Handling a directory search

Handling a directory search

[Charles Manning]

Hi folks.

I'm tweaking the readdir handling for YAFFS and need to be able to manage a 
"directory search context" structure where I can stash the context. 

ie.

/* user prog  and corresponding YAFFS operation */

   opendir(..);   /* YAFFS needs to create a search context */

  readdir(...);   /* YAFFS needs to use the search context */

  closedir(...); /* YAFFS needs to release the search context */

I am unsure as to how to hook the opendir and closedir to create/release the 
directory search context. 

Any pointers?

First prize: Any examples?

Thanx

-- Charles








    

Re: Handling a directory search

[Charles Manning]

On Wednesday 08 February 2006 11:10, Charles Manning wrote:
> Hi folks.
>
> I'm tweaking the readdir handling for YAFFS and need to be able to manage a
> "directory search context" structure where I can stash the context.
>
> ie.
>
> /* user prog  and corresponding YAFFS operation */
>
>    opendir(..);   /* YAFFS needs to create a search context */
>
>   readdir(...);   /* YAFFS needs to use the search context */
>
>   closedir(...); /* YAFFS needs to release the search context */
>
> I am unsure as to how to hook the opendir and closedir to create/release
> the directory search context.
>
> Any pointers?
>
> First prize: Any examples?
>

I think I have found the answer, I'd like anyone to verify that I've got this 
straight.

The dir operations .open will be called during opendir, allowing me to hang a 
context off filp->private_data.

The dir operations .release will be called during the closedir allowing me to 
release the context.

Is that safe?

Are there any hungry wolves out there going to bite me if I work to the above?

Thanx

-- Charles

Re: Handling a directory search

[Tomas Hruby]

Hi,

> The dir operations .open will be called during opendir, allowing me to hang a
> context off filp->private_data.

If I am not wrong, e.g. EXT3 does it in readdir. It checks whether
filp->private_data == NULL and so decides if it is called for the
first time (because it is deallocated only in the .release)

We do the same in our fs.

Tomas