Question on exFAT filesystem support

Hi Eason,

I think, you can use extFS support in SD/USB etc., not through NAND flash.

You have to cross compile the "fuse-exfat" (mount support) and "extfs-utils" packages to support "extFS".

Try the below link to enable extFS support in kernel.

https://github.com/dorimanx/exfat-nofuse

Hi Eason,

EXT filesystem doesn't support journaling fs and "power loss safe".

JFFS2,YAFFS2,UBIFS are the filesystems used in flash memory devices such as NAND, NOR, etc.,

EXT fs is used in eMMC/SD/MMC/HDD etc., which is doesn't care about power loss. ex: Desktop based

Refer to the below link.

http://www.micron.com/~/media/Documents/Products/Software%20Article/SWNL_choosing_linux_fs_for_flash.pdf

Chapter "Sector-Based Read/Write File Systems" and "Power Loss Tolerance"

Hi Eason,

I'm able to enable "extFS" support in liunux kernel and able to mount (pendrive) too.

Steps:

1) Download the "exFAT" moudule linux driver from the below link.

https://github.com/dorimanx/exfat-nofuse

2) Modify the "Makefile" as per your kernel source.

3) Build with your tollchain

4) Install the "exFAT" driver in linux.

Build Log:

titus@Titus:~/workdir/ti-e2e/exfat-nofuse-master$ make ARCH=arm CROSS_COMPILE=arm-arago-linux-gnueabi-
make -C /opt/ti/mcsdk_1_01_00_01/board-support/linux-3.3-psp03.22.00.06.sdk M=/home/titus/workdir/ti-e2e/exfat-nofuse-master modules
make[1]: Entering directory `/opt/ti/mcsdk_1_01_00_01/board-support/linux-3.3-psp03.22.00.06.sdk'
  CC [M]  /home/titus/workdir/ti-e2e/exfat-nofuse-master/exfat_core.o
  CC [M]  /home/titus/workdir/ti-e2e/exfat-nofuse-master/exfat_super.o
  CC [M]  /home/titus/workdir/ti-e2e/exfat-nofuse-master/exfat_api.o
  CC [M]  /home/titus/workdir/ti-e2e/exfat-nofuse-master/exfat_blkdev.o
  CC [M]  /home/titus/workdir/ti-e2e/exfat-nofuse-master/exfat_cache.o
  CC [M]  /home/titus/workdir/ti-e2e/exfat-nofuse-master/exfat_data.o
  CC [M]  /home/titus/workdir/ti-e2e/exfat-nofuse-master/exfat_bitmap.o
  CC [M]  /home/titus/workdir/ti-e2e/exfat-nofuse-master/exfat_nls.o
  CC [M]  /home/titus/workdir/ti-e2e/exfat-nofuse-master/exfat_oal.o
  CC [M]  /home/titus/workdir/ti-e2e/exfat-nofuse-master/exfat_upcase.o
  LD [M]  /home/titus/workdir/ti-e2e/exfat-nofuse-master/exfat.o
  Building modules, stage 2.
  MODPOST 1 modules
  CC      /home/titus/workdir/ti-e2e/exfat-nofuse-master/exfat.mod.o
  LD [M]  /home/titus/workdir/ti-e2e/exfat-nofuse-master/exfat.ko
make[1]: Leaving directory `/opt/ti/mcsdk_1_01_00_01/board-support/linux-3.3-psp03.22.00.06.sdk'
titus@Titus:~/workdir/ti-e2e/exfat-nofuse-master$

Makefile:

#
# Makefile for Linux FAT12/FAT16/FAT32(VFAT)/FAT64(ExFAT) filesystem driver.
#

ifneq ($(KERNELRELEASE),)
# call from kernel build system

obj-$(CONFIG_EXFAT_FS) += exfat.o

exfat-objs := exfat_core.o exfat_super.o exfat_api.o exfat_blkdev.o exfat_cache.o \
			   exfat_data.o exfat_bitmap.o exfat_nls.o exfat_oal.o exfat_upcase.o

else
# external module build

EXTRA_FLAGS += -I$(PWD)

