1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1994, 1995 The Regents of the University of California. 5 * Copyright (c) 1994, 1995 Jan-Simon Pendry. 6 * Copyright (c) 2005, 2006, 2012 Masanori Ozawa <ozawa@ongs.co.jp>, ONGS Inc. 7 * Copyright (c) 2006, 2012 Daichi Goto <daichi@freebsd.org> 8 * All rights reserved. 9 * 10 * This code is derived from software donated to Berkeley by 11 * Jan-Simon Pendry. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)union_vfsops.c 8.20 (Berkeley) 5/20/95 38 * $FreeBSD$ 39 */ 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/kdb.h> 44 #include <sys/fcntl.h> 45 #include <sys/kernel.h> 46 #include <sys/lock.h> 47 #include <sys/malloc.h> 48 #include <sys/mount.h> 49 #include <sys/namei.h> 50 #include <sys/proc.h> 51 #include <sys/vnode.h> 52 #include <sys/stat.h> 53 54 #include <fs/unionfs/union.h> 55 56 static MALLOC_DEFINE(M_UNIONFSMNT, "UNIONFS mount", "UNIONFS mount structure"); 57 58 static vfs_fhtovp_t unionfs_fhtovp; 59 static vfs_checkexp_t unionfs_checkexp; 60 static vfs_mount_t unionfs_domount; 61 static vfs_quotactl_t unionfs_quotactl; 62 static vfs_root_t unionfs_root; 63 static vfs_sync_t unionfs_sync; 64 static vfs_statfs_t unionfs_statfs; 65 static vfs_unmount_t unionfs_unmount; 66 static vfs_vget_t unionfs_vget; 67 static vfs_extattrctl_t unionfs_extattrctl; 68 69 static struct vfsops unionfs_vfsops; 70 71 /* 72 * Mount unionfs layer. 73 */ 74 static int 75 unionfs_domount(struct mount *mp) 76 { 77 struct mount *lowermp, *uppermp; 78 struct vnode *lowerrootvp; 79 struct vnode *upperrootvp; 80 struct unionfs_mount *ump; 81 struct thread *td; 82 char *target; 83 char *tmp; 84 char *ep; 85 struct nameidata nd, *ndp; 86 struct vattr va; 87 unionfs_copymode copymode; 88 unionfs_whitemode whitemode; 89 int below; 90 int error; 91 int len; 92 uid_t uid; 93 gid_t gid; 94 u_short udir; 95 u_short ufile; 96 97 UNIONFSDEBUG("unionfs_mount(mp = %p)\n", mp); 98 99 error = 0; 100 below = 0; 101 uid = 0; 102 gid = 0; 103 udir = 0; 104 ufile = 0; 105 copymode = UNIONFS_TRANSPARENT; /* default */ 106 whitemode = UNIONFS_WHITE_ALWAYS; 107 ndp = &nd; 108 td = curthread; 109 110 if (mp->mnt_flag & MNT_ROOTFS) { 111 vfs_mount_error(mp, "Cannot union mount root filesystem"); 112 return (EOPNOTSUPP); 113 } 114 115 /* 116 * Update is a no operation. 117 */ 118 if (mp->mnt_flag & MNT_UPDATE) { 119 vfs_mount_error(mp, "unionfs does not support mount update"); 120 return (EOPNOTSUPP); 121 } 122 123 /* 124 * Get argument 125 */ 126 error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len); 127 if (error) 128 error = vfs_getopt(mp->mnt_optnew, "from", (void **)&target, 129 &len); 130 if (error || target[len - 1] != '\0') { 131 vfs_mount_error(mp, "Invalid target"); 132 return (EINVAL); 133 } 134 if (vfs_getopt(mp->mnt_optnew, "below", NULL, NULL) == 0) 135 below = 1; 136 if (vfs_getopt(mp->mnt_optnew, "udir", (void **)&tmp, NULL) == 0) { 137 if (tmp != NULL) 138 udir = (mode_t)strtol(tmp, &ep, 8); 139 if (tmp == NULL || *ep) { 140 vfs_mount_error(mp, "Invalid udir"); 141 return (EINVAL); 142 } 143 udir &= S_IRWXU | S_IRWXG | S_IRWXO; 144 } 145 if (vfs_getopt(mp->mnt_optnew, "ufile", (void **)&tmp, NULL) == 0) { 146 if (tmp != NULL) 147 ufile = (mode_t)strtol(tmp, &ep, 8); 148 if (tmp == NULL || *ep) { 149 vfs_mount_error(mp, "Invalid ufile"); 150 return (EINVAL); 151 } 152 ufile &= S_IRWXU | S_IRWXG | S_IRWXO; 153 } 154 /* check umask, uid and gid */ 155 if (udir == 0 && ufile != 0) 156 udir = ufile; 157 if (ufile == 0 && udir != 0) 158 ufile = udir; 159 160 vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY); 161 error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred); 162 if (!error) { 163 if (udir == 0) 164 udir = va.va_mode; 165 if (ufile == 0) 166 ufile = va.va_mode; 167 uid = va.va_uid; 168 gid = va.va_gid; 169 } 170 VOP_UNLOCK(mp->mnt_vnodecovered); 171 if (error) 172 return (error); 173 174 if (mp->mnt_cred->cr_ruid == 0) { /* root only */ 175 if (vfs_getopt(mp->mnt_optnew, "uid", (void **)&tmp, 176 NULL) == 0) { 177 if (tmp != NULL) 178 uid = (uid_t)strtol(tmp, &ep, 10); 179 if (tmp == NULL || *ep) { 180 vfs_mount_error(mp, "Invalid uid"); 181 return (EINVAL); 182 } 183 } 184 if (vfs_getopt(mp->mnt_optnew, "gid", (void **)&tmp, 185 NULL) == 0) { 186 if (tmp != NULL) 187 gid = (gid_t)strtol(tmp, &ep, 10); 188 if (tmp == NULL || *ep) { 189 vfs_mount_error(mp, "Invalid gid"); 190 return (EINVAL); 191 } 192 } 193 if (vfs_getopt(mp->mnt_optnew, "copymode", (void **)&tmp, 194 NULL) == 0) { 195 if (tmp == NULL) { 196 vfs_mount_error(mp, "Invalid copymode"); 197 return (EINVAL); 198 } else if (strcasecmp(tmp, "traditional") == 0) 199 copymode = UNIONFS_TRADITIONAL; 200 else if (strcasecmp(tmp, "transparent") == 0) 201 copymode = UNIONFS_TRANSPARENT; 202 else if (strcasecmp(tmp, "masquerade") == 0) 203 copymode = UNIONFS_MASQUERADE; 204 else { 205 vfs_mount_error(mp, "Invalid copymode"); 206 return (EINVAL); 207 } 208 } 209 if (vfs_getopt(mp->mnt_optnew, "whiteout", (void **)&tmp, 210 NULL) == 0) { 211 if (tmp == NULL) { 212 vfs_mount_error(mp, "Invalid whiteout mode"); 213 return (EINVAL); 214 } else if (strcasecmp(tmp, "always") == 0) 215 whitemode = UNIONFS_WHITE_ALWAYS; 216 else if (strcasecmp(tmp, "whenneeded") == 0) 217 whitemode = UNIONFS_WHITE_WHENNEEDED; 218 else { 219 vfs_mount_error(mp, "Invalid whiteout mode"); 220 return (EINVAL); 221 } 222 } 223 } 224 /* If copymode is UNIONFS_TRADITIONAL, uid/gid is mounted user. */ 225 if (copymode == UNIONFS_TRADITIONAL) { 226 uid = mp->mnt_cred->cr_ruid; 227 gid = mp->mnt_cred->cr_rgid; 228 } 229 230 UNIONFSDEBUG("unionfs_mount: uid=%d, gid=%d\n", uid, gid); 231 UNIONFSDEBUG("unionfs_mount: udir=0%03o, ufile=0%03o\n", udir, ufile); 232 UNIONFSDEBUG("unionfs_mount: copymode=%d\n", copymode); 233 234 /* 235 * Find upper node 236 */ 237 NDINIT(ndp, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, target, td); 238 if ((error = namei(ndp))) 239 return (error); 240 241 NDFREE(ndp, NDF_ONLY_PNBUF); 242 243 /* get root vnodes */ 244 lowerrootvp = mp->mnt_vnodecovered; 245 upperrootvp = ndp->ni_vp; 246 247 /* create unionfs_mount */ 248 ump = malloc(sizeof(struct unionfs_mount), M_UNIONFSMNT, 249 M_WAITOK | M_ZERO); 250 251 /* 252 * Save reference 253 */ 254 if (below) { 255 VOP_UNLOCK(upperrootvp); 256 vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY); 257 ump->um_lowervp = upperrootvp; 258 ump->um_uppervp = lowerrootvp; 259 } else { 260 ump->um_lowervp = lowerrootvp; 261 ump->um_uppervp = upperrootvp; 262 } 263 ump->um_rootvp = NULLVP; 264 ump->um_uid = uid; 265 ump->um_gid = gid; 266 ump->um_udir = udir; 267 ump->um_ufile = ufile; 268 ump->um_copymode = copymode; 269 ump->um_whitemode = whitemode; 270 271 mp->mnt_data = ump; 272 273 /* 274 * Copy upper layer's RDONLY flag. 275 */ 276 mp->mnt_flag |= ump->um_uppervp->v_mount->mnt_flag & MNT_RDONLY; 277 278 /* 279 * Unlock the node 280 */ 281 VOP_UNLOCK(ump->um_uppervp); 282 283 /* 284 * Get the unionfs root vnode. 