Miklos Szeredi <mik...@szeredi.hu> wrote: > Regarding whiteouts, I raised a couple of questions that nobody answered > yet, so let me ask again. > > - If a filesystem containing whiteouts (fallthroughs, etc...) is mounted as > not part of a union, how are these special entities represented to > userspace?
I would suggest that whiteouts appear as otherwise negative dentries and that they don't appear in getdents(). Fallthroughs are far more 'interesting'. Maybe they should appear in getdents() with a dentry type saying what they are, but give you EREMOTE or something if you try to follow them. Note that there is space in d_flags & DCACHE_ENTRY_TYPE for a whiteout type. I would, however, mark fallthroughs by a separate flag. So that the union dentry will mirror the source dentry's type. > - Can the user remove them? Overwriting whiteouts and fallthroughs and unlinking fallthroughs I don't see as a problem where they can be treated as normal negative dentries and normal files in this regard. However, what do you do about non-opaque directories that may or may not have been unioned if you try and follow a dirent that would be a subdirectory that hasn't been copied up? David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
