[patch] ext4fs read only mode

[Pedro Giffuni]

Hello;

On Aug. 22 2010 Zheng Liu posted a patch to add read-only
support for ext4 extents in our ext2fs driver that was part
of his GSoC.

The ext2fs module has received many enhancements, mainly
to make it look and behave more like the base UFS1 and the
old patch doesn't apply anymore.

I updated the patch just cleaning up some things that are
not strictly necessary and adapting it to the underlying
changes.

http://people.freebsd.org/~pfg/patches/patch-ext2-extents

The patch should apply cleanly in both 10-current and 9-stable.
No review of this patch has been done, beyond compiling on
amd64, and I have no idea if it works at all.

AFAICT, there was no feedback on the original patch so I am
actually wondering if this feature is desired at all. I will be
glad to keep it around for a while and eventually update it
but committing it is not yet in the horizon until we see
more interest and at least some testing.

best regards,

Pedro.