On Thu, Dec 12, 2013 at 1:05 PM, Karel Zak <kzak@xxxxxxxxxx> wrote: > > [CC: kernel guys] > > On Wed, Dec 11, 2013 at 09:37:57AM -0500, Phillip Susi wrote: >> It seems that the kernel has a bug where it silently ignores the >> MS_RDONLY flag when creating a bind mount. mount issues a warning >> that the mount point appears to be read-write even though you >> requested read only. The reporter suggests a patch to automatically >> attempt to remount with MS_RDONLY before issuing this warning to work >> around the kernel bug. What do you think? > > I have it implemented, so > > mount --bind --read-only /mnt /mnt > > is interpreted as two requests (two mount(2) calls) > > mount --bind /mnt /mnt > mount -o remount,bind,ro /tmp > > it works as expected, but it does not work with MS_REC (recursive) > because kernel currently does not support > > MS_REMOUNT|MS_BIND|MS_REC|... > > it means that > > mount --rbind --read-only /mnt /mnt > > creates only top-level read-only mountpoint, the rest is unchanged. > > > Miklos would be possible to fix kernel to accept MS_REC for > MS_REMOUNT|MS_BIND|MS_RDONLY operation? Please. I really hate the current mount(2) API. It's a gigantic hack, and it's nearing the end of its life anyway due to flags running out. So instead of adding more hacks, I think it would be better to think about adding a couple of syscalls that have clearly defined semantics. Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe util-linux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
