Date: Tue, 13 May 1997 23:39:05 +0900 (JST) From: Takahiro Yugawa <yugawa@orleans.rim.or.jp> To: FreeBSD-gnats-submit@FreeBSD.ORG Cc: yugawa@oleo.orleans.rim.or.jp Subject: bin/3588: Memory Filesystem unmounting problem Message-ID: <199705131439.XAA04885@oleo.orleans.rim.or.jp> Resent-Message-ID: <199705131510.IAA24168@hub.freebsd.org>
next in thread | raw e-mail | index | archive | help
>Number: 3588
>Category: bin
>Synopsis: Memory Filesystem unmounting problem
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Tue May 13 08:10:01 PDT 1997
>Last-Modified:
>Originator: Takahiro Yugawa
>Organization:
personal FreeBSD user in Japan
>Release: FreeBSD 2.2.1-RELEASE i386
>Environment:
General FreeBSD environment with 'options MFS' enabled kernel.
>Description:
When unmounting mfs like '# umount /tmp',
umount process searches for host 'mfs'.
And if there is a host named 'mfs', an error will occur with
umount command.
If there isn't a host named 'mfs' but the host is configured to
use name server, umount produces unnecessary network packet.
In /usr/src/sbin/umount/umount.c, there is a function named
umountfs(). The argument to the function umountfs(), named 'name',
is a file system name (which can see at the left most column
at the output of df command).
Umountfs() searches '@' or ':' character in variable 'name' to see
if it is a NFS or not. Since file system name for mfs is
'mfs:[pid of mfs]', umountfs() thinks it is a NFS (because there is
':' in it) and then searches for host named 'mfs' with
gethostbyname() function.
>How-To-Repeat:
First, prepare a kernel with 'options MFS' enabled.
Then prepare a host named 'mfs'. The easiest way is to add
an alias 'mfs' to localhost(127.0.0.1) in /etc/hosts like,
127.0.0.1 localhost mfs
Then mount mfs with mount_mfs command like,
# mount_mfs -s 2048 /dev/wd0s2b /tmp
And, then umount mfs with umount command like,
# umount /tmp
This umount process produces message like
"Cannot MNT PRC: RPC: Program not registered."
Or, give an IP address for host 'mfs'(actually it isn't exist),
and do mounting & umounting as above produces message like
"Cannot MNT PRC: RPC: Port mapper failure - RPC: Unable to send."
In any cases, mfs will actually umounted, though.
>Fix:
I think there are several ways to fix the problem.
One of them is to change file system name for mfs to something
like 'mfs![pid of mfs]', and not include a character '@' or ':'
in it.
I didn't do this because I wonder there may be some side effects.
Another way and my solution is to change
/usr/src/sbin/umount/umount.c like this.
*** umount.c.orig Tue May 13 23:31:17 1997
--- umount.c Tue May 13 23:31:40 1997
***************
*** 219,225 ****
if (!selected(type))
return (0);
! if ((delimp = strchr(name, '@')) != NULL) {
hostp = delimp + 1;
*delimp = '\0';
hp = gethostbyname(hostp);
--- 219,227 ----
if (!selected(type))
return (0);
! if (strstr( name, "mfs:" ) == name && isdigit(*(name+4))) {
! hp = NULL;
! } else if ((delimp = strchr(name, '@')) != NULL) {
hostp = delimp + 1;
*delimp = '\0';
hp = gethostbyname(hostp);
>Audit-Trail:
>Unformatted:
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199705131439.XAA04885>