From: Srinivas Eeda <srinivas.eeda@oracle.com>
Date: Tue, 31 Jan 2012 05:51:22 +0000 (-0800)
Subject: ocfs2: use spinlock irqsave for downconvert lock.patch
X-Git-Tag: v3.5-rc6~8^2~3
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a75e9ccabd925d16954739bd977c54695c9310d0;p=pandora-kernel.git

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>
---

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