xref: /titanic_41/usr/src/uts/common/fs/zfs/sys/zio.h (revision b1fa6326238973aeaf12c34fcda75985b6c06be1)
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 by Delphix. All rights reserved.
26  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
27  */
28 
29 #ifndef _ZIO_H
30 #define	_ZIO_H
31 
32 #include <sys/zfs_context.h>
33 #include <sys/spa.h>
34 #include <sys/txg.h>
35 #include <sys/avl.h>
36 #include <sys/fs/zfs.h>
37 #include <sys/zio_impl.h>
38 
39 #ifdef	__cplusplus
40 extern "C" {
41 #endif
42 
43 /*
44  * Embedded checksum
45  */
46 #define	ZEC_MAGIC	0x210da7ab10c7a11ULL
47 
48 typedef struct zio_eck {
49 	uint64_t	zec_magic;	/* for validation, endianness	*/
50 	zio_cksum_t	zec_cksum;	/* 256-bit checksum		*/
51 } zio_eck_t;
52 
53 /*
54  * Gang block headers are self-checksumming and contain an array
55  * of block pointers.
56  */
57 #define	SPA_GANGBLOCKSIZE	SPA_MINBLOCKSIZE
58 #define	SPA_GBH_NBLKPTRS	((SPA_GANGBLOCKSIZE - \
59 	sizeof (zio_eck_t)) / sizeof (blkptr_t))
60 #define	SPA_GBH_FILLER		((SPA_GANGBLOCKSIZE - \
61 	sizeof (zio_eck_t) - \
62 	(SPA_GBH_NBLKPTRS * sizeof (blkptr_t))) /\
63 	sizeof (uint64_t))
64 
65 typedef struct zio_gbh {
66 	blkptr_t		zg_blkptr[SPA_GBH_NBLKPTRS];
67 	uint64_t		zg_filler[SPA_GBH_FILLER];
68 	zio_eck_t		zg_tail;
69 } zio_gbh_phys_t;
70 
71 enum zio_checksum {
72 	ZIO_CHECKSUM_INHERIT = 0,
73 	ZIO_CHECKSUM_ON,
74 	ZIO_CHECKSUM_OFF,
75 	ZIO_CHECKSUM_LABEL,
76 	ZIO_CHECKSUM_GANG_HEADER,
77 	ZIO_CHECKSUM_ZILOG,
78 	ZIO_CHECKSUM_FLETCHER_2,
79 	ZIO_CHECKSUM_FLETCHER_4,
80 	ZIO_CHECKSUM_SHA256,
81 	ZIO_CHECKSUM_ZILOG2,
82 	ZIO_CHECKSUM_FUNCTIONS
83 };
84 
85 #define	ZIO_CHECKSUM_ON_VALUE	ZIO_CHECKSUM_FLETCHER_4
86 #define	ZIO_CHECKSUM_DEFAULT	ZIO_CHECKSUM_ON
87 
88 #define	ZIO_CHECKSUM_MASK	0xffULL
89 #define	ZIO_CHECKSUM_VERIFY	(1 << 8)
90 
91 #define	ZIO_DEDUPCHECKSUM	ZIO_CHECKSUM_SHA256
92 #define	ZIO_DEDUPDITTO_MIN	100
93 
94 enum zio_compress {
95 	ZIO_COMPRESS_INHERIT = 0,
96 	ZIO_COMPRESS_ON,
97 	ZIO_COMPRESS_OFF,
98 	ZIO_COMPRESS_LZJB,
99 	ZIO_COMPRESS_EMPTY,
100 	ZIO_COMPRESS_GZIP_1,
101 	ZIO_COMPRESS_GZIP_2,
102 	ZIO_COMPRESS_GZIP_3,
103 	ZIO_COMPRESS_GZIP_4,
104 	ZIO_COMPRESS_GZIP_5,
105 	ZIO_COMPRESS_GZIP_6,
106 	ZIO_COMPRESS_GZIP_7,
107 	ZIO_COMPRESS_GZIP_8,
108 	ZIO_COMPRESS_GZIP_9,
109 	ZIO_COMPRESS_ZLE,
110 	ZIO_COMPRESS_LZ4,
111 	ZIO_COMPRESS_FUNCTIONS
112 };
