rbd: don't revalidate so much (a3fbe5d4) · Commits · 戴 / test

Whenever a header object event causes a mapped rbd image to refresh its header information, revalidate_disk() is being called. This was done in rbd_dev_refresh() outside the control mutex in order to avoid a lock inversion. Although a an event like this *might* indicate the image has changed size, most of the time it does not. Record the image size before and after the refresh, and only call revalidate_disk() if it changes. This resolves: http://tracker.ceph.com/issues/4867 Signed-off-by:

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

Josh Durgin <josh.durgin@inktank.com>

drivers/block/rbd.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -3065,19 +3065,22 @@ static int rbd_dev_v1_refresh(struct rbd_device rbd_dev, u64 hver)

		static int rbd_dev_refresh(struct rbd_device rbd_dev, u64 hver)
		{
		u64 image_size;
		int ret;

		rbd_assert(rbd_image_format_valid(rbd_dev->image_format));
		image_size = rbd_dev->header.image_size;
		mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
		if (rbd_dev->image_format == 1)
		ret = rbd_dev_v1_refresh(rbd_dev, hver);
		else
		ret = rbd_dev_v2_refresh(rbd_dev, hver);
		mutex_unlock(&ctl_mutex);
		revalidate_disk(rbd_dev->disk);
		if (ret)
		rbd_warn(rbd_dev, "got notification but failed to "
		" update snaps: %d\n", ret);
		if (image_size != rbd_dev->header.image_size)
		revalidate_disk(rbd_dev->disk);

		return ret;
		}

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