My changes have a race with re-used bufs and the code doesn't seem to get shorter
Keep the changes that fixed ip->off race

This reverts commit 3a5fa7ed.

Conflicts:

	defs.h
	file.c
	file.h

Remove I_BUSY, B_BUSY, and intrans defs and usages
One spinlock per buf to avoid ugly loop in bget
fix race in filewrite (don't update f->off after releasing lock)

Invoke initlog from forkret on first user process

Switch back to #define for PHYSTOP.  Using the E820 to retrieve the memory map is too complicated (must be done in 16-bit real-mode, probably enlarged bootblock beyond 512 bytes, and a #define requires less explanation).

Get rid of last instances of linear address and "la"
Get ready for detecting physical memory dynamically

2011

Without this, every write to the console results in log writes.

Maybe the string boot shouldn't appear in xv6 code?

usertest for big write()s
push begin_trans/commit_trans down into syscalls

Remove device mapping from bootpgdir
Remove unnecessary vmenable
Set CPUS back to 2 in Makefile
Passes all usertests