From: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
To: fdmanana@kernel.org, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 1/2] btrfs: fix data races when accessing the reserved amount of block reserves
Date: Mon, 26 Feb 2024 12:39:35 -0500 [thread overview]
Message-ID: <cf24775e-a9da-498e-93c6-8a2c8009f53a@dorminy.me> (raw)
In-Reply-To: <5ff1a68f4289d5bb870a499b248d329893d417ae.1708429856.git.fdmanana@suse.com>
> So add a helper to get the reserved amount of a block reserve while
> holding the lock. The value may be not be up to date anymore when used by
> need_preemptive_reclaim() and btrfs_preempt_reclaim_metadata_space(), but
> that's ok since the worst it can do is cause more reclaim work do be done
> sooner rather than later. Reading the field while holding the lock instead
> of using the data_race() annotation is used in order to prevent load
> tearing.
Would READ_ONCE() be enough? My understanding is that it should be
enough against load tearing if it's aligned, and I think both size and
reserved are aligned? But I'm always learning more about how to do
things right.
next prev parent reply other threads:[~2024-02-26 17:39 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-20 12:24 [PATCH 0/2] btrfs: fix a couple KCSAN warnings fdmanana
2024-02-20 12:24 ` [PATCH 1/2] btrfs: fix data races when accessing the reserved amount of block reserves fdmanana
2024-02-26 17:39 ` Sweet Tea Dorminy [this message]
2024-02-26 17:55 ` Filipe Manana
2024-02-20 12:24 ` [PATCH 2/2] btrfs: fix data race at btrfs_use_block_rsv() when accessing block reserve fdmanana
2024-02-21 11:12 ` [PATCH 0/2] btrfs: fix a couple KCSAN warnings David Sterba
2024-02-21 11:25 ` Filipe Manana
2024-02-21 11:31 ` David Sterba
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