113 
114 /* N.B. when altering this value, also change BOOTFS_COMPRESS_VALID below */
115 #define	ZIO_COMPRESS_ON_VALUE	ZIO_COMPRESS_LZJB
116 #define	ZIO_COMPRESS_DEFAULT	ZIO_COMPRESS_OFF
117 
118 #define	BOOTFS_COMPRESS_VALID(compress)			\
119 	((compress) == ZIO_COMPRESS_LZJB ||		\
120 	(compress) == ZIO_COMPRESS_LZ4 ||		\
121 	((compress) == ZIO_COMPRESS_ON &&		\
122 	ZIO_COMPRESS_ON_VALUE == ZIO_COMPRESS_LZJB) ||	\
123 	(compress) == ZIO_COMPRESS_OFF)
124 
125 #define	ZIO_FAILURE_MODE_WAIT		0
126 #define	ZIO_FAILURE_MODE_CONTINUE	1
127 #define	ZIO_FAILURE_MODE_PANIC		2
128 
129 #define	ZIO_PRIORITY_NOW		(zio_priority_table[0])
130 #define	ZIO_PRIORITY_SYNC_READ		(zio_priority_table[1])
131 #define	ZIO_PRIORITY_SYNC_WRITE		(zio_priority_table[2])
132 #define	ZIO_PRIORITY_LOG_WRITE		(zio_priority_table[3])
133 #define	ZIO_PRIORITY_CACHE_FILL		(zio_priority_table[4])
134 #define	ZIO_PRIORITY_AGG		(zio_priority_table[5])
135 #define	ZIO_PRIORITY_FREE		(zio_priority_table[6])
136 #define	ZIO_PRIORITY_ASYNC_WRITE	(zio_priority_table[7])
137 #define	ZIO_PRIORITY_ASYNC_READ		(zio_priority_table[8])
138 #define	ZIO_PRIORITY_RESILVER		(zio_priority_table[9])
139 #define	ZIO_PRIORITY_SCRUB		(zio_priority_table[10])
140 #define	ZIO_PRIORITY_DDT_PREFETCH	(zio_priority_table[11])
141 #define	ZIO_PRIORITY_TABLE_SIZE		12
142 
143 #define	ZIO_PIPELINE_CONTINUE		0x100
144 #define	ZIO_PIPELINE_STOP		0x101
145 
146 enum zio_flag {
147 	/*
148 	 * Flags inherited by gang, ddt, and vdev children,
149 	 * and that must be equal for two zios to aggregate
150 	 */
151 	ZIO_FLAG_DONT_AGGREGATE	= 1 << 0,
152 	ZIO_FLAG_IO_REPAIR	= 1 << 1,
153 	ZIO_FLAG_SELF_HEAL	= 1 << 2,
154 	ZIO_FLAG_RESILVER	= 1 << 3,
155 	ZIO_FLAG_SCRUB		= 1 << 4,
156 	ZIO_FLAG_SCAN_THREAD	= 1 << 5,
157 
158 #define	ZIO_FLAG_AGG_INHERIT	(ZIO_FLAG_CANFAIL - 1)
159 
160 	/*
161 	 * Flags inherited by ddt, gang, and vdev children.
162 	 */
163 	ZIO_FLAG_CANFAIL	= 1 << 6,	/* must be first for INHERIT */
164 	ZIO_FLAG_SPECULATIVE	= 1 << 7,
165 	ZIO_FLAG_CONFIG_WRITER	= 1 << 8,
166 	ZIO_FLAG_DONT_RETRY	= 1 << 9,
167 	ZIO_FLAG_DONT_CACHE	= 1 << 10,
168 	ZIO_FLAG_NODATA		= 1 << 11,
169 	ZIO_FLAG_INDUCE_DAMAGE	= 1 << 12,
170 
171 #define	ZIO_FLAG_DDT_INHERIT	(ZIO_FLAG_IO_RETRY - 1)
172 #define	ZIO_FLAG_GANG_INHERIT	(ZIO_FLAG_IO_RETRY - 1)
173 
174 	/*
175 	 * Flags inherited by vdev children.
