From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751988AbaE0Iup (ORCPT ); Tue, 27 May 2014 04:50:45 -0400 Received: from mailout3.samsung.com ([203.254.224.33]:48800 "EHLO mailout3.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751406AbaE0Iul (ORCPT ); Tue, 27 May 2014 04:50:41 -0400 X-AuditID: cbfee61b-b7fbb6d000001be3-80-538451de449e From: Chao Yu To: "'Changman Lee'" Cc: "'Jaegeuk Kim'" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net References: <00f601cf7948$1263a480$372aed80$@samsung.com> <20140527062307.GB4886@cm224.lee> In-reply-to: <20140527062307.GB4886@cm224.lee> Subject: RE: [f2fs-dev] [PATCH] f2fs: avoid overflow when large directory feathure is enabled Date: Tue, 27 May 2014 16:49:49 +0800 Message-id: <010701cf7988$bc218420$34648c60$@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: AQLARk+s/Gy8LVAXYjPcNN6ljA7IuwJGpqrtmWBNa/A= Content-language: zh-cn X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrNLMWRmVeSWpSXmKPExsVy+t9jAd37gS3BBp+Xslpc29fIZHF9118m i0uL3C327D3JYnF51xw2B1aP3Qs+M3n0bVnF6PF5k1wAcxSXTUpqTmZZapG+XQJXxoHv4QVX xCu67vxhb2CcINzFyMkhIWAi8aavhRXCFpO4cG89WxcjF4eQwCJGid7Nh9khnB+MEvN+tjOD VLEJqEgs7/jPBGKLCGhJ7O/pZgEpYhaYxCix5GczC0hCSCBWYt+pz2BjOQX0JLrermcHsYUF 4iWmvlkDZrMIqEqc//EdbBCvgKVEx26Iel4BQYkfk++BzWEGWrB+53EmCFteYvOat8wQpypI 7Dj7mhHiCCuJhz3L2CBqxCU2HrnFMoFRaBaSUbOQjJqFZNQsJC0LGFlWMYqmFiQXFCel5xrp FSfmFpfmpesl5+duYgRHwTPpHYyrGiwOMQpwMCrx8E7wbQ4WYk0sK67MPcQowcGsJMLb6dIS LMSbklhZlVqUH19UmpNafIhRmoNFSZz3YKt1oJBAemJJanZqakFqEUyWiYNTqoGx9nhCnChD +ZplK33ZLgsasN7UW8K78I7Ax/lV6eU2X2c8ClHker8+V8PPKX5S4dvMPUZ7Toes6+LnO6mc v9n7jP5xM4evlo/37wooajq6ccbSJHbdCYuL1QUnT5x49K7Ve++vhvoXWPrWvtOaraftdTRi 2Sfr+pTm37UZshZvM6/ldWp+Ov1GiaU4I9FQi7moOBEAFYqiV34CAAA= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi changman, > -----Original Message----- > From: Changman Lee [mailto:cm224.lee@samsung.com] > Sent: Tuesday, May 27, 2014 2:23 PM > To: Chao Yu > Cc: Jaegeuk Kim; linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; > linux-f2fs-devel@lists.sourceforge.net > Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid overflow when large directory feathure is enabled > > Hi, Chao > Good catch. Please, modify Documentation/filesytems/f2fs.txt Thank you for reminding me, I will add modification of f2fs.txt in the patch later. > > On Tue, May 27, 2014 at 09:06:52AM +0800, Chao Yu wrote: > > 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 > > _______________________________________________ > > Linux-f2fs-devel mailing list > > Linux-f2fs-devel@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel