linux-kernel - Re: [regression] getdents() does not list entries created after opening the directory

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Message-ID: <b77aa757-4ea2-4c0a-8ba9-3685f944aa34@leemhuis.info>
Date: Tue, 1 Oct 2024 14:49:51 +0200
From: "Linux regression tracking (Thorsten Leemhuis)"
 <regressions@...mhuis.info>
To: Krzysztof Małysa <varqox@...il.com>
Cc: yangerkun <yangerkun@...wei.com>, Christian Brauner <brauner@...nel.org>,
 linux-fsdevel@...r.kernel.org, Alexander Viro <viro@...iv.linux.org.uk>,
 LKML <linux-kernel@...r.kernel.org>, Matthew Wilcox <willy@...radead.org>,
 Linux regressions mailing list <regressions@...ts.linux.dev>
Subject: Re: [regression] getdents() does not list entries created after
 opening the directory

On 01.10.24 14:18, Matthew Wilcox wrote:
> On Tue, Oct 01, 2024 at 01:29:09PM +0200, Linux regression tracking (Thorsten Leemhuis) wrote:
>>> 	DIR* dir = opendir("/tmp/dirent-problems-test-dir");
>>>
>>> 	fd = creat("/tmp/dirent-problems-test-dir/after", 0644);
> 
> "If a file is removed from or added to the directory after the most
> recent call to opendir() or rewinddir(), whether a subsequent call to
> readdir() returns an entry for that file is unspecified."
> 
> https://pubs.opengroup.org/onlinepubs/007904975/functions/readdir.html
> 
> That said, if there's an easy fix here, it'd be a nice improvement to
> QoI to do it, but the test-case as written is incorrect.

Many thx Willy!

Which leads to a question:

Krzysztof, how did you find the problem? Was there a practical use case
(some software or workload) with this behavior that broke and made your
write that test-case? Or is that a test-program older and part of your
CI tests or something like that?

Ciao, Thorsten