vfs_mount.c revision 51388 
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 * $FreeBSD: head/sys/kern/vfs_mount.c 51388 1999-09-19 06:24:21Z dillon $
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
68MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount struct");
69
70/*
71 *  These define the root filesystem, device, and root filesystem type.
72 */
73dev_t rootdevs[] = { NODEV, NODEV };
74char *rootdevnames[2];
75struct vnode *rootvnode;
76char *mountrootfsname;
77#ifdef BOOTP
78extern void bootpc_init __P((void));
79#endif
80
81/*
82 * vfs_init() will set maxvfsconf
83 * to the highest defined type number.
84 */
85int maxvfsconf;
86struct 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 */
115static void
116vfs_mountrootfs(void *unused)
117{
118	struct mount		*mp;
119	int			err;
120	struct proc		*p = curproc;	/* XXX */
121	int			s;
122	int			i;
123	dev_t			orootdev;
124
125#ifdef BOOTP
126	bootpc_init();
127#endif
128	/*
129	 *  New root mount structure
130	 */
131	if ((err = vfs_rootmountalloc(mountrootfsname, ROOTNAME, &mp))) {
132		printf("rootdev=%p error=%d,  ", (void *)rootdev, err);
133		panic("cannot mount root\n");
134		return ;
135	}
136	mp->mnt_flag		|= MNT_ROOTFS;
137
138	/*
139	 * If we have no idea what the device is because the VFS root mount
140	 * initialization code couldn't figure it out, take a guess by
141	 * assuming that vfs_getnewfsid() will be called when we try the
142	 * mount.  For the moment this is necessary for NFS-baesd BOOTP
143	 * boots.  Ultimately we would like to get rid of 'rootdev' entirely
144	 * and go with a linked list of possible roots and device-specific
145	 * auxillary data that we do not try to interpret ourselves.
146	 */
147	if (rootdev == NODEV && rootdevs[0] == NODEV)
148		rootdev = vfs_getrootfsid(mp);
149
150	/*
151	 * Attempt the mount.  This is rather messy due to many historical
152	 * layers.  Basically what it comes down to is that 'rootdev' is an
153	 * override to the rootdevs[] array.  The rootdevs[] array itself
154	 * cannot normally be accessed directly by other modules, but FFS
155	 * plays with it.  NFS, on the otherhand, has no clue what the
156	 * device assignment for a mount will be until it actually does it.
157	 *
158	 * During the loop we set rootdev to rootdevs[i].  This is used
159	 * by FFS and a few other modules.  It is ignored by NFS.
160	 */
161	err = ENXIO;
162	orootdev = rootdev;
163	if (rootdevs[0] == NODEV)
164		rootdevs[0] = rootdev;
165	for (i = 0; i < sizeof(rootdevs) / sizeof(rootdevs[0]); i++) {
166		if (rootdevs[i] == NODEV)
167			break;
168		rootdev = rootdevs[i];
169		if (rootdev != orootdev) {
170			s = splbio();	/* Overkill, but harmless.. */
171			printf("changing root device to %s\n", rootdevnames[i]);
172			splx(s);
173			orootdev = rootdev;
174		}
175		strncpy(mp->mnt_stat.f_mntfromname,
176		    rootdevnames[i] ? rootdevnames[i] : ROOTNAME, MNAMELEN - 1);
177		err = VFS_MOUNT(mp, NULL, NULL, NULL, p);
178		if (err != ENXIO)
179			break;
180	}
181	if (err) {
182		/*
183		 * XXX should ask the user for the name in some cases.
184		 * Why do we call vfs_unbusy() here and not after ENXIO
185		 * is returned above?
186		 */
187		vfs_unbusy(mp, p);
188		/*
189		 * free mount struct before failing
190		 * (hardly worthwhile with the PANIC eh?)
191		 */
192		free( mp, M_MOUNT);
193		printf("rootdev=%p error=%d,  ", (void *)rootdev, err);
194		panic("cannot mount root (2)\n");
195		return;
196	}
197
198	simple_lock(&mountlist_slock);
199
200	/*
201	 * Add fs to list of mounted file systems
202	 */
203	CIRCLEQ_INSERT_HEAD(&mountlist, mp, mnt_list);
204
205	simple_unlock(&mountlist_slock);
206	vfs_unbusy(mp, p);
207
208	/* root mount, update system time from FS specific data*/
209	inittodr(mp->mnt_time);
210	return;
211}
212
213SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_FIRST, vfs_mountrootfs, NULL)
214
215