linux-kernel - Re: [PATCH v4 1/3] libfs: Add generic function for setting dentry

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Message-ID: <87tutij8hi.fsf@collabora.com>
Date:   Sat, 21 Nov 2020 23:55:37 -0500
From:   Gabriel Krisman Bertazi <krisman@...labora.com>
To:     Daniel Rosenberg <drosen@...gle.com>
Cc:     "Theodore Y . Ts'o" <tytso@....edu>,
        Jaegeuk Kim <jaegeuk@...nel.org>,
        Eric Biggers <ebiggers@...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, kernel-team@...roid.com,
        Eric Biggers <ebiggers@...gle.com>
Subject: Re: [PATCH v4 1/3] libfs: Add generic function for setting dentry_ops

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

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

-- 
Gabriel Krisman Bertazi