Re: [RFC PATCH 0/4] Persistent device name using alias name

[Greg KH]

On Fri, Jul 08, 2011 at 09:45:01PM +0200, Karel Zak wrote:
> On Fri, Jul 08, 2011 at 05:45:47PM +0900, Nao Nishijima wrote:
> > 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
> > 
> 
> [...]
> 
> > [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
> 
>  If there is not /dev/foo and /sys/block/foo then the patch introduces
>  a REGRESSION. 
>  
>  The names from /proc/partitions are used in many applications
>  (libblkid, fdisk, ...) for many many years. The applications will not
>  work as expected.
> 
>  It's crazy to assume that all the applications will be improved to
>  translate the "pretty name" from /proc/partitions by /sys/block/<maj>:<min>.
> 
>  Note, it's pretty naive to expect that people will use the pretty
>  names for printk()/dmesg only. I'm absolutely sure that it's will be
>  expected (by end-users) in /etc/fstab, mount, df, fdisk, ...
> 
>  It's will be necessary to modify all these utils. 

And it would be even easier, to just modify the utilities in the first
place to handle the symlink names in /dev/disk that are there today, and
leave the kernel alone.

With the above information you provided, I don't see how we can accept
this patch at all as it will break existing userspace utilities which is
not allowed.

thanks,

greg k-h
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