Fix a bug that caused some /dev entries to continue to exist after

the underlying drive had been hot-unplugged from the system.  Here
is a specific example.  Filesystem code had opened /dev/da1s1e.
Subsequently, the drive was hot-unplugged.  This (correctly) caused
all of the associated /dev/da1* entries to be deleted.  When the
filesystem later realized that the drive was gone it closed the
device, reducing the write-access counts to 0 on the geom providers
for da1s1e, da1s1, and da1.  This caused geom to re-taste the
providers, resulting in the devices being created again.  When the
drive was hot-plugged back in, it resulted in duplicate /dev entries
for da1s1e, da1s1, and da1.

This fix adds a new disk_gone() function which is called by CAM when a
drive goes away.  It orphans all of the providers associated with the
drive, setting an error condition of ENXIO in each one.  In addition,
we prevent a re-taste on last close for writing if an error condition
has been set in the provider.

Sponsored by:   Isilon Systems
Reviewed by:    phk
MFC after:      1 week

2 files changed, 2 insertions, 0 deletions

diff --git a/sys/cam/scsi/scsi_cd.c b/sys/cam/scsi/scsi_cd.c
index d0b2bb2..04f9bb4 100644
--- a/sys/cam/scsi/scsi_cd.c
+++ b/sys/cam/scsi/scsi_cd.c
@@ -407,6 +407,7 @@ cdoninvalidate(struct cam_periph *periph)
 	 && (softc->pinfo.index != CAM_UNQUEUED_INDEX))
 		camq_remove(&softc->changer->devq, softc->pinfo.index);
 
+	disk_gone(softc->disk);
 	xpt_print_path(periph->path);
 	printf("lost device\n");
 }
diff --git a/sys/cam/scsi/scsi_da.c b/sys/cam/scsi/scsi_da.c
index 30b320c..273fadc 100644
--- a/sys/cam/scsi/scsi_da.c
+++ b/sys/cam/scsi/scsi_da.c
@@ -801,6 +801,7 @@ daoninvalidate(struct cam_periph *periph)
 
 	SLIST_REMOVE(&softc_list, softc, da_softc, links);
 
+	disk_gone(softc->disk);
 	xpt_print_path(periph->path);
 	printf("lost device\n");
 }