1 /* $NetBSD: vfs_init.c,v 1.40 2008/05/10 02:26:09 rumble 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 1.40 2008/05/10 02:26:09 rumble 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 85 /* 86 * Sigh, such primitive tools are these... 87 */ 88 #if 0 89 #define DODEBUG(A) A 90 #else 91 #define DODEBUG(A) 92 #endif 93 94 /* 95 * The global list of vnode operations. 96 */ 97 extern const struct vnodeop_desc * const vfs_op_descs[]; 98 99 /* 100 * These vnodeopv_descs are listed here because they are not 101 * associated with any particular file system, and thus cannot 102 * be initialized by vfs_attach(). 103 */ 104 extern const struct vnodeopv_desc dead_vnodeop_opv_desc; 105 extern const struct vnodeopv_desc fifo_vnodeop_opv_desc; 106 extern const struct vnodeopv_desc spec_vnodeop_opv_desc; 107 extern const struct vnodeopv_desc sync_vnodeop_opv_desc; 108 109 const struct vnodeopv_desc * const vfs_special_vnodeopv_descs[] = { 110 &dead_vnodeop_opv_desc, 111 &fifo_vnodeop_opv_desc, 112 &spec_vnodeop_opv_desc, 113 &sync_vnodeop_opv_desc, 114 NULL, 115 }; 116 117 struct vfs_list_head vfs_list = /* vfs list */ 118 LIST_HEAD_INITIALIZER(vfs_list); 119 120 /* 121 * This code doesn't work if the defn is **vnodop_defns with cc. 122 * The problem is because of the compiler sometimes putting in an 123 * extra level of indirection for arrays. It's an interesting 124 * "feature" of C. 125 */ 126 typedef int (*PFI)(void *); 127 128 /* 129 * A miscellaneous routine. 130 * A generic "default" routine that just returns an error. 131 */ 132 /*ARGSUSED*/ 133 int 134 vn_default_error(void *v) 135 { 136 137 return (EOPNOTSUPP); 138 } 139 140 /* 141 * vfs_init.c 142 * 143 * Allocate and fill in operations vectors. 144 * 145 * An undocumented feature of this approach to defining operations is that 146 * there can be multiple entries in vfs_opv_descs for the same operations 147 * vector. This allows third parties to extend the set of operations 148 * supported by another layer in a binary compatibile way. For example, 149 * assume that NFS needed to be modified to support Ficus. NFS has an entry 150 * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by 151 * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions) 152 * listing those new operations Ficus adds to NFS, all without modifying the 153 * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but 154 * that is a(whole)nother story.) This is a feature. 155 */ 156 157 /* 158 * Init the vector, if it needs it. 159 * Also handle backwards compatibility. 160 */ 161 static void 162 vfs_opv_init_explicit(const struct vnodeopv_desc *vfs_opv_desc) 163 { 164 int (**opv_desc_vector)(void *); 165 const struct vnodeopv_entry_desc *opve_descp; 166 167 opv_desc_vector = *(vfs_opv_desc->opv_desc_vector_p); 168 169 for (opve_descp = vfs_opv_desc->opv_desc_ops; 170 opve_descp->opve_op; 171 opve_descp++) { 172 /* 173 * Sanity check: is this operation listed 174 * in the list of operations? We check this 175 * by seeing if its offset is zero. Since 176 * the default routine should always be listed 177 * first, it should be the only one with a zero 178 * offset. Any other operation with a zero 179 * offset is probably not listed in 180 * vfs_op_descs, and so is probably an error. 