1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2013 by Delphix. All rights reserved.
24 * Copyright (c) 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 type descriptions
43 * ==========================================================================
44 */
45 const char *zio_type_name[ZIO_TYPES] = {
46 "zio_null", "zio_read", "zio_write", "zio_free", "zio_claim",
47 "zio_ioctl"
48 };
49
50 /*
51 * ==========================================================================
52 * I/O kmem caches
53 * ==========================================================================
54 */
55 kmem_cache_t *zio_cache;
56 kmem_cache_t *zio_link_cache;
57 kmem_cache_t *zio_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
58 kmem_cache_t *zio_data_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
59
60 #ifdef _KERNEL
61 extern vmem_t *zio_alloc_arena;
62 #endif
63 extern int zfs_mg_alloc_failures;
64
65 /*
66 * The following actions directly effect the spa's sync-to-convergence logic.
67 * The values below define the sync pass when we start performing the action.
68 * Care should be taken when changing these values as they directly impact
69 * spa_sync() performance. Tuning these values may introduce subtle performance
70 * pathologies and should only be done in the context of performance analysis.
71 * These tunables will eventually be removed and replaced with #defines once
72 * enough analysis has been done to determine optimal values.
73 *
74 * The 'zfs_sync_pass_deferred_free' pass must be greater than 1 to ensure that
75 * regular blocks are not deferred.
76 */
77 int zfs_sync_pass_deferred_free = 2; /* defer frees starting in this pass */
78 int zfs_sync_pass_dont_compress = 5; /* don't compress starting in this pass */
79 int zfs_sync_pass_rewrite = 2; /* rewrite new bps starting in this pass */
80
81 /*
82 * An allocating zio is one that either currently has the DVA allocate
83 * stage set or will have it later in its lifetime.
84 */
85 #define IO_IS_ALLOCATING(zio) ((zio)->io_orig_pipeline & ZIO_STAGE_DVA_ALLOCATE)
86
87 boolean_t zio_requeue_io_start_cut_in_line = B_TRUE;
88
89 #ifdef ZFS_DEBUG
90 int zio_buf_debug_limit = 16384;
91 #else
92 int zio_buf_debug_limit = 0;
93 #endif
94
95 void
96 zio_init(void)
97 {
98 size_t c;
99 vmem_t *data_alloc_arena = NULL;
100
101 #ifdef _KERNEL
102 data_alloc_arena = zio_alloc_arena;
103 #endif
104 zio_cache = kmem_cache_create("zio_cache",
105 sizeof (zio_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
106 zio_link_cache = kmem_cache_create("zio_link_cache",
107 sizeof (zio_link_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
108
109 /*
110 * For small buffers, we want a cache for each multiple of
111 * SPA_MINBLOCKSIZE. For medium-size buffers, we want a cache
112 * for each quarter-power of 2. For large buffers, we want
113 * a cache for each multiple of PAGESIZE.
114 */
115 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) {
116 size_t size = (c + 1) << SPA_MINBLOCKSHIFT;
117 size_t p2 = size;
118 size_t align = 0;
119 size_t cflags = (size > zio_buf_debug_limit) ? KMC_NODEBUG : 0;
120
121 while (p2 & (p2 - 1))
122 p2 &= p2 - 1;
123
124 #ifndef _KERNEL
125 /*
126 * If we are using watchpoints, put each buffer on its own page,
127 * to eliminate the performance overhead of trapping to the
128 * kernel when modifying a non-watched buffer that shares the
129 * page with a watched buffer.
130 */
131 if (arc_watch && !IS_P2ALIGNED(size, PAGESIZE))
132 continue;
133 #endif
134 if (size <= 4 * SPA_MINBLOCKSIZE) {
135 align = SPA_MINBLOCKSIZE;
136 } else if (IS_P2ALIGNED(size, PAGESIZE)) {
137 align = PAGESIZE;
138 } else if (IS_P2ALIGNED(size, p2 >> 2)) {
139 align = p2 >> 2;
140 }
141
142 if (align != 0) {
143 char name[36];
144 (void) sprintf(name, "zio_buf_%lu", (ulong_t)size);
145 zio_buf_cache[c] = kmem_cache_create(name, size,
146 align, NULL, NULL, NULL, NULL, NULL, cflags);
147
148 /*
149 * Since zio_data bufs do not appear in crash dumps, we
150 * pass KMC_NOTOUCH so that no allocator metadata is
151 * stored with the buffers.
152 */
153 (void) sprintf(name, "zio_data_buf_%lu", (ulong_t)size);
154 zio_data_buf_cache[c] = kmem_cache_create(name, size,
155 align, NULL, NULL, NULL, NULL, data_alloc_arena,
156 cflags | KMC_NOTOUCH);
157 }
158 }
159
160 while (--c != 0) {
161 ASSERT(zio_buf_cache[c] != NULL);
162 if (zio_buf_cache[c - 1] == NULL)
163 zio_buf_cache[c - 1] = zio_buf_cache[c];
164
165 ASSERT(zio_data_buf_cache[c] != NULL);
166 if (zio_data_buf_cache[c - 1] == NULL)
167 zio_data_buf_cache[c - 1] = zio_data_buf_cache[c];
168 }
169
170 /*
171 * The zio write taskqs have 1 thread per cpu, allow 1/2 of the taskqs
172 * to fail 3 times per txg or 8 failures, whichever is greater.
173 */
174 zfs_mg_alloc_failures = MAX((3 * max_ncpus / 2), 8);
175
176 zio_inject_init();
177 }
178
179 void
180 zio_fini(void)
181 {
182 size_t c;
183 kmem_cache_t *last_cache = NULL;
184 kmem_cache_t *last_data_cache = NULL;
185
186 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) {
187 if (zio_buf_cache[c] != last_cache) {
188 last_cache = zio_buf_cache[c];
189 kmem_cache_destroy(zio_buf_cache[c]);
190 }
191 zio_buf_cache[c] = NULL;
192
193 if (zio_data_buf_cache[c] != last_data_cache) {
194 last_data_cache = zio_data_buf_cache[c];
195 kmem_cache_destroy(zio_data_buf_cache[c]);
196 }
197 zio_data_buf_cache[c] = NULL;
198 }
199
200 kmem_cache_destroy(zio_link_cache);
201 kmem_cache_destroy(zio_cache);
202
203 zio_inject_fini();
204 }
205
206 /*
207 * ==========================================================================
208 * Allocate and free I/O buffers
209 * ==========================================================================
210 */
211
212 /*
213 * Use zio_buf_alloc to allocate ZFS metadata. This data will appear in a
214 * crashdump if the kernel panics, so use it judiciously. Obviously, it's
215 * useful to inspect ZFS metadata, but if possible, we should avoid keeping
216 * excess / transient data in-core during a crashdump.
217 */
218 void *
219 zio_buf_alloc(size_t size)
220 {
221 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
222
223 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
224
225 return (kmem_cache_alloc(zio_buf_cache[c], KM_PUSHPAGE));
226 }
227
228 /*
229 * Use zio_data_buf_alloc to allocate data. The data will not appear in a
230 * crashdump if the kernel panics. This exists so that we will limit the amount
231 * of ZFS data that shows up in a kernel crashdump. (Thus reducing the amount
232 * of kernel heap dumped to disk when the kernel panics)
233 */
234 void *
235 zio_data_buf_alloc(size_t size)
236 {
237 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
238
239 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
240
241 return (kmem_cache_alloc(zio_data_buf_cache[c], KM_PUSHPAGE));
242 }
243
244 void
245 zio_buf_free(void *buf, size_t size)
246 {
247 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
248
249 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
250
251 kmem_cache_free(zio_buf_cache[c], buf);
252 }
253
254 void
255 zio_data_buf_free(void *buf, size_t size)
256 {
257 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
258
259 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
260
261 kmem_cache_free(zio_data_buf_cache[c], buf);
262 }
263
264 /*
265 * ==========================================================================
266 * Push and pop I/O transform buffers
267 * ==========================================================================
268 */
269 static void
270 zio_push_transform(zio_t *zio, void *data, uint64_t size, uint64_t bufsize,
271 zio_transform_func_t *transform)
272 {
273 zio_transform_t *zt = kmem_alloc(sizeof (zio_transform_t), KM_SLEEP);
274
275 zt->zt_orig_data = zio->io_data;
276 zt->zt_orig_size = zio->io_size;
277 zt->zt_bufsize = bufsize;
278 zt->zt_transform = transform;
279
280 zt->zt_next = zio->io_transform_stack;
281 zio->io_transform_stack = zt;
282
283 zio->io_data = data;
284 zio->io_size = size;
285 }
286
287 static void
288 zio_pop_transforms(zio_t *zio)
289 {
290 zio_transform_t *zt;
291
292 while ((zt = zio->io_transform_stack) != NULL) {
293 if (zt->zt_transform != NULL)
294 zt->zt_transform(zio,
295 zt->zt_orig_data, zt->zt_orig_size);
296
297 if (zt->zt_bufsize != 0)
298 zio_buf_free(zio->io_data, zt->zt_bufsize);
299
300 zio->io_data = zt->zt_orig_data;
301 zio->io_size = zt->zt_orig_size;
302 zio->io_transform_stack = zt->zt_next;
303
304 kmem_free(zt, sizeof (zio_transform_t));
305 }
306 }
307
308 /*
309 * ==========================================================================
310 * I/O transform callbacks for subblocks and decompression
311 * ==========================================================================
312 */
313 static void
314 zio_subblock(zio_t *zio, void *data, uint64_t size)
315 {
316 ASSERT(zio->io_size > size);
317
318 if (zio->io_type == ZIO_TYPE_READ)
319 bcopy(zio->io_data, data, size);
320 }
321
322 static void
323 zio_decompress(zio_t *zio, void *data, uint64_t size)
324 {
325 if (zio->io_error == 0 &&
326 zio_decompress_data(BP_GET_COMPRESS(zio->io_bp),
327 zio->io_data, data, zio->io_size, size) != 0)
328 zio->io_error = SET_ERROR(EIO);
329 }
330
331 /*
332 * ==========================================================================
333 * I/O parent/child relationships and pipeline interlocks
334 * ==========================================================================
335 */
336 /*
337 * NOTE - Callers to zio_walk_parents() and zio_walk_children must
338 * continue calling these functions until they return NULL.
339 * Otherwise, the next caller will pick up the list walk in
340 * some indeterminate state. (Otherwise every caller would
341 * have to pass in a cookie to keep the state represented by
342 * io_walk_link, which gets annoying.)
343 */
344 zio_t *
345 zio_walk_parents(zio_t *cio)
346 {
347 zio_link_t *zl = cio->io_walk_link;
348 list_t *pl = &cio->io_parent_list;
349
350 zl = (zl == NULL) ? list_head(pl) : list_next(pl, zl);
351 cio->io_walk_link = zl;
352
353 if (zl == NULL)
354 return (NULL);
355
356 ASSERT(zl->zl_child == cio);
357 return (zl->zl_parent);
358 }
359
360 zio_t *
361 zio_walk_children(zio_t *pio)
362 {
363 zio_link_t *zl = pio->io_walk_link;
364 list_t *cl = &pio->io_child_list;
365
366 zl = (zl == NULL) ? list_head(cl) : list_next(cl, zl);
367 pio->io_walk_link = zl;
368
369 if (zl == NULL)
370 return (NULL);
371
372 ASSERT(zl->zl_parent == pio);
373 return (zl->zl_child);
374 }
375
376 zio_t *
377 zio_unique_parent(zio_t *cio)
378 {
379 zio_t *pio = zio_walk_parents(cio);
380
381 VERIFY(zio_walk_parents(cio) == NULL);
382 return (pio);
383 }
384
385 void
386 zio_add_child(zio_t *pio, zio_t *cio)
387 {
388 zio_link_t *zl = kmem_cache_alloc(zio_link_cache, KM_SLEEP);
389
390 /*
391 * Logical I/Os can have logical, gang, or vdev children.
392 * Gang I/Os can have gang or vdev children.
393 * Vdev I/Os can only have vdev children.
394 * The following ASSERT captures all of these constraints.
