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Date:   Sat, 12 Aug 2023 15:43:01 -0700
From:   Eric Biggers <ebiggers@kernel.org>
To:     Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc:     Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
        David Sterba <dsterba@suse.com>,
        "Theodore Y . Ts'o" <tytso@mit.edu>,
        Jaegeuk Kim <jaegeuk@kernel.org>, kernel-team@meta.com,
        linux-btrfs@vger.kernel.org, linux-fscrypt@vger.kernel.org
Subject: Re: [PATCH v3 15/16] fscrypt: allow asynchronous info freeing
Message-ID: <20230812224301.GC41642@sol.localdomain>
References: <cover.1691505882.git.sweettea-kernel@dorminy.me>
 <6c4a29fdfabf90f1a43dffff04debd54f941cf93.1691505882.git.sweettea-kernel@dorminy.me>
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On Tue, Aug 08, 2023 at 01:08:32PM -0400, Sweet Tea Dorminy wrote:
> btrfs sometimes frees extents while holding a mutex. This makes it hard
> to free the prepared keys associated therewith, as the free process may
> need to take a semaphore. Just offloading freeing to rcu doesn't work,
> as rcu may call the callback in softirq context, which also doesn't
> allow taking a semaphore. Thus, for extent infos, offload their freeing
> to the general system workqueue.
> 
> Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>

Please be specific about which mutex and which semaphore.

What is the specific problem?

- Eric