Messages in this thread | | | From | Nao Nishijima <> | Subject | [RFC PATCH 0/4] Persistent device name using alias name | Date | Fri, 08 Jul 2011 17:45:47 +0900 |
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Hi,
This patch series provides an "alias name" of the disk into kernel and procfs messages. The user can assign a preferred name to an alias name of the device.
Based on previous discussion (*), I changed patches as follows - This is "alias name" - An "alias name" is stored in gendisk struct - Add document to Documentation/ABI/testing/sysfs-block - When the user changes an "alias name", kernel notifies udev
(*) http://marc.info/?l=linux-scsi&m=130812625531219&w=2
How to use: 1. Build and install the kernel with this series, and reboot with the kernel.
2. Check device names.
[localhost]# cat /proc/partitions major minor #blocks name
8 0 12582912 sda 8 1 12582878 sda1 8 0 8388608 sdb 8 1 512000 sdb1 8 2 7875584 sdb2
3. Make a script of get alias_name
[localhost]# vi /lib/udev/get_alias_name #!/bin/sh -e DEVNAME=`echo $1 | sed -e 's/[0-9]//g'` echo "ALIAS=`cat /sys/block/$DEVNAME/alias_name`" exit 0
And you should set an execute bit, [localhost]# chmod +x /lib/udev/get_alias_name
4. Check disk's id Here is an example to get the serial id and the path of the device. Some devices have not the serial id. Therefore, to identify a device, users need to get the path of the device.
[localhost]# udevadm info --query=property --path=/sys/block/sda \ | grep ID_SERIAL= ID_SERIAL=0QEMU_QEMU_HARDDISK_drive-scsi0-0-1
or you can also use the path of the device
[localhost]# udevadm info --query=property --path=/sys/block/sr0 \ | grep ID_PATH= ID_PATH=pci-0000:00:01.1-scsi-1:0:0:0
5. Write udev rules as follows (The user assigns "foo" to sda and "bar" to sr0) We use ENV{ID_SERIAL} or ENV{ID_PATH} (get by 3) to identify a disk. And to assign automatically an "alias name", we use ATTR key. If ENV{ALIAS} is empty, we use to get an "alias_name" by get_alias_name script.
[localhost]# vi /etc/udev/rules.d/70-alias_name.rules SUBSYSTEM!="block", GOTO="end"
# write alias name for sdX KERNEL=="sd*[!0-9]", ACTION=="add", ATTR{alias_name}="foo", \ ENV{ID_SERIAL}=="0QEMU_QEMU_HARDDISK_drive-scsi0-0-1"
# write alias name for srX KERNEL=="sr[0-9]", ACTION=="add", ATTR{alias_name}="bar", \ ENV{ID_PATH}=="pci-0000:00:01.1-scsi-1:0:0:0"
# make symlink ENV{DEVTYPE}=="disk", ENV{ALIAS}=="?*", SYMLINK+="disk/by-alias/$env{ALIAS}" ENV{DEVTYPE}=="partition", ENV{ALIAS}=="", \ IMPORT{program}="/lib/udev/get_alias_name %k" ENV{DEVTYPE}=="partition", ENV{ALIAS}=="?*", \ SYMLINK+="disk/by-alias/$env{ALIAS}%n"
LABEL="end"
6. reboot After reboot, we can see alias name in kernel and procfs messages.
[localhost]# ls -l /dev/disk/by-alias/ total 0 lrwxrwxrwx. 1 root root 9 Jul 1 21:21 bar -> ../../sr0 lrwxrwxrwx. 1 root root 9 Jul 1 21:21 foo -> ../../sda lrwxrwxrwx. 1 root root 10 Jul 1 21:21 foo1 -> ../../sda1
[localhost]# dmesg ... sd 2:0:1:0: [sda] Attached SCSI disk alias_name: assigned foo to sda EXT4-fs (foo1): warning: maximal mount count reached, running e2fsck is recommended EXT4-fs (foo1): mounted filesystem with ordered data mode. Opts: (null) ...
[localhost]# cat /proc/partitions major minor #blocks name
8 0 12582912 foo 8 1 12582878 foo1 8 0 8388608 sdb 8 1 512000 sdb1 8 2 7875584 sdb2
When a new device is added, the udev appends a new rule manually. In the future, it is appended automatically, as like NIC.
TODO: - Modify blkid to show "alias name"
Best Regards,
---
Nao Nishijima (4): sd: cleanup for alias name fs: modify disk_name() for alias name sd: modify printk for alias_name block: add a new attribute "alias name" in gendisk structure
Documentation/ABI/testing/sysfs-block | 15 ++++++ block/genhd.c | 85 +++++++++++++++++++++++++++++++++ drivers/scsi/sd.c | 7 ++- drivers/scsi/sd.h | 2 - fs/partitions/check.c | 6 +- include/linux/genhd.h | 4 ++ include/scsi/scsi_device.h | 3 + 7 files changed, 114 insertions(+), 8 deletions(-)
-- Nao Nishijima (nao.nishijima.xt@hitachi.com)
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