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 1.6 2003/09/23 05:03:53 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 "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 thread *td); 66 static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, 67 caddr_t arg, struct thread *td); 68 static int nullfs_root(struct mount *mp, struct vnode **vpp); 69 static int nullfs_start(struct mount *mp, int flags, struct thread *td); 70 static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 71 struct thread *td); 72 static int nullfs_sync(struct mount *mp, int waitfor, struct thread *td); 73 static int nullfs_unmount(struct mount *mp, int mntflags, struct thread *td); 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 thread *td); 78 79 /* 80 * Mount null layer 81 */ 82 static int 83 nullfs_mount(mp, path, data, ndp, td) 84 struct mount *mp; 85 char *path; 86 caddr_t data; 87 struct nameidata *ndp; 88 struct thread *td; 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, td); 122 isvnunlocked = 1; 123 } 124 /* 125 * Find lower node 126 */ 127 NDINIT(ndp, NAMEI_LOOKUP, CNP_FOLLOW | CNP_WANTPARENT | CNP_LOCKLEAF, 128 UIO_USERSPACE, args.target, td); 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, td); 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, td); 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, td); 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(struct mount *mp, int flags, struct thread *td) 213 { 214 return (0); 215 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */ 216 } 217 218 /* 219 * Free reference to null layer 220 */ 221 static int 222 nullfs_unmount(struct mount *mp, int mntflags, struct thread *td) 223 { 224 void *mntdata; 225 int error; 226 int flags = 0; 227 228 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 229 230 if (mntflags & MNT_FORCE) 231 flags |= FORCECLOSE; 232 233 /* There is 1 extra root vnode reference (nullm_rootvp). */ 234 error = vflush(mp, 1, flags); 235 if (error) 236 return (error); 237 238 /* 239 * Finally, throw away the null_mount structure 240 */ 241 mntdata = mp->mnt_data; 242 mp->mnt_data = 0; 243 free(mntdata, M_NULLFSMNT); 244 return 0; 245 } 246 247 static int 248 nullfs_root(struct mount *mp, struct vnode **vpp) 249 { 250 struct thread *td = curthread; /* XXX */ 251 struct vnode *vp; 252 253 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 254 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 255 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 256 257 /* 258 * Return locked reference to root. 259 */ 260 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 261 VREF(vp); 262 263 #ifdef NULLFS_DEBUG 264 if (VOP_ISLOCKED(vp, NULL)) { 265 Debugger("root vnode is locked.\n"); 266 vrele(vp); 267 return (EDEADLK); 268 } 269 #endif 270 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 271 *vpp = vp; 272 return 0; 273 } 274 275 static int 276 nullfs_quotactl(mp, cmd, uid, arg, td) 277 struct mount *mp; 278 int cmd; 279 uid_t uid; 280 caddr_t arg; 281 struct thread *td; 282 { 283 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); 284 } 285 286 static int 287 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td) 288 { 289 int error; 290 struct statfs mstat; 291 292 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 293 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 294 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 295 296 bzero(&mstat, sizeof(mstat)); 297 298 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); 299 if (error) 300 return (error); 301 302 /* now copy across the "interesting" information and fake the rest */ 303 sbp->f_type = mstat.f_type; 304 sbp->f_flags = mstat.f_flags; 305 sbp->f_bsize = mstat.f_bsize; 306 sbp->f_iosize = mstat.f_iosize; 307 sbp->f_blocks = mstat.f_blocks; 308 sbp->f_bfree = mstat.f_bfree; 309 sbp->f_bavail = mstat.f_bavail; 310 sbp->f_files = mstat.f_files; 311 sbp->f_ffree = mstat.f_ffree; 312 if (sbp != &mp->mnt_stat) { 313 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 314 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 315 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 316 } 317 return (0); 318 } 319 320 static int 321 nullfs_sync(mp, waitfor, td) 322 struct mount *mp; 323 int waitfor; 324 struct thread *td; 325 { 326 /* 327 * XXX - Assumes no data cached at null layer. 328 */ 329 return (0); 330 } 331 332 static int 333 nullfs_vget(mp, ino, vpp) 334 struct mount *mp; 335 ino_t ino; 336 struct vnode **vpp; 337 { 338 339 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 340 } 341 342 static int 343 nullfs_fhtovp(mp, fidp, vpp) 344 struct mount *mp; 345 struct fid *fidp; 346 struct vnode **vpp; 347 { 348 349 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 350 } 351 352 static int 353 nullfs_checkexp(mp, nam, extflagsp, credanonp) 354 struct mount *mp; 355 struct sockaddr *nam; 356 int *extflagsp; 357 struct ucred **credanonp; 358 { 359 360 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 361 extflagsp, credanonp); 362 } 363 364 static int 365 nullfs_vptofh(vp, fhp) 366 struct vnode *vp; 367 struct fid *fhp; 368 { 369 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 370 } 371 372 static int 373 nullfs_extattrctl(mp, cmd, attrname, arg, td) 374 struct mount *mp; 375 int cmd; 376 const char *attrname; 377 caddr_t arg; 378 struct thread *td; 379 { 380 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, 381 arg, td); 382 } 383 384 385 static struct vfsops null_vfsops = { 386 nullfs_mount, 387 nullfs_start, 388 nullfs_unmount, 389 nullfs_root, 390 nullfs_quotactl, 391 nullfs_statfs, 392 nullfs_sync, 393 nullfs_vget, 394 nullfs_fhtovp, 395 nullfs_checkexp, 396 nullfs_vptofh, 397 nullfs_init, 398 nullfs_uninit, 399 nullfs_extattrctl, 400 }; 401 402 VFS_SET(null_vfsops, null, VFCF_LOOPBACK); 403