How to obtain file's inode in ufshcd driver

[Roman Storozhenko]

Hello everybody.

I am modifying ufshcd driver:
https://elixir.bootlin.com/linux/v3.8/source/drivers/scsi/ufs/ufshcd.c

I do a read of a file on ext4 filesystem and want to obtain the file's
inode. But it seems that there are no structures contatin any
references to inode at this level of abstraction.
I looked into scsi_cmd structure and all the structures it references
to. Also I used ftrace to find on which level of abstraction inode
disappear but without any luck. Could you please say to me where I
could find the lowest level where inode is still present and the best
way how to pass it throughout linux io stack to the ufshcd driver?
Frankly speaking I need not struct inode as a whole but just its
number, so using reserved or unused fields of existing structures is
appropriate.

-- 
Kind regards,
Roman