395 */
396 ASSERT(cio->io_child_type <= pio->io_child_type);
397
398 zl->zl_parent = pio;
399 zl->zl_child = cio;
400
401 mutex_enter(&cio->io_lock);
402 mutex_enter(&pio->io_lock);
403
404 ASSERT(pio->io_state[ZIO_WAIT_DONE] == 0);
405
406 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
407 pio->io_children[cio->io_child_type][w] += !cio->io_state[w];
408
409 list_insert_head(&pio->io_child_list, zl);
410 list_insert_head(&cio->io_parent_list, zl);
411
412 pio->io_child_count++;
413 cio->io_parent_count++;
414
415 mutex_exit(&pio->io_lock);
416 mutex_exit(&cio->io_lock);
417 }
418
419 static void
420 zio_remove_child(zio_t *pio, zio_t *cio, zio_link_t *zl)
421 {
422 ASSERT(zl->zl_parent == pio);
423 ASSERT(zl->zl_child == cio);
424
425 mutex_enter(&cio->io_lock);
426 mutex_enter(&pio->io_lock);
427
428 list_remove(&pio->io_child_list, zl);
429 list_remove(&cio->io_parent_list, zl);
430
431 pio->io_child_count--;
432 cio->io_parent_count--;
433
434 mutex_exit(&pio->io_lock);
435 mutex_exit(&cio->io_lock);
436
437 kmem_cache_free(zio_link_cache, zl);
438 }
439
440 static boolean_t
441 zio_wait_for_children(zio_t *zio, enum zio_child child, enum zio_wait_type wait)
442 {
443 uint64_t *countp = &zio->io_children[child][wait];
444 boolean_t waiting = B_FALSE;
445
446 mutex_enter(&zio->io_lock);
447 ASSERT(zio->io_stall == NULL);
448 if (*countp != 0) {
449 zio->io_stage >>= 1;
450 zio->io_stall = countp;
451 waiting = B_TRUE;
452 }
453 mutex_exit(&zio->io_lock);
454
455 return (waiting);
456 }
457
458 static void
459 zio_notify_parent(zio_t *pio, zio_t *zio, enum zio_wait_type wait)
460 {
461 uint64_t *countp = &pio->io_children[zio->io_child_type][wait];
462 int *errorp = &pio->io_child_error[zio->io_child_type];
463
464 mutex_enter(&pio->io_lock);
465 if (zio->io_error && !(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE))
466 *errorp = zio_worst_error(*errorp, zio->io_error);
467 pio->io_reexecute |= zio->io_reexecute;
468 ASSERT3U(*countp, >, 0);
469
470 (*countp)--;
471
472 if (*countp == 0 && pio->io_stall == countp) {
473 pio->io_stall = NULL;
474 mutex_exit(&pio->io_lock);
475 zio_execute(pio);
476 } else {
477 mutex_exit(&pio->io_lock);
478 }
479 }
480
481 static void
482 zio_inherit_child_errors(zio_t *zio, enum zio_child c)
483 {
484 if (zio->io_child_error[c] != 0 && zio->io_error == 0)
485 zio->io_error = zio->io_child_error[c];
486 }
487
488 /*
489 * ==========================================================================
490 * Create the various types of I/O (read, write, free, etc)
491 * ==========================================================================
492 */
493 static zio_t *
494 zio_create(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
495 void *data, uint64_t size, zio_done_func_t *done, void *private,
496 zio_type_t type, zio_priority_t priority, enum zio_flag flags,
497 vdev_t *vd, uint64_t offset, const zbookmark_t *zb,
498 enum zio_stage stage, enum zio_stage pipeline)
499 {
500 zio_t *zio;
501
502 ASSERT3U(size, <=, SPA_MAXBLOCKSIZE);
503 ASSERT(P2PHASE(size, SPA_MINBLOCKSIZE) == 0);
504 ASSERT(P2PHASE(offset, SPA_MINBLOCKSIZE) == 0);
505
506 ASSERT(!vd || spa_config_held(spa, SCL_STATE_ALL, RW_READER));
507 ASSERT(!bp || !(flags & ZIO_FLAG_CONFIG_WRITER));
508 ASSERT(vd || stage == ZIO_STAGE_OPEN);
509
510 zio = kmem_cache_alloc(zio_cache, KM_SLEEP);
511 bzero(zio, sizeof (zio_t));
512
513 mutex_init(&zio->io_lock, NULL, MUTEX_DEFAULT, NULL);
514 cv_init(&zio->io_cv, NULL, CV_DEFAULT, NULL);
515
516 list_create(&zio->io_parent_list, sizeof (zio_link_t),
517 offsetof(zio_link_t, zl_parent_node));
518 list_create(&zio->io_child_list, sizeof (zio_link_t),
519 offsetof(zio_link_t, zl_child_node));
520
521 if (vd != NULL)
522 zio->io_child_type = ZIO_CHILD_VDEV;
523 else if (flags & ZIO_FLAG_GANG_CHILD)
524 zio->io_child_type = ZIO_CHILD_GANG;
525 else if (flags & ZIO_FLAG_DDT_CHILD)
526 zio->io_child_type = ZIO_CHILD_DDT;
527 else
528 zio->io_child_type = ZIO_CHILD_LOGICAL;
529
530 if (bp != NULL) {
531 zio->io_bp = (blkptr_t *)bp;
532 zio->io_bp_copy = *bp;
533 zio->io_bp_orig = *bp;
534 if (type != ZIO_TYPE_WRITE ||
535 zio->io_child_type == ZIO_CHILD_DDT)
536 zio->io_bp = &zio->io_bp_copy; /* so caller can free */
537 if (zio->io_child_type == ZIO_CHILD_LOGICAL)
538 zio->io_logical = zio;
539 if (zio->io_child_type > ZIO_CHILD_GANG && BP_IS_GANG(bp))
540 pipeline |= ZIO_GANG_STAGES;
541 }
542
543 zio->io_spa = spa;
544 zio->io_txg = txg;
545 zio->io_done = done;
546 zio->io_private = private;
547 zio->io_type = type;
548 zio->io_priority = priority;
549 zio->io_vd = vd;
550 zio->io_offset = offset;
551 zio->io_orig_data = zio->io_data = data;
552 zio->io_orig_size = zio->io_size = size;
553 zio->io_orig_flags = zio->io_flags = flags;
554 zio->io_orig_stage = zio->io_stage = stage;
555 zio->io_orig_pipeline = zio->io_pipeline = pipeline;
556
557 zio->io_state[ZIO_WAIT_READY] = (stage >= ZIO_STAGE_READY);
558 zio->io_state[ZIO_WAIT_DONE] = (stage >= ZIO_STAGE_DONE);
559
560 if (zb != NULL)
561 zio->io_bookmark = *zb;
562
563 if (pio != NULL) {
564 if (zio->io_logical == NULL)
565 zio->io_logical = pio->io_logical;
566 if (zio->io_child_type == ZIO_CHILD_GANG)
567 zio->io_gang_leader = pio->io_gang_leader;
568 zio_add_child(pio, zio);
569 }
570
571 return (zio);
572 }
573
574 static void
575 zio_destroy(zio_t *zio)
576 {
577 list_destroy(&zio->io_parent_list);
578 list_destroy(&zio->io_child_list);
579 mutex_destroy(&zio->io_lock);
580 cv_destroy(&zio->io_cv);
581 kmem_cache_free(zio_cache, zio);
582 }
583
584 zio_t *
585 zio_null(zio_t *pio, spa_t *spa, vdev_t *vd, zio_done_func_t *done,
586 void *private, enum zio_flag flags)
587 {
588 zio_t *zio;
589
590 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private,
591 ZIO_TYPE_NULL, ZIO_PRIORITY_NOW, flags, vd, 0, NULL,
592 ZIO_STAGE_OPEN, ZIO_INTERLOCK_PIPELINE);
593
594 return (zio);
595 }
596
597 zio_t *
598 zio_root(spa_t *spa, zio_done_func_t *done, void *private, enum zio_flag flags)
599 {
600 return (zio_null(NULL, spa, NULL, done, private, flags));
601 }
602
603 zio_t *
604 zio_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
605 void *data, uint64_t size, zio_done_func_t *done, void *private,
606 zio_priority_t priority, enum zio_flag flags, const zbookmark_t *zb)
607 {
608 zio_t *zio;
609
610 zio = zio_create(pio, spa, BP_PHYSICAL_BIRTH(bp), bp,
611 data, size, done, private,
612 ZIO_TYPE_READ, priority, flags, NULL, 0, zb,
613 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ?
614 ZIO_DDT_CHILD_READ_PIPELINE : ZIO_READ_PIPELINE);
615
616 return (zio);
617 }
618
619 zio_t *
620 zio_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
621 void *data, uint64_t size, const zio_prop_t *zp,
622 zio_done_func_t *ready, zio_done_func_t *physdone, zio_done_func_t *done,
623 void *private,
624 zio_priority_t priority, enum zio_flag flags, const zbookmark_t *zb)
625 {
626 zio_t *zio;
627
628 ASSERT(zp->zp_checksum >= ZIO_CHECKSUM_OFF &&
629 zp->zp_checksum < ZIO_CHECKSUM_FUNCTIONS &&
630 zp->zp_compress >= ZIO_COMPRESS_OFF &&
631 zp->zp_compress < ZIO_COMPRESS_FUNCTIONS &&
632 DMU_OT_IS_VALID(zp->zp_type) &&
633 zp->zp_level < 32 &&
634 zp->zp_copies > 0 &&
635 zp->zp_copies <= spa_max_replication(spa));
636
637 zio = zio_create(pio, spa, txg, bp, data, size, done, private,
638 ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb,
639 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ?
640 ZIO_DDT_CHILD_WRITE_PIPELINE : ZIO_WRITE_PIPELINE);
641
642 zio->io_ready = ready;
643 zio->io_physdone = physdone;
644 zio->io_prop = *zp;
645
646 return (zio);
647 }
648
649 zio_t *
650 zio_rewrite(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, void *data,
651 uint64_t size, zio_done_func_t *done, void *private,
652 zio_priority_t priority, enum zio_flag flags, zbookmark_t *zb)
653 {
654 zio_t *zio;
655
656 zio = zio_create(pio, spa, txg, bp, data, size, done, private,
657 ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb,
658 ZIO_STAGE_OPEN, ZIO_REWRITE_PIPELINE);
659
660 return (zio);
661 }
662
663 void
664 zio_write_override(zio_t *zio, blkptr_t *bp, int copies, boolean_t nopwrite)
665 {
666 ASSERT(zio->io_type == ZIO_TYPE_WRITE);
667 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
668 ASSERT(zio->io_stage == ZIO_STAGE_OPEN);
669 ASSERT(zio->io_txg == spa_syncing_txg(zio->io_spa));
670
671 /*
672 * We must reset the io_prop to match the values that existed
673 * when the bp was first written by dmu_sync() keeping in mind
674 * that nopwrite and dedup are mutually exclusive.
675 */
676 zio->io_prop.zp_dedup = nopwrite ? B_FALSE : zio->io_prop.zp_dedup;
677 zio->io_prop.zp_nopwrite = nopwrite;
678 zio->io_prop.zp_copies = copies;
679 zio->io_bp_override = bp;
680 }
681
682 void
683 zio_free(spa_t *spa, uint64_t txg, const blkptr_t *bp)
684 {
685 metaslab_check_free(spa, bp);
686
687 /*
688 * Frees that are for the currently-syncing txg, are not going to be
689 * deferred, and which will not need to do a read (i.e. not GANG or
690 * DEDUP), can be processed immediately. Otherwise, put them on the
691 * in-memory list for later processing.
692 */
693 if (BP_IS_GANG(bp) || BP_GET_DEDUP(bp) ||
694 txg != spa->spa_syncing_txg ||
695 spa_sync_pass(spa) >= zfs_sync_pass_deferred_free) {
696 bplist_append(&spa->spa_free_bplist[txg & TXG_MASK], bp);
697 } else {
698 VERIFY0(zio_wait(zio_free_sync(NULL, spa, txg, bp, 0)));
699 }
700 }
701
702 zio_t *
703 zio_free_sync(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
704 enum zio_flag flags)
705 {
706 zio_t *zio;
707 enum zio_stage stage = ZIO_FREE_PIPELINE;
708
709 dprintf_bp(bp, "freeing in txg %llu, pass %u",
710 (longlong_t)txg, spa->spa_sync_pass);
711
712 ASSERT(!BP_IS_HOLE(bp));
713 ASSERT(spa_syncing_txg(spa) == txg);
714 ASSERT(spa_sync_pass(spa) < zfs_sync_pass_deferred_free);
715
716 metaslab_check_free(spa, bp);
717 arc_freed(spa, bp);
718
719 /*
720 * GANG and DEDUP blocks can induce a read (for the gang block header,
721 * or the DDT), so issue them asynchronously so that this thread is
722 * not tied up.
723 */
724 if (BP_IS_GANG(bp) || BP_GET_DEDUP(bp))
725 stage |= ZIO_STAGE_ISSUE_ASYNC;
726
727 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp),
728 NULL, NULL, ZIO_TYPE_FREE, ZIO_PRIORITY_NOW, flags,
729 NULL, 0, NULL, ZIO_STAGE_OPEN, stage);
730
731
732 return (zio);
733 }
734
735 zio_t *
736 zio_claim(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
737 zio_done_func_t *done, void *private, enum zio_flag flags)
738 {
739 zio_t *zio;
740
741 /*
742 * A claim is an allocation of a specific block. Claims are needed
743 * to support immediate writes in the intent log. The issue is that
744 * immediate writes contain committed data, but in a txg that was
745 * *not* committed. Upon opening the pool after an unclean shutdown,
746 * the intent log claims all blocks that contain immediate write data
747 * so that the SPA knows they're in use.
748 *
749 * All claims *must* be resolved in the first txg -- before the SPA
750 * starts allocating blocks -- so that nothing is allocated twice.
751 * If txg == 0 we just verify that the block is claimable.
752 */
753 ASSERT3U(spa->spa_uberblock.ub_rootbp.blk_birth, <, spa_first_txg(spa));
754 ASSERT(txg == spa_first_txg(spa) || txg == 0);
755 ASSERT(!BP_GET_DEDUP(bp) || !spa_writeable(spa)); /* zdb(1M) */
756
757 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp),
758 done, private, ZIO_TYPE_CLAIM, ZIO_PRIORITY_NOW, flags,
759 NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_CLAIM_PIPELINE);
760
761 return (zio);
762 }
763
764 zio_t *
765 zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd,
766 zio_done_func_t *done, void *private, enum zio_flag flags)
767 {
768 zio_t *zio;
769 int c;
770
771 if (vd->vdev_children == 0) {
772 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private,
773 ZIO_TYPE_IOCTL, ZIO_PRIORITY_NOW, flags, vd, 0, NULL,
774 ZIO_STAGE_OPEN, ZIO_IOCTL_PIPELINE);
775
776 zio->io_cmd = cmd;
777 } else {
778 zio = zio_null(pio, spa, NULL, NULL, NULL, flags);
779
780 for (c = 0; c < vd->vdev_children; c++)
781 zio_nowait(zio_ioctl(zio, spa, vd->vdev_child[c], cmd,
782 done, private, flags));
783 }
784
785 return (zio);
786 }
787
788 zio_t *
789 zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size,
790 void *data, int checksum, zio_done_func_t *done, void *private,
791 zio_priority_t priority, enum zio_flag flags, boolean_t labels)
792 {
793 zio_t *zio;
794
795 ASSERT(vd->vdev_children == 0);
796 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE ||
797 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE);
798 ASSERT3U(offset + size, <=, vd->vdev_psize);
799
800 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private,
801 ZIO_TYPE_READ, priority, flags, vd, offset, NULL,
802 ZIO_STAGE_OPEN, ZIO_READ_PHYS_PIPELINE);
803
804 zio->io_prop.zp_checksum = checksum;
805
806 return (zio);
807 }
808
809 zio_t *
810 zio_write_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size,
811 void *data, int checksum, zio_done_func_t *done, void *private,
812 zio_priority_t priority, enum zio_flag flags, boolean_t labels)
813 {
814 zio_t *zio;
815
816 ASSERT(vd->vdev_children == 0);
817 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE ||
818 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE);
819 ASSERT3U(offset + size, <=, vd->vdev_psize);
820
821 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private,
822 ZIO_TYPE_WRITE, priority, flags, vd, offset, NULL,
823 ZIO_STAGE_OPEN, ZIO_WRITE_PHYS_PIPELINE);
824
825 zio->io_prop.zp_checksum = checksum;
826
827 if (zio_checksum_table[checksum].ci_eck) {
828 /*
829 * zec checksums are necessarily destructive -- they modify
830 * the end of the write buffer to hold the verifier/checksum.
831 * Therefore, we must make a local copy in case the data is
832 * being written to multiple places in parallel.
833 */
834 void *wbuf = zio_buf_alloc(size);
835 bcopy(data, wbuf, size);
836 zio_push_transform(zio, wbuf, size, size, NULL);
837 }
838
839 return (zio);
840 }
841
842 /*
843 * Create a child I/O to do some work for us.
844 */
845 zio_t *
846 zio_vdev_child_io(zio_t *pio, blkptr_t *bp, vdev_t *vd, uint64_t offset,
847 void *data, uint64_t size, int type, zio_priority_t priority,
848 enum zio_flag flags, zio_done_func_t *done, void *private)
849 {
850 enum zio_stage pipeline = ZIO_VDEV_CHILD_PIPELINE;
851 zio_t *zio;
852
853 ASSERT(vd->vdev_parent ==
854 (pio->io_vd ? pio->io_vd : pio->io_spa->spa_root_vdev));
855
856 if (type == ZIO_TYPE_READ && bp != NULL) {
857 /*
858 * If we have the bp, then the child should perform the
859 * checksum and the parent need not. This pushes error
860 * detection as close to the leaves as possible and
861 * eliminates redundant checksums in the interior nodes.
862 */
863 pipeline |= ZIO_STAGE_CHECKSUM_VERIFY;
864 pio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY;
865 }
866
867 if (vd->vdev_children == 0)
868 offset += VDEV_LABEL_START_SIZE;
869
870 flags |= ZIO_VDEV_CHILD_FLAGS(pio) | ZIO_FLAG_DONT_PROPAGATE;
871
872 /*
873 * If we've decided to do a repair, the write is not speculative --
874 * even if the original read was.
