| 1 | /* $NetBSD: union_vfsops.c,v 1.75 2015/07/23 09:45:21 hannken Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * Copyright (c) 1994 The Regents of the University of California. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software donated to Berkeley by |
| 8 | * Jan-Simon Pendry. |
| 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. Neither the name of the University nor the names of its contributors |
| 19 | * may be used to endorse or promote products derived from this software |
| 20 | * without specific prior written permission. |
| 21 | * |
| 22 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 23 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 24 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 25 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 26 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 27 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 28 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 29 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 30 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 31 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 32 | * SUCH DAMAGE. |
| 33 | * |
| 34 | * @(#)union_vfsops.c 8.20 (Berkeley) 5/20/95 |
| 35 | */ |
| 36 | |
| 37 | /* |
| 38 | * Copyright (c) 1994 Jan-Simon Pendry. |
| 39 | * All rights reserved. |
| 40 | * |
| 41 | * This code is derived from software donated to Berkeley by |
| 42 | * Jan-Simon Pendry. |
| 43 | * |
| 44 | * Redistribution and use in source and binary forms, with or without |
| 45 | * modification, are permitted provided that the following conditions |
| 46 | * are met: |
| 47 | * 1. Redistributions of source code must retain the above copyright |
| 48 | * notice, this list of conditions and the following disclaimer. |
| 49 | * 2. Redistributions in binary form must reproduce the above copyright |
| 50 | * notice, this list of conditions and the following disclaimer in the |
| 51 | * documentation and/or other materials provided with the distribution. |
| 52 | * 3. All advertising materials mentioning features or use of this software |
| 53 | * must display the following acknowledgement: |
| 54 | * This product includes software developed by the University of |
| 55 | * California, Berkeley and its contributors. |
| 56 | * 4. Neither the name of the University nor the names of its contributors |
| 57 | * may be used to endorse or promote products derived from this software |
| 58 | * without specific prior written permission. |
| 59 | * |
| 60 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 61 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 62 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 63 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 64 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 65 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 66 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 67 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 68 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 69 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 70 | * SUCH DAMAGE. |
| 71 | * |
