f2fs: add prefix for exported symbols

to avoid polluting global symbol namespace.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 98721f9..e15d4ce 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -105,11 +105,11 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf)
 
 	if (need_alloc) {
 		/* block allocation */
-		__do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, true);
+		f2fs_do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, true);
 		set_new_dnode(&dn, inode, NULL, NULL, 0);
 		err = f2fs_get_block(&dn, page->index);
 		f2fs_put_dnode(&dn);
-		__do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, false);
+		f2fs_do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, false);
 	}
 
 #ifdef CONFIG_F2FS_FS_COMPRESSION