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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 */
24
25 #include <sys/zfs_context.h>
26 #include <sys/fm/fs/zfs.h>
27 #include <sys/spa.h>
28 #include <sys/txg.h>
29 #include <sys/spa_impl.h>
30 #include <sys/vdev_impl.h>
31 #include <sys/zio_impl.h>
32 #include <sys/zio_compress.h>
33 #include <sys/zio_checksum.h>
34 #include <sys/dmu_objset.h>
35 #include <sys/arc.h>
36 #include <sys/ddt.h>
37
38 /*
39 * ==========================================================================
40 * I/O priority table
41 * ==========================================================================
42 */
43 uint8_t zio_priority_table[ZIO_PRIORITY_TABLE_SIZE] = {
44 0, /* ZIO_PRIORITY_NOW */
45 0, /* ZIO_PRIORITY_SYNC_READ */
46 0, /* ZIO_PRIORITY_SYNC_WRITE */
47 0, /* ZIO_PRIORITY_LOG_WRITE */
48 1, /* ZIO_PRIORITY_CACHE_FILL */
49 1, /* ZIO_PRIORITY_AGG */
50 4, /* ZIO_PRIORITY_FREE */
51 4, /* ZIO_PRIORITY_ASYNC_WRITE */
52 6, /* ZIO_PRIORITY_ASYNC_READ */
53 10, /* ZIO_PRIORITY_RESILVER */
54 20, /* ZIO_PRIORITY_SCRUB */
55 2, /* ZIO_PRIORITY_DDT_PREFETCH */
56 };
57
58 /*
59 * ==========================================================================
60 * I/O type descriptions
61 * ==========================================================================
62 */
63 char *zio_type_name[ZIO_TYPES] = {
64 "zio_null", "zio_read", "zio_write", "zio_free", "zio_claim",
65 "zio_ioctl"
66 };
67
68 /*
69 * ==========================================================================
70 * I/O kmem caches
71 * ==========================================================================
72 */
73 kmem_cache_t *zio_cache;
74 kmem_cache_t *zio_link_cache;
75 kmem_cache_t *zio_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
76 kmem_cache_t *zio_data_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
77
78 #ifdef _KERNEL
79 extern vmem_t *zio_alloc_arena;
80 #endif
81
82 /*
83 * An allocating zio is one that either currently has the DVA allocate
84 * stage set or will have it later in its lifetime.
85 */
86 #define IO_IS_ALLOCATING(zio) ((zio)->io_orig_pipeline & ZIO_STAGE_DVA_ALLOCATE)
87
88 boolean_t zio_requeue_io_start_cut_in_line = B_TRUE;
89
90 #ifdef ZFS_DEBUG
91 int zio_buf_debug_limit = 16384;
92 #else
93 int zio_buf_debug_limit = 0;
94 #endif
95
96 void
97 zio_init(void)
98 {
99 size_t c;
100 vmem_t *data_alloc_arena = NULL;
101
102 #ifdef _KERNEL
103 data_alloc_arena = zio_alloc_arena;
104 #endif
105 zio_cache = kmem_cache_create("zio_cache",
106 sizeof (zio_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
107 zio_link_cache = kmem_cache_create("zio_link_cache",
108 sizeof (zio_link_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
109
110 /*
111 * For small buffers, we want a cache for each multiple of
112 * SPA_MINBLOCKSIZE. For medium-size buffers, we want a cache
113 * for each quarter-power of 2. For large buffers, we want
114 * a cache for each multiple of PAGESIZE.
115 */
116 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) {
117 size_t size = (c + 1) << SPA_MINBLOCKSHIFT;
118 size_t p2 = size;
119 size_t align = 0;
120
121 while (p2 & (p2 - 1))
122 p2 &= p2 - 1;
123
124 if (size <= 4 * SPA_MINBLOCKSIZE) {
125 align = SPA_MINBLOCKSIZE;
126 } else if (P2PHASE(size, PAGESIZE) == 0) {
127 align = PAGESIZE;
128 } else if (P2PHASE(size, p2 >> 2) == 0) {
129 align = p2 >> 2;
130 }
131
132 if (align != 0) {
133 char name[36];
134 (void) sprintf(name, "zio_buf_%lu", (ulong_t)size);
135 zio_buf_cache[c] = kmem_cache_create(name, size,
136 align, NULL, NULL, NULL, NULL, NULL,
137 size > zio_buf_debug_limit ? KMC_NODEBUG : 0);
138
139 (void) sprintf(name, "zio_data_buf_%lu", (ulong_t)size);
140 zio_data_buf_cache[c] = kmem_cache_create(name, size,
141 align, NULL, NULL, NULL, NULL, data_alloc_arena,
142 size > zio_buf_debug_limit ? KMC_NODEBUG : 0);
143 }
144 }
145
146 while (--c != 0) {
147 ASSERT(zio_buf_cache[c] != NULL);
148 if (zio_buf_cache[c - 1] == NULL)
149 zio_buf_cache[c - 1] = zio_buf_cache[c];
150
151 ASSERT(zio_data_buf_cache[c] != NULL);
152 if (zio_data_buf_cache[c - 1] == NULL)
153 zio_data_buf_cache[c - 1] = zio_data_buf_cache[c];
154 }
155
156 zio_inject_init();
157 }
158
159 void
160 zio_fini(void)
161 {
162 size_t c;
163 kmem_cache_t *last_cache = NULL;
164 kmem_cache_t *last_data_cache = NULL;
165
166 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) {
167 if (zio_buf_cache[c] != last_cache) {
168 last_cache = zio_buf_cache[c];
169 kmem_cache_destroy(zio_buf_cache[c]);
170 }
171 zio_buf_cache[c] = NULL;
172
173 if (zio_data_buf_cache[c] != last_data_cache) {
174 last_data_cache = zio_data_buf_cache[c];
175 kmem_cache_destroy(zio_data_buf_cache[c]);
176 }
177 zio_data_buf_cache[c] = NULL;
178 }
179
180 kmem_cache_destroy(zio_link_cache);
181 kmem_cache_destroy(zio_cache);
182
183 zio_inject_fini();
184 }
185
186 /*
187 * ==========================================================================
188 * Allocate and free I/O buffers
189 * ==========================================================================
190 */
191
192 /*
193 * Use zio_buf_alloc to allocate ZFS metadata. This data will appear in a
194 * crashdump if the kernel panics, so use it judiciously. Obviously, it's
195 * useful to inspect ZFS metadata, but if possible, we should avoid keeping
196 * excess / transient data in-core during a crashdump.
197 */
198 void *
199 zio_buf_alloc(size_t size)
200 {
201 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
202
203 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
204
205 return (kmem_cache_alloc(zio_buf_cache[c], KM_PUSHPAGE));
206 }
207
208 /*
209 * Use zio_data_buf_alloc to allocate data. The data will not appear in a
210 * crashdump if the kernel panics. This exists so that we will limit the amount
211 * of ZFS data that shows up in a kernel crashdump. (Thus reducing the amount
212 * of kernel heap dumped to disk when the kernel panics)
213 */
214 void *
215 zio_data_buf_alloc(size_t size)
216 {
217 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
218
219 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
220
221 return (kmem_cache_alloc(zio_data_buf_cache[c], KM_PUSHPAGE));
222 }
223
224 void
225 zio_buf_free(void *buf, size_t size)
226 {
227 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
228
229 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
230
231 kmem_cache_free(zio_buf_cache[c], buf);
232 }
233
234 void
235 zio_data_buf_free(void *buf, size_t size)
236 {
237 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
238
239 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
240
241 kmem_cache_free(zio_data_buf_cache[c], buf);
242 }
243
244 /*
245 * ==========================================================================
246 * Push and pop I/O transform buffers
247 * ==========================================================================
248 */
249 static void
250 zio_push_transform(zio_t *zio, void *data, uint64_t size, uint64_t bufsize,
251 zio_transform_func_t *transform)
252 {
253 zio_transform_t *zt = kmem_alloc(sizeof (zio_transform_t), KM_SLEEP);
254
255 zt->zt_orig_data = zio->io_data;
256 zt->zt_orig_size = zio->io_size;
257 zt->zt_bufsize = bufsize;
258 zt->zt_transform = transform;
259
260 zt->zt_next = zio->io_transform_stack;
261 zio->io_transform_stack = zt;
262
263 zio->io_data = data;
264 zio->io_size = size;
265 }
266
267 static void
268 zio_pop_transforms(zio_t *zio)
269 {
270 zio_transform_t *zt;
271
272 while ((zt = zio->io_transform_stack) != NULL) {
273 if (zt->zt_transform != NULL)
274 zt->zt_transform(zio,
275 zt->zt_orig_data, zt->zt_orig_size);
276
277 if (zt->zt_bufsize != 0)
278 zio_buf_free(zio->io_data, zt->zt_bufsize);
279
280 zio->io_data = zt->zt_orig_data;
281 zio->io_size = zt->zt_orig_size;
282 zio->io_transform_stack = zt->zt_next;
283
284 kmem_free(zt, sizeof (zio_transform_t));
285 }
286 }
287
288 /*
289 * ==========================================================================
290 * I/O transform callbacks for subblocks and decompression
291 * ==========================================================================
292 */
293 static void
294 zio_subblock(zio_t *zio, void *data, uint64_t size)
295 {
296 ASSERT(zio->io_size > size);
297
298 if (zio->io_type == ZIO_TYPE_READ)
299 bcopy(zio->io_data, data, size);
300 }
301
302 static void
303 zio_decompress(zio_t *zio, void *data, uint64_t size)
304 {
305 if (zio->io_error == 0 &&
306 zio_decompress_data(BP_GET_COMPRESS(zio->io_bp),
307 zio->io_data, data, zio->io_size, size) != 0)
308 zio->io_error = EIO;
309 }
310
311 /*
312 * ==========================================================================
313 * I/O parent/child relationships and pipeline interlocks
314 * ==========================================================================
315 */
316 /*
317 * NOTE - Callers to zio_walk_parents() and zio_walk_children must
318 * continue calling these functions until they return NULL.
319 * Otherwise, the next caller will pick up the list walk in
320 * some indeterminate state. (Otherwise every caller would
321 * have to pass in a cookie to keep the state represented by
322 * io_walk_link, which gets annoying.)
323 */
324 zio_t *
325 zio_walk_parents(zio_t *cio)
326 {
327 zio_link_t *zl = cio->io_walk_link;
328 list_t *pl = &cio->io_parent_list;
329
330 zl = (zl == NULL) ? list_head(pl) : list_next(pl, zl);
331 cio->io_walk_link = zl;
332
333 if (zl == NULL)
334 return (NULL);
335
336 ASSERT(zl->zl_child == cio);
337 return (zl->zl_parent);
338 }
339
340 zio_t *
341 zio_walk_children(zio_t *pio)
342 {
343 zio_link_t *zl = pio->io_walk_link;
344 list_t *cl = &pio->io_child_list;
345
346 zl = (zl == NULL) ? list_head(cl) : list_next(cl, zl);
347 pio->io_walk_link = zl;
348
349 if (zl == NULL)
350 return (NULL);
351
352 ASSERT(zl->zl_parent == pio);
353 return (zl->zl_child);
354 }
355
356 zio_t *
357 zio_unique_parent(zio_t *cio)
358 {
359 zio_t *pio = zio_walk_parents(cio);
360
361 VERIFY(zio_walk_parents(cio) == NULL);
362 return (pio);
363 }
364
365 void
366 zio_add_child(zio_t *pio, zio_t *cio)
367 {
368 zio_link_t *zl = kmem_cache_alloc(zio_link_cache, KM_SLEEP);
369
370 /*
371 * Logical I/Os can have logical, gang, or vdev children.
372 * Gang I/Os can have gang or vdev children.
373 * Vdev I/Os can only have vdev children.
374 * The following ASSERT captures all of these constraints.
375 */
376 ASSERT(cio->io_child_type <= pio->io_child_type);
377
378 zl->zl_parent = pio;
379 zl->zl_child = cio;
380
381 mutex_enter(&cio->io_lock);
382 mutex_enter(&pio->io_lock);
383
384 ASSERT(pio->io_state[ZIO_WAIT_DONE] == 0);
385
386 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
387 pio->io_children[cio->io_child_type][w] += !cio->io_state[w];
388
389 list_insert_head(&pio->io_child_list, zl);
390 list_insert_head(&cio->io_parent_list, zl);
391
392 pio->io_child_count++;
393 cio->io_parent_count++;
394
395 mutex_exit(&pio->io_lock);
396 mutex_exit(&cio->io_lock);
397 }
398
399 static void
400 zio_remove_child(zio_t *pio, zio_t *cio, zio_link_t *zl)
401 {
402 ASSERT(zl->zl_parent == pio);
403 ASSERT(zl->zl_child == cio);
404
405 mutex_enter(&cio->io_lock);
406 mutex_enter(&pio->io_lock);
407
408 list_remove(&pio->io_child_list, zl);
409 list_remove(&cio->io_parent_list, zl);
410
411 pio->io_child_count--;
412 cio->io_parent_count--;
413
414 mutex_exit(&pio->io_lock);
415 mutex_exit(&cio->io_lock);
416
417 kmem_cache_free(zio_link_cache, zl);
418 }
419
420 static boolean_t
421 zio_wait_for_children(zio_t *zio, enum zio_child child, enum zio_wait_type wait)
422 {
423 uint64_t *countp = &zio->io_children[child][wait];
424 boolean_t waiting = B_FALSE;
425
426 mutex_enter(&zio->io_lock);
427 ASSERT(zio->io_stall == NULL);
428 if (*countp != 0) {
429 zio->io_stage >>= 1;
430 zio->io_stall = countp;
431 waiting = B_TRUE;
432 }
433 mutex_exit(&zio->io_lock);
434
435 return (waiting);
436 }
437
438 static void
439 zio_notify_parent(zio_t *pio, zio_t *zio, enum zio_wait_type wait)
440 {
441 uint64_t *countp = &pio->io_children[zio->io_child_type][wait];
442 int *errorp = &pio->io_child_error[zio->io_child_type];
443
444 mutex_enter(&pio->io_lock);
445 if (zio->io_error && !(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE))
446 *errorp = zio_worst_error(*errorp, zio->io_error);
447 pio->io_reexecute |= zio->io_reexecute;
448 ASSERT3U(*countp, >, 0);
449 if (--*countp == 0 && pio->io_stall == countp) {
450 pio->io_stall = NULL;
451 mutex_exit(&pio->io_lock);
452 zio_execute(pio);
453 } else {
454 mutex_exit(&pio->io_lock);
455 }
456 }
457
458 static void
459 zio_inherit_child_errors(zio_t *zio, enum zio_child c)
460 {
461 if (zio->io_child_error[c] != 0 && zio->io_error == 0)
462 zio->io_error = zio->io_child_error[c];
463 }
464
465 /*
466 * ==========================================================================
467 * Create the various types of I/O (read, write, free, etc)
468 * ==========================================================================
469 */
470 static zio_t *
471 zio_create(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
472 void *data, uint64_t size, zio_done_func_t *done, void *private,
473 zio_type_t type, int priority, enum zio_flag flags,
474 vdev_t *vd, uint64_t offset, const zbookmark_t *zb,
475 enum zio_stage stage, enum zio_stage pipeline)
476 {
477 zio_t *zio;
478
479 ASSERT3U(size, <=, SPA_MAXBLOCKSIZE);
480 ASSERT(P2PHASE(size, SPA_MINBLOCKSIZE) == 0);
481 ASSERT(P2PHASE(offset, SPA_MINBLOCKSIZE) == 0);
482
483 ASSERT(!vd || spa_config_held(spa, SCL_STATE_ALL, RW_READER));
484 ASSERT(!bp || !(flags & ZIO_FLAG_CONFIG_WRITER));
485 ASSERT(vd || stage == ZIO_STAGE_OPEN);
486
487 zio = kmem_cache_alloc(zio_cache, KM_SLEEP);
488 bzero(zio, sizeof (zio_t));
489
490 mutex_init(&zio->io_lock, NULL, MUTEX_DEFAULT, NULL);
491 cv_init(&zio->io_cv, NULL, CV_DEFAULT, NULL);
492
493 list_create(&zio->io_parent_list, sizeof (zio_link_t),
494 offsetof(zio_link_t, zl_parent_node));
495 list_create(&zio->io_child_list, sizeof (zio_link_t),
496 offsetof(zio_link_t, zl_child_node));
497
498 if (vd != NULL)
499 zio->io_child_type = ZIO_CHILD_VDEV;
500 else if (flags & ZIO_FLAG_GANG_CHILD)
501 zio->io_child_type = ZIO_CHILD_GANG;
502 else if (flags & ZIO_FLAG_DDT_CHILD)
503 zio->io_child_type = ZIO_CHILD_DDT;
504 else
505 zio->io_child_type = ZIO_CHILD_LOGICAL;
506
507 if (bp != NULL) {
508 zio->io_bp = (blkptr_t *)bp;
509 zio->io_bp_copy = *bp;
510 zio->io_bp_orig = *bp;
511 if (type != ZIO_TYPE_WRITE ||
512 zio->io_child_type == ZIO_CHILD_DDT)
513 zio->io_bp = &zio->io_bp_copy; /* so caller can free */
514 if (zio->io_child_type == ZIO_CHILD_LOGICAL)
515 zio->io_logical = zio;
516 if (zio->io_child_type > ZIO_CHILD_GANG && BP_IS_GANG(bp))
517 pipeline |= ZIO_GANG_STAGES;
518 }
519
520 zio->io_spa = spa;
521 zio->io_txg = txg;
522 zio->io_done = done;
523 zio->io_private = private;
524 zio->io_type = type;
525 zio->io_priority = priority;
526 zio->io_vd = vd;
527 zio->io_offset = offset;
528 zio->io_orig_data = zio->io_data = data;
529 zio->io_orig_size = zio->io_size = size;
530 zio->io_orig_flags = zio->io_flags = flags;
531 zio->io_orig_stage = zio->io_stage = stage;
532 zio->io_orig_pipeline = zio->io_pipeline = pipeline;
533
534 zio->io_state[ZIO_WAIT_READY] = (stage >= ZIO_STAGE_READY);
535 zio->io_state[ZIO_WAIT_DONE] = (stage >= ZIO_STAGE_DONE);
536
537 if (zb != NULL)
538 zio->io_bookmark = *zb;
539
540 if (pio != NULL) {
541 if (zio->io_logical == NULL)
542 zio->io_logical = pio->io_logical;
543 if (zio->io_child_type == ZIO_CHILD_GANG)
544 zio->io_gang_leader = pio->io_gang_leader;
545 zio_add_child(pio, zio);
546 }
547
548 return (zio);
549 }
550
551 static void
552 zio_destroy(zio_t *zio)
553 {
554 list_destroy(&zio->io_parent_list);
555 list_destroy(&zio->io_child_list);
556 mutex_destroy(&zio->io_lock);
557 cv_destroy(&zio->io_cv);
558 kmem_cache_free(zio_cache, zio);
559 }
560
561 zio_t *
562 zio_null(zio_t *pio, spa_t *spa, vdev_t *vd, zio_done_func_t *done,
563 void *private, enum zio_flag flags)
564 {
565 zio_t *zio;
566
567 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private,
568 ZIO_TYPE_NULL, ZIO_PRIORITY_NOW, flags, vd, 0, NULL,
569 ZIO_STAGE_OPEN, ZIO_INTERLOCK_PIPELINE);
570
571 return (zio);
572 }
573
574 zio_t *
575 zio_root(spa_t *spa, zio_done_func_t *done, void *private, enum zio_flag flags)
576 {
577 return (zio_null(NULL, spa, NULL, done, private, flags));
578 }
579
580 zio_t *
581 zio_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
582 void *data, uint64_t size, zio_done_func_t *done, void *private,
583 int priority, enum zio_flag flags, const zbookmark_t *zb)
584 {
585 zio_t *zio;
586
587 zio = zio_create(pio, spa, BP_PHYSICAL_BIRTH(bp), bp,
588 data, size, done, private,
589 ZIO_TYPE_READ, priority, flags, NULL, 0, zb,
590 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ?
591 ZIO_DDT_CHILD_READ_PIPELINE : ZIO_READ_PIPELINE);
592
593 return (zio);
594 }
595
596 zio_t *
597 zio_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
598 void *data, uint64_t size, const zio_prop_t *zp,
599 zio_done_func_t *ready, zio_done_func_t *done, void *private,
600 int priority, enum zio_flag flags, const zbookmark_t *zb)
601 {
602 zio_t *zio;
603
604 ASSERT(zp->zp_checksum >= ZIO_CHECKSUM_OFF &&
605 zp->zp_checksum < ZIO_CHECKSUM_FUNCTIONS &&
606 zp->zp_compress >= ZIO_COMPRESS_OFF &&
607 zp->zp_compress < ZIO_COMPRESS_FUNCTIONS &&
608 zp->zp_type < DMU_OT_NUMTYPES &&
609 zp->zp_level < 32 &&
610 zp->zp_copies > 0 &&
611 zp->zp_copies <= spa_max_replication(spa) &&
612 zp->zp_dedup <= 1 &&
613 zp->zp_dedup_verify <= 1);
614
615 zio = zio_create(pio, spa, txg, bp, data, size, done, private,
616 ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb,
617 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ?
618 ZIO_DDT_CHILD_WRITE_PIPELINE : ZIO_WRITE_PIPELINE);
619
620 zio->io_ready = ready;
621 zio->io_prop = *zp;
622
623 return (zio);
624 }
625
626 zio_t *
627 zio_rewrite(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, void *data,
628 uint64_t size, zio_done_func_t *done, void *private, int priority,
629 enum zio_flag flags, zbookmark_t *zb)
630 {
631 zio_t *zio;
632
633 zio = zio_create(pio, spa, txg, bp, data, size, done, private,
634 ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb,
635 ZIO_STAGE_OPEN, ZIO_REWRITE_PIPELINE);
636
637 return (zio);
638 }
639
640 void
641 zio_write_override(zio_t *zio, blkptr_t *bp, int copies)
642 {
643 ASSERT(zio->io_type == ZIO_TYPE_WRITE);
644 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
645 ASSERT(zio->io_stage == ZIO_STAGE_OPEN);
646 ASSERT(zio->io_txg == spa_syncing_txg(zio->io_spa));
647
648 zio->io_prop.zp_copies = copies;
649 zio->io_bp_override = bp;
650 }
651
652 void
653 zio_free(spa_t *spa, uint64_t txg, const blkptr_t *bp)
654 {
655 bplist_append(&spa->spa_free_bplist[txg & TXG_MASK], bp);
656 }
657
658 zio_t *
659 zio_free_sync(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
660 enum zio_flag flags)
661 {
662 zio_t *zio;
663
664 dprintf_bp(bp, "freeing in txg %llu, pass %u",
665 (longlong_t)txg, spa->spa_sync_pass);
666
667 ASSERT(!BP_IS_HOLE(bp));
668 ASSERT(spa_syncing_txg(spa) == txg);
669 ASSERT(spa_sync_pass(spa) <= SYNC_PASS_DEFERRED_FREE);
670
671 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp),
672 NULL, NULL, ZIO_TYPE_FREE, ZIO_PRIORITY_FREE, flags,
673 NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_FREE_PIPELINE);
674
675 return (zio);
676 }
677
678 zio_t *
679 zio_claim(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
680 zio_done_func_t *done, void *private, enum zio_flag flags)
681 {
682 zio_t *zio;
683
684 /*
685 * A claim is an allocation of a specific block. Claims are needed
686 * to support immediate writes in the intent log. The issue is that
687 * immediate writes contain committed data, but in a txg that was
688 * *not* committed. Upon opening the pool after an unclean shutdown,
689 * the intent log claims all blocks that contain immediate write data
690 * so that the SPA knows they're in use.
691 *
692 * All claims *must* be resolved in the first txg -- before the SPA
693 * starts allocating blocks -- so that nothing is allocated twice.
694 * If txg == 0 we just verify that the block is claimable.
695 */
696 ASSERT3U(spa->spa_uberblock.ub_rootbp.blk_birth, <, spa_first_txg(spa));
697 ASSERT(txg == spa_first_txg(spa) || txg == 0);
698 ASSERT(!BP_GET_DEDUP(bp) || !spa_writeable(spa)); /* zdb(1M) */
699
700 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp),
701 done, private, ZIO_TYPE_CLAIM, ZIO_PRIORITY_NOW, flags,
702 NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_CLAIM_PIPELINE);
703
704 return (zio);
705 }
706
707 zio_t *
708 zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd,
709 zio_done_func_t *done, void *private, int priority, enum zio_flag flags)
710 {
711 zio_t *zio;
712 int c;
713
714 if (vd->vdev_children == 0) {
715 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private,
716 ZIO_TYPE_IOCTL, priority, flags, vd, 0, NULL,
717 ZIO_STAGE_OPEN, ZIO_IOCTL_PIPELINE);
718
719 zio->io_cmd = cmd;
720 } else {
721 zio = zio_null(pio, spa, NULL, NULL, NULL, flags);
722
723 for (c = 0; c < vd->vdev_children; c++)
724 zio_nowait(zio_ioctl(zio, spa, vd->vdev_child[c], cmd,
725 done, private, priority, flags));
726 }
727
728 return (zio);
729 }
730
731 zio_t *
732 zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size,
733 void *data, int checksum, zio_done_func_t *done, void *private,
734 int priority, enum zio_flag flags, boolean_t labels)
735 {
736 zio_t *zio;
737
738 ASSERT(vd->vdev_children == 0);
739 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE ||
740 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE);
741 ASSERT3U(offset + size, <=, vd->vdev_psize);
742
743 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private,
744 ZIO_TYPE_READ, priority, flags, vd, offset, NULL,
745 ZIO_STAGE_OPEN, ZIO_READ_PHYS_PIPELINE);
746
747 zio->io_prop.zp_checksum = checksum;
748
749 return (zio);
750 }
751
752 zio_t *
753 zio_write_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size,
754 void *data, int checksum, zio_done_func_t *done, void *private,
755 int priority, enum zio_flag flags, boolean_t labels)
756 {
757 zio_t *zio;
758
759 ASSERT(vd->vdev_children == 0);
760 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE ||
761 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE);
762 ASSERT3U(offset + size, <=, vd->vdev_psize);
763
764 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private,
765 ZIO_TYPE_WRITE, priority, flags, vd, offset, NULL,
766 ZIO_STAGE_OPEN, ZIO_WRITE_PHYS_PIPELINE);
767
768 zio->io_prop.zp_checksum = checksum;
769
770 if (zio_checksum_table[checksum].ci_eck) {
771 /*
772 * zec checksums are necessarily destructive -- they modify
773 * the end of the write buffer to hold the verifier/checksum.
774 * Therefore, we must make a local copy in case the data is
775 * being written to multiple places in parallel.
776 */
777 void *wbuf = zio_buf_alloc(size);
778 bcopy(data, wbuf, size);
779 zio_push_transform(zio, wbuf, size, size, NULL);
780 }
781
782 return (zio);
783 }
784
785 /*
786 * Create a child I/O to do some work for us.
787 */
788 zio_t *
789 zio_vdev_child_io(zio_t *pio, blkptr_t *bp, vdev_t *vd, uint64_t offset,
790 void *data, uint64_t size, int type, int priority, enum zio_flag flags,
791 zio_done_func_t *done, void *private)
792 {
793 enum zio_stage pipeline = ZIO_VDEV_CHILD_PIPELINE;
794 zio_t *zio;
795
796 ASSERT(vd->vdev_parent ==
797 (pio->io_vd ? pio->io_vd : pio->io_spa->spa_root_vdev));
798
799 if (type == ZIO_TYPE_READ && bp != NULL) {
800 /*
801 * If we have the bp, then the child should perform the
802 * checksum and the parent need not. This pushes error
803 * detection as close to the leaves as possible and
804 * eliminates redundant checksums in the interior nodes.
805 */
806 pipeline |= ZIO_STAGE_CHECKSUM_VERIFY;
807 pio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY;
808 }
809
810 if (vd->vdev_children == 0)
811 offset += VDEV_LABEL_START_SIZE;
812
813 flags |= ZIO_VDEV_CHILD_FLAGS(pio) | ZIO_FLAG_DONT_PROPAGATE;
814
815 /*
816 * If we've decided to do a repair, the write is not speculative --
817 * even if the original read was.
818 */
819 if (flags & ZIO_FLAG_IO_REPAIR)
820 flags &= ~ZIO_FLAG_SPECULATIVE;
821
822 zio = zio_create(pio, pio->io_spa, pio->io_txg, bp, data, size,
823 done, private, type, priority, flags, vd, offset, &pio->io_bookmark,
824 ZIO_STAGE_VDEV_IO_START >> 1, pipeline);
825
826 return (zio);
827 }
828
829 zio_t *
830 zio_vdev_delegated_io(vdev_t *vd, uint64_t offset, void *data, uint64_t size,
831 int type, int priority, enum zio_flag flags,
832 zio_done_func_t *done, void *private)
833 {
834 zio_t *zio;
835
836 ASSERT(vd->vdev_ops->vdev_op_leaf);
837
838 zio = zio_create(NULL, vd->vdev_spa, 0, NULL,
839 data, size, done, private, type, priority,
840 flags | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_RETRY,
841 vd, offset, NULL,
842 ZIO_STAGE_VDEV_IO_START >> 1, ZIO_VDEV_CHILD_PIPELINE);
843
844 return (zio);
845 }
846
847 void
848 zio_flush(zio_t *zio, vdev_t *vd)
849 {
850 zio_nowait(zio_ioctl(zio, zio->io_spa, vd, DKIOCFLUSHWRITECACHE,
851 NULL, NULL, ZIO_PRIORITY_NOW,
852 ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY));
853 }
854
855 void
856 zio_shrink(zio_t *zio, uint64_t size)
857 {
858 ASSERT(zio->io_executor == NULL);
859 ASSERT(zio->io_orig_size == zio->io_size);
860 ASSERT(size <= zio->io_size);
861
862 /*
863 * We don't shrink for raidz because of problems with the
864 * reconstruction when reading back less than the block size.
865 * Note, BP_IS_RAIDZ() assumes no compression.
866 */
867 ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF);
868 if (!BP_IS_RAIDZ(zio->io_bp))
869 zio->io_orig_size = zio->io_size = size;
870 }
871
872 /*
873 * ==========================================================================
874 * Prepare to read and write logical blocks
875 * ==========================================================================
876 */
877
878 static int
879 zio_read_bp_init(zio_t *zio)
880 {
881 blkptr_t *bp = zio->io_bp;
882
883 if (BP_GET_COMPRESS(bp) != ZIO_COMPRESS_OFF &&
884 zio->io_child_type == ZIO_CHILD_LOGICAL &&
885 !(zio->io_flags & ZIO_FLAG_RAW)) {
886 uint64_t psize = BP_GET_PSIZE(bp);
887 void *cbuf = zio_buf_alloc(psize);
888
889 zio_push_transform(zio, cbuf, psize, psize, zio_decompress);
890 }
891
892 if (!dmu_ot[BP_GET_TYPE(bp)].ot_metadata && BP_GET_LEVEL(bp) == 0)
893 zio->io_flags |= ZIO_FLAG_DONT_CACHE;
894
895 if (BP_GET_TYPE(bp) == DMU_OT_DDT_ZAP)
896 zio->io_flags |= ZIO_FLAG_DONT_CACHE;
897
898 if (BP_GET_DEDUP(bp) && zio->io_child_type == ZIO_CHILD_LOGICAL)
899 zio->io_pipeline = ZIO_DDT_READ_PIPELINE;
900
901 return (ZIO_PIPELINE_CONTINUE);
902 }
903
904 static int
905 zio_write_bp_init(zio_t *zio)
906 {
907 spa_t *spa = zio->io_spa;
908 zio_prop_t *zp = &zio->io_prop;
909 enum zio_compress compress = zp->zp_compress;
910 blkptr_t *bp = zio->io_bp;
911 uint64_t lsize = zio->io_size;
912 uint64_t psize = lsize;
913 int pass = 1;
914
915 /*
916 * If our children haven't all reached the ready stage,
917 * wait for them and then repeat this pipeline stage.
918 */
919 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) ||
920 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_READY))
921 return (ZIO_PIPELINE_STOP);
922
923 if (!IO_IS_ALLOCATING(zio))
924 return (ZIO_PIPELINE_CONTINUE);
925
926 ASSERT(zio->io_child_type != ZIO_CHILD_DDT);
927
928 if (zio->io_bp_override) {
929 ASSERT(bp->blk_birth != zio->io_txg);
930 ASSERT(BP_GET_DEDUP(zio->io_bp_override) == 0);
931
932 *bp = *zio->io_bp_override;
933 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
934
935 if (BP_IS_HOLE(bp) || !zp->zp_dedup)
936 return (ZIO_PIPELINE_CONTINUE);
937
938 ASSERT(zio_checksum_table[zp->zp_checksum].ci_dedup ||
939 zp->zp_dedup_verify);
940
941 if (BP_GET_CHECKSUM(bp) == zp->zp_checksum) {
942 BP_SET_DEDUP(bp, 1);
943 zio->io_pipeline |= ZIO_STAGE_DDT_WRITE;
944 return (ZIO_PIPELINE_CONTINUE);
945 }
946 zio->io_bp_override = NULL;
947 BP_ZERO(bp);
948 }
949
950 if (bp->blk_birth == zio->io_txg) {
951 /*
952 * We're rewriting an existing block, which means we're
953 * working on behalf of spa_sync(). For spa_sync() to
954 * converge, it must eventually be the case that we don't
955 * have to allocate new blocks. But compression changes
956 * the blocksize, which forces a reallocate, and makes
957 * convergence take longer. Therefore, after the first
958 * few passes, stop compressing to ensure convergence.
959 */
960 pass = spa_sync_pass(spa);
961
962 ASSERT(zio->io_txg == spa_syncing_txg(spa));
963 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
964 ASSERT(!BP_GET_DEDUP(bp));
965
966 if (pass > SYNC_PASS_DONT_COMPRESS)
967 compress = ZIO_COMPRESS_OFF;
968
969 /* Make sure someone doesn't change their mind on overwrites */
970 ASSERT(MIN(zp->zp_copies + BP_IS_GANG(bp),
971 spa_max_replication(spa)) == BP_GET_NDVAS(bp));
972 }
973
974 if (compress != ZIO_COMPRESS_OFF) {
975 void *cbuf = zio_buf_alloc(lsize);
976 psize = zio_compress_data(compress, zio->io_data, cbuf, lsize);
977 if (psize == 0 || psize == lsize) {
978 compress = ZIO_COMPRESS_OFF;
979 zio_buf_free(cbuf, lsize);
980 } else {
981 ASSERT(psize < lsize);
982 zio_push_transform(zio, cbuf, psize, lsize, NULL);
983 }
984 }
985
986 /*
987 * The final pass of spa_sync() must be all rewrites, but the first
988 * few passes offer a trade-off: allocating blocks defers convergence,
989 * but newly allocated blocks are sequential, so they can be written
990 * to disk faster. Therefore, we allow the first few passes of
991 * spa_sync() to allocate new blocks, but force rewrites after that.
992 * There should only be a handful of blocks after pass 1 in any case.
993 */
994 if (bp->blk_birth == zio->io_txg && BP_GET_PSIZE(bp) == psize &&
995 pass > SYNC_PASS_REWRITE) {
996 ASSERT(psize != 0);
997 enum zio_stage gang_stages = zio->io_pipeline & ZIO_GANG_STAGES;
998 zio->io_pipeline = ZIO_REWRITE_PIPELINE | gang_stages;
999 zio->io_flags |= ZIO_FLAG_IO_REWRITE;
1000 } else {
1001 BP_ZERO(bp);
1002 zio->io_pipeline = ZIO_WRITE_PIPELINE;
1003 }
1004
1005 if (psize == 0) {
1006 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1007 } else {
1008 ASSERT(zp->zp_checksum != ZIO_CHECKSUM_GANG_HEADER);
1009 BP_SET_LSIZE(bp, lsize);
1010 BP_SET_PSIZE(bp, psize);
1011 BP_SET_COMPRESS(bp, compress);
1012 BP_SET_CHECKSUM(bp, zp->zp_checksum);
1013 BP_SET_TYPE(bp, zp->zp_type);
1014 BP_SET_LEVEL(bp, zp->zp_level);
1015 BP_SET_DEDUP(bp, zp->zp_dedup);
1016 BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER);
1017 if (zp->zp_dedup) {
1018 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1019 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE));
1020 zio->io_pipeline = ZIO_DDT_WRITE_PIPELINE;
1021 }
1022 }
1023
1024 return (ZIO_PIPELINE_CONTINUE);
1025 }
1026
1027 static int
1028 zio_free_bp_init(zio_t *zio)
1029 {
1030 blkptr_t *bp = zio->io_bp;
1031
1032 if (zio->io_child_type == ZIO_CHILD_LOGICAL) {
1033 if (BP_GET_DEDUP(bp))
1034 zio->io_pipeline = ZIO_DDT_FREE_PIPELINE;
1035 }
1036
1037 return (ZIO_PIPELINE_CONTINUE);
1038 }
1039
1040 /*
1041 * ==========================================================================
1042 * Execute the I/O pipeline
1043 * ==========================================================================
1044 */
1045
1046 static void
1047 zio_taskq_dispatch(zio_t *zio, enum zio_taskq_type q, boolean_t cutinline)
1048 {
1049 spa_t *spa = zio->io_spa;
1050 zio_type_t t = zio->io_type;
1051 int flags = TQ_SLEEP | (cutinline ? TQ_FRONT : 0);
1052
1053 /*
1054 * If we're a config writer or a probe, the normal issue and
1055 * interrupt threads may all be blocked waiting for the config lock.
1056 * In this case, select the otherwise-unused taskq for ZIO_TYPE_NULL.
1057 */
1058 if (zio->io_flags & (ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_PROBE))
1059 t = ZIO_TYPE_NULL;
1060
1061 /*
1062 * A similar issue exists for the L2ARC write thread until L2ARC 2.0.
1063 */
1064 if (t == ZIO_TYPE_WRITE && zio->io_vd && zio->io_vd->vdev_aux)
1065 t = ZIO_TYPE_NULL;
1066
1067 /*
1068 * If this is a high priority I/O, then use the high priority taskq.
1069 */
1070 if (zio->io_priority == ZIO_PRIORITY_NOW &&
1071 spa->spa_zio_taskq[t][q + 1] != NULL)
1072 q++;
1073
1074 ASSERT3U(q, <, ZIO_TASKQ_TYPES);
1075 (void) taskq_dispatch(spa->spa_zio_taskq[t][q],
1076 (task_func_t *)zio_execute, zio, flags);
1077 }
1078
1079 static boolean_t
1080 zio_taskq_member(zio_t *zio, enum zio_taskq_type q)
1081 {
1082 kthread_t *executor = zio->io_executor;
1083 spa_t *spa = zio->io_spa;
1084
1085 for (zio_type_t t = 0; t < ZIO_TYPES; t++)
1086 if (taskq_member(spa->spa_zio_taskq[t][q], executor))
1087 return (B_TRUE);
1088
1089 return (B_FALSE);
1090 }
1091
1092 static int
1093 zio_issue_async(zio_t *zio)
1094 {
1095 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE);
1096
1097 return (ZIO_PIPELINE_STOP);
1098 }
1099
1100 void
1101 zio_interrupt(zio_t *zio)
1102 {
1103 zio_taskq_dispatch(zio, ZIO_TASKQ_INTERRUPT, B_FALSE);
1104 }
1105
1106 /*
1107 * Execute the I/O pipeline until one of the following occurs:
1108 * (1) the I/O completes; (2) the pipeline stalls waiting for
1109 * dependent child I/Os; (3) the I/O issues, so we're waiting
1110 * for an I/O completion interrupt; (4) the I/O is delegated by
1111 * vdev-level caching or aggregation; (5) the I/O is deferred
1112 * due to vdev-level queueing; (6) the I/O is handed off to
1113 * another thread. In all cases, the pipeline stops whenever
1114 * there's no CPU work; it never burns a thread in cv_wait().
1115 *
1116 * There's no locking on io_stage because there's no legitimate way
1117 * for multiple threads to be attempting to process the same I/O.
1118 */
1119 static zio_pipe_stage_t *zio_pipeline[];
1120
1121 void
1122 zio_execute(zio_t *zio)
1123 {
1124 zio->io_executor = curthread;
1125
1126 while (zio->io_stage < ZIO_STAGE_DONE) {
1127 enum zio_stage pipeline = zio->io_pipeline;
1128 enum zio_stage stage = zio->io_stage;
1129 int rv;
1130
1131 ASSERT(!MUTEX_HELD(&zio->io_lock));
1132 ASSERT(ISP2(stage));
1133 ASSERT(zio->io_stall == NULL);
1134
1135 do {
1136 stage <<= 1;
1137 } while ((stage & pipeline) == 0);
1138
1139 ASSERT(stage <= ZIO_STAGE_DONE);
1140
1141 /*
1142 * If we are in interrupt context and this pipeline stage
1143 * will grab a config lock that is held across I/O,
1144 * or may wait for an I/O that needs an interrupt thread
1145 * to complete, issue async to avoid deadlock.
1146 *
1147 * For VDEV_IO_START, we cut in line so that the io will
1148 * be sent to disk promptly.
1149 */
1150 if ((stage & ZIO_BLOCKING_STAGES) && zio->io_vd == NULL &&
1151 zio_taskq_member(zio, ZIO_TASKQ_INTERRUPT)) {
1152 boolean_t cut = (stage == ZIO_STAGE_VDEV_IO_START) ?
1153 zio_requeue_io_start_cut_in_line : B_FALSE;
1154 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, cut);
1155 return;
1156 }
1157
1158 zio->io_stage = stage;
1159 rv = zio_pipeline[highbit(stage) - 1](zio);
1160
1161 if (rv == ZIO_PIPELINE_STOP)
1162 return;
1163
1164 ASSERT(rv == ZIO_PIPELINE_CONTINUE);
1165 }
1166 }
1167
1168 /*
1169 * ==========================================================================
1170 * Initiate I/O, either sync or async
1171 * ==========================================================================
1172 */
1173 int
1174 zio_wait(zio_t *zio)
1175 {
1176 int error;
1177
1178 ASSERT(zio->io_stage == ZIO_STAGE_OPEN);
1179 ASSERT(zio->io_executor == NULL);
1180
1181 zio->io_waiter = curthread;
1182
1183 zio_execute(zio);
1184
1185 mutex_enter(&zio->io_lock);
1186 while (zio->io_executor != NULL)
1187 cv_wait(&zio->io_cv, &zio->io_lock);
1188 mutex_exit(&zio->io_lock);
1189
1190 error = zio->io_error;
1191 zio_destroy(zio);
1192
1193 return (error);
1194 }
1195
1196 void
1197 zio_nowait(zio_t *zio)
1198 {
1199 ASSERT(zio->io_executor == NULL);
1200
1201 if (zio->io_child_type == ZIO_CHILD_LOGICAL &&
1202 zio_unique_parent(zio) == NULL) {
1203 /*
1204 * This is a logical async I/O with no parent to wait for it.
1205 * We add it to the spa_async_root_zio "Godfather" I/O which
1206 * will ensure they complete prior to unloading the pool.
1207 */
1208 spa_t *spa = zio->io_spa;
1209
1210 zio_add_child(spa->spa_async_zio_root, zio);
1211 }
1212
1213 zio_execute(zio);
1214 }
1215
1216 /*
1217 * ==========================================================================
1218 * Reexecute or suspend/resume failed I/O
1219 * ==========================================================================
1220 */
1221
1222 static void
1223 zio_reexecute(zio_t *pio)
1224 {
1225 zio_t *cio, *cio_next;
1226
1227 ASSERT(pio->io_child_type == ZIO_CHILD_LOGICAL);
1228 ASSERT(pio->io_orig_stage == ZIO_STAGE_OPEN);
1229 ASSERT(pio->io_gang_leader == NULL);
1230 ASSERT(pio->io_gang_tree == NULL);
1231
1232 pio->io_flags = pio->io_orig_flags;
1233 pio->io_stage = pio->io_orig_stage;
1234 pio->io_pipeline = pio->io_orig_pipeline;
1235 pio->io_reexecute = 0;
1236 pio->io_error = 0;
1237 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
1238 pio->io_state[w] = 0;
1239 for (int c = 0; c < ZIO_CHILD_TYPES; c++)
1240 pio->io_child_error[c] = 0;
1241
1242 if (IO_IS_ALLOCATING(pio))
1243 BP_ZERO(pio->io_bp);
1244
1245 /*
1246 * As we reexecute pio's children, new children could be created.
1247 * New children go to the head of pio's io_child_list, however,
1248 * so we will (correctly) not reexecute them. The key is that
1249 * the remainder of pio's io_child_list, from 'cio_next' onward,
1250 * cannot be affected by any side effects of reexecuting 'cio'.
1251 */
1252 for (cio = zio_walk_children(pio); cio != NULL; cio = cio_next) {
1253 cio_next = zio_walk_children(pio);
1254 mutex_enter(&pio->io_lock);
1255 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
1256 pio->io_children[cio->io_child_type][w]++;
1257 mutex_exit(&pio->io_lock);
1258 zio_reexecute(cio);
1259 }
1260
1261 /*
1262 * Now that all children have been reexecuted, execute the parent.
1263 * We don't reexecute "The Godfather" I/O here as it's the
1264 * responsibility of the caller to wait on him.
1265 */
1266 if (!(pio->io_flags & ZIO_FLAG_GODFATHER))
1267 zio_execute(pio);
1268 }
1269
1270 void
1271 zio_suspend(spa_t *spa, zio_t *zio)
1272 {
1273 if (spa_get_failmode(spa) == ZIO_FAILURE_MODE_PANIC)
1274 fm_panic("Pool '%s' has encountered an uncorrectable I/O "
1275 "failure and the failure mode property for this pool "
1276 "is set to panic.", spa_name(spa));
1277
1278 zfs_ereport_post(FM_EREPORT_ZFS_IO_FAILURE, spa, NULL, NULL, 0, 0);
1279
1280 mutex_enter(&spa->spa_suspend_lock);
1281
1282 if (spa->spa_suspend_zio_root == NULL)
1283 spa->spa_suspend_zio_root = zio_root(spa, NULL, NULL,
1284 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE |
1285 ZIO_FLAG_GODFATHER);
1286
1287 spa->spa_suspended = B_TRUE;
1288
1289 if (zio != NULL) {
1290 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER));
1291 ASSERT(zio != spa->spa_suspend_zio_root);
1292 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1293 ASSERT(zio_unique_parent(zio) == NULL);
1294 ASSERT(zio->io_stage == ZIO_STAGE_DONE);
1295 zio_add_child(spa->spa_suspend_zio_root, zio);
1296 }
1297
1298 mutex_exit(&spa->spa_suspend_lock);
1299 }
1300
1301 int
1302 zio_resume(spa_t *spa)
1303 {
1304 zio_t *pio;
1305
1306 /*
1307 * Reexecute all previously suspended i/o.
1308 */
1309 mutex_enter(&spa->spa_suspend_lock);
1310 spa->spa_suspended = B_FALSE;
1311 cv_broadcast(&spa->spa_suspend_cv);
1312 pio = spa->spa_suspend_zio_root;
1313 spa->spa_suspend_zio_root = NULL;
1314 mutex_exit(&spa->spa_suspend_lock);
1315
1316 if (pio == NULL)
1317 return (0);
1318
1319 zio_reexecute(pio);
1320 return (zio_wait(pio));
1321 }
1322
1323 void
1324 zio_resume_wait(spa_t *spa)
1325 {
1326 mutex_enter(&spa->spa_suspend_lock);
1327 while (spa_suspended(spa))
1328 cv_wait(&spa->spa_suspend_cv, &spa->spa_suspend_lock);
1329 mutex_exit(&spa->spa_suspend_lock);
1330 }
1331
1332 /*
1333 * ==========================================================================
1334 * Gang blocks.
1335 *
1336 * A gang block is a collection of small blocks that looks to the DMU
1337 * like one large block. When zio_dva_allocate() cannot find a block
1338 * of the requested size, due to either severe fragmentation or the pool
1339 * being nearly full, it calls zio_write_gang_block() to construct the
1340 * block from smaller fragments.
1341 *
1342 * A gang block consists of a gang header (zio_gbh_phys_t) and up to
1343 * three (SPA_GBH_NBLKPTRS) gang members. The gang header is just like
1344 * an indirect block: it's an array of block pointers. It consumes
1345 * only one sector and hence is allocatable regardless of fragmentation.
1346 * The gang header's bps point to its gang members, which hold the data.
1347 *
1348 * Gang blocks are self-checksumming, using the bp's <vdev, offset, txg>
1349 * as the verifier to ensure uniqueness of the SHA256 checksum.
1350 * Critically, the gang block bp's blk_cksum is the checksum of the data,
1351 * not the gang header. This ensures that data block signatures (needed for
1352 * deduplication) are independent of how the block is physically stored.
1353 *
1354 * Gang blocks can be nested: a gang member may itself be a gang block.
1355 * Thus every gang block is a tree in which root and all interior nodes are
1356 * gang headers, and the leaves are normal blocks that contain user data.
1357 * The root of the gang tree is called the gang leader.
1358 *
1359 * To perform any operation (read, rewrite, free, claim) on a gang block,
1360 * zio_gang_assemble() first assembles the gang tree (minus data leaves)
1361 * in the io_gang_tree field of the original logical i/o by recursively
1362 * reading the gang leader and all gang headers below it. This yields
1363 * an in-core tree containing the contents of every gang header and the
1364 * bps for every constituent of the gang block.
1365 *
1366 * With the gang tree now assembled, zio_gang_issue() just walks the gang tree
1367 * and invokes a callback on each bp. To free a gang block, zio_gang_issue()
1368 * calls zio_free_gang() -- a trivial wrapper around zio_free() -- for each bp.
1369 * zio_claim_gang() provides a similarly trivial wrapper for zio_claim().
1370 * zio_read_gang() is a wrapper around zio_read() that omits reading gang
1371 * headers, since we already have those in io_gang_tree. zio_rewrite_gang()
1372 * performs a zio_rewrite() of the data or, for gang headers, a zio_rewrite()
1373 * of the gang header plus zio_checksum_compute() of the data to update the
1374 * gang header's blk_cksum as described above.
1375 *
1376 * The two-phase assemble/issue model solves the problem of partial failure --
1377 * what if you'd freed part of a gang block but then couldn't read the
1378 * gang header for another part? Assembling the entire gang tree first
1379 * ensures that all the necessary gang header I/O has succeeded before
1380 * starting the actual work of free, claim, or write. Once the gang tree
1381 * is assembled, free and claim are in-memory operations that cannot fail.
1382 *
1383 * In the event that a gang write fails, zio_dva_unallocate() walks the
1384 * gang tree to immediately free (i.e. insert back into the space map)
1385 * everything we've allocated. This ensures that we don't get ENOSPC
1386 * errors during repeated suspend/resume cycles due to a flaky device.
1387 *
1388 * Gang rewrites only happen during sync-to-convergence. If we can't assemble
1389 * the gang tree, we won't modify the block, so we can safely defer the free
1390 * (knowing that the block is still intact). If we *can* assemble the gang
1391 * tree, then even if some of the rewrites fail, zio_dva_unallocate() will free
1392 * each constituent bp and we can allocate a new block on the next sync pass.
1393 *
1394 * In all cases, the gang tree allows complete recovery from partial failure.
1395 * ==========================================================================
1396 */
1397
1398 static zio_t *
1399 zio_read_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1400 {
1401 if (gn != NULL)
1402 return (pio);
1403
1404 return (zio_read(pio, pio->io_spa, bp, data, BP_GET_PSIZE(bp),
1405 NULL, NULL, pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio),
1406 &pio->io_bookmark));
1407 }
1408
1409 zio_t *
1410 zio_rewrite_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1411 {
1412 zio_t *zio;
1413
1414 if (gn != NULL) {
1415 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp,
1416 gn->gn_gbh, SPA_GANGBLOCKSIZE, NULL, NULL, pio->io_priority,
1417 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
1418 /*
1419 * As we rewrite each gang header, the pipeline will compute
1420 * a new gang block header checksum for it; but no one will
1421 * compute a new data checksum, so we do that here. The one
1422 * exception is the gang leader: the pipeline already computed
1423 * its data checksum because that stage precedes gang assembly.
1424 * (Presently, nothing actually uses interior data checksums;
1425 * this is just good hygiene.)
1426 */
1427 if (gn != pio->io_gang_leader->io_gang_tree) {
1428 zio_checksum_compute(zio, BP_GET_CHECKSUM(bp),
1429 data, BP_GET_PSIZE(bp));
1430 }
1431 /*
1432 * If we are here to damage data for testing purposes,
1433 * leave the GBH alone so that we can detect the damage.
1434 */
1435 if (pio->io_gang_leader->io_flags & ZIO_FLAG_INDUCE_DAMAGE)
1436 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES;
1437 } else {
1438 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp,
1439 data, BP_GET_PSIZE(bp), NULL, NULL, pio->io_priority,
1440 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
1441 }
1442
1443 return (zio);
1444 }
1445
1446 /* ARGSUSED */
1447 zio_t *
1448 zio_free_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1449 {
1450 return (zio_free_sync(pio, pio->io_spa, pio->io_txg, bp,
1451 ZIO_GANG_CHILD_FLAGS(pio)));
1452 }
1453
1454 /* ARGSUSED */
1455 zio_t *
1456 zio_claim_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1457 {
1458 return (zio_claim(pio, pio->io_spa, pio->io_txg, bp,
1459 NULL, NULL, ZIO_GANG_CHILD_FLAGS(pio)));
1460 }
1461
1462 static zio_gang_issue_func_t *zio_gang_issue_func[ZIO_TYPES] = {
1463 NULL,
1464 zio_read_gang,
1465 zio_rewrite_gang,
1466 zio_free_gang,
1467 zio_claim_gang,
1468 NULL
1469 };
1470
1471 static void zio_gang_tree_assemble_done(zio_t *zio);
1472
1473 static zio_gang_node_t *
1474 zio_gang_node_alloc(zio_gang_node_t **gnpp)
1475 {
1476 zio_gang_node_t *gn;
1477
1478 ASSERT(*gnpp == NULL);
1479
1480 gn = kmem_zalloc(sizeof (*gn), KM_SLEEP);
1481 gn->gn_gbh = zio_buf_alloc(SPA_GANGBLOCKSIZE);
1482 *gnpp = gn;
1483
1484 return (gn);
1485 }
1486
1487 static void
1488 zio_gang_node_free(zio_gang_node_t **gnpp)
1489 {
1490 zio_gang_node_t *gn = *gnpp;
1491
1492 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++)
1493 ASSERT(gn->gn_child[g] == NULL);
1494
1495 zio_buf_free(gn->gn_gbh, SPA_GANGBLOCKSIZE);
1496 kmem_free(gn, sizeof (*gn));
1497 *gnpp = NULL;
1498 }
1499
1500 static void
1501 zio_gang_tree_free(zio_gang_node_t **gnpp)
1502 {
1503 zio_gang_node_t *gn = *gnpp;
1504
1505 if (gn == NULL)
1506 return;
1507
1508 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++)
1509 zio_gang_tree_free(&gn->gn_child[g]);
1510
1511 zio_gang_node_free(gnpp);
1512 }
1513
1514 static void
1515 zio_gang_tree_assemble(zio_t *gio, blkptr_t *bp, zio_gang_node_t **gnpp)
1516 {
1517 zio_gang_node_t *gn = zio_gang_node_alloc(gnpp);
1518
1519 ASSERT(gio->io_gang_leader == gio);
1520 ASSERT(BP_IS_GANG(bp));
1521
1522 zio_nowait(zio_read(gio, gio->io_spa, bp, gn->gn_gbh,
1523 SPA_GANGBLOCKSIZE, zio_gang_tree_assemble_done, gn,
1524 gio->io_priority, ZIO_GANG_CHILD_FLAGS(gio), &gio->io_bookmark));
1525 }
1526
1527 static void
1528 zio_gang_tree_assemble_done(zio_t *zio)
1529 {
1530 zio_t *gio = zio->io_gang_leader;
1531 zio_gang_node_t *gn = zio->io_private;
1532 blkptr_t *bp = zio->io_bp;
1533
1534 ASSERT(gio == zio_unique_parent(zio));
1535 ASSERT(zio->io_child_count == 0);
1536
1537 if (zio->io_error)
1538 return;
1539
1540 if (BP_SHOULD_BYTESWAP(bp))
1541 byteswap_uint64_array(zio->io_data, zio->io_size);
1542
1543 ASSERT(zio->io_data == gn->gn_gbh);
1544 ASSERT(zio->io_size == SPA_GANGBLOCKSIZE);
1545 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC);
1546
1547 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
1548 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g];
1549 if (!BP_IS_GANG(gbp))
1550 continue;
1551 zio_gang_tree_assemble(gio, gbp, &gn->gn_child[g]);
1552 }
1553 }
1554
1555 static void
1556 zio_gang_tree_issue(zio_t *pio, zio_gang_node_t *gn, blkptr_t *bp, void *data)
1557 {
1558 zio_t *gio = pio->io_gang_leader;
1559 zio_t *zio;
1560
1561 ASSERT(BP_IS_GANG(bp) == !!gn);
1562 ASSERT(BP_GET_CHECKSUM(bp) == BP_GET_CHECKSUM(gio->io_bp));
1563 ASSERT(BP_GET_LSIZE(bp) == BP_GET_PSIZE(bp) || gn == gio->io_gang_tree);
1564
1565 /*
1566 * If you're a gang header, your data is in gn->gn_gbh.
