f2fs: call f2fs_wait_on_page_writeback instead of native function

If a page is on writeback, f2fs can face with deadlock due to under writepages.
This is caused by merging IOs inside f2fs, so if it comes to detect, let's throw
merged IOs, which is implemented by f2fs_wait_on_page_writeback.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 5e9c38e..9a6d8bb 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -725,7 +725,7 @@
 				f2fs_put_page(page, 1);
 				goto restart;
 			}
-			wait_on_page_writeback(page);
+			f2fs_wait_on_page_writeback(page, NODE);
 			ri->i_nid[offset[0] - NODE_DIR1_BLOCK] = 0;
 			set_page_dirty(page);
 			unlock_page(page);
@@ -814,7 +814,8 @@
 	if (unlikely(is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC)))
 		return ERR_PTR(-EPERM);
 
-	page = grab_cache_page(NODE_MAPPING(sbi), dn->nid);
+	page = grab_cache_page_write_begin(NODE_MAPPING(sbi),
+					dn->nid, AOP_FLAG_NOFS);
 	if (!page)
 		return ERR_PTR(-ENOMEM);
 
@@ -910,7 +911,8 @@
 	struct page *page;
 	int err;
 repeat:
-	page = grab_cache_page(NODE_MAPPING(sbi), nid);
+	page = grab_cache_page_write_begin(NODE_MAPPING(sbi),
+					nid, AOP_FLAG_NOFS);
 	if (!page)
 		return ERR_PTR(-ENOMEM);
 
@@ -1130,7 +1132,7 @@
 				continue;
 
 			if (ino && ino_of_node(page) == ino) {
-				wait_on_page_writeback(page);
+				f2fs_wait_on_page_writeback(page, NODE);
 				if (TestClearPageError(page))
 					ret = -EIO;
 			}
@@ -1163,7 +1165,7 @@
 	if (unlikely(sbi->por_doing))
 		goto redirty_out;
 
-	wait_on_page_writeback(page);
+	f2fs_wait_on_page_writeback(page, NODE);
 
 	/* get old block addr of this node page */
 	nid = nid_of_node(page);