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.e...@oracle.com>
---
fs/ocfs2/dlmglue.c | 30 ++++++++++++++++++------------
1 files changed, 18 insertions(+), 12 deletions(-)
diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index 81a4cd2..d8552a5 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -3932,6 +3932,8 @@ unqueue:
static void ocfs2_schedule_blocked_lock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres)
{
+ unsigned long flags;
+
assert_spin_locked(&lockres->l_lock);
if (lockres->l_flags & OCFS2_LOCK_FREEING) {
@@ -3945,21 +3947,22 @@ static void ocfs2_schedule_blocked_lock(struct
ocfs2_super *osb,
lockres_or_flags(lockres, OCFS2_LOCK_QUEUED);
- spin_lock(&osb->dc_task_lock);
+ spin_lock_irqsave(&osb->dc_task_lock, flags);
if (list_empty(&lockres->l_blocked_list)) {
list_add_tail(&lockres->l_blocked_list,
&osb->blocked_lock_list);
osb->blocked_lock_count++;
}
- spin_unlock(&osb->dc_task_lock);
+ spin_unlock_irqrestore(&osb->dc_task_lock, flags);
}
static void ocfs2_downconvert_thread_do_work(struct ocfs2_super *osb)
{
unsigned long processed;
+ unsigned long flags;
struct ocfs2_lock_res *lockres;
- spin_lock(&osb->dc_task_lock);
+ spin_lock_irqsave(&osb->dc_task_lock, flags);
/* grab this early so we know to try again if a state change and
* wake happens part-way through our work */
osb->dc_work_sequence = osb->dc_wake_sequence;
@@ -3972,38 +3975,40 @@ static void ocfs2_downconvert_thread_do_work(struct
ocfs2_super *osb)
struct ocfs2_lock_res, l_blocked_list);
list_del_init(&lockres->l_blocked_list);
osb->blocked_lock_count--;
- spin_unlock(&osb->dc_task_lock);
+ spin_unlock_irqrestore(&osb->dc_task_lock, flags);
BUG_ON(!processed);
processed--;
ocfs2_process_blocked_lock(osb, lockres);
- spin_lock(&osb->dc_task_lock);
+ spin_lock_irqsave(&osb->dc_task_lock, flags);
}
- spin_unlock(&osb->dc_task_lock);
+ spin_unlock_irqrestore(&osb->dc_task_lock, flags);
}
static int ocfs2_downconvert_thread_lists_empty(struct ocfs2_super *osb)
{
int empty = 0;
+ unsigned long flags;
- spin_lock(&osb->dc_task_lock);
+ spin_lock_irqsave(&osb->dc_task_lock, flags);
if (list_empty(&osb->blocked_lock_list))
empty = 1;
- spin_unlock(&osb->dc_task_lock);
+ spin_unlock_irqrestore(&osb->dc_task_lock, flags);
return empty;
}
static int ocfs2_downconvert_thread_should_wake(struct ocfs2_super *osb)
{
int should_wake = 0;
+ unsigned long flags;
- spin_lock(&osb->dc_task_lock);
+ spin_lock_irqsave(&osb->dc_task_lock, flags);
if (osb->dc_work_sequence != osb->dc_wake_sequence)
should_wake = 1;
- spin_unlock(&osb->dc_task_lock);
+ spin_unlock_irqrestore(&osb->dc_task_lock, flags);
return should_wake;
}
@@ -4033,10 +4038,11 @@ static int ocfs2_downconvert_thread(void *arg)
void ocfs2_wake_downconvert_thread(struct ocfs2_super *osb)
{
- spin_lock(&osb->dc_task_lock);
+ unsigned long flags;
+ spin_lock_irqsave(&osb->dc_task_lock, flags);
/* make sure the voting thread gets a swipe at whatever changes
* the caller may have made to the voting state */
osb->dc_wake_sequence++;
- spin_unlock(&osb->dc_task_lock);
+ spin_unlock_irqrestore(&osb->dc_task_lock, flags);
wake_up(&osb->dc_event);
}
--
1.5.4.3
_______________________________________________
Ocfs2-devel mailing list
Ocfs2-devel@oss.oracle.com
http://oss.oracle.com/mailman/listinfo/ocfs2-devel
