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) 2011, 2014 by Delphix. All rights reserved.
24 * Copyright (c) 2011 Nexenta Systems, Inc. All rights reserved.
25 * Copyright 2013 Joyent, Inc. All rights reserved.
26 */
27
28 #include <sys/zfs_context.h>
29 #include <sys/fm/fs/zfs.h>
30 #include <sys/spa.h>
31 #include <sys/txg.h>
32 #include <sys/spa_impl.h>
33 #include <sys/vdev_impl.h>
34 #include <sys/zio_impl.h>
35 #include <sys/zio_compress.h>
36 #include <sys/zio_checksum.h>
37 #include <sys/dmu_objset.h>
38 #include <sys/arc.h>
39 #include <sys/ddt.h>
40 #include <sys/zfs_zone.h>
41 #include <sys/zfeature.h>
42
43 /*
44 * ==========================================================================
45 * I/O type descriptions
46 * ==========================================================================
47 */
48 const char *zio_type_name[ZIO_TYPES] = {
49 "zio_null", "zio_read", "zio_write", "zio_free", "zio_claim",
50 "zio_ioctl"
51 };
52
53 /*
54 * ==========================================================================
55 * I/O kmem caches
56 * ==========================================================================
57 */
58 kmem_cache_t *zio_cache;
59 kmem_cache_t *zio_link_cache;
60 kmem_cache_t *zio_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
61 kmem_cache_t *zio_data_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
62
63 #ifdef _KERNEL
64 extern vmem_t *zio_alloc_arena;
65 #endif
66 extern int zfs_mg_alloc_failures;
67
68 /*
69 * The following actions directly effect the spa's sync-to-convergence logic.
70 * The values below define the sync pass when we start performing the action.
71 * Care should be taken when changing these values as they directly impact
72 * spa_sync() performance. Tuning these values may introduce subtle performance
73 * pathologies and should only be done in the context of performance analysis.
74 * These tunables will eventually be removed and replaced with #defines once
75 * enough analysis has been done to determine optimal values.
76 *
77 * The 'zfs_sync_pass_deferred_free' pass must be greater than 1 to ensure that
78 * regular blocks are not deferred.
79 */
80 int zfs_sync_pass_deferred_free = 2; /* defer frees starting in this pass */
81 int zfs_sync_pass_dont_compress = 5; /* don't compress starting in this pass */
82 int zfs_sync_pass_rewrite = 2; /* rewrite new bps starting in this pass */
83
84 /*
85 * An allocating zio is one that either currently has the DVA allocate
86 * stage set or will have it later in its lifetime.
87 */
88 #define IO_IS_ALLOCATING(zio) ((zio)->io_orig_pipeline & ZIO_STAGE_DVA_ALLOCATE)
89
90 boolean_t zio_requeue_io_start_cut_in_line = B_TRUE;
91
92 #ifdef ZFS_DEBUG
93 int zio_buf_debug_limit = 16384;
94 #else
95 int zio_buf_debug_limit = 0;
96 #endif
97
98 void
99 zio_init(void)
100 {
101 size_t c;
102 vmem_t *data_alloc_arena = NULL;
103
104 #ifdef _KERNEL
105 data_alloc_arena = zio_alloc_arena;
106 #endif
107 zio_cache = kmem_cache_create("zio_cache",
108 sizeof (zio_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
109 zio_link_cache = kmem_cache_create("zio_link_cache",
110 sizeof (zio_link_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
111
112 /*
113 * For small buffers, we want a cache for each multiple of
114 * SPA_MINBLOCKSIZE. For medium-size buffers, we want a cache
115 * for each quarter-power of 2. For large buffers, we want
116 * a cache for each multiple of PAGESIZE.
117 */
118 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) {
119 size_t size = (c + 1) << SPA_MINBLOCKSHIFT;
120 size_t p2 = size;
121 size_t align = 0;
122 size_t cflags = (size > zio_buf_debug_limit) ? KMC_NODEBUG : 0;
123
124 while (p2 & (p2 - 1))
125 p2 &= p2 - 1;
126
127 #ifndef _KERNEL
128 /*
129 * If we are using watchpoints, put each buffer on its own page,
130 * to eliminate the performance overhead of trapping to the
131 * kernel when modifying a non-watched buffer that shares the
132 * page with a watched buffer.
133 */
134 if (arc_watch && !IS_P2ALIGNED(size, PAGESIZE))
135 continue;
136 #endif
137 if (size <= 4 * SPA_MINBLOCKSIZE) {
138 align = SPA_MINBLOCKSIZE;
139 } else if (IS_P2ALIGNED(size, PAGESIZE)) {
140 align = PAGESIZE;
141 } else if (IS_P2ALIGNED(size, p2 >> 2)) {
142 align = p2 >> 2;
143 }
144
145 if (align != 0) {
146 char name[36];
147 (void) sprintf(name, "zio_buf_%lu", (ulong_t)size);
148 zio_buf_cache[c] = kmem_cache_create(name, size,
149 align, NULL, NULL, NULL, NULL, NULL, cflags);
150
151 /*
152 * Since zio_data bufs do not appear in crash dumps, we
153 * pass KMC_NOTOUCH so that no allocator metadata is
154 * stored with the buffers.
155 */
156 (void) sprintf(name, "zio_data_buf_%lu", (ulong_t)size);
157 zio_data_buf_cache[c] = kmem_cache_create(name, size,
158 align, NULL, NULL, NULL, NULL, data_alloc_arena,
159 cflags | KMC_NOTOUCH);
160 }
161 }
162
163 while (--c != 0) {
164 ASSERT(zio_buf_cache[c] != NULL);
165 if (zio_buf_cache[c - 1] == NULL)
166 zio_buf_cache[c - 1] = zio_buf_cache[c];
167
168 ASSERT(zio_data_buf_cache[c] != NULL);
169 if (zio_data_buf_cache[c - 1] == NULL)
170 zio_data_buf_cache[c - 1] = zio_data_buf_cache[c];
171 }
172
173 /*
174 * The zio write taskqs have 1 thread per cpu, allow 1/2 of the taskqs
175 * to fail 3 times per txg or 8 failures, whichever is greater.
176 */
177 if (zfs_mg_alloc_failures == 0)
178 zfs_mg_alloc_failures = MAX((3 * max_ncpus / 2), 8);
179
180 zio_inject_init();
181 }
182
183 void
184 zio_fini(void)
185 {
186 size_t c;
187 kmem_cache_t *last_cache = NULL;
188 kmem_cache_t *last_data_cache = NULL;
189
190 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) {
191 if (zio_buf_cache[c] != last_cache) {
192 last_cache = zio_buf_cache[c];
193 kmem_cache_destroy(zio_buf_cache[c]);
194 }
195 zio_buf_cache[c] = NULL;
196
197 if (zio_data_buf_cache[c] != last_data_cache) {
198 last_data_cache = zio_data_buf_cache[c];
199 kmem_cache_destroy(zio_data_buf_cache[c]);
200 }
201 zio_data_buf_cache[c] = NULL;
202 }
203
204 kmem_cache_destroy(zio_link_cache);
205 kmem_cache_destroy(zio_cache);
206
207 zio_inject_fini();
208 }
209
210 /*
211 * ==========================================================================
212 * Allocate and free I/O buffers
213 * ==========================================================================
214 */
215
216 /*
217 * Use zio_buf_alloc to allocate ZFS metadata. This data will appear in a
218 * crashdump if the kernel panics, so use it judiciously. Obviously, it's
219 * useful to inspect ZFS metadata, but if possible, we should avoid keeping
220 * excess / transient data in-core during a crashdump.
221 */
222 void *
223 zio_buf_alloc(size_t size)
224 {
225 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
226
227 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
228
229 return (kmem_cache_alloc(zio_buf_cache[c], KM_PUSHPAGE));
230 }
231
232 /*
233 * Use zio_data_buf_alloc to allocate data. The data will not appear in a
234 * crashdump if the kernel panics. This exists so that we will limit the amount
235 * of ZFS data that shows up in a kernel crashdump. (Thus reducing the amount
236 * of kernel heap dumped to disk when the kernel panics)
237 */
238 void *
239 zio_data_buf_alloc(size_t size)
240 {
241 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
242
243 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
244
245 return (kmem_cache_alloc(zio_data_buf_cache[c], KM_PUSHPAGE));
246 }
247
248 void
249 zio_buf_free(void *buf, size_t size)
250 {
251 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
252
253 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
254
255 kmem_cache_free(zio_buf_cache[c], buf);
256 }
257
258 void
259 zio_data_buf_free(void *buf, size_t size)
260 {
261 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
262
263 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
264
265 kmem_cache_free(zio_data_buf_cache[c], buf);
266 }
267
268 /*
269 * ==========================================================================
270 * Push and pop I/O transform buffers
271 * ==========================================================================
272 */
273 static void
274 zio_push_transform(zio_t *zio, void *data, uint64_t size, uint64_t bufsize,
275 zio_transform_func_t *transform)
276 {
277 zio_transform_t *zt = kmem_alloc(sizeof (zio_transform_t), KM_SLEEP);
278
279 zt->zt_orig_data = zio->io_data;
280 zt->zt_orig_size = zio->io_size;
281 zt->zt_bufsize = bufsize;
282 zt->zt_transform = transform;
283
284 zt->zt_next = zio->io_transform_stack;
285 zio->io_transform_stack = zt;
286
287 zio->io_data = data;
288 zio->io_size = size;
289 }
290
291 static void
292 zio_pop_transforms(zio_t *zio)
293 {
294 zio_transform_t *zt;
295
296 while ((zt = zio->io_transform_stack) != NULL) {
297 if (zt->zt_transform != NULL)
298 zt->zt_transform(zio,
299 zt->zt_orig_data, zt->zt_orig_size);
300
301 if (zt->zt_bufsize != 0)
302 zio_buf_free(zio->io_data, zt->zt_bufsize);
303
304 zio->io_data = zt->zt_orig_data;
305 zio->io_size = zt->zt_orig_size;
306 zio->io_transform_stack = zt->zt_next;
307
308 kmem_free(zt, sizeof (zio_transform_t));
309 }
310 }
311
312 /*
313 * ==========================================================================
314 * I/O transform callbacks for subblocks and decompression
315 * ==========================================================================
316 */
317 static void
318 zio_subblock(zio_t *zio, void *data, uint64_t size)
319 {
320 ASSERT(zio->io_size > size);
321
322 if (zio->io_type == ZIO_TYPE_READ)
323 bcopy(zio->io_data, data, size);
324 }
325
326 static void
327 zio_decompress(zio_t *zio, void *data, uint64_t size)
328 {
329 if (zio->io_error == 0 &&
330 zio_decompress_data(BP_GET_COMPRESS(zio->io_bp),
331 zio->io_data, data, zio->io_size, size) != 0)
332 zio->io_error = SET_ERROR(EIO);
333 }
334
335 /*
336 * ==========================================================================
337 * I/O parent/child relationships and pipeline interlocks
338 * ==========================================================================
339 */
340 /*
341 * NOTE - Callers to zio_walk_parents() and zio_walk_children must
342 * continue calling these functions until they return NULL.
343 * Otherwise, the next caller will pick up the list walk in
344 * some indeterminate state. (Otherwise every caller would
345 * have to pass in a cookie to keep the state represented by
346 * io_walk_link, which gets annoying.)
347 */
348 zio_t *
349 zio_walk_parents(zio_t *cio)
350 {
351 zio_link_t *zl = cio->io_walk_link;
352 list_t *pl = &cio->io_parent_list;
353
354 zl = (zl == NULL) ? list_head(pl) : list_next(pl, zl);
355 cio->io_walk_link = zl;
356
357 if (zl == NULL)
358 return (NULL);
359
360 ASSERT(zl->zl_child == cio);
361 return (zl->zl_parent);
362 }
363
364 zio_t *
365 zio_walk_children(zio_t *pio)
366 {
367 zio_link_t *zl = pio->io_walk_link;
368 list_t *cl = &pio->io_child_list;
369
370 zl = (zl == NULL) ? list_head(cl) : list_next(cl, zl);
371 pio->io_walk_link = zl;
372
373 if (zl == NULL)
374 return (NULL);
375
376 ASSERT(zl->zl_parent == pio);
377 return (zl->zl_child);
378 }
379
380 zio_t *
381 zio_unique_parent(zio_t *cio)
382 {
383 zio_t *pio = zio_walk_parents(cio);
384
385 VERIFY(zio_walk_parents(cio) == NULL);
386 return (pio);
387 }
388
389 void
390 zio_add_child(zio_t *pio, zio_t *cio)
391 {
392 zio_link_t *zl = kmem_cache_alloc(zio_link_cache, KM_SLEEP);
393
394 /*
395 * Logical I/Os can have logical, gang, or vdev children.
396 * Gang I/Os can have gang or vdev children.
397 * Vdev I/Os can only have vdev children.
398 * The following ASSERT captures all of these constraints.
