1 /* $NetBSD: vfs_init.c,v 1.41 2008/09/27 13:01:07 reinoud Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 2000, 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * Copyright (c) 1989, 1993 35 * The Regents of the University of California. All rights reserved. 36 * 37 * This code is derived from software contributed 38 * to Berkeley by John Heidemann of the UCLA Ficus project. 39 * 40 * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project 41 * 42 * Redistribution and use in source and binary forms, with or without 43 * modification, are permitted provided that the following conditions 44 * are met: 45 * 1. Redistributions of source code must retain the above copyright 46 * notice, this list of conditions and the following disclaimer. 47 * 2. Redistributions in binary form must reproduce the above copyright 48 * notice, this list of conditions and the following disclaimer in the 49 * documentation and/or other materials provided with the distribution. 50 * 3. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 * 66 * @(#)vfs_init.c 8.5 (Berkeley) 5/11/95 67 */ 68 69 #include <sys/cdefs.h> 70 __KERNEL_RCSID(0, "$NetBSD: vfs_init.c,v 1.41 2008/09/27 13:01:07 reinoud Exp $"); 71 72 #include <sys/param.h> 73 #include <sys/mount.h> 74 #include <sys/time.h> 75 #include <sys/vnode.h> 76 #include <sys/stat.h> 77 #include <sys/namei.h> 78 #include <sys/ucred.h> 79 #include <sys/buf.h> 80 #include <sys/errno.h> 81 #include <sys/malloc.h> 82 #include <sys/systm.h> 83 #include <sys/module.h> 84 #include <sys/dirhash.h> 85 86 /* 87 * Sigh, such primitive tools are these... 88 */ 89 #if 0 90 #define DODEBUG(A) A 91 #else 92 #define DODEBUG(A) 93 #endif 94 95 /* 96 * The global list of vnode operations. 97 */ 98 extern const struct vnodeop_desc * const vfs_op_descs[]; 99 100 /* 101 * These vnodeopv_descs are listed here because they are not 102 * associated with any particular file system, and thus cannot 103 * be initialized by vfs_attach(). 104 */ 105 extern const struct vnodeopv_desc dead_vnodeop_opv_desc; 106 extern const struct vnodeopv_desc fifo_vnodeop_opv_desc; 107 extern const struct vnodeopv_desc spec_vnodeop_opv_desc; 108 extern const struct vnodeopv_desc sync_vnodeop_opv_desc; 109 110 const struct vnodeopv_desc * const vfs_special_vnodeopv_descs[] = { 111 &dead_vnodeop_opv_desc, 112 &fifo_vnodeop_opv_desc, 113 &spec_vnodeop_opv_desc, 114 &sync_vnodeop_opv_desc, 115 NULL, 116 }; 117 118 struct vfs_list_head vfs_list = /* vfs list */ 119 LIST_HEAD_INITIALIZER(vfs_list); 120 121 /* 122 * This code doesn't work if the defn is **vnodop_defns with cc. 123 * The problem is because of the compiler sometimes putting in an 124 * extra level of indirection for arrays. It's an interesting 125 * "feature" of C. 126 */ 127 typedef int (*PFI)(void *); 128 129 /* 130 * A miscellaneous routine. 131 * A generic "default" routine that just returns an error. 132 */ 133 /*ARGSUSED*/ 134 int 135 vn_default_error(void *v) 136 { 137 138 return (EOPNOTSUPP); 139 } 140 141 /* 142 * vfs_init.c 143 * 144 * Allocate and fill in operations vectors. 145 * 146 * An undocumented feature of this approach to defining operations is that 147 * there can be multiple entries in vfs_opv_descs for the same operations 148 * vector. This allows third parties to extend the set of operations 149 * supported by another layer in a binary compatibile way. For example, 150 * assume that NFS needed to be modified to support Ficus. NFS has an entry 151 * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by 152 * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions) 153 * listing those new operations Ficus adds to NFS, all without modifying the 154 * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but 155 * that is a(whole)nother story.) This is a feature. 