * When we are resuming from a paused removal (i.e.
1405 * when importing a pool with a removal in progress),
1406 * discard any state that we have already processed.
1407 */
1408 range_tree_clear(svr->svr_allocd_segs, 0, start_offset);
1409 }
1410 mutex_exit(&msp->ms_lock);
1411 mutex_exit(&msp->ms_sync_lock);
1412
1413 vca.vca_msp = msp;
1414 zfs_dbgmsg("copying %llu segments for metaslab %llu",
1415 avl_numnodes(&svr->svr_allocd_segs->rt_root),
1416 msp->ms_id);
1417
1418 while (!svr->svr_thread_exit &&
1419 !range_tree_is_empty(svr->svr_allocd_segs)) {
1420
1421 mutex_exit(&svr->svr_lock);
1422
1423 /*
1424 * We need to periodically drop the config lock so that
1425 * writers can get in. Additionally, we can't wait
1426 * for a txg to sync while holding a config lock
1427 * (since a waiting writer could cause a 3-way deadlock
1428 * with the sync thread, which also gets a config
1429 * lock for reader). So we can't hold the config lock
1430 * while calling dmu_tx_assign().
1431 */
1432 spa_config_exit(spa, SCL_CONFIG, FTAG);
1433
1434 /*
1435 * This delay will pause the removal around the point
1436 * specified by zfs_remove_max_bytes_pause. We do this
1437 * solely from the test suite or during debugging.
1438 */
1439 uint64_t bytes_copied =
1440 spa->spa_removing_phys.sr_copied;
1441 for (int i = 0; i < TXG_SIZE; i++)
1442 bytes_copied += svr->svr_bytes_done[i];
1443 while (zfs_remove_max_bytes_pause <= bytes_copied &&
1444 !svr->svr_thread_exit)
1445 delay(hz);
1446
1447 mutex_enter(&vca.vca_lock);
1448 while (vca.vca_outstanding_bytes >
1449 zfs_remove_max_copy_bytes) {
1450 cv_wait(&vca.vca_cv, &vca.vca_lock);
1451 }
1452 mutex_exit(&vca.vca_lock);
1453
1454 dmu_tx_t *tx =
1455 dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir);
1456
1457 VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
1458 uint64_t txg = dmu_tx_get_txg(tx);
1459
1460 /*
1461 * Reacquire the vdev_config lock. The vdev_t
1462 * that we're removing may have changed, e.g. due
1463 * to a vdev_attach or vdev_detach.
1464 */
1465 spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
1466 vd = vdev_lookup_top(spa, svr->svr_vdev_id);
1467
1468 if (txg != last_txg)
1469 max_alloc = zfs_remove_max_segment;
1470 last_txg = txg;
1471
1472 spa_vdev_copy_impl(vd, svr, &vca, &max_alloc, tx);
1473
1474 dmu_tx_commit(tx);
1475 mutex_enter(&svr->svr_lock);
1476 }
1477 }
1478
1479 mutex_exit(&svr->svr_lock);
1480
1481 spa_config_exit(spa, SCL_CONFIG, FTAG);
1482
1483 /*
1484 * Wait for all copies to finish before cleaning up the vca.
