xref: /illumos-gate/usr/src/uts/common/fs/zfs/sys/zio.h (revision 7ab4e62e3b5c454f248a38bec0d489e8f5543324)
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 /*
23  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
25  * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
26  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
27  * Copyright (c) 2013, Joyent, Inc. All rights reserved.
28  */
29 
30 #ifndef _ZIO_H
31 #define	_ZIO_H
32 
33 #include <sys/zfs_context.h>
34 #include <sys/spa.h>
35 #include <sys/txg.h>
36 #include <sys/avl.h>
37 #include <sys/fs/zfs.h>
38 #include <sys/zio_impl.h>
39 
40 #ifdef	__cplusplus
41 extern "C" {
42 #endif
43 
44 /*
45  * Embedded checksum
46  */
47 #define	ZEC_MAGIC	0x210da7ab10c7a11ULL
48 
49 typedef struct zio_eck {
50 	uint64_t	zec_magic;	/* for validation, endianness	*/
51 	zio_cksum_t	zec_cksum;	/* 256-bit checksum		*/
52 } zio_eck_t;
53 
54 /*
55  * Gang block headers are self-checksumming and contain an array
56  * of block pointers.
57  */
58 #define	SPA_GANGBLOCKSIZE	SPA_MINBLOCKSIZE
59 #define	SPA_GBH_NBLKPTRS	((SPA_GANGBLOCKSIZE - \
60 	sizeof (zio_eck_t)) / sizeof (blkptr_t))
61 #define	SPA_GBH_FILLER		((SPA_GANGBLOCKSIZE - \
62 	sizeof (zio_eck_t) - \
63 	(SPA_GBH_NBLKPTRS * sizeof (blkptr_t))) /\
64 	sizeof (uint64_t))
65 
66 typedef struct zio_gbh {
67 	blkptr_t		zg_blkptr[SPA_GBH_NBLKPTRS];
68 	uint64_t		zg_filler[SPA_GBH_FILLER];
69 	zio_eck_t		zg_tail;
70 } zio_gbh_phys_t;
71 
72 enum zio_checksum {
73 	ZIO_CHECKSUM_INHERIT = 0,
74 	ZIO_CHECKSUM_ON,
75 	ZIO_CHECKSUM_OFF,
76 	ZIO_CHECKSUM_LABEL,
77 	ZIO_CHECKSUM_GANG_HEADER,
78 	ZIO_CHECKSUM_ZILOG,
79 	ZIO_CHECKSUM_FLETCHER_2,
80 	ZIO_CHECKSUM_FLETCHER_4,
81 	ZIO_CHECKSUM_SHA256,
82 	ZIO_CHECKSUM_ZILOG2,
83 	ZIO_CHECKSUM_NOPARITY,
84 	ZIO_CHECKSUM_FUNCTIONS
85 };
86 
87 /*
88  * The number of "legacy" compression functions which can be set on individual
89  * objects.
90  */
91 #define	ZIO_CHECKSUM_LEGACY_FUNCTIONS ZIO_CHECKSUM_ZILOG2
92 
93 #define	ZIO_CHECKSUM_ON_VALUE	ZIO_CHECKSUM_FLETCHER_4
94 #define	ZIO_CHECKSUM_DEFAULT	ZIO_CHECKSUM_ON
95 
96 #define	ZIO_CHECKSUM_MASK	0xffULL
97 #define	ZIO_CHECKSUM_VERIFY	(1 << 8)
98 
99 #define	ZIO_DEDUPCHECKSUM	ZIO_CHECKSUM_SHA256
100 #define	ZIO_DEDUPDITTO_MIN	100
101 
102 enum zio_compress {
103 	ZIO_COMPRESS_INHERIT = 0,
104 	ZIO_COMPRESS_ON,
105 	ZIO_COMPRESS_OFF,
106 	ZIO_COMPRESS_LZJB,
107 	ZIO_COMPRESS_EMPTY,
108 	ZIO_COMPRESS_GZIP_1,
109 	ZIO_COMPRESS_GZIP_2,
110 	ZIO_COMPRESS_GZIP_3,
111 	ZIO_COMPRESS_GZIP_4,
112 	ZIO_COMPRESS_GZIP_5,
113 	ZIO_COMPRESS_GZIP_6,
114 	ZIO_COMPRESS_GZIP_7,
115 	ZIO_COMPRESS_GZIP_8,
116 	ZIO_COMPRESS_GZIP_9,
117 	ZIO_COMPRESS_ZLE,
118 	ZIO_COMPRESS_LZ4,
119 	ZIO_COMPRESS_FUNCTIONS
120 };
121 
122 /*
123  * The number of "legacy" compression functions which can be set on individual
124  * objects.
