[Ocfs2-devel] [PATCH] ocfs2: submit another bio if current bio is full

[Changwei Ge]

Hi Jun,


On 2018/5/9 16:50, piaojun wrote:
> Hi Changwei,
>
> On 2018/5/8 23:57, Changwei Ge wrote:
>> Hi Jun,
>>
>> Sorry for this so late reply since I was very busy those days.
>>
>>
>> On 04/16/2018 11:44 AM, piaojun wrote:
>>> Hi Changwei,
>>>
>>> Do you mean that if the slotnum exceed 16 like 'mkfs.ocfs2 -N 17', you
>>> still let it go rather than reture error?
>> If your assumption is right, do you mean that ocfs2 slots can't exceed 16?
>>
>> If you return error once slots exceed 16, mkfs will never succeed.
>>
>> So if we can ensure that bio is full in current iteration, we should run
>> into next iteration and allocate a
>> new bio adding pages and continue.
>>
>> And your patch makes my ocfs2-test fail.
>>
>>
>> Thanks,
>> Changwei
>>
>>> thanks,
>>> Jun
>>>
>>> On 2018/4/13 13:51, Changwei Ge wrote:
>>>> If cluster scale exceeds 16 nodes, bio will be full and bio_add_page()
> Sorry for misunderstanding your fix, and do you mean that the node num is
> a little big which could not be covered by 16 pages, such as 129?
>
> "one page could cover 8 node's slots"
It has nothing to do with the capacity of page holding slots.
It's about how many vecs a bio can have.

For your reference, bio_alloc() has set the maximum vec to 16 in 
o2hb_setup_one_bio() as precondition.

Thanks,
Changwei

>
> thanks,
> Jun
>
>>>> returns 0 when adding pages to bio. Returning -EIO to o2hb_read_slots()
>>>> from o2hb_setup_one_bio() will lead to losing chance to allocate more
>>>> bios to present all heartbeat region.
>>>>
>>>> So o2hb_read_slots() fails.
>>>>
>>>> In my test, making fs fails in starting o2cb service.
>>>>
>>>> Attach error log:
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 0, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 1, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 2, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 3, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 4, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 5, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 6, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 7, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 8, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 9, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 10, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 11, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 12, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 13, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 14, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 15, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:463 page 16, vec_len = 4096, vec_start = 0
>>>> (mkfs.ocfs2,27479,2):o2hb_setup_one_bio:471 ERROR: Adding page[16] to bio failed, page ffffea0002d7ed40, len 0, vec_len 4096, vec_start 0, bi_sector 8192
>>>> (mkfs.ocfs2,27479,2):o2hb_read_slots:500 ERROR: status = -5
>>>> (mkfs.ocfs2,27479,2):o2hb_populate_slot_data:1911 ERROR: status = -5
>>>> (mkfs.ocfs2,27479,2):o2hb_region_dev_write:2012 ERROR: status = -5
>>>>
>>>> Fixes: ba16ddfbeb9d ("ocfs2/o2hb: check len for bio_add_page() to avoid getting incorrect bio"
>>>>
>>>> Signed-off-by: Changwei Ge <ge.changwei at h3c.com>
>>>> ---
>>>>    fs/ocfs2/cluster/heartbeat.c | 8 ++++++--
>>>>    1 file changed, 6 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
>>>> index 91a8889abf9b..2809e29d612d 100644
>>>> --- a/fs/ocfs2/cluster/heartbeat.c
>>>> +++ b/fs/ocfs2/cluster/heartbeat.c
>>>> @@ -540,11 +540,12 @@ static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
>>>>    	struct bio *bio;
>>>>    	struct page *page;
>>>>    
>>>> +#define O2HB_BIO_VECS 16
>>>>    	/* Testing has shown this allocation to take long enough under
>>>>    	 * GFP_KERNEL that the local node can get fenced. It would be
>>>>    	 * nicest if we could pre-allocate these bios and avoid this
>>>>    	 * all together. */
>>>> -	bio = bio_alloc(GFP_ATOMIC, 16);
>>>> +	bio = bio_alloc(GFP_ATOMIC, O2HB_BIO_VECS);
>>>>    	if (!bio) {
>>>>    		mlog(ML_ERROR, "Could not alloc slots BIO!\n");
>>>>    		bio = ERR_PTR(-ENOMEM);
>>>> @@ -570,7 +571,10 @@ static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
>>>>    		     current_page, vec_len, vec_start);
>>>>    
>>>>    		len = bio_add_page(bio, page, vec_len, vec_start);
>>>> -		if (len != vec_len) {
>>>> +		if (len == 0 && current_page == O2HB_BIO_VECS) {
>>>> +			/* bio is full now. */
>>>> +			goto bail;
>>>> +		} else if (len != vec_len) {
>>>>    			mlog(ML_ERROR, "Adding page[%d] to bio failed, "
>>>>    			     "page %p, len %d, vec_len %u, vec_start %u, "
>>>>    			     "bi_sector %llu\n", current_page, page, len,
>>>>
>>> _______________________________________________
>>> Ocfs2-devel mailing list
>>> Ocfs2-devel at oss.oracle.com
>>> https://oss.oracle.com/mailman/listinfo/ocfs2-devel