1485 */
1486 txg_wait_synced(spa->spa_dsl_pool, 0);
1487 ASSERT0(vca.vca_outstanding_bytes);
1488
1489 mutex_destroy(&vca.vca_lock);
1490 cv_destroy(&vca.vca_cv);
1491
1492 if (svr->svr_thread_exit) {
1493 mutex_enter(&svr->svr_lock);
1494 range_tree_vacate(svr->svr_allocd_segs, NULL, NULL);
1495 svr->svr_thread = NULL;
1496 cv_broadcast(&svr->svr_cv);
1497 mutex_exit(&svr->svr_lock);
1498 } else {
1499 ASSERT0(range_tree_space(svr->svr_allocd_segs));
1500 vdev_remove_complete(spa);
1501 }
1502 }
1503
1504 void
1505 spa_vdev_remove_suspend(spa_t *spa)
1506 {
1507 spa_vdev_removal_t *svr = spa->spa_vdev_removal;
1508
1509 if (svr == NULL)
1510 return;
1511
1512 mutex_enter(&svr->svr_lock);
1513 svr->svr_thread_exit = B_TRUE;
1514 while (svr->svr_thread != NULL)
1515 cv_wait(&svr->svr_cv, &svr->svr_lock);
1516 svr->svr_thread_exit = B_FALSE;
1517 mutex_exit(&svr->svr_lock);
1518 }
1519
1520 /* ARGSUSED */
1521 static int
1522 spa_vdev_remove_cancel_check(void *arg, dmu_tx_t *tx)
1523 {
1524 spa_t *spa = dmu_tx_pool(tx)->dp_spa;
1525
1526 if (spa->spa_vdev_removal == NULL)
1527 return (ENOTACTIVE);
1528 return (0);
1529 }
1530
1531 /*
1532 * Cancel a removal by freeing all entries from the partial mapping
1533 * and marking the vdev as no longer being removing.
1534 */
1535 /* ARGSUSED */
1536 static void
1537 spa_vdev_remove_cancel_sync(void *arg, dmu_tx_t *tx)
1538 {
1539 spa_t *spa = dmu_tx_pool(tx)->dp_spa;
1540 spa_vdev_removal_t *svr = spa->spa_vdev_removal;
1541 vdev_t *vd = vdev_lookup_top(spa, svr->svr_vdev_id);
1542 vdev_indirect_config_t *vic = &vd->vdev_indirect_config;
1543 vdev_indirect_mapping_t *vim = vd->vdev_indirect_mapping;
1544 objset_t *mos = spa->spa_meta_objset;
1545
1546 ASSERT3P(svr->svr_thread, ==, NULL);
1547
1548 spa_feature_decr(spa, SPA_FEATURE_DEVICE_REMOVAL, tx);
1549 if (vdev_obsolete_counts_are_precise(vd)) {
1550 spa_feature_decr(spa, SPA_FEATURE_OBSOLETE_COUNTS, tx);
1551 VERIFY0(zap_remove(spa->spa_meta_objset, vd->vdev_top_zap,
1552 VDEV_TOP_ZAP_OBSOLETE_COUNTS_ARE_PRECISE, tx));
1553 }
1554
1555 if (vdev_obsolete_sm_object(vd) != 0) {
1556 ASSERT(vd->vdev_obsolete_sm != NULL);
1557 ASSERT3U(vdev_obsolete_sm_object(vd), ==,
1558 space_map_object(vd->vdev_obsolete_sm));
1559
1560 space_map_free(vd->vdev_obsolete_sm, tx);
1561 VERIFY0(zap_remove(spa->spa_meta_objset, vd->vdev_top_zap,
1562 VDEV_TOP_ZAP_INDIRECT_OBSOLETE_SM, tx));
1563 space_map_close(vd->vdev_obsolete_sm);
1564 vd->vdev_obsolete_sm = NULL;
1565 spa_feature_decr(spa, SPA_FEATURE_OBSOLETE_COUNTS, tx);
1566 }
1567 for (int i = 0; i < TXG_SIZE; i++) {
1568 ASSERT(list_is_empty(&svr->svr_new_segments[i]));
1569 ASSERT3U(svr->svr_max_offset_to_sync[i], <=,
1570 vdev_indirect_mapping_max_offset(vim));
1571 }
1572
1573 for (uint64_t msi = 0; msi < vd->vdev_ms_count; msi++) {
1574 metaslab_t *msp = vd->vdev_ms[msi];
1575
1576 if (msp->ms_start >= vdev_indirect_mapping_max_offset(vim))
1577 break;
1578
1579 ASSERT0(range_tree_space(svr->svr_allocd_segs));
1580
1581 mutex_enter(&msp->ms_lock);
1582
1583 /*
1584 * Assert nothing in flight -- ms_*tree is empty.
