Re: sync() broken for raw devices in 2.4.x??

[Andi Kleen <ak@suse.de>]

On Mon, Jan 01, 2001 at 07:50:31PM -0500, stewart@neuron.com wrote:
> 
>  I have a sync()/fdatasync() intensive application that is designed to work
>  on both raw files and raw partitions. Today I upgraded my kernel to the
>  new pre-release and found that my benchmark program would no longer finish
>  when handed a raw partition. I've written a small Java program (my app is
>  in Java) which demonstrates the bug. Make foo.dat a raw scsi partition to
>  re-produce. In my case it's "mknod foo.dat b 8 18". 

Just a minor correction: this is not a raw partition, but a buffered blockdevice.
If you want a real rawdevice (where sync is a noop because all IO goes
synchronously to disk) you need to bind a character raw device to the
block device first using the raw util.

>From a quick look sync_buffers() [which implements fsync on block devices]
has not changed significantly between 2.2 and 2.4 and uses the same algorithm.

-Andi

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