f2fs: introduce f2fs_set_page_dirty_nobuffer

This patch adds f2fs_set_page_dirty_nobuffer() copied from __set_page_dirty_buffer.
When appending 4KB blocks in f2fs on pmem with multiple cores, this improves the
overall performance.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

 Conflicts:
	fs/f2fs/f2fs.h
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 0553b51..c167c31 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -367,7 +367,7 @@
 
 	SetPageUptodate(page);
 	if (!PageDirty(page)) {
-		__set_page_dirty_nobuffers(page);
+		f2fs_set_page_dirty_nobuffers(page);
 		inc_page_count(F2FS_P_SB(page), F2FS_DIRTY_META);
 		SetPagePrivate(page);
 		f2fs_trace_pid(page);
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 4927c23..8f882d6 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -20,6 +20,8 @@
 #include <linux/bio.h>
 #include <linux/prefetch.h>
 #include <linux/uio.h>
+#include <linux/mm.h>
+#include <linux/memcontrol.h>
 #include <linux/cleancache.h>
 
 #include "f2fs.h"
@@ -1801,6 +1803,33 @@
 	return 1;
 }
 
+/*
+ * This was copied from __set_page_dirty_buffers which gives higher performance
+ * in very high speed storages. (e.g., pmem)
+ */
+void f2fs_set_page_dirty_nobuffers(struct page *page)
+{
+	struct address_space *mapping = page->mapping;
+	unsigned long flags;
+
+	if (unlikely(!mapping))
+		return;
+
+	spin_lock(&mapping->private_lock);
+	SetPageDirty(page);
+	spin_unlock(&mapping->private_lock);
+
+	spin_lock_irqsave(&mapping->tree_lock, flags);
+	WARN_ON_ONCE(!PageUptodate(page));
+	account_page_dirtied(page, mapping);
+	radix_tree_tag_set(&mapping->page_tree,
+			page_index(page), PAGECACHE_TAG_DIRTY);
+	spin_unlock_irqrestore(&mapping->tree_lock, flags);
+
+	__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+	return;
+}
+
 static int f2fs_set_data_page_dirty(struct page *page)
 {
 	struct address_space *mapping = page->mapping;
@@ -1823,7 +1852,7 @@
 	}
 
 	if (!PageDirty(page)) {
-		__set_page_dirty_nobuffers(page);
+		f2fs_set_page_dirty_nobuffers(page);
 		update_dirty_page(inode, page);
 		return 1;
 	}
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index f4aa761..0b78ddd 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2120,6 +2120,7 @@
 int do_write_data_page(struct f2fs_io_info *);
 int f2fs_map_blocks(struct inode *, struct f2fs_map_blocks *, int, int);
 int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *, u64, u64);
+void f2fs_set_page_dirty_nobuffers(struct page *);
 void f2fs_invalidate_page(struct page *, unsigned long);
 int f2fs_release_page(struct page *, gfp_t);
 
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index a9195cb..64a5f99 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1663,7 +1663,7 @@
 
 	SetPageUptodate(page);
 	if (!PageDirty(page)) {
-		__set_page_dirty_nobuffers(page);
+		f2fs_set_page_dirty_nobuffers(page);
 		inc_page_count(F2FS_P_SB(page), F2FS_DIRTY_NODES);
 		SetPagePrivate(page);
 		f2fs_trace_pid(page);