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authorAlex Elder <elder@inktank.com>2013-05-06 17:40:33 -0500
committerAlex Elder <elder@inktank.com>2013-05-13 15:06:45 -0500
commit02c74fbad9d4a5149756eb35be7300736e4904e9 (patch)
tree927c54fd4815af9d7fa5d10100618febe6f87642
parent392a9dad7e777296fe79d97a6b3acd735ad2eb5f (diff)
downloadblackbird-op-linux-02c74fbad9d4a5149756eb35be7300736e4904e9.tar.gz
blackbird-op-linux-02c74fbad9d4a5149756eb35be7300736e4904e9.zip
rbd: re-submit read request for flattened clone
If a clone image gets flattened while a parent read request is underway, the original rbd object request needs to be resubmitted. The reason is that by the time we get the response to the parent read request, the data read from the parent may be out of date. In other words, we could see this sequence of events: rbd client parent image/osd ---------- ---------------- original object ENOENT; issue parent read respond to parent read child image flattened original image header refresh <--- original object written independently here parent read response received Add code to rbd_img_parent_read_callback() to detect when a clone's parent image has disappeared (as evidenced by its parent overlap becoming 0), and re-submit the original read request in that case. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
-rw-r--r--drivers/block/rbd.c30
1 files changed, 25 insertions, 5 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 9717e20f3477..4edcb6d85f01 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2682,14 +2682,36 @@ static void rbd_img_parent_read_callback(struct rbd_img_request *img_request)
struct rbd_obj_request *obj_request;
struct rbd_device *rbd_dev;
u64 obj_end;
+ u64 img_xferred;
+ int img_result;
rbd_assert(img_request_child_test(img_request));
+ /* First get what we need from the image request and release it */
+
obj_request = img_request->obj_request;
+ img_xferred = img_request->xferred;
+ img_result = img_request->result;
+ rbd_img_request_put(img_request);
+
+ /*
+ * If the overlap has become 0 (most likely because the
+ * image has been flattened) we need to re-submit the
+ * original request.
+ */
rbd_assert(obj_request);
rbd_assert(obj_request->img_request);
+ rbd_dev = obj_request->img_request->rbd_dev;
+ if (!rbd_dev->parent_overlap) {
+ struct ceph_osd_client *osdc;
+
+ osdc = &rbd_dev->rbd_client->client->osdc;
+ img_result = rbd_obj_request_submit(osdc, obj_request);
+ if (!img_result)
+ return;
+ }
- obj_request->result = img_request->result;
+ obj_request->result = img_result;
if (obj_request->result)
goto out;
@@ -2702,7 +2724,6 @@ static void rbd_img_parent_read_callback(struct rbd_img_request *img_request)
*/
rbd_assert(obj_request->img_offset < U64_MAX - obj_request->length);
obj_end = obj_request->img_offset + obj_request->length;
- rbd_dev = obj_request->img_request->rbd_dev;
if (obj_end > rbd_dev->parent_overlap) {
u64 xferred = 0;
@@ -2710,12 +2731,11 @@ static void rbd_img_parent_read_callback(struct rbd_img_request *img_request)
xferred = rbd_dev->parent_overlap -
obj_request->img_offset;
- obj_request->xferred = min(img_request->xferred, xferred);
+ obj_request->xferred = min(img_xferred, xferred);
} else {
- obj_request->xferred = img_request->xferred;
+ obj_request->xferred = img_xferred;
}
out:
- rbd_img_request_put(img_request);
rbd_img_obj_request_read_callback(obj_request);
rbd_obj_request_complete(obj_request);
}
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