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) 2012 by Delphix. All rights reserved.
24 * Copyright (c) 2011 Nexenta Systems, Inc. All rights reserved.
25 */
26
27 #include <sys/zfs_context.h>
28 #include <sys/fm/fs/zfs.h>
29 #include <sys/spa.h>
30 #include <sys/txg.h>
31 #include <sys/spa_impl.h>
32 #include <sys/vdev_impl.h>
33 #include <sys/zio_impl.h>
34 #include <sys/zio_compress.h>
35 #include <sys/zio_checksum.h>
36 #include <sys/dmu_objset.h>
37 #include <sys/arc.h>
38 #include <sys/ddt.h>
39
40 /*
41 * ==========================================================================
42 * I/O priority table
43 * ==========================================================================
44 */
45 uint8_t zio_priority_table[ZIO_PRIORITY_TABLE_SIZE] = {
46 0, /* ZIO_PRIORITY_NOW */
47 0, /* ZIO_PRIORITY_SYNC_READ */
48 0, /* ZIO_PRIORITY_SYNC_WRITE */
49 0, /* ZIO_PRIORITY_LOG_WRITE */
50 1, /* ZIO_PRIORITY_CACHE_FILL */
51 1, /* ZIO_PRIORITY_AGG */
52 4, /* ZIO_PRIORITY_FREE */
53 4, /* ZIO_PRIORITY_ASYNC_WRITE */
54 6, /* ZIO_PRIORITY_ASYNC_READ */
55 10, /* ZIO_PRIORITY_RESILVER */
56 20, /* ZIO_PRIORITY_SCRUB */
57 2, /* ZIO_PRIORITY_DDT_PREFETCH */
58 };
59
60 /*
61 * ==========================================================================
62 * I/O type descriptions
63 * ==========================================================================
64 */
65 char *zio_type_name[ZIO_TYPES] = {
66 "zio_null", "zio_read", "zio_write", "zio_free", "zio_claim",
67 "zio_ioctl"
68 };
69
70 /*
71 * ==========================================================================
72 * I/O kmem caches
73 * ==========================================================================
74 */
75 kmem_cache_t *zio_cache;
76 kmem_cache_t *zio_link_cache;
77 kmem_cache_t *zio_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
78 kmem_cache_t *zio_data_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
79
80 #ifdef _KERNEL
81 extern vmem_t *zio_alloc_arena;
82 #endif
83 extern int zfs_mg_alloc_failures;
84
85 /*
86 * An allocating zio is one that either currently has the DVA allocate
87 * stage set or will have it later in its lifetime.
88 */
89 #define IO_IS_ALLOCATING(zio) ((zio)->io_orig_pipeline & ZIO_STAGE_DVA_ALLOCATE)
90
91 boolean_t zio_requeue_io_start_cut_in_line = B_TRUE;
92
93 #ifdef ZFS_DEBUG
94 int zio_buf_debug_limit = 16384;
95 #else
96 int zio_buf_debug_limit = 0;
97 #endif
98
99 void
100 zio_init(void)
101 {
102 size_t c;
103 vmem_t *data_alloc_arena = NULL;
104
105 #ifdef _KERNEL
106 data_alloc_arena = zio_alloc_arena;
107 #endif
108 zio_cache = kmem_cache_create("zio_cache",
109 sizeof (zio_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
110 zio_link_cache = kmem_cache_create("zio_link_cache",
111 sizeof (zio_link_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
112
113 /*
114 * For small buffers, we want a cache for each multiple of
115 * SPA_MINBLOCKSIZE. For medium-size buffers, we want a cache
116 * for each quarter-power of 2. For large buffers, we want
117 * a cache for each multiple of PAGESIZE.
118 */
119 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) {
120 size_t size = (c + 1) << SPA_MINBLOCKSHIFT;
121 size_t p2 = size;
122 size_t align = 0;
123 size_t cflags = (size > zio_buf_debug_limit) ? KMC_NODEBUG : 0;
124
125 while (p2 & (p2 - 1))
126 p2 &= p2 - 1;
127
128 if (size <= 4 * SPA_MINBLOCKSIZE) {
129 align = SPA_MINBLOCKSIZE;
130 } else if (P2PHASE(size, PAGESIZE) == 0) {
131 align = PAGESIZE;
132 } else if (P2PHASE(size, p2 >> 2) == 0) {
133 align = p2 >> 2;
134 }
135
136 if (align != 0) {
137 char name[36];
138 (void) sprintf(name, "zio_buf_%lu", (ulong_t)size);
139 zio_buf_cache[c] = kmem_cache_create(name, size,
140 align, NULL, NULL, NULL, NULL, NULL, cflags);
141
142 /*
143 * Since zio_data bufs do not appear in crash dumps, we
144 * pass KMC_NOTOUCH so that no allocator metadata is
145 * stored with the buffers.
146 */
147 (void) sprintf(name, "zio_data_buf_%lu", (ulong_t)size);
148 zio_data_buf_cache[c] = kmem_cache_create(name, size,
149 align, NULL, NULL, NULL, NULL, data_alloc_arena,
150 cflags | KMC_NOTOUCH);
151 }
152 }
153
154 while (--c != 0) {
155 ASSERT(zio_buf_cache[c] != NULL);
156 if (zio_buf_cache[c - 1] == NULL)
157 zio_buf_cache[c - 1] = zio_buf_cache[c];
158
159 ASSERT(zio_data_buf_cache[c] != NULL);
160 if (zio_data_buf_cache[c - 1] == NULL)
161 zio_data_buf_cache[c - 1] = zio_data_buf_cache[c];
162 }
163
164 /*
165 * The zio write taskqs have 1 thread per cpu, allow 1/2 of the taskqs
166 * to fail 3 times per txg or 8 failures, whichever is greater.
167 */
168 zfs_mg_alloc_failures = MAX((3 * max_ncpus / 2), 8);
169
170 zio_inject_init();
171 }
172
173 void
174 zio_fini(void)
175 {
176 size_t c;
177 kmem_cache_t *last_cache = NULL;
178 kmem_cache_t *last_data_cache = NULL;
179
180 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) {
181 if (zio_buf_cache[c] != last_cache) {
182 last_cache = zio_buf_cache[c];
183 kmem_cache_destroy(zio_buf_cache[c]);
184 }
185 zio_buf_cache[c] = NULL;
186
187 if (zio_data_buf_cache[c] != last_data_cache) {
188 last_data_cache = zio_data_buf_cache[c];
189 kmem_cache_destroy(zio_data_buf_cache[c]);
190 }
191 zio_data_buf_cache[c] = NULL;
192 }
193
194 kmem_cache_destroy(zio_link_cache);
195 kmem_cache_destroy(zio_cache);
196
197 zio_inject_fini();
198 }
199
200 /*
201 * ==========================================================================
202 * Allocate and free I/O buffers
203 * ==========================================================================
204 */
205
206 /*
207 * Use zio_buf_alloc to allocate ZFS metadata. This data will appear in a
208 * crashdump if the kernel panics, so use it judiciously. Obviously, it's
209 * useful to inspect ZFS metadata, but if possible, we should avoid keeping
210 * excess / transient data in-core during a crashdump.
211 */
212 void *
213 zio_buf_alloc(size_t size)
214 {
215 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
216
217 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
218
219 return (kmem_cache_alloc(zio_buf_cache[c], KM_PUSHPAGE));
220 }
221
222 /*
223 * Use zio_data_buf_alloc to allocate data. The data will not appear in a
224 * crashdump if the kernel panics. This exists so that we will limit the amount
225 * of ZFS data that shows up in a kernel crashdump. (Thus reducing the amount
226 * of kernel heap dumped to disk when the kernel panics)
227 */
228 void *
229 zio_data_buf_alloc(size_t size)
230 {
231 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
232
233 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
234
235 return (kmem_cache_alloc(zio_data_buf_cache[c], KM_PUSHPAGE));
236 }
237
238 void
239 zio_buf_free(void *buf, size_t size)
240 {
241 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
242
243 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
244
245 kmem_cache_free(zio_buf_cache[c], buf);
246 }
247
248 void
249 zio_data_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_data_buf_cache[c], buf);
256 }
257
258 /*
259 * ==========================================================================
260 * Push and pop I/O transform buffers
261 * ==========================================================================
262 */
263 static void
264 zio_push_transform(zio_t *zio, void *data, uint64_t size, uint64_t bufsize,
265 zio_transform_func_t *transform)
266 {
267 zio_transform_t *zt = kmem_alloc(sizeof (zio_transform_t), KM_SLEEP);
268
269 zt->zt_orig_data = zio->io_data;
270 zt->zt_orig_size = zio->io_size;
271 zt->zt_bufsize = bufsize;
272 zt->zt_transform = transform;
273
274 zt->zt_next = zio->io_transform_stack;
275 zio->io_transform_stack = zt;
276
277 zio->io_data = data;
278 zio->io_size = size;
279 }
280
281 static void
282 zio_pop_transforms(zio_t *zio)
283 {
284 zio_transform_t *zt;
285
286 while ((zt = zio->io_transform_stack) != NULL) {
287 if (zt->zt_transform != NULL)
288 zt->zt_transform(zio,
289 zt->zt_orig_data, zt->zt_orig_size);
290
291 if (zt->zt_bufsize != 0)
292 zio_buf_free(zio->io_data, zt->zt_bufsize);
293
294 zio->io_data = zt->zt_orig_data;
295 zio->io_size = zt->zt_orig_size;
296 zio->io_transform_stack = zt->zt_next;
297
298 kmem_free(zt, sizeof (zio_transform_t));
299 }
300 }
301
302 /*
303 * ==========================================================================
304 * I/O transform callbacks for subblocks and decompression
305 * ==========================================================================
306 */
307 static void
308 zio_subblock(zio_t *zio, void *data, uint64_t size)
309 {
310 ASSERT(zio->io_size > size);
311
312 if (zio->io_type == ZIO_TYPE_READ)
313 bcopy(zio->io_data, data, size);
314 }
315
316 static void
317 zio_decompress(zio_t *zio, void *data, uint64_t size)
318 {
319 if (zio->io_error == 0 &&
320 zio_decompress_data(BP_GET_COMPRESS(zio->io_bp),
321 zio->io_data, data, zio->io_size, size) != 0)
322 zio->io_error = EIO;
323 }
324
325 /*
326 * ==========================================================================
327 * I/O parent/child relationships and pipeline interlocks
328 * ==========================================================================
329 */
330 /*
331 * NOTE - Callers to zio_walk_parents() and zio_walk_children must
332 * continue calling these functions until they return NULL.
333 * Otherwise, the next caller will pick up the list walk in
334 * some indeterminate state. (Otherwise every caller would
335 * have to pass in a cookie to keep the state represented by
336 * io_walk_link, which gets annoying.)
337 */
338 zio_t *
339 zio_walk_parents(zio_t *cio)
340 {
341 zio_link_t *zl = cio->io_walk_link;
342 list_t *pl = &cio->io_parent_list;
343
344 zl = (zl == NULL) ? list_head(pl) : list_next(pl, zl);
345 cio->io_walk_link = zl;
346
347 if (zl == NULL)
348 return (NULL);
349
350 ASSERT(zl->zl_child == cio);
351 return (zl->zl_parent);
352 }
353
354 zio_t *
355 zio_walk_children(zio_t *pio)
356 {
357 zio_link_t *zl = pio->io_walk_link;
358 list_t *cl = &pio->io_child_list;
359
360 zl = (zl == NULL) ? list_head(cl) : list_next(cl, zl);
361 pio->io_walk_link = zl;
362
363 if (zl == NULL)
364 return (NULL);
365
366 ASSERT(zl->zl_parent == pio);
367 return (zl->zl_child);
368 }
369
370 zio_t *
371 zio_unique_parent(zio_t *cio)
372 {
373 zio_t *pio = zio_walk_parents(cio);
374
375 VERIFY(zio_walk_parents(cio) == NULL);
376 return (pio);
377 }
378
379 void
380 zio_add_child(zio_t *pio, zio_t *cio)
381 {
382 zio_link_t *zl = kmem_cache_alloc(zio_link_cache, KM_SLEEP);
383
384 /*
385 * Logical I/Os can have logical, gang, or vdev children.
386 * Gang I/Os can have gang or vdev children.
387 * Vdev I/Os can only have vdev children.
388 * The following ASSERT captures all of these constraints.
