push BKL down into ->put_super

Move BKL into ->put_super from the only caller.  A couple of
filesystems had trivial enough ->put_super (only kfree and NULLing of
s_fs_info + stuff in there) to not get any locking: coda, cramfs, efs,
hugetlbfs, omfs, qnx4, shmem, all others got the full treatment.  Most
of them probably don't need it, but I'd rather sort that out individually.
Preferably after all the other BKL pushdowns in that area.

[AV: original used to move lock_super() down as well; these changes are
removed since we don't do lock_super() at all in generic_shutdown_super()
now]
[AV: fuse, btrfs and xfs are known to need no damn BKL, exempt]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/reiserfs/super.c

@@ -465,6 +465,8 @@ static void reiserfs_put_super(struct super_block *s)
 	struct reiserfs_transaction_handle th;
 	th.t_trans_id = 0;
 
+	lock_kernel();
+
 	if (s->s_dirt)
 		reiserfs_write_super(s);
 
@@ -500,7 +502,7 @@ static void reiserfs_put_super(struct super_block *s)
 	kfree(s->s_fs_info);
 	s->s_fs_info = NULL;
 
-	return;
+	unlock_kernel();
 }
 
 static struct kmem_cache *reiserfs_inode_cachep;