Illumos #3498 panic in arc_read()
[zfs.git] / cmd / zdb / zdb.c
index c6e219d..936974b 100644 (file)
  *
  * CDDL HEADER END
  */
+
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012 by Delphix. All rights reserved.
  */
 
 #include <stdio.h>
 #include <sys/zfs_fuid.h>
 #include <sys/arc.h>
 #include <sys/ddt.h>
+#include <sys/zfeature.h>
 #undef ZFS_MAXNAMELEN
-#undef verify
 #include <libzfs.h>
 
-#define        ZDB_COMPRESS_NAME(idx) ((idx) < ZIO_COMPRESS_FUNCTIONS ? \
-    zio_compress_table[(idx)].ci_name : "UNKNOWN")
-#define        ZDB_CHECKSUM_NAME(idx) ((idx) < ZIO_CHECKSUM_FUNCTIONS ? \
-    zio_checksum_table[(idx)].ci_name : "UNKNOWN")
-#define        ZDB_OT_NAME(idx) ((idx) < DMU_OT_NUMTYPES ? \
-    dmu_ot[(idx)].ot_name : "UNKNOWN")
-#define        ZDB_OT_TYPE(idx) ((idx) < DMU_OT_NUMTYPES ? (idx) : DMU_OT_NUMTYPES)
+#define        ZDB_COMPRESS_NAME(idx) ((idx) < ZIO_COMPRESS_FUNCTIONS ?        \
+       zio_compress_table[(idx)].ci_name : "UNKNOWN")
+#define        ZDB_CHECKSUM_NAME(idx) ((idx) < ZIO_CHECKSUM_FUNCTIONS ?        \
+       zio_checksum_table[(idx)].ci_name : "UNKNOWN")
+#define        ZDB_OT_NAME(idx) ((idx) < DMU_OT_NUMTYPES ?     \
+       dmu_ot[(idx)].ot_name : DMU_OT_IS_VALID(idx) ?  \
+       dmu_ot_byteswap[DMU_OT_BYTESWAP(idx)].ob_name : "UNKNOWN")
+#define        ZDB_OT_TYPE(idx) ((idx) < DMU_OT_NUMTYPES ? (idx) :             \
+       (((idx) == DMU_OTN_ZAP_DATA || (idx) == DMU_OTN_ZAP_METADATA) ? \
+       DMU_OT_ZAP_OTHER : DMU_OT_NUMTYPES))
 
 #ifndef lint
 extern int zfs_recover;
@@ -81,13 +86,14 @@ extern void dump_intent_log(zilog_t *);
 uint64_t *zopt_object = NULL;
 int zopt_objects = 0;
 libzfs_handle_t *g_zfs;
+uint64_t max_inflight = 200;
 
 /*
  * These libumem hooks provide a reasonable set of defaults for the allocator's
  * debugging facilities.
  */
 const char *
-_umem_debug_init()
+_umem_debug_init(void)
 {
        return ("default,verbose"); /* $UMEM_DEBUG setting */
 }
@@ -102,13 +108,17 @@ static void
 usage(void)
 {
        (void) fprintf(stderr,
-           "Usage: %s [-CumdibcsDvhL] poolname [object...]\n"
-           "       %s [-div] dataset [object...]\n"
-           "       %s -m [-L] poolname [vdev [metaslab...]]\n"
-           "       %s -R poolname vdev:offset:size[:flags]\n"
-           "       %s -S poolname\n"
-           "       %s -l [-u] device\n"
-           "       %s -C\n\n",
+           "Usage: %s [-CumdibcsDvhLXFPA] [-t txg] [-e [-p path...]] "
+           "[-U config] [-M inflight I/Os] poolname [object...]\n"
+           "       %s [-divPA] [-e -p path...] [-U config] dataset "
+           "[object...]\n"
+           "       %s -m [-LXFPA] [-t txg] [-e [-p path...]] [-U config] "
+           "poolname [vdev [metaslab...]]\n"
+           "       %s -R [-A] [-e [-p path...]] poolname "
+           "vdev:offset:size[:flags]\n"
+           "       %s -S [-PA] [-e [-p path...]] [-U config] poolname\n"
+           "       %s -l [-uA] device\n"
+           "       %s -C [-A] [-U config]\n\n",
            cmdname, cmdname, cmdname, cmdname, cmdname, cmdname, cmdname);
 
