On 10/4/23 06:22, Phillip Susi wrote: > 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. OK. So a fix would need to be on the FS side then if one wants to avoid that useless resume. However, this may clash with the FS need to record stuff in its sb and so we may not be able to avoid that. -- Damien Le Moal Western Digital Research