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Date: Tue, 5 Dec 2023 22:38:12 -0800
From: Christoph Hellwig <hch@infradead.org>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-btrfs@vger.kernel.org, Josef Bacik <josef@toxicpanda.com>
Subject: Re: [PATCH] fscrypt: move the call to fscrypt_destroy_keyring() into
 ->put_super()
Message-ID: <ZXAW1BREPtCSUz4W@infradead.org>
References: <20231206001325.13676-1-ebiggers@kernel.org>
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On Tue, Dec 05, 2023 at 04:13:24PM -0800, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> btrfs, which is planning to add support for fscrypt, has a variety of
> asynchronous things it does with inodes that can potentially last until
> ->put_super, when it shuts everything down and cleans up all async work.
> Consequently, btrfs needs the call to fscrypt_destroy_keyring() to
> happen either after or within ->put_super.
> 
> Meanwhile, f2fs needs the call to fscrypt_destroy_keyring() to happen
> either *before* or within ->put_super, due to the dependency of
> f2fs_get_devices() on ->s_fs_info still existing.

And that means f2fs should free ->s_fs_info in ->kill_sb after
the call to shutdown_generic_super.

So the right thing here is:

 - change f2fs to free ->s_fs_info later
 - move down fscrypt_destroy_keyring in the keneric code to happen
   after ->put_super