1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2011, 2014 by Delphix. All rights reserved.
24 * Copyright (c) 2011 Nexenta Systems, Inc. All rights reserved.
25 */
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 #include <sys/blkptr.h>
40 #include <sys/zfeature.h>
41
42 /*
43 * ==========================================================================
44 * I/O type descriptions
45 * ==========================================================================
46 */
47 const char *zio_type_name[ZIO_TYPES] = {
48 "zio_null", "zio_read", "zio_write", "zio_free", "zio_claim",
49 "zio_ioctl"
50 };
51
52 /*
53 * ==========================================================================
54 * I/O kmem caches
55 * ==========================================================================
56 */
57 kmem_cache_t *zio_cache;
58 kmem_cache_t *zio_link_cache;
59 kmem_cache_t *zio_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
60 kmem_cache_t *zio_data_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
61
62 #ifdef _KERNEL
63 extern vmem_t *zio_alloc_arena;
64 #endif
65
66 #define ZIO_PIPELINE_CONTINUE 0x100
67 #define ZIO_PIPELINE_STOP 0x101
68
69 /*
70 * The following actions directly effect the spa's sync-to-convergence logic.
71 * The values below define the sync pass when we start performing the action.
72 * Care should be taken when changing these values as they directly impact
73 * spa_sync() performance. Tuning these values may introduce subtle performance
74 * pathologies and should only be done in the context of performance analysis.
75 * These tunables will eventually be removed and replaced with #defines once
76 * enough analysis has been done to determine optimal values.
77 *
78 * The 'zfs_sync_pass_deferred_free' pass must be greater than 1 to ensure that
79 * regular blocks are not deferred.
80 */
81 int zfs_sync_pass_deferred_free = 2; /* defer frees starting in this pass */
82 int zfs_sync_pass_dont_compress = 5; /* don't compress starting in this pass */
83 int zfs_sync_pass_rewrite = 2; /* rewrite new bps starting in this pass */
84
85 /*
86 * An allocating zio is one that either currently has the DVA allocate
87 * stage set or will have it later in its lifetime.
88 */
89 #define IO_IS_ALLOCATING(zio) ((zio)->io_orig_pipeline & ZIO_STAGE_DVA_ALLOCATE)
90
91 boolean_t zio_requeue_io_start_cut_in_line = B_TRUE;
92
93 #ifdef ZFS_DEBUG
94 int zio_buf_debug_limit = 16384;
95 #else
96 int zio_buf_debug_limit = 0;
97 #endif
98
99 void
100 zio_init(void)
101 {
102 size_t c;
103 vmem_t *data_alloc_arena = NULL;
104
105 #ifdef _KERNEL
106 data_alloc_arena = zio_alloc_arena;
107 #endif
108 zio_cache = kmem_cache_create("zio_cache",
109 sizeof (zio_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
110 zio_link_cache = kmem_cache_create("zio_link_cache",
111 sizeof (zio_link_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
112
113 /*
114 * For small buffers, we want a cache for each multiple of
115 * SPA_MINBLOCKSIZE. For larger buffers, we want a cache
116 * for each quarter-power of 2.
117 */
118 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) {
119 size_t size = (c + 1) << SPA_MINBLOCKSHIFT;
120 size_t p2 = size;
121 size_t align = 0;
122 size_t cflags = (size > zio_buf_debug_limit) ? KMC_NODEBUG : 0;
123
124 while (p2 & (p2 - 1))
125 p2 &= p2 - 1;
126
127 #ifndef _KERNEL
128 /*
129 * If we are using watchpoints, put each buffer on its own page,
130 * to eliminate the performance overhead of trapping to the
131 * kernel when modifying a non-watched buffer that shares the
132 * page with a watched buffer.
133 */
134 if (arc_watch && !IS_P2ALIGNED(size, PAGESIZE))
135 continue;
136 #endif
137 if (size <= 4 * SPA_MINBLOCKSIZE) {
138 align = SPA_MINBLOCKSIZE;
139 } else if (IS_P2ALIGNED(size, p2 >> 2)) {
140 align = MIN(p2 >> 2, PAGESIZE);
141 }
142
143 if (align != 0) {
144 char name[36];
145 (void) sprintf(name, "zio_buf_%lu", (ulong_t)size);
146 zio_buf_cache[c] = kmem_cache_create(name, size,
147 align, NULL, NULL, NULL, NULL, NULL, cflags);
148
149 /*
150 * Since zio_data bufs do not appear in crash dumps, we
151 * pass KMC_NOTOUCH so that no allocator metadata is
152 * stored with the buffers.
153 */
154 (void) sprintf(name, "zio_data_buf_%lu", (ulong_t)size);
155 zio_data_buf_cache[c] = kmem_cache_create(name, size,
156 align, NULL, NULL, NULL, NULL, data_alloc_arena,
157 cflags | KMC_NOTOUCH);
158 }
159 }
160
161 while (--c != 0) {
162 ASSERT(zio_buf_cache[c] != NULL);
163 if (zio_buf_cache[c - 1] == NULL)
164 zio_buf_cache[c - 1] = zio_buf_cache[c];
165
166 ASSERT(zio_data_buf_cache[c] != NULL);
167 if (zio_data_buf_cache[c - 1] == NULL)
168 zio_data_buf_cache[c - 1] = zio_data_buf_cache[c];
169 }
170
171 zio_inject_init();
172 }
173
174 void
175 zio_fini(void)
176 {
177 size_t c;
178 kmem_cache_t *last_cache = NULL;
179 kmem_cache_t *last_data_cache = NULL;
180
181 for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) {
182 if (zio_buf_cache[c] != last_cache) {
183 last_cache = zio_buf_cache[c];
184 kmem_cache_destroy(zio_buf_cache[c]);
185 }
186 zio_buf_cache[c] = NULL;
187
188 if (zio_data_buf_cache[c] != last_data_cache) {
189 last_data_cache = zio_data_buf_cache[c];
190 kmem_cache_destroy(zio_data_buf_cache[c]);
191 }
192 zio_data_buf_cache[c] = NULL;
193 }
194
195 kmem_cache_destroy(zio_link_cache);
196 kmem_cache_destroy(zio_cache);
197
198 zio_inject_fini();
199 }
200
201 /*
202 * ==========================================================================
203 * Allocate and free I/O buffers
204 * ==========================================================================
205 */
206
207 /*
208 * Use zio_buf_alloc to allocate ZFS metadata. This data will appear in a
209 * crashdump if the kernel panics, so use it judiciously. Obviously, it's
210 * useful to inspect ZFS metadata, but if possible, we should avoid keeping
211 * excess / transient data in-core during a crashdump.
212 */
213 void *
214 zio_buf_alloc(size_t size)
215 {
216 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
217
218 ASSERT3U(c, <, SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
219
220 return (kmem_cache_alloc(zio_buf_cache[c], KM_PUSHPAGE));
221 }
222
223 /*
224 * Use zio_data_buf_alloc to allocate data. The data will not appear in a
225 * crashdump if the kernel panics. This exists so that we will limit the amount
226 * of ZFS data that shows up in a kernel crashdump. (Thus reducing the amount
227 * of kernel heap dumped to disk when the kernel panics)
228 */
229 void *
230 zio_data_buf_alloc(size_t size)
231 {
232 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
233
234 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
235
236 return (kmem_cache_alloc(zio_data_buf_cache[c], KM_PUSHPAGE));
237 }
238
239 void
240 zio_buf_free(void *buf, size_t size)
241 {
242 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
243
244 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
245
246 kmem_cache_free(zio_buf_cache[c], buf);
247 }
248
249 void
250 zio_data_buf_free(void *buf, size_t size)
251 {
252 size_t c = (size - 1) >> SPA_MINBLOCKSHIFT;
253
254 ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT);
255
256 kmem_cache_free(zio_data_buf_cache[c], buf);
257 }
258
259 /*
260 * ==========================================================================
261 * Push and pop I/O transform buffers
262 * ==========================================================================
263 */
264 static void
265 zio_push_transform(zio_t *zio, void *data, uint64_t size, uint64_t bufsize,
266 zio_transform_func_t *transform)
267 {
268 zio_transform_t *zt = kmem_alloc(sizeof (zio_transform_t), KM_SLEEP);
269
270 zt->zt_orig_data = zio->io_data;
271 zt->zt_orig_size = zio->io_size;
272 zt->zt_bufsize = bufsize;
273 zt->zt_transform = transform;
274
275 zt->zt_next = zio->io_transform_stack;
276 zio->io_transform_stack = zt;
277
278 zio->io_data = data;
279 zio->io_size = size;
280 }
281
282 static void
283 zio_pop_transforms(zio_t *zio)
284 {
285 zio_transform_t *zt;
286
287 while ((zt = zio->io_transform_stack) != NULL) {
288 if (zt->zt_transform != NULL)
289 zt->zt_transform(zio,
290 zt->zt_orig_data, zt->zt_orig_size);
291
292 if (zt->zt_bufsize != 0)
293 zio_buf_free(zio->io_data, zt->zt_bufsize);
294
295 zio->io_data = zt->zt_orig_data;
296 zio->io_size = zt->zt_orig_size;
297 zio->io_transform_stack = zt->zt_next;
298
299 kmem_free(zt, sizeof (zio_transform_t));
300 }
301 }
302
303 /*
304 * ==========================================================================
305 * I/O transform callbacks for subblocks and decompression
306 * ==========================================================================
307 */
308 static void
309 zio_subblock(zio_t *zio, void *data, uint64_t size)
310 {
311 ASSERT(zio->io_size > size);
312
313 if (zio->io_type == ZIO_TYPE_READ)
314 bcopy(zio->io_data, data, size);
315 }
316
317 static void
318 zio_decompress(zio_t *zio, void *data, uint64_t size)
319 {
320 if (zio->io_error == 0 &&
321 zio_decompress_data(BP_GET_COMPRESS(zio->io_bp),
322 zio->io_data, data, zio->io_size, size) != 0)
323 zio->io_error = SET_ERROR(EIO);
324 }
325
326 /*
327 * ==========================================================================
328 * I/O parent/child relationships and pipeline interlocks
329 * ==========================================================================
330 */
331 /*
332 * NOTE - Callers to zio_walk_parents() and zio_walk_children must
333 * continue calling these functions until they return NULL.
334 * Otherwise, the next caller will pick up the list walk in
335 * some indeterminate state. (Otherwise every caller would
336 * have to pass in a cookie to keep the state represented by
337 * io_walk_link, which gets annoying.)
338 */
339 zio_t *
340 zio_walk_parents(zio_t *cio)
341 {
342 zio_link_t *zl = cio->io_walk_link;
343 list_t *pl = &cio->io_parent_list;
344
345 zl = (zl == NULL) ? list_head(pl) : list_next(pl, zl);
346 cio->io_walk_link = zl;
347
348 if (zl == NULL)
349 return (NULL);
350
351 ASSERT(zl->zl_child == cio);
352 return (zl->zl_parent);
353 }
354
355 zio_t *
356 zio_walk_children(zio_t *pio)
357 {
358 zio_link_t *zl = pio->io_walk_link;
359 list_t *cl = &pio->io_child_list;
360
361 zl = (zl == NULL) ? list_head(cl) : list_next(cl, zl);
362 pio->io_walk_link = zl;
363
364 if (zl == NULL)
365 return (NULL);
366
367 ASSERT(zl->zl_parent == pio);
368 return (zl->zl_child);
369 }
370
371 zio_t *
372 zio_unique_parent(zio_t *cio)
373 {
374 zio_t *pio = zio_walk_parents(cio);
375
376 VERIFY(zio_walk_parents(cio) == NULL);
377 return (pio);
378 }
379
380 void
381 zio_add_child(zio_t *pio, zio_t *cio)
382 {
383 zio_link_t *zl = kmem_cache_alloc(zio_link_cache, KM_SLEEP);
384
385 /*
386 * Logical I/Os can have logical, gang, or vdev children.
387 * Gang I/Os can have gang or vdev children.
388 * Vdev I/Os can only have vdev children.
389 * The following ASSERT captures all of these constraints.
