better UDF support from GSoC 2012

[avg]

Summary

The new UDF driver does not replace the existing one right away,
but will co-exist with it as "udf2" for some time.

The code is based on
https://socsvn.freebsd.org/socsvn/soc2012/oleksandr/udf-head@240301

There are some post-GSoC fixes.
There seems to stll be a bug with files larger than 4 GB.

The GSoC work was sponsored by Google.
The work was done by Oleksandr Dudinskyi.
His work builds upon earlier work by
Will DeVries <[e-mail]>: https://github.com/williamdevries/UDF
The original code was written for NetBSD by Reinoud Zandijk <[e-mail]>.

Test Plan

I've been using this driver locally from time to time.

[kib]

Do you have specific questions to me, perhaps about something related to vfs interfaces usage ? Otherwise, I probably cannot provide much of useful feedback: I do not even know where to obtain udf spec. I more that happy to trust your judgement of the code compliance and its maturity for commit.

sys/fs/udf2/udf_readwrite.c

241

This is a huge disabled code block, with the nested disabled block. Is it needed in svn ?

259

Style: init in declaration.

270

tab before = is not style-compliant.

292

if (error != 0)

305

line too long

410

huge disabled block

780

and again.

781

please remove this ascii art.

[wblock]

sbin/mount_udf2/mount_udf2.8

29

Bump this.

48

"Attaches" sounds like a strange way of saying "mounts". Maybe this is consistent with other mount man pages, though.

56

This sentence is confusing. Does the unmount create remountable snapshots, or the close itself? Should there be a comma after "unmount"?

58

s/Note that this/This/

59

"DVD*R" is meant to be read as DVD-R or DVD+R, but this might not be clear to the reader. Better to be explicit:

recordable media like CD-R, DVD-R, and DVD+R.

61

s/of/for/

62

Simplify: `The default group is nobody.` However, I feel like the group name needs markup but do not know what to use.

66

"comma-separated"

69

s/man/manual/

70

These UDF-specific options are available:

80

This sentence is really unclear. Suggestion based on guesswork:

Select the
.Ar session
to be mounted.
The default is the last session on the disc.

81

s/Implements/This implements/
s/readonly/read-only/

89

As above with DVD*R.

101

s/file system/filesystem/

102

Rearrange for clarity:

UDF is a filesystem defined by the OSTA standardization group for optical discs
like CDs and DVDs to facilitate data interchange between different operating systems.

104

It has also become more common on other media like Compact

Do we really need to mention CF disks any more? How about

It can also be used on other types of media, like flash devices.

108

s/recognise/recognize/

[ae]

sys/fs/udf2/udf_vfsops.c

305

The vprint() function seems undefined.