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: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 71e2de2..ab2c788 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3065,19 +3065,22 @@
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;
}