From mboxrd@z Thu Jan  1 00:00:00 1970
From: "John Stoffel" <john@stoffel.org>
Date: Mon, 06 Jul 2009 15:58:18 +0000
Subject: howto get serial number of a tape drive?
Message-Id: <19026.7962.882759.229031@stoffel.org>
List-Id: <linux-hotplug.vger.kernel.org>
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To: linux-hotplug@vger.kernel.org


Hi,

I'm trying to make sure that my tape drives get named properly on
bootup in my tape library.  As far as I can determine, the
/lib/udev/scsi_id command requires that you use the SCSI Generic
device for the inquiry.  

How do I map from /dev/st0 to /dev/sg? within a udev rule so I can
pull out the proper serial number?

I've looked at the 60-persistent-storage-tape.rules file, but it
doesn't seem to help, or I'm just being dense somewhere?  

Here's my /etc/udev/rules.d/10-tape.rules file that I'm working with:

  # Sun SCSI DLT7k tape drive - make it /dev/tape by default
  BUS="scsi", SYSFS{model}="DLT7000",SYSFS{vendor}="SUN",SYMLINK="tape"

  # SCSI ATL P1000 Autoloader - make if /dev/changer 
  BUS="scsi", SYSFS{model}="P1000    6220051",SYSFS{vendor}="ATL",SYMLINK="changer"

  #-------------------------------------------------------------------------
  # SCSI ATL P1000 DLT 7000 tape drives
  # SCSI 2 is drive 0 in library, SerialNumber: 'CX752S1059' (left drive)
  # SCSI 3 is drive 1 in library, SerialNumber: 'PXB09S0552' (right drive)

  # ---------
  # Old tape_id script
  # ---------
  #BUS="scsi", KERNEL="nst[0-9]", PROGRAM="/lib/udev/tape_id %k", RESULT="CX752S1059", SYMLINK="dlt7k-left"
  #BUS="scsi", KERNEL="nst[0-9]", PROGRAM="/lib/udev/tape_id %k", RESULT="PXB09S0552", SYMLINK="dlt7k-right"

  # ---------
  # Try using /lib/udev/scsi_id --replace-whitespace --whitelisted
  # ---------

  # SQUANTUM_DLT7000_PXB09S0552

  #SUBSYSTEM="scsi_generic", PROGRAM="/lib/udev/scsi_id --replace-whitespace --whitelisted /dev/%k", RESULT="SQUANTUM_DLT7000_CX752S1059", SYMLINK="dlt7k-left"

  # Match scsi subsystem tape devices, stuff info into $BSG_DEV
  KERNEL="st*[0-9]|nst*[0-9]",           ENV{ID_SERIAL}!="?*", \
	  SUBSYSTEMS="scsi", KERNELS="[0-9]*:*[0-9]", \
	  ENV{BSG_DEV}="$root/bsg/$id"

  # Wait for the $BSG_DEV var to be defined, then run scsi_id on that value
  KERNEL="st*[0-9]|nst*[0-9]",           ENV{ID_SERIAL}!="?*", \
	  WAIT_FOR="$env{BSG_DEV}", \
	  ENV{ID_BUS}="scsi", \
	  IMPORT{program}="/lib/udev/scsi_id --replace-whitespace --whitelisted --export --device=$env{BSG_DEV}"

  KERNEL="st*[0-9]|nst*[0-9]",           ENV{ID_SERIAL}="?*", \
	  SYMLINK+="tape/by-id/$env{ID_BUS}-$env{ID_SERIAL}"

  KERNEL="st*[0-9]",ENV{ID_SERIAL}="SQUANTUM_DLT7000_PXB09S0552", \
	  SYMLINK+="dlt7k-right-st"
  KERNEL="nst*[0-9]",ENV{ID_SERIAL}="SQUANTUM_DLT7000_PXB09S0552", \
	  SYMLINK+="dlt7k-right-nst"

  KERNEL="st*[0-9]|nst*[0-9]", \
	  IMPORT{program}="/lib/udev/path_id $devpath"
  KERNEL="st*[0-9]",                     ENV{ID_PATH}="?*", \
	  SYMLINK+="tape/by-path/$env{ID_PATH}"
  KERNEL="nst*[0-9]",                    ENV{ID_PATH}="?*", \
	  SYMLINK+="tape/by-path/$env{ID_PATH}-nst"


Any hints on how I make this work better would be appreciated.

Thanks,
John