VFS modules - how do you referrence prev fd from open on first write

[troutb at abclabs.com]

VFS - modlues

I want to check the fd on my first write call to see if it just got opened
by write call or is a susequent write call.

The purpose is to preform a backup only if the user actually write data to
thefile.

I have been study the vfs.h, smb.h, skel.c to figure this out
fsp->prev->fd  cause the VFS module to crash!
I'm new to c and to write samba code....

I have been study the vfs.h, smb.h, skel.c to figure this out
can someone direct me to some additional info and/or docs on this subject
or anyother helpful insights

thanks