Date: Mon, 23 Jul 2012 16:42:17 +0300 From: Alexander Motin <mav@FreeBSD.org> To: freebsd-scsi@freebsd.org, freebsd-geom@FreeBSD.org Cc: Kris Moore <kris@pcbsd.org> Subject: [RFC] CAM/GEOM media change notification Message-ID: <500D54B9.1010800@FreeBSD.org>
next in thread | raw e-mail | index | archive | help
Hi. On PC-BSD developers request and sponsored by iXsystems, Inc, I've made patch for present FreeBSD 10-CURRENT implementing media change notification for DA and CD removable media devices, that I would like to be reviewed and tested. It includes three parts: 1) Modifications to CAM to detect media media changes and report them to disk(9) layer. For modern SATA (and potentially UAS) devices it utilizes Asynchronous Notification mechanism to receive events from hardware. Active polling with TEST UNIT READY commands with 3 seconds period is used for incapable hardware. After that both CD and DA drivers work the same way, detecting two conditions: "NOT READY: Medium not present" after medium was detected previously, and "UNIT ATTENTION: Not ready to ready change, medium may have changed". First one reported to disk(9) as media removal, second as media insert/change. To reliably receive second event new AC_UNIT_ATTENTION async added to make UAs broadcasted to all periphs by generic error handling code. 2) Modifications to GEOM core to handle media remove and change events. Media removal handled by spoiling all consumers attached to the provider. Media change event also schedules provider retaste after spoiling to probe new media. New flag G_CF_ORPHAN was added to consumers to reflect that consumer is in process of destruction. It allows retaste to create new geom instance of the same class, while previous one is still dying. 3) Modifications to several major GEOM classes: DEV -- to report media change events to devd; VFS -- to handle spoiling same as orphan to prevent accessing replaced media. PART class already handles spoiling alike to orphan. As result, such events are reported to devd for USB card reader: - on media inserted: !system=DEVFS subsystem=CDEV type=MEDIACHANGE cdev=da3 !system=DEVFS subsystem=CDEV type=CREATE cdev=da3s1 !system=DEVFS subsystem=CDEV type=CREATE cdev=msdosfs/NIKON D7000 - on media removed: !system=DEVFS subsystem=CDEV type=DESTROY cdev=da3s1 !system=DEVFS subsystem=CDEV type=DESTROY cdev=msdosfs/NIKON D7000 Patch can be found here: http://people.freebsd.org/~mav/mediachange8.patch Any comments/objections/propositions? -- Alexander Motin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?500D54B9.1010800>