146 lines
4.0 KiB
C
146 lines
4.0 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#include <sys/param.h>
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#include <sys/bio.h>
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#include <sys/kernel.h>
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#include <sys/limits.h>
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#include <sys/malloc.h>
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#include <sys/queue.h>
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#include <sys/sysctl.h>
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#include <sys/systm.h>
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#include <geom/geom.h>
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#define G_ZERO_CLASS_NAME "ZERO"
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static int g_zero_clear_sysctl(SYSCTL_HANDLER_ARGS);
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SYSCTL_DECL(_kern_geom);
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static SYSCTL_NODE(_kern_geom, OID_AUTO, zero, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
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"GEOM_ZERO stuff");
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static int g_zero_clear = 1;
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SYSCTL_PROC(_kern_geom_zero, OID_AUTO, clear,
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CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, &g_zero_clear, 0,
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g_zero_clear_sysctl, "I",
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"Clear read data buffer");
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static int g_zero_byte = 0;
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SYSCTL_INT(_kern_geom_zero, OID_AUTO, byte, CTLFLAG_RW, &g_zero_byte, 0,
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"Byte (octet) value to clear the buffers with");
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static struct g_provider *gpp;
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static int
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g_zero_clear_sysctl(SYSCTL_HANDLER_ARGS)
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{
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int error;
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error = sysctl_handle_int(oidp, &g_zero_clear, 0, req);
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if (error != 0 || req->newptr == NULL)
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return (error);
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if (gpp == NULL)
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return (ENXIO);
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if (g_zero_clear)
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gpp->flags &= ~G_PF_ACCEPT_UNMAPPED;
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else
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gpp->flags |= G_PF_ACCEPT_UNMAPPED;
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return (0);
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}
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static void
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g_zero_start(struct bio *bp)
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{
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int error = ENXIO;
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switch (bp->bio_cmd) {
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case BIO_READ:
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if (g_zero_clear && (bp->bio_flags & BIO_UNMAPPED) == 0)
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memset(bp->bio_data, g_zero_byte, bp->bio_length);
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/* FALLTHROUGH */
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case BIO_DELETE:
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case BIO_WRITE:
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bp->bio_completed = bp->bio_length;
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error = 0;
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break;
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case BIO_GETATTR:
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default:
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error = EOPNOTSUPP;
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break;
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}
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g_io_deliver(bp, error);
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}
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static void
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g_zero_init(struct g_class *mp)
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{
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struct g_geom *gp;
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struct g_provider *pp;
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g_topology_assert();
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gp = g_new_geomf(mp, "gzero");
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gp->start = g_zero_start;
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gp->access = g_std_access;
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gpp = pp = g_new_providerf(gp, "%s", gp->name);
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pp->flags |= G_PF_DIRECT_SEND | G_PF_DIRECT_RECEIVE;
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if (!g_zero_clear)
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pp->flags |= G_PF_ACCEPT_UNMAPPED;
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pp->mediasize = 1152921504606846976LLU;
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pp->sectorsize = 512;
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g_error_provider(pp, 0);
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}
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static int
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g_zero_destroy_geom(struct gctl_req *req __unused, struct g_class *mp __unused,
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struct g_geom *gp)
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{
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struct g_provider *pp;
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g_topology_assert();
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if (gp == NULL)
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return (0);
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pp = LIST_FIRST(&gp->provider);
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if (pp == NULL)
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return (0);
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if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0)
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return (EBUSY);
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gpp = NULL;
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g_wither_geom(gp, ENXIO);
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return (0);
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}
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static struct g_class g_zero_class = {
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.name = G_ZERO_CLASS_NAME,
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.version = G_VERSION,
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.init = g_zero_init,
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.destroy_geom = g_zero_destroy_geom
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};
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DECLARE_GEOM_CLASS(g_zero_class, g_zero);
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MODULE_VERSION(geom_zero, 0);
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