On Fri, Apr 28, 2017 at 9:25 AM, Amir Goldstein <amir73il@xxxxxxxxx> wrote: > With all recent conclusions, do you see a reason to keep origin root fh? No, I'm quite happy if we don't :) > For snapshots I need just one thing - > Verify that origin.fh matches the lower of merge dir that was found by path. > The verification is very cheap (only encode the found dentry), so we may > do it in any configuration, just don't know how to act upon it. > > What to do in case verification fails may need configuration option. > For snapshots I need a 'strict' policy meaning that "stale lower" equals > "implicit opaque", but that will not do the right thing for copied layers case. > > The way I have it now in my snapshot patches is overload on the redirect_dir > mount option and add a value redirect_dir=fh. The build time and module > options are still boolean, but -o redirect_dir=fh sets config->redirect_dir=true > and config->redirect_fh=true. > config->redirect_fh can later be set to false if the prerequisite (samefs etc) > don't apply. > > I may need to separate the general ofs->redirect_fh capabiltiy from the mount > configuration (i.e. config->redirect_dir_fh or make > config->redirect_dir an enum). > > I could also add more policy options for redirect_dir, i.e.: > off - pre v4.10 compat > on - v4.10 compat (path only) > path - same as on, just to explicitly mention for when knowingly copying layers > fh - snapshot case, fh must be verified > auto - (the default?) best effort w.r.t lower dir renames - > lookup by path, verify fh, if fails try to lookup by fh, if fails use > path result anyway. > > I realize you prefer the "minimum configuration" policy, but I'm afraid we > are at a cross road of letting the user decide. No? Is this only about dirs though? For now I'd just add a "verify_lower" option defaulting to off and not expand "redirect_dir". That should take care of the snapshot case, right? The more complicated things can come later. Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
