Re: Linux 2.6.29

[Jens Axboe]

On Tue, Mar 24 2009, Jeff Garzik wrote:
> Linus Torvalds wrote:
>> But I really don't understand filesystem people who think that "fsck" 
>> is the important part, regardless of whether the data is valid or not. 
>> That's just stupid and _obviously_ bogus.
>
> I think I can understand that point of view, at least:
>
> More customers complain about hours-long fsck times than they do about  
> silent data corruption of non-fsync'd files.
>
>
>> The point is, if you write your metadata earlier (say, every 5 sec) and 
>> the real data later (say, every 30 sec), you're actually MORE LIKELY to 
>> see corrupt files than if you try to write them together.
>>
>> And if you write your data _first_, you're never going to see 
>> corruption at all.
>
> Amen.
>
> And, personal filesystem pet peeve:  please encourage proper FLUSH CACHE  
> use to give users the data guarantees they deserve.  Linux's sync(2) and  
> fsync(2) (and fdatasync, etc.) should poke the block layer to guarantee  
> a media write.

fsync already does that, at least if you have barriers enabled on your
drive.

-- 
Jens Axboe

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/