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freebsd/sys/geom/geom_int.h
Alexander Motin 7f16b501e2 GEOM: Introduce partial confxml API
Traditionally the GEOM's primary channel of information from kernel to
user-space was confxml, fetched by libgeom through kern.geom.confxml
sysctl.  It is convenient and informative, representing full state of
GEOM in a single XML document.  But problems start to arise on systems
with hundreds of disks, where the full confxml size reaches many
megabytes, taking significant time to first write it and then parse.

This patch introduces alternative solution, allowing to fetch much
smaller XML document, subset of the full confxml, limited to 64KB and
representing only one specified geom and optionally its parents.  It
uses existing GEOM control interface, extended with new "getxml" verb.
In case of any error, such as the buffer overflow, it just transparently
falls back to traditional full confxml.  This patch uses the new API in
user-space GEOM tools where it is possible.

Reviewed by:	imp
MFC after:	2 month
Sponsored by:	iXsystems, Inc.
Differential Revision:	https://reviews.freebsd.org/D34529
2022-03-12 11:55:52 -05:00

79 lines
2.9 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 2002 Poul-Henning Kamp
* Copyright (c) 2002 Networks Associates Technology, Inc.
* All rights reserved.
*
* This software was developed for the FreeBSD Project by Poul-Henning Kamp
* and NAI Labs, the Security Research Division of Network Associates, Inc.
* under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
* DARPA CHATS research program.
*
* 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.
* 3. The names of the authors may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 AUTHOR OR CONTRIBUTORS 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.
*
* $FreeBSD$
*/
LIST_HEAD(class_list_head, g_class);
TAILQ_HEAD(g_tailq_head, g_geom);
extern int g_collectstats;
#define G_STATS_PROVIDERS 1 /* Collect I/O stats for providers */
#define G_STATS_CONSUMERS 2 /* Collect I/O stats for consumers */
/* geom_dump.c */
void g_confxml(void *, int flag);
void g_conf_specific(struct sbuf *sb, struct g_geom **gps);
void g_conf_cat_escaped(struct sbuf *sb, const char *buf);
void g_conf_printf_escaped(struct sbuf *sb, const char *fmt, ...);
void g_confdot(void *, int flag);
void g_conftxt(void *, int flag);
/* geom_event.c */
void g_event_init(void);
void g_run_events(void);
void g_do_wither(void);
/* geom_subr.c */
extern struct class_list_head g_classes;
extern char *g_wait_event, *g_wait_up, *g_wait_down;
void g_wither_washer(void);
/* geom_io.c */
void g_io_init(void);
void g_io_schedule_down(struct thread *tp);
void g_io_schedule_up(struct thread *tp);
/* geom_kern.c / geom_kernsim.c */
void g_init(void);
extern struct thread *g_up_td;
extern struct thread *g_down_td;
extern int g_shutdown;
extern int g_notaste;
/* geom_ctl.c */
void g_ctl_init(void);