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diff --git a/share/man/man9/g_attach.9 b/share/man/man9/g_attach.9 new file mode 100644 index 000000000000..4bf7d9c51493 --- /dev/null +++ b/share/man/man9/g_attach.9 @@ -0,0 +1,141 @@ +.\" +.\" Copyright (c) 2004 Pawel Jakub Dawidek <pjd@FreeBSD.org> +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR +.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES +.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. +.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, +.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT +.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF +.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +.\" +.\" $FreeBSD$ +.\" +.Dd January 16, 2004 +.Dt G_ATTACH 9 +.Os +.Sh NAME +.Nm g_attach , +.Nm g_detach +.Nd "attach/detach GEOM consumers to/from providers" +.Sh SYNOPSIS +.In geom/geom.h +.Ft int +.Fn g_attach "struct g_consumer *cp" "struct g_provider *pp" +.Ft void +.Fn g_detach "struct g_consumer *cp" +.Sh DESCRIPTION +The +.Fn g_attach +function attaches given consumer +.Fa cp +to given provider +.Fa pp , +thus establishing a communication channel between the consumer and the +provider that allows to change access counts and perform I/O operations. +.Pp +The +.Fn g_detach +function detaches given consumer +.Fa cp +from its corresponding provider, tearing down the communication channel +between them. +.Sh RESTRICTIONS/CONDITIONS +.Fn g_attach : +.Bl -item -offset indent +.It +The consumer must not be attached to a provider. +.It +The operation must not create a topology loop. +.It +The topology lock has to be held. +.El +.Pp +.Fn g_detach : +.Bl -item -offset indent +.It +The consumer has to be attached. +.It +The access count has to be 0. +.It +There must be no active requests. +.It +The topology lock has to be held. +.El +.Sh RETURN VALUES +The +.Fn g_attach +function returns 0 if successful; otherwise an error code is returned. +.Sh EXAMPLES +Create a consumer, attach it to a given provider, gain read access and clean up. +.Bd -literal -offset indent +void +some_function(struct g_geom *mygeom, struct g_provider *pp) +{ + struct g_consumer *cp; + + g_topology_assert(); + + /* Create new consumer on 'mygeom' geom. */ + cp = g_new_consumer(mygeom); + /* Attach newly created consumer to given provider. */ + if (g_attach(cp, pp) != 0) { + g_destroy_consumer(cp); + return; + } + /* Open provider for reading through our consumer. */ + if (g_access(cp, 1, 0, 0) != 0) { + g_detach(cp); + g_destroy_consumer(cp); + return; + } + + g_topology_unlock(); + /* + * Read data from provider. + */ + g_topology_lock(); + + /* Disconnect from provider (release access count). */ + g_access(cp, -1, 0, 0); + /* Detach from provider. */ + g_detach(cp); + /* Destroy consumer. */ + g_destroy_consumer(cp); +} +.Ed +.Sh ERRORS +Possible errors: +.Bl -tag -width Er +.It Bq Er ELOOP +The operation creates a topology loop. +.El +.Sh SEE ALSO +.Xr geom 4 , +.Xr DECLARE_GEOM_CLASS 9 , +.Xr g_access 9 , +.Xr g_bio 9 , +.Xr g_consumer 9 , +.Xr g_data 9 , +.Xr g_event 9 , +.Xr g_geom 9 , +.Xr g_provider 9 , +.Xr g_provider_by_name 9 , +.Xr g_wither_geom 9 +.Sh AUTHORS +.An -nosplit +This manual page was written by +.An Pawel Jakub Dawidek Aq pjd@FreeBSD.org . |