With read-after-open being set to yes by default, if open-behind sees any reads, it'll do an open on backend (and hence flush/release later). This means with the current order of quick-read and open-behind, open-behind sees all reads and hence also does open bringing down performance for small file reads. Since for small files, reads are absorbed by quick-read, if quick-read is made a parent of open-behind, ob doesn't witness any reads. For read-only workloads, this means ob doen't do any opens (even with read-after-open yes and use-anonymous-fd no). Change-Id: I138a42b006d104cff43ee6f07829e39c36f6f234 Signed-off-by: Raghavendra Gowdappa <rgowdapp@redhat.com> Fixes: bz#1659327