Re: PostgreSQL's handling of fsync() errors is unsafe and risks data loss at least on XFS

On Sat, Mar 31, 2018 at 12:38:12PM -0400, Tom Lane wrote:
> Craig Ringer <craig@2ndquadrant.com> writes:
> > So we should just use the big hammer here.
>
> And bitch, loudly and publicly, about how broken this kernel behavior is.
> If we make enough of a stink maybe it'll get fixed.

It is not likely to be fixed (beyond what has been done already with the
manpage patches and errseq_t fixes on the reporting level). The issue is,
the kernel needs to deal with hard IO errors at that level somehow, and
since those errors typically persist, re-dirtying the pages would not
really solve the problem (unless some filesystem remaps the request to a
different block, assuming the device is alive). Keeping around dirty
pages that cannot possibly be written out is essentially a memory leak,
as those pages would stay around even after the application has exited.

Best regards,
Anthony