From a9b67e69949d20dcb38ea6aaed5500318c7c91f6 Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Wed, 8 May 2019 13:35:57 +0200 Subject: [PATCH] rbd: replace obj_req->tried_parent with obj_req->read_state Make rbd_obj_handle_read() look like a state machine and get rid of the necessity to patch result in rbd_obj_handle_request(), completing the removal of obj_req->xferred and img_req->xferred. Signed-off-by: Ilya Dryomov Reviewed-by: Dongsheng Yang --- drivers/block/rbd.c | 82 ++++++++++++++++++++++++++++++----------------------- 1 file changed, 46 insertions(+), 36 deletions(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index a9b0b23148f9..7925b2fdde79 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -219,6 +219,11 @@ enum obj_operation_type { OBJ_OP_ZEROOUT, }; +enum rbd_obj_read_state { + RBD_OBJ_READ_OBJECT = 1, + RBD_OBJ_READ_PARENT, +}; + /* * Writes go through the following state machine to deal with * layering: @@ -255,7 +260,7 @@ enum rbd_obj_write_state { struct rbd_obj_request { struct ceph_object_extent ex; union { - bool tried_parent; /* for reads */ + enum rbd_obj_read_state read_state; /* for reads */ enum rbd_obj_write_state write_state; /* for writes */ }; @@ -1794,6 +1799,7 @@ static int rbd_obj_setup_read(struct rbd_obj_request *obj_req) rbd_osd_req_setup_data(obj_req, 0); rbd_osd_req_format_read(obj_req); + obj_req->read_state = RBD_OBJ_READ_OBJECT; return 0; } @@ -2402,44 +2408,48 @@ static bool rbd_obj_handle_read(struct rbd_obj_request *obj_req, int *result) struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev; int ret; - if (*result == -ENOENT && - rbd_dev->parent_overlap && !obj_req->tried_parent) { - /* reverse map this object extent onto the parent */ - ret = rbd_obj_calc_img_extents(obj_req, false); - if (ret) { - *result = ret; - return true; - } - - if (obj_req->num_img_extents) { - obj_req->tried_parent = true; - ret = rbd_obj_read_from_parent(obj_req); + switch (obj_req->read_state) { + case RBD_OBJ_READ_OBJECT: + if (*result == -ENOENT && rbd_dev->parent_overlap) { + /* reverse map this object extent onto the parent */ + ret = rbd_obj_calc_img_extents(obj_req, false); if (ret) { *result = ret; return true; } - return false; + if (obj_req->num_img_extents) { + ret = rbd_obj_read_from_parent(obj_req); + if (ret) { + *result = ret; + return true; + } + obj_req->read_state = RBD_OBJ_READ_PARENT; + return false; + } } - } - /* - * -ENOENT means a hole in the image -- zero-fill the entire - * length of the request. A short read also implies zero-fill - * to the end of the request. - */ - if (*result == -ENOENT) { - rbd_obj_zero_range(obj_req, 0, obj_req->ex.oe_len); - *result = 0; - } else if (*result >= 0) { - if (*result < obj_req->ex.oe_len) - rbd_obj_zero_range(obj_req, *result, - obj_req->ex.oe_len - *result); - else - rbd_assert(*result == obj_req->ex.oe_len); - *result = 0; + /* + * -ENOENT means a hole in the image -- zero-fill the entire + * length of the request. A short read also implies zero-fill + * to the end of the request. + */ + if (*result == -ENOENT) { + rbd_obj_zero_range(obj_req, 0, obj_req->ex.oe_len); + *result = 0; + } else if (*result >= 0) { + if (*result < obj_req->ex.oe_len) + rbd_obj_zero_range(obj_req, *result, + obj_req->ex.oe_len - *result); + else + rbd_assert(*result == obj_req->ex.oe_len); + *result = 0; + } + return true; + case RBD_OBJ_READ_PARENT: + return true; + default: + BUG(); } - - return true; } /* @@ -2658,11 +2668,11 @@ static bool rbd_obj_handle_write(struct rbd_obj_request *obj_req, int *result) case RBD_OBJ_WRITE_COPYUP_OPS: return true; case RBD_OBJ_WRITE_READ_FROM_PARENT: - if (*result < 0) + if (*result) return true; - rbd_assert(*result); - ret = rbd_obj_issue_copyup(obj_req, *result); + ret = rbd_obj_issue_copyup(obj_req, + rbd_obj_img_extents_bytes(obj_req)); if (ret) { *result = ret; return true; @@ -2757,7 +2767,7 @@ again: rbd_assert(img_req->result <= 0); if (test_bit(IMG_REQ_CHILD, &img_req->flags)) { obj_req = img_req->obj_request; - result = img_req->result ?: rbd_obj_img_extents_bytes(obj_req); + result = img_req->result; rbd_img_request_put(img_req); goto again; } -- 2.11.0