Rethinking multi-grain timestamps
Rethinking multi-grain timestamps
Posted Oct 9, 2023 15:55 UTC (Mon) by tux3 (subscriber, #101245)Parent article: Rethinking multi-grain timestamps
>Timestamps are carefully truncated before being reported to user space, though, so that the higher resolution is not visible outside of the virtual filesystem layer. That should prevent problems like the one described above.
I may be confused, but is it really enough?
Say I write file 1 from userspace, locally, I do steps 2, 3, 4 on file 2 from NFS.
Now, a local program watches file 2, sees that it has been written, and responds by updating write file 1 (locally).
On the other side of the NFS, maybe I am waiting to see a file 1 update, because I expect the watcher program to respond.
Can it happen that I see file 1 written before file 2, because file 1 got a low-res timestamp, but NFS still returns me a high-resolution file 2 timestamp, and so I wait forever?