kern/56191: ZFS tests fail on sparc64

[martin%NetBSD.org@localhost]

>Number:         56191
>Category:       kern
>Synopsis:       ZFS tests fail on sparc64
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed May 19 17:15:00 +0000 2021
>Originator:     Martin Husemann
>Release:        NetBSD 9.99.82
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD thirdstage.duskware.de 9.99.82 NetBSD 9.99.82 (MODULAR) #447: Wed May 19 17:37:49 CEST 2021 martin%thirdstage.duskware.de@localhost:/usr/src/sys/arch/sparc64/compile/MODULAR sparc64
Architecture: sparc64
Machine: sparc64
>Description:

Roughly about the time we switched to gcc 10, many ZFS tests started
failing on sparc64 - with some not very clear error message:

tc-start: 1621443124.796297, zfs_read_after_unlink
tc-se:cannot create 'mnt': operation not supported on this type of pool
tc-so:[   1.0000000] entropy: ready
tc-so:[   1.0200050] ZFS filesystem version: 5
tc-end: 1621443125.178562, zfs_read_after_unlink, failed, mount failed: Unknown error: 256


>How-To-Repeat:
Run the vfs tests on sparc64

>Fix:
n/a