390 */
391 ASSERT(cio->io_child_type <= pio->io_child_type);
392
393 zl->zl_parent = pio;
394 zl->zl_child = cio;
395
396 mutex_enter(&cio->io_lock);
397 mutex_enter(&pio->io_lock);
398
399 ASSERT(pio->io_state[ZIO_WAIT_DONE] == 0);
400
401 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
402 pio->io_children[cio->io_child_type][w] += !cio->io_state[w];
403
404 list_insert_head(&pio->io_child_list, zl);
405 list_insert_head(&cio->io_parent_list, zl);
406
407 pio->io_child_count++;
408 cio->io_parent_count++;
409
410 mutex_exit(&pio->io_lock);
411 mutex_exit(&cio->io_lock);
412 }
413
414 static void
415 zio_remove_child(zio_t *pio, zio_t *cio, zio_link_t *zl)
416 {
417 ASSERT(zl->zl_parent == pio);
418 ASSERT(zl->zl_child == cio);
419
420 mutex_enter(&cio->io_lock);
421 mutex_enter(&pio->io_lock);
422
423 list_remove(&pio->io_child_list, zl);
424 list_remove(&cio->io_parent_list, zl);
425
426 pio->io_child_count--;
427 cio->io_parent_count--;
428
429 mutex_exit(&pio->io_lock);
430 mutex_exit(&cio->io_lock);
431
432 kmem_cache_free(zio_link_cache, zl);
433 }
434
435 static boolean_t
436 zio_wait_for_children(zio_t *zio, enum zio_child child, enum zio_wait_type wait)
437 {
438 uint64_t *countp = &zio->io_children[child][wait];
439 boolean_t waiting = B_FALSE;
440
441 mutex_enter(&zio->io_lock);
442 ASSERT(zio->io_stall == NULL);
443 if (*countp != 0) {
444 zio->io_stage >>= 1;
445 zio->io_stall = countp;
446 waiting = B_TRUE;
447 }
448 mutex_exit(&zio->io_lock);
449
450 return (waiting);
451 }
452
453 static void
454 zio_notify_parent(zio_t *pio, zio_t *zio, enum zio_wait_type wait)
455 {
456 uint64_t *countp = &pio->io_children[zio->io_child_type][wait];
457 int *errorp = &pio->io_child_error[zio->io_child_type];
458
459 mutex_enter(&pio->io_lock);
460 if (zio->io_error && !(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE))
461 *errorp = zio_worst_error(*errorp, zio->io_error);
462 pio->io_reexecute |= zio->io_reexecute;
463 ASSERT3U(*countp, >, 0);
464
465 (*countp)--;
466
467 if (*countp == 0 && pio->io_stall == countp) {
468 pio->io_stall = NULL;
469 mutex_exit(&pio->io_lock);
470 zio_execute(pio);
471 } else {
472 mutex_exit(&pio->io_lock);
473 }
474 }
475
476 static void
477 zio_inherit_child_errors(zio_t *zio, enum zio_child c)
478 {
479 if (zio->io_child_error[c] != 0 && zio->io_error == 0)
480 zio->io_error = zio->io_child_error[c];
481 }
482
483 /*
484 * ==========================================================================
485 * Create the various types of I/O (read, write, free, etc)
486 * ==========================================================================
487 */
488 static zio_t *
489 zio_create(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
490 void *data, uint64_t size, zio_done_func_t *done, void *private,
491 zio_type_t type, zio_priority_t priority, enum zio_flag flags,
492 vdev_t *vd, uint64_t offset, const zbookmark_phys_t *zb,
493 enum zio_stage stage, enum zio_stage pipeline)
494 {
495 zio_t *zio;
496
497 ASSERT3U(size, <=, SPA_MAXBLOCKSIZE);
498 ASSERT(P2PHASE(size, SPA_MINBLOCKSIZE) == 0);
499 ASSERT(P2PHASE(offset, SPA_MINBLOCKSIZE) == 0);
500
501 ASSERT(!vd || spa_config_held(spa, SCL_STATE_ALL, RW_READER));
502 ASSERT(!bp || !(flags & ZIO_FLAG_CONFIG_WRITER));
503 ASSERT(vd || stage == ZIO_STAGE_OPEN);
504
505 zio = kmem_cache_alloc(zio_cache, KM_SLEEP);
506 bzero(zio, sizeof (zio_t));
507
508 mutex_init(&zio->io_lock, NULL, MUTEX_DEFAULT, NULL);
509 cv_init(&zio->io_cv, NULL, CV_DEFAULT, NULL);
510
511 list_create(&zio->io_parent_list, sizeof (zio_link_t),
512 offsetof(zio_link_t, zl_parent_node));
513 list_create(&zio->io_child_list, sizeof (zio_link_t),
514 offsetof(zio_link_t, zl_child_node));
515
516 if (vd != NULL)
517 zio->io_child_type = ZIO_CHILD_VDEV;
518 else if (flags & ZIO_FLAG_GANG_CHILD)
519 zio->io_child_type = ZIO_CHILD_GANG;
520 else if (flags & ZIO_FLAG_DDT_CHILD)
521 zio->io_child_type = ZIO_CHILD_DDT;
522 else
523 zio->io_child_type = ZIO_CHILD_LOGICAL;
524
525 if (bp != NULL) {
526 zio->io_bp = (blkptr_t *)bp;
527 zio->io_bp_copy = *bp;
528 zio->io_bp_orig = *bp;
529 if (type != ZIO_TYPE_WRITE ||
530 zio->io_child_type == ZIO_CHILD_DDT)
531 zio->io_bp = &zio->io_bp_copy; /* so caller can free */
532 if (zio->io_child_type == ZIO_CHILD_LOGICAL)
533 zio->io_logical = zio;
534 if (zio->io_child_type > ZIO_CHILD_GANG && BP_IS_GANG(bp))
535 pipeline |= ZIO_GANG_STAGES;
536 }
537
538 zio->io_spa = spa;
539 zio->io_txg = txg;
540 zio->io_done = done;
541 zio->io_private = private;
542 zio->io_type = type;
543 zio->io_priority = priority;
544 zio->io_vd = vd;
545 zio->io_offset = offset;
546 zio->io_orig_data = zio->io_data = data;
547 zio->io_orig_size = zio->io_size = size;
548 zio->io_orig_flags = zio->io_flags = flags;
549 zio->io_orig_stage = zio->io_stage = stage;
550 zio->io_orig_pipeline = zio->io_pipeline = pipeline;
551
552 zio->io_state[ZIO_WAIT_READY] = (stage >= ZIO_STAGE_READY);
553 zio->io_state[ZIO_WAIT_DONE] = (stage >= ZIO_STAGE_DONE);
554
555 if (zb != NULL)
556 zio->io_bookmark = *zb;
557
558 if (pio != NULL) {
559 if (zio->io_logical == NULL)
560 zio->io_logical = pio->io_logical;
561 if (zio->io_child_type == ZIO_CHILD_GANG)
562 zio->io_gang_leader = pio->io_gang_leader;
563 zio_add_child(pio, zio);
564 }
565
566 return (zio);
567 }
568
569 static void
570 zio_destroy(zio_t *zio)
571 {
572 list_destroy(&zio->io_parent_list);
573 list_destroy(&zio->io_child_list);
574 mutex_destroy(&zio->io_lock);
575 cv_destroy(&zio->io_cv);
576 kmem_cache_free(zio_cache, zio);
577 }
578
579 zio_t *
580 zio_null(zio_t *pio, spa_t *spa, vdev_t *vd, zio_done_func_t *done,
581 void *private, enum zio_flag flags)
582 {
583 zio_t *zio;
584
585 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private,
586 ZIO_TYPE_NULL, ZIO_PRIORITY_NOW, flags, vd, 0, NULL,
587 ZIO_STAGE_OPEN, ZIO_INTERLOCK_PIPELINE);
588
589 return (zio);
590 }
591
592 zio_t *
593 zio_root(spa_t *spa, zio_done_func_t *done, void *private, enum zio_flag flags)
594 {
595 return (zio_null(NULL, spa, NULL, done, private, flags));
596 }
597
598 zio_t *
599 zio_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
600 void *data, uint64_t size, zio_done_func_t *done, void *private,
601 zio_priority_t priority, enum zio_flag flags, const zbookmark_phys_t *zb)
602 {
603 zio_t *zio;
604
605 zio = zio_create(pio, spa, BP_PHYSICAL_BIRTH(bp), bp,
606 data, size, done, private,
607 ZIO_TYPE_READ, priority, flags, NULL, 0, zb,
608 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ?
609 ZIO_DDT_CHILD_READ_PIPELINE : ZIO_READ_PIPELINE);
610
611 return (zio);
612 }
613
614 zio_t *
615 zio_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
616 void *data, uint64_t size, const zio_prop_t *zp,
617 zio_done_func_t *ready, zio_done_func_t *physdone, zio_done_func_t *done,
618 void *private,
619 zio_priority_t priority, enum zio_flag flags, const zbookmark_phys_t *zb)
620 {
621 zio_t *zio;
622
623 ASSERT(zp->zp_checksum >= ZIO_CHECKSUM_OFF &&
624 zp->zp_checksum < ZIO_CHECKSUM_FUNCTIONS &&
625 zp->zp_compress >= ZIO_COMPRESS_OFF &&
626 zp->zp_compress < ZIO_COMPRESS_FUNCTIONS &&
627 DMU_OT_IS_VALID(zp->zp_type) &&
628 zp->zp_level < 32 &&
629 zp->zp_copies > 0 &&
630 zp->zp_copies <= spa_max_replication(spa));
631
632 zio = zio_create(pio, spa, txg, bp, data, size, done, private,
633 ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb,
634 ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ?
635 ZIO_DDT_CHILD_WRITE_PIPELINE : ZIO_WRITE_PIPELINE);
636
637 zio->io_ready = ready;
638 zio->io_physdone = physdone;
639 zio->io_prop = *zp;
640
641 /*
642 * Data can be NULL if we are going to call zio_write_override() to
643 * provide the already-allocated BP. But we may need the data to
644 * verify a dedup hit (if requested). In this case, don't try to
645 * dedup (just take the already-allocated BP verbatim).
646 */
647 if (data == NULL && zio->io_prop.zp_dedup_verify) {
648 zio->io_prop.zp_dedup = zio->io_prop.zp_dedup_verify = B_FALSE;
649 }
650
651 return (zio);
652 }
653
654 zio_t *
655 zio_rewrite(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, void *data,
656 uint64_t size, zio_done_func_t *done, void *private,
657 zio_priority_t priority, enum zio_flag flags, zbookmark_phys_t *zb)
658 {
659 zio_t *zio;
660
661 zio = zio_create(pio, spa, txg, bp, data, size, done, private,
662 ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb,
663 ZIO_STAGE_OPEN, ZIO_REWRITE_PIPELINE);
664
665 return (zio);
666 }
667
668 void
669 zio_write_override(zio_t *zio, blkptr_t *bp, int copies, boolean_t nopwrite)
670 {
671 ASSERT(zio->io_type == ZIO_TYPE_WRITE);
672 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
673 ASSERT(zio->io_stage == ZIO_STAGE_OPEN);
674 ASSERT(zio->io_txg == spa_syncing_txg(zio->io_spa));
675
676 /*
677 * We must reset the io_prop to match the values that existed
678 * when the bp was first written by dmu_sync() keeping in mind
679 * that nopwrite and dedup are mutually exclusive.
680 */
681 zio->io_prop.zp_dedup = nopwrite ? B_FALSE : zio->io_prop.zp_dedup;
682 zio->io_prop.zp_nopwrite = nopwrite;
683 zio->io_prop.zp_copies = copies;
684 zio->io_bp_override = bp;
685 }
686
687 void
688 zio_free(spa_t *spa, uint64_t txg, const blkptr_t *bp)
689 {
690
691 /*
692 * The check for EMBEDDED is a performance optimization. We
693 * process the free here (by ignoring it) rather than
694 * putting it on the list and then processing it in zio_free_sync().
695 */
696 if (BP_IS_EMBEDDED(bp))
697 return;
698 metaslab_check_free(spa, bp);
699
700 /*
701 * Frees that are for the currently-syncing txg, are not going to be
702 * deferred, and which will not need to do a read (i.e. not GANG or
703 * DEDUP), can be processed immediately. Otherwise, put them on the
704 * in-memory list for later processing.
705 */
706 if (BP_IS_GANG(bp) || BP_GET_DEDUP(bp) ||
707 txg != spa->spa_syncing_txg ||
708 spa_sync_pass(spa) >= zfs_sync_pass_deferred_free) {
709 bplist_append(&spa->spa_free_bplist[txg & TXG_MASK], bp);
710 } else {
711 VERIFY0(zio_wait(zio_free_sync(NULL, spa, txg, bp, 0)));
712 }
713 }
714
715 zio_t *
716 zio_free_sync(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
717 enum zio_flag flags)
718 {
719 zio_t *zio;
720 enum zio_stage stage = ZIO_FREE_PIPELINE;
721
722 ASSERT(!BP_IS_HOLE(bp));
723 ASSERT(spa_syncing_txg(spa) == txg);
724 ASSERT(spa_sync_pass(spa) < zfs_sync_pass_deferred_free);
725
726 if (BP_IS_EMBEDDED(bp))
727 return (zio_null(pio, spa, NULL, NULL, NULL, 0));
728
729 metaslab_check_free(spa, bp);
730 arc_freed(spa, bp);
731
732 /*
733 * GANG and DEDUP blocks can induce a read (for the gang block header,
734 * or the DDT), so issue them asynchronously so that this thread is
735 * not tied up.
736 */
737 if (BP_IS_GANG(bp) || BP_GET_DEDUP(bp))
738 stage |= ZIO_STAGE_ISSUE_ASYNC;
739
740 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp),
741 NULL, NULL, ZIO_TYPE_FREE, ZIO_PRIORITY_NOW, flags,
742 NULL, 0, NULL, ZIO_STAGE_OPEN, stage);
743
744 return (zio);
745 }
746
747 zio_t *
748 zio_claim(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
749 zio_done_func_t *done, void *private, enum zio_flag flags)
750 {
751 zio_t *zio;
752
753 dprintf_bp(bp, "claiming in txg %llu", txg);
754
755 if (BP_IS_EMBEDDED(bp))
756 return (zio_null(pio, spa, NULL, NULL, NULL, 0));
757
758 /*
759 * A claim is an allocation of a specific block. Claims are needed
760 * to support immediate writes in the intent log. The issue is that
761 * immediate writes contain committed data, but in a txg that was
762 * *not* committed. Upon opening the pool after an unclean shutdown,
763 * the intent log claims all blocks that contain immediate write data
764 * so that the SPA knows they're in use.
765 *
766 * All claims *must* be resolved in the first txg -- before the SPA
767 * starts allocating blocks -- so that nothing is allocated twice.
768 * If txg == 0 we just verify that the block is claimable.
769 */
770 ASSERT3U(spa->spa_uberblock.ub_rootbp.blk_birth, <, spa_first_txg(spa));
771 ASSERT(txg == spa_first_txg(spa) || txg == 0);
772 ASSERT(!BP_GET_DEDUP(bp) || !spa_writeable(spa)); /* zdb(1M) */
773
774 zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp),
775 done, private, ZIO_TYPE_CLAIM, ZIO_PRIORITY_NOW, flags,
776 NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_CLAIM_PIPELINE);
777
778 return (zio);
779 }
780
781 zio_t *
782 zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd,
783 zio_done_func_t *done, void *private, enum zio_flag flags)
784 {
785 zio_t *zio;
786 int c;
787
788 if (vd->vdev_children == 0) {
789 zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private,
790 ZIO_TYPE_IOCTL, ZIO_PRIORITY_NOW, flags, vd, 0, NULL,
791 ZIO_STAGE_OPEN, ZIO_IOCTL_PIPELINE);
792
793 zio->io_cmd = cmd;
794 } else {
795 zio = zio_null(pio, spa, NULL, NULL, NULL, flags);
796
797 for (c = 0; c < vd->vdev_children; c++)
798 zio_nowait(zio_ioctl(zio, spa, vd->vdev_child[c], cmd,
799 done, private, flags));
800 }
801
802 return (zio);
803 }
804
805 zio_t *
806 zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size,
807 void *data, int checksum, zio_done_func_t *done, void *private,
808 zio_priority_t priority, enum zio_flag flags, boolean_t labels)
809 {
810 zio_t *zio;
811
812 ASSERT(vd->vdev_children == 0);
813 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE ||
814 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE);
815 ASSERT3U(offset + size, <=, vd->vdev_psize);
816
817 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private,
818 ZIO_TYPE_READ, priority, flags | ZIO_FLAG_PHYSICAL, vd, offset,
819 NULL, ZIO_STAGE_OPEN, ZIO_READ_PHYS_PIPELINE);
820
821 zio->io_prop.zp_checksum = checksum;
822
823 return (zio);
824 }
825
826 zio_t *
827 zio_write_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size,
828 void *data, int checksum, zio_done_func_t *done, void *private,
829 zio_priority_t priority, enum zio_flag flags, boolean_t labels)
830 {
831 zio_t *zio;
832
833 ASSERT(vd->vdev_children == 0);
834 ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE ||
835 offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE);
836 ASSERT3U(offset + size, <=, vd->vdev_psize);
837
838 zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private,
839 ZIO_TYPE_WRITE, priority, flags | ZIO_FLAG_PHYSICAL, vd, offset,
840 NULL, ZIO_STAGE_OPEN, ZIO_WRITE_PHYS_PIPELINE);
841
842 zio->io_prop.zp_checksum = checksum;
843
844 if (zio_checksum_table[checksum].ci_eck) {
845 /*
846 * zec checksums are necessarily destructive -- they modify
847 * the end of the write buffer to hold the verifier/checksum.
848 * Therefore, we must make a local copy in case the data is
849 * being written to multiple places in parallel.
850 */
851 void *wbuf = zio_buf_alloc(size);
852 bcopy(data, wbuf, size);
853 zio_push_transform(zio, wbuf, size, size, NULL);
854 }
855
856 return (zio);
857 }
858
859 /*
860 * Create a child I/O to do some work for us.
861 */
862 zio_t *
863 zio_vdev_child_io(zio_t *pio, blkptr_t *bp, vdev_t *vd, uint64_t offset,
864 void *data, uint64_t size, int type, zio_priority_t priority,
865 enum zio_flag flags, zio_done_func_t *done, void *private)
866 {
867 enum zio_stage pipeline = ZIO_VDEV_CHILD_PIPELINE;
868 zio_t *zio;
869
870 ASSERT(vd->vdev_parent ==
871 (pio->io_vd ? pio->io_vd : pio->io_spa->spa_root_vdev));
872
873 if (type == ZIO_TYPE_READ && bp != NULL) {
874 /*
875 * If we have the bp, then the child should perform the
876 * checksum and the parent need not. This pushes error
877 * detection as close to the leaves as possible and
878 * eliminates redundant checksums in the interior nodes.
879 */
880 pipeline |= ZIO_STAGE_CHECKSUM_VERIFY;
881 pio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY;
882 }
883
884 if (vd->vdev_children == 0)
885 offset += VDEV_LABEL_START_SIZE;
886
887 flags |= ZIO_VDEV_CHILD_FLAGS(pio) | ZIO_FLAG_DONT_PROPAGATE;
888
889 /*
890 * If we've decided to do a repair, the write is not speculative --
891 * even if the original read was.
892 */
893 if (flags & ZIO_FLAG_IO_REPAIR)
894 flags &= ~ZIO_FLAG_SPECULATIVE;
895
896 zio = zio_create(pio, pio->io_spa, pio->io_txg, bp, data, size,
897 done, private, type, priority, flags, vd, offset, &pio->io_bookmark,
898 ZIO_STAGE_VDEV_IO_START >> 1, pipeline);
899
900 zio->io_physdone = pio->io_physdone;
901 if (vd->vdev_ops->vdev_op_leaf && zio->io_logical != NULL)
902 zio->io_logical->io_phys_children++;
903
904 return (zio);
905 }
906
907 zio_t *
908 zio_vdev_delegated_io(vdev_t *vd, uint64_t offset, void *data, uint64_t size,
909 int type, zio_priority_t priority, enum zio_flag flags,
910 zio_done_func_t *done, void *private)
911 {
912 zio_t *zio;
913
914 ASSERT(vd->vdev_ops->vdev_op_leaf);
915
916 zio = zio_create(NULL, vd->vdev_spa, 0, NULL,
917 data, size, done, private, type, priority,
918 flags | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_RETRY | ZIO_FLAG_DELEGATED,
919 vd, offset, NULL,
920 ZIO_STAGE_VDEV_IO_START >> 1, ZIO_VDEV_CHILD_PIPELINE);
921
922 return (zio);
923 }
924
925 void
926 zio_flush(zio_t *zio, vdev_t *vd)
927 {
928 zio_nowait(zio_ioctl(zio, zio->io_spa, vd, DKIOCFLUSHWRITECACHE,
929 NULL, NULL,
930 ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY));
931 }
932
933 void
934 zio_shrink(zio_t *zio, uint64_t size)
935 {
936 ASSERT(zio->io_executor == NULL);
937 ASSERT(zio->io_orig_size == zio->io_size);
938 ASSERT(size <= zio->io_size);
939
940 /*
941 * We don't shrink for raidz because of problems with the
942 * reconstruction when reading back less than the block size.
943 * Note, BP_IS_RAIDZ() assumes no compression.
944 */
945 ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF);
946 if (!BP_IS_RAIDZ(zio->io_bp))
947 zio->io_orig_size = zio->io_size = size;
948 }
949
950 /*
951 * ==========================================================================
952 * Prepare to read and write logical blocks
953 * ==========================================================================
954 */
955
956 static int
957 zio_read_bp_init(zio_t *zio)
958 {
959 blkptr_t *bp = zio->io_bp;
960
961 if (BP_GET_COMPRESS(bp) != ZIO_COMPRESS_OFF &&
962 zio->io_child_type == ZIO_CHILD_LOGICAL &&
963 !(zio->io_flags & ZIO_FLAG_RAW)) {
964 uint64_t psize =
965 BP_IS_EMBEDDED(bp) ? BPE_GET_PSIZE(bp) : BP_GET_PSIZE(bp);
966 void *cbuf = zio_buf_alloc(psize);
967
968 zio_push_transform(zio, cbuf, psize, psize, zio_decompress);
969 }
970
971 if (BP_IS_EMBEDDED(bp) && BPE_GET_ETYPE(bp) == BP_EMBEDDED_TYPE_DATA) {
972 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
973 decode_embedded_bp_compressed(bp, zio->io_data);
974 } else {
975 ASSERT(!BP_IS_EMBEDDED(bp));
976 }
977
978 if (!DMU_OT_IS_METADATA(BP_GET_TYPE(bp)) && BP_GET_LEVEL(bp) == 0)
979 zio->io_flags |= ZIO_FLAG_DONT_CACHE;
980
981 if (BP_GET_TYPE(bp) == DMU_OT_DDT_ZAP)
982 zio->io_flags |= ZIO_FLAG_DONT_CACHE;
983
984 if (BP_GET_DEDUP(bp) && zio->io_child_type == ZIO_CHILD_LOGICAL)
985 zio->io_pipeline = ZIO_DDT_READ_PIPELINE;
986
987 return (ZIO_PIPELINE_CONTINUE);
988 }
989
990 static int
991 zio_write_bp_init(zio_t *zio)
992 {
993 spa_t *spa = zio->io_spa;
994 zio_prop_t *zp = &zio->io_prop;
995 enum zio_compress compress = zp->zp_compress;
996 blkptr_t *bp = zio->io_bp;
997 uint64_t lsize = zio->io_size;
998 uint64_t psize = lsize;
999 int pass = 1;
1000
1001 /*
1002 * If our children haven't all reached the ready stage,
1003 * wait for them and then repeat this pipeline stage.
1004 */
1005 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) ||
1006 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_READY))
1007 return (ZIO_PIPELINE_STOP);
1008
1009 if (!IO_IS_ALLOCATING(zio))
1010 return (ZIO_PIPELINE_CONTINUE);
1011
1012 ASSERT(zio->io_child_type != ZIO_CHILD_DDT);
1013
1014 if (zio->io_bp_override) {
1015 ASSERT(bp->blk_birth != zio->io_txg);
1016 ASSERT(BP_GET_DEDUP(zio->io_bp_override) == 0);
1017
1018 *bp = *zio->io_bp_override;
1019 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1020
1021 if (BP_IS_EMBEDDED(bp))
1022 return (ZIO_PIPELINE_CONTINUE);
1023
1024 /*
1025 * If we've been overridden and nopwrite is set then
1026 * set the flag accordingly to indicate that a nopwrite
1027 * has already occurred.
1028 */
1029 if (!BP_IS_HOLE(bp) && zp->zp_nopwrite) {
1030 ASSERT(!zp->zp_dedup);
1031 zio->io_flags |= ZIO_FLAG_NOPWRITE;
1032 return (ZIO_PIPELINE_CONTINUE);
1033 }
1034
1035 ASSERT(!zp->zp_nopwrite);
1036
1037 if (BP_IS_HOLE(bp) || !zp->zp_dedup)
1038 return (ZIO_PIPELINE_CONTINUE);
1039
1040 ASSERT(zio_checksum_table[zp->zp_checksum].ci_dedup ||
1041 zp->zp_dedup_verify);
1042
1043 if (BP_GET_CHECKSUM(bp) == zp->zp_checksum) {
1044 BP_SET_DEDUP(bp, 1);
1045 zio->io_pipeline |= ZIO_STAGE_DDT_WRITE;
1046 return (ZIO_PIPELINE_CONTINUE);
1047 }
1048 zio->io_bp_override = NULL;
1049 BP_ZERO(bp);
1050 }
1051
1052 if (!BP_IS_HOLE(bp) && bp->blk_birth == zio->io_txg) {
1053 /*
1054 * We're rewriting an existing block, which means we're
1055 * working on behalf of spa_sync(). For spa_sync() to
1056 * converge, it must eventually be the case that we don't
1057 * have to allocate new blocks. But compression changes
1058 * the blocksize, which forces a reallocate, and makes
1059 * convergence take longer. Therefore, after the first
1060 * few passes, stop compressing to ensure convergence.
1061 */
1062 pass = spa_sync_pass(spa);
1063
1064 ASSERT(zio->io_txg == spa_syncing_txg(spa));
1065 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1066 ASSERT(!BP_GET_DEDUP(bp));
1067
1068 if (pass >= zfs_sync_pass_dont_compress)
1069 compress = ZIO_COMPRESS_OFF;
1070
1071 /* Make sure someone doesn't change their mind on overwrites */
1072 ASSERT(BP_IS_EMBEDDED(bp) || MIN(zp->zp_copies + BP_IS_GANG(bp),
1073 spa_max_replication(spa)) == BP_GET_NDVAS(bp));
1074 }
1075
1076 if (compress != ZIO_COMPRESS_OFF) {
1077 void *cbuf = zio_buf_alloc(lsize);
1078 psize = zio_compress_data(compress, zio->io_data, cbuf, lsize);
1079 if (psize == 0 || psize == lsize) {
1080 compress = ZIO_COMPRESS_OFF;
1081 zio_buf_free(cbuf, lsize);
1082 } else if (!zp->zp_dedup && psize <= BPE_PAYLOAD_SIZE &&
1083 zp->zp_level == 0 && !DMU_OT_HAS_FILL(zp->zp_type) &&
1084 spa_feature_is_enabled(spa, SPA_FEATURE_EMBEDDED_DATA)) {
1085 encode_embedded_bp_compressed(bp,
1086 cbuf, compress, lsize, psize);
1087 BPE_SET_ETYPE(bp, BP_EMBEDDED_TYPE_DATA);
1088 BP_SET_TYPE(bp, zio->io_prop.zp_type);
1089 BP_SET_LEVEL(bp, zio->io_prop.zp_level);
1090 zio_buf_free(cbuf, lsize);
1091 bp->blk_birth = zio->io_txg;
1092 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1093 ASSERT(spa_feature_is_active(spa,
1094 SPA_FEATURE_EMBEDDED_DATA));
1095 return (ZIO_PIPELINE_CONTINUE);
1096 } else {
1097 /*
1098 * Round up compressed size to MINBLOCKSIZE and
1099 * zero the tail.
1100 */
1101 size_t rounded =
1102 P2ROUNDUP(psize, (size_t)SPA_MINBLOCKSIZE);
1103 if (rounded > psize) {
1104 bzero((char *)cbuf + psize, rounded - psize);
1105 psize = rounded;
1106 }
1107 if (psize == lsize) {
1108 compress = ZIO_COMPRESS_OFF;
1109 zio_buf_free(cbuf, lsize);
1110 } else {
1111 zio_push_transform(zio, cbuf,
1112 psize, lsize, NULL);
1113 }
1114 }
1115 }
1116
1117 /*
1118 * The final pass of spa_sync() must be all rewrites, but the first
1119 * few passes offer a trade-off: allocating blocks defers convergence,
1120 * but newly allocated blocks are sequential, so they can be written
1121 * to disk faster. Therefore, we allow the first few passes of
1122 * spa_sync() to allocate new blocks, but force rewrites after that.
1123 * There should only be a handful of blocks after pass 1 in any case.
1124 */
1125 if (!BP_IS_HOLE(bp) && bp->blk_birth == zio->io_txg &&
1126 BP_GET_PSIZE(bp) == psize &&
1127 pass >= zfs_sync_pass_rewrite) {
1128 ASSERT(psize != 0);
1129 enum zio_stage gang_stages = zio->io_pipeline & ZIO_GANG_STAGES;
1130 zio->io_pipeline = ZIO_REWRITE_PIPELINE | gang_stages;
1131 zio->io_flags |= ZIO_FLAG_IO_REWRITE;
1132 } else {
1133 BP_ZERO(bp);
1134 zio->io_pipeline = ZIO_WRITE_PIPELINE;
1135 }
1136
1137 if (psize == 0) {
1138 if (zio->io_bp_orig.blk_birth != 0 &&
1139 spa_feature_is_active(spa, SPA_FEATURE_HOLE_BIRTH)) {
1140 BP_SET_LSIZE(bp, lsize);
1141 BP_SET_TYPE(bp, zp->zp_type);
1142 BP_SET_LEVEL(bp, zp->zp_level);
1143 BP_SET_BIRTH(bp, zio->io_txg, 0);
1144 }
1145 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1146 } else {
1147 ASSERT(zp->zp_checksum != ZIO_CHECKSUM_GANG_HEADER);
1148 BP_SET_LSIZE(bp, lsize);
1149 BP_SET_TYPE(bp, zp->zp_type);
1150 BP_SET_LEVEL(bp, zp->zp_level);
1151 BP_SET_PSIZE(bp, psize);
1152 BP_SET_COMPRESS(bp, compress);
1153 BP_SET_CHECKSUM(bp, zp->zp_checksum);
1154 BP_SET_DEDUP(bp, zp->zp_dedup);
1155 BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER);
1156 if (zp->zp_dedup) {
1157 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1158 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE));
1159 zio->io_pipeline = ZIO_DDT_WRITE_PIPELINE;
1160 }
1161 if (zp->zp_nopwrite) {
1162 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1163 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE));
1164 zio->io_pipeline |= ZIO_STAGE_NOP_WRITE;
1165 }
1166 }
1167
1168 return (ZIO_PIPELINE_CONTINUE);
1169 }
1170
1171 static int
1172 zio_free_bp_init(zio_t *zio)
1173 {
1174 blkptr_t *bp = zio->io_bp;
1175
1176 if (zio->io_child_type == ZIO_CHILD_LOGICAL) {
1177 if (BP_GET_DEDUP(bp))
1178 zio->io_pipeline = ZIO_DDT_FREE_PIPELINE;
1179 }
1180
1181 return (ZIO_PIPELINE_CONTINUE);
1182 }
1183
1184 /*
1185 * ==========================================================================
1186 * Execute the I/O pipeline
1187 * ==========================================================================
1188 */
1189
1190 static void
1191 zio_taskq_dispatch(zio_t *zio, zio_taskq_type_t q, boolean_t cutinline)
1192 {
1193 spa_t *spa = zio->io_spa;
1194 zio_type_t t = zio->io_type;
1195 int flags = (cutinline ? TQ_FRONT : 0);
1196
1197 /*
1198 * If we're a config writer or a probe, the normal issue and
1199 * interrupt threads may all be blocked waiting for the config lock.
1200 * In this case, select the otherwise-unused taskq for ZIO_TYPE_NULL.
1201 */
1202 if (zio->io_flags & (ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_PROBE))
1203 t = ZIO_TYPE_NULL;
1204
1205 /*
1206 * A similar issue exists for the L2ARC write thread until L2ARC 2.0.
1207 */
1208 if (t == ZIO_TYPE_WRITE && zio->io_vd && zio->io_vd->vdev_aux)
1209 t = ZIO_TYPE_NULL;
1210
1211 /*
1212 * If this is a high priority I/O, then use the high priority taskq if
1213 * available.
1214 */
1215 if (zio->io_priority == ZIO_PRIORITY_NOW &&
1216 spa->spa_zio_taskq[t][q + 1].stqs_count != 0)
1217 q++;
1218
1219 ASSERT3U(q, <, ZIO_TASKQ_TYPES);
1220
1221 /*
1222 * NB: We are assuming that the zio can only be dispatched
1223 * to a single taskq at a time. It would be a grievous error
1224 * to dispatch the zio to another taskq at the same time.
1225 */
1226 ASSERT(zio->io_tqent.tqent_next == NULL);
1227 spa_taskq_dispatch_ent(spa, t, q, (task_func_t *)zio_execute, zio,
1228 flags, &zio->io_tqent);
1229 }
1230
1231 static boolean_t
1232 zio_taskq_member(zio_t *zio, zio_taskq_type_t q)
1233 {
1234 kthread_t *executor = zio->io_executor;
1235 spa_t *spa = zio->io_spa;
1236
1237 for (zio_type_t t = 0; t < ZIO_TYPES; t++) {
1238 spa_taskqs_t *tqs = &spa->spa_zio_taskq[t][q];
1239 uint_t i;
1240 for (i = 0; i < tqs->stqs_count; i++) {
1241 if (taskq_member(tqs->stqs_taskq[i], executor))
1242 return (B_TRUE);
1243 }
1244 }
1245
1246 return (B_FALSE);
1247 }
1248
1249 static int
1250 zio_issue_async(zio_t *zio)
1251 {
1252 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE);
1253
1254 return (ZIO_PIPELINE_STOP);
1255 }
1256
1257 void
1258 zio_interrupt(zio_t *zio)
1259 {
1260 zio_taskq_dispatch(zio, ZIO_TASKQ_INTERRUPT, B_FALSE);
1261 }
1262
1263 /*
1264 * Execute the I/O pipeline until one of the following occurs:
1265 *
1266 * (1) the I/O completes
1267 * (2) the pipeline stalls waiting for dependent child I/Os
1268 * (3) the I/O issues, so we're waiting for an I/O completion interrupt
1269 * (4) the I/O is delegated by vdev-level caching or aggregation
1270 * (5) the I/O is deferred due to vdev-level queueing
1271 * (6) the I/O is handed off to another thread.
1272 *
1273 * In all cases, the pipeline stops whenever there's no CPU work; it never
1274 * burns a thread in cv_wait().
1275 *
1276 * There's no locking on io_stage because there's no legitimate way
1277 * for multiple threads to be attempting to process the same I/O.
