bin/186597: NFS mount option noinet6 ineffective for umount(8)

[Christian Weisgerber]

>Number:         186597
>Category:       bin
>Synopsis:       NFS mount option noinet6 ineffective for umount(8)
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Feb 09 18:50:00 UTC 2014
>Closed-Date:
>Last-Modified:
>Originator:     Christian Weisgerber
>Release:        FreeBSD 10.0-STABLE amd64
>Organization:
>Environment:
System: FreeBSD lorvorc.mips.inka.de 10.0-STABLE FreeBSD 10.0-STABLE #0 r261348: Sat Feb 1 14:36:57 CET 2014 naddy at lorvorc.mips.inka.de:/usr/obj/usr/src/sys/GENERIC amd64

>Description:

By default, mounting an NFS filesystem from a server that has an
AAAA record but doesn't support RPC/NFS over IPv6 causes mount(8)
to hang.  This can be avoided by specifying the "noinet6" mount
option.

However, even with "noinet6" umount(8) will hang when unmounting
the filesystem.  If you ^C umount, the filesystem has successfully
been unmounted.

A workaround is to specify the server by its IPv4 address rather
than hostname.

>How-To-Repeat:

>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: