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         boolean_t               zp_zero_write;
 310 } zio_prop_t;
 311 
 312 typedef struct zio_cksum_report zio_cksum_report_t;
 313 
 314 typedef void zio_cksum_finish_f(zio_cksum_report_t *rep,
 315     const void *good_data);
 316 typedef void zio_cksum_free_f(void *cbdata, size_t size);
 317 
 318 struct zio_bad_cksum;                           /* defined in zio_checksum.h */
 319 struct dnode_phys;
 320 
 321 struct zio_cksum_report {
 322         struct zio_cksum_report *zcr_next;
 323         nvlist_t                *zcr_ereport;
 324         nvlist_t                *zcr_detector;
 325         void                    *zcr_cbdata;
 326         size_t                  zcr_cbinfo;     /* passed to zcr_free() */
 327         uint64_t                zcr_align;
 328         uint64_t                zcr_length;
 329         zio_cksum_finish_f      *zcr_finish;
 330         zio_cksum_free_f        *zcr_free;
 331 
 332         /* internal use only */
 333         struct zio_bad_cksum    *zcr_ckinfo;    /* information from failure */
 334 };
 335 
 336 typedef void zio_vsd_cksum_report_f(zio_t *zio, zio_cksum_report_t *zcr,
 337     void *arg);
 338 
 339 zio_vsd_cksum_report_f  zio_vsd_default_cksum_report;
 340 
 341 typedef struct zio_vsd_ops {
 342         zio_done_func_t         *vsd_free;
 343         zio_vsd_cksum_report_f  *vsd_cksum_report;
 344 } zio_vsd_ops_t;
 345 
 346 typedef struct zio_gang_node {
 347         zio_gbh_phys_t          *gn_gbh;
 348         struct zio_gang_node    *gn_child[SPA_GBH_NBLKPTRS];
 349 } zio_gang_node_t;
 350 
 351 typedef zio_t *zio_gang_issue_func_t(zio_t *zio, blkptr_t *bp,
 352     zio_gang_node_t *gn, void *data);
 353 
 354 typedef void zio_transform_func_t(zio_t *zio, void *data, uint64_t size);
 355 
 356 typedef struct zio_transform {
 357         void                    *zt_orig_data;
 358         uint64_t                zt_orig_size;
 359         uint64_t                zt_bufsize;
 360         zio_transform_func_t    *zt_transform;
 361         struct zio_transform    *zt_next;
 362 } zio_transform_t;
 363 
 364 typedef int zio_pipe_stage_t(zio_t *zio);
 365 
 366 /*
 367  * The io_reexecute flags are distinct from io_flags because the child must
 368  * be able to propagate them to the parent.  The normal io_flags are local
 369  * to the zio, not protected by any lock, and not modifiable by children;
 370  * the reexecute flags are protected by io_lock, modifiable by children,
 371  * and always propagated -- even when ZIO_FLAG_DONT_PROPAGATE is set.
 372  */
 373 #define ZIO_REEXECUTE_NOW       0x01
 374 #define ZIO_REEXECUTE_SUSPEND   0x02
 375 
 376 typedef struct zio_link {
 377         zio_t           *zl_parent;
 378         zio_t           *zl_child;
 379         list_node_t     zl_parent_node;
 380         list_node_t     zl_child_node;
 381 } zio_link_t;
 382 
 383 struct zio {
 384         /* Core information about this I/O */
 385         zbookmark_phys_t        io_bookmark;
 386         zio_prop_t      io_prop;
 387         zio_type_t      io_type;
 388         enum zio_child  io_child_type;
 389         int             io_cmd;
 390         zio_priority_t  io_priority;
 391         uint8_t         io_reexecute;
 392         uint8_t         io_state[ZIO_WAIT_TYPES];
 393         uint64_t        io_txg;
 394         spa_t           *io_spa;
 395         blkptr_t        *io_bp;
 396         blkptr_t        *io_bp_override;
 397         blkptr_t        io_bp_copy;
 398         list_t          io_parent_list;
 399         list_t          io_child_list;
 400         zio_link_t      *io_walk_link;
 401         zio_t           *io_logical;
 402         zio_transform_t *io_transform_stack;
 403 
 404         /* Callback info */
 405         zio_done_func_t *io_ready;
 406         zio_done_func_t *io_physdone;
 407         zio_done_func_t *io_done;
 408         void            *io_private;
 409         int64_t         io_prev_space_delta;    /* DMU private */
 410         blkptr_t        io_bp_orig;
 411 