1585 */
1586 for (int i = 0; i < TXG_SIZE; i++)
1587 ASSERT0(range_tree_space(msp->ms_allocating[i]));
1588 for (int i = 0; i < TXG_DEFER_SIZE; i++)
1589 ASSERT0(range_tree_space(msp->ms_defer[i]));
1590 ASSERT0(range_tree_space(msp->ms_freed));
1591
1592 if (msp->ms_sm != NULL) {
1593 mutex_enter(&svr->svr_lock);
1594 VERIFY0(space_map_load(msp->ms_sm,
1595 svr->svr_allocd_segs, SM_ALLOC));
1596 range_tree_walk(msp->ms_freeing,
1597 range_tree_remove, svr->svr_allocd_segs);
1598
1599 /*
1600 * Clear everything past what has been synced,
1601 * because we have not allocated mappings for it yet.
1602 */
1603 uint64_t syncd = vdev_indirect_mapping_max_offset(vim);
1604 uint64_t sm_end = msp->ms_sm->sm_start +
1605 msp->ms_sm->sm_size;
1606 if (sm_end > syncd)
1607 range_tree_clear(svr->svr_allocd_segs,
1608 syncd, sm_end - syncd);
1609
1610 mutex_exit(&svr->svr_lock);
1611 }
1612 mutex_exit(&msp->ms_lock);
1613
1614 mutex_enter(&svr->svr_lock);
1615 range_tree_vacate(svr->svr_allocd_segs,
1616 free_mapped_segment_cb, vd);
1617 mutex_exit(&svr->svr_lock);
1618 }
1619
1620 /*
1621 * Note: this must happen after we invoke free_mapped_segment_cb,
1622 * because it adds to the obsolete_segments.
1623 */
1624 range_tree_vacate(vd->vdev_obsolete_segments, NULL, NULL);
1625
1626 ASSERT3U(vic->vic_mapping_object, ==,
1627 vdev_indirect_mapping_object(vd->vdev_indirect_mapping));
1628 vdev_indirect_mapping_close(vd->vdev_indirect_mapping);
1629 vd->vdev_indirect_mapping = NULL;
1630 vdev_indirect_mapping_free(mos, vic->vic_mapping_object, tx);
1631 vic->vic_mapping_object = 0;
1632
1633 ASSERT3U(vic->vic_births_object, ==,
1634 vdev_indirect_births_object(vd->vdev_indirect_births));
1635 vdev_indirect_births_close(vd->vdev_indirect_births);
1636 vd->vdev_indirect_births = NULL;
1637 vdev_indirect_births_free(mos, vic->vic_births_object, tx);
1638 vic->vic_births_object = 0;
1639
1640 /*
1641 * We may have processed some frees from the removing vdev in this
1642 * txg, thus increasing svr_bytes_done; discard that here to
1643 * satisfy the assertions in spa_vdev_removal_destroy().
1644 * Note that future txg's can not have any bytes_done, because
1645 * future TXG's are only modified from open context, and we have
1646 * already shut down the copying thread.
1647 */
1648 svr->svr_bytes_done[dmu_tx_get_txg(tx) & TXG_MASK] = 0;
1649 spa_finish_removal(spa, DSS_CANCELED, tx);
1650
1651 vd->vdev_removing = B_FALSE;
1652 vdev_config_dirty(vd);
1653
1654 zfs_dbgmsg("canceled device removal for vdev %llu in %llu",
1655 vd->vdev_id, dmu_tx_get_txg(tx));
1656 spa_history_log_internal(spa, "vdev remove canceled", tx,
1657 "%s vdev %llu %s", spa_name(spa),
1658 vd->vdev_id, (vd->vdev_path != NULL) ? vd->vdev_path : "-");
1659 }
1660
1661 int
1662 spa_vdev_remove_cancel(spa_t *spa)
1663 {
1664 spa_vdev_remove_suspend(spa);
1665
1666 if (spa->spa_vdev_removal == NULL)
1667 return (ENOTACTIVE);
1668
1669 uint64_t vdid = spa->spa_vdev_removal->svr_vdev_id;
1670
1671 int error = dsl_sync_task(spa->spa_name, spa_vdev_remove_cancel_check,
1672 spa_vdev_remove_cancel_sync, NULL, 0,
1673 ZFS_SPACE_CHECK_EXTRA_RESERVED);
1674
1675 if (error == 0) {
1676 spa_config_enter(spa, SCL_ALLOC | SCL_VDEV, FTAG, RW_WRITER);
1677 vdev_t *vd = vdev_lookup_top(spa, vdid);
1678 metaslab_group_activate(vd->vdev_mg);
1679 spa_config_exit(spa, SCL_ALLOC | SCL_VDEV, FTAG);
1680 }
1681
1682 return (error);
1683 }
1684
1685 void
1686 svr_sync(spa_t *spa, dmu_tx_t *tx)
1687 {
1688 spa_vdev_removal_t *svr = spa->spa_vdev_removal;
1689 int txgoff = dmu_tx_get_txg(tx) & TXG_MASK;
1690
1691 /*
1692 * This check is necessary so that we do not dirty the
1693 * DIRECTORY_OBJECT via spa_sync_removing_state() when there
1694 * is nothing to do. Dirtying it every time would prevent us
1695 * from syncing-to-convergence.
