f2fs: use highmem for directory pages

This patch fixes to use highmem for directory pages.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 0deead4..52d6f54 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -156,7 +156,7 @@
 		inode->i_op = &f2fs_dir_inode_operations;
 		inode->i_fop = &f2fs_dir_operations;
 		inode->i_mapping->a_ops = &f2fs_dblock_aops;
-		mapping_set_gfp_mask(inode->i_mapping, GFP_F2FS_ZERO);
+		mapping_set_gfp_mask(inode->i_mapping, GFP_F2FS_HIGH_ZERO);
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &f2fs_symlink_inode_operations;
 		inode->i_mapping->a_ops = &f2fs_dblock_aops;