Re: [PATCH] Remove an unnecessary line in allocate_data_block.

[Jaegeuk Kim <jaegeuk@kernel.org>]

Hi Dongho,

At first, please write a patch under the correct rule.
(e.g., description)

About this change, it's negative.
When considering SSR, we need to take care of the following scenario.
- old segno : X
- new address : Z
- old curseg : Y
This means, a new block is supposed to be written to Z from X.
And Z is newly allocated in the same path from Y.

In that case, we should trigger locate_dirty_segment for Y, since
it was a current_segment and can be dirty owing to SSR.
But that was not included in the dirty list.

Thanks,

On Mon, Jul 28, 2014 at 08:34:25AM +0000, Dongho Sim wrote:
> Hi, Chao.
> It's my mistake.
> 
> Thanks :-)
> 
> Signed-off-by: Dongho Sim <dh.sim@samsung.com>
> ---
>  fs/f2fs/segment.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 8a6e57d..7af4a8d 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -973,14 +973,12 @@ void allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
>  {
>  	struct sit_info *sit_i = SIT_I(sbi);
>  	struct curseg_info *curseg;
> -	unsigned int old_cursegno;
>  
>  	curseg = CURSEG_I(sbi, type);
>  
>  	mutex_lock(&curseg->curseg_mutex);
>  
>  	*new_blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);
> -	old_cursegno = curseg->segno;
>  
>  	/*
>  	 * __add_sum_entry should be resided under the curseg_mutex
> @@ -1001,7 +999,6 @@ void allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
>  	 * since SSR needs latest valid block information.
>  	 */
>  	refresh_sit_entry(sbi, old_blkaddr, *new_blkaddr);
> -	locate_dirty_segment(sbi, old_cursegno);
>  
>  	mutex_unlock(&sit_i->sentry_lock);
>  
> -- 
> 1.9.1
> 
> ------- Original Message -------
> Sender : ?超<chao2.yu@samsung.com> 工程?/SRC-Nanjing-Mobile Solution Lab/삼성전자
> Date : 2014-07-28 16:21 (GMT+09:00)
> Title : Re: [f2fs-dev] [PATCH] Remove an unnecessary line in allocate_data_block.
> 
> Hi Dongho,
> 
> > ----- Original Message -----
> > 
> > From： "Dongho Sim" 
> > Sent： Monday, July 28, 2014 1:51 PM
> > To： "Chao Yu" 
> > Cc： jaegeuk@kernel.org, linux-f2fs-devel@lists.sourceforge.net
> > Subject： Re: [f2fs-dev] [PATCH] Remove an unnecessary line in allocate_data_block.
> > 
> > Yes, there was another one.
> > Thanks Chao, :-)
> > 
> > Signed-off-by: Dongho Sim 
> > ---
> >  fs/f2fs/segment.c | 2 --
> >  1 file changed, 2 deletions(-)
> > 
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 8a6e57d..3ab7749 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -980,7 +980,6 @@ void allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
> >         mutex_lock(&curseg->curseg_mutex);
> > 
> >         *new_blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);
> > -       old_cursegno = curseg->segno;
> 
> The definition of old_cursegno also should be removed.
> 
> Thanks,
> Yu
> 
> > 
> >         /*
> >          * __add_sum_entry should be resided under the curseg_mutex
> > @@ -1001,7 +1000,6 @@ void allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
> >          * since SSR needs latest valid block information.
> >          */
> >         refresh_sit_entry(sbi, old_blkaddr, *new_blkaddr);
> > -       locate_dirty_segment(sbi, old_cursegno);
> > 
> >         mutex_unlock(&sit_i->sentry_lock);
> > 
> > --
> > 1.9.1
> > 
> > ------- Original Message -------
> > Sender : Chao Yu 
> > Date : 2014-07-28 14:35 (GMT+09:00)
> > Title : RE: [f2fs-dev] [PATCH] Remove an unnecessary line in allocate_data_block.
> > 
> > Hi Dongho,
> > 
> > > -----Original Message-----
> > > From: Dongho Sim [mailto:dh.sim@samsung.com]
> > > Sent: Monday, July 28, 2014 7:03 AM
> > > To: jaegeuk@kernel.org; linux-f2fs-devel@lists.sourceforge.net
> > > Subject: [f2fs-dev] [PATCH] Remove an unnecessary line in allocate_data_block.
> > >
> > > Hi. There was an unnecessary line in function, allocate_data_block.
> > > It is already done in
> > >    refresh_sit_entry(sbi, old_blkaddr, *new_blkaddr);
> > >
> > > Thanks.
> > 
> > Agreed,
> > How about removing old_cursegno too as it's no longer used in allocate_data_block?
> > 
> > Thanks,
> > Yu
> > 
> > >
> > > Signed-off-by: Dongho Sim
> > > ---
> > >  fs/f2fs/segment.c | 1 -
> > >  1 file changed, 1 deletion(-)
> > >
> > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > index 8a6e57d..a3c7aae 100644
> > > --- a/fs/f2fs/segment.c
> > > +++ b/fs/f2fs/segment.c
> > > @@ -1001,7 +1001,6 @@ void allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
> > >   * since SSR needs latest valid block information.
> > >   */
> > >   refresh_sit_entry(sbi, old_blkaddr, *new_blkaddr);
> > > - locate_dirty_segment(sbi, old_cursegno);
> > >
> > >   mutex_unlock(&sit_i->sentry_lock);
> > >
> > > --
> > > 1.9.1
> > > ------------------------------------------------------------------------------
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