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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)vfs_init.c 8.3 (Berkeley) 1/4/94 39 * $FreeBSD$ 40 */ 41 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/kernel.h> 46 #include <sys/mount.h> 47 #include <sys/sysctl.h> 48 #include <sys/vnode.h> 49 #include <sys/malloc.h> 50 51 52 MALLOC_DEFINE(M_VNODE, "vnodes", "Dynamically allocated vnodes"); 53 54 /* 55 * The highest defined VFS number. 56 */ 57 int maxvfsconf = VFS_GENERIC + 1; 58 59 /* 60 * Single-linked list of configured VFSes. 61 * New entries are added/deleted by vfs_register()/vfs_unregister() 62 */ 63 struct vfsconf *vfsconf; 64 65 /* 66 * vfs_init.c 67 * 68 * Allocate and fill in operations vectors. 69 * 70 * An undocumented feature of this approach to defining operations is that 71 * there can be multiple entries in vfs_opv_descs for the same operations 72 * vector. This allows third parties to extend the set of operations 73 * supported by another layer in a binary compatibile way. For example, 74 * assume that NFS needed to be modified to support Ficus. NFS has an entry 75 * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by 76 * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions) 77 * listing those new operations Ficus adds to NFS, all without modifying the 78 * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but 79 * that is a(whole)nother story.) This is a feature. 80 */ 81 82 /* Table of known vnodeop vectors (list of VFS vnode vectors) */ 83 static const struct vnodeopv_desc **vnodeopv_descs; 84 static int vnodeopv_num; 85 86 /* Table of known descs (list of vnode op handlers "vop_access_desc") */ 87 static struct vnodeop_desc **vfs_op_descs; 88 /* Reference counts for vfs_op_descs */ 89 static int *vfs_op_desc_refs; 90 /* Number of descriptions */ 91 static int num_op_descs; 92 /* Number of entries in each description */ 93 static int vfs_opv_numops = 64; 94 95 /* Allow this number to be tuned at boot */ 96 TUNABLE_INT("vfs.opv_numops", &vfs_opv_numops); 97 SYSCTL_INT(_vfs, OID_AUTO, opv_numops, CTLFLAG_RD, &vfs_opv_numops, 98 0, "Maximum number of operations in vop_t vector"); 99 100 static int int_cmp(const void *a, const void *b); 101 102 static int 103 int_cmp(const void *a, const void *b) 104 { 105 return(*(const int *)a - *(const int *)b); 106 } 107 108 /* 109 * Recalculate the operations vector/description (those parts of it that can 110 * be recalculated, that is.) 111 * Always allocate operations vector large enough to hold vfs_opv_numops 112 * entries. The vector is never freed or deallocated once it is initialized, 113 * so that vnodes might safely reference it through their v_op pointer without 114 * vector changing suddenly from under them. 115 */ 116 static void 117 vfs_opv_recalc(void) 118 { 119 int i, j, k; 120 int *vfs_op_offsets; 121 vop_t ***opv_desc_vector_p; 122 vop_t **opv_desc_vector; 123 struct vnodeopv_entry_desc *opve_descp; 124 const struct vnodeopv_desc *opv; 125 126 if (vfs_op_descs == NULL) 127 panic("vfs_opv_recalc called with null vfs_op_descs"); 128 129 /* 130 * Allocate and initialize temporary array to store 131 * offsets. Sort it to put all uninitialized entries 132 * first and to make holes in existing offset sequence 133 * detectable. 