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      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 <mdb/mdb_ctf.h>
     27 #include <sys/zfs_context.h>
     28 #include <sys/mdb_modapi.h>
     29 #include <sys/dbuf.h>
     30 #include <sys/dmu_objset.h>
     31 #include <sys/dsl_dir.h>
     32 #include <sys/dsl_pool.h>
     33 #include <sys/metaslab_impl.h>
     34 #include <sys/space_map.h>
     35 #include <sys/list.h>
     36 #include <sys/spa_impl.h>
     37 #include <sys/vdev_impl.h>
     38 #include <sys/zap_leaf.h>
     39 #include <sys/zap_impl.h>
     40 #include <ctype.h>
     41 
     42 #ifndef _KERNEL
     43 #include "../genunix/list.h"
     44 #endif
     45 
     46 #ifdef _KERNEL
     47 #define	ZFS_OBJ_NAME	"zfs"
     48 #else
     49 #define	ZFS_OBJ_NAME	"libzpool.so.1"
     50 #endif
     51 
     52 static int
     53 getmember(uintptr_t addr, const char *type, mdb_ctf_id_t *idp,
     54     const char *member, int len, void *buf)
     55 {
     56 	mdb_ctf_id_t id;
     57 	ulong_t off;
     58 	char name[64];
     59 
     60 	if (idp == NULL) {
     61 		if (mdb_ctf_lookup_by_name(type, &id) == -1) {
     62 			mdb_warn("couldn't find type %s", type);
     63 			return (DCMD_ERR);
     64 		}
     65 		idp = &id;
     66 	} else {
     67 		type = name;
     68 		mdb_ctf_type_name(*idp, name, sizeof (name));
     69 	}
     70 
     71 	if (mdb_ctf_offsetof(*idp, member, &off) == -1) {
     72 		mdb_warn("couldn't find member %s of type %s\n", member, type);
     73 		return (DCMD_ERR);
     74 	}
     75 	if (off % 8 != 0) {
     76 		mdb_warn("member %s of type %s is unsupported bitfield",
     77 		    member, type);
     78 		return (DCMD_ERR);
     79 	}
     80 	off /= 8;
     81 
     82 	if (mdb_vread(buf, len, addr + off) == -1) {
     83 		mdb_warn("failed to read %s from %s at %p",
     84 		    member, type, addr + off);
     85 		return (DCMD_ERR);
     86 	}
     87 	/* mdb_warn("read %s from %s at %p+%llx\n", member, type, addr, off); */
     88 
     89 	return (0);
     90 }
     91 
     92 #define	GETMEMB(addr, type, member, dest) \
     93 	getmember(addr, #type, NULL, #member, sizeof (dest), &(dest))
     94 
     95 #define	GETMEMBID(addr, ctfid, member, dest) \
     96 	getmember(addr, NULL, ctfid, #member, sizeof (dest), &(dest))
     97 
     98 static int
     99 getrefcount(uintptr_t addr, mdb_ctf_id_t *id,
    100     const char *member, uint64_t *rc)
    101 {
    102 	static int gotid;
    103 	static mdb_ctf_id_t rc_id;
    104 	ulong_t off;
    105 
    106 	if (!gotid) {
    107 		if (mdb_ctf_lookup_by_name("struct refcount", &rc_id) == -1) {
    108 			mdb_warn("couldn't find struct refcount");
    109 			return (DCMD_ERR);
    110 		}
    111 		gotid = TRUE;
    112 	}
    113 
    114 	if (mdb_ctf_offsetof(*id, member, &off) == -1) {
    115 		char name[64];
    116 		mdb_ctf_type_name(*id, name, sizeof (name));
    117 		mdb_warn("couldn't find member %s of type %s\n", member, name);
    118 		return (DCMD_ERR);
    119 	}
    120 	off /= 8;
    121 
    122 	return (GETMEMBID(addr + off, &rc_id, rc_count, *rc));
    123 }
    124 
    125 static int verbose;
    126 
    127 static int
    128 freelist_walk_init(mdb_walk_state_t *wsp)
    129 {
    130 	if (wsp->walk_addr == NULL) {
    131 		mdb_warn("must supply starting address\n");
    132 		return (WALK_ERR);
    133 	}
    134 
    135 	wsp->walk_data = 0;  /* Index into the freelist */
    136 	return (WALK_NEXT);
    137 }
    138 
    139 static int
    140 freelist_walk_step(mdb_walk_state_t *wsp)
    141 {
    142 	uint64_t entry;
    143 	uintptr_t number = (uintptr_t)wsp->walk_data;
    144 	char *ddata[] = { "ALLOC", "FREE", "CONDENSE", "INVALID",
    145 			    "INVALID", "INVALID", "INVALID", "INVALID" };
    146 	int mapshift = SPA_MINBLOCKSHIFT;
    147 
    148 	if (mdb_vread(&entry, sizeof (entry), wsp->walk_addr) == -1) {
    149 		mdb_warn("failed to read freelist entry %p", wsp->walk_addr);
    150 		return (WALK_DONE);
    151 	}
    152 	wsp->walk_addr += sizeof (entry);
    153 	wsp->walk_data = (void *)(number + 1);
    154 
    155 	if (SM_DEBUG_DECODE(entry)) {
    156 		mdb_printf("DEBUG: %3u  %10s: txg=%llu  pass=%llu\n",
    157 		    number,
    158 		    ddata[SM_DEBUG_ACTION_DECODE(entry)],
    159 		    SM_DEBUG_TXG_DECODE(entry),
    160 		    SM_DEBUG_SYNCPASS_DECODE(entry));
    161 	} else {
    162 		mdb_printf("Entry: %3u  offsets=%08llx-%08llx  type=%c  "
    163 		    "size=%06llx", number,
    164 		    SM_OFFSET_DECODE(entry) << mapshift,
    165 		    (SM_OFFSET_DECODE(entry) + SM_RUN_DECODE(entry)) <<
    166 		    mapshift,
    167 		    SM_TYPE_DECODE(entry) == SM_ALLOC ? 'A' : 'F',
    168 		    SM_RUN_DECODE(entry) << mapshift);
    169 		if (verbose)
    170 			mdb_printf("      (raw=%012llx)\n", entry);
    171 		mdb_printf("\n");
    172 	}
    173 	return (WALK_NEXT);
    174 }
    175 
    176 
    177 static int
    178 dataset_name(uintptr_t addr, char *buf)
    179 {
    180 	static int gotid;
    181 	static mdb_ctf_id_t dd_id;
    182 	uintptr_t dd_parent;
    183 	char dd_myname[MAXNAMELEN];
    184 
    185 	if (!gotid) {
    186 		if (mdb_ctf_lookup_by_name("struct dsl_dir",
    187 		    &dd_id) == -1) {
    188 			mdb_warn("couldn't find struct dsl_dir");
    189 			return (DCMD_ERR);
    190 		}
    191 		gotid = TRUE;
    192 	}
    193 	if (GETMEMBID(addr, &dd_id, dd_parent, dd_parent) ||
    194 	    GETMEMBID(addr, &dd_id, dd_myname, dd_myname)) {
    195 		return (DCMD_ERR);
    196 	}
    197 
    198 	if (dd_parent) {
    199 		if (dataset_name(dd_parent, buf))
    200 			return (DCMD_ERR);
    201 		strcat(buf, "/");
    202 	}
    203 
    204 	if (dd_myname[0])
    205 		strcat(buf, dd_myname);
    206 	else
    207 		strcat(buf, "???");
    208 
    209 	return (0);
    210 }
    211 
    212 static int
    213 objset_name(uintptr_t addr, char *buf)
    214 {
    215 	static int gotid;
    216 	static mdb_ctf_id_t os_id, ds_id;
    217 	uintptr_t os_dsl_dataset;
    218 	char ds_snapname[MAXNAMELEN];
    219 	uintptr_t ds_dir;
    220 
    221 	buf[0] = '\0';
    222 
    223 	if (!gotid) {
    224 		if (mdb_ctf_lookup_by_name("struct objset",
    225 		    &os_id) == -1) {
    226 			mdb_warn("couldn't find struct objset");
    227 			return (DCMD_ERR);
    228 		}
    229 		if (mdb_ctf_lookup_by_name("struct dsl_dataset",
    230 		    &ds_id) == -1) {
    231 			mdb_warn("couldn't find struct dsl_dataset");
    232 			return (DCMD_ERR);
    233 		}
    234 
    235 		gotid = TRUE;
    236 	}
    237 
    238 	if (GETMEMBID(addr, &os_id, os_dsl_dataset, os_dsl_dataset))
    239 		return (DCMD_ERR);
    240 
    241 	if (os_dsl_dataset == 0) {
    242 		strcat(buf, "mos");
    243 		return (0);
    244 	}
    245 
    246 	if (GETMEMBID(os_dsl_dataset, &ds_id, ds_snapname, ds_snapname) ||
    247 	    GETMEMBID(os_dsl_dataset, &ds_id, ds_dir, ds_dir)) {
    248 		return (DCMD_ERR);
    249 	}
    250 
    251 	if (ds_dir && dataset_name(ds_dir, buf))
    252 		return (DCMD_ERR);
    253 
    254 	if (ds_snapname[0]) {
    255 		strcat(buf, "@");
    256 		strcat(buf, ds_snapname);
    257 	}
    258 	return (0);
    259 }
    260 
    261 static void
    262 enum_lookup(char *out, size_t size, mdb_ctf_id_t id, int val,
    263     const char *prefix)
    264 {
    265 	const char *cp;
    266 	size_t len = strlen(prefix);
    267 
    268 	if ((cp = mdb_ctf_enum_name(id, val)) != NULL) {
    269 		if (strncmp(cp, prefix, len) == 0)
    270 			cp += len;
    271 		(void) strncpy(out, cp, size);
    272 	} else {
    273 		mdb_snprintf(out, size, "? (%d)", val);
    274 	}
    275 }
    276 
    277 /* ARGSUSED */
    278 static int
    279 zfs_params(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
    280 {
    281 	/*
    282 	 * This table can be approximately generated by running:
    283 	 * egrep "^[a-z0-9_]+ [a-z0-9_]+( =.*)?;" *.c | cut -d ' ' -f 2
    284 	 */
    285 	static const char *params[] = {
    286 		"arc_reduce_dnlc_percent",
    287 		"zfs_arc_max",
    288 		"zfs_arc_min",
    289 		"arc_shrink_shift",
    290 		"zfs_mdcomp_disable",
    291 		"zfs_prefetch_disable",
    292 		"zfetch_max_streams",
    293 		"zfetch_min_sec_reap",
    294 		"zfetch_block_cap",
    295 		"zfetch_array_rd_sz",
    296 		"zfs_default_bs",
    297 		"zfs_default_ibs",
    298 		"metaslab_aliquot",
    299 		"reference_tracking_enable",
    300 		"reference_history",
    301 		"spa_max_replication_override",
    302 		"spa_mode_global",
    303 		"zfs_flags",
    304 		"zfs_txg_synctime",
    305 		"zfs_txg_timeout",
    306 		"zfs_write_limit_min",
    307 		"zfs_write_limit_max",
    308 		"zfs_write_limit_shift",