1567 * If you're a gang member, your data is in 'data' and gn == NULL.
1568 */
1569 zio = zio_gang_issue_func[gio->io_type](pio, bp, gn, data);
1570
1571 if (gn != NULL) {
1572 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC);
1573
1574 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
1575 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g];
1576 if (BP_IS_HOLE(gbp))
1577 continue;
1578 zio_gang_tree_issue(zio, gn->gn_child[g], gbp, data);
1579 data = (char *)data + BP_GET_PSIZE(gbp);
1580 }
1581 }
1582
1583 if (gn == gio->io_gang_tree)
1584 ASSERT3P((char *)gio->io_data + gio->io_size, ==, data);
1585
1586 if (zio != pio)
1587 zio_nowait(zio);
1588 }
1589
1590 static int
1591 zio_gang_assemble(zio_t *zio)
1592 {
1593 blkptr_t *bp = zio->io_bp;
1594
1595 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == NULL);
1596 ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
1597
1598 zio->io_gang_leader = zio;
1599
1600 zio_gang_tree_assemble(zio, bp, &zio->io_gang_tree);
1601
1602 return (ZIO_PIPELINE_CONTINUE);
1603 }
1604
1605 static int
1606 zio_gang_issue(zio_t *zio)
1607 {
1608 blkptr_t *bp = zio->io_bp;
1609
1610 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE))
1611 return (ZIO_PIPELINE_STOP);
1612
1613 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == zio);
1614 ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
1615
1616 if (zio->io_child_error[ZIO_CHILD_GANG] == 0)
1617 zio_gang_tree_issue(zio, zio->io_gang_tree, bp, zio->io_data);
1618 else
1619 zio_gang_tree_free(&zio->io_gang_tree);
1620
1621 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1622
1623 return (ZIO_PIPELINE_CONTINUE);
1624 }
1625
1626 static void
1627 zio_write_gang_member_ready(zio_t *zio)
1628 {
1629 zio_t *pio = zio_unique_parent(zio);
1630 zio_t *gio = zio->io_gang_leader;
1631 dva_t *cdva = zio->io_bp->blk_dva;
1632 dva_t *pdva = pio->io_bp->blk_dva;
1633 uint64_t asize;
1634
1635 if (BP_IS_HOLE(zio->io_bp))
1636 return;
1637
1638 ASSERT(BP_IS_HOLE(&zio->io_bp_orig));
1639
1640 ASSERT(zio->io_child_type == ZIO_CHILD_GANG);
1641 ASSERT3U(zio->io_prop.zp_copies, ==, gio->io_prop.zp_copies);
1642 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(zio->io_bp));
1643 ASSERT3U(pio->io_prop.zp_copies, <=, BP_GET_NDVAS(pio->io_bp));
1644 ASSERT3U(BP_GET_NDVAS(zio->io_bp), <=, BP_GET_NDVAS(pio->io_bp));
1645
1646 mutex_enter(&pio->io_lock);
1647 for (int d = 0; d < BP_GET_NDVAS(zio->io_bp); d++) {
1648 ASSERT(DVA_GET_GANG(&pdva[d]));
1649 asize = DVA_GET_ASIZE(&pdva[d]);
1650 asize += DVA_GET_ASIZE(&cdva[d]);
1651 DVA_SET_ASIZE(&pdva[d], asize);
1652 }
1653 mutex_exit(&pio->io_lock);
1654 }
1655
1656 static int
1657 zio_write_gang_block(zio_t *pio)
1658 {
1659 spa_t *spa = pio->io_spa;
1660 blkptr_t *bp = pio->io_bp;
1661 zio_t *gio = pio->io_gang_leader;
1662 zio_t *zio;
1663 zio_gang_node_t *gn, **gnpp;
1664 zio_gbh_phys_t *gbh;
1665 uint64_t txg = pio->io_txg;
1666 uint64_t resid = pio->io_size;
1667 uint64_t lsize;
1668 int copies = gio->io_prop.zp_copies;
1669 int gbh_copies = MIN(copies + 1, spa_max_replication(spa));
1670 zio_prop_t zp;
1671 int error;
1672
1673 error = metaslab_alloc(spa, spa_normal_class(spa), SPA_GANGBLOCKSIZE,
1674 bp, gbh_copies, txg, pio == gio ? NULL : gio->io_bp,
1675 METASLAB_HINTBP_FAVOR | METASLAB_GANG_HEADER);
1676 if (error) {
1677 pio->io_error = error;
1678 return (ZIO_PIPELINE_CONTINUE);
1679 }
1680
1681 if (pio == gio) {
1682 gnpp = &gio->io_gang_tree;
1683 } else {
1684 gnpp = pio->io_private;
1685 ASSERT(pio->io_ready == zio_write_gang_member_ready);
1686 }
1687
1688 gn = zio_gang_node_alloc(gnpp);
1689 gbh = gn->gn_gbh;
1690 bzero(gbh, SPA_GANGBLOCKSIZE);
1691
1692 /*
1693 * Create the gang header.
1694 */
1695 zio = zio_rewrite(pio, spa, txg, bp, gbh, SPA_GANGBLOCKSIZE, NULL, NULL,
1696 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
1697
1698 /*
1699 * Create and nowait the gang children.
1700 */
1701 for (int g = 0; resid != 0; resid -= lsize, g++) {
1702 lsize = P2ROUNDUP(resid / (SPA_GBH_NBLKPTRS - g),
1703 SPA_MINBLOCKSIZE);
1704 ASSERT(lsize >= SPA_MINBLOCKSIZE && lsize <= resid);
1705
1706 zp.zp_checksum = gio->io_prop.zp_checksum;
1707 zp.zp_compress = ZIO_COMPRESS_OFF;
1708 zp.zp_type = DMU_OT_NONE;
1709 zp.zp_level = 0;
1710 zp.zp_copies = gio->io_prop.zp_copies;
1711 zp.zp_dedup = 0;
1712 zp.zp_dedup_verify = 0;
1713
1714 zio_nowait(zio_write(zio, spa, txg, &gbh->zg_blkptr[g],
1715 (char *)pio->io_data + (pio->io_size - resid), lsize, &zp,
1716 zio_write_gang_member_ready, NULL, &gn->gn_child[g],
1717 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio),
1718 &pio->io_bookmark));
1719 }
1720
1721 /*
1722 * Set pio's pipeline to just wait for zio to finish.
1723 */
1724 pio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1725
1726 zio_nowait(zio);
1727
1728 return (ZIO_PIPELINE_CONTINUE);
1729 }
1730
1731 /*
1732 * ==========================================================================
1733 * Dedup
1734 * ==========================================================================
1735 */
1736 static void
1737 zio_ddt_child_read_done(zio_t *zio)
1738 {
1739 blkptr_t *bp = zio->io_bp;
1740 ddt_entry_t *dde = zio->io_private;
1741 ddt_phys_t *ddp;
1742 zio_t *pio = zio_unique_parent(zio);
1743
1744 mutex_enter(&pio->io_lock);
1745 ddp = ddt_phys_select(dde, bp);
1746 if (zio->io_error == 0)
1747 ddt_phys_clear(ddp); /* this ddp doesn't need repair */
1748 if (zio->io_error == 0 && dde->dde_repair_data == NULL)
1749 dde->dde_repair_data = zio->io_data;
1750 else
1751 zio_buf_free(zio->io_data, zio->io_size);
1752 mutex_exit(&pio->io_lock);
1753 }
1754
1755 static int
1756 zio_ddt_read_start(zio_t *zio)
1757 {
1758 blkptr_t *bp = zio->io_bp;
1759
1760 ASSERT(BP_GET_DEDUP(bp));
1761 ASSERT(BP_GET_PSIZE(bp) == zio->io_size);
1762 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1763
1764 if (zio->io_child_error[ZIO_CHILD_DDT]) {
1765 ddt_t *ddt = ddt_select(zio->io_spa, bp);
1766 ddt_entry_t *dde = ddt_repair_start(ddt, bp);
1767 ddt_phys_t *ddp = dde->dde_phys;
1768 ddt_phys_t *ddp_self = ddt_phys_select(dde, bp);
1769 blkptr_t blk;
1770
1771 ASSERT(zio->io_vsd == NULL);
1772 zio->io_vsd = dde;
1773
1774 if (ddp_self == NULL)
1775 return (ZIO_PIPELINE_CONTINUE);
1776
1777 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
1778 if (ddp->ddp_phys_birth == 0 || ddp == ddp_self)
1779 continue;
1780 ddt_bp_create(ddt->ddt_checksum, &dde->dde_key, ddp,
1781 &blk);
1782 zio_nowait(zio_read(zio, zio->io_spa, &blk,
1783 zio_buf_alloc(zio->io_size), zio->io_size,
1784 zio_ddt_child_read_done, dde, zio->io_priority,
1785 ZIO_DDT_CHILD_FLAGS(zio) | ZIO_FLAG_DONT_PROPAGATE,
1786 &zio->io_bookmark));
1787 }
1788 return (ZIO_PIPELINE_CONTINUE);
1789 }
1790
1791 zio_nowait(zio_read(zio, zio->io_spa, bp,
1792 zio->io_data, zio->io_size, NULL, NULL, zio->io_priority,
1793 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark));
1794
1795 return (ZIO_PIPELINE_CONTINUE);
1796 }
1797
1798 static int
1799 zio_ddt_read_done(zio_t *zio)
1800 {
1801 blkptr_t *bp = zio->io_bp;
1802
1803 if (zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE))
1804 return (ZIO_PIPELINE_STOP);
1805
1806 ASSERT(BP_GET_DEDUP(bp));
1807 ASSERT(BP_GET_PSIZE(bp) == zio->io_size);
1808 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1809
1810 if (zio->io_child_error[ZIO_CHILD_DDT]) {
1811 ddt_t *ddt = ddt_select(zio->io_spa, bp);
1812 ddt_entry_t *dde = zio->io_vsd;
1813 if (ddt == NULL) {
1814 ASSERT(spa_load_state(zio->io_spa) != SPA_LOAD_NONE);
1815 return (ZIO_PIPELINE_CONTINUE);
1816 }
1817 if (dde == NULL) {
1818 zio->io_stage = ZIO_STAGE_DDT_READ_START >> 1;
1819 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE);
1820 return (ZIO_PIPELINE_STOP);
1821 }
1822 if (dde->dde_repair_data != NULL) {
1823 bcopy(dde->dde_repair_data, zio->io_data, zio->io_size);
1824 zio->io_child_error[ZIO_CHILD_DDT] = 0;
1825 }
1826 ddt_repair_done(ddt, dde);
1827 zio->io_vsd = NULL;
1828 }
1829
1830 ASSERT(zio->io_vsd == NULL);
1831
1832 return (ZIO_PIPELINE_CONTINUE);
1833 }
1834
1835 static boolean_t
1836 zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde)
1837 {
1838 spa_t *spa = zio->io_spa;
1839
1840 /*
1841 * Note: we compare the original data, not the transformed data,
1842 * because when zio->io_bp is an override bp, we will not have
1843 * pushed the I/O transforms. That's an important optimization
1844 * because otherwise we'd compress/encrypt all dmu_sync() data twice.
