1 /* 2 * Copyright (c) 1992, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software donated to Berkeley by 6 * Jan-Simon Pendry. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94 37 * 38 * @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92 39 * $FreeBSD$ 40 */ 41 42 /* 43 * Null Layer 44 * (See null_vnops.c for a description of what this does.) 45 */ 46 47 #include <sys/param.h> 48 #include <sys/systm.h> 49 #include <sys/kernel.h> 50 #include <sys/malloc.h> 51 #include <sys/vnode.h> 52 #include <sys/mount.h> 53 #include <sys/namei.h> 54 #include <miscfs/nullfs/null.h> 55 56 static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure"); 57 58 static int nullfs_fhtovp(struct mount *mp, struct fid *fidp, 59 struct vnode **vpp); 60 static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam, 61 int *extflagsp, struct ucred **credanonp); 62 static int nullfs_mount(struct mount *mp, char *path, caddr_t data, 63 struct nameidata *ndp, struct proc *p); 64 static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, 65 caddr_t arg, struct proc *p); 66 static int nullfs_root(struct mount *mp, struct vnode **vpp); 67 static int nullfs_start(struct mount *mp, int flags, struct proc *p); 68 static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 69 struct proc *p); 70 static int nullfs_sync(struct mount *mp, int waitfor, 71 struct ucred *cred, struct proc *p); 72 static int nullfs_unmount(struct mount *mp, int mntflags, struct proc *p); 73 static int nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp); 74 static int nullfs_vptofh(struct vnode *vp, struct fid *fhp); 75 static int nullfs_extattrctl(struct mount *mp, int cmd, 76 struct vnode *filename_vp, 77 int namespace, const char *attrname, 78 struct proc *p); 79 80 /* 81 * Mount null layer 82 */ 83 static int 84 nullfs_mount(mp, path, data, ndp, p) 85 struct mount *mp; 86 char *path; 87 caddr_t data; 88 struct nameidata *ndp; 89 struct proc *p; 90 { 91 int error = 0; 92 struct null_args args; 93 struct vnode *lowerrootvp, *vp; 94 struct vnode *nullm_rootvp; 95 struct null_mount *xmp; 96 u_int size; 97 int isvnunlocked = 0; 98 99 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 100 101 /* 102 * Update is a no-op 103 */ 104 if (mp->mnt_flag & MNT_UPDATE) { 105 return (EOPNOTSUPP); 106 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/ 107 } 108 109 /* 110 * Get argument 111 */ 112 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 113 if (error) 114 return (error); 115 116 /* 117 * Unlock lower node to avoid deadlock. 118 * (XXX) VOP_ISLOCKED is needed? 119 */ 120 if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) && 121 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 122 VOP_UNLOCK(mp->mnt_vnodecovered, 0, p); 123 isvnunlocked = 1; 124 } 125 /* 126 * Find lower node 127 */ 128 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 129 UIO_USERSPACE, args.target, p); 130 error = namei(ndp); 131 /* 132 * Re-lock vnode. 133 */ 134 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 135 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, p); 136 137 if (error) 138 return (error); 139 NDFREE(ndp, NDF_ONLY_PNBUF); 140 141 /* 142 * Sanity check on lower vnode 143 */ 144 lowerrootvp = ndp->ni_vp; 145 146 vrele(ndp->ni_dvp); 147 ndp->ni_dvp = NULLVP; 148 149 /* 150 * Check multi null mount to avoid `lock against myself' panic. 151 */ 152 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 153 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 154 vput(lowerrootvp); 155 return (EDEADLK); 156 } 157 158 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 159 M_NULLFSMNT, M_WAITOK); /* XXX */ 160 161 /* 162 * Save reference to underlying FS 163 */ 164 xmp->nullm_vfs = lowerrootvp->v_mount; 165 166 /* 167 * Save reference. Each mount also holds 168 * a reference on the root vnode. 169 */ 170 error = null_node_create(mp, lowerrootvp, &vp); 171 /* 172 * Unlock the node (either the lower or the alias) 173 */ 174 VOP_UNLOCK(vp, 0, p); 175 /* 176 * Make sure the node alias worked 177 */ 178 if (error) { 179 vrele(lowerrootvp); 180 free(xmp, M_NULLFSMNT); /* XXX */ 181 return (error); 182 } 183 184 /* 185 * Keep a held reference to the root vnode. 186 * It is vrele'd in nullfs_unmount. 187 */ 188 nullm_rootvp = vp; 189 nullm_rootvp->v_flag |= VROOT; 190 xmp->nullm_rootvp = nullm_rootvp; 191 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 192 mp->mnt_flag |= MNT_LOCAL; 193 mp->mnt_data = (qaddr_t) xmp; 194 vfs_getnewfsid(mp); 195 196 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 197 &size); 198 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 199 (void)nullfs_statfs(mp, &mp->mnt_stat, p); 200 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 201 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 202 return (0); 203 } 204 205 /* 206 * VFS start. Nothing needed here - the start routine 207 * on the underlying filesystem will have been called 208 * when that filesystem was mounted. 