null_vfsops.c revision 65467
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 65467 2000-09-05 09:02:07Z bp $ 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 57static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure"); 58 59static int nullfs_fhtovp(struct mount *mp, struct fid *fidp, 60 struct vnode **vpp); 61static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam, 62 int *extflagsp, struct ucred **credanonp); 63static int nullfs_mount(struct mount *mp, char *path, caddr_t data, 64 struct nameidata *ndp, struct proc *p); 65static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, 66 caddr_t arg, struct proc *p); 67static int nullfs_root(struct mount *mp, struct vnode **vpp); 68static int nullfs_start(struct mount *mp, int flags, struct proc *p); 69static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 70 struct proc *p); 71static int nullfs_sync(struct mount *mp, int waitfor, 72 struct ucred *cred, struct proc *p); 73static int nullfs_unmount(struct mount *mp, int mntflags, struct proc *p); 74static int nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp); 75static int nullfs_vptofh(struct vnode *vp, struct fid *fhp); 76 77/* 78 * Mount null layer 79 */ 80static int 81nullfs_mount(mp, path, data, ndp, p) 82 struct mount *mp; 83 char *path; 84 caddr_t data; 85 struct nameidata *ndp; 86 struct proc *p; 87{ 88 int error = 0; 89 struct null_args args; 90 struct vnode *lowerrootvp, *vp; 91 struct vnode *nullm_rootvp; 92 struct null_mount *xmp; 93 u_int size; 94 int isvnunlocked = 0; 95 96 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 97 98 /* 99 * Update is a no-op 100 */ 101 if (mp->mnt_flag & MNT_UPDATE) { 102 return (EOPNOTSUPP); 103 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/ 104 } 105 106 /* 107 * Get argument 108 */ 109 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 110 if (error) 111 return (error); 112 113 /* 114 * Unlock lower node to avoid deadlock. 115 * (XXX) VOP_ISLOCKED is needed? 116 */ 117 if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) && 118 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 119 VOP_UNLOCK(mp->mnt_vnodecovered, 0, p); 120 isvnunlocked = 1; 121 } 122 /* 123 * Find lower node 124 */ 125 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 126 UIO_USERSPACE, args.target, p); 127 error = namei(ndp); 128 /* 129 * Re-lock vnode. 130 */ 131 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 132 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, p); 133 134 if (error) 135 return (error); 136 NDFREE(ndp, NDF_ONLY_PNBUF); 137 138 /* 139 * Sanity check on lower vnode 140 */ 141 lowerrootvp = ndp->ni_vp; 142 143 vrele(ndp->ni_dvp); 144 ndp->ni_dvp = NULLVP; 145 146 /* 147 * Check multi null mount to avoid `lock against myself' panic. 148 */ 149 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 150 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 151 return (EDEADLK); 152 } 153 154 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 155 M_NULLFSMNT, M_WAITOK); /* XXX */ 156 157 /* 158 * Save reference to underlying FS 159 */ 160 xmp->nullm_vfs = lowerrootvp->v_mount; 161 162 /* 163 * Save reference. Each mount also holds 164 * a reference on the root vnode. 165 */ 166 error = null_node_create(mp, lowerrootvp, &vp); 167 /* 168 * Unlock the node (either the lower or the alias) 169 */ 170 VOP_UNLOCK(vp, 0, p); 171 /* 172 * Make sure the node alias worked 173 */ 174 if (error) { 175 vrele(lowerrootvp); 176 free(xmp, M_NULLFSMNT); /* XXX */ 177 return (error); 178 } 179 180 /* 181 * Keep a held reference to the root vnode. 182 * It is vrele'd in nullfs_unmount. 