| 72 | * @(#)union_vfsops.c 8.20 (Berkeley) 5/20/95 |
| 73 | */ |
| 74 | |
| 75 | /* |
| 76 | * Union Layer |
| 77 | */ |
| 78 | |
| 79 | #include <sys/cdefs.h> |
| 80 | __KERNEL_RCSID(0, "$NetBSD: union_vfsops.c,v 1.75 2015/07/23 09:45:21 hannken Exp $" ); |
| 81 | |
| 82 | #include <sys/param.h> |
| 83 | #include <sys/systm.h> |
| 84 | #include <sys/sysctl.h> |
| 85 | #include <sys/time.h> |
| 86 | #include <sys/proc.h> |
| 87 | #include <sys/vnode.h> |
| 88 | #include <sys/mount.h> |
| 89 | #include <sys/namei.h> |
| 90 | #include <sys/malloc.h> |
| 91 | #include <sys/filedesc.h> |
| 92 | #include <sys/queue.h> |
| 93 | #include <sys/stat.h> |
| 94 | #include <sys/kauth.h> |
| 95 | #include <sys/module.h> |
| 96 | |
| 97 | #include <fs/union/union.h> |
| 98 | |
| 99 | MODULE(MODULE_CLASS_VFS, union, NULL); |
| 100 | |
| 101 | static struct sysctllog *union_sysctl_log; |
| 102 | |
| 103 | /* |
| 104 | * Mount union filesystem |
| 105 | */ |
| 106 | int |
| 107 | union_mount(struct mount *mp, const char *path, void *data, size_t *data_len) |
| 108 | { |
| 109 | struct lwp *l = curlwp; |
| 110 | int error = 0; |
| 111 | struct union_args *args = data; |
| 112 | struct vnode *lowerrootvp = NULLVP; |
| 113 | struct vnode *upperrootvp = NULLVP; |
| 114 | struct union_mount *um = 0; |
| 115 | const char *cp; |
| 116 | char *xp; |
| 117 | int len; |
| 118 | size_t size; |
| 119 | |
| 120 | if (args == NULL) |
| 121 | return EINVAL; |
| 122 | if (*data_len < sizeof *args) |
| 123 | return EINVAL; |
| 124 | |
| 125 | #ifdef UNION_DIAGNOSTIC |
| 126 | printf("union_mount(mp = %p)\n" , mp); |
| 127 | #endif |
| 128 | |
| 129 | if (mp->mnt_flag & MNT_GETARGS) { |
| 130 | um = MOUNTTOUNIONMOUNT(mp); |
| 131 | if (um == NULL) |
| 132 | return EIO; |
| 133 | args->target = NULL; |
| 134 | args->mntflags = um->um_op; |
| 135 | *data_len = sizeof *args; |
| 136 | return 0; |
| 137 | } |
| 138 | /* |
| 139 | * Update is a no-op |
| 140 | */ |
| 141 | if (mp->mnt_flag & MNT_UPDATE) { |
| 142 | /* |
| 143 | * Need to provide. |
| 144 | * 1. a way to convert between rdonly and rdwr mounts. |
| 145 | * 2. support for nfs exports. |
| 146 | */ |
| 147 | error = EOPNOTSUPP; |
| 148 | goto bad; |
| 149 | } |
| 150 | |
| 151 | lowerrootvp = mp->mnt_vnodecovered; |
| 152 | vref(lowerrootvp); |
| 153 | |
| 154 | /* |
| 155 | * Find upper node. |
| 156 | */ |
| 157 | error = namei_simple_user(args->target, |
| 158 | NSM_FOLLOW_NOEMULROOT, &upperrootvp); |
| 159 | if (error != 0) |
| 160 | goto bad; |
| 161 | |
| 162 | if (upperrootvp->v_type != VDIR) { |
| 163 | error = EINVAL; |
| 164 | goto bad; |
| 165 | } |
| 166 | |
| 167 | um = kmem_zalloc(sizeof(struct union_mount), KM_SLEEP); |
| 168 | |
| 169 | /* |
| 170 | * Keep a held reference to the target vnodes. |
| 171 | * They are vrele'd in union_unmount. |
| 172 | * |
| 173 | * Depending on the _BELOW flag, the filesystems are |
| 174 | * viewed in a different order. In effect, this is the |
| 175 | * same as providing a mount under option to the mount syscall. |
| 176 | */ |
| 177 | |
| 178 | um->um_op = args->mntflags & UNMNT_OPMASK; |
| 179 | switch (um->um_op) { |
| 180 | case UNMNT_ABOVE: |
