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

[Changwei Ge]

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()
>> 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,
>>
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