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 * $Id: null_vfsops.c,v 1.15 1997/04/17 11:17:29 kato 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/time.h> 52 #include <sys/types.h> 53 #include <sys/vnode.h> 54 #include <sys/mount.h> 55 #include <sys/namei.h> 56 #include <sys/malloc.h> 57 #include <miscfs/nullfs/null.h> 58 59 static int nullfs_fhtovp __P((struct mount *mp, struct fid *fidp, 60 struct mbuf *nam, struct vnode **vpp, 61 int *exflagsp, struct ucred **credanonp)); 62 static int nullfs_mount __P((struct mount *mp, char *path, caddr_t data, 63 struct nameidata *ndp, struct proc *p)); 64 static int nullfs_quotactl __P((struct mount *mp, int cmd, uid_t uid, 65 caddr_t arg, struct proc *p)); 66 static int nullfs_root __P((struct mount *mp, struct vnode **vpp)); 67 static int nullfs_start __P((struct mount *mp, int flags, struct proc *p)); 68 static int nullfs_statfs __P((struct mount *mp, struct statfs *sbp, 69 struct proc *p)); 70 static int nullfs_sync __P((struct mount *mp, int waitfor, 71 struct ucred *cred, struct proc *p)); 72 static int nullfs_unmount __P((struct mount *mp, int mntflags, 73 struct proc *p)); 74 static int nullfs_vget __P((struct mount *mp, ino_t ino, 75 struct vnode **vpp)); 76 static int nullfs_vptofh __P((struct vnode *vp, struct fid *fhp)); 77 78 /* 79 * Mount null layer 80 */ 81 static int 82 nullfs_mount(mp, path, data, ndp, p) 83 struct mount *mp; 84 char *path; 85 caddr_t data; 86 struct nameidata *ndp; 87 struct proc *p; 88 { 89 int error = 0; 90 struct null_args args; 91 struct vnode *lowerrootvp, *vp; 92 struct vnode *nullm_rootvp; 93 struct null_mount *xmp; 94 u_int size; 95 int isvnunlocked = 0; 96 97 #ifdef NULLFS_DIAGNOSTIC 98 printf("nullfs_mount(mp = %x)\n", mp); 99 #endif 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)) { 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)) 135 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, p); 136 137 if (error) 138 return (error); 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 error = EDEADLK; 153 return (error); 154 } 155 156 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 157 M_UFSMNT, M_WAITOK); /* XXX */ 158 159 /* 160 * Save reference to underlying FS 161 */ 162 xmp->nullm_vfs = lowerrootvp->v_mount; 163 164 /* 165 * Save reference. Each mount also holds 166 * a reference on the root vnode. 167 */ 168 error = null_node_create(mp, lowerrootvp, &vp); 169 /* 170 * Unlock the node (either the lower or the alias) 171 */ 172 VOP_UNLOCK(vp, 0, p); 173 /* 174 * Make sure the node alias worked 175 */ 176 if (error) { 177 vrele(lowerrootvp); 178 free(xmp, M_UFSMNT); /* XXX */ 179 return (error); 180 } 181 182 /* 183 * Keep a held reference to the root vnode. 184 * It is vrele'd in nullfs_unmount. 185 */ 186 nullm_rootvp = vp; 187 nullm_rootvp->v_flag |= VROOT; 188 xmp->nullm_rootvp = nullm_rootvp; 189 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 190 mp->mnt_flag |= MNT_LOCAL; 191 mp->mnt_data = (qaddr_t) xmp; 192 vfs_getnewfsid(mp); 193 194 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 195 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); 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 #ifdef NULLFS_DIAGNOSTIC 200 printf("nullfs_mount: lower %s, alias at %s\n", 201 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 202 #endif 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 struct vnode *nullm_rootvp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 231 int error; 232 int flags = 0; 233 234 #ifdef NULLFS_DIAGNOSTIC 235 printf("nullfs_unmount(mp = %x)\n", mp); 236 #endif 237 238 if (mntflags & MNT_FORCE) 239 flags |= FORCECLOSE; 240 241 /* 242 * Clear out buffer cache. I don't think we 243 * ever get anything cached at this level at the 244 * moment, but who knows... 