From patchwork Mon Mar 5 16:48:18 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Colin Ian King X-Patchwork-Id: 144713 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from chlorine.canonical.com (chlorine.canonical.com [91.189.94.204]) by ozlabs.org (Postfix) with ESMTP id C3EAFB6FAA for ; Tue, 6 Mar 2012 03:48:31 +1100 (EST) Received: from localhost ([127.0.0.1] helo=chlorine.canonical.com) by chlorine.canonical.com with esmtp (Exim 4.71) (envelope-from ) id 1S4b5D-0000tT-EY; Mon, 05 Mar 2012 16:48:23 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by chlorine.canonical.com with esmtp (Exim 4.71) (envelope-from ) id 1S4b5A-0000sq-Lb for kernel-team@lists.ubuntu.com; Mon, 05 Mar 2012 16:48:20 +0000 Received: from cpc19-craw6-2-0-cust5.croy.cable.virginmedia.com ([77.102.228.6] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1S4b5A-0005Fj-Hy for kernel-team@lists.ubuntu.com; Mon, 05 Mar 2012 16:48:20 +0000 From: Colin King To: kernel-team@lists.ubuntu.com Subject: [PATCH] eCryptfs: Make truncate path killable Date: Mon, 5 Mar 2012 16:48:18 +0000 Message-Id: <1330966099-11986-2-git-send-email-colin.king@canonical.com> X-Mailer: git-send-email 1.7.9 In-Reply-To: <1330966099-11986-1-git-send-email-colin.king@canonical.com> References: <1330966099-11986-1-git-send-email-colin.king@canonical.com> X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.13 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: kernel-team-bounces@lists.ubuntu.com Errors-To: kernel-team-bounces@lists.ubuntu.com From: Tyler Hicks BugLink: http://bugs.launchpad.net/bugs/947270 ecryptfs_write() handles the truncation of eCryptfs inodes. It grabs a page, zeroes out the appropriate portions, and then encrypts the page before writing it to the lower filesystem. It was unkillable and due to the lack of sparse file support could result in tying up a large portion of system resources, while encrypting pages of zeros, with no way for the truncate operation to be stopped from userspace. This patch adds the ability for ecryptfs_write() to detect a pending fatal signal and return as gracefully as possible. The intent is to leave the lower file in a useable state, while still allowing a user to break out of the encryption loop. If a pending fatal signal is detected, the eCryptfs inode size is updated to reflect the modified inode size and then -EINTR is returned. Signed-off-by: Tyler Hicks (cherry picked from commit 5e6f0d769017cc49207ef56996e42363ec26c1f0) Signed-off-by: Colin Ian King Cc: --- fs/ecryptfs/read_write.c | 19 ++++++++++++++----- 1 files changed, 14 insertions(+), 5 deletions(-) diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c index ec3d936..608c1c3 100644 --- a/fs/ecryptfs/read_write.c +++ b/fs/ecryptfs/read_write.c @@ -132,6 +132,11 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset, size_t num_bytes = (PAGE_CACHE_SIZE - start_offset_in_page); loff_t total_remaining_bytes = ((offset + size) - pos); + if (fatal_signal_pending(current)) { + rc = -EINTR; + break; + } + if (num_bytes > total_remaining_bytes) num_bytes = total_remaining_bytes; if (pos < offset) { @@ -193,15 +198,19 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset, } pos += num_bytes; } - if ((offset + size) > ecryptfs_file_size) { - i_size_write(ecryptfs_inode, (offset + size)); + if (pos > ecryptfs_file_size) { + i_size_write(ecryptfs_inode, pos); if (crypt_stat->flags & ECRYPTFS_ENCRYPTED) { - rc = ecryptfs_write_inode_size_to_metadata( + int rc2; + + rc2 = ecryptfs_write_inode_size_to_metadata( ecryptfs_inode); - if (rc) { + if (rc2) { printk(KERN_ERR "Problem with " "ecryptfs_write_inode_size_to_metadata; " - "rc = [%d]\n", rc); + "rc = [%d]\n", rc2); + if (!rc) + rc = rc2; goto out; } }