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