GNU bug report logs - #9256
Erroneous output from "verify-visited-file-modtime" (fileio.c)

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Message #17 received at 9256-done <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Lars Ingebrigtsen <larsi <at> gnus.org>
Cc: Vivien Mallet <Vivien.Mallet <at> inria.fr>, 9256-done <at> debbugs.gnu.org
Subject: Re: Erroneous output from "verify-visited-file-modtime" (fileio.c)
Date: Mon, 20 Jan 2020 01:36:24 -0800

[Message part 1 (text/plain, inline)]

> I'd expect things to bug out pretty regularly across the board,
> since you'd have to check for EINTR in every single call to a bunch of
> system calls

Yes in theory. However, Emacs already does the EINTR check for open, read and 
write even on regular files where POSIX says it can't happen (but it does happen 
with NFS). If you've recently dealt with an NFS file then it'll be cached on the 
client and you won't get EINTR, so in practice the issue comes up only for 
syscalls that are applied to a file that hasn't been looked at lately. stat is 
one of these calls (hence the bug report) so we might as well do the EINTR check 
for it as well. I installed the attached patch to do that for stat and similar 
calls, and also for openat (which I think was overlooked when 'open' was done).

The other part of this bug report (with ENOENT) is not something Emacs can work 
around and it's surely a bug in the Linux NFS client that was most likely fixed 
a while ago anyway <https://bugzilla.kernel.org/show_bug.cgi?id=14541>.

As I think both issues in the bug report have been addressed, I'm boldly closing it.

[0001-Work-better-if-stat-etc.-are-interrupted.patch (text/x-patch, attachment)]

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