rbd: whole-object write and zeroout should copyup when snapshots exist

Otherwise, once the parent snapshot is removed, the clone's snapshot
wouldn't reflect the state of the clone prior to whole-object write or
zeroout because a deep-copyup was never done ("rbd flatten" wouldn't do
it because the modified object would exist in HEAD).

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 4befd8f6ac9c41e96ba514c55aac790f4ab9e11b..ccfbed8741b8dd56bdc29a774019896b21c85a57 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -1445,7 +1445,8 @@ static bool rbd_obj_is_tail(struct rbd_obj_request *obj_req)
 static bool rbd_obj_copyup_enabled(struct rbd_obj_request *obj_req)
 {
        if (!obj_req->num_img_extents ||
-           rbd_obj_is_entire(obj_req))
+           (rbd_obj_is_entire(obj_req) &&
+            !obj_req->img_request->snapc->num_snaps))
                return false;
 
        return true;
@@ -1955,7 +1956,8 @@ static int count_zeroout_ops(struct rbd_obj_request *obj_req)
 {
        int num_osd_ops;
 
-       if (rbd_obj_is_entire(obj_req) && obj_req->num_img_extents)
+       if (rbd_obj_is_entire(obj_req) && obj_req->num_img_extents &&
+           !rbd_obj_copyup_enabled(obj_req))
                num_osd_ops = 2; /* create + truncate */
        else
                num_osd_ops = 1; /* delete/truncate/zero */
@@ -1970,8 +1972,9 @@ static void __rbd_obj_setup_zeroout(struct rbd_obj_request *obj_req,
 
        if (rbd_obj_is_entire(obj_req)) {
                if (obj_req->num_img_extents) {
-                       osd_req_op_init(obj_req->osd_req, which++,
-                                       CEPH_OSD_OP_CREATE, 0);
+                       if (!rbd_obj_copyup_enabled(obj_req))
+                               osd_req_op_init(obj_req->osd_req, which++,
+                                               CEPH_OSD_OP_CREATE, 0);
                        opcode = CEPH_OSD_OP_TRUNCATE;
                } else {
                        osd_req_op_init(obj_req->osd_req, which++,
@@ -2551,7 +2554,6 @@ static int rbd_obj_issue_copyup_ops(struct rbd_obj_request *obj_req, u32 bytes)
                __rbd_obj_setup_write(obj_req, which);
                break;
        case OBJ_OP_ZEROOUT:
-               rbd_assert(!rbd_obj_is_entire(obj_req));
                __rbd_obj_setup_zeroout(obj_req, which);
                break;
        default: