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hot-plugged USB Harddisk executes backup script in /etc/hotplug/usb

DISCUSSION Clemens Koller 2 participants 3 messages Nov 17, 2005 – Nov 18, 2005

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Clemens Koller

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Hello!

I want to start a backup script in /etc/hotplug/usb whenever I connect an external USB harddisk (Maxtor OneTouch 300GB) to our fileserver to make weekly rotating backups.

Kernel: 2.6.14 (not .2 yet)
Platform: i686
System: udev-075

Whenever I plug (turn on) the external harddisk, udevmonitor shows me nice events and my script is called. But it's called TWICE at the same time which leads to mount conflicts and other strange things. If I call my backup script manually, it works fine.

The whole system was working on our "old" fileserver running 2.6.11.5 without udev. The configuration was adopted from the old system, by copying the script called anabackup to /etc/hotplug/usb and adding:

$ cat /etc/hotplug/usb.usermap
# usb module         match_flags idVendor idProduct bcdDevice_lo bcdDevice_hi bDeviceClass bDeviceSubClass bDeviceProtocol bInterfaceClass bInterfaceSubClass bInterfaceProtocol driver_info
anabackup       0x03 0x0d49 0x7000 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0

The distribution is a fresh installation of a CRUX Linux 2.1 (from scratch) system without strange bells and whistles. I updated from udev-071 to udev-075 but the behaviour didn't change.

Any ideas, what's wrong here?

Thanks in advance,

Clemens

-----------------------------------------------------------------------------
PLUGGING:

$ tail -f /var/log/messages
Nov 17 17:04:09 rio kernel: usb 1-1: new high speed USB device using ehci_hcd and address 7
Nov 17 17:04:09 rio kernel: scsi5 : SCSI emulation for USB Mass Storage devices
Nov 17 17:04:14 rio kernel:   Vendor: Maxtor    Model: OneTouch          Rev: 0201
Nov 17 17:04:14 rio kernel:   Type:   Direct-Access                      ANSI SCSI revision: 00
Nov 17 17:04:14 rio kernel: SCSI device sda: 585938944 512-byte hdwr sectors (300001 MB)
Nov 17 17:04:14 rio kernel: sda: assuming drive cache: write through
Nov 17 17:04:14 rio kernel: SCSI device sda: 585938944 512-byte hdwr sectors (300001 MB)
Nov 17 17:04:14 rio kernel: sda: assuming drive cache: write through
Nov 17 17:04:15 rio kernel:  sda: sda1 sda2 sda3
Nov 17 17:04:15 rio kernel: Attached scsi disk sda at scsi5, channel 0, id 0, lun 0
Nov 17 17:04:15 rio scsi.agent[18074]: disk at /devices/pci0000:00/0000:00:0b.2/usb1/1-1/1-1:1.0/host5/target5:0:0/5:0:0:0
Nov 17 17:04:37 rio scsi.agent[18155]: disk at /devices/pci0000:00/0000:00:0b.2/usb1/1-1/1-1:1.0/host5/target5:0:0/5:0:0:0

Note: The last line shows up twice and delayed by several seconds. But a echo "\007" > /dev/console in my script tells me that it gets called twice instantaneously (pairs of beeps).
Well... WHY?! I guess the problem is somewhere around scsi.agent. Wrong kernel configuration? Any ideas where to start debugging?

root@rio:/etc/hotplug/usb$ udevmonitor
udevmonitor prints the received event from the kernel [UEVENT]
and the event which udev sends out after rule processing [UDEV]

