From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752696AbaE0BIC (ORCPT ); Mon, 26 May 2014 21:08:02 -0400 Received: from mailout1.samsung.com ([203.254.224.24]:56010 "EHLO mailout1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752638AbaE0BHs (ORCPT ); Mon, 26 May 2014 21:07:48 -0400 X-AuditID: cbfee61b-b7fbb6d000001be3-ed-5383e562b9cf From: Chao Yu To: Jaegeuk Kim Cc: linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [f2fs-dev][PATCH] f2fs: avoid overflow when large directory feathure is enabled Date: Tue, 27 May 2014 09:06:52 +0800 Message-id: <00f601cf7948$1263a480$372aed80$@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii Content-transfer-encoding: 7bit X-Mailer: Microsoft Outlook 14.0 Thread-index: Ac95RH35p6IB48fqTU+sdKZgScEU4w== Content-language: zh-cn X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrHLMWRmVeSWpSXmKPExsVy+t9jAd2kp83BBo/u2lhc3/WXyeLSIneL PXtPslhc3jWHzYHFY/eCz0wefVtWMXp83iQXwBzFZZOSmpNZllqkb5fAlXFtRRt7wRaeiq6Z HewNjA1cXYycHBICJhLzO/4zQ9hiEhfurWfrYuTiEBJYxCjR0tvFAuH8YJS4PXsuC0gVm4CK xPKO/0wgtoiApsTj5ZvBupkFMiXuNc0As4UFoiTut85mA7FZBFQlLpy7C2bzClhKfP2ygwXC FpT4MfkeC0SvlsT6nceZIGx5ic1r3kJdpCCx4+xrRohdehKHn2xkhKgRl9h45BbLBEaBWUhG zUIyahaSUbOQtCxgZFnFKJpakFxQnJSea6RXnJhbXJqXrpecn7uJERzKz6R3MK5qsDjEKMDB qMTDO8G3OViINbGsuDL3EKMEB7OSCO+Gk0Ah3pTEyqrUovz4otKc1OJDjNIcLErivAdbrQOF BNITS1KzU1MLUotgskwcnFINjMbr7D2MpjBdOH5OfHmDZYXosSs2rke+vLIQT49jKD3WtG3d ojIG+8WCzLzWVVnn2huX/vV5171ye63BvznLT+bp3ruzy+9m1Dr7R2+qDK6dlJAwUDyyM2y2 /d/HTffEH77IfmS58JjAfzuW2dzRN7ZO+ed0gmVKm8DJSxclpljN7Ag/IpAvbKrEUpyRaKjF XFScCAAGWNleYQIAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When large directory feathure is enable, We have one case which could cause overflow in dir_buckets() as following: special case: level + dir_level >= 32 and level < MAX_DIR_HASH_DEPTH / 2. Here we define MAX_DIR_BUCKETS to limit the return value when the condition could trigger potential overflow. Signed-off-by: Chao Yu --- fs/f2fs/dir.c | 4 ++-- include/linux/f2fs_fs.h | 3 +++ 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index c3f1485..966acb0 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -23,10 +23,10 @@ static unsigned long dir_blocks(struct inode *inode) static unsigned int dir_buckets(unsigned int level, int dir_level) { - if (level < MAX_DIR_HASH_DEPTH / 2) + if (level + dir_level < MAX_DIR_HASH_DEPTH / 2) return 1 << (level + dir_level); else - return 1 << ((MAX_DIR_HASH_DEPTH / 2 + dir_level) - 1); + return MAX_DIR_BUCKETS; } static unsigned int bucket_blocks(unsigned int level) diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h index 8c03f71..ba6f312 100644 --- a/include/linux/f2fs_fs.h +++ b/include/linux/f2fs_fs.h @@ -394,6 +394,9 @@ typedef __le32 f2fs_hash_t; /* MAX level for dir lookup */ #define MAX_DIR_HASH_DEPTH 63 +/* MAX buckets in one level of dir */ +#define MAX_DIR_BUCKETS (1 << ((MAX_DIR_HASH_DEPTH / 2) - 1)) + #define SIZE_OF_DIR_ENTRY 11 /* by byte */ #define SIZE_OF_DENTRY_BITMAP ((NR_DENTRY_IN_BLOCK + BITS_PER_BYTE - 1) / \ BITS_PER_BYTE) -- 1.7.10.4