Sorry for the delay. On Tue, 15 Apr 2008 12:45:23 +1000 "ronnie sahlberg" <[EMAIL PROTECTED]> wrote:
> On Tue, Apr 15, 2008 at 10:23 AM, FUJITA Tomonori > <[EMAIL PROTECTED]> wrote: > > > Let me review the changes to the core first. > > > > Once we agree on the changes to the core, please send them as separate > > patches. Then you can post mmc patches as you like, a single patch or > > multiple patches. I'm fine with either way. > > Great, thanks. > Thinking about it, it might not be necessary to be able to create a > LUN which lacks a backing store, so that part of my proposed patch > it probably a mistake. > > The semantics in core and tgtadm that i think would be useful for > devices such as MMC, and probably also SSC, that support > removable/ejectable media would be > 1, ability to administratively make LUNs online/offline. Such offline > LUNs would still show up in report luns and be accessable, but the LUN > when in offline > would behave as if there was no media loaded. > 2, something similar to the two added lun methods : > lu_online/lu_offline which are called when the online/offline > attribute changes. > So that the lun emulation cna perform additional, commandset > specific actions when the online attribute changes. > For MMC, I think online/offline would map very nicely to "media is > inserted"/"no media loaded". > For MMC I think it would make sense to let the LUN close the > backend file completely when the device goes offline and reopen it > again > when the backend file goes online. Thus > offline/replacefile/online would be similar to eject tray/replace > disk/close tray on a real physical device. > > I think that for SSC it would also make sense to have the emulation > for this commandset also be informed/called on any/all changes on the > online attribute > in case SSC would want to map this and change its behaviour to map > "tape is inserted"/"no tape loaded". > > > Maybe there are better ways to implement this than lu_online/offline > methods for the lun. Though, for removable media it would be nice if > the offline/online cycle did close and reopen the backingstore file > incase one wants to "swap the media" while the device is offline. How about the following scheme? - we add new hooks to device_type_template, online/offlne/reload. - tgtadm can control the above methods. - we let users to create a new logical unit without a backing-store file. In this case, the logical unit is set to offline automatically. - 'reload' method enables users to bind a new backing-store file to a logical unit. - 'reload' method works against only a offline logical unit (an online logical unit could have outstanding commands and accept new commands). - If offline logical units behaves as if there was no media loaded if they are removable/ejectable media. _______________________________________________ Stgt-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/stgt-devel