285 */ 286 error = unionfs_nodeget(mp, ump->um_uppervp, ump->um_lowervp, 287 NULLVP, &(ump->um_rootvp), NULL, td); 288 vrele(upperrootvp); 289 if (error != 0) { 290 free(ump, M_UNIONFSMNT); 291 mp->mnt_data = NULL; 292 return (error); 293 } 294 295 lowermp = vfs_register_upper_from_vp(ump->um_lowervp, mp, 296 &ump->um_lower_link); 297 uppermp = vfs_register_upper_from_vp(ump->um_uppervp, mp, 298 &ump->um_upper_link); 299 300 if (lowermp == NULL || uppermp == NULL) { 301 if (lowermp != NULL) 302 vfs_unregister_upper(lowermp, &ump->um_lower_link); 303 if (uppermp != NULL) 304 vfs_unregister_upper(uppermp, &ump->um_upper_link); 305 free(ump, M_UNIONFSMNT); 306 mp->mnt_data = NULL; 307 return (ENOENT); 308 } 309 310 MNT_ILOCK(mp); 311 if ((lowermp->mnt_flag & MNT_LOCAL) != 0 && 312 (uppermp->mnt_flag & MNT_LOCAL) != 0) 313 mp->mnt_flag |= MNT_LOCAL; 314 mp->mnt_kern_flag |= MNTK_NOMSYNC | MNTK_UNIONFS; 315 MNT_IUNLOCK(mp); 316 317 /* 318 * Get new fsid 319 */ 320 vfs_getnewfsid(mp); 321 322 snprintf(mp->mnt_stat.f_mntfromname, MNAMELEN, "<%s>:%s", 323 below ? "below" : "above", target); 324 325 UNIONFSDEBUG("unionfs_mount: from %s, on %s\n", 326 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 327 328 return (0); 329 } 330 331 /* 332 * Free reference to unionfs layer 333 */ 334 static int 335 unionfs_unmount(struct mount *mp, int mntflags) 336 { 337 struct unionfs_mount *ump; 338 int error; 339 int num; 340 int freeing; 341 int flags; 342 343 UNIONFSDEBUG("unionfs_unmount: mp = %p\n", mp); 344 345 ump = MOUNTTOUNIONFSMOUNT(mp); 346 flags = 0; 347 348 if (mntflags & MNT_FORCE) 349 flags |= FORCECLOSE; 350 351 /* vflush (no need to call vrele) */ 352 for (freeing = 0; (error = vflush(mp, 1, flags, curthread)) != 0;) { 353 num = mp->mnt_nvnodelistsize; 354 if (num == freeing) 355 break; 356 freeing = num; 357 } 358 359 if (error) 360 return (error); 361 362 vfs_unregister_upper(ump->um_lowervp->v_mount, &ump->um_lower_link); 363 vfs_unregister_upper(ump->um_uppervp->v_mount, &ump->um_upper_link); 364 free(ump, M_UNIONFSMNT); 365 mp->mnt_data = NULL; 366 367 return (0); 368 } 369 370 static int 371 unionfs_root(struct mount *mp, int flags, struct vnode **vpp) 372 { 373 struct unionfs_mount *ump; 374 struct vnode *vp; 375 376 ump = MOUNTTOUNIONFSMOUNT(mp); 377 vp = ump->um_rootvp; 378 379 UNIONFSDEBUG("unionfs_root: rootvp=%p locked=%x\n", 380 vp, VOP_ISLOCKED(vp)); 381 382 vref(vp); 383 if (flags & LK_TYPE_MASK) 384 vn_lock(vp, flags); 385 386 *vpp = vp; 387 388 return (0); 389 } 390 391 static int 392 unionfs_quotactl(struct mount *mp, int cmd, uid_t uid, void *arg, 393 bool *mp_busy) 394 { 395 struct mount *uppermp; 396 struct unionfs_mount *ump; 397 int error; 398 bool unbusy; 399 400 ump = MOUNTTOUNIONFSMOUNT(mp); 401 uppermp = atomic_load_ptr(&ump->um_uppervp->v_mount); 402 KASSERT(*mp_busy == true, ("upper mount not busy")); 403 /* 404 * See comment in sys_quotactl() for an explanation of why the 405 * lower mount needs to be busied by the caller of VFS_QUOTACTL() 406 * but may be unbusied by the implementation. We must unbusy 407 * the upper mount for the same reason; otherwise a namei lookup 408 * issued by the VFS_QUOTACTL() implementation could traverse the 409 * upper mount and deadlock. 