1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright (c) 2011, 2018 by Delphix. All rights reserved. 24 */ 25 26 #ifndef _SYS_VDEV_IMPL_H 27 #define _SYS_VDEV_IMPL_H 28 29 #include <sys/avl.h> 30 #include <sys/bpobj.h> 31 #include <sys/dmu.h> 32 #include <sys/metaslab.h> 33 #include <sys/nvpair.h> 34 #include <sys/space_map.h> 35 #include <sys/vdev.h> 36 #include <sys/dkio.h> 37 #include <sys/uberblock_impl.h> 38 #include <sys/vdev_indirect_mapping.h> 39 #include <sys/vdev_indirect_births.h> 40 #include <sys/vdev_removal.h> 41 42 #ifdef __cplusplus 43 extern "C" { 44 #endif 45 46 /* 47 * Virtual device descriptors. 48 * 49 * All storage pool operations go through the virtual device framework, 50 * which provides data replication and I/O scheduling. 51 */ 52 53 /* 54 * Forward declarations that lots of things need. 55 */ 56 typedef struct vdev_queue vdev_queue_t; 57 typedef struct vdev_cache vdev_cache_t; 58 typedef struct vdev_cache_entry vdev_cache_entry_t; 59 struct abd; 60 61 extern int zfs_vdev_queue_depth_pct; 62 extern int zfs_vdev_def_queue_depth; 63 extern uint32_t zfs_vdev_async_write_max_active; 64 65 /* 66 * Virtual device operations 67 */ 68 typedef int vdev_open_func_t(vdev_t *vd, uint64_t *size, uint64_t *max_size, 69 uint64_t *logical_ashift, uint64_t *physical_ashift); 70 typedef void vdev_close_func_t(vdev_t *vd); 71 typedef uint64_t vdev_asize_func_t(vdev_t *vd, uint64_t psize); 72 typedef void vdev_io_start_func_t(zio_t *zio); 73 typedef void vdev_io_done_func_t(zio_t *zio); 74 typedef void vdev_state_change_func_t(vdev_t *vd, int, int); 75 typedef boolean_t vdev_need_resilver_func_t(vdev_t *vd, uint64_t, size_t); 76 typedef void vdev_hold_func_t(vdev_t *vd); 77 typedef void vdev_rele_func_t(vdev_t *vd); 78 79 typedef void vdev_remap_cb_t(uint64_t inner_offset, vdev_t *vd, 80 uint64_t offset, uint64_t size, void *arg); 81 typedef void vdev_remap_func_t(vdev_t *vd, uint64_t offset, uint64_t size, 82 vdev_remap_cb_t callback, void *arg); 83 /* 84 * Given a target vdev, translates the logical range "in" to the physical 85 * range "res" 86 */ 87 typedef void vdev_xlation_func_t(vdev_t *cvd, const range_seg_t *in, 88 range_seg_t *res); 89 90 typedef struct vdev_ops { 91 vdev_open_func_t *vdev_op_open; 92 vdev_close_func_t *vdev_op_close; 93 vdev_asize_func_t *vdev_op_asize; 94 vdev_io_start_func_t *vdev_op_io_start; 95 vdev_io_done_func_t *vdev_op_io_done; 96 vdev_state_change_func_t *vdev_op_state_change; 97 vdev_need_resilver_func_t *vdev_op_need_resilver; 98 vdev_hold_func_t *vdev_op_hold; 99 vdev_rele_func_t *vdev_op_rele; 100 vdev_remap_func_t *vdev_op_remap; 101 /* 102 * For translating ranges from non-leaf vdevs (e.g. raidz) to leaves. 103 * Used when initializing vdevs. Isn't used by leaf ops. 104 */ 105 vdev_xlation_func_t *vdev_op_xlate; 106 char vdev_op_type[16]; 107 boolean_t vdev_op_leaf; 108 } vdev_ops_t; 109 110 /* 111 * Virtual device properties 112 */ 113 struct vdev_cache_entry { 114 struct abd *ve_abd; 115 uint64_t ve_offset; 116 uint64_t ve_lastused; 117 avl_node_t ve_offset_node; 118 avl_node_t ve_lastused_node; 119 uint32_t ve_hits; 120 uint16_t ve_missed_update; 121 zio_t *ve_fill_io; 122 }; 123 124 