Hi changman, > -----Original Message----- > From: Changman Lee [mailto:cm224.lee@xxxxxxxxxxx] > Sent: Tuesday, May 27, 2014 2:23 PM > To: Chao Yu > Cc: Jaegeuk Kim; linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > 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 <chao2.yu@xxxxxxxxxxx> > > --- > > 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@xxxxxxxxxxxxxxxxxxxxx > > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
