USB storage howto

Contents

  1. Intro
  2. Requirements
  3. Installation
    1. Modules for USB 1.1
    2. Modules for USB 2.0
    3. Modules for storage
    4. Clean up
  4. Configuration
    1. Usage as a storage device to extend storage
    2. How do I boot from the USB device (prep)
    3. Boot Configuration - (White Russian)
    4. Boot Configuration (Kamikaze)
    5. Installing and using IPKG packages in mount point other than root
  5. Links

1. Intro

It's useful to extend the storage capacity of your USB enabled Wrt router f. e. making a central file server. This can easily be done with connecting USB storage devices (like a USB stick or a external USB harddisc) to the USB port on your router.

2. Requirements

NOTE: Devices supporting USB v2.0

3. Installation

TIP: Some routers are USB 1.1 and 2.0 compatible. To use both devices with both versions install the modules for USB 1.1 and 2.0.

3.1. Modules for USB 1.1

For USB 1.1, try installing the UHCI drivers first: 

ipkg install kmod-usb-uhci
insmod usbcore
insmod uhci

If you see the message: 

insmod: init_module: uhci: No such device

then your hardware does not have a UHCI compliant device, so you might as well remove the package: 

ipkg remove kmod-usb-uhci

TIP: Most USB chips have UHCI controllers. If you received a "No such device" error, then try installing the kmod-usb-ohci package instead. The BCM4710 and BCM4712 based routers require kmod-usb-ohci: 

ipkg install kmod-usb-ohci
insmod usb-ohci

If you see the message: 

insmod: init_module: usb-ohci: No such device

then your hardware does not have a OHCI compliant device, so you might as well remove the package: 

ipkg remove kmod-usb-ohci

3.2. Modules for USB 2.0

This package includes the modules for USB 2.0.

NOTE: USB 2.0 support in White Russian is broken. There are some threads in the forum and some tickets as well if you like to read about what happens. (Im using WR 0.9 on an ASUS WL-500g Premium and USB 2.0 works just fine) 

ipkg install kmod-usb2
insmod ehci-hcd

If you see messages like this: 

insmod: unresolved symbol usb_calc_bus_time

try loading usbcore and then try ehci-hcd again: 

insmod usbcore
insmod ehci-hcd

3.3. Modules for storage

To add storage support finally install 

ipkg install kmod-usb-storage
insmod scsi_mod
insmod sd_mod
insmod usb-storage

3.4. Clean up

TIP: The max_scsi_luns=8 bit is needed for multi-card readers and should be added to the end of the scsi_mod line in the /etc/modules.d/60-usb-storage file.

OpenWrt uses /etc/modules.d directory to load the modules automatically on the next reboot. So reboot the router with 

reboot

Now check if OpenWrt sees your USB device (of course inserting it into your Wrt router). If it's correct you should see similar messages as on the dmesg dump below. 

dmesg


usb.c: registered new driver usbdevfs
usb.c: registered new driver hub
uhci.c: USB Universal Host Controller Interface driver v1.1
PCI: Enabling device 01:02.0 (0000 -> 0001)
uhci.c: USB UHCI at I/O 0x100, IRQ 2
usb.c: new USB bus registered, assigned bus number 1
hub.c: USB hub found
hub.c: 2 ports detected
PCI: Enabling device 01:02.1 (0000 -> 0001)
uhci.c: USB UHCI at I/O 0x120, IRQ 2
usb.c: new USB bus registered, assigned bus number 2
hub.c: USB hub found
hub.c: 2 ports detected
hub.c: new USB device 01:02.0-2, assigned address 2
usb.c: USB device 2 (vend/prod 0xd7d/0x100) is not claimed by any active driver.
Initializing USB Mass Storage driver...
usb.c: registered new driver usb-storage
scsi0 : SCSI emulation for USB Mass Storage devices
  Vendor: Apacer    Model: Drive             Rev: 1.05
  Type:   Direct-Access                      ANSI SCSI revision: 02
Attached scsi removable disk sda at scsi0, channel 0, id 0, lun 0
SCSI device sda: 256000 512-byte hdwr sectors (131 MB)
sda: Write Protect is off
Partition check:
 /dev/scsi/host0/bus0/target0/lun0: p1
WARNING: USB Mass Storage data integrity not assured
USB Mass Storage device found at 2
USB Mass Storage support registered.

4. Configuration

4.1. Usage as a storage device to extend storage

First install the kernel file system modules, for example: 

ipkg install kmod-vfat

Under Kamikaze 7.07 or later, use 

ipkg install kmod-fs-vfat

TIP: After installing the modules, you should either reboot the device or load the installed modules manually: 

insmod fat
insmod vfat

TIP: You can install support for more file systems by installing the appropriate packages.

File system

Package name

Comment

VFAT/MSDOS

kmod-vfat (kmod-fs-vfat)

File system generally used in USB devices and older Windows

EXT2

kmod-ext2 (kmod-fs-ext2)

EXT3

kmod-ext3 (kmod-fs-ext3)

Now install the fdisk package from the White Russian's backports repository. How to use the backports repository see OpenWrtDocs/Packages. 

ipkg install fdisk

TIP: If you don't find fdisk in the rc6 backports repository, you can use the rc5 backports version: 

ipkg install http://downloads.openwrt.org/backports/rc5/fdisk_2.12r-1_mipsel.ipk

Create the/mntdirectory for the mount point on the flash 

mkdir /mnt

Check what partition you like to mount from your USB device 

fdisk -l

Finally you can mount and use your USB device (with relevant modules for your file system in memory and created directory for mount): 

mount /dev/scsi/host0/bus0/target0/lun0/part1 /mnt

Be happy and use your USB device like on every other GNU/Linux system or create a file server using Samba.

If you go with ext2 with journaling and install kmod-fs-ext2 , kmod-fs-ext3 and e2fsprogs you can use it like a normal unix type disk. Create the script /etc/init.d/usbdrive ( changing the mount point to match yours ) 

#!/bin/sh /etc/rc.common

START=99
STOP=40



start()
{
        echo -n "Testing USB Partition:  "
        e2fsck -p /dev/scsi/host0/bus0/target0/lun0/part1 &
        sleep 5
        echo -n "Mounting USB drive: "                                       
        mount -t ext3 -o noatime /dev/scsi/host0/bus0/target0/lun0/part1 /usb
        echo "Done."
}     
stop()
{                                          
        echo -n "Umounting USB drive:  "   
        sync
        sync                                          
        umount /dev/scsi/host0/bus0/target0/lun0/part1
        echo "Done."
}        
restart()
{           
        stop 
        start
}

then do a ./usbdrive enable

You may need language packages to support the filenames on various file systems:

kmod-nls-base - Kernel modules for basic native language support

kmod-nls-cp437 - Kernel module for codepage 437

kmod-nls-cp850 - Kernel module for codepage 850

kmod-nls-iso8859-1 - Kernel module for iso8859-1 charset support

kmod-nls-iso8859-15 - Kernel module for iso8859-15 charset support

kmod-nls-utf8 - Kernel module for utf8 support

4.2. How do I boot from the USB device (prep)

For this to work you need the same kernel modules for USB as described above. You also need the modules for the EXT3 file system:

/!\ NOTE: IMPORTANT: There are reports that this procedure bricks routers running Kamikaze with 2.6 kernel - proceed at your own risk! (It works for some, not for others) 

ipkg install kmod-ext2 kmod-ext3

After installing the modules, you should either reboot the device or load the installed modules manually: 

insmod ext2
insmod jbd
insmod ext3

The next step is to partition the USB device and create an EXT3 FS partition. This requires fdisk (install it as described above). You can do the partioning in OpenWrt it self or on a normal PC.

In OpenWrt do 

fdisk /dev/sda
-OR-
fdisk /dev/scsi/host0/bus0/target0/lun0/disc

On a GNU/Linux desktop PC do 

fdisk /dev/sda

/!\ IMPORTANT: Make sure you are modifying the right device. If you have any other USB drives, or a SCSI or SATA drive, your USB device might be at /dev/sdb or /dev/sdc (and so on) instead! Also, you do not want to use a partition such as /dev/sda1 (note the number at the end); you do want the base device name.