#
# KDIR is a path to a directory containing kernel source.
# It can be specified on the command line passed to make to enable the module to
# be built and installed for a kernel other than the one currently running.
# By default it is the path to the symbolic link created when
# the current kernel's modules were installed, but
# any valid path to the directory in which the target kernel's source is located
# can be provided on the command line.
#
#KDIR	:= /lib/modules/$(shell uname -r)/build
KDIR	:= /opt/ti/mcsdk_1_01_00_01/board-support/linux-3.3-psp03.22.00.06.sdk
MDIR	:= /usr/local/filesystem_omapl138/lib/modules/$(shell uname -r)
PWD	:= $(shell pwd)
KREL	:= $(shell cd ${KDIR} && make -s kernelrelease)
MDIR	:= /usr/local/filesystem_omapl138/lib/modules/${KREL}
PWD	:= $(shell pwd)

export CONFIG_EXFAT_FS := m

all:
	$(MAKE) -C $(KDIR) M=$(PWD) modules

clean:
	$(MAKE) -C $(KDIR) M=$(PWD) clean

help:
	$(MAKE) -C $(KDIR) M=$(PWD) help

install: exfat.ko
	rm -f ${MDIR}/kernel/fs/exfat/exfat.ko
	install -m644 -b -D exfat.ko ${MDIR}/kernel/fs/exfat/exfat.ko
	depmod -aq

uninstall:
	rm -rf ${MDIR}/kernel/fs/exfat
	depmod -aq

endif

.PHONY : all clean install uninstall

Log:

root@omapl138-lcdk:/# cat /proc/filesystems
nodev   sysfs
nodev   rootfs
nodev   bdev
nodev   proc
nodev   cgroup
nodev   tmpfs
nodev   debugfs
nodev   sockfs
nodev   pipefs
nodev   anon_inodefs
nodev   rpc_pipefs
nodev   devpts
        ext3
        ext2
        cramfs
nodev   ramfs
        vfat
        msdos
        iso9660
nodev   nfs
        ufs
nodev   jffs2
nodev   mqueue
nodev   mtd_inodefs
nodev   ubifs
root@omapl138-lcdk:/#
root@omapl138-lcdk:/#
root@omapl138-lcdk:/#
root@omapl138-lcdk:/# insmod exfat.ko
exFAT: Version 1.2.9
root@omapl138-lcdk:/#
root@omapl138-lcdk:/# cat /proc/filesystems
nodev   sysfs
nodev   rootfs
nodev   bdev
nodev   proc
nodev   cgroup
nodev   tmpfs
nodev   debugfs
nodev   sockfs
nodev   pipefs
nodev   anon_inodefs
nodev   rpc_pipefs
nodev   devpts
        ext3
        ext2
        cramfs
nodev   ramfs
        vfat
        msdos
        iso9660
nodev   nfs
        ufs
nodev   jffs2
nodev   mqueue
nodev   mtd_inodefs
nodev   ubifs
        exfat
root@omapl138-lcdk:/# usb 1-1: new full-speed USB device number 2 using ohci
usb 1-1: not running at top speed; connect to a high speed hub
scsi1 : usb-storage 1-1:1.0
scsi 1:0:0:0: Direct-Access     Generic  Mass Storage     1.00 PQ: 0 ANSI: 2
sd 1:0:0:0: Attached scsi generic sg0 type 0
sd 1:0:0:0: [sda] 16179200 512-byte logical blocks: (8.28 GB/7.71 GiB)
sd 1:0:0:0: [sda] Write Protect is off
sd 1:0:0:0: [sda] Asking for cache data failed
sd 1:0:0:0: [sda] Assuming drive cache: write through
sd 1:0:0:0: [sda] Asking for cache data failed
sd 1:0:0:0: [sda] Assuming drive cache: write through
 sda: sda1
sd 1:0:0:0: [sda] Asking for cache data failed
sd 1:0:0:0: [sda] Assuming drive cache: write through
sd 1:0:0:0: [sda] Attached SCSI removable disk