389 */
390 ASSERT(cio->io_child_type <= pio->io_child_type);
391
392 zl->zl_parent = pio;
393 zl->zl_child = cio;
394
395 mutex_enter(&cio->io_lock);
396 mutex_enter(&pio->io_lock);
397
398 ASSERT(pio->io_state[ZIO_WAIT_DONE] == 0);
399
400 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
401 pio->io_children[cio->io_child_type][w] += !cio->io_state[w];
402
403 list_insert_head(&pio->io_child_list, zl);
404 list_insert_head(&cio->io_parent_list, zl);
405
406 pio->io_child_count++;
407 cio->io_parent_count++;
408
409 mutex_exit(&pio->io_lock);
410 mutex_exit(&cio->io_lock);
411 }
412
413 static void
414 zio_remove_child(zio_t *pio, zio_t *cio, zio_link_t *zl)
415 {
416 ASSERT(zl->zl_parent == pio);
417 ASSERT(zl->zl_child == cio);
418
419 mutex_enter(&cio->io_lock);
420 mutex_enter(&pio->io_lock);
421
422 list_remove(&pio->io_child_list, zl);
423 list_remove(&cio->io_parent_list, zl);
424
425 pio->io_child_count--;
426 cio->io_parent_count--;
427
428 mutex_exit(&pio->io_lock);
429 mutex_exit(&cio->io_lock);
430
431 kmem_cache_free(zio_link_cache, zl);
432 }
433
434 static boolean_t
435 zio_wait_for_children(zio_t *zio, enum zio_child child, enum zio_wait_type wait)
436 {
437 uint64_t *countp = &zio->io_children[child][wait];
438 boolean_t waiting = B_FALSE;
439
440 mutex_enter(&zio->io_lock);
441 ASSERT(zio->io_stall == NULL);
442 if (*countp != 0) {
443 zio->io_stage >>= 1;
444 zio->io_stall = countp;
445 waiting = B_TRUE;
446 }
447 mutex_exit(&zio->io_lock);
448
449 return (waiting);
450 }
451
452 static void
453 zio_notify_parent(zio_t *pio, zio_t *zio, enum zio_wait_type wait)
454 {
455 uint64_t *countp = &pio->io_children[zio->io_child_type][wait];
456 int *errorp = &pio->io_child_error[zio->io_child_type];
457
458 mutex_enter(&pio->io_lock);
459 if (zio->io_error && !(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE))
460 *errorp = zio_worst_error(*errorp, zio->io_error);
461 pio->io_reexecute |= zio->io_reexecute;
462 ASSERT3U(*countp, >, 0);
463 if (--*countp == 0 && pio->io_stall == countp) {
464 pio->io_stall = NULL;
465 mutex_exit(&pio->io_lock);
466 zio_execute(pio);
467 } else {
468 mutex_exit(&pio->io_lock);
469 }
470 }
471
472 static void
473 zio_inherit_child_errors(zio_t *zio, enum zio_child c)
474 {
475 if (zio->io_child_error[c] != 0 && zio->io_error == 0)
476 zio->io_error = zio->io_child_error[c];
477 }
478
479 /*
480 * ==========================================================================
481 * Create the various types of I/O (read, write, free, etc)
482 * ==========================================================================
483 */
484 static zio_t *
485 zio_create(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
486 void *data, uint64_t size, zio_done_func_t *done, void *private,
487 zio_type_t type, int priority, enum zio_flag flags,
488 vdev_t *vd, uint64_t offset, const zbookmark_t *zb,
489 enum zio_stage stage, enum zio_stage pipeline)
490 {
491 zio_t *zio;
492
493 ASSERT3U(size, <=, SPA_MAXBLOCKSIZE);
494 ASSERT(P2PHASE(size, SPA_MINBLOCKSIZE) == 0);
495 ASSERT(P2PHASE(offset, SPA_MINBLOCKSIZE) == 0);
496
497 ASSERT(!vd || spa_config_held(spa, SCL_STATE_ALL, RW_READER));
498 ASSERT(!bp || !(flags & ZIO_FLAG_CONFIG_WRITER));
499 ASSERT(vd || stage == ZIO_STAGE_OPEN);
500
501 zio = kmem_cache_alloc(zio_cache, KM_SLEEP);
502 bzero(zio, sizeof (zio_t));
503
504 mutex_init(&zio->io_lock, NULL, MUTEX_DEFAULT, NULL);
505 cv_init(&zio->io_cv, NULL, CV_DEFAULT, NULL);
506
507 list_create(&zio->io_parent_list, sizeof (zio_link_t),
508 offsetof(zio_link_t, zl_parent_node));
509 list_create(&zio->io_child_list, sizeof (zio_link_t),
510 offsetof(zio_link_t, zl_child_node));
511
512 if (vd != NULL)
513 zio->io_child_type = ZIO_CHILD_VDEV;
514 else if (flags & ZIO_FLAG_GANG_CHILD)
515 zio->io_child_type = ZIO_CHILD_GANG;
516 else if (flags & ZIO_FLAG_DDT_CHILD)
517 zio->io_child_type = ZIO_CHILD_DDT;
518 else
519 zio->io_child_type = ZIO_CHILD_LOGICAL;
520
521 if (bp != NULL) {
522 zio->io_bp = (blkptr_t *)bp;
523 zio->io_bp_copy = *bp;
524 zio->io_bp_orig = *bp;
525 if (type != ZIO_TYPE_WRITE ||
526 zio->io_child_type == ZIO_CHILD_DDT)
527 zio->io_bp = &zio->io_bp_copy; /* so caller can free */
528 if (zio->io_child_type == ZIO_CHILD_LOGICAL)
529 zio->io_logical = zio;
530 if (zio->io_child_type > ZIO_CHILD_GANG && BP_IS_GANG(bp))
531 pipeline |= ZIO_GANG_STAGES;
532 }
533
534 zio->io_spa = spa;
535 zio->io_txg = txg;
536 zio->io_done = done;
537 zio->io_private = private;
538 zio->io_type = type;
539 zio->io_priority = priority;
540 zio->io_vd = vd;
541 zio->io_offset = offset;
542 zio->io_orig_data = zio->io_data = data;
543 zio->io_orig_size = zio->io_size = size;
544 zio->io_orig_flags = zio->io_flags = flags;
545 zio->io_orig_stage = zio->io_stage = stage;
546 zio->io_orig_pipeline = zio->io_pipeline = pipeline;
547
548 zio->io_state[ZIO_WAIT_READY] = (stage >= ZIO_STAGE_READY);
549 zio->io_state[ZIO_WAIT_DONE] = (stage >= ZIO_STAGE_DONE);
550
551 if (zb != NULL)
552 zio->io_bookmark = *zb;
553
554 if (pio != NULL) {
555 if (zio->io_logical == NULL)
556 zio->io_logical = pio->io_logical;
557 if (zio->io_child_type == ZIO_CHILD_GANG)
558 zio->io_gang_leader = pio->io_gang_leader;
559 zio_add_child(pio, zio);
560 }
561
562 return (zio);
563 }
564
565 static void
566 zio_destroy(zio_t *zio)
567 {
568 list_destroy(&zio->io_parent_list);
569 list_destroy(&zio->io_child_list);
570 mutex_destroy(&zio->io_lock);
571 cv_destroy(&zio->io_cv);
572 kmem_cache_free(zio_cache, zio);
573 }
574
575 zio_t *
576 zio_null(zio_t *pio, spa_t *spa, vdev_t *vd, zio_done_func_t *done,
577 void *private, enum zio_flag flags)
578 {
579 zio_t *zio;
580
581 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private,
582 ZIO_TYPE_NULL, ZIO_PRIORITY_NOW, flags, vd, 0, NULL,
583 ZIO_STAGE_OPEN, ZIO_INTERLOCK_PIPELINE);
584
585 return (zio);
586 }
587
588 zio_t *
589 zio_root(spa_t *spa, zio_done_func_t *done, void *private, enum zio_flag flags)
590 {
591 return (zio_null(NULL, spa, NULL, done, private, flags));
592 }
593
594 zio_t *
595 zio_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
596 void *data, uint64_t size, zio_done_func_t *done, void *private,
597 int priority, enum zio_flag flags, const zbookmark_t *zb)
598 {
599 zio_t *zio;
600
601 zio = zio_create(pio, spa, BP_PHYSICAL_BIRTH(bp), bp,
602 data, size, done, private,
603 ZIO_TYPE_READ, priority, flags, NULL, 0, zb,
604 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ?
605 ZIO_DDT_CHILD_READ_PIPELINE : ZIO_READ_PIPELINE);
606
607 return (zio);
608 }
609
610 zio_t *
611 zio_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
612 void *data, uint64_t size, const zio_prop_t *zp,
613 zio_done_func_t *ready, zio_done_func_t *done, void *private,
614 int priority, enum zio_flag flags, const zbookmark_t *zb)
615 {
616 zio_t *zio;
617
618 ASSERT(zp->zp_checksum >= ZIO_CHECKSUM_OFF &&
619 zp->zp_checksum < ZIO_CHECKSUM_FUNCTIONS &&
620 zp->zp_compress >= ZIO_COMPRESS_OFF &&
621 zp->zp_compress < ZIO_COMPRESS_FUNCTIONS &&
622 zp->zp_type < DMU_OT_NUMTYPES &&
623 zp->zp_level < 32 &&
624 zp->zp_copies > 0 &&
625 zp->zp_copies <= spa_max_replication(spa) &&
626 zp->zp_dedup <= 1 &&
627 zp->zp_dedup_verify <= 1);
628
629 zio = zio_create(pio, spa, txg, bp, data, size, done, private,
630 ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb,
631 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ?
632 ZIO_DDT_CHILD_WRITE_PIPELINE : ZIO_WRITE_PIPELINE);
633
634 zio->io_ready = ready;
635 zio->io_prop = *zp;
636
637 return (zio);
638 }
639
640 zio_t *
641 zio_rewrite(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, void *data,
642 uint64_t size, zio_done_func_t *done, void *private, int priority,
643 enum zio_flag flags, zbookmark_t *zb)
644 {
645 zio_t *zio;
646
647 zio = zio_create(pio, spa, txg, bp, data, size, done, private,
648 ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb,
649 ZIO_STAGE_OPEN, ZIO_REWRITE_PIPELINE);
650
651 return (zio);
652 }
653
654 void
655 zio_write_override(zio_t *zio, blkptr_t *bp, int copies)
656 {
657 ASSERT(zio->io_type == ZIO_TYPE_WRITE);
658 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
659 ASSERT(zio->io_stage == ZIO_STAGE_OPEN);
660 ASSERT(zio->io_txg == spa_syncing_txg(zio->io_spa));
661
662 zio->io_prop.zp_copies = copies;
663 zio->io_bp_override = bp;
664 }
665
666 void
667 zio_free(spa_t *spa, uint64_t txg, const blkptr_t *bp)
668 {
669 bplist_append(&spa->spa_free_bplist[txg & TXG_MASK], bp);
670 }
671
672 zio_t *
673 zio_free_sync(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
674 enum zio_flag flags)
675 {
676 zio_t *zio;
677
678 dprintf_bp(bp, "freeing in txg %llu, pass %u",
679 (longlong_t)txg, spa->spa_sync_pass);
680
681 ASSERT(!BP_IS_HOLE(bp));
682 ASSERT(spa_syncing_txg(spa) == txg);
683 ASSERT(spa_sync_pass(spa) <= SYNC_PASS_DEFERRED_FREE);
684
685 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp),
686 NULL, NULL, ZIO_TYPE_FREE, ZIO_PRIORITY_FREE, flags,
687 NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_FREE_PIPELINE);
688
689 return (zio);
690 }
691
692 zio_t *
693 zio_claim(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
694 zio_done_func_t *done, void *private, enum zio_flag flags)
695 {
696 zio_t *zio;
697
698 /*
699 * A claim is an allocation of a specific block. Claims are needed
700 * to support immediate writes in the intent log. The issue is that
701 * immediate writes contain committed data, but in a txg that was
702 * *not* committed. Upon opening the pool after an unclean shutdown,
703 * the intent log claims all blocks that contain immediate write data
704 * so that the SPA knows they're in use.
705 *
706 * All claims *must* be resolved in the first txg -- before the SPA
707 * starts allocating blocks -- so that nothing is allocated twice.
708 * If txg == 0 we just verify that the block is claimable.
709 */
710 ASSERT3U(spa->spa_uberblock.ub_rootbp.blk_birth, <, spa_first_txg(spa));
711 ASSERT(txg == spa_first_txg(spa) || txg == 0);
712 ASSERT(!BP_GET_DEDUP(bp) || !spa_writeable(spa)); /* zdb(1M) */
713
714 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp),
715 done, private, ZIO_TYPE_CLAIM, ZIO_PRIORITY_NOW, flags,
716 NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_CLAIM_PIPELINE);
717
718 return (zio);
719 }
720
721 zio_t *
722 zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd,
723 zio_done_func_t *done, void *private, int priority, enum zio_flag flags)
724 {
725 zio_t *zio;
726 int c;
727
728 if (vd->vdev_children == 0) {
729 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private,
730 ZIO_TYPE_IOCTL, priority, flags, vd, 0, NULL,
731 ZIO_STAGE_OPEN, ZIO_IOCTL_PIPELINE);
732
733 zio->io_cmd = cmd;
734 } else {
735 zio = zio_null(pio, spa, NULL, NULL, NULL, flags);
736
737 for (c = 0; c < vd->vdev_children; c++)
738 zio_nowait(zio_ioctl(zio, spa, vd->vdev_child[c], cmd,
739 done, private, priority, flags));
740 }
741
742 return (zio);
743 }
744
745 zio_t *
746 zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size,
747 void *data, int checksum, zio_done_func_t *done, void *private,
748 int priority, enum zio_flag flags, boolean_t labels)
749 {
750 zio_t *zio;
751
752 ASSERT(vd->vdev_children == 0);
753 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE ||
754 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE);
755 ASSERT3U(offset + size, <=, vd->vdev_psize);
756
757 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private,
758 ZIO_TYPE_READ, priority, flags, vd, offset, NULL,
759 ZIO_STAGE_OPEN, ZIO_READ_PHYS_PIPELINE);
760
761 zio->io_prop.zp_checksum = checksum;
762
763 return (zio);
764 }
765
766 zio_t *
767 zio_write_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size,
768 void *data, int checksum, zio_done_func_t *done, void *private,
769 int priority, enum zio_flag flags, boolean_t labels)
770 {
771 zio_t *zio;
772
773 ASSERT(vd->vdev_children == 0);
774 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE ||
775 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE);
776 ASSERT3U(offset + size, <=, vd->vdev_psize);
777
778 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private,
779 ZIO_TYPE_WRITE, priority, flags, vd, offset, NULL,
780 ZIO_STAGE_OPEN, ZIO_WRITE_PHYS_PIPELINE);
781
782 zio->io_prop.zp_checksum = checksum;
783
784 if (zio_checksum_table[checksum].ci_eck) {
785 /*
786 * zec checksums are necessarily destructive -- they modify
787 * the end of the write buffer to hold the verifier/checksum.
788 * Therefore, we must make a local copy in case the data is
789 * being written to multiple places in parallel.
790 */
791 void *wbuf = zio_buf_alloc(size);
792 bcopy(data, wbuf, size);
793 zio_push_transform(zio, wbuf, size, size, NULL);
794 }
795
796 return (zio);
797 }
798
799 /*
800 * Create a child I/O to do some work for us.
801 */
802 zio_t *
803 zio_vdev_child_io(zio_t *pio, blkptr_t *bp, vdev_t *vd, uint64_t offset,
804 void *data, uint64_t size, int type, int priority, enum zio_flag flags,
805 zio_done_func_t *done, void *private)
806 {
807 enum zio_stage pipeline = ZIO_VDEV_CHILD_PIPELINE;
808 zio_t *zio;
809
810 ASSERT(vd->vdev_parent ==
811 (pio->io_vd ? pio->io_vd : pio->io_spa->spa_root_vdev));
812
813 if (type == ZIO_TYPE_READ && bp != NULL) {
814 /*
815 * If we have the bp, then the child should perform the
816 * checksum and the parent need not. This pushes error
817 * detection as close to the leaves as possible and
818 * eliminates redundant checksums in the interior nodes.
