On Fri, 2011-07-08 at 08:47 -0700, Greg KH wrote: > On Fri, Jul 08, 2011 at 05:41:36PM +0200, Kay Sievers wrote: > > On Fri, Jul 8, 2011 at 16:54, Greg KH <greg@xxxxxxxxx> 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 > > > > > > I don't like it and I don't think it will really solve the root problem > > > you are trying to address, but as the patches don't touch any code I > > > maintain, there's not much I can do to object to it. > > > > I can only repeat what I already wrote in detail earlier: > > > > This approach seems to papers over the problem which emitting and > > parsing free-text printk() messages with much-too-dumb tools cause. It > > seems to fix the symptoms not the cause. > > > > You can already write a udev rule today that logs _all_ symlinks of a > > device at discovery time, and any later kernel message can safely be > > associated with all possible names of the blockdev. No kernel changes > > needed, all possible names are covered. That also works good enough > > with our current stone-age tools for anybody who is able to scroll > > back to the last log udev message in that same log file. > > > > There can be by-definition no default udev rules assigning a proper > > single name to a block device. There is never a valid single name for > > a disks, so udev can not ship anything like that in the default setup, > > so this stays as a custom hack. > > > > We absolutely need _structured_ data for logging and error reporting, > > not only to solve this problem. Along with the current free-text > > printk(), we would be able to attach classifications, device > > error/sense data, firmware register dumps and anything > > interesting-for-debug to the messages. > > > > We can't solve that problem in the kernel alone. Structured data from > > the kernel will need to feed a smarter userspace logger that can index > > and classify messages, merge current userspace data into it, and > > provides hooks for the system management to act on critical failures > > and raise notifications. > > > > Structured logging seems like the solution for this and also to many > > other problems in this area. Single custom names pushed into the > > kernel might cover some rather exotic use cases, but I think, is not > > what we are looking for. > > I totally agree, but hey, no one listens to us :) Yes, we did. Everyone agrees structured logging would be the best long term solution. However, it's at least 10x the work presented here, plus it would be a long process getting everyone to agree. This looks like a good 95% interim solution and it can be removed when structured logging makes everything "just work(tm)". I have also seen a couple of other attempts at structured logging which both failed when the people proposing the patches realised how much work it actually was, so I'm a bit sceptical we'll ever get there. But hey, you have the enthusiasm, propose it as a KS topic to get agreement that we should do it and what the format should be and we can go from there. James -- 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