399 */
400 ASSERT(cio->io_child_type <= pio->io_child_type);
401
402 zl->zl_parent = pio;
403 zl->zl_child = cio;
404
405 mutex_enter(&cio->io_lock);
406 mutex_enter(&pio->io_lock);
407
408 ASSERT(pio->io_state[ZIO_WAIT_DONE] == 0);
409
410 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
411 pio->io_children[cio->io_child_type][w] += !cio->io_state[w];
412
413 list_insert_head(&pio->io_child_list, zl);
414 list_insert_head(&cio->io_parent_list, zl);
415
416 pio->io_child_count++;
417 cio->io_parent_count++;
418
419 mutex_exit(&pio->io_lock);
420 mutex_exit(&cio->io_lock);
421 }
422
423 static void
424 zio_remove_child(zio_t *pio, zio_t *cio, zio_link_t *zl)
425 {
426 ASSERT(zl->zl_parent == pio);
427 ASSERT(zl->zl_child == cio);
428
429 mutex_enter(&cio->io_lock);
430 mutex_enter(&pio->io_lock);
431
432 list_remove(&pio->io_child_list, zl);
433 list_remove(&cio->io_parent_list, zl);
434
435 pio->io_child_count--;
436 cio->io_parent_count--;
437
438 mutex_exit(&pio->io_lock);
439 mutex_exit(&cio->io_lock);
440
441 kmem_cache_free(zio_link_cache, zl);
442 }
443
444 static boolean_t
445 zio_wait_for_children(zio_t *zio, enum zio_child child, enum zio_wait_type wait)
446 {
447 uint64_t *countp = &zio->io_children[child][wait];
448 boolean_t waiting = B_FALSE;
449
450 mutex_enter(&zio->io_lock);
451 ASSERT(zio->io_stall == NULL);
452 if (*countp != 0) {
453 zio->io_stage >>= 1;
454 zio->io_stall = countp;
455 waiting = B_TRUE;
456 }
457 mutex_exit(&zio->io_lock);
458
459 return (waiting);
460 }
461
462 static void
463 zio_notify_parent(zio_t *pio, zio_t *zio, enum zio_wait_type wait)
464 {
465 uint64_t *countp = &pio->io_children[zio->io_child_type][wait];
466 int *errorp = &pio->io_child_error[zio->io_child_type];
467
468 mutex_enter(&pio->io_lock);
469 if (zio->io_error && !(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE))
470 *errorp = zio_worst_error(*errorp, zio->io_error);
471 pio->io_reexecute |= zio->io_reexecute;
472 ASSERT3U(*countp, >, 0);
473
474 (*countp)--;
475
476 if (*countp == 0 && pio->io_stall == countp) {
477 pio->io_stall = NULL;
478 mutex_exit(&pio->io_lock);
479 zio_execute(pio);
480 } else {
481 mutex_exit(&pio->io_lock);
482 }
483 }
484
485 static void
486 zio_inherit_child_errors(zio_t *zio, enum zio_child c)
487 {
488 if (zio->io_child_error[c] != 0 && zio->io_error == 0)
489 zio->io_error = zio->io_child_error[c];
490 }
491
492 /*
493 * ==========================================================================
494 * Create the various types of I/O (read, write, free, etc)
495 * ==========================================================================
496 */
497 static zio_t *
498 zio_create(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
499 void *data, uint64_t size, zio_done_func_t *done, void *private,
500 zio_type_t type, zio_priority_t priority, enum zio_flag flags,
501 vdev_t *vd, uint64_t offset, const zbookmark_t *zb,
502 enum zio_stage stage, enum zio_stage pipeline)
503 {
504 zio_t *zio;
505
506 ASSERT3U(size, <=, SPA_MAXBLOCKSIZE);
507 ASSERT(P2PHASE(size, SPA_MINBLOCKSIZE) == 0);
508 ASSERT(P2PHASE(offset, SPA_MINBLOCKSIZE) == 0);
509
510 ASSERT(!vd || spa_config_held(spa, SCL_STATE_ALL, RW_READER));
511 ASSERT(!bp || !(flags & ZIO_FLAG_CONFIG_WRITER));
512 ASSERT(vd || stage == ZIO_STAGE_OPEN);
513
514 zio = kmem_cache_alloc(zio_cache, KM_SLEEP);
515 bzero(zio, sizeof (zio_t));
516
517 mutex_init(&zio->io_lock, NULL, MUTEX_DEFAULT, NULL);
518 cv_init(&zio->io_cv, NULL, CV_DEFAULT, NULL);
519
520 list_create(&zio->io_parent_list, sizeof (zio_link_t),
521 offsetof(zio_link_t, zl_parent_node));
522 list_create(&zio->io_child_list, sizeof (zio_link_t),
523 offsetof(zio_link_t, zl_child_node));
524
525 if (vd != NULL)
526 zio->io_child_type = ZIO_CHILD_VDEV;
527 else if (flags & ZIO_FLAG_GANG_CHILD)
528 zio->io_child_type = ZIO_CHILD_GANG;
529 else if (flags & ZIO_FLAG_DDT_CHILD)
530 zio->io_child_type = ZIO_CHILD_DDT;
531 else
532 zio->io_child_type = ZIO_CHILD_LOGICAL;
533
534 if (bp != NULL) {
535 zio->io_bp = (blkptr_t *)bp;
536 zio->io_bp_copy = *bp;
537 zio->io_bp_orig = *bp;
538 if (type != ZIO_TYPE_WRITE ||
539 zio->io_child_type == ZIO_CHILD_DDT)
540 zio->io_bp = &zio->io_bp_copy; /* so caller can free */
541 if (zio->io_child_type == ZIO_CHILD_LOGICAL)
542 zio->io_logical = zio;
543 if (zio->io_child_type > ZIO_CHILD_GANG && BP_IS_GANG(bp))
544 pipeline |= ZIO_GANG_STAGES;
545 }
546
547 zio->io_spa = spa;
548 zio->io_txg = txg;
549 zio->io_done = done;
550 zio->io_private = private;
551 zio->io_type = type;
552 zio->io_priority = priority;
553 zio->io_vd = vd;
554 zio->io_offset = offset;
555 zio->io_orig_data = zio->io_data = data;
556 zio->io_orig_size = zio->io_size = size;
557 zio->io_orig_flags = zio->io_flags = flags;
558 zio->io_orig_stage = zio->io_stage = stage;
559 zio->io_orig_pipeline = zio->io_pipeline = pipeline;
560
561 zio->io_state[ZIO_WAIT_READY] = (stage >= ZIO_STAGE_READY);
562 zio->io_state[ZIO_WAIT_DONE] = (stage >= ZIO_STAGE_DONE);
563
564 if (zb != NULL)
565 zio->io_bookmark = *zb;
566
567 if (pio != NULL) {
568 zio->io_zoneid = pio->io_zoneid;
569 if (zio->io_logical == NULL)
570 zio->io_logical = pio->io_logical;
571 if (zio->io_child_type == ZIO_CHILD_GANG)
572 zio->io_gang_leader = pio->io_gang_leader;
573 zio_add_child(pio, zio);
574 } else {
575 zfs_zone_zio_init(zio);
576 }
577
578 return (zio);
579 }
580
581 static void
582 zio_destroy(zio_t *zio)
583 {
584 list_destroy(&zio->io_parent_list);
585 list_destroy(&zio->io_child_list);
586 mutex_destroy(&zio->io_lock);
587 cv_destroy(&zio->io_cv);
588 kmem_cache_free(zio_cache, zio);
589 }
590
591 zio_t *
592 zio_null(zio_t *pio, spa_t *spa, vdev_t *vd, zio_done_func_t *done,
593 void *private, enum zio_flag flags)
594 {
595 zio_t *zio;
596
597 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private,
598 ZIO_TYPE_NULL, ZIO_PRIORITY_NOW, flags, vd, 0, NULL,
599 ZIO_STAGE_OPEN, ZIO_INTERLOCK_PIPELINE);
600
601 return (zio);
602 }
603
604 zio_t *
605 zio_root(spa_t *spa, zio_done_func_t *done, void *private, enum zio_flag flags)
606 {
607 return (zio_null(NULL, spa, NULL, done, private, flags));
608 }
609
610 zio_t *
611 zio_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
612 void *data, uint64_t size, zio_done_func_t *done, void *private,
613 zio_priority_t priority, enum zio_flag flags, const zbookmark_t *zb)
614 {
615 zio_t *zio;
616
617 zio = zio_create(pio, spa, BP_PHYSICAL_BIRTH(bp), bp,
618 data, size, done, private,
619 ZIO_TYPE_READ, priority, flags, NULL, 0, zb,
620 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ?
621 ZIO_DDT_CHILD_READ_PIPELINE : ZIO_READ_PIPELINE);
622
623 return (zio);
624 }
625
626 zio_t *
627 zio_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
628 void *data, uint64_t size, const zio_prop_t *zp,
629 zio_done_func_t *ready, zio_done_func_t *physdone, zio_done_func_t *done,
630 void *private,
631 zio_priority_t priority, enum zio_flag flags, const zbookmark_t *zb)
632 {
633 zio_t *zio;
634
635 ASSERT(zp->zp_checksum >= ZIO_CHECKSUM_OFF &&
636 zp->zp_checksum < ZIO_CHECKSUM_FUNCTIONS &&
637 zp->zp_compress >= ZIO_COMPRESS_OFF &&
638 zp->zp_compress < ZIO_COMPRESS_FUNCTIONS &&
639 DMU_OT_IS_VALID(zp->zp_type) &&
640 zp->zp_level < 32 &&
641 zp->zp_copies > 0 &&
642 zp->zp_copies <= spa_max_replication(spa));
643
644 zio = zio_create(pio, spa, txg, bp, data, size, done, private,
645 ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb,
646 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ?
647 ZIO_DDT_CHILD_WRITE_PIPELINE : ZIO_WRITE_PIPELINE);
648
649 zio->io_ready = ready;
650 zio->io_physdone = physdone;
651 zio->io_prop = *zp;
652
653 return (zio);
654 }
655
656 zio_t *
657 zio_rewrite(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, void *data,
658 uint64_t size, zio_done_func_t *done, void *private,
659 zio_priority_t priority, enum zio_flag flags, zbookmark_t *zb)
660 {
661 zio_t *zio;
662
663 zio = zio_create(pio, spa, txg, bp, data, size, done, private,
664 ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb,
665 ZIO_STAGE_OPEN, ZIO_REWRITE_PIPELINE);
666
667 return (zio);
668 }
669
670 void
671 zio_write_override(zio_t *zio, blkptr_t *bp, int copies, boolean_t nopwrite)
672 {
673 ASSERT(zio->io_type == ZIO_TYPE_WRITE);
674 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
675 ASSERT(zio->io_stage == ZIO_STAGE_OPEN);
676 ASSERT(zio->io_txg == spa_syncing_txg(zio->io_spa));
677
678 /*
679 * We must reset the io_prop to match the values that existed
680 * when the bp was first written by dmu_sync() keeping in mind
681 * that nopwrite and dedup are mutually exclusive.
682 */
683 zio->io_prop.zp_dedup = nopwrite ? B_FALSE : zio->io_prop.zp_dedup;
684 zio->io_prop.zp_nopwrite = nopwrite;
685 zio->io_prop.zp_copies = copies;
686 zio->io_bp_override = bp;
687 }
688
689 void
690 zio_free(spa_t *spa, uint64_t txg, const blkptr_t *bp)
691 {
692 metaslab_check_free(spa, bp);
693
694 /*
695 * Frees that are for the currently-syncing txg, are not going to be
696 * deferred, and which will not need to do a read (i.e. not GANG or
697 * DEDUP), can be processed immediately. Otherwise, put them on the
698 * in-memory list for later processing.
699 */
700 if (BP_IS_GANG(bp) || BP_GET_DEDUP(bp) ||
701 txg != spa->spa_syncing_txg ||
702 spa_sync_pass(spa) >= zfs_sync_pass_deferred_free) {
703 bplist_append(&spa->spa_free_bplist[txg & TXG_MASK], bp);
704 } else {
705 VERIFY0(zio_wait(zio_free_sync(NULL, spa, txg, bp, 0)));
706 }
707 }
708
709 zio_t *
710 zio_free_sync(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
711 enum zio_flag flags)
712 {
713 zio_t *zio;
714 enum zio_stage stage = ZIO_FREE_PIPELINE;
715
716 dprintf_bp(bp, "freeing in txg %llu, pass %u",
717 (longlong_t)txg, spa->spa_sync_pass);
718
719 ASSERT(!BP_IS_HOLE(bp));
720 ASSERT(spa_syncing_txg(spa) == txg);
721 ASSERT(spa_sync_pass(spa) < zfs_sync_pass_deferred_free);
722
723 metaslab_check_free(spa, bp);
724 arc_freed(spa, bp);
725
726 /*
727 * GANG and DEDUP blocks can induce a read (for the gang block header,
728 * or the DDT), so issue them asynchronously so that this thread is
729 * not tied up.
730 */
731 if (BP_IS_GANG(bp) || BP_GET_DEDUP(bp))
732 stage |= ZIO_STAGE_ISSUE_ASYNC;
733
734 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp),
735 NULL, NULL, ZIO_TYPE_FREE, ZIO_PRIORITY_NOW, flags,
736 NULL, 0, NULL, ZIO_STAGE_OPEN, stage);
737
738
739 return (zio);
740 }
741
742 zio_t *
743 zio_claim(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
744 zio_done_func_t *done, void *private, enum zio_flag flags)
745 {
746 zio_t *zio;
747
748 /*
749 * A claim is an allocation of a specific block. Claims are needed
750 * to support immediate writes in the intent log. The issue is that
751 * immediate writes contain committed data, but in a txg that was
752 * *not* committed. Upon opening the pool after an unclean shutdown,
753 * the intent log claims all blocks that contain immediate write data
754 * so that the SPA knows they're in use.
755 *
756 * All claims *must* be resolved in the first txg -- before the SPA
757 * starts allocating blocks -- so that nothing is allocated twice.
758 * If txg == 0 we just verify that the block is claimable.
759 */
760 ASSERT3U(spa->spa_uberblock.ub_rootbp.blk_birth, <, spa_first_txg(spa));
761 ASSERT(txg == spa_first_txg(spa) || txg == 0);
762 ASSERT(!BP_GET_DEDUP(bp) || !spa_writeable(spa)); /* zdb(1M) */
763
764 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp),
765 done, private, ZIO_TYPE_CLAIM, ZIO_PRIORITY_NOW, flags,
766 NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_CLAIM_PIPELINE);
767
768 return (zio);
769 }
770
771 zio_t *
772 zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd,
773 zio_done_func_t *done, void *private, enum zio_flag flags)
774 {
775 zio_t *zio;
776 int c;
777
778 if (vd->vdev_children == 0) {
779 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private,
780 ZIO_TYPE_IOCTL, ZIO_PRIORITY_NOW, flags, vd, 0, NULL,
781 ZIO_STAGE_OPEN, ZIO_IOCTL_PIPELINE);
782
783 zio->io_cmd = cmd;
784 } else {
785 zio = zio_null(pio, spa, NULL, NULL, NULL, flags);
786
787 for (c = 0; c < vd->vdev_children; c++)
788 zio_nowait(zio_ioctl(zio, spa, vd->vdev_child[c], cmd,
789 done, private, flags));
790 }
791
792 return (zio);
793 }
794
795 zio_t *
796 zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size,
797 void *data, int checksum, zio_done_func_t *done, void *private,
798 zio_priority_t priority, enum zio_flag flags, boolean_t labels)
799 {
800 zio_t *zio;
801
802 ASSERT(vd->vdev_children == 0);
803 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE ||
804 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE);
805 ASSERT3U(offset + size, <=, vd->vdev_psize);
806
807 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private,
808 ZIO_TYPE_READ, priority, flags, vd, offset, NULL,
809 ZIO_STAGE_OPEN, ZIO_READ_PHYS_PIPELINE);
810
811 zio->io_prop.zp_checksum = checksum;
812
813 return (zio);
814 }
815
816 zio_t *
817 zio_write_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size,
818 void *data, int checksum, zio_done_func_t *done, void *private,
819 zio_priority_t priority, enum zio_flag flags, boolean_t labels)
820 {
821 zio_t *zio;
822
823 ASSERT(vd->vdev_children == 0);
824 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE ||
825 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE);
826 ASSERT3U(offset + size, <=, vd->vdev_psize);
827
828 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private,
829 ZIO_TYPE_WRITE, priority, flags, vd, offset, NULL,
830 ZIO_STAGE_OPEN, ZIO_WRITE_PHYS_PIPELINE);
831
832 zio->io_prop.zp_checksum = checksum;
833
834 if (zio_checksum_table[checksum].ci_eck) {
835 /*
836 * zec checksums are necessarily destructive -- they modify
837 * the end of the write buffer to hold the verifier/checksum.
838 * Therefore, we must make a local copy in case the data is
839 * being written to multiple places in parallel.
840 */
841 void *wbuf = zio_buf_alloc(size);
842 bcopy(data, wbuf, size);
843 zio_push_transform(zio, wbuf, size, size, NULL);
844 }
845
846 return (zio);
847 }
848
849 /*
850 * Create a child I/O to do some work for us.
851 */
852 zio_t *
853 zio_vdev_child_io(zio_t *pio, blkptr_t *bp, vdev_t *vd, uint64_t offset,
854 void *data, uint64_t size, int type, zio_priority_t priority,
855 enum zio_flag flags, zio_done_func_t *done, void *private)
856 {
857 enum zio_stage pipeline = ZIO_VDEV_CHILD_PIPELINE;
858 zio_t *zio;
859
860 ASSERT(vd->vdev_parent ==
861 (pio->io_vd ? pio->io_vd : pio->io_spa->spa_root_vdev));
862
863 if (type == ZIO_TYPE_READ && bp != NULL) {
864 /*
865 * If we have the bp, then the child should perform the
866 * checksum and the parent need not. This pushes error
867 * detection as close to the leaves as possible and
868 * eliminates redundant checksums in the interior nodes.