176 	 */
177 	ZIO_FLAG_IO_RETRY	= 1 << 13,	/* must be first for INHERIT */
178 	ZIO_FLAG_PROBE		= 1 << 14,
179 	ZIO_FLAG_TRYHARD	= 1 << 15,
180 	ZIO_FLAG_OPTIONAL	= 1 << 16,
181 
182 #define	ZIO_FLAG_VDEV_INHERIT	(ZIO_FLAG_DONT_QUEUE - 1)
183 
184 	/*
185 	 * Flags not inherited by any children.
186 	 */
187 	ZIO_FLAG_DONT_QUEUE	= 1 << 17,	/* must be first for INHERIT */
188 	ZIO_FLAG_DONT_PROPAGATE	= 1 << 18,
189 	ZIO_FLAG_IO_BYPASS	= 1 << 19,
190 	ZIO_FLAG_IO_REWRITE	= 1 << 20,
191 	ZIO_FLAG_RAW		= 1 << 21,
192 	ZIO_FLAG_GANG_CHILD	= 1 << 22,
193 	ZIO_FLAG_DDT_CHILD	= 1 << 23,
194 	ZIO_FLAG_GODFATHER	= 1 << 24,
195 	ZIO_FLAG_NOPWRITE	= 1 << 25,
196 	ZIO_FLAG_REEXECUTED	= 1 << 26,
197 };
198 
199 #define	ZIO_FLAG_MUSTSUCCEED		0
200 
201 #define	ZIO_DDT_CHILD_FLAGS(zio)				\
202 	(((zio)->io_flags & ZIO_FLAG_DDT_INHERIT) |		\
203 	ZIO_FLAG_DDT_CHILD | ZIO_FLAG_CANFAIL)
204 
205 #define	ZIO_GANG_CHILD_FLAGS(zio)				\
206 	(((zio)->io_flags & ZIO_FLAG_GANG_INHERIT) |		\
207 	ZIO_FLAG_GANG_CHILD | ZIO_FLAG_CANFAIL)
208 
209 #define	ZIO_VDEV_CHILD_FLAGS(zio)				\
210 	(((zio)->io_flags & ZIO_FLAG_VDEV_INHERIT) |		\
211 	ZIO_FLAG_CANFAIL)
212 
213 enum zio_child {
214 	ZIO_CHILD_VDEV = 0,
215 	ZIO_CHILD_GANG,
216 	ZIO_CHILD_DDT,
217 	ZIO_CHILD_LOGICAL,
218 	ZIO_CHILD_TYPES
219 };
220 
221 enum zio_wait_type {
222 	ZIO_WAIT_READY = 0,
223 	ZIO_WAIT_DONE,
224 	ZIO_WAIT_TYPES
225 };
226 
227 /*
228  * We'll take the unused errnos, 'EBADE' and 'EBADR' (from the Convergent
229  * graveyard) to indicate checksum errors and fragmentation.
230  */
231 #define	ECKSUM	EBADE
232 #define	EFRAGS	EBADR
233 
234 typedef void zio_done_func_t(zio_t *zio);
235 
236 extern uint8_t zio_priority_table[ZIO_PRIORITY_TABLE_SIZE];
237 extern char *zio_type_name[ZIO_TYPES];
238 
239 /*
240  * A bookmark is a four-tuple <objset, object, level, blkid> that uniquely
241  * identifies any block in the pool.  By convention, the meta-objset (MOS)
242  * is objset 0, and the meta-dnode is object 0.  This covers all blocks
243  * except root blocks and ZIL blocks, which are defined as follows:
244  *
245  * Root blocks (objset_phys_t) are object 0, level -1:  <objset, 0, -1, 0>.