1278 */
1279 static zio_pipe_stage_t *zio_pipeline[];
1280
1281 void
1282 zio_execute(zio_t *zio)
1283 {
1284 zio->io_executor = curthread;
1285
1286 while (zio->io_stage < ZIO_STAGE_DONE) {
1287 enum zio_stage pipeline = zio->io_pipeline;
1288 enum zio_stage stage = zio->io_stage;
1289 int rv;
1290
1291 ASSERT(!MUTEX_HELD(&zio->io_lock));
1292 ASSERT(ISP2(stage));
1293 ASSERT(zio->io_stall == NULL);
1294
1295 do {
1296 stage <<= 1;
1297 } while ((stage & pipeline) == 0);
1298
1299 ASSERT(stage <= ZIO_STAGE_DONE);
1300
1301 /*
1302 * If we are in interrupt context and this pipeline stage
1303 * will grab a config lock that is held across I/O,
1304 * or may wait for an I/O that needs an interrupt thread
1305 * to complete, issue async to avoid deadlock.
1306 *
1307 * For VDEV_IO_START, we cut in line so that the io will
1308 * be sent to disk promptly.
1309 */
1310 if ((stage & ZIO_BLOCKING_STAGES) && zio->io_vd == NULL &&
1311 zio_taskq_member(zio, ZIO_TASKQ_INTERRUPT)) {
1312 boolean_t cut = (stage == ZIO_STAGE_VDEV_IO_START) ?
1313 zio_requeue_io_start_cut_in_line : B_FALSE;
1314 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, cut);
1315 return;
1316 }
1317
1318 zio->io_stage = stage;
1319 rv = zio_pipeline[highbit64(stage) - 1](zio);
1320
1321 if (rv == ZIO_PIPELINE_STOP)
1322 return;
1323
1324 ASSERT(rv == ZIO_PIPELINE_CONTINUE);
1325 }
1326 }
1327
1328 /*
1329 * ==========================================================================
1330 * Initiate I/O, either sync or async
1331 * ==========================================================================
1332 */
1333 int
1334 zio_wait(zio_t *zio)
1335 {
1336 int error;
1337
1338 ASSERT(zio->io_stage == ZIO_STAGE_OPEN);
1339 ASSERT(zio->io_executor == NULL);
1340
1341 zio->io_waiter = curthread;
1342
1343 zio_execute(zio);
1344
1345 mutex_enter(&zio->io_lock);
1346 while (zio->io_executor != NULL)
1347 cv_wait(&zio->io_cv, &zio->io_lock);
1348 mutex_exit(&zio->io_lock);
1349
1350 error = zio->io_error;
1351 zio_destroy(zio);
1352
1353 return (error);
1354 }
1355
1356 void
1357 zio_nowait(zio_t *zio)
1358 {
1359 ASSERT(zio->io_executor == NULL);
1360
1361 if (zio->io_child_type == ZIO_CHILD_LOGICAL &&
1362 zio_unique_parent(zio) == NULL) {
1363 /*
1364 * This is a logical async I/O with no parent to wait for it.
1365 * We add it to the spa_async_root_zio "Godfather" I/O which
1366 * will ensure they complete prior to unloading the pool.
1367 */
1368 spa_t *spa = zio->io_spa;
1369
1370 zio_add_child(spa->spa_async_zio_root[CPU_SEQID], zio);
1371 }
1372
1373 zio_execute(zio);
1374 }
1375
1376 /*
1377 * ==========================================================================
1378 * Reexecute or suspend/resume failed I/O
1379 * ==========================================================================
1380 */
1381
1382 static void
1383 zio_reexecute(zio_t *pio)
1384 {
1385 zio_t *cio, *cio_next;
1386
1387 ASSERT(pio->io_child_type == ZIO_CHILD_LOGICAL);
1388 ASSERT(pio->io_orig_stage == ZIO_STAGE_OPEN);
1389 ASSERT(pio->io_gang_leader == NULL);
1390 ASSERT(pio->io_gang_tree == NULL);
1391
1392 pio->io_flags = pio->io_orig_flags;
1393 pio->io_stage = pio->io_orig_stage;
1394 pio->io_pipeline = pio->io_orig_pipeline;
1395 pio->io_reexecute = 0;
1396 pio->io_flags |= ZIO_FLAG_REEXECUTED;
1397 pio->io_error = 0;
1398 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
1399 pio->io_state[w] = 0;
1400 for (int c = 0; c < ZIO_CHILD_TYPES; c++)
1401 pio->io_child_error[c] = 0;
1402
1403 if (IO_IS_ALLOCATING(pio))
1404 BP_ZERO(pio->io_bp);
1405
1406 /*
1407 * As we reexecute pio's children, new children could be created.
1408 * New children go to the head of pio's io_child_list, however,
1409 * so we will (correctly) not reexecute them. The key is that
1410 * the remainder of pio's io_child_list, from 'cio_next' onward,
1411 * cannot be affected by any side effects of reexecuting 'cio'.
1412 */
1413 for (cio = zio_walk_children(pio); cio != NULL; cio = cio_next) {
1414 cio_next = zio_walk_children(pio);
1415 mutex_enter(&pio->io_lock);
1416 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
1417 pio->io_children[cio->io_child_type][w]++;
1418 mutex_exit(&pio->io_lock);
1419 zio_reexecute(cio);
1420 }
1421
1422 /*
1423 * Now that all children have been reexecuted, execute the parent.
1424 * We don't reexecute "The Godfather" I/O here as it's the
1425 * responsibility of the caller to wait on him.
1426 */
1427 if (!(pio->io_flags & ZIO_FLAG_GODFATHER))
1428 zio_execute(pio);
1429 }
1430
1431 void
1432 zio_suspend(spa_t *spa, zio_t *zio)
1433 {
1434 if (spa_get_failmode(spa) == ZIO_FAILURE_MODE_PANIC)
1435 fm_panic("Pool '%s' has encountered an uncorrectable I/O "
1436 "failure and the failure mode property for this pool "
1437 "is set to panic.", spa_name(spa));
1438
1439 zfs_ereport_post(FM_EREPORT_ZFS_IO_FAILURE, spa, NULL, NULL, 0, 0);
1440
1441 mutex_enter(&spa->spa_suspend_lock);
1442
1443 if (spa->spa_suspend_zio_root == NULL)
1444 spa->spa_suspend_zio_root = zio_root(spa, NULL, NULL,
1445 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE |
1446 ZIO_FLAG_GODFATHER);
1447
1448 spa->spa_suspended = B_TRUE;
1449
1450 if (zio != NULL) {
1451 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER));
1452 ASSERT(zio != spa->spa_suspend_zio_root);
1453 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1454 ASSERT(zio_unique_parent(zio) == NULL);
1455 ASSERT(zio->io_stage == ZIO_STAGE_DONE);
1456 zio_add_child(spa->spa_suspend_zio_root, zio);
1457 }
1458
1459 mutex_exit(&spa->spa_suspend_lock);
1460 }
1461
1462 int
1463 zio_resume(spa_t *spa)
1464 {
1465 zio_t *pio;
1466
1467 /*
1468 * Reexecute all previously suspended i/o.
1469 */
1470 mutex_enter(&spa->spa_suspend_lock);
1471 spa->spa_suspended = B_FALSE;
1472 cv_broadcast(&spa->spa_suspend_cv);
1473 pio = spa->spa_suspend_zio_root;
1474 spa->spa_suspend_zio_root = NULL;
1475 mutex_exit(&spa->spa_suspend_lock);
1476
1477 if (pio == NULL)
1478 return (0);
1479
1480 zio_reexecute(pio);
1481 return (zio_wait(pio));
1482 }
1483
1484 void
1485 zio_resume_wait(spa_t *spa)
1486 {
1487 mutex_enter(&spa->spa_suspend_lock);
1488 while (spa_suspended(spa))
1489 cv_wait(&spa->spa_suspend_cv, &spa->spa_suspend_lock);
1490 mutex_exit(&spa->spa_suspend_lock);
1491 }
1492
1493 /*
1494 * ==========================================================================
1495 * Gang blocks.
1496 *
1497 * A gang block is a collection of small blocks that looks to the DMU
1498 * like one large block. When zio_dva_allocate() cannot find a block
1499 * of the requested size, due to either severe fragmentation or the pool
1500 * being nearly full, it calls zio_write_gang_block() to construct the
1501 * block from smaller fragments.
1502 *
1503 * A gang block consists of a gang header (zio_gbh_phys_t) and up to
1504 * three (SPA_GBH_NBLKPTRS) gang members. The gang header is just like
1505 * an indirect block: it's an array of block pointers. It consumes
1506 * only one sector and hence is allocatable regardless of fragmentation.
1507 * The gang header's bps point to its gang members, which hold the data.
1508 *
1509 * Gang blocks are self-checksumming, using the bp's <vdev, offset, txg>
1510 * as the verifier to ensure uniqueness of the SHA256 checksum.
1511 * Critically, the gang block bp's blk_cksum is the checksum of the data,
1512 * not the gang header. This ensures that data block signatures (needed for
1513 * deduplication) are independent of how the block is physically stored.
1514 *
1515 * Gang blocks can be nested: a gang member may itself be a gang block.
1516 * Thus every gang block is a tree in which root and all interior nodes are
1517 * gang headers, and the leaves are normal blocks that contain user data.
1518 * The root of the gang tree is called the gang leader.
1519 *
1520 * To perform any operation (read, rewrite, free, claim) on a gang block,
1521 * zio_gang_assemble() first assembles the gang tree (minus data leaves)
1522 * in the io_gang_tree field of the original logical i/o by recursively
1523 * reading the gang leader and all gang headers below it. This yields
1524 * an in-core tree containing the contents of every gang header and the
1525 * bps for every constituent of the gang block.
1526 *
1527 * With the gang tree now assembled, zio_gang_issue() just walks the gang tree
1528 * and invokes a callback on each bp. To free a gang block, zio_gang_issue()
1529 * calls zio_free_gang() -- a trivial wrapper around zio_free() -- for each bp.
1530 * zio_claim_gang() provides a similarly trivial wrapper for zio_claim().
1531 * zio_read_gang() is a wrapper around zio_read() that omits reading gang
1532 * headers, since we already have those in io_gang_tree. zio_rewrite_gang()
1533 * performs a zio_rewrite() of the data or, for gang headers, a zio_rewrite()
1534 * of the gang header plus zio_checksum_compute() of the data to update the
1535 * gang header's blk_cksum as described above.
1536 *
1537 * The two-phase assemble/issue model solves the problem of partial failure --
1538 * what if you'd freed part of a gang block but then couldn't read the
1539 * gang header for another part? Assembling the entire gang tree first
1540 * ensures that all the necessary gang header I/O has succeeded before
1541 * starting the actual work of free, claim, or write. Once the gang tree
1542 * is assembled, free and claim are in-memory operations that cannot fail.
1543 *
1544 * In the event that a gang write fails, zio_dva_unallocate() walks the
1545 * gang tree to immediately free (i.e. insert back into the space map)
1546 * everything we've allocated. This ensures that we don't get ENOSPC
1547 * errors during repeated suspend/resume cycles due to a flaky device.
1548 *
1549 * Gang rewrites only happen during sync-to-convergence. If we can't assemble
1550 * the gang tree, we won't modify the block, so we can safely defer the free
1551 * (knowing that the block is still intact). If we *can* assemble the gang
1552 * tree, then even if some of the rewrites fail, zio_dva_unallocate() will free
1553 * each constituent bp and we can allocate a new block on the next sync pass.
1554 *
1555 * In all cases, the gang tree allows complete recovery from partial failure.
1556 * ==========================================================================
1557 */
1558
1559 static zio_t *
1560 zio_read_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1561 {
1562 if (gn != NULL)
1563 return (pio);
1564
1565 return (zio_read(pio, pio->io_spa, bp, data, BP_GET_PSIZE(bp),
1566 NULL, NULL, pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio),
1567 &pio->io_bookmark));
1568 }
1569
1570 zio_t *
1571 zio_rewrite_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1572 {
1573 zio_t *zio;
1574
1575 if (gn != NULL) {
1576 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp,
1577 gn->gn_gbh, SPA_GANGBLOCKSIZE, NULL, NULL, pio->io_priority,
1578 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
1579 /*
1580 * As we rewrite each gang header, the pipeline will compute
1581 * a new gang block header checksum for it; but no one will
1582 * compute a new data checksum, so we do that here. The one
1583 * exception is the gang leader: the pipeline already computed
1584 * its data checksum because that stage precedes gang assembly.
1585 * (Presently, nothing actually uses interior data checksums;
1586 * this is just good hygiene.)
1587 */
1588 if (gn != pio->io_gang_leader->io_gang_tree) {
1589 zio_checksum_compute(zio, BP_GET_CHECKSUM(bp),
1590 data, BP_GET_PSIZE(bp));
1591 }
1592 /*
1593 * If we are here to damage data for testing purposes,
1594 * leave the GBH alone so that we can detect the damage.
1595 */
1596 if (pio->io_gang_leader->io_flags & ZIO_FLAG_INDUCE_DAMAGE)
1597 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES;
1598 } else {
1599 zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp,
1600 data, BP_GET_PSIZE(bp), NULL, NULL, pio->io_priority,
1601 ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
1602 }
1603
1604 return (zio);
1605 }
1606
1607 /* ARGSUSED */
1608 zio_t *
1609 zio_free_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1610 {
1611 return (zio_free_sync(pio, pio->io_spa, pio->io_txg, bp,
1612 ZIO_GANG_CHILD_FLAGS(pio)));
1613 }
1614
1615 /* ARGSUSED */
1616 zio_t *
1617 zio_claim_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
1618 {
1619 return (zio_claim(pio, pio->io_spa, pio->io_txg, bp,
1620 NULL, NULL, ZIO_GANG_CHILD_FLAGS(pio)));
1621 }
1622
1623 static zio_gang_issue_func_t *zio_gang_issue_func[ZIO_TYPES] = {
1624 NULL,
1625 zio_read_gang,
1626 zio_rewrite_gang,
1627 zio_free_gang,
1628 zio_claim_gang,
1629 NULL
1630 };
1631
1632 static void zio_gang_tree_assemble_done(zio_t *zio);
1633
1634 static zio_gang_node_t *
1635 zio_gang_node_alloc(zio_gang_node_t **gnpp)
1636 {
1637 zio_gang_node_t *gn;
1638
1639 ASSERT(*gnpp == NULL);
1640
1641 gn = kmem_zalloc(sizeof (*gn), KM_SLEEP);
1642 gn->gn_gbh = zio_buf_alloc(SPA_GANGBLOCKSIZE);
1643 *gnpp = gn;
1644
1645 return (gn);
1646 }
1647
1648 static void
1649 zio_gang_node_free(zio_gang_node_t **gnpp)
1650 {
1651 zio_gang_node_t *gn = *gnpp;
1652
1653 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++)
1654 ASSERT(gn->gn_child[g] == NULL);
1655
1656 zio_buf_free(gn->gn_gbh, SPA_GANGBLOCKSIZE);
1657 kmem_free(gn, sizeof (*gn));
1658 *gnpp = NULL;
1659 }
1660
1661 static void
1662 zio_gang_tree_free(zio_gang_node_t **gnpp)
1663 {
1664 zio_gang_node_t *gn = *gnpp;
1665
1666 if (gn == NULL)
1667 return;
1668
1669 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++)
1670 zio_gang_tree_free(&gn->gn_child[g]);
1671
1672 zio_gang_node_free(gnpp);
1673 }
1674
1675 static void
1676 zio_gang_tree_assemble(zio_t *gio, blkptr_t *bp, zio_gang_node_t **gnpp)
1677 {
1678 zio_gang_node_t *gn = zio_gang_node_alloc(gnpp);
1679
1680 ASSERT(gio->io_gang_leader == gio);
1681 ASSERT(BP_IS_GANG(bp));
1682
1683 zio_nowait(zio_read(gio, gio->io_spa, bp, gn->gn_gbh,
1684 SPA_GANGBLOCKSIZE, zio_gang_tree_assemble_done, gn,
1685 gio->io_priority, ZIO_GANG_CHILD_FLAGS(gio), &gio->io_bookmark));
1686 }
1687
1688 static void
1689 zio_gang_tree_assemble_done(zio_t *zio)
1690 {
1691 zio_t *gio = zio->io_gang_leader;
1692 zio_gang_node_t *gn = zio->io_private;
1693 blkptr_t *bp = zio->io_bp;
1694
1695 ASSERT(gio == zio_unique_parent(zio));
1696 ASSERT(zio->io_child_count == 0);
1697
1698 if (zio->io_error)
1699 return;
1700
1701 if (BP_SHOULD_BYTESWAP(bp))
1702 byteswap_uint64_array(zio->io_data, zio->io_size);
1703
1704 ASSERT(zio->io_data == gn->gn_gbh);
1705 ASSERT(zio->io_size == SPA_GANGBLOCKSIZE);
1706 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC);
1707
1708 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
1709 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g];
1710 if (!BP_IS_GANG(gbp))
1711 continue;
1712 zio_gang_tree_assemble(gio, gbp, &gn->gn_child[g]);
1713 }
1714 }
1715
1716 static void
1717 zio_gang_tree_issue(zio_t *pio, zio_gang_node_t *gn, blkptr_t *bp, void *data)
1718 {
1719 zio_t *gio = pio->io_gang_leader;
1720 zio_t *zio;
1721
1722 ASSERT(BP_IS_GANG(bp) == !!gn);
1723 ASSERT(BP_GET_CHECKSUM(bp) == BP_GET_CHECKSUM(gio->io_bp));
1724 ASSERT(BP_GET_LSIZE(bp) == BP_GET_PSIZE(bp) || gn == gio->io_gang_tree);
1725
1726 /*
1727 * If you're a gang header, your data is in gn->gn_gbh.
