xref: /freebsd/sys/kern/vfs_mount.c (revision a8445737e740901f5f2c8d24c12ef7fc8b00134e)
1 /*
2  * Copyright (c) 1989, 1993, 1995
3  *	The Regents of the University of California.  All rights reserved.
4  * Copyright (c) 1995 Artisoft, Inc.  All Rights Reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. All advertising materials mentioning features or use of this software
15  *    must display the following acknowledgement:
16  *	This product includes software developed by the University of
17  *	California, Berkeley and its contributors.
18  * 4. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)vfs_conf.c	8.8 (Berkeley) 3/31/94
35  * $Id: vfs_conf.c,v 1.25 1998/06/09 12:52:33 bde Exp $
36  */
37 
38 /*
39  * PURPOSE:	This file abstracts the root mounting interface from
40  *		the per file system semantics for handling mounts,
41  *		the overall intent of which is to move the BSD
42  *		internals dependence out of the FS code, both to
43  *		make the FS code more portable and to free up some
44  *		of the BSD internals so that they may more easily
45  *		be changed.
46  *
47  * NOTE1:	Code is single entry/single exit to aid debugging
48  *		and conversion for kernel multithreading.
49  *
50  * NOTE2:	Code notes lock state in headers on entry and exit
51  *		as an aid to conversion for kernel multithreading
52  *		on SMP reentrancy
53  */
54 #include "opt_bootp.h"
55 
56 #include <sys/param.h>		/* dev_t (types.h)*/
57 #include <sys/kernel.h>
58 #include <sys/systm.h>		/* rootvp*/
59 #include <sys/proc.h>		/* curproc*/
60 #include <sys/vnode.h>		/* NULLVP*/
61 #include <sys/mount.h>		/* struct mount*/
62 #include <sys/malloc.h>		/* M_MOUNT*/
63 
64 /*
65  * GLOBALS
66  */
67 
68 MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount struct");
69 
70 /*
71  *  These define the root filesystem, device, and root filesystem type.
72  */
73 dev_t rootdevs[] = { NODEV, NODEV };
74 char *rootdevnames[2];
75 struct vnode *rootvnode;
76 char *mountrootfsname;
77 #ifdef BOOTP
78 extern void bootpc_init __P((void));
79 #endif
80 
81 /*
82  * vfs_init() will set maxvfsconf
83  * to the highest defined type number.
84  */
85 int maxvfsconf;
86 struct vfsconf *vfsconf;
87 
88 /*
89  * Common root mount code shared by all filesystems
90  */
91 #define ROOTNAME	"root_device"
92 
93 /*
94  * vfs_mountrootfs
95  *
96  * Common entry point for root mounts
97  *
98  * PARAMETERS:
99  * 		NONE
100  *
101  * RETURNS:	0	Success
102  *		!0	error number (errno.h)
103  *
104  * LOCK STATE:
105  *		ENTRY
106  *			<no locks held>
107  *		EXIT
108  *			<no locks held>
109  *
110  * NOTES:
111  *		This code is currently supported only for use for
112  *		the FFS file system type.  This is a matter of
113  *		fixing the other file systems, not this code!
114  */
115 static void
116 vfs_mountrootfs(void *unused)
117 {
118 	struct mount		*mp;
119 	int			i, err;
120 	struct proc		*p = curproc;	/* XXX */
121 	dev_t			orootdev;
122 
123 #ifdef BOOTP
124 	bootpc_init();
125 #endif
126 	/*
127 	 *  New root mount structure
128 	 */
129 	if ((err = vfs_rootmountalloc(mountrootfsname, ROOTNAME, &mp))) {
130 		printf("error %d: ", err);
131 		panic("cannot mount root\n");
132 		return ;
133 	}
134 	mp->mnt_flag		|= MNT_ROOTFS;
135 
136 	/*
137 	 * Attempt the mount
138 	 */
139 	err = ENXIO;
140 	orootdev = rootdev;
141 	if (rootdevs[0] == NODEV)
142 		rootdevs[0] = rootdev;
143 	for (i = 0; i < sizeof(rootdevs) / sizeof(rootdevs[0]); i++) {
144 		if (rootdevs[i] == NODEV)
145 			break;
146 		rootdev = rootdevs[i];
147 		if (rootdev != orootdev) {
148 			printf("changing root device to %s\n", rootdevnames[i]);
149 			orootdev = rootdev;
150 		}
151 		strncpy(mp->mnt_stat.f_mntfromname,
152 		    rootdevnames[i] ? rootdevnames[i] : ROOTNAME, MNAMELEN - 1);
153 		err = VFS_MOUNT(mp, NULL, NULL, NULL, p);
154 		if (err != ENXIO)
155 			break;
156 	}
157 	if (err) {
158 		/*
159 		 * XXX should ask the user for the name in some cases.
160 		 * Why do we call vfs_unbusy() here and not after ENXIO
161 		 * is returned above?
162 		 */
163 		vfs_unbusy(mp, p);
164 		/*
165 		 * free mount struct before failing
166 		 * (hardly worthwhile with the PANIC eh?)
167 		 */
168 		free( mp, M_MOUNT);
169 		printf("error %d: ", err);
170 		panic("cannot mount root (2)\n");
171 		return;
172 	}
173 
174 	simple_lock(&mountlist_slock);
175 
176 	/*
177 	 * Add fs to list of mounted file systems
178 	 */
179 	CIRCLEQ_INSERT_HEAD(&mountlist, mp, mnt_list);
180 
181 	simple_unlock(&mountlist_slock);
182 	vfs_unbusy(mp, p);
183 
184 	/* root mount, update system time from FS specific data*/
185 	inittodr(mp->mnt_time);
186 	return;
187 }
188 
189 SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_FIRST, vfs_mountrootfs, NULL)
190 
191