1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed 8 * to Berkeley by John Heidemann of the UCLA Ficus project. 9 * 10 * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)vfs_init.c 8.3 (Berkeley) 1/4/94 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/fnv_hash.h> 45 #include <sys/kernel.h> 46 #include <sys/linker.h> 47 #include <sys/mount.h> 48 #include <sys/proc.h> 49 #include <sys/sx.h> 50 #include <sys/syscallsubr.h> 51 #include <sys/sysctl.h> 52 #include <sys/vnode.h> 53 #include <sys/malloc.h> 54 55 static int vfs_register(struct vfsconf *); 56 static int vfs_unregister(struct vfsconf *); 57 58 MALLOC_DEFINE(M_VNODE, "vnodes", "Dynamically allocated vnodes"); 59 60 /* 61 * The highest defined VFS number. 62 */ 63 int maxvfsconf = VFS_GENERIC + 1; 64 65 /* 66 * Single-linked list of configured VFSes. 67 * New entries are added/deleted by vfs_register()/vfs_unregister() 68 */ 69 struct vfsconfhead vfsconf = TAILQ_HEAD_INITIALIZER(vfsconf); 70 struct sx vfsconf_sx; 71 SX_SYSINIT(vfsconf, &vfsconf_sx, "vfsconf"); 72 73 /* 74 * Loader.conf variable vfs.typenumhash enables setting vfc_typenum using a hash 75 * calculation on vfc_name, so that it doesn't change when file systems are 76 * loaded in a different order. This will avoid the NFS server file handles from 77 * changing for file systems that use vfc_typenum in their fsid. 78 */ 79 static int vfs_typenumhash = 1; 80 SYSCTL_INT(_vfs, OID_AUTO, typenumhash, CTLFLAG_RDTUN, &vfs_typenumhash, 0, 81 "Set vfc_typenum using a hash calculation on vfc_name, so that it does not" 82 "change when file systems are loaded in a different order."); 83 84 /* 85 * A Zen vnode attribute structure. 86 * 87 * Initialized when the first filesystem registers by vfs_register(). 88 */ 89 struct vattr va_null; 90 91 /* 92 * vfs_init.c 93 * 94 * Allocate and fill in operations vectors. 95 * 96 * An undocumented feature of this approach to defining operations is that 97 * there can be multiple entries in vfs_opv_descs for the same operations 98 * vector. This allows third parties to extend the set of operations 99 * supported by another layer in a binary compatibile way. For example, 100 * assume that NFS needed to be modified to support Ficus. NFS has an entry 101 * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by 102 * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions) 103 * listing those new operations Ficus adds to NFS, all without modifying the 104 * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but 105 * that is a(whole)nother story.) This is a feature. 106 */ 107 108 /* 109 * Routines having to do with the management of the vnode table. 110 */ 111 112 static struct vfsconf * 113 vfs_byname_locked(const char *name) 114 { 115 struct vfsconf *vfsp; 116 117 sx_assert(&vfsconf_sx, SA_LOCKED); 118 if (!strcmp(name, "ffs")) 119 name = "ufs"; 120 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) { 121 if (!strcmp(name, vfsp->vfc_name)) 122 return (vfsp); 123 } 124 return (NULL); 125 } 126 127 struct vfsconf * 128 vfs_byname(const char *name) 129 { 130 struct vfsconf *vfsp; 131 132 vfsconf_slock(); 133 vfsp = vfs_byname_locked(name); 134 vfsconf_sunlock(); 135 return (vfsp); 136 } 137 138 struct vfsconf * 139 vfs_byname_kld(const char *fstype, struct thread *td, int *error) 140 { 141 struct vfsconf *vfsp; 142 int fileid, loaded; 143 144 vfsp = vfs_byname(fstype); 145 if (vfsp != NULL) 146 return (vfsp); 147 148 /* Try to load the respective module. */ 149 *error = kern_kldload(td, fstype, &fileid); 150 loaded = (*error == 0); 151 if (*error == EEXIST) 152 *error = 0; 153 if (*error) 154 return (NULL); 155 156 /* Look up again to see if the VFS was loaded. */ 157 vfsp = vfs_byname(fstype); 158 if (vfsp == NULL) { 159 if (loaded) 160 (void)kern_kldunload(td, fileid, LINKER_UNLOAD_FORCE); 161 *error = ENODEV; 162 return (NULL); 163 } 164 return (vfsp); 165 } 166 167 168 /* Register a new filesystem type in the global table */ 169 static int 170 vfs_register(struct vfsconf *vfc) 171 { 172 struct sysctl_oid *oidp; 173 struct vfsops *vfsops; 174 static int once; 175 struct vfsconf *tvfc; 176 uint32_t hashval; 177 int secondpass; 178 179 if (!once) { 180 vattr_null(&va_null); 181 once = 1; 182 } 183 184 if (vfc->vfc_version != VFS_VERSION) { 185 printf("ERROR: filesystem %s, unsupported ABI version %x\n", 186 vfc->vfc_name, vfc->vfc_version); 187 return (EINVAL); 188 } 189 vfsconf_lock(); 190 if (vfs_byname_locked(vfc->vfc_name) != NULL) { 191 vfsconf_unlock(); 192 return (EEXIST); 193 } 194 195 if (vfs_typenumhash != 0) { 196 /* 197 * Calculate a hash on vfc_name to use for vfc_typenum. Unless 198 * all of 1<->255 are assigned, it is limited to 8bits since 199 * that is what ZFS uses from vfc_typenum and is also the 200 * preferred range for vfs_getnewfsid(). 201 */ 202 hashval = fnv_32_str(vfc->vfc_name, FNV1_32_INIT); 203 hashval &= 0xff; 204 secondpass = 0; 205 do { 206 /* Look for and fix any collision. */ 207 TAILQ_FOREACH(tvfc, &vfsconf, vfc_list) { 208 if (hashval == tvfc->vfc_typenum) { 209 if (hashval == 255 && secondpass == 0) { 210 hashval = 1; 211 secondpass = 1; 212 } else 213 hashval++; 214 break; 215 } 216 } 217 } while (tvfc != NULL); 218 vfc->vfc_typenum = hashval; 219 if (vfc->vfc_typenum >= maxvfsconf) 220 maxvfsconf = vfc->vfc_typenum + 1; 221 } else 222 vfc->vfc_typenum = maxvfsconf++; 223 TAILQ_INSERT_TAIL(&vfsconf, vfc, vfc_list); 224 225 /* 226 * Initialise unused ``struct vfsops'' fields, to use 227 * the vfs_std*() functions. Note, we need the mount 228 * and unmount operations, at the least. The check 229 * for vfsops available is just a debugging aid. 230 */ 231 KASSERT(vfc->vfc_vfsops != NULL, 232 ("Filesystem %s has no vfsops", vfc->vfc_name)); 233 /* 234 * Check the mount and unmount operations. 235 */ 236 vfsops = vfc->vfc_vfsops; 237 KASSERT(vfsops->vfs_mount != NULL, 238 ("Filesystem %s has no mount op", vfc->vfc_name)); 239 KASSERT(vfsops->vfs_unmount != NULL, 240 ("Filesystem %s has no unmount op", vfc->vfc_name)); 241 242 if (vfsops->vfs_root == NULL) 243 /* return file system's root vnode */ 244 vfsops->vfs_root = vfs_stdroot; 245 if (vfsops->vfs_quotactl == NULL) 246 /* quota control */ 247 vfsops->vfs_quotactl = vfs_stdquotactl; 248 if (vfsops->vfs_statfs == NULL) 249 /* return file system's status */ 250 vfsops->vfs_statfs = vfs_stdstatfs; 251 if (vfsops->vfs_sync == NULL) 252 /* 253 * flush unwritten data (nosync) 254 * file systems can use vfs_stdsync 255 * explicitly by setting it in the 256 * vfsop vector. 