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	Tue, 11 Mar 2025 04:56:35 +0000
Date: Tue, 11 Mar 2025 04:56:35 +0000
From: Al Viro <viro@zeniv.linux.org.uk>
To: Theodore Ts'o <tytso@mit.edu>
Cc: David Laight <david.laight.linux@gmail.com>,
	"Artem S. Tashkinov" <aros@gmx.com>, linux-ext4@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: A syscall for changing birth time
Message-ID: <20250311045635.GP2023217@ZenIV>
References: <bda3fa3f-dd12-40de-841a-e4c216ab533f@gmx.com>
 <20250310135828.GB8837@mit.edu>
 <20250310221243.0d5db7b3@pumpkin>
 <20250311044935.GD69932@mit.edu>
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Sender: Al Viro <viro@ftp.linux.org.uk>

On Tue, Mar 11, 2025 at 12:49:35AM -0400, Theodore Ts'o wrote:

> This really goes to my question of exactly how useful the file
> creation time concept really is.  Perhaps that's why the developers at
> the UC Berkley made ctime be "inode change time", I suspect when they
> authored the BSD Fast File System 42 years ago.  Personally, while I
> don't find "change time" to be all that useful --- I find "creation
> time" an order of magnitude *more* useless.  :-)

The third timestamp had been introduced in v7 and it had been "change
time" from the very beginning, with incremental backups as stated
rationale in filesys(5).  "I'm sure that" from David means "I couldn't
be arsed to check my WAG"...