3 files changed, 62 insertions, 4 deletions

diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 6d1cc3df2ac6..1a0faf6370ca 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -679,6 +679,16 @@ static int dispatch_discard_io(struct xen_blkif *blkif,
         return err;
 }
 
+static int dispatch_other_io(struct xen_blkif *blkif,
+                             struct blkif_request *req,
+                             struct pending_req *pending_req)
+{
+        free_req(pending_req);
+        make_response(blkif, req->u.other.id, req->operation,
+                      BLKIF_RSP_EOPNOTSUPP);
+        return -EIO;
+}
+
 static void xen_blk_drain_io(struct xen_blkif *blkif)
 {
         atomic_set(&blkif->drain, 1);
@@ -800,17 +810,30 @@ __do_block_io_op(struct xen_blkif *blkif)
 
                 /* Apply all sanity checks to /private copy/ of request. */
                 barrier();
-                if (unlikely(req.operation == BLKIF_OP_DISCARD)) {
+
+                switch (req.operation) {
+                case BLKIF_OP_READ:
+                case BLKIF_OP_WRITE:
+                case BLKIF_OP_WRITE_BARRIER:
+                case BLKIF_OP_FLUSH_DISKCACHE:
+                        if (dispatch_rw_block_io(blkif, &req, pending_req))
+                                goto done;
+                        break;
+                case BLKIF_OP_DISCARD:
                         free_req(pending_req);
                         if (dispatch_discard_io(blkif, &req))
-                                break;
-                } else if (dispatch_rw_block_io(blkif, &req, pending_req))
+                                goto done;
+                        break;
+                default:
+                        if (dispatch_other_io(blkif, &req, pending_req))
+                                goto done;
                         break;
+                }
 
                 /* Yield point for this unbounded loop. */
                 cond_resched();
         }
-
+done:
         return more_to_do;
 }
 
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index 6072390c7f57..195278ae993d 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -77,11 +77,18 @@ struct blkif_x86_32_request_discard {
         uint64_t       nr_sectors;
 } __attribute__((__packed__));
 
+struct blkif_x86_32_request_other {
+        uint8_t        _pad1;
+        blkif_vdev_t   _pad2;
+        uint64_t       id;           /* private guest value, echoed in resp  */
+} __attribute__((__packed__));
+
 struct blkif_x86_32_request {
         uint8_t        operation;    /* BLKIF_OP_???                         */
         union {
                 struct blkif_x86_32_request_rw rw;
                 struct blkif_x86_32_request_discard discard;
+                struct blkif_x86_32_request_other other;
         } u;
 } __attribute__((__packed__));
 
@@ -113,11 +120,19 @@ struct blkif_x86_64_request_discard {
         uint64_t       nr_sectors;
 } __attribute__((__packed__));
 
+struct blkif_x86_64_request_other {
+        uint8_t        _pad1;
+        blkif_vdev_t   _pad2;
+        uint32_t       _pad3;        /* offsetof(blkif_..,u.discard.id)==8   */
+        uint64_t       id;           /* private guest value, echoed in resp  */
+} __attribute__((__packed__));
+
 struct blkif_x86_64_request {
         uint8_t        operation;    /* BLKIF_OP_???                         */
         union {
                 struct blkif_x86_64_request_rw rw;
                 struct blkif_x86_64_request_discard discard;
+                struct blkif_x86_64_request_other other;
         } u;
 } __attribute__((__packed__));
 
@@ -278,6 +293,11 @@ static inline void blkif_get_x86_32_req(struct blkif_request *dst,
                 dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
                 break;
         default:
+                /*
+                 * Don't know how to translate this op. Only get the
+                 * ID so failure can be reported to the frontend.
+                 */
+                dst->u.other.id = src->u.other.id;
                 break;
         }
 }
@@ -309,6 +329,11 @@ static inline void blkif_get_x86_64_req(struct blkif_request *dst,
                 dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
                 break;
         default:
+                /*
+                 * Don't know how to translate this op. Only get the
+                 * ID so failure can be reported to the frontend.
+                 */
+                dst->u.other.id = src->u.other.id;
                 break;
         }
 }
diff --git a/include/xen/interface/io/blkif.h b/include/xen/interface/io/blkif.h
index 01c3d62436ef..ffd4652de91c 100644
--- a/include/xen/interface/io/blkif.h
+++ b/include/xen/interface/io/blkif.h
@@ -138,11 +138,21 @@ struct blkif_request_discard {
         uint8_t        _pad3;
 } __attribute__((__packed__));
 
+struct blkif_request_other {
+        uint8_t      _pad1;
+        blkif_vdev_t _pad2;        /* only for read/write requests         */
+#ifdef CONFIG_X86_64
+        uint32_t     _pad3;        /* offsetof(blkif_req..,u.other.id)==8*/
+#endif
+        uint64_t     id;           /* private guest value, echoed in resp  */
+} __attribute__((__packed__));
+
 struct blkif_request {
         uint8_t        operation;    /* BLKIF_OP_???                         */
         union {
                 struct blkif_request_rw rw;
                 struct blkif_request_discard discard;
+                struct blkif_request_other other;
         } u;
 } __attribute__((__packed__));