From patchwork Tue Sep 6 00:35:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sweet Tea Dorminy X-Patchwork-Id: 12966691 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A7A2C6FA86 for ; Tue, 6 Sep 2022 00:36:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236506AbiIFAgS (ORCPT ); Mon, 5 Sep 2022 20:36:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40252 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232772AbiIFAgP (ORCPT ); Mon, 5 Sep 2022 20:36:15 -0400 Received: from box.fidei.email (box.fidei.email [71.19.144.250]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC9616A4A8; Mon, 5 Sep 2022 17:36:11 -0700 (PDT) Received: from authenticated-user (box.fidei.email [71.19.144.250]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by box.fidei.email (Postfix) with ESMTPSA id 60AC781158; Mon, 5 Sep 2022 20:36:11 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1662424571; bh=qs/PbHgqpvuCxRL5lwfqdPPBlbi/vM+biDOAKHz7sn4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DKzy3x6o+19lIA+lYi8qQtQWOXgfDwFIZp+PTVQcddHbhFXfDb9tjGVUFUYhG4ww7 t7jDBHz8tEYBzRb+0yGI7IIvMoI8K+7x1nz13/RZGTGUNurqMn6spgtbYGPG041bLZ V8zeW78NVqRgzL7Iho7+zDrWhtiEidCnD7tT7aFoSilNP4RBWIcpkmRml0plSbUg0C aPj/OxYQqbSSDOCTnWVf/WxRPW6cdnx/whv+Sbv427Q0DLOeS68dCDV2yadkKxJBTV Y/Ncg+PYzmXacbiCKc3zZNV5Rt3Gwu66fAsIV4ZKbjbRqkSrqfY31oWHtr0MT4Hyxn qAxh/HzLaZh/Q== From: Sweet Tea Dorminy To: "Theodore Y. Ts'o" , Jaegeuk Kim , Eric Biggers , Chris Mason , Josef Bacik , David Sterba , linux-fscrypt@vger.kernel.org, linux-btrfs@vger.kernel.org, kernel-team@fb.com Cc: Omar Sandoval , Sweet Tea Dorminy Subject: [PATCH v2 17/20] btrfs: reuse encrypted filename hash when possible. Date: Mon, 5 Sep 2022 20:35:32 -0400 Message-Id: In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Omar Sandoval For encrypted fscrypt_names, we can reuse fscrypt's precomputed hash of the encrypted name to generate our own hash, instead of rehashing the unencrypted name (which may not be possible if it's a nokey name). Signed-off-by: Omar Sandoval Signed-off-by: Sweet Tea Dorminy --- fs/btrfs/ctree.h | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index e8d000fcc85d..aa599518c057 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2842,7 +2842,10 @@ static inline void btrfs_crc32c_final(u32 crc, u8 *result) static inline u64 btrfs_name_hash(const struct fscrypt_name *name) { - return crc32c((u32)~1, fname_name(name), fname_len(name)); + if (fname_name(name)) + return crc32c((u32)~1, fname_name(name), fname_len(name)); + else + return name->hash | ((u64)name->minor_hash << 32); } /* @@ -2851,8 +2854,20 @@ static inline u64 btrfs_name_hash(const struct fscrypt_name *name) static inline u64 btrfs_extref_hash(u64 parent_objectid, const struct fscrypt_name *name) { - return (u64) crc32c(parent_objectid, fname_name(name), - fname_len(name)); + /* + * If the name is encrypted and we don't have the key, we can use the + * fscrypt-provided hash instead of the normal name, and do the steps + * of crc32c() manually. Else, just hash the name, parent objectid, + * and name length. + */ + if (fname_name(name)) + return (u64) crc32c(parent_objectid, fname_name(name), + fname_len(name)); + else + return (__crc32c_le_combine(parent_objectid, + name->hash, + fname_len(name)) ^ + __crc32c_le_shift(~1, fname_len(name))); } static inline gfp_t btrfs_alloc_write_mask(struct address_space *mapping)