On Fri, Dec 15, 2017 at 4:18 PM, Miklos Szeredi <miklos@xxxxxxxxxx> wrote: > On Thu, Dec 14, 2017 at 5:29 PM, Amir Goldstein <amir73il@xxxxxxxxx> wrote: >> On Thu, Dec 14, 2017 at 5:48 PM, Miklos Szeredi <miklos@xxxxxxxxxx> wrote: [...] >>> >>>> Exporting index is a challenge for the same reason and also because tar can >>>> break hardlinks on extract. Probably index should be rebuilt from scratch on >>>> import, based on "redirect". >>> >>> Yes, hard links need special handling, so will metacopy. Might be >>> worth adding "redirect" to hard links and metacopy to make this issue >>> less of a problem. >>> >> >> Do you mean add it now in kernel? hmm, that's just another thing that >> can become inconsistent, so I don't see the immediate value. > > The immediate value is that no need for a special pack/unpack tool for > transferring the overlay "image". > OK, but I don't see how we can escape unpack tool for rebuilding the index from redirects. Do you mean that you want to also follow non-dir "redirect"? Resolve conflicts between "redirect" and "origin"? Fix "redirect" by "origin"? fix "origin" by redirect"? I am all for that. Already have patches to fix "redirect" by "origin" for dirs: https://github.com/amir73il/linux/commits/ovl-redirect-fix >> >> Which reminds me, you did not provide feedback to the patch I posted >> to detect duplicate redirect dir use case: >> >> https://marc.info/?l=linux-unionfs&m=151126880100432&w=2 >> >> Do you consider this a bug that should be detected by overlayfs >> as patch proposed or leave it to be detected only when enabling >> opt-in directory indexing (named verify=on in current WIP patches)? >> >> Also waiting for your feedback about merging the duplicate redirect dir >> test case to xfstests: >> https://marc.info/?l=fstests&m=151149994629687&w=2 >> >> Bug or not bug? > > Hmm... I'd lean towards non-bug. That "offline modification is > allowed" rule should point out caveats when messing with overlay > specific attributes (opaque, whiteout, redirect, etc). Obviously > having two redirects pointing to the same underlying dir is going to > result in inconsistencies. We can get away with it without constant > ino, but I don't think it makes sense to allow that construct. > I also think that allowing user to mess with trusted.overlay xattr is not fair play. The test I posted however, doesn't do that. The test does cp -a of a redirected upper dir. Something that perhaps user could get away with before redirect_dir and something that an innocent user may be doing. Anyway, directories index lookup takes care of duplicate redirect problem as a by product of NFS export: https://github.com/amir73il/linux/commit/b1dd6461aa7c26091aad7c9b65c04cc1071bb9e0 Amir. -- 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
