FFS writes to read-only mount

[David Cecil]

> I still don't feel too familiar with the code, so not sure if my
> comments are usable:) how-to-reproduce procedure would be the best of
> course... David, do you use something which can be considered
> non-standard, like snapshots?
>   

I had been renaming the name of the mirror and the root mount point in 
an effort to keep the explanations shorter and less confusing, but I 
won't do that any more.  The / partition is actually on "f" not "a", and 
the mirror is called "gmroots1" not gm0s1.

Something that might be of interest, from the output of mount (snipped 
for brevity):

# mount
/dev/mirror/gmroots1f on / (ufs, local, read-only, soft-updates)
devfs on /dev (devfs, local)

Yes, soft-updates are on for /, but I've seen this problem (same 
partition, same error code) when they have not been on. 

# bsdlabel /dev/mirror/gmroots1
# /dev/mirror/gmroots1:
8 partitions:
#        size   offset    fstype   [fsize bsize bps/cpg]
  a:    80325        0    4.2BSD     2048 16384  5024
  b:  4194304    80325      swap
  c: 74231135        0    unused        0     0         # "raw" part, 
don't edit
  d: 55738981  8483659    4.2BSD     2048 16384 28552
  e: 10008495 64222640    4.2BSD     2048 16384 28552
  f:  4209030  4274629    4.2BSD     2048 16384 28552

Regards,
Dave

-- 
Software Engineer
Secure and Mobile Connectivity
Nokia Enterprise Solutions
+61 7 5553 8307 (office)
+61 412 728 222 (cell)