246  * ZIL blocks are bookmarked <objset, 0, -2, blkid == ZIL sequence number>.
247  * dmu_sync()ed ZIL data blocks are bookmarked <objset, object, -2, blkid>.
248  *
249  * Note: this structure is called a bookmark because its original purpose
250  * was to remember where to resume a pool-wide traverse.
251  *
252  * Note: this structure is passed between userland and the kernel.
253  * Therefore it must not change size or alignment between 32/64 bit
254  * compilation options.
255  */
256 typedef struct zbookmark {
257 	uint64_t	zb_objset;
258 	uint64_t	zb_object;
259 	int64_t		zb_level;
260 	uint64_t	zb_blkid;
261 } zbookmark_t;
262 
263 #define	SET_BOOKMARK(zb, objset, object, level, blkid)  \
264 {                                                       \
265 	(zb)->zb_objset = objset;                       \
266 	(zb)->zb_object = object;                       \
267 	(zb)->zb_level = level;                         \
268 	(zb)->zb_blkid = blkid;                         \
269 }
270 
271 #define	ZB_DESTROYED_OBJSET	(-1ULL)
272 
273 #define	ZB_ROOT_OBJECT		(0ULL)
274 #define	ZB_ROOT_LEVEL		(-1LL)
275 #define	ZB_ROOT_BLKID		(0ULL)
276 
277 #define	ZB_ZIL_OBJECT		(0ULL)
278 #define	ZB_ZIL_LEVEL		(-2LL)
279 
280 #define	ZB_IS_ZERO(zb)						\
281 	((zb)->zb_objset == 0 && (zb)->zb_object == 0 &&	\
282 	(zb)->zb_level == 0 && (zb)->zb_blkid == 0)
283 #define	ZB_IS_ROOT(zb)				\
284 	((zb)->zb_object == ZB_ROOT_OBJECT &&	\
285 	(zb)->zb_level == ZB_ROOT_LEVEL &&	\
286 	(zb)->zb_blkid == ZB_ROOT_BLKID)
287 
288 typedef struct zio_prop {
289 	enum zio_checksum	zp_checksum;
290 	enum zio_compress	zp_compress;
291 	dmu_object_type_t	zp_type;
292 	uint8_t			zp_level;
293 	uint8_t			zp_copies;
294 	boolean_t		zp_dedup;
295 	boolean_t		zp_dedup_verify;
296 	boolean_t		zp_nopwrite;
297 } zio_prop_t;
298 
299 typedef struct zio_cksum_report zio_cksum_report_t;
300 
301 typedef void zio_cksum_finish_f(zio_cksum_report_t *rep,
302     const void *good_data);
303 typedef void zio_cksum_free_f(void *cbdata, size_t size);
304 
305 struct zio_bad_cksum;				/* defined in zio_checksum.h */
306 struct dnode_phys;
307 
308 struct zio_cksum_report {
309 	struct zio_cksum_report *zcr_next;
310 	nvlist_t		*zcr_ereport;
311 	nvlist_t		*zcr_detector;
312 	void			*zcr_cbdata;
313 	size_t			zcr_cbinfo;	/* passed to zcr_free() */
314 	uint64_t		zcr_align;
315 	uint64_t		zcr_length;
316 	zio_cksum_finish_f	*zcr_finish;
317 	zio_cksum_free_f	*zcr_free;
318 
319 	/* internal use only */
320 	struct zio_bad_cksum	*zcr_ckinfo;	/* information from failure */
321 };
322 
323 typedef void zio_vsd_cksum_report_f(zio_t *zio, zio_cksum_report_t *zcr,
324     void *arg);
325 
326 zio_vsd_cksum_report_f	zio_vsd_default_cksum_report;
327 
328 typedef struct zio_vsd_ops {
329 	zio_done_func_t		*vsd_free;
330 	zio_vsd_cksum_report_f	*vsd_cksum_report;
331 } zio_vsd_ops_t;
332 
333 typedef struct zio_gang_node {
334 	zio_gbh_phys_t		*gn_gbh;
335 	struct zio_gang_node	*gn_child[SPA_GBH_NBLKPTRS];
336 } zio_gang_node_t;
337 
338 typedef zio_t *zio_gang_issue_func_t(zio_t *zio, blkptr_t *bp,
