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