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g_destroy_provider.9freebsd

BSD mandoc

NAME

g_new_providerf g_destroy_provider g_error_provider - GEOM providers management

SYNOPSIS

In geom/geom.h Ft struct g_provider * Fn g_new_providerf struct g_geom *gp const char *fmt ... Ft void Fn g_destroy_provider struct g_provider *pp Ft void Fn 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 Fn 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 Fn g_error_provider to reset the provider's error, which is initially set to Er ENXIO .

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

The Fn 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

Fn 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.

Fn 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 Fn 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_CLASS9, g_access9, g_attach9, g_bio9, g_consumer9, g_data9, g_event9, g_geom9, g_provider_by_name9, g_wither_geom9

AUTHORS

An -nosplit This manual page was written by An Pawel Jakub Dawidek Aq pjd@FreeBSD.org .