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/lock.h> 51 #include <sys/malloc.h> 52 #include <sys/mount.h> 53 #include <sys/namei.h> 54 #include <sys/proc.h> 55 #include <sys/vnode.h> 56 57 #include <fs/nullfs/null.h> 58 59 static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure"); 60 61 static int nullfs_fhtovp(struct mount *mp, struct fid *fidp, 62 struct vnode **vpp); 63 static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam, 64 int *extflagsp, struct ucred **credanonp); 65 static int nullfs_mount(struct mount *mp, struct nameidata *ndp, 66 struct thread *td); 67 static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, 68 caddr_t arg, struct thread *td); 69 static int nullfs_root(struct mount *mp, struct vnode **vpp); 70 static int nullfs_start(struct mount *mp, int flags, struct thread *td); 71 static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 72 struct thread *td); 73 static int nullfs_sync(struct mount *mp, int waitfor, 74 struct ucred *cred, struct thread *td); 75 static int nullfs_unmount(struct mount *mp, int mntflags, struct thread *td); 76 static int nullfs_vget(struct mount *mp, ino_t ino, int flags, 77 struct vnode **vpp); 78 static int nullfs_vptofh(struct vnode *vp, struct fid *fhp); 79 static int nullfs_extattrctl(struct mount *mp, int cmd, 80 struct vnode *filename_vp, 81 int namespace, const char *attrname, 82 struct thread *td); 83 84 /* 85 * Mount null layer 86 */ 87 static int 88 nullfs_mount(mp, ndp, td) 89 struct mount *mp; 90 struct nameidata *ndp; 91 struct thread *td; 92 { 93 int error = 0; 94 struct vnode *lowerrootvp, *vp; 95 struct vnode *nullm_rootvp; 96 struct null_mount *xmp; 97 char *target; 98 size_t size; 99 int isvnunlocked = 0, len; 100 101 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 102 103 /* 104 * Update is a no-op 105 */ 106 if (mp->mnt_flag & MNT_UPDATE) { 107 return (EOPNOTSUPP); 108 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, td);*/ 109 } 110 111 /* 112 * Get argument 113 */ 114 error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len); 115 if (error || target[len - 1] != '\0') 116 return (EINVAL); 117 118 /* 119 * Unlock lower node to avoid deadlock. 120 * (XXX) VOP_ISLOCKED is needed? 121 */ 122 if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) && 123 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 124 VOP_UNLOCK(mp->mnt_vnodecovered, 0, td); 125 isvnunlocked = 1; 126 } 127 /* 128 * Find lower node 129 */ 130 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 131 UIO_SYSSPACE, target, td); 132 error = namei(ndp); 133 /* 134 * Re-lock vnode. 135 */ 136 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 137 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td); 138 139 if (error) 140 return (error); 141 NDFREE(ndp, NDF_ONLY_PNBUF); 142 143 /* 144 * Sanity check on lower vnode 145 */ 146 lowerrootvp = ndp->ni_vp; 147 148 vrele(ndp->ni_dvp); 149 ndp->ni_dvp = NULLVP; 150 151 /* 152 * Check multi null mount to avoid `lock against myself' panic. 153 */ 154 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 155 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 156 vput(lowerrootvp); 157 return (EDEADLK); 158 } 159 160 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 161 M_NULLFSMNT, M_WAITOK); /* XXX */ 162 163 /* 164 * Save reference to underlying FS 165 */ 166 xmp->nullm_vfs = lowerrootvp->v_mount; 167 168 /* 169 * Save reference. Each mount also holds 170 * a reference on the root vnode. 171 */ 172 error = null_nodeget(mp, lowerrootvp, &vp); 173 /* 174 * Unlock the node (either the lower or the alias) 175 */ 176 VOP_UNLOCK(vp, 0, td); 177 /* 178 * Make sure the node alias worked 179 */ 180 if (error) { 181 vrele(lowerrootvp); 182 free(xmp, M_NULLFSMNT); /* XXX */ 183 return (error); 184 } 185 186 /* 187 * Keep a held reference to the root vnode. 188 * It is vrele'd in nullfs_unmount. 189 */ 190 nullm_rootvp = vp; 191 nullm_rootvp->v_flag |= VROOT; 192 xmp->nullm_rootvp = nullm_rootvp; 193 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 194 mp->mnt_flag |= MNT_LOCAL; 195 mp->mnt_data = (qaddr_t) xmp; 196 vfs_getnewfsid(mp); 197 198 (void) copystr(target, mp->mnt_stat.f_mntfromname, 199 MNAMELEN - 1, &size); 200 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 201 (void)nullfs_statfs(mp, &mp->mnt_stat, td); 202 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 203 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 204 return (0); 205 } 206 207 /* 208 * VFS start. Nothing needed here - the start routine 209 * on the underlying filesystem will have been called 210 * when that filesystem was mounted. 