From 6e2a4505dba0cae8faa701426185dfb7b49f537c Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Wed, 27 Mar 2013 09:16:30 -0500 Subject: [PATCH] rbd: don't zero-fill non-image object requests A result of ENOENT from a read request for an object that's part of an rbd image indicates that there is a hole in that portion of the image. Similarly, a short read for such an object indicates that the remainder of the read should be interpreted a full read with zeros filling out the end of the request. This behavior is not correct for objects that are not backing rbd image data. Currently rbd_img_obj_request_callback() assumes it should be done for all objects. Change rbd_img_obj_request_callback() so it only does this zeroing for image objects. Encapsulate that special handling in its own function. Add an assertion that the image object request is a bio request, since we assume that (and we currently don't support any other types). This resolves a problem identified here: http://tracker.ceph.com/issues/4559 The regression was introduced by bf0d5f503dc11d6314c0503591d258d60ee9c944. Reported-by: Dan van der Ster Signed-off-by: Alex Elder Reviewed-off-by: Sage Weil --- drivers/block/rbd.c | 47 ++++++++++++++++++++++++++++++----------------- 1 file changed, 30 insertions(+), 17 deletions(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 6c81a4c..f556f8a 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -1264,6 +1264,32 @@ static bool obj_request_done_test(struct rbd_obj_request *obj_request) return atomic_read(&obj_request->done) != 0; } +static void +rbd_img_obj_request_read_callback(struct rbd_obj_request *obj_request) +{ + dout("%s: obj %p img %p result %d %llu/%llu\n", __func__, + obj_request, obj_request->img_request, obj_request->result, + obj_request->xferred, obj_request->length); + /* + * ENOENT means a hole in the image. We zero-fill the + * entire length of the request. A short read also implies + * zero-fill to the end of the request. Either way we + * update the xferred count to indicate the whole request + * was satisfied. + */ + BUG_ON(obj_request->type != OBJ_REQUEST_BIO); + if (obj_request->result == -ENOENT) { + zero_bio_chain(obj_request->bio_list, 0); + obj_request->result = 0; + obj_request->xferred = obj_request->length; + } else if (obj_request->xferred < obj_request->length && + !obj_request->result) { + zero_bio_chain(obj_request->bio_list, obj_request->xferred); + obj_request->xferred = obj_request->length; + } + obj_request_done_set(obj_request); +} + static void rbd_obj_request_complete(struct rbd_obj_request *obj_request) { dout("%s: obj %p cb %p\n", __func__, obj_request, @@ -1284,23 +1310,10 @@ static void rbd_osd_read_callback(struct rbd_obj_request *obj_request) { dout("%s: obj %p result %d %llu/%llu\n", __func__, obj_request, obj_request->result, obj_request->xferred, obj_request->length); - /* - * ENOENT means a hole in the object. We zero-fill the - * entire length of the request. A short read also implies - * zero-fill to the end of the request. Either way we - * update the xferred count to indicate the whole request - * was satisfied. - */ - if (obj_request->result == -ENOENT) { - zero_bio_chain(obj_request->bio_list, 0); - obj_request->result = 0; - obj_request->xferred = obj_request->length; - } else if (obj_request->xferred < obj_request->length && - !obj_request->result) { - zero_bio_chain(obj_request->bio_list, obj_request->xferred); - obj_request->xferred = obj_request->length; - } - obj_request_done_set(obj_request); + if (obj_request->img_request) + rbd_img_obj_request_read_callback(obj_request); + else + obj_request_done_set(obj_request); } static void rbd_osd_write_callback(struct rbd_obj_request *obj_request) -- 2.7.4