(2011/06/17 1:14), Greg KH wrote: > On Thu, Jun 16, 2011 at 11:50:54AM -0400, James Bottomley wrote: >>> And again, why not just fix the userspace tools? That is trivial to do >>> so and again, could have been done by now in the years this has been >>> discussed. >> >> So I can summarise where I think we are in these discussions: >> >> We provide the ability to give all kernel devices a "preferred name". >> By default this will be the device name the kernel would have originally >> assigned. the dev_printk's will use the preferred name, and it will be >> modifiable from user space. All the kernel will do is print out >> whatever it is ... no guarantees of uniqueness or specific format will >> be made. Since we're only providing one preferred_name file, the kernel >> can only have one preferred name for a device at any given time >> (although it is modifiable on the fly as many times as the user >> chooses). >> >> The design is to use this preferred name to implement what Hitachi wants >> in terms of persistent name, but we don't really care. >> >> All userspace naming will be taken care of by the usual udev rules, so >> for disks, something like /dev/disk/by-preferred/<fred> which would be >> the usual symbolic link. > > No, udev can not create such a link after the preferred name is set, as > it has no way of knowing that the name was set. > >> This will ensure that kernel output and udev input are consistent. It >> will still require that user space utilities which derive a name for a >> device will need modifying to print out the preferred name. > > It also doesn't solve the issue of userspace wanting to use such a > "preferred" name in the command line of tools, as there will not be a > link back to the "kernel" name directly in /dev/. Right, this series just add a preferred name interface, and changes a part of kernel messages. > So as userspace tools will still need to be fixed, I don't see how > adding a kernel file for this is going to help any. Well, a bit in that > the kernel log files will look "different", but again, that really isn't > a problem that userspace couldn't also solve with no kernel changes > needed. hmm, He didnt say "this can solve all problems". I think preferred name is just a starting point to solve these problems. Actually, he decided to fix those user space tools to accept persistent symbolic links, and to show it in outputs. It's not complete, but a good starting point, isn't it? Thank you, -- Masami HIRAMATSU Software Platform Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@xxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
