Re: [PATCH 00/14] Pramfs: Persistent and protected ram filesystem

[Marco <marco.stornelli@gmail.com>]

Bryan Henderson wrote:
>> Marco wrote:
>>>    To enable direct
>>>    I/O at all times for all regular files requires either that
>>>    applications be modified to include the O_DIRECT flag on all file
>>>    opens, or that a new filesystem be used that always performs direct
>>>    I/O by default."
>> This could be done as well by just introducing a "direct_io_only"
>> mount option to a file-system which would need this feature.
> 
> But it's possible that there's just no advantage to having a block device 
> in the stack here.  When unix block devices were invented, their main 
> purpose was that they could reorder reads and writes and do buffering and 
> caching -- all things essential for disk drives.  We don't want to stretch 
> the concept too far.
> 

Yes I agree, we can't in this case talk about read and write reordering,
buffering and caching because we're talking about something completely
different from a classic disk. The issues of this kind of fs are more
similar to the tmpfs issues.

Marco