b2b7d089f7
Eliminates panics due to locking issues. Idea taken from src/sys/gnu/fs/xfs/FreeBSD/xfs_super.c. PR: 89966, 92000, 104393 Reported by: H. Matsuo <hiroshi50000 yahoo co jp>, Chris <m2chrischou gmail.com>, Andrey V. Elsukov <bu7cher yandex ru>, Jan Henrik Sylvester <me janh de> Approved by: re (kensmith)