null_vfsops.c revision 56272
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 56272 2000-01-19 06:07:34Z rwatson $ 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#include <vm/vm_zone.h> 57 58static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure"); 59 60static int nullfs_fhtovp __P((struct mount *mp, struct fid *fidp, 61 struct vnode **vpp)); 62static int nullfs_checkexp __P((struct mount *mp, struct sockaddr *nam, 63 int *extflagsp, struct ucred **credanonp)); 64static int nullfs_mount __P((struct mount *mp, char *path, caddr_t data, 65 struct nameidata *ndp, struct proc *p)); 66static int nullfs_quotactl __P((struct mount *mp, int cmd, uid_t uid, 67 caddr_t arg, struct proc *p)); 68static int nullfs_root __P((struct mount *mp, struct vnode **vpp)); 69static int nullfs_start __P((struct mount *mp, int flags, struct proc *p)); 70static int nullfs_statfs __P((struct mount *mp, struct statfs *sbp, 71 struct proc *p)); 72static int nullfs_sync __P((struct mount *mp, int waitfor, 73 struct ucred *cred, struct proc *p)); 74static int nullfs_unmount __P((struct mount *mp, int mntflags, 75 struct proc *p)); 76static int nullfs_vget __P((struct mount *mp, ino_t ino, 77 struct vnode **vpp)); 78static int nullfs_vptofh __P((struct vnode *vp, struct fid *fhp)); 79 80/* 81 * Mount null layer 82 */ 83static int 84nullfs_mount(mp, path, data, ndp, p) 85 struct mount *mp; 86 char *path; 87 caddr_t data; 88 struct nameidata *ndp; 89 struct proc *p; 90{ 91 int error = 0; 92 struct null_args args; 93 struct vnode *lowerrootvp, *vp; 94 struct vnode *nullm_rootvp; 95 struct null_mount *xmp; 96 u_int size; 97 int isvnunlocked = 0; 98 99#ifdef DEBUG 100 printf("nullfs_mount(mp = %p)\n", (void *)mp); 101#endif 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, p);*/ 109 } 110 111 /* 112 * Get argument 113 */ 114 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 115 if (error) 116 return (error); 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, p); 125 isvnunlocked = 1; 126 } 127 /* 128 * Find lower node 129 */ 130 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 131 UIO_USERSPACE, args.target, p); 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, p); 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#ifdef DEBUG 156 printf("nullfs_mount: multi null mount?\n"); 157#endif 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(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 200 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); 201 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 202 &size); 203 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 204 (void)nullfs_statfs(mp, &mp->mnt_stat, p); 205#ifdef DEBUG 206 printf("nullfs_mount: lower %s, alias at %s\n", 207 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 208#endif 209 return (0); 210} 211 212/* 213 * VFS start. Nothing needed here - the start routine 214 * on the underlying filesystem will have been called 215 * when that filesystem was mounted. 216 */ 217static int 218nullfs_start(mp, flags, p) 219 struct mount *mp; 220 int flags; 221 struct proc *p; 222{ 223 return (0); 224 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */ 225} 226 227/* 228 * Free reference to null layer 229 */ 230static int 231nullfs_unmount(mp, mntflags, p) 232 struct mount *mp; 233 int mntflags; 234 struct proc *p; 235{ 236 struct vnode *nullm_rootvp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 237 int error; 238 int flags = 0; 239 240#ifdef DEBUG 241 printf("nullfs_unmount(mp = %p)\n", (void *)mp); 242#endif 243 244 if (mntflags & MNT_FORCE) 245 flags |= FORCECLOSE; 246 247 /* 248 * Clear out buffer cache. I don't think we 249 * ever get anything cached at this level at the 250 * moment, but who knows... 