209 */ 210 static int 211 nullfs_start(mp, flags, p) 212 struct mount *mp; 213 int flags; 214 struct proc *p; 215 { 216 return (0); 217 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */ 218 } 219 220 /* 221 * Free reference to null layer 222 */ 223 static int 224 nullfs_unmount(mp, mntflags, p) 225 struct mount *mp; 226 int mntflags; 227 struct proc *p; 228 { 229 struct vnode *vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 230 void *mntdata; 231 int error; 232 int flags = 0; 233 234 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 235 236 if (mntflags & MNT_FORCE) 237 flags |= FORCECLOSE; 238 239 error = VFS_ROOT(mp, &vp); 240 if (error) 241 return (error); 242 if (vp->v_usecount > 2) { 243 NULLFSDEBUG("nullfs_unmount: rootvp is busy(%d)\n", 244 vp->v_usecount); 245 vput(vp); 246 return (EBUSY); 247 } 248 error = vflush(mp, vp, flags); 249 if (error) 250 return (error); 251 252 #ifdef NULLFS_DEBUG 253 vprint("alias root of lower", vp); 254 #endif 255 vput(vp); 256 /* 257 * Release reference on underlying root vnode 258 */ 259 vrele(vp); 260 /* 261 * And blow it away for future re-use 262 */ 263 vgone(vp); 264 /* 265 * Finally, throw away the null_mount structure 266 */ 267 mntdata = mp->mnt_data; 268 mp->mnt_data = 0; 269 free(mntdata, M_NULLFSMNT); 270 return 0; 271 } 272 273 static int 274 nullfs_root(mp, vpp) 275 struct mount *mp; 276 struct vnode **vpp; 277 { 278 struct proc *p = curproc; /* XXX */ 279 struct vnode *vp; 280 281 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 282 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 283 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 284 285 /* 286 * Return locked reference to root. 287 */ 288 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 289 VREF(vp); 290 291 #ifdef NULLFS_DEBUG 292 if (VOP_ISLOCKED(vp, NULL)) { 293 Debugger("root vnode is locked.\n"); 294 vrele(vp); 295 return (EDEADLK); 296 } 297 #endif 298 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 299 *vpp = vp; 300 return 0; 301 } 302 303 static int 304 nullfs_quotactl(mp, cmd, uid, arg, p) 305 struct mount *mp; 306 int cmd; 307 uid_t uid; 308 caddr_t arg; 309 struct proc *p; 310 { 311 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p); 312 } 313 314 static int 315 nullfs_statfs(mp, sbp, p) 316 struct mount *mp; 317 struct statfs *sbp; 318 struct proc *p; 319 { 320 int error; 321 struct statfs mstat; 322 323 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 324 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 325 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 326 327 bzero(&mstat, sizeof(mstat)); 328 329 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p); 330 if (error) 331 return (error); 332 333 /* now copy across the "interesting" information and fake the rest */ 334 sbp->f_type = mstat.f_type; 335 sbp->f_flags = mstat.f_flags; 336 sbp->f_bsize = mstat.f_bsize; 337 sbp->f_iosize = mstat.f_iosize; 338 sbp->f_blocks = mstat.f_blocks; 339 sbp->f_bfree = mstat.f_bfree; 340 sbp->f_bavail = mstat.f_bavail; 341 sbp->f_files = mstat.f_files; 342 sbp->f_ffree = mstat.f_ffree; 343 if (sbp != &mp->mnt_stat) { 344 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 345 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 346 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 347 } 348 return (0); 349 } 350 351 static int 352 nullfs_sync(mp, waitfor, cred, p) 353 struct mount *mp; 354 int waitfor; 355 struct ucred *cred; 356 struct proc *p; 357 { 358 /* 359 * XXX - Assumes no data cached at null layer. 360 */ 361 return (0); 362 } 363 364 static int 365 nullfs_vget(mp, ino, vpp) 366 struct mount *mp; 367 ino_t ino; 368 struct vnode **vpp; 369 { 370 int error; 371 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 372 if (error) 373 return (error); 374 375 return (null_node_create(mp, *vpp, vpp)); 376 } 377 378 static int 379 nullfs_fhtovp(mp, fidp, vpp) 380 struct mount *mp; 381 struct fid *fidp; 382 struct vnode **vpp; 383 { 384 int error; 385 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 386 if (error) 387 return (error); 388 389 return (null_node_create(mp, *vpp, vpp)); 390 } 391 392 static int 393 nullfs_checkexp(mp, nam, extflagsp, credanonp) 394 struct mount *mp; 395 struct sockaddr *nam; 396 int *extflagsp; 397 struct ucred **credanonp; 398 { 399 400 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 401 extflagsp, credanonp); 402 } 403 404 static int 405 nullfs_vptofh(vp, fhp) 406 struct vnode *vp; 407 struct fid *fhp; 408 { 409 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 410 } 411 412 static int 413 nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname, p) 414 struct mount *mp; 415 int cmd; 416 struct vnode *filename_vp; 417 int namespace; 418 const char *attrname; 419 struct proc *p; 420 { 421 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp, 422 namespace, attrname, p); 423 } 424 425 426 static struct vfsops null_vfsops = { 427 nullfs_mount, 428 nullfs_start, 429 nullfs_unmount, 430 nullfs_root, 431 nullfs_quotactl, 432 nullfs_statfs, 433 nullfs_sync, 434 nullfs_vget, 435 nullfs_fhtovp, 436 nullfs_checkexp, 437 nullfs_vptofh, 438 nullfs_init, 439 nullfs_uninit, 440 nullfs_extattrctl, 441 }; 442 443 VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK); 444