134 */ 135 MALLOC(vfs_op_offsets, int *, 136 num_op_descs * sizeof(int), M_TEMP, M_WAITOK); 137 if (vfs_op_offsets == NULL) 138 panic("vfs_opv_recalc: no memory"); 139 for (i = 0; i < num_op_descs; i++) 140 vfs_op_offsets[i] = vfs_op_descs[i]->vdesc_offset; 141 qsort(vfs_op_offsets, num_op_descs, sizeof(int), int_cmp); 142 143 /* 144 * Run through and make sure all known descs have an offset. 145 * Use vfs_op_offsets to locate holes in offset sequence and 146 * reuse them. 147 * vop_default_desc is hardwired at offset 1, and offset 0 148 * is a panic sanity check. 149 */ 150 j = 1; k = 1; 151 for (i = 0; i < num_op_descs; i++) { 152 if (vfs_op_descs[i]->vdesc_offset != 0) 153 continue; 154 /* 155 * Look at two adjacent entries vfs_op_offsets[j - 1] and 156 * vfs_op_offsets[j] and see if we can fit a new offset 157 * number in between. If not, look at the next pair until 158 * hole is found or the end of the vfs_op_offsets vector is 159 * reached. j has been initialized to 1 above so that 160 * referencing (j-1)-th element is safe and the loop will 161 * never execute if num_op_descs is 1. For each new value s 162 * of i the j loop pick up from where previous iteration has 163 * left off. When the last hole has been consumed or if no 164 * hole has been found, we will start allocating new numbers 165 * starting from the biggest already available offset + 1. 166 */ 167 for (; j < num_op_descs; j++) { 168 if (vfs_op_offsets[j - 1] < k && vfs_op_offsets[j] > k) 169 break; 170 k = vfs_op_offsets[j] + 1; 171 } 172 vfs_op_descs[i]->vdesc_offset = k++; 173 } 174 FREE(vfs_op_offsets, M_TEMP); 175 176 /* Panic if new vops will cause vector overflow */ 177 if (k > vfs_opv_numops) 178 panic("VFS: Ran out of vop_t vector entries. %d entries required, only %d available.\n", k, vfs_opv_numops); 179 180 /* 181 * Allocate and fill in the vectors 182 */ 183 for (i = 0; i < vnodeopv_num; i++) { 184 opv = vnodeopv_descs[i]; 185 opv_desc_vector_p = opv->opv_desc_vector_p; 186 if (*opv_desc_vector_p == NULL) 187 MALLOC(*opv_desc_vector_p, vop_t **, 188 vfs_opv_numops * sizeof(vop_t *), M_VNODE, 189 M_WAITOK | M_ZERO); 190 191 /* Fill in, with slot 0 being to return EOPNOTSUPP */ 192 opv_desc_vector = *opv_desc_vector_p; 193 opv_desc_vector[0] = (vop_t *)vop_eopnotsupp; 194 for (j = 0; opv->opv_desc_ops[j].opve_op; j++) { 195 opve_descp = &(opv->opv_desc_ops[j]); 196 opv_desc_vector[opve_descp->opve_op->vdesc_offset] = 197 opve_descp->opve_impl; 198 } 199 200 /* Replace unfilled routines with their default (slot 1). */ 201 opv_desc_vector = *(opv->opv_desc_vector_p); 202 if (opv_desc_vector[1] == NULL) 203 panic("vfs_opv_recalc: vector without a default."); 204 for (j = 0; j < vfs_opv_numops; j++) 205 if (opv_desc_vector[j] == NULL) 206 opv_desc_vector[j] = opv_desc_vector[1]; 207 } 208 } 209 210 /* Add a set of vnode operations (a description) to the table above. */ 211 void 212 vfs_add_vnodeops(const void *data) 213 { 214 const struct vnodeopv_desc *opv; 215 const struct vnodeopv_desc **newopv; 216 struct vnodeop_desc **newop; 217 int *newref; 218 vop_t **opv_desc_vector; 219 struct vnodeop_desc *desc; 220 int i, j; 221 222 opv = (const struct vnodeopv_desc *)data; 223 MALLOC(newopv, const struct vnodeopv_desc **, 224 (vnodeopv_num + 1) * sizeof(*newopv), M_VNODE, M_WAITOK); 225 if (vnodeopv_descs) { 226 bcopy(vnodeopv_descs, newopv, vnodeopv_num * sizeof(*newopv)); 227 FREE(vnodeopv_descs, M_VNODE); 228 } 229 newopv[vnodeopv_num] = opv; 230 vnodeopv_descs = newopv; 231 vnodeopv_num++; 232 233 /* See if we have turned up a new vnode op desc */ 234 opv_desc_vector = *(opv->opv_desc_vector_p); 235 for (i = 0; (desc = opv->opv_desc_ops[i].opve_op); i++) { 236 for (j = 0; j < num_op_descs; j++) { 237 if (desc == vfs_op_descs[j]) { 238 /* found it, increase reference count */ 239 vfs_op_desc_refs[j]++; 240 break; 241 } 242 } 243 if (j == num_op_descs) { 244 /* not found, new entry */ 245 MALLOC(newop, struct vnodeop_desc **, 246 (num_op_descs + 1) * sizeof(*newop), 247 M_VNODE, M_WAITOK); 248 /* new reference count (for unload) */ 249 MALLOC(newref, int *, 250 (num_op_descs + 1) * sizeof(*newref), 251 M_VNODE, M_WAITOK); 252 if (vfs_op_descs) { 253 bcopy(vfs_op_descs, newop, 254 num_op_descs * sizeof(*newop)); 255 FREE(vfs_op_descs, M_VNODE); 256 } 257 if (vfs_op_desc_refs) { 258 bcopy(vfs_op_desc_refs, newref, 259 num_op_descs * sizeof(*newref)); 260 FREE(vfs_op_desc_refs, M_VNODE); 261 } 262 newop[num_op_descs] = desc; 263 newref[num_op_descs] = 1; 264 vfs_op_descs = newop; 265 vfs_op_desc_refs = newref; 266 num_op_descs++; 267 } 268 } 269 vfs_opv_recalc(); 270 } 271 272 /* Remove a vnode type from the vnode description table above. */ 273 void 274 vfs_rm_vnodeops(const void *data) 275 { 276 const struct vnodeopv_desc *opv; 277 const struct vnodeopv_desc **newopv; 278 struct vnodeop_desc **newop; 279 int *newref; 280 vop_t **opv_desc_vector; 281 struct vnodeop_desc *desc; 282 int i, j, k; 283 284 opv = (const struct vnodeopv_desc *)data; 285 /* Lower ref counts on descs in the table and release if zero */ 286 for (i = 0; (desc = opv->opv_desc_ops[i].opve_op); i++) { 287 for (j = 0; j < num_op_descs; j++) { 288 if (desc == vfs_op_descs[j]) { 289 /* found it, decrease reference count */ 290 vfs_op_desc_refs[j]--; 291 break; 292 } 293 } 294 for (j = 0; j < num_op_descs; j++) { 295 if (vfs_op_desc_refs[j] > 0) 296 continue; 297 if (vfs_op_desc_refs[j] < 0) 298 panic("vfs_remove_vnodeops: negative refcnt"); 299 /* Entry is going away - replace it with defaultop */ 300 for (k = 0; k < vnodeopv_num; k++) { 301 opv_desc_vector = 302 *(vnodeopv_descs[k]->opv_desc_vector_p); 303 if (opv_desc_vector != NULL) 304 opv_desc_vector[desc->vdesc_offset] = 305 opv_desc_vector[1]; 306 } 307 MALLOC(newop, struct vnodeop_desc **, 308 (num_op_descs - 1) * sizeof(*newop), 309 M_VNODE, M_WAITOK); 310 /* new reference count (for unload) */ 311 MALLOC(newref, int *, 312 (num_op_descs - 1) * sizeof(*newref), 313 M_VNODE, M_WAITOK); 314 for (k = j; k < (num_op_descs - 1); k++) { 315 vfs_op_descs[k] = vfs_op_descs[k + 1]; 316 vfs_op_desc_refs[k] = vfs_op_desc_refs[k + 1]; 317 } 318 bcopy(vfs_op_descs, newop, 319 (num_op_descs - 1) * sizeof(*newop)); 320 bcopy(vfs_op_desc_refs, newref, 321 (num_op_descs - 1) * sizeof(*newref)); 322 FREE(vfs_op_descs, M_VNODE); 323 FREE(vfs_op_desc_refs, M_VNODE); 324 vfs_op_descs = newop; 325 vfs_op_desc_refs = newref; 326 num_op_descs--; 327 } 328 } 329 330 for (i = 0; i < vnodeopv_num; i++) { 331 if (vnodeopv_descs[i] == opv) { 332 for (j = i; j < (vnodeopv_num - 1); j++) 333 vnodeopv_descs[j] = vnodeopv_descs[j + 1]; 334 break; 335 } 336 } 337 if (i == vnodeopv_num) 338 panic("vfs_remove_vnodeops: opv not found"); 339 opv_desc_vector = *(opv->opv_desc_vector_p); 340 if (opv_desc_vector != NULL) 341 FREE(opv_desc_vector, M_VNODE); 342 MALLOC(newopv, const struct vnodeopv_desc **, 343 (vnodeopv_num - 1) * sizeof(*newopv), M_VNODE, M_WAITOK); 344 bcopy(vnodeopv_descs, newopv, (vnodeopv_num - 1) * sizeof(*newopv)); 345 FREE(vnodeopv_descs, M_VNODE); 346 vnodeopv_descs = newopv; 347 vnodeopv_num--; 348 349 vfs_opv_recalc(); 350 } 351 352 /* 353 * Routines having to do with the management of the vnode table. 