Failed to mount filesystem about simplefs HOT 1 OPEN

On Thu, Nov 12, 2015 at 10:33:39AM -0800, Shubajit Saha wrote:

I tried to mount the file system after inserting the simplefs kernel module. But it is giving error while initializing journal block. The dmesg report is given below.
kernel version: 3.13.0-32-generic

[24820.367435] The magic number obtained in disk is: [268640275]
[24820.367440] simplefs filesystem of version [1] formatted with a block size of [4096] detected in the device.
[24820.367465] jbd2_journal_bmap: journal block not found at offset 0 on loop0-2
[24820.367466] jbd2_journal_init_inode: Cannot locate journal superblock
[24820.367469] Can't load journal

How are you creating journal+fs?

I guess that you don't created correct journal, you can use the
following commands to do this (copied from simple-test.sh, and slightly
edited):
$ function create_journal()
{
dd bs=1M count=10 if=/dev/zero of="$1"
mke2fs -b 4096 -O journal_dev "$1"
}
$ function create_test_image()
{
dd bs=4096 count=100 if=/dev/zero of="$1"
./mkfs-simplefs "$1"
}
$ function mount_fs_image()
{
insmod simplefs.ko
test_journal_dev=$(losetup -f --show "$1")
mount -o loop,owner,group,users,journal_path="$test_journal_dev" -t simplefs "$2" "$3"
}
$ create_test_image image
$ create_journal journal
$ mount_fs_image journal image /mnt

from simplefs.