struct vdev_cache { 125 avl_tree_t vc_offset_tree; 126 avl_tree_t vc_lastused_tree; 127 kmutex_t vc_lock; 128 }; 129 130 typedef struct vdev_queue_class { 131 uint32_t vqc_active; 132 133 /* 134 * Sorted by offset or timestamp, depending on if the queue is 135 * LBA-ordered vs FIFO. 136 */ 137 avl_tree_t vqc_queued_tree; 138 } vdev_queue_class_t; 139 140 struct vdev_queue { 141 vdev_t *vq_vdev; 142 vdev_queue_class_t vq_class[ZIO_PRIORITY_NUM_QUEUEABLE]; 143 avl_tree_t vq_active_tree; 144 avl_tree_t vq_read_offset_tree; 145 avl_tree_t vq_write_offset_tree; 146 uint64_t vq_last_offset; 147 hrtime_t vq_io_complete_ts; /* time last i/o completed */ 148 kmutex_t vq_lock; 149 uint64_t vq_lastoffset; 150 }; 151 152 /* 153 * On-disk indirect vdev state. 154 * 155 * An indirect vdev is described exclusively in the MOS config of a pool. 156 * The config for an indirect vdev includes several fields, which are 157 * accessed in memory by a vdev_indirect_config_t. 158 */ 159 typedef struct vdev_indirect_config { 160 /* 161 * Object (in MOS) which contains the indirect mapping. This object 162 * contains an array of vdev_indirect_mapping_entry_phys_t ordered by 163 * vimep_src. The bonus buffer for this object is a 164 * vdev_indirect_mapping_phys_t. This object is allocated when a vdev 165 * removal is initiated. 166 * 167 * Note that this object can be empty if none of the data on the vdev 168 * has been copied yet. 169 */ 170 uint64_t vic_mapping_object; 171 172 /* 173 * Object (in MOS) which contains the birth times for the mapping 174 * entries. This object contains an array of 175 * vdev_indirect_birth_entry_phys_t sorted by vibe_offset. The bonus 176 * buffer for this object is a vdev_indirect_birth_phys_t. This object 177 * is allocated when a vdev removal is initiated. 178 * 179 * Note that this object can be empty if none of the vdev has yet been 180 * copied. 181 */ 182 uint64_t vic_births_object; 183 184 /* 185 * This is the vdev ID which was removed previous to this vdev, or 186 * UINT64_MAX if there are no previously removed vdevs. 187 */ 188 uint64_t vic_prev_indirect_vdev; 189 } vdev_indirect_config_t; 190 191 /* 192 * Virtual device descriptor 193 */ 194 struct vdev { 195 /* 196 * Common to all vdev types. 197 */ 198 uint64_t vdev_id; /* child number in vdev parent */ 199 uint64_t vdev_guid; /* unique ID for this vdev */ 200 uint64_t vdev_guid_sum; /* self guid + all child guids */ 201 uint64_t vdev_orig_guid; /* orig. guid prior to remove */ 202 uint64_t vdev_asize; /* allocatable device capacity */ 203 uint64_t vdev_min_asize; /* min acceptable asize */ 204 uint64_t vdev_max_asize; /* max acceptable asize */ 205 uint64_t vdev_ashift; /* block alignment shift */ 206 /* 207 * Logical block alignment shift 208 * 209 * The smallest sized/aligned I/O supported by the device. 210 */ 211 uint64_t vdev_logical_ashift; 212 /* 213 * Physical block alignment shift 214 * 215 * The device supports logical I/Os with vdev_logical_ashift 216 * size/alignment, but optimum performance will be achieved by 217 * aligning/sizing requests to vdev_physical_ashift. Smaller 218 * requests may be inflated or incur device level read-modify-write 219 * operations. 