869 */
870 pipeline |= ZIO_STAGE_CHECKSUM_VERIFY;
871 pio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY;
872 }
873
874 if (vd->vdev_children == 0)
875 offset += VDEV_LABEL_START_SIZE;
876
877 flags |= ZIO_VDEV_CHILD_FLAGS(pio) | ZIO_FLAG_DONT_PROPAGATE;
878
879 /*
880 * If we've decided to do a repair, the write is not speculative --
881 * even if the original read was.
882 */
883 if (flags & ZIO_FLAG_IO_REPAIR)
884 flags &= ~ZIO_FLAG_SPECULATIVE;
885
886 zio = zio_create(pio, pio->io_spa, pio->io_txg, bp, data, size,
887 done, private, type, priority, flags, vd, offset, &pio->io_bookmark,
888 ZIO_STAGE_VDEV_IO_START >> 1, pipeline);
889
890 zio->io_physdone = pio->io_physdone;
891 if (vd->vdev_ops->vdev_op_leaf && zio->io_logical != NULL)
892 zio->io_logical->io_phys_children++;
893
894 return (zio);
895 }
896
897 zio_t *
898 zio_vdev_delegated_io(vdev_t *vd, uint64_t offset, void *data, uint64_t size,
899 int type, zio_priority_t priority, enum zio_flag flags,
900 zio_done_func_t *done, void *private)
901 {
902 zio_t *zio;
903
904 ASSERT(vd->vdev_ops->vdev_op_leaf);
905
906 zio = zio_create(NULL, vd->vdev_spa, 0, NULL,
907 data, size, done, private, type, priority,
908 flags | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_RETRY | ZIO_FLAG_DELEGATED,
909 vd, offset, NULL,
910 ZIO_STAGE_VDEV_IO_START >> 1, ZIO_VDEV_CHILD_PIPELINE);
911
912 return (zio);
913 }
914
915 void
916 zio_flush(zio_t *zio, vdev_t *vd)
917 {
918 zio_nowait(zio_ioctl(zio, zio->io_spa, vd, DKIOCFLUSHWRITECACHE,
919 NULL, NULL,
920 ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY));
921 }
922
923 void
924 zio_shrink(zio_t *zio, uint64_t size)
925 {
926 ASSERT(zio->io_executor == NULL);
927 ASSERT(zio->io_orig_size == zio->io_size);
928 ASSERT(size <= zio->io_size);
929
930 /*
931 * We don't shrink for raidz because of problems with the
932 * reconstruction when reading back less than the block size.
933 * Note, BP_IS_RAIDZ() assumes no compression.
934 */
935 ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF);
936 if (!BP_IS_RAIDZ(zio->io_bp))
937 zio->io_orig_size = zio->io_size = size;
938 }
939
940 /*
941 * ==========================================================================
942 * Prepare to read and write logical blocks
943 * ==========================================================================
944 */
945
946 static int
947 zio_read_bp_init(zio_t *zio)
948 {
949 blkptr_t *bp = zio->io_bp;
950
951 if (BP_GET_COMPRESS(bp) != ZIO_COMPRESS_OFF &&
952 zio->io_child_type == ZIO_CHILD_LOGICAL &&
953 !(zio->io_flags & ZIO_FLAG_RAW)) {
954 uint64_t psize = BP_GET_PSIZE(bp);
955 void *cbuf = zio_buf_alloc(psize);
956
957 zio_push_transform(zio, cbuf, psize, psize, zio_decompress);
958 }
959
960 if (!DMU_OT_IS_METADATA(BP_GET_TYPE(bp)) && BP_GET_LEVEL(bp) == 0)
961 zio->io_flags |= ZIO_FLAG_DONT_CACHE;
962
963 if (BP_GET_TYPE(bp) == DMU_OT_DDT_ZAP)
964 zio->io_flags |= ZIO_FLAG_DONT_CACHE;
965
966 if (BP_GET_DEDUP(bp) && zio->io_child_type == ZIO_CHILD_LOGICAL)
967 zio->io_pipeline = ZIO_DDT_READ_PIPELINE;
968
969 return (ZIO_PIPELINE_CONTINUE);
970 }
971
972 static int
973 zio_write_bp_init(zio_t *zio)
974 {
975 spa_t *spa = zio->io_spa;
976 zio_prop_t *zp = &zio->io_prop;
977 enum zio_compress compress = zp->zp_compress;
978 blkptr_t *bp = zio->io_bp;
979 uint64_t lsize = zio->io_size;
980 uint64_t psize = lsize;
981 int pass = 1;
982
983 /*
984 * If our children haven't all reached the ready stage,
985 * wait for them and then repeat this pipeline stage.
986 */
987 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) ||
988 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_READY))
989 return (ZIO_PIPELINE_STOP);
990
991 if (!IO_IS_ALLOCATING(zio))
992 return (ZIO_PIPELINE_CONTINUE);
993
994 ASSERT(zio->io_child_type != ZIO_CHILD_DDT);
995
996 if (zio->io_bp_override) {
997 ASSERT(bp->blk_birth != zio->io_txg);
998 ASSERT(BP_GET_DEDUP(zio->io_bp_override) == 0);
999
1000 *bp = *zio->io_bp_override;
1001 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1002
1003 /*
1004 * If we've been overridden and nopwrite is set then
1005 * set the flag accordingly to indicate that a nopwrite
1006 * has already occurred.
1007 */
1008 if (!BP_IS_HOLE(bp) && zp->zp_nopwrite) {
1009 ASSERT(!zp->zp_dedup);
1010 zio->io_flags |= ZIO_FLAG_NOPWRITE;
1011 return (ZIO_PIPELINE_CONTINUE);
1012 }
1013
1014 ASSERT(!zp->zp_nopwrite);
1015
1016 if (BP_IS_HOLE(bp) || !zp->zp_dedup)
1017 return (ZIO_PIPELINE_CONTINUE);
1018
1019 ASSERT(zio_checksum_table[zp->zp_checksum].ci_dedup ||
1020 zp->zp_dedup_verify);
1021
1022 if (BP_GET_CHECKSUM(bp) == zp->zp_checksum) {
1023 BP_SET_DEDUP(bp, 1);
1024 zio->io_pipeline |= ZIO_STAGE_DDT_WRITE;
1025 return (ZIO_PIPELINE_CONTINUE);
1026 }
1027 zio->io_bp_override = NULL;
1028 BP_ZERO(bp);
1029 }
1030
1031 if (!BP_IS_HOLE(bp) && bp->blk_birth == zio->io_txg) {
1032 /*
1033 * We're rewriting an existing block, which means we're
1034 * working on behalf of spa_sync(). For spa_sync() to
1035 * converge, it must eventually be the case that we don't
1036 * have to allocate new blocks. But compression changes
1037 * the blocksize, which forces a reallocate, and makes
1038 * convergence take longer. Therefore, after the first
1039 * few passes, stop compressing to ensure convergence.
1040 */
1041 pass = spa_sync_pass(spa);
1042
1043 ASSERT(zio->io_txg == spa_syncing_txg(spa));
1044 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1045 ASSERT(!BP_GET_DEDUP(bp));
1046
1047 if (pass >= zfs_sync_pass_dont_compress)
1048 compress = ZIO_COMPRESS_OFF;
1049
1050 /* Make sure someone doesn't change their mind on overwrites */
1051 ASSERT(MIN(zp->zp_copies + BP_IS_GANG(bp),
1052 spa_max_replication(spa)) == BP_GET_NDVAS(bp));
1053 }
1054
1055 if (compress != ZIO_COMPRESS_OFF) {
1056 void *cbuf = zio_buf_alloc(lsize);
1057 psize = zio_compress_data(compress, zio->io_data, cbuf, lsize);
1058 if (psize == 0 || psize == lsize) {
1059 compress = ZIO_COMPRESS_OFF;
1060 zio_buf_free(cbuf, lsize);
1061 } else {
1062 ASSERT(psize < lsize);
1063 zio_push_transform(zio, cbuf, psize, lsize, NULL);
1064 }
1065 }
1066
1067 /*
1068 * The final pass of spa_sync() must be all rewrites, but the first
1069 * few passes offer a trade-off: allocating blocks defers convergence,
1070 * but newly allocated blocks are sequential, so they can be written
1071 * to disk faster. Therefore, we allow the first few passes of
1072 * spa_sync() to allocate new blocks, but force rewrites after that.
1073 * There should only be a handful of blocks after pass 1 in any case.
1074 */
1075 if (!BP_IS_HOLE(bp) && bp->blk_birth == zio->io_txg &&
1076 BP_GET_PSIZE(bp) == psize &&
1077 pass >= zfs_sync_pass_rewrite) {
1078 ASSERT(psize != 0);
1079 enum zio_stage gang_stages = zio->io_pipeline & ZIO_GANG_STAGES;
1080 zio->io_pipeline = ZIO_REWRITE_PIPELINE | gang_stages;
1081 zio->io_flags |= ZIO_FLAG_IO_REWRITE;
1082 } else {
1083 BP_ZERO(bp);
1084 zio->io_pipeline = ZIO_WRITE_PIPELINE;
1085 }
1086
1087 if (psize == 0) {
1088 if (zio->io_bp_orig.blk_birth != 0 &&
1089 spa_feature_is_active(spa, SPA_FEATURE_HOLE_BIRTH)) {
1090 BP_SET_LSIZE(bp, lsize);
1091 BP_SET_TYPE(bp, zp->zp_type);
1092 BP_SET_LEVEL(bp, zp->zp_level);
1093 BP_SET_BIRTH(bp, zio->io_txg, 0);
1094 }
1095 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1096 } else {
1097 ASSERT(zp->zp_checksum != ZIO_CHECKSUM_GANG_HEADER);
1098 BP_SET_LSIZE(bp, lsize);
1099 BP_SET_TYPE(bp, zp->zp_type);
1100 BP_SET_LEVEL(bp, zp->zp_level);
1101 BP_SET_PSIZE(bp, psize);
1102 BP_SET_COMPRESS(bp, compress);
1103 BP_SET_CHECKSUM(bp, zp->zp_checksum);
1104 BP_SET_DEDUP(bp, zp->zp_dedup);
1105 BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER);
1106 if (zp->zp_dedup) {
1107 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1108 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE));
1109 zio->io_pipeline = ZIO_DDT_WRITE_PIPELINE;
1110 }
1111 if (zp->zp_nopwrite) {
1112 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1113 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE));
1114 zio->io_pipeline |= ZIO_STAGE_NOP_WRITE;
1115 }
1116 }
1117
1118 return (ZIO_PIPELINE_CONTINUE);
1119 }
1120
1121 static int
1122 zio_free_bp_init(zio_t *zio)
1123 {
1124 blkptr_t *bp = zio->io_bp;
1125
1126 if (zio->io_child_type == ZIO_CHILD_LOGICAL) {
1127 if (BP_GET_DEDUP(bp))
1128 zio->io_pipeline = ZIO_DDT_FREE_PIPELINE;
1129 }
1130
1131 return (ZIO_PIPELINE_CONTINUE);
1132 }
1133
1134 /*
1135 * ==========================================================================
1136 * Execute the I/O pipeline
1137 * ==========================================================================
1138 */
1139
1140 static void
1141 zio_taskq_dispatch(zio_t *zio, zio_taskq_type_t q, boolean_t cutinline)
1142 {
1143 spa_t *spa = zio->io_spa;
1144 zio_type_t t = zio->io_type;
1145 int flags = (cutinline ? TQ_FRONT : 0);
1146
1147 /*
1148 * If we're a config writer or a probe, the normal issue and
1149 * interrupt threads may all be blocked waiting for the config lock.
1150 * In this case, select the otherwise-unused taskq for ZIO_TYPE_NULL.
1151 */
1152 if (zio->io_flags & (ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_PROBE))
1153 t = ZIO_TYPE_NULL;
1154
1155 /*
1156 * A similar issue exists for the L2ARC write thread until L2ARC 2.0.
1157 */
1158 if (t == ZIO_TYPE_WRITE && zio->io_vd && zio->io_vd->vdev_aux)
1159 t = ZIO_TYPE_NULL;
1160
1161 /*
1162 * If this is a high priority I/O, then use the high priority taskq if
1163 * available.
1164 */
1165 if (zio->io_priority == ZIO_PRIORITY_NOW &&
1166 spa->spa_zio_taskq[t][q + 1].stqs_count != 0)
1167 q++;
1168
1169 ASSERT3U(q, <, ZIO_TASKQ_TYPES);
1170
1171 /*
1172 * NB: We are assuming that the zio can only be dispatched
1173 * to a single taskq at a time. It would be a grievous error
1174 * to dispatch the zio to another taskq at the same time.
1175 */
1176 ASSERT(zio->io_tqent.tqent_next == NULL);
1177 spa_taskq_dispatch_ent(spa, t, q, (task_func_t *)zio_execute, zio,
1178 flags, &zio->io_tqent);
1179 }
1180
1181 static boolean_t
1182 zio_taskq_member(zio_t *zio, zio_taskq_type_t q)
1183 {
1184 kthread_t *executor = zio->io_executor;
1185 spa_t *spa = zio->io_spa;
1186
1187 for (zio_type_t t = 0; t < ZIO_TYPES; t++) {
1188 spa_taskqs_t *tqs = &spa->spa_zio_taskq[t][q];
1189 uint_t i;
1190 for (i = 0; i < tqs->stqs_count; i++) {
1191 if (taskq_member(tqs->stqs_taskq[i], executor))
1192 return (B_TRUE);
1193 }
1194 }
1195
1196 return (B_FALSE);
1197 }
1198
1199 static int
1200 zio_issue_async(zio_t *zio)
1201 {
1202 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE);
1203
1204 return (ZIO_PIPELINE_STOP);
1205 }
1206
1207 void
1208 zio_interrupt(zio_t *zio)
1209 {
1210 zio_taskq_dispatch(zio, ZIO_TASKQ_INTERRUPT, B_FALSE);
1211 }
1212
1213 /*
1214 * Execute the I/O pipeline until one of the following occurs:
1215 *
1216 * (1) the I/O completes
1217 * (2) the pipeline stalls waiting for dependent child I/Os
1218 * (3) the I/O issues, so we're waiting for an I/O completion interrupt
1219 * (4) the I/O is delegated by vdev-level caching or aggregation
1220 * (5) the I/O is deferred due to vdev-level queueing
1221 * (6) the I/O is handed off to another thread.
1222 *
1223 * In all cases, the pipeline stops whenever there's no CPU work; it never
1224 * burns a thread in cv_wait().
1225 *
1226 * There's no locking on io_stage because there's no legitimate way
1227 * for multiple threads to be attempting to process the same I/O.
1228 */
1229 static zio_pipe_stage_t *zio_pipeline[];
1230
1231 void
1232 zio_execute(zio_t *zio)
1233 {
1234 zio->io_executor = curthread;
1235
1236 while (zio->io_stage < ZIO_STAGE_DONE) {
1237 enum zio_stage pipeline = zio->io_pipeline;
1238 enum zio_stage stage = zio->io_stage;
1239 int rv;
1240
1241 ASSERT(!MUTEX_HELD(&zio->io_lock));
1242 ASSERT(ISP2(stage));
1243 ASSERT(zio->io_stall == NULL);
1244
1245 do {
1246 stage <<= 1;
1247 } while ((stage & pipeline) == 0);
1248
1249 ASSERT(stage <= ZIO_STAGE_DONE);
1250
1251 /*
1252 * If we are in interrupt context and this pipeline stage
1253 * will grab a config lock that is held across I/O,
1254 * or may wait for an I/O that needs an interrupt thread
1255 * to complete, issue async to avoid deadlock.
