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” – 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 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
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 error will be returned).
RESTRICTIONS/CONDITIONS
- 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 gp has to have a start method defined.
- The topology lock has to be held.
- 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);
}
SEE ALSO
geom(4), DECLARE_GEOM_CLASS(9), g_access(9), g_attach(9), g_bio(9), g_consumer(9), g_data(9), g_event(9), g_geom(9), g_provider_by_name(9), g_wither_geom(9)
AUTHORS
This manual page was written by Pawel Jakub Dawidek <pjd@FreeBSD.org>.