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Date:   Tue, 5 Nov 2019 22:26:20 -0500
From:   "Theodore Y. Ts'o" <tytso@mit.edu>
To:     Eric Biggers <ebiggers@kernel.org>
Cc:     linux-fscrypt@vger.kernel.org, linux-ext4@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net,
        linux-fsdevel@vger.kernel.org, Satya Tangirala <satyat@google.com>,
        Paul Crowley <paulcrowley@google.com>,
        Paul Lawrence <paullawrence@google.com>,
        Jaegeuk Kim <jaegeuk@kernel.org>
Subject: Re: [PATCH v2 2/3] ext4: add support for IV_INO_LBLK_64 encryption
 policies
Message-ID: <20191106032620.GF26959@mit.edu>
References: <20191024215438.138489-1-ebiggers@kernel.org>
 <20191024215438.138489-3-ebiggers@kernel.org>
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On Thu, Oct 24, 2019 at 02:54:37PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> IV_INO_LBLK_64 encryption policies have special requirements from the
> filesystem beyond those of the existing encryption policies:
> 
> - Inode numbers must never change, even if the filesystem is resized.
> - Inode numbers must be <= 32 bits.
> - File logical block numbers must be <= 32 bits.
> 
> ext4 has 32-bit inode and file logical block numbers.  However,
> resize2fs can re-number inodes when shrinking an ext4 filesystem.
> 
> However, typically the people who would want to use this format don't
> care about filesystem shrinking.  They'd be fine with a solution that
> just prevents the filesystem from being shrunk.
> 
> Therefore, add a new feature flag EXT4_FEATURE_COMPAT_STABLE_INODES that
> will do exactly that.  Then wire up the fscrypt_operations to expose
> this flag to fs/crypto/, so that it allows IV_INO_LBLK_64 policies when
> this flag is set.
>
> Signed-off-by: Eric Biggers <ebiggers@google.com>

LGTM

Acked-by: Theodore Ts'o <tytso@mit.edu>

						- Ted