1256 *
1257 * For VDEV_IO_START, we cut in line so that the io will
1258 * be sent to disk promptly.
1259 */
1260 if ((stage & ZIO_BLOCKING_STAGES) && zio->io_vd == NULL &&
1261 zio_taskq_member(zio, ZIO_TASKQ_INTERRUPT)) {
1262 boolean_t cut = (stage == ZIO_STAGE_VDEV_IO_START) ?
1263 zio_requeue_io_start_cut_in_line : B_FALSE;
1264 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, cut);
1265 return;
1266 }
1267
1268 zio->io_stage = stage;
1269 rv = zio_pipeline[highbit64(stage) - 1](zio);
1270
1271 if (rv == ZIO_PIPELINE_STOP)
1272 return;
1273
1274 ASSERT(rv == ZIO_PIPELINE_CONTINUE);
1275 }
1276 }
1277
1278 /*
1279 * ==========================================================================
1280 * Initiate I/O, either sync or async
1281 * ==========================================================================
1282 */
1283 int
1284 zio_wait(zio_t *zio)
1285 {
1286 int error;
1287
1288 ASSERT(zio->io_stage == ZIO_STAGE_OPEN);
1289 ASSERT(zio->io_executor == NULL);
1290
1291 zio->io_waiter = curthread;
1292
1293 zio_execute(zio);
1294
1295 mutex_enter(&zio->io_lock);
1296 while (zio->io_executor != NULL)
1297 cv_wait(&zio->io_cv, &zio->io_lock);
1298 mutex_exit(&zio->io_lock);
1299
1300 error = zio->io_error;
1301 zio_destroy(zio);
1302
1303 return (error);
1304 }
1305
1306 void
1307 zio_nowait(zio_t *zio)
1308 {
1309 ASSERT(zio->io_executor == NULL);
1310
1311 if (zio->io_child_type == ZIO_CHILD_LOGICAL &&
1312 zio_unique_parent(zio) == NULL) {
1313 /*
1314 * This is a logical async I/O with no parent to wait for it.
1315 * We add it to the spa_async_root_zio "Godfather" I/O which
1316 * will ensure they complete prior to unloading the pool.
1317 */
1318 spa_t *spa = zio->io_spa;
1319
1320 zio_add_child(spa->spa_async_zio_root, zio);
1321 }
1322
1323 zio_execute(zio);
1324 }
1325
1326 /*
1327 * ==========================================================================
1328 * Reexecute or suspend/resume failed I/O
1329 * ==========================================================================
1330 */
1331
1332 static void
1333 zio_reexecute(zio_t *pio)
1334 {
1335 zio_t *cio, *cio_next;
1336
1337 ASSERT(pio->io_child_type == ZIO_CHILD_LOGICAL);
1338 ASSERT(pio->io_orig_stage == ZIO_STAGE_OPEN);
1339 ASSERT(pio->io_gang_leader == NULL);
1340 ASSERT(pio->io_gang_tree == NULL);
1341
1342 pio->io_flags = pio->io_orig_flags;
1343 pio->io_stage = pio->io_orig_stage;
1344 pio->io_pipeline = pio->io_orig_pipeline;
1345 pio->io_reexecute = 0;
1346 pio->io_flags |= ZIO_FLAG_REEXECUTED;
1347 pio->io_error = 0;
1348 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
1349 pio->io_state[w] = 0;
1350 for (int c = 0; c < ZIO_CHILD_TYPES; c++)
1351 pio->io_child_error[c] = 0;
1352
1353 if (IO_IS_ALLOCATING(pio))
1354 BP_ZERO(pio->io_bp);
1355
1356 /*
1357 * As we reexecute pio's children, new children could be created.
1358 * New children go to the head of pio's io_child_list, however,
1359 * so we will (correctly) not reexecute them. The key is that
1360 * the remainder of pio's io_child_list, from 'cio_next' onward,
1361 * cannot be affected by any side effects of reexecuting 'cio'.
1362 */
1363 for (cio = zio_walk_children(pio); cio != NULL; cio = cio_next) {
1364 cio_next = zio_walk_children(pio);
1365 mutex_enter(&pio->io_lock);
1366 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
1367 pio->io_children[cio->io_child_type][w]++;
1368 mutex_exit(&pio->io_lock);
1369 zio_reexecute(cio);
1370 }
1371
1372 /*
1373 * Now that all children have been reexecuted, execute the parent.
1374 * We don't reexecute "The Godfather" I/O here as it's the
1375 * responsibility of the caller to wait on him.
1376 */
1377 if (!(pio->io_flags & ZIO_FLAG_GODFATHER))
1378 zio_execute(pio);
1379 }
1380
1381 void
1382 zio_suspend(spa_t *spa, zio_t *zio)
1383 {
1384 if (spa_get_failmode(spa) == ZIO_FAILURE_MODE_PANIC)
1385 fm_panic("Pool '%s' has encountered an uncorrectable I/O "
1386 "failure and the failure mode property for this pool "
1387 "is set to panic.", spa_name(spa));
1388
1389 zfs_ereport_post(FM_EREPORT_ZFS_IO_FAILURE, spa, NULL, NULL, 0, 0);
1390
1391 mutex_enter(&spa->spa_suspend_lock);
1392
1393 if (spa->spa_suspend_zio_root == NULL)
1394 spa->spa_suspend_zio_root = zio_root(spa, NULL, NULL,
1395 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE |
1396 ZIO_FLAG_GODFATHER);
1397
1398 spa->spa_suspended = B_TRUE;
1399
1400 if (zio != NULL) {
1401 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER));
1402 ASSERT(zio != spa->spa_suspend_zio_root);
1403 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1404 ASSERT(zio_unique_parent(zio) == NULL);
1405 ASSERT(zio->io_stage == ZIO_STAGE_DONE);
1406 zio_add_child(spa->spa_suspend_zio_root, zio);
1407 }
1408
1409 mutex_exit(&spa->spa_suspend_lock);
1410 }
1411
1412 int
1413 zio_resume(spa_t *spa)
1414 {
1415 zio_t *pio;
1416
1417 /*
1418 * Reexecute all previously suspended i/o.
1419 */
1420 mutex_enter(&spa->spa_suspend_lock);
1421 spa->spa_suspended = B_FALSE;
1422 cv_broadcast(&spa->spa_suspend_cv);
1423 pio = spa->spa_suspend_zio_root;
1424 spa->spa_suspend_zio_root = NULL;
1425 mutex_exit(&spa->spa_suspend_lock);
1426
1427 if (pio == NULL)
1428 return (0);
1429
1430 zio_reexecute(pio);
1431 return (zio_wait(pio));
1432 }
1433
1434 void
1435 zio_resume_wait(spa_t *spa)
1436 {
1437 mutex_enter(&spa->spa_suspend_lock);
1438 while (spa_suspended(spa))
1439 cv_wait(&spa->spa_suspend_cv, &spa->spa_suspend_lock);
1440 mutex_exit(&spa->spa_suspend_lock);
1441 }
1442
1443 /*
1444 * ==========================================================================
1445 * Gang blocks.
1446 *
1447 * A gang block is a collection of small blocks that looks to the DMU
1448 * like one large block. When zio_dva_allocate() cannot find a block
1449 * of the requested size, due to either severe fragmentation or the pool
1450 * being nearly full, it calls zio_write_gang_block() to construct the
1451 * block from smaller fragments.
1452 *
1453 * A gang block consists of a gang header (zio_gbh_phys_t) and up to
1454 * three (SPA_GBH_NBLKPTRS) gang members. The gang header is just like
1455 * an indirect block: it's an array of block pointers. It consumes
1456 * only one sector and hence is allocatable regardless of fragmentation.
1457 * The gang header's bps point to its gang members, which hold the data.
1458 *
1459 * Gang blocks are self-checksumming, using the bp's <vdev, offset, txg>
1460 * as the verifier to ensure uniqueness of the SHA256 checksum.
1461 * Critically, the gang block bp's blk_cksum is the checksum of the data,
1462 * not the gang header. This ensures that data block signatures (needed for
1463 * deduplication) are independent of how the block is physically stored.
1464 *
1465 * Gang blocks can be nested: a gang member may itself be a gang block.
1466 * Thus every gang block is a tree in which root and all interior nodes are
1467 * gang headers, and the leaves are normal blocks that contain user data.
1468 * The root of the gang tree is called the gang leader.
1469 *
1470 * To perform any operation (read, rewrite, free, claim) on a gang block,
1471 * zio_gang_assemble() first assembles the gang tree (minus data leaves)
1472 * in the io_gang_tree field of the original logical i/o by recursively
1473 * reading the gang leader and all gang headers below it. This yields
1474 * an in-core tree containing the contents of every gang header and the
1475 * bps for every constituent of the gang block.
1476 *
1477 * With the gang tree now assembled, zio_gang_issue() just walks the gang tree
1478 * and invokes a callback on each bp. To free a gang block, zio_gang_issue()
1479 * calls zio_free_gang() -- a trivial wrapper around zio_free() -- for each bp.
1480 * zio_claim_gang() provides a similarly trivial wrapper for zio_claim().
1481 * zio_read_gang() is a wrapper around zio_read() that omits reading gang
1482 * headers, since we already have those in io_gang_tree. zio_rewrite_gang()
1483 * performs a zio_rewrite() of the data or, for gang headers, a zio_rewrite()
1484 * of the gang header plus zio_checksum_compute() of the data to update the
1485 * gang header's blk_cksum as described above.
1486 *
1487 * The two-phase assemble/issue model solves the problem of partial failure --
1488 * what if you'd freed part of a gang block but then couldn't read the
1489 * gang header for another part? Assembling the entire gang tree first
1490 * ensures that all the necessary gang header I/O has succeeded before
1491 * starting the actual work of free, claim, or write. Once the gang tree
1492 * is assembled, free and claim are in-memory operations that cannot fail.
1493 *
1494 * In the event that a gang write fails, zio_dva_unallocate() walks the
1495 * gang tree to immediately free (i.e. insert back into the space map)
1496 * everything we've allocated. This ensures that we don't get ENOSPC
1497 * errors during repeated suspend/resume cycles due to a flaky device.
1498 *
1499 * Gang rewrites only happen during sync-to-convergence. If we can't assemble
1500 * the gang tree, we won't modify the block, so we can safely defer the free
1501 * (knowing that the block is still intact). If we *can* assemble the gang
1502 * tree, then even if some of the rewrites fail, zio_dva_unallocate() will free
1503 * each constituent bp and we can allocate a new block on the next sync pass.
1504 *
1505 * In all cases, the gang tree allows complete recovery from partial failure.
1506 * ==========================================================================
1507 */
1508
1509 static zio_t *
1510 zio_read_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1511 {
1512 if (gn != NULL)
1513 return (pio);
1514
1515 return (zio_read(pio, pio->io_spa, bp, data, BP_GET_PSIZE(bp),
1516 NULL, NULL, pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio),
1517 &pio->io_bookmark));
1518 }
1519
1520 zio_t *
1521 zio_rewrite_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1522 {
1523 zio_t *zio;
1524
1525 if (gn != NULL) {
1526 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp,
1527 gn->gn_gbh, SPA_GANGBLOCKSIZE, NULL, NULL, pio->io_priority,
1528 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
1529 /*
1530 * As we rewrite each gang header, the pipeline will compute
1531 * a new gang block header checksum for it; but no one will
1532 * compute a new data checksum, so we do that here. The one
1533 * exception is the gang leader: the pipeline already computed
1534 * its data checksum because that stage precedes gang assembly.
1535 * (Presently, nothing actually uses interior data checksums;
1536 * this is just good hygiene.)
1537 */
1538 if (gn != pio->io_gang_leader->io_gang_tree) {
1539 zio_checksum_compute(zio, BP_GET_CHECKSUM(bp),
1540 data, BP_GET_PSIZE(bp));
1541 }
1542 /*
1543 * If we are here to damage data for testing purposes,
1544 * leave the GBH alone so that we can detect the damage.
1545 */
1546 if (pio->io_gang_leader->io_flags & ZIO_FLAG_INDUCE_DAMAGE)
1547 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES;
1548 } else {
1549 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp,
1550 data, BP_GET_PSIZE(bp), NULL, NULL, pio->io_priority,
1551 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
1552 }
1553
1554 return (zio);
1555 }
1556
1557 /* ARGSUSED */
1558 zio_t *
1559 zio_free_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1560 {
1561 return (zio_free_sync(pio, pio->io_spa, pio->io_txg, bp,
1562 ZIO_GANG_CHILD_FLAGS(pio)));
1563 }
1564
1565 /* ARGSUSED */
1566 zio_t *
1567 zio_claim_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1568 {
1569 return (zio_claim(pio, pio->io_spa, pio->io_txg, bp,
1570 NULL, NULL, ZIO_GANG_CHILD_FLAGS(pio)));
1571 }
1572
1573 static zio_gang_issue_func_t *zio_gang_issue_func[ZIO_TYPES] = {
1574 NULL,
1575 zio_read_gang,
1576 zio_rewrite_gang,
1577 zio_free_gang,
1578 zio_claim_gang,
1579 NULL
1580 };
1581
1582 static void zio_gang_tree_assemble_done(zio_t *zio);
1583
1584 static zio_gang_node_t *
1585 zio_gang_node_alloc(zio_gang_node_t **gnpp)
1586 {
1587 zio_gang_node_t *gn;
1588
1589 ASSERT(*gnpp == NULL);
1590
1591 gn = kmem_zalloc(sizeof (*gn), KM_SLEEP);
1592 gn->gn_gbh = zio_buf_alloc(SPA_GANGBLOCKSIZE);
1593 *gnpp = gn;
1594
1595 return (gn);
1596 }
1597
1598 static void
1599 zio_gang_node_free(zio_gang_node_t **gnpp)
1600 {
1601 zio_gang_node_t *gn = *gnpp;
1602
1603 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++)
1604 ASSERT(gn->gn_child[g] == NULL);
1605
1606 zio_buf_free(gn->gn_gbh, SPA_GANGBLOCKSIZE);
1607 kmem_free(gn, sizeof (*gn));
1608 *gnpp = NULL;
1609 }
1610
1611 static void
1612 zio_gang_tree_free(zio_gang_node_t **gnpp)
1613 {
1614 zio_gang_node_t *gn = *gnpp;
1615
1616 if (gn == NULL)
1617 return;
1618
1619 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++)
1620 zio_gang_tree_free(&gn->gn_child[g]);
1621
1622 zio_gang_node_free(gnpp);
1623 }
1624
1625 static void
1626 zio_gang_tree_assemble(zio_t *gio, blkptr_t *bp, zio_gang_node_t **gnpp)
1627 {
1628 zio_gang_node_t *gn = zio_gang_node_alloc(gnpp);
1629
1630 ASSERT(gio->io_gang_leader == gio);
1631 ASSERT(BP_IS_GANG(bp));
1632
1633 zio_nowait(zio_read(gio, gio->io_spa, bp, gn->gn_gbh,
1634 SPA_GANGBLOCKSIZE, zio_gang_tree_assemble_done, gn,
1635 gio->io_priority, ZIO_GANG_CHILD_FLAGS(gio), &gio->io_bookmark));
1636 }
1637
1638 static void
1639 zio_gang_tree_assemble_done(zio_t *zio)
1640 {
1641 zio_t *gio = zio->io_gang_leader;
1642 zio_gang_node_t *gn = zio->io_private;
1643 blkptr_t *bp = zio->io_bp;
1644
1645 ASSERT(gio == zio_unique_parent(zio));
1646 ASSERT(zio->io_child_count == 0);
1647
1648 if (zio->io_error)
1649 return;
1650
1651 if (BP_SHOULD_BYTESWAP(bp))
1652 byteswap_uint64_array(zio->io_data, zio->io_size);
1653
1654 ASSERT(zio->io_data == gn->gn_gbh);
1655 ASSERT(zio->io_size == SPA_GANGBLOCKSIZE);
1656 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC);
1657
1658 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
1659 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g];
1660 if (!BP_IS_GANG(gbp))
1661 continue;
1662 zio_gang_tree_assemble(gio, gbp, &gn->gn_child[g]);
1663 }
1664 }
1665
1666 static void
1667 zio_gang_tree_issue(zio_t *pio, zio_gang_node_t *gn, blkptr_t *bp, void *data)
1668 {
1669 zio_t *gio = pio->io_gang_leader;
1670 zio_t *zio;
1671
1672 ASSERT(BP_IS_GANG(bp) == !!gn);
1673 ASSERT(BP_GET_CHECKSUM(bp) == BP_GET_CHECKSUM(gio->io_bp));
1674 ASSERT(BP_GET_LSIZE(bp) == BP_GET_PSIZE(bp) || gn == gio->io_gang_tree);
1675
1676 /*
1677 * If you're a gang header, your data is in gn->gn_gbh.
