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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 <idryomov@gmail.com>
Reviewed-by: Dongsheng Yang <dongsheng.yang@easystack.cn>
alistair/sunxi64-5.4-dsi
Ilya Dryomov 2019-05-08 13:35:57 +02:00
parent 54ab3b24c5
commit a9b67e6994
1 changed files with 46 additions and 36 deletions
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82
drivers/block/rbd.c
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@ -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;
}