For more information about using fdisk, see http://www.tldp.org/HOWTO/Partition/fdisk_partitioning.html.

Next, "format" the newly created partition.

In OpenWrt do

For doing this in OpenWrt you first have to install the e2fsprogs package from the White Russian's backports repository. How to use the backports repository see OpenWrtDocs/Packages. 

ipkg install e2fsprogs

Then "format" your partition with 

mke2fs -j /dev/scsi/host0/bus0/target0/lun0/part1

mke2fs may fail on large disks (e.g. 300GB) if there is not enough memory, consider adding a swap partition, even if it is only used during mke2fs.

If you keep getting errors like: 

Creating journal (4096 blocks): mke2fs: No such file or directory
        while trying to create journal

then run the following command: 

ln -s /proc/mounts /etc/mtab

Now, we will copy everything from the flash to the USB device (make sure the EXT3 modules are loaded): 

# mount it
mount -t ext3 /dev/scsi/host0/bus0/target0/lun0/part1 /mnt
# now, we need to mount the root contents somewhere so we can copy
# them without copying /mnt and /proc to the new usb device
mkdir /tmp/root
# if you're using squashfs, you want to copy the squashfs contents,
# not the jffs2 symlinks, so use the command:
mount -o bind /rom /tmp/root
# if you're using jffs2 then use the command /
mount -o bind / /tmp/root
# now /tmp/root contains the root filesystem with no extra directories mounted
# so we just copy this to the usb device
cp /tmp/root/* /mnt -a
# and now we unmount both the usb and our /tmp/root
umount /tmp/root
umount /mnt

/!\ Problems with booting from USB storage were reported with WhiteRussian RC4 or later, which is the version that introduced USB hotplug support. If you encounter problems as well, try disabling USB hotplug. (more info on this?)

As earlier stated on this page (to remove /etc/hotplug.d/usb/01-mount) is NOT a good idea, as this is where usbfs is mounted, so usb-storage might work fine but lsusb wohn't list your devices, and most software using USB won't be able to find devices since /proc/bus/usb will remain empty?

So either remove the file and mount usbfs somewhere else, or everything inside except the line which goes: [ -f /proc/bus/usb/devices ] || mount -t usbfs none /proc/bus/usb

4.3. Boot Configuration - (White Russian)

Next, remove /sbin/init from the JFFS2 partition (this is just a symlink to BusyBox anyway): 

rm /sbin/init

And replace it with this script: 

#!/bin/sh
# change this to your boot partition
boot_dev="/dev/scsi/host0/bus0/target0/lun0/part1"
# install needed modules for usb and the ext3 filesystem
# **NOTE** for usb2.0 replace "uhci" with "ehci-hcd"
# **NOTE** for ohci chipsets replace "uhci" with "usb-ohci"
for module in usbcore uhci scsi_mod sd_mod usb-storage jbd ext3; do {
        insmod $module
}; done
# this may need to be higher if your disk is slow to initialize
sleep 4s
# mount the usb stick
mount "$boot_dev" /mnt
# if everything looks ok, do the pivot root
[ -x /mnt/sbin/init ] && {
        mount -o move /proc /mnt/proc && \
        pivot_root /mnt /mnt/mnt && {
                mount -o move /mnt/dev /dev
                mount -o move /mnt/tmp /tmp
                mount -o move /mnt/jffs2 /jffs2 2>&-
                mount -o move /mnt/sys /sys 2>&-
        }
}
# finally, run the real init (from USB hopefully).
exec /bin/busybox init

Make sure your new /sbin/init is executable: 

chmod a+x /sbin/init

Now just reboot, and if you did everything right it should boot from the USB device automatically.

If it could not boot from the USB device it will boot normally from the file system found on the flash as fallback.

Note that it is safest to leave the 'pivot_root' procedure as an ordinary script file, not part of the code automatically run on startup, at least until you are certain that it is operating as desired. This allows you to recover from any problems created by this script by simply rebooting the router without it.