1678 * If you're a gang member, your data is in 'data' and gn == NULL.
1679 */
1680 zio = zio_gang_issue_func[gio->io_type](pio, bp, gn, data);
1681
1682 if (gn != NULL) {
1683 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC);
1684
1685 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
1686 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g];
1687 if (BP_IS_HOLE(gbp))
1688 continue;
1689 zio_gang_tree_issue(zio, gn->gn_child[g], gbp, data);
1690 data = (char *)data + BP_GET_PSIZE(gbp);
1691 }
1692 }
1693
1694 if (gn == gio->io_gang_tree)
1695 ASSERT3P((char *)gio->io_data + gio->io_size, ==, data);
1696
1697 if (zio != pio)
1698 zio_nowait(zio);
1699 }
1700
1701 static int
1702 zio_gang_assemble(zio_t *zio)
1703 {
1704 blkptr_t *bp = zio->io_bp;
1705
1706 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == NULL);
1707 ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
1708
1709 zio->io_gang_leader = zio;
1710
1711 zio_gang_tree_assemble(zio, bp, &zio->io_gang_tree);
1712
1713 return (ZIO_PIPELINE_CONTINUE);
1714 }
1715
1716 static int
1717 zio_gang_issue(zio_t *zio)
1718 {
1719 blkptr_t *bp = zio->io_bp;
1720
1721 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE))
1722 return (ZIO_PIPELINE_STOP);
1723
1724 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == zio);
1725 ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
1726
1727 if (zio->io_child_error[ZIO_CHILD_GANG] == 0)
1728 zio_gang_tree_issue(zio, zio->io_gang_tree, bp, zio->io_data);
1729 else
1730 zio_gang_tree_free(&zio->io_gang_tree);
1731
1732 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1733
1734 return (ZIO_PIPELINE_CONTINUE);
1735 }
1736
1737 static void
1738 zio_write_gang_member_ready(zio_t *zio)
1739 {
1740 zio_t *pio = zio_unique_parent(zio);
1741 zio_t *gio = zio->io_gang_leader;
1742 dva_t *cdva = zio->io_bp->blk_dva;
1743 dva_t *pdva = pio->io_bp->blk_dva;
1744 uint64_t asize;
1745
1746 if (BP_IS_HOLE(zio->io_bp))
1747 return;
1748
1749 ASSERT(BP_IS_HOLE(&zio->io_bp_orig));
1750
1751 ASSERT(zio->io_child_type == ZIO_CHILD_GANG);
1752 ASSERT3U(zio->io_prop.zp_copies, ==, gio->io_prop.zp_copies);
1753 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(zio->io_bp));
1754 ASSERT3U(pio->io_prop.zp_copies, <=, BP_GET_NDVAS(pio->io_bp));
1755 ASSERT3U(BP_GET_NDVAS(zio->io_bp), <=, BP_GET_NDVAS(pio->io_bp));
1756
1757 mutex_enter(&pio->io_lock);
1758 for (int d = 0; d < BP_GET_NDVAS(zio->io_bp); d++) {
1759 ASSERT(DVA_GET_GANG(&pdva[d]));
1760 asize = DVA_GET_ASIZE(&pdva[d]);
1761 asize += DVA_GET_ASIZE(&cdva[d]);
1762 DVA_SET_ASIZE(&pdva[d], asize);
1763 }
1764 mutex_exit(&pio->io_lock);
1765 }
1766
1767 static int
1768 zio_write_gang_block(zio_t *pio)
1769 {
1770 spa_t *spa = pio->io_spa;
1771 blkptr_t *bp = pio->io_bp;
1772 zio_t *gio = pio->io_gang_leader;
1773 zio_t *zio;
1774 zio_gang_node_t *gn, **gnpp;
1775 zio_gbh_phys_t *gbh;
1776 uint64_t txg = pio->io_txg;
1777 uint64_t resid = pio->io_size;
1778 uint64_t lsize;
1779 int copies = gio->io_prop.zp_copies;
1780 int gbh_copies = MIN(copies + 1, spa_max_replication(spa));
1781 zio_prop_t zp;
1782 int error;
1783
1784 error = metaslab_alloc(spa, spa_normal_class(spa), SPA_GANGBLOCKSIZE,
1785 bp, gbh_copies, txg, pio == gio ? NULL : gio->io_bp,
1786 METASLAB_HINTBP_FAVOR | METASLAB_GANG_HEADER);
1787 if (error) {
1788 pio->io_error = error;
1789 return (ZIO_PIPELINE_CONTINUE);
1790 }
1791
1792 if (pio == gio) {
1793 gnpp = &gio->io_gang_tree;
1794 } else {
1795 gnpp = pio->io_private;
1796 ASSERT(pio->io_ready == zio_write_gang_member_ready);
1797 }
1798
1799 gn = zio_gang_node_alloc(gnpp);
1800 gbh = gn->gn_gbh;
1801 bzero(gbh, SPA_GANGBLOCKSIZE);
1802
1803 /*
1804 * Create the gang header.
1805 */
1806 zio = zio_rewrite(pio, spa, txg, bp, gbh, SPA_GANGBLOCKSIZE, NULL, NULL,
1807 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
1808
1809 /*
1810 * Create and nowait the gang children.
1811 */
1812 for (int g = 0; resid != 0; resid -= lsize, g++) {
1813 lsize = P2ROUNDUP(resid / (SPA_GBH_NBLKPTRS - g),
1814 SPA_MINBLOCKSIZE);
1815 ASSERT(lsize >= SPA_MINBLOCKSIZE && lsize <= resid);
1816
1817 zp.zp_checksum = gio->io_prop.zp_checksum;
1818 zp.zp_compress = ZIO_COMPRESS_OFF;
1819 zp.zp_type = DMU_OT_NONE;
1820 zp.zp_level = 0;
1821 zp.zp_copies = gio->io_prop.zp_copies;
1822 zp.zp_dedup = B_FALSE;
1823 zp.zp_dedup_verify = B_FALSE;
1824 zp.zp_nopwrite = B_FALSE;
1825
1826 zio_nowait(zio_write(zio, spa, txg, &gbh->zg_blkptr[g],
1827 (char *)pio->io_data + (pio->io_size - resid), lsize, &zp,
1828 zio_write_gang_member_ready, NULL, NULL, &gn->gn_child[g],
1829 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio),
1830 &pio->io_bookmark));
1831 }
1832
1833 /*
1834 * Set pio's pipeline to just wait for zio to finish.
1835 */
1836 pio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1837
1838 zio_nowait(zio);
1839
1840 return (ZIO_PIPELINE_CONTINUE);
1841 }
1842
1843 /*
1844 * The zio_nop_write stage in the pipeline determines if allocating
1845 * a new bp is necessary. By leveraging a cryptographically secure checksum,
1846 * such as SHA256, we can compare the checksums of the new data and the old
1847 * to determine if allocating a new block is required. The nopwrite
1848 * feature can handle writes in either syncing or open context (i.e. zil
1849 * writes) and as a result is mutually exclusive with dedup.
1850 */
1851 static int
1852 zio_nop_write(zio_t *zio)
1853 {
1854 blkptr_t *bp = zio->io_bp;
1855 blkptr_t *bp_orig = &zio->io_bp_orig;
1856 zio_prop_t *zp = &zio->io_prop;
1857
1858 ASSERT(BP_GET_LEVEL(bp) == 0);
1859 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE));
1860 ASSERT(zp->zp_nopwrite);
1861 ASSERT(!zp->zp_dedup);
1862 ASSERT(zio->io_bp_override == NULL);
1863 ASSERT(IO_IS_ALLOCATING(zio));
1864
1865 /*
1866 * Check to see if the original bp and the new bp have matching
1867 * characteristics (i.e. same checksum, compression algorithms, etc).
1868 * If they don't then just continue with the pipeline which will
1869 * allocate a new bp.
1870 */
1871 if (BP_IS_HOLE(bp_orig) ||
1872 !zio_checksum_table[BP_GET_CHECKSUM(bp)].ci_dedup ||
1873 BP_GET_CHECKSUM(bp) != BP_GET_CHECKSUM(bp_orig) ||
1874 BP_GET_COMPRESS(bp) != BP_GET_COMPRESS(bp_orig) ||
1875 BP_GET_DEDUP(bp) != BP_GET_DEDUP(bp_orig) ||
1876 zp->zp_copies != BP_GET_NDVAS(bp_orig))
1877 return (ZIO_PIPELINE_CONTINUE);
1878
1879 /*
1880 * If the checksums match then reset the pipeline so that we
1881 * avoid allocating a new bp and issuing any I/O.
1882 */
1883 if (ZIO_CHECKSUM_EQUAL(bp->blk_cksum, bp_orig->blk_cksum)) {
1884 ASSERT(zio_checksum_table[zp->zp_checksum].ci_dedup);
1885 ASSERT3U(BP_GET_PSIZE(bp), ==, BP_GET_PSIZE(bp_orig));
1886 ASSERT3U(BP_GET_LSIZE(bp), ==, BP_GET_LSIZE(bp_orig));
1887 ASSERT(zp->zp_compress != ZIO_COMPRESS_OFF);
1888 ASSERT(bcmp(&bp->blk_prop, &bp_orig->blk_prop,
1889 sizeof (uint64_t)) == 0);
1890
1891 *bp = *bp_orig;
1892 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1893 zio->io_flags |= ZIO_FLAG_NOPWRITE;
1894 }
1895
1896 return (ZIO_PIPELINE_CONTINUE);
1897 }
1898
1899 /*
1900 * ==========================================================================
1901 * Dedup
1902 * ==========================================================================
1903 */
1904 static void
1905 zio_ddt_child_read_done(zio_t *zio)
1906 {
1907 blkptr_t *bp = zio->io_bp;
1908 ddt_entry_t *dde = zio->io_private;
1909 ddt_phys_t *ddp;
1910 zio_t *pio = zio_unique_parent(zio);
1911
1912 mutex_enter(&pio->io_lock);
1913 ddp = ddt_phys_select(dde, bp);
1914 if (zio->io_error == 0)
1915 ddt_phys_clear(ddp); /* this ddp doesn't need repair */
1916 if (zio->io_error == 0 && dde->dde_repair_data == NULL)
1917 dde->dde_repair_data = zio->io_data;
1918 else
1919 zio_buf_free(zio->io_data, zio->io_size);
1920 mutex_exit(&pio->io_lock);
1921 }
1922
1923 static int
1924 zio_ddt_read_start(zio_t *zio)
1925 {
1926 blkptr_t *bp = zio->io_bp;
1927
1928 ASSERT(BP_GET_DEDUP(bp));
1929 ASSERT(BP_GET_PSIZE(bp) == zio->io_size);
1930 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1931
1932 if (zio->io_child_error[ZIO_CHILD_DDT]) {
1933 ddt_t *ddt = ddt_select(zio->io_spa, bp);
1934 ddt_entry_t *dde = ddt_repair_start(ddt, bp);
1935 ddt_phys_t *ddp = dde->dde_phys;
1936 ddt_phys_t *ddp_self = ddt_phys_select(dde, bp);
1937 blkptr_t blk;
1938
1939 ASSERT(zio->io_vsd == NULL);
1940 zio->io_vsd = dde;
1941
1942 if (ddp_self == NULL)
1943 return (ZIO_PIPELINE_CONTINUE);
1944
1945 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
1946 if (ddp->ddp_phys_birth == 0 || ddp == ddp_self)
1947 continue;
1948 ddt_bp_create(ddt->ddt_checksum, &dde->dde_key, ddp,
1949 &blk);
1950 zio_nowait(zio_read(zio, zio->io_spa, &blk,
1951 zio_buf_alloc(zio->io_size), zio->io_size,
1952 zio_ddt_child_read_done, dde, zio->io_priority,
1953 ZIO_DDT_CHILD_FLAGS(zio) | ZIO_FLAG_DONT_PROPAGATE,
1954 &zio->io_bookmark));
1955 }
1956 return (ZIO_PIPELINE_CONTINUE);
1957 }
1958
1959 zio_nowait(zio_read(zio, zio->io_spa, bp,
1960 zio->io_data, zio->io_size, NULL, NULL, zio->io_priority,
1961 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark));
1962
1963 return (ZIO_PIPELINE_CONTINUE);
1964 }
1965
1966 static int
1967 zio_ddt_read_done(zio_t *zio)
1968 {
1969 blkptr_t *bp = zio->io_bp;
1970
1971 if (zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE))
1972 return (ZIO_PIPELINE_STOP);
1973
1974 ASSERT(BP_GET_DEDUP(bp));
1975 ASSERT(BP_GET_PSIZE(bp) == zio->io_size);
1976 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1977
1978 if (zio->io_child_error[ZIO_CHILD_DDT]) {
1979 ddt_t *ddt = ddt_select(zio->io_spa, bp);
1980 ddt_entry_t *dde = zio->io_vsd;
1981 if (ddt == NULL) {
1982 ASSERT(spa_load_state(zio->io_spa) != SPA_LOAD_NONE);
1983 return (ZIO_PIPELINE_CONTINUE);
1984 }
1985 if (dde == NULL) {
1986 zio->io_stage = ZIO_STAGE_DDT_READ_START >> 1;
1987 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE);
1988 return (ZIO_PIPELINE_STOP);
1989 }
1990 if (dde->dde_repair_data != NULL) {
1991 bcopy(dde->dde_repair_data, zio->io_data, zio->io_size);
1992 zio->io_child_error[ZIO_CHILD_DDT] = 0;
1993 }
1994 ddt_repair_done(ddt, dde);
1995 zio->io_vsd = NULL;
1996 }
1997
1998 ASSERT(zio->io_vsd == NULL);
1999
2000 return (ZIO_PIPELINE_CONTINUE);
2001 }
2002
2003 static boolean_t
2004 zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde)
2005 {
2006 spa_t *spa = zio->io_spa;
2007
2008 /*
2009 * Note: we compare the original data, not the transformed data,
2010 * because when zio->io_bp is an override bp, we will not have
2011 * pushed the I/O transforms. That's an important optimization
2012 * because otherwise we'd compress/encrypt all dmu_sync() data twice.