257 */ 258 vfsops->vfs_sync = vfs_stdnosync; 259 if (vfsops->vfs_vget == NULL) 260 /* convert an inode number to a vnode */ 261 vfsops->vfs_vget = vfs_stdvget; 262 if (vfsops->vfs_fhtovp == NULL) 263 /* turn an NFS file handle into a vnode */ 264 vfsops->vfs_fhtovp = vfs_stdfhtovp; 265 if (vfsops->vfs_checkexp == NULL) 266 /* check if file system is exported */ 267 vfsops->vfs_checkexp = vfs_stdcheckexp; 268 if (vfsops->vfs_init == NULL) 269 /* file system specific initialisation */ 270 vfsops->vfs_init = vfs_stdinit; 271 if (vfsops->vfs_uninit == NULL) 272 /* file system specific uninitialisation */ 273 vfsops->vfs_uninit = vfs_stduninit; 274 if (vfsops->vfs_extattrctl == NULL) 275 /* extended attribute control */ 276 vfsops->vfs_extattrctl = vfs_stdextattrctl; 277 if (vfsops->vfs_sysctl == NULL) 278 vfsops->vfs_sysctl = vfs_stdsysctl; 279 280 /* 281 * Call init function for this VFS... 282 */ 283 (*(vfc->vfc_vfsops->vfs_init))(vfc); 284 vfsconf_unlock(); 285 286 /* 287 * If this filesystem has a sysctl node under vfs 288 * (i.e. vfs.xxfs), then change the oid number of that node to 289 * match the filesystem's type number. This allows user code 290 * which uses the type number to read sysctl variables defined 291 * by the filesystem to continue working. Since the oids are 292 * in a sorted list, we need to make sure the order is 293 * preserved by re-registering the oid after modifying its 294 * number. 295 */ 296 sysctl_wlock(); 297 SLIST_FOREACH(oidp, SYSCTL_CHILDREN(&sysctl___vfs), oid_link) { 298 if (strcmp(oidp->oid_name, vfc->vfc_name) == 0) { 299 sysctl_unregister_oid(oidp); 300 oidp->oid_number = vfc->vfc_typenum; 301 sysctl_register_oid(oidp); 302 break; 303 } 304 } 305 sysctl_wunlock(); 306 307 return (0); 308 } 309 310 311 /* Remove registration of a filesystem type */ 312 static int 313 vfs_unregister(struct vfsconf *vfc) 314 { 315 struct vfsconf *vfsp; 316 int error, maxtypenum; 317 318 vfsconf_lock(); 319 vfsp = vfs_byname_locked(vfc->vfc_name); 320 if (vfsp == NULL) { 321 vfsconf_unlock(); 322 return (EINVAL); 323 } 324 if (vfsp->vfc_refcount != 0) { 325 vfsconf_unlock(); 326 return (EBUSY); 327 } 328 if (vfc->vfc_vfsops->vfs_uninit != NULL) { 329 error = (*vfc->vfc_vfsops->vfs_uninit)(vfsp); 330 if (error != 0) { 331 vfsconf_unlock(); 332 return (error); 333 } 334 } 335 TAILQ_REMOVE(&vfsconf, vfsp, vfc_list); 336 maxtypenum = VFS_GENERIC; 337 TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) 338 if (maxtypenum < vfsp->vfc_typenum) 339 maxtypenum = vfsp->vfc_typenum; 340 maxvfsconf = maxtypenum + 1; 341 vfsconf_unlock(); 342 return (0); 343 } 344 345 /* 346 * Standard kernel module handling code for filesystem modules. 347 * Referenced from VFS_SET(). 348 */ 349 int 350 vfs_modevent(module_t mod, int type, void *data) 351 { 352 struct vfsconf *vfc; 353 int error = 0; 354 355 vfc = (struct vfsconf *)data; 356 357 switch (type) { 358 case MOD_LOAD: 359 if (vfc) 360 error = vfs_register(vfc); 361 break; 362 363 case MOD_UNLOAD: 364 if (vfc) 365 error = vfs_unregister(vfc); 366 break; 367 default: 368 error = EOPNOTSUPP; 369 break; 370 } 371 return (error); 372 } 373