vfs_init.c revision 140165
1/*- 2 * Copyright (c) 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed 6 * to Berkeley by John Heidemann of the UCLA Ficus project. 7 * 8 * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project 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. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 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_init.c 8.3 (Berkeley) 1/4/94 35 */ 36 37#include <sys/cdefs.h> 38__FBSDID("$FreeBSD: head/sys/kern/vfs_init.c 140165 2005-01-13 07:53:01Z phk $"); 39 40#include <sys/param.h> 41#include <sys/systm.h> 42#include <sys/kernel.h> 43#include <sys/linker.h> 44#include <sys/mount.h> 45#include <sys/proc.h> 46#include <sys/sysctl.h> 47#include <sys/vnode.h> 48#include <sys/malloc.h> 49 50 51MALLOC_DEFINE(M_VNODE, "vnodes", "Dynamically allocated vnodes"); 52 53/* 54 * The highest defined VFS number. 55 */ 56int maxvfsconf = VFS_GENERIC + 1; 57 58/* 59 * Single-linked list of configured VFSes. 60 * New entries are added/deleted by vfs_register()/vfs_unregister() 61 */ 62struct vfsconfhead vfsconf = TAILQ_HEAD_INITIALIZER(vfsconf); 63 64/* 65 * A Zen vnode attribute structure. 66 * 67 * Initialized when the first filesystem registers by vfs_register(). 68 */ 69struct vattr va_null; 70 71/* 72 * vfs_init.c 73 * 74 * Allocate and fill in operations vectors. 75 * 76 * An undocumented feature of this approach to defining operations is that 77 * there can be multiple entries in vfs_opv_descs for the same operations 78 * vector. This allows third parties to extend the set of operations 79 * supported by another layer in a binary compatibile way. For example, 80 * assume that NFS needed to be modified to support Ficus. NFS has an entry 81 * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by 82 * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions) 83 * listing those new operations Ficus adds to NFS, all without modifying the 84 * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but 85 * that is a(whole)nother story.) This is a feature. 86 */ 87 88/* 89 * Routines having to do with the management of the vnode table. 90 */ 91 92struct vfsconf * 93vfs_byname(const char *name) 94{ 95 struct vfsconf *vfsp; 96 97 if (!strcmp(name, "ffs")) 98 name = "ufs"; 99 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) 100 if (!strcmp(name, vfsp->vfc_name)) 101 return (vfsp); 102 return (NULL); 103} 104 105struct vfsconf * 106vfs_byname_kld(const char *fstype, struct thread *td, int *error) 107{ 108 struct vfsconf *vfsp; 109 linker_file_t lf; 110 111 vfsp = vfs_byname(fstype); 112 if (vfsp != NULL) 113 return (vfsp); 114 115 /* Only load modules for root (very important!). */ 116 *error = suser(td); 117 if (*error) 118 return (NULL); 119 *error = securelevel_gt(td->td_ucred, 0); 120 if (*error) 121 return (NULL); 122 *error = linker_load_module(NULL, fstype, NULL, NULL, &lf); 123 if (lf == NULL) 124 *error = ENODEV; 125 if (*error) 126 return (NULL); 127 lf->userrefs++; 128 /* Look up again to see if the VFS was loaded. */ 129 vfsp = vfs_byname(fstype); 130 if (vfsp == NULL) { 131 lf->userrefs--; 132 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 133 *error = ENODEV; 134 return (NULL); 135 } 136 return (vfsp); 137} 138 139 140/* Register a new filesystem type in the global table */ 141int 142vfs_register(struct vfsconf *vfc) 143{ 144 struct sysctl_oid *oidp; 145 struct vfsops *vfsops; 146 static int once; 147 148 if (!once) { 149 vattr_null(&va_null); 150 once = 1; 151 } 152 153 if (vfc->vfc_version != VFS_VERSION) { 154 printf("ERROR: filesystem %s, unsupported ABI version %x\n", 155 vfc->vfc_name, vfc->vfc_version); 156 return (EINVAL); 157 } 158 if (vfs_byname(vfc->vfc_name) != NULL) 159 return EEXIST; 160 161 vfc->vfc_typenum = maxvfsconf++; 162 TAILQ_INSERT_TAIL(&vfsconf, vfc, vfc_list); 163 164 /* 165 * If this filesystem has a sysctl node under vfs 166 * (i.e. vfs.xxfs), then change the oid number of that node to 167 * match the filesystem's type number. This allows user code 168 * which uses the type number to read sysctl variables defined 169 * by the filesystem to continue working. Since the oids are 170 * in a sorted list, we need to make sure the order is 171 * preserved by re-registering the oid after modifying its 172 * number. 