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)

10 files changed, 1473 insertions, 0 deletions

diff --git a/share/man/man9/DECLARE_GEOM_CLASS.9 b/share/man/man9/DECLARE_GEOM_CLASS.9
new file mode 100644
index 0000000..4972caa
--- /dev/null
+++ b/share/man/man9/DECLARE_GEOM_CLASS.9
@@ -0,0 +1,175 @@
+.\"
+.\" 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 DECLARE_GEOM_CLASS 9
+.Os
+.Sh NAME
+.Nm DECLARE_GEOM_CLASS
+.Nd "GEOM class declaration macro"
+.Sh SYNOPSIS
+.In geom/geom.h
+.Fn DECLARE_GEOM_CLASS "class" "mod_name"
+.Sh DESCRIPTION
+The
+.Fn DECLARE_GEOM_CLASS
+macro registers a GEOM class in GEOM.
+A GEOM class itself implements one particular kind of transformation.
+Typical examples are: MBR disk partition, BSD disklabel and RAID5 classes.
+.Fn DECLARE_GEOM_CLASS
+can be used both for compiled in and loaded as
+.Xr kld 4
+modules GEOM classes and it is the only official way for class registration.
+.Pp
+The arguments to
+.Fn DECLARE_GEOM_CLASS
+are:
+.Bl -inset -offset indent
+.It Em class
+is the
+.Vt g_class
+structure which describes a GEOM class.
+.It Em mod_name
+is a kernel module name (not a class name!).
+.El
+.Pp
+Structure
+.Vt g_class
+contains data describing the class.
+They are:
+.Bl -inset -offset indent
+.It Vt "const char *" Va name
+Class name.
+.It Vt "g_taste_t *" Va taste
+Pointer to function used for taste event handling.
+If it is
+.No non- Ns Dv NULL
+it is called in three situations:
+.Bl -dash -offset indent -compact
+.It
+On class activation, all existing providers are offered for tasting.
+.It
+When new provider is created it is offered for tasting.
+.It
+After last write access to a provider is closed it is offered for retasting
+(on first write open event
+.Dq spoil
+was sent).
+.El
+.It Vt "g_config_t *" Va config
+This field is not used anymore, its functionality was replaced by the
+.Va ctlreq
+field.
+.It Vt "g_ctl_req_t *" Va ctlreq
+Pointer to function used for handling events from userland applications.
+.It Vt "g_init_t *" Va init
+Pointer to function which is called right after class registration.
+.It Vt "g_fini_t *" Va fini
+Pointer to function which is called right before class deregistration.
+.It Vt "g_ctl_destroy_geom_t *" Va destroy_geom
+Pointer to a function which is called for every geom on class unload.
+If this field is not set, the class can not be unloaded.
+.El
+.Pp
+Only field
+.Fa name
+is required, the rest is optional.
+.Pp
+.Sh RESTRICTIONS/CONDITIONS
+In the
+.Vt g_class
+initialization one must use C99 initialization (just like in the example below).
+.Pp
+.Sh EXAMPLES
+Example class declaration.
+.Bd -literal -offset indent
+static struct geom *
+g_example_taste(struct g_class *mp, struct g_provider *pp,
+    int flags __unused)
+{
+	g_topology_assert();
+
+	[...]
+}
+
+static void
+g_example_ctlreq(struct gctl_req *req, struct g_class *cp,
+    char const *verb)
+{
+
+	[...]
+}
+
+static int
+g_example_destroy_geom(struct gctl_req *req, struct g_class *cp,
+    struct g_geom *gp)
+{
+
+	g_topology_assert();
+
+	[...]
+}
+
+static void
+g_example_init(struct g_class *mp)
+{
+
+	[...]
+}
+
+static void
+g_example_fini(struct g_class *mp)
+{
+
+	[...]
+}
+
+struct g_class example_class = {
+	.name = "EXAMPLE",
+	.taste = g_example_taste,
+	.ctlreq = g_example_ctlreq,
+	.init = g_example_init,
+	.fini = g_example_fini,
+	.destroy_geom = g_example_destroy_geom
+};
+
+DECLARE_GEOM_CLASS(example_class, g_example);
+.Ed
+.Sh SEE ALSO
+.Xr geom 4 ,
+.Xr g_attach 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 .