 412         /* Data represented by this I/O */
 413         void            *io_data;
 414         void            *io_orig_data;
 415         uint64_t        io_size;
 416         uint64_t        io_orig_size;
 417 
 418         /* Stuff for the vdev stack */
 419         vdev_t          *io_vd;
 420         void            *io_vsd;
 421         const zio_vsd_ops_t *io_vsd_ops;
 422 
 423         uint64_t        io_offset;
 424         hrtime_t        io_timestamp;
 425         avl_node_t      io_queue_node;
 426 
 427         /* Internal pipeline state */
 428         enum zio_flag   io_flags;
 429         enum zio_stage  io_stage;
 430         enum zio_stage  io_pipeline;
 431         enum zio_flag   io_orig_flags;
 432         enum zio_stage  io_orig_stage;
 433         enum zio_stage  io_orig_pipeline;
 434         int             io_error;
 435         int             io_child_error[ZIO_CHILD_TYPES];
 436         uint64_t        io_children[ZIO_CHILD_TYPES][ZIO_WAIT_TYPES];
 437         uint64_t        io_child_count;
 438         uint64_t        io_phys_children;
 439         uint64_t        io_parent_count;
 440         uint64_t        *io_stall;
 441         zio_t           *io_gang_leader;
 442         zio_gang_node_t *io_gang_tree;
 443         void            *io_executor;
 444         void            *io_waiter;
 445         kmutex_t        io_lock;
 446         kcondvar_t      io_cv;
 447 
 448         /* FMA state */
 449         zio_cksum_report_t *io_cksum_report;
 450         uint64_t        io_ena;
 451 
 452         /* Taskq dispatching state */
 453         taskq_ent_t     io_tqent;
 454 };
 455 
 456 extern zio_t *zio_null(zio_t *pio, spa_t *spa, vdev_t *vd,
 457     zio_done_func_t *done, void *private, enum zio_flag flags);
 458 
 459 extern zio_t *zio_root(spa_t *spa,
 460     zio_done_func_t *done, void *private, enum zio_flag flags);
 461 
 462 extern zio_t *zio_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, void *data,
 463     uint64_t size, zio_done_func_t *done, void *private,
 464     zio_priority_t priority, enum zio_flag flags, const zbookmark_phys_t *zb);
 465 
 466 extern zio_t *zio_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
 467     void *data, uint64_t size, const zio_prop_t *zp,
 468     zio_done_func_t *ready, zio_done_func_t *physdone, zio_done_func_t *done,
 469     void *private,
 470     zio_priority_t priority, enum zio_flag flags, const zbookmark_phys_t *zb);
 471 
 472 extern zio_t *zio_rewrite(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
 473     void *data, uint64_t size, zio_done_func_t *done, void *private,
 474     zio_priority_t priority, enum zio_flag flags, zbookmark_phys_t *zb);
 475 
 476 extern void zio_write_override(zio_t *zio, blkptr_t *bp, int copies,
 477     boolean_t nopwrite);
 478 
 479 extern void zio_free(spa_t *spa, uint64_t txg, const blkptr_t *bp);
 480 
 481 extern zio_t *zio_claim(zio_t *pio, spa_t *spa, uint64_t txg,
 482     const blkptr_t *bp,
 483     zio_done_func_t *done, void *private, enum zio_flag flags);
 484 
 485 extern zio_t *zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd,
 486     zio_done_func_t *done, void *private, enum zio_flag flags);
 487 
 488 extern zio_t *zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset,
 489     uint64_t size, void *data, int checksum,
 490     zio_done_func_t *done, void *private, zio_priority_t priority,
 491     enum zio_flag flags, boolean_t labels);
 492 
 493 extern zio_t *zio_write_phys(zio_t *pio, vdev_t *vd, uint64_t offset,
 494     uint64_t size, void *data, int checksum,
 495     zio_done_func_t *done, void *private, zio_priority_t priority,
 496     enum zio_flag flags, boolean_t labels);
 497 
 498 extern zio_t *zio_free_sync(zio_t *pio, spa_t *spa, uint64_t txg,
 499     const blkptr_t *bp, enum zio_flag flags);
 500 
 501 extern int zio_alloc_zil(spa_t *spa, uint64_t txg, blkptr_t *new_bp,
 502     blkptr_t *old_bp, uint64_t size, boolean_t use_slog);
 503 extern void zio_free_zil(spa_t *spa, uint64_t txg, blkptr_t *bp);
 504 extern void zio_flush(zio_t *zio, vdev_t *vd);
