[f2fs-dev] [PATCH 3/3 V2] f2fs: introduce f2fs_cache_node_page() to add page into node_inode cache

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

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;
+
+	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;
 			}
-- 
1.7.9.5