2013 */
2014 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
2015 zio_t *lio = dde->dde_lead_zio[p];
2016
2017 if (lio != NULL) {
2018 return (lio->io_orig_size != zio->io_orig_size ||
2019 bcmp(zio->io_orig_data, lio->io_orig_data,
2020 zio->io_orig_size) != 0);
2021 }
2022 }
2023
2024 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
2025 ddt_phys_t *ddp = &dde->dde_phys[p];
2026
2027 if (ddp->ddp_phys_birth != 0) {
2028 arc_buf_t *abuf = NULL;
2029 uint32_t aflags = ARC_WAIT;
2030 blkptr_t blk = *zio->io_bp;
2031 int error;
2032
2033 ddt_bp_fill(ddp, &blk, ddp->ddp_phys_birth);
2034
2035 ddt_exit(ddt);
2036
2037 error = arc_read(NULL, spa, &blk,
2038 arc_getbuf_func, &abuf, ZIO_PRIORITY_SYNC_READ,
2039 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
2040 &aflags, &zio->io_bookmark);
2041
2042 if (error == 0) {
2043 if (arc_buf_size(abuf) != zio->io_orig_size ||
2044 bcmp(abuf->b_data, zio->io_orig_data,
2045 zio->io_orig_size) != 0)
2046 error = SET_ERROR(EEXIST);
2047 VERIFY(arc_buf_remove_ref(abuf, &abuf));
2048 }
2049
2050 ddt_enter(ddt);
2051 return (error != 0);
2052 }
2053 }
2054
2055 return (B_FALSE);
2056 }
2057
2058 static void
2059 zio_ddt_child_write_ready(zio_t *zio)
2060 {
2061 int p = zio->io_prop.zp_copies;
2062 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp);
2063 ddt_entry_t *dde = zio->io_private;
2064 ddt_phys_t *ddp = &dde->dde_phys[p];
2065 zio_t *pio;
2066
2067 if (zio->io_error)
2068 return;
2069
2070 ddt_enter(ddt);
2071
2072 ASSERT(dde->dde_lead_zio[p] == zio);
2073
2074 ddt_phys_fill(ddp, zio->io_bp);
2075
2076 while ((pio = zio_walk_parents(zio)) != NULL)
2077 ddt_bp_fill(ddp, pio->io_bp, zio->io_txg);
2078
2079 ddt_exit(ddt);
2080 }
2081
2082 static void
2083 zio_ddt_child_write_done(zio_t *zio)
2084 {
2085 int p = zio->io_prop.zp_copies;
2086 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp);
2087 ddt_entry_t *dde = zio->io_private;
2088 ddt_phys_t *ddp = &dde->dde_phys[p];
2089
2090 ddt_enter(ddt);
2091
2092 ASSERT(ddp->ddp_refcnt == 0);
2093 ASSERT(dde->dde_lead_zio[p] == zio);
2094 dde->dde_lead_zio[p] = NULL;
2095
2096 if (zio->io_error == 0) {
2097 while (zio_walk_parents(zio) != NULL)
2098 ddt_phys_addref(ddp);
2099 } else {
2100 ddt_phys_clear(ddp);
2101 }
2102
2103 ddt_exit(ddt);
2104 }
2105
2106 static void
2107 zio_ddt_ditto_write_done(zio_t *zio)
2108 {
2109 int p = DDT_PHYS_DITTO;
2110 zio_prop_t *zp = &zio->io_prop;
2111 blkptr_t *bp = zio->io_bp;
2112 ddt_t *ddt = ddt_select(zio->io_spa, bp);
2113 ddt_entry_t *dde = zio->io_private;
2114 ddt_phys_t *ddp = &dde->dde_phys[p];
2115 ddt_key_t *ddk = &dde->dde_key;
2116
2117 ddt_enter(ddt);
2118
2119 ASSERT(ddp->ddp_refcnt == 0);
2120 ASSERT(dde->dde_lead_zio[p] == zio);
2121 dde->dde_lead_zio[p] = NULL;
2122
2123 if (zio->io_error == 0) {
2124 ASSERT(ZIO_CHECKSUM_EQUAL(bp->blk_cksum, ddk->ddk_cksum));
2125 ASSERT(zp->zp_copies < SPA_DVAS_PER_BP);
2126 ASSERT(zp->zp_copies == BP_GET_NDVAS(bp) - BP_IS_GANG(bp));
2127 if (ddp->ddp_phys_birth != 0)
2128 ddt_phys_free(ddt, ddk, ddp, zio->io_txg);
2129 ddt_phys_fill(ddp, bp);
2130 }
2131
2132 ddt_exit(ddt);
2133 }
2134
2135 static int
2136 zio_ddt_write(zio_t *zio)
2137 {
2138 spa_t *spa = zio->io_spa;
2139 blkptr_t *bp = zio->io_bp;
2140 uint64_t txg = zio->io_txg;
2141 zio_prop_t *zp = &zio->io_prop;
2142 int p = zp->zp_copies;
2143 int ditto_copies;
2144 zio_t *cio = NULL;
2145 zio_t *dio = NULL;
2146 ddt_t *ddt = ddt_select(spa, bp);
2147 ddt_entry_t *dde;
2148 ddt_phys_t *ddp;
2149
2150 ASSERT(BP_GET_DEDUP(bp));
2151 ASSERT(BP_GET_CHECKSUM(bp) == zp->zp_checksum);
2152 ASSERT(BP_IS_HOLE(bp) || zio->io_bp_override);
2153
2154 ddt_enter(ddt);
2155 dde = ddt_lookup(ddt, bp, B_TRUE);
2156 ddp = &dde->dde_phys[p];
2157
2158 if (zp->zp_dedup_verify && zio_ddt_collision(zio, ddt, dde)) {
2159 /*
2160 * If we're using a weak checksum, upgrade to a strong checksum
2161 * and try again. If we're already using a strong checksum,
2162 * we can't resolve it, so just convert to an ordinary write.
2163 * (And automatically e-mail a paper to Nature?)
2164 */
2165 if (!zio_checksum_table[zp->zp_checksum].ci_dedup) {
2166 zp->zp_checksum = spa_dedup_checksum(spa);
2167 zio_pop_transforms(zio);
2168 zio->io_stage = ZIO_STAGE_OPEN;
2169 BP_ZERO(bp);
2170 } else {
2171 zp->zp_dedup = B_FALSE;
2172 }
2173 zio->io_pipeline = ZIO_WRITE_PIPELINE;
2174 ddt_exit(ddt);
2175 return (ZIO_PIPELINE_CONTINUE);
2176 }
2177
2178 ditto_copies = ddt_ditto_copies_needed(ddt, dde, ddp);
2179 ASSERT(ditto_copies < SPA_DVAS_PER_BP);
2180
2181 if (ditto_copies > ddt_ditto_copies_present(dde) &&
2182 dde->dde_lead_zio[DDT_PHYS_DITTO] == NULL) {
2183 zio_prop_t czp = *zp;
2184
2185 czp.zp_copies = ditto_copies;
2186
2187 /*
2188 * If we arrived here with an override bp, we won't have run
2189 * the transform stack, so we won't have the data we need to
2190 * generate a child i/o. So, toss the override bp and restart.
2191 * This is safe, because using the override bp is just an
2192 * optimization; and it's rare, so the cost doesn't matter.
2193 */
2194 if (zio->io_bp_override) {
2195 zio_pop_transforms(zio);
2196 zio->io_stage = ZIO_STAGE_OPEN;
2197 zio->io_pipeline = ZIO_WRITE_PIPELINE;
2198 zio->io_bp_override = NULL;
2199 BP_ZERO(bp);
2200 ddt_exit(ddt);
2201 return (ZIO_PIPELINE_CONTINUE);
2202 }
2203
2204 dio = zio_write(zio, spa, txg, bp, zio->io_orig_data,
2205 zio->io_orig_size, &czp, NULL, NULL,
2206 zio_ddt_ditto_write_done, dde, zio->io_priority,
2207 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark);
2208
2209 zio_push_transform(dio, zio->io_data, zio->io_size, 0, NULL);
2210 dde->dde_lead_zio[DDT_PHYS_DITTO] = dio;
2211 }
2212
2213 if (ddp->ddp_phys_birth != 0 || dde->dde_lead_zio[p] != NULL) {
2214 if (ddp->ddp_phys_birth != 0)
2215 ddt_bp_fill(ddp, bp, txg);
2216 if (dde->dde_lead_zio[p] != NULL)
2217 zio_add_child(zio, dde->dde_lead_zio[p]);
2218 else
2219 ddt_phys_addref(ddp);
2220 } else if (zio->io_bp_override) {
2221 ASSERT(bp->blk_birth == txg);
2222 ASSERT(BP_EQUAL(bp, zio->io_bp_override));
2223 ddt_phys_fill(ddp, bp);
2224 ddt_phys_addref(ddp);
2225 } else {
2226 cio = zio_write(zio, spa, txg, bp, zio->io_orig_data,
2227 zio->io_orig_size, zp, zio_ddt_child_write_ready, NULL,
2228 zio_ddt_child_write_done, dde, zio->io_priority,
2229 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark);
2230
2231 zio_push_transform(cio, zio->io_data, zio->io_size, 0, NULL);
2232 dde->dde_lead_zio[p] = cio;
2233 }
2234
2235 ddt_exit(ddt);
2236
2237 if (cio)
2238 zio_nowait(cio);
2239 if (dio)
2240 zio_nowait(dio);
2241
2242 return (ZIO_PIPELINE_CONTINUE);
2243 }
2244
2245 ddt_entry_t *freedde; /* for debugging */
2246
2247 static int
2248 zio_ddt_free(zio_t *zio)
2249 {
2250 spa_t *spa = zio->io_spa;
2251 blkptr_t *bp = zio->io_bp;
2252 ddt_t *ddt = ddt_select(spa, bp);
2253 ddt_entry_t *dde;
2254 ddt_phys_t *ddp;
2255
2256 ASSERT(BP_GET_DEDUP(bp));
2257 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
2258
2259 ddt_enter(ddt);
2260 freedde = dde = ddt_lookup(ddt, bp, B_TRUE);
2261 ddp = ddt_phys_select(dde, bp);
2262 ddt_phys_decref(ddp);
2263 ddt_exit(ddt);
2264
2265 return (ZIO_PIPELINE_CONTINUE);
2266 }
2267
2268 /*
2269 * ==========================================================================
2270 * Allocate and free blocks
2271 * ==========================================================================
2272 */
2273 static int
2274 zio_dva_allocate(zio_t *zio)
2275 {
2276 spa_t *spa = zio->io_spa;
2277 metaslab_class_t *mc = spa_normal_class(spa);
2278 blkptr_t *bp = zio->io_bp;
2279 int error;
2280 int flags = 0;
2281
2282 if (zio->io_gang_leader == NULL) {
2283 ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
2284 zio->io_gang_leader = zio;
2285 }
2286
2287 ASSERT(BP_IS_HOLE(bp));
2288 ASSERT0(BP_GET_NDVAS(bp));
2289 ASSERT3U(zio->io_prop.zp_copies, >, 0);
2290 ASSERT3U(zio->io_prop.zp_copies, <=, spa_max_replication(spa));
2291 ASSERT3U(zio->io_size, ==, BP_GET_PSIZE(bp));
2292
2293 /*
2294 * The dump device does not support gang blocks so allocation on
2295 * behalf of the dump device (i.e. ZIO_FLAG_NODATA) must avoid
2296 * the "fast" gang feature.
2297 */
2298 flags |= (zio->io_flags & ZIO_FLAG_NODATA) ? METASLAB_GANG_AVOID : 0;
2299 flags |= (zio->io_flags & ZIO_FLAG_GANG_CHILD) ?
2300 METASLAB_GANG_CHILD : 0;
2301 error = metaslab_alloc(spa, mc, zio->io_size, bp,
2302 zio->io_prop.zp_copies, zio->io_txg, NULL, flags);
2303
2304 if (error) {
2305 spa_dbgmsg(spa, "%s: metaslab allocation failure: zio %p, "
2306 "size %llu, error %d", spa_name(spa), zio, zio->io_size,
2307 error);
2308 if (error == ENOSPC && zio->io_size > SPA_MINBLOCKSIZE)
2309 return (zio_write_gang_block(zio));
2310 zio->io_error = error;
2311 }
2312
2313 return (ZIO_PIPELINE_CONTINUE);
2314 }
2315
2316 static int
2317 zio_dva_free(zio_t *zio)
2318 {
2319 metaslab_free(zio->io_spa, zio->io_bp, zio->io_txg, B_FALSE);
2320
2321 return (ZIO_PIPELINE_CONTINUE);
2322 }
2323
2324 static int
2325 zio_dva_claim(zio_t *zio)
2326 {
2327 int error;
2328
2329 error = metaslab_claim(zio->io_spa, zio->io_bp, zio->io_txg);
2330 if (error)
2331 zio->io_error = error;
2332
2333 return (ZIO_PIPELINE_CONTINUE);
2334 }
2335
2336 /*
2337 * Undo an allocation. This is used by zio_done() when an I/O fails
2338 * and we want to give back the block we just allocated.
2339 * This handles both normal blocks and gang blocks.
2340 */
2341 static void
2342 zio_dva_unallocate(zio_t *zio, zio_gang_node_t *gn, blkptr_t *bp)
2343 {
2344 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp));
2345 ASSERT(zio->io_bp_override == NULL);
2346
2347 if (!BP_IS_HOLE(bp))
2348 metaslab_free(zio->io_spa, bp, bp->blk_birth, B_TRUE);
2349
2350 if (gn != NULL) {
2351 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
2352 zio_dva_unallocate(zio, gn->gn_child[g],
2353 &gn->gn_gbh->zg_blkptr[g]);
2354 }
2355 }
2356 }
2357
2358 /*
2359 * Try to allocate an intent log block. Return 0 on success, errno on failure.
2360 */
2361 int
2362 zio_alloc_zil(spa_t *spa, uint64_t txg, blkptr_t *new_bp, blkptr_t *old_bp,
2363 uint64_t size, boolean_t use_slog)
2364 {
2365 int error = 1;
2366
2367 ASSERT(txg > spa_syncing_txg(spa));
2368
2369 /*
2370 * ZIL blocks are always contiguous (i.e. not gang blocks) so we
2371 * set the METASLAB_GANG_AVOID flag so that they don't "fast gang"
2372 * when allocating them.
2373 */
2374 if (use_slog) {
2375 error = metaslab_alloc(spa, spa_log_class(spa), size,
2376 new_bp, 1, txg, old_bp,
2377 METASLAB_HINTBP_AVOID | METASLAB_GANG_AVOID);
2378 }
2379
2380 if (error) {
2381 error = metaslab_alloc(spa, spa_normal_class(spa), size,
2382 new_bp, 1, txg, old_bp,
2383 METASLAB_HINTBP_AVOID);
2384 }
2385
2386 if (error == 0) {
2387 BP_SET_LSIZE(new_bp, size);
2388 BP_SET_PSIZE(new_bp, size);
2389 BP_SET_COMPRESS(new_bp, ZIO_COMPRESS_OFF);
2390 BP_SET_CHECKSUM(new_bp,
2391 spa_version(spa) >= SPA_VERSION_SLIM_ZIL
2392 ? ZIO_CHECKSUM_ZILOG2 : ZIO_CHECKSUM_ZILOG);
2393 BP_SET_TYPE(new_bp, DMU_OT_INTENT_LOG);
2394 BP_SET_LEVEL(new_bp, 0);
2395 BP_SET_DEDUP(new_bp, 0);
2396 BP_SET_BYTEORDER(new_bp, ZFS_HOST_BYTEORDER);
2397 }
2398
2399 return (error);
2400 }
2401
2402 /*
2403 * Free an intent log block.
