linux-ext4 - A possible way to reduce free space fragmentation?

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Message-ID: <8dcf1b6e-633c-4415-9412-6876efc07b50@gmx.com>
Date: Fri, 31 Jan 2025 19:01:56 +0000
From: "Artem S. Tashkinov" <aros@....com>
To: linux-ext4@...r.kernel.org
Subject: A possible way to reduce free space fragmentation?

Hello,

ext4 has no free space defragmentation and at most you can use e4defrag
to defragment individual files. I now have a 24GB ext4 filesystem that
has only 7GB of space occupied however it has small files scattered all
over it and now bigger files occupy more than one extent and I cannot
reduce fragmentation to zero. One way to approach that would be to
shrink the volume and then defragment it but that will involve a ton of
disk writes and unnecessary tear and wear. Is it possible to modify the
e4degrag utility to move small defragmented files, so that they were
placed consecutively instead of being randomly spread all over the disk?

Regards,
Artem