339     zio_gang_node_t *gn, void *data);
340 
341 typedef void zio_transform_func_t(zio_t *zio, void *data, uint64_t size);
342 
343 typedef struct zio_transform {
344 	void			*zt_orig_data;
345 	uint64_t		zt_orig_size;
346 	uint64_t		zt_bufsize;
347 	zio_transform_func_t	*zt_transform;
348 	struct zio_transform	*zt_next;
349 } zio_transform_t;
350 
351 typedef int zio_pipe_stage_t(zio_t *zio);
352 
353 /*
354  * The io_reexecute flags are distinct from io_flags because the child must
355  * be able to propagate them to the parent.  The normal io_flags are local
356  * to the zio, not protected by any lock, and not modifiable by children;
357  * the reexecute flags are protected by io_lock, modifiable by children,
358  * and always propagated -- even when ZIO_FLAG_DONT_PROPAGATE is set.
359  */
360 #define	ZIO_REEXECUTE_NOW	0x01
361 #define	ZIO_REEXECUTE_SUSPEND	0x02
362 
363 typedef struct zio_link {
364 	zio_t		*zl_parent;
365 	zio_t		*zl_child;
366 	list_node_t	zl_parent_node;
367 	list_node_t	zl_child_node;
368 } zio_link_t;
369 
370 struct zio {
371 	/* Core information about this I/O */
372 	zbookmark_t	io_bookmark;
373 	zio_prop_t	io_prop;
374 	zio_type_t	io_type;
375 	enum zio_child	io_child_type;
376 	int		io_cmd;
377 	uint8_t		io_priority;
378 	uint8_t		io_reexecute;
379 	uint8_t		io_state[ZIO_WAIT_TYPES];
380 	uint64_t	io_txg;
381 	spa_t		*io_spa;
382 	blkptr_t	*io_bp;
383 	blkptr_t	*io_bp_override;
384 	blkptr_t	io_bp_copy;
385 	list_t		io_parent_list;
386 	list_t		io_child_list;
387 	zio_link_t	*io_walk_link;
388 	zio_t		*io_logical;
389 	zio_transform_t *io_transform_stack;
390 
391 	/* Callback info */
392 	zio_done_func_t	*io_ready;
393 	zio_done_func_t	*io_done;
394 	void		*io_private;
395 	int64_t		io_prev_space_delta;	/* DMU private */
396 	blkptr_t	io_bp_orig;
397 
398 	/* Data represented by this I/O */
399 	void		*io_data;
400 	void		*io_orig_data;
401 	uint64_t	io_size;
402 	uint64_t	io_orig_size;
403 
404 	/* Stuff for the vdev stack */
405 	vdev_t		*io_vd;
406 	void		*io_vsd;
407 	const zio_vsd_ops_t *io_vsd_ops;
408 
409 	uint64_t	io_offset;
410 	uint64_t	io_deadline;
411 	hrtime_t	io_timestamp;
412 	avl_node_t	io_offset_node;
413 	avl_node_t	io_deadline_node;
414 	avl_tree_t	*io_vdev_tree;
415 
416 	/* Internal pipeline state */
417 	enum zio_flag	io_flags;
418 	enum zio_stage	io_stage;
419 	enum zio_stage	io_pipeline;
420 	enum zio_flag	io_orig_flags;
421 	enum zio_stage	io_orig_stage;
422 	enum zio_stage	io_orig_pipeline;
423 	int		io_error;
424 	int		io_child_error[ZIO_CHILD_TYPES];
425 	uint64_t	io_children[ZIO_CHILD_TYPES][ZIO_WAIT_TYPES];
426 	uint64_t	io_child_count;
427 	uint64_t	io_parent_count;
428 	uint64_t	*io_stall;
429 	zio_t		*io_gang_leader;
430 	zio_gang_node_t	*io_gang_tree;
431 	void		*io_executor;
432 	void		*io_waiter;
433 	kmutex_t	io_lock;
434 	kcondvar_t	io_cv;
435 
436 	/* FMA state */
437 	zio_cksum_report_t *io_cksum_report;
438 	uint64_t	io_ena;
439 
440 	/* Taskq dispatching state */
441 	taskq_ent_t	io_tqent;
442 };
443 
444 extern zio_t *zio_null(zio_t *pio, spa_t *spa, vdev_t *vd,