        (void) fprintf(stderr, "    Dataset name must include at least one "
@@ -150,9 +160,11 @@ usage(void)
            "has altroot/not in a cachefile\n");
        (void) fprintf(stderr, "        -p <path> -- use one or more with "
            "-e to specify path to vdev dir\n");
-       (void) fprintf(stderr, "        -P print numbers parsable\n");
+       (void) fprintf(stderr, "        -P print numbers in parseable form\n");
        (void) fprintf(stderr, "        -t <txg> -- highest txg to use when "
            "searching for uberblocks\n");
+       (void) fprintf(stderr, "        -M <number of inflight I/Os> -- "
+           "specify the maximum number of checksumming I/Os [default is 200]\n");
        (void) fprintf(stderr, "Specify an option more than once (e.g. -bb) "
            "to make only that option verbose\n");
        (void) fprintf(stderr, "Default is to dump everything non-verbosely\n");
@@ -536,7 +548,7 @@ static void
 dump_metaslab_stats(metaslab_t *msp)
 {
        char maxbuf[32];
-       space_map_t *sm = &msp->ms_map;
+       space_map_t *sm = msp->ms_map;
        avl_tree_t *t = sm->sm_pp_root;
        int free_pct = sm->sm_space * 100 / sm->sm_size;
 
@@ -552,7 +564,7 @@ dump_metaslab(metaslab_t *msp)
 {
        vdev_t *vd = msp->ms_group->mg_vd;
        spa_t *spa = vd->vdev_spa;
-       space_map_t *sm = &msp->ms_map;
+       space_map_t *sm = msp->ms_map;
        space_map_obj_t *smo = &msp->ms_smo;
        char freebuf[32];
 
@@ -645,8 +657,9 @@ dump_dde(const ddt_t *ddt, const ddt_entry_t *dde, uint64_t index)
        char *types[4] = { "ditto", "single", "double", "triple" };
        char blkbuf[BP_SPRINTF_LEN];
        blkptr_t blk;
+       int p;
 
-       for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
+       for (p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
                if (ddp->ddp_phys_birth == 0)
                        continue;
                ddt_bp_create(ddt->ddt_checksum, ddk, ddp, &blk);
@@ -695,7 +708,9 @@ dump_ddt(ddt_t *ddt, enum ddt_type type, enum ddt_class class)
                return;
        ASSERT(error == 0);
 
-       if ((count = ddt_object_count(ddt, type, class)) == 0)
+       error = ddt_object_count(ddt, type, class, &count);
+       ASSERT(error == 0);
+       if (count == 0)
                return;
 
        dspace = doi.doi_physical_blocks_512 << 9;
@@ -733,13 +748,19 @@ dump_ddt(ddt_t *ddt, enum ddt_type type, enum ddt_class class)
 static void
 dump_all_ddts(spa_t *spa)
 {
-       ddt_histogram_t ddh_total = { 0 };
-       ddt_stat_t dds_total = { 0 };
+       ddt_histogram_t ddh_total;
+       ddt_stat_t dds_total;
+       enum zio_checksum c;
+       enum ddt_type type;
+       enum ddt_class class;
+
+       bzero(&ddh_total, sizeof (ddt_histogram_t));
+       bzero(&dds_total, sizeof (ddt_stat_t));
 
-       for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
+       for (c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
                ddt_t *ddt = spa->spa_ddt[c];
-               for (enum ddt_type type = 0; type < DDT_TYPES; type++) {
-                       for (enum ddt_class class = 0; class < DDT_CLASSES;
+               for (type = 0; type < DDT_TYPES; type++) {
+                       for (class = 0; class < DDT_CLASSES;
                            class++) {
                                dump_ddt(ddt, type, class);
                        }
@@ -783,6 +804,7 @@ dump_dtl(vdev_t *vd, int indent)
        boolean_t required;
        char *name[DTL_TYPES] = { "missing", "partial", "scrub", "outage" };
        char prefix[256];
+       int c, t;
 
        spa_vdev_state_enter(spa, SCL_NONE);
        required = vdev_dtl_required(vd);
@@ -796,7 +818,7 @@ dump_dtl(vdev_t *vd, int indent)
            vd->vdev_parent ? vd->vdev_ops->vdev_op_type : spa_name(spa),
            required ? "DTL-required" : "DTL-expendable");
 
