From patchwork Fri Jun 4 21:09:02 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Satya Tangirala X-Patchwork-Id: 12300725 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C121AC4743E for ; Fri, 4 Jun 2021 21:09:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ACEAD613F4 for ; Fri, 4 Jun 2021 21:09:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230161AbhFDVLE (ORCPT ); Fri, 4 Jun 2021 17:11:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51154 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230208AbhFDVLD (ORCPT ); Fri, 4 Jun 2021 17:11:03 -0400 Received: from mail-pj1-x104a.google.com (mail-pj1-x104a.google.com [IPv6:2607:f8b0:4864:20::104a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0DF4EC061766 for ; Fri, 4 Jun 2021 14:09:17 -0700 (PDT) Received: by mail-pj1-x104a.google.com with SMTP id s5-20020a17090a7645b029016d923cccbeso936988pjl.0 for ; Fri, 04 Jun 2021 14:09:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=56OloOiE27JD9XtSi9HokxC2e9KDiOeAmTHFCwPKpyA=; b=vbqS3zJ19To/jom+ObfOanT8EILqfeS29IQIUOHVCS13utK55kbwH+b+vma82AiCBJ xJmQBnzp58GRQH/SF4e6+f/N45nMsWR3k1Me5k2EQOFH979IVe7QbUdKtS8q9A4uA7nK cOYRuyuZA0iSenAhsrYh0pKnkNdH/YcyBYbm0dmNAhFKShttIqf4FggtsjKcIY1/VN7i JvPgLgAsI3GUGhZ14x/DaOjeVUGHCCn9DSbfuZ2ZzKSNBxmAMxBuUSJacpNoHPPyza3+ OSlonI2XsmDcTAWVxMoffEB/jJUCvZ2KGqXueGuy2OK8JkJz0tfcPa4IzqhvW79Hwup/ 1OEQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=56OloOiE27JD9XtSi9HokxC2e9KDiOeAmTHFCwPKpyA=; b=Dwvgbx66qFQHfsaYyVjkMAjvXVq1TR8F50XmJsaRaP6XBTJW0GGs5zOR1cwYBAqk4T HuaXGbelG8jZJeizNZfo4OiHJnLeVdss/XgIh7TXKcUwD273if0DDqJCYaPoqK8cGrCB Tbv3hAXse53YzPWGmKxM8oAPpmHRvwn2D6V02iX3Ov8/CBcYJFyJ4YGX5Lbr9nC9sDwO OYMaT61quAbNFmn0YQomxS4KJv6VR+CogcuQKUqnd+ZGRlVWcs4oiLNCQ+yutS89vMpT CFneJZG3Xnr/YT536No0uNDUS09xxAj/3TdKphJgOsVt/evHgUWadCvuH7iVsn3cXOt0 Dg0Q== X-Gm-Message-State: AOAM532iHUIZdyV8bchGeLu6qRmaca/cDEzF2O7ZEkVJXgWdQvwbyreC ub5unKEe2sQXL1FnopIKt6uwiPojLsA= X-Google-Smtp-Source: ABdhPJzc2nffU5Z54IaqxPBWN/qr29mQecS8KOrrMRqa4DEUMTWf/BcnirC+grt57kCFTPNFLENEAXhle28= X-Received: from satyaprateek.c.googlers.com ([fda3:e722:ac3:10:24:72f4:c0a8:1092]) (user=satyat job=sendgmr) by 2002:a17:90a:db0f:: with SMTP id g15mr7943874pjv.156.1622840956608; Fri, 04 Jun 2021 14:09:16 -0700 (PDT) Date: Fri, 4 Jun 2021 21:09:02 +0000 In-Reply-To: <20210604210908.2105870-1-satyat@google.com> Message-Id: <20210604210908.2105870-4-satyat@google.com> Mime-Version: 1.0 References: <20210604210908.2105870-1-satyat@google.com> X-Mailer: git-send-email 2.32.0.rc1.229.g3e70b5a671-goog Subject: [PATCH v9 3/9] fscrypt: add functions for direct I/O support From: Satya Tangirala To: "Theodore Y . Ts'o" , Jaegeuk Kim , Eric Biggers , Chao Yu , Jens Axboe , "Darrick J . Wong" Cc: linux-kernel@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, linux-block@vger.kernel.org, linux-ext4@vger.kernel.org, Eric Biggers , Satya Tangirala Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Eric Biggers Introduce fscrypt_dio_supported() to check whether a direct I/O request is unsupported due to encryption constraints. Also introduce fscrypt_limit_io_blocks() to limit how many blocks can be added to a bio being prepared for direct I/O. This is needed for filesystems that use the iomap direct I/O implementation to avoid DUN wraparound in the middle of a bio (which is possible with the IV_INO_LBLK_32 IV generation method). Elsewhere fscrypt_mergeable_bio() is used for this, but iomap operates on logical ranges directly, so filesystems using iomap won't have a chance to call fscrypt_mergeable_bio() on every block added to a bio. So we need this function which limits a logical range in one go. Signed-off-by: Eric Biggers Co-developed-by: Satya Tangirala Signed-off-by: Satya Tangirala --- fs/crypto/crypto.c | 8 +++++ fs/crypto/inline_crypt.c | 75 ++++++++++++++++++++++++++++++++++++++++ include/linux/fscrypt.h | 18 ++++++++++ 3 files changed, 101 insertions(+) diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c index 4ef3f714046a..4fcca79f39ae 100644 --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -69,6 +69,14 @@ void fscrypt_free_bounce_page(struct page *bounce_page) } EXPORT_SYMBOL(fscrypt_free_bounce_page); +/* + * Generate the IV for the given logical block number within the given file. + * For filenames encryption, lblk_num == 0. + * + * Keep