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Commit a3fbe5d4 authored by Alex Elder's avatar Alex Elder Committed by Sage Weil
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rbd: don't revalidate so much 

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: default avatarAlex Elder <elder@inktank.com>
Reviewed-by: default avatarJosh Durgin <josh.durgin@inktank.com>
parent 96882f55

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;

}