875 */
876 if (flags & ZIO_FLAG_IO_REPAIR)
877 flags &= ~ZIO_FLAG_SPECULATIVE;
878
879 zio = zio_create(pio, pio->io_spa, pio->io_txg, bp, data, size,
880 done, private, type, priority, flags, vd, offset, &pio->io_bookmark,
881 ZIO_STAGE_VDEV_IO_START >> 1, pipeline);
882
883 zio->io_physdone = pio->io_physdone;
884 if (vd->vdev_ops->vdev_op_leaf && zio->io_logical != NULL)
885 zio->io_logical->io_phys_children++;
886
887 return (zio);
888 }
889
890 zio_t *
891 zio_vdev_delegated_io(vdev_t *vd, uint64_t offset, void *data, uint64_t size,
892 int type, zio_priority_t priority, enum zio_flag flags,
893 zio_done_func_t *done, void *private)
894 {
895 zio_t *zio;
896
897 ASSERT(vd->vdev_ops->vdev_op_leaf);
898
899 zio = zio_create(NULL, vd->vdev_spa, 0, NULL,
900 data, size, done, private, type, priority,
901 flags | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_RETRY | ZIO_FLAG_DELEGATED,
902 vd, offset, NULL,
903 ZIO_STAGE_VDEV_IO_START >> 1, ZIO_VDEV_CHILD_PIPELINE);
904
905 return (zio);
906 }
907
908 void
909 zio_flush(zio_t *zio, vdev_t *vd)
910 {
911 zio_nowait(zio_ioctl(zio, zio->io_spa, vd, DKIOCFLUSHWRITECACHE,
912 NULL, NULL,
913 ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY));
914 }
915
916 void
917 zio_shrink(zio_t *zio, uint64_t size)
918 {
919 ASSERT(zio->io_executor == NULL);
920 ASSERT(zio->io_orig_size == zio->io_size);
921 ASSERT(size <= zio->io_size);
922
923 /*
924 * We don't shrink for raidz because of problems with the
925 * reconstruction when reading back less than the block size.
926 * Note, BP_IS_RAIDZ() assumes no compression.
927 */
928 ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF);
929 if (!BP_IS_RAIDZ(zio->io_bp))
930 zio->io_orig_size = zio->io_size = size;
931 }
932
933 /*
934 * ==========================================================================
935 * Prepare to read and write logical blocks
936 * ==========================================================================
937 */
938
939 static int
940 zio_read_bp_init(zio_t *zio)
941 {
942 blkptr_t *bp = zio->io_bp;
943
944 if (BP_GET_COMPRESS(bp) != ZIO_COMPRESS_OFF &&
945 zio->io_child_type == ZIO_CHILD_LOGICAL &&
946 !(zio->io_flags & ZIO_FLAG_RAW)) {
947 uint64_t psize = BP_GET_PSIZE(bp);
948 void *cbuf = zio_buf_alloc(psize);
949
950 zio_push_transform(zio, cbuf, psize, psize, zio_decompress);
951 }
952
953 if (!DMU_OT_IS_METADATA(BP_GET_TYPE(bp)) && BP_GET_LEVEL(bp) == 0)
954 zio->io_flags |= ZIO_FLAG_DONT_CACHE;
955
956 if (BP_GET_TYPE(bp) == DMU_OT_DDT_ZAP)
957 zio->io_flags |= ZIO_FLAG_DONT_CACHE;
958
959 if (BP_GET_DEDUP(bp) && zio->io_child_type == ZIO_CHILD_LOGICAL)
960 zio->io_pipeline = ZIO_DDT_READ_PIPELINE;
961
962 return (ZIO_PIPELINE_CONTINUE);
963 }
964
965 static int
966 zio_write_bp_init(zio_t *zio)
967 {
968 spa_t *spa = zio->io_spa;
969 zio_prop_t *zp = &zio->io_prop;
970 enum zio_compress compress = zp->zp_compress;
971 blkptr_t *bp = zio->io_bp;
972 uint64_t lsize = zio->io_size;
973 uint64_t psize = lsize;
974 int pass = 1;
975
976 /*
977 * If our children haven't all reached the ready stage,
978 * wait for them and then repeat this pipeline stage.
979 */
980 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) ||
981 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_READY))
982 return (ZIO_PIPELINE_STOP);
983
984 if (!IO_IS_ALLOCATING(zio))
985 return (ZIO_PIPELINE_CONTINUE);
986
987 ASSERT(zio->io_child_type != ZIO_CHILD_DDT);
988
989 if (zio->io_bp_override) {
990 ASSERT(bp->blk_birth != zio->io_txg);
991 ASSERT(BP_GET_DEDUP(zio->io_bp_override) == 0);
992
993 *bp = *zio->io_bp_override;
994 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
995
996 /*
997 * If we've been overridden and nopwrite is set then
998 * set the flag accordingly to indicate that a nopwrite
999 * has already occurred.
1000 */
1001 if (!BP_IS_HOLE(bp) && zp->zp_nopwrite) {
1002 ASSERT(!zp->zp_dedup);
1003 zio->io_flags |= ZIO_FLAG_NOPWRITE;
1004 return (ZIO_PIPELINE_CONTINUE);
1005 }
1006
1007 ASSERT(!zp->zp_nopwrite);
1008
1009 if (BP_IS_HOLE(bp) || !zp->zp_dedup)
1010 return (ZIO_PIPELINE_CONTINUE);
1011
1012 ASSERT(zio_checksum_table[zp->zp_checksum].ci_dedup ||
1013 zp->zp_dedup_verify);
1014
1015 if (BP_GET_CHECKSUM(bp) == zp->zp_checksum) {
1016 BP_SET_DEDUP(bp, 1);
1017 zio->io_pipeline |= ZIO_STAGE_DDT_WRITE;
1018 return (ZIO_PIPELINE_CONTINUE);
1019 }
1020 zio->io_bp_override = NULL;
1021 BP_ZERO(bp);
1022 }
1023
1024 if (bp->blk_birth == zio->io_txg) {
1025 /*
1026 * We're rewriting an existing block, which means we're
1027 * working on behalf of spa_sync(). For spa_sync() to
1028 * converge, it must eventually be the case that we don't
1029 * have to allocate new blocks. But compression changes
1030 * the blocksize, which forces a reallocate, and makes
1031 * convergence take longer. Therefore, after the first
1032 * few passes, stop compressing to ensure convergence.
1033 */
1034 pass = spa_sync_pass(spa);
1035
1036 ASSERT(zio->io_txg == spa_syncing_txg(spa));
1037 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1038 ASSERT(!BP_GET_DEDUP(bp));
1039
1040 if (pass >= zfs_sync_pass_dont_compress)
1041 compress = ZIO_COMPRESS_OFF;
1042
1043 /* Make sure someone doesn't change their mind on overwrites */
1044 ASSERT(MIN(zp->zp_copies + BP_IS_GANG(bp),
1045 spa_max_replication(spa)) == BP_GET_NDVAS(bp));
1046 }
1047
1048 if (compress != ZIO_COMPRESS_OFF) {
1049 void *cbuf = zio_buf_alloc(lsize);
1050 psize = zio_compress_data(compress, zio->io_data, cbuf, lsize);
1051 if (psize == 0 || psize == lsize) {
1052 compress = ZIO_COMPRESS_OFF;
1053 zio_buf_free(cbuf, lsize);
1054 } else {
1055 ASSERT(psize < lsize);
1056 zio_push_transform(zio, cbuf, psize, lsize, NULL);
1057 }
1058 }
1059
1060 /*
1061 * The final pass of spa_sync() must be all rewrites, but the first
1062 * few passes offer a trade-off: allocating blocks defers convergence,
1063 * but newly allocated blocks are sequential, so they can be written
1064 * to disk faster. Therefore, we allow the first few passes of
1065 * spa_sync() to allocate new blocks, but force rewrites after that.
1066 * There should only be a handful of blocks after pass 1 in any case.
1067 */
1068 if (bp->blk_birth == zio->io_txg && BP_GET_PSIZE(bp) == psize &&
1069 pass >= zfs_sync_pass_rewrite) {
1070 ASSERT(psize != 0);
1071 enum zio_stage gang_stages = zio->io_pipeline & ZIO_GANG_STAGES;
1072 zio->io_pipeline = ZIO_REWRITE_PIPELINE | gang_stages;
1073 zio->io_flags |= ZIO_FLAG_IO_REWRITE;
1074 } else {
1075 BP_ZERO(bp);
1076 zio->io_pipeline = ZIO_WRITE_PIPELINE;
1077 }
1078
1079 if (psize == 0) {
1080 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1081 } else {
1082 ASSERT(zp->zp_checksum != ZIO_CHECKSUM_GANG_HEADER);
1083 BP_SET_LSIZE(bp, lsize);
1084 BP_SET_PSIZE(bp, psize);
1085 BP_SET_COMPRESS(bp, compress);
1086 BP_SET_CHECKSUM(bp, zp->zp_checksum);
1087 BP_SET_TYPE(bp, zp->zp_type);
1088 BP_SET_LEVEL(bp, zp->zp_level);
1089 BP_SET_DEDUP(bp, zp->zp_dedup);
1090 BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER);
1091 if (zp->zp_dedup) {
1092 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1093 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE));
1094 zio->io_pipeline = ZIO_DDT_WRITE_PIPELINE;
1095 }
1096 if (zp->zp_nopwrite) {
1097 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1098 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE));
1099 zio->io_pipeline |= ZIO_STAGE_NOP_WRITE;
1100 }
1101 }
1102
1103 return (ZIO_PIPELINE_CONTINUE);
1104 }
1105
1106 static int
1107 zio_free_bp_init(zio_t *zio)
1108 {
1109 blkptr_t *bp = zio->io_bp;
1110
1111 if (zio->io_child_type == ZIO_CHILD_LOGICAL) {
1112 if (BP_GET_DEDUP(bp))
1113 zio->io_pipeline = ZIO_DDT_FREE_PIPELINE;
1114 }
1115
1116 return (ZIO_PIPELINE_CONTINUE);
1117 }
1118
1119 /*
1120 * ==========================================================================
1121 * Execute the I/O pipeline
1122 * ==========================================================================
1123 */
1124
1125 static void
1126 zio_taskq_dispatch(zio_t *zio, zio_taskq_type_t q, boolean_t cutinline)
1127 {
1128 spa_t *spa = zio->io_spa;
1129 zio_type_t t = zio->io_type;
1130 int flags = (cutinline ? TQ_FRONT : 0);
1131
1132 /*
1133 * If we're a config writer or a probe, the normal issue and
1134 * interrupt threads may all be blocked waiting for the config lock.
1135 * In this case, select the otherwise-unused taskq for ZIO_TYPE_NULL.
1136 */
1137 if (zio->io_flags & (ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_PROBE))
1138 t = ZIO_TYPE_NULL;
1139
1140 /*
1141 * A similar issue exists for the L2ARC write thread until L2ARC 2.0.
1142 */
1143 if (t == ZIO_TYPE_WRITE && zio->io_vd && zio->io_vd->vdev_aux)
1144 t = ZIO_TYPE_NULL;
1145
1146 /*
1147 * If this is a high priority I/O, then use the high priority taskq if
1148 * available.
1149 */
1150 if (zio->io_priority == ZIO_PRIORITY_NOW &&
1151 spa->spa_zio_taskq[t][q + 1].stqs_count != 0)
1152 q++;
1153
1154 ASSERT3U(q, <, ZIO_TASKQ_TYPES);
1155
1156 /*
1157 * NB: We are assuming that the zio can only be dispatched
1158 * to a single taskq at a time. It would be a grievous error
1159 * to dispatch the zio to another taskq at the same time.
1160 */
1161 ASSERT(zio->io_tqent.tqent_next == NULL);
1162 spa_taskq_dispatch_ent(spa, t, q, (task_func_t *)zio_execute, zio,
1163 flags, &zio->io_tqent);
1164 }
1165
1166 static boolean_t
1167 zio_taskq_member(zio_t *zio, zio_taskq_type_t q)
1168 {
1169 kthread_t *executor = zio->io_executor;
1170 spa_t *spa = zio->io_spa;
1171
1172 for (zio_type_t t = 0; t < ZIO_TYPES; t++) {
1173 spa_taskqs_t *tqs = &spa->spa_zio_taskq[t][q];
1174 uint_t i;
1175 for (i = 0; i < tqs->stqs_count; i++) {
1176 if (taskq_member(tqs->stqs_taskq[i], executor))
1177 return (B_TRUE);
1178 }
1179 }
1180
1181 return (B_FALSE);
1182 }
1183
1184 static int
1185 zio_issue_async(zio_t *zio)
1186 {
1187 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE);
1188
1189 return (ZIO_PIPELINE_STOP);
1190 }
1191
1192 void
1193 zio_interrupt(zio_t *zio)
1194 {
1195 zio_taskq_dispatch(zio, ZIO_TASKQ_INTERRUPT, B_FALSE);
1196 }
1197
1198 /*
1199 * Execute the I/O pipeline until one of the following occurs:
1200 *
1201 * (1) the I/O completes
1202 * (2) the pipeline stalls waiting for dependent child I/Os
1203 * (3) the I/O issues, so we're waiting for an I/O completion interrupt
1204 * (4) the I/O is delegated by vdev-level caching or aggregation
1205 * (5) the I/O is deferred due to vdev-level queueing
1206 * (6) the I/O is handed off to another thread.
1207 *
1208 * In all cases, the pipeline stops whenever there's no CPU work; it never
1209 * burns a thread in cv_wait().
1210 *
1211 * There's no locking on io_stage because there's no legitimate way
1212 * for multiple threads to be attempting to process the same I/O.
1213 */
1214 static zio_pipe_stage_t *zio_pipeline[];
1215
1216 void
1217 zio_execute(zio_t *zio)
1218 {
1219 zio->io_executor = curthread;
1220
1221 while (zio->io_stage < ZIO_STAGE_DONE) {
1222 enum zio_stage pipeline = zio->io_pipeline;
1223 enum zio_stage stage = zio->io_stage;
1224 int rv;
1225
1226 ASSERT(!MUTEX_HELD(&zio->io_lock));
1227 ASSERT(ISP2(stage));
1228 ASSERT(zio->io_stall == NULL);
1229
1230 do {
1231 stage <<= 1;
1232 } while ((stage & pipeline) == 0);
1233
1234 ASSERT(stage <= ZIO_STAGE_DONE);
1235
1236 /*
1237 * If we are in interrupt context and this pipeline stage
1238 * will grab a config lock that is held across I/O,
1239 * or may wait for an I/O that needs an interrupt thread
1240 * to complete, issue async to avoid deadlock.
1241 *
1242 * For VDEV_IO_START, we cut in line so that the io will
1243 * be sent to disk promptly.
1244 */
1245 if ((stage & ZIO_BLOCKING_STAGES) && zio->io_vd == NULL &&
1246 zio_taskq_member(zio, ZIO_TASKQ_INTERRUPT)) {
1247 boolean_t cut = (stage == ZIO_STAGE_VDEV_IO_START) ?
