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