null_vfsops.c revision 101308
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: head/sys/fs/nullfs/null_vfsops.c 101308 2002-08-04 10:29:36Z jeff $ 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 59static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure"); 60 61static int nullfs_fhtovp(struct mount *mp, struct fid *fidp, 62 struct vnode **vpp); 63static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam, 64 int *extflagsp, struct ucred **credanonp); 65static int nullfs_mount(struct mount *mp, struct nameidata *ndp, 66 struct thread *td); 67static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, 68 caddr_t arg, struct thread *td); 69static int nullfs_root(struct mount *mp, struct vnode **vpp); 70static int nullfs_start(struct mount *mp, int flags, struct thread *td); 71static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 72 struct thread *td); 73static int nullfs_sync(struct mount *mp, int waitfor, 74 struct ucred *cred, struct thread *td); 75static int nullfs_unmount(struct mount *mp, int mntflags, struct thread *td); 76static int nullfs_vget(struct mount *mp, ino_t ino, int flags, 77 struct vnode **vpp); 78static int nullfs_vptofh(struct vnode *vp, struct fid *fhp); 79static 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 */ 87static int 88nullfs_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 mp_fixme("Unlocked vflag access"); 191 nullm_rootvp = vp; 192 nullm_rootvp->v_vflag |= VV_ROOT; 193 xmp->nullm_rootvp = nullm_rootvp; 194 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 195 mp->mnt_flag |= MNT_LOCAL; 196 mp->mnt_data = (qaddr_t) xmp; 197 vfs_getnewfsid(mp); 198 199 (void) copystr(target, mp->mnt_stat.f_mntfromname, 200 MNAMELEN - 1, &size); 201 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 202 (void)nullfs_statfs(mp, &mp->mnt_stat, td); 203 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 204 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 205 return (0); 206} 207 208/* 209 * VFS start. Nothing needed here - the start routine 210 * on the underlying filesystem will have been called 211 * when that filesystem was mounted. 212 */ 213static int 214nullfs_start(mp, flags, td) 215 struct mount *mp; 216 int flags; 217 struct thread *td; 218{ 219 return (0); 220 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */ 221} 222 223/* 224 * Free reference to null layer 225 */ 226static int 227nullfs_unmount(mp, mntflags, td) 228 struct mount *mp; 229 int mntflags; 230 struct thread *td; 231{ 232 void *mntdata; 233 int error; 234 int flags = 0; 235 236 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 237 238 if (mntflags & MNT_FORCE) 239 flags |= FORCECLOSE; 240 241 /* There is 1 extra root vnode reference (nullm_rootvp). */ 242 error = vflush(mp, 1, flags); 243 if (error) 244 return (error); 245 246 /* 247 * Finally, throw away the null_mount structure 248 */ 249 mntdata = mp->mnt_data; 250 mp->mnt_data = 0; 251 free(mntdata, M_NULLFSMNT); 252 return 0; 253} 254 255static int 256nullfs_root(mp, vpp) 257 struct mount *mp; 258 struct vnode **vpp; 259{ 260 struct thread *td = curthread; /* XXX */ 261 struct vnode *vp; 262 263 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 264 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 265 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 266 267 /* 268 * Return locked reference to root. 269 */ 270 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 271 VREF(vp); 272 273#ifdef NULLFS_DEBUG 274 if (VOP_ISLOCKED(vp, NULL)) { 275 Debugger("root vnode is locked.\n"); 276 vrele(vp); 277 return (EDEADLK); 278 } 279#endif 280 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 281 *vpp = vp; 282 return 0; 283} 284 285static int 286nullfs_quotactl(mp, cmd, uid, arg, td) 287 struct mount *mp; 288 int cmd; 289 uid_t uid; 290 caddr_t arg; 291 struct thread *td; 292{ 293 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); 294} 295 296static int 297nullfs_statfs(mp, sbp, td) 298 struct mount *mp; 299 struct statfs *sbp; 300 struct thread *td; 301{ 302 int error; 303 struct statfs mstat; 304 305 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 306 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 307 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 308 309 bzero(&mstat, sizeof(mstat)); 310 311 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); 312 if (error) 313 return (error); 314 315 /* now copy across the "interesting" information and fake the rest */ 316 sbp->f_type = mstat.f_type; 317 sbp->f_flags = mstat.f_flags; 318 sbp->f_bsize = mstat.f_bsize; 319 sbp->f_iosize = mstat.f_iosize; 320 sbp->f_blocks = mstat.f_blocks; 321 sbp->f_bfree = mstat.f_bfree; 322 sbp->f_bavail = mstat.f_bavail; 323 sbp->f_files = mstat.f_files; 324 sbp->f_ffree = mstat.f_ffree; 325 if (sbp != &mp->mnt_stat) { 326 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 327 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 328 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 329 } 330 return (0); 331} 332 333static int 334nullfs_sync(mp, waitfor, cred, td) 335 struct mount *mp; 336 int waitfor; 337 struct ucred *cred; 338 struct thread *td; 339{ 340 /* 341 * XXX - Assumes no data cached at null layer. 342 */ 343 return (0); 344} 345 346static int 347nullfs_vget(mp, ino, flags, vpp) 348 struct mount *mp; 349 ino_t ino; 350 int flags; 351 struct vnode **vpp; 352{ 353 int error; 354 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp); 355 if (error) 356 return (error); 357 358 return (null_nodeget(mp, *vpp, vpp)); 359} 360 361static int 362nullfs_fhtovp(mp, fidp, vpp) 363 struct mount *mp; 364 struct fid *fidp; 365 struct vnode **vpp; 366{ 367 int error; 368 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 369 if (error) 370 return (error); 371 372 return (null_nodeget(mp, *vpp, vpp)); 373} 374 375static int 376nullfs_checkexp(mp, nam, extflagsp, credanonp) 377 struct mount *mp; 378 struct sockaddr *nam; 379 int *extflagsp; 380 struct ucred **credanonp; 381{ 382 383 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 384 extflagsp, credanonp); 385} 386 387static int 388nullfs_vptofh(vp, fhp) 389 struct vnode *vp; 390 struct fid *fhp; 391{ 392 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 393} 394 395static int 396nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname, td) 397 struct mount *mp; 398 int cmd; 399 struct vnode *filename_vp; 400 int namespace; 401 const char *attrname; 402 struct thread *td; 403{ 404 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp, 405 namespace, attrname, td); 406} 407 408 409static struct vfsops null_vfsops = { 410 NULL, 411 nullfs_start, 412 nullfs_unmount, 413 nullfs_root, 414 nullfs_quotactl, 415 nullfs_statfs, 416 nullfs_sync, 417 nullfs_vget, 418 nullfs_fhtovp, 419 nullfs_checkexp, 420 nullfs_vptofh, 421 nullfs_init, 422 nullfs_uninit, 423 nullfs_extattrctl, 424 nullfs_mount, 425}; 426 427VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK); 428