On Tue, Oct 03, 2023 at 09:44:50AM +0900, Damien Le Moal wrote: > Hmmm... So this could be the fs suspend then, which issues a sync but the device > is already suspended and was synced already. In that case, we should turn that > sync into a nop to not wakeup the drive unnecessarily. The fix may be needed on > scsi sd side rather than libata. I did some tracing today on a test ext4 fs I created on a loopback device, and it seems that the superblocks are written every time you sync, even if no files on the filesystem have even been opened for read access.