linux-kernel - Re: Directory is not persisted after writing to the file within directory if system crashes

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Message-Id: <601d70f3-ab6d-4f15-88eb-169fede1a685@app.fastmail.com>
Date: Sat, 25 Oct 2025 19:40:54 -0400
From: "Chris Murphy" <lists@...orremedies.com>
To: "Vyacheslav Kovalevsky" <slava.kovalevskiy.2014@...il.com>,
 "Filipe Manana" <fdmanana@...nel.org>
Cc: "Chris Mason" <clm@...com>, "David Sterba" <dsterba@...e.com>,
 "Btrfs BTRFS" <linux-btrfs@...r.kernel.org>,
 linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: Directory is not persisted after writing to the file within directory if
 system crashes



On Sat, Oct 25, 2025, at 5:49 AM, Vyacheslav Kovalevsky wrote:
> I think the line with `echo` may not be the correct translation:
>  > echo -n "hello world" > $SCRATCH_MNT/file1
>
> In the original test, the file was opened with `O_SYNC` flag, if you 
> remove it, the directory will be there when the system crashes. I also 
> forgot to close the file after the `creat` call in the original test, 
> may be important as well.
>
> The test itself is quite weird (why would `dir` be gone after seemingly 
> unrelated operation?), any detail can matter.
>
> Please run the original test with a real system crash. 

This would produce hardware specific results rather than determining whether the file system is behaving correctly. It's possible the hardware is acknowledging the metadata, flush, super, flush, but then it's still not really persisting on disk


-- 
Chris Murphy