125  */
126 #define	ZIO_COMPRESS_LEGACY_FUNCTIONS ZIO_COMPRESS_LZ4
127 
128 /* N.B. when altering this value, also change BOOTFS_COMPRESS_VALID below */
129 #define	ZIO_COMPRESS_ON_VALUE	ZIO_COMPRESS_LZJB
130 #define	ZIO_COMPRESS_DEFAULT	ZIO_COMPRESS_OFF
131 
132 #define	BOOTFS_COMPRESS_VALID(compress)			\
133 	((compress) == ZIO_COMPRESS_LZJB ||		\
134 	(compress) == ZIO_COMPRESS_LZ4 ||		\
135 	((compress) == ZIO_COMPRESS_ON &&		\
136 	ZIO_COMPRESS_ON_VALUE == ZIO_COMPRESS_LZJB) ||	\
137 	(compress) == ZIO_COMPRESS_OFF)
138 
139 #define	ZIO_FAILURE_MODE_WAIT		0
140 #define	ZIO_FAILURE_MODE_CONTINUE	1
141 #define	ZIO_FAILURE_MODE_PANIC		2
142 
143 typedef enum zio_priority {
144 	ZIO_PRIORITY_SYNC_READ,
145 	ZIO_PRIORITY_SYNC_WRITE,	/* ZIL */
146 	ZIO_PRIORITY_ASYNC_READ,	/* prefetch */
147 	ZIO_PRIORITY_ASYNC_WRITE,	/* spa_sync() */
148 	ZIO_PRIORITY_SCRUB,		/* asynchronous scrub/resilver reads */
149 	ZIO_PRIORITY_NUM_QUEUEABLE,
150 
151 	ZIO_PRIORITY_NOW		/* non-queued i/os (e.g. free) */
152 } zio_priority_t;
153 
154 #define	ZIO_PIPELINE_CONTINUE		0x100
155 #define	ZIO_PIPELINE_STOP		0x101
156 
157 enum zio_flag {
158 	/*
159 	 * Flags inherited by gang, ddt, and vdev children,
160 	 * and that must be equal for two zios to aggregate
161 	 */
162 	ZIO_FLAG_DONT_AGGREGATE	= 1 << 0,
163 	ZIO_FLAG_IO_REPAIR	= 1 << 1,
164 	ZIO_FLAG_SELF_HEAL	= 1 << 2,
165 	ZIO_FLAG_RESILVER	= 1 << 3,
166 	ZIO_FLAG_SCRUB		= 1 << 4,
167 	ZIO_FLAG_SCAN_THREAD	= 1 << 5,
168 	ZIO_FLAG_PHYSICAL	= 1 << 6,
169 
170 #define	ZIO_FLAG_AGG_INHERIT	(ZIO_FLAG_CANFAIL - 1)
171 
172 	/*
173 	 * Flags inherited by ddt, gang, and vdev children.