1728 * If you're a gang member, your data is in 'data' and gn == NULL.
1729 */
1730 zio = zio_gang_issue_func[gio->io_type](pio, bp, gn, data);
1731
1732 if (gn != NULL) {
1733 ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_MAGIC);
1734
1735 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
1736 blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g];
1737 if (BP_IS_HOLE(gbp))
1738 continue;
1739 zio_gang_tree_issue(zio, gn->gn_child[g], gbp, data);
1740 data = (char *)data + BP_GET_PSIZE(gbp);
1741 }
1742 }
1743
1744 if (gn == gio->io_gang_tree)
1745 ASSERT3P((char *)gio->io_data + gio->io_size, ==, data);
1746
1747 if (zio != pio)
1748 zio_nowait(zio);
1749 }
1750
1751 static int
1752 zio_gang_assemble(zio_t *zio)
1753 {
1754 blkptr_t *bp = zio->io_bp;
1755
1756 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == NULL);
1757 ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
1758
1759 zio->io_gang_leader = zio;
1760
1761 zio_gang_tree_assemble(zio, bp, &zio->io_gang_tree);
1762
1763 return (ZIO_PIPELINE_CONTINUE);
1764 }
1765
1766 static int
1767 zio_gang_issue(zio_t *zio)
1768 {
1769 blkptr_t *bp = zio->io_bp;
1770
1771 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE))
1772 return (ZIO_PIPELINE_STOP);
1773
1774 ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == zio);
1775 ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
1776
1777 if (zio->io_child_error[ZIO_CHILD_GANG] == 0)
1778 zio_gang_tree_issue(zio, zio->io_gang_tree, bp, zio->io_data);
1779 else
1780 zio_gang_tree_free(&zio->io_gang_tree);
1781
1782 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1783
1784 return (ZIO_PIPELINE_CONTINUE);
1785 }
1786
1787 static void
1788 zio_write_gang_member_ready(zio_t *zio)
1789 {
1790 zio_t *pio = zio_unique_parent(zio);
1791 zio_t *gio = zio->io_gang_leader;
1792 dva_t *cdva = zio->io_bp->blk_dva;
1793 dva_t *pdva = pio->io_bp->blk_dva;
1794 uint64_t asize;
1795
1796 if (BP_IS_HOLE(zio->io_bp))
1797 return;
1798
1799 ASSERT(BP_IS_HOLE(&zio->io_bp_orig));
1800
1801 ASSERT(zio->io_child_type == ZIO_CHILD_GANG);
1802 ASSERT3U(zio->io_prop.zp_copies, ==, gio->io_prop.zp_copies);
1803 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(zio->io_bp));
1804 ASSERT3U(pio->io_prop.zp_copies, <=, BP_GET_NDVAS(pio->io_bp));
1805 ASSERT3U(BP_GET_NDVAS(zio->io_bp), <=, BP_GET_NDVAS(pio->io_bp));
1806
1807 mutex_enter(&pio->io_lock);
1808 for (int d = 0; d < BP_GET_NDVAS(zio->io_bp); d++) {
1809 ASSERT(DVA_GET_GANG(&pdva[d]));
1810 asize = DVA_GET_ASIZE(&pdva[d]);
1811 asize += DVA_GET_ASIZE(&cdva[d]);
1812 DVA_SET_ASIZE(&pdva[d], asize);
1813 }
1814 mutex_exit(&pio->io_lock);
1815 }
1816
1817 static int
1818 zio_write_gang_block(zio_t *pio)
1819 {
1820 spa_t *spa = pio->io_spa;
1821 blkptr_t *bp = pio->io_bp;
1822 zio_t *gio = pio->io_gang_leader;
1823 zio_t *zio;
1824 zio_gang_node_t *gn, **gnpp;
1825 zio_gbh_phys_t *gbh;
1826 uint64_t txg = pio->io_txg;
1827 uint64_t resid = pio->io_size;
1828 uint64_t lsize;
1829 int copies = gio->io_prop.zp_copies;
1830 int gbh_copies = MIN(copies + 1, spa_max_replication(spa));
1831 zio_prop_t zp;
1832 int error;
1833
1834 error = metaslab_alloc(spa, spa_normal_class(spa), SPA_GANGBLOCKSIZE,
1835 bp, gbh_copies, txg, pio == gio ? NULL : gio->io_bp,
1836 METASLAB_HINTBP_FAVOR | METASLAB_GANG_HEADER);
1837 if (error) {
1838 pio->io_error = error;
1839 return (ZIO_PIPELINE_CONTINUE);
1840 }
1841
1842 if (pio == gio) {
1843 gnpp = &gio->io_gang_tree;
1844 } else {
1845 gnpp = pio->io_private;
1846 ASSERT(pio->io_ready == zio_write_gang_member_ready);
1847 }
1848
1849 gn = zio_gang_node_alloc(gnpp);
1850 gbh = gn->gn_gbh;
1851 bzero(gbh, SPA_GANGBLOCKSIZE);
1852
1853 /*
1854 * Create the gang header.
1855 */
1856 zio = zio_rewrite(pio, spa, txg, bp, gbh, SPA_GANGBLOCKSIZE, NULL, NULL,
1857 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
1858
1859 /*
1860 * Create and nowait the gang children.
1861 */
1862 for (int g = 0; resid != 0; resid -= lsize, g++) {
1863 lsize = P2ROUNDUP(resid / (SPA_GBH_NBLKPTRS - g),
1864 SPA_MINBLOCKSIZE);
1865 ASSERT(lsize >= SPA_MINBLOCKSIZE && lsize <= resid);
1866
1867 zp.zp_checksum = gio->io_prop.zp_checksum;
1868 zp.zp_compress = ZIO_COMPRESS_OFF;
1869 zp.zp_type = DMU_OT_NONE;
1870 zp.zp_level = 0;
1871 zp.zp_copies = gio->io_prop.zp_copies;
1872 zp.zp_dedup = B_FALSE;
1873 zp.zp_dedup_verify = B_FALSE;
1874 zp.zp_nopwrite = B_FALSE;
1875
1876 zio_nowait(zio_write(zio, spa, txg, &gbh->zg_blkptr[g],
1877 (char *)pio->io_data + (pio->io_size - resid), lsize, &zp,
1878 zio_write_gang_member_ready, NULL, NULL, &gn->gn_child[g],
1879 pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio),
1880 &pio->io_bookmark));
1881 }
1882
1883 /*
1884 * Set pio's pipeline to just wait for zio to finish.
1885 */
1886 pio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1887
1888 zio_nowait(zio);
1889
1890 return (ZIO_PIPELINE_CONTINUE);
1891 }
1892
1893 /*
1894 * The zio_nop_write stage in the pipeline determines if allocating
1895 * a new bp is necessary. By leveraging a cryptographically secure checksum,
1896 * such as SHA256, we can compare the checksums of the new data and the old
1897 * to determine if allocating a new block is required. The nopwrite
1898 * feature can handle writes in either syncing or open context (i.e. zil
1899 * writes) and as a result is mutually exclusive with dedup.
1900 */
1901 static int
1902 zio_nop_write(zio_t *zio)
1903 {
1904 blkptr_t *bp = zio->io_bp;
1905 blkptr_t *bp_orig = &zio->io_bp_orig;
1906 zio_prop_t *zp = &zio->io_prop;
1907
1908 ASSERT(BP_GET_LEVEL(bp) == 0);
1909 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE));
1910 ASSERT(zp->zp_nopwrite);
1911 ASSERT(!zp->zp_dedup);
1912 ASSERT(zio->io_bp_override == NULL);
1913 ASSERT(IO_IS_ALLOCATING(zio));
1914
1915 /*
1916 * Check to see if the original bp and the new bp have matching
1917 * characteristics (i.e. same checksum, compression algorithms, etc).
1918 * If they don't then just continue with the pipeline which will
1919 * allocate a new bp.
1920 */
1921 if (BP_IS_HOLE(bp_orig) ||
1922 !zio_checksum_table[BP_GET_CHECKSUM(bp)].ci_dedup ||
1923 BP_GET_CHECKSUM(bp) != BP_GET_CHECKSUM(bp_orig) ||
1924 BP_GET_COMPRESS(bp) != BP_GET_COMPRESS(bp_orig) ||
1925 BP_GET_DEDUP(bp) != BP_GET_DEDUP(bp_orig) ||
1926 zp->zp_copies != BP_GET_NDVAS(bp_orig))
1927 return (ZIO_PIPELINE_CONTINUE);
1928
1929 /*
1930 * If the checksums match then reset the pipeline so that we
1931 * avoid allocating a new bp and issuing any I/O.
1932 */
1933 if (ZIO_CHECKSUM_EQUAL(bp->blk_cksum, bp_orig->blk_cksum)) {
1934 ASSERT(zio_checksum_table[zp->zp_checksum].ci_dedup);
1935 ASSERT3U(BP_GET_PSIZE(bp), ==, BP_GET_PSIZE(bp_orig));
1936 ASSERT3U(BP_GET_LSIZE(bp), ==, BP_GET_LSIZE(bp_orig));
1937 ASSERT(zp->zp_compress != ZIO_COMPRESS_OFF);
1938 ASSERT(bcmp(&bp->blk_prop, &bp_orig->blk_prop,
1939 sizeof (uint64_t)) == 0);
1940
1941 *bp = *bp_orig;
1942 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
1943 zio->io_flags |= ZIO_FLAG_NOPWRITE;
1944 }
1945
1946 return (ZIO_PIPELINE_CONTINUE);
1947 }
1948
1949 /*
1950 * ==========================================================================
1951 * Dedup
1952 * ==========================================================================
1953 */
1954 static void
1955 zio_ddt_child_read_done(zio_t *zio)
1956 {
1957 blkptr_t *bp = zio->io_bp;
1958 ddt_entry_t *dde = zio->io_private;
1959 ddt_phys_t *ddp;
1960 zio_t *pio = zio_unique_parent(zio);
1961
1962 mutex_enter(&pio->io_lock);
1963 ddp = ddt_phys_select(dde, bp);
1964 if (zio->io_error == 0)
1965 ddt_phys_clear(ddp); /* this ddp doesn't need repair */
1966 if (zio->io_error == 0 && dde->dde_repair_data == NULL)
1967 dde->dde_repair_data = zio->io_data;
1968 else
1969 zio_buf_free(zio->io_data, zio->io_size);
1970 mutex_exit(&pio->io_lock);
1971 }
1972
1973 static int
1974 zio_ddt_read_start(zio_t *zio)
1975 {
1976 blkptr_t *bp = zio->io_bp;
1977
1978 ASSERT(BP_GET_DEDUP(bp));
1979 ASSERT(BP_GET_PSIZE(bp) == zio->io_size);
1980 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
1981
1982 if (zio->io_child_error[ZIO_CHILD_DDT]) {
1983 ddt_t *ddt = ddt_select(zio->io_spa, bp);
1984 ddt_entry_t *dde = ddt_repair_start(ddt, bp);
1985 ddt_phys_t *ddp = dde->dde_phys;
1986 ddt_phys_t *ddp_self = ddt_phys_select(dde, bp);
1987 blkptr_t blk;
1988
1989 ASSERT(zio->io_vsd == NULL);
1990 zio->io_vsd = dde;
1991
1992 if (ddp_self == NULL)
1993 return (ZIO_PIPELINE_CONTINUE);
1994
1995 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
1996 if (ddp->ddp_phys_birth == 0 || ddp == ddp_self)
1997 continue;
1998 ddt_bp_create(ddt->ddt_checksum, &dde->dde_key, ddp,
1999 &blk);
2000 zio_nowait(zio_read(zio, zio->io_spa, &blk,
2001 zio_buf_alloc(zio->io_size), zio->io_size,
2002 zio_ddt_child_read_done, dde, zio->io_priority,
2003 ZIO_DDT_CHILD_FLAGS(zio) | ZIO_FLAG_DONT_PROPAGATE,
2004 &zio->io_bookmark));
2005 }
2006 return (ZIO_PIPELINE_CONTINUE);
2007 }
2008
2009 zio_nowait(zio_read(zio, zio->io_spa, bp,
2010 zio->io_data, zio->io_size, NULL, NULL, zio->io_priority,
2011 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark));
2012
2013 return (ZIO_PIPELINE_CONTINUE);
2014 }
2015
2016 static int
2017 zio_ddt_read_done(zio_t *zio)
2018 {
2019 blkptr_t *bp = zio->io_bp;
2020
2021 if (zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE))
2022 return (ZIO_PIPELINE_STOP);
2023
2024 ASSERT(BP_GET_DEDUP(bp));
2025 ASSERT(BP_GET_PSIZE(bp) == zio->io_size);
2026 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
2027
2028 if (zio->io_child_error[ZIO_CHILD_DDT]) {
2029 ddt_t *ddt = ddt_select(zio->io_spa, bp);
2030 ddt_entry_t *dde = zio->io_vsd;
2031 if (ddt == NULL) {
2032 ASSERT(spa_load_state(zio->io_spa) != SPA_LOAD_NONE);
2033 return (ZIO_PIPELINE_CONTINUE);
2034 }
2035 if (dde == NULL) {
2036 zio->io_stage = ZIO_STAGE_DDT_READ_START >> 1;
2037 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE);
2038 return (ZIO_PIPELINE_STOP);
2039 }
2040 if (dde->dde_repair_data != NULL) {
2041 bcopy(dde->dde_repair_data, zio->io_data, zio->io_size);
2042 zio->io_child_error[ZIO_CHILD_DDT] = 0;
2043 }
2044 ddt_repair_done(ddt, dde);
2045 zio->io_vsd = NULL;
2046 }
2047
2048 ASSERT(zio->io_vsd == NULL);
2049
2050 return (ZIO_PIPELINE_CONTINUE);
2051 }
2052
2053 static boolean_t
2054 zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde)
2055 {
2056 spa_t *spa = zio->io_spa;
2057
2058 /*
2059 * Note: we compare the original data, not the transformed data,
2060 * because when zio->io_bp is an override bp, we will not have
2061 * pushed the I/O transforms. That's an important optimization
2062 * because otherwise we'd compress/encrypt all dmu_sync() data twice.
