On Wed, Mar 20, 2013 at 03:41:08PM -0400, George Spelvin wrote: > Sorry for being so very late to the party, but rather than messing > with xattrs, why not just have a specific file (say, default /.whiteout, > but selectable via a mount option) and links to it are counted as > whiteout entries? > > All you need to do is resolve the link (it's probably a good idea > to allow symlinks to avoid hard-link count limits) and compare the > fs and inode number. > > It's kind of hackish, but it could be done on pretty much *any* Unix > file system. VFAT would be SOL, but that's probably acceptable. > > (Any security options on mount point crossing or consistent ownership > of symlinks that you want to impose would probably be of general VFS > use, and again, not FS-specific.) Yeah... Now, think what rm -rf foo/ would be doing. We read the underlying directory. For each file in it we create a link to that magical file of yours in covering one. _Then_ we do rmdir(), and what a joy it turns out to be - we * lock the covering directory * read the covering directory and stat everything in it, checking that it's a link to your file; we also read the underlying directory and verify that everything in it has a matching whiteout in the covering one. * once we are through, we read it *again*, this time doing unlinks and praying real hard we won't crash in the meanwhile * once that is finished, we finally can rmdir the fucker and unlock its inode. I'm sorry, but this is insane. -- 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
