On Tue, Sep 01, 2020 at 01:34:05PM +1000, Dave Chinner wrote: > > But, unlike your implication that this is -really complex and hard > to do-, it's actually relatively trivial to do with the XFS > implementation I mentioned as each ADS stream is a fully fledged > inode that can point to shared data extents. If you can do data > manipulation on a regular inode, you'll be able to do it on an ADS, > and that includes copying ADS streams via reflink. Is the reflink system call on a file with ADS's atomic, or not? What if there are a million files is ADS hierarchy which is 100 subdirectories deep in some places, comprising several TB's worth of data? Is that all going to fit in a single XFS transaction? What if you crash in the middle of it? Is a partially reflinked copy of an ADS file OK? Or a reflinked ADS file missing some portion of the alternate data streams? - Ted
