null_vfsops.c revision 59794
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 59794 2000-04-30 18:52:11Z phk $ 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 __P((struct mount *mp, struct fid *fidp, 60 struct vnode **vpp)); 61static int nullfs_checkexp __P((struct mount *mp, struct sockaddr *nam, 62 int *extflagsp, struct ucred **credanonp)); 63static int nullfs_mount __P((struct mount *mp, char *path, caddr_t data, 64 struct nameidata *ndp, struct proc *p)); 65static int nullfs_quotactl __P((struct mount *mp, int cmd, uid_t uid, 66 caddr_t arg, struct proc *p)); 67static int nullfs_root __P((struct mount *mp, struct vnode **vpp)); 68static int nullfs_start __P((struct mount *mp, int flags, struct proc *p)); 69static int nullfs_statfs __P((struct mount *mp, struct statfs *sbp, 70 struct proc *p)); 71static int nullfs_sync __P((struct mount *mp, int waitfor, 72 struct ucred *cred, struct proc *p)); 73static int nullfs_unmount __P((struct mount *mp, int mntflags, 74 struct proc *p)); 75static int nullfs_vget __P((struct mount *mp, ino_t ino, 76 struct vnode **vpp)); 77static int nullfs_vptofh __P((struct vnode *vp, struct fid *fhp)); 78 79/* 80 * Mount null layer 81 */ 82static int 83nullfs_mount(mp, path, data, ndp, p) 84 struct mount *mp; 85 char *path; 86 caddr_t data; 87 struct nameidata *ndp; 88 struct proc *p; 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#ifdef DEBUG 99 printf("nullfs_mount(mp = %p)\n", (void *)mp); 100#endif 101 102 /* 103 * Update is a no-op 104 */ 105 if (mp->mnt_flag & MNT_UPDATE) { 106 return (EOPNOTSUPP); 107 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/ 108 } 109 110 /* 111 * Get argument 112 */ 113 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 114 if (error) 115 return (error); 116 117 /* 118 * Unlock lower node to avoid deadlock. 119 * (XXX) VOP_ISLOCKED is needed? 120 */ 121 if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) && 122 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 123 VOP_UNLOCK(mp->mnt_vnodecovered, 0, p); 124 isvnunlocked = 1; 125 } 126 /* 127 * Find lower node 128 */ 129 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 130 UIO_USERSPACE, args.target, p); 131 error = namei(ndp); 132 /* 133 * Re-lock vnode. 134 */ 135 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 136 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, p); 137 138 if (error) 139 return (error); 140 NDFREE(ndp, NDF_ONLY_PNBUF); 141 142 /* 143 * Sanity check on lower vnode 144 */ 145 lowerrootvp = ndp->ni_vp; 146 147 vrele(ndp->ni_dvp); 148 ndp->ni_dvp = NULLVP; 149 150 /* 151 * Check multi null mount to avoid `lock against myself' panic. 152 */ 153 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 154#ifdef DEBUG 155 printf("nullfs_mount: multi null mount?\n"); 156#endif 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_node_create(mp, lowerrootvp, &vp); 173 /* 174 * Unlock the node (either the lower or the alias) 175 */ 176 VOP_UNLOCK(vp, 0, p); 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 nullm_rootvp = vp; 191 nullm_rootvp->v_flag |= VROOT; 192 xmp->nullm_rootvp = nullm_rootvp; 193 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 194 mp->mnt_flag |= MNT_LOCAL; 195 mp->mnt_data = (qaddr_t) xmp; 196 vfs_getnewfsid(mp); 197 198 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 199 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); 200 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 201 &size); 202 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 203 (void)nullfs_statfs(mp, &mp->mnt_stat, p); 204#ifdef DEBUG 205 printf("nullfs_mount: lower %s, alias at %s\n", 206 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 207#endif 208 return (0); 209} 210 211/* 212 * VFS start. Nothing needed here - the start routine 213 * on the underlying filesystem will have been called 214 * when that filesystem was mounted. 215 */ 216static int 217nullfs_start(mp, flags, p) 218 struct mount *mp; 219 int flags; 220 struct proc *p; 221{ 222 return (0); 223 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */ 224} 225 226/* 227 * Free reference to null layer 228 */ 229static int 230nullfs_unmount(mp, mntflags, p) 231 struct mount *mp; 232 int mntflags; 233 struct proc *p; 234{ 235 struct vnode *nullm_rootvp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 236 int error; 237 int flags = 0; 238 239#ifdef DEBUG 240 printf("nullfs_unmount(mp = %p)\n", (void *)mp); 241#endif 242 243 if (mntflags & MNT_FORCE) 244 flags |= FORCECLOSE; 245 246 /* 247 * Clear out buffer cache. I don't think we 248 * ever get anything cached at this level at the 249 * moment, but who knows... 