Re: GOP_ALLOC vs VOP_FALLOCATE

[Chuck Silvers <chuq%chuq.com@localhost>]

On Wed, Sep 24, 2014 at 01:33:08PM +0200, Emmanuel Dreyfus wrote:
> Hi
> 
> Is there a real difference between GOP_ALLOC and VOP_FALLOCATE? The two
> operation seem very similar, with just extra flag and cred args for
> GOP_ALLOC. 

VOP_* calls are part of the interface between a file system and the rest of the kernel.
they may be called on any vnode (though calls that aren't implemented will return an error).

the GOP_* calls are only to be used internal to the implementation of a file system.
they are an interface between a file system implementation and some bits of the genfs code.
the fs calls genfs, and the GOP_* calls allow the genfs code to call back into the specific fs code.
unless you're writing a new fs, you should not use these.

-Chuck