181 * 182 * A panic here means the layer programmer 183 * has committed the all-too common bug 184 * of adding a new operation to the layer's 185 * list of vnode operations but 186 * not adding the operation to the system-wide 187 * list of supported operations. 188 */ 189 if (opve_descp->opve_op->vdesc_offset == 0 && 190 opve_descp->opve_op->vdesc_offset != VOFFSET(vop_default)) { 191 printf("operation %s not listed in %s.\n", 192 opve_descp->opve_op->vdesc_name, "vfs_op_descs"); 193 panic ("vfs_opv_init: bad operation"); 194 } 195 196 /* 197 * Fill in this entry. 198 */ 199 opv_desc_vector[opve_descp->opve_op->vdesc_offset] = 200 opve_descp->opve_impl; 201 } 202 } 203 204 static void 205 vfs_opv_init_default(const struct vnodeopv_desc *vfs_opv_desc) 206 { 207 int j; 208 int (**opv_desc_vector)(void *); 209 210 opv_desc_vector = *(vfs_opv_desc->opv_desc_vector_p); 211 212 /* 213 * Force every operations vector to have a default routine. 214 */ 215 if (opv_desc_vector[VOFFSET(vop_default)] == NULL) 216 panic("vfs_opv_init: operation vector without default routine."); 217 218 for (j = 0; j < VNODE_OPS_COUNT; j++) 219 if (opv_desc_vector[j] == NULL) 220 opv_desc_vector[j] = 221 opv_desc_vector[VOFFSET(vop_default)]; 222 } 223 224 void 225 vfs_opv_init(const struct vnodeopv_desc * const *vopvdpp) 226 { 227 int (**opv_desc_vector)(void *); 228 int i; 229 230 /* 231 * Allocate the vectors. 232 */ 233 for (i = 0; vopvdpp[i] != NULL; i++) { 234 /* XXX - shouldn't be M_VNODE */ 235 opv_desc_vector = 236 malloc(VNODE_OPS_COUNT * sizeof(PFI), M_VNODE, M_WAITOK); 237 memset(opv_desc_vector, 0, VNODE_OPS_COUNT * sizeof(PFI)); 238 *(vopvdpp[i]->opv_desc_vector_p) = opv_desc_vector; 239 DODEBUG(printf("vector at %p allocated\n", 240 opv_desc_vector_p)); 241 } 242 243 /* 244 * ...and fill them in. 245 */ 246 for (i = 0; vopvdpp[i] != NULL; i++) 247 vfs_opv_init_explicit(vopvdpp[i]); 248 249 /* 250 * Finally, go back and replace unfilled routines 251 * with their default. 252 */ 253 for (i = 0; vopvdpp[i] != NULL; i++) 254 vfs_opv_init_default(vopvdpp[i]); 255 } 256 257 void 258 vfs_opv_free(const struct vnodeopv_desc * const *vopvdpp) 259 { 260 int i; 261 262 /* 263 * Free the vectors allocated in vfs_opv_init(). 264 */ 265 for (i = 0; vopvdpp[i] != NULL; i++) { 266 /* XXX - shouldn't be M_VNODE */ 267 free(*(vopvdpp[i]->opv_desc_vector_p), M_VNODE); 268 *(vopvdpp[i]->opv_desc_vector_p) = NULL; 269 } 270 } 271 272 #ifdef DEBUG 273 static void 274 vfs_op_check(void) 275 { 276 int i; 277 278 DODEBUG(printf("Vnode_interface_init.\n")); 279 280 /* 281 * Check offset of each op. 282 */ 283 for (i = 0; vfs_op_descs[i]; i++) { 284 if (vfs_op_descs[i]->vdesc_offset != i) 285 panic("vfs_op_check: vfs_op_desc[] offset mismatch"); 286 } 287 288 if (i != VNODE_OPS_COUNT) { 289 panic("vfs_op_check: vnode ops count mismatch (%d != %d)", 290 i, VNODE_OPS_COUNT); 291 } 292 293 DODEBUG(printf ("vfs_opv_numops=%d\n", VNODE_OPS_COUNT)); 294 } 295 #endif /* DEBUG */ 296 297 /* 298 * Initialize the vnode structures and initialize each file system type. 299 */ 300 void 301 vfsinit(void) 302 { 303 304 /* 305 * Initialize the namei pathname buffer pool and cache. 