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* [PATCH] Fix balance Oops
@ 2009-08-07  6:14 Yan Zheng
  2009-08-07  6:50 ` Jens Axboe
  0 siblings, 1 reply; 6+ messages in thread
From: Yan Zheng @ 2009-08-07  6:14 UTC (permalink / raw)
  To: linux-btrfs, Chris Mason

invalidate_inode_pages2_range may return -EBUSY occasionally
which results Oops. This patch fixes the issue by moving
invalidate_inode_pages2_range into a loop and keeping calling
it until the return value is not -EBUSY.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>

---
diff -urp 1/fs/btrfs/relocation.c 2/fs/btrfs/relocation.c
--- 1/fs/btrfs/relocation.c	2009-07-29 10:03:04.367858774 +0800
+++ 2/fs/btrfs/relocation.c	2009-08-07 13:26:43.882147138 +0800
@@ -2553,8 +2553,13 @@ int relocate_inode_pages(struct inode *i
 	last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
 
 	/* make sure the dirty trick played by the caller work */
-	ret = invalidate_inode_pages2_range(inode->i_mapping,
-					    first_index, last_index);
+	while (1) {
+		ret = invalidate_inode_pages2_range(inode->i_mapping,
+						    first_index, last_index);
+		if (ret != -EBUSY)
+			break;
+		cond_resched();
+	}
 	if (ret)
 		goto out_unlock;
 

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] Fix balance Oops
  2009-08-07  6:14 [PATCH] Fix balance Oops Yan Zheng
@ 2009-08-07  6:50 ` Jens Axboe
  2009-08-07  7:16   ` Yan Zheng
  0 siblings, 1 reply; 6+ messages in thread
From: Jens Axboe @ 2009-08-07  6:50 UTC (permalink / raw)
  To: Yan Zheng; +Cc: linux-btrfs, Chris Mason

On Fri, Aug 07 2009, Yan Zheng wrote:
> invalidate_inode_pages2_range may return -EBUSY occasionally
> which results Oops. This patch fixes the issue by moving
> invalidate_inode_pages2_range into a loop and keeping calling
> it until the return value is not -EBUSY.
> 
> Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
> 
> ---
> diff -urp 1/fs/btrfs/relocation.c 2/fs/btrfs/relocation.c
> --- 1/fs/btrfs/relocation.c	2009-07-29 10:03:04.367858774 +0800
> +++ 2/fs/btrfs/relocation.c	2009-08-07 13:26:43.882147138 +0800
> @@ -2553,8 +2553,13 @@ int relocate_inode_pages(struct inode *i
>  	last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
>  
>  	/* make sure the dirty trick played by the caller work */
> -	ret = invalidate_inode_pages2_range(inode->i_mapping,
> -					    first_index, last_index);
> +	while (1) {
> +		ret = invalidate_inode_pages2_range(inode->i_mapping,
> +						    first_index, last_index);
> +		if (ret != -EBUSY)
> +			break;
> +		cond_resched();
> +	}

If it returns EBUSY, would it not make more sense to call
filemap_write_and_wait_range() instead of hammering on invalidate?

-- 
Jens Axboe


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] Fix balance Oops
  2009-08-07  6:50 ` Jens Axboe
@ 2009-08-07  7:16   ` Yan Zheng
  2009-08-07  7:19     ` Jens Axboe
  0 siblings, 1 reply; 6+ messages in thread
From: Yan Zheng @ 2009-08-07  7:16 UTC (permalink / raw)
  To: Jens Axboe; +Cc: linux-btrfs, Chris Mason

On 08/07/2009 02:50 PM, Jens Axboe wrote:
> On Fri, Aug 07 2009, Yan Zheng wrote:
>> invalidate_inode_pages2_range may return -EBUSY occasionally
>> which results Oops. This patch fixes the issue by moving
>> invalidate_inode_pages2_range into a loop and keeping calling
>> it until the return value is not -EBUSY.
>>
>> Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
>>
>> ---
>> diff -urp 1/fs/btrfs/relocation.c 2/fs/btrfs/relocation.c
>> --- 1/fs/btrfs/relocation.c	2009-07-29 10:03:04.367858774 +0800
>> +++ 2/fs/btrfs/relocation.c	2009-08-07 13:26:43.882147138 +0800
>> @@ -2553,8 +2553,13 @@ int relocate_inode_pages(struct inode *i
>>  	last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
>>  
>>  	/* make sure the dirty trick played by the caller work */
>> -	ret = invalidate_inode_pages2_range(inode->i_mapping,
>> -					    first_index, last_index);
>> +	while (1) {
>> +		ret = invalidate_inode_pages2_range(inode->i_mapping,
>> +						    first_index, last_index);
>> +		if (ret != -EBUSY)
>> +			break;
>> +		cond_resched();
>> +	}
> 
> If it returns EBUSY, would it not make more sense to call
> filemap_write_and_wait_range() instead of hammering on invalidate?
> 

