Re: [gentoo-user] Options null for ext4 as root fs

[Mick]

On Tuesday 28 December 2010 17:23:22 Paul Hartman wrote:
> On Tue, Dec 28, 2010 at 7:50 AM, Mick <michaelkintzios@×××××.com> wrote:
> > What is the meaning of Opts: (null) ?
>
> My guess is that it is showing the default mount options as stored in
> the partition's superblock (set by tune2fs -o xxxxx). You can view the
> current default mount options by using "tune2fs -l /dev/sda1" (or
> whatever your partition is). Options given on mount commandline (or in
> fstab) should override the superblock mount options.
>
> My dmesg shows (null) as yours does, and tune2fs shows me:
> Default mount options:    (none)

OK, same as mine.


> > All ext4 partitions were created with a number of options; e.g.
> >
> > Filesystem features:      has_journal ext_attr resize_inode dir_index
> > filetype needs_recovery extent flex_bg sparse_super large_file uninit_bg
> > dir_nlink extra_isize
>
> Those are characteristics of your filesystem but I don't think they
> are considered mount options in this context.

Yes, that's right, but they affect some mount options if the latter are 
explicitly set at fstab.


> You can view the actual mount options currently in use by doing  "cat
> /proc/mounts"
>
> In my fstab I have "defaults,noatime" for my rootfs and in
> /proc/mounts it shows as:
>
> /dev/root / ext4 rw,noatime,barrier=1,data=ordered 0 0
>
> which looks correct to me.


Same here:

/dev/root / ext4 rw,noatime,barrier=1,data=ordered 0 0

Is that all that is required for ext4?  Do we need to define anything else to 
take advantage of the various ext4 options (see below)?

http://www.mjmwired.net/kernel/Documentation/filesystems/ext4.txt#125
-- 
Regards,
Mick