From: Daniel Rosenberg via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>
To: Eric Biggers <ebiggers@kernel.org>
Cc: kernel-team@android.com, Theodore Ts'o <tytso@mit.edu>,
Jonathan Corbet <corbet@lwn.net>,
Richard Weinberger <richard@nod.at>,
Andreas Dilger <adilger.kernel@dilger.ca>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net,
linux-fscrypt@vger.kernel.org, linux-mtd@lists.infradead.org,
Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, Jaegeuk Kim <jaegeuk@kernel.org>,
linux-ext4@vger.kernel.org,
Gabriel Krisman Bertazi <krisman@collabora.com>
Subject: Re: [f2fs-dev] [PATCH v9 2/4] fs: Add standard casefolding support
Date: Thu, 2 Jul 2020 18:01:37 -0700 [thread overview]
Message-ID: <CA+PiJmTDXTKnccJdADX=ir+PtqsDD72xHGbzObpntkjkVmKHxQ@mail.gmail.com> (raw)
In-Reply-To: <20200624055707.GG844@sol.localdomain>
On Tue, Jun 23, 2020 at 10:57 PM Eric Biggers <ebiggers@kernel.org> wrote:
>
> Note that the '!IS_ENCRYPTED(dir) || fscrypt_has_encryption_key(dir)' check can
> be racy, because a process can be looking up a no-key token in a directory while
> concurrently another process initializes the directory's ->i_crypt_info, causing
> fscrypt_has_encryption_key(dir) to suddenly start returning true.
>
> In my rework of filename handling in f2fs, I actually ended up removing all
> calls to needs_casefold(), thus avoiding this race. f2fs now decides whether
> the name is going to need casefolding early on, in __f2fs_setup_filename(),
> where it knows in a race-free way whether the filename is a no-key token or not.
>
> Perhaps ext4 should work the same way? It did look like there would be some
> extra complexity due to how the ext4 directory hashing works in comparison to
> f2fs's, but I haven't had a chance to properly investigate it.
>
> - Eric
Hm. I think I should be able to just check for DCACHE_ENCRYPTED_NAME
in the dentry here, right? I'm just trying to avoid casefolding the
no-key token, and that flag should indicate that.
I'll see if I can rework the ext4 patches to not need needs_casefold
as well, since then there'd be no need to export it.
-Daniel
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next prev parent reply other threads:[~2020-07-03 1:02 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-24 4:33 [f2fs-dev] [PATCH v9 0/4] Prepare for upcoming Casefolding/Encryption patches Daniel Rosenberg via Linux-f2fs-devel
2020-06-24 4:33 ` [f2fs-dev] [PATCH v9 1/4] unicode: Add utf8_casefold_hash Daniel Rosenberg via Linux-f2fs-devel
2020-06-24 5:13 ` Gabriel Krisman Bertazi
2020-06-24 5:37 ` Eric Biggers
2020-06-24 4:33 ` [f2fs-dev] [PATCH v9 2/4] fs: Add standard casefolding support Daniel Rosenberg via Linux-f2fs-devel
2020-06-24 5:33 ` Gabriel Krisman Bertazi
2020-06-24 5:42 ` Eric Biggers
2020-06-24 5:57 ` Eric Biggers
2020-07-03 1:01 ` Daniel Rosenberg via Linux-f2fs-devel [this message]
2020-07-03 19:20 ` Eric Biggers
2020-06-24 4:33 ` [f2fs-dev] [PATCH v9 3/4] f2fs: Use generic " Daniel Rosenberg via Linux-f2fs-devel
2020-06-24 4:33 ` [f2fs-dev] [PATCH v9 4/4] ext4: " Daniel Rosenberg via Linux-f2fs-devel
2020-06-24 5:43 ` Gabriel Krisman Bertazi
2020-07-07 10:44 ` Daniel Rosenberg via Linux-f2fs-devel
2020-06-24 6:04 ` Eric Biggers
2020-06-24 5:34 ` [f2fs-dev] [PATCH v9 0/4] Prepare for upcoming Casefolding/Encryption patches Eric Biggers
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