156 */ 157 158 /* 159 * Init the vector, if it needs it. 160 * Also handle backwards compatibility. 161 */ 162 static void 163 vfs_opv_init_explicit(const struct vnodeopv_desc *vfs_opv_desc) 164 { 165 int (**opv_desc_vector)(void *); 166 const struct vnodeopv_entry_desc *opve_descp; 167 168 opv_desc_vector = *(vfs_opv_desc->opv_desc_vector_p); 169 170 for (opve_descp = vfs_opv_desc->opv_desc_ops; 171 opve_descp->opve_op; 172 opve_descp++) { 173 /* 174 * Sanity check: is this operation listed 175 * in the list of operations? We check this 176 * by seeing if its offset is zero. Since 177 * the default routine should always be listed 178 * first, it should be the only one with a zero 179 * offset. Any other operation with a zero 180 * offset is probably not listed in 181 * vfs_op_descs, and so is probably an error. 182 * 183 * A panic here means the layer programmer 184 * has committed the all-too common bug 185 * of adding a new operation to the layer's 186 * list of vnode operations but 187 * not adding the operation to the system-wide 188 * list of supported operations. 189 */ 190 if (opve_descp->opve_op->vdesc_offset == 0 && 191 opve_descp->opve_op->vdesc_offset != VOFFSET(vop_default)) { 192 printf("operation %s not listed in %s.\n", 193 opve_descp->opve_op->vdesc_name, "vfs_op_descs"); 194 panic ("vfs_opv_init: bad operation"); 195 } 196 197 /* 198 * Fill in this entry. 199 */ 200 opv_desc_vector[opve_descp->opve_op->vdesc_offset] = 201 opve_descp->opve_impl; 202 } 203 } 204 205 static void 206 vfs_opv_init_default(const struct vnodeopv_desc *vfs_opv_desc) 207 { 208 int j; 209 int (**opv_desc_vector)(void *); 210 211 opv_desc_vector = *(vfs_opv_desc->opv_desc_vector_p); 212 213 /* 214 * Force every operations vector to have a default routine. 215 */ 216 if (opv_desc_vector[VOFFSET(vop_default)] == NULL) 217 panic("vfs_opv_init: operation vector without default routine."); 218 219 for (j = 0; j < VNODE_OPS_COUNT; j++) 220 if (opv_desc_vector[j] == NULL) 221 opv_desc_vector[j] = 222 opv_desc_vector[VOFFSET(vop_default)]; 223 } 224 225 void 226 vfs_opv_init(const struct vnodeopv_desc * const *vopvdpp) 227 { 228 int (**opv_desc_vector)(void *); 229 int i; 230 231 /* 232 * Allocate the vectors. 233 */ 234 for (i = 0; vopvdpp[i] != NULL; i++) { 235 /* XXX - shouldn't be M_VNODE */ 236 opv_desc_vector = 237 malloc(VNODE_OPS_COUNT * sizeof(PFI), M_VNODE, M_WAITOK); 238 memset(opv_desc_vector, 0, VNODE_OPS_COUNT * sizeof(PFI)); 239 *(vopvdpp[i]->opv_desc_vector_p) = opv_desc_vector; 240 DODEBUG(printf("vector at %p allocated\n", 241 opv_desc_vector_p)); 242 } 243 244 /* 245 * ...and fill them in. 246 */ 247 for (i = 0; vopvdpp[i] != NULL; i++) 248 vfs_opv_init_explicit(vopvdpp[i]); 249 250 /* 251 * Finally, go back and replace unfilled routines 252 * with their default. 253 */ 254 for (i = 0; vopvdpp[i] != NULL; i++) 255 vfs_opv_init_default(vopvdpp[i]); 256 } 257 258 void 259 vfs_opv_free(const struct vnodeopv_desc * const *vopvdpp) 260 { 261 int i; 262 263 /* 264 * Free the vectors allocated in vfs_opv_init(). 265 */ 266 for (i = 0; vopvdpp[i] != NULL; i++) { 267 /* XXX - shouldn't be M_VNODE */ 268 free(*(vopvdpp[i]->opv_desc_vector_p), M_VNODE); 269 *(vopvdpp[i]->opv_desc_vector_p) = NULL; 270 } 271 } 272 273 #ifdef DEBUG 274 static void 275 vfs_op_check(void) 276 { 277 int i; 278 279 DODEBUG(printf("Vnode_interface_init.