| 181 | um->um_lowervp = lowerrootvp; |
| 182 | um->um_uppervp = upperrootvp; |
| 183 | break; |
| 184 | |
| 185 | case UNMNT_BELOW: |
| 186 | um->um_lowervp = upperrootvp; |
| 187 | um->um_uppervp = lowerrootvp; |
| 188 | break; |
| 189 | |
| 190 | case UNMNT_REPLACE: |
| 191 | vrele(lowerrootvp); |
| 192 | lowerrootvp = NULLVP; |
| 193 | um->um_uppervp = upperrootvp; |
| 194 | um->um_lowervp = lowerrootvp; |
| 195 | break; |
| 196 | |
| 197 | default: |
| 198 | error = EINVAL; |
| 199 | goto bad; |
| 200 | } |
| 201 | |
| 202 | mp->mnt_iflag |= IMNT_MPSAFE; |
| 203 | |
| 204 | /* |
| 205 | * Unless the mount is readonly, ensure that the top layer |
| 206 | * supports whiteout operations |
| 207 | */ |
| 208 | if ((mp->mnt_flag & MNT_RDONLY) == 0) { |
| 209 | vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY); |
| 210 | error = VOP_WHITEOUT(um->um_uppervp, |
| 211 | (struct componentname *) 0, LOOKUP); |
| 212 | VOP_UNLOCK(um->um_uppervp); |
| 213 | if (error) |
| 214 | goto bad; |
| 215 | } |
| 216 | |
| 217 | um->um_cred = l->l_cred; |
| 218 | kauth_cred_hold(um->um_cred); |
| 219 | um->um_cmode = UN_DIRMODE &~ l->l_proc->p_cwdi->cwdi_cmask; |
| 220 | |
| 221 | /* |
| 222 | * Depending on what you think the MNT_LOCAL flag might mean, |
| 223 | * you may want the && to be || on the conditional below. |
| 224 | * At the moment it has been defined that the filesystem is |
| 225 | * only local if it is all local, ie the MNT_LOCAL flag implies |
| 226 | * that the entire namespace is local. If you think the MNT_LOCAL |
| 227 | * flag implies that some of the files might be stored locally |
| 228 | * then you will want to change the conditional. |
| 229 | */ |
| 230 | if (um->um_op == UNMNT_ABOVE) { |
| 231 | if (((um->um_lowervp == NULLVP) || |
| 232 | (um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) && |
| 233 | (um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL)) |
| 234 | mp->mnt_flag |= MNT_LOCAL; |
| 235 | } |
| 236 | |
| 237 | /* |
| 238 | * Copy in the upper layer's RDONLY flag. This is for the benefit |
| 239 | * of lookup() which explicitly checks the flag, rather than asking |
| 240 | * the filesystem for its own opinion. This means, that an update |
| 241 | * mount of the underlying filesystem to go from rdonly to rdwr |
| 242 | * will leave the unioned view as read-only. |
| 243 | */ |
| 244 | mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY); |
| 245 | |
| 246 | mp->mnt_data = um; |
| 247 | vfs_getnewfsid(mp); |
| 248 | |
| 249 | error = set_statvfs_info( path, UIO_USERSPACE, NULL, UIO_USERSPACE, |
| 250 | mp->mnt_op->vfs_name, mp, l); |
| 251 | if (error) |
| 252 | goto bad; |
| 253 | |
| 254 | switch (um->um_op) { |
| 255 | case UNMNT_ABOVE: |
| 256 | cp = "<above>:" ; |
| 257 | break; |
| 258 | case UNMNT_BELOW: |
| 259 | cp = "<below>:" ; |
| 260 | break; |
| 261 | case UNMNT_REPLACE: |
| 262 | cp = "" ; |
| 263 | break; |
| 264 | default: |
| 265 | cp = "<invalid>:" ; |
| 266 | #ifdef DIAGNOSTIC |
| 267 | panic("union_mount: bad um_op" ); |
| 268 | #endif |
| 269 | break; |
| 270 | } |
| 271 | len = strlen(cp); |
| 272 | memcpy(mp->mnt_stat.f_mntfromname, cp, len); |