UEVENT[1132243449.986726] add@/devices/pci0000:00/0000:00:0b.2/usb1/1-1 UEVENT[1132243449.986851] add@/devices/pci0000:00/0000:00:0b.2/usb1/1-1/1-1:1.0 UEVENT[1132243449.986900] add@/class/scsi_host/host5
UEVENT[1132243449.986944] add@/class/usb_device/usbdev1.7
UEVENT[1132243454.948573] add@/devices/pci0000:00/0000:00:0b.2/usb1/1-1/1-1:1.0/host5/target5:0:0/5:0:0:0 UEVENT[1132243454.996280] add@/block/sda
UEVENT[1132243455.216593] add@/block/sda/sda1
UEVENT[1132243455.216692] add@/block/sda/sda2
UEVENT[1132243455.216738] add@/block/sda/sda3
UEVENT[1132243455.216783] add@/class/scsi_device/5:0:0:0

-----------------------------------------------------------------------------
UNPLUGGING:

$ tail -f /var/log/messages
Nov 17 17:27:58 rio -- MARK --
Nov 17 17:45:33 rio kernel: usb 1-1: USB disconnect, address 7
$ udevmonitor
UEVENT[1132245933.614131] remove@/class/scsi_device/5:0:0:0
UEVENT[1132245933.614221] remove@/block/sda/sda3
UEVENT[1132245933.614269] remove@/block/sda/sda2
UEVENT[1132245933.614314] remove@/block/sda/sda1
UEVENT[1132245933.614360] remove@/block/sda
UEVENT[1132245933.614404] remove@/devices/pci0000:00/0000:00:0b.2/usb1/1-1/1-1:1.0/host5/target5:0:0/5:0:0:0
UEVENT[1132245933.614451] remove@/class/scsi_host/host5
UEVENT[1132245933.614495] remove@/devices/pci0000:00/0000:00:0b.2/usb1/1-1/1-1:1.0
UEVENT[1132245933.614540] remove@/class/usb_device/usbdev1.7
UEVENT[1132245933.614584] remove@/devices/pci0000:00/0000:00:0b.2/usb1/1-1

-----------------------------------------------------------------------------
OTHER INFO

root@rio:/etc/hotplug/usb$ udevinfo -V
udevinfo, version 075
root@rio:/etc/hotplug/usb$ udevinfo -a -p /sys/block/sda

udevinfo starts with the device the node belongs to and then walks up the device chain, to print for every device found, all possibly useful attributes in the udev key format.
Only attributes within one device section may be used together in one rule, to match the device for which the node will be created.

device '/sys/block/sda' has major:minor 8:0
looking at class device '/sys/block/sda':

    KERNEL="sda"
    SUBSYSTEM="block"
    SYSFS{dev}="8:0"
    SYSFS{range}="16"
    SYSFS{removable}="0"
    SYSFS{size}="585938944"
    SYSFS{stat}="       1        0        8       28        0        0        0        0        0       28       28"

follow the "device"-link to the physical device:
looking at the device chain at '/sys/devices/pci0000:00/0000:00:0b.2/usb1/1-1/1-1:1.0/host4/target4:0:0/4:0:0:0':

    BUS="scsi"
    ID="4:0:0:0"
    DRIVER="sd"
    SYSFS{device_blocked}="0"
    SYSFS{iocounterbits}="32"
    SYSFS{iodone_cnt}="0x6"
    SYSFS{ioerr_cnt}="0x0"
    SYSFS{iorequest_cnt}="0x6"
    SYSFS{max_sectors}="240"
    SYSFS{model}="OneTouch        "
    SYSFS{queue_depth}="1"
    SYSFS{queue_type}="none"
    SYSFS{rev}="0201"
    SYSFS{scsi_level}="3"
    SYSFS{state}="running"
    SYSFS{timeout}="30"
    SYSFS{type}="0"
    SYSFS{vendor}="Maxtor  "

looking at the device chain at '/sys/devices/pci0000:00/0000:00:0b.2/usb1/1-1/1-1:1.0/host4/target4:0:0':

    BUS=""
    ID="target4:0:0"
    DRIVER="unknown"

looking at the device chain at '/sys/devices/pci0000:00/0000:00:0b.2/usb1/1-1/1-1:1.0/host4':

