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Date:   Fri, 4 Jun 2021 14:58:45 -0400
From:   "Theodore Ts'o" <tytso@mit.edu>
To:     Jaegeuk Kim <jaegeuk@kernel.org>
Cc:     Eric Biggers <ebiggers@kernel.org>,
        Daniel Rosenberg <drosen@google.com>,
        Chao Yu <chao@kernel.org>,
        linux-f2fs-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        Gabriel Krisman Bertazi <krisman@collabora.com>,
        kernel-team@android.com, stable@vger.kernel.org
Subject: Re: [PATCH v2 2/2] f2fs: Advertise encrypted casefolding in sysfs
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On Thu, Jun 03, 2021 at 10:38:48PM -0700, Jaegeuk Kim wrote:
 > > Yes, but in the on-disk case, encrypted_casefold is redundant because it simply
> > means encrypt && casefold.  There is no encrypted_casefold flag on-disk.
> 
> I prefer to keep encrypted_casefold likewise kernel feature, which is more
> intuitive to users.

At least for ext4, there are kernel vesions which support encryption
and casefold *separetely*, but which do not support the file systems
that have encryption and casefold enabled simultaneously.  This is why
I had added /sys/fs/ext4/features/encrypted_casefold.  It was
originally not to indicate whether the on-disk file system supported
those features, but to indicate that the kernel in question supported
both features being enabled simultaneously.

					- Ted