174 	 */
175 	ZIO_FLAG_CANFAIL	= 1 << 7,	/* must be first for INHERIT */
176 	ZIO_FLAG_SPECULATIVE	= 1 << 8,
177 	ZIO_FLAG_CONFIG_WRITER	= 1 << 9,
178 	ZIO_FLAG_DONT_RETRY	= 1 << 10,
179 	ZIO_FLAG_DONT_CACHE	= 1 << 11,
180 	ZIO_FLAG_NODATA		= 1 << 12,
181 	ZIO_FLAG_INDUCE_DAMAGE	= 1 << 13,
182 
183 #define	ZIO_FLAG_DDT_INHERIT	(ZIO_FLAG_IO_RETRY - 1)
184 #define	ZIO_FLAG_GANG_INHERIT	(ZIO_FLAG_IO_RETRY - 1)
185 
186 	/*
187 	 * Flags inherited by vdev children.
188 	 */
189 	ZIO_FLAG_IO_RETRY	= 1 << 14,	/* must be first for INHERIT */
190 	ZIO_FLAG_PROBE		= 1 << 15,
191 	ZIO_FLAG_TRYHARD	= 1 << 16,
192 	ZIO_FLAG_OPTIONAL	= 1 << 17,
193 
194 #define	ZIO_FLAG_VDEV_INHERIT	(ZIO_FLAG_DONT_QUEUE - 1)
195 
196 	/*
197 	 * Flags not inherited by any children.
198 	 */
199 	ZIO_FLAG_DONT_QUEUE	= 1 << 18,	/* must be first for INHERIT */
200 	ZIO_FLAG_DONT_PROPAGATE	= 1 << 19,
201 	ZIO_FLAG_IO_BYPASS	= 1 << 20,
202 	ZIO_FLAG_IO_REWRITE	= 1 << 21,
203 	ZIO_FLAG_RAW		= 1 << 22,
204 	ZIO_FLAG_GANG_CHILD	= 1 << 23,
205 	ZIO_FLAG_DDT_CHILD	= 1 << 24,
206 	ZIO_FLAG_GODFATHER	= 1 << 25,
207 	ZIO_FLAG_NOPWRITE	= 1 << 26,
208 	ZIO_FLAG_REEXECUTED	= 1 << 27,
209 	ZIO_FLAG_DELEGATED	= 1 << 28,
210 };
211 
212 #define	ZIO_FLAG_MUSTSUCCEED		0
213 
214 #define	ZIO_DDT_CHILD_FLAGS(zio)				\
215 	(((zio)->io_flags & ZIO_FLAG_DDT_INHERIT) |		\
216 	ZIO_FLAG_DDT_CHILD | ZIO_FLAG_CANFAIL)
217 
218 #define	ZIO_GANG_CHILD_FLAGS(zio)				\
219 	(((zio)->io_flags & ZIO_FLAG_GANG_INHERIT) |		\
220 	ZIO_FLAG_GANG_CHILD | ZIO_FLAG_CANFAIL)
221 
222 #define	ZIO_VDEV_CHILD_FLAGS(zio)				\
223 	(((zio)->io_flags & ZIO_FLAG_VDEV_INHERIT) |		\
224 	ZIO_FLAG_CANFAIL)
225 
226 enum zio_child {
227 	ZIO_CHILD_VDEV = 0,
228 	ZIO_CHILD_GANG,
229 	ZIO_CHILD_DDT,
230 	ZIO_CHILD_LOGICAL,
231 	ZIO_CHILD_TYPES
232 };
233 
234 enum zio_wait_type {
235 	ZIO_WAIT_READY = 0,
236 	ZIO_WAIT_DONE,
237 	ZIO_WAIT_TYPES
238 };
239 
240 /*
241  * We'll take the unused errnos, 'EBADE' and 'EBADR' (from the Convergent
242  * graveyard) to indicate checksum errors and fragmentation.
243  */
244 #define	ECKSUM	EBADE
245 #define	EFRAGS	EBADR
246 
247 typedef void zio_done_func_t(zio_t *zio);
248 
249 extern const char *zio_type_name[ZIO_TYPES];
250 
251 /*
252  * A bookmark is a four-tuple <objset, object, level, blkid> that uniquely
253  * identifies any block in the pool.  By convention, the meta-objset (MOS)
254  * is objset 0, and the meta-dnode is object 0.  This covers all blocks
255  * except root blocks and ZIL blocks, which are defined as follows:
256  *
257  * Root blocks (objset_phys_t) are object 0, level -1:  <objset, 0, -1, 0>.
