Date: Fri, 22 Feb 2019 14:28:46 -0800
From: Andres Freund <andres@anarazel.de>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: John Klann <jk7255@gmail.com>, Stephen Frost <sfrost@snowman.net>,
	PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Subject: Re: BUG #15636: PostgreSQL 11.1 pg_basebackup backup to a CIFS
 destination throws fsync error at end of backup
Message-ID: <20190222222846.fgxnu754kuvcwxia@alap3.anarazel.de>
References: <15636-d380890dafd78fc6@postgresql.org>
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Hi,

On 2019-02-23 11:20:02 +1300, Thomas Munro wrote:
> So, for this patch tolerating EINVAL for fsync of directories (but not
> files), enabling eg pg_backbackup on CIFS on eg Linux 3.10 to work,
> tested by John, we have:
> 
> Stephen: +1
> Michael: -0.1
> Thomas: -0.1
> 
> Any other opinions?
> 
> Just in case you think it's strange that I'm voting against my own
> patch: I'd probably be for it if I hadn't discovered that they've
> fixed this in Linux 3.16 and later so that it succeeds.  It's
> apparently not in the default RHEL 6 and 7 kernels, though, and the
> latter could be around for a while.  I'm not entirely sure what amount
> of work we should be doing to tolerate problems that are fixed in a
> newer versions.  One argument is that a 3.10 user who cares about this
> should petition RH to back-port the fix into that kernel.  (The nearby
> WSL thread has some things in common but is a more clear cut case IMV
> because there is no fix available on the WSL side.)

Hm, given the fact that EINVAL doesn't appear to be triggerable by data
level issues, I don't see much reason not to allow it. I mean it's
really stupid that cifs ever returns it, but there's going to be a lot
of users running things on older kernel for the forseeable future.

Greetings,

Andres Freund