306 */ 307 pnbuf_cache = pool_cache_init(MAXPATHLEN, 0, 0, 0, "pnbufpl", 308 NULL, IPL_NONE, NULL, NULL, NULL); 309 KASSERT(pnbuf_cache != NULL); 310 311 /* 312 * Initialize the vnode table 313 */ 314 vntblinit(); 315 316 /* 317 * Initialize the vnode name cache 318 */ 319 nchinit(); 320 321 #ifdef DEBUG 322 /* 323 * Check the list of vnode operations. 324 */ 325 vfs_op_check(); 326 #endif 327 328 /* 329 * Initialize the special vnode operations. 330 */ 331 vfs_opv_init(vfs_special_vnodeopv_descs); 332 333 /* 334 * Initialise VFS hooks. 335 */ 336 vfs_hooks_init(); 337 338 /* 339 * Establish each file system which was statically 340 * included in the kernel. 341 */ 342 module_init_class(MODULE_CLASS_VFS); 343 } 344 345 /* 346 * Drop a reference to a file system type. 347 */ 348 void 349 vfs_delref(struct vfsops *vfs) 350 { 351 352 mutex_enter(&vfs_list_lock); 353 vfs->vfs_refcount--; 354 mutex_exit(&vfs_list_lock); 355 } 356 357 /* 358 * Establish a file system and initialize it. 359 */ 360 int 361 vfs_attach(struct vfsops *vfs) 362 { 363 struct vfsops *v; 364 int error = 0; 365 366 mutex_enter(&vfs_list_lock); 367 368 /* 369 * Make sure this file system doesn't already exist. 370 */ 371 LIST_FOREACH(v, &vfs_list, vfs_list) { 372 if (strcmp(vfs->vfs_name, v->vfs_name) == 0) { 373 error = EEXIST; 374 goto out; 375 } 376 } 377 378 /* 379 * Initialize the vnode operations for this file system. 380 */ 381 vfs_opv_init(vfs->vfs_opv_descs); 382 383 /* 384 * Now initialize the file system itself. 385 */ 386 (*vfs->vfs_init)(); 387 388 /* 389 * ...and link it into the kernel's list. 390 */ 391 LIST_INSERT_HEAD(&vfs_list, vfs, vfs_list); 392 393 /* 394 * Sanity: make sure the reference count is 0. 395 */ 396 vfs->vfs_refcount = 0; 397 out: 398 mutex_exit(&vfs_list_lock); 399 return (error); 400 } 401 402 /* 403 * Remove a file system from the kernel. 404 */ 405 int 406 vfs_detach(struct vfsops *vfs) 407 { 408 struct vfsops *v; 409 int error = 0; 410 411 mutex_enter(&vfs_list_lock); 412 413 /* 414 * Make sure no one is using the filesystem. 415 */ 416 if (vfs->vfs_refcount != 0) { 417 error = EBUSY; 418 goto out; 419 } 420 421 /* 422 * ...and remove it from the kernel's list. 423 */ 424 LIST_FOREACH(v, &vfs_list, vfs_list) { 425 if (v == vfs) { 426 LIST_REMOVE(v, vfs_list); 427 break; 428 } 429 } 430 431 if (v == NULL) { 432 error = ESRCH; 433 goto out; 434 } 435 436 /* 437 * Now run the file system-specific cleanups. 438 */ 439 (*vfs->vfs_done)(); 440 441 /* 442 * Free the vnode operations vector. 443 */ 444 vfs_opv_free(vfs->vfs_opv_descs); 445 out: 446 mutex_exit(&vfs_list_lock); 447 return (error); 448 } 449 450 void 451 vfs_reinit(void) 452 { 453 struct vfsops *vfs; 454 455 mutex_enter(&vfs_list_lock); 456 LIST_FOREACH(vfs, &vfs_list, vfs_list) { 457 if (vfs->vfs_reinit) { 458 vfs->vfs_refcount++; 459 mutex_exit(&vfs_list_lock); 460 (*vfs->vfs_reinit)(); 461 mutex_enter(&vfs_list_lock); 462 vfs->vfs_refcount--; 463 } 464 } 465 mutex_exit(&vfs_list_lock); 466 } 467