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1 | /* |
2 | * Copyright (c) 1989 The Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms are permitted | |
6 | * provided that the above copyright notice and this paragraph are | |
7 | * duplicated in all such forms and that any documentation, | |
8 | * advertising materials, and other materials related to such | |
9 | * distribution and use acknowledge that the software was developed | |
10 | * by the University of California, Berkeley. The name of the | |
11 | * University may not be used to endorse or promote products derived | |
12 | * from this software without specific prior written permission. | |
13 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR | |
14 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED | |
15 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. | |
16 | * | |
8fe1c702 | 17 | * @(#)vfs_subr.c 7.5 (Berkeley) %G% |
3c4390e8 KM |
18 | */ |
19 | ||
20 | /* | |
21 | * External virtual filesystem routines | |
22 | */ | |
23 | ||
24 | #include "param.h" | |
25 | #include "mount.h" | |
26 | #include "time.h" | |
27 | #include "vnode.h" | |
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28 | #include "namei.h" |
29 | #include "ucred.h" | |
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30 | #include "errno.h" |
31 | ||
32 | /* | |
33 | * Add a new mount point to the list of mounted filesystems. | |
34 | * Lock the filesystem so that namei will not cross into the | |
35 | * the tree below the covered vnode. | |
36 | */ | |
37 | vfs_add(mountedvp, mp, flags) | |
38 | register struct vnode *mountedvp; | |
39 | register struct mount *mp; | |
40 | int flags; | |
41 | { | |
42 | register int error; | |
43 | ||
44 | error = vfs_lock(mp); | |
45 | if (error) | |
46 | return (error); | |
47 | if (mountedvp == (struct vnode *)0) { | |
48 | /* | |
49 | * We are mounting the root filesystem. | |
50 | */ | |
51 | rootfs = mp; | |
52 | mp->m_next = mp; | |
53 | mp->m_prev = mp; | |
54 | } else { | |
55 | if (mountedvp->v_mountedhere != (struct mount *)0) { | |
56 | vfs_unlock(mp); | |
57 | return(EBUSY); | |
58 | } | |
59 | /* | |
60 | * Put the new filesystem on the mount list after root. | |
61 | */ | |
62 | mp->m_next = rootfs->m_next; | |
63 | mp->m_prev = rootfs; | |
64 | rootfs->m_next = mp; | |
65 | mp->m_next->m_prev = mp; | |
66 | mountedvp->v_mountedhere = mp; | |
67 | } | |
68 | mp->m_vnodecovered = mountedvp; | |
69 | if (flags & M_RDONLY) { | |
70 | mp->m_flag |= M_RDONLY; | |
71 | } else { | |
72 | mp->m_flag &= ~M_RDONLY; | |
73 | } | |
74 | if (flags & M_NOSUID) { | |
75 | mp->m_flag |= M_NOSUID; | |
76 | } else { | |
77 | mp->m_flag &= ~M_NOSUID; | |
78 | } | |
79 | return (0); | |
80 | } | |
81 | ||
82 | /* | |
83 | * Remove a mount point from the list of mounted filesystems. | |
84 | * Unmount of the root is illegal. | |
85 | */ | |
86 | void | |
87 | vfs_remove(mp) | |
88 | register struct mount *mp; | |
89 | { | |
90 | ||
91 | if (mp == rootfs) | |
92 | panic("vfs_remove: unmounting root"); | |
93 | mp->m_prev->m_next = mp->m_next; | |
94 | mp->m_next->m_prev = mp->m_prev; | |
95 | mp->m_vnodecovered->v_mountedhere = (struct mount *)0; | |
96 | vfs_unlock(mp); | |
97 | } | |
98 | ||
99 | /* | |
100 | * Lock a filesystem. | |
101 | * Used to prevent access to it while mounting and unmounting. | |
102 | */ | |
103 | vfs_lock(mp) | |
104 | register struct mount *mp; | |
105 | { | |
106 | ||
107 | if (mp->m_flag & M_MLOCK) | |
108 | return (EBUSY); | |
109 | mp->m_flag |= M_MLOCK; | |
110 | return (0); | |
111 | } | |
112 | ||
113 | /* | |
114 | * Unlock a locked filesystem. | |
115 | * Panic if filesystem is not locked. | |
116 | */ | |
117 | void | |
118 | vfs_unlock(mp) | |
119 | register struct mount *mp; | |
120 | { | |
121 | ||
122 | if ((mp->m_flag & M_MLOCK) == 0) | |
123 | panic("vfs_unlock: locked fs"); | |
124 | mp->m_flag &= ~M_MLOCK; | |
125 | if (mp->m_flag & M_MWAIT) { | |
126 | mp->m_flag &= ~M_MWAIT; | |
127 | wakeup((caddr_t)mp); | |
128 | } | |
129 | } | |
130 | ||
131 | /* | |
132 | * Lookup a mount point by filesystem identifier. | |
133 | */ | |
134 | struct mount * | |
135 | getvfs(fsid) | |
136 | fsid_t *fsid; | |
137 | { | |
138 | register struct mount *mp; | |
139 | ||
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140 | mp = rootfs; |
141 | do { | |
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142 | if (mp->m_fsid.val[0] == fsid->val[0] && |
143 | mp->m_fsid.val[1] == fsid->val[1]) { | |
d713f801 | 144 | return (mp); |
3c4390e8 | 145 | } |
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146 | mp = mp->m_next; |
147 | } while (mp != rootfs); | |
148 | return ((struct mount *)0); | |
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149 | } |
150 | ||
151 | /* | |
152 | * Set vnode attributes to VNOVAL | |
153 | */ | |
154 | void vattr_null(vap) | |
155 | register struct vattr *vap; | |
156 | { | |
157 | ||
158 | vap->va_type = VNON; | |
159 | vap->va_mode = vap->va_nlink = vap->va_uid = vap->va_gid = | |
160 | vap->va_fsid = vap->va_fileid = vap->va_size = | |
161 | vap->va_size1 = vap->va_blocksize = vap->va_rdev = | |
162 | vap->va_bytes = vap->va_bytes1 = | |
163 | vap->va_atime.tv_sec = vap->va_atime.tv_usec = | |
164 | vap->va_mtime.tv_sec = vap->va_mtime.tv_usec = | |
8cf4d4fb KM |
165 | vap->va_ctime.tv_sec = vap->va_ctime.tv_usec = |
166 | vap->va_flags = vap->va_gen = VNOVAL; | |
3c4390e8 | 167 | } |
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168 | |
169 | /* | |
170 | * Initialize a nameidata structure | |
171 | */ | |
172 | ndinit(ndp) | |
173 | register struct nameidata *ndp; | |
174 | { | |
175 | ||
176 | bzero((caddr_t)ndp, sizeof(struct nameidata)); | |
177 | ndp->ni_iov = &ndp->ni_nd.nd_iovec; | |
178 | ndp->ni_iovcnt = 1; | |
179 | ndp->ni_base = (caddr_t)&ndp->ni_dent; | |
180 | ndp->ni_rw = UIO_WRITE; | |
181 | ndp->ni_segflg = UIO_SYSSPACE; | |
182 | } | |
183 | ||
184 | /* | |
185 | * Duplicate a nameidata structure | |
186 | */ | |
187 | nddup(ndp, newndp) | |
188 | register struct nameidata *ndp, *newndp; | |
189 | { | |
190 | ||
191 | ndinit(newndp); | |
192 | newndp->ni_cdir = ndp->ni_cdir; | |
8fe1c702 | 193 | VREF(newndp->ni_cdir); |
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194 | newndp->ni_rdir = ndp->ni_rdir; |
195 | if (newndp->ni_rdir) | |
8fe1c702 | 196 | VREF(newndp->ni_rdir); |
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197 | newndp->ni_cred = ndp->ni_cred; |
198 | crhold(newndp->ni_cred); | |
199 | } | |
200 | ||
201 | /* | |
202 | * Release a nameidata structure | |
203 | */ | |
204 | ndrele(ndp) | |
205 | register struct nameidata *ndp; | |
206 | { | |
207 | ||
208 | vrele(ndp->ni_cdir); | |
209 | if (ndp->ni_rdir) | |
210 | vrele(ndp->ni_rdir); | |
211 | crfree(ndp->ni_cred); | |
212 | } |