819 */
820 pipeline |= ZIO_STAGE_CHECKSUM_VERIFY;
821 pio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY;
822 }
823
824 if (vd->vdev_children == 0)
825 offset += VDEV_LABEL_START_SIZE;
826
827 flags |= ZIO_VDEV_CHILD_FLAGS(pio) | ZIO_FLAG_DONT_PROPAGATE;
828
829 /*
830 * If we've decided to do a repair, the write is not speculative --
831 * even if the original read was.
832 */
833 if (flags & ZIO_FLAG_IO_REPAIR)
834 flags &= ~ZIO_FLAG_SPECULATIVE;
835
836 zio = zio_create(pio, pio->io_spa, pio->io_txg, bp, data, size,
837 done, private, type, priority, flags, vd, offset, &pio->io_bookmark,
838 ZIO_STAGE_VDEV_IO_START >> 1, pipeline);
839
840 return (zio);
841 }
842
843 zio_t *
844 zio_vdev_delegated_io(vdev_t *vd, uint64_t offset, void *data, uint64_t size,
845 int type, int priority, enum zio_flag flags,
846 zio_done_func_t *done, void *private)
847 {
848 zio_t *zio;
849
850 ASSERT(vd->vdev_ops->vdev_op_leaf);
851
852 zio = zio_create(NULL, vd->vdev_spa, 0, NULL,
853 data, size, done, private, type, priority,
854 flags | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_RETRY,
855 vd, offset, NULL,
856 ZIO_STAGE_VDEV_IO_START >> 1, ZIO_VDEV_CHILD_PIPELINE);
857
858 return (zio);
859 }
860
861 void
862 zio_flush(zio_t *zio, vdev_t *vd)
863 {
864 zio_nowait(zio_ioctl(zio, zio->io_spa, vd, DKIOCFLUSHWRITECACHE,
865 NULL, NULL, ZIO_PRIORITY_NOW,
866 ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY));
867 }
868
869 void
870 zio_shrink(zio_t *zio, uint64_t size)
871 {
872 ASSERT(zio->io_executor == NULL);
873 ASSERT(zio->io_orig_size == zio->io_size);
874 ASSERT(size <= zio->io_size);
875
876 /*
877 * We don't shrink for raidz because of problems with the
878 * reconstruction when reading back less than the block size.
879 * Note, BP_IS_RAIDZ() assumes no compression.
880 */
881 ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF);
882 if (!BP_IS_RAIDZ(zio->io_bp))
883 zio->io_orig_size = zio->io_size = size;
884 }
885
886 /*
887 * ==========================================================================
888 * Prepare to read and write logical blocks
889 * ==========================================================================
890 */
891
892 static int
893 zio_read_bp_init(zio_t *zio)
894 {
895 blkptr_t *bp = zio->io_bp;
896
897 if (BP_GET_COMPRESS(bp) != ZIO_COMPRESS_OFF &&
898 zio->io_child_type == ZIO_CHILD_LOGICAL &&
899 !(zio->io_flags & ZIO_FLAG_RAW)) {
900 uint64_t psize = BP_GET_PSIZE(bp);
901 void *cbuf = zio_buf_alloc(psize);
902
903 zio_push_transform(zio, cbuf, psize, psize, zio_decompress);
904 }
905
906 if (!dmu_ot[BP_GET_TYPE(bp)].ot_metadata && BP_GET_LEVEL(bp) == 0)
907 zio->io_flags |= ZIO_FLAG_DONT_CACHE;
908
909 if (BP_GET_TYPE(bp) == DMU_OT_DDT_ZAP)
910 zio->io_flags |= ZIO_FLAG_DONT_CACHE;
911
912 if (BP_GET_DEDUP(bp) && zio->io_child_type == ZIO_CHILD_LOGICAL)
913 zio->io_pipeline = ZIO_DDT_READ_PIPELINE;
914
915 return (ZIO_PIPELINE_CONTINUE);
916 }
917
918 static int
919 zio_write_bp_init(zio_t *zio)
920 {
921 spa_t *spa = zio->io_spa;
922 zio_prop_t *zp = &zio->io_prop;
923 enum zio_compress compress = zp->zp_compress;
924 blkptr_t *bp = zio->io_bp;
925 uint64_t lsize = zio->io_size;
926 uint64_t psize = lsize;
927 int pass = 1;
928
929 /*
930 * If our children haven't all reached the ready stage,
931 * wait for them and then repeat this pipeline stage.
932 */
933 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) ||
934 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_READY))
935 return (ZIO_PIPELINE_STOP);
936
937 if (!IO_IS_ALLOCATING(zio))
938 return (ZIO_PIPELINE_CONTINUE);
939
940 ASSERT(zio->io_child_type != ZIO_CHILD_DDT);
941
942 if (zio->io_bp_override) {
943 ASSERT(bp->blk_birth != zio->io_txg);
944 ASSERT(BP_GET_DEDUP(zio->io_bp_override) == 0);
945
946 *bp = *zio->io_bp_override;
947 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
948
949 if (BP_IS_HOLE(bp) || !zp->zp_dedup)
950 return (ZIO_PIPELINE_CONTINUE);
951
952 ASSERT(zio_checksum_table[zp->zp_checksum].ci_dedup ||
953 zp->zp_dedup_verify);
954
955 if (BP_GET_CHECKSUM(bp) == zp->zp_checksum) {
956 BP_SET_DEDUP(bp, 1);
957 zio->io_pipeline |= ZIO_STAGE_DDT_WRITE;
958 return (ZIO_PIPELINE_CONTINUE);
959 }
960 zio->io_bp_override = NULL;
961 BP_ZERO(bp);
962 }
963
964 if (bp->blk_birth == zio->io_txg) {
965 /*
966 * We're rewriting an existing block, which means we're
967 * working on behalf of spa_sync(). For spa_sync() to
968 * converge, it must eventually be the case that we don't
969 * have to allocate new blocks. But compression changes
970 * the blocksize, which forces a reallocate, and makes
971 * convergence take longer. Therefore, after the first
972 * few passes, stop compressing to ensure convergence.
973 */
974 pass = spa_sync_pass(spa);
975
976 ASSERT(zio->io_txg == spa_syncing_txg(spa));
977 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
978 ASSERT(!BP_GET_DEDUP(bp));
979
980 if (pass > SYNC_PASS_DONT_COMPRESS)
981 compress = ZIO_COMPRESS_OFF;
982
983 /* Make sure someone doesn't change their mind on overwrites */
984 ASSERT(MIN(zp->zp_copies + BP_IS_GANG(bp),
985 spa_max_replication(spa)) == BP_GET_NDVAS(bp));
986 }
987
988 if (compress != ZIO_COMPRESS_OFF) {
989 void *cbuf = zio_buf_alloc(lsize);
990 psize = zio_compress_data(compress, zio->io_data, cbuf, lsize);
991 if (psize == 0 || psize == lsize) {
992 compress = ZIO_COMPRESS_OFF;
993 zio_buf_free(cbuf, lsize);
994 } else {
995 ASSERT(psize < lsize);
996 zio_push_transform(zio, cbuf, psize, lsize, NULL);
997 }
998 }
999
1000 /*
1001 * The final pass of spa_sync() must be all rewrites, but the first
1002 * few passes offer a trade-off: allocating blocks defers convergence,
1003 * but newly allocated blocks are sequential, so they can be written
1004 * to disk faster. Therefore, we allow the first few passes of
1005 * spa_sync() to allocate new blocks, but force rewrites after that.
1006 * There should only be a handful of blocks after pass 1 in any case.
1007 */
1008 if (bp->blk_birth == zio->io_txg && BP_GET_PSIZE(bp) == psize &&
1009 pass > SYNC_PASS_REWRITE) {
1010 ASSERT(psize != 0);
1011 enum zio_stage gang_stages = zio->io_pipeline & ZIO_GANG_STAGES;
1012 zio->io_pipeline = ZIO_REWRITE_PIPELINE | gang_stages;
1013 zio->io_flags |= ZIO_FLAG_IO_REWRITE;
1014 } else {
1015 BP_ZERO(bp);
1016 zio->io_pipeline = ZIO_WRITE_PIPELINE;
1017 }
1018
1019 if (psize == 0) {
1020 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1021 } else {
1022 ASSERT(zp->zp_checksum != ZIO_CHECKSUM_GANG_HEADER);
1023 BP_SET_LSIZE(bp, lsize);
1024 BP_SET_PSIZE(bp, psize);
1025 BP_SET_COMPRESS(bp, compress);
1026 BP_SET_CHECKSUM(bp, zp->zp_checksum);
1027 BP_SET_TYPE(bp, zp->zp_type);
1028 BP_SET_LEVEL(bp, zp->zp_level);
1029 BP_SET_DEDUP(bp, zp->zp_dedup);
1030 BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER);
1031 if (zp->zp_dedup) {
1032 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1033 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE));
1034 zio->io_pipeline = ZIO_DDT_WRITE_PIPELINE;
1035 }
1036 }
1037
1038 return (ZIO_PIPELINE_CONTINUE);
1039 }
1040
1041 static int
1042 zio_free_bp_init(zio_t *zio)
1043 {
1044 blkptr_t *bp = zio->io_bp;
1045
1046 if (zio->io_child_type == ZIO_CHILD_LOGICAL) {
1047 if (BP_GET_DEDUP(bp))
1048 zio->io_pipeline = ZIO_DDT_FREE_PIPELINE;
1049 }
1050
1051 return (ZIO_PIPELINE_CONTINUE);
1052 }
1053
1054 /*
1055 * ==========================================================================
1056 * Execute the I/O pipeline
1057 * ==========================================================================
1058 */
1059
1060 static void
1061 zio_taskq_dispatch(zio_t *zio, enum zio_taskq_type q, boolean_t cutinline)
1062 {
1063 spa_t *spa = zio->io_spa;
1064 zio_type_t t = zio->io_type;
1065 int flags = (cutinline ? TQ_FRONT : 0);
1066
1067 /*
1068 * If we're a config writer or a probe, the normal issue and
1069 * interrupt threads may all be blocked waiting for the config lock.
1070 * In this case, select the otherwise-unused taskq for ZIO_TYPE_NULL.
1071 */
1072 if (zio->io_flags & (ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_PROBE))
1073 t = ZIO_TYPE_NULL;
1074
1075 /*
1076 * A similar issue exists for the L2ARC write thread until L2ARC 2.0.
1077 */
1078 if (t == ZIO_TYPE_WRITE && zio->io_vd && zio->io_vd->vdev_aux)
1079 t = ZIO_TYPE_NULL;
1080
1081 /*
1082 * If this is a high priority I/O, then use the high priority taskq.
1083 */
1084 if (zio->io_priority == ZIO_PRIORITY_NOW &&
1085 spa->spa_zio_taskq[t][q + 1] != NULL)
1086 q++;
1087
1088 ASSERT3U(q, <, ZIO_TASKQ_TYPES);
1089
1090 /*
1091 * NB: We are assuming that the zio can only be dispatched
1092 * to a single taskq at a time. It would be a grievous error
1093 * to dispatch the zio to another taskq at the same time.
1094 */
1095 ASSERT(zio->io_tqent.tqent_next == NULL);
1096 taskq_dispatch_ent(spa->spa_zio_taskq[t][q],
1097 (task_func_t *)zio_execute, zio, flags, &zio->io_tqent);
1098 }
1099
1100 static boolean_t
1101 zio_taskq_member(zio_t *zio, enum zio_taskq_type q)
1102 {
1103 kthread_t *executor = zio->io_executor;
1104 spa_t *spa = zio->io_spa;
1105
1106 for (zio_type_t t = 0; t < ZIO_TYPES; t++)
1107 if (taskq_member(spa->spa_zio_taskq[t][q], executor))
1108 return (B_TRUE);
1109
1110 return (B_FALSE);
1111 }
1112
1113 static int
1114 zio_issue_async(zio_t *zio)
1115 {
1116 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE);
1117
1118 return (ZIO_PIPELINE_STOP);
1119 }
1120
1121 void
1122 zio_interrupt(zio_t *zio)
1123 {
1124 zio_taskq_dispatch(zio, ZIO_TASKQ_INTERRUPT, B_FALSE);
1125 }
1126
1127 /*
1128 * Execute the I/O pipeline until one of the following occurs:
1129 * (1) the I/O completes; (2) the pipeline stalls waiting for
1130 * dependent child I/Os; (3) the I/O issues, so we're waiting
1131 * for an I/O completion interrupt; (4) the I/O is delegated by
1132 * vdev-level caching or aggregation; (5) the I/O is deferred
1133 * due to vdev-level queueing; (6) the I/O is handed off to
1134 * another thread. In all cases, the pipeline stops whenever
1135 * there's no CPU work; it never burns a thread in cv_wait().
1136 *
1137 * There's no locking on io_stage because there's no legitimate way
1138 * for multiple threads to be attempting to process the same I/O.
1139 */
1140 static zio_pipe_stage_t *zio_pipeline[];
1141
1142 void
1143 zio_execute(zio_t *zio)
1144 {
1145 zio->io_executor = curthread;
1146
1147 while (zio->io_stage < ZIO_STAGE_DONE) {
1148 enum zio_stage pipeline = zio->io_pipeline;
1149 enum zio_stage stage = zio->io_stage;
1150 int rv;
1151
1152 ASSERT(!MUTEX_HELD(&zio->io_lock));
1153 ASSERT(ISP2(stage));
1154 ASSERT(zio->io_stall == NULL);
1155
1156 do {
1157 stage <<= 1;
1158 } while ((stage & pipeline) == 0);
1159
1160 ASSERT(stage <= ZIO_STAGE_DONE);
1161
1162 /*
1163 * If we are in interrupt context and this pipeline stage
1164 * will grab a config lock that is held across I/O,
1165 * or may wait for an I/O that needs an interrupt thread
1166 * to complete, issue async to avoid deadlock.
1167 *
1168 * For VDEV_IO_START, we cut in line so that the io will
1169 * be sent to disk promptly.
1170 */
1171 if ((stage & ZIO_BLOCKING_STAGES) && zio->io_vd == NULL &&
1172 zio_taskq_member(zio, ZIO_TASKQ_INTERRUPT)) {
1173 boolean_t cut = (stage == ZIO_STAGE_VDEV_IO_START) ?