1696 */
1697 if (svr->svr_bytes_done[txgoff] == 0)
1698 return;
1699
1700 /*
1701 * Update progress accounting.
1702 */
1703 spa->spa_removing_phys.sr_copied += svr->svr_bytes_done[txgoff];
1704 svr->svr_bytes_done[txgoff] = 0;
1705
1706 spa_sync_removing_state(spa, tx);
1707 }
1708
1709 static void
1710 vdev_remove_make_hole_and_free(vdev_t *vd)
1711 {
1712 uint64_t id = vd->vdev_id;
1713 spa_t *spa = vd->vdev_spa;
1714 vdev_t *rvd = spa->spa_root_vdev;
1715 boolean_t last_vdev = (id == (rvd->vdev_children - 1));
1716
1717 ASSERT(MUTEX_HELD(&spa_namespace_lock));
1718 ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
1719
1720 vdev_free(vd);
1721
1722 if (last_vdev) {
1723 vdev_compact_children(rvd);
1724 } else {
1725 vd = vdev_alloc_common(spa, id, 0, &vdev_hole_ops);
1726 vdev_add_child(rvd, vd);
1727 }
1728 vdev_config_dirty(rvd);
1729
1730 /*
1731 * Reassess the health of our root vdev.
1732 */
1733 vdev_reopen(rvd);
1734 }
1735
1736 /*
1737 * Remove a log device. The config lock is held for the specified TXG.
1738 */
1739 static int
1740 spa_vdev_remove_log(vdev_t *vd, uint64_t *txg)
1741 {
1742 metaslab_group_t *mg = vd->vdev_mg;
1743 spa_t *spa = vd->vdev_spa;
1744 int error = 0;
1745
1746 ASSERT(vd->vdev_islog);
1747 ASSERT(vd == vd->vdev_top);
1748 ASSERT(MUTEX_HELD(&spa_namespace_lock));
1749
1750 /*
1751 * Stop allocating from this vdev.
1752 */
1753 metaslab_group_passivate(mg);
1754
1755 /*
1756 * Wait for the youngest allocations and frees to sync,
1757 * and then wait for the deferral of those frees to finish.
1758 */
1759 spa_vdev_config_exit(spa, NULL,
1760 *txg + TXG_CONCURRENT_STATES + TXG_DEFER_SIZE, 0, FTAG);
1761
1762 /*
1763 * Evacuate the device. We don't hold the config lock as
1764 * writer since we need to do I/O but we do keep the
1765 * spa_namespace_lock held. Once this completes the device
1766 * should no longer have any blocks allocated on it.
1767 */
1768 ASSERT(MUTEX_HELD(&spa_namespace_lock));
1769 if (vd->vdev_stat.vs_alloc != 0)
1770 error = spa_reset_logs(spa);
1771
1772 *txg = spa_vdev_config_enter(spa);
1773
1774 if (error != 0) {
1775 metaslab_group_activate(mg);
1776 return (error);
1777 }
1778 ASSERT0(vd->vdev_stat.vs_alloc);
1779
1780 /*
1781 * The evacuation succeeded. Remove any remaining MOS metadata
1782 * associated with this vdev, and wait for these changes to sync.
