GFS2: Flush pending glock work when evicting an inode

This ensures that we will not try to access the inode thats
being flushed via the glock after it has been freed.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/super.c

@@ -1557,6 +1557,7 @@ out:
 	end_writeback(inode);
 	gfs2_dir_hash_inval(ip);
 	ip->i_gl->gl_object = NULL;
+	flush_delayed_work_sync(&ip->i_gl->gl_work);
 	gfs2_glock_add_to_lru(ip->i_gl);
 	gfs2_glock_put(ip->i_gl);
 	ip->i_gl = NULL;