-       for (int t = 0; t < DTL_TYPES; t++) {
+       for (t = 0; t < DTL_TYPES; t++) {
                space_map_t *sm = &vd->vdev_dtl[t];
                if (sm->sm_space == 0)
                        continue;
@@ -810,7 +832,7 @@ dump_dtl(vdev_t *vd, int indent)
                            &vd->vdev_dtl_smo, sm);
        }
 
-       for (int c = 0; c < vd->vdev_children; c++)
+       for (c = 0; c < vd->vdev_children; c++)
                dump_dtl(vd->vdev_child[c], indent + 4);
 }
 
@@ -826,6 +848,7 @@ dump_history(spa_t *spa)
        struct tm t;
        char tbuf[30];
        char internalstr[MAXPATHLEN];
+       int i;
 
        do {
                len = sizeof (buf);
@@ -843,7 +866,7 @@ dump_history(spa_t *spa)
        } while (len != 0);
 
        (void) printf("\nHistory:\n");
-       for (int i = 0; i < num; i++) {
+       for (i = 0; i < num; i++) {
                uint64_t time, txg, ievent;
                char *cmd, *intstr;
 
@@ -865,8 +888,8 @@ dump_history(spa_t *spa)
                        (void) snprintf(internalstr,
                            sizeof (internalstr),
                            "[internal %s txg:%lld] %s",
-                           zfs_history_event_names[ievent], txg,
-                           intstr);
+                           zfs_history_event_names[ievent],
+                           (longlong_t)txg, intstr);
                        cmd = internalstr;
                }
                tsec = time;
@@ -904,6 +927,7 @@ sprintf_blkptr_compact(char *blkbuf, const blkptr_t *bp)
 {
        const dva_t *dva = bp->blk_dva;
        int ndvas = dump_opt['d'] > 5 ? BP_GET_NDVAS(bp) : 1;
+       int i;
 
        if (dump_opt['b'] >= 5) {
                sprintf_blkptr(blkbuf, bp);
@@ -912,7 +936,7 @@ sprintf_blkptr_compact(char *blkbuf, const blkptr_t *bp)
 
        blkbuf[0] = '\0';
 
-       for (int i = 0; i < ndvas; i++)
+       for (i = 0; i < ndvas; i++)
                (void) sprintf(blkbuf + strlen(blkbuf), "%llu:%llx:%llx ",
                    (u_longlong_t)DVA_GET_VDEV(&dva[i]),
                    (u_longlong_t)DVA_GET_OFFSET(&dva[i]),
@@ -972,7 +996,7 @@ visit_indirect(spa_t *spa, const dnode_phys_t *dnp,
                arc_buf_t *buf;
                uint64_t fill = 0;
 
-               err = arc_read_nolock(NULL, spa, bp, arc_getbuf_func, &buf,
+               err = arc_read(NULL, spa, bp, arc_getbuf_func, &buf,
                    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
                if (err)
                        return (err);
@@ -1085,7 +1109,7 @@ dump_dsl_dataset(objset_t *os, uint64_t object, void *data, size_t size)
 
        ASSERT(size == sizeof (*ds));
        crtime = ds->ds_creation_time;
-       zdb_nicenum(ds->ds_used_bytes, used);
+       zdb_nicenum(ds->ds_referenced_bytes, used);
        zdb_nicenum(ds->ds_compressed_bytes, compressed);
        zdb_nicenum(ds->ds_uncompressed_bytes, uncompressed);
        zdb_nicenum(ds->ds_unique_bytes, unique);
@@ -1129,6 +1153,44 @@ dump_dsl_dataset(objset_t *os, uint64_t object, void *data, size_t size)
 
