rbd: rework rbd_img_obj_exists_submit() error paths

- don't put obj_request before rbd_obj_request_get() if
  rbd_obj_request_create() fails
- don't leak pages if rbd_obj_request_create() fails
- don't leak stat_request if rbd_osd_req_create() fails

Reported-by: David Disseldorp <ddiss@suse.de>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Reviewed-by: David Disseldorp <ddiss@suse.de>

1 files changed, 22 insertions, 20 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 77675ac8fc4c..3218ac4f2e09 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2894,11 +2894,23 @@ static int rbd_img_obj_exists_submit(struct rbd_obj_request *obj_request)
 {
         struct rbd_device *rbd_dev = obj_request->img_request->rbd_dev;
         struct rbd_obj_request *stat_request;
-        struct page **pages = NULL;
+        struct page **pages;
         u32 page_count;
         size_t size;
         int ret;
 
+        stat_request = rbd_obj_request_create(obj_request->object_name, 0, 0,
+                                              OBJ_REQUEST_PAGES);
+        if (!stat_request)
+                return -ENOMEM;
+
+        stat_request->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_READ, 1,
+                                                   stat_request);
+        if (!stat_request->osd_req) {
+                ret = -ENOMEM;
+                goto fail_stat_request;
+        }
+
         /*
          * The response data for a STAT call consists of:
          *     le64 length;
@@ -2910,38 +2922,28 @@ static int rbd_img_obj_exists_submit(struct rbd_obj_request *obj_request)
         size = sizeof (__le64) + sizeof (__le32) + sizeof (__le32);
         page_count = (u32)calc_pages_for(0, size);
         pages = ceph_alloc_page_vector(page_count, GFP_KERNEL);
-        if (IS_ERR(pages))
-                return PTR_ERR(pages);
+        if (IS_ERR(pages)) {
+                ret = PTR_ERR(pages);
+                goto fail_stat_request;
+        }
 
-        ret = -ENOMEM;
-        stat_request = rbd_obj_request_create(obj_request->object_name, 0, 0,
-                                                        OBJ_REQUEST_PAGES);
-        if (!stat_request)
-                goto out;
+        osd_req_op_init(stat_request->osd_req, 0, CEPH_OSD_OP_STAT, 0);
+        osd_req_op_raw_data_in_pages(stat_request->osd_req, 0, pages, size, 0,
+                                     false, false);
 
         rbd_obj_request_get(obj_request);
         stat_request->obj_request = obj_request;
         stat_request->pages = pages;
         stat_request->page_count = page_count;
-
-        stat_request->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_READ, 1,
-                                                   stat_request);
-        if (!stat_request->osd_req)
-                goto out;
         stat_request->callback = rbd_img_obj_exists_callback;
 
-        osd_req_op_init(stat_request->osd_req, 0, CEPH_OSD_OP_STAT, 0);
-        osd_req_op_raw_data_in_pages(stat_request->osd_req, 0, pages, size, 0,
-                                        false, false);
         rbd_osd_req_format_read(stat_request);
 
         rbd_obj_request_submit(stat_request);
         return 0;
 
-out:
-        if (ret)
-                rbd_obj_request_put(obj_request);
-
+fail_stat_request:
+        rbd_obj_request_put(stat_request);
         return ret;
 }