From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751936AbaE0GYj (ORCPT ); Tue, 27 May 2014 02:24:39 -0400 Received: from mailout4.samsung.com ([203.254.224.34]:10735 "EHLO mailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751441AbaE0GYh (ORCPT ); Tue, 27 May 2014 02:24:37 -0400 X-AuditID: cbfee68e-b7fb96d000004bfc-95-53842fa2d8ee Date: Tue, 27 May 2014 15:23:07 +0900 From: Changman Lee 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 Message-id: <20140527062307.GB4886@cm224.lee> References: <00f601cf7948$1263a480$372aed80$@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii Content-disposition: inline In-reply-to: <00f601cf7948$1263a480$372aed80$@samsung.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrFIsWRmVeSWpSXmKPExsVy+t8zA91F+i3BBh8vsln8b/rIZnF9118m i0uL3C327D3JYnF51xw2B1aP3Qs+M3n0bVnF6PF5k1wAcxSXTUpqTmZZapG+XQJXRt/RRqaC fuGK1eenMzcwnuHvYuTkkBAwkWibcZsVwhaTuHBvPVsXIxeHkMAyRomjfRdZYIre9e1ngUgs YpToW/4JyvnJKHHzzTdGkCoWAVWJWwvvs4HYbAJaEu2n14J1iwgoSfyav4gVpIFZYAKjxP9F 78ESwgLxEmvOXmXuYuTg4BXQlTg9OQ4kLCRgKTHryX5mEJtXQFDix+R7YOXMQDPX7zzOBGFL Szz6O4MdxOYUsJJ48+46mC0qoCIx5eQ2sBckBHaxS7y8dJcN4jgBiW+TD7GA7JIQkJXYdIAZ 4jNJiYMrbrBMYBSbhWTdLCTrZiFZt4CReRWjaGpBckFxUnqRkV5xYm5xaV66XnJ+7iZGSDz1 7WC8ecD6EGMy0MqJzFKiyfnAeMwriTc0NjOyMDUxNTYytzQjTVhJnHfRw6QgIYH0xJLU7NTU gtSi+KLSnNTiQ4xMHJxSDYxMjM82dbrYXLSw3Krt9CYlneGZZoXlcf4/kUUvnlwyj3kovNux 6sfnb/EPDutrL3tgM/d92KyoptZouX1FYoc5Mtj2fY7wVDe+eXn/rpiWg0bXFYpcXLxe/+rw 2p+/brpEEt+T/41cx62sflx+/+o8z+cgbhsR7XO/PP3MdnSEvd9Y/fjUb3MlluKMREMt5qLi RABeA8KWvQIAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFmpnleLIzCtJLcpLzFFi42I5/e+xgO4i/ZZgg/cnmCz+N31ks7i+6y+T xaVF7hZ79p5ksbi8aw6bA6vH7gWfmTz6tqxi9Pi8SS6AOaqB0SYjNTEltUghNS85PyUzL91W yTs43jne1MzAUNfQ0sJcSSEvMTfVVsnFJ0DXLTMHaKWSQlliTilQKCCxuFhJ3w7ThNAQN10L mMYIXd+QILgeIwM0kLCOMaPvaCNTQb9wxerz05kbGM/wdzFyckgImEi869vPAmGLSVy4t56t i5GLQ0hgEaNE3/JPLBDOT0aJm2++MYJUsQioStxaeJ8NxGYT0JJoP70WrFtEQEni1/xFrCAN zAITGCX+L3oPlhAWiJdYc/YqcxcjBwevgK7E6clxIGEhAUuJWU/2M4PYvAKCEj8m3wMrZwaa uX7ncSYIW1ri0d8Z7CA2p4CVxJt318FsUQEViSknt7FNYBSYhaR9FpL2WUjaFzAyr2IUTS1I LihOSs810itOzC0uzUvXS87P3cQIjtZn0jsYVzVYHGIU4GBU4uGd4NscLMSaWFZcmXuIUYKD WUmEN5apJViINyWxsiq1KD++qDQntfgQYzIwNCYyS4km5wMTSV5JvKGxiZmRpZGZhZGJuTlp wkrivAdbrQOFBNITS1KzU1MLUotgtjBxcEo1MCqruB2aw+Zrv3lZyn8ByY/3kqsuRxadKM5c 39smMJdPZXXmq5lP6o2C7lawrpA6XtyWfD9oZtbFTplpMk6ZC1Y/YH3ndbnj6EmuSV+Lz69a I/HgzkbzPe1OLMeu3nOftzR78cL6kmu/uEMWSQXOzxOa+XQJT21XTN7CPSFrxXUnR3R6Ltpp FqHEUpyRaKjFXFScCAAuy4spGgMAAA== DLP-Filter: Pass X-MTR: 20000000000000000@CPGS X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Chao Good catch. Please, modify Documentation/filesytems/f2fs.txt 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