 /* ARGSUSED */
 static int
+dump_bptree_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
+{
+       char blkbuf[BP_SPRINTF_LEN];
+
+       if (bp->blk_birth != 0) {
+               sprintf_blkptr(blkbuf, bp);
+               (void) printf("\t%s\n", blkbuf);
+       }
+       return (0);
+}
+
+static void
+dump_bptree(objset_t *os, uint64_t obj, char *name)
+{
+       char bytes[32];
+       bptree_phys_t *bt;
+       dmu_buf_t *db;
+
+       if (dump_opt['d'] < 3)
+               return;
+
+       VERIFY3U(0, ==, dmu_bonus_hold(os, obj, FTAG, &db));
+       bt = db->db_data;
+       zdb_nicenum(bt->bt_bytes, bytes);
+       (void) printf("\n    %s: %llu datasets, %s\n",
+           name, (unsigned long long)(bt->bt_end - bt->bt_begin), bytes);
+       dmu_buf_rele(db, FTAG);
+
+       if (dump_opt['d'] < 5)
+               return;
+
+       (void) printf("\n");
+
+       (void) bptree_iterate(os, obj, B_FALSE, dump_bptree_cb, NULL, NULL);
+}
+
+/* ARGSUSED */
+static int
 dump_bpobj_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
 {
        char blkbuf[BP_SPRINTF_LEN];
@@ -1211,7 +1273,7 @@ static boolean_t sa_loaded;
 sa_attr_type_t *sa_attr_table;
 
 static void
-fuid_table_destroy()
+fuid_table_destroy(void)
 {
        if (fuid_table_loaded) {
                zfs_fuid_table_destroy(&idx_tree, &domain_tree);
@@ -1658,7 +1720,7 @@ dump_uberblock(uberblock_t *ub, const char *header, const char *footer)
 {
        time_t timestamp = ub->ub_timestamp;
 
-       (void) printf(header ? header : "");
+       (void) printf("%s", header ? header : "");
        (void) printf("\tmagic = %016llx\n", (u_longlong_t)ub->ub_magic);
        (void) printf("\tversion = %llu\n", (u_longlong_t)ub->ub_version);
        (void) printf("\ttxg = %llu\n", (u_longlong_t)ub->ub_txg);
@@ -1670,7 +1732,7 @@ dump_uberblock(uberblock_t *ub, const char *header, const char *footer)
                sprintf_blkptr(blkbuf, &ub->ub_rootbp);
                (void) printf("\trootbp = %s\n", blkbuf);
        }
-       (void) printf(footer ? footer : "");
+       (void) printf("%s", footer ? footer : "");
 }
 
 static void
@@ -1751,11 +1813,12 @@ dump_label_uberblocks(vdev_label_t *lbl, uint64_t ashift)
        vdev_t vd;
        vdev_t *vdp = &vd;
        char header[ZDB_MAX_UB_HEADER_SIZE];
+       int i;
 
        vd.vdev_ashift = ashift;
        vdp->vdev_top = vdp;
 
-       for (int i = 0; i < VDEV_UBERBLOCK_COUNT(vdp); i++) {
+       for (i = 0; i < VDEV_UBERBLOCK_COUNT(vdp); i++) {
                uint64_t uoff = VDEV_UBERBLOCK_OFFSET(vdp, i);
                uberblock_t *ub = (void *)((char *)lbl + uoff);
 
@@ -1777,6 +1840,7 @@ dump_label(const char *dev)
        struct stat64 statbuf;
        uint64_t psize, ashift;
        int len = strlen(dev) + 1;
+       int l;
 
        if (strncmp(dev, "/dev/dsk/", 9) == 0) {
                len++;
@@ -1792,7 +1856,7 @@ dump_label(const char *dev)
                exit(1);
        }
 
-       if (fstat64(fd, &statbuf) != 0) {
+       if (fstat64_blk(fd, &statbuf) != 0) {
                (void) printf("failed to stat '%s': %s\n", path,
                    strerror(errno));
                free(path);
@@ -1800,18 +1864,10 @@ dump_label(const char *dev)
                exit(1);
        }
 
-       if (S_ISBLK(statbuf.st_mode)) {
-               (void) printf("cannot use '%s': character device required\n",
-                   path);
-               free(path);
-               (void) close(fd);
-               exit(1);
-       }
-
        psize = statbuf.st_size;
        psize = P2ALIGN(psize, (uint64_t)sizeof (vdev_label_t));
 
-       for (int l = 0; l < VDEV_LABELS; l++) {
+       for (l = 0; l < VDEV_LABELS; l++) {
                nvlist_t *config = NULL;
 