1248 zio_requeue_io_start_cut_in_line : B_FALSE;
1249 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, cut);
1250 return;
1251 }
1252
1253 zio->io_stage = stage;
1254 rv = zio_pipeline[highbit(stage) - 1](zio);
1255
1256 if (rv == ZIO_PIPELINE_STOP)
1257 return;
1258
1259 ASSERT(rv == ZIO_PIPELINE_CONTINUE);
1260 }
1261 }
1262
1263 /*
1264 * ==========================================================================
1265 * Initiate I/O, either sync or async
1266 * ==========================================================================
1267 */
1268 int
1269 zio_wait(zio_t *zio)
1270 {
1271 int error;
1272
1273 ASSERT(zio->io_stage == ZIO_STAGE_OPEN);
1274 ASSERT(zio->io_executor == NULL);
1275
1276 zio->io_waiter = curthread;
1277
1278 zio_execute(zio);
1279
1280 mutex_enter(&zio->io_lock);
1281 while (zio->io_executor != NULL)
1282 cv_wait(&zio->io_cv, &zio->io_lock);
1283 mutex_exit(&zio->io_lock);
1284
1285 error = zio->io_error;
1286 zio_destroy(zio);
1287
1288 return (error);
1289 }
1290
1291 void
1292 zio_nowait(zio_t *zio)
1293 {
1294 ASSERT(zio->io_executor == NULL);
1295
1296 if (zio->io_child_type == ZIO_CHILD_LOGICAL &&
1297 zio_unique_parent(zio) == NULL) {
1298 /*
1299 * This is a logical async I/O with no parent to wait for it.
1300 * We add it to the spa_async_root_zio "Godfather" I/O which
1301 * will ensure they complete prior to unloading the pool.
1302 */
1303 spa_t *spa = zio->io_spa;
1304
1305 zio_add_child(spa->spa_async_zio_root, zio);
1306 }
1307
1308 zio_execute(zio);
1309 }
1310
1311 /*
1312 * ==========================================================================
1313 * Reexecute or suspend/resume failed I/O
1314 * ==========================================================================
1315 */
1316
1317 static void
1318 zio_reexecute(zio_t *pio)
1319 {
1320 zio_t *cio, *cio_next;
1321
1322 ASSERT(pio->io_child_type == ZIO_CHILD_LOGICAL);
1323 ASSERT(pio->io_orig_stage == ZIO_STAGE_OPEN);
1324 ASSERT(pio->io_gang_leader == NULL);
1325 ASSERT(pio->io_gang_tree == NULL);
1326
1327 pio->io_flags = pio->io_orig_flags;
1328 pio->io_stage = pio->io_orig_stage;
1329 pio->io_pipeline = pio->io_orig_pipeline;
1330 pio->io_reexecute = 0;
1331 pio->io_flags |= ZIO_FLAG_REEXECUTED;
1332 pio->io_error = 0;
1333 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
1334 pio->io_state[w] = 0;
1335 for (int c = 0; c < ZIO_CHILD_TYPES; c++)
1336 pio->io_child_error[c] = 0;
1337
1338 if (IO_IS_ALLOCATING(pio))
1339 BP_ZERO(pio->io_bp);
1340
1341 /*
1342 * As we reexecute pio's children, new children could be created.
1343 * New children go to the head of pio's io_child_list, however,
1344 * so we will (correctly) not reexecute them. The key is that
1345 * the remainder of pio's io_child_list, from 'cio_next' onward,
1346 * cannot be affected by any side effects of reexecuting 'cio'.
1347 */
1348 for (cio = zio_walk_children(pio); cio != NULL; cio = cio_next) {
1349 cio_next = zio_walk_children(pio);
1350 mutex_enter(&pio->io_lock);
1351 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
1352 pio->io_children[cio->io_child_type][w]++;
1353 mutex_exit(&pio->io_lock);
1354 zio_reexecute(cio);
1355 }
1356
1357 /*
1358 * Now that all children have been reexecuted, execute the parent.
1359 * We don't reexecute "The Godfather" I/O here as it's the
1360 * responsibility of the caller to wait on him.
1361 */
1362 if (!(pio->io_flags & ZIO_FLAG_GODFATHER))
1363 zio_execute(pio);
1364 }
1365
1366 void
1367 zio_suspend(spa_t *spa, zio_t *zio)
1368 {
1369 if (spa_get_failmode(spa) == ZIO_FAILURE_MODE_PANIC)
1370 fm_panic("Pool '%s' has encountered an uncorrectable I/O "
1371 "failure and the failure mode property for this pool "
1372 "is set to panic.", spa_name(spa));
1373
1374 zfs_ereport_post(FM_EREPORT_ZFS_IO_FAILURE, spa, NULL, NULL, 0, 0);
1375
1376 mutex_enter(&spa->spa_suspend_lock);
1377
1378 if (spa->spa_suspend_zio_root == NULL)
1379 spa->spa_suspend_zio_root = zio_root(spa, NULL, NULL,
1380 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE |
1381 ZIO_FLAG_GODFATHER);
1382
1383 spa->spa_suspended = B_TRUE;
1384
1385 if (zio != NULL) {
1386 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER));
1387 ASSERT(zio != spa->spa_suspend_zio_root);
1388 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1389 ASSERT(zio_unique_parent(zio) == NULL);
1390 ASSERT(zio->io_stage == ZIO_STAGE_DONE);
1391 zio_add_child(spa->spa_suspend_zio_root, zio);
1392 }
1393
1394 mutex_exit(&spa->spa_suspend_lock);
1395 }
1396
1397 int
1398 zio_resume(spa_t *spa)
1399 {
1400 zio_t *pio;
1401
1402 /*
1403 * Reexecute all previously suspended i/o.
1404 */
1405 mutex_enter(&spa->spa_suspend_lock);
1406 spa->spa_suspended = B_FALSE;
1407 cv_broadcast(&spa->spa_suspend_cv);
1408 pio = spa->spa_suspend_zio_root;
1409 spa->spa_suspend_zio_root = NULL;
1410 mutex_exit(&spa->spa_suspend_lock);
1411
1412 if (pio == NULL)
1413 return (0);
1414
1415 zio_reexecute(pio);
1416 return (zio_wait(pio));
1417 }
1418
1419 void
1420 zio_resume_wait(spa_t *spa)
1421 {
1422 mutex_enter(&spa->spa_suspend_lock);
1423 while (spa_suspended(spa))
1424 cv_wait(&spa->spa_suspend_cv, &spa->spa_suspend_lock);
1425 mutex_exit(&spa->spa_suspend_lock);
1426 }
1427
1428 /*
1429 * ==========================================================================
1430 * Gang blocks.
1431 *
1432 * A gang block is a collection of small blocks that looks to the DMU
1433 * like one large block. When zio_dva_allocate() cannot find a block
1434 * of the requested size, due to either severe fragmentation or the pool
1435 * being nearly full, it calls zio_write_gang_block() to construct the
1436 * block from smaller fragments.
1437 *
1438 * A gang block consists of a gang header (zio_gbh_phys_t) and up to
1439 * three (SPA_GBH_NBLKPTRS) gang members. The gang header is just like
1440 * an indirect block: it's an array of block pointers. It consumes
1441 * only one sector and hence is allocatable regardless of fragmentation.
1442 * The gang header's bps point to its gang members, which hold the data.
1443 *
1444 * Gang blocks are self-checksumming, using the bp's <vdev, offset, txg>
1445 * as the verifier to ensure uniqueness of the SHA256 checksum.
1446 * Critically, the gang block bp's blk_cksum is the checksum of the data,
1447 * not the gang header. This ensures that data block signatures (needed for
1448 * deduplication) are independent of how the block is physically stored.
1449 *
1450 * Gang blocks can be nested: a gang member may itself be a gang block.
1451 * Thus every gang block is a tree in which root and all interior nodes are
1452 * gang headers, and the leaves are normal blocks that contain user data.
1453 * The root of the gang tree is called the gang leader.
1454 *
1455 * To perform any operation (read, rewrite, free, claim) on a gang block,
1456 * zio_gang_assemble() first assembles the gang tree (minus data leaves)
1457 * in the io_gang_tree field of the original logical i/o by recursively
1458 * reading the gang leader and all gang headers below it. This yields
1459 * an in-core tree containing the contents of every gang header and the
1460 * bps for every constituent of the gang block.
1461 *
1462 * With the gang tree now assembled, zio_gang_issue() just walks the gang tree
1463 * and invokes a callback on each bp. To free a gang block, zio_gang_issue()
1464 * calls zio_free_gang() -- a trivial wrapper around zio_free() -- for each bp.
1465 * zio_claim_gang() provides a similarly trivial wrapper for zio_claim().
1466 * zio_read_gang() is a wrapper around zio_read() that omits reading gang
1467 * headers, since we already have those in io_gang_tree. zio_rewrite_gang()
1468 * performs a zio_rewrite() of the data or, for gang headers, a zio_rewrite()
1469 * of the gang header plus zio_checksum_compute() of the data to update the
1470 * gang header's blk_cksum as described above.
1471 *
1472 * The two-phase assemble/issue model solves the problem of partial failure --
1473 * what if you'd freed part of a gang block but then couldn't read the
1474 * gang header for another part? Assembling the entire gang tree first
1475 * ensures that all the necessary gang header I/O has succeeded before
1476 * starting the actual work of free, claim, or write. Once the gang tree
1477 * is assembled, free and claim are in-memory operations that cannot fail.
1478 *
1479 * In the event that a gang write fails, zio_dva_unallocate() walks the
1480 * gang tree to immediately free (i.e. insert back into the space map)
1481 * everything we've allocated. This ensures that we don't get ENOSPC
1482 * errors during repeated suspend/resume cycles due to a flaky device.
1483 *
1484 * Gang rewrites only happen during sync-to-convergence. If we can't assemble
1485 * the gang tree, we won't modify the block, so we can safely defer the free
1486 * (knowing that the block is still intact). If we *can* assemble the gang
1487 * tree, then even if some of the rewrites fail, zio_dva_unallocate() will free
1488 * each constituent bp and we can allocate a new block on the next sync pass.
1489 *
1490 * In all cases, the gang tree allows complete recovery from partial failure.
1491 * ==========================================================================
1492 */
1493
1494 static zio_t *
1495 zio_read_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1496 {
1497 if (gn != NULL)
1498 return (pio);
1499
1500 return (zio_read(pio, pio->io_spa, bp, data, BP_GET_PSIZE(bp),
1501 NULL, NULL, pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio),
1502 &pio->io_bookmark));
1503 }
1504
1505 zio_t *
1506 zio_rewrite_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1507 {
1508 zio_t *zio;
1509
1510 if (gn != NULL) {
1511 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp,
1512 gn->gn_gbh, SPA_GANGBLOCKSIZE, NULL, NULL, pio->io_priority,
1513 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
1514 /*
1515 * As we rewrite each gang header, the pipeline will compute
1516 * a new gang block header checksum for it; but no one will
1517 * compute a new data checksum, so we do that here. The one
1518 * exception is the gang leader: the pipeline already computed
1519 * its data checksum because that stage precedes gang assembly.
1520 * (Presently, nothing actually uses interior data checksums;
1521 * this is just good hygiene.)
1522 */
1523 if (gn != pio->io_gang_leader->io_gang_tree) {
1524 zio_checksum_compute(zio, BP_GET_CHECKSUM(bp),
1525 data, BP_GET_PSIZE(bp));
1526 }
1527 /*
1528 * If we are here to damage data for testing purposes,
1529 * leave the GBH alone so that we can detect the damage.
1530 */
1531 if (pio->io_gang_leader->io_flags & ZIO_FLAG_INDUCE_DAMAGE)
1532 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES;
1533 } else {
1534 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp,
1535 data, BP_GET_PSIZE(bp), NULL, NULL, pio->io_priority,
1536 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
1537 }
1538
1539 return (zio);
1540 }
1541
1542 /* ARGSUSED */
1543 zio_t *
1544 zio_free_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1545 {
1546 return (zio_free_sync(pio, pio->io_spa, pio->io_txg, bp,
1547 ZIO_GANG_CHILD_FLAGS(pio)));
1548 }
1549
1550 /* ARGSUSED */
1551 zio_t *
1552 zio_claim_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1553 {
1554 return (zio_claim(pio, pio->io_spa, pio->io_txg, bp,
1555 NULL, NULL, ZIO_GANG_CHILD_FLAGS(pio)));
1556 }
1557
1558 static zio_gang_issue_func_t *zio_gang_issue_func[ZIO_TYPES] = {
1559 NULL,
1560 zio_read_gang,
1561 zio_rewrite_gang,
1562 zio_free_gang,
1563 zio_claim_gang,
1564 NULL
1565 };
1566
1567 static void zio_gang_tree_assemble_done(zio_t *zio);
1568
1569 static zio_gang_node_t *
1570 zio_gang_node_alloc(zio_gang_node_t **gnpp)
1571 {
1572 zio_gang_node_t *gn;
1573
1574 ASSERT(*gnpp == NULL);
1575
1576 gn = kmem_zalloc(sizeof (*gn), KM_SLEEP);
1577 gn->gn_gbh = zio_buf_alloc(SPA_GANGBLOCKSIZE);
1578 *gnpp = gn;
1579
1580 return (gn);
1581 }
1582
1583 static void
1584 zio_gang_node_free(zio_gang_node_t **gnpp)
1585 {
1586 zio_gang_node_t *gn = *gnpp;
1587
1588 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++)
1589 ASSERT(gn->gn_child[g] == NULL);
1590
1591 zio_buf_free(gn->gn_gbh, SPA_GANGBLOCKSIZE);
1592 kmem_free(gn, sizeof (*gn));
1593 *gnpp = NULL;
1594 }
1595
1596 static void
1597 zio_gang_tree_free(zio_gang_node_t **gnpp)
1598 {
1599 zio_gang_node_t *gn = *gnpp;
1600
1601 if (gn == NULL)
1602 return;
1603
1604 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++)
1605 zio_gang_tree_free(&gn->gn_child[g]);
1606
1607 zio_gang_node_free(gnpp);
1608 }
1609
1610 static void
1611 zio_gang_tree_assemble(zio_t *gio, blkptr_t *bp, zio_gang_node_t **gnpp)
1612 {
1613 zio_gang_node_t *gn = zio_gang_node_alloc(gnpp);
1614
1615 ASSERT(gio->io_gang_leader == gio);
1616 ASSERT(BP_IS_GANG(bp));
1617
1618 zio_nowait(zio_read(gio, gio->io_spa, bp, gn->gn_gbh,
1619 SPA_GANGBLOCKSIZE, zio_gang_tree_assemble_done, gn,
1620 gio->io_priority, ZIO_GANG_CHILD_FLAGS(gio), &gio->io_bookmark));
1621 }
1622
1623 static void
1624 zio_gang_tree_assemble_done(zio_t *zio)
1625 {
1626 zio_t *gio = zio->io_gang_leader;
1627 zio_gang_node_t *gn = zio->io_private;
1628 blkptr_t *bp = zio->io_bp;
1629
1630 ASSERT(gio == zio_unique_parent(zio));
1631 ASSERT(zio->io_child_count == 0);
1632
1633 if (zio->io_error)
1634 return;
1635
1636 if (BP_SHOULD_BYTESWAP(bp))
1637 byteswap_uint64_array(zio->io_data, zio->io_size);
1638
1639 ASSERT(zio->io_data == gn->gn_gbh);
1640 ASSERT(zio->io_size == SPA_GANGBLOCKSIZE);
1641 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC);
1642
1643 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
1644 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g];
1645 if (!BP_IS_GANG(gbp))
1646 continue;
1647 zio_gang_tree_assemble(gio, gbp, &gn->gn_child[g]);
1648 }
1649 }
1650
1651 static void
1652 zio_gang_tree_issue(zio_t *pio, zio_gang_node_t *gn, blkptr_t *bp, void *data)
1653 {
1654 zio_t *gio = pio->io_gang_leader;
1655 zio_t *zio;
1656
1657 ASSERT(BP_IS_GANG(bp) == !!gn);
1658 ASSERT(BP_GET_CHECKSUM(bp) == BP_GET_CHECKSUM(gio->io_bp));
1659 ASSERT(BP_GET_LSIZE(bp) == BP_GET_PSIZE(bp) || gn == gio->io_gang_tree);
1660
1661 /*
1662 * If you're a gang header, your data is in gn->gn_gbh.
1663 * If you're a gang member, your data is in 'data' and gn == NULL.
1664 */
1665 zio = zio_gang_issue_func[gio->io_type](pio, bp, gn, data);
1666
1667 if (gn != NULL) {
1668 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC);
1669
1670 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
1671 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g];
1672 if (BP_IS_HOLE(gbp))
1673 continue;
1674 zio_gang_tree_issue(zio, gn->gn_child[g], gbp, data);
1675 data = (char *)data + BP_GET_PSIZE(gbp);
1676 }
1677 }
1678
1679 if (gn == gio->io_gang_tree)
1680 ASSERT3P((char *)gio->io_data + gio->io_size, ==, data);
1681
1682 if (zio != pio)
1683 zio_nowait(zio);
1684 }
1685
1686 static int
1687 zio_gang_assemble(zio_t *zio)
1688 {
1689 blkptr_t *bp = zio->io_bp;
1690
1691 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == NULL);
1692 ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
1693
1694 zio->io_gang_leader = zio;
1695
1696 zio_gang_tree_assemble(zio, bp, &zio->io_gang_tree);
1697
1698 return (ZIO_PIPELINE_CONTINUE);
1699 }
1700
1701 static int
1702 zio_gang_issue(zio_t *zio)
1703 {
1704 blkptr_t *bp = zio->io_bp;
1705
1706 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE))
1707 return (ZIO_PIPELINE_STOP);
1708
1709 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == zio);
1710 ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
1711
1712 if (zio->io_child_error[ZIO_CHILD_GANG] == 0)
1713 zio_gang_tree_issue(zio, zio->io_gang_tree, bp, zio->io_data);
1714 else
1715 zio_gang_tree_free(&zio->io_gang_tree);
1716
1717 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1718
1719 return (ZIO_PIPELINE_CONTINUE);
1720 }
1721
1722 static void
1723 zio_write_gang_member_ready(zio_t *zio)
1724 {
1725 zio_t *pio = zio_unique_parent(zio);
1726 zio_t *gio = zio->io_gang_leader;
1727 dva_t *cdva = zio->io_bp->blk_dva;
1728 dva_t *pdva = pio->io_bp->blk_dva;
1729 uint64_t asize;
1730
1731 if (BP_IS_HOLE(zio->io_bp))
1732 return;
1733
1734 ASSERT(BP_IS_HOLE(&zio->io_bp_orig));
1735
1736 ASSERT(zio->io_child_type == ZIO_CHILD_GANG);
1737 ASSERT3U(zio->io_prop.zp_copies, ==, gio->io_prop.zp_copies);
1738 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(zio->io_bp));
1739 ASSERT3U(pio->io_prop.zp_copies, <=, BP_GET_NDVAS(pio->io_bp));
1740 ASSERT3U(BP_GET_NDVAS(zio->io_bp), <=, BP_GET_NDVAS(pio->io_bp));
1741
1742 mutex_enter(&pio->io_lock);
1743 for (int d = 0; d < BP_GET_NDVAS(zio->io_bp); d++) {
1744 ASSERT(DVA_GET_GANG(&pdva[d]));
1745 asize = DVA_GET_ASIZE(&pdva[d]);
1746 asize += DVA_GET_ASIZE(&cdva[d]);
1747 DVA_SET_ASIZE(&pdva[d], asize);
1748 }
1749 mutex_exit(&pio->io_lock);
1750 }
1751
1752 static int
1753 zio_write_gang_block(zio_t *pio)
1754 {
1755 spa_t *spa = pio->io_spa;
1756 blkptr_t *bp = pio->io_bp;
1757 zio_t *gio = pio->io_gang_leader;
1758 zio_t *zio;
1759 zio_gang_node_t *gn, **gnpp;
1760 zio_gbh_phys_t *gbh;
1761 uint64_t txg = pio->io_txg;
1762 uint64_t resid = pio->io_size;
1763 uint64_t lsize;
1764 int copies = gio->io_prop.zp_copies;
1765 int gbh_copies = MIN(copies + 1, spa_max_replication(spa));
1766 zio_prop_t zp;
1767 int error;
1768
1769 error = metaslab_alloc(spa, spa_normal_class(spa), SPA_GANGBLOCKSIZE,
1770 bp, gbh_copies, txg, pio == gio ? NULL : gio->io_bp,
1771 METASLAB_HINTBP_FAVOR | METASLAB_GANG_HEADER);
1772 if (error) {
1773 pio->io_error = error;
1774 return (ZIO_PIPELINE_CONTINUE);
1775 }
1776
1777 if (pio == gio) {
1778 gnpp = &gio->io_gang_tree;
1779 } else {
1780 gnpp = pio->io_private;
1781 ASSERT(pio->io_ready == zio_write_gang_member_ready);
1782 }
1783
1784 gn = zio_gang_node_alloc(gnpp);
1785 gbh = gn->gn_gbh;
1786 bzero(gbh, SPA_GANGBLOCKSIZE);
1787
1788 /*
1789 * Create the gang header.
1790 */
1791 zio = zio_rewrite(pio, spa, txg, bp, gbh, SPA_GANGBLOCKSIZE, NULL, NULL,
1792 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
1793
1794 /*
1795 * Create and nowait the gang children.
1796 */
1797 for (int g = 0; resid != 0; resid -= lsize, g++) {
1798 lsize = P2ROUNDUP(resid / (SPA_GBH_NBLKPTRS - g),
1799 SPA_MINBLOCKSIZE);
1800 ASSERT(lsize >= SPA_MINBLOCKSIZE && lsize <= resid);
1801
1802 zp.zp_checksum = gio->io_prop.zp_checksum;
1803 zp.zp_compress = ZIO_COMPRESS_OFF;
1804 zp.zp_type = DMU_OT_NONE;
1805 zp.zp_level = 0;
1806 zp.zp_copies = gio->io_prop.zp_copies;
1807 zp.zp_dedup = B_FALSE;
1808 zp.zp_dedup_verify = B_FALSE;
1809 zp.zp_nopwrite = B_FALSE;
1810
1811 zio_nowait(zio_write(zio, spa, txg, &gbh->zg_blkptr[g],
1812 (char *)pio->io_data + (pio->io_size - resid), lsize, &zp,
1813 zio_write_gang_member_ready, NULL, NULL, &gn->gn_child[g],
1814 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio),
1815 &pio->io_bookmark));
1816 }
1817
1818 /*
1819 * Set pio's pipeline to just wait for zio to finish.
1820 */
1821 pio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1822
1823 zio_nowait(zio);
1824
1825 return (ZIO_PIPELINE_CONTINUE);
1826 }
1827
1828 /*
1829 * The zio_nop_write stage in the pipeline determines if allocating
1830 * a new bp is necessary. By leveraging a cryptographically secure checksum,
1831 * such as SHA256, we can compare the checksums of the new data and the old
1832 * to determine if allocating a new block is required. The nopwrite
1833 * feature can handle writes in either syncing or open context (i.e. zil
1834 * writes) and as a result is mutually exclusive with dedup.
1835 */
1836 static int
1837 zio_nop_write(zio_t *zio)
1838 {
1839 blkptr_t *bp = zio->io_bp;
1840 blkptr_t *bp_orig = &zio->io_bp_orig;
1841 zio_prop_t *zp = &zio->io_prop;
1842
1843 ASSERT(BP_GET_LEVEL(bp) == 0);
1844 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE));
1845 ASSERT(zp->zp_nopwrite);
1846 ASSERT(!zp->zp_dedup);
1847 ASSERT(zio->io_bp_override == NULL);
1848 ASSERT(IO_IS_ALLOCATING(zio));
1849
1850 /*
1851 * Check to see if the original bp and the new bp have matching
1852 * characteristics (i.e. same checksum, compression algorithms, etc).
1853 * If they don't then just continue with the pipeline which will
1854 * allocate a new bp.
1855 */
1856 if (BP_IS_HOLE(bp_orig) ||
1857 !zio_checksum_table[BP_GET_CHECKSUM(bp)].ci_dedup ||
1858 BP_GET_CHECKSUM(bp) != BP_GET_CHECKSUM(bp_orig) ||
1859 BP_GET_COMPRESS(bp) != BP_GET_COMPRESS(bp_orig) ||
1860 BP_GET_DEDUP(bp) != BP_GET_DEDUP(bp_orig) ||
1861 zp->zp_copies != BP_GET_NDVAS(bp_orig))
1862 return (ZIO_PIPELINE_CONTINUE);
1863
1864 /*
1865 * If the checksums match then reset the pipeline so that we
1866 * avoid allocating a new bp and issuing any I/O.
1867 */
1868 if (ZIO_CHECKSUM_EQUAL(bp->blk_cksum, bp_orig->blk_cksum)) {
1869 ASSERT(zio_checksum_table[zp->zp_checksum].ci_dedup);
1870 ASSERT3U(BP_GET_PSIZE(bp), ==, BP_GET_PSIZE(bp_orig));
1871 ASSERT3U(BP_GET_LSIZE(bp), ==, BP_GET_LSIZE(bp_orig));
1872 ASSERT(zp->zp_compress != ZIO_COMPRESS_OFF);
1873 ASSERT(bcmp(&bp->blk_prop, &bp_orig->blk_prop,
1874 sizeof (uint64_t)) == 0);
1875
1876 *bp = *bp_orig;
1877 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1878 zio->io_flags |= ZIO_FLAG_NOPWRITE;
1879 }
1880
1881 return (ZIO_PIPELINE_CONTINUE);
1882 }
1883
1884 /*
1885 * ==========================================================================
1886 * Dedup
1887 * ==========================================================================
1888 */
1889 static void
1890 zio_ddt_child_read_done(zio_t *zio)
1891 {
1892 blkptr_t *bp = zio->io_bp;
1893 ddt_entry_t *dde = zio->io_private;
1894 ddt_phys_t *ddp;
1895 zio_t *pio = zio_unique_parent(zio);
1896
1897 mutex_enter(&pio->io_lock);
1898 ddp = ddt_phys_select(dde, bp);
1899 if (zio->io_error == 0)
1900 ddt_phys_clear(ddp); /* this ddp doesn't need repair */
1901 if (zio->io_error == 0 && dde->dde_repair_data == NULL)
1902 dde->dde_repair_data = zio->io_data;
1903 else
1904 zio_buf_free(zio->io_data, zio->io_size);
1905 mutex_exit(&pio->io_lock);
1906 }
1907
1908 static int
1909 zio_ddt_read_start(zio_t *zio)
1910 {
1911 blkptr_t *bp = zio->io_bp;
1912
1913 ASSERT(BP_GET_DEDUP(bp));
1914 ASSERT(BP_GET_PSIZE(bp) == zio->io_size);
1915 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1916
1917 if (zio->io_child_error[ZIO_CHILD_DDT]) {
1918 ddt_t *ddt = ddt_select(zio->io_spa, bp);
1919 ddt_entry_t *dde = ddt_repair_start(ddt, bp);
1920 ddt_phys_t *ddp = dde->dde_phys;
1921 ddt_phys_t *ddp_self = ddt_phys_select(dde, bp);
1922 blkptr_t blk;
1923
1924 ASSERT(zio->io_vsd == NULL);
1925 zio->io_vsd = dde;
1926
1927 if (ddp_self == NULL)
1928 return (ZIO_PIPELINE_CONTINUE);
1929
1930 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
1931 if (ddp->ddp_phys_birth == 0 || ddp == ddp_self)
1932 continue;
1933 ddt_bp_create(ddt->ddt_checksum, &dde->dde_key, ddp,
1934 &blk);
1935 zio_nowait(zio_read(zio, zio->io_spa, &blk,
1936 zio_buf_alloc(zio->io_size), zio->io_size,
1937 zio_ddt_child_read_done, dde, zio->io_priority,
1938 ZIO_DDT_CHILD_FLAGS(zio) | ZIO_FLAG_DONT_PROPAGATE,
1939 &zio->io_bookmark));
1940 }
1941 return (ZIO_PIPELINE_CONTINUE);
1942 }
1943
1944 zio_nowait(zio_read(zio, zio->io_spa, bp,
1945 zio->io_data, zio->io_size, NULL, NULL, zio->io_priority,
1946 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark));
1947
1948 return (ZIO_PIPELINE_CONTINUE);
1949 }
1950
1951 static int
1952 zio_ddt_read_done(zio_t *zio)
1953 {
1954 blkptr_t *bp = zio->io_bp;
1955
1956 if (zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE))
1957 return (ZIO_PIPELINE_STOP);
1958
1959 ASSERT(BP_GET_DEDUP(bp));
1960 ASSERT(BP_GET_PSIZE(bp) == zio->io_size);
1961 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1962
1963 if (zio->io_child_error[ZIO_CHILD_DDT]) {
1964 ddt_t *ddt = ddt_select(zio->io_spa, bp);
1965 ddt_entry_t *dde = zio->io_vsd;
1966 if (ddt == NULL) {
1967 ASSERT(spa_load_state(zio->io_spa) != SPA_LOAD_NONE);
1968 return (ZIO_PIPELINE_CONTINUE);
1969 }
1970 if (dde == NULL) {
1971 zio->io_stage = ZIO_STAGE_DDT_READ_START >> 1;
1972 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE);
1973 return (ZIO_PIPELINE_STOP);
1974 }
1975 if (dde->dde_repair_data != NULL) {
1976 bcopy(dde->dde_repair_data, zio->io_data, zio->io_size);
1977 zio->io_child_error[ZIO_CHILD_DDT] = 0;
1978 }
1979 ddt_repair_done(ddt, dde);
1980 zio->io_vsd = NULL;
1981 }
1982
1983 ASSERT(zio->io_vsd == NULL);
1984
1985 return (ZIO_PIPELINE_CONTINUE);
1986 }
1987
1988 static boolean_t
1989 zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde)
1990 {
1991 spa_t *spa = zio->io_spa;
1992
1993 /*
1994 * Note: we compare the original data, not the transformed data,
1995 * because when zio->io_bp is an override bp, we will not have
1996 * pushed the I/O transforms. That's an important optimization
1997 * because otherwise we'd compress/encrypt all dmu_sync() data twice.