The pages to invalidate are not dirty, they are from page read-ahead.
Actually I have no idea how invalidate_inode_pages2_range can return
-EBUSY here. (the only user of the inode is the balancer, and it does
not hold references to the pages)

Regards
Yan, Zheng

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] Fix balance Oops
  2009-08-07  7:16   ` Yan Zheng
@ 2009-08-07  7:19     ` Jens Axboe
  2009-08-07  9:07       ` Yan Zheng
  0 siblings, 1 reply; 6+ messages in thread
From: Jens Axboe @ 2009-08-07  7:19 UTC (permalink / raw)
  To: Yan Zheng; +Cc: linux-btrfs, Chris Mason

On Fri, Aug 07 2009, Yan Zheng wrote:
> On 08/07/2009 02:50 PM, Jens Axboe wrote:
> > On Fri, Aug 07 2009, Yan Zheng wrote:
> >> invalidate_inode_pages2_range may return -EBUSY occasionally
> >> which results Oops. This patch fixes the issue by moving
> >> invalidate_inode_pages2_range into a loop and keeping calling
> >> it until the return value is not -EBUSY.
> >>
> >> Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
> >>
> >> ---
> >> diff -urp 1/fs/btrfs/relocation.c 2/fs/btrfs/relocation.c
> >> --- 1/fs/btrfs/relocation.c	2009-07-29 10:03:04.367858774 +0800
> >> +++ 2/fs/btrfs/relocation.c	2009-08-07 13:26:43.882147138 +0800
> >> @@ -2553,8 +2553,13 @@ int relocate_inode_pages(struct inode *i
> >>  	last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
> >>  
> >>  	/* make sure the dirty trick played by the caller work */
> >> -	ret = invalidate_inode_pages2_range(inode->i_mapping,
> >> -					    first_index, last_index);
> >> +	while (1) {
> >> +		ret = invalidate_inode_pages2_range(inode->i_mapping,
> >> +						    first_index, last_index);
> >> +		if (ret != -EBUSY)
> >> +			break;
> >> +		cond_resched();
> >> +	}
> > 
> > If it returns EBUSY, would it not make more sense to call
> > filemap_write_and_wait_range() instead of hammering on invalidate?
> > 
> 
> The pages to invalidate are not dirty, they are from page read-ahead.
> Actually I have no idea how invalidate_inode_pages2_range can return
> -EBUSY here. (the only user of the inode is the balancer, and it does
> not hold references to the pages)

Weird, I looked it up, and it already does a writeback wait. But I guess
that's not your issue. Patch still looks like a hack though, it would be
far better to figure out why it returns EBUSY and fix/wait appropriately
for that to pass.

-- 
Jens Axboe


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] Fix balance Oops
  2009-08-07  7:19     ` Jens Axboe
@ 2009-08-07  9:07       ` Yan Zheng
  2009-08-07 12:51         ` Chris Mason
  0 siblings, 1 reply; 6+ messages in thread
From: Yan Zheng @ 2009-08-07  9:07 UTC (permalink / raw)
  To: Jens Axboe; +Cc: linux-btrfs, Chris Mason

On 08/07/2009 03:19 PM, Jens Axboe wrote:
> On Fri, Aug 07 2009, Yan Zheng wrote:
>> On 08/07/2009 02:50 PM, Jens Axboe wrote:
>>> On Fri, Aug 07 2009, Yan Zheng wrote:
>>>> invalidate_inode_pages2_range may return -EBUSY occasionally
>>>> which results Oops. This patch fixes the issue by moving
>>>> invalidate_inode_pages2_range into a loop and keeping calling
>>>> it until the return value is not -EBUSY.
>>>>
>>>> Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
>>>>
>>>> ---
>>>> diff -urp 1/fs/btrfs/relocation.c 2/fs/btrfs/relocation.c
>>>> --- 1/fs/btrfs/relocation.c	2009-07-29 10:03:04.367858774 +0800
>>>> +++ 2/fs/btrfs/relocation.c	2009-08-07 13:26:43.882147138 +0800
>>>> @@ -2553,8 +2553,13 @@ int relocate_inode_pages(struct inode *i
>>>>  	last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
>>>>  
>>>>  	/* make sure the dirty trick played by the caller work */
>>>> -	ret = invalidate_inode_pages2_range(inode->i_mapping,
>>>> -					    first_index, last_index);
>>>> +	while (1) {
>>>> +		ret = invalidate_inode_pages2_range(inode->i_mapping,
>>>> +						    first_index, last_index);
>>>> +		if (ret != -EBUSY)
>>>> +			break;
>>>> +		cond_resched();
>>>> +	}
>>> If it returns EBUSY, would it not make more sense to call
>>> filemap_write_and_wait_range() instead of hammering on invalidate?
>>>
>> The pages to invalidate are not dirty, they are from page read-ahead.
>> Actually I have no idea how invalidate_inode_pages2_range can return
>> -EBUSY here. (the only user of the inode is the balancer, and it does
>> not hold references to the pages)
> 
> Weird, I looked it up, and it already does a writeback wait. But I guess
> that's not your issue. Patch still looks like a hack though, it would be
> far better to figure out why it returns EBUSY and fix/wait appropriately
> for that to pass.
> 

