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rbd: new request completion code 

Do away with partial request completions and all the associated
complexity.  Individual object requests no longer need to be completed
in order -- when the last one becomes ready, we complete the entire
higher level request all at once.

This also wraps up the conversion to a state machine model and
eliminates the recursion described in commit 6d69bb536b ("rbd:
prevent kernel stack blow up on rbd map").

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Ilya Dryomov 2018-02-01 11:50:47 +01:00
parent efbd1a1106
commit 7114edac35
1 changed files with 55 additions and 13 deletions
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68
drivers/block/rbd.c
View File

@ -327,6 +327,7 @@ struct rbd_img_request {
int result; /* first nonzero obj_request result */
u32 obj_request_count;
u32 pending_count;
struct list_head obj_requests; /* rbd_obj_request structs */
struct kref kref;
@ -1406,6 +1407,7 @@ static inline void rbd_img_obj_request_add(struct rbd_img_request *img_request,
obj_request_img_data_set(obj_request);
rbd_assert(obj_request->which != BAD_WHICH);
img_request->obj_request_count++;
img_request->pending_count++;
list_add_tail(&obj_request->links, &img_request->obj_requests);
dout("%s: img %p obj %p w=%u\n", __func__, img_request, obj_request,
obj_request->which);
@ -1451,10 +1453,6 @@ static void rbd_obj_request_submit(struct rbd_obj_request *obj_request)
dout("%s %p object_no %016llx %llu~%llu osd_req %p\n", __func__,
obj_request, obj_request->object_no, obj_request->offset,
obj_request->length, osd_req);
if (obj_request_img_data_test(obj_request)) {
WARN_ON(obj_request->callback != rbd_img_obj_callback);
rbd_img_request_get(obj_request->img_request);
}
ceph_osdc_start_request(osd_req->r_osdc, osd_req, false);
}
@ -2236,8 +2234,6 @@ static void rbd_img_request_submit(struct rbd_img_request *img_request)
rbd_img_request_put(img_request);
}
static void rbd_img_end_child_request(struct rbd_img_request *img_req);
static int rbd_obj_read_from_parent(struct rbd_obj_request *obj_req,
u64 img_offset, u32 bytes)
{
@ -2249,8 +2245,6 @@ static int rbd_obj_read_from_parent(struct rbd_obj_request *obj_req,
if (!child_img_req)
return -ENOMEM;
child_img_req->callback = rbd_img_end_child_request;
if (!rbd_img_is_write(img_req)) {
switch (obj_req->type) {
case OBJ_REQUEST_BIO:
@ -2386,8 +2380,6 @@ static int rbd_obj_issue_copyup(struct rbd_obj_request *obj_req, u32 bytes)
}
rbd_obj_request_submit(obj_req);
/* FIXME: in lieu of rbd_img_obj_callback() */
rbd_img_request_put(obj_req->img_request);
return 0;
}
@ -2540,6 +2532,29 @@ static bool __rbd_obj_handle_request(struct rbd_obj_request *obj_req)
}
}
static void rbd_obj_end_request(struct rbd_obj_request *obj_req)
{
struct rbd_img_request *img_req = obj_req->img_request;
rbd_assert((!obj_req->result &&
obj_req->xferred == obj_req->length) ||
(obj_req->result < 0 && !obj_req->xferred));
if (!obj_req->result) {
img_req->xferred += obj_req->xferred;
return;
}
rbd_warn(img_req->rbd_dev,
"%s at objno %llu %llu~%llu result %d xferred %llu",
obj_op_name(img_req->op_type), obj_req->object_no,
obj_req->offset, obj_req->length, obj_req->result,
obj_req->xferred);
if (!img_req->result) {
img_req->result = obj_req->result;
img_req->xferred = 0;
}
}
static void rbd_img_end_child_request(struct rbd_img_request *img_req)
{
struct rbd_obj_request *obj_req = img_req->obj_request;
@ -2549,17 +2564,44 @@ static void rbd_img_end_child_request(struct rbd_img_request *img_req)
obj_req->result = img_req->result;
obj_req->xferred = img_req->xferred;
rbd_img_request_put(img_req);
}
rbd_obj_handle_request(obj_req);
static void rbd_img_end_request(struct rbd_img_request *img_req)
{
rbd_assert(!test_bit(IMG_REQ_CHILD, &img_req->flags));
rbd_assert((!img_req->result &&
img_req->xferred == blk_rq_bytes(img_req->rq)) ||
(img_req->result < 0 && !img_req->xferred));
blk_mq_end_request(img_req->rq,
errno_to_blk_status(img_req->result));
rbd_img_request_put(img_req);
}
static void rbd_obj_handle_request(struct rbd_obj_request *obj_req)
{
struct rbd_img_request *img_req;
again:
if (!__rbd_obj_handle_request(obj_req))
return;
obj_request_done_set(obj_req);
rbd_obj_request_complete(obj_req);
img_req = obj_req->img_request;
spin_lock(&img_req->completion_lock);
rbd_obj_end_request(obj_req);
rbd_assert(img_req->pending_count);
if (--img_req->pending_count) {
spin_unlock(&img_req->completion_lock);
return;
}
spin_unlock(&img_req->completion_lock);
if (test_bit(IMG_REQ_CHILD, &img_req->flags)) {
obj_req = img_req->obj_request;
rbd_img_end_child_request(img_req);
goto again;
}
rbd_img_end_request(img_req);
}
static const struct rbd_client_id rbd_empty_cid;