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g_provider (9)

>> g_provider (9) ( FreeBSD man: Ядро )

BSD mandoc

NAME



g_new_providerf

 
g_destroy_provider

 
g_error_provider

 - GEOM providers management

SYNOPSIS

#include <geom/geom.h>
struct g_provider * g_new_providerf (struct g_geom *gp const char *fmt ...);
void g_destroy_provider (struct g_provider *pp);
void g_error_provider (struct g_provider *pp int error);

DESCRIPTION

A GEOM provider is the front gate at which a geom offers service. A provider is ``a disk-like thing which appears in /dev '' [en] a logical disk in other words. All providers have three main properties: name, sectorsize and size.

The g_new_providerf ();
function creates a new provider on given geom Fa gp . The name of the provider, which will appear as device in devfs(5), is created in a printf(3) -like way from the rest of the arguments. After creation, the caller has to set the provider's mediasize and sectorsize as well as other desired initializations, and then call g_error_provider ();
to reset the provider's error, which is initially set to Er ENXIO .

The g_destroy_provider ();
function destroys the given provider, cancels all related pending events and removes the corresponding devfs entry.

The g_error_provider ();
function is used to set the provider's error value. If set to a nonzero, all I/O requests will be denied, as well as increasing its access count will not be possible (error Fa error will be returned).

RESTRICTIONS/CONDITIONS

g_new_provider (:);

The provider name should be unique, but this is not enforced by GEOM.: If the name is not unique, one will end up with two (or more) files with the same name, which is a programmer error.
The geom: Fa gp has to have a Fa start method defined.
The topology lock has to be held.

g_destroy_provider (:);

The provider must not have consumers attached.
The access count has to be 0.
The topology lock has to be held.

RETURN VALUES

The g_new_providerf ();
function returns a pointer to the newly created provider.

EXAMPLES

Create an example provider, set its parameters and make it usable.

struct g_provider *
create_example_provider(struct g_geom *gp)
{
        struct g_provider *pp;

        g_topology_lock();
        pp = g_new_providerf(gp, "example_provider");
        g_topology_unlock();
        pp->mediasize = 65536;
        pp->sectorsize = 512;
        g_error_provider(pp, 0);

        return (pp);
}