173 */ 174 SLIST_FOREACH(oidp, &sysctl__vfs_children, oid_link) 175 if (strcmp(oidp->oid_name, vfc->vfc_name) == 0) { 176 sysctl_unregister_oid(oidp); 177 oidp->oid_number = vfc->vfc_typenum; 178 sysctl_register_oid(oidp); 179 } 180 181 /* 182 * Initialise unused ``struct vfsops'' fields, to use 183 * the vfs_std*() functions. Note, we need the mount 184 * and unmount operations, at the least. The check 185 * for vfsops available is just a debugging aid. 186 */ 187 KASSERT(vfc->vfc_vfsops != NULL, 188 ("Filesystem %s has no vfsops", vfc->vfc_name)); 189 /* 190 * Check the mount and unmount operations. 191 */ 192 vfsops = vfc->vfc_vfsops; 193 KASSERT(vfsops->vfs_mount != NULL, 194 ("Filesystem %s has no mount op", vfc->vfc_name)); 195 KASSERT(vfsops->vfs_unmount != NULL, 196 ("Filesystem %s has no unmount op", vfc->vfc_name)); 197 198 if (vfsops->vfs_start == NULL) 199 /* make a file system operational */ 200 vfsops->vfs_start = vfs_stdstart; 201 if (vfsops->vfs_root == NULL) 202 /* return file system's root vnode */ 203 vfsops->vfs_root = vfs_stdroot; 204 if (vfsops->vfs_quotactl == NULL) 205 /* quota control */ 206 vfsops->vfs_quotactl = vfs_stdquotactl; 207 if (vfsops->vfs_statfs == NULL) 208 /* return file system's status */ 209 vfsops->vfs_statfs = vfs_stdstatfs; 210 if (vfsops->vfs_sync == NULL) 211 /* 212 * flush unwritten data (nosync) 213 * file systems can use vfs_stdsync 214 * explicitly by setting it in the 215 * vfsop vector. 216 */ 217 vfsops->vfs_sync = vfs_stdnosync; 218 if (vfsops->vfs_vget == NULL) 219 /* convert an inode number to a vnode */ 220 vfsops->vfs_vget = vfs_stdvget; 221 if (vfsops->vfs_fhtovp == NULL) 222 /* turn an NFS file handle into a vnode */ 223 vfsops->vfs_fhtovp = vfs_stdfhtovp; 224 if (vfsops->vfs_checkexp == NULL) 225 /* check if file system is exported */ 226 vfsops->vfs_checkexp = vfs_stdcheckexp; 227 if (vfsops->vfs_vptofh == NULL) 228 /* turn a vnode into an NFS file handle */ 229 vfsops->vfs_vptofh = vfs_stdvptofh; 230 if (vfsops->vfs_init == NULL) 231 /* file system specific initialisation */ 232 vfsops->vfs_init = vfs_stdinit; 233 if (vfsops->vfs_uninit == NULL) 234 /* file system specific uninitialisation */ 235 vfsops->vfs_uninit = vfs_stduninit; 236 if (vfsops->vfs_extattrctl == NULL) 237 /* extended attribute control */ 238 vfsops->vfs_extattrctl = vfs_stdextattrctl; 239 if (vfsops->vfs_sysctl == NULL) 240 vfsops->vfs_sysctl = vfs_stdsysctl; 241 242 /* 243 * Call init function for this VFS... 244 */ 245 (*(vfc->vfc_vfsops->vfs_init))(vfc); 246 247 return 0; 248} 249 250 251/* Remove registration of a filesystem type */ 252int 253vfs_unregister(struct vfsconf *vfc) 254{ 255 struct vfsconf *vfsp; 256 int error, i, maxtypenum; 257 258 i = vfc->vfc_typenum; 259 260 vfsp = vfs_byname(vfc->vfc_name); 261 if (vfsp == NULL) 262 return EINVAL; 263 if (vfsp->vfc_refcount) 264 return EBUSY; 265 if (vfc->vfc_vfsops->vfs_uninit != NULL) { 266 error = (*vfc->vfc_vfsops->vfs_uninit)(vfsp); 267 if (error) 268 return (error); 269 } 270 TAILQ_REMOVE(&vfsconf, vfsp, vfc_list); 271 maxtypenum = VFS_GENERIC; 272 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) 273 if (maxtypenum < vfsp->vfc_typenum) 274 maxtypenum = vfsp->vfc_typenum; 275 maxvfsconf = maxtypenum + 1; 276 return 0; 277} 278 279/* 280 * Standard kernel module handling code for filesystem modules. 281 * Referenced from VFS_SET(). 282 */ 283int 284vfs_modevent(module_t mod, int type, void *data) 285{ 286 struct vfsconf *vfc; 287 int error = 0; 288 289 vfc = (struct vfsconf *)data; 290 291 switch (type) { 292 case MOD_LOAD: 293 if (vfc) 294 error = vfs_register(vfc); 295 break; 296 297 case MOD_UNLOAD: 298 if (vfc) 299 error = vfs_unregister(vfc); 300 break; 301 default: 302 error = EOPNOTSUPP; 303 break; 304 } 305 return (error); 306} 307