    309 		"zfs_write_limit_override",
    310 		"zfs_no_write_throttle",
    311 		"zfs_vdev_cache_max",
    312 		"zfs_vdev_cache_size",
    313 		"zfs_vdev_cache_bshift",
    314 		"vdev_mirror_shift",
    315 		"zfs_vdev_max_pending",
    316 		"zfs_vdev_min_pending",
    317 		"zfs_scrub_limit",
    318 		"zfs_no_scrub_io",
    319 		"zfs_no_scrub_prefetch",
    320 		"zfs_vdev_time_shift",
    321 		"zfs_vdev_ramp_rate",
    322 		"zfs_vdev_aggregation_limit",
    323 		"fzap_default_block_shift",
    324 		"zfs_immediate_write_sz",
    325 		"zfs_read_chunk_size",
    326 		"zil_disable",
    327 		"zfs_nocacheflush",
    328 		"metaslab_gang_bang",
    329 		"metaslab_df_alloc_threshold",
    330 		"metaslab_df_free_pct",
    331 		"zio_injection_enabled",
    332 		"zvol_immediate_write_sz",
    333 	};
    334 
    335 	for (int i = 0; i < sizeof (params) / sizeof (params[0]); i++) {
    336 		int sz;
    337 		uint64_t val64;
    338 		uint32_t *val32p = (uint32_t *)&val64;
    339 
    340 		sz = mdb_readvar(&val64, params[i]);
    341 		if (sz == 4) {
    342 			mdb_printf("%s = 0x%x\n", params[i], *val32p);
    343 		} else if (sz == 8) {
    344 			mdb_printf("%s = 0x%llx\n", params[i], val64);
    345 		} else {
    346 			mdb_warn("variable %s not found", params[i]);
    347 		}
    348 	}
    349 
    350 	return (DCMD_OK);
    351 }
    352 
    353 /* ARGSUSED */
    354 static int
    355 blkptr(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
    356 {
    357 	mdb_ctf_id_t type_enum, checksum_enum, compress_enum;
    358 	char type[80], checksum[80], compress[80];
    359 	blkptr_t blk, *bp = &blk;
    360 	char buf[BP_SPRINTF_LEN];
    361 
    362 	if (mdb_vread(&blk, sizeof (blkptr_t), addr) == -1) {
    363 		mdb_warn("failed to read blkptr_t");
    364 		return (DCMD_ERR);
    365 	}
    366 
    367 	if (mdb_ctf_lookup_by_name("enum dmu_object_type", &type_enum) == -1 ||
    368 	    mdb_ctf_lookup_by_name("enum zio_checksum", &checksum_enum) == -1 ||
    369 	    mdb_ctf_lookup_by_name("enum zio_compress", &compress_enum) == -1) {
    370 		mdb_warn("Could not find blkptr enumerated types");
    371 		return (DCMD_ERR);
    372 	}
    373 
    374 	enum_lookup(type, sizeof (type), type_enum,
    375 	    BP_GET_TYPE(bp), "DMU_OT_");
    376 	enum_lookup(checksum, sizeof (checksum), checksum_enum,
    377 	    BP_GET_CHECKSUM(bp), "ZIO_CHECKSUM_");
    378 	enum_lookup(compress, sizeof (compress), compress_enum,
    379 	    BP_GET_COMPRESS(bp), "ZIO_COMPRESS_");
    380 
    381 	SPRINTF_BLKPTR(mdb_snprintf, '\n', buf, bp, type, checksum, compress);
    382 
    383 	mdb_printf("%s\n", buf);
    384 
    385 	return (DCMD_OK);
    386 }
    387 
    388 /* ARGSUSED */
    389 static int
    390 dbuf(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
    391 {
    392 	mdb_ctf_id_t id;
    393 	dmu_buf_t db;
    394 	uintptr_t objset;
    395 	uint8_t level;
    396 	uint64_t blkid;
    397 	uint64_t holds;
    398 	char objectname[32];
    399 	char blkidname[32];
    400 	char path[MAXNAMELEN];
    401 
    402 	if (DCMD_HDRSPEC(flags)) {
    403 		mdb_printf("        addr object lvl blkid holds os\n");
    404 	}
    405 
    406 	if (mdb_ctf_lookup_by_name("struct dmu_buf_impl", &id) == -1) {
    407 		mdb_warn("couldn't find struct dmu_buf_impl_t");
    408 		return (DCMD_ERR);
    409 	}
    410 
    411 	if (GETMEMBID(addr, &id, db_objset, objset) ||
    412 	    GETMEMBID(addr, &id, db, db) ||
    413 	    GETMEMBID(addr, &id, db_level, level) ||
    414 	    GETMEMBID(addr, &id, db_blkid, blkid)) {
    415 		return (WALK_ERR);
    416 	}
    417 
    418 	if (getrefcount(addr, &id, "db_holds", &holds)) {
    419 		return (WALK_ERR);
    420 	}
    421 
    422 	if (db.db_object == DMU_META_DNODE_OBJECT)
    423 		(void) strcpy(objectname, "mdn");
    424 	else
    425 		(void) mdb_snprintf(objectname, sizeof (objectname), "%llx",
    426 		    (u_longlong_t)db.db_object);
    427 
    428 	if (blkid == DB_BONUS_BLKID)
    429 		(void) strcpy(blkidname, "bonus");
    430 	else
    431 		(void) mdb_snprintf(blkidname, sizeof (blkidname), "%llx",
    432 		    (u_longlong_t)blkid);
    433 
    434 	if (objset_name(objset, path)) {
    435 		return (WALK_ERR);
    436 	}
    437 
    438 	mdb_printf("%p %8s %1u %9s %2llu %s\n",
    439 	    addr, objectname, level, blkidname, holds, path);
    440 
    441 	return (DCMD_OK);
    442 }
    443 
    444 /* ARGSUSED */
    445 static int
    446 dbuf_stats(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
    447 {
    448 #define	HISTOSZ 32
    449 	uintptr_t dbp;
    450 	dmu_buf_impl_t db;
    451 	dbuf_hash_table_t ht;
    452 	uint64_t bucket, ndbufs;
    453 	uint64_t histo[HISTOSZ];
    454 	uint64_t histo2[HISTOSZ];
    455 	int i, maxidx;
    456 
    457 	if (mdb_readvar(&ht, "dbuf_hash_table") == -1) {
    458 		mdb_warn("failed to read 'dbuf_hash_table'");
    459 		return (DCMD_ERR);
    460 	}
    461 
    462 	for (i = 0; i < HISTOSZ; i++) {
    463 		histo[i] = 0;
    464 		histo2[i] = 0;
    465 	}
    466 
    467 	ndbufs = 0;
    468 	for (bucket = 0; bucket < ht.hash_table_mask+1; bucket++) {
    469 		int len;
    470 
    471 		if (mdb_vread(&dbp, sizeof (void *),
    472 		    (uintptr_t)(ht.hash_table+bucket)) == -1) {
    473 			mdb_warn("failed to read hash bucket %u at %p",
    474 			    bucket, ht.hash_table+bucket);
    475 			return (DCMD_ERR);
    476 		}
    477 
    478 		len = 0;
    479 		while (dbp != 0) {
    480 			if (mdb_vread(&db, sizeof (dmu_buf_impl_t),
    481 			    dbp) == -1) {
    482 				mdb_warn("failed to read dbuf at %p", dbp);
    483 				return (DCMD_ERR);
    484 			}
    485 			dbp = (uintptr_t)db.db_hash_next;
    486 			for (i = MIN(len, HISTOSZ - 1); i >= 0; i--)
    487 				histo2[i]++;
    488 			len++;
    489 			ndbufs++;
    490 		}
    491 
    492 		if (len >= HISTOSZ)
    493 			len = HISTOSZ-1;
    494 		histo[len]++;
    495 	}
    496 
    497 	mdb_printf("hash table has %llu buckets, %llu dbufs "
    498 	    "(avg %llu buckets/dbuf)\n",
    499 	    ht.hash_table_mask+1, ndbufs,
    500 	    (ht.hash_table_mask+1)/ndbufs);
    501 
    502 	mdb_printf("\n");
    503 	maxidx = 0;
    504 	for (i = 0; i < HISTOSZ; i++)
    505 		if (histo[i] > 0)
    506 			maxidx = i;
    507 	mdb_printf("hash chain length	number of buckets\n");
    508 	for (i = 0; i <= maxidx; i++)
    509 		mdb_printf("%u			%llu\n", i, histo[i]);
    510 
    511 	mdb_printf("\n");
    512 	maxidx = 0;
    513 	for (i = 0; i < HISTOSZ; i++)
    514 		if (histo2[i] > 0)
    515 			maxidx = i;
    516 	mdb_printf("hash chain depth	number of dbufs\n");
    517 	for (i = 0; i <= maxidx; i++)
    518 		mdb_printf("%u or more		%llu	%llu%%\n",
    519 		    i, histo2[i], histo2[i]*100/ndbufs);
    520 
    521 
    522 	return (DCMD_OK);
    523 }
    524 
    525 #define	CHAIN_END 0xffff
    526 /*
    527  * ::zap_leaf [-v]
    528  *
    529  * Print a zap_leaf_phys_t, assumed to be 16k
    530  */
    531 /* ARGSUSED */
    532 static int
    533 zap_leaf(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
    534 {
    535 	char buf[16*1024];
    536 	int verbose = B_FALSE;
    537 	int four = B_FALSE;
    538 	zap_leaf_t l;
    539 	zap_leaf_phys_t *zlp = (void *)buf;
    540 	int i;
    541 
    542 	if (mdb_getopts(argc, argv,
    543 	    'v', MDB_OPT_SETBITS, TRUE, &verbose,
    544 	    '4', MDB_OPT_SETBITS, TRUE, &four,
    545 	    NULL) != argc)
    546 		return (DCMD_USAGE);
    547 
    548 	l.l_phys = zlp;
    549 	l.l_bs = 14; /* assume 16k blocks */
    550 	if (four)
    551 		l.l_bs = 12;
    552 
    553 	if (!(flags & DCMD_ADDRSPEC)) {
    554 		return (DCMD_USAGE);
    555 	}
    556 
    557 	if (mdb_vread(buf, sizeof (buf), addr) == -1) {
    558 		mdb_warn("failed to read zap_leaf_phys_t at %p", addr);
    559 		return (DCMD_ERR);
    560 	}
    561 
    562 	if (zlp->l_hdr.lh_block_type != ZBT_LEAF ||
    563 	    zlp->l_hdr.lh_magic != ZAP_LEAF_MAGIC) {
    564 		mdb_warn("This does not appear to be a zap_leaf_phys_t");
    565 		return (DCMD_ERR);
    566 	}
    567 
    568 	mdb_printf("zap_leaf_phys_t at %p:\n", addr);
    569 	mdb_printf("    lh_prefix_len = %u\n", zlp->l_hdr.lh_prefix_len);
    570 	mdb_printf("    lh_prefix = %llx\n", zlp->l_hdr.lh_prefix);
    571 	mdb_printf("    lh_nentries = %u\n", zlp->l_hdr.lh_nentries);
    572 	mdb_printf("    lh_nfree = %u\n", zlp->l_hdr.lh_nfree,
    573 	    zlp->l_hdr.lh_nfree * 100 / (ZAP_LEAF_NUMCHUNKS(&l)));
    574 	mdb_printf("    lh_freelist = %u\n", zlp->l_hdr.lh_freelist);
    575 	mdb_printf("    lh_flags = %x (%s)\n", zlp->l_hdr.lh_flags,
    576 	    zlp->l_hdr.lh_flags & ZLF_ENTRIES_CDSORTED ?
    577 	    "ENTRIES_CDSORTED" : "");
    578 
    579 	if (verbose) {
    580 		mdb_printf(" hash table:\n");
    581 		for (i = 0; i < ZAP_LEAF_HASH_NUMENTRIES(&l); i++) {
    582 			if (zlp->l_hash[i] != CHAIN_END)
    583 				mdb_printf("    %u: %u\n", i, zlp->l_hash[i]);
    584 		}
    585 	}
    586 
    587 	mdb_printf(" chunks:\n");
    588 	for (i = 0; i < ZAP_LEAF_NUMCHUNKS(&l); i++) {
    589 		/* LINTED: alignment */
    590 		zap_leaf_chunk_t *zlc = &ZAP_LEAF_CHUNK(&l, i);
    591 		switch (zlc->l_entry.le_type) {
    592 		case ZAP_CHUNK_FREE:
    593 			if (verbose) {
    594 				mdb_printf("    %u: free; lf_next = %u\n",
    595 				    i, zlc->l_free.lf_next);
    596 			}
    597 			break;
    598 		case ZAP_CHUNK_ENTRY:
    599 			mdb_printf("    %u: entry\n", i);
    600 			if (verbose) {
    601 				mdb_printf("        le_next = %u\n",
    602 				    zlc->l_entry.le_next);
    603 			}
    604 			mdb_printf("        le_name_chunk = %u\n",
    605 			    zlc->l_entry.le_name_chunk);
    606 			mdb_printf("        le_name_numints = %u\n",
    607 			    zlc->l_entry.le_name_numints);
    608 			mdb_printf("        le_value_chunk = %u\n",
    609 			    zlc->l_entry.le_value_chunk);
    610 			mdb_printf("        le_value_intlen = %u\n",
    611 			    zlc->l_entry.le_value_intlen);
    612 			mdb_printf("        le_value_numints = %u\n",
    613 			    zlc->l_entry.le_value_numints);
    614 			mdb_printf("        le_cd = %u\n",
    615 			    zlc->l_entry.le_cd);
    616 			mdb_printf("        le_hash = %llx\n",
    617 			    zlc->l_entry.le_hash);
    618 			break;
    619 		case ZAP_CHUNK_ARRAY:
    620 			mdb_printf("    %u: array \"%s\"\n",
    621 			    i, zlc->l_array.la_array);
    622 			if (verbose) {
    623 				int j;
    624 				mdb_printf("        ");
    625 				for (j = 0; j < ZAP_LEAF_ARRAY_BYTES; j++) {
    626 					mdb_printf("%02x ",
    627 					    zlc->l_array.la_array[j]);
    628 				}
    629 				mdb_printf("\n");
    630 			}
    631 			if (zlc->l_array.la_next != CHAIN_END) {
    632 				mdb_printf("        lf_next = %u\n",
    633 				    zlc->l_array.la_next);
    634 			}
    635 			break;
    636 		default:
    637 			mdb_printf("    %u: undefined type %u\n",
    638 			    zlc->l_entry.le_type);
    639 		}
    640 	}
    641 
    642 	return (DCMD_OK);
    643 }
    644 
    645 typedef struct dbufs_data {
    646 	mdb_ctf_id_t id;
    647 	uint64_t objset;
    648 	uint64_t object;
    649 	uint64_t level;
    650 	uint64_t blkid;
    651 	char *osname;
    652 } dbufs_data_t;
    653 
    654 #define	DBUFS_UNSET	(0xbaddcafedeadbeefULL)
    655 
    656 /* ARGSUSED */
    657 static int
    658 dbufs_cb(uintptr_t addr, const void *unknown, void *arg)
    659 {
    660 	dbufs_data_t *data = arg;
    661 	uintptr_t objset;
    662 	dmu_buf_t db;
    663 	uint8_t level;
    664 	uint64_t blkid;
    665 	char osname[MAXNAMELEN];
    666 
    667 	if (GETMEMBID(addr, &data->id, db_objset, objset) ||
    668 	    GETMEMBID(addr, &data->id, db, db) ||
    669 	    GETMEMBID(addr, &data->id, db_level, level) ||
    670 	    GETMEMBID(addr, &data->id, db_blkid, blkid)) {
    671 		return (WALK_ERR);
    672 	}
    673 
    674 	if ((data->objset == DBUFS_UNSET || data->objset == objset) &&
    675 	    (data->osname == NULL || (objset_name(objset, osname) == 0 &&
    676 	    strcmp(data->osname, osname) == 0)) &&
    677 	    (data->object == DBUFS_UNSET || data->object == db.db_object) &&
    678 	    (data->level == DBUFS_UNSET || data->level == level) &&
    679 	    (data->blkid == DBUFS_UNSET || data->blkid == blkid)) {
    680 		mdb_printf("%#lr\n", addr);
    681 	}
    682 	return (WALK_NEXT);
    683 }
    684 
    685 /* ARGSUSED */
    686 static int
    687 dbufs(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
    688 {
    689 	dbufs_data_t data;
    690 	char *object = NULL;
    691 	char *blkid = NULL;
    692 
    693 	data.objset = data.object = data.level = data.blkid = DBUFS_UNSET;
    694 	data.osname = NULL;
    695 
    696 	if (mdb_getopts(argc, argv,
    697 	    'O', MDB_OPT_UINT64, &data.objset,
    698 	    'n', MDB_OPT_STR, &data.osname,
    699 	    'o', MDB_OPT_STR, &object,
    700 	    'l', MDB_OPT_UINT64, &data.level,
    701 	    'b', MDB_OPT_STR, &blkid) != argc) {
    702 		return (DCMD_USAGE);
    703 	}
    704 
    705 	if (object) {
    706 		if (strcmp(object, "mdn") == 0) {
    707 			data.object = DMU_META_DNODE_OBJECT;
    708 		} else {
    709 			data.object = mdb_strtoull(object);
    710 		}
    711 	}
    712 
    713 	if (blkid) {
    714 		if (strcmp(blkid, "bonus") == 0) {
    715 			data.blkid = DB_BONUS_BLKID;
    716 		} else {
    717 			data.blkid = mdb_strtoull(blkid);
    718 		}
    719 	}
    720 
    721 	if (mdb_ctf_lookup_by_name("struct dmu_buf_impl", &data.id) == -1) {
    722 		mdb_warn("couldn't find struct dmu_buf_impl_t");
    723 		return (DCMD_ERR);
    724 	}
    725 
    726 	if (mdb_walk("dmu_buf_impl_t", dbufs_cb, &data) != 0) {
    727 		mdb_warn("can't walk dbufs");
    728 		return (DCMD_ERR);
    729 	}
    730 
    731 	return (DCMD_OK);
    732 }
    733 
    734 typedef struct abuf_find_data {
    735 	dva_t dva;
    736 	mdb_ctf_id_t id;
    737 } abuf_find_data_t;
    738 
    739 /* ARGSUSED */
    740 static int
    741 abuf_find_cb(uintptr_t addr, const void *unknown, void *arg)
    742 {
    743 	abuf_find_data_t *data = arg;
    744 	dva_t dva;
    745 
    746 	if (GETMEMBID(addr, &data->id, b_dva, dva)) {
    747 		return (WALK_ERR);
    748 	}
    749 
    750 	if (dva.dva_word[0] == data->dva.dva_word[0] &&
    751 	    dva.dva_word[1] == data->dva.dva_word[1]) {
    752 		mdb_printf("%#lr\n", addr);
    753 	}
    754 	return (WALK_NEXT);
    755 }
    756 
    757 /* ARGSUSED */
    758 static int
    759 abuf_find(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
    760 {
    761 	abuf_find_data_t data;
    762 	GElf_Sym sym;
    763 	int i;
    764 	const char *syms[] = {
    765 		"ARC_mru",
    766 		"ARC_mru_ghost",
    767 		"ARC_mfu",
    768 		"ARC_mfu_ghost",
    769 	};
    770 
    771 	if (argc != 2)
    772 		return (DCMD_USAGE);
    773 
    774 	for (i = 0; i < 2; i ++) {
    775 		switch (argv[i].a_type) {
    776 		case MDB_TYPE_STRING:
    777 			data.dva.dva_word[i] = mdb_strtoull(argv[i].a_un.a_str);
    778 			break;
    779 		case MDB_TYPE_IMMEDIATE:
    780 			data.dva.dva_word[i] = argv[i].a_un.a_val;
    781 			break;
    782 		default:
    783 			return (DCMD_USAGE);
    784 		}
    785 	}
    786 
    787 	if (mdb_ctf_lookup_by_name("struct arc_buf_hdr", &data.id) == -1) {
    788 		mdb_warn("couldn't find struct arc_buf_hdr");
    789 		return (DCMD_ERR);
    790 	}
    791 
    792 	for (i = 0; i < sizeof (syms) / sizeof (syms[0]); i++) {
    793 		if (mdb_lookup_by_name(syms[i], &sym)) {
    794 			mdb_warn("can't find symbol %s", syms[i]);
    795 			return (DCMD_ERR);
    796 		}
    797 
    798 		if (mdb_pwalk("list", abuf_find_cb, &data, sym.st_value) != 0) {
    799 			mdb_warn("can't walk %s", syms[i]);
    800 			return (DCMD_ERR);
    801 		}
    802 	}
    803 
    804 	return (DCMD_OK);
    805 }
    806 
    807 /*ARGSUSED*/
    808 static int
    809 arc_print(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
    810 {
    811 	kstat_named_t *stats;
    812 	GElf_Sym sym;
    813 	int nstats, i;
    814 	uint_t opt_a = FALSE;
    815 	uint_t opt_b = FALSE;
    816 	uint_t shift = 0;
    817 	const char *suffix;
    818 
    819 	static const char *bytestats[] = {
    820 		"p", "c", "c_min", "c_max", "size", NULL
    821 	};
    822 
    823 	static const char *extras[] = {
    824 		"arc_no_grow", "arc_tempreserve",
    825 		"arc_meta_used", "arc_meta_limit", "arc_meta_max",
    826 		NULL
    827 	};
    828 
    829 	if (mdb_lookup_by_name("arc_stats", &sym) == -1) {
    830 		mdb_warn("failed to find 'arc_stats'");
    831 		return (DCMD_ERR);
    832 	}
    833 
    834 	stats = mdb_zalloc(sym.st_size, UM_SLEEP | UM_GC);
    835 
    836 	if (mdb_vread(stats, sym.st_size, sym.st_value) == -1) {
    837 		mdb_warn("couldn't read 'arc_stats' at %p", sym.st_value);
    838 		return (DCMD_ERR);
    839 	}
    840 
    841 	nstats = sym.st_size / sizeof (kstat_named_t);
    842 
    843 	/* NB: -a / opt_a are ignored for backwards compatability */
    844 	if (mdb_getopts(argc, argv,
    845 	    'a', MDB_OPT_SETBITS, TRUE, &opt_a,
    846 	    'b', MDB_OPT_SETBITS, TRUE, &opt_b,
    847 	    'k', MDB_OPT_SETBITS, 10, &shift,
    848 	    'm', MDB_OPT_SETBITS, 20, &shift,
    849 	    'g', MDB_OPT_SETBITS, 30, &shift,
    850 	    NULL) != argc)
    851 		return (DCMD_USAGE);
    852 
    853 	if (!opt_b && !shift)
    854 		shift = 20;
    855 
    856 	switch (shift) {
    857 	case 0:
    858 		suffix = "B";
    859 		break;
    860 	case 10:
    861 		suffix = "KB";
    862 		break;
    863 	case 20:
    864 		suffix = "MB";
    865 		break;
    866 	case 30:
    867 		suffix = "GB";
    868 		break;
    869 	default:
    870 		suffix = "XX";
    871 	}
    872 
    873 	for (i = 0; i < nstats; i++) {
    874 		int j;
    875 		boolean_t bytes = B_FALSE;
    876 
    877 		for (j = 0; bytestats[j]; j++) {
    878 			if (strcmp(stats[i].name, bytestats[j]) == 0) {
    879 				bytes = B_TRUE;
    880 				break;
    881 			}
    882 		}
    883 
    884 		if (bytes) {
    885 			mdb_printf("%-25s = %9llu %s\n", stats[i].name,
    886 			    stats[i].value.ui64 >> shift, suffix);
    887 		} else {
    888 			mdb_printf("%-25s = %9llu\n", stats[i].name,
    889 			    stats[i].value.ui64);
    890 		}
    891 	}
    892 
    893 	for (i = 0; extras[i]; i++) {
    894 		uint64_t buf;
    895 
    896 		if (mdb_lookup_by_name(extras[i], &sym) == -1) {
    897 			mdb_warn("failed to find '%s'", extras[i]);
    898 			return (DCMD_ERR);
    899 		}
    900 
    901 		if (sym.st_size != sizeof (uint64_t) &&
    902 		    sym.st_size != sizeof (uint32_t)) {
    903 			mdb_warn("expected scalar for variable '%s'\n",
    904 			    extras[i]);
    905 			return (DCMD_ERR);
    906 		}
    907 
    908 		if (mdb_vread(&buf, sym.st_size, sym.st_value) == -1) {
    909 			mdb_warn("couldn't read '%s'", extras[i]);
    910 			return (DCMD_ERR);
    911 		}
    912 
    913 		mdb_printf("%-25s = ", extras[i]);
    914 
    915 		/* NB: all the 64-bit extras happen to be byte counts */
    916 		if (sym.st_size == sizeof (uint64_t))
    917 			mdb_printf("%9llu %s\n", buf >> shift, suffix);
    918 
    919 		if (sym.st_size == sizeof (uint32_t))
    920 			mdb_printf("%9d\n", *((uint32_t *)&buf));
    921 	}
    922 	return (DCMD_OK);
    923 }
    924 
    925 /*
    926  * ::spa
    927  *
    928  * 	-c	Print configuration information as well
    929  * 	-v	Print vdev state
    930  * 	-e	Print vdev error stats
    931  *
    932  * Print a summarized spa_t.  When given no arguments, prints out a table of all
    933  * active pools on the system.
    934  */
    935 /* ARGSUSED */
    936 static int
    937 spa_print(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
    938 {
    939 	spa_t spa;
    940 	const char *statetab[] = { "ACTIVE", "EXPORTED", "DESTROYED",
    941 		"SPARE", "L2CACHE", "UNINIT", "UNAVAIL", "POTENTIAL" };
    942 	const char *state;
    943 	int config = FALSE;
    944 	int vdevs = FALSE;
    945 	int errors = FALSE;
    946 
    947 	if (mdb_getopts(argc, argv,
    948 	    'c', MDB_OPT_SETBITS, TRUE, &config,
    949 	    'v', MDB_OPT_SETBITS, TRUE, &vdevs,
    950 	    'e', MDB_OPT_SETBITS, TRUE, &errors,
    951 	    NULL) != argc)
    952 		return (DCMD_USAGE);
    953 
    954 	if (!(flags & DCMD_ADDRSPEC)) {
    955 		if (mdb_walk_dcmd("spa", "spa", argc, argv) == -1) {
    956 			mdb_warn("can't walk spa");
    957 			return (DCMD_ERR);
    958 		}
    959 
    960 		return (DCMD_OK);
    961 	}
    962 
    963 	if (flags & DCMD_PIPE_OUT) {
    964 		mdb_printf("%#lr\n", addr);
    965 		return (DCMD_OK);
    966 	}
    967 
    968 	if (DCMD_HDRSPEC(flags))
    969 		mdb_printf("%<u>%-?s %9s %-*s%</u>\n", "ADDR", "STATE",
    970 		    sizeof (uintptr_t) == 4 ? 60 : 52, "NAME");
    971 
    972 	if (mdb_vread(&spa, sizeof (spa), addr) == -1) {
    973 		mdb_warn("failed to read spa_t at %p", addr);
    974 		return (DCMD_ERR);
    975 	}
    976 
    977 	if (spa.spa_state < 0 || spa.spa_state > POOL_STATE_UNAVAIL)
    978 		state = "UNKNOWN";
    979 	else
    980 		state = statetab[spa.spa_state];
    981 
    982 	mdb_printf("%0?p %9s %s\n", addr, state, spa.spa_name);
    983 
    984 	if (config) {
    985 		mdb_printf("\n");
    986 		mdb_inc_indent(4);
    987 		if (mdb_call_dcmd("spa_config", addr, flags, 0,
    988 		    NULL) != DCMD_OK)
    989 			return (DCMD_ERR);
    990 		mdb_dec_indent(4);
    991 	}
    992 
    993 	if (vdevs || errors) {
    994 		mdb_arg_t v;
    995 
    996 		v.a_type = MDB_TYPE_STRING;
    997 		v.a_un.a_str = "-e";
    998 
    999 		mdb_printf("\n");
   1000 		mdb_inc_indent(4);
   1001 		if (mdb_call_dcmd("spa_vdevs", addr, flags, errors ? 1 : 0,
   1002 		    &v) != DCMD_OK)
   1003 			return (DCMD_ERR);
   1004 		mdb_dec_indent(4);
   1005 	}
   1006 
   1007 	return (DCMD_OK);
   1008 }
   1009 
   1010 /*
   1011  * ::spa_config
   1012  *
   1013  * Given a spa_t, print the configuration information stored in spa_config.
   1014  * Since it's just an nvlist, format it as an indented list of name=value pairs.
   1015  * We simply read the value of spa_config and pass off to ::nvlist.
   1016  */
   1017 /* ARGSUSED */
   1018 static int
   1019 spa_print_config(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
   1020 {
   1021 	spa_t spa;
   1022 
   1023 	if (argc != 0 || !(flags & DCMD_ADDRSPEC))
   1024 		return (DCMD_USAGE);
   1025 
   1026 	if (mdb_vread(&spa, sizeof (spa), addr) == -1) {
   1027 		mdb_warn("failed to read spa_t at %p", addr);
   1028 		return (DCMD_ERR);
   1029 	}
   1030 
   1031 	if (spa.spa_config == NULL) {
   1032 		mdb_printf("(none)\n");
   1033 		return (DCMD_OK);
   1034 	}
   1035 
   1036 	return (mdb_call_dcmd("nvlist", (uintptr_t)spa.spa_config, flags,
   1037 	    0, NULL));
   1038 }
   1039 
   1040 /*
   1041  * ::vdev
   1042  *
   1043  * Print out a summarized vdev_t, in the following form:
   1044  *
   1045  * ADDR             STATE	AUX            DESC
   1046  * fffffffbcde23df0 HEALTHY	-              /dev/dsk/c0t0d0
   1047  *
   1048  * If '-r' is specified, recursively visit all children.
   1049  *
   1050  * With '-e', the statistics associated with the vdev are printed as well.
   1051  */
   1052 static int
   1053 do_print_vdev(uintptr_t addr, int flags, int depth, int stats,
   1054     int recursive)
   1055 {
   1056 	vdev_t vdev;
   1057 	char desc[MAXNAMELEN];
   1058 	int c, children;
   1059 	uintptr_t *child;
   1060 	const char *state, *aux;
   1061 
   1062 	if (mdb_vread(&vdev, sizeof (vdev), (uintptr_t)addr) == -1) {
   1063 		mdb_warn("failed to read vdev_t at %p\n", (uintptr_t)addr);
   1064 		return (DCMD_ERR);
   1065 	}
   1066 
   1067 	if (flags & DCMD_PIPE_OUT) {
   1068 		mdb_printf("%#lr", addr);
   1069 	} else {
   1070 		if (vdev.vdev_path != NULL) {
   1071 			if (mdb_readstr(desc, sizeof (desc),
   1072 			    (uintptr_t)vdev.vdev_path) == -1) {
   1073 				mdb_warn("failed to read vdev_path at %p\n",
   1074 				    vdev.vdev_path);
   1075 				return (DCMD_ERR);
   1076 			}
   1077 		} else if (vdev.vdev_ops != NULL) {
   1078 			vdev_ops_t ops;
   1079 			if (mdb_vread(&ops, sizeof (ops),
   1080 			    (uintptr_t)vdev.vdev_ops) == -1) {
   1081 				mdb_warn("failed to read vdev_ops at %p\n",
   1082 				    vdev.vdev_ops);
   1083 				return (DCMD_ERR);
   1084 			}
   1085 			(void) strcpy(desc, ops.vdev_op_type);
   1086 		} else {
   1087 			(void) strcpy(desc, "<unknown>");
   1088 		}
   1089 
   1090 		if (depth == 0 && DCMD_HDRSPEC(flags))
   1091 			mdb_printf("%<u>%-?s %-9s %-12s %-*s%</u>\n",
   1092 			    "ADDR", "STATE", "AUX",
   1093 			    sizeof (uintptr_t) == 4 ? 43 : 35,
   1094 			    "DESCRIPTION");
   1095 
   1096 		mdb_printf("%0?p ", addr);
   1097 
   1098 		switch (vdev.vdev_state) {
   1099 		case VDEV_STATE_CLOSED:
   1100 			state = "CLOSED";
   1101 			break;
   1102 		case VDEV_STATE_OFFLINE:
   1103 			state = "OFFLINE";
   1104 			break;
   1105 		case VDEV_STATE_CANT_OPEN:
   1106 			state = "CANT_OPEN";
   1107 			break;
   1108 		case VDEV_STATE_DEGRADED:
   1109 			state = "DEGRADED";
   1110 			break;
   1111 		case VDEV_STATE_HEALTHY:
   1112 			state = "HEALTHY";
   1113 			break;
   1114 		case VDEV_STATE_REMOVED:
   1115 			state = "REMOVED";
   1116 			break;
   1117 		case VDEV_STATE_FAULTED:
   1118 			state = "FAULTED";
   1119 			break;
   1120 		default:
   1121 			state = "UNKNOWN";
   1122 			break;
   1123 		}
   1124 
   1125 		switch (vdev.vdev_stat.vs_aux) {
   1126 		case VDEV_AUX_NONE:
   1127 			aux = "-";
   1128 			break;
   1129 		case VDEV_AUX_OPEN_FAILED:
   1130 			aux = "OPEN_FAILED";
   1131 			break;
   1132 		case VDEV_AUX_CORRUPT_DATA:
   1133 			aux = "CORRUPT_DATA";
   1134 			break;
   1135 		case VDEV_AUX_NO_REPLICAS:
   1136 			aux = "NO_REPLICAS";
   1137 			break;
   1138 		case VDEV_AUX_BAD_GUID_SUM:
   1139 			aux = "BAD_GUID_SUM";
   1140 			break;
   1141 		case VDEV_AUX_TOO_SMALL:
   1142 			aux = "TOO_SMALL";
   1143 			break;
   1144 		case VDEV_AUX_BAD_LABEL:
   1145 			aux = "BAD_LABEL";
   1146 			break;
   1147 		case VDEV_AUX_VERSION_NEWER:
   1148 			aux = "VERS_NEWER";
   1149 			break;
   1150 		case VDEV_AUX_VERSION_OLDER:
   1151 			aux = "VERS_OLDER";
   1152 			break;
   1153 		case VDEV_AUX_SPARED:
   1154 			aux = "SPARED";
   1155 			break;
   1156 		case VDEV_AUX_ERR_EXCEEDED:
   1157 			aux = "ERR_EXCEEDED";
   1158 			break;
   1159 		case VDEV_AUX_IO_FAILURE:
   1160 			aux = "IO_FAILURE";
   1161 			break;
   1162 		case VDEV_AUX_BAD_LOG:
   1163 			aux = "BAD_LOG";
   1164 			break;
   1165 		case VDEV_AUX_EXTERNAL:
   1166 			aux = "EXTERNAL";
   1167 			break;
   1168 		case VDEV_AUX_SPLIT_POOL:
   1169 			aux = "SPLIT_POOL";
   1170 			break;
   1171 		default:
   1172 			aux = "UNKNOWN";
   1173 			break;
   1174 		}
   1175 
   1176 		mdb_printf("%-9s %-12s %*s%s\n", state, aux, depth, "", desc);
   1177 
   1178 		if (stats) {
   1179 			vdev_stat_t *vs = &vdev.vdev_stat;
   1180 			int i;
   1181 
   1182 			mdb_inc_indent(4);
   1183 			mdb_printf("\n");
   1184 			mdb_printf("%<u>       %12s %12s %12s %12s "
   1185 			    "%12s%</u>\n", "READ", "WRITE", "FREE", "CLAIM",
   1186 			    "IOCTL");
   1187 			mdb_printf("OPS     ");
   1188 			for (i = 1; i < ZIO_TYPES; i++)
   1189 				mdb_printf("%11#llx%s", vs->vs_ops[i],
   1190 				    i == ZIO_TYPES - 1 ? "" : "  ");
   1191 			mdb_printf("\n");
   1192 			mdb_printf("BYTES   ");
   1193 			for (i = 1; i < ZIO_TYPES; i++)
   1194 				mdb_printf("%11#llx%s", vs->vs_bytes[i],
   1195 				    i == ZIO_TYPES - 1 ? "" : "  ");
   1196 
   1197 
   1198 			mdb_printf("\n");
   1199 			mdb_printf("EREAD    %10#llx\n", vs->vs_read_errors);
   1200 			mdb_printf("EWRITE   %10#llx\n", vs->vs_write_errors);
   1201 			mdb_printf("ECKSUM   %10#llx\n",
   1202 			    vs->vs_checksum_errors);
   1203 			mdb_dec_indent(4);
   1204 		}
   1205 
   1206 		if (stats)
   1207 			mdb_printf("\n");
   1208 	}
   1209 
   1210 	children = vdev.vdev_children;
   1211 
   1212 	if (children == 0 || !recursive)
   1213 		return (DCMD_OK);
   1214 
   1215 	child = mdb_alloc(children * sizeof (void *), UM_SLEEP | UM_GC);
   1216 	if (mdb_vread(child, children * sizeof (void *),
   1217 	    (uintptr_t)vdev.vdev_child) == -1) {
   1218 		mdb_warn("failed to read vdev children at %p", vdev.vdev_child);
   1219 		return (DCMD_ERR);
   1220 	}
   1221 
   1222 	for (c = 0; c < children; c++) {
   1223 		if (do_print_vdev(child[c], flags, depth + 2, stats,
   1224 		    recursive))
   1225 			return (DCMD_ERR);
   1226 	}
   1227 
   1228 	return (DCMD_OK);
   1229 }
   1230 
   1231 static int
   1232 vdev_print(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
   1233 {
   1234 	int recursive = FALSE;
   1235 	int stats = FALSE;
   1236 	uint64_t depth = 0;
   1237 
   1238 	if (mdb_getopts(argc, argv,
   1239 	    'r', MDB_OPT_SETBITS, TRUE, &recursive,
   1240 	    'e', MDB_OPT_SETBITS, TRUE, &stats,
   1241 	    'd', MDB_OPT_UINT64, &depth,
   1242 	    NULL) != argc)
   1243 		return (DCMD_USAGE);
   1244 
   1245 	if (!(flags & DCMD_ADDRSPEC)) {
   1246 		mdb_warn("no vdev_t address given\n");
   1247 		return (DCMD_ERR);
   1248 	}
   1249 
   1250 	return (do_print_vdev(addr, flags, (int)depth, stats, recursive));
   1251 }
   1252 
   1253 typedef struct metaslab_walk_data {
   1254 	uint64_t mw_numvdevs;
   1255 	uintptr_t *mw_vdevs;
   1256 	int mw_curvdev;
   1257 	uint64_t mw_nummss;
   1258 	uintptr_t *mw_mss;
   1259 	int mw_curms;
   1260 } metaslab_walk_data_t;
   1261 
   1262 static int
   1263 metaslab_walk_step(mdb_walk_state_t *wsp)
   1264 {
   1265 	metaslab_walk_data_t *mw = wsp->walk_data;
   1266 	metaslab_t ms;
   1267 	uintptr_t msp;
   1268 
   1269 	if (mw->mw_curvdev >= mw->mw_numvdevs)
   1270 		return (WALK_DONE);
   1271 
   1272 	if (mw->mw_mss == NULL) {
   1273 		uintptr_t mssp;
   1274 		uintptr_t vdevp;
   1275 
   1276 		ASSERT(mw->mw_curms == 0);
   1277 		ASSERT(mw->mw_nummss == 0);
   1278 
   1279 		vdevp = mw->mw_vdevs[mw->mw_curvdev];
   1280 		if (GETMEMB(vdevp, struct vdev, vdev_ms, mssp) ||
   1281 		    GETMEMB(vdevp, struct vdev, vdev_ms_count, mw->mw_nummss)) {
   1282 			return (WALK_ERR);
   1283 		}
   1284 
   1285 		mw->mw_mss = mdb_alloc(mw->mw_nummss * sizeof (void*),
   1286 		    UM_SLEEP | UM_GC);
   1287 		if (mdb_vread(mw->mw_mss, mw->mw_nummss * sizeof (void*),
   1288 		    mssp) == -1) {
   1289 			mdb_warn("failed to read vdev_ms at %p", mssp);
   1290 			return (WALK_ERR);
   1291 		}
   1292 	}
   1293 
   1294 	if (mw->mw_curms >= mw->mw_nummss) {
   1295 		mw->mw_mss = NULL;
   1296 		mw->mw_curms = 0;
   1297 		mw->mw_nummss = 0;
   1298 		mw->mw_curvdev++;
   1299 		return (WALK_NEXT);
   1300 	}
   1301 
   1302 	msp = mw->mw_mss[mw->mw_curms];
   1303 	if (mdb_vread(&ms, sizeof (metaslab_t), msp) == -1) {
   1304 		mdb_warn("failed to read metaslab_t at %p", msp);
   1305 		return (WALK_ERR);
   1306 	}
   1307 
   1308 	mw->mw_curms++;
   1309 
   1310 	return (wsp->walk_callback(msp, &ms, wsp->walk_cbdata));
   1311 }
   1312 
   1313 /* ARGSUSED */
   1314 static int
   1315 metaslab_walk_init(mdb_walk_state_t *wsp)
   1316 {
   1317 	metaslab_walk_data_t *mw;
   1318 	uintptr_t root_vdevp;
   1319 	uintptr_t childp;
   1320 
   1321 	if (wsp->walk_addr == NULL) {
   1322 		mdb_warn("must supply address of spa_t\n");
   1323 		return (WALK_ERR);
   1324 	}
   1325 
   1326 	mw = mdb_zalloc(sizeof (metaslab_walk_data_t), UM_SLEEP | UM_GC);
   1327 
   1328 	if (GETMEMB(wsp->walk_addr, struct spa, spa_root_vdev, root_vdevp) ||
   1329 	    GETMEMB(root_vdevp, struct vdev, vdev_children, mw->mw_numvdevs) ||
   1330 	    GETMEMB(root_vdevp, struct vdev, vdev_child, childp)) {
   1331 		return (DCMD_ERR);
   1332 	}
   1333 
   1334 	mw->mw_vdevs = mdb_alloc(mw->mw_numvdevs * sizeof (void *),
   1335 	    UM_SLEEP | UM_GC);
   1336 	if (mdb_vread(mw->mw_vdevs, mw->mw_numvdevs * sizeof (void *),
   1337 	    childp) == -1) {
   1338 		mdb_warn("failed to read root vdev children at %p", childp);
   1339 		return (DCMD_ERR);
   1340 	}
   1341 
   1342 	wsp->walk_data = mw;
   1343 
   1344 	return (WALK_NEXT);
   1345 }
   1346 
   1347 typedef struct mdb_spa {
   1348 	uintptr_t spa_dsl_pool;
   1349 	uintptr_t spa_root_vdev;
   1350 } mdb_spa_t;
   1351 
   1352 typedef struct mdb_dsl_dir {
   1353 	uintptr_t dd_phys;
   1354 	int64_t dd_space_towrite[TXG_SIZE];
   1355 } mdb_dsl_dir_t;
   1356 
   1357 typedef struct mdb_dsl_dir_phys {
   1358 	uint64_t dd_used_bytes;
   1359 	uint64_t dd_compressed_bytes;
   1360 	uint64_t dd_uncompressed_bytes;
   1361 } mdb_dsl_dir_phys_t;
   1362 
   1363 typedef struct mdb_vdev {
   1364 	uintptr_t vdev_parent;
   1365 	uintptr_t vdev_ms;
   1366 	uint64_t vdev_ms_count;
   1367 	vdev_stat_t vdev_stat;
   1368 } mdb_vdev_t;
   1369 
   1370 typedef struct mdb_metaslab {
   1371 	space_map_t ms_allocmap[TXG_SIZE];
   1372 	space_map_t ms_freemap[TXG_SIZE];
   1373 	space_map_t ms_map;
   1374 	space_map_obj_t ms_smo;
   1375 	space_map_obj_t ms_smo_syncing;
   1376 } mdb_metaslab_t;
   1377 
   1378 typedef struct space_data {
   1379 	uint64_t ms_allocmap[TXG_SIZE];
   1380 	uint64_t ms_freemap[TXG_SIZE];
   1381 	uint64_t ms_map;
   1382 	uint64_t avail;
   1383 	uint64_t nowavail;
   1384 } space_data_t;
   1385 
   1386 /* ARGSUSED */
   1387 static int
   1388 space_cb(uintptr_t addr, const void *unknown, void *arg)
   1389 {
   1390 	space_data_t *sd = arg;
   1391 	mdb_metaslab_t ms;
   1392 
   1393 	if (GETMEMB(addr, struct metaslab, ms_allocmap, ms.ms_allocmap) ||
   1394 	    GETMEMB(addr, struct metaslab, ms_freemap, ms.ms_freemap) ||
   1395 	    GETMEMB(addr, struct metaslab, ms_map, ms.ms_map) ||
   1396 	    GETMEMB(addr, struct metaslab, ms_smo, ms.ms_smo) ||
   1397 	    GETMEMB(addr, struct metaslab, ms_smo_syncing, ms.ms_smo_syncing)) {
   1398 		return (WALK_ERR);
   1399 	}
   1400 
   1401 	sd->ms_allocmap[0] += ms.ms_allocmap[0].sm_space;
   1402 	sd->ms_allocmap[1] += ms.ms_allocmap[1].sm_space;
   1403 	sd->ms_allocmap[2] += ms.ms_allocmap[2].sm_space;
   1404 	sd->ms_allocmap[3] += ms.ms_allocmap[3].sm_space;
   1405 	sd->ms_freemap[0] += ms.ms_freemap[0].sm_space;
   1406 	sd->ms_freemap[1] += ms.ms_freemap[1].sm_space;
   1407 	sd->ms_freemap[2] += ms.ms_freemap[2].sm_space;
   1408 	sd->ms_freemap[3] += ms.ms_freemap[3].sm_space;
   1409 	sd->ms_map += ms.ms_map.sm_space;
   1410 	sd->avail += ms.ms_map.sm_size - ms.ms_smo.smo_alloc;
   1411 	sd->nowavail += ms.ms_map.sm_size - ms.ms_smo_syncing.smo_alloc;
   1412 
   1413 	return (WALK_NEXT);
   1414 }
   1415 
   1416 /*
   1417  * ::spa_space [-b]
   1418  *
   1419  * Given a spa_t, print out it's on-disk space usage and in-core
   1420  * estimates of future usage.  If -b is given, print space in bytes.
   1421  * Otherwise print in megabytes.
   1422  */
   1423 /* ARGSUSED */
   1424 static int
   1425 spa_space(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
   1426 {
   1427 	mdb_spa_t spa;
   1428 	uintptr_t dp_root_dir;
   1429 	mdb_dsl_dir_t dd;
   1430 	mdb_dsl_dir_phys_t dsp;
   1431 	uint64_t children;
   1432 	uintptr_t childaddr;
   1433 	space_data_t sd;
   1434 	int shift = 20;
   1435 	char *suffix = "M";
   1436 	int bits = FALSE;
   1437 
   1438 	if (mdb_getopts(argc, argv, 'b', MDB_OPT_SETBITS, TRUE, &bits, NULL) !=
   1439 	    argc)
   1440 		return (DCMD_USAGE);
   1441 	if (!(flags & DCMD_ADDRSPEC))
   1442 		return (DCMD_USAGE);
   1443 
   1444 	if (bits) {
   1445 		shift = 0;
   1446 		suffix = "";
   1447 	}
   1448 
   1449 	if (GETMEMB(addr, struct spa, spa_dsl_pool, spa.spa_dsl_pool) ||
   1450 	    GETMEMB(addr, struct spa, spa_root_vdev, spa.spa_root_vdev) ||
   1451 	    GETMEMB(spa.spa_root_vdev, struct vdev, vdev_children, children) ||
   1452 	    GETMEMB(spa.spa_root_vdev, struct vdev, vdev_child, childaddr) ||
   1453 	    GETMEMB(spa.spa_dsl_pool, struct dsl_pool,
   1454 	    dp_root_dir, dp_root_dir) ||
   1455 	    GETMEMB(dp_root_dir, struct dsl_dir, dd_phys, dd.dd_phys) ||
   1456 	    GETMEMB(dp_root_dir, struct dsl_dir,
   1457 	    dd_space_towrite, dd.dd_space_towrite) ||
   1458 	    GETMEMB(dd.dd_phys, struct dsl_dir_phys,
   1459 	    dd_used_bytes, dsp.dd_used_bytes) ||
   1460 	    GETMEMB(dd.dd_phys, struct dsl_dir_phys,
   1461 	    dd_compressed_bytes, dsp.dd_compressed_bytes) ||
   1462 	    GETMEMB(dd.dd_phys, struct dsl_dir_phys,
   1463 	    dd_uncompressed_bytes, dsp.dd_uncompressed_bytes)) {
   1464 		return (DCMD_ERR);
   1465 	}
   1466 
   1467 	mdb_printf("dd_space_towrite = %llu%s %llu%s %llu%s %llu%s\n",
   1468 	    dd.dd_space_towrite[0] >> shift, suffix,
   1469 	    dd.dd_space_towrite[1] >> shift, suffix,
   1470 	    dd.dd_space_towrite[2] >> shift, suffix,
   1471 	    dd.dd_space_towrite[3] >> shift, suffix);
   1472 
   1473 	mdb_printf("dd_phys.dd_used_bytes = %llu%s\n",
   1474 	    dsp.dd_used_bytes >> shift, suffix);
   1475 	mdb_printf("dd_phys.dd_compressed_bytes = %llu%s\n",
   1476 	    dsp.dd_compressed_bytes >> shift, suffix);
   1477 	mdb_printf("dd_phys.dd_uncompressed_bytes = %llu%s\n",
   1478 	    dsp.dd_uncompressed_bytes >> shift, suffix);
   1479 
   1480 	bzero(&sd, sizeof (sd));
   1481 	if (mdb_pwalk("metaslab", space_cb, &sd, addr) != 0) {
   1482 		mdb_warn("can't walk metaslabs");
   1483 		return (DCMD_ERR);
   1484 	}
   1485 
   1486 	mdb_printf("ms_allocmap = %llu%s %llu%s %llu%s %llu%s\n",
   1487 	    sd.ms_allocmap[0] >> shift, suffix,
   1488 	    sd.ms_allocmap[1] >> shift, suffix,
   1489 	    sd.ms_allocmap[2] >> shift, suffix,
   1490 	    sd.ms_allocmap[3] >> shift, suffix);
   1491 	mdb_printf("ms_freemap = %llu%s %llu%s %llu%s %llu%s\n",
   1492 	    sd.ms_freemap[0] >> shift, suffix,
   1493 	    sd.ms_freemap[1] >> shift, suffix,
   1494 	    sd.ms_freemap[2] >> shift, suffix,
   1495 	    sd.ms_freemap[3] >> shift, suffix);
   1496 	mdb_printf("ms_map = %llu%s\n", sd.ms_map >> shift, suffix);
   1497 	mdb_printf("last synced avail = %llu%s\n", sd.avail >> shift, suffix);
   1498 	mdb_printf("current syncing avail = %llu%s\n",
   1499 	    sd.nowavail >> shift, suffix);
   1500 
   1501 	return (DCMD_OK);
   1502 }
   1503 
   1504 /*
   1505  * ::spa_verify
   1506  *
   1507  * Given a spa_t, verify that that the pool is self-consistent.
   1508  * Currently, it only checks to make sure that the vdev tree exists.
