rbd: stop tracking header object version (b21ebddd) · Commits · 戴 / test

The rbd code takes care to maintain the version of the header object. This was done in hopes of using it to detect a change in the object between reading it and setting up a watch request to be notified of changes. The mechanism was never fully implemented, however. And we now avoid the original problem by setting up the watch request before ever reading the content of the header. The osd doesn't interpret the object version supplied with a WATCH osd op, nor does it use the version supplied with a NOTIFY_ACK op (we can just supply 0 for both). There is therefore no need to maintain the header's object version any more, so stop doing so. We'll be able to simplify some more rbd code in the next few patches as a result of this. This resolves: http://tracker.ceph.com/issues/3952 Signed-off-by:

Alex Elder <elder@inktank.com> Reviewed-by:

Josh Durgin <josh.durgin@inktank.com>

drivers/block/rbd.c

+1 −10

Original line number	Diff line number	Diff line
		@@ -110,8 +110,6 @@ struct rbd_image_header {

		u64 stripe_unit;
		u64 stripe_count;

		u64 obj_version;
		};

		/*
		@@ -2554,8 +2552,7 @@ static int rbd_dev_header_watch_sync(struct rbd_device *rbd_dev, int start)
		rbd_dev->watch_request->osd_req);

		osd_req_op_watch_init(obj_request->osd_req, 0, CEPH_OSD_OP_WATCH,
		rbd_dev->watch_event->cookie,
		rbd_dev->header.obj_version, start);
		rbd_dev->watch_event->cookie, 0, start);
		rbd_osd_req_format_write(obj_request);

		ret = rbd_obj_request_submit(osdc, obj_request);
		@@ -2987,8 +2984,6 @@ static int rbd_read_header(struct rbd_device *rbd_dev,
		if (IS_ERR(ondisk))
		return PTR_ERR(ondisk);
		ret = rbd_header_from_disk(header, ondisk);
		if (ret >= 0)
		header->obj_version = ver;
		kfree(ondisk);

		return ret;
		@@ -3044,9 +3039,6 @@ static int rbd_dev_v1_refresh(struct rbd_device rbd_dev, u64 hver)
		/* osd requests may still refer to snapc */
		ceph_put_snap_context(rbd_dev->header.snapc);

		if (hver)
		*hver = h.obj_version;
		rbd_dev->header.obj_version = h.obj_version;
		rbd_dev->header.image_size = h.image_size;
		rbd_dev->header.snapc = h.snapc;
		rbd_dev->header.snap_names = h.snap_names;
		@@ -4656,7 +4648,6 @@ static int rbd_dev_v2_probe(struct rbd_device *rbd_dev)
		ret = rbd_dev_v2_snap_context(rbd_dev, &ver);
		if (ret)
		goto out_err;
		rbd_dev->header.obj_version = ver;

		dout("discovered version 2 image, header name is %s\n",
		rbd_dev->header_name);

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