On Tue, Mar 22, 2016 at 05:52:32PM -0400, J. Bruce Fields wrote: > On Wed, Mar 23, 2016 at 08:29:31AM +1100, Dave Chinner wrote: > > If you want additional seekable data streams, then come up with a > > filesystem namespace method of addressing these alternate data > > streams as *separate files containing data*. That's all an ADS is - > > a namespace hack to address multiple data files through a single > > file name. That's the problem that needs solving and it has nothing > > to do with xattrs. > > There was some thread about this years ago. Looking... "silent semantic > changes with reiser4" or "possible design issues for hybrids" look like > the relevant threads. > > One good starting point might be: > > http://mid.gmane.org/20040826212853.GA21964@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx > > Don't know how out of date that might be now. Not sure it is the same issue - that looks like auto-bind-mount stuff. There are some relevant questions though, like "directory over file" semantics and implications... But we have covered this ground before, and at LSF/MM summits, too. historically it has been made pretty clear that xattrs are not something that can be used for alternate data streams. I think ADS is primarily a namespace and API problem - that needs to be sorted out first, and then what filesytems need to implement will be obvious. Perhaps overlayfs is a good place to start prototyping such functionality as there is an abstraction between the presented namespace and the underlying storage of the data.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
