Passes usertests and stressfs
Seems to recover correctly in a number of simple cases

Variable declarations at top of function,
separate from initialization.

Use == 0 instead of ! for checking pointers.

Consistent spacing around {, *, casts.

Declare 0-parameter functions as (void) not ().

Integer valued functions return -1 on failure, 0 on success.

kinit() knows about end and PHYSTOP
map all of kernel read/write (rather than r/o instructions)
thanks, austin

nit in sbrk
indirect block
fix dup to share fd struct

mkdir
ls shows stat info for each dir entry

fix acquire() to cli() *before* incrementing nlock
make T_SYSCALL a trap gate, not an interrupt gate
sadly, various crashes if you hold down a keyboard key...

balloc

iget
mkfs makes a file system image
put this in your .bochsrc:
ata0-slave: type=disk, mode=flat, path="fs.img", cylinders=1024, heads=1, spt=1