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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>
This commit is contained in:
K. Y. Srinivasan 2014-12-16 13:21:43 -08:00 committed by Christoph Hellwig
parent 2a09ed3d97
commit 34a716bc34
1 changed files with 26 additions and 0 deletions
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26
drivers/scsi/storvsc_drv.c
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@ -414,10 +414,36 @@ static void storvsc_host_scan(struct work_struct *work)
{
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);