null_vfsops.c revision 76166
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 76166 2001-05-01 08:13:21Z markm $ 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 <miscfs/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, char *path, caddr_t data, 66 struct nameidata *ndp, struct proc *p); 67static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, 68 caddr_t arg, struct proc *p); 69static int nullfs_root(struct mount *mp, struct vnode **vpp); 70static int nullfs_start(struct mount *mp, int flags, struct proc *p); 71static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 72 struct proc *p); 73static int nullfs_sync(struct mount *mp, int waitfor, 74 struct ucred *cred, struct proc *p); 75static int nullfs_unmount(struct mount *mp, int mntflags, struct proc *p); 76static int nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp); 77static int nullfs_vptofh(struct vnode *vp, struct fid *fhp); 78static int nullfs_extattrctl(struct mount *mp, int cmd, 79 struct vnode *filename_vp, 80 int namespace, const char *attrname, 81 struct proc *p); 82 83/* 84 * Mount null layer 85 */ 86static int 87nullfs_mount(mp, path, data, ndp, p) 88 struct mount *mp; 89 char *path; 90 caddr_t data; 91 struct nameidata *ndp; 92 struct proc *p; 93{ 94 int error = 0; 95 struct null_args args; 96 struct vnode *lowerrootvp, *vp; 97 struct vnode *nullm_rootvp; 98 struct null_mount *xmp; 99 u_int size; 100 int isvnunlocked = 0; 101 102 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 103 104 /* 105 * Update is a no-op 106 */ 107 if (mp->mnt_flag & MNT_UPDATE) { 108 return (EOPNOTSUPP); 109 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/ 110 } 111 112 /* 113 * Get argument 114 */ 115 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 116 if (error) 117 return (error); 118 119 /* 120 * Unlock lower node to avoid deadlock. 121 * (XXX) VOP_ISLOCKED is needed? 122 */ 123 if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) && 124 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 125 VOP_UNLOCK(mp->mnt_vnodecovered, 0, p); 126 isvnunlocked = 1; 127 } 128 /* 129 * Find lower node 130 */ 131 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 132 UIO_USERSPACE, args.target, p); 133 error = namei(ndp); 134 /* 135 * Re-lock vnode. 136 */ 137 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 138 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, p); 139 140 if (error) 141 return (error); 142 NDFREE(ndp, NDF_ONLY_PNBUF); 143 144 /* 145 * Sanity check on lower vnode 146 */ 147 lowerrootvp = ndp->ni_vp; 148 149 vrele(ndp->ni_dvp); 150 ndp->ni_dvp = NULLVP; 151 152 /* 153 * Check multi null mount to avoid `lock against myself' panic. 154 */ 155 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 156 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 157 vput(lowerrootvp); 158 return (EDEADLK); 159 } 160 161 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 162 M_NULLFSMNT, M_WAITOK); /* XXX */ 163 164 /* 165 * Save reference to underlying FS 166 */ 167 xmp->nullm_vfs = lowerrootvp->v_mount; 168 169 /* 170 * Save reference. Each mount also holds 171 * a reference on the root vnode. 172 */ 173 error = null_node_create(mp, lowerrootvp, &vp); 174 /* 175 * Unlock the node (either the lower or the alias) 176 */ 177 VOP_UNLOCK(vp, 0, p); 178 /* 179 * Make sure the node alias worked 180 */ 181 if (error) { 182 vrele(lowerrootvp); 183 free(xmp, M_NULLFSMNT); /* XXX */ 184 return (error); 185 } 186 187 /* 188 * Keep a held reference to the root vnode. 189 * It is vrele'd in nullfs_unmount. 190 */ 191 nullm_rootvp = vp; 192 nullm_rootvp->v_flag |= VROOT; 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) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 200 &size); 201 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 202 (void)nullfs_statfs(mp, &mp->mnt_stat, p); 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, p) 215 struct mount *mp; 216 int flags; 217 struct proc *p; 218{ 219 return (0); 220 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */ 221} 222 223/* 224 * Free reference to null layer 225 */ 226static int 227nullfs_unmount(mp, mntflags, p) 228 struct mount *mp; 229 int mntflags; 230 struct proc *p; 231{ 232 struct vnode *vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 233 void *mntdata; 234 int error; 235 int flags = 0; 236 237 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 238 239 if (mntflags & MNT_FORCE) 240 flags |= FORCECLOSE; 241 242 error = VFS_ROOT(mp, &vp); 243 if (error) 244 return (error); 245 if (vp->v_usecount > 2) { 246 NULLFSDEBUG("nullfs_unmount: rootvp is busy(%d)\n", 247 vp->v_usecount); 248 vput(vp); 249 return (EBUSY); 250 } 251 error = vflush(mp, vp, flags); 252 if (error) 253 return (error); 254 255#ifdef NULLFS_DEBUG 256 vprint("alias root of lower", vp); 257#endif 258 vput(vp); 259 /* 260 * Release reference on underlying root vnode 261 */ 262 vrele(vp); 263 /* 264 * And blow it away for future re-use 265 */ 266 vgone(vp); 267 /* 268 * Finally, throw away the null_mount structure 269 */ 270 mntdata = mp->mnt_data; 271 mp->mnt_data = 0; 272 free(mntdata, M_NULLFSMNT); 273 return 0; 274} 275 276static int 277nullfs_root(mp, vpp) 278 struct mount *mp; 279 struct vnode **vpp; 280{ 281 struct proc *p = curproc; /* XXX */ 282 struct vnode *vp; 283 284 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 285 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 286 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 287 288 /* 289 * Return locked reference to root. 290 */ 291 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 292 VREF(vp); 293 294#ifdef NULLFS_DEBUG 295 if (VOP_ISLOCKED(vp, NULL)) { 296 Debugger("root vnode is locked.\n"); 297 vrele(vp); 298 return (EDEADLK); 299 } 300#endif 301 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 302 *vpp = vp; 303 return 0; 304} 305 306static int 307nullfs_quotactl(mp, cmd, uid, arg, p) 308 struct mount *mp; 309 int cmd; 310 uid_t uid; 311 caddr_t arg; 312 struct proc *p; 313{ 314 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p); 315} 316 317static int 318nullfs_statfs(mp, sbp, p) 319 struct mount *mp; 320 struct statfs *sbp; 321 struct proc *p; 322{ 323 int error; 324 struct statfs mstat; 325 326 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 327 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 328 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 329 330 bzero(&mstat, sizeof(mstat)); 331 332 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p); 333 if (error) 334 return (error); 335 336 /* now copy across the "interesting" information and fake the rest */ 337 sbp->f_type = mstat.f_type; 338 sbp->f_flags = mstat.f_flags; 339 sbp->f_bsize = mstat.f_bsize; 340 sbp->f_iosize = mstat.f_iosize; 341 sbp->f_blocks = mstat.f_blocks; 342 sbp->f_bfree = mstat.f_bfree; 343 sbp->f_bavail = mstat.f_bavail; 344 sbp->f_files = mstat.f_files; 345 sbp->f_ffree = mstat.f_ffree; 346 if (sbp != &mp->mnt_stat) { 347 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 348 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 349 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 350 } 351 return (0); 352} 353 354static int 355nullfs_sync(mp, waitfor, cred, p) 356 struct mount *mp; 357 int waitfor; 358 struct ucred *cred; 359 struct proc *p; 360{ 361 /* 362 * XXX - Assumes no data cached at null layer. 363 */ 364 return (0); 365} 366 367static int 368nullfs_vget(mp, ino, vpp) 369 struct mount *mp; 370 ino_t ino; 371 struct vnode **vpp; 372{ 373 int error; 374 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 375 if (error) 376 return (error); 377 378 return (null_node_create(mp, *vpp, vpp)); 379} 380 381static int 382nullfs_fhtovp(mp, fidp, vpp) 383 struct mount *mp; 384 struct fid *fidp; 385 struct vnode **vpp; 386{ 387 int error; 388 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 389 if (error) 390 return (error); 391 392 return (null_node_create(mp, *vpp, vpp)); 393} 394 395static int 396nullfs_checkexp(mp, nam, extflagsp, credanonp) 397 struct mount *mp; 398 struct sockaddr *nam; 399 int *extflagsp; 400 struct ucred **credanonp; 401{ 402 403 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 404 extflagsp, credanonp); 405} 406 407static int 408nullfs_vptofh(vp, fhp) 409 struct vnode *vp; 410 struct fid *fhp; 411{ 412 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 413} 414 415static int 416nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname, p) 417 struct mount *mp; 418 int cmd; 419 struct vnode *filename_vp; 420 int namespace; 421 const char *attrname; 422 struct proc *p; 423{ 424 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp, 425 namespace, attrname, p); 426} 427 428 429static struct vfsops null_vfsops = { 430 nullfs_mount, 431 nullfs_start, 432 nullfs_unmount, 433 nullfs_root, 434 nullfs_quotactl, 435 nullfs_statfs, 436 nullfs_sync, 437 nullfs_vget, 438 nullfs_fhtovp, 439 nullfs_checkexp, 440 nullfs_vptofh, 441 nullfs_init, 442 nullfs_uninit, 443 nullfs_extattrctl, 444}; 445 446VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK); 447