fat_cont_expand() is the only user of sync_page_range_nolock(). It's also the
only user of generic_osync_inode() which does not have a file open.  So
opencode needed actions for FAT so that we can convert generic_osync_inode() to
a standard syncing path.
Update a comment about generic_osync_inode().
CC: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Jan Kara <jack@suse.cz>
 
        inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
        mark_inode_dirty(inode);
-       if (IS_SYNC(inode))
-               err = sync_page_range_nolock(inode, mapping, start, count);
+       if (IS_SYNC(inode)) {
+               int err2;
+
+               /*
+                * Opencode syncing since we don't have a file open to use
+                * standard fsync path.
+                */
+               err = filemap_fdatawrite_range(mapping, start,
+                                              start + count - 1);
+               err2 = sync_mapping_buffers(mapping);
+               if (!err)
+                       err = err2;
+               err2 = write_inode_now(inode, 1);
+               if (!err)
+                       err = err2;
+               if (!err) {
+                       err =  filemap_fdatawait_range(mapping, start,
+                                                      start + count - 1);
+               }
+       }
 out:
        return err;
 }
 
                MSDOS_I(inode)->i_start = new_dclus;
                MSDOS_I(inode)->i_logstart = new_dclus;
                /*
-                * Since generic_osync_inode() synchronize later if
-                * this is not directory, we don't here.
+                * Since generic_write_sync() synchronizes regular files later,
+                * we sync here only directories.
                 */
                if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) {
                        ret = fat_sync_inode(inode);