220 * 221 * May be 0 to indicate no preference (i.e. use vdev_logical_ashift). 222 */ 223 uint64_t vdev_physical_ashift; 224 uint64_t vdev_state; /* see VDEV_STATE_* #defines */ 225 uint64_t vdev_prevstate; /* used when reopening a vdev */ 226 vdev_ops_t *vdev_ops; /* vdev operations */ 227 spa_t *vdev_spa; /* spa for this vdev */ 228 void *vdev_tsd; /* type-specific data */ 229 vnode_t *vdev_name_vp; /* vnode for pathname */ 230 vnode_t *vdev_devid_vp; /* vnode for devid */ 231 vdev_t *vdev_top; /* top-level vdev */ 232 vdev_t *vdev_parent; /* parent vdev */ 233 vdev_t **vdev_child; /* array of children */ 234 uint64_t vdev_children; /* number of children */ 235 vdev_stat_t vdev_stat; /* virtual device statistics */ 236 boolean_t vdev_expanding; /* expand the vdev? */ 237 boolean_t vdev_reopening; /* reopen in progress? */ 238 boolean_t vdev_nonrot; /* true if solid state */ 239 int vdev_open_error; /* error on last open */ 240 kthread_t *vdev_open_thread; /* thread opening children */ 241 uint64_t vdev_crtxg; /* txg when top-level was added */ 242 243 /* 244 * Top-level vdev state. 245 */ 246 uint64_t vdev_ms_array; /* metaslab array object */ 247 uint64_t vdev_ms_shift; /* metaslab size shift */ 248 uint64_t vdev_ms_count; /* number of metaslabs */ 249 metaslab_group_t *vdev_mg; /* metaslab group */ 250 metaslab_t **vdev_ms; /* metaslab array */ 251 txg_list_t vdev_ms_list; /* per-txg dirty metaslab lists */ 252 txg_list_t vdev_dtl_list; /* per-txg dirty DTL lists */ 253 txg_node_t vdev_txg_node; /* per-txg dirty vdev linkage */ 254 boolean_t vdev_remove_wanted; /* async remove wanted? */ 255 boolean_t vdev_probe_wanted; /* async probe wanted? */ 256 list_node_t vdev_config_dirty_node; /* config dirty list */ 257 list_node_t vdev_state_dirty_node; /* state dirty list */ 258 uint64_t vdev_deflate_ratio; /* deflation ratio (x512) */ 259 uint64_t vdev_islog; /* is an intent log device */ 260 uint64_t vdev_removing; /* device is being removed? */ 261 boolean_t vdev_ishole; /* is a hole in the namespace */ 262 kmutex_t vdev_queue_lock; /* protects vdev_queue_depth */ 263 uint64_t vdev_top_zap; 264 265 /* pool checkpoint related */ 266 space_map_t *vdev_checkpoint_sm; /* contains reserved blocks */ 267 268 boolean_t vdev_initialize_exit_wanted; 269 vdev_initializing_state_t vdev_initialize_state; 270 kthread_t *vdev_initialize_thread; 271 /* Protects vdev_initialize_thread and vdev_initialize_state. */ 272 kmutex_t vdev_initialize_lock; 273 kcondvar_t vdev_initialize_cv; 274 uint64_t vdev_initialize_offset[TXG_SIZE]; 275 uint64_t vdev_initialize_last_offset; 276 range_tree_t *vdev_initialize_tree; /* valid while initializing */ 277 uint64_t vdev_initialize_bytes_est; 278 uint64_t vdev_initialize_bytes_done; 279 time_t vdev_initialize_action_time; /* start and end time */ 280 281 /* for limiting outstanding I/Os */ 282 kmutex_t vdev_initialize_io_lock; 283 kcondvar_t vdev_initialize_io_cv; 284 uint64_t vdev_initialize_inflight; 285 286 /* 287 * Values stored in the config for an indirect or removing vdev. 288 */ 289 vdev_indirect_config_t vdev_indirect_config; 290 291 /* 292 * The vdev_indirect_rwlock protects the vdev_indirect_mapping 293 * pointer from changing on indirect vdevs (when it is condensed). 