RE: [PATCH v2 1/3] f2fs: introduce replace_block() for reuse

[Chao Yu <chao2.yu@samsung.com>]

Hi Jaegeuk,

Sorry for the delay.

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> Sent: Friday, May 01, 2015 2:04 AM
> To: Chao Yu
> Cc: Changman Lee; linux-f2fs-devel@lists.sourceforge.net; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH v2 1/3] f2fs: introduce replace_block() for reuse
> 
> Hi Chao,
> 
> On Thu, Apr 30, 2015 at 06:11:35PM +0800, Chao Yu wrote:
> > Introduce a generic function replace_block base on recover_data_page,
> > and export it. So wit it we can operate file's meta data which is in
> > CP/SSA area when we invoke fallocate with FALLOC_FL_COLLAPSE_RANGE flag.
> >
> > Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> > ---
> >  fs/f2fs/f2fs.h     |  4 ++--
> >  fs/f2fs/recovery.c |  2 +-
> >  fs/f2fs/segment.c  | 33 ++++++++++++++++++++++++++-------
> >  3 files changed, 29 insertions(+), 10 deletions(-)
> >
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index 8be6cab..7ab06e8 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -1560,8 +1560,8 @@ void write_node_page(struct f2fs_sb_info *, struct page *,
> >  void write_data_page(struct page *, struct dnode_of_data *,
> >  			struct f2fs_io_info *);
> >  void rewrite_data_page(struct page *, struct f2fs_io_info *);
> > -void recover_data_page(struct f2fs_sb_info *, struct page *,
> > -				struct f2fs_summary *, block_t, block_t);
> > +void replace_block(struct f2fs_sb_info *, struct f2fs_summary *,
> > +					block_t, block_t, bool);
> >  void allocate_data_block(struct f2fs_sb_info *, struct page *,
> >  		block_t, block_t *, struct f2fs_summary *, int);
> >  void f2fs_wait_on_page_writeback(struct page *, enum page_type);
> > diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
> > index b80d9d4..703ab2f 100644
> > --- a/fs/f2fs/recovery.c
> > +++ b/fs/f2fs/recovery.c
> > @@ -412,7 +412,7 @@ static int do_recover_data(struct f2fs_sb_info *sbi, struct inode *inode,
> >  			set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
> >
> >  			/* write dummy data page */
> > -			recover_data_page(sbi, NULL, &sum, src, dest);
> > +			replace_block(sbi, &sum, src, dest, true);
> 
> 	It's a little bit confusing.
> 	The recover_data_page wants not to recover curseg, right?
> 
> 	So, does it need to call replace_block(.., false);

You're right, my mistake. The following code in this patch should be wrong,
let me fix it as you suggested. Thank you for the review!

Regards,

> 
> >  			dn.data_blkaddr = dest;
> >  			set_data_blkaddr(&dn);
> >  			f2fs_update_extent_cache(&dn);
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index f939660..3db92fe 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -1258,26 +1258,34 @@ void rewrite_data_page(struct page *page, struct f2fs_io_info *fio)
> >  	f2fs_submit_page_mbio(F2FS_P_SB(page), page, fio);
> >  }
> >
> > -void recover_data_page(struct f2fs_sb_info *sbi,
> > -			struct page *page, struct f2fs_summary *sum,
> > -			block_t old_blkaddr, block_t new_blkaddr)
> > +void replace_block(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
> 
> How about f2fs_replace_block()?
> 
> > +				block_t old_blkaddr, block_t new_blkaddr,
> > +				bool recover_curseg)
> >  {
> >  	struct sit_info *sit_i = SIT_I(sbi);
> >  	struct curseg_info *curseg;
> >  	unsigned int segno, old_cursegno;
> >  	struct seg_entry *se;
> >  	int type;
> > +	unsigned short old_blkoff;
> >
> >  	segno = GET_SEGNO(sbi, new_blkaddr);
> >  	se = get_seg_entry(sbi, segno);
> >  	type = se->type;
> >
> > -	if (se->valid_blocks == 0 && !IS_CURSEG(sbi, segno)) {
> > -		if (old_blkaddr == NULL_ADDR)
> > -			type = CURSEG_COLD_DATA;
> > -		else
> > +	if (recover_curseg) {
> 
> 	if (!recover_curseg) { ?
> 
> > +		/* for recovery flow */
> > +		if (se->valid_blocks == 0 && !IS_CURSEG(sbi, segno)) {
> > +			if (old_blkaddr == NULL_ADDR)
> > +				type = CURSEG_COLD_DATA;
> > +			else
> > +				type = CURSEG_WARM_DATA;
> > +		}
> > +	} else {
> > +		if (!IS_CURSEG(sbi, segno))
> >  			type = CURSEG_WARM_DATA;
> >  	}
> > +
> >  	curseg = CURSEG_I(sbi, type);
> >
> >  	mutex_lock(&curseg->curseg_mutex);
> > @@ -1289,6 +1297,10 @@ void recover_data_page(struct f2fs_sb_info *sbi,
> >  	if (segno != curseg->segno) {
> >  		curseg->next_segno = segno;
> >  		change_curseg(sbi, type, true);
> > +		recover_curseg = true;
> 
> 		   ^---- Why ?
> 
> > +	} else {
> 
> 	} else if {recover_curseg) {
> 
> > +		old_blkoff = curseg->next_blkoff;
> > +		recover_curseg = false;
> 
> 		   ^---- Ditto
> 
> >  	}
> >
> >  	curseg->next_blkoff = GET_BLKOFF_FROM_SEG0(sbi, new_blkaddr);
> > @@ -1297,6 +1309,13 @@ void recover_data_page(struct f2fs_sb_info *sbi,
> >  	refresh_sit_entry(sbi, old_blkaddr, new_blkaddr);
> >  	locate_dirty_segment(sbi, old_cursegno);
> >
> > +	if (recover_curseg) {
> > +		cureg->next_segno = old_cursegno;
> > +		change_curseg(sbi, type, true);
> > +	} else {
> > +		curseg->next_blkoff = old_blkoff;
> > +	}
> 
> 	Do we have to do like this?
> 
> 	if (recover_curseg) {
> 		cureg->next_segno = old_cursegno;
> 		change_curseg(sbi, type, true);
> 		curseg->next_blkoff = old_blkoff;
> 	}
> 
> 	Thanks,
> 
> > +
> >  	mutex_unlock(&sit_i->sentry_lock);
> >  	mutex_unlock(&curseg->curseg_mutex);
> >  }
> > --
> > 2.3.3