1174 zio_requeue_io_start_cut_in_line : B_FALSE;
1175 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, cut);
1176 return;
1177 }
1178
1179 zio->io_stage = stage;
1180 rv = zio_pipeline[highbit(stage) - 1](zio);
1181
1182 if (rv == ZIO_PIPELINE_STOP)
1183 return;
1184
1185 ASSERT(rv == ZIO_PIPELINE_CONTINUE);
1186 }
1187 }
1188
1189 /*
1190 * ==========================================================================
1191 * Initiate I/O, either sync or async
1192 * ==========================================================================
1193 */
1194 int
1195 zio_wait(zio_t *zio)
1196 {
1197 int error;
1198
1199 ASSERT(zio->io_stage == ZIO_STAGE_OPEN);
1200 ASSERT(zio->io_executor == NULL);
1201
1202 zio->io_waiter = curthread;
1203
1204 zio_execute(zio);
1205
1206 mutex_enter(&zio->io_lock);
1207 while (zio->io_executor != NULL)
1208 cv_wait(&zio->io_cv, &zio->io_lock);
1209 mutex_exit(&zio->io_lock);
1210
1211 error = zio->io_error;
1212 zio_destroy(zio);
1213
1214 return (error);
1215 }
1216
1217 void
1218 zio_nowait(zio_t *zio)
1219 {
1220 ASSERT(zio->io_executor == NULL);
1221
1222 if (zio->io_child_type == ZIO_CHILD_LOGICAL &&
1223 zio_unique_parent(zio) == NULL) {
1224 /*
1225 * This is a logical async I/O with no parent to wait for it.
1226 * We add it to the spa_async_root_zio "Godfather" I/O which
1227 * will ensure they complete prior to unloading the pool.
1228 */
1229 spa_t *spa = zio->io_spa;
1230
1231 zio_add_child(spa->spa_async_zio_root, zio);
1232 }
1233
1234 zio_execute(zio);
1235 }
1236
1237 /*
1238 * ==========================================================================
1239 * Reexecute or suspend/resume failed I/O
1240 * ==========================================================================
1241 */
1242
1243 static void
1244 zio_reexecute(zio_t *pio)
1245 {
1246 zio_t *cio, *cio_next;
1247
1248 ASSERT(pio->io_child_type == ZIO_CHILD_LOGICAL);
1249 ASSERT(pio->io_orig_stage == ZIO_STAGE_OPEN);
1250 ASSERT(pio->io_gang_leader == NULL);
1251 ASSERT(pio->io_gang_tree == NULL);
1252
1253 pio->io_flags = pio->io_orig_flags;
1254 pio->io_stage = pio->io_orig_stage;
1255 pio->io_pipeline = pio->io_orig_pipeline;
1256 pio->io_reexecute = 0;
1257 pio->io_error = 0;
1258 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
1259 pio->io_state[w] = 0;
1260 for (int c = 0; c < ZIO_CHILD_TYPES; c++)
1261 pio->io_child_error[c] = 0;
1262
1263 if (IO_IS_ALLOCATING(pio))
1264 BP_ZERO(pio->io_bp);
1265
1266 /*
1267 * As we reexecute pio's children, new children could be created.
1268 * New children go to the head of pio's io_child_list, however,
1269 * so we will (correctly) not reexecute them. The key is that
1270 * the remainder of pio's io_child_list, from 'cio_next' onward,
1271 * cannot be affected by any side effects of reexecuting 'cio'.
1272 */
1273 for (cio = zio_walk_children(pio); cio != NULL; cio = cio_next) {
1274 cio_next = zio_walk_children(pio);
1275 mutex_enter(&pio->io_lock);
1276 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
1277 pio->io_children[cio->io_child_type][w]++;
1278 mutex_exit(&pio->io_lock);
1279 zio_reexecute(cio);
1280 }
1281
1282 /*
1283 * Now that all children have been reexecuted, execute the parent.
1284 * We don't reexecute "The Godfather" I/O here as it's the
1285 * responsibility of the caller to wait on him.
1286 */
1287 if (!(pio->io_flags & ZIO_FLAG_GODFATHER))
1288 zio_execute(pio);
1289 }
1290
1291 void
1292 zio_suspend(spa_t *spa, zio_t *zio)
1293 {
1294 if (spa_get_failmode(spa) == ZIO_FAILURE_MODE_PANIC)
1295 fm_panic("Pool '%s' has encountered an uncorrectable I/O "
1296 "failure and the failure mode property for this pool "
1297 "is set to panic.", spa_name(spa));
1298
1299 zfs_ereport_post(FM_EREPORT_ZFS_IO_FAILURE, spa, NULL, NULL, 0, 0);
1300
1301 mutex_enter(&spa->spa_suspend_lock);
1302
1303 if (spa->spa_suspend_zio_root == NULL)
1304 spa->spa_suspend_zio_root = zio_root(spa, NULL, NULL,
1305 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE |
1306 ZIO_FLAG_GODFATHER);
1307
1308 spa->spa_suspended = B_TRUE;
1309
1310 if (zio != NULL) {
1311 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER));
1312 ASSERT(zio != spa->spa_suspend_zio_root);
1313 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1314 ASSERT(zio_unique_parent(zio) == NULL);
1315 ASSERT(zio->io_stage == ZIO_STAGE_DONE);
1316 zio_add_child(spa->spa_suspend_zio_root, zio);
1317 }
1318
1319 mutex_exit(&spa->spa_suspend_lock);
1320 }
1321
1322 int
1323 zio_resume(spa_t *spa)
1324 {
1325 zio_t *pio;
1326
1327 /*
1328 * Reexecute all previously suspended i/o.
1329 */
1330 mutex_enter(&spa->spa_suspend_lock);
1331 spa->spa_suspended = B_FALSE;
1332 cv_broadcast(&spa->spa_suspend_cv);
1333 pio = spa->spa_suspend_zio_root;
1334 spa->spa_suspend_zio_root = NULL;
1335 mutex_exit(&spa->spa_suspend_lock);
1336
1337 if (pio == NULL)
1338 return (0);
1339
1340 zio_reexecute(pio);
1341 return (zio_wait(pio));
1342 }
1343
1344 void
1345 zio_resume_wait(spa_t *spa)
1346 {
1347 mutex_enter(&spa->spa_suspend_lock);
1348 while (spa_suspended(spa))
1349 cv_wait(&spa->spa_suspend_cv, &spa->spa_suspend_lock);
1350 mutex_exit(&spa->spa_suspend_lock);
1351 }
1352
1353 /*
1354 * ==========================================================================
1355 * Gang blocks.
1356 *
1357 * A gang block is a collection of small blocks that looks to the DMU
1358 * like one large block. When zio_dva_allocate() cannot find a block
1359 * of the requested size, due to either severe fragmentation or the pool
1360 * being nearly full, it calls zio_write_gang_block() to construct the
1361 * block from smaller fragments.
1362 *
1363 * A gang block consists of a gang header (zio_gbh_phys_t) and up to
1364 * three (SPA_GBH_NBLKPTRS) gang members. The gang header is just like
1365 * an indirect block: it's an array of block pointers. It consumes
1366 * only one sector and hence is allocatable regardless of fragmentation.
1367 * The gang header's bps point to its gang members, which hold the data.
1368 *
1369 * Gang blocks are self-checksumming, using the bp's <vdev, offset, txg>
1370 * as the verifier to ensure uniqueness of the SHA256 checksum.
1371 * Critically, the gang block bp's blk_cksum is the checksum of the data,
1372 * not the gang header. This ensures that data block signatures (needed for
1373 * deduplication) are independent of how the block is physically stored.
1374 *
1375 * Gang blocks can be nested: a gang member may itself be a gang block.
1376 * Thus every gang block is a tree in which root and all interior nodes are
1377 * gang headers, and the leaves are normal blocks that contain user data.
1378 * The root of the gang tree is called the gang leader.
1379 *
1380 * To perform any operation (read, rewrite, free, claim) on a gang block,
1381 * zio_gang_assemble() first assembles the gang tree (minus data leaves)
1382 * in the io_gang_tree field of the original logical i/o by recursively
1383 * reading the gang leader and all gang headers below it. This yields
1384 * an in-core tree containing the contents of every gang header and the
1385 * bps for every constituent of the gang block.
1386 *
1387 * With the gang tree now assembled, zio_gang_issue() just walks the gang tree
1388 * and invokes a callback on each bp. To free a gang block, zio_gang_issue()
1389 * calls zio_free_gang() -- a trivial wrapper around zio_free() -- for each bp.
1390 * zio_claim_gang() provides a similarly trivial wrapper for zio_claim().
1391 * zio_read_gang() is a wrapper around zio_read() that omits reading gang
1392 * headers, since we already have those in io_gang_tree. zio_rewrite_gang()
1393 * performs a zio_rewrite() of the data or, for gang headers, a zio_rewrite()
1394 * of the gang header plus zio_checksum_compute() of the data to update the
1395 * gang header's blk_cksum as described above.
1396 *
1397 * The two-phase assemble/issue model solves the problem of partial failure --
1398 * what if you'd freed part of a gang block but then couldn't read the
1399 * gang header for another part? Assembling the entire gang tree first
1400 * ensures that all the necessary gang header I/O has succeeded before
1401 * starting the actual work of free, claim, or write. Once the gang tree
1402 * is assembled, free and claim are in-memory operations that cannot fail.
1403 *
1404 * In the event that a gang write fails, zio_dva_unallocate() walks the
1405 * gang tree to immediately free (i.e. insert back into the space map)
1406 * everything we've allocated. This ensures that we don't get ENOSPC
1407 * errors during repeated suspend/resume cycles due to a flaky device.
1408 *
1409 * Gang rewrites only happen during sync-to-convergence. If we can't assemble
1410 * the gang tree, we won't modify the block, so we can safely defer the free
1411 * (knowing that the block is still intact). If we *can* assemble the gang
1412 * tree, then even if some of the rewrites fail, zio_dva_unallocate() will free
1413 * each constituent bp and we can allocate a new block on the next sync pass.
1414 *
1415 * In all cases, the gang tree allows complete recovery from partial failure.
1416 * ==========================================================================
1417 */
1418
1419 static zio_t *
1420 zio_read_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1421 {
1422 if (gn != NULL)
1423 return (pio);
1424
1425 return (zio_read(pio, pio->io_spa, bp, data, BP_GET_PSIZE(bp),
1426 NULL, NULL, pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio),
1427 &pio->io_bookmark));
1428 }
1429
1430 zio_t *
1431 zio_rewrite_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1432 {
1433 zio_t *zio;
1434
1435 if (gn != NULL) {
1436 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp,
1437 gn->gn_gbh, SPA_GANGBLOCKSIZE, NULL, NULL, pio->io_priority,
1438 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
1439 /*
1440 * As we rewrite each gang header, the pipeline will compute
1441 * a new gang block header checksum for it; but no one will
1442 * compute a new data checksum, so we do that here. The one
1443 * exception is the gang leader: the pipeline already computed
1444 * its data checksum because that stage precedes gang assembly.
1445 * (Presently, nothing actually uses interior data checksums;
1446 * this is just good hygiene.)
1447 */
1448 if (gn != pio->io_gang_leader->io_gang_tree) {
1449 zio_checksum_compute(zio, BP_GET_CHECKSUM(bp),
1450 data, BP_GET_PSIZE(bp));
1451 }
1452 /*
1453 * If we are here to damage data for testing purposes,
1454 * leave the GBH alone so that we can detect the damage.
1455 */
1456 if (pio->io_gang_leader->io_flags & ZIO_FLAG_INDUCE_DAMAGE)
1457 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES;
1458 } else {
1459 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp,
1460 data, BP_GET_PSIZE(bp), NULL, NULL, pio->io_priority,
1461 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
1462 }
1463
1464 return (zio);
1465 }
1466
1467 /* ARGSUSED */
1468 zio_t *
1469 zio_free_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1470 {
1471 return (zio_free_sync(pio, pio->io_spa, pio->io_txg, bp,
1472 ZIO_GANG_CHILD_FLAGS(pio)));
1473 }
1474
1475 /* ARGSUSED */
1476 zio_t *
1477 zio_claim_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1478 {
1479 return (zio_claim(pio, pio->io_spa, pio->io_txg, bp,
1480 NULL, NULL, ZIO_GANG_CHILD_FLAGS(pio)));
1481 }
1482
1483 static zio_gang_issue_func_t *zio_gang_issue_func[ZIO_TYPES] = {
1484 NULL,
1485 zio_read_gang,
1486 zio_rewrite_gang,
1487 zio_free_gang,
1488 zio_claim_gang,
1489 NULL
1490 };
1491
1492 static void zio_gang_tree_assemble_done(zio_t *zio);
1493
1494 static zio_gang_node_t *
1495 zio_gang_node_alloc(zio_gang_node_t **gnpp)
1496 {
1497 zio_gang_node_t *gn;
1498
1499 ASSERT(*gnpp == NULL);
1500
1501 gn = kmem_zalloc(sizeof (*gn), KM_SLEEP);
1502 gn->gn_gbh = zio_buf_alloc(SPA_GANGBLOCKSIZE);
1503 *gnpp = gn;
1504
1505 return (gn);
1506 }
1507
1508 static void
1509 zio_gang_node_free(zio_gang_node_t **gnpp)
1510 {
1511 zio_gang_node_t *gn = *gnpp;
1512
1513 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++)
1514 ASSERT(gn->gn_child[g] == NULL);
1515
1516 zio_buf_free(gn->gn_gbh, SPA_GANGBLOCKSIZE);
1517 kmem_free(gn, sizeof (*gn));
1518 *gnpp = NULL;
1519 }
1520
1521 static void
1522 zio_gang_tree_free(zio_gang_node_t **gnpp)
1523 {
1524 zio_gang_node_t *gn = *gnpp;
1525
1526 if (gn == NULL)
1527 return;
1528
1529 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++)
1530 zio_gang_tree_free(&gn->gn_child[g]);
1531
1532 zio_gang_node_free(gnpp);
1533 }
1534
1535 static void
1536 zio_gang_tree_assemble(zio_t *gio, blkptr_t *bp, zio_gang_node_t **gnpp)
1537 {
1538 zio_gang_node_t *gn = zio_gang_node_alloc(gnpp);
1539
1540 ASSERT(gio->io_gang_leader == gio);
1541 ASSERT(BP_IS_GANG(bp));
1542
1543 zio_nowait(zio_read(gio, gio->io_spa, bp, gn->gn_gbh,
1544 SPA_GANGBLOCKSIZE, zio_gang_tree_assemble_done, gn,
1545 gio->io_priority, ZIO_GANG_CHILD_FLAGS(gio), &gio->io_bookmark));
1546 }
1547
1548 static void
1549 zio_gang_tree_assemble_done(zio_t *zio)
1550 {
1551 zio_t *gio = zio->io_gang_leader;
1552 zio_gang_node_t *gn = zio->io_private;
1553 blkptr_t *bp = zio->io_bp;
1554
1555 ASSERT(gio == zio_unique_parent(zio));
1556 ASSERT(zio->io_child_count == 0);
1557
1558 if (zio->io_error)
1559 return;
1560
1561 if (BP_SHOULD_BYTESWAP(bp))
1562 byteswap_uint64_array(zio->io_data, zio->io_size);
1563
1564 ASSERT(zio->io_data == gn->gn_gbh);
1565 ASSERT(zio->io_size == SPA_GANGBLOCKSIZE);
1566 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC);
1567
1568 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
1569 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g];
1570 if (!BP_IS_GANG(gbp))
1571 continue;
1572 zio_gang_tree_assemble(gio, gbp, &gn->gn_child[g]);
1573 }
1574 }
1575
1576 static void
1577 zio_gang_tree_issue(zio_t *pio, zio_gang_node_t *gn, blkptr_t *bp, void *data)
1578 {
1579 zio_t *gio = pio->io_gang_leader;
1580 zio_t *zio;
1581
1582 ASSERT(BP_IS_GANG(bp) == !!gn);
1583 ASSERT(BP_GET_CHECKSUM(bp) == BP_GET_CHECKSUM(gio->io_bp));
1584 ASSERT(BP_GET_LSIZE(bp) == BP_GET_PSIZE(bp) || gn == gio->io_gang_tree);
1585
1586 /*
1587 * If you're a gang header, your data is in gn->gn_gbh.