this in sync with fscrypt_limit_io_blocks(). fscrypt_limit_io_blocks() + * needs to know about any IV generation methods where the low bits of IV don't + * simply contain the lblk_num (e.g., IV_INO_LBLK_32). + */ void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num, const struct fscrypt_info *ci) { diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c index c57bebfa48fe..a7ce650fbd3b 100644 --- a/fs/crypto/inline_crypt.c +++ b/fs/crypto/inline_crypt.c @@ -17,6 +17,7 @@ #include #include #include +#include #include "fscrypt_private.h" @@ -363,3 +364,77 @@ bool fscrypt_mergeable_bio_bh(struct bio *bio, return fscrypt_mergeable_bio(bio, inode, next_lblk); } EXPORT_SYMBOL_GPL(fscrypt_mergeable_bio_bh); + +/** + * fscrypt_dio_supported() - check whether a direct I/O request is unsupported + * due to encryption constraints + * @iocb: the file and position the I/O is targeting + * @iter: the I/O data segment(s) + * + * Return: true if direct I/O is supported + */ +bool fscrypt_dio_supported(struct kiocb *iocb, struct iov_iter *iter) +{ + const struct inode *inode = file_inode(iocb->ki_filp); + const unsigned int blocksize = i_blocksize(inode); + + /* If the file is unencrypted, no veto from us. */ + if (!fscrypt_needs_contents_encryption(inode)) + return true; + + /* We only support direct I/O with inline crypto, not fs-layer crypto */ + if (!fscrypt_inode_uses_inline_crypto(inode)) + return false; + + /* + * Since the granularity of encryption is filesystem blocks, the I/O + * must be block aligned -- not just disk sector aligned. + */ + if (!IS_ALIGNED(iocb->ki_pos | iov_iter_count(iter), blocksize)) + return false; + + return true; +} +EXPORT_SYMBOL_GPL(fscrypt_dio_supported); + +/** + * fscrypt_limit_io_blocks() - limit I/O blocks to avoid discontiguous DUNs + * @inode: the file on which I/O is being done + * @lblk: the block at which the I/O is being started from + * @nr_blocks: the number of blocks we want to submit starting at @lblk + * + * Determine the limit to the number of blocks that can be submitted in the bio + * targeting @lblk without causing a data unit number (DUN) discontinuity. + * + * This is normally just @nr_blocks, as normally the DUNs just increment along + * with the logical blocks. (Or the file is not encrypted.) + * + * In rare cases, fscrypt can be using an IV generation method that allows the + * DUN to wrap around within logically continuous blocks, and that wraparound + * will occur. If this happens, a value less than @nr_blocks will be returned + * so that the wraparound doesn't occur in the middle of the bio. + * + * Return: the actual number of blocks that can be submitted + */ +u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, u64 nr_blocks) +{ + const struct fscrypt_info *ci = inode->i_crypt_info; + u32 dun; + + if (!fscrypt_inode_uses_inline_crypto(inode)) + return nr_blocks; + + if (nr_blocks <= 1) + return nr_blocks; + + if (!(fscrypt_policy_flags(&ci->ci_policy) & + FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) + return nr_blocks; + + /* With IV_INO_LBLK_32, the DUN can wrap around from U32_MAX to 0. */ + + dun = ci->ci_hashed_ino + lblk; + + return min_t(u64, nr_blocks, (u64)U32_MAX + 1 - dun); +} +EXPORT_SYMBOL_GPL(fscrypt_limit_io_blocks); diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 2ea1387bb497..d8dde02aee82 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -609,6 +609,10 @@ bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode, bool fscrypt_mergeable_bio_bh(struct bio *bio, const struct buffer_head *next_bh); +bool fscrypt_dio_supported(struct kiocb *iocb, struct iov_iter *iter); + +u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, u64 nr_blocks); + #else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ static inline bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode) @@ -637,6 +641,20 @@ static inline bool fscrypt_mergeable_bio_bh(struct bio *bio, { return true; } + +static inline bool fscrypt_dio_supported(struct kiocb *iocb, + struct iov_iter *iter) +{ + const struct inode *inode = file_inode(iocb->ki_filp); + + return !fscrypt_needs_contents_encryption(inode); +} + +static inline u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, + u64 nr_blocks) +{ + return nr_blocks; +} #endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ /**