tree f3f80253d2fbabdba0fbe35d48482d6a550ea030
parent 16865b7c42fbce8a4d2b278460e387e719e289cb
author Srinivas Eeda <srinivas.eeda@oracle.com> 1327989082 -0800
committer Joel Becker <jlbec@evilplan.org> 1341383235 -0700

ocfs2: use spinlock irqsave for downconvert lock.patch

When ocfs2dc thread holds dc_task_lock spinlock and receives soft IRQ it
deadlock itself trying to get same spinlock in ocfs2_wake_downconvert_thread.
Below is the stack snippet.

The patch disables interrupts when acquiring dc_task_lock spinlock.

	ocfs2_wake_downconvert_thread
	ocfs2_rw_unlock
	ocfs2_dio_end_io
	dio_complete
	.....
	bio_endio
	req_bio_endio
	....
	scsi_io_completion
	blk_done_softirq
	__do_softirq
	do_softirq
	irq_exit
	do_IRQ
	ocfs2_downconvert_thread
	[kthread]

Signed-off-by: Srinivas Eeda <srinivas.eeda@oracle.com>
Signed-off-by: Joel Becker <jlbec@evilplan.org>