2404 */
2405 void
2406 zio_free_zil(spa_t *spa, uint64_t txg, blkptr_t *bp)
2407 {
2408 ASSERT(BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG);
2409 ASSERT(!BP_IS_GANG(bp));
2410
2411 zio_free(spa, txg, bp);
2412 }
2413
2414 /*
2415 * ==========================================================================
2416 * Read and write to physical devices
2417 * ==========================================================================
2418 */
2419 static int
2420 zio_vdev_io_start(zio_t *zio)
2421 {
2422 vdev_t *vd = zio->io_vd;
2423 uint64_t align;
2424 spa_t *spa = zio->io_spa;
2425
2426 ASSERT(zio->io_error == 0);
2427 ASSERT(zio->io_child_error[ZIO_CHILD_VDEV] == 0);
2428
2429 if (vd == NULL) {
2430 if (!(zio->io_flags & ZIO_FLAG_CONFIG_WRITER))
2431 spa_config_enter(spa, SCL_ZIO, zio, RW_READER);
2432
2433 /*
2434 * The mirror_ops handle multiple DVAs in a single BP.
2435 */
2436 return (vdev_mirror_ops.vdev_op_io_start(zio));
2437 }
2438
2439 /*
2440 * We keep track of time-sensitive I/Os so that the scan thread
2441 * can quickly react to certain workloads. In particular, we care
2442 * about non-scrubbing, top-level reads and writes with the following
2443 * characteristics:
2444 * - synchronous writes of user data to non-slog devices
2445 * - any reads of user data
2446 * When these conditions are met, adjust the timestamp of spa_last_io
2447 * which allows the scan thread to adjust its workload accordingly.
2448 */
2449 if (!(zio->io_flags & ZIO_FLAG_SCAN_THREAD) && zio->io_bp != NULL &&
2450 vd == vd->vdev_top && !vd->vdev_islog &&
2451 zio->io_bookmark.zb_objset != DMU_META_OBJSET &&
2452 zio->io_txg != spa_syncing_txg(spa)) {
2453 uint64_t old = spa->spa_last_io;
2454 uint64_t new = ddi_get_lbolt64();
2455 if (old != new)
2456 (void) atomic_cas_64(&spa->spa_last_io, old, new);
2457 }
2458
2459 align = 1ULL << vd->vdev_top->vdev_ashift;
2460
2461 if (P2PHASE(zio->io_size, align) != 0) {
2462 uint64_t asize = P2ROUNDUP(zio->io_size, align);
2463 char *abuf = zio_buf_alloc(asize);
2464 ASSERT(vd == vd->vdev_top);
2465 if (zio->io_type == ZIO_TYPE_WRITE) {
2466 bcopy(zio->io_data, abuf, zio->io_size);
2467 bzero(abuf + zio->io_size, asize - zio->io_size);
2468 }
2469 zio_push_transform(zio, abuf, asize, asize, zio_subblock);
2470 }
2471
2472 ASSERT(P2PHASE(zio->io_offset, align) == 0);
2473 ASSERT(P2PHASE(zio->io_size, align) == 0);
2474 VERIFY(zio->io_type != ZIO_TYPE_WRITE || spa_writeable(spa));
2475
2476 /*
2477 * If this is a repair I/O, and there's no self-healing involved --
2478 * that is, we're just resilvering what we expect to resilver --
2479 * then don't do the I/O unless zio's txg is actually in vd's DTL.
2480 * This prevents spurious resilvering with nested replication.
2481 * For example, given a mirror of mirrors, (A+B)+(C+D), if only
2482 * A is out of date, we'll read from C+D, then use the data to
2483 * resilver A+B -- but we don't actually want to resilver B, just A.
2484 * The top-level mirror has no way to know this, so instead we just
2485 * discard unnecessary repairs as we work our way down the vdev tree.
2486 * The same logic applies to any form of nested replication:
2487 * ditto + mirror, RAID-Z + replacing, etc. This covers them all.
2488 */
2489 if ((zio->io_flags & ZIO_FLAG_IO_REPAIR) &&
2490 !(zio->io_flags & ZIO_FLAG_SELF_HEAL) &&
2491 zio->io_txg != 0 && /* not a delegated i/o */
2492 !vdev_dtl_contains(vd, DTL_PARTIAL, zio->io_txg, 1)) {
2493 ASSERT(zio->io_type == ZIO_TYPE_WRITE);
2494 zio_vdev_io_bypass(zio);
2495 return (ZIO_PIPELINE_CONTINUE);
2496 }
2497
2498 if (vd->vdev_ops->vdev_op_leaf &&
2499 (zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE)) {
2500
2501 if (zio->io_type == ZIO_TYPE_READ && vdev_cache_read(zio))
2502 return (ZIO_PIPELINE_CONTINUE);
2503
2504 if ((zio = vdev_queue_io(zio)) == NULL)
2505 return (ZIO_PIPELINE_STOP);
2506
2507 if (!vdev_accessible(vd, zio)) {
2508 zio->io_error = SET_ERROR(ENXIO);
2509 zio_interrupt(zio);
2510 return (ZIO_PIPELINE_STOP);
2511 }
2512 }
2513
2514 return (vd->vdev_ops->vdev_op_io_start(zio));
2515 }
2516
2517 static int
2518 zio_vdev_io_done(zio_t *zio)
2519 {
2520 vdev_t *vd = zio->io_vd;
2521 vdev_ops_t *ops = vd ? vd->vdev_ops : &vdev_mirror_ops;
2522 boolean_t unexpected_error = B_FALSE;
2523
2524 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE))
2525 return (ZIO_PIPELINE_STOP);
2526
2527 ASSERT(zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE);
2528
2529 if (vd != NULL && vd->vdev_ops->vdev_op_leaf) {
2530
2531 vdev_queue_io_done(zio);
2532
2533 if (zio->io_type == ZIO_TYPE_WRITE)
2534 vdev_cache_write(zio);
2535
2536 if (zio_injection_enabled && zio->io_error == 0)
2537 zio->io_error = zio_handle_device_injection(vd,
2538 zio, EIO);
2539
2540 if (zio_injection_enabled && zio->io_error == 0)
2541 zio->io_error = zio_handle_label_injection(zio, EIO);
2542
2543 if (zio->io_error) {
2544 if (!vdev_accessible(vd, zio)) {
2545 zio->io_error = SET_ERROR(ENXIO);
2546 } else {
2547 unexpected_error = B_TRUE;
2548 }
2549 }
2550 }
2551
2552 ops->vdev_op_io_done(zio);
2553
2554 if (unexpected_error)
2555 VERIFY(vdev_probe(vd, zio) == NULL);
2556
2557 return (ZIO_PIPELINE_CONTINUE);
2558 }
2559
2560 /*
2561 * For non-raidz ZIOs, we can just copy aside the bad data read from the
2562 * disk, and use that to finish the checksum ereport later.
2563 */
2564 static void
2565 zio_vsd_default_cksum_finish(zio_cksum_report_t *zcr,
2566 const void *good_buf)
2567 {
2568 /* no processing needed */
2569 zfs_ereport_finish_checksum(zcr, good_buf, zcr->zcr_cbdata, B_FALSE);
2570 }
2571
2572 /*ARGSUSED*/
2573 void
2574 zio_vsd_default_cksum_report(zio_t *zio, zio_cksum_report_t *zcr, void *ignored)
2575 {
2576 void *buf = zio_buf_alloc(zio->io_size);
2577
2578 bcopy(zio->io_data, buf, zio->io_size);
2579
2580 zcr->zcr_cbinfo = zio->io_size;
2581 zcr->zcr_cbdata = buf;
2582 zcr->zcr_finish = zio_vsd_default_cksum_finish;
2583 zcr->zcr_free = zio_buf_free;
2584 }
2585
2586 static int
2587 zio_vdev_io_assess(zio_t *zio)
2588 {
2589 vdev_t *vd = zio->io_vd;
2590
2591 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE))
2592 return (ZIO_PIPELINE_STOP);
2593
2594 if (vd == NULL && !(zio->io_flags & ZIO_FLAG_CONFIG_WRITER))
2595 spa_config_exit(zio->io_spa, SCL_ZIO, zio);
2596
2597 if (zio->io_vsd != NULL) {
2598 zio->io_vsd_ops->vsd_free(zio);
2599 zio->io_vsd = NULL;
2600 }
2601
2602 if (zio_injection_enabled && zio->io_error == 0)
2603 zio->io_error = zio_handle_fault_injection(zio, EIO);
2604
2605 /*
2606 * If the I/O failed, determine whether we should attempt to retry it.
2607 *
2608 * On retry, we cut in line in the issue queue, since we don't want
2609 * compression/checksumming/etc. work to prevent our (cheap) IO reissue.
2610 */
2611 if (zio->io_error && vd == NULL &&
2612 !(zio->io_flags & (ZIO_FLAG_DONT_RETRY | ZIO_FLAG_IO_RETRY))) {
2613 ASSERT(!(zio->io_flags & ZIO_FLAG_DONT_QUEUE)); /* not a leaf */
2614 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_BYPASS)); /* not a leaf */
2615 zio->io_error = 0;
2616 zio->io_flags |= ZIO_FLAG_IO_RETRY |
2617 ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE;
2618 zio->io_stage = ZIO_STAGE_VDEV_IO_START >> 1;
2619 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE,
2620 zio_requeue_io_start_cut_in_line);
2621 return (ZIO_PIPELINE_STOP);
2622 }
2623
2624 /*
2625 * If we got an error on a leaf device, convert it to ENXIO
2626 * if the device is not accessible at all.
2627 */
2628 if (zio->io_error && vd != NULL && vd->vdev_ops->vdev_op_leaf &&
2629 !vdev_accessible(vd, zio))
2630 zio->io_error = SET_ERROR(ENXIO);
2631
2632 /*
2633 * If we can't write to an interior vdev (mirror or RAID-Z),
2634 * set vdev_cant_write so that we stop trying to allocate from it.
2635 */
2636 if (zio->io_error == ENXIO && zio->io_type == ZIO_TYPE_WRITE &&
2637 vd != NULL && !vd->vdev_ops->vdev_op_leaf) {
2638 vd->vdev_cant_write = B_TRUE;
2639 }
2640
2641 if (zio->io_error)
2642 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
2643
2644 if (vd != NULL && vd->vdev_ops->vdev_op_leaf &&
2645 zio->io_physdone != NULL) {
2646 ASSERT(!(zio->io_flags & ZIO_FLAG_DELEGATED));
2647 ASSERT(zio->io_child_type == ZIO_CHILD_VDEV);
2648 zio->io_physdone(zio->io_logical);
2649 }
2650
2651 return (ZIO_PIPELINE_CONTINUE);
2652 }
2653
2654 void
2655 zio_vdev_io_reissue(zio_t *zio)
2656 {
2657 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START);
2658 ASSERT(zio->io_error == 0);
2659
2660 zio->io_stage >>= 1;
2661 }
2662
2663 void
2664 zio_vdev_io_redone(zio_t *zio)
2665 {
2666 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_DONE);
2667
2668 zio->io_stage >>= 1;
2669 }
2670
2671 void
2672 zio_vdev_io_bypass(zio_t *zio)
2673 {
2674 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START);
2675 ASSERT(zio->io_error == 0);
2676
2677 zio->io_flags |= ZIO_FLAG_IO_BYPASS;
2678 zio->io_stage = ZIO_STAGE_VDEV_IO_ASSESS >> 1;
2679 }
2680
2681 /*
2682 * ==========================================================================
2683 * Generate and verify checksums
2684 * ==========================================================================
2685 */
2686 static int
2687 zio_checksum_generate(zio_t *zio)
2688 {
2689 blkptr_t *bp = zio->io_bp;
2690 enum zio_checksum checksum;
2691
2692 if (bp == NULL) {
2693 /*
2694 * This is zio_write_phys().
2695 * We're either generating a label checksum, or none at all.
2696 */
2697 checksum = zio->io_prop.zp_checksum;
2698
2699 if (checksum == ZIO_CHECKSUM_OFF)
2700 return (ZIO_PIPELINE_CONTINUE);
2701
2702 ASSERT(checksum == ZIO_CHECKSUM_LABEL);
2703 } else {
2704 if (BP_IS_GANG(bp) && zio->io_child_type == ZIO_CHILD_GANG) {
2705 ASSERT(!IO_IS_ALLOCATING(zio));
2706 checksum = ZIO_CHECKSUM_GANG_HEADER;
2707 } else {
2708 checksum = BP_GET_CHECKSUM(bp);
2709 }
2710 }
2711
2712 zio_checksum_compute(zio, checksum, zio->io_data, zio->io_size);
2713
2714 return (ZIO_PIPELINE_CONTINUE);
2715 }
2716
2717 static int
2718 zio_checksum_verify(zio_t *zio)
2719 {
2720 zio_bad_cksum_t info;
2721 blkptr_t *bp = zio->io_bp;
2722 int error;
2723
2724 ASSERT(zio->io_vd != NULL);
2725
2726 if (bp == NULL) {
2727 /*
2728 * This is zio_read_phys().
2729 * We're either verifying a label checksum, or nothing at all.
2730 */
2731 if (zio->io_prop.zp_checksum == ZIO_CHECKSUM_OFF)
2732 return (ZIO_PIPELINE_CONTINUE);
2733
2734 ASSERT(zio->io_prop.zp_checksum == ZIO_CHECKSUM_LABEL);
2735 }
2736
2737 if ((error = zio_checksum_error(zio, &info)) != 0) {
2738 zio->io_error = error;
2739 if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) {
2740 zfs_ereport_start_checksum(zio->io_spa,
2741 zio->io_vd, zio, zio->io_offset,
2742 zio->io_size, NULL, &info);
2743 }
2744 }
2745
2746 return (ZIO_PIPELINE_CONTINUE);
2747 }
2748
2749 /*
2750 * Called by RAID-Z to ensure we don't compute the checksum twice.
2751 */
2752 void
2753 zio_checksum_verified(zio_t *zio)
2754 {
2755 zio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY;
2756 }
2757
2758 /*
2759 * ==========================================================================
2760 * Error rank. Error are ranked in the order 0, ENXIO, ECKSUM, EIO, other.
2761 * An error of 0 indictes success. ENXIO indicates whole-device failure,
2762 * which may be transient (e.g. unplugged) or permament. ECKSUM and EIO
2763 * indicate errors that are specific to one I/O, and most likely permanent.
2764 * Any other error is presumed to be worse because we weren't expecting it.
2765 * ==========================================================================
2766 */
2767 int
2768 zio_worst_error(int e1, int e2)
2769 {
2770 static int zio_error_rank[] = { 0, ENXIO, ECKSUM, EIO };
2771 int r1, r2;
2772
2773 for (r1 = 0; r1 < sizeof (zio_error_rank) / sizeof (int); r1++)
2774 if (e1 == zio_error_rank[r1])
2775 break;
2776
2777 for (r2 = 0; r2 < sizeof (zio_error_rank) / sizeof (int); r2++)
2778 if (e2 == zio_error_rank[r2])
2779 break;
2780
2781 return (r1 > r2 ? e1 : e2);
2782 }
2783
2784 /*
2785 * ==========================================================================
2786 * I/O completion
2787 * ==========================================================================
2788 */
2789 static int
2790 zio_ready(zio_t *zio)
2791 {
2792 blkptr_t *bp = zio->io_bp;
2793 zio_t *pio, *pio_next;
2794
2795 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) ||
2796 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_READY))
2797 return (ZIO_PIPELINE_STOP);
2798
2799 if (zio->io_ready) {
2800 ASSERT(IO_IS_ALLOCATING(zio));
2801 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp) ||
2802 (zio->io_flags & ZIO_FLAG_NOPWRITE));
2803 ASSERT(zio->io_children[ZIO_CHILD_GANG][ZIO_WAIT_READY] == 0);
2804
2805 zio->io_ready(zio);
2806 }
2807
2808 if (bp != NULL && bp != &zio->io_bp_copy)
2809 zio->io_bp_copy = *bp;
2810
2811 if (zio->io_error)
2812 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
2813
2814 mutex_enter(&zio->io_lock);
2815 zio->io_state[ZIO_WAIT_READY] = 1;
2816 pio = zio_walk_parents(zio);
2817 mutex_exit(&zio->io_lock);
2818
2819 /*
2820 * As we notify zio's parents, new parents could be added.
