Re: [PATCH v2 2/4] ocfs2: sysfile interfaces for online file check

[Junxiao Bi <junxiao.bi@oracle.com>]

Hi Gang,

On 11/25/2015 11:29 AM, Gang He wrote:
> Hi Mark and Junxiao,
> 
> 
>>>>
>> On Tue, Nov 03, 2015 at 04:20:27PM +0800, Junxiao Bi wrote:
>>> Hi Gang,
>>>
>>> On 11/03/2015 03:54 PM, Gang He wrote:
>>>> Hi Junxiao,
>>>>
>>>> Thank for your reviewing.
>>>> Current design, we use a sysfile as a interface to check/fix a file (via 
>> pass a ino number).
>>>> But, this operation is manually triggered by user, instead of automatically 
>>  fix in the kernel.
>>>> Why?
>>>> 1) we should let users make this decision, since some users do not want to 
>> fix when encountering a file system corruption, maybe they want to keep the 
>> file system unchanged for a further investigation.
>>> If user don't want this, they should not use error=continue option, let
>>> fs go after a corruption is very dangerous.
>>
>> Maybe we need another errors=XXX flag (maybe errors=fix)?
>>
>> You both make good points, here's what I gather from the conversation:
>>
>>  - Some customers would be sad if they have to manually fix corruptions.
>>    This takes effort on their part, and if the FS can handle it
>>    automatically, it should.
>>
>>  - There are valid concerns that automatically fixing things is a change in
>>    behavior that might not be welcome, or worse might lead to unforseeable
>>    circumstances.
>>
>>  - I will add that fixing things automatically implies checking them
>>    automatically which could introduce some performance impact depending on
>>    how much checking we're doing.
>>
>> So if the user wants errors to be fixed automatically, they could mount with
>> errros=fix, and everyone else would have no change in behavior unless they
>> wanted to make use of the new feature.
> That is what I want to say, add a mount option to let users to decide. Here, I want to split "error=fix"
> mount option  task out from online file check feature, I think this part should be a independent feature.
> We can implement this feature after online file check is done, I want to split the feature into some more 
> detailed features, implement them one by one. Do you agree this point?
With error=fix, when a possible corruption is found, online fsck will
start to check and fix things. So this doesn't looks like a independent
feature.

Thanks,
Junxiao.

> 
>>
>>
>>>> 2) frankly speaking, this feature will probably bring a second corruption 
>> if there is some error in the code, I do not suggest to use automatically fix 
>> by default in the first version.
>>> I think if this feature could bring more corruption, then this should be
>>> fixed first.
>>
>> Btw, I am pretty sure that Gang is referring to the feature being new and
>> thus more likely to have problems. There is nothing I see in here that is
>> file system corrupting.
>> 	--Mark
>>
>>
>> --
>> Mark Fasheh
>