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From: Chao Yu <>
To: Daniel Rosenberg <>,
	Jaegeuk Kim <>, Chao Yu <>,
	Jonathan Corbet <>,
Subject: Re: [f2fs-dev] [PATCH v4 2/3] f2fs: include charset encoding information in the superblock
Date: Sun, 28 Jul 2019 08:45:51 +0800
Message-ID: <> (raw)
In-Reply-To: <>

On 2019-7-24 7:05, Daniel Rosenberg via Linux-f2fs-devel wrote:
> Add charset encoding to f2fs to support casefolding. It is modeled after
> the same feature introduced in commit c83ad55eaa91 ("ext4: include charset
> encoding information in the superblock")
> Currently this is not compatible with encryption, similar to the current
> ext4 imlpementation. This will change in the future.
> From the ext4 patch:
> """
> The s_encoding field stores a magic number indicating the encoding
> format and version used globally by file and directory names in the
> filesystem.  The s_encoding_flags defines policies for using the charset
> encoding, like how to handle invalid sequences.  The magic number is
> mapped to the exact charset table, but the mapping is specific to ext4.
> Since we don't have any commitment to support old encodings, the only
> encoding I am supporting right now is utf8-12.1.0.
> The current implementation prevents the user from enabling encoding and
> per-directory encryption on the same filesystem at the same time.  The
> incompatibility between these features lies in how we do efficient
> directory searches when we cannot be sure the encryption of the user
> provided fname will match the actual hash stored in the disk without
> decrypting every directory entry, because of normalization cases.  My
> quickest solution is to simply block the concurrent use of these
> features for now, and enable it later, once we have a better solution.
> """
> Signed-off-by: Daniel Rosenberg <>

Reviewed-by: Chao Yu <>


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Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-23 23:05 [f2fs-dev] [PATCH v4 0/3] Casefolding in F2FS Daniel Rosenberg via Linux-f2fs-devel
2019-07-23 23:05 ` [f2fs-dev] [PATCH v4 1/3] fs: Reserve flag for casefolding Daniel Rosenberg via Linux-f2fs-devel
2019-07-28  0:36   ` Chao Yu
2019-07-23 23:05 ` [f2fs-dev] [PATCH v4 2/3] f2fs: include charset encoding information in the superblock Daniel Rosenberg via Linux-f2fs-devel
2019-07-28  0:45   ` Chao Yu [this message]
2019-07-23 23:05 ` [f2fs-dev] [PATCH v4 3/3] f2fs: Support case-insensitive file name lookups Daniel Rosenberg via Linux-f2fs-devel
2019-07-28  0:55   ` Chao Yu
2019-07-29  6:27     ` Jaegeuk Kim
2019-07-29  7:22       ` Chao Yu
2019-07-29 14:57         ` Chao Yu
2019-07-31 17:57   ` Nathan Chancellor
2019-08-01  1:11     ` Chao Yu
2019-08-01  4:05       ` Jaegeuk Kim
2019-08-21 13:15   ` Chao Yu

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