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

On Thu, Mar 29, 2018 at 3:30 PM, Michael Paquier <michael@paquier.xyz> wrote:
> On Tue, Mar 27, 2018 at 11:53:08PM -0400, Tom Lane wrote:
>> Craig Ringer <craig@2ndquadrant.com> writes:
>>> TL;DR: Pg should PANIC on fsync() EIO return.
>>
>> Surely you jest.
>
> Any callers of pg_fsync in the backend code are careful enough to check
> the returned status, sometimes doing retries like in mdsync, so what is
> proposed here would be a regression.

Craig, is the phenomenon you described the same as the second issue
"Reporting writeback errors" discussed in this article?

https://lwn.net/Articles/724307/

"Current kernels might report a writeback error on an fsync() call,
but there are a number of ways in which that can fail to happen."

That's... I'm speechless.

-- 
Thomas Munro
http://www.enterprisedb.com