1783 */
1784 vd->vdev_removing = B_TRUE;
1785
1786 vdev_dirty_leaves(vd, VDD_DTL, *txg);
1787 vdev_config_dirty(vd);
1788
1789 vdev_metaslab_fini(vd);
1790
1791 spa_history_log_internal(spa, "vdev remove", NULL,
1792 "%s vdev %llu (log) %s", spa_name(spa), vd->vdev_id,
1793 (vd->vdev_path != NULL) ? vd->vdev_path : "-");
1794
1795 /* Make sure these changes are sync'ed */
1796 spa_vdev_config_exit(spa, NULL, *txg, 0, FTAG);
1797
1798 /* Stop initializing */
1799 (void) vdev_initialize_stop_all(vd, VDEV_INITIALIZE_CANCELED);
1800
1801 *txg = spa_vdev_config_enter(spa);
1802
1803 sysevent_t *ev = spa_event_create(spa, vd, NULL,
1804 ESC_ZFS_VDEV_REMOVE_DEV);
1805 ASSERT(MUTEX_HELD(&spa_namespace_lock));
1806 ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
1807
1808 /* The top ZAP should have been destroyed by vdev_remove_empty. */
1809 ASSERT0(vd->vdev_top_zap);
1810 /* The leaf ZAP should have been destroyed by vdev_dtl_sync. */
1811 ASSERT0(vd->vdev_leaf_zap);
1812
1813 (void) vdev_label_init(vd, 0, VDEV_LABEL_REMOVE);
1814
1815 if (list_link_active(&vd->vdev_state_dirty_node))
1816 vdev_state_clean(vd);
1817 if (list_link_active(&vd->vdev_config_dirty_node))
1818 vdev_config_clean(vd);
1819
1820 ASSERT0(vd->vdev_stat.vs_alloc);
1821
1822 /*
1823 * Clean up the vdev namespace.
1824 */
1825 vdev_remove_make_hole_and_free(vd);
1826
1827 if (ev != NULL)
1828 spa_event_post(ev);
1829
1830 return (0);
1831 }
1832
1833 static int
1834 spa_vdev_remove_top_check(vdev_t *vd)
1835 {
1836 spa_t *spa = vd->vdev_spa;
1837
1838 if (vd != vd->vdev_top)
1839 return (SET_ERROR(ENOTSUP));
1840
1841 if (!spa_feature_is_enabled(spa, SPA_FEATURE_DEVICE_REMOVAL))
1842 return (SET_ERROR(ENOTSUP));
1843
1844 /* available space in the pool's normal class */
1845 uint64_t available = dsl_dir_space_available(
1846 spa->spa_dsl_pool->dp_root_dir, NULL, 0, B_TRUE);
1847
1848 metaslab_class_t *mc = vd->vdev_mg->mg_class;
1849
1850 /*
1851 * When removing a vdev from an allocation class that has
1852 * remaining vdevs, include available space from the class.
1853 */
1854 if (mc != spa_normal_class(spa) && mc->mc_groups > 1) {
1855 uint64_t class_avail = metaslab_class_get_space(mc) -
1856 metaslab_class_get_alloc(mc);
1857
1858 /* add class space, adjusted for overhead */
1859 available += (class_avail * 94) / 100;
1860 }
1861
1862 /*
1863 * There has to be enough free space to remove the
1864 * device and leave double the "slop" space (i.e. we
1865 * must leave at least 3% of the pool free, in addition to
1866 * the normal slop space).
1867 */
1868 if (available < vd->vdev_stat.vs_dspace + spa_get_slop_space(spa)) {
1869 return (SET_ERROR(ENOSPC));
1870 }
1871
1872 /*
1873 * There can not be a removal in progress.
1874 */
1875 if (spa->spa_removing_phys.sr_state == DSS_SCANNING)
1876 return (SET_ERROR(EBUSY));
1877
1878 /*
1879 * The device must have all its data.
