On Thu, Sep 17, 2020 at 01:28:29PM +0200, Ævar Arnfjörð Bjarmason wrote:

Change the behavior of core.fsyncObjectFiles to also sync the
directory entry. I don't have a case where this broke, just going by
paranoia and the fsync(2) manual page's guarantees about its behavior.

It is not just paranoia, but indeed what is required from the standards
POV.  At least for many Linux file systems your second fsync will be
very cheap (basically a NULL syscall) as the log has alredy been forced
all the way by the first one, but you can't rely on that.

Acked-by: Christoph Hellwig <hch@lst.de>