294 * Note that removing (not yet indirect) vdevs have different 295 * access patterns (the mapping is not accessed from open context, 296 * e.g. from zio_read) and locking strategy (e.g. svr_lock). 297 */ 298 krwlock_t vdev_indirect_rwlock; 299 vdev_indirect_mapping_t *vdev_indirect_mapping; 300 vdev_indirect_births_t *vdev_indirect_births; 301 302 /* 303 * In memory data structures used to manage the obsolete sm, for 304 * indirect or removing vdevs. 305 * 306 * The vdev_obsolete_segments is the in-core record of the segments 307 * that are no longer referenced anywhere in the pool (due to 308 * being freed or remapped and not referenced by any snapshots). 309 * During a sync, segments are added to vdev_obsolete_segments 310 * via vdev_indirect_mark_obsolete(); at the end of each sync 311 * pass, this is appended to vdev_obsolete_sm via 312 * vdev_indirect_sync_obsolete(). The vdev_obsolete_lock 313 * protects against concurrent modifications of vdev_obsolete_segments 314 * from multiple zio threads. 315 */ 316 kmutex_t vdev_obsolete_lock; 317 range_tree_t *vdev_obsolete_segments; 318 space_map_t *vdev_obsolete_sm; 319 320 /* 321 * The queue depth parameters determine how many async writes are 322 * still pending (i.e. allocated but not yet issued to disk) per 323 * top-level (vdev_async_write_queue_depth) and the maximum allowed 324 * (vdev_max_async_write_queue_depth). These values only apply to 325 * top-level vdevs. 326 */ 327 uint64_t vdev_async_write_queue_depth; 328 uint64_t vdev_max_async_write_queue_depth; 329 330 /* 331 * Protects the vdev_scan_io_queue field itself as well as the 332 * structure's contents (when present). 333 */ 334 kmutex_t vdev_scan_io_queue_lock; 335 struct dsl_scan_io_queue *vdev_scan_io_queue; 336 337 /* 338 * Leaf vdev state. 339 */ 340 range_tree_t *vdev_dtl[DTL_TYPES]; /* dirty time logs */ 341 space_map_t *vdev_dtl_sm; /* dirty time log space map */ 342 txg_node_t vdev_dtl_node; /* per-txg dirty DTL linkage */ 343 uint64_t vdev_dtl_object; /* DTL object */ 344 uint64_t vdev_psize; /* physical device capacity */ 345 uint64_t vdev_wholedisk; /* true if this is a whole disk */ 346 uint64_t vdev_offline; /* persistent offline state */ 347 uint64_t vdev_faulted; /* persistent faulted state */ 348 uint64_t vdev_degraded; /* persistent degraded state */ 349 uint64_t vdev_removed; /* persistent removed state */ 350 uint64_t vdev_resilver_txg; /* persistent resilvering state */ 351 uint64_t vdev_nparity; /* number of parity devices for raidz */ 352 char *vdev_path; /* vdev path (if any) */ 353 char *vdev_devid; /* vdev devid (if any) */ 354 char *vdev_physpath; /* vdev device path (if any) */ 355 char *vdev_fru; /* physical FRU location */ 356 uint64_t vdev_not_present; /* not present during import */ 357 uint64_t vdev_unspare; /* unspare when resilvering done */ 358 boolean_t vdev_nowritecache; /* true if flushwritecache failed */ 359 boolean_t vdev_notrim; /* true if trim failed */ 360 boolean_t vdev_checkremove; /* temporary online test */ 361 boolean_t vdev_forcefault; /* force online fault */ 362 boolean_t vdev_splitting; /* split or repair in