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>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index c07cb1dbc1c5d4e134ca0a94da7886d31b676523..e1dcd36ae0721d6d5b6003d66102a49275ce8f58 100644 (file)
--- 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. */