1588 * If you're a gang member, your data is in 'data' and gn == NULL.
1589 */
1590 zio = zio_gang_issue_func[gio->io_type](pio, bp, gn, data);
1591
1592 if (gn != NULL) {
1593 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC);
1594
1595 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
1596 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g];
1597 if (BP_IS_HOLE(gbp))
1598 continue;
1599 zio_gang_tree_issue(zio, gn->gn_child[g], gbp, data);
1600 data = (char *)data + BP_GET_PSIZE(gbp);
1601 }
1602 }
1603
1604 if (gn == gio->io_gang_tree)
1605 ASSERT3P((char *)gio->io_data + gio->io_size, ==, data);
1606
1607 if (zio != pio)
1608 zio_nowait(zio);
1609 }
1610
1611 static int
1612 zio_gang_assemble(zio_t *zio)
1613 {
1614 blkptr_t *bp = zio->io_bp;
1615
1616 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == NULL);
1617 ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
1618
1619 zio->io_gang_leader = zio;
1620
1621 zio_gang_tree_assemble(zio, bp, &zio->io_gang_tree);
1622
1623 return (ZIO_PIPELINE_CONTINUE);
1624 }
1625
1626 static int
1627 zio_gang_issue(zio_t *zio)
1628 {
1629 blkptr_t *bp = zio->io_bp;
1630
1631 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE))
1632 return (ZIO_PIPELINE_STOP);
1633
1634 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == zio);
1635 ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
1636
1637 if (zio->io_child_error[ZIO_CHILD_GANG] == 0)
1638 zio_gang_tree_issue(zio, zio->io_gang_tree, bp, zio->io_data);
1639 else
1640 zio_gang_tree_free(&zio->io_gang_tree);
1641
1642 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1643
1644 return (ZIO_PIPELINE_CONTINUE);
1645 }
1646
1647 static void
1648 zio_write_gang_member_ready(zio_t *zio)
1649 {
1650 zio_t *pio = zio_unique_parent(zio);
1651 zio_t *gio = zio->io_gang_leader;
1652 dva_t *cdva = zio->io_bp->blk_dva;
1653 dva_t *pdva = pio->io_bp->blk_dva;
1654 uint64_t asize;
1655
1656 if (BP_IS_HOLE(zio->io_bp))
1657 return;
1658
1659 ASSERT(BP_IS_HOLE(&zio->io_bp_orig));
1660
1661 ASSERT(zio->io_child_type == ZIO_CHILD_GANG);
1662 ASSERT3U(zio->io_prop.zp_copies, ==, gio->io_prop.zp_copies);
1663 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(zio->io_bp));
1664 ASSERT3U(pio->io_prop.zp_copies, <=, BP_GET_NDVAS(pio->io_bp));
1665 ASSERT3U(BP_GET_NDVAS(zio->io_bp), <=, BP_GET_NDVAS(pio->io_bp));
1666
1667 mutex_enter(&pio->io_lock);
1668 for (int d = 0; d < BP_GET_NDVAS(zio->io_bp); d++) {
1669 ASSERT(DVA_GET_GANG(&pdva[d]));
1670 asize = DVA_GET_ASIZE(&pdva[d]);
1671 asize += DVA_GET_ASIZE(&cdva[d]);
1672 DVA_SET_ASIZE(&pdva[d], asize);
1673 }
1674 mutex_exit(&pio->io_lock);
1675 }
1676
1677 static int
1678 zio_write_gang_block(zio_t *pio)
1679 {
1680 spa_t *spa = pio->io_spa;
1681 blkptr_t *bp = pio->io_bp;
1682 zio_t *gio = pio->io_gang_leader;
1683 zio_t *zio;
1684 zio_gang_node_t *gn, **gnpp;
1685 zio_gbh_phys_t *gbh;
1686 uint64_t txg = pio->io_txg;
1687 uint64_t resid = pio->io_size;
1688 uint64_t lsize;
1689 int copies = gio->io_prop.zp_copies;
1690 int gbh_copies = MIN(copies + 1, spa_max_replication(spa));
1691 zio_prop_t zp;
1692 int error;
1693
1694 error = metaslab_alloc(spa, spa_normal_class(spa), SPA_GANGBLOCKSIZE,
1695 bp, gbh_copies, txg, pio == gio ? NULL : gio->io_bp,
1696 METASLAB_HINTBP_FAVOR | METASLAB_GANG_HEADER);
1697 if (error) {
1698 pio->io_error = error;
1699 return (ZIO_PIPELINE_CONTINUE);
1700 }
1701
1702 if (pio == gio) {
1703 gnpp = &gio->io_gang_tree;
1704 } else {
1705 gnpp = pio->io_private;
1706 ASSERT(pio->io_ready == zio_write_gang_member_ready);
1707 }
1708
1709 gn = zio_gang_node_alloc(gnpp);
1710 gbh = gn->gn_gbh;
1711 bzero(gbh, SPA_GANGBLOCKSIZE);
1712
1713 /*
1714 * Create the gang header.
1715 */
1716 zio = zio_rewrite(pio, spa, txg, bp, gbh, SPA_GANGBLOCKSIZE, NULL, NULL,
1717 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
1718
1719 /*
1720 * Create and nowait the gang children.
1721 */
1722 for (int g = 0; resid != 0; resid -= lsize, g++) {
1723 lsize = P2ROUNDUP(resid / (SPA_GBH_NBLKPTRS - g),
1724 SPA_MINBLOCKSIZE);
1725 ASSERT(lsize >= SPA_MINBLOCKSIZE && lsize <= resid);
1726
1727 zp.zp_checksum = gio->io_prop.zp_checksum;
1728 zp.zp_compress = ZIO_COMPRESS_OFF;
1729 zp.zp_type = DMU_OT_NONE;
1730 zp.zp_level = 0;
1731 zp.zp_copies = gio->io_prop.zp_copies;
1732 zp.zp_dedup = 0;
1733 zp.zp_dedup_verify = 0;
1734
1735 zio_nowait(zio_write(zio, spa, txg, &gbh->zg_blkptr[g],
1736 (char *)pio->io_data + (pio->io_size - resid), lsize, &zp,
1737 zio_write_gang_member_ready, NULL, &gn->gn_child[g],
1738 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio),
1739 &pio->io_bookmark));
1740 }
1741
1742 /*
1743 * Set pio's pipeline to just wait for zio to finish.
1744 */
1745 pio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1746
1747 zio_nowait(zio);
1748
1749 return (ZIO_PIPELINE_CONTINUE);
1750 }
1751
1752 /*
1753 * ==========================================================================
1754 * Dedup
1755 * ==========================================================================
1756 */
1757 static void
1758 zio_ddt_child_read_done(zio_t *zio)
1759 {
1760 blkptr_t *bp = zio->io_bp;
1761 ddt_entry_t *dde = zio->io_private;
1762 ddt_phys_t *ddp;
1763 zio_t *pio = zio_unique_parent(zio);
1764
1765 mutex_enter(&pio->io_lock);
1766 ddp = ddt_phys_select(dde, bp);
1767 if (zio->io_error == 0)
1768 ddt_phys_clear(ddp); /* this ddp doesn't need repair */
1769 if (zio->io_error == 0 && dde->dde_repair_data == NULL)
1770 dde->dde_repair_data = zio->io_data;
1771 else
1772 zio_buf_free(zio->io_data, zio->io_size);
1773 mutex_exit(&pio->io_lock);
1774 }
1775
1776 static int
1777 zio_ddt_read_start(zio_t *zio)
1778 {
1779 blkptr_t *bp = zio->io_bp;
1780
1781 ASSERT(BP_GET_DEDUP(bp));
1782 ASSERT(BP_GET_PSIZE(bp) == zio->io_size);
1783 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1784
1785 if (zio->io_child_error[ZIO_CHILD_DDT]) {
1786 ddt_t *ddt = ddt_select(zio->io_spa, bp);
1787 ddt_entry_t *dde = ddt_repair_start(ddt, bp);
1788 ddt_phys_t *ddp = dde->dde_phys;
1789 ddt_phys_t *ddp_self = ddt_phys_select(dde, bp);
1790 blkptr_t blk;
1791
1792 ASSERT(zio->io_vsd == NULL);
1793 zio->io_vsd = dde;
1794
1795 if (ddp_self == NULL)
1796 return (ZIO_PIPELINE_CONTINUE);
1797
1798 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
1799 if (ddp->ddp_phys_birth == 0 || ddp == ddp_self)
1800 continue;
1801 ddt_bp_create(ddt->ddt_checksum, &dde->dde_key, ddp,
1802 &blk);
1803 zio_nowait(zio_read(zio, zio->io_spa, &blk,
1804 zio_buf_alloc(zio->io_size), zio->io_size,
1805 zio_ddt_child_read_done, dde, zio->io_priority,
1806 ZIO_DDT_CHILD_FLAGS(zio) | ZIO_FLAG_DONT_PROPAGATE,
1807 &zio->io_bookmark));
1808 }
1809 return (ZIO_PIPELINE_CONTINUE);
1810 }
1811
1812 zio_nowait(zio_read(zio, zio->io_spa, bp,
1813 zio->io_data, zio->io_size, NULL, NULL, zio->io_priority,
1814 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark));
1815
1816 return (ZIO_PIPELINE_CONTINUE);
1817 }
1818
1819 static int
1820 zio_ddt_read_done(zio_t *zio)
1821 {
1822 blkptr_t *bp = zio->io_bp;
1823
1824 if (zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE))
1825 return (ZIO_PIPELINE_STOP);
1826
1827 ASSERT(BP_GET_DEDUP(bp));
1828 ASSERT(BP_GET_PSIZE(bp) == zio->io_size);
1829 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1830
1831 if (zio->io_child_error[ZIO_CHILD_DDT]) {
1832 ddt_t *ddt = ddt_select(zio->io_spa, bp);
1833 ddt_entry_t *dde = zio->io_vsd;
1834 if (ddt == NULL) {
1835 ASSERT(spa_load_state(zio->io_spa) != SPA_LOAD_NONE);
1836 return (ZIO_PIPELINE_CONTINUE);
1837 }
1838 if (dde == NULL) {
1839 zio->io_stage = ZIO_STAGE_DDT_READ_START >> 1;
1840 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE);
1841 return (ZIO_PIPELINE_STOP);
1842 }
1843 if (dde->dde_repair_data != NULL) {
1844 bcopy(dde->dde_repair_data, zio->io_data, zio->io_size);
1845 zio->io_child_error[ZIO_CHILD_DDT] = 0;
1846 }
1847 ddt_repair_done(ddt, dde);
1848 zio->io_vsd = NULL;
1849 }
1850
1851 ASSERT(zio->io_vsd == NULL);
1852
1853 return (ZIO_PIPELINE_CONTINUE);
1854 }
1855
1856 static boolean_t
1857 zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde)
1858 {
1859 spa_t *spa = zio->io_spa;
1860
1861 /*
1862 * Note: we compare the original data, not the transformed data,
1863 * because when zio->io_bp is an override bp, we will not have
1864 * pushed the I/O transforms. That's an important optimization
1865 * because otherwise we'd compress/encrypt all dmu_sync() data twice.
1866 */
1867 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
1868 zio_t *lio = dde->dde_lead_zio[p];
1869
1870 if (lio != NULL) {
1871 return (lio->io_orig_size != zio->io_orig_size ||
1872 bcmp(zio->io_orig_data, lio->io_orig_data,
1873 zio->io_orig_size) != 0);
1874 }
1875 }
1876
1877 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
1878 ddt_phys_t *ddp = &dde->dde_phys[p];
1879
1880 if (ddp->ddp_phys_birth != 0) {
1881 arc_buf_t *abuf = NULL;
1882 uint32_t aflags = ARC_WAIT;
1883 blkptr_t blk = *zio->io_bp;
1884 int error;
1885
1886 ddt_bp_fill(ddp, &blk, ddp->ddp_phys_birth);
1887
1888 ddt_exit(ddt);
1889
1890 error = arc_read_nolock(NULL, spa, &blk,
1891 arc_getbuf_func, &abuf, ZIO_PRIORITY_SYNC_READ,
1892 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
1893 &aflags, &zio->io_bookmark);
1894
1895 if (error == 0) {
1896 if (arc_buf_size(abuf) != zio->io_orig_size ||
1897 bcmp(abuf->b_data, zio->io_orig_data,
1898 zio->io_orig_size) != 0)
1899 error = EEXIST;
1900 VERIFY(arc_buf_remove_ref(abuf, &abuf) == 1);
1901 }
1902
1903 ddt_enter(ddt);
1904 return (error != 0);
1905 }
1906 }
1907
1908 return (B_FALSE);
1909 }
1910
1911 static void
1912 zio_ddt_child_write_ready(zio_t *zio)
1913 {
1914 int p = zio->io_prop.zp_copies;
1915 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp);
1916 ddt_entry_t *dde = zio->io_private;
1917 ddt_phys_t *ddp = &dde->dde_phys[p];
1918 zio_t *pio;
1919
1920 if (zio->io_error)
1921 return;
1922
1923 ddt_enter(ddt);
1924
1925 ASSERT(dde->dde_lead_zio[p] == zio);
1926
1927 ddt_phys_fill(ddp, zio->io_bp);
1928
1929 while ((pio = zio_walk_parents(zio)) != NULL)
1930 ddt_bp_fill(ddp, pio->io_bp, zio->io_txg);
1931
1932 ddt_exit(ddt);
1933 }
1934
1935 static void
1936 zio_ddt_child_write_done(zio_t *zio)
1937 {
1938 int p = zio->io_prop.zp_copies;
1939 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp);
1940 ddt_entry_t *dde = zio->io_private;
1941 ddt_phys_t *ddp = &dde->dde_phys[p];
1942
1943 ddt_enter(ddt);
1944
1945 ASSERT(ddp->ddp_refcnt == 0);
1946 ASSERT(dde->dde_lead_zio[p] == zio);
1947 dde->dde_lead_zio[p] = NULL;
1948
1949 if (zio->io_error == 0) {
1950 while (zio_walk_parents(zio) != NULL)
1951 ddt_phys_addref(ddp);
1952 } else {
1953 ddt_phys_clear(ddp);
1954 }
1955
1956 ddt_exit(ddt);
1957 }
1958
1959 static void
1960 zio_ddt_ditto_write_done(zio_t *zio)
1961 {
1962 int p = DDT_PHYS_DITTO;
1963 zio_prop_t *zp = &zio->io_prop;
1964 blkptr_t *bp = zio->io_bp;
1965 ddt_t *ddt = ddt_select(zio->io_spa, bp);
1966 ddt_entry_t *dde = zio->io_private;
1967 ddt_phys_t *ddp = &dde->dde_phys[p];
1968 ddt_key_t *ddk = &dde->dde_key;
1969
1970 ddt_enter(ddt);
1971
1972 ASSERT(ddp->ddp_refcnt == 0);
1973 ASSERT(dde->dde_lead_zio[p] == zio);
1974 dde->dde_lead_zio[p] = NULL;
1975
1976 if (zio->io_error == 0) {
1977 ASSERT(ZIO_CHECKSUM_EQUAL(bp->blk_cksum, ddk->ddk_cksum));
1978 ASSERT(zp->zp_copies < SPA_DVAS_PER_BP);
1979 ASSERT(zp->zp_copies == BP_GET_NDVAS(bp) - BP_IS_GANG(bp));
1980 if (ddp->ddp_phys_birth != 0)
1981 ddt_phys_free(ddt, ddk, ddp, zio->io_txg);
1982 ddt_phys_fill(ddp, bp);
1983 }
1984
1985 ddt_exit(ddt);
1986 }
1987
1988 static int
1989 zio_ddt_write(zio_t *zio)
1990 {
1991 spa_t *spa = zio->io_spa;
1992 blkptr_t *bp = zio->io_bp;
1993 uint64_t txg = zio->io_txg;
1994 zio_prop_t *zp = &zio->io_prop;
1995 int p = zp->zp_copies;
1996 int ditto_copies;
1997 zio_t *cio = NULL;
1998 zio_t *dio = NULL;
1999 ddt_t *ddt = ddt_select(spa, bp);
2000 ddt_entry_t *dde;
2001 ddt_phys_t *ddp;
2002
2003 ASSERT(BP_GET_DEDUP(bp));
2004 ASSERT(BP_GET_CHECKSUM(bp) == zp->zp_checksum);
2005 ASSERT(BP_IS_HOLE(bp) || zio->io_bp_override);
2006
2007 ddt_enter(ddt);
2008 dde = ddt_lookup(ddt, bp, B_TRUE);
2009 ddp = &dde->dde_phys[p];
2010
2011 if (zp->zp_dedup_verify && zio_ddt_collision(zio, ddt, dde)) {
2012 /*
2013 * If we're using a weak checksum, upgrade to a strong checksum
2014 * and try again. If we're already using a strong checksum,
2015 * we can't resolve it, so just convert to an ordinary write.
2016 * (And automatically e-mail a paper to Nature?)
2017 */
2018 if (!zio_checksum_table[zp->zp_checksum].ci_dedup) {
2019 zp->zp_checksum = spa_dedup_checksum(spa);
2020 zio_pop_transforms(zio);
2021 zio->io_stage = ZIO_STAGE_OPEN;
2022 BP_ZERO(bp);
2023 } else {
2024 zp->zp_dedup = 0;
2025 }
2026 zio->io_pipeline = ZIO_WRITE_PIPELINE;
2027 ddt_exit(ddt);
2028 return (ZIO_PIPELINE_CONTINUE);
2029 }
2030
2031 ditto_copies = ddt_ditto_copies_needed(ddt, dde, ddp);
2032 ASSERT(ditto_copies < SPA_DVAS_PER_BP);
2033
2034 if (ditto_copies > ddt_ditto_copies_present(dde) &&
2035 dde->dde_lead_zio[DDT_PHYS_DITTO] == NULL) {
2036 zio_prop_t czp = *zp;
2037
2038 czp.zp_copies = ditto_copies;
2039
2040 /*
2041 * If we arrived here with an override bp, we won't have run
2042 * the transform stack, so we won't have the data we need to
2043 * generate a child i/o. So, toss the override bp and restart.
2044 * This is safe, because using the override bp is just an
2045 * optimization; and it's rare, so the cost doesn't matter.
2046 */
2047 if (zio->io_bp_override) {
2048 zio_pop_transforms(zio);
2049 zio->io_stage = ZIO_STAGE_OPEN;
2050 zio->io_pipeline = ZIO_WRITE_PIPELINE;
2051 zio->io_bp_override = NULL;
2052 BP_ZERO(bp);
2053 ddt_exit(ddt);
2054 return (ZIO_PIPELINE_CONTINUE);
2055 }
2056
2057 dio = zio_write(zio, spa, txg, bp, zio->io_orig_data,
2058 zio->io_orig_size, &czp, NULL,
2059 zio_ddt_ditto_write_done, dde, zio->io_priority,
2060 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark);
2061
2062 zio_push_transform(dio, zio->io_data, zio->io_size, 0, NULL);
2063 dde->dde_lead_zio[DDT_PHYS_DITTO] = dio;
2064 }
2065
2066 if (ddp->ddp_phys_birth != 0 || dde->dde_lead_zio[p] != NULL) {
2067 if (ddp->ddp_phys_birth != 0)
2068 ddt_bp_fill(ddp, bp, txg);
2069 if (dde->dde_lead_zio[p] != NULL)
2070 zio_add_child(zio, dde->dde_lead_zio[p]);
2071 else
2072 ddt_phys_addref(ddp);
2073 } else if (zio->io_bp_override) {
2074 ASSERT(bp->blk_birth == txg);
2075 ASSERT(BP_EQUAL(bp, zio->io_bp_override));
2076 ddt_phys_fill(ddp, bp);
2077 ddt_phys_addref(ddp);
2078 } else {
2079 cio = zio_write(zio, spa, txg, bp, zio->io_orig_data,
2080 zio->io_orig_size, zp, zio_ddt_child_write_ready,
2081 zio_ddt_child_write_done, dde, zio->io_priority,
2082 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark);
2083
2084 zio_push_transform(cio, zio->io_data, zio->io_size, 0, NULL);
2085 dde->dde_lead_zio[p] = cio;
2086 }
2087
2088 ddt_exit(ddt);
2089
2090 if (cio)
2091 zio_nowait(cio);
2092 if (dio)
2093 zio_nowait(dio);
2094
2095 return (ZIO_PIPELINE_CONTINUE);
2096 }
2097
2098 ddt_entry_t *freedde; /* for debugging */
2099
2100 static int
2101 zio_ddt_free(zio_t *zio)
2102 {
2103 spa_t *spa = zio->io_spa;
2104 blkptr_t *bp = zio->io_bp;
2105 ddt_t *ddt = ddt_select(spa, bp);
2106 ddt_entry_t *dde;
2107 ddt_phys_t *ddp;
2108
2109 ASSERT(BP_GET_DEDUP(bp));
2110 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
2111
2112 ddt_enter(ddt);
2113 freedde = dde = ddt_lookup(ddt, bp, B_TRUE);
2114 if (dde) {
2115 ddp = ddt_phys_select(dde, bp);
2116 if (ddp) {
2117 ddt_phys_decref(ddp);
2118 }
2119 }
2120 ddt_exit(ddt);
2121
2122 return (ZIO_PIPELINE_CONTINUE);
2123 }
2124
2125 /*
2126 * ==========================================================================
2127 * Allocate and free blocks
2128 * ==========================================================================
2129 */
2130 static int
2131 zio_dva_allocate(zio_t *zio)
2132 {
2133 spa_t *spa = zio->io_spa;
2134 metaslab_class_t *mc = spa_normal_class(spa);
2135 blkptr_t *bp = zio->io_bp;
2136 int error;
2137 int flags = 0;
2138
2139 if (zio->io_gang_leader == NULL) {
2140 ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
2141 zio->io_gang_leader = zio;
2142 }
2143
2144 ASSERT(BP_IS_HOLE(bp));
2145 ASSERT3U(BP_GET_NDVAS(bp), ==, 0);
2146 ASSERT3U(zio->io_prop.zp_copies, >, 0);
2147 ASSERT3U(zio->io_prop.zp_copies, <=, spa_max_replication(spa));
2148 ASSERT3U(zio->io_size, ==, BP_GET_PSIZE(bp));
2149
2150 /*
2151 * The dump device does not support gang blocks so allocation on
2152 * behalf of the dump device (i.e. ZIO_FLAG_NODATA) must avoid
2153 * the "fast" gang feature.
2154 */
2155 flags |= (zio->io_flags & ZIO_FLAG_NODATA) ? METASLAB_GANG_AVOID : 0;
2156 flags |= (zio->io_flags & ZIO_FLAG_GANG_CHILD) ?
2157 METASLAB_GANG_CHILD : 0;
2158 error = metaslab_alloc(spa, mc, zio->io_size, bp,
2159 zio->io_prop.zp_copies, zio->io_txg, NULL, flags);
2160
2161 if (error) {
2162 spa_dbgmsg(spa, "%s: metaslab allocation failure: zio %p, "
2163 "size %llu, error %d", spa_name(spa), zio, zio->io_size,
2164 error);
2165 if (error == ENOSPC && zio->io_size > SPA_MINBLOCKSIZE)
2166 return (zio_write_gang_block(zio));
2167 zio->io_error = error;
2168 }
2169
2170 return (ZIO_PIPELINE_CONTINUE);
2171 }
2172
2173 static int
2174 zio_dva_free(zio_t *zio)
2175 {
2176 metaslab_free(zio->io_spa, zio->io_bp, zio->io_txg, B_FALSE);
2177
2178 return (ZIO_PIPELINE_CONTINUE);
2179 }
2180
2181 static int
2182 zio_dva_claim(zio_t *zio)
2183 {
2184 int error;
2185
2186 error = metaslab_claim(zio->io_spa, zio->io_bp, zio->io_txg);
2187 if (error)
2188 zio->io_error = error;
2189
2190 return (ZIO_PIPELINE_CONTINUE);
2191 }
2192
2193 /*
2194 * Undo an allocation. This is used by zio_done() when an I/O fails
2195 * and we want to give back the block we just allocated.
2196 * This handles both normal blocks and gang blocks.
2197 */
2198 static void
2199 zio_dva_unallocate(zio_t *zio, zio_gang_node_t *gn, blkptr_t *bp)
2200 {
2201 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp));
2202 ASSERT(zio->io_bp_override == NULL);
2203
2204 if (!BP_IS_HOLE(bp))
2205 metaslab_free(zio->io_spa, bp, bp->blk_birth, B_TRUE);
2206
2207 if (gn != NULL) {
2208 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
2209 zio_dva_unallocate(zio, gn->gn_child[g],
2210 &gn->gn_gbh->zg_blkptr[g]);
2211 }
2212 }
2213 }
2214
2215 /*
2216 * Try to allocate an intent log block. Return 0 on success, errno on failure.
2217 */
2218 int
2219 zio_alloc_zil(spa_t *spa, uint64_t txg, blkptr_t *new_bp, blkptr_t *old_bp,
2220 uint64_t size, boolean_t use_slog)
2221 {
2222 int error = 1;
2223
2224 ASSERT(txg > spa_syncing_txg(spa));
2225
2226 /*
2227 * ZIL blocks are always contiguous (i.e. not gang blocks) so we
2228 * set the METASLAB_GANG_AVOID flag so that they don't "fast gang"
2229 * when allocating them.
2230 */
2231 if (use_slog) {
2232 error = metaslab_alloc(spa, spa_log_class(spa), size,
2233 new_bp, 1, txg, old_bp,
2234 METASLAB_HINTBP_AVOID | METASLAB_GANG_AVOID);
2235 }
2236
2237 if (error) {
2238 error = metaslab_alloc(spa, spa_normal_class(spa), size,
2239 new_bp, 1, txg, old_bp,
2240 METASLAB_HINTBP_AVOID | METASLAB_GANG_AVOID);
2241 }
2242
2243 if (error == 0) {
2244 BP_SET_LSIZE(new_bp, size);
2245 BP_SET_PSIZE(new_bp, size);
2246 BP_SET_COMPRESS(new_bp, ZIO_COMPRESS_OFF);
2247 BP_SET_CHECKSUM(new_bp,
2248 spa_version(spa) >= SPA_VERSION_SLIM_ZIL
2249 ? ZIO_CHECKSUM_ZILOG2 : ZIO_CHECKSUM_ZILOG);
2250 BP_SET_TYPE(new_bp, DMU_OT_INTENT_LOG);
2251 BP_SET_LEVEL(new_bp, 0);
2252 BP_SET_DEDUP(new_bp, 0);
2253 BP_SET_BYTEORDER(new_bp, ZFS_HOST_BYTEORDER);
2254 }
2255
2256 return (error);
2257 }
2258
2259 /*
2260 * Free an intent log block.
