rbd: use helpers to handle discard for layered images correctly

Only allocate two osd ops for discard requests, since the
preallocation hint is only added for regular writes.  Use
rbd_img_obj_request_fill() to recreate the original write or discard
osd operations, isolating that logic to one place, and change the
assert in rbd_osd_req_create_copyup() to accept discard requests as
well.

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>

1 files changed, 22 insertions, 32 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index c07cb1dbc1c5..e1dcd36ae072 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -1934,9 +1934,10 @@ static struct ceph_osd_request *rbd_osd_req_create(
 }
 
 /*
- * Create a copyup osd request based on the information in the
- * object request supplied.  A copyup request has three osd ops,
- * a copyup method call, a hint op, and a write op.
+ * Create a copyup osd request based on the information in the object
+ * request supplied.  A copyup request has two or three osd ops, a
+ * copyup method call, potentially a hint op, and a write or truncate
+ * or zero op.
  */
 static struct ceph_osd_request *
 rbd_osd_req_create_copyup(struct rbd_obj_request *obj_request)
@@ -1946,18 +1947,24 @@ rbd_osd_req_create_copyup(struct rbd_obj_request *obj_request)
         struct rbd_device *rbd_dev;
         struct ceph_osd_client *osdc;
         struct ceph_osd_request *osd_req;
+        int num_osd_ops = 3;
 
         rbd_assert(obj_request_img_data_test(obj_request));
         img_request = obj_request->img_request;
         rbd_assert(img_request);
-        rbd_assert(img_request_write_test(img_request));
+        rbd_assert(img_request_write_test(img_request) ||
+                        img_request_discard_test(img_request));
 
-        /* Allocate and initialize the request, for the three ops */
+        if (img_request_discard_test(img_request))
+                num_osd_ops = 2;
+
+        /* Allocate and initialize the request, for all the ops */
 
         snapc = img_request->snapc;
         rbd_dev = img_request->rbd_dev;
         osdc = &rbd_dev->rbd_client->client->osdc;
-        osd_req = ceph_osdc_alloc_request(osdc, snapc, 3, false, GFP_ATOMIC);
+        osd_req = ceph_osdc_alloc_request(osdc, snapc, num_osd_ops,
+                                                false, GFP_ATOMIC);
         if (!osd_req)
                 return NULL;    /* ENOMEM */
 
@@ -2337,10 +2344,9 @@ static void rbd_img_obj_request_fill(struct rbd_obj_request *obj_request,
         u16 opcode;
 
         if (op_type == OBJ_OP_DISCARD) {
-                if (!offset && (length == object_size)
-                        && (!img_request_layered_test(img_request) ||
-                                (rbd_dev->parent_overlap <=
-                                        obj_request->img_offset))) {
+                if (!offset && length == object_size &&
+                    (!img_request_layered_test(img_request) ||
+                     !obj_request_overlaps_parent(obj_request))) {
                         opcode = CEPH_OSD_OP_DELETE;
                 } else if ((offset + length == object_size)) {
                         opcode = CEPH_OSD_OP_TRUNCATE;
@@ -2500,7 +2506,8 @@ rbd_img_obj_copyup_callback(struct rbd_obj_request *obj_request)
         struct page **pages;
         u32 page_count;
 
-        rbd_assert(obj_request->type == OBJ_REQUEST_BIO);
+        rbd_assert(obj_request->type == OBJ_REQUEST_BIO ||
+                obj_request->type == OBJ_REQUEST_NODATA);
         rbd_assert(obj_request_img_data_test(obj_request));
         img_request = obj_request->img_request;
         rbd_assert(img_request);
@@ -2538,11 +2545,10 @@ rbd_img_obj_parent_read_full_callback(struct rbd_img_request *img_request)
         struct ceph_osd_client *osdc;
         struct rbd_device *rbd_dev;
         struct page **pages;
+        enum obj_operation_type op_type;
         u32 page_count;
         int img_result;
         u64 parent_length;
-        u64 offset;
-        u64 length;
 
         rbd_assert(img_request_child_test(img_request));
 
@@ -2606,26 +2612,10 @@ rbd_img_obj_parent_read_full_callback(struct rbd_img_request *img_request)
         osd_req_op_cls_request_data_pages(osd_req, 0, pages, parent_length, 0,
                                                 false, false);
 
-        /* Then the hint op */
-
-        osd_req_op_alloc_hint_init(osd_req, 1, rbd_obj_bytes(&rbd_dev->header),
-                                   rbd_obj_bytes(&rbd_dev->header));
-
-        /* And the original write request op */
-
-        offset = orig_request->offset;
-        length = orig_request->length;
-        osd_req_op_extent_init(osd_req, 2, CEPH_OSD_OP_WRITE,
-                                        offset, length, 0, 0);
-        if (orig_request->type == OBJ_REQUEST_BIO)
-                osd_req_op_extent_osd_data_bio(osd_req, 2,
-                                        orig_request->bio_list, length);
-        else
-                osd_req_op_extent_osd_data_pages(osd_req, 2,
-                                        orig_request->pages, length,
-                                        offset & ~PAGE_MASK, false, false);
+        /* Add the other op(s) */
 
-        rbd_osd_req_format_write(orig_request);
+        op_type = rbd_img_request_op_type(orig_request->img_request);
+        rbd_img_obj_request_fill(orig_request, osd_req, op_type, 1);
 
         /* All set, send it off. */