258  * ZIL blocks are bookmarked <objset, 0, -2, blkid == ZIL sequence number>.
259  * dmu_sync()ed ZIL data blocks are bookmarked <objset, object, -2, blkid>.
260  *
261  * Note: this structure is called a bookmark because its original purpose
262  * was to remember where to resume a pool-wide traverse.
263  *
264  * Note: this structure is passed between userland and the kernel, and is
265  * stored on disk (by virtue of being incorporated into other on-disk
266  * structures, e.g. dsl_scan_phys_t).
267  */
268 typedef struct zbookmark_phys {
269 	uint64_t	zb_objset;
270 	uint64_t	zb_object;
271 	int64_t		zb_level;
272 	uint64_t	zb_blkid;
273 } zbookmark_phys_t;
274 
275 #define	SET_BOOKMARK(zb, objset, object, level, blkid)  \
276 {                                                       \
277 	(zb)->zb_objset = objset;                       \
278 	(zb)->zb_object = object;                       \
279 	(zb)->zb_level = level;                         \
280 	(zb)->zb_blkid = blkid;                         \
281 }
282 
283 #define	ZB_DESTROYED_OBJSET	(-1ULL)
284 
285 #define	ZB_ROOT_OBJECT		(0ULL)
286 #define	ZB_ROOT_LEVEL		(-1LL)
287 #define	ZB_ROOT_BLKID		(0ULL)
288 
289 #define	ZB_ZIL_OBJECT		(0ULL)
290 #define	ZB_ZIL_LEVEL		(-2LL)
291 
292 #define	ZB_IS_ZERO(zb)						\
293 	((zb)->zb_objset == 0 && (zb)->zb_object == 0 &&	\
294 	(zb)->zb_level == 0 && (zb)->zb_blkid == 0)
295 #define	ZB_IS_ROOT(zb)				\
296 	((zb)->zb_object == ZB_ROOT_OBJECT &&	\
297 	(zb)->zb_level == ZB_ROOT_LEVEL &&	\
298 	(zb)->zb_blkid == ZB_ROOT_BLKID)
299 
300 typedef struct zio_prop {
301 	enum zio_checksum	zp_checksum;
302 	enum zio_compress	zp_compress;
303 	dmu_object_type_t	zp_type;
304 	uint8_t			zp_level;
305 	uint8_t			zp_copies;
306 	boolean_t		zp_dedup;
307 	boolean_t		zp_dedup_verify;
308 	boolean_t		zp_nopwrite;
309 } zio_prop_t;
310 
311 typedef struct zio_cksum_report zio_cksum_report_t;
312 
313 typedef void zio_cksum_finish_f(zio_cksum_report_t *rep,
314     const void *good_data);
315 typedef void zio_cksum_free_f(void *cbdata, size_t size);
316 
317 struct zio_bad_cksum;				/* defined in zio_checksum.h */
318 struct dnode_phys;
319 
320 struct zio_cksum_report {
321 	struct zio_cksum_report *zcr_next;
322 	nvlist_t		*zcr_ereport;
323 	nvlist_t		*zcr_detector;
324 	void			*zcr_cbdata;
325 	size_t			zcr_cbinfo;	/* passed to zcr_free() */
326 	uint64_t		zcr_align;
327 	uint64_t		zcr_length;
328 	zio_cksum_finish_f	*zcr_finish;
329 	zio_cksum_free_f	*zcr_free;
330 
331 	/* internal use only */
332 	struct zio_bad_cksum	*zcr_ckinfo;	/* information from failure */
333 };
334 
335 typedef void zio_vsd_cksum_report_f(zio_t *zio, zio_cksum_report_t *zcr,
336     void *arg);
337 
338 zio_vsd_cksum_report_f	zio_vsd_default_cksum_report;
339 
340 typedef struct zio_vsd_ops {
341 	zio_done_func_t		*vsd_free;
342 	zio_vsd_cksum_report_f	*vsd_cksum_report;
343 } zio_vsd_ops_t;
344 
345 typedef struct zio_gang_node {
346 	zio_gbh_phys_t		*gn_gbh;
347 	struct zio_gang_node	*gn_child[SPA_GBH_NBLKPTRS];
348 } zio_gang_node_t;
349 
350 typedef zio_t *zio_gang_issue_func_t(zio_t *zio, blkptr_t *bp,
