null_vfsops.c revision 67439
181656Sache/* 281656Sache * Copyright (c) 1992, 1993, 1995 381656Sache * The Regents of the University of California. All rights reserved. 481656Sache * 581656Sache * This code is derived from software donated to Berkeley by 681656Sache * Jan-Simon Pendry. 781656Sache * 881656Sache * Redistribution and use in source and binary forms, with or without 981656Sache * modification, are permitted provided that the following conditions 1081656Sache * are met: 1181656Sache * 1. Redistributions of source code must retain the above copyright 1281656Sache * notice, this list of conditions and the following disclaimer. 13110994Sdes * 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 67439 2000-10-22 15:40:22Z 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); 76static int nullfs_extattrctl(struct mount *mp, int cmd, 77 const char *attrname, caddr_t arg, struct proc *p); 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 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 99 100 /* 101 * Update is a no-op 102 */ 103 if (mp->mnt_flag & MNT_UPDATE) { 104 return (EOPNOTSUPP); 105 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/ 106 } 107 108 /* 109 * Get argument 110 */ 111 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 112 if (error) 113 return (error); 114 115 /* 116 * Unlock lower node to avoid deadlock. 117 * (XXX) VOP_ISLOCKED is needed? 118 */ 119 if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) && 120 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 121 VOP_UNLOCK(mp->mnt_vnodecovered, 0, p); 122 isvnunlocked = 1; 123 } 124 /* 125 * Find lower node 126 */ 127 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 128 UIO_USERSPACE, args.target, p); 129 error = namei(ndp); 130 /* 131 * Re-lock vnode. 132 */ 133 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 134 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, p); 135 136 if (error) 137 return (error); 138 NDFREE(ndp, NDF_ONLY_PNBUF); 139 140 /* 141 * Sanity check on lower vnode 142 */ 143 lowerrootvp = ndp->ni_vp; 144 145 vrele(ndp->ni_dvp); 146 ndp->ni_dvp = NULLVP; 147 148 /* 149 * Check multi null mount to avoid `lock against myself' panic. 150 */ 151 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 152 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 153 VOP_UNLOCK(lowerrootvp, 0, p); 154 return (EDEADLK); 155 } 156 157 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 158 M_NULLFSMNT, M_WAITOK); /* XXX */ 159 160 /* 161 * Save reference to underlying FS 162 */ 163 xmp->nullm_vfs = lowerrootvp->v_mount; 164 165 /* 166 * Save reference. Each mount also holds 167 * a reference on the root vnode. 168 */ 169 error = null_node_create(mp, lowerrootvp, &vp); 170 /* 171 * Unlock the node (either the lower or the alias) 172 */ 173 VOP_UNLOCK(vp, 0, p); 174 /* 175 * Make sure the node alias worked 176 */ 177 if (error) { 178 vrele(lowerrootvp); 179 free(xmp, M_NULLFSMNT); /* XXX */ 180 return (error); 181 } 182 183 /* 184 * Keep a held reference to the root vnode. 185 * It is vrele'd in nullfs_unmount. 186 */ 187 nullm_rootvp = vp; 188 nullm_rootvp->v_flag |= VROOT; 189 xmp->nullm_rootvp = nullm_rootvp; 190 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 191 mp->mnt_flag |= MNT_LOCAL; 192 mp->mnt_data = (qaddr_t) xmp; 193 vfs_getnewfsid(mp); 194 195 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 196 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); 197 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 198 &size); 199 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 200 (void)nullfs_statfs(mp, &mp->mnt_stat, p); 201 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 202 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 203 return (0); 204} 205 206/* 207 * VFS start. Nothing needed here - the start routine 208 * on the underlying filesystem will have been called 209 * when that filesystem was mounted. 