1845 */
1846 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
1847 zio_t *lio = dde->dde_lead_zio[p];
1848
1849 if (lio != NULL) {
1850 return (lio->io_orig_size != zio->io_orig_size ||
1851 bcmp(zio->io_orig_data, lio->io_orig_data,
1852 zio->io_orig_size) != 0);
1853 }
1854 }
1855
1856 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
1857 ddt_phys_t *ddp = &dde->dde_phys[p];
1858
1859 if (ddp->ddp_phys_birth != 0) {
1860 arc_buf_t *abuf = NULL;
1861 uint32_t aflags = ARC_WAIT;
1862 blkptr_t blk = *zio->io_bp;
1863 int error;
1864
1865 ddt_bp_fill(ddp, &blk, ddp->ddp_phys_birth);
1866
1867 ddt_exit(ddt);
1868
1869 error = arc_read_nolock(NULL, spa, &blk,
1870 arc_getbuf_func, &abuf, ZIO_PRIORITY_SYNC_READ,
1871 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
1872 &aflags, &zio->io_bookmark);
1873
1874 if (error == 0) {
1875 if (arc_buf_size(abuf) != zio->io_orig_size ||
1876 bcmp(abuf->b_data, zio->io_orig_data,
1877 zio->io_orig_size) != 0)
1878 error = EEXIST;
1879 VERIFY(arc_buf_remove_ref(abuf, &abuf) == 1);
1880 }
1881
1882 ddt_enter(ddt);
1883 return (error != 0);
1884 }
1885 }
1886
1887 return (B_FALSE);
1888 }
1889
1890 static void
1891 zio_ddt_child_write_ready(zio_t *zio)
1892 {
1893 int p = zio->io_prop.zp_copies;
1894 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp);
1895 ddt_entry_t *dde = zio->io_private;
1896 ddt_phys_t *ddp = &dde->dde_phys[p];
1897 zio_t *pio;
1898
1899 if (zio->io_error)
1900 return;
1901
1902 ddt_enter(ddt);
1903
1904 ASSERT(dde->dde_lead_zio[p] == zio);
1905
1906 ddt_phys_fill(ddp, zio->io_bp);
1907
1908 while ((pio = zio_walk_parents(zio)) != NULL)
1909 ddt_bp_fill(ddp, pio->io_bp, zio->io_txg);
1910
1911 ddt_exit(ddt);
1912 }
1913
1914 static void
1915 zio_ddt_child_write_done(zio_t *zio)
1916 {
1917 int p = zio->io_prop.zp_copies;
1918 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp);
1919 ddt_entry_t *dde = zio->io_private;
1920 ddt_phys_t *ddp = &dde->dde_phys[p];
1921
1922 ddt_enter(ddt);
1923
1924 ASSERT(ddp->ddp_refcnt == 0);
1925 ASSERT(dde->dde_lead_zio[p] == zio);
1926 dde->dde_lead_zio[p] = NULL;
1927
1928 if (zio->io_error == 0) {
1929 while (zio_walk_parents(zio) != NULL)
1930 ddt_phys_addref(ddp);
1931 } else {
1932 ddt_phys_clear(ddp);
1933 }
1934
1935 ddt_exit(ddt);
1936 }
1937
1938 static void
1939 zio_ddt_ditto_write_done(zio_t *zio)
1940 {
1941 int p = DDT_PHYS_DITTO;
1942 zio_prop_t *zp = &zio->io_prop;
1943 blkptr_t *bp = zio->io_bp;
1944 ddt_t *ddt = ddt_select(zio->io_spa, bp);
1945 ddt_entry_t *dde = zio->io_private;
1946 ddt_phys_t *ddp = &dde->dde_phys[p];
1947 ddt_key_t *ddk = &dde->dde_key;
1948
1949 ddt_enter(ddt);
1950
1951 ASSERT(ddp->ddp_refcnt == 0);
1952 ASSERT(dde->dde_lead_zio[p] == zio);
1953 dde->dde_lead_zio[p] = NULL;
1954
1955 if (zio->io_error == 0) {
1956 ASSERT(ZIO_CHECKSUM_EQUAL(bp->blk_cksum, ddk->ddk_cksum));
1957 ASSERT(zp->zp_copies < SPA_DVAS_PER_BP);
1958 ASSERT(zp->zp_copies == BP_GET_NDVAS(bp) - BP_IS_GANG(bp));
1959 if (ddp->ddp_phys_birth != 0)
1960 ddt_phys_free(ddt, ddk, ddp, zio->io_txg);
1961 ddt_phys_fill(ddp, bp);
1962 }
1963
1964 ddt_exit(ddt);
1965 }
1966
1967 static int
1968 zio_ddt_write(zio_t *zio)
1969 {
1970 spa_t *spa = zio->io_spa;
1971 blkptr_t *bp = zio->io_bp;
1972 uint64_t txg = zio->io_txg;
1973 zio_prop_t *zp = &zio->io_prop;
1974 int p = zp->zp_copies;
1975 int ditto_copies;
1976 zio_t *cio = NULL;
1977 zio_t *dio = NULL;
1978 ddt_t *ddt = ddt_select(spa, bp);
1979 ddt_entry_t *dde;
1980 ddt_phys_t *ddp;
1981
1982 ASSERT(BP_GET_DEDUP(bp));
1983 ASSERT(BP_GET_CHECKSUM(bp) == zp->zp_checksum);
1984 ASSERT(BP_IS_HOLE(bp) || zio->io_bp_override);
1985
1986 ddt_enter(ddt);
1987 dde = ddt_lookup(ddt, bp, B_TRUE);
1988 ddp = &dde->dde_phys[p];
1989
1990 if (zp->zp_dedup_verify && zio_ddt_collision(zio, ddt, dde)) {
1991 /*
1992 * If we're using a weak checksum, upgrade to a strong checksum
1993 * and try again. If we're already using a strong checksum,
1994 * we can't resolve it, so just convert to an ordinary write.
1995 * (And automatically e-mail a paper to Nature?)
1996 */
1997 if (!zio_checksum_table[zp->zp_checksum].ci_dedup) {
1998 zp->zp_checksum = spa_dedup_checksum(spa);
1999 zio_pop_transforms(zio);
2000 zio->io_stage = ZIO_STAGE_OPEN;
2001 BP_ZERO(bp);
2002 } else {
2003 zp->zp_dedup = 0;
2004 }
2005 zio->io_pipeline = ZIO_WRITE_PIPELINE;
2006 ddt_exit(ddt);
2007 return (ZIO_PIPELINE_CONTINUE);
2008 }
2009
2010 ditto_copies = ddt_ditto_copies_needed(ddt, dde, ddp);
2011 ASSERT(ditto_copies < SPA_DVAS_PER_BP);
2012
2013 if (ditto_copies > ddt_ditto_copies_present(dde) &&
2014 dde->dde_lead_zio[DDT_PHYS_DITTO] == NULL) {
2015 zio_prop_t czp = *zp;
2016
2017 czp.zp_copies = ditto_copies;
2018
2019 /*
2020 * If we arrived here with an override bp, we won't have run
2021 * the transform stack, so we won't have the data we need to
2022 * generate a child i/o. So, toss the override bp and restart.
2023 * This is safe, because using the override bp is just an
2024 * optimization; and it's rare, so the cost doesn't matter.
2025 */
2026 if (zio->io_bp_override) {
2027 zio_pop_transforms(zio);
2028 zio->io_stage = ZIO_STAGE_OPEN;
2029 zio->io_pipeline = ZIO_WRITE_PIPELINE;
2030 zio->io_bp_override = NULL;
2031 BP_ZERO(bp);
2032 ddt_exit(ddt);
2033 return (ZIO_PIPELINE_CONTINUE);
2034 }
2035
2036 dio = zio_write(zio, spa, txg, bp, zio->io_orig_data,
2037 zio->io_orig_size, &czp, NULL,
2038 zio_ddt_ditto_write_done, dde, zio->io_priority,
2039 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark);
2040
2041 zio_push_transform(dio, zio->io_data, zio->io_size, 0, NULL);
2042 dde->dde_lead_zio[DDT_PHYS_DITTO] = dio;
2043 }
2044
2045 if (ddp->ddp_phys_birth != 0 || dde->dde_lead_zio[p] != NULL) {
2046 if (ddp->ddp_phys_birth != 0)
2047 ddt_bp_fill(ddp, bp, txg);
2048 if (dde->dde_lead_zio[p] != NULL)
2049 zio_add_child(zio, dde->dde_lead_zio[p]);
2050 else
2051 ddt_phys_addref(ddp);
2052 } else if (zio->io_bp_override) {
2053 ASSERT(bp->blk_birth == txg);
2054 ASSERT(BP_EQUAL(bp, zio->io_bp_override));
2055 ddt_phys_fill(ddp, bp);
2056 ddt_phys_addref(ddp);
2057 } else {
2058 cio = zio_write(zio, spa, txg, bp, zio->io_orig_data,
2059 zio->io_orig_size, zp, zio_ddt_child_write_ready,
2060 zio_ddt_child_write_done, dde, zio->io_priority,
2061 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark);
2062
2063 zio_push_transform(cio, zio->io_data, zio->io_size, 0, NULL);
2064 dde->dde_lead_zio[p] = cio;
2065 }
2066
2067 ddt_exit(ddt);
2068
2069 if (cio)
2070 zio_nowait(cio);
2071 if (dio)
2072 zio_nowait(dio);
2073
2074 return (ZIO_PIPELINE_CONTINUE);
2075 }
2076
2077 ddt_entry_t *freedde; /* for debugging */
2078
2079 static int
2080 zio_ddt_free(zio_t *zio)
2081 {
2082 spa_t *spa = zio->io_spa;
2083 blkptr_t *bp = zio->io_bp;
2084 ddt_t *ddt = ddt_select(spa, bp);
2085 ddt_entry_t *dde;
2086 ddt_phys_t *ddp;
2087
2088 ASSERT(BP_GET_DEDUP(bp));
2089 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
2090
2091 ddt_enter(ddt);
2092 freedde = dde = ddt_lookup(ddt, bp, B_TRUE);
2093 ddp = ddt_phys_select(dde, bp);
2094 ddt_phys_decref(ddp);
2095 ddt_exit(ddt);
2096
2097 return (ZIO_PIPELINE_CONTINUE);
2098 }
2099
2100 /*
2101 * ==========================================================================
2102 * Allocate and free blocks
2103 * ==========================================================================
2104 */
2105 static int
2106 zio_dva_allocate(zio_t *zio)
2107 {
2108 spa_t *spa = zio->io_spa;
2109 metaslab_class_t *mc = spa_normal_class(spa);
2110 blkptr_t *bp = zio->io_bp;
2111 int error;
2112
2113 if (zio->io_gang_leader == NULL) {
2114 ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
2115 zio->io_gang_leader = zio;
2116 }
2117
2118 ASSERT(BP_IS_HOLE(bp));
2119 ASSERT3U(BP_GET_NDVAS(bp), ==, 0);
2120 ASSERT3U(zio->io_prop.zp_copies, >, 0);
2121 ASSERT3U(zio->io_prop.zp_copies, <=, spa_max_replication(spa));
2122 ASSERT3U(zio->io_size, ==, BP_GET_PSIZE(bp));
2123
2124 error = metaslab_alloc(spa, mc, zio->io_size, bp,
2125 zio->io_prop.zp_copies, zio->io_txg, NULL, 0);
2126
2127 if (error) {
2128 if (error == ENOSPC && zio->io_size > SPA_MINBLOCKSIZE)
2129 return (zio_write_gang_block(zio));
2130 zio->io_error = error;
2131 }
2132
2133 return (ZIO_PIPELINE_CONTINUE);
2134 }
2135
2136 static int
2137 zio_dva_free(zio_t *zio)
2138 {
2139 metaslab_free(zio->io_spa, zio->io_bp, zio->io_txg, B_FALSE);
2140
2141 return (ZIO_PIPELINE_CONTINUE);
2142 }
2143
2144 static int
2145 zio_dva_claim(zio_t *zio)
2146 {
2147 int error;
2148
2149 error = metaslab_claim(zio->io_spa, zio->io_bp, zio->io_txg);
2150 if (error)
2151 zio->io_error = error;
2152
2153 return (ZIO_PIPELINE_CONTINUE);
2154 }
2155
2156 /*
2157 * Undo an allocation. This is used by zio_done() when an I/O fails
2158 * and we want to give back the block we just allocated.
2159 * This handles both normal blocks and gang blocks.
2160 */
2161 static void
2162 zio_dva_unallocate(zio_t *zio, zio_gang_node_t *gn, blkptr_t *bp)
2163 {
2164 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp));
2165 ASSERT(zio->io_bp_override == NULL);
2166
2167 if (!BP_IS_HOLE(bp))
2168 metaslab_free(zio->io_spa, bp, bp->blk_birth, B_TRUE);
2169
2170 if (gn != NULL) {
2171 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
2172 zio_dva_unallocate(zio, gn->gn_child[g],
2173 &gn->gn_gbh->zg_blkptr[g]);
2174 }
2175 }
2176 }
2177
2178 /*
2179 * Try to allocate an intent log block. Return 0 on success, errno on failure.
2180 */
2181 int
2182 zio_alloc_zil(spa_t *spa, uint64_t txg, blkptr_t *new_bp, blkptr_t *old_bp,
2183 uint64_t size, boolean_t use_slog)
2184 {
2185 int error = 1;
2186
2187 ASSERT(txg > spa_syncing_txg(spa));
2188
2189 if (use_slog)
2190 error = metaslab_alloc(spa, spa_log_class(spa), size,
2191 new_bp, 1, txg, old_bp, METASLAB_HINTBP_AVOID);
2192
2193 if (error)
2194 error = metaslab_alloc(spa, spa_normal_class(spa), size,
2195 new_bp, 1, txg, old_bp, METASLAB_HINTBP_AVOID);
2196
2197 if (error == 0) {
2198 BP_SET_LSIZE(new_bp, size);
2199 BP_SET_PSIZE(new_bp, size);
2200 BP_SET_COMPRESS(new_bp, ZIO_COMPRESS_OFF);
2201 BP_SET_CHECKSUM(new_bp,
2202 spa_version(spa) >= SPA_VERSION_SLIM_ZIL
2203 ? ZIO_CHECKSUM_ZILOG2 : ZIO_CHECKSUM_ZILOG);
2204 BP_SET_TYPE(new_bp, DMU_OT_INTENT_LOG);
2205 BP_SET_LEVEL(new_bp, 0);
2206 BP_SET_DEDUP(new_bp, 0);
2207 BP_SET_BYTEORDER(new_bp, ZFS_HOST_BYTEORDER);
2208 }
2209
2210 return (error);
2211 }
2212
2213 /*
2214 * Free an intent log block.
