Re: Disk write cache

[Andi Kleen]

Jeff Garzik <jgarzik@xxxxxxxxx> writes:
>
> The ability of a filesystem or fsync(2) to cause a [FLUSH|SYNC] CACHE
> command to be generated has only been present in the most recent 2.6.x
> kernels.  See the "write barrier" stuff that people have been
> discussing.

Are you sure mainline does it for fsync() file data at all? iirc it
was only done for journal writes in reiserfs/xfs/jbd. However since
I suppose a lot of disks flush everything pending on a flush cache
command it still works assuming the file systems write the 
data to disk in fsync before syncing the journal. I don't know
if they do that.

-Andi
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