| 273 | |
| 274 | xp = mp->mnt_stat.f_mntfromname + len; |
| 275 | len = MNAMELEN - len; |
| 276 | |
| 277 | (void) copyinstr(args->target, xp, len - 1, &size); |
| 278 | memset(xp + size, 0, len - size); |
| 279 | |
| 280 | #ifdef UNION_DIAGNOSTIC |
| 281 | printf("union_mount: from %s, on %s\n" , |
| 282 | mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); |
| 283 | #endif |
| 284 | |
| 285 | /* Setup the readdir hook if it's not set already */ |
| 286 | if (!vn_union_readdir_hook) |
| 287 | vn_union_readdir_hook = union_readdirhook; |
| 288 | |
| 289 | return (0); |
| 290 | |
| 291 | bad: |
| 292 | if (um) |
| 293 | kmem_free(um, sizeof(struct union_mount)); |
| 294 | if (upperrootvp) |
| 295 | vrele(upperrootvp); |
| 296 | if (lowerrootvp) |
| 297 | vrele(lowerrootvp); |
| 298 | return (error); |
| 299 | } |
| 300 | |
| 301 | /* |
| 302 | * VFS start. Nothing needed here - the start routine |
| 303 | * on the underlying filesystem(s) will have been called |
| 304 | * when that filesystem was mounted. |
| 305 | */ |
| 306 | /*ARGSUSED*/ |
| 307 | int |
| 308 | union_start(struct mount *mp, int flags) |
| 309 | { |
| 310 | |
| 311 | return (0); |
| 312 | } |
| 313 | |
| 314 | /* |
| 315 | * Free reference to union layer |
| 316 | */ |
| 317 | static bool |
| 318 | union_unmount_selector(void *cl, struct vnode *vp) |
| 319 | { |
| 320 | int *count = cl; |
| 321 | |
| 322 | *count += 1; |
| 323 | return false; |
| 324 | } |
| 325 | |
| 326 | int |
| 327 | union_unmount(struct mount *mp, int mntflags) |
| 328 | { |
| 329 | struct union_mount *um = MOUNTTOUNIONMOUNT(mp); |
| 330 | int freeing; |
| 331 | int error; |
| 332 | |
| 333 | #ifdef UNION_DIAGNOSTIC |
| 334 | printf("union_unmount(mp = %p)\n" , mp); |
| 335 | #endif |
| 336 | |
| 337 | /* |
| 338 | * Keep flushing vnodes from the mount list. |
| 339 | * This is needed because of the un_pvp held |
| 340 | * reference to the parent vnode. |
| 341 | * If more vnodes have been freed on a given pass, |
| 342 | * the try again. The loop will iterate at most |
| 343 | * (d) times, where (d) is the maximum tree depth |
| 344 | * in the filesystem. |
| 345 | */ |
| 346 | for (freeing = 0; (error = vflush(mp, NULL, 0)) != 0;) { |
| 347 | struct vnode_iterator *marker; |
| 348 | int n; |
| 349 | |
| 350 | /* count #vnodes held on mount list */ |
| 351 | n = 0; |
| 352 | vfs_vnode_iterator_init(mp, &marker); |
| 353 | vfs_vnode_iterator_next(marker, union_unmount_selector, &n); |
| 354 | vfs_vnode_iterator_destroy(marker); |
| 355 | |
| 356 | /* if this is unchanged then stop */ |
| 357 | if (n == freeing) |
| 358 | break; |
| 359 | |
| 360 | /* otherwise try once more time */ |
| 361 | freeing = n; |
| 362 | } |
| 363 | |
| 364 | /* |
| 365 | * Ok, now that we've tried doing it gently, get out the hammer. |
| 366 | */ |
| 367 | |
| 368 | if (mntflags & MNT_FORCE) |
| 369 | error = vflush(mp, NULL, FORCECLOSE); |
| 370 | |
| 371 | if (error) |
| 372 | return error; |
| 373 | |
| 374 | /* |
| 375 | * Discard references to upper and lower target vnodes. |
| 376 | */ |
| 377 | if (um->um_lowervp) |
| 378 | vrele(um->um_lowervp); |
