[Ocfs2-devel] [PATCH] ocfs2/o2hb: check len for bio_add_page() to avoid submitting incorrect bio

[piaojun <piaojun@huawei.com>]

Hi Joseph,

On 2018/3/28 12:58, Joseph Qi wrote:
> 
> 
> On 18/3/28 11:50, piaojun wrote:
>> We need check len for bio_add_page() to make sure the bio has been set up
>> correctly, otherwise we may submit incorrect data to device.
>>
>> Signed-off-by: Jun Piao <piaojun@huawei.com>
>> Reviewed-by: Yiwen Jiang <jiangyiwen@huawei.com>
>> ---
>>  fs/ocfs2/cluster/heartbeat.c | 11 ++++++++++-
>>  1 file changed, 10 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
>> index ea8c551..43ad79f 100644
>> --- a/fs/ocfs2/cluster/heartbeat.c
>> +++ b/fs/ocfs2/cluster/heartbeat.c
>> @@ -570,7 +570,16 @@ 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) break;
>> +		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,
>> +			     vec_len, vec_start,
>> +			     (unsigned long long)bio->bi_iter.bi_sector);
>> +			bio_put(bio);
>> +			bio = ERR_PTR(-EFAULT);
> 
> IMO, EFAULT is not an appropriate error code here.
> If __bio_add_page returns 0, some are caused by bio checking failed.
> Also I've noticed that several other callers just use ENOMEM, so I think
> EINVAL or ENOMEM may be better.

__bio_add_page has been deleted in patch c66a14d07c13, and I notice that
other callers always use -EFAULT or -EIO. I'm afraid we are not basing on
the same kernel source.

thansk,
Jun
> 
> Thanks,
> Joseph
> 
>> +			return bio;
>> +		}
>>
>>  		cs += vec_len / (PAGE_SIZE/spp);
>>  		vec_start = 0;
>>
> .
>