RE: [PATCH 1/4] f2fs: limit b_size of mapped bh in f2fs_map_bh

[Chao Yu]

Hi Jaegeuk,

> -Original Message-
> From: Jaegeuk Kim [mailto:jaeg...@kernel.org]
> Sent: Tuesday, March 24, 2015 12:42 PM
> To: Chao Yu
> Cc: Changman Lee; linux-f2fs-de...@lists.sourceforge.net; 
> linux-kernel@vger.kernel.org
> Subject: Re: [PATCH 1/4] f2fs: limit b_size of mapped bh in f2fs_map_bh
> 
> Hi Chao,
> 
> On Mon, Mar 23, 2015 at 10:28:00AM +0800, Chao Yu wrote:
> > Map bh over max size which caller defined is not needed, limit it in
> > f2fs_map_bh.
> >
> > Signed-off-by: Chao Yu 
> > ---
> >  fs/f2fs/data.c | 7 ---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index f0a18a0..a99bc7f 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -255,15 +255,16 @@ static void f2fs_map_bh(struct super_block *sb, 
> > pgoff_t pgofs,
> > struct extent_info *ei, struct buffer_head *bh_result)
> >  {
> > unsigned int blkbits = sb->s_blocksize_bits;
> > +   unsigned int maxblocks = bh_result->b_size >> blkbits;
> > size_t count;
> >
> > clear_buffer_new(bh_result);
> > map_bh(bh_result, sb, ei->blk + pgofs - ei->fofs);
> > count = ei->fofs + ei->len - pgofs;
> > -   if (count < (UINT_MAX >> blkbits))
> > -   bh_result->b_size = (count << blkbits);
> > +   if (count > maxblocks)
> > +   bh_result->b_size = maxblocks << blkbits;
> > else
> > -   bh_result->b_size = UINT_MAX;
> > +   bh_result->b_size = count << blkbits;
> 
> How about using min()?

Better, I will do it. :)

Thanks,

> 
> Thanks,
> 
> >  }
> >
> >  static bool lookup_extent_info(struct inode *inode, pgoff_t pgofs,
> > --
> > 2.3.3

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Re: [PATCH 1/4] f2fs: limit b_size of mapped bh in f2fs_map_bh

[Jaegeuk Kim]

Hi Chao,

On Mon, Mar 23, 2015 at 10:28:00AM +0800, Chao Yu wrote:
> Map bh over max size which caller defined is not needed, limit it in
> f2fs_map_bh.
> 
> Signed-off-by: Chao Yu 
> ---
>  fs/f2fs/data.c | 7 ---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index f0a18a0..a99bc7f 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -255,15 +255,16 @@ static void f2fs_map_bh(struct super_block *sb, pgoff_t 
> pgofs,
>   struct extent_info *ei, struct buffer_head *bh_result)
>  {
>   unsigned int blkbits = sb->s_blocksize_bits;
> + unsigned int maxblocks = bh_result->b_size >> blkbits;
>   size_t count;
>  
>   clear_buffer_new(bh_result);
>   map_bh(bh_result, sb, ei->blk + pgofs - ei->fofs);
>   count = ei->fofs + ei->len - pgofs;
> - if (count < (UINT_MAX >> blkbits))
> - bh_result->b_size = (count << blkbits);
> + if (count > maxblocks)
> + bh_result->b_size = maxblocks << blkbits;
>   else
> - bh_result->b_size = UINT_MAX;
> + bh_result->b_size = count << blkbits;

How about using min()?

Thanks,

>  }
>  
>  static bool lookup_extent_info(struct inode *inode, pgoff_t pgofs,
> -- 
> 2.3.3
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