                (void) printf("--------------------------------------------\n");
@@ -1880,11 +1936,13 @@ typedef struct zdb_blkstats {
  */
 #define        ZDB_OT_DEFERRED (DMU_OT_NUMTYPES + 0)
 #define        ZDB_OT_DITTO    (DMU_OT_NUMTYPES + 1)
-#define        ZDB_OT_TOTAL    (DMU_OT_NUMTYPES + 2)
+#define        ZDB_OT_OTHER    (DMU_OT_NUMTYPES + 2)
+#define        ZDB_OT_TOTAL    (DMU_OT_NUMTYPES + 3)
 
 static char *zdb_ot_extname[] = {
        "deferred free",
        "dedup ditto",
+       "other",
        "Total",
 };
 
@@ -1905,13 +1963,14 @@ zdb_count_block(zdb_cb_t *zcb, zilog_t *zilog, const blkptr_t *bp,
     dmu_object_type_t type)
 {
        uint64_t refcnt = 0;
+       int i;
 
        ASSERT(type < ZDB_OT_TOTAL);
 
        if (zilog && zil_bp_tree_add(zilog, bp) != 0)
                return;
 
-       for (int i = 0; i < 4; i++) {
+       for (i = 0; i < 4; i++) {
                int l = (i < 2) ? BP_GET_LEVEL(bp) : ZB_TOTAL;
                int t = (i & 1) ? type : ZDB_OT_TOTAL;
                zdb_blkstats_t *zb = &zcb->zcb_type[l][t];
@@ -1950,9 +2009,47 @@ zdb_count_block(zdb_cb_t *zcb, zilog_t *zilog, const blkptr_t *bp,
            bp, NULL, NULL, ZIO_FLAG_CANFAIL)), ==, 0);
 }
 
-/* ARGSUSED */
+static void
+zdb_blkptr_done(zio_t *zio)
+{
+       spa_t *spa = zio->io_spa;
+       blkptr_t *bp = zio->io_bp;
+       int ioerr = zio->io_error;
+       zdb_cb_t *zcb = zio->io_private;
+       zbookmark_t *zb = &zio->io_bookmark;
+
+       zio_data_buf_free(zio->io_data, zio->io_size);
+
+       mutex_enter(&spa->spa_scrub_lock);
+       spa->spa_scrub_inflight--;
+       cv_broadcast(&spa->spa_scrub_io_cv);
+
+       if (ioerr && !(zio->io_flags & ZIO_FLAG_SPECULATIVE)) {
+               char blkbuf[BP_SPRINTF_LEN];
+
+               zcb->zcb_haderrors = 1;
+               zcb->zcb_errors[ioerr]++;
+
+               if (dump_opt['b'] >= 2)
+                       sprintf_blkptr(blkbuf, bp);
+               else
+                       blkbuf[0] = '\0';
+
+               (void) printf("zdb_blkptr_cb: "
+                   "Got error %d reading "
+                   "<%llu, %llu, %lld, %llx> %s -- skipping\n",
+                   ioerr,
+                   (u_longlong_t)zb->zb_objset,
+                   (u_longlong_t)zb->zb_object,
+                   (u_longlong_t)zb->zb_level,
+                   (u_longlong_t)zb->zb_blkid,
+                   blkbuf);
+       }
+       mutex_exit(&spa->spa_scrub_lock);
+}
+
 static int
-zdb_blkptr_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp, arc_buf_t *pbuf,
+zdb_blkptr_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
     const zbookmark_t *zb, const dnode_phys_t *dnp, void *arg)
 {
        zdb_cb_t *zcb = arg;
@@ -1965,44 +2062,29 @@ zdb_blkptr_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp, arc_buf_t *pbuf,
 
        type = BP_GET_TYPE(bp);
 
-       zdb_count_block(zcb, zilog, bp, type);
+       zdb_count_block(zcb, zilog, bp,
+           (type & DMU_OT_NEWTYPE) ? ZDB_OT_OTHER : type);
 
-       is_metadata = (BP_GET_LEVEL(bp) != 0 || dmu_ot[type].ot_metadata);
+       is_metadata = (BP_GET_LEVEL(bp) != 0 || DMU_OT_IS_METADATA(type));
 
        if (dump_opt['c'] > 1 || (dump_opt['c'] && is_metadata)) {
-               int ioerr;
                size_t size = BP_GET_PSIZE(bp);
-               void *data = malloc(size);
+               void *data = zio_data_buf_alloc(size);
                int flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCRUB | ZIO_FLAG_RAW;
 
                /* If it's an intent log block, failure is expected. */
                if (zb->zb_level == ZB_ZIL_LEVEL)
                        flags |= ZIO_FLAG_SPECULATIVE;
 