    BUS=""
    ID="host4"
    DRIVER="unknown"

looking at the device chain at '/sys/devices/pci0000:00/0000:00:0b.2/usb1/1-1/1-1:1.0':

    BUS="usb"
    ID="1-1:1.0"
    DRIVER="usb-storage"
    SYSFS{bAlternateSetting}=" 0"
    SYSFS{bInterfaceClass}="08"
    SYSFS{bInterfaceNumber}="00"
    SYSFS{bInterfaceProtocol}="50"
    SYSFS{bInterfaceSubClass}="06"
    SYSFS{bNumEndpoints}="03"
    SYSFS{modalias}="usb:v0D49p7000d0200dc00dsc00dp00ic08isc06ip50"

looking at the device chain at '/sys/devices/pci0000:00/0000:00:0b.2/usb1/1-1':

    BUS="usb"
    ID="1-1"
    DRIVER="usb"
    SYSFS{bConfigurationValue}="1"
    SYSFS{bDeviceClass}="00"
    SYSFS{bDeviceProtocol}="00"
    SYSFS{bDeviceSubClass}="00"
    SYSFS{bMaxPacketSize0}="64"
    SYSFS{bMaxPower}="  0mA"
    SYSFS{bNumConfigurations}="1"
    SYSFS{bNumInterfaces}=" 1"
    SYSFS{bcdDevice}="0200"
    SYSFS{bmAttributes}="c0"
    SYSFS{configuration}=""
    SYSFS{devnum}="6"
    SYSFS{idProduct}="7000"
    SYSFS{idVendor}="0d49"
    SYSFS{manufacturer}="Maxtor"
    SYSFS{maxchild}="0"
    SYSFS{product}="OneTouch"
    SYSFS{serial}="A81T990E    "
    SYSFS{speed}="480"
    SYSFS{version}=" 2.00"

looking at the device chain at '/sys/devices/pci0000:00/0000:00:0b.2/usb1':

    BUS="usb"
    ID="usb1"
    DRIVER="usb"
    SYSFS{bConfigurationValue}="1"
    SYSFS{bDeviceClass}="09"
    SYSFS{bDeviceProtocol}="01"
    SYSFS{bDeviceSubClass}="00"
    SYSFS{bMaxPacketSize0}="8"
    SYSFS{bMaxPower}="  0mA"
    SYSFS{bNumConfigurations}="1"
    SYSFS{bNumInterfaces}=" 1"
    SYSFS{bcdDevice}="0206"
    SYSFS{bmAttributes}="e0"
    SYSFS{configuration}=""
    SYSFS{devnum}="1"
    SYSFS{idProduct}="0000"
    SYSFS{idVendor}="0000"
    SYSFS{manufacturer}="Linux 2.6.14 ehci_hcd"
    SYSFS{maxchild}="4"
    SYSFS{product}="EHCI Host Controller"
    SYSFS{serial}="0000:00:0b.2"
    SYSFS{speed}="480"
    SYSFS{version}=" 2.00"

looking at the device chain at '/sys/devices/pci0000:00/0000:00:0b.2':

    BUS="pci"
    ID="0000:00:0b.2"
    DRIVER="ehci_hcd"
    SYSFS{class}="0x0c0320"
    SYSFS{device}="0x3104"
    SYSFS{irq}="5"
    SYSFS{local_cpus}="1"
    SYSFS{modalias}="pci:v00001106d00003104sv00000925sd00001234bc0Csc03i20"
    SYSFS{subsystem_device}="0x1234"
    SYSFS{subsystem_vendor}="0x0925"
    SYSFS{vendor}="0x1106"

looking at the device chain at '/sys/devices/pci0000:00':

    BUS=""
    ID="pci0000:00"
    DRIVER="unknown"

root@rio:/etc/hotplug/usb$

Signature · 22 lines
Clemens Koller
_______________________________
R&D Imaging Devices
Anagramm GmbH
Rupert-Mayer-Str. 45/1
81379 Muenchen
Germany

http://www.anagramm.de
Phone: +49-89-741518-50
Fax: +49-89-741518-19


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#1 lore raw

Re: hot-plugged USB Harddisk executes backup script in /etc/hotplug/usb twice

Quoted 13 lines · Clemens Koller

I want to start a backup script in /etc/hotplug/usb whenever I connect an external USB harddisk (Maxtor OneTouch 300GB) to our fileserver to make weekly rotating backups.

