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

[Changman Lee <cm224.lee@samsung.com>]

On Tue, Jul 29, 2014 at 06:24:48AM -0700, Jaegeuk Kim wrote:
> 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,
> 

We already choosed old curseg(Y) and then we allocate new address(Z) from old
curseg(Y). After that we call refresh_sit_entry(old address, new address).
In the funcation, we call locate_dirty_segment with old seg and old curseg.
So calling locate_dirty_segment after refresh_sit_entry again is redundant.

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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