| 379 | vrele(um->um_uppervp); |
| 380 | kauth_cred_free(um->um_cred); |
| 381 | /* |
| 382 | * Finally, throw away the union_mount structure |
| 383 | */ |
| 384 | kmem_free(um, sizeof(struct union_mount)); |
| 385 | mp->mnt_data = NULL; |
| 386 | return 0; |
| 387 | } |
| 388 | |
| 389 | int |
| 390 | union_root(struct mount *mp, struct vnode **vpp) |
| 391 | { |
| 392 | struct union_mount *um = MOUNTTOUNIONMOUNT(mp); |
| 393 | int error; |
| 394 | |
| 395 | /* |
| 396 | * Return locked reference to root. |
| 397 | */ |
| 398 | vref(um->um_uppervp); |
| 399 | if (um->um_lowervp) |
| 400 | vref(um->um_lowervp); |
| 401 | error = union_allocvp(vpp, mp, NULL, NULL, NULL, |
| 402 | um->um_uppervp, um->um_lowervp, 1); |
| 403 | |
| 404 | if (error) { |
| 405 | vrele(um->um_uppervp); |
| 406 | if (um->um_lowervp) |
| 407 | vrele(um->um_lowervp); |
| 408 | return error; |
| 409 | } |
| 410 | |
| 411 | vn_lock(*vpp, LK_EXCLUSIVE | LK_RETRY); |
| 412 | |
| 413 | return 0; |
| 414 | } |
| 415 | |
| 416 | int |
| 417 | union_statvfs(struct mount *mp, struct statvfs *sbp) |
| 418 | { |
| 419 | int error; |
| 420 | struct union_mount *um = MOUNTTOUNIONMOUNT(mp); |
| 421 | struct statvfs *sbuf = malloc(sizeof(*sbuf), M_TEMP, M_WAITOK | M_ZERO); |
| 422 | unsigned long lbsize; |
| 423 | |
| 424 | #ifdef UNION_DIAGNOSTIC |
| 425 | printf("union_statvfs(mp = %p, lvp = %p, uvp = %p)\n" , mp, |
| 426 | um->um_lowervp, um->um_uppervp); |
| 427 | #endif |
| 428 | |
| 429 | if (um->um_lowervp) { |
| 430 | error = VFS_STATVFS(um->um_lowervp->v_mount, sbuf); |
| 431 | if (error) |
| 432 | goto done; |
| 433 | } |
| 434 | |
| 435 | /* now copy across the "interesting" information and fake the rest */ |
| 436 | lbsize = sbuf->f_bsize; |
| 437 | sbp->f_blocks = sbuf->f_blocks - sbuf->f_bfree; |
| 438 | sbp->f_files = sbuf->f_files - sbuf->f_ffree; |
| 439 | |
| 440 | error = VFS_STATVFS(um->um_uppervp->v_mount, sbuf); |
| 441 | if (error) |
| 442 | goto done; |
| 443 | |
| 444 | sbp->f_flag = sbuf->f_flag; |
| 445 | sbp->f_bsize = sbuf->f_bsize; |
| 446 | sbp->f_frsize = sbuf->f_frsize; |
| 447 | sbp->f_iosize = sbuf->f_iosize; |
| 448 | |
| 449 | /* |
| 450 | * The "total" fields count total resources in all layers, |
| 451 | * the "free" fields count only those resources which are |
| 452 | * free in the upper layer (since only the upper layer |
| 453 | * is writable). |
| 454 | */ |
| 455 | |
| 456 | if (sbuf->f_bsize != lbsize) |
| 457 | sbp->f_blocks = sbp->f_blocks * lbsize / sbuf->f_bsize; |
| 458 | sbp->f_blocks += sbuf->f_blocks; |
| 459 | sbp->f_bfree = sbuf->f_bfree; |
| 460 | sbp->f_bavail = sbuf->f_bavail; |
| 461 | sbp->f_bresvd = sbuf->f_bresvd; |
| 462 | sbp->f_files += sbuf->f_files; |
| 463 | sbp->f_ffree = sbuf->f_ffree; |
| 464 | sbp->f_favail = sbuf->f_favail; |
| 465 | sbp->f_fresvd = sbuf->f_fresvd; |
| 466 | |
| 467 | copy_statvfs_info(sbp, mp); |
| 468 | done: |
| 469 | free(sbuf, M_TEMP); |
| 470 | return error; |
| 471 | } |
| 472 | |
| 473 | /*ARGSUSED*/ |
| 474 | int |
| 475 | union_sync(struct mount *mp, int waitfor, |
| 476 | kauth_cred_t cred) |
| 477 | { |
| 478 | |
| 479 | /* |
