On Sun, Sep 14, 2008 at 09:47:11AM -0400, Christoph Hellwig wrote: > On Sat, Sep 13, 2008 at 02:49:24PM -0400, Theodore Ts'o wrote: > > +* FIEMAP_EXTENT_NO_BYPASS > > +Direct access to the data in this extent is illegal or will have > > +undefined results. > > This one is sitll misnamed and for sure utterly misdocumented. Direct > access to the data is always illegal and has undefined results, and > programs that do it anyway (e.g. grub) are in really deep trouble. Programs like Grub *have* to. And in the case of a boot-loader, Lilo and Grub have been able to do so safely for over 15 years. This is basically a generic flag that indicates that they can't, but it reflects the reality that for many filesystems, they *can*. The main legal use is LILO and/or Grub, in fact. One could argue that programs that try accessing data blocks directly while the filesystem is mounted are doomed, but boot loaders do so while the filesystem are unmounted. The name isn't particularly important, but what it indicates is very clearly useful. - Ted -- 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