1880 */
1881 if (!vdev_dtl_empty(vd, DTL_MISSING) ||
1882 !vdev_dtl_empty(vd, DTL_OUTAGE))
1883 return (SET_ERROR(EBUSY));
1884
1885 /*
1886 * The device must be healthy.
1887 */
1888 if (!vdev_readable(vd))
1889 return (SET_ERROR(EIO));
1890
1891 /*
1892 * All vdevs in normal class must have the same ashift.
1893 */
1894 if (spa->spa_max_ashift != spa->spa_min_ashift) {
1895 return (SET_ERROR(EINVAL));
1896 }
1897
1898 /*
1899 * All vdevs in normal class must have the same ashift
1900 * and not be raidz.
1901 */
1902 vdev_t *rvd = spa->spa_root_vdev;
1903 int num_indirect = 0;
1904 for (uint64_t id = 0; id < rvd->vdev_children; id++) {
1905 vdev_t *cvd = rvd->vdev_child[id];
1906 if (cvd->vdev_ashift != 0 && !cvd->vdev_islog)
1907 ASSERT3U(cvd->vdev_ashift, ==, spa->spa_max_ashift);
1908 if (cvd->vdev_ops == &vdev_indirect_ops)
1909 num_indirect++;
1910 if (!vdev_is_concrete(cvd))
1911 continue;
1912 if (cvd->vdev_ops == &vdev_raidz_ops)
1913 return (SET_ERROR(EINVAL));
1914 /*
1915 * Need the mirror to be mirror of leaf vdevs only
1916 */
1917 if (cvd->vdev_ops == &vdev_mirror_ops) {
1918 for (uint64_t cid = 0;
1919 cid < cvd->vdev_children; cid++) {
1920 vdev_t *tmp = cvd->vdev_child[cid];
1921 if (!tmp->vdev_ops->vdev_op_leaf)
1922 return (SET_ERROR(EINVAL));
1923 }
1924 }
1925 }
1926
1927 return (0);
1928 }
1929
1930 /*
1931 * Initiate removal of a top-level vdev, reducing the total space in the pool.
1932 * The config lock is held for the specified TXG. Once initiated,
1933 * evacuation of all allocated space (copying it to other vdevs) happens
1934 * in the background (see spa_vdev_remove_thread()), and can be canceled
1935 * (see spa_vdev_remove_cancel()). If successful, the vdev will
1936 * be transformed to an indirect vdev (see spa_vdev_remove_complete()).
1937 */
1938 static int
1939 spa_vdev_remove_top(vdev_t *vd, uint64_t *txg)
1940 {
1941 spa_t *spa = vd->vdev_spa;
1942 int error;
1943
1944 /*
1945 * Check for errors up-front, so that we don't waste time
1946 * passivating the metaslab group and clearing the ZIL if there
1947 * are errors.
1948 */
1949 error = spa_vdev_remove_top_check(vd);
1950 if (error != 0)
1951 return (error);
1952
1953 /*
1954 * Stop allocating from this vdev. Note that we must check
1955 * that this is not the only device in the pool before
1956 * passivating, otherwise we will not be able to make
1957 * progress because we can't allocate from any vdevs.
1958 * The above check for sufficient free space serves this
1959 * purpose.
1960 */
1961 metaslab_group_t *mg = vd->vdev_mg;
1962 metaslab_group_passivate(mg);
1963
1964 /*
1965 * Wait for the youngest allocations and frees to sync,
1966 * and then wait for the deferral of those frees to finish.
1967 */
1968 spa_vdev_config_exit(spa, NULL,
1969 *txg + TXG_CONCURRENT_STATES + TXG_DEFER_SIZE, 0, FTAG);
1970
1971 /*
1972 * We must ensure that no "stubby" log blocks are allocated
1973 * on the device to be removed. These blocks could be
1974 * written at any time, including while we are in the middle
1975 * of copying them.
1976 */
1977 error = spa_reset_logs(spa);
1978
1979 /*
1980 * We stop any initializing that is currently in progress but leave
1981 * the state as "active". This will allow the initializing to resume
1982 * if the removal is canceled sometime later.
