On Wed, Apr 30, hooanon05@xxxxxxxxxxx wrote: > > Hello Nagabhushan, > > bsn.0007@xxxxxxxxx: > > I went through Bharata's RFC post on glibc based Union Mount readdir solution > > (http://lkml.org/lkml/2008/3/11/34) and have come up with patches > > against glibc to implement the same. > ::: > > While I don't have objection against the implementation in userspace, > what will UnionMount handle about rmdir or rename dir? > Those systemcalls need to test whether the dir is *logically* empty or > not in kernel space, don't they? > And I am afraid that UnionMount has to implement the similar thing, but > it never mean to modify glibc is a bad idea. For rmdir it is simple: the filesystem that supports whiteouts must know how to get rid of them again. Since it knows how the whiteouts are implemented it can do that in an optimized fashion. The rename story is somehow different. A union directory consists of multiple directories on different filesystem. Since rename syscall is only working on one filesystem the rename is crossing devices. Therefore I return -EXDEV. Not very efficient but really simple. At least this is how my patches implement it. Regards, Jan -- Jan Blunck <jblunck@xxxxxxx> -- 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