1998 */
1999 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
2000 zio_t *lio = dde->dde_lead_zio[p];
2001
2002 if (lio != NULL) {
2003 return (lio->io_orig_size != zio->io_orig_size ||
2004 bcmp(zio->io_orig_data, lio->io_orig_data,
2005 zio->io_orig_size) != 0);
2006 }
2007 }
2008
2009 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
2010 ddt_phys_t *ddp = &dde->dde_phys[p];
2011
2012 if (ddp->ddp_phys_birth != 0) {
2013 arc_buf_t *abuf = NULL;
2014 uint32_t aflags = ARC_WAIT;
2015 blkptr_t blk = *zio->io_bp;
2016 int error;
2017
2018 ddt_bp_fill(ddp, &blk, ddp->ddp_phys_birth);
2019
2020 ddt_exit(ddt);
2021
2022 error = arc_read(NULL, spa, &blk,
2023 arc_getbuf_func, &abuf, ZIO_PRIORITY_SYNC_READ,
2024 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
2025 &aflags, &zio->io_bookmark);
2026
2027 if (error == 0) {
2028 if (arc_buf_size(abuf) != zio->io_orig_size ||
2029 bcmp(abuf->b_data, zio->io_orig_data,
2030 zio->io_orig_size) != 0)
2031 error = SET_ERROR(EEXIST);
2032 VERIFY(arc_buf_remove_ref(abuf, &abuf));
2033 }
2034
2035 ddt_enter(ddt);
2036 return (error != 0);
2037 }
2038 }
2039
2040 return (B_FALSE);
2041 }
2042
2043 static void
2044 zio_ddt_child_write_ready(zio_t *zio)
2045 {
2046 int p = zio->io_prop.zp_copies;
2047 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp);
2048 ddt_entry_t *dde = zio->io_private;
2049 ddt_phys_t *ddp = &dde->dde_phys[p];
2050 zio_t *pio;
2051
2052 if (zio->io_error)
2053 return;
2054
2055 ddt_enter(ddt);
2056
2057 ASSERT(dde->dde_lead_zio[p] == zio);
2058
2059 ddt_phys_fill(ddp, zio->io_bp);
2060
2061 while ((pio = zio_walk_parents(zio)) != NULL)
2062 ddt_bp_fill(ddp, pio->io_bp, zio->io_txg);
2063
2064 ddt_exit(ddt);
2065 }
2066
2067 static void
2068 zio_ddt_child_write_done(zio_t *zio)
2069 {
2070 int p = zio->io_prop.zp_copies;
2071 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp);
2072 ddt_entry_t *dde = zio->io_private;
2073 ddt_phys_t *ddp = &dde->dde_phys[p];
2074
2075 ddt_enter(ddt);
2076
2077 ASSERT(ddp->ddp_refcnt == 0);
2078 ASSERT(dde->dde_lead_zio[p] == zio);
2079 dde->dde_lead_zio[p] = NULL;
2080
2081 if (zio->io_error == 0) {
2082 while (zio_walk_parents(zio) != NULL)
2083 ddt_phys_addref(ddp);
2084 } else {
2085 ddt_phys_clear(ddp);
2086 }
2087
2088 ddt_exit(ddt);
2089 }
2090
2091 static void
2092 zio_ddt_ditto_write_done(zio_t *zio)
2093 {
2094 int p = DDT_PHYS_DITTO;
2095 zio_prop_t *zp = &zio->io_prop;
2096 blkptr_t *bp = zio->io_bp;
2097 ddt_t *ddt = ddt_select(zio->io_spa, bp);
2098 ddt_entry_t *dde = zio->io_private;
2099 ddt_phys_t *ddp = &dde->dde_phys[p];
2100 ddt_key_t *ddk = &dde->dde_key;
2101
2102 ddt_enter(ddt);
2103
2104 ASSERT(ddp->ddp_refcnt == 0);
2105 ASSERT(dde->dde_lead_zio[p] == zio);
2106 dde->dde_lead_zio[p] = NULL;
2107
2108 if (zio->io_error == 0) {
2109 ASSERT(ZIO_CHECKSUM_EQUAL(bp->blk_cksum, ddk->ddk_cksum));
2110 ASSERT(zp->zp_copies < SPA_DVAS_PER_BP);
2111 ASSERT(zp->zp_copies == BP_GET_NDVAS(bp) - BP_IS_GANG(bp));
2112 if (ddp->ddp_phys_birth != 0)
2113 ddt_phys_free(ddt, ddk, ddp, zio->io_txg);
2114 ddt_phys_fill(ddp, bp);
2115 }
2116
2117 ddt_exit(ddt);
2118 }
2119
2120 static int
2121 zio_ddt_write(zio_t *zio)
2122 {
2123 spa_t *spa = zio->io_spa;
2124 blkptr_t *bp = zio->io_bp;
2125 uint64_t txg = zio->io_txg;
2126 zio_prop_t *zp = &zio->io_prop;
2127 int p = zp->zp_copies;
2128 int ditto_copies;
2129 zio_t *cio = NULL;
2130 zio_t *dio = NULL;
2131 ddt_t *ddt = ddt_select(spa, bp);
2132 ddt_entry_t *dde;
2133 ddt_phys_t *ddp;
2134
2135 ASSERT(BP_GET_DEDUP(bp));
2136 ASSERT(BP_GET_CHECKSUM(bp) == zp->zp_checksum);
2137 ASSERT(BP_IS_HOLE(bp) || zio->io_bp_override);
2138
2139 ddt_enter(ddt);
2140 dde = ddt_lookup(ddt, bp, B_TRUE);
2141 ddp = &dde->dde_phys[p];
2142
2143 if (zp->zp_dedup_verify && zio_ddt_collision(zio, ddt, dde)) {
2144 /*
2145 * If we're using a weak checksum, upgrade to a strong checksum
2146 * and try again. If we're already using a strong checksum,
2147 * we can't resolve it, so just convert to an ordinary write.
2148 * (And automatically e-mail a paper to Nature?)
2149 */
2150 if (!zio_checksum_table[zp->zp_checksum].ci_dedup) {
2151 zp->zp_checksum = spa_dedup_checksum(spa);
2152 zio_pop_transforms(zio);
2153 zio->io_stage = ZIO_STAGE_OPEN;
2154 BP_ZERO(bp);
2155 } else {
2156 zp->zp_dedup = B_FALSE;
2157 }
2158 zio->io_pipeline = ZIO_WRITE_PIPELINE;
2159 ddt_exit(ddt);
2160 return (ZIO_PIPELINE_CONTINUE);
2161 }
2162
2163 ditto_copies = ddt_ditto_copies_needed(ddt, dde, ddp);
2164 ASSERT(ditto_copies < SPA_DVAS_PER_BP);
2165
2166 if (ditto_copies > ddt_ditto_copies_present(dde) &&
2167 dde->dde_lead_zio[DDT_PHYS_DITTO] == NULL) {
2168 zio_prop_t czp = *zp;
2169
2170 czp.zp_copies = ditto_copies;
2171
2172 /*
2173 * If we arrived here with an override bp, we won't have run
2174 * the transform stack, so we won't have the data we need to
2175 * generate a child i/o. So, toss the override bp and restart.
2176 * This is safe, because using the override bp is just an
2177 * optimization; and it's rare, so the cost doesn't matter.
2178 */
2179 if (zio->io_bp_override) {
2180 zio_pop_transforms(zio);
2181 zio->io_stage = ZIO_STAGE_OPEN;
2182 zio->io_pipeline = ZIO_WRITE_PIPELINE;
2183 zio->io_bp_override = NULL;
2184 BP_ZERO(bp);
2185 ddt_exit(ddt);
2186 return (ZIO_PIPELINE_CONTINUE);
2187 }
2188
2189 dio = zio_write(zio, spa, txg, bp, zio->io_orig_data,
2190 zio->io_orig_size, &czp, NULL, NULL,
2191 zio_ddt_ditto_write_done, dde, zio->io_priority,
2192 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark);
2193
2194 zio_push_transform(dio, zio->io_data, zio->io_size, 0, NULL);
2195 dde->dde_lead_zio[DDT_PHYS_DITTO] = dio;
2196 }
2197
2198 if (ddp->ddp_phys_birth != 0 || dde->dde_lead_zio[p] != NULL) {
2199 if (ddp->ddp_phys_birth != 0)
2200 ddt_bp_fill(ddp, bp, txg);
2201 if (dde->dde_lead_zio[p] != NULL)
2202 zio_add_child(zio, dde->dde_lead_zio[p]);
2203 else
2204 ddt_phys_addref(ddp);
2205 } else if (zio->io_bp_override) {
2206 ASSERT(bp->blk_birth == txg);
2207 ASSERT(BP_EQUAL(bp, zio->io_bp_override));
2208 ddt_phys_fill(ddp, bp);
2209 ddt_phys_addref(ddp);
2210 } else {
2211 cio = zio_write(zio, spa, txg, bp, zio->io_orig_data,
2212 zio->io_orig_size, zp, zio_ddt_child_write_ready, NULL,
2213 zio_ddt_child_write_done, dde, zio->io_priority,
2214 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark);
2215
2216 zio_push_transform(cio, zio->io_data, zio->io_size, 0, NULL);
2217 dde->dde_lead_zio[p] = cio;
2218 }
2219
2220 ddt_exit(ddt);
2221
2222 if (cio)
2223 zio_nowait(cio);
2224 if (dio)
2225 zio_nowait(dio);
2226
2227 return (ZIO_PIPELINE_CONTINUE);
2228 }
2229
2230 ddt_entry_t *freedde; /* for debugging */
2231
2232 static int
2233 zio_ddt_free(zio_t *zio)
2234 {
2235 spa_t *spa = zio->io_spa;
2236 blkptr_t *bp = zio->io_bp;
2237 ddt_t *ddt = ddt_select(spa, bp);
2238 ddt_entry_t *dde;
2239 ddt_phys_t *ddp;
2240
2241 ASSERT(BP_GET_DEDUP(bp));
2242 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
2243
2244 ddt_enter(ddt);
2245 freedde = dde = ddt_lookup(ddt, bp, B_TRUE);
2246 ddp = ddt_phys_select(dde, bp);
2247 ddt_phys_decref(ddp);
2248 ddt_exit(ddt);
2249
2250 return (ZIO_PIPELINE_CONTINUE);
2251 }
2252
2253 /*
2254 * ==========================================================================
2255 * Allocate and free blocks
2256 * ==========================================================================
2257 */
2258 static int
2259 zio_dva_allocate(zio_t *zio)
2260 {
2261 spa_t *spa = zio->io_spa;
2262 metaslab_class_t *mc = spa_normal_class(spa);
2263 blkptr_t *bp = zio->io_bp;
2264 int error;
2265 int flags = 0;
2266
2267 if (zio->io_gang_leader == NULL) {
2268 ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
2269 zio->io_gang_leader = zio;
2270 }
2271
2272 ASSERT(BP_IS_HOLE(bp));
2273 ASSERT0(BP_GET_NDVAS(bp));
2274 ASSERT3U(zio->io_prop.zp_copies, >, 0);
2275 ASSERT3U(zio->io_prop.zp_copies, <=, spa_max_replication(spa));
2276 ASSERT3U(zio->io_size, ==, BP_GET_PSIZE(bp));
2277
2278 /*
2279 * The dump device does not support gang blocks so allocation on
2280 * behalf of the dump device (i.e. ZIO_FLAG_NODATA) must avoid
2281 * the "fast" gang feature.
2282 */
2283 flags |= (zio->io_flags & ZIO_FLAG_NODATA) ? METASLAB_GANG_AVOID : 0;
2284 flags |= (zio->io_flags & ZIO_FLAG_GANG_CHILD) ?
2285 METASLAB_GANG_CHILD : 0;
2286 error = metaslab_alloc(spa, mc, zio->io_size, bp,
2287 zio->io_prop.zp_copies, zio->io_txg, NULL, flags);
2288
2289 if (error) {
2290 spa_dbgmsg(spa, "%s: metaslab allocation failure: zio %p, "
2291 "size %llu, error %d", spa_name(spa), zio, zio->io_size,
2292 error);
2293 if (error == ENOSPC && zio->io_size > SPA_MINBLOCKSIZE)
2294 return (zio_write_gang_block(zio));
2295 zio->io_error = error;
2296 }
2297
2298 return (ZIO_PIPELINE_CONTINUE);
2299 }
2300
2301 static int
2302 zio_dva_free(zio_t *zio)
2303 {
2304 metaslab_free(zio->io_spa, zio->io_bp, zio->io_txg, B_FALSE);
2305
2306 return (ZIO_PIPELINE_CONTINUE);
2307 }
2308
2309 static int
2310 zio_dva_claim(zio_t *zio)
2311 {
2312 int error;
2313
2314 error = metaslab_claim(zio->io_spa, zio->io_bp, zio->io_txg);
2315 if (error)
2316 zio->io_error = error;
2317
2318 return (ZIO_PIPELINE_CONTINUE);
2319 }
2320
2321 /*
2322 * Undo an allocation. This is used by zio_done() when an I/O fails
2323 * and we want to give back the block we just allocated.
2324 * This handles both normal blocks and gang blocks.
2325 */
2326 static void
2327 zio_dva_unallocate(zio_t *zio, zio_gang_node_t *gn, blkptr_t *bp)
2328 {
2329 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp));
2330 ASSERT(zio->io_bp_override == NULL);
2331
2332 if (!BP_IS_HOLE(bp))
2333 metaslab_free(zio->io_spa, bp, bp->blk_birth, B_TRUE);
2334
2335 if (gn != NULL) {
2336 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
2337 zio_dva_unallocate(zio, gn->gn_child[g],
2338 &gn->gn_gbh->zg_blkptr[g]);
2339 }
2340 }
2341 }
2342
2343 /*
2344 * Try to allocate an intent log block. Return 0 on success, errno on failure.
2345 */
2346 int
2347 zio_alloc_zil(spa_t *spa, uint64_t txg, blkptr_t *new_bp, blkptr_t *old_bp,
2348 uint64_t size, boolean_t use_slog)
2349 {
2350 int error = 1;
2351
2352 ASSERT(txg > spa_syncing_txg(spa));
2353
2354 /*
2355 * ZIL blocks are always contiguous (i.e. not gang blocks) so we
2356 * set the METASLAB_GANG_AVOID flag so that they don't "fast gang"
2357 * when allocating them.
2358 */
2359 if (use_slog) {
2360 error = metaslab_alloc(spa, spa_log_class(spa), size,
2361 new_bp, 1, txg, old_bp,
2362 METASLAB_HINTBP_AVOID | METASLAB_GANG_AVOID);
2363 }
2364
2365 if (error) {
2366 error = metaslab_alloc(spa, spa_normal_class(spa), size,
2367 new_bp, 1, txg, old_bp,
2368 METASLAB_HINTBP_AVOID | METASLAB_GANG_AVOID);
2369 }
2370
2371 if (error == 0) {
2372 BP_SET_LSIZE(new_bp, size);
2373 BP_SET_PSIZE(new_bp, size);
2374 BP_SET_COMPRESS(new_bp, ZIO_COMPRESS_OFF);
2375 BP_SET_CHECKSUM(new_bp,
2376 spa_version(spa) >= SPA_VERSION_SLIM_ZIL
2377 ? ZIO_CHECKSUM_ZILOG2 : ZIO_CHECKSUM_ZILOG);
2378 BP_SET_TYPE(new_bp, DMU_OT_INTENT_LOG);
2379 BP_SET_LEVEL(new_bp, 0);
2380 BP_SET_DEDUP(new_bp, 0);
2381 BP_SET_BYTEORDER(new_bp, ZFS_HOST_BYTEORDER);
2382 }
2383
2384 return (error);
2385 }
2386
2387 /*
2388 * Free an intent log block.
