illumos gate

Root cause

The problem seems to be that validate_disk() does this (unconditionally):

648    (void) snprintf(kernpath, MAXPATHLEN, "%s/platform/i86pc/kernel/unix",
649        mountpoint);
650
651    if (stat64(kernpath, &statbuf) != 0) {
652        (void) fprintf(stderr,
653            gettext("%s: %s is not a root disk or dataset\n"),
654            cmdname, arg);
655        return (1);
656    }

The validate_disk() is called from parse_fastboot_args() and few lines after the call there is platform detection implemented, but it is too late for us:

1102    /*
1103     * If BE is not specified, look for disk argument to construct
1104     * mountpoint; if BE has been specified, mountpoint has already been
1105     * constructed.
1106     */
1107    if (newarg && newarg[0] != '-' && !bename) {
1108        int tmprc;
1109
1110        if ((tmprc = validate_disk(newarg, mountpoint)) == 0) {

...

1132        }
1133    }

...

1143    /*
1144     * Look for unix argument
1145     */
1146    if (newarg && newarg[0] != '-') {
1147        bcopy(newarg, &unixfile[mplen], strlen(newarg));
1148        newarg = strtok(NULL, " ");
1149        rootlen = (newarg) ? (newarg - head) : buflen;
1150    } else if (mplen != 0) {
1151        /*
1152         * No unix argument, but mountpoint is not empty, use
1153         * /platform/i86pc/$ISADIR/kernel/unix as default.
1154         */
1155        char isa[20];
1156
1157        if (sysinfo(SI_ARCHITECTURE_64, isa, sizeof (isa)) != -1)
1158            (void) snprintf(&unixfile[mplen],
1159                sizeof (unixfile) - mplen,
1160                "/platform/i86pc/kernel/%s/unix", isa);
1161        else if (sysinfo(SI_ARCHITECTURE_32, isa, sizeof (isa)) != -1) {
1162            (void) snprintf(&unixfile[mplen],
1163                sizeof (unixfile) - mplen,
1164                "/platform/i86pc/kernel/unix");
1165        } else {
1166            (void) fprintf(stderr,
1167                gettext("%s: Unknown architecture"), cmdname);
1168            return (EINVAL);
1169        }
1170    }

Review: https://www.illumos.org/rb/r/2502/

Testing Done

Without the fix:

# beadm create new
Created successfully
# reboot -f -- rpool/ROOT/new
reboot: rpool/ROOT/new is not a root disk or dataset
# beadm destroy -fF new
#

With the fix:

# beadm create new
Created successfully
# reboot -f -- rpool/ROOT/new
Connection to localhost closed by remote host.
Connection to localhost closed.
$