From patchwork Tue Apr 15 16:41:16 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukas Czerner X-Patchwork-Id: 339322 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id D1992140099 for ; Wed, 16 Apr 2014 02:41:45 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751179AbaDOQl0 (ORCPT ); Tue, 15 Apr 2014 12:41:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:65010 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751038AbaDOQlZ (ORCPT ); Tue, 15 Apr 2014 12:41:25 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s3FGfOmw013840 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 15 Apr 2014 12:41:24 -0400 Received: from localhost.localdomain.com (dhcp-1-205.brq.redhat.com [10.34.1.205]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s3FGfJDh009665; Tue, 15 Apr 2014 12:41:23 -0400 From: Lukas Czerner To: linux-fsdevel@vger.kernel.org Cc: linux-ext4@vger.kernel.org, xfs@oss.sgi.com, Lukas Czerner Subject: [PATCH 3/3 v2] fs: move falloc collapse range check into the filesystem methods Date: Tue, 15 Apr 2014 18:41:16 +0200 Message-Id: <1397580076-19826-3-git-send-email-lczerner@redhat.com> In-Reply-To: <1397580076-19826-1-git-send-email-lczerner@redhat.com> References: <1397580076-19826-1-git-send-email-lczerner@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Currently in do_fallocate in collapse range case we're checking whether offset + len is not bigger than i_size. However there is nothing which would prevent i_size from changing so the check is pointless. It should be done in the file system itself and the file system needs to make sure that i_size is not going to change. The i_size check for the other fallocate modes are also done in the filesystems. As it is now we can easily crash kernel by having two processes doing truncate and fallocate collapse range at the same time. This can be reproduced on ext4 and it is theoretically possible on xfs even though I was not able to trigger it with this simple test. This commit removes the check from do_fallocate and adds it to the file system. Signed-off-by: Lukas Czerner Acked-by: Dave Chinner Reviewed-by: Christoph Hellwig --- v2: Update description and change subject as suggested by hch fs/ext4/extents.c | 11 +++++++++-- fs/open.c | 8 -------- fs/xfs/xfs_file.c | 10 +++++++++- 3 files changed, 18 insertions(+), 11 deletions(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 0177150..ff823b7 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -5364,8 +5364,6 @@ int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len) loff_t new_size; int ret; - BUG_ON(offset + len > i_size_read(inode)); - /* Collapse range works only on fs block size aligned offsets. */ if (offset & (EXT4_BLOCK_SIZE(sb) - 1) || len & (EXT4_BLOCK_SIZE(sb) - 1)) @@ -5387,6 +5385,15 @@ int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len) /* Take mutex lock */ mutex_lock(&inode->i_mutex); + /* + * There is no need to overlap collapse range with EOF, in which case + * it is effectively a truncate operation + */ + if (offset + len >= i_size_read(inode)) { + ret = -EINVAL; + goto out_mutex; + } + if (IS_SWAPFILE(inode)) { ret = -ETXTBSY; goto out_mutex; diff --git a/fs/open.c b/fs/open.c index fe48b2f..bd42341 100644 --- a/fs/open.c +++ b/fs/open.c @@ -284,14 +284,6 @@ int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len) if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0)) return -EFBIG; - /* - * There is no need to overlap collapse range with EOF, in which case - * it is effectively a truncate operation - */ - if ((mode & FALLOC_FL_COLLAPSE_RANGE) && - (offset + len >= i_size_read(inode))) - return -EINVAL; - if (!file->f_op->fallocate) return -EOPNOTSUPP; diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 003c005..4ba0ae9 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -840,7 +840,15 @@ xfs_file_fallocate( goto out_unlock; } - ASSERT(offset + len < i_size_read(inode)); + /* + * There is no need to overlap collapse range with EOF, + * in which case it is effectively a truncate operation + */ + if (offset + len >= i_size_read(inode)) { + error = -EINVAL; + goto out_unlock; + } + new_size = i_size_read(inode) - len; error = xfs_collapse_file_space(ip, offset, len);