On Tue, 19 May 2009, Jan Blunck wrote: > The directory in the topmost filesystem is created during > lookup. The contents of the directory isn't copied up presistently > at that point in time. Therefore you have an empty directory in the > topmost filesystem after the lookup. This was necessary to get rid > of the union_relookup_topmost() calls during create, mknod, mkdir > etc. > > When readdir is called, the topmost directory is filed up with > fallthru entries which are persistently stored. This is only > necessary to get readdir right wrt POSIX. During lookup the fallthru > dentry, which is in fact a special negative dentry, is ignored and > therefore the lookup continues on the lower filesystem. So this means that the topmost branch always needs to be writable, right? It isn't possible to make a union of two iso9660 filesystems, for example? Thanks, Miklos -- 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