2215 */
2216 void
2217 zio_free_zil(spa_t *spa, uint64_t txg, blkptr_t *bp)
2218 {
2219 ASSERT(BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG);
2220 ASSERT(!BP_IS_GANG(bp));
2221
2222 zio_free(spa, txg, bp);
2223 }
2224
2225 /*
2226 * ==========================================================================
2227 * Read and write to physical devices
2228 * ==========================================================================
2229 */
2230 static int
2231 zio_vdev_io_start(zio_t *zio)
2232 {
2233 vdev_t *vd = zio->io_vd;
2234 uint64_t align;
2235 spa_t *spa = zio->io_spa;
2236
2237 ASSERT(zio->io_error == 0);
2238 ASSERT(zio->io_child_error[ZIO_CHILD_VDEV] == 0);
2239
2240 if (vd == NULL) {
2241 if (!(zio->io_flags & ZIO_FLAG_CONFIG_WRITER))
2242 spa_config_enter(spa, SCL_ZIO, zio, RW_READER);
2243
2244 /*
2245 * The mirror_ops handle multiple DVAs in a single BP.
2246 */
2247 return (vdev_mirror_ops.vdev_op_io_start(zio));
2248 }
2249
2250 /*
2251 * We keep track of time-sensitive I/Os so that the scan thread
2252 * can quickly react to certain workloads. In particular, we care
2253 * about non-scrubbing, top-level reads and writes with the following
2254 * characteristics:
2255 * - synchronous writes of user data to non-slog devices
2256 * - any reads of user data
2257 * When these conditions are met, adjust the timestamp of spa_last_io
2258 * which allows the scan thread to adjust its workload accordingly.
2259 */
2260 if (!(zio->io_flags & ZIO_FLAG_SCAN_THREAD) && zio->io_bp != NULL &&
2261 vd == vd->vdev_top && !vd->vdev_islog &&
2262 zio->io_bookmark.zb_objset != DMU_META_OBJSET &&
2263 zio->io_txg != spa_syncing_txg(spa)) {
2264 uint64_t old = spa->spa_last_io;
2265 uint64_t new = ddi_get_lbolt64();
2266 if (old != new)
2267 (void) atomic_cas_64(&spa->spa_last_io, old, new);
2268 }
2269
2270 align = 1ULL << vd->vdev_top->vdev_ashift;
2271
2272 if (P2PHASE(zio->io_size, align) != 0) {
2273 uint64_t asize = P2ROUNDUP(zio->io_size, align);
2274 char *abuf = zio_buf_alloc(asize);
2275 ASSERT(vd == vd->vdev_top);
2276 if (zio->io_type == ZIO_TYPE_WRITE) {
2277 bcopy(zio->io_data, abuf, zio->io_size);
2278 bzero(abuf + zio->io_size, asize - zio->io_size);
2279 }
2280 zio_push_transform(zio, abuf, asize, asize, zio_subblock);
2281 }
2282
2283 ASSERT(P2PHASE(zio->io_offset, align) == 0);
2284 ASSERT(P2PHASE(zio->io_size, align) == 0);
2285 VERIFY(zio->io_type != ZIO_TYPE_WRITE || spa_writeable(spa));
2286
2287 /*
2288 * If this is a repair I/O, and there's no self-healing involved --
2289 * that is, we're just resilvering what we expect to resilver --
2290 * then don't do the I/O unless zio's txg is actually in vd's DTL.
2291 * This prevents spurious resilvering with nested replication.
2292 * For example, given a mirror of mirrors, (A+B)+(C+D), if only
2293 * A is out of date, we'll read from C+D, then use the data to
2294 * resilver A+B -- but we don't actually want to resilver B, just A.
2295 * The top-level mirror has no way to know this, so instead we just
2296 * discard unnecessary repairs as we work our way down the vdev tree.
2297 * The same logic applies to any form of nested replication:
2298 * ditto + mirror, RAID-Z + replacing, etc. This covers them all.
2299 */
2300 if ((zio->io_flags & ZIO_FLAG_IO_REPAIR) &&
2301 !(zio->io_flags & ZIO_FLAG_SELF_HEAL) &&
2302 zio->io_txg != 0 && /* not a delegated i/o */
2303 !vdev_dtl_contains(vd, DTL_PARTIAL, zio->io_txg, 1)) {
2304 ASSERT(zio->io_type == ZIO_TYPE_WRITE);
2305 zio_vdev_io_bypass(zio);
2306 return (ZIO_PIPELINE_CONTINUE);
2307 }
2308
2309 if (vd->vdev_ops->vdev_op_leaf &&
2310 (zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE)) {
2311
2312 if (zio->io_type == ZIO_TYPE_READ && vdev_cache_read(zio) == 0)
2313 return (ZIO_PIPELINE_CONTINUE);
2314
2315 if ((zio = vdev_queue_io(zio)) == NULL)
2316 return (ZIO_PIPELINE_STOP);
2317
2318 if (!vdev_accessible(vd, zio)) {
2319 zio->io_error = ENXIO;
2320 zio_interrupt(zio);
2321 return (ZIO_PIPELINE_STOP);
2322 }
2323 }
2324
2325 return (vd->vdev_ops->vdev_op_io_start(zio));
2326 }
2327
2328 static int
2329 zio_vdev_io_done(zio_t *zio)
2330 {
2331 vdev_t *vd = zio->io_vd;
2332 vdev_ops_t *ops = vd ? vd->vdev_ops : &vdev_mirror_ops;
2333 boolean_t unexpected_error = B_FALSE;
2334
2335 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE))
2336 return (ZIO_PIPELINE_STOP);
2337
2338 ASSERT(zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE);
2339
2340 if (vd != NULL && vd->vdev_ops->vdev_op_leaf) {
2341
2342 vdev_queue_io_done(zio);
2343
2344 if (zio->io_type == ZIO_TYPE_WRITE)
2345 vdev_cache_write(zio);
2346
2347 if (zio_injection_enabled && zio->io_error == 0)
2348 zio->io_error = zio_handle_device_injection(vd,
2349 zio, EIO);
2350
2351 if (zio_injection_enabled && zio->io_error == 0)
2352 zio->io_error = zio_handle_label_injection(zio, EIO);
2353
2354 if (zio->io_error) {
2355 if (!vdev_accessible(vd, zio)) {
2356 zio->io_error = ENXIO;
2357 } else {
2358 unexpected_error = B_TRUE;
2359 }
2360 }
2361 }
2362
2363 ops->vdev_op_io_done(zio);
2364
2365 if (unexpected_error)
2366 VERIFY(vdev_probe(vd, zio) == NULL);
2367
2368 return (ZIO_PIPELINE_CONTINUE);
2369 }
2370
2371 /*
2372 * For non-raidz ZIOs, we can just copy aside the bad data read from the
2373 * disk, and use that to finish the checksum ereport later.
2374 */
2375 static void
2376 zio_vsd_default_cksum_finish(zio_cksum_report_t *zcr,
2377 const void *good_buf)
2378 {
2379 /* no processing needed */
2380 zfs_ereport_finish_checksum(zcr, good_buf, zcr->zcr_cbdata, B_FALSE);
2381 }
2382
2383 /*ARGSUSED*/
2384 void
2385 zio_vsd_default_cksum_report(zio_t *zio, zio_cksum_report_t *zcr, void *ignored)
2386 {
2387 void *buf = zio_buf_alloc(zio->io_size);
2388
2389 bcopy(zio->io_data, buf, zio->io_size);
2390
2391 zcr->zcr_cbinfo = zio->io_size;
2392 zcr->zcr_cbdata = buf;
2393 zcr->zcr_finish = zio_vsd_default_cksum_finish;
2394 zcr->zcr_free = zio_buf_free;
2395 }
2396
2397 static int
2398 zio_vdev_io_assess(zio_t *zio)
2399 {
2400 vdev_t *vd = zio->io_vd;
2401
2402 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE))
2403 return (ZIO_PIPELINE_STOP);
2404
2405 if (vd == NULL && !(zio->io_flags & ZIO_FLAG_CONFIG_WRITER))
2406 spa_config_exit(zio->io_spa, SCL_ZIO, zio);
2407
2408 if (zio->io_vsd != NULL) {
2409 zio->io_vsd_ops->vsd_free(zio);
2410 zio->io_vsd = NULL;
2411 }
2412
2413 if (zio_injection_enabled && zio->io_error == 0)
2414 zio->io_error = zio_handle_fault_injection(zio, EIO);
2415
2416 /*
2417 * If the I/O failed, determine whether we should attempt to retry it.
2418 *
2419 * On retry, we cut in line in the issue queue, since we don't want
2420 * compression/checksumming/etc. work to prevent our (cheap) IO reissue.
2421 */
2422 if (zio->io_error && vd == NULL &&
2423 !(zio->io_flags & (ZIO_FLAG_DONT_RETRY | ZIO_FLAG_IO_RETRY))) {
2424 ASSERT(!(zio->io_flags & ZIO_FLAG_DONT_QUEUE)); /* not a leaf */
2425 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_BYPASS)); /* not a leaf */
2426 zio->io_error = 0;
2427 zio->io_flags |= ZIO_FLAG_IO_RETRY |
2428 ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE;
2429 zio->io_stage = ZIO_STAGE_VDEV_IO_START >> 1;
2430 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE,
2431 zio_requeue_io_start_cut_in_line);
2432 return (ZIO_PIPELINE_STOP);
2433 }
2434
2435 /*
2436 * If we got an error on a leaf device, convert it to ENXIO
2437 * if the device is not accessible at all.
2438 */
2439 if (zio->io_error && vd != NULL && vd->vdev_ops->vdev_op_leaf &&
2440 !vdev_accessible(vd, zio))
2441 zio->io_error = ENXIO;
2442
2443 /*
2444 * If we can't write to an interior vdev (mirror or RAID-Z),
2445 * set vdev_cant_write so that we stop trying to allocate from it.
2446 */
2447 if (zio->io_error == ENXIO && zio->io_type == ZIO_TYPE_WRITE &&
2448 vd != NULL && !vd->vdev_ops->vdev_op_leaf)
2449 vd->vdev_cant_write = B_TRUE;
2450
2451 if (zio->io_error)
2452 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
2453
2454 return (ZIO_PIPELINE_CONTINUE);
2455 }
2456
2457 void
2458 zio_vdev_io_reissue(zio_t *zio)
2459 {
2460 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START);
2461 ASSERT(zio->io_error == 0);
2462
2463 zio->io_stage >>= 1;
2464 }
2465
2466 void
2467 zio_vdev_io_redone(zio_t *zio)
2468 {
2469 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_DONE);
2470
2471 zio->io_stage >>= 1;
2472 }
2473
2474 void
2475 zio_vdev_io_bypass(zio_t *zio)
2476 {
2477 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START);
2478 ASSERT(zio->io_error == 0);
2479
2480 zio->io_flags |= ZIO_FLAG_IO_BYPASS;
2481 zio->io_stage = ZIO_STAGE_VDEV_IO_ASSESS >> 1;
2482 }
2483
2484 /*
2485 * ==========================================================================
2486 * Generate and verify checksums
2487 * ==========================================================================
2488 */
2489 static int
2490 zio_checksum_generate(zio_t *zio)
2491 {
2492 blkptr_t *bp = zio->io_bp;
2493 enum zio_checksum checksum;
2494
2495 if (bp == NULL) {
2496 /*
2497 * This is zio_write_phys().
2498 * We're either generating a label checksum, or none at all.
2499 */
2500 checksum = zio->io_prop.zp_checksum;
2501
2502 if (checksum == ZIO_CHECKSUM_OFF)
2503 return (ZIO_PIPELINE_CONTINUE);
2504
2505 ASSERT(checksum == ZIO_CHECKSUM_LABEL);
2506 } else {
2507 if (BP_IS_GANG(bp) && zio->io_child_type == ZIO_CHILD_GANG) {
2508 ASSERT(!IO_IS_ALLOCATING(zio));
2509 checksum = ZIO_CHECKSUM_GANG_HEADER;
2510 } else {
2511 checksum = BP_GET_CHECKSUM(bp);
2512 }
2513 }
2514
2515 zio_checksum_compute(zio, checksum, zio->io_data, zio->io_size);
2516
2517 return (ZIO_PIPELINE_CONTINUE);
2518 }
2519
2520 static int
2521 zio_checksum_verify(zio_t *zio)
2522 {
2523 zio_bad_cksum_t info;
2524 blkptr_t *bp = zio->io_bp;
2525 int error;
2526
2527 ASSERT(zio->io_vd != NULL);
2528
2529 if (bp == NULL) {
2530 /*
2531 * This is zio_read_phys().
2532 * We're either verifying a label checksum, or nothing at all.
2533 */
2534 if (zio->io_prop.zp_checksum == ZIO_CHECKSUM_OFF)
2535 return (ZIO_PIPELINE_CONTINUE);
2536
2537 ASSERT(zio->io_prop.zp_checksum == ZIO_CHECKSUM_LABEL);
2538 }
2539
2540 if ((error = zio_checksum_error(zio, &info)) != 0) {
2541 zio->io_error = error;
2542 if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) {
2543 zfs_ereport_start_checksum(zio->io_spa,
2544 zio->io_vd, zio, zio->io_offset,
2545 zio->io_size, NULL, &info);
2546 }
2547 }
2548
2549 return (ZIO_PIPELINE_CONTINUE);
2550 }
2551
2552 /*
2553 * Called by RAID-Z to ensure we don't compute the checksum twice.
2554 */
2555 void
2556 zio_checksum_verified(zio_t *zio)
2557 {
2558 zio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY;
2559 }
2560
2561 /*
2562 * ==========================================================================
2563 * Error rank. Error are ranked in the order 0, ENXIO, ECKSUM, EIO, other.
2564 * An error of 0 indictes success. ENXIO indicates whole-device failure,
2565 * which may be transient (e.g. unplugged) or permament. ECKSUM and EIO
2566 * indicate errors that are specific to one I/O, and most likely permanent.
2567 * Any other error is presumed to be worse because we weren't expecting it.