2389 */
2390 void
2391 zio_free_zil(spa_t *spa, uint64_t txg, blkptr_t *bp)
2392 {
2393 ASSERT(BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG);
2394 ASSERT(!BP_IS_GANG(bp));
2395
2396 zio_free(spa, txg, bp);
2397 }
2398
2399 /*
2400 * ==========================================================================
2401 * Read and write to physical devices
2402 * ==========================================================================
2403 */
2404 static int
2405 zio_vdev_io_start(zio_t *zio)
2406 {
2407 vdev_t *vd = zio->io_vd;
2408 uint64_t align;
2409 spa_t *spa = zio->io_spa;
2410
2411 ASSERT(zio->io_error == 0);
2412 ASSERT(zio->io_child_error[ZIO_CHILD_VDEV] == 0);
2413
2414 if (vd == NULL) {
2415 if (!(zio->io_flags & ZIO_FLAG_CONFIG_WRITER))
2416 spa_config_enter(spa, SCL_ZIO, zio, RW_READER);
2417
2418 /*
2419 * The mirror_ops handle multiple DVAs in a single BP.
2420 */
2421 return (vdev_mirror_ops.vdev_op_io_start(zio));
2422 }
2423
2424 /*
2425 * We keep track of time-sensitive I/Os so that the scan thread
2426 * can quickly react to certain workloads. In particular, we care
2427 * about non-scrubbing, top-level reads and writes with the following
2428 * characteristics:
2429 * - synchronous writes of user data to non-slog devices
2430 * - any reads of user data
2431 * When these conditions are met, adjust the timestamp of spa_last_io
2432 * which allows the scan thread to adjust its workload accordingly.
2433 */
2434 if (!(zio->io_flags & ZIO_FLAG_SCAN_THREAD) && zio->io_bp != NULL &&
2435 vd == vd->vdev_top && !vd->vdev_islog &&
2436 zio->io_bookmark.zb_objset != DMU_META_OBJSET &&
2437 zio->io_txg != spa_syncing_txg(spa)) {
2438 uint64_t old = spa->spa_last_io;
2439 uint64_t new = ddi_get_lbolt64();
2440 if (old != new)
2441 (void) atomic_cas_64(&spa->spa_last_io, old, new);
2442 }
2443
2444 align = 1ULL << vd->vdev_top->vdev_ashift;
2445
2446 if (P2PHASE(zio->io_size, align) != 0) {
2447 uint64_t asize = P2ROUNDUP(zio->io_size, align);
2448 char *abuf = zio_buf_alloc(asize);
2449 ASSERT(vd == vd->vdev_top);
2450 if (zio->io_type == ZIO_TYPE_WRITE) {
2451 bcopy(zio->io_data, abuf, zio->io_size);
2452 bzero(abuf + zio->io_size, asize - zio->io_size);
2453 }
2454 zio_push_transform(zio, abuf, asize, asize, zio_subblock);
2455 }
2456
2457 ASSERT(P2PHASE(zio->io_offset, align) == 0);
2458 ASSERT(P2PHASE(zio->io_size, align) == 0);
2459 VERIFY(zio->io_type != ZIO_TYPE_WRITE || spa_writeable(spa));
2460
2461 /*
2462 * If this is a repair I/O, and there's no self-healing involved --
2463 * that is, we're just resilvering what we expect to resilver --
2464 * then don't do the I/O unless zio's txg is actually in vd's DTL.
2465 * This prevents spurious resilvering with nested replication.
2466 * For example, given a mirror of mirrors, (A+B)+(C+D), if only
2467 * A is out of date, we'll read from C+D, then use the data to
2468 * resilver A+B -- but we don't actually want to resilver B, just A.
2469 * The top-level mirror has no way to know this, so instead we just
2470 * discard unnecessary repairs as we work our way down the vdev tree.
2471 * The same logic applies to any form of nested replication:
2472 * ditto + mirror, RAID-Z + replacing, etc. This covers them all.
2473 */
2474 if ((zio->io_flags & ZIO_FLAG_IO_REPAIR) &&
2475 !(zio->io_flags & ZIO_FLAG_SELF_HEAL) &&
2476 zio->io_txg != 0 && /* not a delegated i/o */
2477 !vdev_dtl_contains(vd, DTL_PARTIAL, zio->io_txg, 1)) {
2478 ASSERT(zio->io_type == ZIO_TYPE_WRITE);
2479 zio_vdev_io_bypass(zio);
2480 return (ZIO_PIPELINE_CONTINUE);
2481 }
2482
2483 if (vd->vdev_ops->vdev_op_leaf &&
2484 (zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE)) {
2485
2486 if (zio->io_type == ZIO_TYPE_READ && vdev_cache_read(zio) == 0)
2487 return (ZIO_PIPELINE_CONTINUE);
2488
2489 if ((zio = vdev_queue_io(zio)) == NULL)
2490 return (ZIO_PIPELINE_STOP);
2491
2492 if (!vdev_accessible(vd, zio)) {
2493 zio->io_error = SET_ERROR(ENXIO);
2494 zio_interrupt(zio);
2495 return (ZIO_PIPELINE_STOP);
2496 }
2497 }
2498
2499 return (vd->vdev_ops->vdev_op_io_start(zio));
2500 }
2501
2502 static int
2503 zio_vdev_io_done(zio_t *zio)
2504 {
2505 vdev_t *vd = zio->io_vd;
2506 vdev_ops_t *ops = vd ? vd->vdev_ops : &vdev_mirror_ops;
2507 boolean_t unexpected_error = B_FALSE;
2508
2509 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE))
2510 return (ZIO_PIPELINE_STOP);
2511
2512 ASSERT(zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE);
2513
2514 if (vd != NULL && vd->vdev_ops->vdev_op_leaf) {
2515
2516 vdev_queue_io_done(zio);
2517
2518 if (zio->io_type == ZIO_TYPE_WRITE)
2519 vdev_cache_write(zio);
2520
2521 if (zio_injection_enabled && zio->io_error == 0)
2522 zio->io_error = zio_handle_device_injection(vd,
2523 zio, EIO);
2524
2525 if (zio_injection_enabled && zio->io_error == 0)
2526 zio->io_error = zio_handle_label_injection(zio, EIO);
2527
2528 if (zio->io_error) {
2529 if (!vdev_accessible(vd, zio)) {
2530 zio->io_error = SET_ERROR(ENXIO);
2531 } else {
2532 unexpected_error = B_TRUE;
2533 }
2534 }
2535 }
2536
2537 ops->vdev_op_io_done(zio);
2538
2539 if (unexpected_error)
2540 VERIFY(vdev_probe(vd, zio) == NULL);
2541
2542 return (ZIO_PIPELINE_CONTINUE);
2543 }
2544
2545 /*
2546 * For non-raidz ZIOs, we can just copy aside the bad data read from the
2547 * disk, and use that to finish the checksum ereport later.
2548 */
2549 static void
2550 zio_vsd_default_cksum_finish(zio_cksum_report_t *zcr,
2551 const void *good_buf)
2552 {
2553 /* no processing needed */
2554 zfs_ereport_finish_checksum(zcr, good_buf, zcr->zcr_cbdata, B_FALSE);
2555 }
2556
2557 /*ARGSUSED*/
2558 void
2559 zio_vsd_default_cksum_report(zio_t *zio, zio_cksum_report_t *zcr, void *ignored)
2560 {
2561 void *buf = zio_buf_alloc(zio->io_size);
2562
2563 bcopy(zio->io_data, buf, zio->io_size);
2564
2565 zcr->zcr_cbinfo = zio->io_size;
2566 zcr->zcr_cbdata = buf;
2567 zcr->zcr_finish = zio_vsd_default_cksum_finish;
2568 zcr->zcr_free = zio_buf_free;
2569 }
2570
2571 static int
2572 zio_vdev_io_assess(zio_t *zio)
2573 {
2574 vdev_t *vd = zio->io_vd;
2575
2576 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE))
2577 return (ZIO_PIPELINE_STOP);
2578
2579 if (vd == NULL && !(zio->io_flags & ZIO_FLAG_CONFIG_WRITER))
2580 spa_config_exit(zio->io_spa, SCL_ZIO, zio);
2581
2582 if (zio->io_vsd != NULL) {
2583 zio->io_vsd_ops->vsd_free(zio);
2584 zio->io_vsd = NULL;
2585 }
2586
2587 if (zio_injection_enabled && zio->io_error == 0)
2588 zio->io_error = zio_handle_fault_injection(zio, EIO);
2589
2590 /*
2591 * If the I/O failed, determine whether we should attempt to retry it.
2592 *
2593 * On retry, we cut in line in the issue queue, since we don't want
2594 * compression/checksumming/etc. work to prevent our (cheap) IO reissue.
2595 */
2596 if (zio->io_error && vd == NULL &&
2597 !(zio->io_flags & (ZIO_FLAG_DONT_RETRY | ZIO_FLAG_IO_RETRY))) {
2598 ASSERT(!(zio->io_flags & ZIO_FLAG_DONT_QUEUE)); /* not a leaf */
2599 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_BYPASS)); /* not a leaf */
2600 zio->io_error = 0;
2601 zio->io_flags |= ZIO_FLAG_IO_RETRY |
2602 ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE;
2603 zio->io_stage = ZIO_STAGE_VDEV_IO_START >> 1;
2604 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE,
2605 zio_requeue_io_start_cut_in_line);
2606 return (ZIO_PIPELINE_STOP);
2607 }
2608
2609 /*
2610 * If we got an error on a leaf device, convert it to ENXIO
2611 * if the device is not accessible at all.
2612 */
2613 if (zio->io_error && vd != NULL && vd->vdev_ops->vdev_op_leaf &&
2614 !vdev_accessible(vd, zio))
2615 zio->io_error = SET_ERROR(ENXIO);
2616
2617 /*
2618 * If we can't write to an interior vdev (mirror or RAID-Z),
2619 * set vdev_cant_write so that we stop trying to allocate from it.
2620 */
2621 if (zio->io_error == ENXIO && zio->io_type == ZIO_TYPE_WRITE &&
2622 vd != NULL && !vd->vdev_ops->vdev_op_leaf) {
2623 vd->vdev_cant_write = B_TRUE;
2624 }
2625
2626 if (zio->io_error)
2627 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
2628
2629 if (vd != NULL && vd->vdev_ops->vdev_op_leaf &&
2630 zio->io_physdone != NULL) {
2631 ASSERT(!(zio->io_flags & ZIO_FLAG_DELEGATED));
2632 ASSERT(zio->io_child_type == ZIO_CHILD_VDEV);
2633 zio->io_physdone(zio->io_logical);
2634 }
2635
2636 return (ZIO_PIPELINE_CONTINUE);
2637 }
2638
2639 void
2640 zio_vdev_io_reissue(zio_t *zio)
2641 {
2642 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START);
2643 ASSERT(zio->io_error == 0);
2644
2645 zio->io_stage >>= 1;
2646 }
2647
2648 void
2649 zio_vdev_io_redone(zio_t *zio)
2650 {
2651 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_DONE);
2652
2653 zio->io_stage >>= 1;
2654 }
2655
2656 void
2657 zio_vdev_io_bypass(zio_t *zio)
2658 {
2659 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START);
2660 ASSERT(zio->io_error == 0);
2661
2662 zio->io_flags |= ZIO_FLAG_IO_BYPASS;
2663 zio->io_stage = ZIO_STAGE_VDEV_IO_ASSESS >> 1;
2664 }
2665
2666 /*
2667 * ==========================================================================
2668 * Generate and verify checksums
2669 * ==========================================================================
2670 */
2671 static int
2672 zio_checksum_generate(zio_t *zio)
2673 {
2674 blkptr_t *bp = zio->io_bp;
2675 enum zio_checksum checksum;
2676
2677 if (bp == NULL) {
2678 /*
2679 * This is zio_write_phys().
2680 * We're either generating a label checksum, or none at all.
2681 */
2682 checksum = zio->io_prop.zp_checksum;
2683
2684 if (checksum == ZIO_CHECKSUM_OFF)
2685 return (ZIO_PIPELINE_CONTINUE);
2686
2687 ASSERT(checksum == ZIO_CHECKSUM_LABEL);
2688 } else {
2689 if (BP_IS_GANG(bp) && zio->io_child_type == ZIO_CHILD_GANG) {
2690 ASSERT(!IO_IS_ALLOCATING(zio));
2691 checksum = ZIO_CHECKSUM_GANG_HEADER;
2692 } else {
2693 checksum = BP_GET_CHECKSUM(bp);
2694 }
2695 }
2696
2697 zio_checksum_compute(zio, checksum, zio->io_data, zio->io_size);
2698
2699 return (ZIO_PIPELINE_CONTINUE);
2700 }
2701
2702 static int
2703 zio_checksum_verify(zio_t *zio)
2704 {
2705 zio_bad_cksum_t info;
2706 blkptr_t *bp = zio->io_bp;
2707 int error;
2708
2709 ASSERT(zio->io_vd != NULL);
2710
2711 if (bp == NULL) {
2712 /*
2713 * This is zio_read_phys().
2714 * We're either verifying a label checksum, or nothing at all.
2715 */
2716 if (zio->io_prop.zp_checksum == ZIO_CHECKSUM_OFF)
2717 return (ZIO_PIPELINE_CONTINUE);
2718
2719 ASSERT(zio->io_prop.zp_checksum == ZIO_CHECKSUM_LABEL);
2720 }
2721
2722 if ((error = zio_checksum_error(zio, &info)) != 0) {
2723 zio->io_error = error;
2724 if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) {
2725 zfs_ereport_start_checksum(zio->io_spa,
2726 zio->io_vd, zio, zio->io_offset,
2727 zio->io_size, NULL, &info);
2728 }
2729 }
2730
2731 return (ZIO_PIPELINE_CONTINUE);
2732 }
2733
2734 /*
2735 * Called by RAID-Z to ensure we don't compute the checksum twice.
2736 */
2737 void
2738 zio_checksum_verified(zio_t *zio)
2739 {
2740 zio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY;
2741 }
2742
2743 /*
2744 * ==========================================================================
2745 * Error rank. Error are ranked in the order 0, ENXIO, ECKSUM, EIO, other.
2746 * An error of 0 indictes success. ENXIO indicates whole-device failure,
2747 * which may be transient (e.g. unplugged) or permament. ECKSUM and EIO
2748 * indicate errors that are specific to one I/O, and most likely permanent.
2749 * Any other error is presumed to be worse because we weren't expecting it.
2750 * ==========================================================================
2751 */
2752 int
2753 zio_worst_error(int e1, int e2)
2754 {
2755 static int zio_error_rank[] = { 0, ENXIO, ECKSUM, EIO };
2756 int r1, r2;
2757
2758 for (r1 = 0; r1 < sizeof (zio_error_rank) / sizeof (int); r1++)
2759 if (e1 == zio_error_rank[r1])
2760 break;
2761
2762 for (r2 = 0; r2 < sizeof (zio_error_rank) / sizeof (int); r2++)
2763 if (e2 == zio_error_rank[r2])
2764 break;
2765
2766 return (r1 > r2 ? e1 : e2);
2767 }
2768
2769 /*
2770 * ==========================================================================
2771 * I/O completion
2772 * ==========================================================================
2773 */
2774 static int
2775 zio_ready(zio_t *zio)
2776 {
2777 blkptr_t *bp = zio->io_bp;
2778 zio_t *pio, *pio_next;
2779
2780 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) ||
2781 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_READY))
2782 return (ZIO_PIPELINE_STOP);
2783
2784 if (zio->io_ready) {
2785 ASSERT(IO_IS_ALLOCATING(zio));
2786 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp) ||
2787 (zio->io_flags & ZIO_FLAG_NOPWRITE));
2788 ASSERT(zio->io_children[ZIO_CHILD_GANG][ZIO_WAIT_READY] == 0);
2789
2790 zio->io_ready(zio);
2791 }
2792
2793 if (bp != NULL && bp != &zio->io_bp_copy)
2794 zio->io_bp_copy = *bp;
2795
2796 if (zio->io_error)
2797 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
2798
2799 mutex_enter(&zio->io_lock);
2800 zio->io_state[ZIO_WAIT_READY] = 1;
2801 pio = zio_walk_parents(zio);
2802 mutex_exit(&zio->io_lock);
2803
2804 /*
2805 * As we notify zio's parents, new parents could be added.
