AutoFsck - Technical Review

[Phillip Susi]

Aigars Mahinovs wrote:
>> (2) get rid of the mount count check altogether
>>
> 
> There is a way to get (2), but that would require quite a lot of
> in-kernel work, that would also be required for
> defragmetnation-on-the-run.

No, disabling the mount count check altogether just requires using 
tune2fs ( or having mkfs do it originally ) to set the mount check count 
to 0.

> The most correct way, IMHO would be to perform both disk checks and
> defragmentation in kernel, in the background of a running system
> during the drive idle time and just have the user-space control when
> that can happen (for power saving purposes or to let user pause
> auto-defrag to get more FPS out of their game).

That greatly complicates the kernel, making kernel bugs more likely and 
chewing up more non pageable ram.  Also you run into the issue of what 
to do when you find something wrong, and the fact that you may have made 
the disk worse while writing to it when it was damaged but you did not 
detect it until some time later.

> This could reduce the regular filesystem check on bootup to a O(1)
> time check of 5-15 seconds, if the bulk of the work over the
> filesystem is done over the runtime and remove the need for a regular
> defragmentation.

There already is no need for regular defragmentation ;)