1 /* $NetBSD: vfs_init.c,v 1.36 2007/11/07 00:23:25 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 2000 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 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /* 41 * Copyright (c) 1989, 1993 42 * The Regents of the University of California. All rights reserved. 43 * 44 * This code is derived from software contributed 45 * to Berkeley by John Heidemann of the UCLA Ficus project. 46 * 47 * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project 48 * 49 * Redistribution and use in source and binary forms, with or without 50 * modification, are permitted provided that the following conditions 51 * are met: 52 * 1. Redistributions of source code must retain the above copyright 53 * notice, this list of conditions and the following disclaimer. 54 * 2. Redistributions in binary form must reproduce the above copyright 55 * notice, this list of conditions and the following disclaimer in the 56 * documentation and/or other materials provided with the distribution. 57 * 3. Neither the name of the University nor the names of its contributors 58 * may be used to endorse or promote products derived from this software 59 * without specific prior written permission. 60 * 61 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 62 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 63 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 64 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 65 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 66 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 67 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 68 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 69 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 70 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 71 * SUCH DAMAGE. 72 * 73 * @(#)vfs_init.c 8.5 (Berkeley) 5/11/95 74 */ 75 76 #include <sys/cdefs.h> 77 __KERNEL_RCSID(0, "$NetBSD: vfs_init.c,v 1.36 2007/11/07 00:23:25 ad Exp $"); 78 79 #include <sys/param.h> 80 #include <sys/mount.h> 81 #include <sys/time.h> 82 #include <sys/vnode.h> 83 #include <sys/stat.h> 84 #include <sys/namei.h> 85 #include <sys/ucred.h> 86 #include <sys/buf.h> 87 #include <sys/errno.h> 88 #include <sys/malloc.h> 89 #include <sys/systm.h> 90 91 /* 92 * Sigh, such primitive tools are these... 93 */ 94 #if 0 95 #define DODEBUG(A) A 96 #else 97 #define DODEBUG(A) 98 #endif 99 100 /* 101 * The global list of vnode operations. 102 */ 103 extern const struct vnodeop_desc * const vfs_op_descs[]; 104 105 /* 106 * These vnodeopv_descs are listed here because they are not 107 * associated with any particular file system, and thus cannot 108 * be initialized by vfs_attach(). 109 */ 110 extern const struct vnodeopv_desc dead_vnodeop_opv_desc; 111 extern const struct vnodeopv_desc fifo_vnodeop_opv_desc; 112 extern const struct vnodeopv_desc spec_vnodeop_opv_desc; 113 extern const struct vnodeopv_desc sync_vnodeop_opv_desc; 114 115 const struct vnodeopv_desc * const vfs_special_vnodeopv_descs[] = { 116 &dead_vnodeop_opv_desc, 117 &fifo_vnodeop_opv_desc, 118 &spec_vnodeop_opv_desc, 119 &sync_vnodeop_opv_desc, 120 NULL, 121 }; 122 123 struct vfs_list_head vfs_list = /* vfs list */ 124 LIST_HEAD_INITIALIZER(vfs_list); 125 126 /* 127 * This code doesn't work if the defn is **vnodop_defns with cc. 128 * The problem is because of the compiler sometimes putting in an 129 * extra level of indirection for arrays. It's an interesting 130 * "feature" of C. 131 */ 132 typedef int (*PFI)(void *); 133 134 /* 135 * A miscellaneous routine. 136 * A generic "default" routine that just returns an error. 137 */ 138 /*ARGSUSED*/ 139 int 140 vn_default_error(void *v) 141 { 142 143 return (EOPNOTSUPP); 144 } 145 146 /* 147 * vfs_init.c 148 * 149 * Allocate and fill in operations vectors. 