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 .
diff --git a/share/man/man9/g_bio.9 b/share/man/man9/g_bio.9
new file mode 100644
index 0000000..d602665
--- /dev/null
+++ b/share/man/man9/g_bio.9
@@ -0,0 +1,224 @@
+.\"
+.\" 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_bio 9
+.Os
+.Sh NAME
+.Nm g_new_bio ,
+.Nm g_clone_bio ,
+.Nm g_destroy_bio
+.Nd "bio controlling functions"
+.Sh SYNOPSIS
+.In sys/bio.h
+.In geom/geom.h
+.Ft "struct bio *"
+.Fn g_new_bio void
+.Ft "struct bio *"
+.Fn g_clone_bio "struct bio *bp"
+.Ft void
+.Fn g_destroy_bio "struct bio *bp"
+.Sh DESCRIPTION
+The
+.Fa bio
+structure is used by GEOM to describe I/O requests.
+Most important fields of
+.Fa struct bio
+are described below:
+.Bl -tag -width ".Va bio_attribute"
+.It Va bio_cmd
+I/O request number.
+There are four I/O requests available in GEOM:
+.Bl -tag -width BIO_GETATTR
+.It Dv BIO_READ
+Self explanatory.
+.It Dv BIO_WRITE
+Self explanatory.
+.It Dv BIO_DELETE
+Delete indicates that a certain range of data is no longer used and that
+it can be erased or freed as the underlying technology supports.
+Technologies like flash adaptation layers can arrange to erase the relevant
+blocks before they will become reassigned and cryptographic devices may
+want to fill random bits into the range to reduce the amount of data
+available for attack.
+.It Dv BIO_GETATTR
+Get attribute supports inspection and manipulation of out\-of\-band
+attributes on a particular provider or path.
+Attributes are named by ascii strings and are stored in the
+.Va bio_attribute
+field.
+.El
+.It Va bio_offset
+Offset into provider.
+.It Va bio_data
+Pointer to data buffer.
+.It Va bio_flags
+Available flags:
+.Bl -tag -width BIO_GETATTR
+.It Dv BIO_ERROR
+Request failed (error value is stored in
+.Va bio_error )
+field.
+.It Dv BIO_DONE
+Request finished.
+.It Dv BIO_FLAG1
+Avaliable for private use.
+.It Dv BIO_FLAG2
+Avaliable for private use.
+.El
+.It Va bio_error
+Error value when BIO_ERROR is set.
+.It Va bio_done
+Pointer to function which will be called on request finish.
+.It Va bio_driver1
+Private use by the callee (ie: the provider).
+.It Va bio_driver2
+Private use by the callee (ie: the provider).
+.It Va bio_caller1
+Private use by the caller (ie: the consumer).
+.It Va bio_caller2
+Private use by the caller (ie: the consumer).
+.It Va bio_attribute
+Attribute string for BIO_GETATTR request.
+.It Va bio_from
+Consumer to use for request (attached to provider stored in
+.Va bio_to
+field) (typically read\-only for a class).
+.It Va bio_to
+Destination provider (typically read\-only for a class).
+.It Va bio_length
+Request length in bytes.
+.It Va bio_completed
+Number of bytes completed, but they may not be completed from
+the front of the request.
+.It Va bio_children
+Number of bio clones (typically read\-only for a class).
+.It Va bio_inbed
+Number of finished bio clones.
+.It Va bio_parent
+Pointer to parent bio.
+.El
+.Pp
+The
+.Fn g_new_bio
+function allocates a new, empty
+.Vt bio
+structure.
+.Pp
+The
+.Fn g_clone_bio
+function allocates a new
+.Vt bio
+structure and copies those fields from the
+.Vt bio
+structure given as an argument to clone:
+.Va bio_cmd ,
+.Va bio_length ,
+.Va bio_offset ,
+.Va bio_data ,
+.Va bio_attribute .
+The field
+.Va bio_parent
+in clone is set to source
+.Vt bio
+and the field
+.Va bio_children
+in parent is increased.
+.Pp
+This function should be used for every request which enters through
+the provider of a particular geom and needs to be scheduled down.
+Proper order is:
+.Pp
+.Bl -enum -compact
+.It
+Clone
+.Vt "struct bio" .
+.It
+Modify the clone.
+.It
+Schedule the clone on its own consumer.
