Re: [PATCH] makedumpfile: assign bitmap2 fd for sub process during refiltering

[piliu <piliu@redhat.com>]

On 12/07/2019 06:11 AM, Kazuhito Hagio wrote:
> Hi Pingfan,
> 
>> -----Original Message-----
>> In refiltering mode, each sub process inherits bitmap2->fd from parent.
>> Then they lseek()/read() on the same fd, which means that they interference
>> with each other.
>>
>> This breaks the purpose of SPLITTING_FD_BITMAP(i) for each sub process.
>> Fix it by assigning a sub process dedicated fd to bitmap2->fd.
>>
>> Signed-off-by: Pingfan Liu <piliu@redhat.com>
> 
> Thanks for the patch.
> I'm still reading the code, but it might be better to apply this to bitmap1->fd
> as well?  see you next week..
Yes. Although during my test, bitmap1 is not touched, but it is a
reasonable step to against any future bug.

Thanks,
Pingfan
> 
> Thanks,
> Kazu
> 
>> ---
>>  makedumpfile.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/makedumpfile.c b/makedumpfile.c
>> index d76a435..1dc8640 100644
>> --- a/makedumpfile.c
>> +++ b/makedumpfile.c
>> @@ -8857,7 +8857,8 @@ write_kdump_pages_and_bitmap_cyclic(struct cache_data *cd_header, struct cache_d
>>  	if (info->flag_cyclic) {
>>  		if (!prepare_bitmap2_buffer())
>>  			return FALSE;
>> -	}
>> +	} else if (info->flag_refiltering)
>> +		info->bitmap2->fd = info->fd_bitmap;
>>
>>  	/*
>>  	 * Write pages and bitmap cyclically.
>> --
>> 2.7.5
>>
> 
> 
> 
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