150 * 151 * An undocumented feature of this approach to defining operations is that 152 * there can be multiple entries in vfs_opv_descs for the same operations 153 * vector. This allows third parties to extend the set of operations 154 * supported by another layer in a binary compatibile way. For example, 155 * assume that NFS needed to be modified to support Ficus. NFS has an entry 156 * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by 157 * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions) 158 * listing those new operations Ficus adds to NFS, all without modifying the 159 * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but 160 * that is a(whole)nother story.) This is a feature. 161 */ 162 163 /* 164 * Init the vector, if it needs it. 165 * Also handle backwards compatibility. 166 */ 167 static void 168 vfs_opv_init_explicit(const struct vnodeopv_desc *vfs_opv_desc) 169 { 170 int (**opv_desc_vector)(void *); 171 const struct vnodeopv_entry_desc *opve_descp; 172 173 opv_desc_vector = *(vfs_opv_desc->opv_desc_vector_p); 174 175 for (opve_descp = vfs_opv_desc->opv_desc_ops; 176 opve_descp->opve_op; 177 opve_descp++) { 178 /* 179 * Sanity check: is this operation listed 180 * in the list of operations? We check this 181 * by seeing if its offset is zero. Since 182 * the default routine should always be listed 183 * first, it should be the only one with a zero 184 * offset. Any other operation with a zero 185 * offset is probably not listed in 186 * vfs_op_descs, and so is probably an error. 187 * 188 * A panic here means the layer programmer 189 * has committed the all-too common bug 190 * of adding a new operation to the layer's 191 * list of vnode operations but 192 * not adding the operation to the system-wide 193 * list of supported operations. 194 */ 195 if (opve_descp->opve_op->vdesc_offset == 0 && 196 opve_descp->opve_op->vdesc_offset != VOFFSET(vop_default)) { 197 printf("operation %s not listed in %s.\n", 198 opve_descp->opve_op->vdesc_name, "vfs_op_descs"); 199 panic ("vfs_opv_init: bad operation"); 200 } 201 202 /* 203 * Fill in this entry. 204 */ 205 opv_desc_vector[opve_descp->opve_op->vdesc_offset] = 206 opve_descp->opve_impl; 207 } 208 } 209 210 static void 211 vfs_opv_init_default(const struct vnodeopv_desc *vfs_opv_desc) 212 { 213 int j; 214 int (**opv_desc_vector)(void *); 215 216 opv_desc_vector = *(vfs_opv_desc->opv_desc_vector_p); 217 218 /* 219 * Force every operations vector to have a default routine. 220 */ 221 if (opv_desc_vector[VOFFSET(vop_default)] == NULL) 222 panic("vfs_opv_init: operation vector without default routine."); 223 224 for (j = 0; j < VNODE_OPS_COUNT; j++) 225 if (opv_desc_vector[j] == NULL) 226 opv_desc_vector[j] = 227 opv_desc_vector[VOFFSET(vop_default)]; 228 } 229 230 void 231 vfs_opv_init(const struct vnodeopv_desc * const *vopvdpp) 232 { 233 int (**opv_desc_vector)(void *); 234 int i; 235 236 /* 237 * Allocate the vectors. 238 */ 239 for (i = 0; vopvdpp[i] != NULL; i++) { 240 /* XXX - shouldn't be M_VNODE */ 241 opv_desc_vector = 242 malloc(VNODE_OPS_COUNT * sizeof(PFI), M_VNODE, M_WAITOK); 243 memset(opv_desc_vector, 0, VNODE_OPS_COUNT * sizeof(PFI)); 244 *(vopvdpp[i]->opv_desc_vector_p) = opv_desc_vector; 245 DODEBUG(printf("vector at %p allocated\n", 246 opv_desc_vector_p)); 247 } 248 249 /* 250 * ...and fill them in. 251 */ 252 for (i = 0; vopvdpp[i] != NULL; i++) 253 vfs_opv_init_explicit(vopvdpp[i]); 254 255 /* 256 * Finally, go back and replace unfilled routines 257 * with their default. 258 */ 259 for (i = 0; vopvdpp[i] != NULL; i++) 260 vfs_opv_init_default(vopvdpp[i]); 261 } 262 263 void 264 vfs_opv_free(const struct vnodeopv_desc * const *vopvdpp) 265 { 266 int i; 267 268 /* 269 * Free the vectors allocated in vfs_opv_init(). 270 */ 271 for (i = 0; vopvdpp[i] != NULL; i++) { 272 /* XXX - shouldn't be M_VNODE */ 273 free(*(vopvdpp[i]->opv_desc_vector_p), M_VNODE); 274 *(vopvdpp[i]->opv_desc_vector_p) = NULL; 275 } 276 } 277 278 #ifdef DEBUG 279 static void 280 vfs_op_check(void) 281 { 282 int i; 283 284 DODEBUG(printf("Vnode_interface_init.