+.El
+.Pp
+The
+.Fn g_destroy_bio
+function kills the given
+.Vt bio
+structure.
+.Sh EXAMPLES
+Implementation of
+.Dq Dv NULL Ns \-transformation ,
+meaning that an I/O request is cloned and scheduled down without any
+modifications.
+Let's assume that field
+.Va ex_consumer
+in structure
+.Vt example_softc
+contains a consumer attached to the provider we want to operate on.
+.Bd -literal -offset indent
+void
+example_start(struct bio *bp)
+{
+	struct example_softc *sc;
+	struct bio *cbp;
+
+	sc = bp->bio_to->geom->softc;
+	if (sc == NULL) {
+		g_io_deliver(bp, ENXIO);
+		return;
+	}
+
+	/* Let's clone our bio request. */
+	cbp = g_clone_bio(bp);
+	if (cbp == NULL) {
+		g_io_deliver(bp, ENOMEM);
+		return;
+	}
+	cbp->bio_done = g_std_done;	/* Standard 'done' function. */
+
+	/* Ok, schedule it down. */
+	/*
+	 * The consumer can be obtained from
+	 * LIST_FIRST(&bp->bio_to->geom->consumers) as well,
+	 * if there is only one in our geom.
+	 */
+	g_io_request(cbp, sc->ex_consumer);
+}
+.Ed
+.Sh SEE ALSO
+.Xr DECLARE_GEOM_CLASS 9 ,
+.Xr geom 4 ,
+.Xr g_attach 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 .
diff --git a/share/man/man9/g_consumer.9 b/share/man/man9/g_consumer.9
new file mode 100644
index 0000000..17b6c11
--- /dev/null
+++ b/share/man/man9/g_consumer.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_consumer 9
+.Os
+.Sh NAME
+.Nm g_new_consumer ,
+.Nm g_destroy_consumer
+.Nd "GEOM consumers management"
+.Sh SYNOPSIS
+.In geom/geom.h
+.Ft "struct g_consumer *"
+.Fn g_new_consumer "struct g_geom *gp"
+.Ft void
+.Fn g_destroy_consumer "struct g_consumer *cp"
+.Sh DESCRIPTION
+The GEOM consumer is the backdoor through which a geom connects to
+another GEOM provider and through which I/O requests are sent.
+.Pp
+The
+.Fn g_new_consumer
+function creates a new consumer releated to geom
+.Fa gp .
+The consumer is unusable prior attaching to a provider and gaining access
+to it.
+To serve its purpose, the consumer has to be attached to a provider
+with the
+.Xr g_attach 9
+function.
+.Pp
+The
+.Fn g_destroy_consumer
+function destroys given consumer and cancels all related pending events.
+This function is the last stage of killing an unwanted consumer.
+.Pp
+.Sh RESTRICTIONS/CONDITIONS
+.Fn g_new_consumer :
+.Bl -item -offset indent
+.It
+The geom related to the created consumer must have the
+.Fa start
+and
+.Fa access
+fields defined.
+.It
+The topology lock has to be held.
+.El
+.Pp
+.Fn g_destroy_consumer :
+.Bl -item -offset indent
+.It
+The consumer can not be attached.
+.It
+The access count has to be 0.
+.It
+The topology lock has to be held.
+.El
+.Sh RETURN VALUES
+.Fn g_new_consumer
+returns a pointer to the newly created consumer or
+.Dv NULL
+if an error occured.
+.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_attach 9 ,
+.Xr g_bio 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 .
diff --git a/share/man/man9/g_data.9 b/share/man/man9/g_data.9
new file mode 100644
index 0000000..c274cef
--- /dev/null
+++ b/share/man/man9/g_data.9
@@ -0,0 +1,111 @@
+.\"
+.\" 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_data 9
+.Os
+.Sh NAME
+.Nm g_read_data ,
+.Nm g_write_data
+.Nd "read/write data through consumer"
+.Sh SYNOPSIS
+.In geom/geom.h
+.Ft "void *"
+.Fn g_read_data "struct g_consumer *cp" "off_t offset" "off_t length" "int *error"
+.Ft int
+.Fn g_write_data "struct g_consumer *cp" "off_t offset" "void *ptr" "off_t length"
+.Sh DESCRIPTION
+The
+.Fn g_read_data
+reads
+.Fa length
+bytes of data from a provider through attached consumer
+.Fa cp
+starting at offset
+.Fa offset .