245 */ 246 #if 0 247 mntflushbuf(mp, 0); 248 if (mntinvalbuf(mp, 1)) 249 return (EBUSY); 250 #endif 251 if (nullm_rootvp->v_usecount > 1) 252 return (EBUSY); 253 error = vflush(mp, nullm_rootvp, flags); 254 if (error) 255 return (error); 256 257 #ifdef NULLFS_DIAGNOSTIC 258 vprint("alias root of lower", nullm_rootvp); 259 #endif 260 /* 261 * Release reference on underlying root vnode 262 */ 263 vrele(nullm_rootvp); 264 /* 265 * And blow it away for future re-use 266 */ 267 vgone(nullm_rootvp); 268 /* 269 * Finally, throw away the null_mount structure 270 */ 271 free(mp->mnt_data, M_UFSMNT); /* XXX */ 272 mp->mnt_data = 0; 273 return 0; 274 } 275 276 static int 277 nullfs_root(mp, vpp) 278 struct mount *mp; 279 struct vnode **vpp; 280 { 281 struct proc *p = curproc; /* XXX */ 282 struct vnode *vp; 283 284 #ifdef NULLFS_DIAGNOSTIC 285 printf("nullfs_root(mp = %x, vp = %x->%x)\n", mp, 286 MOUNTTONULLMOUNT(mp)->nullm_rootvp, 287 NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp) 288 ); 289 #endif 290 291 /* 292 * Return locked reference to root. 293 */ 294 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 295 VREF(vp); 296 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 297 *vpp = vp; 298 return 0; 299 } 300 301 static int 302 nullfs_quotactl(mp, cmd, uid, arg, p) 303 struct mount *mp; 304 int cmd; 305 uid_t uid; 306 caddr_t arg; 307 struct proc *p; 308 { 309 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p); 310 } 311 312 static int 313 nullfs_statfs(mp, sbp, p) 314 struct mount *mp; 315 struct statfs *sbp; 316 struct proc *p; 317 { 318 int error; 319 struct statfs mstat; 320 321 #ifdef NULLFS_DIAGNOSTIC 322 printf("nullfs_statfs(mp = %x, vp = %x->%x)\n", mp, 323 MOUNTTONULLMOUNT(mp)->nullm_rootvp, 324 NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp) 325 ); 326 #endif 327 328 bzero(&mstat, sizeof(mstat)); 329 330 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p); 331 if (error) 332 return (error); 333 334 /* now copy across the "interesting" information and fake the rest */ 335 sbp->f_type = mstat.f_type; 336 sbp->f_flags = mstat.f_flags; 337 sbp->f_bsize = mstat.f_bsize; 338 sbp->f_iosize = mstat.f_iosize; 339 sbp->f_blocks = mstat.f_blocks; 340 sbp->f_bfree = mstat.f_bfree; 341 sbp->f_bavail = mstat.f_bavail; 342 sbp->f_files = mstat.f_files; 343 sbp->f_ffree = mstat.f_ffree; 344 if (sbp != &mp->mnt_stat) { 345 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 346 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 347 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 348 } 349 return (0); 350 } 351 352 static int 353 nullfs_sync(mp, waitfor, cred, p) 354 struct mount *mp; 355 int waitfor; 356 struct ucred *cred; 357 struct proc *p; 358 { 359 /* 360 * XXX - Assumes no data cached at null layer. 361 */ 362 return (0); 363 } 364 365 static int 366 nullfs_vget(mp, ino, vpp) 367 struct mount *mp; 368 ino_t ino; 369 struct vnode **vpp; 370 { 371 372 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 373 } 374 375 static int 376 nullfs_fhtovp(mp, fidp, nam, vpp, exflagsp, credanonp) 377 struct mount *mp; 378 struct fid *fidp; 379 struct mbuf *nam; 380 struct vnode **vpp; 381 int *exflagsp; 382 struct ucred**credanonp; 383 { 384 385 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, nam, vpp, exflagsp,credanonp); 386 } 387 388 static int 389 nullfs_vptofh(vp, fhp) 390 struct vnode *vp; 391 struct fid *fhp; 392 { 393 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 394 } 395 396 static struct vfsops null_vfsops = { 397 nullfs_mount, 398 nullfs_start, 399 nullfs_unmount, 400 nullfs_root, 401 nullfs_quotactl, 402 nullfs_statfs, 403 nullfs_sync, 404 nullfs_vget, 405 nullfs_fhtovp, 406 nullfs_vptofh, 407 nullfs_init, 408 }; 409 410 VFS_SET(null_vfsops, null, MOUNT_NULL, VFCF_LOOPBACK); 411