2261 */
2262 void
2263 zio_free_zil(spa_t *spa, uint64_t txg, blkptr_t *bp)
2264 {
2265 ASSERT(BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG);
2266 ASSERT(!BP_IS_GANG(bp));
2267
2268 zio_free(spa, txg, bp);
2269 }
2270
2271 /*
2272 * ==========================================================================
2273 * Read and write to physical devices
2274 * ==========================================================================
2275 */
2276 static int
2277 zio_vdev_io_start(zio_t *zio)
2278 {
2279 vdev_t *vd = zio->io_vd;
2280 uint64_t align;
2281 spa_t *spa = zio->io_spa;
2282
2283 ASSERT(zio->io_error == 0);
2284 ASSERT(zio->io_child_error[ZIO_CHILD_VDEV] == 0);
2285
2286 if (vd == NULL) {
2287 if (!(zio->io_flags & ZIO_FLAG_CONFIG_WRITER))
2288 spa_config_enter(spa, SCL_ZIO, zio, RW_READER);
2289
2290 /*
2291 * The mirror_ops handle multiple DVAs in a single BP.
2292 */
2293 return (vdev_mirror_ops.vdev_op_io_start(zio));
2294 }
2295
2296 /*
2297 * We keep track of time-sensitive I/Os so that the scan thread
2298 * can quickly react to certain workloads. In particular, we care
2299 * about non-scrubbing, top-level reads and writes with the following
2300 * characteristics:
2301 * - synchronous writes of user data to non-slog devices
2302 * - any reads of user data
2303 * When these conditions are met, adjust the timestamp of spa_last_io
2304 * which allows the scan thread to adjust its workload accordingly.
2305 */
2306 if (!(zio->io_flags & ZIO_FLAG_SCAN_THREAD) && zio->io_bp != NULL &&
2307 vd == vd->vdev_top && !vd->vdev_islog &&
2308 zio->io_bookmark.zb_objset != DMU_META_OBJSET &&
2309 zio->io_txg != spa_syncing_txg(spa)) {
2310 uint64_t old = spa->spa_last_io;
2311 uint64_t new = ddi_get_lbolt64();
2312 if (old != new)
2313 (void) atomic_cas_64(&spa->spa_last_io, old, new);
2314 }
2315
2316 align = 1ULL << vd->vdev_top->vdev_ashift;
2317
2318 if (P2PHASE(zio->io_size, align) != 0) {
2319 uint64_t asize = P2ROUNDUP(zio->io_size, align);
2320 char *abuf = zio_buf_alloc(asize);
2321 ASSERT(vd == vd->vdev_top);
2322 if (zio->io_type == ZIO_TYPE_WRITE) {
2323 bcopy(zio->io_data, abuf, zio->io_size);
2324 bzero(abuf + zio->io_size, asize - zio->io_size);
2325 }
2326 zio_push_transform(zio, abuf, asize, asize, zio_subblock);
2327 }
2328
2329 ASSERT(P2PHASE(zio->io_offset, align) == 0);
2330 ASSERT(P2PHASE(zio->io_size, align) == 0);
2331 VERIFY(zio->io_type != ZIO_TYPE_WRITE || spa_writeable(spa));
2332
2333 /*
2334 * If this is a repair I/O, and there's no self-healing involved --
2335 * that is, we're just resilvering what we expect to resilver --
2336 * then don't do the I/O unless zio's txg is actually in vd's DTL.
2337 * This prevents spurious resilvering with nested replication.
2338 * For example, given a mirror of mirrors, (A+B)+(C+D), if only
2339 * A is out of date, we'll read from C+D, then use the data to
2340 * resilver A+B -- but we don't actually want to resilver B, just A.
2341 * The top-level mirror has no way to know this, so instead we just
2342 * discard unnecessary repairs as we work our way down the vdev tree.
2343 * The same logic applies to any form of nested replication:
2344 * ditto + mirror, RAID-Z + replacing, etc. This covers them all.
2345 */
2346 if ((zio->io_flags & ZIO_FLAG_IO_REPAIR) &&
2347 !(zio->io_flags & ZIO_FLAG_SELF_HEAL) &&
2348 zio->io_txg != 0 && /* not a delegated i/o */
2349 !vdev_dtl_contains(vd, DTL_PARTIAL, zio->io_txg, 1)) {
2350 ASSERT(zio->io_type == ZIO_TYPE_WRITE);
2351 zio_vdev_io_bypass(zio);
2352 return (ZIO_PIPELINE_CONTINUE);
2353 }
2354
2355 if (vd->vdev_ops->vdev_op_leaf &&
2356 (zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE)) {
2357
2358 if (zio->io_type == ZIO_TYPE_READ && vdev_cache_read(zio) == 0)
2359 return (ZIO_PIPELINE_CONTINUE);
2360
2361 if ((zio = vdev_queue_io(zio)) == NULL)
2362 return (ZIO_PIPELINE_STOP);
2363
2364 if (!vdev_accessible(vd, zio)) {
2365 zio->io_error = ENXIO;
2366 zio_interrupt(zio);
2367 return (ZIO_PIPELINE_STOP);
2368 }
2369 }
2370
2371 return (vd->vdev_ops->vdev_op_io_start(zio));
2372 }
2373
2374 static int
2375 zio_vdev_io_done(zio_t *zio)
2376 {
2377 vdev_t *vd = zio->io_vd;
2378 vdev_ops_t *ops = vd ? vd->vdev_ops : &vdev_mirror_ops;
2379 boolean_t unexpected_error = B_FALSE;
2380
2381 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE))
2382 return (ZIO_PIPELINE_STOP);
2383
2384 ASSERT(zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE);
2385
2386 if (vd != NULL && vd->vdev_ops->vdev_op_leaf) {
2387
2388 vdev_queue_io_done(zio);
2389
2390 if (zio->io_type == ZIO_TYPE_WRITE)
2391 vdev_cache_write(zio);
2392
2393 if (zio_injection_enabled && zio->io_error == 0)
2394 zio->io_error = zio_handle_device_injection(vd,
2395 zio, EIO);
2396
2397 if (zio_injection_enabled && zio->io_error == 0)
2398 zio->io_error = zio_handle_label_injection(zio, EIO);
2399
2400 if (zio->io_error) {
2401 if (!vdev_accessible(vd, zio)) {
2402 zio->io_error = ENXIO;
2403 } else {
2404 unexpected_error = B_TRUE;
2405 }
2406 }
2407 }
2408
2409 ops->vdev_op_io_done(zio);
2410
2411 if (unexpected_error)
2412 VERIFY(vdev_probe(vd, zio) == NULL);
2413
2414 return (ZIO_PIPELINE_CONTINUE);
2415 }
2416
2417 /*
2418 * For non-raidz ZIOs, we can just copy aside the bad data read from the
2419 * disk, and use that to finish the checksum ereport later.
2420 */
2421 static void
2422 zio_vsd_default_cksum_finish(zio_cksum_report_t *zcr,
2423 const void *good_buf)
2424 {
2425 /* no processing needed */
2426 zfs_ereport_finish_checksum(zcr, good_buf, zcr->zcr_cbdata, B_FALSE);
2427 }
2428
2429 /*ARGSUSED*/
2430 void
2431 zio_vsd_default_cksum_report(zio_t *zio, zio_cksum_report_t *zcr, void *ignored)
2432 {
2433 void *buf = zio_buf_alloc(zio->io_size);
2434
2435 bcopy(zio->io_data, buf, zio->io_size);
2436
2437 zcr->zcr_cbinfo = zio->io_size;
2438 zcr->zcr_cbdata = buf;
2439 zcr->zcr_finish = zio_vsd_default_cksum_finish;
2440 zcr->zcr_free = zio_buf_free;
2441 }
2442
2443 static int
2444 zio_vdev_io_assess(zio_t *zio)
2445 {
2446 vdev_t *vd = zio->io_vd;
2447
2448 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE))
2449 return (ZIO_PIPELINE_STOP);
2450
2451 if (vd == NULL && !(zio->io_flags & ZIO_FLAG_CONFIG_WRITER))
2452 spa_config_exit(zio->io_spa, SCL_ZIO, zio);
2453
2454 if (zio->io_vsd != NULL) {
2455 zio->io_vsd_ops->vsd_free(zio);
2456 zio->io_vsd = NULL;
2457 }
2458
2459 if (zio_injection_enabled && zio->io_error == 0)
2460 zio->io_error = zio_handle_fault_injection(zio, EIO);
2461
2462 /*
2463 * If the I/O failed, determine whether we should attempt to retry it.
2464 *
2465 * On retry, we cut in line in the issue queue, since we don't want
2466 * compression/checksumming/etc. work to prevent our (cheap) IO reissue.
2467 */
2468 if (zio->io_error && vd == NULL &&
2469 !(zio->io_flags & (ZIO_FLAG_DONT_RETRY | ZIO_FLAG_IO_RETRY))) {
2470 ASSERT(!(zio->io_flags & ZIO_FLAG_DONT_QUEUE)); /* not a leaf */
2471 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_BYPASS)); /* not a leaf */
2472 zio->io_error = 0;
2473 zio->io_flags |= ZIO_FLAG_IO_RETRY |
2474 ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE;
2475 zio->io_stage = ZIO_STAGE_VDEV_IO_START >> 1;
2476 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE,
2477 zio_requeue_io_start_cut_in_line);
2478 return (ZIO_PIPELINE_STOP);
2479 }
2480
2481 /*
2482 * If we got an error on a leaf device, convert it to ENXIO
2483 * if the device is not accessible at all.
2484 */
2485 if (zio->io_error && vd != NULL && vd->vdev_ops->vdev_op_leaf &&
2486 !vdev_accessible(vd, zio))
2487 zio->io_error = ENXIO;
2488
2489 /*
2490 * If we can't write to an interior vdev (mirror or RAID-Z),
2491 * set vdev_cant_write so that we stop trying to allocate from it.
2492 */
2493 if (zio->io_error == ENXIO && zio->io_type == ZIO_TYPE_WRITE &&
2494 vd != NULL && !vd->vdev_ops->vdev_op_leaf)
2495 vd->vdev_cant_write = B_TRUE;
2496
2497 if (zio->io_error)
2498 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
2499
2500 return (ZIO_PIPELINE_CONTINUE);
2501 }
2502
2503 void
2504 zio_vdev_io_reissue(zio_t *zio)
2505 {
2506 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START);
2507 ASSERT(zio->io_error == 0);
2508
2509 zio->io_stage >>= 1;
2510 }
2511
2512 void
2513 zio_vdev_io_redone(zio_t *zio)
2514 {
2515 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_DONE);
2516
2517 zio->io_stage >>= 1;
2518 }
2519
2520 void
2521 zio_vdev_io_bypass(zio_t *zio)
2522 {
2523 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START);
2524 ASSERT(zio->io_error == 0);
2525
2526 zio->io_flags |= ZIO_FLAG_IO_BYPASS;
2527 zio->io_stage = ZIO_STAGE_VDEV_IO_ASSESS >> 1;
2528 }
2529
2530 /*
2531 * ==========================================================================
2532 * Generate and verify checksums
2533 * ==========================================================================
2534 */
2535 static int
2536 zio_checksum_generate(zio_t *zio)
2537 {
2538 blkptr_t *bp = zio->io_bp;
2539 enum zio_checksum checksum;
2540
2541 if (bp == NULL) {
2542 /*
2543 * This is zio_write_phys().
2544 * We're either generating a label checksum, or none at all.
2545 */
2546 checksum = zio->io_prop.zp_checksum;
2547
2548 if (checksum == ZIO_CHECKSUM_OFF)
2549 return (ZIO_PIPELINE_CONTINUE);
2550
2551 ASSERT(checksum == ZIO_CHECKSUM_LABEL);
2552 } else {
2553 if (BP_IS_GANG(bp) && zio->io_child_type == ZIO_CHILD_GANG) {
2554 ASSERT(!IO_IS_ALLOCATING(zio));
2555 checksum = ZIO_CHECKSUM_GANG_HEADER;
2556 } else {
2557 checksum = BP_GET_CHECKSUM(bp);
2558 }
2559 }
2560
2561 zio_checksum_compute(zio, checksum, zio->io_data, zio->io_size);
2562
2563 return (ZIO_PIPELINE_CONTINUE);
2564 }
2565
2566 static int
2567 zio_checksum_verify(zio_t *zio)
2568 {
2569 zio_bad_cksum_t info;
2570 blkptr_t *bp = zio->io_bp;
2571 int error;
2572
2573 ASSERT(zio->io_vd != NULL);
2574
2575 if (bp == NULL) {
2576 /*
2577 * This is zio_read_phys().
2578 * We're either verifying a label checksum, or nothing at all.
2579 */
2580 if (zio->io_prop.zp_checksum == ZIO_CHECKSUM_OFF)
2581 return (ZIO_PIPELINE_CONTINUE);
2582
2583 ASSERT(zio->io_prop.zp_checksum == ZIO_CHECKSUM_LABEL);
2584 }
2585
2586 if ((error = zio_checksum_error(zio, &info)) != 0) {
2587 zio->io_error = error;
2588 if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) {
2589 zfs_ereport_start_checksum(zio->io_spa,
2590 zio->io_vd, zio, zio->io_offset,
2591 zio->io_size, NULL, &info);
2592 }
2593 }
2594
2595 return (ZIO_PIPELINE_CONTINUE);
2596 }
2597
2598 /*
2599 * Called by RAID-Z to ensure we don't compute the checksum twice.
2600 */
2601 void
2602 zio_checksum_verified(zio_t *zio)
2603 {
2604 zio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY;
2605 }
2606
2607 /*
2608 * ==========================================================================
2609 * Error rank. Error are ranked in the order 0, ENXIO, ECKSUM, EIO, other.
2610 * An error of 0 indictes success. ENXIO indicates whole-device failure,
2611 * which may be transient (e.g. unplugged) or permament. ECKSUM and EIO
2612 * indicate errors that are specific to one I/O, and most likely permanent.
2613 * Any other error is presumed to be worse because we weren't expecting it.
