xen/blkback: Fix the WRITE_BARRIER

The WRITE_BARRIER was missing the REQ_WRITE option. This
was causing the blktap to die.

Signed-off-by: Tom Goetz <tom.goetz@virtualcomputer.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/drivers/xen/blkback/blkback.c b/drivers/xen/blkback/blkback.c
index a6f8f13381185dbe44dada2a82b8a49019d40cc6..4cd5b49de0c10f30db68e96be1ad4c69bd692a3e 100644 (file)
--- a/drivers/xen/blkback/blkback.c
+++ b/drivers/xen/blkback/blkback.c
@@ -47,6 +47,8 @@
 #include <asm/xen/hypercall.h>
 #include "common.h"
 
+#define WRITE_BARRIER  (REQ_WRITE | REQ_FLUSH | REQ_FUA)
+
 /*
  * These are rather arbitrary. They are fairly large because adjacent requests
  * pulled from a communication ring are quite likely to end up being part of
@@ -420,7 +422,7 @@ static void dispatch_rw_block_io(blkif_t *blkif,
                operation = WRITE;
                break;
        case BLKIF_OP_WRITE_BARRIER:
-               operation = REQ_FLUSH | REQ_FUA;
+               operation = WRITE_BARRIER;
                break;
        default:
                operation = 0; /* make gcc happy */
@@ -429,7 +431,7 @@ static void dispatch_rw_block_io(blkif_t *blkif,
 
        /* Check that number of segments is sane. */
        nseg = req->nr_segments;
-       if (unlikely(nseg == 0 && operation != (REQ_FLUSH | REQ_FUA)) ||
+       if (unlikely(nseg == 0 && operation != WRITE_BARRIER) ||
            unlikely(nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
                DPRINTK("Bad number of segments in request (%d)\n", nseg);
                goto fail_response;
@@ -537,7 +539,7 @@ static void dispatch_rw_block_io(blkif_t *blkif,
        }
 
        if (!bio) {
-               BUG_ON(operation != (REQ_FLUSH | REQ_FUA));
+               BUG_ON(operation != WRITE_BARRIER);
                bio = bio_alloc(GFP_KERNEL, 0);
                if (unlikely(bio == NULL))
                        goto fail_put_bio;
@@ -552,7 +554,7 @@ static void dispatch_rw_block_io(blkif_t *blkif,
 
        if (operation == READ)
                blkif->st_rd_sect += preq.nr_sects;
-       else if (operation == WRITE || operation == (REQ_FLUSH | REQ_FUA))
+       else if (operation == WRITE || operation == WRITE_BARRIER)
                blkif->st_wr_sect += preq.nr_sects;
 
        return;