4.4. Boot Configuration (Kamikaze)

First Create a script /etc/init.d/pivotroot 

#!/bin/sh
# change this to your boot partition
boot_dev="/dev/sda1"
# install needed modules for usb and the ext3 filesystem
# **NOTE** for usb2.0 replace "uhci" with "ehci_hcd"
# **NOTE** for ohci chipsets replace "uhci" with "usb-ohci"
for module in usbcore uhci scsi_mod sd_mod usb-storage jbd kmod-fs-ext2 kmod-fs-ext3 ; do {
        insmod $module
}; done
# this may need to be higher if your disk is slow to initialize
sleep 4s
# mount the usb stick
mount "$boot_dev" /mnt
# if everything looks ok, do the pivot root
[ -x /mnt/sbin/init ] && {
        mount -o move /proc /mnt/proc && \
        pivot_root /mnt /mnt/mnt && {
                mount -o move /mnt/dev /dev
                mount -o move /mnt/tmp /tmp
                mount -o move /mnt/jffs2 /jffs2 2>&-
                mount -o move /mnt/sys /sys 2>&-
        }
}

Note: for Kamikaze 2.4 kernel that may not have hotplug2 then try using this instead. Tested with openwrt-brcm-2.4-squashfs. 

#!/bin/sh
# change this to your boot partition
boot_dev="/dev/discs/disc0/part1"
# install needed modules for usb and the ext3 filesystem
# **NOTE** for usb2.0 replace "uhci" with "ehci-hcd"
# **NOTE** for ohci chipsets replace "uhci" with "usb-ohci"
for module in usbcore uhci scsi_mod sd_mod usb-storage jbd ext2 ext3 ; do {
        insmod $module
}; done
# this may need to be higher if your disk is slow to initialize
sleep 4s
# mount the usb stick
mount "$boot_dev" /mnt
# if everything looks ok, do the pivot root
[ -x /mnt/sbin/init ] && {
        mount -o move /proc /mnt/proc && \
        pivot_root /mnt /mnt/mnt && {
                mount -o move /mnt/dev /dev
                mount -o move /mnt/tmp /tmp
                mount -o move /mnt/jffs /jffs 2>&-
                mount -o move /mnt/sys /sys 2>&-
        }
}

Note: for Kazimate 2.6 kernel, add this before insmod loop. 

/sbin/hotplug2 --override --persistent --max-children 1 --no-coldplug &

And kill it after the loop. 

killall hotplug2

Make it executable: 

chmod +x /etc/init.d/pivotroot

Then install the modules, for Kamikaze 7.07 or later (Kernel 2.6), use 

ipkg install kmod-fs-ext2 kmod-fs-ext3

Test to see if pivotroot works: 

/etc/init.d/pivotroot
df -h

You may safely ignore errors saying "insmod: cannot insert ..." If pivotroot worked, then df will show that your USB storage is mounted on "/" (root). Now reboot. 

reboot

after that edit /etc/init.d/rcS 

#!/bin/sh
# Copyright (C) 2006 OpenWrt.org
if test $2 == "boot" ; then
/etc/init.d/pivotroot
fi
{
        for i in /etc/rc.d/$1*; do
                $i $2 2>&1
        done
} | logger -s -p 6 -t '' &

now your System should Startup nicely either from USB or from internal Flash if the USB-disk is not available.

4.5. Installing and using IPKG packages in mount point other than root

The Optware packages already make use of a similar concept, by which ipkg-opt uses a config file (/opt/etc/ipkg.conf) that points / to /opt in order to force the packages to install there. The settings to control where new packages are installed are defined by single-line entries in /etc/ipkg.conf with the original default being 'root / '. If you have external flash or hard drive, you may want to install packages there and add the corresponding directories to $PATH in /etc/profile.

/!\ NOTE: This is not tested. Please report if it's working for you.

-Works for me (MikkoKorkalo)

/!\ NOTE: PackagesOnExternalMediaHowTo contains additional important infos.

/!\ NOTE: Destination needs not to have trailing slash in order to make following script work (Nijel).