2063 */
2064 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
2065 zio_t *lio = dde->dde_lead_zio[p];
2066
2067 if (lio != NULL) {
2068 return (lio->io_orig_size != zio->io_orig_size ||
2069 bcmp(zio->io_orig_data, lio->io_orig_data,
2070 zio->io_orig_size) != 0);
2071 }
2072 }
2073
2074 for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
2075 ddt_phys_t *ddp = &dde->dde_phys[p];
2076
2077 if (ddp->ddp_phys_birth != 0) {
2078 arc_buf_t *abuf = NULL;
2079 uint32_t aflags = ARC_WAIT;
2080 blkptr_t blk = *zio->io_bp;
2081 int error;
2082
2083 ddt_bp_fill(ddp, &blk, ddp->ddp_phys_birth);
2084
2085 ddt_exit(ddt);
2086
2087 error = arc_read(NULL, spa, &blk,
2088 arc_getbuf_func, &abuf, ZIO_PRIORITY_SYNC_READ,
2089 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
2090 &aflags, &zio->io_bookmark);
2091
2092 if (error == 0) {
2093 if (arc_buf_size(abuf) != zio->io_orig_size ||
2094 bcmp(abuf->b_data, zio->io_orig_data,
2095 zio->io_orig_size) != 0)
2096 error = SET_ERROR(EEXIST);
2097 VERIFY(arc_buf_remove_ref(abuf, &abuf));
2098 }
2099
2100 ddt_enter(ddt);
2101 return (error != 0);
2102 }
2103 }
2104
2105 return (B_FALSE);
2106 }
2107
2108 static void
2109 zio_ddt_child_write_ready(zio_t *zio)
2110 {
2111 int p = zio->io_prop.zp_copies;
2112 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp);
2113 ddt_entry_t *dde = zio->io_private;
2114 ddt_phys_t *ddp = &dde->dde_phys[p];
2115 zio_t *pio;
2116
2117 if (zio->io_error)
2118 return;
2119
2120 ddt_enter(ddt);
2121
2122 ASSERT(dde->dde_lead_zio[p] == zio);
2123
2124 ddt_phys_fill(ddp, zio->io_bp);
2125
2126 while ((pio = zio_walk_parents(zio)) != NULL)
2127 ddt_bp_fill(ddp, pio->io_bp, zio->io_txg);
2128
2129 ddt_exit(ddt);
2130 }
2131
2132 static void
2133 zio_ddt_child_write_done(zio_t *zio)
2134 {
2135 int p = zio->io_prop.zp_copies;
2136 ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp);
2137 ddt_entry_t *dde = zio->io_private;
2138 ddt_phys_t *ddp = &dde->dde_phys[p];
2139
2140 ddt_enter(ddt);
2141
2142 ASSERT(ddp->ddp_refcnt == 0);
2143 ASSERT(dde->dde_lead_zio[p] == zio);
2144 dde->dde_lead_zio[p] = NULL;
2145
2146 if (zio->io_error == 0) {
2147 while (zio_walk_parents(zio) != NULL)
2148 ddt_phys_addref(ddp);
2149 } else {
2150 ddt_phys_clear(ddp);
2151 }
2152
2153 ddt_exit(ddt);
2154 }
2155
2156 static void
2157 zio_ddt_ditto_write_done(zio_t *zio)
2158 {
2159 int p = DDT_PHYS_DITTO;
2160 zio_prop_t *zp = &zio->io_prop;
2161 blkptr_t *bp = zio->io_bp;
2162 ddt_t *ddt = ddt_select(zio->io_spa, bp);
2163 ddt_entry_t *dde = zio->io_private;
2164 ddt_phys_t *ddp = &dde->dde_phys[p];
2165 ddt_key_t *ddk = &dde->dde_key;
2166
2167 ddt_enter(ddt);
2168
2169 ASSERT(ddp->ddp_refcnt == 0);
2170 ASSERT(dde->dde_lead_zio[p] == zio);
2171 dde->dde_lead_zio[p] = NULL;
2172
2173 if (zio->io_error == 0) {
2174 ASSERT(ZIO_CHECKSUM_EQUAL(bp->blk_cksum, ddk->ddk_cksum));
2175 ASSERT(zp->zp_copies < SPA_DVAS_PER_BP);
2176 ASSERT(zp->zp_copies == BP_GET_NDVAS(bp) - BP_IS_GANG(bp));
2177 if (ddp->ddp_phys_birth != 0)
2178 ddt_phys_free(ddt, ddk, ddp, zio->io_txg);
2179 ddt_phys_fill(ddp, bp);
2180 }
2181
2182 ddt_exit(ddt);
2183 }
2184
2185 static int
2186 zio_ddt_write(zio_t *zio)
2187 {
2188 spa_t *spa = zio->io_spa;
2189 blkptr_t *bp = zio->io_bp;
2190 uint64_t txg = zio->io_txg;
2191 zio_prop_t *zp = &zio->io_prop;
2192 int p = zp->zp_copies;
2193 int ditto_copies;
2194 zio_t *cio = NULL;
2195 zio_t *dio = NULL;
2196 ddt_t *ddt = ddt_select(spa, bp);
2197 ddt_entry_t *dde;
2198 ddt_phys_t *ddp;
2199
2200 ASSERT(BP_GET_DEDUP(bp));
2201 ASSERT(BP_GET_CHECKSUM(bp) == zp->zp_checksum);
2202 ASSERT(BP_IS_HOLE(bp) || zio->io_bp_override);
2203
2204 ddt_enter(ddt);
2205 dde = ddt_lookup(ddt, bp, B_TRUE);
2206 ddp = &dde->dde_phys[p];
2207
2208 if (zp->zp_dedup_verify && zio_ddt_collision(zio, ddt, dde)) {
2209 /*
2210 * If we're using a weak checksum, upgrade to a strong checksum
2211 * and try again. If we're already using a strong checksum,
2212 * we can't resolve it, so just convert to an ordinary write.
2213 * (And automatically e-mail a paper to Nature?)
2214 */
2215 if (!zio_checksum_table[zp->zp_checksum].ci_dedup) {
2216 zp->zp_checksum = spa_dedup_checksum(spa);
2217 zio_pop_transforms(zio);
2218 zio->io_stage = ZIO_STAGE_OPEN;
2219 BP_ZERO(bp);
2220 } else {
2221 zp->zp_dedup = B_FALSE;
2222 }
2223 zio->io_pipeline = ZIO_WRITE_PIPELINE;
2224 ddt_exit(ddt);
2225 return (ZIO_PIPELINE_CONTINUE);
2226 }
2227
2228 ditto_copies = ddt_ditto_copies_needed(ddt, dde, ddp);
2229 ASSERT(ditto_copies < SPA_DVAS_PER_BP);
2230
2231 if (ditto_copies > ddt_ditto_copies_present(dde) &&
2232 dde->dde_lead_zio[DDT_PHYS_DITTO] == NULL) {
2233 zio_prop_t czp = *zp;
2234
2235 czp.zp_copies = ditto_copies;
2236
2237 /*
2238 * If we arrived here with an override bp, we won't have run
2239 * the transform stack, so we won't have the data we need to
2240 * generate a child i/o. So, toss the override bp and restart.
2241 * This is safe, because using the override bp is just an
2242 * optimization; and it's rare, so the cost doesn't matter.
2243 */
2244 if (zio->io_bp_override) {
2245 zio_pop_transforms(zio);
2246 zio->io_stage = ZIO_STAGE_OPEN;
2247 zio->io_pipeline = ZIO_WRITE_PIPELINE;
2248 zio->io_bp_override = NULL;
2249 BP_ZERO(bp);
2250 ddt_exit(ddt);
2251 return (ZIO_PIPELINE_CONTINUE);
2252 }
2253
2254 dio = zio_write(zio, spa, txg, bp, zio->io_orig_data,
2255 zio->io_orig_size, &czp, NULL, NULL,
2256 zio_ddt_ditto_write_done, dde, zio->io_priority,
2257 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark);
2258
2259 zio_push_transform(dio, zio->io_data, zio->io_size, 0, NULL);
2260 dde->dde_lead_zio[DDT_PHYS_DITTO] = dio;
2261 }
2262
2263 if (ddp->ddp_phys_birth != 0 || dde->dde_lead_zio[p] != NULL) {
2264 if (ddp->ddp_phys_birth != 0)
2265 ddt_bp_fill(ddp, bp, txg);
2266 if (dde->dde_lead_zio[p] != NULL)
2267 zio_add_child(zio, dde->dde_lead_zio[p]);
2268 else
2269 ddt_phys_addref(ddp);
2270 } else if (zio->io_bp_override) {
2271 ASSERT(bp->blk_birth == txg);
2272 ASSERT(BP_EQUAL(bp, zio->io_bp_override));
2273 ddt_phys_fill(ddp, bp);
2274 ddt_phys_addref(ddp);
2275 } else {
2276 cio = zio_write(zio, spa, txg, bp, zio->io_orig_data,
2277 zio->io_orig_size, zp, zio_ddt_child_write_ready, NULL,
2278 zio_ddt_child_write_done, dde, zio->io_priority,
2279 ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark);
2280
2281 zio_push_transform(cio, zio->io_data, zio->io_size, 0, NULL);
2282 dde->dde_lead_zio[p] = cio;
2283 }
2284
2285 ddt_exit(ddt);
2286
2287 if (cio)
2288 zio_nowait(cio);
2289 if (dio)
2290 zio_nowait(dio);
2291
2292 return (ZIO_PIPELINE_CONTINUE);
2293 }
2294
2295 ddt_entry_t *freedde; /* for debugging */
2296
2297 static int
2298 zio_ddt_free(zio_t *zio)
2299 {
2300 spa_t *spa = zio->io_spa;
2301 blkptr_t *bp = zio->io_bp;
2302 ddt_t *ddt = ddt_select(spa, bp);
2303 ddt_entry_t *dde;
2304 ddt_phys_t *ddp;
2305
2306 ASSERT(BP_GET_DEDUP(bp));
2307 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
2308
2309 ddt_enter(ddt);
2310 freedde = dde = ddt_lookup(ddt, bp, B_TRUE);
2311 ddp = ddt_phys_select(dde, bp);
2312 ddt_phys_decref(ddp);
2313 ddt_exit(ddt);
2314
2315 return (ZIO_PIPELINE_CONTINUE);
2316 }
2317
2318 /*
2319 * ==========================================================================
2320 * Allocate and free blocks
2321 * ==========================================================================
2322 */
2323 static int
2324 zio_dva_allocate(zio_t *zio)
2325 {
2326 spa_t *spa = zio->io_spa;
2327 metaslab_class_t *mc = spa_normal_class(spa);
2328 blkptr_t *bp = zio->io_bp;
2329 int error;
2330 int flags = 0;
2331
2332 if (zio->io_gang_leader == NULL) {
2333 ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
2334 zio->io_gang_leader = zio;
2335 }
2336
2337 ASSERT(BP_IS_HOLE(bp));
2338 ASSERT0(BP_GET_NDVAS(bp));
2339 ASSERT3U(zio->io_prop.zp_copies, >, 0);
2340 ASSERT3U(zio->io_prop.zp_copies, <=, spa_max_replication(spa));
2341 ASSERT3U(zio->io_size, ==, BP_GET_PSIZE(bp));
2342
2343 /*
2344 * The dump device does not support gang blocks so allocation on
2345 * behalf of the dump device (i.e. ZIO_FLAG_NODATA) must avoid
2346 * the "fast" gang feature.
2347 */
2348 flags |= (zio->io_flags & ZIO_FLAG_NODATA) ? METASLAB_GANG_AVOID : 0;
2349 flags |= (zio->io_flags & ZIO_FLAG_GANG_CHILD) ?
2350 METASLAB_GANG_CHILD : 0;
2351 error = metaslab_alloc(spa, mc, zio->io_size, bp,
2352 zio->io_prop.zp_copies, zio->io_txg, NULL, flags);
2353
2354 if (error) {
2355 spa_dbgmsg(spa, "%s: metaslab allocation failure: zio %p, "
2356 "size %llu, error %d", spa_name(spa), zio, zio->io_size,
2357 error);
2358 if (error == ENOSPC && zio->io_size > SPA_MINBLOCKSIZE)
2359 return (zio_write_gang_block(zio));
2360 zio->io_error = error;
2361 }
2362
2363 return (ZIO_PIPELINE_CONTINUE);
2364 }
2365
2366 static int
2367 zio_dva_free(zio_t *zio)
2368 {
2369 metaslab_free(zio->io_spa, zio->io_bp, zio->io_txg, B_FALSE);
2370
2371 return (ZIO_PIPELINE_CONTINUE);
2372 }
2373
2374 static int
2375 zio_dva_claim(zio_t *zio)
2376 {
2377 int error;
2378
2379 error = metaslab_claim(zio->io_spa, zio->io_bp, zio->io_txg);
2380 if (error)
2381 zio->io_error = error;
2382
2383 return (ZIO_PIPELINE_CONTINUE);
2384 }
2385
2386 /*
2387 * Undo an allocation. This is used by zio_done() when an I/O fails
2388 * and we want to give back the block we just allocated.
2389 * This handles both normal blocks and gang blocks.
2390 */
2391 static void
2392 zio_dva_unallocate(zio_t *zio, zio_gang_node_t *gn, blkptr_t *bp)
2393 {
2394 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp));
2395 ASSERT(zio->io_bp_override == NULL);
2396
2397 if (!BP_IS_HOLE(bp))
2398 metaslab_free(zio->io_spa, bp, bp->blk_birth, B_TRUE);
2399
2400 if (gn != NULL) {
2401 for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
2402 zio_dva_unallocate(zio, gn->gn_child[g],
2403 &gn->gn_gbh->zg_blkptr[g]);
2404 }
2405 }
2406 }
2407
2408 /*
2409 * Try to allocate an intent log block. Return 0 on success, errno on failure.
2410 */
2411 int
2412 zio_alloc_zil(spa_t *spa, uint64_t txg, blkptr_t *new_bp, blkptr_t *old_bp,
2413 uint64_t size, boolean_t use_slog)
2414 {
2415 int error = 1;
2416
2417 ASSERT(txg > spa_syncing_txg(spa));
2418
2419 /*
2420 * ZIL blocks are always contiguous (i.e. not gang blocks) so we
2421 * set the METASLAB_GANG_AVOID flag so that they don't "fast gang"
2422 * when allocating them.
2423 */
2424 if (use_slog) {
2425 error = metaslab_alloc(spa, spa_log_class(spa), size,
2426 new_bp, 1, txg, old_bp,
2427 METASLAB_HINTBP_AVOID | METASLAB_GANG_AVOID);
2428 }
2429
2430 if (error) {
2431 error = metaslab_alloc(spa, spa_normal_class(spa), size,
2432 new_bp, 1, txg, old_bp,
2433 METASLAB_HINTBP_AVOID);
2434 }
2435
2436 if (error == 0) {
2437 BP_SET_LSIZE(new_bp, size);
2438 BP_SET_PSIZE(new_bp, size);
2439 BP_SET_COMPRESS(new_bp, ZIO_COMPRESS_OFF);
2440 BP_SET_CHECKSUM(new_bp,
2441 spa_version(spa) >= SPA_VERSION_SLIM_ZIL
2442 ? ZIO_CHECKSUM_ZILOG2 : ZIO_CHECKSUM_ZILOG);
2443 BP_SET_TYPE(new_bp, DMU_OT_INTENT_LOG);
2444 BP_SET_LEVEL(new_bp, 0);
2445 BP_SET_DEDUP(new_bp, 0);
2446 BP_SET_BYTEORDER(new_bp, ZFS_HOST_BYTEORDER);
2447 }
2448
2449 return (error);
2450 }
2451
2452 /*
2453 * Free an intent log block.
2454 */
2455 void
2456 zio_free_zil(spa_t *spa, uint64_t txg, blkptr_t *bp)
2457 {
2458 ASSERT(BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG);
2459 ASSERT(!BP_IS_GANG(bp));
2460
2461 zio_free(spa, txg, bp);
2462 }
2463
2464 /*
2465 * ==========================================================================
2466 * Read and write to physical devices
2467 * ==========================================================================
2468 */
2469
2470
2471 /*
2472 * Issue an I/O to the underlying vdev. Typically the issue pipeline
2473 * stops after this stage and will resume upon I/O completion.
2474 * However, there are instances where the vdev layer may need to
2475 * continue the pipeline when an I/O was not issued. Since the I/O
2476 * that was sent to the vdev layer might be different than the one
2477 * currently active in the pipeline (see vdev_queue_io()), we explicitly
2478 * force the underlying vdev layers to call either zio_execute() or
2479 * zio_interrupt() to ensure that the pipeline continues with the correct I/O.
2480 */
2481 static int
2482 zio_vdev_io_start(zio_t *zio)
2483 {
2484 vdev_t *vd = zio->io_vd;
2485 uint64_t align;
2486 spa_t *spa = zio->io_spa;
2487
2488 ASSERT(zio->io_error == 0);
2489 ASSERT(zio->io_child_error[ZIO_CHILD_VDEV] == 0);
2490
2491 if (vd == NULL) {
2492 if (!(zio->io_flags & ZIO_FLAG_CONFIG_WRITER))
2493 spa_config_enter(spa, SCL_ZIO, zio, RW_READER);
2494
2495 /*
2496 * The mirror_ops handle multiple DVAs in a single BP.
2497 */
2498 vdev_mirror_ops.vdev_op_io_start(zio);
2499 return (ZIO_PIPELINE_STOP);
2500 }
2501
2502 /*
2503 * We keep track of time-sensitive I/Os so that the scan thread
2504 * can quickly react to certain workloads. In particular, we care
2505 * about non-scrubbing, top-level reads and writes with the following
2506 * characteristics:
2507 * - synchronous writes of user data to non-slog devices
2508 * - any reads of user data
2509 * When these conditions are met, adjust the timestamp of spa_last_io
2510 * which allows the scan thread to adjust its workload accordingly.
2511 */
2512 if (!(zio->io_flags & ZIO_FLAG_SCAN_THREAD) && zio->io_bp != NULL &&
2513 vd == vd->vdev_top && !vd->vdev_islog &&
2514 zio->io_bookmark.zb_objset != DMU_META_OBJSET &&
2515 zio->io_txg != spa_syncing_txg(spa)) {
2516 uint64_t old = spa->spa_last_io;
2517 uint64_t new = ddi_get_lbolt64();
2518 if (old != new)
2519 (void) atomic_cas_64(&spa->spa_last_io, old, new);
2520 }
2521
2522 align = 1ULL << vd->vdev_top->vdev_ashift;
2523
2524 if (!(zio->io_flags & ZIO_FLAG_PHYSICAL) &&
2525 P2PHASE(zio->io_size, align) != 0) {
2526 /* Transform logical writes to be a full physical block size. */
2527 uint64_t asize = P2ROUNDUP(zio->io_size, align);
2528 char *abuf = zio_buf_alloc(asize);
2529 ASSERT(vd == vd->vdev_top);
2530 if (zio->io_type == ZIO_TYPE_WRITE) {
2531 bcopy(zio->io_data, abuf, zio->io_size);
2532 bzero(abuf + zio->io_size, asize - zio->io_size);
2533 }
2534 zio_push_transform(zio, abuf, asize, asize, zio_subblock);
2535 }
2536
2537 /*
2538 * If this is not a physical io, make sure that it is properly aligned
2539 * before proceeding.
2540 */
2541 if (!(zio->io_flags & ZIO_FLAG_PHYSICAL)) {
2542 ASSERT0(P2PHASE(zio->io_offset, align));
2543 ASSERT0(P2PHASE(zio->io_size, align));
2544 } else {
2545 /*
2546 * For physical writes, we allow 512b aligned writes and assume
2547 * the device will perform a read-modify-write as necessary.
2548 */
2549 ASSERT0(P2PHASE(zio->io_offset, SPA_MINBLOCKSIZE));
2550 ASSERT0(P2PHASE(zio->io_size, SPA_MINBLOCKSIZE));
2551 }
2552
2553 VERIFY(zio->io_type != ZIO_TYPE_WRITE || spa_writeable(spa));
2554
2555 /*
2556 * If this is a repair I/O, and there's no self-healing involved --
2557 * that is, we're just resilvering what we expect to resilver --
2558 * then don't do the I/O unless zio's txg is actually in vd's DTL.
2559 * This prevents spurious resilvering with nested replication.
2560 * For example, given a mirror of mirrors, (A+B)+(C+D), if only
2561 * A is out of date, we'll read from C+D, then use the data to
2562 * resilver A+B -- but we don't actually want to resilver B, just A.
2563 * The top-level mirror has no way to know this, so instead we just
2564 * discard unnecessary repairs as we work our way down the vdev tree.
2565 * The same logic applies to any form of nested replication:
2566 * ditto + mirror, RAID-Z + replacing, etc. This covers them all.
2567 */
2568 if ((zio->io_flags & ZIO_FLAG_IO_REPAIR) &&
2569 !(zio->io_flags & ZIO_FLAG_SELF_HEAL) &&
2570 zio->io_txg != 0 && /* not a delegated i/o */
2571 !vdev_dtl_contains(vd, DTL_PARTIAL, zio->io_txg, 1)) {
2572 ASSERT(zio->io_type == ZIO_TYPE_WRITE);
2573 zio_vdev_io_bypass(zio);
2574 return (ZIO_PIPELINE_CONTINUE);
2575 }
2576
2577 if (vd->vdev_ops->vdev_op_leaf &&
2578 (zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE)) {
2579
2580 if (zio->io_type == ZIO_TYPE_READ && vdev_cache_read(zio))
2581 return (ZIO_PIPELINE_CONTINUE);
2582
2583 if ((zio = vdev_queue_io(zio)) == NULL)
2584 return (ZIO_PIPELINE_STOP);
2585
2586 if (!vdev_accessible(vd, zio)) {
2587 zio->io_error = SET_ERROR(ENXIO);
2588 zio_interrupt(zio);
2589 return (ZIO_PIPELINE_STOP);
2590 }
2591 }
2592
2593 vd->vdev_ops->vdev_op_io_start(zio);
2594 return (ZIO_PIPELINE_STOP);
2595 }
2596
2597 static int
2598 zio_vdev_io_done(zio_t *zio)
2599 {
2600 vdev_t *vd = zio->io_vd;
2601 vdev_ops_t *ops = vd ? vd->vdev_ops : &vdev_mirror_ops;
2602 boolean_t unexpected_error = B_FALSE;
2603
2604 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE))
2605 return (ZIO_PIPELINE_STOP);
2606
2607 ASSERT(zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE);
2608
2609 if (vd != NULL && vd->vdev_ops->vdev_op_leaf) {
2610
2611 vdev_queue_io_done(zio);
2612
2613 if (zio->io_type == ZIO_TYPE_WRITE)
2614 vdev_cache_write(zio);
2615
2616 if (zio_injection_enabled && zio->io_error == 0)
2617 zio->io_error = zio_handle_device_injection(vd,
2618 zio, EIO);
2619
2620 if (zio_injection_enabled && zio->io_error == 0)
2621 zio->io_error = zio_handle_label_injection(zio, EIO);
2622
2623 if (zio->io_error) {
2624 if (!vdev_accessible(vd, zio)) {
2625 zio->io_error = SET_ERROR(ENXIO);
2626 } else {
2627 unexpected_error = B_TRUE;
2628 }
2629 }
2630 }
2631
2632 ops->vdev_op_io_done(zio);
2633
2634 if (unexpected_error)
2635 VERIFY(vdev_probe(vd, zio) == NULL);
2636
2637 return (ZIO_PIPELINE_CONTINUE);
2638 }
2639
2640 /*
2641 * For non-raidz ZIOs, we can just copy aside the bad data read from the
2642 * disk, and use that to finish the checksum ereport later.
2643 */
2644 static void
2645 zio_vsd_default_cksum_finish(zio_cksum_report_t *zcr,
2646 const void *good_buf)
2647 {
2648 /* no processing needed */
2649 zfs_ereport_finish_checksum(zcr, good_buf, zcr->zcr_cbdata, B_FALSE);
2650 }
2651
2652 /*ARGSUSED*/
2653 void
2654 zio_vsd_default_cksum_report(zio_t *zio, zio_cksum_report_t *zcr, void *ignored)
2655 {
2656 void *buf = zio_buf_alloc(zio->io_size);
2657
2658 bcopy(zio->io_data, buf, zio->io_size);
2659
2660 zcr->zcr_cbinfo = zio->io_size;
2661 zcr->zcr_cbdata = buf;
2662 zcr->zcr_finish = zio_vsd_default_cksum_finish;
2663 zcr->zcr_free = zio_buf_free;
2664 }
2665
2666 static int
2667 zio_vdev_io_assess(zio_t *zio)
2668 {
2669 vdev_t *vd = zio->io_vd;
2670
2671 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE))
2672 return (ZIO_PIPELINE_STOP);
2673
2674 if (vd == NULL && !(zio->io_flags & ZIO_FLAG_CONFIG_WRITER))
2675 spa_config_exit(zio->io_spa, SCL_ZIO, zio);
2676
2677 if (zio->io_vsd != NULL) {
2678 zio->io_vsd_ops->vsd_free(zio);
2679 zio->io_vsd = NULL;
2680 }
2681
2682 if (zio_injection_enabled && zio->io_error == 0)
2683 zio->io_error = zio_handle_fault_injection(zio, EIO);
2684
2685 /*
2686 * If the I/O failed, determine whether we should attempt to retry it.
2687 *
2688 * On retry, we cut in line in the issue queue, since we don't want
2689 * compression/checksumming/etc. work to prevent our (cheap) IO reissue.
2690 */
2691 if (zio->io_error && vd == NULL &&
2692 !(zio->io_flags & (ZIO_FLAG_DONT_RETRY | ZIO_FLAG_IO_RETRY))) {
2693 ASSERT(!(zio->io_flags & ZIO_FLAG_DONT_QUEUE)); /* not a leaf */
2694 ASSERT(!(zio->io_flags & ZIO_FLAG_IO_BYPASS)); /* not a leaf */
2695 zio->io_error = 0;
2696 zio->io_flags |= ZIO_FLAG_IO_RETRY |
2697 ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE;
2698 zio->io_stage = ZIO_STAGE_VDEV_IO_START >> 1;
2699 zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE,
2700 zio_requeue_io_start_cut_in_line);
2701 return (ZIO_PIPELINE_STOP);
2702 }
2703
2704 /*
2705 * If we got an error on a leaf device, convert it to ENXIO
2706 * if the device is not accessible at all.
2707 */
2708 if (zio->io_error && vd != NULL && vd->vdev_ops->vdev_op_leaf &&
2709 !vdev_accessible(vd, zio))
2710 zio->io_error = SET_ERROR(ENXIO);
2711
2712 /*
2713 * If we can't write to an interior vdev (mirror or RAID-Z),
2714 * set vdev_cant_write so that we stop trying to allocate from it.
2715 */
2716 if (zio->io_error == ENXIO && zio->io_type == ZIO_TYPE_WRITE &&
2717 vd != NULL && !vd->vdev_ops->vdev_op_leaf) {
2718 vd->vdev_cant_write = B_TRUE;
2719 }
2720
2721 if (zio->io_error)
2722 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
2723
2724 if (vd != NULL && vd->vdev_ops->vdev_op_leaf &&
2725 zio->io_physdone != NULL) {
2726 ASSERT(!(zio->io_flags & ZIO_FLAG_DELEGATED));
2727 ASSERT(zio->io_child_type == ZIO_CHILD_VDEV);
2728 zio->io_physdone(zio->io_logical);
2729 }
2730
2731 return (ZIO_PIPELINE_CONTINUE);
2732 }
2733
2734 void
2735 zio_vdev_io_reissue(zio_t *zio)
2736 {
2737 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START);
2738 ASSERT(zio->io_error == 0);
2739
2740 zio->io_stage >>= 1;
2741 }
2742
2743 void
2744 zio_vdev_io_redone(zio_t *zio)
2745 {
2746 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_DONE);
2747
2748 zio->io_stage >>= 1;
2749 }
2750
2751 void
2752 zio_vdev_io_bypass(zio_t *zio)
2753 {
2754 ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START);
2755 ASSERT(zio->io_error == 0);
2756
2757 zio->io_flags |= ZIO_FLAG_IO_BYPASS;
2758 zio->io_stage = ZIO_STAGE_VDEV_IO_ASSESS >> 1;
2759 }
2760
2761 /*
2762 * ==========================================================================
2763 * Generate and verify checksums
2764 * ==========================================================================
2765 */
2766 static int
2767 zio_checksum_generate(zio_t *zio)
2768 {
2769 blkptr_t *bp = zio->io_bp;
2770 enum zio_checksum checksum;
2771
2772 if (bp == NULL) {
2773 /*
2774 * This is zio_write_phys().
2775 * We're either generating a label checksum, or none at all.
2776 */
2777 checksum = zio->io_prop.zp_checksum;
2778
2779 if (checksum == ZIO_CHECKSUM_OFF)
2780 return (ZIO_PIPELINE_CONTINUE);
2781
2782 ASSERT(checksum == ZIO_CHECKSUM_LABEL);
2783 } else {
2784 if (BP_IS_GANG(bp) && zio->io_child_type == ZIO_CHILD_GANG) {
2785 ASSERT(!IO_IS_ALLOCATING(zio));
2786 checksum = ZIO_CHECKSUM_GANG_HEADER;
2787 } else {
2788 checksum = BP_GET_CHECKSUM(bp);
2789 }
2790 }
2791
2792 zio_checksum_compute(zio, checksum, zio->io_data, zio->io_size);
2793
2794 return (ZIO_PIPELINE_CONTINUE);
2795 }
2796
2797 static int
2798 zio_checksum_verify(zio_t *zio)
2799 {
2800 zio_bad_cksum_t info;
2801 blkptr_t *bp = zio->io_bp;
2802 int error;
2803
2804 ASSERT(zio->io_vd != NULL);
2805
2806 if (bp == NULL) {
2807 /*
2808 * This is zio_read_phys().
2809 * We're either verifying a label checksum, or nothing at all.
2810 */
2811 if (zio->io_prop.zp_checksum == ZIO_CHECKSUM_OFF)
2812 return (ZIO_PIPELINE_CONTINUE);
2813
2814 ASSERT(zio->io_prop.zp_checksum == ZIO_CHECKSUM_LABEL);
2815 }
2816
2817 if ((error = zio_checksum_error(zio, &info)) != 0) {
2818 zio->io_error = error;
2819 if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) {
2820 zfs_ereport_start_checksum(zio->io_spa,
2821 zio->io_vd, zio, zio->io_offset,
2822 zio->io_size, NULL, &info);
2823 }
2824 }
2825
2826 return (ZIO_PIPELINE_CONTINUE);
2827 }
2828
2829 /*
2830 * Called by RAID-Z to ensure we don't compute the checksum twice.
2831 */
2832 void
2833 zio_checksum_verified(zio_t *zio)
2834 {
2835 zio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY;
2836 }
2837
2838 /*
2839 * ==========================================================================
2840 * Error rank. Error are ranked in the order 0, ENXIO, ECKSUM, EIO, other.
2841 * An error of 0 indicates success. ENXIO indicates whole-device failure,
2842 * which may be transient (e.g. unplugged) or permament. ECKSUM and EIO
2843 * indicate errors that are specific to one I/O, and most likely permanent.
2844 * Any other error is presumed to be worse because we weren't expecting it.
