trace MKFS

Peter Teoh htmldeveloper at
Fri Jan 4 23:02:48 EST 2013

when u execute "mkfs", based on your "-t" filesystem passed in to mkfs, one
of the following command line utility will be executed:

mkfs.cramfs    mkfs.ext4      mkfs.minix     mkfs.reiserfs
mkfs.bfs       mkfs.ext2      mkfs.ext4dev   mkfs.msdos     mkfs.vfat
mkfs.btrfs     mkfs.ext3      mkfs.jfs       mkfs.ntfs      mkfs.xfs

and for each of the above command line there is a fs utility that include
it.   Look into the source for good understanding.   For ext2/ext3 fs, it
is called e2fsprogs. So in Ubuntu (or Debian-based distro) u do a "apt-get
source e2fsprogs" to get the source:

reading the source of mkfs's main() function:

u can see that after lots of code on setting structures in memory, it start
by writing the inode table etc:

write_inode_tables(fs, lazy_itable_init, itable_zeroed);
create_bad_block_inode(fs, bb_list);

Following through the source code is much more understandable than going
through output of "strace", which records all the interface with the kernel.

Follow through the following slide:

and forward a few slides and u will understand that mkfs is just making the
header structures on the harddisk to contain the definition of the FS :

Similarly u can find many university courses on filesystem internal, eg:

Generally, real-life analysis of the harddisk/filesystem is done in
forensic, so if u googling for fs forensics u can find lots of tools that
walk the harddisk for the different components:

and this is forensics of ext4 filesystem:

Understanding "mkfs", is really as good as understanding FS internals.

On Fri, Jan 4, 2013 at 11:12 PM, KASHISH BHATIA <
kashish.bhatia1989 at> wrote:

> Hi,
> I want to trace the overall flow of mkfs inside linux kernel. Specifically
> want to know which
> kernel fs data structures are affected when we run "mkfs" ?
> What all "mkfs" command writes on the block device when we run the
> command?
> Are there any good documents which can explain the same?
> --
> Regards,
> Kashish Bhatia
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at

Peter Teoh
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