Can not boot after r203503. Unable to open /dev/ada(1/2)p3 for writing

[Andrey V. Elsukov]

26.02.10, 14:47, "Paul Wootton" <paul at fletchermoorland.co.uk>:
>  I have an unusual problem. Last night I tried updating from my old-ish 
>  kernel/world to an up to date version. I had been using 202500-ish 
>  successfully. I can build and install the newer world and kernel fine, 
>  but when I reboot I get the following
>  
>  Trying to mount root from zfs:raid250/root
>  ZFS WARNING: Unable to open /dev/ada1p3 for writing (error=1). ZFS 
>  WARNING: Unable to open /dev/ada2p3 for writing (error=1). ROOT MOUNT ERROR.
>  If you have invalid mount options, reboot, and first try the following 
>  from the loader prompt:
>      set vfs.root.mountfrom.options=rw
>  and then remove the invalid options from /etc/fstab
>  loader variables:
>      vfs.root.mountfrom=zfs:raid250/root
>      vfs.root.mountfrom.options=rw

I had the same problem recently. I have ZFS-only 9.0-CURRENT-amd64.
First time when i had this problem was after I added linux_load="YES" in
/boot/loader.conf. :-) 
It was only change i made. So, i rebooted again and unload linux from 
boot prompt. And system boots fine. I tried again with linux.ko and it failed to
boot. After that i synced source tree and rebuild kernel. And after that it failed
to boot with and without linux. :-)
So, after that i booted from another disk and only thing that i did was:
# zpool import -R /mnt z
# gpart modify -l ZFS -i 3 ad4 (previous label was "zfs")
After that i can boot with and without linux.ko again. And I can't reproduce this bug again.

-- 
WBR, Andrey V. Elsukov