2568 * ==========================================================================
2569 */
2570 int
2571 zio_worst_error(int e1, int e2)
2572 {
2573 static int zio_error_rank[] = { 0, ENXIO, ECKSUM, EIO };
2574 int r1, r2;
2575
2576 for (r1 = 0; r1 < sizeof (zio_error_rank) / sizeof (int); r1++)
2577 if (e1 == zio_error_rank[r1])
2578 break;
2579
2580 for (r2 = 0; r2 < sizeof (zio_error_rank) / sizeof (int); r2++)
2581 if (e2 == zio_error_rank[r2])
2582 break;
2583
2584 return (r1 > r2 ? e1 : e2);
2585 }
2586
2587 /*
2588 * ==========================================================================
2589 * I/O completion
2590 * ==========================================================================
2591 */
2592 static int
2593 zio_ready(zio_t *zio)
2594 {
2595 blkptr_t *bp = zio->io_bp;
2596 zio_t *pio, *pio_next;
2597
2598 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) ||
2599 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_READY))
2600 return (ZIO_PIPELINE_STOP);
2601
2602 if (zio->io_ready) {
2603 ASSERT(IO_IS_ALLOCATING(zio));
2604 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp));
2605 ASSERT(zio->io_children[ZIO_CHILD_GANG][ZIO_WAIT_READY] == 0);
2606
2607 zio->io_ready(zio);
2608 }
2609
2610 if (bp != NULL && bp != &zio->io_bp_copy)
2611 zio->io_bp_copy = *bp;
2612
2613 if (zio->io_error)
2614 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
2615
2616 mutex_enter(&zio->io_lock);
2617 zio->io_state[ZIO_WAIT_READY] = 1;
2618 pio = zio_walk_parents(zio);
2619 mutex_exit(&zio->io_lock);
2620
2621 /*
2622 * As we notify zio's parents, new parents could be added.
2623 * New parents go to the head of zio's io_parent_list, however,
2624 * so we will (correctly) not notify them. The remainder of zio's
2625 * io_parent_list, from 'pio_next' onward, cannot change because
2626 * all parents must wait for us to be done before they can be done.
2627 */
2628 for (; pio != NULL; pio = pio_next) {
2629 pio_next = zio_walk_parents(zio);
2630 zio_notify_parent(pio, zio, ZIO_WAIT_READY);
2631 }
2632
2633 if (zio->io_flags & ZIO_FLAG_NODATA) {
2634 if (BP_IS_GANG(bp)) {
2635 zio->io_flags &= ~ZIO_FLAG_NODATA;
2636 } else {
2637 ASSERT((uintptr_t)zio->io_data < SPA_MAXBLOCKSIZE);
2638 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES;
2639 }
2640 }
2641
2642 if (zio_injection_enabled &&
2643 zio->io_spa->spa_syncing_txg == zio->io_txg)
2644 zio_handle_ignored_writes(zio);
2645
2646 return (ZIO_PIPELINE_CONTINUE);
2647 }
2648
2649 static int
2650 zio_done(zio_t *zio)
2651 {
2652 spa_t *spa = zio->io_spa;
2653 zio_t *lio = zio->io_logical;
2654 blkptr_t *bp = zio->io_bp;
2655 vdev_t *vd = zio->io_vd;
2656 uint64_t psize = zio->io_size;
2657 zio_t *pio, *pio_next;
2658
2659 /*
2660 * If our children haven't all completed,
2661 * wait for them and then repeat this pipeline stage.
2662 */
2663 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE) ||
2664 zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE) ||
2665 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE) ||
2666 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_DONE))
2667 return (ZIO_PIPELINE_STOP);
2668
2669 for (int c = 0; c < ZIO_CHILD_TYPES; c++)
2670 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
2671 ASSERT(zio->io_children[c][w] == 0);
2672
2673 if (bp != NULL) {
2674 ASSERT(bp->blk_pad[0] == 0);
2675 ASSERT(bp->blk_pad[1] == 0);
2676 ASSERT(bcmp(bp, &zio->io_bp_copy, sizeof (blkptr_t)) == 0 ||
2677 (bp == zio_unique_parent(zio)->io_bp));
2678 if (zio->io_type == ZIO_TYPE_WRITE && !BP_IS_HOLE(bp) &&
2679 zio->io_bp_override == NULL &&
2680 !(zio->io_flags & ZIO_FLAG_IO_REPAIR)) {
2681 ASSERT(!BP_SHOULD_BYTESWAP(bp));
2682 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(bp));
2683 ASSERT(BP_COUNT_GANG(bp) == 0 ||
2684 (BP_COUNT_GANG(bp) == BP_GET_NDVAS(bp)));
2685 }
2686 }
2687
2688 /*
2689 * If there were child vdev/gang/ddt errors, they apply to us now.
2690 */
2691 zio_inherit_child_errors(zio, ZIO_CHILD_VDEV);
2692 zio_inherit_child_errors(zio, ZIO_CHILD_GANG);
2693 zio_inherit_child_errors(zio, ZIO_CHILD_DDT);
2694
2695 /*
2696 * If the I/O on the transformed data was successful, generate any
2697 * checksum reports now while we still have the transformed data.
2698 */
2699 if (zio->io_error == 0) {
2700 while (zio->io_cksum_report != NULL) {
2701 zio_cksum_report_t *zcr = zio->io_cksum_report;
2702 uint64_t align = zcr->zcr_align;
2703 uint64_t asize = P2ROUNDUP(psize, align);
2704 char *abuf = zio->io_data;
2705
2706 if (asize != psize) {
2707 abuf = zio_buf_alloc(asize);
2708 bcopy(zio->io_data, abuf, psize);
2709 bzero(abuf + psize, asize - psize);
2710 }
2711
2712 zio->io_cksum_report = zcr->zcr_next;
2713 zcr->zcr_next = NULL;
2714 zcr->zcr_finish(zcr, abuf);
2715 zfs_ereport_free_checksum(zcr);
2716
2717 if (asize != psize)
2718 zio_buf_free(abuf, asize);
2719 }
2720 }
2721
2722 zio_pop_transforms(zio); /* note: may set zio->io_error */
2723
2724 vdev_stat_update(zio, psize);
2725
2726 if (zio->io_error) {
2727 /*
2728 * If this I/O is attached to a particular vdev,
2729 * generate an error message describing the I/O failure
2730 * at the block level. We ignore these errors if the
2731 * device is currently unavailable.
2732 */
2733 if (zio->io_error != ECKSUM && vd != NULL && !vdev_is_dead(vd))
2734 zfs_ereport_post(FM_EREPORT_ZFS_IO, spa, vd, zio, 0, 0);
2735
2736 if ((zio->io_error == EIO || !(zio->io_flags &
2737 (ZIO_FLAG_SPECULATIVE | ZIO_FLAG_DONT_PROPAGATE))) &&
2738 zio == lio) {
2739 /*
2740 * For logical I/O requests, tell the SPA to log the
2741 * error and generate a logical data ereport.
2742 */
2743 spa_log_error(spa, zio);
2744 zfs_ereport_post(FM_EREPORT_ZFS_DATA, spa, NULL, zio,
2745 0, 0);
2746 }
2747 }
2748
2749 if (zio->io_error && zio == lio) {
2750 /*
2751 * Determine whether zio should be reexecuted. This will
2752 * propagate all the way to the root via zio_notify_parent().
2753 */
2754 ASSERT(vd == NULL && bp != NULL);
2755 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
2756
2757 if (IO_IS_ALLOCATING(zio) &&
2758 !(zio->io_flags & ZIO_FLAG_CANFAIL)) {
2759 if (zio->io_error != ENOSPC)
2760 zio->io_reexecute |= ZIO_REEXECUTE_NOW;
2761 else
2762 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
2763 }
2764
2765 if ((zio->io_type == ZIO_TYPE_READ ||
2766 zio->io_type == ZIO_TYPE_FREE) &&
2767 !(zio->io_flags & ZIO_FLAG_SCAN_THREAD) &&
2768 zio->io_error == ENXIO &&
2769 spa_load_state(spa) == SPA_LOAD_NONE &&
2770 spa_get_failmode(spa) != ZIO_FAILURE_MODE_CONTINUE)
2771 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
2772
2773 if (!(zio->io_flags & ZIO_FLAG_CANFAIL) && !zio->io_reexecute)
2774 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
2775
2776 /*
2777 * Here is a possibly good place to attempt to do
2778 * either combinatorial reconstruction or error correction
2779 * based on checksums. It also might be a good place
2780 * to send out preliminary ereports before we suspend
2781 * processing.
2782 */
2783 }
2784
2785 /*
2786 * If there were logical child errors, they apply to us now.
2787 * We defer this until now to avoid conflating logical child
2788 * errors with errors that happened to the zio itself when
2789 * updating vdev stats and reporting FMA events above.
2790 */
2791 zio_inherit_child_errors(zio, ZIO_CHILD_LOGICAL);
2792
2793 if ((zio->io_error || zio->io_reexecute) &&
2794 IO_IS_ALLOCATING(zio) && zio->io_gang_leader == zio &&
2795 !(zio->io_flags & ZIO_FLAG_IO_REWRITE))
2796 zio_dva_unallocate(zio, zio->io_gang_tree, bp);
2797
2798 zio_gang_tree_free(&zio->io_gang_tree);
2799
2800 /*
2801 * Godfather I/Os should never suspend.
2802 */
2803 if ((zio->io_flags & ZIO_FLAG_GODFATHER) &&
2804 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND))
2805 zio->io_reexecute = 0;
2806
2807 if (zio->io_reexecute) {
2808 /*
2809 * This is a logical I/O that wants to reexecute.
2810 *
2811 * Reexecute is top-down. When an i/o fails, if it's not
2812 * the root, it simply notifies its parent and sticks around.
2813 * The parent, seeing that it still has children in zio_done(),
2814 * does the same. This percolates all the way up to the root.
2815 * The root i/o will reexecute or suspend the entire tree.
2816 *
2817 * This approach ensures that zio_reexecute() honors
2818 * all the original i/o dependency relationships, e.g.
2819 * parents not executing until children are ready.
2820 */
2821 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
2822
2823 zio->io_gang_leader = NULL;
2824
2825 mutex_enter(&zio->io_lock);
2826 zio->io_state[ZIO_WAIT_DONE] = 1;
2827 mutex_exit(&zio->io_lock);
2828
2829 /*
2830 * "The Godfather" I/O monitors its children but is
2831 * not a true parent to them. It will track them through
2832 * the pipeline but severs its ties whenever they get into
2833 * trouble (e.g. suspended). This allows "The Godfather"
2834 * I/O to return status without blocking.
2835 */
2836 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) {
2837 zio_link_t *zl = zio->io_walk_link;
2838 pio_next = zio_walk_parents(zio);
2839
2840 if ((pio->io_flags & ZIO_FLAG_GODFATHER) &&
2841 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND)) {
2842 zio_remove_child(pio, zio, zl);
2843 zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
2844 }
2845 }
2846
2847 if ((pio = zio_unique_parent(zio)) != NULL) {
2848 /*
2849 * We're not a root i/o, so there's nothing to do
2850 * but notify our parent. Don't propagate errors
2851 * upward since we haven't permanently failed yet.
2852 */
2853 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER));
2854 zio->io_flags |= ZIO_FLAG_DONT_PROPAGATE;
2855 zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
2856 } else if (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND) {
2857 /*
2858 * We'd fail again if we reexecuted now, so suspend
2859 * until conditions improve (e.g. device comes online).
2860 */
2861 zio_suspend(spa, zio);
2862 } else {
2863 /*
2864 * Reexecution is potentially a huge amount of work.
2865 * Hand it off to the otherwise-unused claim taskq.
2866 */
2867 (void) taskq_dispatch(
2868 spa->spa_zio_taskq[ZIO_TYPE_CLAIM][ZIO_TASKQ_ISSUE],
2869 (task_func_t *)zio_reexecute, zio, TQ_SLEEP);
2870 }
2871 return (ZIO_PIPELINE_STOP);
2872 }
2873
2874 ASSERT(zio->io_child_count == 0);
2875 ASSERT(zio->io_reexecute == 0);
2876 ASSERT(zio->io_error == 0 || (zio->io_flags & ZIO_FLAG_CANFAIL));
2877
2878 /*
2879 * Report any checksum errors, since the I/O is complete.
2880 */
2881 while (zio->io_cksum_report != NULL) {
2882 zio_cksum_report_t *zcr = zio->io_cksum_report;
2883 zio->io_cksum_report = zcr->zcr_next;
2884 zcr->zcr_next = NULL;
2885 zcr->zcr_finish(zcr, NULL);
2886 zfs_ereport_free_checksum(zcr);
2887 }
2888
2889 /*
2890 * It is the responsibility of the done callback to ensure that this
2891 * particular zio is no longer discoverable for adoption, and as
2892 * such, cannot acquire any new parents.
2893 */
2894 if (zio->io_done)
2895 zio->io_done(zio);
2896
2897 mutex_enter(&zio->io_lock);
2898 zio->io_state[ZIO_WAIT_DONE] = 1;
2899 mutex_exit(&zio->io_lock);
2900
2901 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) {
2902 zio_link_t *zl = zio->io_walk_link;
2903 pio_next = zio_walk_parents(zio);
2904 zio_remove_child(pio, zio, zl);
2905 zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
2906 }
2907
2908 if (zio->io_waiter != NULL) {
2909 mutex_enter(&zio->io_lock);
2910 zio->io_executor = NULL;
2911 cv_broadcast(&zio->io_cv);
2912 mutex_exit(&zio->io_lock);
2913 } else {
2914 zio_destroy(zio);
2915 }
2916
2917 return (ZIO_PIPELINE_STOP);
2918 }
2919
2920 /*
2921 * ==========================================================================
2922 * I/O pipeline definition
2923 * ==========================================================================
2924 */
2925 static zio_pipe_stage_t *zio_pipeline[] = {
2926 NULL,
2927 zio_read_bp_init,
2928 zio_free_bp_init,
2929 zio_issue_async,
2930 zio_write_bp_init,
2931 zio_checksum_generate,
2932 zio_ddt_read_start,
2933 zio_ddt_read_done,
2934 zio_ddt_write,
2935 zio_ddt_free,
2936 zio_gang_assemble,
2937 zio_gang_issue,
2938 zio_dva_allocate,
2939 zio_dva_free,
2940 zio_dva_claim,
2941 zio_ready,
2942 zio_vdev_io_start,
2943 zio_vdev_io_done,
2944 zio_vdev_io_assess,
2945 zio_checksum_verify,
2946 zio_done
2947 };
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