diff options
author | pjd <pjd@FreeBSD.org> | 2004-02-11 10:06:18 +0000 |
---|---|---|
committer | pjd <pjd@FreeBSD.org> | 2004-02-11 10:06:18 +0000 |
commit | dbc7255199dc5592095e7b60e310c520a91641bb (patch) | |
tree | 343cd26c39251e0b38b336e71722a99c8b1510da /share/man/man9/g_attach.9 | |
parent | d2298f1b5c0d5a034a5957fc6dd651a04fb8626f (diff) | |
download | FreeBSD-src-dbc7255199dc5592095e7b60e310c520a91641bb.zip FreeBSD-src-dbc7255199dc5592095e7b60e310c520a91641bb.tar.gz |
Added first part of GEOM kernel API manuals pages.
Documented function and macros are:
- DECLARE_GEOM_CLASS(),
- g_attach(),
- g_detach(),
- g_new_bio(),
- g_clone_bio(),
- g_destroy_bio(),
- g_new_consumer(),
- g_destroy_consumer(),
- g_read_data(),
- g_write_data(),
- g_post_event(),
- g_waitfor_event(),
- g_cancel_event(),
- g_new_geomf(),
- g_destroy_geom(),
- g_new_providerf(),
- g_destroy_provider(),
- g_error_provider(),
- g_provider_by_name(),
- g_wither_geom().
and more to come.
I want to thanks following people for help with those documents:
Slawek Zak <zaks@prioris.mini.pw.edu.pl>
Simon L. Nielsen <simon@FreeBSD.org>
Pieter de Boer <g.p.de.boer@st.hanze.nl>
and of course
Poul-Henning Kamp <phk@FreeBSD.org>
Reviewed by: phk, scottl
Approved by: phk, scottl (mentor)
Diffstat (limited to 'share/man/man9/g_attach.9')
-rw-r--r-- | share/man/man9/g_attach.9 | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/share/man/man9/g_attach.9 b/share/man/man9/g_attach.9 new file mode 100644 index 0000000..9ed77f0 --- /dev/null +++ b/share/man/man9/g_attach.9 @@ -0,0 +1,138 @@ +.\" +.\" 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 consumer to/from provider" +.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 to given provider. +For real provider access (ie. I/O operations), one still need to call the +.Fn g_access_rel +function on consumer to gain access to attached provider. +.Pp +The +.Fn g_detach +function detaches the given consumer from the corresponding provider. +This function is used when we do not want to communicate with the +provider anymore. +.Sh RESTRICTIONS/CONDITIONS +.Fn g_attach : +.Bl -item -offset indent +.It +The consumer can not be attached already. +.It +The operation should 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 +.Fn g_attach +returns the value 0 if successful; otherwise an error code is returned. +.Sh ERRORS +Possible errors: +.Bl -tag -width Er +.It Bq Er ELOOP +The operation creates a topology loop. +.El +.Sh EXAMPLES +Create consumer, attach it to 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); + if (cp == NULL) + return; + /* 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_rel(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_rel(cp, -1, 0, 0); + /* Detach from provider. */ + g_detach(cp); + /* Destroy consumer. */ + g_destroy_consumer(cp); +} +.Ed +.Sh SEE ALSO +.Xr DECLARE_GEOM_CLASS 9 , +.Xr geom 4 , +.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 . |