+Memory for data is allocated inside
+.Fn g_read_data
+with
+.Fn g_malloc ,
+and should therefor be freed by the caller with the
+.Fn g_free
+function after use.
+If the operation fails, an error value will be stored in the
+.Fa error
+argument if it is not
+.Dv NULL .
+.Pp
+The
+.Fn g_write_data
+writes
+.Fa length
+bytes of data from address
+.Fa ptr
+starting at offset
+.Fa offset
+to a provider through the attached consumer
+.Fa cp .
+.Sh RESTRICTIONS/CONDITIONS
+Length of data should be a multiple of the sectorsize for the provider
+and less than or equal to
+.Dv DFLTPHYS
+.Dv ( DFLTPHYS is defined in
+.In sys/param.h ) .
+.Pp
+The topology lock must not be held.
+.Sh RETURN VALUES
+.Fn g_read_data
+returns a pointer to the read data or
+.Dv NULL
+if an error occured.
+In that case an error value is stored in the
+.Fa error
+argument unsless it is
+.Dv NULL .
+.Pp
+.Fn g_write_data
+returns the value 0 if successful; otherwise an error code is returned.
+.Sh ERRORS
+Possible errors:
+.Bl -tag -width Er
+.It Bq Er EIO
+Can not read data.
+.El
+.Sh SEE ALSO
+.Xr DECLARE_GEOM_CLASS 9 ,
+.Xr geom 4 ,
+.Xr g_attach 9 ,
+.Xr g_bio 9 ,
+.Xr g_consumer 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 .
diff --git a/share/man/man9/g_event.9 b/share/man/man9/g_event.9
new file mode 100644
index 0000000..04d62118
--- /dev/null
+++ b/share/man/man9/g_event.9
@@ -0,0 +1,179 @@
+.\"
+.\" 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_event 9
+.Os
+.Sh NAME
+.Nm g_post_event ,
+.Nm g_waitfor_event ,
+.Nm g_cancel_event
+.Nd "events management"
+.Sh SYNOPSIS
+.In geom/geom.h
+.Ft int
+.Fn g_post_event "g_event_t *func" "void *arg" "int flag" ...
+.Ft int
+.Fn g_waitfor_event "g_event_t *func" "void *arg" "int flag" ...
+.Ft void
+.Fn g_cancel_event "void *ref"
+.Sh DESCRIPTION
+The GEOM has its own event queue to inform classes about important things.
+The event queue can be also used by classes, mostly for running away
+from I/O path.
+Sleeping, heavy weight tasks, etc. are not permitted on I/O path and
+events are the cure to avoid such situations.
+.Pp
+The
+.Fn g_post_event
+function tells GEOM to call function
+.Fa func
+with argument
+.Fa arg
+from the event queue.
+The
+.Fa flag
+argument is a flag for
+.Xr malloc 9
+that should be used by GEOM.
+Only the flags
+.Dv M_WAITOK
+or
+.Dv M_NOWAIT
+can be used.
+The rest of the arguments are used as references.
+An event can be canceled by using any of given references as an
+argument to the
+.Fn g_cancel_event
+function.
+The list of references has to end with a
+.Dv NULL
+value.
+.Pp
+The
+.Fn g_waitfor_event
+function is a blocking version of the
+.Fn g_post_event
+function.
+It waits until the event is finished or canceled and then returns.
+.Pp
+The
+.Fn g_cancel_event
+function cancels event(s) identified by
+.Fa ref .
+Cancellation is equivalent to calling the requested function
+with requested arguments and argument
+.Fa flag
+set to
+.Dv EV_CANCEL .
+.Sh RESTRICTIONS/CONDITIONS
+.Fn g_post_event :
+.Bl -item -offset indent
+.It
+The argument
+.Fa flag
+has to be
+.Dv M_WAITOK
+or
+.Dv M_NOWAIT .
+.It
+The list of references has to end with a
+.Dv NULL
+value.
+.El
+.Pp
+.Fn g_waitfor_event :
+.Bl -item -offset indent
+.It
+The argument
+.Fa flag
+has to be
+.Dv M_WAITOK
+or
+.Dv M_NOWAIT .
+.It
+The list of references has to end with a
+.Dv NULL
+value.