   1509  */
   1510 /* ARGSUSED */
   1511 static int
   1512 spa_verify(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
   1513 {
   1514 	spa_t spa;
   1515 
   1516 	if (argc != 0 || !(flags & DCMD_ADDRSPEC))
   1517 		return (DCMD_USAGE);
   1518 
   1519 	if (mdb_vread(&spa, sizeof (spa), addr) == -1) {
   1520 		mdb_warn("failed to read spa_t at %p", addr);
   1521 		return (DCMD_ERR);
   1522 	}
   1523 
   1524 	if (spa.spa_root_vdev == NULL) {
   1525 		mdb_printf("no vdev tree present\n");
   1526 		return (DCMD_OK);
   1527 	}
   1528 
   1529 	return (DCMD_OK);
   1530 }
   1531 
   1532 static int
   1533 spa_print_aux(spa_aux_vdev_t *sav, uint_t flags, mdb_arg_t *v,
   1534     const char *name)
   1535 {
   1536 	uintptr_t *aux;
   1537 	size_t len;
   1538 	int ret, i;
   1539 
   1540 	/*
   1541 	 * Iterate over aux vdevs and print those out as well.  This is a
   1542 	 * little annoying because we don't have a root vdev to pass to ::vdev.
   1543 	 * Instead, we print a single line and then call it for each child
   1544 	 * vdev.
   1545 	 */
   1546 	if (sav->sav_count != 0) {
   1547 		v[1].a_type = MDB_TYPE_STRING;
   1548 		v[1].a_un.a_str = "-d";
   1549 		v[2].a_type = MDB_TYPE_IMMEDIATE;
   1550 		v[2].a_un.a_val = 2;
   1551 
   1552 		len = sav->sav_count * sizeof (uintptr_t);
   1553 		aux = mdb_alloc(len, UM_SLEEP);
   1554 		if (mdb_vread(aux, len,
   1555 		    (uintptr_t)sav->sav_vdevs) == -1) {
   1556 			mdb_free(aux, len);
   1557 			mdb_warn("failed to read l2cache vdevs at %p",
   1558 			    sav->sav_vdevs);
   1559 			return (DCMD_ERR);
   1560 		}
   1561 
   1562 		mdb_printf("%-?s %-9s %-12s %s\n", "-", "-", "-", name);
   1563 
   1564 		for (i = 0; i < sav->sav_count; i++) {
   1565 			ret = mdb_call_dcmd("vdev", aux[i], flags, 3, v);
   1566 			if (ret != DCMD_OK) {
   1567 				mdb_free(aux, len);
   1568 				return (ret);
   1569 			}
   1570 		}
   1571 
   1572 		mdb_free(aux, len);
   1573 	}
   1574 
   1575 	return (0);
   1576 }
   1577 
   1578 /*
   1579  * ::spa_vdevs
   1580  *
   1581  * 	-e	Include error stats
   1582  *
   1583  * Print out a summarized list of vdevs for the given spa_t.
   1584  * This is accomplished by invoking "::vdev -re" on the root vdev, as well as
   1585  * iterating over the cache devices.
   1586  */
   1587 /* ARGSUSED */
   1588 static int
   1589 spa_vdevs(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
   1590 {
   1591 	spa_t spa;
   1592 	mdb_arg_t v[3];
   1593 	int errors = FALSE;
   1594 	int ret;
   1595 
   1596 	if (mdb_getopts(argc, argv,
   1597 	    'e', MDB_OPT_SETBITS, TRUE, &errors,
   1598 	    NULL) != argc)
   1599 		return (DCMD_USAGE);
   1600 
   1601 	if (!(flags & DCMD_ADDRSPEC))
   1602 		return (DCMD_USAGE);
   1603 
   1604 	if (mdb_vread(&spa, sizeof (spa), addr) == -1) {
   1605 		mdb_warn("failed to read spa_t at %p", addr);
   1606 		return (DCMD_ERR);
   1607 	}
   1608 
   1609 	/*
   1610 	 * Unitialized spa_t structures can have a NULL root vdev.
   1611 	 */
   1612 	if (spa.spa_root_vdev == NULL) {
   1613 		mdb_printf("no associated vdevs\n");
   1614 		return (DCMD_OK);
   1615 	}
   1616 
   1617 	v[0].a_type = MDB_TYPE_STRING;
   1618 	v[0].a_un.a_str = errors ? "-re" : "-r";
   1619 
   1620 	ret = mdb_call_dcmd("vdev", (uintptr_t)spa.spa_root_vdev,
   1621 	    flags, 1, v);
   1622 	if (ret != DCMD_OK)
   1623 		return (ret);
   1624 
   1625 	if (spa_print_aux(&spa.spa_l2cache, flags, v, "cache") != 0 ||
   1626 	    spa_print_aux(&spa.spa_spares, flags, v, "spares") != 0)
   1627 		return (DCMD_ERR);
   1628 
   1629 	return (DCMD_OK);
   1630 }
   1631 
   1632 /*
   1633  * ::zio
   1634  *
   1635  * Print a summary of zio_t and all its children.  This is intended to display a
   1636  * zio tree, and hence we only pick the most important pieces of information for
   1637  * the main summary.  More detailed information can always be found by doing a
   1638  * '::print zio' on the underlying zio_t.  The columns we display are:
   1639  *
   1640  *	ADDRESS		TYPE	STAGE		WAITER
   1641  *
   1642  * The 'address' column is indented by one space for each depth level as we
   1643  * descend down the tree.
   1644  */
   1645 
   1646 #define	ZIO_MAXINDENT	24
   1647 #define	ZIO_MAXWIDTH	(sizeof (uintptr_t) * 2 + ZIO_MAXINDENT)
   1648 #define	ZIO_WALK_SELF	0
   1649 #define	ZIO_WALK_CHILD	1
   1650 #define	ZIO_WALK_PARENT	2
   1651 
   1652 typedef struct zio_print_args {
   1653 	int	zpa_current_depth;
   1654 	int	zpa_min_depth;
   1655 	int	zpa_max_depth;
   1656 	int	zpa_type;
   1657 	uint_t	zpa_flags;
   1658 } zio_print_args_t;
   1659 
   1660 static int zio_child_cb(uintptr_t addr, const void *unknown, void *arg);
   1661 
   1662 static int
   1663 zio_print_cb(uintptr_t addr, const void *data, void *priv)
   1664 {
   1665 	const zio_t *zio = data;
   1666 	zio_print_args_t *zpa = priv;
   1667 	mdb_ctf_id_t type_enum, stage_enum;
   1668 	int indent = zpa->zpa_current_depth;
   1669 	const char *type, *stage;
   1670 	uintptr_t laddr;
   1671 
   1672 	if (indent > ZIO_MAXINDENT)
   1673 		indent = ZIO_MAXINDENT;
   1674 
   1675 	if (mdb_ctf_lookup_by_name("enum zio_type", &type_enum) == -1 ||
   1676 	    mdb_ctf_lookup_by_name("enum zio_stage", &stage_enum) == -1) {
   1677 		mdb_warn("failed to lookup zio enums");
   1678 		return (WALK_ERR);
   1679 	}
   1680 
   1681 	if ((type = mdb_ctf_enum_name(type_enum, zio->io_type)) != NULL)
   1682 		type += sizeof ("ZIO_TYPE_") - 1;
   1683 	else
   1684 		type = "?";
   1685 
   1686 	if ((stage = mdb_ctf_enum_name(stage_enum, zio->io_stage)) != NULL)
   1687 		stage += sizeof ("ZIO_STAGE_") - 1;
   1688 	else
   1689 		stage = "?";
   1690 
   1691 	if (zpa->zpa_current_depth >= zpa->zpa_min_depth) {
   1692 		if (zpa->zpa_flags & DCMD_PIPE_OUT) {
   1693 			mdb_printf("%?p\n", addr);
   1694 		} else {
   1695 			mdb_printf("%*s%-*p %-5s %-16s ", indent, "",
   1696 			    ZIO_MAXWIDTH - indent, addr, type, stage);
   1697 			if (zio->io_waiter)
   1698 				mdb_printf("%?p\n", zio->io_waiter);
   1699 			else
   1700 				mdb_printf("-\n");
   1701 		}
   1702 	}
   1703 
   1704 	if (zpa->zpa_current_depth >= zpa->zpa_max_depth)
   1705 		return (WALK_NEXT);
   1706 
   1707 	if (zpa->zpa_type == ZIO_WALK_PARENT)
   1708 		laddr = addr + OFFSETOF(zio_t, io_parent_list);
   1709 	else
   1710 		laddr = addr + OFFSETOF(zio_t, io_child_list);
   1711 
   1712 	zpa->zpa_current_depth++;
   1713 	if (mdb_pwalk("list", zio_child_cb, zpa, laddr) != 0) {
   1714 		mdb_warn("failed to walk zio_t children at %p\n", laddr);
   1715 		return (WALK_ERR);
   1716 	}
   1717 	zpa->zpa_current_depth--;
   1718 
   1719 	return (WALK_NEXT);
   1720 }
   1721 
   1722 /* ARGSUSED */
   1723 static int
   1724 zio_child_cb(uintptr_t addr, const void *unknown, void *arg)
   1725 {
   1726 	zio_link_t zl;
   1727 	zio_t zio;
   1728 	uintptr_t ziop;
   1729 	zio_print_args_t *zpa = arg;
   1730 
   1731 	if (mdb_vread(&zl, sizeof (zl), addr) == -1) {
   1732 		mdb_warn("failed to read zio_link_t at %p", addr);
   1733 		return (WALK_ERR);
   1734 	}
   1735 
   1736 	if (zpa->zpa_type == ZIO_WALK_PARENT)
   1737 		ziop = (uintptr_t)zl.zl_parent;
   1738 	else
   1739 		ziop = (uintptr_t)zl.zl_child;
   1740 
   1741 	if (mdb_vread(&zio, sizeof (zio_t), ziop) == -1) {
   1742 		mdb_warn("failed to read zio_t at %p", ziop);
   1743 		return (WALK_ERR);
   1744 	}
   1745 
   1746 	return (zio_print_cb(ziop, &zio, arg));
   1747 }
   1748 
   1749 /* ARGSUSED */
   1750 static int
   1751 zio_print(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
   1752 {
   1753 	zio_t zio;
   1754 	zio_print_args_t zpa = { 0 };
   1755 
   1756 	if (!(flags & DCMD_ADDRSPEC))
   1757 		return (DCMD_USAGE);
   1758 
   1759 	if (mdb_getopts(argc, argv,
   1760 	    'r', MDB_OPT_SETBITS, INT_MAX, &zpa.zpa_max_depth,
   1761 	    'c', MDB_OPT_SETBITS, ZIO_WALK_CHILD, &zpa.zpa_type,
   1762 	    'p', MDB_OPT_SETBITS, ZIO_WALK_PARENT, &zpa.zpa_type,
   1763 	    NULL) != argc)
   1764 		return (DCMD_USAGE);
   1765 
   1766 	zpa.zpa_flags = flags;
   1767 	if (zpa.zpa_max_depth != 0) {
   1768 		if (zpa.zpa_type == ZIO_WALK_SELF)
   1769 			zpa.zpa_type = ZIO_WALK_CHILD;
   1770 	} else if (zpa.zpa_type != ZIO_WALK_SELF) {
   1771 		zpa.zpa_min_depth = 1;
   1772 		zpa.zpa_max_depth = 1;
   1773 	}
   1774 
   1775 	if (mdb_vread(&zio, sizeof (zio_t), addr) == -1) {
   1776 		mdb_warn("failed to read zio_t at %p", addr);
   1777 		return (DCMD_ERR);
   1778 	}
   1779 
   1780 	if (!(flags & DCMD_PIPE_OUT) && DCMD_HDRSPEC(flags))
   1781 		mdb_printf("%<u>%-*s %-5s %-16s %-?s%</u>\n", ZIO_MAXWIDTH,
   1782 		    "ADDRESS", "TYPE", "STAGE", "WAITER");
   1783 
   1784 	if (zio_print_cb(addr, &zio, &zpa) != WALK_NEXT)
   1785 		return (DCMD_ERR);
   1786 
   1787 	return (DCMD_OK);
   1788 }
   1789 
   1790 /*
   1791  * [addr]::zio_state
   1792  *
   1793  * Print a summary of all zio_t structures on the system, or for a particular
   1794  * pool.  This is equivalent to '::walk zio_root | ::zio'.
   1795  */
   1796 /*ARGSUSED*/
   1797 static int
   1798 zio_state(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
   1799 {
   1800 	/*
   1801 	 * MDB will remember the last address of the pipeline, so if we don't
   1802 	 * zero this we'll end up trying to walk zio structures for a
   1803 	 * non-existent spa_t.
