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From:   Gabriel Krisman Bertazi <krisman@collabora.com>
To:     Daniel Rosenberg <drosen@google.com>
Cc:     "Theodore Y . Ts'o" <tytso@mit.edu>,
        Jaegeuk Kim <jaegeuk@kernel.org>,
        Eric Biggers <ebiggers@kernel.org>,
        Andreas Dilger <adilger.kernel@dilger.ca>,
        Chao Yu <chao@kernel.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Richard Weinberger <richard@nod.at>,
        linux-fscrypt@vger.kernel.org, linux-ext4@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-mtd@lists.infradead.org, kernel-team@android.com,
        Eric Biggers <ebiggers@google.com>
Subject: Re: [PATCH v4 1/3] libfs: Add generic function for setting dentry_ops
Organization: Collabora
References: <20201119060904.463807-1-drosen@google.com>
        <20201119060904.463807-2-drosen@google.com>
Date:   Sat, 21 Nov 2020 23:55:37 -0500
In-Reply-To: <20201119060904.463807-2-drosen@google.com> (Daniel Rosenberg's
        message of "Thu, 19 Nov 2020 06:09:02 +0000")
Message-ID: <87tutij8hi.fsf@collabora.com>
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Daniel Rosenberg <drosen@google.com> writes:

> This adds a function to set dentry operations at lookup time that will
> work for both encrypted filenames and casefolded filenames.
>
> A filesystem that supports both features simultaneously can use this
> function during lookup preparations to set up its dentry operations once
> fscrypt no longer does that itself.
>
> Currently the casefolding dentry operation are always set if the
> filesystem defines an encoding because the features is toggleable on
> empty directories. Unlike in the encryption case, the dentry operations
> used come from the parent. Since we don't know what set of functions
> we'll eventually need, and cannot change them later, we enable the
> casefolding operations if the filesystem supports them at all.
>
> By splitting out the various cases, we support as few dentry operations
> as we can get away with, maximizing compatibility with overlayfs, which
> will not function if a filesystem supports certain dentry_operations.
>
> Signed-off-by: Daniel Rosenberg <drosen@google.com>
> Reviewed-by: Eric Biggers <ebiggers@google.com>

Reviewed-by: Gabriel Krisman Bertazi <krisman@collabora.com>

-- 
Gabriel Krisman Bertazi