On Fri, Jul 20, 2007 at 06:14:04PM +0100, Alasdair G Kergon wrote: > On Fri, Jul 20, 2007 at 09:57:28AM -0700, Wood, Brian J wrote: > > Hi Alasdair, I also read in the definition of DM_DEV_CREATE that the > > uuid is optional. Since that is the case shouldn't the failure for not > > having a uuid in "_alloc_thread_status()" be taken out? > > I don't know this code, but in general userspace code should use uuid if it is > present. If it isn't, it should fall back to using the name. Whether that > leads to sensible behaviour in this particular case, I don't know. If it > doesn't then it should be documented that uuid is a requirement. Yes, the uuid here is a requirement, since it is what is used for communication between dmeventd and other userspace components. Using device names is, in my opinion, prone to races and therefore not quite suitable for dmeventd. Moreover, since the dmeventd -only- gets the uuid (from whichever other application it tries to get it), it cannot fall back to name, not knowing it. In fact, when using theh libdevmapper-event library, the client-side code should already fail, if a device has no uuid. In practice, this means that uuid-less devices cannot be monitored, but that is probably a case that is not really important (or is it?). I would probably prefer to just document this as requirement and keep things as they are. Comments? Yours, Peter. -- Peter Rockai | me()mornfall!net | prockai()redhat!com http://blog.mornfall.net | http://web.mornfall.net "In My Egotistical Opinion, most people's C programs should be indented six feet downward and covered with dirt." -- Blair P. Houghton on the subject of C program indentation -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
