[Buildroot] readonly rootfs problem

[Buildroot] readonly rootfs problem

[Ed Sutter]

Hi,
I've been using buildroot to create my rootfs for a few months.
I build my kernel directly out of freescale.git.
I had been running with my rootfs nfs mounted, and all was well.
Recently I had spent some time with a ramdisk-based rootfs because
i was working on some kernel stuff.
Now I'm going back to running rootfs/nfs and I'm finding that
it "insists" on coming up in read-only mode.

I was initially using buildroot-2013.08, and recently I
updated to buildroot-2013.11; however, I don't think that has
anything to do with this.  As far as I can tell I have everything
set up properly...

####On NFS host /etc/exports has...
/full_path_to_my_rootfs *(rw,no_root_squash)

####On target...
/etc/inittab...
null::sysinit:/bin/mount -o remount,rw / # REMOUNT_ROOTFS_RW

/etc/fstab...
# /etc/fstab: static file system information.
#
# <file system> <mount pt>     <type> <options>         <dump> <pass>
/dev/root       /              ext2     rw,noauto         0      1
proc            /proc          proc     defaults          0      0
devpts          /dev/pts       devpts   defaults,gid=5,mode=620 0      0
tmpfs           /dev/shm       tmpfs    mode=0777         0      0
tmpfs           /tmp           tmpfs    defaults          0      0
sysfs           /sys           sysfs    defaults          0 0

Output from mount:
# mount
rootfs on / type rootfs (rw)
1.2.3.4:/full_path_to_my_rootfs on / type nfs 
(ro,relatime,vers=3,rsize=4096,wsize=4096,namlen=255,hard,nolock,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=1.2.3.4,mountvers=3,mountproto=tcp,local_lock=all,addr=135.222.138.108)
devtmpfs on /dev type devtmpfs 
(rw,relatime,size=110708k,nr_inodes=27677,mode=755)
proc on /proc type proc (rw,relatime)
devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw,relatime,mode=777)
tmpfs on /tmp type tmpfs (rw,relatime)
sysfs on /sys type sysfs (rw,relatime)

I actually think the problem is in the kernel, not the rootfs.
I say this because even some of my older rootfs copies (still on my 
host) are now
showing up as read only.  The bootlog always ends up with this message:
VFS: Mounted root (nfs filesystem) readonly on device 0:11.

Any idea what I might be doing wrong here?
Thanks,
Ed

[Buildroot] readonly rootfs problem

[Baruch Siach]

Hi Ed,

On Mon, Mar 03, 2014 at 05:14:47PM -0500, Ed Sutter wrote:
> I've been using buildroot to create my rootfs for a few months.
> I build my kernel directly out of freescale.git.
> I had been running with my rootfs nfs mounted, and all was well.
> Recently I had spent some time with a ramdisk-based rootfs because
> i was working on some kernel stuff.
> Now I'm going back to running rootfs/nfs and I'm finding that
> it "insists" on coming up in read-only mode.
> 
> I was initially using buildroot-2013.08, and recently I
> updated to buildroot-2013.11; however, I don't think that has
> anything to do with this.  As far as I can tell I have everything
> set up properly...
> 
> ####On NFS host /etc/exports has...
> /full_path_to_my_rootfs *(rw,no_root_squash)
> 
> ####On target...
> /etc/inittab...
> null::sysinit:/bin/mount -o remount,rw / # REMOUNT_ROOTFS_RW
> 
> /etc/fstab...
> # /etc/fstab: static file system information.
> #
> # <file system> <mount pt>     <type> <options>         <dump> <pass>
> /dev/root       /              ext2     rw,noauto         0      1
> proc            /proc          proc     defaults          0      0
> devpts          /dev/pts       devpts   defaults,gid=5,mode=620 0      0
> tmpfs           /dev/shm       tmpfs    mode=0777         0      0
> tmpfs           /tmp           tmpfs    defaults          0      0
> sysfs           /sys           sysfs    defaults          0 0
> 
> Output from mount:
> # mount
> rootfs on / type rootfs (rw)
> 1.2.3.4:/full_path_to_my_rootfs on / type nfs (ro,relatime,vers=3,rsize=4096,wsize=4096,namlen=255,hard,nolock,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=1.2.3.4,mountvers=3,mountproto=tcp,local_lock=all,addr=135.222.138.108)
> devtmpfs on /dev type devtmpfs
> (rw,relatime,size=110708k,nr_inodes=27677,mode=755)
> proc on /proc type proc (rw,relatime)
> devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620)
> tmpfs on /dev/shm type tmpfs (rw,relatime,mode=777)
> tmpfs on /tmp type tmpfs (rw,relatime)
> sysfs on /sys type sysfs (rw,relatime)
> 
> I actually think the problem is in the kernel, not the rootfs.
> I say this because even some of my older rootfs copies (still on my
> host) are now
> showing up as read only.  The bootlog always ends up with this message:
> VFS: Mounted root (nfs filesystem) readonly on device 0:11.
> 
> Any idea what I might be doing wrong here?