progress */ 363 boolean_t vdev_delayed_close; /* delayed device close? */ 364 boolean_t vdev_tmpoffline; /* device taken offline temporarily? */ 365 boolean_t vdev_detached; /* device detached? */ 366 boolean_t vdev_cant_read; /* vdev is failing all reads */ 367 boolean_t vdev_cant_write; /* vdev is failing all writes */ 368 boolean_t vdev_isspare; /* was a hot spare */ 369 boolean_t vdev_isl2cache; /* was a l2cache device */ 370 vdev_queue_t vdev_queue; /* I/O deadline schedule queue */ 371 vdev_cache_t vdev_cache; /* physical block cache */ 372 spa_aux_vdev_t *vdev_aux; /* for l2cache and spares vdevs */ 373 zio_t *vdev_probe_zio; /* root of current probe */ 374 vdev_aux_t vdev_label_aux; /* on-disk aux state */ 375 struct trim_map *vdev_trimmap; /* map on outstanding trims */ 376 uint64_t vdev_leaf_zap; 377 378 /* 379 * For DTrace to work in userland (libzpool) context, these fields must 380 * remain at the end of the structure. DTrace will use the kernel's 381 * CTF definition for 'struct vdev', and since the size of a kmutex_t is 382 * larger in userland, the offsets for the rest of the fields would be 383 * incorrect. 384 */ 385 kmutex_t vdev_dtl_lock; /* vdev_dtl_{map,resilver} */ 386 kmutex_t vdev_stat_lock; /* vdev_stat */ 387 kmutex_t vdev_probe_lock; /* protects vdev_probe_zio */ 388 }; 389 390 #define VDEV_RAIDZ_MAXPARITY 3 391 392 #define VDEV_PAD_SIZE (8 << 10) 393 /* 2 padding areas (vl_pad1 and vl_pad2) to skip */ 394 #define VDEV_SKIP_SIZE VDEV_PAD_SIZE * 2 395 #define VDEV_PHYS_SIZE (112 << 10) 396 #define VDEV_UBERBLOCK_RING (128 << 10) 397 398 /* The largest uberblock we support is 8k. */ 399 #define MAX_UBERBLOCK_SHIFT (13) 400 #define VDEV_UBERBLOCK_SHIFT(vd) \ 401 MIN(MAX((vd)->vdev_top->vdev_ashift, UBERBLOCK_SHIFT), \ 402 MAX_UBERBLOCK_SHIFT) 403 #define VDEV_UBERBLOCK_COUNT(vd) \ 404 (VDEV_UBERBLOCK_RING >> VDEV_UBERBLOCK_SHIFT(vd)) 405 #define VDEV_UBERBLOCK_OFFSET(vd, n) \ 406 offsetof(vdev_label_t, vl_uberblock[(n) << VDEV_UBERBLOCK_SHIFT(vd)]) 407 #define VDEV_UBERBLOCK_SIZE(vd) (1ULL << VDEV_UBERBLOCK_SHIFT(vd)) 408 409 typedef struct vdev_phys { 410 char vp_nvlist[VDEV_PHYS_SIZE - sizeof (zio_eck_t)]; 411 zio_eck_t vp_zbt; 412 } vdev_phys_t; 413 414 typedef struct vdev_label { 415 char vl_pad1[VDEV_PAD_SIZE]; /* 8K */ 416 char vl_pad2[VDEV_PAD_SIZE]; /* 8K */ 417 vdev_phys_t vl_vdev_phys; /* 112K */ 418 char vl_uberblock[VDEV_UBERBLOCK_RING]; /* 128K */ 419 } vdev_label_t; /* 256K total */ 420 421 /* 422 * vdev_dirty() flags 423 */ 424 #define VDD_METASLAB 0x01 425 #define VDD_DTL 0x02 426 427 /* Offset of embedded boot loader region on each label */ 428 #define VDEV_BOOT_OFFSET (2 * sizeof (vdev_label_t)) 429 /* 430 * Size of embedded boot loader region on each label. 431 * The total size of the first two labels plus the boot area is 4MB. 432 */ 433 #define VDEV_BOOT_SIZE (7ULL << 19) /* 3.5M */ 434 435 /* 436 * Size of label regions at the start and end of each leaf device. 