[dm-devel] failover does not work with rdac device handler
Chandra Seetharaman
sekharan at us.ibm.com
Tue Oct 7 02:04:34 UTC 2008
Hi,
Can you try the attached patch.
chandra
PS: I see a problem (not related to this patch) that the dh_state file
is not getting recreated, still working on it.
-------------
Keep a reference count of attaches, so that same number of detaches are allowed.
Signed-off-by: Chandra Seetharaman <sekharan at us.ibm.com>
---
Index: linux-2.6.27-rc8-git5/drivers/scsi/device_handler/scsi_dh.c
===================================================================
--- linux-2.6.27-rc8-git5.orig/drivers/scsi/device_handler/scsi_dh.c
+++ linux-2.6.27-rc8-git5/drivers/scsi/device_handler/scsi_dh.c
@@ -153,12 +153,26 @@ static int scsi_dh_handler_attach(struct
if (sdev->scsi_dh_data) {
if (sdev->scsi_dh_data->scsi_dh != scsi_dh)
err = -EBUSY;
- } else if (scsi_dh->attach)
+ else
+ kref_get(&sdev->scsi_dh_data.kref);
+ } else if (scsi_dh->attach) {
err = scsi_dh->attach(sdev);
+ if (!err)
+ kref_init(&sdev->scsi_dh_data.kref);
+ }
return err;
}
+static void scsi_dh_release(struct *kref kref)
+{
+ struct scsi_dh_data *scsi_dh_data;
+ scsi_dh_data = container_of(kref, struct scsi_dh_data, kref);
+
+ if (scsi_dh_data->scsi_dh && scsi_dh_data->scsi_dh->detach)
+ scsi_dh_data->scsi_dh->detach(sdev);
+}
+
/*
* scsi_dh_handler_detach - Detach a device handler from a device
* @sdev - SCSI device the device handler should be detached from
@@ -176,11 +190,7 @@ static void scsi_dh_handler_detach(struc
if (scsi_dh && scsi_dh != sdev->scsi_dh_data->scsi_dh)
return;
- if (!scsi_dh)
- scsi_dh = sdev->scsi_dh_data->scsi_dh;
-
- if (scsi_dh && scsi_dh->detach)
- scsi_dh->detach(sdev);
+ kref_put(&sdev->scsi_dh_data.kref, scsi_dh_release);
}
/*
Index: linux-2.6.27-rc8-git5/include/scsi/scsi_device.h
===================================================================
--- linux-2.6.27-rc8-git5.orig/include/scsi/scsi_device.h
+++ linux-2.6.27-rc8-git5/include/scsi/scsi_device.h
@@ -191,6 +191,7 @@ struct scsi_device_handler {
struct scsi_dh_data {
struct scsi_device_handler *scsi_dh;
+ struct kref kref;
char buf[0];
};
More information about the dm-devel
mailing list