-               ioerr = zio_wait(zio_read(NULL, spa, bp, data, size,
-                   NULL, NULL, ZIO_PRIORITY_ASYNC_READ, flags, zb));
+               mutex_enter(&spa->spa_scrub_lock);
+               while (spa->spa_scrub_inflight > max_inflight)
+                       cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
+               spa->spa_scrub_inflight++;
+               mutex_exit(&spa->spa_scrub_lock);
 
-               free(data);
+               zio_nowait(zio_read(NULL, spa, bp, data, size,
+                   zdb_blkptr_done, zcb, ZIO_PRIORITY_ASYNC_READ, flags, zb));
 
-               if (ioerr && !(flags & ZIO_FLAG_SPECULATIVE)) {
-                       zcb->zcb_haderrors = 1;
-                       zcb->zcb_errors[ioerr]++;
-
-                       if (dump_opt['b'] >= 2)
-                               sprintf_blkptr(blkbuf, bp);
-                       else
-                               blkbuf[0] = '\0';
-
-                       (void) printf("zdb_blkptr_cb: "
-                           "Got error %d reading "
-                           "<%llu, %llu, %lld, %llx> %s -- skipping\n",
-                           ioerr,
-                           (u_longlong_t)zb->zb_objset,
-                           (u_longlong_t)zb->zb_object,
-                           (u_longlong_t)zb->zb_level,
-                           (u_longlong_t)zb->zb_blkid,
-                           blkbuf);
-               }
        }
 
        zcb->zcb_readfails = 0;
@@ -2063,6 +2145,7 @@ zdb_ddt_leak_init(spa_t *spa, zdb_cb_t *zcb)
        ddt_bookmark_t ddb = { 0 };
        ddt_entry_t dde;
        int error;
+       int p;
 
        while ((error = ddt_walk(spa, &ddb, &dde)) == 0) {
                blkptr_t blk;
@@ -2073,7 +2156,7 @@ zdb_ddt_leak_init(spa_t *spa, zdb_cb_t *zcb)
 
                ASSERT(ddt_phys_total_refcnt(&dde) > 1);
 
-               for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
+               for (p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
                        if (ddp->ddp_phys_birth == 0)
                                continue;
                        ddt_bp_create(ddb.ddb_checksum,
@@ -2101,19 +2184,20 @@ static void
 zdb_leak_init(spa_t *spa, zdb_cb_t *zcb)
 {
        zcb->zcb_spa = spa;
+       int c, m;
 
        if (!dump_opt['L']) {
                vdev_t *rvd = spa->spa_root_vdev;
-               for (int c = 0; c < rvd->vdev_children; c++) {
+               for (c = 0; c < rvd->vdev_children; c++) {
                        vdev_t *vd = rvd->vdev_child[c];
-                       for (int m = 0; m < vd->vdev_ms_count; m++) {
+                       for (m = 0; m < vd->vdev_ms_count; m++) {
                                metaslab_t *msp = vd->vdev_ms[m];
                                mutex_enter(&msp->ms_lock);
-                               space_map_unload(&msp->ms_map);
-                               VERIFY(space_map_load(&msp->ms_map,
+                               space_map_unload(msp->ms_map);
+                               VERIFY(space_map_load(msp->ms_map,
                                    &zdb_space_map_ops, SM_ALLOC, &msp->ms_smo,
                                    spa->spa_meta_objset) == 0);
-                               msp->ms_map.sm_ppd = vd;
+                               msp->ms_map->sm_ppd = vd;
                                mutex_exit(&msp->ms_lock);
                        }
                }
@@ -2129,14 +2213,16 @@ zdb_leak_init(spa_t *spa, zdb_cb_t *zcb)
 static void
 zdb_leak_fini(spa_t *spa)
 {
+       int c, m;
+
        if (!dump_opt['L']) {
                vdev_t *rvd = spa->spa_root_vdev;
-               for (int c = 0; c < rvd->vdev_children; c++) {
+               for (c = 0; c < rvd->vdev_children; c++) {
                        vdev_t *vd = rvd->vdev_child[c];
-                       for (int m = 0; m < vd->vdev_ms_count; m++) {
+                       for (m = 0; m < vd->vdev_ms_count; m++) {
                                metaslab_t *msp = vd->vdev_ms[m];
                                mutex_enter(&msp->ms_lock);
-                               space_map_unload(&msp->ms_map);
+                               space_map_unload(msp->ms_map);
                                mutex_exit(&msp->ms_lock);
                        }
                }
@@ -2162,11 +2248,12 @@ count_block_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
 static int
 dump_block_stats(spa_t *spa)
 {
-       zdb_cb_t zcb = { 0 };
+       zdb_cb_t zcb;
        zdb_blkstats_t *zb, *tzb;
        uint64_t norm_alloc, norm_space, total_alloc, total_found;
        int flags = TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA | TRAVERSE_HARD;
        int leaks = 0;
+       int e;
 
