On Wed, Sep 02, 2009 at 10:48:33AM -0400, Tom Vier wrote: > On Mon, Aug 24, 2009 at 06:07:39PM -0400, Theodore Tso wrote: > > Sure, agreed. But let's look a bit closer at what "async commit" > > really means. > > > > What ext3 and ext4 does by default is this: > > > > 1) Write data blocks required by data=ordered mode (if any) > > Shouldn't there be a write barrier after data blocks, so that the journal > blocks aren't written first? ie, mark the first journal block write with > barrier flag on. No, it doesn't matter, because the journal blocks are ignored until the commit block is written. So the order of the data blocks required by data=ordered mode, and the journal blocks are written can be freely reordered by the elevator and the hard drive without any risk of data integrity problems. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
