Re: reiser4 plugins

Christoph Hellwig
2005-06-26T17:27:05Z

On Sun, Jun 26, 2005 at 09:07:00PM +0400, Artem B. Bityuckiy wrote:
> Just out of curiosity, could you please specify few exact examples with
> specific file/function names which duplicate the existing
> infrastructure. What do they duplicate and why? How should these
> functions be implemented on VFS? Ho should the the other FSes
> implement/ignore them? Why are you shure they will fit VFS well? etc.

Right now every file/inode/etc method in reiser4 is just a trivial
wrapper around a plugin call. It should instead just set the method
table directly in the plugin initialization. Example:

static int
reiser4_permission(struct inode *inode /* object */ ,
int mask, /* mode bits to check permissions
* for */
struct nameidata *nameidata)
{
/* reiser4_context creation/destruction removed from here,
because permission checks currently don't require this.

Permission plugin have to create context itself if necessary. */
assert("nikita-1687", inode != NULL);

return perm_chk(inode, mask, inode, mask);
}

besides a useless assert we just call into perm_chk, which is a macro
obsfucation to call generic_permission which would be called if
->permission was zero. A hypothetical reiser4 "plugin" that would need
redefine ->permission would just override it in a set inode_operations.