After hot power-off => "mount: error mounting /dev/root on /sysroot as ext3:"

直接将Fedora电源关闭后，开机显示如题错误，在以下网址：http://forums.fedoraforum.org/showthread.php?s=32fd71ba95033d14b52f4ec56ea1eb58&t=227417

找到solution如下：

 

This is not a question but a solution.
I have encountered this problem twice on Fedora-10.

When surfing the web, due to some strange issue unknown to me, the Fedora-10 (or the Firefox, rather) would hang (mostly video/MP3 playback), and freeze the entire screen 
(even the Crtl-Alt-Del does nothing).
The only option left was to power it off (I know, bad alternative) and on again.
It happened to me twice that this following message shows up during reboot.

"mount: error mounting /dev/root on /sysroot as ext3: No such file or directory"
(and the reboot hangs there forever!)

note: the Fedora-10 has been working fine prior to the hot power-off.

I searched the web (inc. this forum) and found solutions that do not apply to this situation.
The same problem could be a result of upgrading FC versions. Not in my/this case.

Therefore, I thought it maybe a good idea to post it here so that the next guy don't have to
scratch his/her head wondering why and how...

The remedy is simple.
- pop in the rescue disk into optical drive (when the error happens)
- reboot (by ctrl-alt-del)
- select "Rescue Installed System" (follow the prompt until the rescue shell shows up)
- (do nothing in the rescue shell since no setting needs to be changed)
- pop out the rescue disk from optical drive
- exit rescue shell by typing "exit" - it automatically reboots
You will see that the problem goes away.

My guess is that while the Fedora-10 hangs, it could happen the disk mounting was left in a wrong state when the hot shutdown (poweroff) is triggered. 
Thus, the reboot couldn't get pass it. (This was very common on old Solaris OS)
By bringing up the rescue shell, the bad state is corrected. Subsequent reboot will work properly.

It took me 2 days trying to fix it myself (by searching the web etc.) for the 1st time.
It only took me 1 minute the second time (today).

So, I hope this helps some people someday.
Cheers,