2806 * New parents go to the head of zio's io_parent_list, however,
2807 * so we will (correctly) not notify them. The remainder of zio's
2808 * io_parent_list, from 'pio_next' onward, cannot change because
2809 * all parents must wait for us to be done before they can be done.
2810 */
2811 for (; pio != NULL; pio = pio_next) {
2812 pio_next = zio_walk_parents(zio);
2813 zio_notify_parent(pio, zio, ZIO_WAIT_READY);
2814 }
2815
2816 if (zio->io_flags & ZIO_FLAG_NODATA) {
2817 if (BP_IS_GANG(bp)) {
2818 zio->io_flags &= ~ZIO_FLAG_NODATA;
2819 } else {
2820 ASSERT((uintptr_t)zio->io_data < SPA_MAXBLOCKSIZE);
2821 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES;
2822 }
2823 }
2824
2825 if (zio_injection_enabled &&
2826 zio->io_spa->spa_syncing_txg == zio->io_txg)
2827 zio_handle_ignored_writes(zio);
2828
2829 return (ZIO_PIPELINE_CONTINUE);
2830 }
2831
2832 static int
2833 zio_done(zio_t *zio)
2834 {
2835 spa_t *spa = zio->io_spa;
2836 zio_t *lio = zio->io_logical;
2837 blkptr_t *bp = zio->io_bp;
2838 vdev_t *vd = zio->io_vd;
2839 uint64_t psize = zio->io_size;
2840 zio_t *pio, *pio_next;
2841
2842 /*
2843 * If our children haven't all completed,
2844 * wait for them and then repeat this pipeline stage.
2845 */
2846 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE) ||
2847 zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE) ||
2848 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE) ||
2849 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_DONE))
2850 return (ZIO_PIPELINE_STOP);
2851
2852 for (int c = 0; c < ZIO_CHILD_TYPES; c++)
2853 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
2854 ASSERT(zio->io_children[c][w] == 0);
2855
2856 if (bp != NULL) {
2857 ASSERT(bp->blk_pad[0] == 0);
2858 ASSERT(bp->blk_pad[1] == 0);
2859 ASSERT(bcmp(bp, &zio->io_bp_copy, sizeof (blkptr_t)) == 0 ||
2860 (bp == zio_unique_parent(zio)->io_bp));
2861 if (zio->io_type == ZIO_TYPE_WRITE && !BP_IS_HOLE(bp) &&
2862 zio->io_bp_override == NULL &&
2863 !(zio->io_flags & ZIO_FLAG_IO_REPAIR)) {
2864 ASSERT(!BP_SHOULD_BYTESWAP(bp));
2865 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(bp));
2866 ASSERT(BP_COUNT_GANG(bp) == 0 ||
2867 (BP_COUNT_GANG(bp) == BP_GET_NDVAS(bp)));
2868 }
2869 if (zio->io_flags & ZIO_FLAG_NOPWRITE)
2870 VERIFY(BP_EQUAL(bp, &zio->io_bp_orig));
2871 }
2872
2873 /*
2874 * If there were child vdev/gang/ddt errors, they apply to us now.
2875 */
2876 zio_inherit_child_errors(zio, ZIO_CHILD_VDEV);
2877 zio_inherit_child_errors(zio, ZIO_CHILD_GANG);
2878 zio_inherit_child_errors(zio, ZIO_CHILD_DDT);
2879
2880 /*
2881 * If the I/O on the transformed data was successful, generate any
2882 * checksum reports now while we still have the transformed data.
2883 */
2884 if (zio->io_error == 0) {
2885 while (zio->io_cksum_report != NULL) {
2886 zio_cksum_report_t *zcr = zio->io_cksum_report;
2887 uint64_t align = zcr->zcr_align;
2888 uint64_t asize = P2ROUNDUP(psize, align);
2889 char *abuf = zio->io_data;
2890
2891 if (asize != psize) {
2892 abuf = zio_buf_alloc(asize);
2893 bcopy(zio->io_data, abuf, psize);
2894 bzero(abuf + psize, asize - psize);
2895 }
2896
2897 zio->io_cksum_report = zcr->zcr_next;
2898 zcr->zcr_next = NULL;
2899 zcr->zcr_finish(zcr, abuf);
2900 zfs_ereport_free_checksum(zcr);
2901
2902 if (asize != psize)
2903 zio_buf_free(abuf, asize);
2904 }
2905 }
2906
2907 zio_pop_transforms(zio); /* note: may set zio->io_error */
2908
2909 vdev_stat_update(zio, psize);
2910
2911 if (zio->io_error) {
2912 /*
2913 * If this I/O is attached to a particular vdev,
2914 * generate an error message describing the I/O failure
2915 * at the block level. We ignore these errors if the
2916 * device is currently unavailable.
2917 */
2918 if (zio->io_error != ECKSUM && vd != NULL && !vdev_is_dead(vd))
2919 zfs_ereport_post(FM_EREPORT_ZFS_IO, spa, vd, zio, 0, 0);
2920
2921 if ((zio->io_error == EIO || !(zio->io_flags &
2922 (ZIO_FLAG_SPECULATIVE | ZIO_FLAG_DONT_PROPAGATE))) &&
2923 zio == lio) {
2924 /*
2925 * For logical I/O requests, tell the SPA to log the
2926 * error and generate a logical data ereport.
2927 */
2928 spa_log_error(spa, zio);
2929 zfs_ereport_post(FM_EREPORT_ZFS_DATA, spa, NULL, zio,
2930 0, 0);
2931 }
2932 }
2933
2934 if (zio->io_error && zio == lio) {
2935 /*
2936 * Determine whether zio should be reexecuted. This will
2937 * propagate all the way to the root via zio_notify_parent().
2938 */
2939 ASSERT(vd == NULL && bp != NULL);
2940 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
2941
2942 if (IO_IS_ALLOCATING(zio) &&
2943 !(zio->io_flags & ZIO_FLAG_CANFAIL)) {
2944 if (zio->io_error != ENOSPC)
2945 zio->io_reexecute |= ZIO_REEXECUTE_NOW;
2946 else
2947 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
2948 }
2949
2950 if ((zio->io_type == ZIO_TYPE_READ ||
2951 zio->io_type == ZIO_TYPE_FREE) &&
2952 !(zio->io_flags & ZIO_FLAG_SCAN_THREAD) &&
2953 zio->io_error == ENXIO &&
2954 spa_load_state(spa) == SPA_LOAD_NONE &&
2955 spa_get_failmode(spa) != ZIO_FAILURE_MODE_CONTINUE)
2956 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
2957
2958 if (!(zio->io_flags & ZIO_FLAG_CANFAIL) && !zio->io_reexecute)
2959 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
2960
2961 /*
2962 * Here is a possibly good place to attempt to do
2963 * either combinatorial reconstruction or error correction
2964 * based on checksums. It also might be a good place
2965 * to send out preliminary ereports before we suspend
2966 * processing.
2967 */
2968 }
2969
2970 /*
2971 * If there were logical child errors, they apply to us now.
2972 * We defer this until now to avoid conflating logical child
2973 * errors with errors that happened to the zio itself when
2974 * updating vdev stats and reporting FMA events above.
2975 */
2976 zio_inherit_child_errors(zio, ZIO_CHILD_LOGICAL);
2977
2978 if ((zio->io_error || zio->io_reexecute) &&
2979 IO_IS_ALLOCATING(zio) && zio->io_gang_leader == zio &&
2980 !(zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)))
2981 zio_dva_unallocate(zio, zio->io_gang_tree, bp);
2982
2983 zio_gang_tree_free(&zio->io_gang_tree);
2984
2985 /*
2986 * Godfather I/Os should never suspend.
2987 */
2988 if ((zio->io_flags & ZIO_FLAG_GODFATHER) &&
2989 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND))
2990 zio->io_reexecute = 0;
2991
2992 if (zio->io_reexecute) {
2993 /*
2994 * This is a logical I/O that wants to reexecute.
2995 *
2996 * Reexecute is top-down. When an i/o fails, if it's not
2997 * the root, it simply notifies its parent and sticks around.
2998 * The parent, seeing that it still has children in zio_done(),
2999 * does the same. This percolates all the way up to the root.
3000 * The root i/o will reexecute or suspend the entire tree.
3001 *
3002 * This approach ensures that zio_reexecute() honors
3003 * all the original i/o dependency relationships, e.g.
3004 * parents not executing until children are ready.
3005 */
3006 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
3007
3008 zio->io_gang_leader = NULL;
3009
3010 mutex_enter(&zio->io_lock);
3011 zio->io_state[ZIO_WAIT_DONE] = 1;
3012 mutex_exit(&zio->io_lock);
3013
3014 /*
3015 * "The Godfather" I/O monitors its children but is
3016 * not a true parent to them. It will track them through
3017 * the pipeline but severs its ties whenever they get into
3018 * trouble (e.g. suspended). This allows "The Godfather"
3019 * I/O to return status without blocking.
3020 */
3021 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) {
3022 zio_link_t *zl = zio->io_walk_link;
3023 pio_next = zio_walk_parents(zio);
3024
3025 if ((pio->io_flags & ZIO_FLAG_GODFATHER) &&
3026 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND)) {
3027 zio_remove_child(pio, zio, zl);
3028 zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
3029 }
3030 }
3031
3032 if ((pio = zio_unique_parent(zio)) != NULL) {
3033 /*
3034 * We're not a root i/o, so there's nothing to do
3035 * but notify our parent. Don't propagate errors
3036 * upward since we haven't permanently failed yet.
3037 */
3038 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER));
3039 zio->io_flags |= ZIO_FLAG_DONT_PROPAGATE;
3040 zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
3041 } else if (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND) {
3042 /*
3043 * We'd fail again if we reexecuted now, so suspend
3044 * until conditions improve (e.g. device comes online).
3045 */
3046 zio_suspend(spa, zio);
3047 } else {
3048 /*
3049 * Reexecution is potentially a huge amount of work.
3050 * Hand it off to the otherwise-unused claim taskq.
3051 */
3052 ASSERT(zio->io_tqent.tqent_next == NULL);
3053 spa_taskq_dispatch_ent(spa, ZIO_TYPE_CLAIM,
3054 ZIO_TASKQ_ISSUE, (task_func_t *)zio_reexecute, zio,
3055 0, &zio->io_tqent);
3056 }
3057 return (ZIO_PIPELINE_STOP);
3058 }
3059
3060 ASSERT(zio->io_child_count == 0);
3061 ASSERT(zio->io_reexecute == 0);
3062 ASSERT(zio->io_error == 0 || (zio->io_flags & ZIO_FLAG_CANFAIL));
3063
3064 /*
3065 * Report any checksum errors, since the I/O is complete.
3066 */
3067 while (zio->io_cksum_report != NULL) {
3068 zio_cksum_report_t *zcr = zio->io_cksum_report;
3069 zio->io_cksum_report = zcr->zcr_next;
3070 zcr->zcr_next = NULL;
3071 zcr->zcr_finish(zcr, NULL);
3072 zfs_ereport_free_checksum(zcr);
3073 }
3074
3075 /*
3076 * It is the responsibility of the done callback to ensure that this
3077 * particular zio is no longer discoverable for adoption, and as
3078 * such, cannot acquire any new parents.
3079 */
3080 if (zio->io_done)
3081 zio->io_done(zio);
3082
3083 mutex_enter(&zio->io_lock);
3084 zio->io_state[ZIO_WAIT_DONE] = 1;
3085 mutex_exit(&zio->io_lock);
3086
3087 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) {
3088 zio_link_t *zl = zio->io_walk_link;
3089 pio_next = zio_walk_parents(zio);
3090 zio_remove_child(pio, zio, zl);
3091 zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
3092 }
3093
3094 if (zio->io_waiter != NULL) {
3095 mutex_enter(&zio->io_lock);
3096 zio->io_executor = NULL;
3097 cv_broadcast(&zio->io_cv);
3098 mutex_exit(&zio->io_lock);
3099 } else {
3100 zio_destroy(zio);
3101 }
3102
3103 return (ZIO_PIPELINE_STOP);
3104 }
3105
3106 /*
3107 * ==========================================================================
3108 * I/O pipeline definition
3109 * ==========================================================================
3110 */
3111 static zio_pipe_stage_t *zio_pipeline[] = {
3112 NULL,
3113 zio_read_bp_init,
3114 zio_free_bp_init,
3115 zio_issue_async,
3116 zio_write_bp_init,
3117 zio_checksum_generate,
3118 zio_nop_write,
3119 zio_ddt_read_start,
3120 zio_ddt_read_done,
3121 zio_ddt_write,
3122 zio_ddt_free,
3123 zio_gang_assemble,
3124 zio_gang_issue,
3125 zio_dva_allocate,
3126 zio_dva_free,
3127 zio_dva_claim,
3128 zio_ready,
3129 zio_vdev_io_start,
3130 zio_vdev_io_done,
3131 zio_vdev_io_assess,
3132 zio_checksum_verify,
3133 zio_done
3134 };
3135
3136 /* dnp is the dnode for zb1->zb_object */
3137 boolean_t
3138 zbookmark_is_before(const dnode_phys_t *dnp, const zbookmark_t *zb1,
3139 const zbookmark_t *zb2)
3140 {
3141 uint64_t zb1nextL0, zb2thisobj;
3142
3143 ASSERT(zb1->zb_objset == zb2->zb_objset);
3144 ASSERT(zb2->zb_level == 0);
3145
3146 /*
3147 * A bookmark in the deadlist is considered to be after
3148 * everything else.
3149 */
3150 if (zb2->zb_object == DMU_DEADLIST_OBJECT)
3151 return (B_TRUE);
3152
3153 /* The objset_phys_t isn't before anything. */
3154 if (dnp == NULL)
3155 return (B_FALSE);
3156
3157 zb1nextL0 = (zb1->zb_blkid + 1) <<
3158 ((zb1->zb_level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT));
3159
3160 zb2thisobj = zb2->zb_object ? zb2->zb_object :
3161 zb2->zb_blkid << (DNODE_BLOCK_SHIFT - DNODE_SHIFT);
3162
3163 if (zb1->zb_object == DMU_META_DNODE_OBJECT) {
3164 uint64_t nextobj = zb1nextL0 *
3165 (dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT) >> DNODE_SHIFT;
3166 return (nextobj <= zb2thisobj);
3167 }
3168
3169 if (zb1->zb_object < zb2thisobj)
3170 return (B_TRUE);
3171 if (zb1->zb_object > zb2thisobj)
3172 return (B_FALSE);
3173 if (zb2->zb_object == DMU_META_DNODE_OBJECT)
3174 return (B_FALSE);
3175 return (zb1nextL0 <= zb2->zb_blkid);
3176 }