Hello, I'm digging way back here - in https://tracker.ceph.com/issues/12405#note-12, Sage said:

2017-11-29 Newer kernels fix syncfs(2) to use a dirty inode list for this. (The fix isn't in the latest el7 kernel(s) yet, though.)

Try as I might, I can't seem to narrow down which upstream kernel version gained this improvement. Any chance that someone remembers? Thanks! Josh