From 7114edac357b8cc27cf95a4d7eed75d07c41970d Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Thu, 1 Feb 2018 11:50:47 +0100 Subject: [PATCH] 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 6d69bb536bac ("rbd: prevent kernel stack blow up on rbd map"). Signed-off-by: Ilya Dryomov --- drivers/block/rbd.c | 68 ++++++++++++++++++++++++++++++++++++--------- 1 file changed, 55 insertions(+), 13 deletions(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 015bd5303f0e..2eb0abd104f5 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -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;