        (void) printf("\nTraversing all blocks %s%s%s%s%s...\n",
            (dump_opt['c'] || !dump_opt['L']) ? "to verify " : "",
@@ -2183,6 +2270,7 @@ dump_block_stats(spa_t *spa)
         * it's not part of any space map) is a double allocation,
         * reference to a freed block, or an unclaimed log block.
         */
+       bzero(&zcb, sizeof(zdb_cb_t));
        zdb_leak_init(spa, &zcb);
 
        /*
@@ -2192,16 +2280,34 @@ dump_block_stats(spa_t *spa)
            count_block_cb, &zcb, NULL);
        (void) bpobj_iterate_nofree(&spa->spa_dsl_pool->dp_free_bpobj,
            count_block_cb, &zcb, NULL);
+       if (spa_feature_is_active(spa,
+           &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY])) {
+               VERIFY3U(0, ==, bptree_iterate(spa->spa_meta_objset,
+                   spa->spa_dsl_pool->dp_bptree_obj, B_FALSE, count_block_cb,
+                   &zcb, NULL));
+       }
 
        if (dump_opt['c'] > 1)
                flags |= TRAVERSE_PREFETCH_DATA;
 
        zcb.zcb_haderrors |= traverse_pool(spa, 0, flags, zdb_blkptr_cb, &zcb);
 
+       /*
+        * If we've traversed the data blocks then we need to wait for those
+        * I/Os to complete. We leverage "The Godfather" zio to wait on
+        * all async I/Os to complete.
+        */
+       if (dump_opt['c']) {
+               (void) zio_wait(spa->spa_async_zio_root);
+               spa->spa_async_zio_root = zio_root(spa, NULL, NULL,
+                   ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE |
+                   ZIO_FLAG_GODFATHER);
+       }
+
        if (zcb.zcb_haderrors) {
                (void) printf("\nError counts:\n\n");
                (void) printf("\t%5s  %s\n", "errno", "count");
-               for (int e = 0; e < 256; e++) {
+               for (e = 0; e < 256; e++) {
                        if (zcb.zcb_errors[e] != 0) {
                                (void) printf("\t%5d  %llu\n",
                                    e, (u_longlong_t)zcb.zcb_errors[e]);
@@ -2350,7 +2456,7 @@ typedef struct zdb_ddt_entry {
 /* ARGSUSED */
 static int
 zdb_ddt_add_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
-    arc_buf_t *pbuf, const zbookmark_t *zb, const dnode_phys_t *dnp, void *arg)
+    const zbookmark_t *zb, const dnode_phys_t *dnp, void *arg)
 {
        avl_tree_t *t = arg;
        avl_index_t where;
@@ -2368,7 +2474,7 @@ zdb_ddt_add_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
        }
 
        if (BP_IS_HOLE(bp) || BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_OFF ||
-           BP_GET_LEVEL(bp) > 0 || dmu_ot[BP_GET_TYPE(bp)].ot_metadata)
+           BP_GET_LEVEL(bp) > 0 || DMU_OT_IS_METADATA(BP_GET_TYPE(bp)))
                return (0);
 
        ddt_key_fill(&zdde_search.zdde_key, bp);
@@ -2395,8 +2501,11 @@ dump_simulated_ddt(spa_t *spa)
        avl_tree_t t;
        void *cookie = NULL;
        zdb_ddt_entry_t *zdde;
-       ddt_histogram_t ddh_total = { 0 };
-       ddt_stat_t dds_total = { 0 };
+       ddt_histogram_t ddh_total;
+       ddt_stat_t dds_total;
+
+       bzero(&ddh_total, sizeof (ddt_histogram_t));
+       bzero(&dds_total, sizeof (ddt_stat_t));
 