351     zio_gang_node_t *gn, void *data);
352 
353 typedef void zio_transform_func_t(zio_t *zio, void *data, uint64_t size);
354 
355 typedef struct zio_transform {
356 	void			*zt_orig_data;
357 	uint64_t		zt_orig_size;
358 	uint64_t		zt_bufsize;
359 	zio_transform_func_t	*zt_transform;
360 	struct zio_transform	*zt_next;
361 } zio_transform_t;
362 
363 typedef int zio_pipe_stage_t(zio_t *zio);
364 
365 /*
366  * The io_reexecute flags are distinct from io_flags because the child must
367  * be able to propagate them to the parent.  The normal io_flags are local
368  * to the zio, not protected by any lock, and not modifiable by children;
369  * the reexecute flags are protected by io_lock, modifiable by children,
370  * and always propagated -- even when ZIO_FLAG_DONT_PROPAGATE is set.
371  */
372 #define	ZIO_REEXECUTE_NOW	0x01
373 #define	ZIO_REEXECUTE_SUSPEND	0x02
374 
375 typedef struct zio_link {
376 	zio_t		*zl_parent;
377 	zio_t		*zl_child;
378 	list_node_t	zl_parent_node;
379 	list_node_t	zl_child_node;
380 } zio_link_t;
381 
382 struct zio {
383 	/* Core information about this I/O */
384 	zbookmark_phys_t	io_bookmark;
385 	zio_prop_t	io_prop;
386 	zio_type_t	io_type;
387 	enum zio_child	io_child_type;
388 	int		io_cmd;
389 	zio_priority_t	io_priority;
390 	uint8_t		io_reexecute;
391 	uint8_t		io_state[ZIO_WAIT_TYPES];
392 	uint64_t	io_txg;
393 	spa_t		*io_spa;
394 	blkptr_t	*io_bp;
395 	blkptr_t	*io_bp_override;
396 	blkptr_t	io_bp_copy;
397 	list_t		io_parent_list;
398 	list_t		io_child_list;
399 	zio_link_t	*io_walk_link;
400 	zio_t		*io_logical;
401 	zio_transform_t *io_transform_stack;
402 
403 	/* Callback info */
404 	zio_done_func_t	*io_ready;
405 	zio_done_func_t	*io_physdone;
406 	zio_done_func_t	*io_done;
407 	void		*io_private;
408 	int64_t		io_prev_space_delta;	/* DMU private */
409 	blkptr_t	io_bp_orig;
410 
411 	/* Data represented by this I/O */
412 	void		*io_data;
413 	void		*io_orig_data;
414 	uint64_t	io_size;
415 	uint64_t	io_orig_size;
416 
417 	/* Stuff for the vdev stack */
418 	vdev_t		*io_vd;
419 	void		*io_vsd;
420 	const zio_vsd_ops_t *io_vsd_ops;
421 
422 	uint64_t	io_offset;
423 	hrtime_t	io_timestamp;
424 	avl_node_t	io_queue_node;
425 
426 	/* Internal pipeline state */
427 	enum zio_flag	io_flags;
428 	enum zio_stage	io_stage;
429 	enum zio_stage	io_pipeline;
430 	enum zio_flag	io_orig_flags;
431 	enum zio_stage	io_orig_stage;
432 	enum zio_stage	io_orig_pipeline;
433 	int		io_error;
434 	int		io_child_error[ZIO_CHILD_TYPES];
435 	uint64_t	io_children[ZIO_CHILD_TYPES][ZIO_WAIT_TYPES];
436 	uint64_t	io_child_count;
437 	uint64_t	io_phys_children;
438 	uint64_t	io_parent_count;
439 	uint64_t	*io_stall;
440 	zio_t		*io_gang_leader;
441 	zio_gang_node_t	*io_gang_tree;
442 	void		*io_executor;
443 	void		*io_waiter;
444 	kmutex_t	io_lock;
445 	kcondvar_t	io_cv;
446 
447 	/* FMA state */
448 	zio_cksum_report_t *io_cksum_report;
449 	uint64_t	io_ena;
450 
451 	/* Taskq dispatching state */
452 	taskq_ent_t	io_tqent;
453 };
454 
455 extern zio_t *zio_null(zio_t *pio, spa_t *spa, vdev_t *vd,
456     zio_done_func_t *done, void *private, enum zio_flag flags);
