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From: Roman Mamedov <rm@romanrm.net>
To: Yuwei Han <hrx@bupt.moe>
Cc: dsterba@suse.cz, linux-btrfs@vger.kernel.org
Subject: Re: [RFC] New ioctl to query deleted subvolumes
Date: Fri, 11 Oct 2024 17:20:43 +0500	[thread overview]
Message-ID: <20241011172043.122e81ff@nvm> (raw)
In-Reply-To: <E2F46BD92527EA46+29cb502c-a5ee-48db-a439-ab692a3747b9@bupt.moe>

On Fri, 11 Oct 2024 20:06:00 +0800
Yuwei Han <hrx@bupt.moe> wrote:

> There is a misunderstanding. What I mean is that why users need to 
> "confirm" subvol is deleted? I can't come up with actual usage. Hope you 
> can help me with that.

A backup system may delete outdated subvolumes first, then wait until the
space has actually freed up, before copying new data; otherwise it could run
out of disk space. Especially considering that IO from starting to copy
without such a wait would interfere with the cleaner process IO, resulting in
it taking a longer time to finish.

Or in my case I also wait until deleted subvolumes have been freed up *after*
a backup, to then record how much remaining space a backup disk actually has,
before unmounting it and putting into storage.

-- 
With respect,
Roman

  reply	other threads:[~2024-10-11 12:27 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-09 18:03 [RFC] New ioctl to query deleted subvolumes David Sterba
2024-10-10 12:29 ` Yuwei Han
2024-10-10 17:08   ` David Sterba
2024-10-11 12:06     ` Yuwei Han
2024-10-11 12:20       ` Roman Mamedov [this message]
2024-10-12  1:45         ` Yuwei Han
2024-10-11 15:48       ` David Sterba

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