From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chao Yu Subject: [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 Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net To: Jaegeuk Kim Return-path: Content-language: zh-cn List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net List-Id: linux-fsdevel.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 ------------------------------------------------------------------------------ The best possible search technologies are now affordable for all companies. Download your FREE open source Enterprise Search Engine today! Our experts will assist you in its installation for $59/mo, no commitment. Test it for FREE on our Cloud platform anytime! http://pubads.g.doubleclick.net/gampad/clk?id=145328191&iu=/4140/ostg.clktrk