457 
458 extern zio_t *zio_root(spa_t *spa,
459     zio_done_func_t *done, void *private, enum zio_flag flags);
460 
461 extern zio_t *zio_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, void *data,
462     uint64_t size, zio_done_func_t *done, void *private,
463     zio_priority_t priority, enum zio_flag flags, const zbookmark_phys_t *zb);
464 
465 extern zio_t *zio_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
466     void *data, uint64_t size, const zio_prop_t *zp,
467     zio_done_func_t *ready, zio_done_func_t *physdone, zio_done_func_t *done,
468     void *private,
469     zio_priority_t priority, enum zio_flag flags, const zbookmark_phys_t *zb);
470 
471 extern zio_t *zio_rewrite(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
472     void *data, uint64_t size, zio_done_func_t *done, void *private,
473     zio_priority_t priority, enum zio_flag flags, zbookmark_phys_t *zb);
474 
475 extern void zio_write_override(zio_t *zio, blkptr_t *bp, int copies,
476     boolean_t nopwrite);
477 
478 extern void zio_free(spa_t *spa, uint64_t txg, const blkptr_t *bp);
479 
480 extern zio_t *zio_claim(zio_t *pio, spa_t *spa, uint64_t txg,
481     const blkptr_t *bp,
482     zio_done_func_t *done, void *private, enum zio_flag flags);
483 
484 extern zio_t *zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd,
485     zio_done_func_t *done, void *private, enum zio_flag flags);
486 
487 extern zio_t *zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset,
488     uint64_t size, void *data, int checksum,
489     zio_done_func_t *done, void *private, zio_priority_t priority,
490     enum zio_flag flags, boolean_t labels);
491 
492 extern zio_t *zio_write_phys(zio_t *pio, vdev_t *vd, uint64_t offset,
493     uint64_t size, void *data, int checksum,
494     zio_done_func_t *done, void *private, zio_priority_t priority,
495     enum zio_flag flags, boolean_t labels);
496 
497 extern zio_t *zio_free_sync(zio_t *pio, spa_t *spa, uint64_t txg,
498     const blkptr_t *bp, enum zio_flag flags);
499 
500 extern int zio_alloc_zil(spa_t *spa, uint64_t txg, blkptr_t *new_bp,
501     blkptr_t *old_bp, uint64_t size, boolean_t use_slog);
502 extern void zio_free_zil(spa_t *spa, uint64_t txg, blkptr_t *bp);
503 extern void zio_flush(zio_t *zio, vdev_t *vd);
504 extern void zio_shrink(zio_t *zio, uint64_t size);
505 
506 extern int zio_wait(zio_t *zio);
507 extern void zio_nowait(zio_t *zio);
508 extern void zio_execute(zio_t *zio);
509 extern void zio_interrupt(zio_t *zio);
510 
511 extern zio_t *zio_walk_parents(zio_t *cio);
512 extern zio_t *zio_walk_children(zio_t *pio);
513 extern zio_t *zio_unique_parent(zio_t *cio);
514 extern void zio_add_child(zio_t *pio, zio_t *cio);
515 
516 extern void *zio_buf_alloc(size_t size);
517 extern void zio_buf_free(void *buf, size_t size);
518 extern void *zio_data_buf_alloc(size_t size);
519 extern void zio_data_buf_free(void *buf, size_t size);
520 
521 extern void zio_resubmit_stage_async(void *);
522 
523 extern zio_t *zio_vdev_child_io(zio_t *zio, blkptr_t *bp, vdev_t *vd,
524     uint64_t offset, void *data, uint64_t size, int type,
525     zio_priority_t priority, enum zio_flag flags,
526     zio_done_func_t *done, void *private);
527 
528 extern zio_t *zio_vdev_delegated_io(vdev_t *vd, uint64_t offset,
529     void *data, uint64_t size, int type, zio_priority_t priority,
530     enum zio_flag flags, zio_done_func_t *done, void *private);
531 
532 extern void zio_vdev_io_bypass(zio_t *zio);
533 extern void zio_vdev_io_reissue(zio_t *zio);
534 extern void zio_vdev_io_redone(zio_t *zio);
535 
536 extern void zio_checksum_verified(zio_t *zio);
537 extern int zio_worst_error(int e1, int e2);
538 
539 extern enum zio_checksum zio_checksum_select(enum zio_checksum child,
540     enum zio_checksum parent);
541 extern enum zio_checksum zio_checksum_dedup_select(spa_t *spa,
542     enum zio_checksum child, enum zio_checksum parent);
543 extern enum zio_compress zio_compress_select(enum zio_compress child,
544     enum zio_compress parent);
545 
546 extern void zio_suspend(spa_t *spa, zio_t *zio);
547 extern int zio_resume(spa_t *spa);
548 extern void zio_resume_wait(spa_t *spa);
549 
550 /*
551  * Initial setup and teardown.
552  */
553 extern void zio_init(void);
554 extern void zio_fini(void);
555 
556 /*
557  * Fault injection
558  */
559 struct zinject_record;
560 extern uint32_t zio_injection_enabled;
561 extern int zio_inject_fault(char *name, int flags, int *id,
562     struct zinject_record *record);
563 extern int zio_inject_list_next(int *id, char *name, size_t buflen,
564     struct zinject_record *record);
565 extern int zio_clear_fault(int id);
566 extern void zio_handle_panic_injection(spa_t *spa, char *tag, uint64_t type);
567 extern int zio_handle_fault_injection(zio_t *zio, int error);
568 extern int zio_handle_device_injection(vdev_t *vd, zio_t *zio, int error);
569 extern int zio_handle_label_injection(zio_t *zio, int error);
570 extern void zio_handle_ignored_writes(zio_t *zio);
571 extern uint64_t zio_handle_io_delay(zio_t *zio);
572 
573 /*
574  * Checksum ereport functions
575  */
576 extern void zfs_ereport_start_checksum(spa_t *spa, vdev_t *vd, struct zio *zio,
577     uint64_t offset, uint64_t length, void *arg, struct zio_bad_cksum *info);
578 extern void zfs_ereport_finish_checksum(zio_cksum_report_t *report,
579     const void *good_data, const void *bad_data, boolean_t drop_if_identical);
580 
581 extern void zfs_ereport_send_interim_checksum(zio_cksum_report_t *report);
582 extern void zfs_ereport_free_checksum(zio_cksum_report_t *report);
583 
584 /* If we have the good data in hand, this function can be used */
585 extern void zfs_ereport_post_checksum(spa_t *spa, vdev_t *vd,
586     struct zio *zio, uint64_t offset, uint64_t length,
587     const void *good_data, const void *bad_data, struct zio_bad_cksum *info);
588 
589 /* Called from spa_sync(), but primarily an injection handler */
590 extern void spa_handle_ignored_writes(spa_t *spa);
591 
592 /* zbookmark_phys functions */
593 boolean_t zbookmark_is_before(const struct dnode_phys *dnp,
594     const zbookmark_phys_t *zb1, const zbookmark_phys_t *zb2);
595 
596 #ifdef	__cplusplus
597 }
598 #endif
599 
600 #endif	/* _ZIO_H */
601