2614 * ==========================================================================
2615 */
2616 int
2617 zio_worst_error(int e1, int e2)
2618 {
2619 static int zio_error_rank[] = { 0, ENXIO, ECKSUM, EIO };
2620 int r1, r2;
2621
2622 for (r1 = 0; r1 < sizeof (zio_error_rank) / sizeof (int); r1++)
2623 if (e1 == zio_error_rank[r1])
2624 break;
2625
2626 for (r2 = 0; r2 < sizeof (zio_error_rank) / sizeof (int); r2++)
2627 if (e2 == zio_error_rank[r2])
2628 break;
2629
2630 return (r1 > r2 ? e1 : e2);
2631 }
2632
2633 /*
2634 * ==========================================================================
2635 * I/O completion
2636 * ==========================================================================
2637 */
2638 static int
2639 zio_ready(zio_t *zio)
2640 {
2641 blkptr_t *bp = zio->io_bp;
2642 zio_t *pio, *pio_next;
2643
2644 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) ||
2645 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_READY))
2646 return (ZIO_PIPELINE_STOP);
2647
2648 if (zio->io_ready) {
2649 ASSERT(IO_IS_ALLOCATING(zio));
2650 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp));
2651 ASSERT(zio->io_children[ZIO_CHILD_GANG][ZIO_WAIT_READY] == 0);
2652
2653 zio->io_ready(zio);
2654 }
2655
2656 if (bp != NULL && bp != &zio->io_bp_copy)
2657 zio->io_bp_copy = *bp;
2658
2659 if (zio->io_error)
2660 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
2661
2662 mutex_enter(&zio->io_lock);
2663 zio->io_state[ZIO_WAIT_READY] = 1;
2664 pio = zio_walk_parents(zio);
2665 mutex_exit(&zio->io_lock);
2666
2667 /*
2668 * As we notify zio's parents, new parents could be added.
2669 * New parents go to the head of zio's io_parent_list, however,
2670 * so we will (correctly) not notify them. The remainder of zio's
2671 * io_parent_list, from 'pio_next' onward, cannot change because
2672 * all parents must wait for us to be done before they can be done.
2673 */
2674 for (; pio != NULL; pio = pio_next) {
2675 pio_next = zio_walk_parents(zio);
2676 zio_notify_parent(pio, zio, ZIO_WAIT_READY);
2677 }
2678
2679 if (zio->io_flags & ZIO_FLAG_NODATA) {
2680 if (BP_IS_GANG(bp)) {
2681 zio->io_flags &= ~ZIO_FLAG_NODATA;
2682 } else {
2683 ASSERT((uintptr_t)zio->io_data < SPA_MAXBLOCKSIZE);
2684 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES;
2685 }
2686 }
2687
2688 if (zio_injection_enabled &&
2689 zio->io_spa->spa_syncing_txg == zio->io_txg)
2690 zio_handle_ignored_writes(zio);
2691
2692 return (ZIO_PIPELINE_CONTINUE);
2693 }
2694
2695 static int
2696 zio_done(zio_t *zio)
2697 {
2698 spa_t *spa = zio->io_spa;
2699 zio_t *lio = zio->io_logical;
2700 blkptr_t *bp = zio->io_bp;
2701 vdev_t *vd = zio->io_vd;
2702 uint64_t psize = zio->io_size;
2703 zio_t *pio, *pio_next;
2704
2705 /*
2706 * If our children haven't all completed,
2707 * wait for them and then repeat this pipeline stage.
2708 */
2709 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE) ||
2710 zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE) ||
2711 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE) ||
2712 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_DONE))
2713 return (ZIO_PIPELINE_STOP);
2714
2715 for (int c = 0; c < ZIO_CHILD_TYPES; c++)
2716 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
2717 ASSERT(zio->io_children[c][w] == 0);
2718
2719 if (bp != NULL) {
2720 ASSERT(bp->blk_pad[0] == 0);
2721 ASSERT(bp->blk_pad[1] == 0);
2722 ASSERT(bcmp(bp, &zio->io_bp_copy, sizeof (blkptr_t)) == 0 ||
2723 (bp == zio_unique_parent(zio)->io_bp));
2724 if (zio->io_type == ZIO_TYPE_WRITE && !BP_IS_HOLE(bp) &&
2725 zio->io_bp_override == NULL &&
2726 !(zio->io_flags & ZIO_FLAG_IO_REPAIR)) {
2727 ASSERT(!BP_SHOULD_BYTESWAP(bp));
2728 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(bp));
2729 ASSERT(BP_COUNT_GANG(bp) == 0 ||
2730 (BP_COUNT_GANG(bp) == BP_GET_NDVAS(bp)));
2731 }
2732 }
2733
2734 /*
2735 * If there were child vdev/gang/ddt errors, they apply to us now.
2736 */
2737 zio_inherit_child_errors(zio, ZIO_CHILD_VDEV);
2738 zio_inherit_child_errors(zio, ZIO_CHILD_GANG);
2739 zio_inherit_child_errors(zio, ZIO_CHILD_DDT);
2740
2741 /*
2742 * If the I/O on the transformed data was successful, generate any
2743 * checksum reports now while we still have the transformed data.
2744 */
2745 if (zio->io_error == 0) {
2746 while (zio->io_cksum_report != NULL) {
2747 zio_cksum_report_t *zcr = zio->io_cksum_report;
2748 uint64_t align = zcr->zcr_align;
2749 uint64_t asize = P2ROUNDUP(psize, align);
2750 char *abuf = zio->io_data;
2751
2752 if (asize != psize) {
2753 abuf = zio_buf_alloc(asize);
2754 bcopy(zio->io_data, abuf, psize);
2755 bzero(abuf + psize, asize - psize);
2756 }
2757
2758 zio->io_cksum_report = zcr->zcr_next;
2759 zcr->zcr_next = NULL;
2760 zcr->zcr_finish(zcr, abuf);
2761 zfs_ereport_free_checksum(zcr);
2762
2763 if (asize != psize)
2764 zio_buf_free(abuf, asize);
2765 }
2766 }
2767
2768 zio_pop_transforms(zio); /* note: may set zio->io_error */
2769
2770 vdev_stat_update(zio, psize);
2771
2772 if (zio->io_error) {
2773 /*
2774 * If this I/O is attached to a particular vdev,
2775 * generate an error message describing the I/O failure
2776 * at the block level. We ignore these errors if the
2777 * device is currently unavailable.
2778 */
2779 if (zio->io_error != ECKSUM && vd != NULL && !vdev_is_dead(vd))
2780 zfs_ereport_post(FM_EREPORT_ZFS_IO, spa, vd, zio, 0, 0);
2781
2782 if ((zio->io_error == EIO || !(zio->io_flags &
2783 (ZIO_FLAG_SPECULATIVE | ZIO_FLAG_DONT_PROPAGATE))) &&
2784 zio == lio) {
2785 /*
2786 * For logical I/O requests, tell the SPA to log the
2787 * error and generate a logical data ereport.
2788 */
2789 spa_log_error(spa, zio);
2790 zfs_ereport_post(FM_EREPORT_ZFS_DATA, spa, NULL, zio,
2791 0, 0);
2792 }
2793 }
2794
2795 if (zio->io_error && zio == lio) {
2796 /*
2797 * Determine whether zio should be reexecuted. This will
2798 * propagate all the way to the root via zio_notify_parent().
2799 */
2800 ASSERT(vd == NULL && bp != NULL);
2801 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
2802
2803 if (IO_IS_ALLOCATING(zio) &&
2804 !(zio->io_flags & ZIO_FLAG_CANFAIL)) {
2805 if (zio->io_error != ENOSPC)
2806 zio->io_reexecute |= ZIO_REEXECUTE_NOW;
2807 else
2808 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
2809 }
2810
2811 if ((zio->io_type == ZIO_TYPE_READ ||
2812 zio->io_type == ZIO_TYPE_FREE) &&
2813 !(zio->io_flags & ZIO_FLAG_SCAN_THREAD) &&
2814 zio->io_error == ENXIO &&
2815 spa_load_state(spa) == SPA_LOAD_NONE &&
2816 spa_get_failmode(spa) != ZIO_FAILURE_MODE_CONTINUE)
2817 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
2818
2819 if (!(zio->io_flags & ZIO_FLAG_CANFAIL) && !zio->io_reexecute)
2820 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
2821
2822 /*
2823 * Here is a possibly good place to attempt to do
2824 * either combinatorial reconstruction or error correction
2825 * based on checksums. It also might be a good place
2826 * to send out preliminary ereports before we suspend
2827 * processing.
2828 */
2829 }
2830
2831 /*
2832 * If there were logical child errors, they apply to us now.
2833 * We defer this until now to avoid conflating logical child
2834 * errors with errors that happened to the zio itself when
2835 * updating vdev stats and reporting FMA events above.
2836 */
2837 zio_inherit_child_errors(zio, ZIO_CHILD_LOGICAL);
2838
2839 if ((zio->io_error || zio->io_reexecute) &&
2840 IO_IS_ALLOCATING(zio) && zio->io_gang_leader == zio &&
2841 !(zio->io_flags & ZIO_FLAG_IO_REWRITE))
2842 zio_dva_unallocate(zio, zio->io_gang_tree, bp);
2843
2844 zio_gang_tree_free(&zio->io_gang_tree);
2845
2846 /*
2847 * Godfather I/Os should never suspend.
2848 */
2849 if ((zio->io_flags & ZIO_FLAG_GODFATHER) &&
2850 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND))
2851 zio->io_reexecute = 0;
2852
2853 if (zio->io_reexecute) {
2854 /*
2855 * This is a logical I/O that wants to reexecute.
2856 *
2857 * Reexecute is top-down. When an i/o fails, if it's not
2858 * the root, it simply notifies its parent and sticks around.
2859 * The parent, seeing that it still has children in zio_done(),
2860 * does the same. This percolates all the way up to the root.
2861 * The root i/o will reexecute or suspend the entire tree.
2862 *
2863 * This approach ensures that zio_reexecute() honors
2864 * all the original i/o dependency relationships, e.g.
2865 * parents not executing until children are ready.
2866 */
2867 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
2868
2869 zio->io_gang_leader = NULL;
2870
2871 mutex_enter(&zio->io_lock);
2872 zio->io_state[ZIO_WAIT_DONE] = 1;
2873 mutex_exit(&zio->io_lock);
2874
2875 /*
2876 * "The Godfather" I/O monitors its children but is
2877 * not a true parent to them. It will track them through
2878 * the pipeline but severs its ties whenever they get into
2879 * trouble (e.g. suspended). This allows "The Godfather"
2880 * I/O to return status without blocking.
2881 */
2882 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) {
2883 zio_link_t *zl = zio->io_walk_link;
2884 pio_next = zio_walk_parents(zio);
2885
2886 if ((pio->io_flags & ZIO_FLAG_GODFATHER) &&
2887 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND)) {
2888 zio_remove_child(pio, zio, zl);
2889 zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
2890 }
2891 }
2892
2893 if ((pio = zio_unique_parent(zio)) != NULL) {
2894 /*
2895 * We're not a root i/o, so there's nothing to do
2896 * but notify our parent. Don't propagate errors
2897 * upward since we haven't permanently failed yet.
2898 */
2899 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER));
2900 zio->io_flags |= ZIO_FLAG_DONT_PROPAGATE;
2901 zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
2902 } else if (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND) {
2903 /*
2904 * We'd fail again if we reexecuted now, so suspend
2905 * until conditions improve (e.g. device comes online).
2906 */
2907 zio_suspend(spa, zio);
2908 } else {
2909 /*
2910 * Reexecution is potentially a huge amount of work.
2911 * Hand it off to the otherwise-unused claim taskq.
2912 */
2913 ASSERT(zio->io_tqent.tqent_next == NULL);
2914 (void) taskq_dispatch_ent(
2915 spa->spa_zio_taskq[ZIO_TYPE_CLAIM][ZIO_TASKQ_ISSUE],
2916 (task_func_t *)zio_reexecute, zio, 0,
2917 &zio->io_tqent);
2918 }
2919 return (ZIO_PIPELINE_STOP);
2920 }
2921
2922 ASSERT(zio->io_child_count == 0);
2923 ASSERT(zio->io_reexecute == 0);
2924 ASSERT(zio->io_error == 0 || (zio->io_flags & ZIO_FLAG_CANFAIL));
2925
2926 /*
2927 * Report any checksum errors, since the I/O is complete.
2928 */
2929 while (zio->io_cksum_report != NULL) {
2930 zio_cksum_report_t *zcr = zio->io_cksum_report;
2931 zio->io_cksum_report = zcr->zcr_next;
2932 zcr->zcr_next = NULL;
2933 zcr->zcr_finish(zcr, NULL);
2934 zfs_ereport_free_checksum(zcr);
2935 }
2936
2937 /*
2938 * It is the responsibility of the done callback to ensure that this
2939 * particular zio is no longer discoverable for adoption, and as
2940 * such, cannot acquire any new parents.
2941 */
2942 if (zio->io_done)
2943 zio->io_done(zio);
2944
2945 mutex_enter(&zio->io_lock);
2946 zio->io_state[ZIO_WAIT_DONE] = 1;
2947 mutex_exit(&zio->io_lock);
2948
2949 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) {
2950 zio_link_t *zl = zio->io_walk_link;
2951 pio_next = zio_walk_parents(zio);
2952 zio_remove_child(pio, zio, zl);
2953 zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
2954 }
2955
2956 if (zio->io_waiter != NULL) {
2957 mutex_enter(&zio->io_lock);
2958 zio->io_executor = NULL;
2959 cv_broadcast(&zio->io_cv);
2960 mutex_exit(&zio->io_lock);
2961 } else {
2962 zio_destroy(zio);
2963 }
2964
2965 return (ZIO_PIPELINE_STOP);
2966 }
2967
2968 /*
2969 * ==========================================================================
2970 * I/O pipeline definition
2971 * ==========================================================================
2972 */
2973 static zio_pipe_stage_t *zio_pipeline[] = {
2974 NULL,
2975 zio_read_bp_init,
2976 zio_free_bp_init,
2977 zio_issue_async,
2978 zio_write_bp_init,
2979 zio_checksum_generate,
2980 zio_ddt_read_start,
2981 zio_ddt_read_done,
2982 zio_ddt_write,
2983 zio_ddt_free,
2984 zio_gang_assemble,
2985 zio_gang_issue,
2986 zio_dva_allocate,
2987 zio_dva_free,
2988 zio_dva_claim,
2989 zio_ready,
2990 zio_vdev_io_start,
2991 zio_vdev_io_done,
2992 zio_vdev_io_assess,
2993 zio_checksum_verify,
2994 zio_done
2995 };