Panic on mount with write-locked USB media (umass)

[Poul-Henning Kamp]

In message <20050405201820.042685D07 at ptavv.es.net>, "Kevin Oberman" writes:

>> It would be useful if mount was smart enough to notice when it is 
>> dealing with a read-only device, and try to mount such things 
>> read-only, rather than trying to mount things read-write by default and 
>> failing.  Of course, the system shouldn't panic, either.  :-)
>
>I think that is what I said. I am almost sure that this is how it used
>to work. I'm not sure whether the change was caused by something in
>msdosfs or GEOM (or somewhere else), but I sure preferred it when the RO
>device mounted RO. CDs still do this (thankfully). This makes me suspect
>msdosfs is the culprit.

There are two ways that a filesystem correctly could handle a R/O
media:

1.	Fail with EROFS unless asked t mouned read-only

2.	Silently downgrade th emount to read-only.

I personally prefer the first because that way a script does not
have to check if it got the mount it wanted or not.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.