211 */ 212 static int 213 nullfs_start(mp, flags, td) 214 struct mount *mp; 215 int flags; 216 struct thread *td; 217 { 218 return (0); 219 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */ 220 } 221 222 /* 223 * Free reference to null layer 224 */ 225 static int 226 nullfs_unmount(mp, mntflags, td) 227 struct mount *mp; 228 int mntflags; 229 struct thread *td; 230 { 231 void *mntdata; 232 int error; 233 int flags = 0; 234 235 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 236 237 if (mntflags & MNT_FORCE) 238 flags |= FORCECLOSE; 239 240 /* There is 1 extra root vnode reference (nullm_rootvp). */ 241 error = vflush(mp, 1, flags); 242 if (error) 243 return (error); 244 245 /* 246 * Finally, throw away the null_mount structure 247 */ 248 mntdata = mp->mnt_data; 249 mp->mnt_data = 0; 250 free(mntdata, M_NULLFSMNT); 251 return 0; 252 } 253 254 static int 255 nullfs_root(mp, vpp) 256 struct mount *mp; 257 struct vnode **vpp; 258 { 259 struct thread *td = curthread; /* XXX */ 260 struct vnode *vp; 261 262 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 263 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 264 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 265 266 /* 267 * Return locked reference to root. 268 */ 269 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 270 VREF(vp); 271 272 #ifdef NULLFS_DEBUG 273 if (VOP_ISLOCKED(vp, NULL)) { 274 Debugger("root vnode is locked.\n"); 275 vrele(vp); 276 return (EDEADLK); 277 } 278 #endif 279 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 280 *vpp = vp; 281 return 0; 282 } 283 284 static int 285 nullfs_quotactl(mp, cmd, uid, arg, td) 286 struct mount *mp; 287 int cmd; 288 uid_t uid; 289 caddr_t arg; 290 struct thread *td; 291 { 292 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); 293 } 294 295 static int 296 nullfs_statfs(mp, sbp, td) 297 struct mount *mp; 298 struct statfs *sbp; 299 struct thread *td; 300 { 301 int error; 302 struct statfs mstat; 303 304 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 305 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 306 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 307 308 bzero(&mstat, sizeof(mstat)); 309 310 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); 311 if (error) 312 return (error); 313 314 /* now copy across the "interesting" information and fake the rest */ 315 sbp->f_type = mstat.f_type; 316 sbp->f_flags = mstat.f_flags; 317 sbp->f_bsize = mstat.f_bsize; 318 sbp->f_iosize = mstat.f_iosize; 319 sbp->f_blocks = mstat.f_blocks; 320 sbp->f_bfree = mstat.f_bfree; 321 sbp->f_bavail = mstat.f_bavail; 322 sbp->f_files = mstat.f_files; 323 sbp->f_ffree = mstat.f_ffree; 324 if (sbp != &mp->mnt_stat) { 325 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 326 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 327 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 328 } 329 return (0); 330 } 331 332 static int 333 nullfs_sync(mp, waitfor, cred, td) 334 struct mount *mp; 335 int waitfor; 336 struct ucred *cred; 337 struct thread *td; 338 { 339 /* 340 * XXX - Assumes no data cached at null layer. 341 */ 342 return (0); 343 } 344 345 static int 346 nullfs_vget(mp, ino, flags, vpp) 347 struct mount *mp; 348 ino_t ino; 349 int flags; 350 struct vnode **vpp; 351 { 352 int error; 353 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp); 354 if (error) 355 return (error); 356 357 return (null_nodeget(mp, *vpp, vpp)); 358 } 359 360 static int 361 nullfs_fhtovp(mp, fidp, vpp) 362 struct mount *mp; 363 struct fid *fidp; 364 struct vnode **vpp; 365 { 366 int error; 367 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 368 if (error) 369 return (error); 370 371 return (null_nodeget(mp, *vpp, vpp)); 372 } 373 374 static int 375 nullfs_checkexp(mp, nam, extflagsp, credanonp) 376 struct mount *mp; 377 struct sockaddr *nam; 378 int *extflagsp; 379 struct ucred **credanonp; 380 { 381 382 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 383 extflagsp, credanonp); 384 } 385 386 static int 387 nullfs_vptofh(vp, fhp) 388 struct vnode *vp; 389 struct fid *fhp; 390 { 391 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 392 } 393 394 static int 395 nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname, td) 396 struct mount *mp; 397 int cmd; 398 struct vnode *filename_vp; 399 int namespace; 400 const char *attrname; 401 struct thread *td; 402 { 403 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp, 404 namespace, attrname, td); 405 } 406 407 408 static struct vfsops null_vfsops = { 409 NULL, 410 nullfs_start, 411 nullfs_unmount, 412 nullfs_root, 413 nullfs_quotactl, 414 nullfs_statfs, 415 nullfs_sync, 416 nullfs_vget, 417 nullfs_fhtovp, 418 nullfs_checkexp, 419 nullfs_vptofh, 420 nullfs_init, 421 nullfs_uninit, 422 nullfs_extattrctl, 423 nullfs_mount, 424 }; 425 426 VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK); 427