F9: fsck gotcha on booting

[Todd Denniston]

Patrick O'Callaghan wrote, On 04/21/2008 11:35 PM:
> On Mon, 2008-04-21 at 20:32 -0700, Andrew Farris wrote:
>> Patrick O'Callaghan wrote:
>>> My fstab contains the line:
>>>
>>> LABEL=/xtra             /xtra                   ext3    defaults        1 2
>>>
>>> which worked fine on F8. Now with F9-Preview the boot process halts with
>>> the following error (I'm working form memory here):
>>>
>>> 	Fsck: cannot resolve "LABEL=/xtra"
>>>
>>> and drops me to a Shell to fix the problem. Two things:
>>>
>>> 1) From the Shell I can happily "mount /xtra" with no problems, so what
>>> gives?
>>>
>>> 2) I can't edit /etc/fstab from this Shell. "mount" claims that the
>>> system disk is mounted rw. but when I try to edit fstab "vi" tells me
>>> it's read-only, and in fact "> foo" from the Shell gives the same error.
>>> So I feel I have to ask why is the emergency Shell set up to not let me
>>> edit anything?
>> Did you try editing then using w! to save it?  That may have worked.
> 
> Of course. It didn't. w! is fine if it's just a write-protected file.
> This was a read-only filesystem.
> 
> poc
> 

when in faulted file system mode, trust /proc/mounts instead of /etc/mtab 
(which is what mount returns data from).

a trick for when you need to write to these file systems:
mount -oremount,rw /mountpoint
i.e., for the root file system
mount-oremount,rw /

-- 
Todd Denniston
Crane Division, Naval Surface Warfare Center (NSWC Crane)
Harnessing the Power of Technology for the Warfighter