EBUSY is from the EXTENT_LOCK test in try_release_extent_state. The test
can be true is because some codes call lock_extent while corresponding
pages are not all locked. (one example is btrfs_finish_ordered_io)

Yan, Zheng

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] Fix balance Oops
  2009-08-07  9:07       ` Yan Zheng
@ 2009-08-07 12:51         ` Chris Mason
  0 siblings, 0 replies; 6+ messages in thread
From: Chris Mason @ 2009-08-07 12:51 UTC (permalink / raw)
  To: Yan Zheng; +Cc: Jens Axboe, linux-btrfs

On Fri, Aug 07, 2009 at 05:07:32PM +0800, Yan Zheng wrote:
> On 08/07/2009 03:19 PM, Jens Axboe wrote:
> > On Fri, Aug 07 2009, Yan Zheng wrote:
> >> On 08/07/2009 02:50 PM, Jens Axboe wrote:
> >>> On Fri, Aug 07 2009, Yan Zheng wrote:
> >>>> invalidate_inode_pages2_range may return -EBUSY occasionally
> >>>> which results Oops. This patch fixes the issue by moving
> >>>> invalidate_inode_pages2_range into a loop and keeping calling
> >>>> it until the return value is not -EBUSY.
> >>>>
> >>>> Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
> >>>>
> >>>> ---
> >>>> diff -urp 1/fs/btrfs/relocation.c 2/fs/btrfs/relocation.c
> >>>> --- 1/fs/btrfs/relocation.c	2009-07-29 10:03:04.367858774 +0800
> >>>> +++ 2/fs/btrfs/relocation.c	2009-08-07 13:26:43.882147138 +0800
> >>>> @@ -2553,8 +2553,13 @@ int relocate_inode_pages(struct inode *i
> >>>>  	last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
> >>>>  
> >>>>  	/* make sure the dirty trick played by the caller work */
> >>>> -	ret = invalidate_inode_pages2_range(inode->i_mapping,
> >>>> -					    first_index, last_index);
> >>>> +	while (1) {
> >>>> +		ret = invalidate_inode_pages2_range(inode->i_mapping,
> >>>> +						    first_index, last_index);
> >>>> +		if (ret != -EBUSY)
> >>>> +			break;
> >>>> +		cond_resched();
> >>>> +	}
> >>> If it returns EBUSY, would it not make more sense to call
> >>> filemap_write_and_wait_range() instead of hammering on invalidate?
> >>>
> >> The pages to invalidate are not dirty, they are from page read-ahead.
> >> Actually I have no idea how invalidate_inode_pages2_range can return
> >> -EBUSY here. (the only user of the inode is the balancer, and it does
> >> not hold references to the pages)
> > 
> > Weird, I looked it up, and it already does a writeback wait. But I guess
> > that's not your issue. Patch still looks like a hack though, it would be
> > far better to figure out why it returns EBUSY and fix/wait appropriately
> > for that to pass.
> > 
> 
> EBUSY is from the EXTENT_LOCK test in try_release_extent_state. The test
> can be true is because some codes call lock_extent while corresponding
> pages are not all locked. (one example is btrfs_finish_ordered_io)

Ok, please use schedule_timeout(HZ/10) instead then.

-chris


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2009-08-07 12:51 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2009-08-07  6:14 [PATCH] Fix balance Oops Yan Zheng
2009-08-07  6:50 ` Jens Axboe
2009-08-07  7:16   ` Yan Zheng
2009-08-07  7:19     ` Jens Axboe
2009-08-07  9:07       ` Yan Zheng
2009-08-07 12:51         ` Chris Mason

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