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

Thanks, Andi. In which case sync() for direct buffered block
device access would seem to be broken in 2.4.0-prerelease.

stewart


On Tue, 2 Jan 2001, Andi Kleen wrote:

> 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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