From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 3FF63C072A4 for ; Mon, 20 May 2019 16:30:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 16229217F4 for ; Mon, 20 May 2019 16:30:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1558369829; bh=jzDa4sIscNqlfHv7tNu4xnhMMMwK6J7mZB9Z89E3MiY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=HOL4+Tsg/KQoSD/eWkObpeeniLPBcq0eyqQPRjzs2gLxnUvCr3TkRguNrgrxuCKSh WH4cAC/AV3ZRCj6c/HwIlkq8a3j+QLVRYZn0oplRAXexLHCU1b5/PSGSqACsyNdSsW kK99bsxiAXYmRSp3F5KxlULVcj4Z2DKtpQXfXGVs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392336AbfETQa1 (ORCPT ); Mon, 20 May 2019 12:30:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:44922 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392231AbfETQaZ (ORCPT ); Mon, 20 May 2019 12:30:25 -0400 Received: from ebiggers-linuxstation.mtv.corp.google.com (unknown [104.132.1.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C8212217D4; Mon, 20 May 2019 16:30:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1558369825; bh=jzDa4sIscNqlfHv7tNu4xnhMMMwK6J7mZB9Z89E3MiY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ob/JPjcP7714BGREu627MvS2LQxzV4JLdnXXWnMnDH1YTlzvo+9t2j3I8S0VudDhS 92QsFC9y2jHVMwi4utg/5SWjCEOHa1YtdAC7FNlADEUtX7+2Dy4fSi2Eh4HmQr2LUQ Yja0pYrVp6mCFfIxfZ6/DnkEoG3ukGh4lW90ADZk= From: Eric Biggers To: linux-fscrypt@vger.kernel.org Cc: linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mtd@lists.infradead.org, Chandan Rajendra Subject: [PATCH v2 12/14] ext4: decrypt only the needed blocks in ext4_block_write_begin() Date: Mon, 20 May 2019 09:29:50 -0700 Message-Id: <20190520162952.156212-13-ebiggers@kernel.org> X-Mailer: git-send-email 2.21.0.1020.gf2820cf01a-goog In-Reply-To: <20190520162952.156212-1-ebiggers@kernel.org> References: <20190520162952.156212-1-ebiggers@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org From: Chandan Rajendra In ext4_block_write_begin(), only decrypt the blocks that actually need to be decrypted (up to two blocks which intersect the boundaries of the region that will be written to), rather than assuming blocksize == PAGE_SIZE and decrypting the whole page. This is in preparation for allowing encryption on ext4 filesystems with blocksize != PAGE_SIZE. Signed-off-by: Chandan Rajendra (EB: rebase onto previous changes, improve the commit message, and move the check for encrypted inode) Signed-off-by: Eric Biggers --- fs/ext4/inode.c | 29 ++++++++++++++++++----------- 1 file changed, 18 insertions(+), 11 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 0e6536a22a465..8b3ea9c8ac988 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1164,8 +1164,9 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len, int err = 0; unsigned blocksize = inode->i_sb->s_blocksize; unsigned bbits; - struct buffer_head *bh, *head, *wait[2], **wait_bh = wait; - bool decrypt = false; + struct buffer_head *bh, *head, *wait[2]; + int nr_wait = 0; + int i; BUG_ON(!PageLocked(page)); BUG_ON(from > PAGE_SIZE); @@ -1217,24 +1218,30 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len, !buffer_unwritten(bh) && (block_start < from || block_end > to)) { ll_rw_block(REQ_OP_READ, 0, 1, &bh); - *wait_bh++ = bh; - decrypt = IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode); + wait[nr_wait++] = bh; } } /* * If we issued read requests, let them complete. */ - while (wait_bh > wait) { - wait_on_buffer(*--wait_bh); - if (!buffer_uptodate(*wait_bh)) + for (i = 0; i < nr_wait; i++) { + wait_on_buffer(wait[i]); + if (!buffer_uptodate(wait[i])) err = -EIO; } if (unlikely(err)) { page_zero_new_buffers(page, from, to); - } else if (decrypt) { - err = fscrypt_decrypt_pagecache_blocks(page, PAGE_SIZE, 0); - if (err) - clear_buffer_uptodate(*wait_bh); + } else if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode)) { + for (i = 0; i < nr_wait; i++) { + int err2; + + err2 = fscrypt_decrypt_pagecache_blocks(page, blocksize, + bh_offset(wait[i])); + if (err2) { + clear_buffer_uptodate(wait[i]); + err = err2; + } + } } return err; -- 2.21.0.1020.gf2820cf01a-goog