\n")); 285 286 /* 287 * Check offset of each op. 288 */ 289 for (i = 0; vfs_op_descs[i]; i++) { 290 if (vfs_op_descs[i]->vdesc_offset != i) 291 panic("vfs_op_check: vfs_op_desc[] offset mismatch"); 292 } 293 294 if (i != VNODE_OPS_COUNT) { 295 panic("vfs_op_check: vnode ops count mismatch (%d != %d)", 296 i, VNODE_OPS_COUNT); 297 } 298 299 DODEBUG(printf ("vfs_opv_numops=%d\n", VNODE_OPS_COUNT)); 300 } 301 #endif /* DEBUG */ 302 303 /* 304 * Initialize the vnode structures and initialize each file system type. 305 */ 306 void 307 vfsinit(void) 308 { 309 __link_set_decl(vfsops, struct vfsops); 310 struct vfsops * const *vfsp; 311 312 /* 313 * Initialize the namei pathname buffer pool and cache. 314 */ 315 pnbuf_cache = pool_cache_init(MAXPATHLEN, 0, 0, 0, "pnbufpl", 316 NULL, IPL_NONE, NULL, NULL, NULL); 317 KASSERT(pnbuf_cache != NULL); 318 319 /* 320 * Initialize the vnode table 321 */ 322 vntblinit(); 323 324 /* 325 * Initialize the vnode name cache 326 */ 327 nchinit(); 328 329 #ifdef DEBUG 330 /* 331 * Check the list of vnode operations. 332 */ 333 vfs_op_check(); 334 #endif 335 336 /* 337 * Initialize the special vnode operations. 338 */ 339 vfs_opv_init(vfs_special_vnodeopv_descs); 340 341 /* 342 * Establish each file system which was statically 343 * included in the kernel. 344 */ 345 __link_set_foreach(vfsp, vfsops) { 346 if (vfs_attach(*vfsp)) { 347 printf("multiple `%s' file systems", 348 (*vfsp)->vfs_name); 349 panic("vfsinit"); 350 } 351 } 352 } 353 354 /* 355 * Drop a reference to a file system type. 356 */ 357 void 358 vfs_delref(struct vfsops *vfs) 359 { 360 361 mutex_enter(&vfs_list_lock); 362 vfs->vfs_refcount--; 363 mutex_exit(&vfs_list_lock); 364 } 365 366 /* 367 * Establish a file system and initialize it. 368 */ 369 int 370 vfs_attach(struct vfsops *vfs) 371 { 372 struct vfsops *v; 373 int error = 0; 374 375 mutex_enter(&vfs_list_lock); 376 377 /* 378 * Make sure this file system doesn't already exist. 379 */ 380 LIST_FOREACH(v, &vfs_list, vfs_list) { 381 if (strcmp(vfs->vfs_name, v->vfs_name) == 0) { 382 error = EEXIST; 383 goto out; 384 } 385 } 386 387 /* 388 * Initialize the vnode operations for this file system. 389 */ 390 vfs_opv_init(vfs->vfs_opv_descs); 391 392 /* 393 * Now initialize the file system itself. 394 */ 395 (*vfs->vfs_init)(); 396 397 /* 398 * ...and link it into the kernel's list. 399 */ 400 LIST_INSERT_HEAD(&vfs_list, vfs, vfs_list); 401 402 /* 403 * Sanity: make sure the reference count is 0. 404 */ 405 vfs->vfs_refcount = 0; 406 out: 407 mutex_exit(&vfs_list_lock); 408 return (error); 409 } 410 411 /* 412 * Remove a file system from the kernel. 413 */ 414 int 415 vfs_detach(struct vfsops *vfs) 416 { 417 struct vfsops *v; 418 int error = 0; 419 420 mutex_enter(&vfs_list_lock); 421 422 /* 423 * Make sure no one is using the filesystem. 424 */ 425 if (vfs->vfs_refcount != 0) { 426 error = EBUSY; 427 goto out; 428 } 429 430 /* 431 * ...and remove it from the kernel's list. 432 */ 433 LIST_FOREACH(v, &vfs_list, vfs_list) { 434 if (v == vfs) { 435 LIST_REMOVE(v, vfs_list); 436 break; 437 } 438 } 439 440 if (v == NULL) { 441 error = ESRCH; 442 goto out; 443 } 444 445 /* 446 * Now run the file system-specific cleanups. 447 */ 448 (*vfs->vfs_done)(); 449 450 /* 451 * Free the vnode operations vector. 452 */ 453 vfs_opv_free(vfs->vfs_opv_descs); 454 out: 455 mutex_exit(&vfs_list_lock); 456 return (error); 457 } 458 459 void 460 vfs_reinit(void) 461 { 462 struct vfsops *vfs; 463 464 mutex_enter(&vfs_list_lock); 465 LIST_FOREACH(vfs, &vfs_list, vfs_list) { 466 if (vfs->vfs_reinit) { 467 vfs->vfs_refcount++; 468 mutex_exit(&vfs_list_lock); 469 (*vfs->vfs_reinit)(); 470 mutex_enter(&vfs_list_lock); 471 vfs->vfs_refcount--; 472 } 473 } 474 mutex_exit(&vfs_list_lock); 475 } 476