linux-ext4 - Re: [PATCH v3 3/3] f2fs: Handle casefolding with Encryption

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Message-ID: <X7Vwkgb8tqJh+mOr@sol.localdomain>
Date:   Wed, 18 Nov 2020 11:05:54 -0800
From:   Eric Biggers <ebiggers@...nel.org>
To:     Daniel Rosenberg <drosen@...gle.com>
Cc:     "Theodore Y . Ts'o" <tytso@....edu>,
        Jaegeuk Kim <jaegeuk@...nel.org>,
        Andreas Dilger <adilger.kernel@...ger.ca>,
        Chao Yu <chao@...nel.org>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Richard Weinberger <richard@....at>,
        linux-fscrypt@...r.kernel.org, linux-ext4@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-mtd@...ts.infradead.org,
        Gabriel Krisman Bertazi <krisman@...labora.com>,
        kernel-team@...roid.com
Subject: Re: [PATCH v3 3/3] f2fs: Handle casefolding with Encryption

On Wed, Nov 18, 2020 at 06:42:45AM +0000, Daniel Rosenberg wrote:
> Expand f2fs's casefolding support to include encrypted directories.  To
> index casefolded+encrypted directories, we use the SipHash of the
> casefolded name, keyed by a key derived from the directory's fscrypt
> master key.  This ensures that the dirhash doesn't leak information
> about the plaintext filenames.
> 
> Encryption keys are unavailable during roll-forward recovery, so we
> can't compute the dirhash when recovering a new dentry in an encrypted +
> casefolded directory.  To avoid having to force a checkpoint when a new
> file is fsync'ed, store the dirhash on-disk appended to i_name.
> 
> This patch incorporates work by Eric Biggers <ebiggers@...gle.com>
> and Jaegeuk Kim <jaegeuk@...nel.org>.
> 
> Co-developed-by: Eric Biggers <ebiggers@...gle.com>
> Signed-off-by: Eric Biggers <ebiggers@...gle.com>
> Signed-off-by: Daniel Rosenberg <drosen@...gle.com>

Looks good.  If it's needed (some may claim it's not needed because I have a
Co-developed-by), you can add:

	Reviewed-by: Eric Biggers <ebiggers@...gle.com>

- Eric