2845 * ==========================================================================
2846 */
2847 int
2848 zio_worst_error(int e1, int e2)
2849 {
2850 static int zio_error_rank[] = { 0, ENXIO, ECKSUM, EIO };
2851 int r1, r2;
2852
2853 for (r1 = 0; r1 < sizeof (zio_error_rank) / sizeof (int); r1++)
2854 if (e1 == zio_error_rank[r1])
2855 break;
2856
2857 for (r2 = 0; r2 < sizeof (zio_error_rank) / sizeof (int); r2++)
2858 if (e2 == zio_error_rank[r2])
2859 break;
2860
2861 return (r1 > r2 ? e1 : e2);
2862 }
2863
2864 /*
2865 * ==========================================================================
2866 * I/O completion
2867 * ==========================================================================
2868 */
2869 static int
2870 zio_ready(zio_t *zio)
2871 {
2872 blkptr_t *bp = zio->io_bp;
2873 zio_t *pio, *pio_next;
2874
2875 if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) ||
2876 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_READY))
2877 return (ZIO_PIPELINE_STOP);
2878
2879 if (zio->io_ready) {
2880 ASSERT(IO_IS_ALLOCATING(zio));
2881 ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp) ||
2882 (zio->io_flags & ZIO_FLAG_NOPWRITE));
2883 ASSERT(zio->io_children[ZIO_CHILD_GANG][ZIO_WAIT_READY] == 0);
2884
2885 zio->io_ready(zio);
2886 }
2887
2888 if (bp != NULL && bp != &zio->io_bp_copy)
2889 zio->io_bp_copy = *bp;
2890
2891 if (zio->io_error)
2892 zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
2893
2894 mutex_enter(&zio->io_lock);
2895 zio->io_state[ZIO_WAIT_READY] = 1;
2896 pio = zio_walk_parents(zio);
2897 mutex_exit(&zio->io_lock);
2898
2899 /*
2900 * As we notify zio's parents, new parents could be added.
2901 * New parents go to the head of zio's io_parent_list, however,
2902 * so we will (correctly) not notify them. The remainder of zio's
2903 * io_parent_list, from 'pio_next' onward, cannot change because
2904 * all parents must wait for us to be done before they can be done.
2905 */
2906 for (; pio != NULL; pio = pio_next) {
2907 pio_next = zio_walk_parents(zio);
2908 zio_notify_parent(pio, zio, ZIO_WAIT_READY);
2909 }
2910
2911 if (zio->io_flags & ZIO_FLAG_NODATA) {
2912 if (BP_IS_GANG(bp)) {
2913 zio->io_flags &= ~ZIO_FLAG_NODATA;
2914 } else {
2915 ASSERT((uintptr_t)zio->io_data < SPA_MAXBLOCKSIZE);
2916 zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES;
2917 }
2918 }
2919
2920 if (zio_injection_enabled &&
2921 zio->io_spa->spa_syncing_txg == zio->io_txg)
2922 zio_handle_ignored_writes(zio);
2923
2924 return (ZIO_PIPELINE_CONTINUE);
2925 }
2926
2927 static int
2928 zio_done(zio_t *zio)
2929 {
2930 spa_t *spa = zio->io_spa;
2931 zio_t *lio = zio->io_logical;
2932 blkptr_t *bp = zio->io_bp;
2933 vdev_t *vd = zio->io_vd;
2934 uint64_t psize = zio->io_size;
2935 zio_t *pio, *pio_next;
2936
2937 /*
2938 * If our children haven't all completed,
2939 * wait for them and then repeat this pipeline stage.
2940 */
2941 if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE) ||
2942 zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE) ||
2943 zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE) ||
2944 zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_DONE))
2945 return (ZIO_PIPELINE_STOP);
2946
2947 for (int c = 0; c < ZIO_CHILD_TYPES; c++)
2948 for (int w = 0; w < ZIO_WAIT_TYPES; w++)
2949 ASSERT(zio->io_children[c][w] == 0);
2950
2951 if (bp != NULL && !BP_IS_EMBEDDED(bp)) {
2952 ASSERT(bp->blk_pad[0] == 0);
2953 ASSERT(bp->blk_pad[1] == 0);
2954 ASSERT(bcmp(bp, &zio->io_bp_copy, sizeof (blkptr_t)) == 0 ||
2955 (bp == zio_unique_parent(zio)->io_bp));
2956 if (zio->io_type == ZIO_TYPE_WRITE && !BP_IS_HOLE(bp) &&
2957 zio->io_bp_override == NULL &&
2958 !(zio->io_flags & ZIO_FLAG_IO_REPAIR)) {
2959 ASSERT(!BP_SHOULD_BYTESWAP(bp));
2960 ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(bp));
2961 ASSERT(BP_COUNT_GANG(bp) == 0 ||
2962 (BP_COUNT_GANG(bp) == BP_GET_NDVAS(bp)));
2963 }
2964 if (zio->io_flags & ZIO_FLAG_NOPWRITE)
2965 VERIFY(BP_EQUAL(bp, &zio->io_bp_orig));
2966 }
2967
2968 /*
2969 * If there were child vdev/gang/ddt errors, they apply to us now.
2970 */
2971 zio_inherit_child_errors(zio, ZIO_CHILD_VDEV);
2972 zio_inherit_child_errors(zio, ZIO_CHILD_GANG);
2973 zio_inherit_child_errors(zio, ZIO_CHILD_DDT);
2974
2975 /*
2976 * If the I/O on the transformed data was successful, generate any
2977 * checksum reports now while we still have the transformed data.
2978 */
2979 if (zio->io_error == 0) {
2980 while (zio->io_cksum_report != NULL) {
2981 zio_cksum_report_t *zcr = zio->io_cksum_report;
2982 uint64_t align = zcr->zcr_align;
2983 uint64_t asize = P2ROUNDUP(psize, align);
2984 char *abuf = zio->io_data;
2985
2986 if (asize != psize) {
2987 abuf = zio_buf_alloc(asize);
2988 bcopy(zio->io_data, abuf, psize);
2989 bzero(abuf + psize, asize - psize);
2990 }
2991
2992 zio->io_cksum_report = zcr->zcr_next;
2993 zcr->zcr_next = NULL;
2994 zcr->zcr_finish(zcr, abuf);
2995 zfs_ereport_free_checksum(zcr);
2996
2997 if (asize != psize)
2998 zio_buf_free(abuf, asize);
2999 }
3000 }
3001
3002 zio_pop_transforms(zio); /* note: may set zio->io_error */
3003
3004 vdev_stat_update(zio, psize);
3005
3006 if (zio->io_error) {
3007 /*
3008 * If this I/O is attached to a particular vdev,
3009 * generate an error message describing the I/O failure
3010 * at the block level. We ignore these errors if the
3011 * device is currently unavailable.
3012 */
3013 if (zio->io_error != ECKSUM && vd != NULL && !vdev_is_dead(vd))
3014 zfs_ereport_post(FM_EREPORT_ZFS_IO, spa, vd, zio, 0, 0);
3015
3016 if ((zio->io_error == EIO || !(zio->io_flags &
3017 (ZIO_FLAG_SPECULATIVE | ZIO_FLAG_DONT_PROPAGATE))) &&
3018 zio == lio) {
3019 /*
3020 * For logical I/O requests, tell the SPA to log the
3021 * error and generate a logical data ereport.
3022 */
3023 spa_log_error(spa, zio);
3024 zfs_ereport_post(FM_EREPORT_ZFS_DATA, spa, NULL, zio,
3025 0, 0);
3026 }
3027 }
3028
3029 if (zio->io_error && zio == lio) {
3030 /*
3031 * Determine whether zio should be reexecuted. This will
3032 * propagate all the way to the root via zio_notify_parent().
3033 */
3034 ASSERT(vd == NULL && bp != NULL);
3035 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
3036
3037 if (IO_IS_ALLOCATING(zio) &&
3038 !(zio->io_flags & ZIO_FLAG_CANFAIL)) {
3039 if (zio->io_error != ENOSPC)
3040 zio->io_reexecute |= ZIO_REEXECUTE_NOW;
3041 else
3042 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
3043 }
3044
3045 if ((zio->io_type == ZIO_TYPE_READ ||
3046 zio->io_type == ZIO_TYPE_FREE) &&
3047 !(zio->io_flags & ZIO_FLAG_SCAN_THREAD) &&
3048 zio->io_error == ENXIO &&
3049 spa_load_state(spa) == SPA_LOAD_NONE &&
3050 spa_get_failmode(spa) != ZIO_FAILURE_MODE_CONTINUE)
3051 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
3052
3053 if (!(zio->io_flags & ZIO_FLAG_CANFAIL) && !zio->io_reexecute)
3054 zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
3055
3056 /*
3057 * Here is a possibly good place to attempt to do
3058 * either combinatorial reconstruction or error correction
3059 * based on checksums. It also might be a good place
3060 * to send out preliminary ereports before we suspend
3061 * processing.
3062 */
3063 }
3064
3065 /*
3066 * If there were logical child errors, they apply to us now.
3067 * We defer this until now to avoid conflating logical child
3068 * errors with errors that happened to the zio itself when
3069 * updating vdev stats and reporting FMA events above.
3070 */
3071 zio_inherit_child_errors(zio, ZIO_CHILD_LOGICAL);
3072
3073 if ((zio->io_error || zio->io_reexecute) &&
3074 IO_IS_ALLOCATING(zio) && zio->io_gang_leader == zio &&
3075 !(zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)))
3076 zio_dva_unallocate(zio, zio->io_gang_tree, bp);
3077
3078 zio_gang_tree_free(&zio->io_gang_tree);
3079
3080 /*
3081 * Godfather I/Os should never suspend.
3082 */
3083 if ((zio->io_flags & ZIO_FLAG_GODFATHER) &&
3084 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND))
3085 zio->io_reexecute = 0;
3086
3087 if (zio->io_reexecute) {
3088 /*
3089 * This is a logical I/O that wants to reexecute.
3090 *
3091 * Reexecute is top-down. When an i/o fails, if it's not
3092 * the root, it simply notifies its parent and sticks around.
3093 * The parent, seeing that it still has children in zio_done(),
3094 * does the same. This percolates all the way up to the root.
3095 * The root i/o will reexecute or suspend the entire tree.
3096 *
3097 * This approach ensures that zio_reexecute() honors
3098 * all the original i/o dependency relationships, e.g.
3099 * parents not executing until children are ready.
3100 */
3101 ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
3102
3103 zio->io_gang_leader = NULL;
3104
3105 mutex_enter(&zio->io_lock);
3106 zio->io_state[ZIO_WAIT_DONE] = 1;
3107 mutex_exit(&zio->io_lock);
3108
3109 /*
3110 * "The Godfather" I/O monitors its children but is
3111 * not a true parent to them. It will track them through
3112 * the pipeline but severs its ties whenever they get into
3113 * trouble (e.g. suspended). This allows "The Godfather"
3114 * I/O to return status without blocking.
3115 */
3116 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) {
3117 zio_link_t *zl = zio->io_walk_link;
3118 pio_next = zio_walk_parents(zio);
3119
3120 if ((pio->io_flags & ZIO_FLAG_GODFATHER) &&
3121 (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND)) {
3122 zio_remove_child(pio, zio, zl);
3123 zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
3124 }
3125 }
3126
3127 if ((pio = zio_unique_parent(zio)) != NULL) {
3128 /*
3129 * We're not a root i/o, so there's nothing to do
3130 * but notify our parent. Don't propagate errors
3131 * upward since we haven't permanently failed yet.
3132 */
3133 ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER));
3134 zio->io_flags |= ZIO_FLAG_DONT_PROPAGATE;
3135 zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
3136 } else if (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND) {
3137 /*
3138 * We'd fail again if we reexecuted now, so suspend
3139 * until conditions improve (e.g. device comes online).
3140 */
3141 zio_suspend(spa, zio);
3142 } else {
3143 /*
3144 * Reexecution is potentially a huge amount of work.
3145 * Hand it off to the otherwise-unused claim taskq.
3146 */
3147 ASSERT(zio->io_tqent.tqent_next == NULL);
3148 spa_taskq_dispatch_ent(spa, ZIO_TYPE_CLAIM,
3149 ZIO_TASKQ_ISSUE, (task_func_t *)zio_reexecute, zio,
3150 0, &zio->io_tqent);
3151 }
3152 return (ZIO_PIPELINE_STOP);
3153 }
3154
3155 ASSERT(zio->io_child_count == 0);
3156 ASSERT(zio->io_reexecute == 0);
3157 ASSERT(zio->io_error == 0 || (zio->io_flags & ZIO_FLAG_CANFAIL));
3158
3159 /*
3160 * Report any checksum errors, since the I/O is complete.
3161 */
3162 while (zio->io_cksum_report != NULL) {
3163 zio_cksum_report_t *zcr = zio->io_cksum_report;
3164 zio->io_cksum_report = zcr->zcr_next;
3165 zcr->zcr_next = NULL;
3166 zcr->zcr_finish(zcr, NULL);
3167 zfs_ereport_free_checksum(zcr);
3168 }
3169
3170 /*
3171 * It is the responsibility of the done callback to ensure that this
3172 * particular zio is no longer discoverable for adoption, and as
3173 * such, cannot acquire any new parents.
3174 */
3175 if (zio->io_done)
3176 zio->io_done(zio);
3177
3178 mutex_enter(&zio->io_lock);
3179 zio->io_state[ZIO_WAIT_DONE] = 1;
3180 mutex_exit(&zio->io_lock);
3181
3182 for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) {
3183 zio_link_t *zl = zio->io_walk_link;
3184 pio_next = zio_walk_parents(zio);
3185 zio_remove_child(pio, zio, zl);
3186 zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
3187 }
3188
3189 if (zio->io_waiter != NULL) {
3190 mutex_enter(&zio->io_lock);
3191 zio->io_executor = NULL;
3192 cv_broadcast(&zio->io_cv);
3193 mutex_exit(&zio->io_lock);
3194 } else {
3195 zio_destroy(zio);
3196 }
3197
3198 return (ZIO_PIPELINE_STOP);
3199 }
3200
3201 /*
3202 * ==========================================================================
3203 * I/O pipeline definition
3204 * ==========================================================================
3205 */
3206 static zio_pipe_stage_t *zio_pipeline[] = {
3207 NULL,
3208 zio_read_bp_init,
3209 zio_free_bp_init,
3210 zio_issue_async,
3211 zio_write_bp_init,
3212 zio_checksum_generate,
3213 zio_nop_write,
3214 zio_ddt_read_start,
3215 zio_ddt_read_done,
3216 zio_ddt_write,
3217 zio_ddt_free,
3218 zio_gang_assemble,
3219 zio_gang_issue,
3220 zio_dva_allocate,
3221 zio_dva_free,
3222 zio_dva_claim,
3223 zio_ready,
3224 zio_vdev_io_start,
3225 zio_vdev_io_done,
3226 zio_vdev_io_assess,
3227 zio_checksum_verify,
3228 zio_done
3229 };
3230
3231 /* dnp is the dnode for zb1->zb_object */
3232 boolean_t
3233 zbookmark_is_before(const dnode_phys_t *dnp, const zbookmark_phys_t *zb1,
3234 const zbookmark_phys_t *zb2)
3235 {
3236 uint64_t zb1nextL0, zb2thisobj;
3237
3238 ASSERT(zb1->zb_objset == zb2->zb_objset);
3239 ASSERT(zb2->zb_level == 0);
3240
3241 /* The objset_phys_t isn't before anything. */
3242 if (dnp == NULL)
3243 return (B_FALSE);
3244
3245 zb1nextL0 = (zb1->zb_blkid + 1) <<
3246 ((zb1->zb_level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT));
3247
3248 zb2thisobj = zb2->zb_object ? zb2->zb_object :
3249 zb2->zb_blkid << (DNODE_BLOCK_SHIFT - DNODE_SHIFT);
3250
3251 if (zb1->zb_object == DMU_META_DNODE_OBJECT) {
3252 uint64_t nextobj = zb1nextL0 *
3253 (dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT) >> DNODE_SHIFT;
3254 return (nextobj <= zb2thisobj);
3255 }
3256
3257 if (zb1->zb_object < zb2thisobj)
3258 return (B_TRUE);
3259 if (zb1->zb_object > zb2thisobj)
3260 return (B_FALSE);
3261 if (zb2->zb_object == DMU_META_DNODE_OBJECT)
3262 return (B_FALSE);
3263 return (zb1nextL0 <= zb2->zb_blkid);
3264 }