2821 * New parents go to the head of zio's io_parent_list, however,
2822 * so we will (correctly) not notify them. The remainder of zio's
2823 * io_parent_list, from 'pio_next' onward, cannot change because
2824 * all parents must wait for us to be done before they can be done.
2825 */
2826 for (; pio != NULL; pio = pio_next) {
2827 pio_next = zio_walk_parents(zio);
2828 zio_notify_parent(pio, zio, ZIO_WAIT_READY);
2829 }
2830
2831 if (zio->io_flags & ZIO_FLAG_NODATA) {
2832 if (BP_IS_GANG(bp)) {
2833 zio->io_flags &= ~ZIO_FLAG_NODATA;
2834 } else {
2835 ASSERT((uintptr_t)zio->io_data < SPA_MAXBLOCKSIZE);
2836 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES;
2837 }
2838 }
2839
2840 if (zio_injection_enabled &&
2841 zio->io_spa->spa_syncing_txg == zio->io_txg)
2842 zio_handle_ignored_writes(zio);
2843
2844 return (ZIO_PIPELINE_CONTINUE);
2845 }
2846
2847 static int
2848 zio_done(zio_t *zio)
2849 {
2850 spa_t *spa = zio->io_spa;
2851 zio_t *lio = zio->io_logical;
2852 blkptr_t *bp = zio->io_bp;
2853 vdev_t *vd = zio->io_vd;
2854 uint64_t psize = zio->io_size;
2855 zio_t *pio, *pio_next;
2856
2857 /*
2858 * If our children haven't all completed,
2859 * wait for them and then repeat this pipeline stage.
2860 */
2861 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE) ||
2862 zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE) ||
2863 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE) ||
2864 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_DONE))
2865 return (ZIO_PIPELINE_STOP);
2866
2867 for (int c = 0; c < ZIO_CHILD_TYPES; c++)
2868 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
2869 ASSERT(zio->io_children[c][w] == 0);
2870
2871 if (bp != NULL) {
2872 ASSERT(bp->blk_pad[0] == 0);
2873 ASSERT(bp->blk_pad[1] == 0);
2874 ASSERT(bcmp(bp, &zio->io_bp_copy, sizeof (blkptr_t)) == 0 ||
2875 (bp == zio_unique_parent(zio)->io_bp));
2876 if (zio->io_type == ZIO_TYPE_WRITE && !BP_IS_HOLE(bp) &&
2877 zio->io_bp_override == NULL &&
2878 !(zio->io_flags & ZIO_FLAG_IO_REPAIR)) {
2879 ASSERT(!BP_SHOULD_BYTESWAP(bp));
2880 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(bp));
2881 ASSERT(BP_COUNT_GANG(bp) == 0 ||
2882 (BP_COUNT_GANG(bp) == BP_GET_NDVAS(bp)));
2883 }
2884 if (zio->io_flags & ZIO_FLAG_NOPWRITE)
2885 VERIFY(BP_EQUAL(bp, &zio->io_bp_orig));
2886 }
2887
2888 /*
2889 * If there were child vdev/gang/ddt errors, they apply to us now.
2890 */
2891 zio_inherit_child_errors(zio, ZIO_CHILD_VDEV);
2892 zio_inherit_child_errors(zio, ZIO_CHILD_GANG);
2893 zio_inherit_child_errors(zio, ZIO_CHILD_DDT);
2894
2895 /*
2896 * If the I/O on the transformed data was successful, generate any
2897 * checksum reports now while we still have the transformed data.
2898 */
2899 if (zio->io_error == 0) {
2900 while (zio->io_cksum_report != NULL) {
2901 zio_cksum_report_t *zcr = zio->io_cksum_report;
2902 uint64_t align = zcr->zcr_align;
2903 uint64_t asize = P2ROUNDUP(psize, align);
2904 char *abuf = zio->io_data;
2905
2906 if (asize != psize) {
2907 abuf = zio_buf_alloc(asize);
2908 bcopy(zio->io_data, abuf, psize);
2909 bzero(abuf + psize, asize - psize);
2910 }
2911
2912 zio->io_cksum_report = zcr->zcr_next;
2913 zcr->zcr_next = NULL;
2914 zcr->zcr_finish(zcr, abuf);
2915 zfs_ereport_free_checksum(zcr);
2916
2917 if (asize != psize)
2918 zio_buf_free(abuf, asize);
2919 }
2920 }
2921
2922 zio_pop_transforms(zio); /* note: may set zio->io_error */
2923
2924 vdev_stat_update(zio, psize);
2925
2926 if (zio->io_error) {
2927 /*
2928 * If this I/O is attached to a particular vdev,
2929 * generate an error message describing the I/O failure
2930 * at the block level. We ignore these errors if the
2931 * device is currently unavailable.
2932 */
2933 if (zio->io_error != ECKSUM && vd != NULL && !vdev_is_dead(vd))
2934 zfs_ereport_post(FM_EREPORT_ZFS_IO, spa, vd, zio, 0, 0);
2935
2936 if ((zio->io_error == EIO || !(zio->io_flags &
2937 (ZIO_FLAG_SPECULATIVE | ZIO_FLAG_DONT_PROPAGATE))) &&
2938 zio == lio) {
2939 /*
2940 * For logical I/O requests, tell the SPA to log the
2941 * error and generate a logical data ereport.
2942 */
2943 spa_log_error(spa, zio);
2944 zfs_ereport_post(FM_EREPORT_ZFS_DATA, spa, NULL, zio,
2945 0, 0);
2946 }
2947 }
2948
2949 if (zio->io_error && zio == lio) {
2950 /*
2951 * Determine whether zio should be reexecuted. This will
2952 * propagate all the way to the root via zio_notify_parent().
2953 */
2954 ASSERT(vd == NULL && bp != NULL);
2955 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
2956
2957 if (IO_IS_ALLOCATING(zio) &&
2958 !(zio->io_flags & ZIO_FLAG_CANFAIL)) {
2959 if (zio->io_error != ENOSPC)
2960 zio->io_reexecute |= ZIO_REEXECUTE_NOW;
2961 else
2962 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
2963 }
2964
2965 if ((zio->io_type == ZIO_TYPE_READ ||
2966 zio->io_type == ZIO_TYPE_FREE) &&
2967 !(zio->io_flags & ZIO_FLAG_SCAN_THREAD) &&
2968 zio->io_error == ENXIO &&
2969 spa_load_state(spa) == SPA_LOAD_NONE &&
2970 spa_get_failmode(spa) != ZIO_FAILURE_MODE_CONTINUE)
2971 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
2972
2973 if (!(zio->io_flags & ZIO_FLAG_CANFAIL) && !zio->io_reexecute)
2974 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
2975
2976 /*
2977 * Here is a possibly good place to attempt to do
2978 * either combinatorial reconstruction or error correction
2979 * based on checksums. It also might be a good place
2980 * to send out preliminary ereports before we suspend
2981 * processing.
2982 */
2983 }
2984
2985 /*
2986 * If there were logical child errors, they apply to us now.
2987 * We defer this until now to avoid conflating logical child
2988 * errors with errors that happened to the zio itself when
2989 * updating vdev stats and reporting FMA events above.
2990 */
2991 zio_inherit_child_errors(zio, ZIO_CHILD_LOGICAL);
2992
2993 if ((zio->io_error || zio->io_reexecute) &&
2994 IO_IS_ALLOCATING(zio) && zio->io_gang_leader == zio &&
2995 !(zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)))
2996 zio_dva_unallocate(zio, zio->io_gang_tree, bp);
2997
2998 zio_gang_tree_free(&zio->io_gang_tree);
2999
3000 /*
3001 * Godfather I/Os should never suspend.
3002 */
3003 if ((zio->io_flags & ZIO_FLAG_GODFATHER) &&
3004 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND))
3005 zio->io_reexecute = 0;
3006
3007 if (zio->io_reexecute) {
3008 /*
3009 * This is a logical I/O that wants to reexecute.
3010 *
3011 * Reexecute is top-down. When an i/o fails, if it's not
3012 * the root, it simply notifies its parent and sticks around.
3013 * The parent, seeing that it still has children in zio_done(),
3014 * does the same. This percolates all the way up to the root.
3015 * The root i/o will reexecute or suspend the entire tree.
3016 *
3017 * This approach ensures that zio_reexecute() honors
3018 * all the original i/o dependency relationships, e.g.
3019 * parents not executing until children are ready.
3020 */
3021 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
3022
3023 zio->io_gang_leader = NULL;
3024
3025 mutex_enter(&zio->io_lock);
3026 zio->io_state[ZIO_WAIT_DONE] = 1;
3027 mutex_exit(&zio->io_lock);
3028
3029 /*
3030 * "The Godfather" I/O monitors its children but is
3031 * not a true parent to them. It will track them through
3032 * the pipeline but severs its ties whenever they get into
3033 * trouble (e.g. suspended). This allows "The Godfather"
3034 * I/O to return status without blocking.
3035 */
3036 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) {
3037 zio_link_t *zl = zio->io_walk_link;
3038 pio_next = zio_walk_parents(zio);
3039
3040 if ((pio->io_flags & ZIO_FLAG_GODFATHER) &&
3041 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND)) {
3042 zio_remove_child(pio, zio, zl);
3043 zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
3044 }
3045 }
3046
3047 if ((pio = zio_unique_parent(zio)) != NULL) {
3048 /*
3049 * We're not a root i/o, so there's nothing to do
3050 * but notify our parent. Don't propagate errors
3051 * upward since we haven't permanently failed yet.
3052 */
3053 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER));
3054 zio->io_flags |= ZIO_FLAG_DONT_PROPAGATE;
3055 zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
3056 } else if (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND) {
3057 /*
3058 * We'd fail again if we reexecuted now, so suspend
3059 * until conditions improve (e.g. device comes online).
3060 */
3061 zio_suspend(spa, zio);
3062 } else {
3063 /*
3064 * Reexecution is potentially a huge amount of work.
3065 * Hand it off to the otherwise-unused claim taskq.
3066 */
3067 ASSERT(zio->io_tqent.tqent_next == NULL);
3068 spa_taskq_dispatch_ent(spa, ZIO_TYPE_CLAIM,
3069 ZIO_TASKQ_ISSUE, (task_func_t *)zio_reexecute, zio,
3070 0, &zio->io_tqent);
3071 }
3072 return (ZIO_PIPELINE_STOP);
3073 }
3074
3075 ASSERT(zio->io_child_count == 0);
3076 ASSERT(zio->io_reexecute == 0);
3077 ASSERT(zio->io_error == 0 || (zio->io_flags & ZIO_FLAG_CANFAIL));
3078
3079 /*
3080 * Report any checksum errors, since the I/O is complete.
3081 */
3082 while (zio->io_cksum_report != NULL) {
3083 zio_cksum_report_t *zcr = zio->io_cksum_report;
3084 zio->io_cksum_report = zcr->zcr_next;
3085 zcr->zcr_next = NULL;
3086 zcr->zcr_finish(zcr, NULL);
3087 zfs_ereport_free_checksum(zcr);
3088 }
3089
3090 /*
3091 * It is the responsibility of the done callback to ensure that this
3092 * particular zio is no longer discoverable for adoption, and as
3093 * such, cannot acquire any new parents.
3094 */
3095 if (zio->io_done)
3096 zio->io_done(zio);
3097
3098 mutex_enter(&zio->io_lock);
3099 zio->io_state[ZIO_WAIT_DONE] = 1;
3100 mutex_exit(&zio->io_lock);
3101
3102 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) {
3103 zio_link_t *zl = zio->io_walk_link;
3104 pio_next = zio_walk_parents(zio);
3105 zio_remove_child(pio, zio, zl);
3106 zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
3107 }
3108
3109 if (zio->io_waiter != NULL) {
3110 mutex_enter(&zio->io_lock);
3111 zio->io_executor = NULL;
3112 cv_broadcast(&zio->io_cv);
3113 mutex_exit(&zio->io_lock);
3114 } else {
3115 zio_destroy(zio);
3116 }
3117
3118 return (ZIO_PIPELINE_STOP);
3119 }
3120
3121 /*
3122 * ==========================================================================
3123 * I/O pipeline definition
3124 * ==========================================================================
3125 */
3126 static zio_pipe_stage_t *zio_pipeline[] = {
3127 NULL,
3128 zio_read_bp_init,
3129 zio_free_bp_init,
3130 zio_issue_async,
3131 zio_write_bp_init,
3132 zio_checksum_generate,
3133 zio_nop_write,
3134 zio_ddt_read_start,
3135 zio_ddt_read_done,
3136 zio_ddt_write,
3137 zio_ddt_free,
3138 zio_gang_assemble,
3139 zio_gang_issue,
3140 zio_dva_allocate,
3141 zio_dva_free,
3142 zio_dva_claim,
3143 zio_ready,
3144 zio_vdev_io_start,
3145 zio_vdev_io_done,
3146 zio_vdev_io_assess,
3147 zio_checksum_verify,
3148 zio_done
3149 };
3150
3151 /* dnp is the dnode for zb1->zb_object */
3152 boolean_t
3153 zbookmark_is_before(const dnode_phys_t *dnp, const zbookmark_t *zb1,
3154 const zbookmark_t *zb2)
3155 {
3156 uint64_t zb1nextL0, zb2thisobj;
3157
3158 ASSERT(zb1->zb_objset == zb2->zb_objset);
3159 ASSERT(zb2->zb_level == 0);
3160
3161 /*
3162 * A bookmark in the deadlist is considered to be after
3163 * everything else.
3164 */
3165 if (zb2->zb_object == DMU_DEADLIST_OBJECT)
3166 return (B_TRUE);
3167
3168 /* The objset_phys_t isn't before anything. */
3169 if (dnp == NULL)
3170 return (B_FALSE);
3171
3172 zb1nextL0 = (zb1->zb_blkid + 1) <<
3173 ((zb1->zb_level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT));
3174
3175 zb2thisobj = zb2->zb_object ? zb2->zb_object :
3176 zb2->zb_blkid << (DNODE_BLOCK_SHIFT - DNODE_SHIFT);
3177
3178 if (zb1->zb_object == DMU_META_DNODE_OBJECT) {
3179 uint64_t nextobj = zb1nextL0 *
3180 (dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT) >> DNODE_SHIFT;
3181 return (nextobj <= zb2thisobj);
3182 }
3183
3184 if (zb1->zb_object < zb2thisobj)
3185 return (B_TRUE);
3186 if (zb1->zb_object > zb2thisobj)
3187 return (B_FALSE);
3188 if (zb2->zb_object == DMU_META_DNODE_OBJECT)
3189 return (B_FALSE);
3190 return (zb1nextL0 <= zb2->zb_blkid);
3191 }