| 480 | * XXX - Assumes no data cached at union layer. |
| 481 | */ |
| 482 | return (0); |
| 483 | } |
| 484 | |
| 485 | /*ARGSUSED*/ |
| 486 | int |
| 487 | union_vget(struct mount *mp, ino_t ino, |
| 488 | struct vnode **vpp) |
| 489 | { |
| 490 | |
| 491 | return (EOPNOTSUPP); |
| 492 | } |
| 493 | |
| 494 | static int |
| 495 | union_renamelock_enter(struct mount *mp) |
| 496 | { |
| 497 | struct union_mount *um = MOUNTTOUNIONMOUNT(mp); |
| 498 | |
| 499 | /* Lock just the upper fs, where the action happens. */ |
| 500 | return VFS_RENAMELOCK_ENTER(um->um_uppervp->v_mount); |
| 501 | } |
| 502 | |
| 503 | static void |
| 504 | union_renamelock_exit(struct mount *mp) |
| 505 | { |
| 506 | struct union_mount *um = MOUNTTOUNIONMOUNT(mp); |
| 507 | |
| 508 | VFS_RENAMELOCK_EXIT(um->um_uppervp->v_mount); |
| 509 | } |
| 510 | |
| 511 | extern const struct vnodeopv_desc union_vnodeop_opv_desc; |
| 512 | |
| 513 | const struct vnodeopv_desc * const union_vnodeopv_descs[] = { |
| 514 | &union_vnodeop_opv_desc, |
| 515 | NULL, |
| 516 | }; |
| 517 | |
| 518 | struct vfsops union_vfsops = { |
| 519 | .vfs_name = MOUNT_UNION, |
| 520 | .vfs_min_mount_data = sizeof (struct union_args), |
| 521 | .vfs_mount = union_mount, |
| 522 | .vfs_start = union_start, |
| 523 | .vfs_unmount = union_unmount, |
| 524 | .vfs_root = union_root, |
| 525 | .vfs_quotactl = (void *)eopnotsupp, |
| 526 | .vfs_statvfs = union_statvfs, |
| 527 | .vfs_sync = union_sync, |
| 528 | .vfs_vget = union_vget, |
| 529 | .vfs_loadvnode = union_loadvnode, |
| 530 | .vfs_fhtovp = (void *)eopnotsupp, |
| 531 | .vfs_vptofh = (void *)eopnotsupp, |
| 532 | .vfs_init = union_init, |
| 533 | .vfs_reinit = union_reinit, |
| 534 | .vfs_done = union_done, |
| 535 | .vfs_snapshot = (void *)eopnotsupp, |
| 536 | .vfs_extattrctl = vfs_stdextattrctl, |
| 537 | .vfs_suspendctl = (void *)eopnotsupp, |
| 538 | .vfs_renamelock_enter = union_renamelock_enter, |
| 539 | .vfs_renamelock_exit = union_renamelock_exit, |
| 540 | .vfs_fsync = (void *)eopnotsupp, |
| 541 | .vfs_opv_descs = union_vnodeopv_descs |
| 542 | }; |
| 543 | |
| 544 | static int |
| 545 | union_modcmd(modcmd_t cmd, void *arg) |
| 546 | { |
| 547 | int error; |
| 548 | |
| 549 | switch (cmd) { |
| 550 | case MODULE_CMD_INIT: |
| 551 | error = vfs_attach(&union_vfsops); |
| 552 | if (error != 0) |
| 553 | break; |
| 554 | sysctl_createv(&union_sysctl_log, 0, NULL, NULL, |
| 555 | CTLFLAG_PERMANENT, |
| 556 | CTLTYPE_NODE, "union" , |
| 557 | SYSCTL_DESCR("Union file system" ), |
| 558 | NULL, 0, NULL, 0, |
| 559 | CTL_VFS, 15, CTL_EOL); |
| 560 | /* |
| 561 | * XXX the "15" above could be dynamic, thereby eliminating |
| 562 | * one more instance of the "number to vfs" mapping problem, |
| 563 | * but "15" is the order as taken from sys/mount.h |
| 564 | */ |
| 565 | break; |
| 566 | case MODULE_CMD_FINI: |
| 567 | error = vfs_detach(&union_vfsops); |
| 568 | if (error != 0) |
| 569 | break; |
| 570 | sysctl_teardown(&union_sysctl_log); |
| 571 | break; |
| 572 | default: |
| 573 | error = ENOTTY; |
| 574 | break; |
| 575 | } |
| 576 | |
| 577 | return (error); |
| 578 | } |
| 579 | |