What happens if you manually run:

	mount -o remount,rw /

Do you see any error message?

baruch

-- 
     http://baruch.siach.name/blog/                  ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -

[Buildroot] readonly rootfs problem

[Ed Sutter]

On 3/4/2014 1:18 AM, Baruch Siach wrote:
> Hi Ed,
>
> On Mon, Mar 03, 2014 at 05:14:47PM -0500, Ed Sutter wrote:
>> I've been using buildroot to create my rootfs for a few months.
>> I build my kernel directly out of freescale.git.
>> I had been running with my rootfs nfs mounted, and all was well.
>> Recently I had spent some time with a ramdisk-based rootfs because
>> i was working on some kernel stuff.
>> Now I'm going back to running rootfs/nfs and I'm finding that
>> it "insists" on coming up in read-only mode.
>>
>> I was initially using buildroot-2013.08, and recently I
>> updated to buildroot-2013.11; however, I don't think that has
>> anything to do with this.  As far as I can tell I have everything
>> set up properly...
>>
>> ####On NFS host /etc/exports has...
>> /full_path_to_my_rootfs *(rw,no_root_squash)
>>
>> ####On target...
>> /etc/inittab...
>> null::sysinit:/bin/mount -o remount,rw / # REMOUNT_ROOTFS_RW
>>
>> /etc/fstab...
>> # /etc/fstab: static file system information.
>> #
>> # <file system> <mount pt>     <type> <options>         <dump> <pass>
>> /dev/root       /              ext2     rw,noauto         0      1
>> proc            /proc          proc     defaults          0      0
>> devpts          /dev/pts       devpts   defaults,gid=5,mode=620 0      0
>> tmpfs           /dev/shm       tmpfs    mode=0777         0      0
>> tmpfs           /tmp           tmpfs    defaults          0      0
>> sysfs           /sys           sysfs    defaults          0 0
>>
>> Output from mount:
>> # mount
>> rootfs on / type rootfs (rw)
>> 1.2.3.4:/full_path_to_my_rootfs on / type nfs (ro,relatime,vers=3,rsize=4096,wsize=4096,namlen=255,hard,nolock,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=1.2.3.4,mountvers=3,mountproto=tcp,local_lock=all,addr=135.222.138.108)
>> devtmpfs on /dev type devtmpfs
>> (rw,relatime,size=110708k,nr_inodes=27677,mode=755)
>> proc on /proc type proc (rw,relatime)
>> devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620)
>> tmpfs on /dev/shm type tmpfs (rw,relatime,mode=777)
>> tmpfs on /tmp type tmpfs (rw,relatime)
>> sysfs on /sys type sysfs (rw,relatime)
>>
>> I actually think the problem is in the kernel, not the rootfs.
>> I say this because even some of my older rootfs copies (still on my
>> host) are now
>> showing up as read only.  The bootlog always ends up with this message:
>> VFS: Mounted root (nfs filesystem) readonly on device 0:11.
>>
>> Any idea what I might be doing wrong here?
> What happens if you manually run:
>
> 	mount -o remount,rw /
>
> Do you see any error message?
>
> baruch
>
Thanks for responding, yea I've tried that (it fails).
Here's the output:
# mount -o remount,rw /
mount: mounting 1.2.3.4:/full_path_to_my_rootfs on / failed: Invalid 
argument

[Buildroot] readonly rootfs problem

[Ed Sutter]

On 3/4/2014 1:18 AM, Baruch Siach wrote:
> Hi Ed,
>
> On Mon, Mar 03, 2014 at 05:14:47PM -0500, Ed Sutter wrote:
>> I've been using buildroot to create my rootfs for a few months.
>> I build my kernel directly out of freescale.git.
>> I had been running with my rootfs nfs mounted, and all was well.
>> Recently I had spent some time with a ramdisk-based rootfs because
>> i was working on some kernel stuff.
>> Now I'm going back to running rootfs/nfs and I'm finding that
>> it "insists" on coming up in read-only mode.
>>
>> I was initially using buildroot-2013.08, and recently I
>> updated to buildroot-2013.11; however, I don't think that has
>> anything to do with this.  As far as I can tell I have everything
>> set up properly...
>>
>> ####On NFS host /etc/exports has...
>> /full_path_to_my_rootfs *(rw,no_root_squash)
>>
>> ####On target...
>> /etc/inittab...
>> null::sysinit:/bin/mount -o remount,rw / # REMOUNT_ROOTFS_RW
>>
>> /etc/fstab...
>> # /etc/fstab: static file system information.
>> #
>> # <file system> <mount pt>     <type> <options>         <dump> <pass>
>> /dev/root       /              ext2     rw,noauto         0      1
>> proc            /proc          proc     defaults          0      0
>> devpts          /dev/pts       devpts   defaults,gid=5,mode=620 0      0
>> tmpfs           /dev/shm       tmpfs    mode=0777         0      0
>> tmpfs           /tmp           tmpfs    defaults          0      0
>> sysfs           /sys           sysfs    defaults          0 0
>>
>> Output from mount:
>> # mount
>> rootfs on / type rootfs (rw)
>> 1.2.3.4:/full_path_to_my_rootfs on / type nfs (ro,relatime,vers=3,rsize=4096,wsize=4096,namlen=255,hard,nolock,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=1.2.3.4,mountvers=3,mountproto=tcp,local_lock=all,addr=135.222.138.108)
>> devtmpfs on /dev type devtmpfs
>> (rw,relatime,size=110708k,nr_inodes=27677,mode=755)
>> proc on /proc type proc (rw,relatime)
>> devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620)
>> tmpfs on /dev/shm type tmpfs (rw,relatime,mode=777)
>> tmpfs on /tmp type tmpfs (rw,relatime)
>> sysfs on /sys type sysfs (rw,relatime)
>>
>> I actually think the problem is in the kernel, not the rootfs.
>> I say this because even some of my older rootfs copies (still on my
>> host) are now
>> showing up as read only.  The bootlog always ends up with this message:
>> VFS: Mounted root (nfs filesystem) readonly on device 0:11.
>>
>> Any idea what I might be doing wrong here?
> What happens if you manually run:
>
> 	mount -o remount,rw /
>
> Do you see any error message?
>
> baruch
>
Just got it...
This error started after I updated my kernel, and apparently the new kernel
does not default to a rw nfs-mounted rootfs, so I had to add "rw" to the
kernel command line.
Thanks,
Ed