   1804 	 */
   1805 	if (!(flags & DCMD_ADDRSPEC))
   1806 		addr = 0;
   1807 
   1808 	return (mdb_pwalk_dcmd("zio_root", "zio", argc, argv, addr));
   1809 }
   1810 
   1811 typedef struct txg_list_walk_data {
   1812 	uintptr_t lw_head[TXG_SIZE];
   1813 	int	lw_txgoff;
   1814 	int	lw_maxoff;
   1815 	size_t	lw_offset;
   1816 	void	*lw_obj;
   1817 } txg_list_walk_data_t;
   1818 
   1819 static int
   1820 txg_list_walk_init_common(mdb_walk_state_t *wsp, int txg, int maxoff)
   1821 {
   1822 	txg_list_walk_data_t *lwd;
   1823 	txg_list_t list;
   1824 	int i;
   1825 
   1826 	lwd = mdb_alloc(sizeof (txg_list_walk_data_t), UM_SLEEP | UM_GC);
   1827 	if (mdb_vread(&list, sizeof (txg_list_t), wsp->walk_addr) == -1) {
   1828 		mdb_warn("failed to read txg_list_t at %#lx", wsp->walk_addr);
   1829 		return (WALK_ERR);
   1830 	}
   1831 
   1832 	for (i = 0; i < TXG_SIZE; i++)
   1833 		lwd->lw_head[i] = (uintptr_t)list.tl_head[i];
   1834 	lwd->lw_offset = list.tl_offset;
   1835 	lwd->lw_obj = mdb_alloc(lwd->lw_offset + sizeof (txg_node_t),
   1836 	    UM_SLEEP | UM_GC);
   1837 	lwd->lw_txgoff = txg;
   1838 	lwd->lw_maxoff = maxoff;
   1839 
   1840 	wsp->walk_addr = lwd->lw_head[lwd->lw_txgoff];
   1841 	wsp->walk_data = lwd;
   1842 
   1843 	return (WALK_NEXT);
   1844 }
   1845 
   1846 static int
   1847 txg_list_walk_init(mdb_walk_state_t *wsp)
   1848 {
   1849 	return (txg_list_walk_init_common(wsp, 0, TXG_SIZE-1));
   1850 }
   1851 
   1852 static int
   1853 txg_list0_walk_init(mdb_walk_state_t *wsp)
   1854 {
   1855 	return (txg_list_walk_init_common(wsp, 0, 0));
   1856 }
   1857 
   1858 static int
   1859 txg_list1_walk_init(mdb_walk_state_t *wsp)
   1860 {
   1861 	return (txg_list_walk_init_common(wsp, 1, 1));
   1862 }
   1863 
   1864 static int
   1865 txg_list2_walk_init(mdb_walk_state_t *wsp)
   1866 {
   1867 	return (txg_list_walk_init_common(wsp, 2, 2));
   1868 }
   1869 
   1870 static int
   1871 txg_list3_walk_init(mdb_walk_state_t *wsp)
   1872 {
   1873 	return (txg_list_walk_init_common(wsp, 3, 3));
   1874 }
   1875 
   1876 static int
   1877 txg_list_walk_step(mdb_walk_state_t *wsp)
   1878 {
   1879 	txg_list_walk_data_t *lwd = wsp->walk_data;
   1880 	uintptr_t addr;
   1881 	txg_node_t *node;
   1882 	int status;
   1883 
   1884 	while (wsp->walk_addr == NULL && lwd->lw_txgoff < lwd->lw_maxoff) {
   1885 		lwd->lw_txgoff++;
   1886 		wsp->walk_addr = lwd->lw_head[lwd->lw_txgoff];
   1887 	}
   1888 
   1889 	if (wsp->walk_addr == NULL)
   1890 		return (WALK_DONE);
   1891 
   1892 	addr = wsp->walk_addr - lwd->lw_offset;
   1893 
   1894 	if (mdb_vread(lwd->lw_obj,
   1895 	    lwd->lw_offset + sizeof (txg_node_t), addr) == -1) {
   1896 		mdb_warn("failed to read list element at %#lx", addr);
   1897 		return (WALK_ERR);
   1898 	}
   1899 
   1900 	status = wsp->walk_callback(addr, lwd->lw_obj, wsp->walk_cbdata);
   1901 	node = (txg_node_t *)((uintptr_t)lwd->lw_obj + lwd->lw_offset);
   1902 	wsp->walk_addr = (uintptr_t)node->tn_next[lwd->lw_txgoff];
   1903 
   1904 	return (status);
   1905 }
   1906 
   1907 /*
   1908  * ::walk spa
   1909  *
   1910  * Walk all named spa_t structures in the namespace.  This is nothing more than
   1911  * a layered avl walk.
   1912  */
   1913 static int
   1914 spa_walk_init(mdb_walk_state_t *wsp)
   1915 {
   1916 	GElf_Sym sym;
   1917 
   1918 	if (wsp->walk_addr != NULL) {
   1919 		mdb_warn("spa walk only supports global walks\n");
   1920 		return (WALK_ERR);
   1921 	}
   1922 
   1923 	if (mdb_lookup_by_obj(ZFS_OBJ_NAME, "spa_namespace_avl", &sym) == -1) {
   1924 		mdb_warn("failed to find symbol 'spa_namespace_avl'");
   1925 		return (WALK_ERR);
   1926 	}
   1927 
   1928 	wsp->walk_addr = (uintptr_t)sym.st_value;
   1929 
   1930 	if (mdb_layered_walk("avl", wsp) == -1) {
   1931 		mdb_warn("failed to walk 'avl'\n");
   1932 		return (WALK_ERR);
   1933 	}
   1934 
   1935 	return (WALK_NEXT);
   1936 }
   1937 
   1938 static int
   1939 spa_walk_step(mdb_walk_state_t *wsp)
   1940 {
   1941 	spa_t	spa;
   1942 
   1943 	if (mdb_vread(&spa, sizeof (spa), wsp->walk_addr) == -1) {
   1944 		mdb_warn("failed to read spa_t at %p", wsp->walk_addr);
   1945 		return (WALK_ERR);
   1946 	}
   1947 
   1948 	return (wsp->walk_callback(wsp->walk_addr, &spa, wsp->walk_cbdata));
   1949 }
   1950 
   1951 /*
   1952  * [addr]::walk zio
   1953  *
   1954  * Walk all active zio_t structures on the system.  This is simply a layered
   1955  * walk on top of ::walk zio_cache, with the optional ability to limit the
   1956  * structures to a particular pool.
   1957  */
   1958 static int
   1959 zio_walk_init(mdb_walk_state_t *wsp)
   1960 {
   1961 	wsp->walk_data = (void *)wsp->walk_addr;
   1962 
   1963 	if (mdb_layered_walk("zio_cache", wsp) == -1) {
   1964 		mdb_warn("failed to walk 'zio_cache'\n");
   1965 		return (WALK_ERR);
   1966 	}
   1967 
   1968 	return (WALK_NEXT);
   1969 }
   1970 
   1971 static int
   1972 zio_walk_step(mdb_walk_state_t *wsp)
   1973 {
   1974 	zio_t zio;
   1975 
   1976 	if (mdb_vread(&zio, sizeof (zio), wsp->walk_addr) == -1) {
   1977 		mdb_warn("failed to read zio_t at %p", wsp->walk_addr);
   1978 		return (WALK_ERR);
   1979 	}
   1980 
   1981 	if (wsp->walk_data != NULL && wsp->walk_data != zio.io_spa)
   1982 		return (WALK_NEXT);
   1983 
   1984 	return (wsp->walk_callback(wsp->walk_addr, &zio, wsp->walk_cbdata));
   1985 }
   1986 
   1987 /*
   1988  * [addr]::walk zio_root
   1989  *
   1990  * Walk only root zio_t structures, optionally for a particular spa_t.
   1991  */
   1992 static int
   1993 zio_walk_root_step(mdb_walk_state_t *wsp)
   1994 {
   1995 	zio_t zio;
   1996 
   1997 	if (mdb_vread(&zio, sizeof (zio), wsp->walk_addr) == -1) {
   1998 		mdb_warn("failed to read zio_t at %p", wsp->walk_addr);
   1999 		return (WALK_ERR);
   2000 	}
   2001 
   2002 	if (wsp->walk_data != NULL && wsp->walk_data != zio.io_spa)
   2003 		return (WALK_NEXT);
   2004 
   2005 	/* If the parent list is not empty, ignore */
   2006 	if (zio.io_parent_list.list_head.list_next !=
   2007 	    &((zio_t *)wsp->walk_addr)->io_parent_list.list_head)
   2008 		return (WALK_NEXT);
   2009 
   2010 	return (wsp->walk_callback(wsp->walk_addr, &zio, wsp->walk_cbdata));
   2011 }
   2012 
   2013 #define	NICENUM_BUFLEN 6
   2014 
   2015 static int
   2016 snprintfrac(char *buf, int len,
   2017     uint64_t numerator, uint64_t denom, int frac_digits)
   2018 {
   2019 	int mul = 1;
   2020 	int whole, frac, i;
   2021 
   2022 	for (i = frac_digits; i; i--)
   2023 		mul *= 10;
   2024 	whole = numerator / denom;
   2025 	frac = mul * numerator / denom - mul * whole;
   2026 	return (mdb_snprintf(buf, len, "%u.%0*u", whole, frac_digits, frac));
   2027 }
   2028 
   2029 static void
   2030 mdb_nicenum(uint64_t num, char *buf)
   2031 {
   2032 	uint64_t n = num;
   2033 	int index = 0;
   2034 	char *u;
   2035 
   2036 	while (n >= 1024) {
   2037 		n = (n + (1024 / 2)) / 1024; /* Round up or down */
   2038 		index++;
   2039 	}
   2040 
   2041 	u = &" \0K\0M\0G\0T\0P\0E\0"[index*2];
   2042 
   2043 	if (index == 0) {
   2044 		(void) mdb_snprintf(buf, NICENUM_BUFLEN, "%llu",
   2045 		    (u_longlong_t)n);
   2046 	} else if (n < 10 && (num & (num - 1)) != 0) {
   2047 		(void) snprintfrac(buf, NICENUM_BUFLEN,
   2048 		    num, 1ULL << 10 * index, 2);
   2049 		strcat(buf, u);
   2050 	} else if (n < 100 && (num & (num - 1)) != 0) {
   2051 		(void) snprintfrac(buf, NICENUM_BUFLEN,
   2052 		    num, 1ULL << 10 * index, 1);
   2053 		strcat(buf, u);
   2054 	} else {
   2055 		(void) mdb_snprintf(buf, NICENUM_BUFLEN, "%llu%s",
   2056 		    (u_longlong_t)n, u);
   2057 	}
   2058 }
   2059 
   2060 /*
   2061  * ::zfs_blkstats
   2062  *
   2063  * 	-v	print verbose per-level information
   2064  *
   2065  */
   2066 static int
   2067 zfs_blkstats(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
   2068 {
   2069 	boolean_t verbose = B_FALSE;
   2070 	zfs_all_blkstats_t stats;
   2071 	dmu_object_type_t t;
   2072 	zfs_blkstat_t *tzb;
   2073 	uint64_t ditto;
   2074 	dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES + 10];
   2075 	/* +10 in case it grew */
   2076 
   2077 	if (mdb_readvar(&dmu_ot, "dmu_ot") == -1) {
   2078 		mdb_warn("failed to read 'dmu_ot'");
   2079 		return (DCMD_ERR);
   2080 	}
   2081 
   2082 	if (mdb_getopts(argc, argv,
   2083 	    'v', MDB_OPT_SETBITS, TRUE, &verbose,
   2084 	    NULL) != argc)
   2085 		return (DCMD_USAGE);
   2086 
   2087 	if (!(flags & DCMD_ADDRSPEC))
   2088 		return (DCMD_USAGE);
   2089 
   2090 	if (GETMEMB(addr, struct spa, spa_dsl_pool, addr) ||
   2091 	    GETMEMB(addr, struct dsl_pool, dp_blkstats, addr) ||
   2092 	    mdb_vread(&stats, sizeof (zfs_all_blkstats_t), addr) == -1) {
   2093 		mdb_warn("failed to read data at %p;", addr);
   2094 		mdb_printf("maybe no stats? run \"zpool scrub\" first.");
   2095 		return (DCMD_ERR);
   2096 	}
   2097 
   2098 	tzb = &stats.zab_type[DN_MAX_LEVELS][DMU_OT_NUMTYPES];
   2099 	if (tzb->zb_gangs != 0) {
   2100 		mdb_printf("Ganged blocks: %llu\n",
   2101 		    (longlong_t)tzb->zb_gangs);
   2102 	}
   2103 
   2104 	ditto = tzb->zb_ditto_2_of_2_samevdev + tzb->zb_ditto_2_of_3_samevdev +
   2105 	    tzb->zb_ditto_3_of_3_samevdev;
   2106 	if (ditto != 0) {
   2107 		mdb_printf("Dittoed blocks on same vdev: %llu\n",
   2108 		    (longlong_t)ditto);
   2109 	}
   2110 
   2111 	mdb_printf("\nBlocks\tLSIZE\tPSIZE\tASIZE"
   2112 	    "\t  avg\t comp\t%%Total\tType\n");
   2113 
   2114 	for (t = 0; t <= DMU_OT_NUMTYPES; t++) {
   2115 		char csize[NICENUM_BUFLEN], lsize[NICENUM_BUFLEN];
   2116 		char psize[NICENUM_BUFLEN], asize[NICENUM_BUFLEN];
   2117 		char avg[NICENUM_BUFLEN];
   2118 		char comp[NICENUM_BUFLEN], pct[NICENUM_BUFLEN];
   2119 		char typename[64];
   2120 		int l;
   2121 
   2122 
   2123 		if (t == DMU_OT_DEFERRED)
   2124 			strcpy(typename, "deferred free");
   2125 		else if (t == DMU_OT_TOTAL)
   2126 			strcpy(typename, "Total");
   2127 		else if (mdb_readstr(typename, sizeof (typename),
   2128 		    (uintptr_t)dmu_ot[t].ot_name) == -1) {
   2129 			mdb_warn("failed to read type name");
   2130 			return (DCMD_ERR);
   2131 		}
   2132 
   2133 		if (stats.zab_type[DN_MAX_LEVELS][t].zb_asize == 0)
   2134 			continue;
   2135 
   2136 		for (l = -1; l < DN_MAX_LEVELS; l++) {
   2137 			int level = (l == -1 ? DN_MAX_LEVELS : l);
   2138 			zfs_blkstat_t *zb = &stats.zab_type[level][t];
   2139 
   2140 			if (zb->zb_asize == 0)
   2141 				continue;
   2142 
   2143 			/*
   2144 			 * Don't print each level unless requested.
   2145 			 */
   2146 			if (!verbose && level != DN_MAX_LEVELS)
   2147 				continue;
   2148 
   2149 			/*
   2150 			 * If all the space is level 0, don't print the
   2151 			 * level 0 separately.
   2152 			 */
   2153 			if (level == 0 && zb->zb_asize ==
   2154 			    stats.zab_type[DN_MAX_LEVELS][t].zb_asize)
   2155 				continue;
   2156 
   2157 			mdb_nicenum(zb->zb_count, csize);
   2158 			mdb_nicenum(zb->zb_lsize, lsize);
   2159 			mdb_nicenum(zb->zb_psize, psize);
   2160 			mdb_nicenum(zb->zb_asize, asize);
   2161 			mdb_nicenum(zb->zb_asize / zb->zb_count, avg);
   2162 			(void) snprintfrac(comp, NICENUM_BUFLEN,
   2163 			    zb->zb_lsize, zb->zb_psize, 2);
   2164 			(void) snprintfrac(pct, NICENUM_BUFLEN,
   2165 			    100 * zb->zb_asize, tzb->zb_asize, 2);
   2166 
   2167 			mdb_printf("%6s\t%5s\t%5s\t%5s\t%5s"
   2168 			    "\t%5s\t%6s\t",
   2169 			    csize, lsize, psize, asize, avg, comp, pct);
   2170 
   2171 			if (level == DN_MAX_LEVELS)
   2172 				mdb_printf("%s\n", typename);
   2173 			else
   2174 				mdb_printf("  L%d %s\n",
   2175 				    level, typename);
   2176 		}
   2177 	}
   2178 
   2179 	return (DCMD_OK);
   2180 }
   2181 
   2182 /* ARGSUSED */
   2183 static int
   2184 reference_cb(uintptr_t addr, const void *ignored, void *arg)
   2185 {
   2186 	static int gotid;
   2187 	static mdb_ctf_id_t ref_id;
   2188 	uintptr_t ref_holder;
   2189 	uintptr_t ref_removed;
   2190 	uint64_t ref_number;
   2191 	boolean_t holder_is_str;
   2192 	char holder_str[128];
   2193 	boolean_t removed = (boolean_t)arg;
   2194 
   2195 	if (!gotid) {
   2196 		if (mdb_ctf_lookup_by_name("struct reference", &ref_id) == -1) {
   2197 			mdb_warn("couldn't find struct reference");
   2198 			return (WALK_ERR);
   2199 		}
   2200 		gotid = TRUE;
   2201 	}
   2202 
   2203 	if (GETMEMBID(addr, &ref_id, ref_holder, ref_holder) ||
   2204 	    GETMEMBID(addr, &ref_id, ref_removed, ref_removed) ||
   2205 	    GETMEMBID(addr, &ref_id, ref_number, ref_number))
   2206 		return (WALK_ERR);
   2207 
   2208 	if (mdb_readstr(holder_str, sizeof (holder_str), ref_holder) != -1) {
   2209 		char *cp;
   2210 		holder_is_str = B_TRUE;
   2211 		for (cp = holder_str; *cp; cp++) {
   2212 			if (!isprint(*cp)) {
   2213 				holder_is_str = B_FALSE;
   2214 				break;
   2215 			}
   2216 		}
   2217 	} else {
   2218 		holder_is_str = B_FALSE;
   2219 	}
   2220 
   2221 	if (removed)
   2222 		mdb_printf("removed ");
   2223 	mdb_printf("reference ");
   2224 	if (ref_number != 1)
   2225 		mdb_printf("with count=%llu ", ref_number);
   2226 	mdb_printf("with tag %p", (void*)ref_holder);
   2227 	if (holder_is_str)
   2228 		mdb_printf(" \"%s\"", holder_str);
   2229 	mdb_printf(", held at:\n");
   2230 
   2231 	(void) mdb_call_dcmd("whatis", addr, DCMD_ADDRSPEC, 0, NULL);
   2232 
   2233 	if (removed) {
   2234 		mdb_printf("removed at:\n");
   2235 		(void) mdb_call_dcmd("whatis", ref_removed,
   2236 		    DCMD_ADDRSPEC, 0, NULL);
   2237 	}
   2238 
   2239 	mdb_printf("\n");
   2240 
   2241 	return (WALK_NEXT);
   2242 }
   2243 
   2244 /* ARGSUSED */
   2245 static int
   2246 refcount(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
   2247 {
   2248 	uint64_t rc_count, rc_removed_count;
   2249 	uintptr_t rc_list, rc_removed;
   2250 	static int gotid;
   2251 	static mdb_ctf_id_t rc_id;
   2252 	ulong_t off;
   2253 
   2254 	if (!(flags & DCMD_ADDRSPEC))
   2255 		return (DCMD_USAGE);
   2256 
   2257 	if (!gotid) {
   2258 		if (mdb_ctf_lookup_by_name("struct refcount", &rc_id) == -1) {
   2259 			mdb_warn("couldn't find struct refcount");
   2260 			return (DCMD_ERR);
   2261 		}
   2262 		gotid = TRUE;
   2263 	}
   2264 
   2265 	if (GETMEMBID(addr, &rc_id, rc_count, rc_count) ||
   2266 	    GETMEMBID(addr, &rc_id, rc_removed_count, rc_removed_count))
   2267 		return (DCMD_ERR);
   2268 
   2269 	mdb_printf("refcount_t at %p has %llu current holds, "
   2270 	    "%llu recently released holds\n",
   2271 	    addr, (longlong_t)rc_count, (longlong_t)rc_removed_count);
   2272 
   2273 	if (rc_count > 0)
   2274 		mdb_printf("current holds:\n");
   2275 	if (mdb_ctf_offsetof(rc_id, "rc_list", &off) == -1)
   2276 		return (DCMD_ERR);
   2277 	rc_list = addr + off/NBBY;
   2278 	mdb_pwalk("list", reference_cb, (void*)B_FALSE, rc_list);
   2279 
   2280 	if (rc_removed_count > 0)
   2281 		mdb_printf("released holds:\n");
   2282 	if (mdb_ctf_offsetof(rc_id, "rc_removed", &off) == -1)
   2283 		return (DCMD_ERR);
   2284 	rc_removed = addr + off/NBBY;
   2285 	mdb_pwalk("list", reference_cb, (void*)B_TRUE, rc_removed);
   2286 
   2287 	return (DCMD_OK);
   2288 }
   2289 
   2290 /*
   2291  * MDB module linkage information:
   2292  *
   2293  * We declare a list of structures describing our dcmds, and a function
   2294  * named _mdb_init to return a pointer to our module information.
   2295  */
   2296 
   2297 static const mdb_dcmd_t dcmds[] = {
   2298 	{ "arc", "[-bkmg]", "print ARC variables", arc_print },
   2299 	{ "blkptr", ":", "print blkptr_t", blkptr },
   2300 	{ "dbuf", ":", "print dmu_buf_impl_t", dbuf },
   2301 	{ "dbuf_stats", ":", "dbuf stats", dbuf_stats },
   2302 	{ "dbufs",
   2303 	    "\t[-O objset_t*] [-n objset_name | \"mos\"] "
   2304 	    "[-o object | \"mdn\"] \n"
   2305 	    "\t[-l level] [-b blkid | \"bonus\"]",
   2306 	    "find dmu_buf_impl_t's that match specified criteria", dbufs },
   2307 	{ "abuf_find", "dva_word[0] dva_word[1]",
   2308 	    "find arc_buf_hdr_t of a specified DVA",
   2309 	    abuf_find },
   2310 	{ "spa", "?[-cv]", "spa_t summary", spa_print },
   2311 	{ "spa_config", ":", "print spa_t configuration", spa_print_config },
   2312 	{ "spa_verify", ":", "verify spa_t consistency", spa_verify },
   2313 	{ "spa_space", ":[-b]", "print spa_t on-disk space usage", spa_space },
   2314 	{ "spa_vdevs", ":", "given a spa_t, print vdev summary", spa_vdevs },
   2315 	{ "vdev", ":[-re]\n"
   2316 	    "\t-r display recursively\n"
   2317 	    "\t-e print statistics",
   2318 	    "vdev_t summary", vdev_print },
   2319 	{ "zio", ":[cpr]\n"
   2320 	    "\t-c display children\n"
   2321 	    "\t-p display parents\n"
   2322 	    "\t-r display recursively",
   2323 	    "zio_t summary", zio_print },
   2324 	{ "zio_state", "?", "print out all zio_t structures on system or "
   2325 	    "for a particular pool", zio_state },
   2326 	{ "zfs_blkstats", ":[-v]",
   2327 	    "given a spa_t, print block type stats from last scrub",
   2328 	    zfs_blkstats },
   2329 	{ "zfs_params", "", "print zfs tunable parameters", zfs_params },
   2330 	{ "refcount", "", "print refcount_t holders", refcount },
   2331 	{ "zap_leaf", "", "print zap_leaf_phys_t", zap_leaf },
   2332 	{ NULL }
   2333 };
   2334 
   2335 static const mdb_walker_t walkers[] = {
   2336 	/*
   2337 	 * In userland, there is no generic provider of list_t walkers, so we
   2338 	 * need to add it.
   2339 	 */
   2340 #ifndef _KERNEL
   2341 	{ LIST_WALK_NAME, LIST_WALK_DESC,
   2342 		list_walk_init, list_walk_step, list_walk_fini },
   2343 #endif
   2344 	{ "zms_freelist", "walk ZFS metaslab freelist",
   2345 		freelist_walk_init, freelist_walk_step, NULL },
   2346 	{ "txg_list", "given any txg_list_t *, walk all entries in all txgs",
   2347 		txg_list_walk_init, txg_list_walk_step, NULL },
   2348 	{ "txg_list0", "given any txg_list_t *, walk all entries in txg 0",
   2349 		txg_list0_walk_init, txg_list_walk_step, NULL },
   2350 	{ "txg_list1", "given any txg_list_t *, walk all entries in txg 1",
   2351 		txg_list1_walk_init, txg_list_walk_step, NULL },
   2352 	{ "txg_list2", "given any txg_list_t *, walk all entries in txg 2",
   2353 		txg_list2_walk_init, txg_list_walk_step, NULL },
   2354 	{ "txg_list3", "given any txg_list_t *, walk all entries in txg 3",
   2355 		txg_list3_walk_init, txg_list_walk_step, NULL },
   2356 	{ "zio", "walk all zio structures, optionally for a particular spa_t",
   2357 		zio_walk_init, zio_walk_step, NULL },
   2358 	{ "zio_root", "walk all root zio_t structures, optionally for a "
   2359 	    "particular spa_t",
   2360 		zio_walk_init, zio_walk_root_step, NULL },
   2361 	{ "spa", "walk all spa_t entries in the namespace",
   2362 		spa_walk_init, spa_walk_step, NULL },
   2363 	{ "metaslab", "given a spa_t *, walk all metaslab_t structures",
   2364 		metaslab_walk_init, metaslab_walk_step, NULL },
   2365 	{ NULL }
   2366 };
   2367 
   2368 static const mdb_modinfo_t modinfo = {
   2369 	MDB_API_VERSION, dcmds, walkers
   2370 };
   2371 
   2372 const mdb_modinfo_t *
   2373 _mdb_init(void)
   2374 {
   2375 	return (&modinfo);
   2376 }
   2377