changes to Ken's file server to make this 63-bit file server

               Geoff Collyer
               July—October 2004

note: 2⁶³=9,223,372,036,854,775,808 or 8EB (9.2×10¹⁸)

• identified longs that refer to offsets, sizes and block numbers, and
changed them to type Off (vlong); fixed all print formats to match.
fixed byte-swapping for the 'x' config to match.

• fixed VLONG 9p1 message packing and unpacking macros to actually
handle 64-bit offsets and sizes.

• implemented triple-indirect blocks.  affected code in
       dev/cw.c        port/con.c      port/dentry.c   port/sub.c
       port/chk.c      port/console.c  port/portdat.h

• Fri Aug  6 16:50:59 PDT 2004
       ; ./sizes
       Plan 9 v4 63-bit file server
               sizeof(Dentry) = 124
               sizeof(Cache)  =  88

• added long(er) file name components (56 bytes), long enough for all but one
 name in my /.longnames file (68-byte .xml name).

• Fri Aug  6 21:43:41 PDT 2004
       ; ./sizes
       Plan 9 v4 63-bit file server sizes
               sizeof(Dentry) = 160
               sizeof(Cache)  =  88

• touched up lib.h (from libc.h) to bring it up to date with formatting
 functions, verbs & flags.
• check now reports stack usage: 320 bytes upon entry to fsck first time,
 92 bytes of stack per recursion.  given 16000 bytes of stack,
 that's 170 recursions maximum.
• booted xtc (terminal) from fs64 (used fs64 as main file system)

note: current file server with triple-indirect blocks at 4k block size
       has a maximum file size of ~505GB (5.42×10¹¹).
       with quadruple-indirect blocks, max would be ~275TB @ 4k block size.

• got igbe fs driver working (a couple small changes)
• eliminated some gotos (started with 580, down to 454)
• added quadruple indirect blocks: lets us reach 2⁶³ with a 32kB block size
• got igbe boot driver & pxe booting working
• on-disk qid paths are now Offs, but 9p1 qids on the wire are still ulongs
• generalised & parameterised indirect block implementation
• tested with plain w0 fs, cached fake worm on w0, cw jukebox (hp 160fx)
• ip directories in fs & fs64 are identical except for whitespace and
 goto-elimination
• replaced most of nemo's ide code with newer ide code lifted from 9load,
 then from cpu kernel (sdata.c & support).  this brings us dma, rwm & lba48,
 finds ide controllers by itself, even pci ones, & copes with dead drives
 (i.e., doesn't panic).
• fixed long-standing bug that caused a 5-second delay before each console
 prompt on systems without a serial console.
• further type parameterisation: Userid (short), Timet (long), Devsize (vlong).
   Comment on v7 kernel portability work, quoting scj & dmr from BSTJ v57
   #6 part 2., p. 2038: ``The important data types used within the
   system were identified and specified using typedef: disk offsets,
   absolute times, internal device names, and the like.  This effort was
   carried out by K. Thompson.''
• corrected compat.h dependencies in mkfiles
• eliminated all warnings
• implemented truncation via wstat