+.It
+The
+.Fn g_waitfor_event
+function can not be called from an event, since doing so would result
+in a deadlock.
+.El
+.Sh RETURN VALUES
+.Fn g_post_event
+and
+.Fn g_waitfor_event
+returns the value 0 if successful; otherwise an error code is returned.
+.Sh ERRORS
+Possible errors for
+.Fn g_post_event
+function:
+.Bl -tag -width Er
+.It Bq Er ENOMEM
+There was insufficient memory.
+.El
+.Pp
+Possible errors for
+.Fn g_waitfor_event
+function:
+.Bl -tag -width Er
+.It Bq Er EAGAIN
+The event was canceled.
+.It Bq Er ENOMEM
+There was insufficient memory.
+.El
+.Sh EXAMPLES
+Example of a function called from the event queue.
+.Bd -literal -offset indent
+void
+example_event(void *arg, int flag)
+{
+
+	if (flag == EV_CANCEL) {
+		printf("Event with argument %p canceled.\\n", arg);
+		return;
+	}
+
+	printf("Event with argument %p called.\\n", arg);
+}
+.Ed
+.Sh SEE ALSO
+.Xr DECLARE_GEOM_CLASS 9 ,
+.Xr geom 4 ,
+.Xr g_attach 9 ,
+.Xr g_bio 9 ,
+.Xr g_consumer 9 ,
+.Xr g_data 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 .
diff --git a/share/man/man9/g_geom.9 b/share/man/man9/g_geom.9
new file mode 100644
index 0000000..febc55b
--- /dev/null
+++ b/share/man/man9/g_geom.9
@@ -0,0 +1,202 @@
+.\"
+.\" 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_geom 9
+.Os
+.Sh NAME
+.Nm g_new_geomf ,
+.Nm g_destroy_geom
+.Nd "geom management"
+.Sh SYNOPSIS
+.In geom/geom.h
+.Ft "struct g_geom *"
+.Fn g_new_geomf "struct g_class *mp" "const char *fmt" ...
+.Ft void
+.Fn g_destroy_geom "struct g_geom *gp"
+.Sh DESCRIPTION
+The geom (do not confuse
+.Dq geom
+with
+.Dq GEOM )
+is an instance of a GEOM class.
+For example: in a typical i386 FreeBSD system, there will be one geom
+of class MBR for each disk.
+The geom's name is not really important, it is only used in the XML
+dump and for debugging purposes.
+There can be many geoms with the same name.
+.Pp
+The
+.Fn g_new_geomf
+function creates a new geom, which will be an instance of the class
+.Fa mp .
+The geom name is created in a printf\-like way from the rest of the arguments.
+.Pp
+The
+.Fn g_destroy_geom
+function destroys the given geom imediately and cancels all related pending
+events.
+.Pp
+Structure
+.Vt g_geom
+contains fields, that should be set by the caller after geom creation, but before
+creating any providers or consumers related to this geom (not all are required):
+.Bl -inset -offset indent
+.It Vt "g_start_t *" Va start
+Pointer to a function used for I/O processing.
+.It Vt "g_spoiled_t *" Va spoiled
+Pointer to a function used for consumers spoiling.
+.It Vt "g_dumpconf_t *" Va dumpconf
+Pointer to a function used for configuration in XML format dumping.
+.It Vt "g_access_t *" Va access
+Pointer to a function used for access control.
+.It Vt "g_orphan_t *" Va orphan
+Pointer to a function used to inform about orphaned consumer.
+.It Vt "g_ioctl_t *" Va ioctl
+Pointer to a function used for handling ioctl requests.
+.It Vt "void *" Va softc
+Field for private use.
+.El
+.Sh RESTRICTIONS/CONDITIONS
+If you intend to use providers in this geom you must set field
+.Va start
+of your geom.
+.Pp
+If you are planning to use consumers in your geom you must set fields
+.Va orphan
+and
+.Va access
+for it.
+.Pp
+.Fn g_new_geomf :
+.Bl -item -offset indent
+.It
+Class
+.Fa mp
+must be valid (registered in GEOM).
+.It
+The topology lock has to be held.
+.El
+.Pp
+.Fn g_destroy_geom :
+.Bl -item -offset indent
+.It
+The geom can not posses any providers.
+.It
+The geom can not posses any consumers.