251 */ 252#if 0 253 mntflushbuf(mp, 0); 254 if (mntinvalbuf(mp, 1)) 255 return (EBUSY); 256#endif 257 if (nullm_rootvp->v_usecount > 1) 258 return (EBUSY); 259 error = vflush(mp, nullm_rootvp, flags); 260 if (error) 261 return (error); 262 263#ifdef DEBUG 264 vprint("alias root of lower", nullm_rootvp); 265#endif 266 /* 267 * Release reference on underlying root vnode 268 */ 269 vrele(nullm_rootvp); 270 /* 271 * And blow it away for future re-use 272 */ 273 vgone(nullm_rootvp); 274 /* 275 * Finally, throw away the null_mount structure 276 */ 277 free(mp->mnt_data, M_NULLFSMNT); /* XXX */ 278 mp->mnt_data = 0; 279 return 0; 280} 281 282static int 283nullfs_root(mp, vpp) 284 struct mount *mp; 285 struct vnode **vpp; 286{ 287 struct proc *p = curproc; /* XXX */ 288 struct vnode *vp; 289 290#ifdef DEBUG 291 printf("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 292 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 293 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 294#endif 295 296 /* 297 * Return locked reference to root. 298 */ 299 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 300 VREF(vp); 301 if (VOP_ISLOCKED(vp, NULL)) { 302 /* 303 * XXX 304 * Should we check type of node? 305 */ 306#ifdef DEBUG 307 printf("nullfs_root: multi null mount?\n"); 308#endif 309 vrele(vp); 310 return (EDEADLK); 311 } else 312 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 313 *vpp = vp; 314 return 0; 315} 316 317static int 318nullfs_quotactl(mp, cmd, uid, arg, p) 319 struct mount *mp; 320 int cmd; 321 uid_t uid; 322 caddr_t arg; 323 struct proc *p; 324{ 325 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p); 326} 327 328static int 329nullfs_statfs(mp, sbp, p) 330 struct mount *mp; 331 struct statfs *sbp; 332 struct proc *p; 333{ 334 int error; 335 struct statfs mstat; 336 337#ifdef DEBUG 338 printf("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 339 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 340 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 341#endif 342 343 bzero(&mstat, sizeof(mstat)); 344 345 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p); 346 if (error) 347 return (error); 348 349 /* now copy across the "interesting" information and fake the rest */ 350 sbp->f_type = mstat.f_type; 351 sbp->f_flags = mstat.f_flags; 352 sbp->f_bsize = mstat.f_bsize; 353 sbp->f_iosize = mstat.f_iosize; 354 sbp->f_blocks = mstat.f_blocks; 355 sbp->f_bfree = mstat.f_bfree; 356 sbp->f_bavail = mstat.f_bavail; 357 sbp->f_files = mstat.f_files; 358 sbp->f_ffree = mstat.f_ffree; 359 if (sbp != &mp->mnt_stat) { 360 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 361 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 362 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 363 } 364 return (0); 365} 366 367static int 368nullfs_sync(mp, waitfor, cred, p) 369 struct mount *mp; 370 int waitfor; 371 struct ucred *cred; 372 struct proc *p; 373{ 374 /* 375 * XXX - Assumes no data cached at null layer. 376 */ 377 return (0); 378} 379 380static int 381nullfs_vget(mp, ino, vpp) 382 struct mount *mp; 383 ino_t ino; 384 struct vnode **vpp; 385{ 386 387 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 388} 389 390static int 391nullfs_fhtovp(mp, fidp, vpp) 392 struct mount *mp; 393 struct fid *fidp; 394 struct vnode **vpp; 395{ 396 397 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 398} 399 400static int 401nullfs_checkexp(mp, nam, extflagsp, credanonp) 402 struct mount *mp; 403 struct sockaddr *nam; 404 int *extflagsp; 405 struct ucred **credanonp; 406{ 407 408 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 409 extflagsp, credanonp); 410} 411 412static int 413nullfs_vptofh(vp, fhp) 414 struct vnode *vp; 415 struct fid *fhp; 416{ 417 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 418} 419 420static int 421nullfs_extattrctl(mp, cmd, attrname, arg, p) 422 struct mount *mp; 423 int cmd; 424 const char *attrname; 425 caddr_t arg; 426 struct proc *p; 427{ 428 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, 429 arg, p); 430} 431 432 433static struct vfsops null_vfsops = { 434 nullfs_mount, 435 nullfs_start, 436 nullfs_unmount, 437 nullfs_root, 438 nullfs_quotactl, 439 nullfs_statfs, 440 nullfs_sync, 441 nullfs_vget, 442 nullfs_fhtovp, 443 nullfs_checkexp, 444 nullfs_vptofh, 445 nullfs_init, 446 vfs_stduninit, 447 nullfs_extattrctl, 448}; 449 450VFS_SET(null_vfsops, null, VFCF_LOOPBACK); 451