210 */ 211static int 212nullfs_start(mp, flags, p) 213 struct mount *mp; 214 int flags; 215 struct proc *p; 216{ 217 return (0); 218 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */ 219} 220 221/* 222 * Free reference to null layer 223 */ 224static int 225nullfs_unmount(mp, mntflags, p) 226 struct mount *mp; 227 int mntflags; 228 struct proc *p; 229{ 230 struct vnode *vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 231 void *mntdata; 232 int error; 233 int flags = 0; 234 235 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 236 237 if (mntflags & MNT_FORCE) 238 flags |= FORCECLOSE; 239 240 error = VFS_ROOT(mp, &vp); 241 if (error) 242 return (error); 243 if (vp->v_usecount > 2) { 244 NULLFSDEBUG("nullfs_unmount: rootvp is busy(%d)\n", 245 vp->v_usecount); 246 vput(vp); 247 return (EBUSY); 248 } 249 error = vflush(mp, vp, flags); 250 if (error) 251 return (error); 252 253#ifdef NULLFS_DEBUG 254 vprint("alias root of lower", vp); 255#endif 256 vput(vp); 257 /* 258 * Release reference on underlying root vnode 259 */ 260 vrele(vp); 261 /* 262 * And blow it away for future re-use 263 */ 264 vgone(vp); 265 /* 266 * Finally, throw away the null_mount structure 267 */ 268 mntdata = mp->mnt_data; 269 mp->mnt_data = 0; 270 free(mntdata, M_NULLFSMNT); 271 return 0; 272} 273 274static int 275nullfs_root(mp, vpp) 276 struct mount *mp; 277 struct vnode **vpp; 278{ 279 struct proc *p = curproc; /* XXX */ 280 struct vnode *vp; 281 282 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 283 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 284 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 285 286 /* 287 * Return locked reference to root. 288 */ 289 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 290 VREF(vp); 291 292#ifdef NULLFS_DEBUG 293 if (VOP_ISLOCKED(vp, NULL)) { 294 Debugger("root vnode is locked.\n"); 295 vrele(vp); 296 return (EDEADLK); 297 } 298#endif 299 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 300 *vpp = vp; 301 return 0; 302} 303 304static int 305nullfs_quotactl(mp, cmd, uid, arg, p) 306 struct mount *mp; 307 int cmd; 308 uid_t uid; 309 caddr_t arg; 310 struct proc *p; 311{ 312 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p); 313} 314 315static int 316nullfs_statfs(mp, sbp, p) 317 struct mount *mp; 318 struct statfs *sbp; 319 struct proc *p; 320{ 321 int error; 322 struct statfs mstat; 323 324 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 325 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 326 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 327 328 bzero(&mstat, sizeof(mstat)); 329 330 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p); 331 if (error) 332 return (error); 333 334 /* now copy across the "interesting" information and fake the rest */ 335 sbp->f_type = mstat.f_type; 336 sbp->f_flags = mstat.f_flags; 337 sbp->f_bsize = mstat.f_bsize; 338 sbp->f_iosize = mstat.f_iosize; 339 sbp->f_blocks = mstat.f_blocks; 340 sbp->f_bfree = mstat.f_bfree; 341 sbp->f_bavail = mstat.f_bavail; 342 sbp->f_files = mstat.f_files; 343 sbp->f_ffree = mstat.f_ffree; 344 if (sbp != &mp->mnt_stat) { 345 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 346 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 347 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 348 } 349 return (0); 350} 351 352static int 353nullfs_sync(mp, waitfor, cred, p) 354 struct mount *mp; 355 int waitfor; 356 struct ucred *cred; 357 struct proc *p; 358{ 359 /* 360 * XXX - Assumes no data cached at null layer. 361 */ 362 return (0); 363} 364 365static int 366nullfs_vget(mp, ino, vpp) 367 struct mount *mp; 368 ino_t ino; 369 struct vnode **vpp; 370{ 371 int error; 372 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 373 if (error) 374 return (error); 375 376 return (null_node_create(mp, *vpp, vpp)); 377} 378 379static int 380nullfs_fhtovp(mp, fidp, vpp) 381 struct mount *mp; 382 struct fid *fidp; 383 struct vnode **vpp; 384{ 385 int error; 386 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 387 if (error) 388 return (error); 389 390 return (null_node_create(mp, *vpp, vpp)); 391} 392 393static int 394nullfs_checkexp(mp, nam, extflagsp, credanonp) 395 struct mount *mp; 396 struct sockaddr *nam; 397 int *extflagsp; 398 struct ucred **credanonp; 399{ 400 401 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 402 extflagsp, credanonp); 403} 404 405static int 406nullfs_vptofh(vp, fhp) 407 struct vnode *vp; 408 struct fid *fhp; 409{ 410 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 411} 412 413static int 414nullfs_extattrctl(mp, cmd, attrname, arg, p) 415 struct mount *mp; 416 int cmd; 417 const char *attrname; 418 caddr_t arg; 419 struct proc *p; 420{ 421 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, 422 arg, p); 423} 424 425 426static struct vfsops null_vfsops = { 427 nullfs_mount, 428 nullfs_start, 429 nullfs_unmount, 430 nullfs_root, 431 nullfs_quotactl, 432 nullfs_statfs, 433 nullfs_sync, 434 nullfs_vget, 435 nullfs_fhtovp, 436 nullfs_checkexp, 437 nullfs_vptofh, 438 nullfs_init, 439 nullfs_uninit, 440 nullfs_extattrctl, 441}; 442 443VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK); 444