Configure ipkg for a non-root destination 

echo dest usb /mnt/usb >> /etc/ipkg.conf

then install a package to a non-root destination 

ipkg -dest usb install kismet-server

Copy & paste this script into /bin/ipkg-link (or somewhere in your $PATH). 

#!/bin/sh
COMMAND=$1
PACKAGE=$2
setdest () {
        for i in `grep dest /etc/ipkg.conf | cut -d ' ' -f 3`; do
                if [ -f $i/usr/lib/ipkg/info/$PACKAGE.list ]; then
                        DEST=$i
                fi
        done
        if [ "x$DEST" = "x" ]; then
                echo "Can not locate $PACKAGE."
                echo "Check /etc/ipkg.conf for correct dest listings";
                echo "Check name of requested package: $PACKAGE"
                exit 1
        fi
}
addlinks () {
        setdest;
        cat $DEST/usr/lib/ipkg/info/$PACKAGE.list | while read LINE; do
                SRC=$LINE
                DST=`echo $SRC | sed "s|$DEST||"`
                DSTNAME=`basename $DST`
                DSTDIR=`echo $DST | sed "s|$DSTNAME\$||"`
                test -f "$SRC"
                if [ $? = 0 ]; then
                        test -e "$DST"
                        if [ $? = 1 ]; then
                                mkdir -p $DSTDIR
                                ln -sf $SRC $DST
                        else
                                echo "Not linking $SRC to $DST"
                                echo "$DST Already exists"
                        fi
                else
                        test -d "$SRC"
                        if [ $? = 0 ]; then
                                test -e $DST
                                if [ $? = 1 ]; then
                                        mkdir -p $DST
                                else
                                        echo "directory already exists"
                                fi
                        else
                                echo "Source directory $SRC does not exist"
                        fi
                fi
        done
}
removelinks () {
        setdest;
        cat $DEST/usr/lib/ipkg/info/$PACKAGE.list | while read LINE; do
                SRC=$LINE
                DST=`echo $LINE | sed "s|$DEST||"`
                DSTNAME=`basename $DST`
                DSTDIR=`echo $DST | sed "s|$DSTNAME\$||"`
                test -f $DST
                if [ $? = 0 ]; then
                        rm -f $DST
                        test -d $DSTDIR && rmdir $DSTDIR 2>/dev/null
                else
                        test -d $DST
                        if [ $? = 0 ]; then
                                rmdir $DST
                        else
                                echo "$DST does not exist"
                        fi
                fi
        done
}
mountdest () {
        test -d $PACKAGE
        if [ $? = 1 ]; then
                echo "Mount point does not exist"
                exit 1
        fi
        for i in $PACKAGE/usr/lib/ipkg/info/*.list; do
                $0 add `basename $i .list`
        done
}
umountdest () {
        test -d $PACKAGE
        if [ $? = 1 ]; then
                echo "Mount point does not exist"
                exit 1
        fi
        for i in $PACKAGE/usr/lib/ipkg/info/*.list; do
                $0 remove `basename $i .list`
        done
}
case "$COMMAND" in
  add)
        addlinks
  ;;
  remove)
        removelinks
  ;;
  mount)
        mountdest
  ;;
  umount)
        umountdest
  ;;
  *)
        echo "Usage: $0 <cmd> <target>"
        echo "       Commands: add, remove, mount, umount"
        echo "       Targets: <package>, <mount point>"
        echo "Example:  $0 add kismet-server"
        echo "Example:  $0 remove kismet-server"
        echo "Example:  $0 mount /mnt/usb"
        echo "Example:  $0 umount /mnt/usb"
        exit 1
        ;;
esac
exit 0

Make sure the /bin/ipkg-link script is executable: 

chmod a+x /bin/ipkg-link

Examples howto use the script:

Link a single package to root: 

ipkg-link add kismet-server

Link all packages on a mount point to root: 

ipkg-link mount /mnt/usb

Remove symlinks: 

ipkg-link remove kismet-server

Remove all symlinks for all packages: 

ipkg-link umount /mnt/usb

5. Links

UsbStorageHowto (last edited 2008-02-28 18:05:53 by Oconnor)

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