437 */ 438 #define VDEV_LABEL_START_SIZE (2 * sizeof (vdev_label_t) + VDEV_BOOT_SIZE) 439 #define VDEV_LABEL_END_SIZE (2 * sizeof (vdev_label_t)) 440 #define VDEV_LABELS 4 441 #define VDEV_BEST_LABEL VDEV_LABELS 442 443 #define VDEV_ALLOC_LOAD 0 444 #define VDEV_ALLOC_ADD 1 445 #define VDEV_ALLOC_SPARE 2 446 #define VDEV_ALLOC_L2CACHE 3 447 #define VDEV_ALLOC_ROOTPOOL 4 448 #define VDEV_ALLOC_SPLIT 5 449 #define VDEV_ALLOC_ATTACH 6 450 451 /* 452 * Allocate or free a vdev 453 */ 454 extern vdev_t *vdev_alloc_common(spa_t *spa, uint_t id, uint64_t guid, 455 vdev_ops_t *ops); 456 extern int vdev_alloc(spa_t *spa, vdev_t **vdp, nvlist_t *config, 457 vdev_t *parent, uint_t id, int alloctype); 458 extern void vdev_free(vdev_t *vd); 459 460 /* 461 * Add or remove children and parents 462 */ 463 extern void vdev_add_child(vdev_t *pvd, vdev_t *cvd); 464 extern void vdev_remove_child(vdev_t *pvd, vdev_t *cvd); 465 extern void vdev_compact_children(vdev_t *pvd); 466 extern vdev_t *vdev_add_parent(vdev_t *cvd, vdev_ops_t *ops); 467 extern void vdev_remove_parent(vdev_t *cvd); 468 469 /* 470 * vdev sync load and sync 471 */ 472 extern boolean_t vdev_log_state_valid(vdev_t *vd); 473 extern int vdev_load(vdev_t *vd); 474 extern int vdev_dtl_load(vdev_t *vd); 475 extern void vdev_sync(vdev_t *vd, uint64_t txg); 476 extern void vdev_sync_done(vdev_t *vd, uint64_t txg); 477 extern void vdev_dirty(vdev_t *vd, int flags, void *arg, uint64_t txg); 478 extern void vdev_dirty_leaves(vdev_t *vd, int flags, uint64_t txg); 479 480 /* 481 * Available vdev types. 482 */ 483 extern vdev_ops_t vdev_root_ops; 484 extern vdev_ops_t vdev_mirror_ops; 485 extern vdev_ops_t vdev_replacing_ops; 486 extern vdev_ops_t vdev_raidz_ops; 487 #ifdef _KERNEL 488 extern vdev_ops_t vdev_geom_ops; 489 #else 490 extern vdev_ops_t vdev_disk_ops; 491 #endif 492 extern vdev_ops_t vdev_file_ops; 493 extern vdev_ops_t vdev_missing_ops; 494 extern vdev_ops_t vdev_hole_ops; 495 extern vdev_ops_t vdev_spare_ops; 496 extern vdev_ops_t vdev_indirect_ops; 497 498 /* 499 * Common size functions 500 */ 501 extern void vdev_default_xlate(vdev_t *vd, const range_seg_t *in, 502 range_seg_t *out); 503 extern uint64_t vdev_default_asize(vdev_t *vd, uint64_t psize); 504 extern uint64_t vdev_get_min_asize(vdev_t *vd); 505 extern void vdev_set_min_asize(vdev_t *vd); 506 507 /* 508 * Global variables 509 */ 510 extern int vdev_standard_sm_blksz; 511 /* zdb uses this tunable, so it must be declared here to make lint happy. */ 512 extern int zfs_vdev_cache_size; 513 extern uint_t zfs_geom_probe_vdev_key; 514 515 /* 516 * Functions from vdev_indirect.c 517 */ 518 extern void vdev_indirect_sync_obsolete(vdev_t *vd, dmu_tx_t *tx); 519 extern boolean_t vdev_indirect_should_condense(vdev_t *vd); 520 extern void spa_condense_indirect_start_sync(vdev_t *vd, dmu_tx_t *tx); 521 extern int vdev_obsolete_sm_object(vdev_t *vd); 522 extern boolean_t vdev_obsolete_counts_are_precise(vdev_t *vd); 523 524 #ifdef illumos 525 /* 526 * Other miscellaneous functions 527 */ 528 int vdev_checkpoint_sm_object(vdev_t *vd); 529 530 /* 531 * The vdev_buf_t is used to translate between zio_t and buf_t, and back again. 532 */ 533 typedef struct vdev_buf { 534 buf_t vb_buf; /* buffer that describes the io */ 535 zio_t *vb_io; /* pointer back to the original zio_t */ 536 } vdev_buf_t; 537 #endif 538 539 #ifdef __cplusplus 540 } 541 #endif 542 543 #endif /* _SYS_VDEV_IMPL_H */ 544