445     zio_done_func_t *done, void *private, enum zio_flag flags);
446 
447 extern zio_t *zio_root(spa_t *spa,
448     zio_done_func_t *done, void *private, enum zio_flag flags);
449 
450 extern zio_t *zio_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, void *data,
451     uint64_t size, zio_done_func_t *done, void *private,
452     int priority, enum zio_flag flags, const zbookmark_t *zb);
453 
454 extern zio_t *zio_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
455     void *data, uint64_t size, const zio_prop_t *zp,
456     zio_done_func_t *ready, zio_done_func_t *done, void *private,
457     int priority, enum zio_flag flags, const zbookmark_t *zb);
458 
459 extern zio_t *zio_rewrite(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
460     void *data, uint64_t size, zio_done_func_t *done, void *private,
461     int priority, enum zio_flag flags, zbookmark_t *zb);
462 
463 extern void zio_write_override(zio_t *zio, blkptr_t *bp, int copies,
464     boolean_t nopwrite);
465 
466 extern void zio_free(spa_t *spa, uint64_t txg, const blkptr_t *bp);
467 
468 extern zio_t *zio_claim(zio_t *pio, spa_t *spa, uint64_t txg,
469     const blkptr_t *bp,
470     zio_done_func_t *done, void *private, enum zio_flag flags);
471 
472 extern zio_t *zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd,
473     zio_done_func_t *done, void *private, int priority, enum zio_flag flags);
474 
475 extern zio_t *zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset,
476     uint64_t size, void *data, int checksum,
477     zio_done_func_t *done, void *private, int priority, enum zio_flag flags,
478     boolean_t labels);
479 
480 extern zio_t *zio_write_phys(zio_t *pio, vdev_t *vd, uint64_t offset,
481     uint64_t size, void *data, int checksum,
482     zio_done_func_t *done, void *private, int priority, enum zio_flag flags,
483     boolean_t labels);
484 
485 extern zio_t *zio_free_sync(zio_t *pio, spa_t *spa, uint64_t txg,
486     const blkptr_t *bp, enum zio_flag flags);
487 
488 extern int zio_alloc_zil(spa_t *spa, uint64_t txg, blkptr_t *new_bp,
489     blkptr_t *old_bp, uint64_t size, boolean_t use_slog);
490 extern void zio_free_zil(spa_t *spa, uint64_t txg, blkptr_t *bp);
491 extern void zio_flush(zio_t *zio, vdev_t *vd);
492 extern void zio_shrink(zio_t *zio, uint64_t size);
493 
494 extern int zio_wait(zio_t *zio);
495 extern void zio_nowait(zio_t *zio);
496 extern void zio_execute(zio_t *zio);
497 extern void zio_interrupt(zio_t *zio);
498 
499 extern zio_t *zio_walk_parents(zio_t *cio);
500 extern zio_t *zio_walk_children(zio_t *pio);
501 extern zio_t *zio_unique_parent(zio_t *cio);
502 extern void zio_add_child(zio_t *pio, zio_t *cio);
503 
504 extern void *zio_buf_alloc(size_t size);
505 extern void zio_buf_free(void *buf, size_t size);
506 extern void *zio_data_buf_alloc(size_t size);
507 extern void zio_data_buf_free(void *buf, size_t size);
508 
509 extern void zio_resubmit_stage_async(void *);
510 
511 extern zio_t *zio_vdev_child_io(zio_t *zio, blkptr_t *bp, vdev_t *vd,
512     uint64_t offset, void *data, uint64_t size, int type, int priority,