+.It
+The topology lock has to be held.
+.El
+.Sh RETURN VALUES
+.Fn g_new_geomf
+returns a pointer to the newly created geom or
+.Dv NULL
+if an error occured.
+.Sh EXAMPLES
+Create an example geom.
+.Bd -literal -offset indent
+static struct geom *
+g_example_start(struct bio *bp)
+{
+
+	[...]
+}
+
+static void
+g_example_orphan(struct g_consumer *cp)
+{
+
+	g_topology_assert();
+
+	[...]
+}
+
+static void
+g_example_spoiled(struct g_consumer *cp)
+{
+
+	g_topology_assert();
+
+	[...]
+}
+
+static void
+g_example_access(struct g_provider *pp, int dr, int dw, int de)
+{
+
+	[...]
+}
+
+static struct g_geom *
+create_example_geom(struct g_class *myclass)
+{
+	struct g_geom *gp;
+
+	g_topology_lock();
+	gp = g_new_geomf(myclass, "example_geom");
+	g_topology_unlock();
+	if (gp != NULL) {
+		gp->start = g_example_start;
+		gp->orphan = g_example_orphan;
+		gp->spoiled = g_example_spoiled;
+		gp->access = g_example_access;
+		gp->softc = NULL;
+	}
+
+	return (gp);
+}
+
+static int
+destroy_example_geom(struct g_geom *gp)
+{
+
+	g_topology_lock();
+	if (!LIST_EMPTY(&gp->provider) ||
+	    !LIST_EMPTY(&gp->consumer)) {
+		g_topology_unlock();
+		return (EBUSY);
+	}
+	g_destroy_geom(gp);
+	g_topology_unlock();
+
+	return (0);
+}
+.Ed
+.Sh SEE ALSO
+.Xr DECLARE_GEOM_CLASS 9 ,
+.Xr geom 4 ,
+.Xr g_attach 9 ,
+.Xr g_bio 9 ,
+.Xr g_consumer 9 ,
+.Xr g_data 9 ,
+.Xr g_event 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 .
diff --git a/share/man/man9/g_provider.9 b/share/man/man9/g_provider.9
new file mode 100644
index 0000000..5318b8a
--- /dev/null
+++ b/share/man/man9/g_provider.9
@@ -0,0 +1,144 @@
+.\"
+.\" 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_provider 9
+.Os
+.Sh NAME
+.Nm g_new_providerf ,
+.Nm g_destroy_provider ,
+.Nm g_error_provider
+.Nd "GEOM providers management"
+.Sh 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"
+.Sh DESCRIPTION
+The GEOM provider is the front gate at which a geom offers service.
+A provider is
+.Dq a disk\-like thing which appears in Pa /dev
+\- a logical disk in other words.
+All providers have three main properties: name, sectorsize and size.
+.Pp
+The
+.Fn g_new_providerf
+function creates a new provider and attaches it to geom
+.Fa gp .
+The provider name is created in a printf\-like way from the rest of
+the arguments.
+After creation, the provider is unusable, because
+.Fn g_new_providerf
+sets its error to
+.Er ENXIO .
+The function
+.Fn g_error_provider
+should be used to reset this error, but before it is called, two
+fields should be set in the provider structure:
+.Va mediasize
+and
+.Va sectorsize
+as well as other initialization things should be done first.
+.Pp
+The
+.Fn g_destroy_provider
+function destroys the given provider, cancels all related pending events and
+removes corresponding devfs entry.
+.Pp
+The
+.Fn g_error_provider
+function is used to set a provider error value.
+If it set to a nonzero value, all I/O requests will be denied,
+increasing its access count will not be possible (error
+.Fa error
+will be returned).
+.Sh RESTRICTIONS/CONDITIONS
+.Fn g_new_provider :
+.Bl -item -offset indent
+.It
+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 programmer error.
+.It
+The geom related to the created provider must have
+.Fa start
+field defined.
+.It
+The topology lock has to be held.
+.El
+.Pp
+.Fn g_destroy_provider :
+.Bl -item -offset indent
+.It
+No consumers have to be attached.
+.It
+The access count has to be 0.
+.It
+The topology lock has to be held.
+.El
+.Sh RETURN VALUES
+.Fn g_new_providerf
+returns a pointer to the newly created provider or
+.Dv NULL
+if an error occured.
