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      1 /*
      2  * CDDL HEADER START
      3  *
      4  * The contents of this file are subject to the terms of the
      5  * Common Development and Distribution License (the "License").
      6  * You may not use this file except in compliance with the License.
      7  *
      8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      9  * or http://www.opensolaris.org/os/licensing.
     10  * See the License for the specific language governing permissions
     11  * and limitations under the License.
     12  *
     13  * When distributing Covered Code, include this CDDL HEADER in each
     14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     15  * If applicable, add the following below this CDDL HEADER, with the
     16  * fields enclosed by brackets "[]" replaced with your own identifying
     17  * information: Portions Copyright [yyyy] [name of copyright owner]
     18  *
     19  * CDDL HEADER END
     20  */
     21 /*
     22  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
     23  * Use is subject to license terms.
     24  */
     25 
     26 #pragma ident	"@(#)vdev_missing.c	1.3	07/11/27 SMI"
     27 
     28 /*
     29  * The 'missing' vdev is a special vdev type used only during import.  It
     30  * signifies a placeholder in the root vdev for some vdev that we know is
     31  * missing.  We pass it down to the kernel to allow the rest of the
     32  * configuration to parsed and an attempt made to open all available devices.
     33  * Because its GUID is always 0, we know that the guid sum will mismatch and we
     34  * won't be able to open the pool anyway.
     35  */
     36 
     37 #include <sys/zfs_context.h>
     38 #include <sys/spa.h>
     39 #include <sys/vdev_impl.h>
     40 #include <sys/fs/zfs.h>
     41 #include <sys/zio.h>
     42 
     43 /* ARGSUSED */
     44 static int
     45 vdev_missing_open(vdev_t *vd, uint64_t *psize, uint64_t *ashift)
     46 {
     47 	/*
     48 	 * Really this should just fail.  But then the root vdev will be in the
     49 	 * faulted state with VDEV_AUX_NO_REPLICAS, when what we really want is
     50 	 * VDEV_AUX_BAD_GUID_SUM.  So we pretend to succeed, knowing that we
     51 	 * will fail the GUID sum check before ever trying to open the pool.
     52 	 */
     53 	*psize = SPA_MINDEVSIZE;
     54 	*ashift = SPA_MINBLOCKSHIFT;
     55 	return (0);
     56 }
     57 
     58 /* ARGSUSED */
     59 static void
     60 vdev_missing_close(vdev_t *vd)
     61 {
     62 }
     63 
     64 /* ARGSUSED */
     65 static int
     66 vdev_missing_io_start(zio_t *zio)
     67 {
     68 	zio->io_error = ENOTSUP;
     69 	return (ZIO_PIPELINE_CONTINUE);
     70 }
     71 
     72 /* ARGSUSED */
     73 static int
     74 vdev_missing_io_done(zio_t *zio)
     75 {
     76 	return (ZIO_PIPELINE_CONTINUE);
     77 }
     78 
     79 /* ARGSUSED */
     80 static int
     81 vdev_missing_probe(vdev_t *vd)
     82 {
     83 	return (0);
     84 }
     85 
     86 vdev_ops_t vdev_missing_ops = {
     87 	vdev_missing_open,
     88 	vdev_missing_close,
     89 	vdev_missing_probe,
     90 	vdev_default_asize,
     91 	vdev_missing_io_start,
     92 	vdev_missing_io_done,
     93 	NULL,
     94 	VDEV_TYPE_MISSING,	/* name of this vdev type */
     95 	B_TRUE			/* leaf vdev */
     96 };
     97