From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:37360 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753989AbeBLJmp (ORCPT ); Mon, 12 Feb 2018 04:42:45 -0500 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w1C9eghi018025 for ; Mon, 12 Feb 2018 04:42:45 -0500 Received: from e36.co.us.ibm.com (e36.co.us.ibm.com [32.97.110.154]) by mx0a-001b2d01.pphosted.com with ESMTP id 2g377ak5kv-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 12 Feb 2018 04:42:44 -0500 Received: from localhost by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 12 Feb 2018 02:42:44 -0700 From: Chandan Rajendra To: linux-ext4@vger.kernel.org Cc: Chandan Rajendra , linux-fsdevel@vger.kernel.org, ebiggers3@gmail.com, linux-fscrypt@vger.kernel.org, tytso@mit.edu Subject: [RFC PATCH V2 05/11] ext4: Decrypt all boundary blocks when doing buffered write Date: Mon, 12 Feb 2018 15:13:41 +0530 In-Reply-To: <20180212094347.22071-1-chandan@linux.vnet.ibm.com> References: <20180212094347.22071-1-chandan@linux.vnet.ibm.com> Message-Id: <20180212094347.22071-6-chandan@linux.vnet.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: With block size < page size, ext4_block_write_begin() can have up to two blocks to decrypt. Hence this commit invokes fscrypt_decrypt_block() for each of those blocks. Signed-off-by: Chandan Rajendra --- fs/ext4/inode.c | 33 +++++++++++++++++++++++---------- 1 file changed, 23 insertions(+), 10 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 69a4fd6..180dd2d 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1158,12 +1158,13 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len, unsigned to = from + len; struct inode *inode = page->mapping->host; unsigned block_start, block_end; - sector_t block; + sector_t block, page_blk_nr; 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; + int i; BUG_ON(!PageLocked(page)); BUG_ON(from > PAGE_SIZE); @@ -1224,18 +1225,30 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len, /* * 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; &wait[i] < wait_bh; i++) { + wait_on_buffer(wait[i]); + if (!buffer_uptodate(wait[i])) err = -EIO; } - if (unlikely(err)) + if (unlikely(err)) { page_zero_new_buffers(page, from, to); - else if (decrypt) { - err = fscrypt_decrypt_block(page->mapping->host, page, - PAGE_SIZE, 0, page->index); - if (err) - clear_buffer_uptodate(*wait_bh); + } else if (decrypt) { + page_blk_nr = (sector_t)page->index << (PAGE_SHIFT - bbits); + + for (i = 0; &wait[i] < wait_bh; i++) { + int err2; + + --wait_bh; + block = page_blk_nr + (bh_offset(wait[i]) >> bbits); + err2 = fscrypt_decrypt_block(page->mapping->host, page, + wait[i]->b_size, + bh_offset(wait[i]), + block); + if (err2) { + clear_buffer_uptodate(wait[i]); + err = err2; + } + } } return err; -- 2.9.5