1 /*-
2 * Copyright (c) 1992, 1993, 1995
3 * The Regents of the University of California. All rights reserved.
4 * Copyright (c) 2000
5 * Poul-Henning Kamp. All rights reserved.
6 *
7 * This code is derived from software donated to Berkeley by
8 * Jan-Simon Pendry.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * @(#)kernfs_vfsops.c 8.10 (Berkeley) 5/14/95
32 * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36
33 *
34 * $FreeBSD: releng/8.0/sys/fs/devfs/devfs_vfsops.c 193511 2009-06-05 14:55:22Z rwatson $
35 */
36
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/kernel.h>
40 #include <sys/lock.h>
41 #include <sys/malloc.h>
42 #include <sys/mount.h>
43 #include <sys/proc.h>
44 #include <sys/sx.h>
45 #include <sys/vnode.h>
46 #include <sys/limits.h>
47
48 #include <fs/devfs/devfs.h>
49
50 static struct unrhdr *devfs_unr;
51
52 MALLOC_DEFINE(M_DEVFS, "DEVFS", "DEVFS data");
53
54 static vfs_mount_t devfs_mount;
55 static vfs_unmount_t devfs_unmount;
56 static vfs_root_t devfs_root;
57 static vfs_statfs_t devfs_statfs;
58
59 /*
60 * Mount the filesystem
61 */
62 static int
63 devfs_mount(struct mount *mp)
64 {
65 int error;
66 struct devfs_mount *fmp;
67 struct vnode *rvp;
68
69 if (devfs_unr == NULL)
70 devfs_unr = new_unrhdr(0, INT_MAX, NULL);
71
72 error = 0;
73
74 if (mp->mnt_flag & (MNT_UPDATE | MNT_ROOTFS))
75 return (EOPNOTSUPP);
76
77 fmp = malloc(sizeof *fmp, M_DEVFS, M_WAITOK | M_ZERO);
78 fmp->dm_idx = alloc_unr(devfs_unr);
79 sx_init(&fmp->dm_lock, "devfsmount");
80 fmp->dm_holdcnt = 1;
81
82 MNT_ILOCK(mp);
83 mp->mnt_flag |= MNT_LOCAL;
84 mp->mnt_kern_flag |= MNTK_MPSAFE;
85 #ifdef MAC
86 mp->mnt_flag |= MNT_MULTILABEL;
87 #endif
88 MNT_IUNLOCK(mp);
89 fmp->dm_mount = mp;
90 mp->mnt_data = (void *) fmp;
91 vfs_getnewfsid(mp);
92
93 fmp->dm_rootdir = devfs_vmkdir(fmp, NULL, 0, NULL, DEVFS_ROOTINO);
94
95 error = devfs_root(mp, LK_EXCLUSIVE, &rvp);
96 if (error) {
97 sx_destroy(&fmp->dm_lock);
98 free_unr(devfs_unr, fmp->dm_idx);
99 free(fmp, M_DEVFS);
100 return (error);
101 }
102
103 VOP_UNLOCK(rvp, 0);
104
105 vfs_mountedfrom(mp, "devfs");
106
107 return (0);
108 }
109
110 void
111 devfs_unmount_final(struct devfs_mount *fmp)
112 {
113 sx_destroy(&fmp->dm_lock);
114 free(fmp, M_DEVFS);
115 }
116
117 static int
118 devfs_unmount(struct mount *mp, int mntflags)
119 {
120 int error;
121 int flags = 0;
122 struct devfs_mount *fmp;
123 int hold;
124 u_int idx;
125
126 fmp = VFSTODEVFS(mp);
127 KASSERT(fmp->dm_mount != NULL,
128 ("devfs_unmount unmounted devfs_mount"));
129 /* There is 1 extra root vnode reference from devfs_mount(). */
130 error = vflush(mp, 1, flags, curthread);
131 if (error)
132 return (error);
133 sx_xlock(&fmp->dm_lock);
134 devfs_cleanup(fmp);
135 devfs_rules_cleanup(fmp);
136 fmp->dm_mount = NULL;
137 hold = --fmp->dm_holdcnt;
138 mp->mnt_data = NULL;
139 idx = fmp->dm_idx;
140 sx_xunlock(&fmp->dm_lock);
141 free_unr(devfs_unr, idx);
142 if (hold == 0)
143 devfs_unmount_final(fmp);
144 return 0;
145 }
146
147 /* Return locked reference to root. */
148
149 static int
150 devfs_root(struct mount *mp, int flags, struct vnode **vpp)
151 {
152 int error;
153 struct vnode *vp;
154 struct devfs_mount *dmp;
155
156 dmp = VFSTODEVFS(mp);
157 sx_xlock(&dmp->dm_lock);
158 error = devfs_allocv(dmp->dm_rootdir, mp, &vp);
159 if (error)
160 return (error);
161 vp->v_vflag |= VV_ROOT;
162 *vpp = vp;
163 return (0);
164 }
165
166 static int
167 devfs_statfs(struct mount *mp, struct statfs *sbp)
168 {
169
170 sbp->f_flags = 0;
171 sbp->f_bsize = DEV_BSIZE;
172 sbp->f_iosize = DEV_BSIZE;
173 sbp->f_blocks = 2; /* 1K to keep df happy */
174 sbp->f_bfree = 0;
175 sbp->f_bavail = 0;
176 sbp->f_files = 0;
177 sbp->f_ffree = 0;
178 return (0);
179 }
180
181 static struct vfsops devfs_vfsops = {
182 .vfs_mount = devfs_mount,
183 .vfs_root = devfs_root,
184 .vfs_statfs = devfs_statfs,
185 .vfs_unmount = devfs_unmount,
186 };
187
188 VFS_SET(devfs_vfsops, devfs, VFCF_SYNTHETIC);
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