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: src/sys/miscfs/nullfs/null_vfsops.c,v 1.35.2.3 2001/07/26 20:37:11 iedowse Exp $ 40 * $DragonFly: src/sys/vfs/nullfs/null_vfsops.c,v 1.2 2003/06/17 04:28:42 dillon Exp $ 41 */ 42 43 /* 44 * Null Layer 45 * (See null_vnops.c for a description of what this does.) 46 */ 47 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/kernel.h> 51 #include <sys/proc.h> 52 #include <sys/malloc.h> 53 #include <sys/vnode.h> 54 #include <sys/mount.h> 55 #include <sys/namei.h> 56 #include <miscfs/nullfs/null.h> 57 58 static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure"); 59 60 static int nullfs_fhtovp(struct mount *mp, struct fid *fidp, 61 struct vnode **vpp); 62 static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam, 63 int *extflagsp, struct ucred **credanonp); 64 static int nullfs_mount(struct mount *mp, char *path, caddr_t data, 65 struct nameidata *ndp, struct proc *p); 66 static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, 67 caddr_t arg, struct proc *p); 68 static int nullfs_root(struct mount *mp, struct vnode **vpp); 69 static int nullfs_start(struct mount *mp, int flags, struct proc *p); 70 static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 71 struct proc *p); 72 static int nullfs_sync(struct mount *mp, int waitfor, 73 struct ucred *cred, struct proc *p); 74 static int nullfs_unmount(struct mount *mp, int mntflags, struct proc *p); 75 static int nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp); 76 static int nullfs_vptofh(struct vnode *vp, struct fid *fhp); 77 static int nullfs_extattrctl(struct mount *mp, int cmd, 78 const char *attrname, caddr_t arg, 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(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 197 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); 198 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 199 &size); 200 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 201 (void)nullfs_statfs(mp, &mp->mnt_stat, p); 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, p) 214 struct mount *mp; 215 int flags; 216 struct proc *p; 217 { 218 return (0); 219 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */ 220 } 221 222 /* 223 * Free reference to null layer 224 */ 225 static int 226 nullfs_unmount(mp, mntflags, p) 227 struct mount *mp; 228 int mntflags; 229 struct proc *p; 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 proc *p = curproc; /* 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, p); 280 *vpp = vp; 281 return 0; 282 } 283 284 static int 285 nullfs_quotactl(mp, cmd, uid, arg, p) 286 struct mount *mp; 287 int cmd; 288 uid_t uid; 289 caddr_t arg; 290 struct proc *p; 291 { 292 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p); 293 } 294 295 static int 296 nullfs_statfs(mp, sbp, p) 297 struct mount *mp; 298 struct statfs *sbp; 299 struct proc *p; 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, p); 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, p) 334 struct mount *mp; 335 int waitfor; 336 struct ucred *cred; 337 struct proc *p; 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, vpp) 347 struct mount *mp; 348 ino_t ino; 349 struct vnode **vpp; 350 { 351 352 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 353 } 354 355 static int 356 nullfs_fhtovp(mp, fidp, vpp) 357 struct mount *mp; 358 struct fid *fidp; 359 struct vnode **vpp; 360 { 361 362 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 363 } 364 365 static int 366 nullfs_checkexp(mp, nam, extflagsp, credanonp) 367 struct mount *mp; 368 struct sockaddr *nam; 369 int *extflagsp; 370 struct ucred **credanonp; 371 { 372 373 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 374 extflagsp, credanonp); 375 } 376 377 static int 378 nullfs_vptofh(vp, fhp) 379 struct vnode *vp; 380 struct fid *fhp; 381 { 382 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 383 } 384 385 static int 386 nullfs_extattrctl(mp, cmd, attrname, arg, p) 387 struct mount *mp; 388 int cmd; 389 const char *attrname; 390 caddr_t arg; 391 struct proc *p; 392 { 393 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, 394 arg, p); 395 } 396 397 398 static struct vfsops null_vfsops = { 399 nullfs_mount, 400 nullfs_start, 401 nullfs_unmount, 402 nullfs_root, 403 nullfs_quotactl, 404 nullfs_statfs, 405 nullfs_sync, 406 nullfs_vget, 407 nullfs_fhtovp, 408 nullfs_checkexp, 409 nullfs_vptofh, 410 nullfs_init, 411 nullfs_uninit, 412 nullfs_extattrctl, 413 }; 414 415 VFS_SET(null_vfsops, null, VFCF_LOOPBACK); 416