(This patch is available in the branch "review/wip-4559" in the
ceph-client git repository.)
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).
Reported-by: Dan van der Ster <dan@xxxxxxxxxxxxxx>
Signed-off-by: Alex Elder <elder@xxxxxxxxxxx>
---
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 cc74b2c..d54a045 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)
--
1.7.9.5
--
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