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SubjectRe: [f2fs-dev] [PATCH 3/3 V2] f2fs: introduce f2fs_cache_node_page() to add page into node_inode cache
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2013-12-06 (금), 17:10 +0800, Chao Yu:
> This patch introduces f2fs_cache_node_page(), in this function, page which is
> readed ahead will be copy to node_inode's mapping cache.
> It will avoid rereading these node pages.
>
> change log:
> o check validity of grabbed page suggested by Jaegeuk Kim.
>
> Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
> Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> ---
> fs/f2fs/node.c | 35 +++++++++++++++++++++++++++++++++++
> 1 file changed, 35 insertions(+)
>
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 099f06f..3ff98fa 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1600,6 +1600,39 @@ static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages,
> return 0;
> }
>
> +/*
> + * f2fs_cache_node_page() copy updated page data to node_inode cache page.
> + */
> +void f2fs_cache_node_page(struct f2fs_sb_info *sbi, struct page *page,
> + nid_t nid)
> +{
> + struct address_space *mapping = sbi->node_inode->i_mapping;
> + struct page *npage;


What I meant for the validity was to check the block address to figure
out this node page is up-to-date or not.
IOW, something like this.

get_node_info(sbi, nid, &ni);

if (ni.blk_addr != current block address))
goto out;

npage = grab_cache_page(mapping, nid);
if (unlikely(!npage))
return;

if (unlikely(PageUptodate(npage))) {
f2fs_put_page(npage, 1);
return;
}
memcpy(page_address(npage), page_address(page), PAGE_CACHE_SIZE);

SetPageUptodate(npage);
f2fs_put_page(npage, 1);
out:
return;

> +
> + npage = find_get_page(mapping, nid);
> + if (unlikely(npage && PageUptodate(npage))) {
> + f2fs_put_page(npage, 0);
> + return;
> + }
> + f2fs_put_page(npage, 0);
> +
> + npage = grab_cache_page(mapping, nid);
> + if (unlikely(!npage))
> + return;
> +
> + if (unlikely(PageUptodate(npage))) {
> + f2fs_put_page(npage, 1);
> + return;
> + }
> +
> + memcpy(page_address(npage), page_address(page), PAGE_CACHE_SIZE);
> +
> + SetPageUptodate(npage);
> + f2fs_put_page(npage, 1);
> +
> + return;
> +}
> +
> int restore_node_summary(struct f2fs_sb_info *sbi,
> unsigned int segno, struct f2fs_summary_block *sum)
> {
> @@ -1633,6 +1666,8 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
> sum_entry->version = 0;
> sum_entry->ofs_in_node = 0;
> sum_entry++;
> + f2fs_cache_node_page(sbi, page,
> + le32_to_cpu(rn->footer.nid));
> } else {
> err = -EIO;
> }

--
Jaegeuk Kim
Samsung

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