On Fri, Jan 22, 2010 at 10:30 AM, Thomas Kupper <tho...@kupper.org> wrote: > > On 22 Jan 2010, at 10:17, Leszek Ciesielski wrote: > >> On Fri, Jan 22, 2010 at 10:06 AM, Thomas Kupper <tho...@kupper.org> wrote: >>> >>> On 22 Jan 2010, at 09:59, Leszek Ciesielski wrote: >>> >>>> On Fri, Jan 22, 2010 at 12:55 AM, Thomas Kupper <tho...@kupper.org> wrote: >>>>> Using btrfs as the root filesystem on my Ubuntu 9.10 powered laptop I >>>>> discoverd that mount is not showing the actual passed rootflags= but >>>>> shows what is put in the /etc/fstab. >>>>> >>>>> First of all, I'm not sure if that is an intended behavior and if not, if >>>>> it's a problem of mount or btrfs. >>>>> >>>>> Example: >>>>> Following Goffredo's example there's a subvolume called rootfs which is - >>>>> surprisingly ;) - the root of the linux. The corresponding line in fstab >>>>> is >>>>> >>>>> $ cat /etc/fstab >>>>> [...] >>>>> # / was on /dev/sda3 during installation >>>>> UUID=<some-scary-UUID> / btrfs subvol=rootfs 0 1 >>>>> >>>>> $ mount >>>>> [...] >>>>> /dev/sda3 on / type btrfs (rw,subvol=rootfs) >>>>> >>>>> I create a snapshot of the rootfs called rootfs-snap-001 and create it in >>>>> the / of the btrfs volume itself. Not modifying grub2, I just edit grub >>>>> on the go. While booting I edit the /linux-kernel... entry and replace >>>>> rootflags=subvol=rootfs with rootflags=subvol=rootfs-snap-001. That boots >>>>> up just fine but the mount output still is >>>>> >>>>> $ mount >>>>> [...] >>>>> /dev/sda3 on / type btrfs (rw,subvol=rootfs) >>>>> >>>>> ... and /etc/mtab is indeed >>>>> >>>>> $ cat /etc/mtab >>>>> [...] >>>>> /dev/sda3 / btrfs rw,subvol=rootfs 0 0 >>>>> >>>>> shouldn't mount and /etc/mtab reflect the parameters in use? >>>>> >>>> >>>> No. The same thing happens with whatever filesystem you use for rootfs. >>> >>> Thanks for the clarification. How do I see then what subvolume is mounted >>> as root? Assume I play around with lots of snapshots and wonder with what >>> snapshot I booted. Sure, I should know but sometimes I want to make sure I >>> did boot the right one before deleting an other snapshot. >> >> azazel ~ # cat /proc/cmdline >> root=/dev/sda3 rootfstype=ext4 > > Again, thanks alot. That does the trick. > > Maybe a bit of a pain in the a$#: Is there a specific reason the mount > utility doesn't show the actual mount options in use? Wouldn't one - I > certainly do - expect /etc/mtab or mount to show how a certain partition is > mounted? Not really a btrfs issue, I'm aware.
Doesn't 'cat /proc/mounts' show the actually used mount options? -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
