[44/98] [SCSI] libfc: Fix wrong scsi return status under FC_DATA_UNDRUN

[Greg KH]

2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Yi Zou <yi.zou@xxxxxxxxx>

commit 4347fa66878e079766258bc0d077c350cb31a799 upstream.

This bug is exposed when there is a link flap in LLD. Particularly, when it
happens right after a SCSI write command is sent out, no FCP_DATA is sent,
causing fsp->status_code to be set as FC_DATA_UNDRUN in fc_fcp_complete_locked
even no SCSI status is received. Consequently, fc_io_compl treats this as DID_OK.
This results in SCSI returning successful to the initial I/O request even
there is no DATA actually sent. Particularly, if you run an I/O tool w/ data
verification on, the read back for verification is gonna fail.

This is fixed here by checking when FC_DATA_UNDRUN happens, SCSI status is
received w/ FC_SRB_RCV_STATUS set in fsp->state.

Signed-off-by: Yi Zou <yi.zou@xxxxxxxxx>
Signed-off-by: Robert Love <robert.w.love@xxxxxxxxx>
Signed-off-by: James Bottomley <James.Bottomley@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/scsi/libfc/fc_fcp.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/scsi/libfc/fc_fcp.c
+++ b/drivers/scsi/libfc/fc_fcp.c
@@ -1850,7 +1850,8 @@ static void fc_io_compl(struct fc_fcp_pk
 			 * scsi status is good but transport level
 			 * underrun.
 			 */
-			sc_cmd->result = DID_OK << 16;
+			sc_cmd->result = (fsp->state & FC_SRB_RCV_STATUS ?
+					  DID_OK : DID_ERROR) << 16;
 		} else {
 			/*
 			 * scsi got underrun, this is an error


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