root@omapl138-lcdk:/#
root@omapl138-lcdk:/#
root@omapl138-lcdk:/# mountFAT-fs (sda): bogus number of reserved sectors
FAT-fs (sda): Can't find a valid FAT filesystem
[EXFAT] trying to mount...
 [EXFAT] FsMountVol failed

rootfs on / type rootfs (rw)
/dev/root on / type ext3 (rw,relatime,errors=continue,user_xattr,barrier=1,data=writeback)
proc on /proc type proc (rw,relatime)
tmpfs on /mnt/.splash type tmpfs (rw,relatime,size=40k)
sysfs on /sys type sysfs (rw,relatime)
none on /dev type tmpfs (rw,relatime,size=1024k,nr_inodes=8192,mode=755)
/dev/mmcblk0p2 on /media/mmcblk0p2 type ext3 (rw,relatime,errors=continue,user_xattr,barrier=1,data=writeback)
/dev/mmcblk0p1 on /media/mmcblk0p1 type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=cp437,iocharset=iso8859-1,shortname=mixed,e)
/dev/mmcblk0p3 on /media/mmcblk0p3 type ext3 (rw,relatime,errors=continue,user_xattr,barrier=1,data=writeback)
devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620)
tmpfs on /var/volatile type tmpfs (rw,relatime,size=16384k)
tmpfs on /dev/shm type tmpfs (rw,relatime,mode=777)
tmpfs on /media/ram type tmpfs (rw,relatime,size=16384k)
root@omapl138-lcdk:/# FAT-fs (sda1): bogus number of reserved sectors
FAT-fs (sda1): Can't find a valid FAT filesystem
[EXFAT] trying to mount...
[EXFAT] mounted successfully
nls_utf8: disagrees about version of symbol module_layout

root@omapl138-lcdk:/#
root@omapl138-lcdk:/#
root@omapl138-lcdk:/# mount
rootfs on / type rootfs (rw)
/dev/root on / type ext3 (rw,relatime,errors=continue,user_xattr,barrier=1,data=writeback)
proc on /proc type proc (rw,relatime)
tmpfs on /mnt/.splash type tmpfs (rw,relatime,size=40k)
sysfs on /sys type sysfs (rw,relatime)
none on /dev type tmpfs (rw,relatime,size=1024k,nr_inodes=8192,mode=755)
/dev/mmcblk0p2 on /media/mmcblk0p2 type ext3 (rw,relatime,errors=continue,user_xattr,barrier=1,data=writeback)
/dev/mmcblk0p1 on /media/mmcblk0p1 type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=cp437,iocharset=iso8859-1,shortname=mixed,e)
/dev/mmcblk0p3 on /media/mmcblk0p3 type ext3 (rw,relatime,errors=continue,user_xattr,barrier=1,data=writeback)
devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620)
tmpfs on /var/volatile type tmpfs (rw,relatime,size=16384k)
tmpfs on /dev/shm type tmpfs (rw,relatime,mode=777)
tmpfs on /media/ram type tmpfs (rw,relatime,size=16384k)
/dev/sda1 on /media/sda1 type exfat (rw,relatime,fmask=0022,dmask=0022,namecase=1,errors=remount-ro)
root@omapl138-lcdk:/# ls /media/sda1/
exfat_test.txt
root@omapl138-lcdk:/#
root@omapl138-lcdk:/# uname -a
Linux omapl138-lcdk 3.3.0 #13 PREEMPT Thu Aug 28 17:49:04 IST 2014 armv5tejl unknown
root@omapl138-lcdk:/#
root@omapl138-lcdk:/#
root@omapl138-lcdk:/#