354 */ 355 struct vattr va_null; 356 357 /* 358 * Initialize the vnode structures and initialize each filesystem type. 359 */ 360 /* ARGSUSED*/ 361 static void 362 vfsinit(void *dummy) 363 { 364 365 vattr_null(&va_null); 366 } 367 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vfsinit, NULL) 368 369 /* Register a new filesystem type in the global table */ 370 int 371 vfs_register(struct vfsconf *vfc) 372 { 373 struct sysctl_oid *oidp; 374 struct vfsconf *vfsp; 375 376 vfsp = NULL; 377 if (vfsconf) 378 for (vfsp = vfsconf; vfsp->vfc_next; vfsp = vfsp->vfc_next) 379 if (strcmp(vfc->vfc_name, vfsp->vfc_name) == 0) 380 return EEXIST; 381 382 vfc->vfc_typenum = maxvfsconf++; 383 if (vfsp) 384 vfsp->vfc_next = vfc; 385 else 386 vfsconf = vfc; 387 vfc->vfc_next = NULL; 388 389 /* 390 * If this filesystem has a sysctl node under vfs 391 * (i.e. vfs.xxfs), then change the oid number of that node to 392 * match the filesystem's type number. This allows user code 393 * which uses the type number to read sysctl variables defined 394 * by the filesystem to continue working. Since the oids are 395 * in a sorted list, we need to make sure the order is 396 * preserved by re-registering the oid after modifying its 397 * number. 398 */ 399 SLIST_FOREACH(oidp, &sysctl__vfs_children, oid_link) 400 if (strcmp(oidp->oid_name, vfc->vfc_name) == 0) { 401 sysctl_unregister_oid(oidp); 402 oidp->oid_number = vfc->vfc_typenum; 403 sysctl_register_oid(oidp); 404 } 405 406 /* 407 * Call init function for this VFS... 408 */ 409 (*(vfc->vfc_vfsops->vfs_init))(vfc); 410 411 return 0; 412 } 413 414 415 /* Remove registration of a filesystem type */ 416 int 417 vfs_unregister(struct vfsconf *vfc) 418 { 419 struct vfsconf *vfsp, *prev_vfsp; 420 int error, i, maxtypenum; 421 422 i = vfc->vfc_typenum; 423 424 prev_vfsp = NULL; 425 for (vfsp = vfsconf; vfsp; 426 prev_vfsp = vfsp, vfsp = vfsp->vfc_next) { 427 if (!strcmp(vfc->vfc_name, vfsp->vfc_name)) 428 break; 429 } 430 if (vfsp == NULL) 431 return EINVAL; 432 if (vfsp->vfc_refcount) 433 return EBUSY; 434 if (vfc->vfc_vfsops->vfs_uninit != NULL) { 435 error = (*vfc->vfc_vfsops->vfs_uninit)(vfsp); 436 if (error) 437 return (error); 438 } 439 if (prev_vfsp) 440 prev_vfsp->vfc_next = vfsp->vfc_next; 441 else 442 vfsconf = vfsp->vfc_next; 443 maxtypenum = VFS_GENERIC; 444 for (vfsp = vfsconf; vfsp != NULL; vfsp = vfsp->vfc_next) 445 if (maxtypenum < vfsp->vfc_typenum) 446 maxtypenum = vfsp->vfc_typenum; 447 maxvfsconf = maxtypenum + 1; 448 return 0; 449 } 450 451 /* 452 * Standard kernel module handling code for filesystem modules. 453 * Referenced from VFS_SET(). 454 */ 455 int 456 vfs_modevent(module_t mod, int type, void *data) 457 { 458 struct vfsconf *vfc; 459 int error = 0; 460 461 vfc = (struct vfsconf *)data; 462 463 switch (type) { 464 case MOD_LOAD: 465 if (vfc) 466 error = vfs_register(vfc); 467 break; 468 469 case MOD_UNLOAD: 470 if (vfc) 471 error = vfs_unregister(vfc); 472 break; 473 default: /* including MOD_SHUTDOWN */ 474 break; 475 } 476 return (error); 477 } 478