Kernel: 2.6.14 (not .2 yet)
Platform: i686
System: udev-075

Whenever I plug (turn on) the external harddisk, udevmonitor shows me nice events and my script is called. But it's called TWICE at the same time which leads to mount conflicts and other strange things. If I call my backup script manually, it works fine.

Quoted 4 lines

The whole system was working on our "old" fileserver running 2.6.11.5 without udev. The configuration was adopted from the old system, by copying the script called anabackup to /etc/hotplug/usb and adding:

There was no change regarding this, you always get multiple events for different parts of that device and need to act only on one of them. You can probably look if $INTERFACE, or something else, only for one of the events is set in the environment, else just exit. "udevmonitor --env" should show the difference.
Anyway, you better move to udev rules to hook into the events, instead of depending on the weird map stuff, which is not longer supported.

Kay

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author
#2 lore raw
In reply to Clemens Koller

Hello, Kay!

Quoted 7 lines
Quoted 4 lines

Whenever I plug (turn on) the external harddisk, udevmonitor shows me nice events and my script is called. But it's called TWICE at the same time which leads to mount conflicts and other strange things. If I call my backup script manually, it works fine.

There was no change regarding this, you always get multiple events for different parts of that device and need to act only on one of them.

Hmm, okay. What are the different parts of my device?
I can imagine that I get a "part" for the blue OneTouch Button and a "part" for the harddisk itself, but if I have a look at the logs (see my old mail) it says: that there is some code executed twice "kernel: SCSI device sda: ..."
Well, it's simple miss-leading and therefore a bug in the kernel or scsi.agent. 8-P

Quoted 6 lines

You
can probably look if $INTERFACE, or something else, only for one of the events is set in the environment, else just exit. "udevmonitor --env" should show the difference.
Anyway, you better move to udev rules to hook into the events, instead of depending on the weird map stuff, which is not longer supported.

Okay, I removed my stuff from usb.usermap and added a /etc/udev/rules.d/10-local.rules
containing

# /etc/udev/rules/10-local.rules - my udev device naming rules
BUS="usb", KERNEL="sda3", ACTION="add", SYSFS(Manufacturer)="Maxtor*", SYSFS(serial)="A82T450E*", SYMLINK+="backup_disc", RUN="/etc/backup/anabackup"

(I guess that the trailing spaces after Manufacturer or the serial are ignored and I can write "Maxtor" and "A82T450E" without the asterisks, right?)

The interesting thing was, that if I add KERNEL="sd*" or KERNEL="sda", I get my script called three(!) times at the same time!
I guess that this means that the rule gets hit for each partition (sda1..sda3) from that disk and I have to narrow it down to "sda3" which is my actual backup partition.

I expected that if I see the SYSFS(Manufacturer) and SYSFS(serial) only _once_ in the udevmonitor --env output, that I get the rule activated only once, too.
Is that normal behaviour?
What's the reason for that behaviour?
What is scsi_devfs.sh intended to do there?

Another little problem was, that I was missing some documentation in the udevd or udev or udevcontrol man page that udevd detects changes in the rules-file automagically and that it's not necessary to send it a signal as i.e. needed by samba to reload it's configs.

Well, it works now! My five cents...
Thanks!

Signature · 22 lines
Clemens Koller
_______________________________
R&D Imaging Devices
Anagramm GmbH
Rupert-Mayer-Str. 45/1
81379 Muenchen
Germany

http://www.anagramm.de
Phone: +49-89-741518-50
Fax: +49-89-741518-19


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