513     enum zio_flag flags, zio_done_func_t *done, void *private);
514 
515 extern zio_t *zio_vdev_delegated_io(vdev_t *vd, uint64_t offset,
516     void *data, uint64_t size, int type, int priority,
517     enum zio_flag flags, zio_done_func_t *done, void *private);
518 
519 extern void zio_vdev_io_bypass(zio_t *zio);
520 extern void zio_vdev_io_reissue(zio_t *zio);
521 extern void zio_vdev_io_redone(zio_t *zio);
522 
523 extern void zio_checksum_verified(zio_t *zio);
524 extern int zio_worst_error(int e1, int e2);
525 
526 extern enum zio_checksum zio_checksum_select(enum zio_checksum child,
527     enum zio_checksum parent);
528 extern enum zio_checksum zio_checksum_dedup_select(spa_t *spa,
529     enum zio_checksum child, enum zio_checksum parent);
530 extern enum zio_compress zio_compress_select(enum zio_compress child,
531     enum zio_compress parent);
532 
533 extern void zio_suspend(spa_t *spa, zio_t *zio);
534 extern int zio_resume(spa_t *spa);
535 extern void zio_resume_wait(spa_t *spa);
536 
537 /*
538  * Initial setup and teardown.
539  */
540 extern void zio_init(void);
541 extern void zio_fini(void);
542 
543 /*
544  * Fault injection
545  */
546 struct zinject_record;
547 extern uint32_t zio_injection_enabled;
548 extern int zio_inject_fault(char *name, int flags, int *id,
549     struct zinject_record *record);
550 extern int zio_inject_list_next(int *id, char *name, size_t buflen,
551     struct zinject_record *record);
552 extern int zio_clear_fault(int id);
553 extern void zio_handle_panic_injection(spa_t *spa, char *tag, uint64_t type);
554 extern int zio_handle_fault_injection(zio_t *zio, int error);
555 extern int zio_handle_device_injection(vdev_t *vd, zio_t *zio, int error);
556 extern int zio_handle_label_injection(zio_t *zio, int error);
557 extern void zio_handle_ignored_writes(zio_t *zio);
558 extern uint64_t zio_handle_io_delay(zio_t *zio);
559 
560 /*
561  * Checksum ereport functions
562  */
563 extern void zfs_ereport_start_checksum(spa_t *spa, vdev_t *vd, struct zio *zio,
564     uint64_t offset, uint64_t length, void *arg, struct zio_bad_cksum *info);
565 extern void zfs_ereport_finish_checksum(zio_cksum_report_t *report,
566     const void *good_data, const void *bad_data, boolean_t drop_if_identical);
567 
568 extern void zfs_ereport_send_interim_checksum(zio_cksum_report_t *report);
569 extern void zfs_ereport_free_checksum(zio_cksum_report_t *report);
570 
571 /* If we have the good data in hand, this function can be used */
572 extern void zfs_ereport_post_checksum(spa_t *spa, vdev_t *vd,
573     struct zio *zio, uint64_t offset, uint64_t length,
574     const void *good_data, const void *bad_data, struct zio_bad_cksum *info);
575 
576 /* Called from spa_sync(), but primarily an injection handler */
577 extern void spa_handle_ignored_writes(spa_t *spa);
578 
579 /* zbookmark functions */
580 boolean_t zbookmark_is_before(const struct dnode_phys *dnp,
581     const zbookmark_t *zb1, const zbookmark_t *zb2);
582 
583 #ifdef	__cplusplus
584 }
585 #endif
586 
587 #endif	/* _ZIO_H */
588