1983 */
1984 vdev_initialize_stop_all(vd, VDEV_INITIALIZE_ACTIVE);
1985
1986 *txg = spa_vdev_config_enter(spa);
1987
1988 /*
1989 * Things might have changed while the config lock was dropped
1990 * (e.g. space usage). Check for errors again.
1991 */
1992 if (error == 0)
1993 error = spa_vdev_remove_top_check(vd);
1994
1995 if (error != 0) {
1996 metaslab_group_activate(mg);
1997 spa_async_request(spa, SPA_ASYNC_INITIALIZE_RESTART);
1998 return (error);
1999 }
2000
2001 vd->vdev_removing = B_TRUE;
2002
2003 vdev_dirty_leaves(vd, VDD_DTL, *txg);
2004 vdev_config_dirty(vd);
2005 dmu_tx_t *tx = dmu_tx_create_assigned(spa->spa_dsl_pool, *txg);
2006 dsl_sync_task_nowait(spa->spa_dsl_pool,
2007 vdev_remove_initiate_sync,
2008 (void *)(uintptr_t)vd->vdev_id, 0, ZFS_SPACE_CHECK_NONE, tx);
2009 dmu_tx_commit(tx);
2010
2011 return (0);
2012 }
2013
2014 /*
2015 * Remove a device from the pool.
2016 *
2017 * Removing a device from the vdev namespace requires several steps
2018 * and can take a significant amount of time. As a result we use
2019 * the spa_vdev_config_[enter/exit] functions which allow us to
2020 * grab and release the spa_config_lock while still holding the namespace
2021 * lock. During each step the configuration is synced out.
2022 */
2023 int
2024 spa_vdev_remove(spa_t *spa, uint64_t guid, boolean_t unspare)
2025 {
2026 vdev_t *vd;
2027 nvlist_t **spares, **l2cache, *nv;
2028 uint64_t txg = 0;
2029 uint_t nspares, nl2cache;
2030 int error = 0;
2031 boolean_t locked = MUTEX_HELD(&spa_namespace_lock);
2032 sysevent_t *ev = NULL;
2033
2034 ASSERT(spa_writeable(spa));
2035
2036 if (!locked)
2037 txg = spa_vdev_enter(spa);
2038
2039 ASSERT(MUTEX_HELD(&spa_namespace_lock));
2040 if (spa_feature_is_active(spa, SPA_FEATURE_POOL_CHECKPOINT)) {
2041 error = (spa_has_checkpoint(spa)) ?
2042 ZFS_ERR_CHECKPOINT_EXISTS : ZFS_ERR_DISCARDING_CHECKPOINT;
2043
2044 if (!locked)
2045 return (spa_vdev_exit(spa, NULL, txg, error));
2046
2047 return (error);
2048 }
2049
2050 vd = spa_lookup_by_guid(spa, guid, B_FALSE);
2051
2052 if (spa->spa_spares.sav_vdevs != NULL &&
2053 nvlist_lookup_nvlist_array(spa->spa_spares.sav_config,
2054 ZPOOL_CONFIG_SPARES, &spares, &nspares) == 0 &&
2055 (nv = spa_nvlist_lookup_by_guid(spares, nspares, guid)) != NULL) {
2056 /*
2057 * Only remove the hot spare if it's not currently in use
2058 * in this pool.
