It need to copyup the parent's content when layered writing,
but an entire object write would overwrite it, so skip it.
Signed-off-by: Guangliang Zhao <lucienchao@xxxxxxxxx>
---
drivers/block/rbd.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index b365e0d..965b9b9 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2629,12 +2629,14 @@ static int rbd_img_obj_request_submit(struct rbd_obj_request *obj_request)
struct rbd_img_request *img_request;
struct rbd_device *rbd_dev;
bool known;
+ u64 obj_size;
rbd_assert(obj_request_img_data_test(obj_request));
img_request = obj_request->img_request;
rbd_assert(img_request);
rbd_dev = img_request->rbd_dev;
+ obj_size = (u64) 1 << rbd_dev->header.obj_order;
/*
* Only writes to layered images need special handling.
@@ -2644,11 +2646,15 @@ static int rbd_img_obj_request_submit(struct rbd_obj_request *obj_request)
* simple object requests. Finally, if the target object is
* known to already exist, its parent data has already been
* copied, so a write to the object can also be handled as a
- * simple object request.
+ * simple object request. Another type: if the obj_request
+ * aligns with the boundary and equals to the size of an object,
+ * it doesn't need copyup, because the obj_request will overwrite
+ * it finally.
*/
if (!img_request_write_test(img_request) ||
!img_request_layered_test(img_request) ||
rbd_dev->parent_overlap <= obj_request->img_offset ||
+ ((!obj_request->offset) && (obj_request->length == obj_size)) ||
((known = obj_request_known_test(obj_request)) &&
obj_request_exists_test(obj_request))) {
--
1.7.9.5
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