183 */ 184 nullm_rootvp = vp; 185 nullm_rootvp->v_flag |= VROOT; 186 xmp->nullm_rootvp = nullm_rootvp; 187 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 188 mp->mnt_flag |= MNT_LOCAL; 189 mp->mnt_data = (qaddr_t) xmp; 190 vfs_getnewfsid(mp); 191 192 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 193 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); 194 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 195 &size); 196 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 197 (void)nullfs_statfs(mp, &mp->mnt_stat, p); 198 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 199 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 200 return (0); 201} 202 203/* 204 * VFS start. Nothing needed here - the start routine 205 * on the underlying filesystem will have been called 206 * when that filesystem was mounted. 207 */ 208static int 209nullfs_start(mp, flags, p) 210 struct mount *mp; 211 int flags; 212 struct proc *p; 213{ 214 return (0); 215 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */ 216} 217 218/* 219 * Free reference to null layer 220 */ 221static int 222nullfs_unmount(mp, mntflags, p) 223 struct mount *mp; 224 int mntflags; 225 struct proc *p; 226{ 227 struct vnode *nullm_rootvp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 228 void *mntdata; 229 int error; 230 int flags = 0; 231 232 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 233 234 if (mntflags & MNT_FORCE) 235 flags |= FORCECLOSE; 236 237 /* 238 * Clear out buffer cache. I don't think we 239 * ever get anything cached at this level at the 240 * moment, but who knows... 241 */ 242#if 0 243 mntflushbuf(mp, 0); 244 if (mntinvalbuf(mp, 1)) 245 return (EBUSY); 246#endif 247 if (nullm_rootvp->v_usecount > 1) 248 return (EBUSY); 249 error = vflush(mp, nullm_rootvp, flags); 250 if (error) 251 return (error); 252 253#ifdef NULLFS_DEBUG 254 vprint("alias root of lower", nullm_rootvp); 255#endif 256 /* 257 * Release reference on underlying root vnode 258 */ 259 vrele(nullm_rootvp); 260 /* 261 * And blow it away for future re-use 262 */ 263 vgone(nullm_rootvp); 264 /* 265 * Finally, throw away the null_mount structure 266 */ 267 mntdata = mp->mnt_data; 268 mp->mnt_data = 0; 269 free(mntdata, M_NULLFSMNT); /* XXX */ 270 return 0; 271} 272 273static int 274nullfs_root(mp, vpp) 275 struct mount *mp; 276 struct vnode **vpp; 277{ 278 struct proc *p = curproc; /* XXX */ 279 struct vnode *vp; 280 281 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 282 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 283 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 284 285 /* 286 * Return locked reference to root. 287 */ 288 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 289 VREF(vp); 290#ifdef NULLFS_DEBUG 291 if (VOP_ISLOCKED(vp, NULL)) { 292 /* 293 * XXX 294 * Should we check type of node? 295 */ 296 printf("nullfs_root: multi null mount?\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{ 373 374 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 375} 376 377static int 378nullfs_fhtovp(mp, fidp, vpp) 379 struct mount *mp; 380 struct fid *fidp; 381 struct vnode **vpp; 382{ 383 384 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 385} 386 387static int 388nullfs_checkexp(mp, nam, extflagsp, credanonp) 389 struct mount *mp; 390 struct sockaddr *nam; 391 int *extflagsp; 392 struct ucred **credanonp; 393{ 394 395 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 396 extflagsp, credanonp); 397} 398 399static int 400nullfs_vptofh(vp, fhp) 401 struct vnode *vp; 402 struct fid *fhp; 403{ 404 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 405} 406 407static int 408nullfs_extattrctl(mp, cmd, attrname, arg, p) 409 struct mount *mp; 410 int cmd; 411 const char *attrname; 412 caddr_t arg; 413 struct proc *p; 414{ 415 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, 416 arg, p); 417} 418 419 420static struct vfsops null_vfsops = { 421 nullfs_mount, 422 nullfs_start, 423 nullfs_unmount, 424 nullfs_root, 425 nullfs_quotactl, 426 nullfs_statfs, 427 nullfs_sync, 428 nullfs_vget, 429 nullfs_fhtovp, 430 nullfs_checkexp, 431 nullfs_vptofh, 432 nullfs_init, 433 nullfs_uninit, 434 nullfs_extattrctl, 435}; 436 437VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK); 438