projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 3c4390e8 KM |
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 | * | |
| 17 | * @(#)vfs_subr.c 7.1 (Berkeley) %G% | |
| 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" | |
| 28 | #include "errno.h" | |
| 29 | ||
| 30 | /* | |
| 31 | * Add a new mount point to the list of mounted filesystems. | |
| 32 | * Lock the filesystem so that namei will not cross into the | |
| 33 | * the tree below the covered vnode. | |
| 34 | */ | |
| 35 | vfs_add(mountedvp, mp, flags) | |
| 36 | register struct vnode *mountedvp; | |
| 37 | register struct mount *mp; | |
| 38 | int flags; | |
| 39 | { | |
| 40 | register int error; | |
| 41 | ||
| 42 | error = vfs_lock(mp); | |
| 43 | if (error) | |
| 44 | return (error); | |
| 45 | if (mountedvp == (struct vnode *)0) { | |
| 46 | /* | |
| 47 | * We are mounting the root filesystem. | |
| 48 | */ | |
| 49 | rootfs = mp; | |
| 50 | mp->m_next = mp; | |
| 51 | mp->m_prev = mp; | |
| 52 | } else { | |
| 53 | if (mountedvp->v_mountedhere != (struct mount *)0) { | |
| 54 | vfs_unlock(mp); | |
| 55 | return(EBUSY); | |
| 56 | } | |
| 57 | /* | |
| 58 | * Put the new filesystem on the mount list after root. | |
| 59 | */ | |
| 60 | mp->m_next = rootfs->m_next; | |
| 61 | mp->m_prev = rootfs; | |
| 62 | rootfs->m_next = mp; | |
| 63 | mp->m_next->m_prev = mp; | |
| 64 | mountedvp->v_mountedhere = mp; | |
| 65 | } | |
| 66 | mp->m_vnodecovered = mountedvp; | |
| 67 | if (flags & M_RDONLY) { | |
| 68 | mp->m_flag |= M_RDONLY; | |
| 69 | } else { | |
| 70 | mp->m_flag &= ~M_RDONLY; | |
| 71 | } | |
| 72 | if (flags & M_NOSUID) { | |
| 73 | mp->m_flag |= M_NOSUID; | |
| 74 | } else { | |
| 75 | mp->m_flag &= ~M_NOSUID; | |
| 76 | } | |
| 77 | return (0); | |
| 78 | } | |
| 79 | ||
| 80 | /* | |
| 81 | * Remove a mount point from the list of mounted filesystems. | |
| 82 | * Unmount of the root is illegal. | |
| 83 | */ | |
| 84 | void | |
| 85 | vfs_remove(mp) | |
| 86 | register struct mount *mp; | |
| 87 | { | |
| 88 | ||
| 89 | if (mp == rootfs) | |
| 90 | panic("vfs_remove: unmounting root"); | |
| 91 | mp->m_prev->m_next = mp->m_next; | |
| 92 | mp->m_next->m_prev = mp->m_prev; | |
| 93 | mp->m_vnodecovered->v_mountedhere = (struct mount *)0; | |
| 94 | vfs_unlock(mp); | |
| 95 | } | |
| 96 | ||
| 97 | /* | |
| 98 | * Lock a filesystem. | |
| 99 | * Used to prevent access to it while mounting and unmounting. | |
| 100 | */ | |
| 101 | vfs_lock(mp) | |
| 102 | register struct mount *mp; | |
| 103 | { | |
| 104 | ||
| 105 | if (mp->m_flag & M_MLOCK) | |
| 106 | return (EBUSY); | |
| 107 | mp->m_flag |= M_MLOCK; | |
| 108 | return (0); | |
| 109 | } | |
| 110 | ||
| 111 | /* | |
| 112 | * Unlock a locked filesystem. | |
| 113 | * Panic if filesystem is not locked. | |
| 114 | */ | |
| 115 | void | |
| 116 | vfs_unlock(mp) | |
| 117 | register struct mount *mp; | |
| 118 | { | |
| 119 | ||
| 120 | if ((mp->m_flag & M_MLOCK) == 0) | |
| 121 | panic("vfs_unlock: locked fs"); | |
| 122 | mp->m_flag &= ~M_MLOCK; | |
| 123 | if (mp->m_flag & M_MWAIT) { | |
| 124 | mp->m_flag &= ~M_MWAIT; | |
| 125 | wakeup((caddr_t)mp); | |
| 126 | } | |
| 127 | } | |
| 128 | ||
| 129 | /* | |
| 130 | * Lookup a mount point by filesystem identifier. | |
| 131 | */ | |
| 132 | struct mount * | |
| 133 | getvfs(fsid) | |
| 134 | fsid_t *fsid; | |
| 135 | { | |
| 136 | register struct mount *mp; | |
| 137 | ||
| 138 | for (mp = rootfs; mp; mp = mp->m_next) { | |
| 139 | if (mp->m_fsid.val[0] == fsid->val[0] && | |
| 140 | mp->m_fsid.val[1] == fsid->val[1]) { | |
| 141 | break; | |
| 142 | } | |
| 143 | } | |
| 144 | return (mp); | |
| 145 | } | |
| 146 | ||
| 147 | /* | |
| 148 | * Set vnode attributes to VNOVAL | |
| 149 | */ | |
| 150 | void vattr_null(vap) | |
| 151 | register struct vattr *vap; | |
| 152 | { | |
| 153 | ||
| 154 | vap->va_type = VNON; | |
| 155 | vap->va_mode = vap->va_nlink = vap->va_uid = vap->va_gid = | |
| 156 | vap->va_fsid = vap->va_fileid = vap->va_size = | |
| 157 | vap->va_size1 = vap->va_blocksize = vap->va_rdev = | |
| 158 | vap->va_bytes = vap->va_bytes1 = | |
| 159 | vap->va_atime.tv_sec = vap->va_atime.tv_usec = | |
| 160 | vap->va_mtime.tv_sec = vap->va_mtime.tv_usec = | |
| 161 | vap->va_ctime.tv_sec = vap->va_ctime.tv_usec = VNOVAL; | |
| 162 | } |