Date: Tue, 28 Nov 2006 16:34:50 -0500 From: Christopher Sean Hilton <chris@vindaloo.com> To: Roland Smith <rsmith@xs4all.nl> Cc: "O. Hartmann" <ohartman@mail.zedat.fu-berlin.de>, FreeBSD Stable <freebsd-stable@freebsd.org> Subject: Amd and UFS mounts Message-ID: <1164749690.1074.33.camel@dagobah.vindaloo.com> In-Reply-To: <20061125164008.GA5008@slackbox.xs4all.nl> References: <45686A63.6030708@mail.zedat.fu-berlin.de> <20061125164008.GA5008@slackbox.xs4all.nl>
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It's dim but I seem to remember that amd had no problems mounting a UFS
volume but it would never time it out. This may be the bug that Oliver
is referring to.
This caused problems when using UFS on a USB stick since the drive would
never be dismounted so it was never safe to remove from the USB port.
I've just retested this and amd doesn't automatically time out a ufs
volume unless you ask it to by using the amq command. If I remember my
research correctly this is a feature, not a bug.
It's important to be able to get these volumes to unmount automatically.
The reason I researched this before was because I would continually
forget to unmount the usb stick before I suspended my computer. Before I
implemented this I was fscking my usb stick an average of twice a day.
After that I only had to fsck usb attached storage once every two weeks.
Although my current laptop won't suspend/resume cleanly I still find it
useful. The usb hub in the docking station triggers bugs in FreeBSD's
usb subsystem. Every once in a while the usb subsystem will hiccup.
Normally this isn't a problem but if a drive is plugged in and mounted
at the time of the hiccup then the drive won't detach properly and on
system shutdown you get a stuck buffer which causes a need for a
background fsck on the regular drives and a full fsck on the usb drive.
I worked around the UFS mounts problem by using program mounts in amd.
>From time to time I am tempted to write a "How-To" on getting amd to
work with pendrives going all the way through using fdisk, disklabel,
and newfs to put a native FreeBSD filesystem on a USB stick or portable
hard drive but I always chicken out at the point where I'm telling the
user how to modify /etc/fstab for fear that if someone slips up with vi
they end up with an unusable FreeBSD install.
In any case here's how I'm using amd with my pendrives: I've
standardized on MSDOS FAT filesystems in <device>s1 and FreeBSD
filesystem in <device>s2. Amd handles the e partition on on the FreeBSD
slice. So the first usb drive will usually be device: /dev/da0. Under my
system the MS-DOS slice on that drive will be /dev/da0s1 and can be
accessed by any user via the amd by doing:
ls -l /amd/msdos0
On a successful mount the user gets a symlink listing. The user can
unmount the command by doing:
amq -u /amd/msdos0
This will only work if there are no processes accessing the drive. If
the user forgets amd does this automatically after 30 seconds. The
utility FreeBSD partition, /amd/da0s2e is available as /amd/ufs0 and
works the same as the msdos partition.
----------------------------------------------------------------------------
***** Startup Options *****
I run amd with a conf file because on some machines I use it as a means
of nfs mounting my home directories.
$ grep amd /etc/rc.conf
## amd
amd_enable="YES" # Run amd service with $amd_flags (or NO).
amd_flags="-F /etc/amd.conf"
***** Amd Configuration options *****
Nothing really special here.
$ cat /etc/amd.conf
[ global ]
browsable_dirs = no
map_type = file
mount_type = nfs
search_path = /etc
auto_dir = /.amd
cache_duration = 30
log_file = syslog:daemon
log_options = info
print_pid = yes
pid_file = /var/run/amd.pid
restart_mounts = yes
selectors_in_defaults = no
[ /amd ]
map_name = /etc/amd.map
***** Map files *****
Here's how amd maps a directory to a filesystem.
$ cat /etc/amd.map
# $FreeBSD: src/etc/amd.map,v 1.9 2002/05/15 22:24:29 obrien Exp $
#
## /defaults type:=host;fs:=${autodir}/${rhost}/host;rhost:=${key}
## * opts:=rw,grpid,resvport,vers=3,proto=udp,nosuid,nodev
## To use:
## mkdir -p /amd /.amd /.amd/cdrom /.amd/disk0 /.amd/disk1
## chmod 755 /.amd/*
## chmod 555 /.amd /amd
##
## Hotpluggable disks: Firewire, USB, etc. All the work gets done by
## setting up the appropriate entry in /etc/fstab. Ex. My firewire
## enclosures appear as { da0, and da1 } my convention is to put the
## msdos filesystem, if any, in slice 1 and the hotpluggable FreeBSD
## filesystem, if any, in partition e of slice 2. The system expects
## that the hotpluggable freebsd filesystem will have all "autorun"
## scripts. So, the first firewire drive needs the following entries
## in /etc/fstab:
##
## /dev/da0s1 /.amd/msdos0 msdos rw,noauto 0 0
## /dev/da0s2e /.amd/ufs0 ufs rw,nosuid,nodev,noauto 0 0
msdos0 type:=program;fs:=${autodir}/${key};\
mount:="/sbin/mount mount ${fs}";\
unmount:="/sbin/umount umount ${fs}"
ufs0 type:=program;fs:=${autodir}/${key};\
mount:="/sbin/mount mount ${fs}";\
unmount:="/sbin/umount umount ${fs}"
***** Fstab entrys *****
Careful here. If you want to be really paranoid here add noexec to the mount flags.
...
/dev/acd0 /.amd/cdrom cd9660 ro,noauto 0 0
/dev/da0s1 /.amd/msdos0 msdos rw,longnames,noauto 0 0
/dev/da0s2e /.amd/ufs0 ufs rw,nosuid,nodev,noauto 0 0
...
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