\n")); 280 281 /* 282 * Check offset of each op. 283 */ 284 for (i = 0; vfs_op_descs[i]; i++) { 285 if (vfs_op_descs[i]->vdesc_offset != i) 286 panic("vfs_op_check: vfs_op_desc[] offset mismatch"); 287 } 288 289 if (i != VNODE_OPS_COUNT) { 290 panic("vfs_op_check: vnode ops count mismatch (%d != %d)", 291 i, VNODE_OPS_COUNT); 292 } 293 294 DODEBUG(printf ("vfs_opv_numops=%d\n", VNODE_OPS_COUNT)); 295 } 296 #endif /* DEBUG */ 297 298 /* 299 * Initialize the vnode structures and initialize each file system type. 300 */ 301 void 302 vfsinit(void) 303 { 304 305 /* 306 * Initialize the namei pathname buffer pool and cache. 307 */ 308 pnbuf_cache = pool_cache_init(MAXPATHLEN, 0, 0, 0, "pnbufpl", 309 NULL, IPL_NONE, NULL, NULL, NULL); 310 KASSERT(pnbuf_cache != NULL); 311 312 /* 313 * Initialize the vnode table 314 */ 315 vntblinit(); 316 317 /* 318 * Initialize the vnode name cache 319 */ 320 nchinit(); 321 322 #ifdef DEBUG 323 /* 324 * Check the list of vnode operations. 325 */ 326 vfs_op_check(); 327 #endif 328 329 /* 330 * Initialize the special vnode operations. 331 */ 332 vfs_opv_init(vfs_special_vnodeopv_descs); 333 334 /* 335 * Initialise generic dirhash. 336 */ 337 dirhash_init(); 338 339 /* 340 * Initialise VFS hooks. 341 */ 342 vfs_hooks_init(); 343 344 /* 345 * Establish each file system which was statically 346 * included in the kernel. 347 */ 348 module_init_class(MODULE_CLASS_VFS); 349 } 350 351 /* 352 * Drop a reference to a file system type. 353 */ 354 void 355 vfs_delref(struct vfsops *vfs) 356 { 357 358 mutex_enter(&vfs_list_lock); 359 vfs->vfs_refcount--; 360 mutex_exit(&vfs_list_lock); 361 } 362 363 /* 364 * Establish a file system and initialize it. 365 */ 366 int 367 vfs_attach(struct vfsops *vfs) 368 { 369 struct vfsops *v; 370 int error = 0; 371 372 mutex_enter(&vfs_list_lock); 373 374 /* 375 * Make sure this file system doesn't already exist. 376 */ 377 LIST_FOREACH(v, &vfs_list, vfs_list) { 378 if (strcmp(vfs->vfs_name, v->vfs_name) == 0) { 379 error = EEXIST; 380 goto out; 381 } 382 } 383 384 /* 385 * Initialize the vnode operations for this file system. 386 */ 387 vfs_opv_init(vfs->vfs_opv_descs); 388 389 /* 390 * Now initialize the file system itself. 391 */ 392 (*vfs->vfs_init)(); 393 394 /* 395 * ...and link it into the kernel's list. 396 */ 397 LIST_INSERT_HEAD(&vfs_list, vfs, vfs_list); 398 399 /* 400 * Sanity: make sure the reference count is 0. 401 */ 402 vfs->vfs_refcount = 0; 403 out: 404 mutex_exit(&vfs_list_lock); 405 return (error); 406 } 407 408 /* 409 * Remove a file system from the kernel. 410 */ 411 int 412 vfs_detach(struct vfsops *vfs) 413 { 414 struct vfsops *v; 415 int error = 0; 416 417 mutex_enter(&vfs_list_lock); 418 419 /* 420 * Make sure no one is using the filesystem. 421 */ 422 if (vfs->vfs_refcount != 0) { 423 error = EBUSY; 424 goto out; 425 } 426 427 /* 428 * ...and remove it from the kernel's list. 429 */ 430 LIST_FOREACH(v, &vfs_list, vfs_list) { 431 if (v == vfs) { 432 LIST_REMOVE(v, vfs_list); 433 break; 434 } 435 } 436 437 if (v == NULL) { 438 error = ESRCH; 439 goto out; 440 } 441 442 /* 443 * Now run the file system-specific cleanups. 444 */ 445 (*vfs->vfs_done)(); 446 447 /* 448 * Free the vnode operations vector. 449 */ 450 vfs_opv_free(vfs->vfs_opv_descs); 451 out: 452 mutex_exit(&vfs_list_lock); 453 return (error); 454 } 455 456 void 457 vfs_reinit(void) 458 { 459 struct vfsops *vfs; 460 461 mutex_enter(&vfs_list_lock); 462 LIST_FOREACH(vfs, &vfs_list, vfs_list) { 463 if (vfs->vfs_reinit) { 464 vfs->vfs_refcount++; 465 mutex_exit(&vfs_list_lock); 466 (*vfs->vfs_reinit)(); 467 mutex_enter(&vfs_list_lock); 468 vfs->vfs_refcount--; 469 } 470 } 471 mutex_exit(&vfs_list_lock); 472 } 473