410 */ 411 vfs_unbusy(mp); 412 *mp_busy = false; 413 unbusy = true; 414 error = vfs_busy(uppermp, 0); 415 /* 416 * Writing is always performed to upper vnode. 417 */ 418 if (error == 0) 419 error = VFS_QUOTACTL(uppermp, cmd, uid, arg, &unbusy); 420 if (unbusy) 421 vfs_unbusy(uppermp); 422 423 return (error); 424 } 425 426 static int 427 unionfs_statfs(struct mount *mp, struct statfs *sbp) 428 { 429 struct unionfs_mount *ump; 430 struct statfs *mstat; 431 uint64_t lbsize; 432 int error; 433 434 ump = MOUNTTOUNIONFSMOUNT(mp); 435 436 UNIONFSDEBUG("unionfs_statfs(mp = %p, lvp = %p, uvp = %p)\n", 437 mp, ump->um_lowervp, ump->um_uppervp); 438 439 mstat = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK | M_ZERO); 440 441 error = VFS_STATFS(ump->um_lowervp->v_mount, mstat); 442 if (error) { 443 free(mstat, M_STATFS); 444 return (error); 445 } 446 447 /* now copy across the "interesting" information and fake the rest */ 448 sbp->f_blocks = mstat->f_blocks; 449 sbp->f_files = mstat->f_files; 450 451 lbsize = mstat->f_bsize; 452 453 error = VFS_STATFS(ump->um_uppervp->v_mount, mstat); 454 if (error) { 455 free(mstat, M_STATFS); 456 return (error); 457 } 458 459 /* 460 * The FS type etc is copy from upper vfs. 461 * (write able vfs have priority) 462 */ 463 sbp->f_type = mstat->f_type; 464 sbp->f_flags = mstat->f_flags; 465 sbp->f_bsize = mstat->f_bsize; 466 sbp->f_iosize = mstat->f_iosize; 467 468 if (mstat->f_bsize != lbsize) 469 sbp->f_blocks = ((off_t)sbp->f_blocks * lbsize) / 470 mstat->f_bsize; 471 472 sbp->f_blocks += mstat->f_blocks; 473 sbp->f_bfree = mstat->f_bfree; 474 sbp->f_bavail = mstat->f_bavail; 475 sbp->f_files += mstat->f_files; 476 sbp->f_ffree = mstat->f_ffree; 477 478 free(mstat, M_STATFS); 479 return (0); 480 } 481 482 static int 483 unionfs_sync(struct mount *mp, int waitfor) 484 { 485 /* nothing to do */ 486 return (0); 487 } 488 489 static int 490 unionfs_vget(struct mount *mp, ino_t ino, int flags, struct vnode **vpp) 491 { 492 return (EOPNOTSUPP); 493 } 494 495 static int 496 unionfs_fhtovp(struct mount *mp, struct fid *fidp, int flags, 497 struct vnode **vpp) 498 { 499 return (EOPNOTSUPP); 500 } 501 502 static int 503 unionfs_checkexp(struct mount *mp, struct sockaddr *nam, uint64_t *extflagsp, 504 struct ucred **credanonp, int *numsecflavors, int *secflavors) 505 { 506 return (EOPNOTSUPP); 507 } 508 509 static int 510 unionfs_extattrctl(struct mount *mp, int cmd, struct vnode *filename_vp, 511 int namespace, const char *attrname) 512 { 513 struct unionfs_mount *ump; 514 struct unionfs_node *unp; 515 516 ump = MOUNTTOUNIONFSMOUNT(mp); 517 unp = VTOUNIONFS(filename_vp); 518 519 if (unp->un_uppervp != NULLVP) { 520 return (VFS_EXTATTRCTL(ump->um_uppervp->v_mount, cmd, 521 unp->un_uppervp, namespace, attrname)); 522 } else { 523 return (VFS_EXTATTRCTL(ump->um_lowervp->v_mount, cmd, 524 unp->un_lowervp, namespace, attrname)); 525 } 526 } 527 528 static struct vfsops unionfs_vfsops = { 529 .vfs_checkexp = unionfs_checkexp, 530 .vfs_extattrctl = unionfs_extattrctl, 531 .vfs_fhtovp = unionfs_fhtovp, 532 .vfs_init = unionfs_init, 533 .vfs_mount = unionfs_domount, 534 .vfs_quotactl = unionfs_quotactl, 535 .vfs_root = unionfs_root, 536 .vfs_statfs = unionfs_statfs, 537 .vfs_sync = unionfs_sync, 538 .vfs_uninit = unionfs_uninit, 539 .vfs_unmount = unionfs_unmount, 540 .vfs_vget = unionfs_vget, 541 }; 542 543 VFS_SET(unionfs_vfsops, unionfs, VFCF_LOOPBACK); 544