+.Sh EXAMPLES
+Create an example provider, set its parameters and make it usable.
+.Bd -literal -offset indent
+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();
+	if (pp != NULL) {
+		pp->mediasize = 65536;
+		pp->sectorsize = 512;
+		g_error_provider(pp, 0);
+	}
+
+	return (pp);
+}
+.Ed
+.Sh SEE ALSO
+.Xr DECLARE_GEOM_CLASS 9 ,
+.Xr geom 4 ,
+.Xr g_attach 9 ,
+.Xr g_bio 9 ,
+.Xr g_consumer 9 ,
+.Xr g_data 9 ,
+.Xr g_event 9 ,
+.Xr g_geom 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 .
diff --git a/share/man/man9/g_provider_by_name.9 b/share/man/man9/g_provider_by_name.9
new file mode 100644
index 0000000..92a78b4
--- /dev/null
+++ b/share/man/man9/g_provider_by_name.9
@@ -0,0 +1,74 @@
+.\"
+.\" 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_provider_by_name 9
+.Os
+.Sh NAME
+.Nm g_provider_by_name
+.Nd "find provider with given name"
+.Sh SYNOPSIS
+.In geom/geom.h
+.Ft "struct g_provider *"
+.Fn g_provider_by_name "const char *name"
+.Sh DESCRIPTION
+The
+.Fn g_provider_by_name
+searches for a provider called
+.Fa name
+and returns the structure
+.Fa g_provider
+bound to it.
+Argument
+.Fa name
+should be a name, not a full path (ie.
+.Dq Pa da0 ,
+instead of
+.Dq Pa /dev/da0 ) .
+.Sh RESTRICTIONS/CONDITIONS
+The topology lock has to be held.
+.Sh RETURN VALUES
+.Fn g_provider_by_name
+returns a pointer to the provider called
+.Fa name
+or
+.Dv NULL
+if there is no such provider.
+.Sh SEE ALSO
+.Xr DECLARE_GEOM_CLASS 9 ,
+.Xr geom 4 ,
+.Xr g_attach 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_wither_geom 9
+.Sh AUTHORS
+.An -nosplit
+This manual page was written by
+.An Pawel Jakub Dawidek Aq pjd@FreeBSD.org .
diff --git a/share/man/man9/g_wither_geom.9 b/share/man/man9/g_wither_geom.9
new file mode 100644
index 0000000..390fb4d
--- /dev/null
+++ b/share/man/man9/g_wither_geom.9
@@ -0,0 +1,85 @@
+.\"
+.\" 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_wither_geom 9
+.Os
+.Sh NAME
+.Nm g_wither_geom
+.Nd "destroy geom and releated providers and consumers when you get a chance"
+.Sh SYNOPSIS
+.In geom/geom.h
+.Ft void
+.Fn g_wither_geom "struct g_geom *gp" "int error"
+.Sh DESCRIPTION
+The
+.Fn g_wither_geom
+function tells GEOM that geom
+.Fa gp
+is to be destroyed.
+GEOM sets an error for every provider related to the given geom (in
+orphan process) and waits for a chance to destroy the geom.
+If access count of any possessed consumer goes to 0, consumer will be
+detached and destroyed automatically.
+If last consumer attached to any possesed provider will be detached,
+provider will be destroyed.
+If there are no more providers nor consumers, the geom will be
+destroyed.
+.Pp
+This is an automatic
+.Dq garbage collect
+to avoid duplicated code in all classes.
+Before it is called, field
+.Va softc
+should be disposed off and set to
+.Dv NULL .
+Note that the
+.Fn g_wither_geom
+function gives no guarantee that geom will be immediately destroyed, mostly
+because access counts of corresponding consumers and providers may not be 0.
+That is why calling this function for every geom from given class is not enough
+to be sure that class can be unloaded.
+.Sh RESTRICTIONS/CONDITIONS
+The argument
+.Fa error
+must be nonzero.
+.Pp
+The topology lock has to be held.
+.Sh SEE ALSO
+.Xr DECLARE_GEOM_CLASS 9 ,
+.Xr geom 4 ,
+.Xr g_attach 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
+.Sh AUTHORS
+.An -nosplit
+This manual page was written by
+.An Pawel Jakub Dawidek Aq pjd@FreeBSD.org .