storvsc: force discovery of LUNs that may have been removed.
The host asks the guest to scan when a LUN is removed or added.
The only way a guest can identify the removed LUN is when an I/O is
attempted on a removed LUN - the SRB status code indicates that the LUN
is invalid. We currently handle this SRB status and remove the device.
Rather than waiting for an I/O to remove the device, force the discovery of
LUNs that may have been removed prior to discovering LUNs that may have
been added.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index ab0bb98..ae8293a 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -414,10 +414,36 @@
{
struct storvsc_scan_work *wrk;
struct Scsi_Host *host;
+ struct scsi_device *sdev;
+ unsigned long flags;
wrk = container_of(work, struct storvsc_scan_work, work);
host = wrk->host;
+ /*
+ * Before scanning the host, first check to see if any of the
+ * currrently known devices have been hot removed. We issue a
+ * "unit ready" command against all currently known devices.
+ * This I/O will result in an error for devices that have been
+ * removed. As part of handling the I/O error, we remove the device.
+ *
+ * When a LUN is added or removed, the host sends us a signal to
+ * scan the host. Thus we are forced to discover the LUNs that
+ * may have been removed this way.
+ */
+ mutex_lock(&host->scan_mutex);
+ spin_lock_irqsave(host->host_lock, flags);
+ list_for_each_entry(sdev, &host->__devices, siblings) {
+ spin_unlock_irqrestore(host->host_lock, flags);
+ scsi_test_unit_ready(sdev, 1, 1, NULL);
+ spin_lock_irqsave(host->host_lock, flags);
+ continue;
+ }
+ spin_unlock_irqrestore(host->host_lock, flags);
+ mutex_unlock(&host->scan_mutex);
+ /*
+ * Now scan the host to discover LUNs that may have been added.
+ */
scsi_scan_host(host);
kfree(wrk);