 505 extern void zio_shrink(zio_t *zio, uint64_t size);
 506 
 507 extern int zio_wait(zio_t *zio);
 508 extern void zio_nowait(zio_t *zio);
 509 extern void zio_execute(zio_t *zio);
 510 extern void zio_interrupt(zio_t *zio);
 511 
 512 extern zio_t *zio_walk_parents(zio_t *cio);
 513 extern zio_t *zio_walk_children(zio_t *pio);
 514 extern zio_t *zio_unique_parent(zio_t *cio);
 515 extern void zio_add_child(zio_t *pio, zio_t *cio);
 516 
 517 extern void *zio_buf_alloc(size_t size);
 518 extern void zio_buf_free(void *buf, size_t size);
 519 extern void *zio_data_buf_alloc(size_t size);
 520 extern void zio_data_buf_free(void *buf, size_t size);
 521 
 522 extern void zio_resubmit_stage_async(void *);
 523 
 524 extern zio_t *zio_vdev_child_io(zio_t *zio, blkptr_t *bp, vdev_t *vd,
 525     uint64_t offset, void *data, uint64_t size, int type,
 526     zio_priority_t priority, enum zio_flag flags,
 527     zio_done_func_t *done, void *private);
 528 
 529 extern zio_t *zio_vdev_delegated_io(vdev_t *vd, uint64_t offset,
 530     void *data, uint64_t size, int type, zio_priority_t priority,
 531     enum zio_flag flags, zio_done_func_t *done, void *private);
 532 
 533 extern void zio_vdev_io_bypass(zio_t *zio);
 534 extern void zio_vdev_io_reissue(zio_t *zio);
 535 extern void zio_vdev_io_redone(zio_t *zio);
 536 
 537 extern void zio_checksum_verified(zio_t *zio);
 538 extern int zio_worst_error(int e1, int e2);
 539 
 540 extern enum zio_checksum zio_checksum_select(enum zio_checksum child,
 541     enum zio_checksum parent);
 542 extern enum zio_checksum zio_checksum_dedup_select(spa_t *spa,
 543     enum zio_checksum child, enum zio_checksum parent);
 544 extern enum zio_compress zio_compress_select(enum zio_compress child,
 545     enum zio_compress parent);
 546 
 547 extern void zio_suspend(spa_t *spa, zio_t *zio);
 548 extern int zio_resume(spa_t *spa);
 549 extern void zio_resume_wait(spa_t *spa);
 550 
 551 /*
 552  * Initial setup and teardown.
 553  */
 554 extern void zio_init(void);
 555 extern void zio_fini(void);
 556 
 557 /*
 558  * Fault injection
 559  */
 560 struct zinject_record;
 561 extern uint32_t zio_injection_enabled;
 562 extern int zio_inject_fault(char *name, int flags, int *id,
 563     struct zinject_record *record);
 564 extern int zio_inject_list_next(int *id, char *name, size_t buflen,
 565     struct zinject_record *record);
 566 extern int zio_clear_fault(int id);
 567 extern void zio_handle_panic_injection(spa_t *spa, char *tag, uint64_t type);
 568 extern int zio_handle_fault_injection(zio_t *zio, int error);
 569 extern int zio_handle_device_injection(vdev_t *vd, zio_t *zio, int error);
 570 extern int zio_handle_label_injection(zio_t *zio, int error);
 571 extern void zio_handle_ignored_writes(zio_t *zio);
 572 extern uint64_t zio_handle_io_delay(zio_t *zio);
 573 
 574 /*
 575  * Checksum ereport functions
 576  */
 577 extern void zfs_ereport_start_checksum(spa_t *spa, vdev_t *vd, struct zio *zio,
 578     uint64_t offset, uint64_t length, void *arg, struct zio_bad_cksum *info);
 579 extern void zfs_ereport_finish_checksum(zio_cksum_report_t *report,
 580     const void *good_data, const void *bad_data, boolean_t drop_if_identical);
 581 
 582 extern void zfs_ereport_send_interim_checksum(zio_cksum_report_t *report);
 583 extern void zfs_ereport_free_checksum(zio_cksum_report_t *report);
 584 
 585 /* If we have the good data in hand, this function can be used */
 586 extern void zfs_ereport_post_checksum(spa_t *spa, vdev_t *vd,
 587     struct zio *zio, uint64_t offset, uint64_t length,
 588     const void *good_data, const void *bad_data, struct zio_bad_cksum *info);
 589 
 590 /* Called from spa_sync(), but primarily an injection handler */
 591 extern void spa_handle_ignored_writes(spa_t *spa);
 592 
 593 /* zbookmark_phys functions */
 594 boolean_t zbookmark_is_before(const struct dnode_phys *dnp,
 595     const zbookmark_phys_t *zb1, const zbookmark_phys_t *zb2);
 596 
 597 #ifdef  __cplusplus
 598 }
 599 #endif
 600 
 601 #endif  /* _ZIO_H */