Re: [PATCH 4/6] f2fs: avoid multiple node page writes due to inline_data

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

Hi Jaegeuk,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> Sent: Tuesday, January 26, 2016 6:05 AM
> To: linux-kernel@vger.kernel.org; linux-fsdevel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Cc: Jaegeuk Kim
> Subject: [f2fs-dev] [PATCH 4/6] f2fs: avoid multiple node page writes due to inline_data
> 
> The sceanrio is:
> 1. create fully node blocks
> 2. flush node blocks
> 3. write inline_data for all the node blocks again
> 4. flush node blocks redundantly
> 
> So, this patch tries to flush inline_data when flushing node blocks.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/data.c   |  1 +
>  fs/f2fs/inline.c |  2 ++
>  fs/f2fs/node.c   | 39 +++++++++++++++++++++++++++++++++++++++
>  fs/f2fs/node.h   | 15 +++++++++++++++
>  4 files changed, 57 insertions(+)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 89a37ba..260c0eb 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1463,6 +1463,7 @@ restart:
>  		if (pos + len <= MAX_INLINE_DATA) {
>  			read_inline_data(page, ipage);
>  			set_inode_flag(F2FS_I(inode), FI_DATA_EXIST);
> +			set_inline_node(ipage);
>  			sync_inode_page(&dn);
>  		} else {
>  			err = f2fs_convert_inline_page(&dn, page);
> diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
> index 8df13e5..fc4d298 100644
> --- a/fs/f2fs/inline.c
> +++ b/fs/f2fs/inline.c
> @@ -159,6 +159,7 @@ no_update:
> 
>  	/* clear inline data and flag after data writeback */
>  	truncate_inline_inode(dn->inode_page, 0);
> +	clear_inline_node(dn->inode_page);
>  clear_out:
>  	stat_dec_inline_inode(dn->inode);
>  	f2fs_clear_inline_inode(dn->inode);
> @@ -233,6 +234,7 @@ int f2fs_write_inline_data(struct inode *inode, struct page *page)
>  	set_inode_flag(F2FS_I(inode), FI_DATA_EXIST);
> 
>  	sync_inode_page(&dn);
> +	clear_inline_node(dn.inode_page);
>  	f2fs_put_dnode(&dn);
>  	return 0;
>  }
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 23b800d..94a6755 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1154,6 +1154,37 @@ void sync_inode_page(struct dnode_of_data *dn)
>  	dn->node_changed = ret ? true: false;
>  }
> 
> +static void flush_inline_data(struct f2fs_sb_info *sbi, nid_t ino)
> +{
> +	struct inode *inode;
> +	struct page *page;
> +
> +	/* should flush inline_data before evict_inode */
> +	inode = ilookup(sbi->sb, ino);
> +	if (!inode)
> +		return;
> +
> +	page = pagecache_get_page(inode->i_mapping, 0, FGP_LOCK|FGP_NOWAIT, 0);
> +	if (!page)
> +		goto iput_out;
> +
> +	if (!PageUptodate(page))
> +		goto page_out;
> +
> +	if (!PageDirty(page))
> +		goto page_out;
> +
> +	if (!clear_page_dirty_for_io(page))
> +		goto page_out;
> +
> +	if (!f2fs_write_inline_data(inode, page))

better to redirty the page when fail except -EAGAIN?

> +		inode_dec_dirty_pages(inode);
> +page_out:
> +	f2fs_put_page(page, 1);
> +iput_out:
> +	iput(inode);
> +}
> +
>  int sync_node_pages(struct f2fs_sb_info *sbi, nid_t ino,
>  					struct writeback_control *wbc)
>  {
> @@ -1221,6 +1252,14 @@ continue_unlock:
>  				goto continue_unlock;
>  			}
> 
> +			/* flush inline_data */
> +			if (!ino && is_inline_node(page)) {
> +				clear_inline_node(page);

Should clear after flushed inline data? otherwise if we failed to flush
inline data, we will lose the change to flush it before node flush.

Thanks,

> +				unlock_page(page);
> +				flush_inline_data(sbi, ino_of_node(page));
> +				continue;
> +			}
> +
>  			if (!clear_page_dirty_for_io(page))
>  				goto continue_unlock;
> 
> diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h
> index 23bd992..1f4f9d4 100644
> --- a/fs/f2fs/node.h
> +++ b/fs/f2fs/node.h
> @@ -379,6 +379,21 @@ static inline int is_node(struct page *page, int type)
>  #define is_fsync_dnode(page)	is_node(page, FSYNC_BIT_SHIFT)
>  #define is_dent_dnode(page)	is_node(page, DENT_BIT_SHIFT)
> 
> +static inline int is_inline_node(struct page *page)
> +{
> +	return PageChecked(page);
> +}
> +
> +static inline void set_inline_node(struct page *page)
> +{
> +	SetPageChecked(page);
> +}
> +
> +static inline void clear_inline_node(struct page *page)
> +{
> +	ClearPageChecked(page);
> +}
> +
>  static inline void set_cold_node(struct inode *inode, struct page *page)
>  {
>  	struct f2fs_node *rn = F2FS_NODE(page);
> --
> 2.6.3
> 
> 
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