README

#
# Copyright 2016, NICTA
#
# This software may be distributed and modified according to the terms of
# the GNU General Public License version 2. Note that NO WARRANTY is provided.
# See "LICENSE_GPLv2.txt" for details.
#
# @TAG(NICTA_GPL)
#

How to compile BilbyFs?

# Tested with linux-3.18.22. Similar versions should work.

Linux:

1 Download linux sources from <https://www.kernel.org/> and decompress it,
  then `cd` to the target folder

2 run `make menuconfig` and add MTD, UBI, etc as modules.

3 run `make prepare && make modules_prepare` in the linux sources directory

4 run `export KERNELDIR=path/of/linux/sources`

5 run `make` either in the c/ directory to build bilbyfs.ko,
  or in the cogent/ directory to build cgbilbyfs.ko.

Limitations:

- There is no mkfs for BilbyFs. When mounting BilbyFs for the first time, if
  the flash is empty, the in-kernel module (both C and Cogent versions) will
  automatically format the flash with BilbyFs format.
- The Cogent and C version of BilbyFs use a slightly different on-flash format.
  We cannot mount a file system formatted with C version with the Cogent version
  and vice versa.
- BilbyFs Cogent on-flash garbage collector is not implemented, so currently it
  does not recycle obsolete parts of the log.
- The Cogent code can sometimes run out of stack space, hence it's recommended
  to increase the kernel stack size to run Cogent BilbyFs.

# Running on a Simulated NAND disc:

  modprobe nandsim first_id_byte=0xec second_id_byte=0xd3 third_id_byte=0x51 fourth_id_byte=0x95
  modprobe ubi
  ubiformat /dev/mtd0
  ubiattach /dev/ubi_ctrl -m 0
  ubimkvol /dev/ubi0 -N bilby -s 956MiB
  ubiupdatevol /dev/ubi0_0 -t

  insmod bilbyfs.ko
  mkdir -p /mnt/disk
  mount -t bilbyfs ubi0:bilby /mnt/disk