2059 */
2060 if (vd == NULL || unspare) {
2061 char *nvstr = fnvlist_lookup_string(nv,
2062 ZPOOL_CONFIG_PATH);
2063 spa_history_log_internal(spa, "vdev remove", NULL,
2064 "%s vdev (%s) %s", spa_name(spa),
2065 VDEV_TYPE_SPARE, nvstr);
2066 if (vd == NULL)
2067 vd = spa_lookup_by_guid(spa, guid, B_TRUE);
2068 ev = spa_event_create(spa, vd, NULL,
2069 ESC_ZFS_VDEV_REMOVE_AUX);
2070 spa_vdev_remove_aux(spa->spa_spares.sav_config,
2071 ZPOOL_CONFIG_SPARES, spares, nspares, nv);
2072 spa_load_spares(spa);
2073 spa->spa_spares.sav_sync = B_TRUE;
2074 } else {
2075 error = SET_ERROR(EBUSY);
2076 }
2077 } else if (spa->spa_l2cache.sav_vdevs != NULL &&
2078 nvlist_lookup_nvlist_array(spa->spa_l2cache.sav_config,
2079 ZPOOL_CONFIG_L2CACHE, &l2cache, &nl2cache) == 0 &&
2080 (nv = spa_nvlist_lookup_by_guid(l2cache, nl2cache, guid)) != NULL) {
2081 char *nvstr = fnvlist_lookup_string(nv, ZPOOL_CONFIG_PATH);
2082 spa_history_log_internal(spa, "vdev remove", NULL,
2083 "%s vdev (%s) %s", spa_name(spa), VDEV_TYPE_L2CACHE, nvstr);
2084 /*
2085 * Cache devices can always be removed.
2086 */
2087 vd = spa_lookup_by_guid(spa, guid, B_TRUE);
2088 ev = spa_event_create(spa, vd, NULL, ESC_ZFS_VDEV_REMOVE_AUX);
2089 spa_vdev_remove_aux(spa->spa_l2cache.sav_config,
2090 ZPOOL_CONFIG_L2CACHE, l2cache, nl2cache, nv);
2091 spa_load_l2cache(spa);
2092 spa->spa_l2cache.sav_sync = B_TRUE;
2093 } else if (vd != NULL && vd->vdev_islog) {
2094 ASSERT(!locked);
2095 error = spa_vdev_remove_log(vd, &txg);
2096 } else if (vd != NULL) {
2097 ASSERT(!locked);
2098 error = spa_vdev_remove_top(vd, &txg);
2099 } else {
2100 /*
2101 * There is no vdev of any kind with the specified guid.
2102 */
2103 error = SET_ERROR(ENOENT);
2104 }
2105
2106 if (!locked)
2107 error = spa_vdev_exit(spa, NULL, txg, error);
2108
2109 if (ev != NULL) {
2110 if (error != 0) {
2111 spa_event_discard(ev);
2112 } else {
2113 spa_event_post(ev);
2114 }
2115 }
2116
2117 return (error);
2118 }
2119
2120 int
2121 spa_removal_get_stats(spa_t *spa, pool_removal_stat_t *prs)
2122 {
2123 prs->prs_state = spa->spa_removing_phys.sr_state;
2124
2125 if (prs->prs_state == DSS_NONE)
2126 return (SET_ERROR(ENOENT));
2127
2128 prs->prs_removing_vdev = spa->spa_removing_phys.sr_removing_vdev;
2129 prs->prs_start_time = spa->spa_removing_phys.sr_start_time;
2130 prs->prs_end_time = spa->spa_removing_phys.sr_end_time;
2131 prs->prs_to_copy = spa->spa_removing_phys.sr_to_copy;
2132 prs->prs_copied = spa->spa_removing_phys.sr_copied;
2133
2134 if (spa->spa_vdev_removal != NULL) {
2135 for (int i = 0; i < TXG_SIZE; i++) {
2136 prs->prs_copied +=
2137 spa->spa_vdev_removal->svr_bytes_done[i];
2138 }
2139 }
2140
2141 prs->prs_mapping_memory = 0;
2142 uint64_t indirect_vdev_id =
2143 spa->spa_removing_phys.sr_prev_indirect_vdev;
2144 while (indirect_vdev_id != -1) {
2145 vdev_t *vd = spa->spa_root_vdev->vdev_child[indirect_vdev_id];
2146 vdev_indirect_config_t *vic = &vd->vdev_indirect_config;
2147 vdev_indirect_mapping_t *vim = vd->vdev_indirect_mapping;
2148
2149 ASSERT3P(vd->vdev_ops, ==, &vdev_indirect_ops);
2150 prs->prs_mapping_memory += vdev_indirect_mapping_size(vim);
2151 indirect_vdev_id = vic->vic_prev_indirect_vdev;
2152 }
2153
2154 return (0);
2155 }