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Date: Sat, 9 Dec 2023 13:29:38 -0800
From: Eric Biggers <ebiggers@kernel.org>
To: Christoph Hellwig <hch@infradead.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: <20231209212938.GA2270@sol.localdomain>
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 <ZXAW1BREPtCSUz4W@infradead.org>
 <20231206064430.GA41771@sol.localdomain>
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In-Reply-To: <ZXAf0WUbCccBn5QM@infradead.org>

On Tue, Dec 05, 2023 at 11:16:33PM -0800, Christoph Hellwig wrote:
> On Tue, Dec 05, 2023 at 10:44:30PM -0800, Eric Biggers wrote:
> > There are lots of filesystems that free their ->s_fs_info in ->put_super().  Are
> > they all wrong?
> 
> Wrong is the wrong word :)
> 
> For simple file systems that either don't use block devices, or just
> the main one set up by the super.c code using ->put_super is perfectly
> fine.  Once a file system does something complicated like setting up
> their own block devices, or trying to reuse super blocks using custom
> rules it basically has to free ->s_fs_info  in it's own ->kill_sb
> handler.  This whole area is a bit messy unfortunately.
> 

btrfs releases its block devices in ->put_super(), so with your proposal that
would need to be moved to ->kill_sb() as well, right?

I guess I'm a bit concerned about introducing a requirement "->put_super() must
not release the block devices" which seemingly didn't exist before.

- Eric