250 */ 251#if 0 252 mntflushbuf(mp, 0); 253 if (mntinvalbuf(mp, 1)) 254 return (EBUSY); 255#endif 256 if (nullm_rootvp->v_usecount > 1) 257 return (EBUSY); 258 error = vflush(mp, nullm_rootvp, flags); 259 if (error) 260 return (error); 261 262#ifdef DEBUG 263 vprint("alias root of lower", nullm_rootvp); 264#endif 265 /* 266 * Release reference on underlying root vnode 267 */ 268 vrele(nullm_rootvp); 269 /* 270 * And blow it away for future re-use 271 */ 272 vgone(nullm_rootvp); 273 /* 274 * Finally, throw away the null_mount structure 275 */ 276 free(mp->mnt_data, M_NULLFSMNT); /* XXX */ 277 mp->mnt_data = 0; 278 return 0; 279} 280 281static int 282nullfs_root(mp, vpp) 283 struct mount *mp; 284 struct vnode **vpp; 285{ 286 struct proc *p = curproc; /* XXX */ 287 struct vnode *vp; 288 289#ifdef DEBUG 290 printf("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 291 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 292 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 293#endif 294 295 /* 296 * Return locked reference to root. 297 */ 298 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 299 VREF(vp); 300 if (VOP_ISLOCKED(vp, NULL)) { 301 /* 302 * XXX 303 * Should we check type of node? 304 */ 305#ifdef DEBUG 306 printf("nullfs_root: multi null mount?\n"); 307#endif 308 vrele(vp); 309 return (EDEADLK); 310 } else 311 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 312 *vpp = vp; 313 return 0; 314} 315 316static int 317nullfs_quotactl(mp, cmd, uid, arg, p) 318 struct mount *mp; 319 int cmd; 320 uid_t uid; 321 caddr_t arg; 322 struct proc *p; 323{ 324 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p); 325} 326 327static int 328nullfs_statfs(mp, sbp, p) 329 struct mount *mp; 330 struct statfs *sbp; 331 struct proc *p; 332{ 333 int error; 334 struct statfs mstat; 335 336#ifdef DEBUG 337 printf("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 338 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 339 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 340#endif 341 342 bzero(&mstat, sizeof(mstat)); 343 344 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p); 345 if (error) 346 return (error); 347 348 /* now copy across the "interesting" information and fake the rest */ 349 sbp->f_type = mstat.f_type; 350 sbp->f_flags = mstat.f_flags; 351 sbp->f_bsize = mstat.f_bsize; 352 sbp->f_iosize = mstat.f_iosize; 353 sbp->f_blocks = mstat.f_blocks; 354 sbp->f_bfree = mstat.f_bfree; 355 sbp->f_bavail = mstat.f_bavail; 356 sbp->f_files = mstat.f_files; 357 sbp->f_ffree = mstat.f_ffree; 358 if (sbp != &mp->mnt_stat) { 359 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 360 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 361 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 362 } 363 return (0); 364} 365 366static int 367nullfs_sync(mp, waitfor, cred, p) 368 struct mount *mp; 369 int waitfor; 370 struct ucred *cred; 371 struct proc *p; 372{ 373 /* 374 * XXX - Assumes no data cached at null layer. 375 */ 376 return (0); 377} 378 379static int 380nullfs_vget(mp, ino, vpp) 381 struct mount *mp; 382 ino_t ino; 383 struct vnode **vpp; 384{ 385 386 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 387} 388 389static int 390nullfs_fhtovp(mp, fidp, vpp) 391 struct mount *mp; 392 struct fid *fidp; 393 struct vnode **vpp; 394{ 395 396 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 397} 398 399static int 400nullfs_checkexp(mp, nam, extflagsp, credanonp) 401 struct mount *mp; 402 struct sockaddr *nam; 403 int *extflagsp; 404 struct ucred **credanonp; 405{ 406 407 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 408 extflagsp, credanonp); 409} 410 411static int 412nullfs_vptofh(vp, fhp) 413 struct vnode *vp; 414 struct fid *fhp; 415{ 416 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 417} 418 419static int 420nullfs_extattrctl(mp, cmd, attrname, arg, p) 421 struct mount *mp; 422 int cmd; 423 const char *attrname; 424 caddr_t arg; 425 struct proc *p; 426{ 427 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, 428 arg, p); 429} 430 431 432static struct vfsops null_vfsops = { 433 nullfs_mount, 434 nullfs_start, 435 nullfs_unmount, 436 nullfs_root, 437 nullfs_quotactl, 438 nullfs_statfs, 439 nullfs_sync, 440 nullfs_vget, 441 nullfs_fhtovp, 442 nullfs_checkexp, 443 nullfs_vptofh, 444 nullfs_init, 445 vfs_stduninit, 446 nullfs_extattrctl, 447}; 448 449VFS_SET(null_vfsops, null, VFCF_LOOPBACK); 450