        avl_create(&t, ddt_entry_compare,
            sizeof (zdb_ddt_entry_t), offsetof(zdb_ddt_entry_t, zdde_node));
@@ -2473,7 +2582,14 @@ dump_zpool(spa_t *spa)
                        dump_bpobj(&spa->spa_deferred_bpobj, "Deferred frees");
                        if (spa_version(spa) >= SPA_VERSION_DEADLISTS) {
                                dump_bpobj(&spa->spa_dsl_pool->dp_free_bpobj,
-                                   "Pool frees");
+                                   "Pool snapshot frees");
+                       }
+
+                       if (spa_feature_is_active(spa,
+                           &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY])) {
+                               dump_bptree(spa->spa_meta_objset,
+                                   spa->spa_dsl_pool->dp_bptree_obj,
+                                   "Pool dataset frees");
                        }
                        dump_dtl(spa->spa_root_vdev, 0);
                }
@@ -2536,7 +2652,7 @@ zdb_dump_block_raw(void *buf, uint64_t size, int flags)
 {
        if (flags & ZDB_FLAG_BSWAP)
                byteswap_uint64_array(buf, size);
-       (void) write(1, buf, size);
+       VERIFY(write(fileno(stdout), buf, size) == size);
 }
 
 static void
@@ -2866,7 +2982,7 @@ find_zpool(char **target, nvlist_t **configp, int dirc, char **dirv)
        nvlist_t *match = NULL;
        char *name = NULL;
        char *sepp = NULL;
-       char sep;
+       char sep = 0;
        int count = 0;
        importargs_t args = { 0 };
 
@@ -2942,13 +3058,23 @@ main(int argc, char **argv)
        nvlist_t *policy = NULL;
        uint64_t max_txg = UINT64_MAX;
        int rewind = ZPOOL_NEVER_REWIND;
+       char *spa_config_path_env;
 
        (void) setrlimit(RLIMIT_NOFILE, &rl);
        (void) enable_extended_FILE_stdio(-1, -1);
 
        dprintf_setup(&argc, argv);
 
-       while ((c = getopt(argc, argv, "bcdhilmsuCDRSAFLXevp:t:U:P")) != -1) {
+       /*
+        * If there is an environment variable SPA_CONFIG_PATH it overrides
+        * default spa_config_path setting. If -U flag is specified it will
+        * override this environment variable settings once again.
+        */
+       spa_config_path_env = getenv("SPA_CONFIG_PATH");
+       if (spa_config_path_env != NULL)
+               spa_config_path = spa_config_path_env;
+
+       while ((c = getopt(argc, argv, "bcdhilmM:suCDRSAFLXevp:t:U:P")) != -1) {
                switch (c) {
                case 'b':
                case 'c':
@@ -2977,6 +3103,15 @@ main(int argc, char **argv)
                case 'v':
                        verbose++;
                        break;
+               case 'M':
+                       max_inflight = strtoull(optarg, NULL, 0);
+                       if (max_inflight == 0) {
+                               (void) fprintf(stderr, "maximum number "
+                                   "of inflight I/Os must be greater "
+                                   "than 0\n");
+                               usage();
+                       }
+                       break;
                case 'p':
                        if (searchdirs == NULL) {
                                searchdirs = umem_alloc(sizeof (char *),
@@ -3015,8 +3150,8 @@ main(int argc, char **argv)
        }
 
        kernel_init(FREAD);
-       g_zfs = libzfs_init();
-       ASSERT(g_zfs != NULL);
+       if ((g_zfs = libzfs_init()) == NULL)
+               return (1);
 
        if (dump_all)
                verbose = MAX(verbose, 1);
@@ -3131,7 +3266,13 @@ main(int argc, char **argv)
                                            argv[i], strerror(errno));
                        }
                }
-               (os != NULL) ? dump_dir(os) : dump_zpool(spa);
+               if (os != NULL) {
+                       dump_dir(os);
+               } else if (zopt_objects > 0 && !dump_opt['m']) {
+                       dump_dir(spa->spa_meta_objset);
+               } else {
+                       dump_zpool(spa);
+               }
        } else {
                flagbits['b'] = ZDB_FLAG_PRINT_BLKPTR;
                flagbits['c'] = ZDB_FLAG_CHECKSUM;