null_vfsops.c revision 116271
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 116271 2003-06-12 20:48:38Z 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/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 <fs/nullfs/null.h> 58 59static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure"); 60 61static vfs_fhtovp_t nullfs_fhtovp; 62static vfs_checkexp_t nullfs_checkexp; 63static vfs_nmount_t nullfs_mount; 64static vfs_quotactl_t nullfs_quotactl; 65static vfs_root_t nullfs_root; 66static vfs_start_t nullfs_start; 67static vfs_sync_t nullfs_sync; 68static vfs_statfs_t nullfs_statfs; 69static vfs_unmount_t nullfs_unmount; 70static vfs_vget_t nullfs_vget; 71static vfs_vptofh_t nullfs_vptofh; 72static vfs_extattrctl_t nullfs_extattrctl; 73 74/* 75 * Mount null layer 76 */ 77static int 78nullfs_mount(mp, ndp, td) 79 struct mount *mp; 80 struct nameidata *ndp; 81 struct thread *td; 82{ 83 int error = 0; 84 struct vnode *lowerrootvp, *vp; 85 struct vnode *nullm_rootvp; 86 struct null_mount *xmp; 87 char *target; 88 size_t size; 89 int isvnunlocked = 0, len; 90 91 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 92 93 /* 94 * Update is a no-op 95 */ 96 if (mp->mnt_flag & MNT_UPDATE) { 97 return (EOPNOTSUPP); 98 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, td);*/ 99 } 100 101 /* 102 * Get argument 103 */ 104 error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len); 105 if (error || target[len - 1] != '\0') 106 return (EINVAL); 107 108 /* 109 * Unlock lower node to avoid deadlock. 110 * (XXX) VOP_ISLOCKED is needed? 111 */ 112 if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) && 113 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 114 VOP_UNLOCK(mp->mnt_vnodecovered, 0, td); 115 isvnunlocked = 1; 116 } 117 /* 118 * Find lower node 119 */ 120 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 121 UIO_SYSSPACE, target, td); 122 error = namei(ndp); 123 /* 124 * Re-lock vnode. 125 */ 126 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 127 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td); 128 129 if (error) 130 return (error); 131 NDFREE(ndp, NDF_ONLY_PNBUF); 132 133 /* 134 * Sanity check on lower vnode 135 */ 136 lowerrootvp = ndp->ni_vp; 137 138 vrele(ndp->ni_dvp); 139 ndp->ni_dvp = NULLVP; 140 141 /* 142 * Check multi null mount to avoid `lock against myself' panic. 143 */ 144 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 145 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 146 vput(lowerrootvp); 147 return (EDEADLK); 148 } 149 150 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 151 M_NULLFSMNT, M_WAITOK); /* XXX */ 152 153 /* 154 * Save reference to underlying FS 155 */ 156 xmp->nullm_vfs = lowerrootvp->v_mount; 157 158 /* 159 * Save reference. Each mount also holds 160 * a reference on the root vnode. 161 */ 162 error = null_nodeget(mp, lowerrootvp, &vp); 163 /* 164 * Make sure the node alias worked 165 */ 166 if (error) { 167 VOP_UNLOCK(vp, 0, td); 168 vrele(lowerrootvp); 169 free(xmp, M_NULLFSMNT); /* XXX */ 170 return (error); 171 } 172 173 /* 174 * Keep a held reference to the root vnode. 175 * It is vrele'd in nullfs_unmount. 176 */ 177 nullm_rootvp = vp; 178 nullm_rootvp->v_vflag |= VV_ROOT; 179 xmp->nullm_rootvp = nullm_rootvp; 180 181 /* 182 * Unlock the node (either the lower or the alias) 183 */ 184 VOP_UNLOCK(vp, 0, td); 185 186 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 187 mp->mnt_flag |= MNT_LOCAL; 188 mp->mnt_data = (qaddr_t) xmp; 189 vfs_getnewfsid(mp); 190 191 (void) copystr(target, mp->mnt_stat.f_mntfromname, 192 MNAMELEN - 1, &size); 193 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 194 (void)nullfs_statfs(mp, &mp->mnt_stat, td); 195 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 196 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 197 return (0); 198} 199 200/* 201 * VFS start. Nothing needed here - the start routine 202 * on the underlying filesystem will have been called 203 * when that filesystem was mounted. 204 */ 205static int 206nullfs_start(mp, flags, td) 207 struct mount *mp; 208 int flags; 209 struct thread *td; 210{ 211 return (0); 212 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */ 213} 214 215/* 216 * Free reference to null layer 217 */ 218static int 219nullfs_unmount(mp, mntflags, td) 220 struct mount *mp; 221 int mntflags; 222 struct thread *td; 223{ 224 void *mntdata; 225 int error; 226 int flags = 0; 227 228 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 229 230 if (mntflags & MNT_FORCE) 231 flags |= FORCECLOSE; 232 233 /* There is 1 extra root vnode reference (nullm_rootvp). */ 234 error = vflush(mp, 1, flags); 235 if (error) 236 return (error); 237 238 /* 239 * Finally, throw away the null_mount structure 240 */ 241 mntdata = mp->mnt_data; 242 mp->mnt_data = 0; 243 free(mntdata, M_NULLFSMNT); 244 return 0; 245} 246 247static int 248nullfs_root(mp, vpp) 249 struct mount *mp; 250 struct vnode **vpp; 251{ 252 struct thread *td = curthread; /* XXX */ 253 struct vnode *vp; 254 255 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 256 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 257 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 258 259 /* 260 * Return locked reference to root. 261 */ 262 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 263 VREF(vp); 264 265#ifdef NULLFS_DEBUG 266 if (VOP_ISLOCKED(vp, NULL)) { 267 Debugger("root vnode is locked.\n"); 268 vrele(vp); 269 return (EDEADLK); 270 } 271#endif 272 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 273 *vpp = vp; 274 return 0; 275} 276 277static int 278nullfs_quotactl(mp, cmd, uid, arg, td) 279 struct mount *mp; 280 int cmd; 281 uid_t uid; 282 caddr_t arg; 283 struct thread *td; 284{ 285 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); 286} 287 288static int 289nullfs_statfs(mp, sbp, td) 290 struct mount *mp; 291 struct statfs *sbp; 292 struct thread *td; 293{ 294 int error; 295 struct statfs mstat; 296 297 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 298 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 299 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 300 301 bzero(&mstat, sizeof(mstat)); 302 303 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); 304 if (error) 305 return (error); 306 307 /* now copy across the "interesting" information and fake the rest */ 308 sbp->f_type = mstat.f_type; 309 sbp->f_flags = mstat.f_flags; 310 sbp->f_bsize = mstat.f_bsize; 311 sbp->f_iosize = mstat.f_iosize; 312 sbp->f_blocks = mstat.f_blocks; 313 sbp->f_bfree = mstat.f_bfree; 314 sbp->f_bavail = mstat.f_bavail; 315 sbp->f_files = mstat.f_files; 316 sbp->f_ffree = mstat.f_ffree; 317 if (sbp != &mp->mnt_stat) { 318 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 319 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 320 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 321 } 322 return (0); 323} 324 325static int 326nullfs_sync(mp, waitfor, cred, td) 327 struct mount *mp; 328 int waitfor; 329 struct ucred *cred; 330 struct thread *td; 331{ 332 /* 333 * XXX - Assumes no data cached at null layer. 334 */ 335 return (0); 336} 337 338static int 339nullfs_vget(mp, ino, flags, vpp) 340 struct mount *mp; 341 ino_t ino; 342 int flags; 343 struct vnode **vpp; 344{ 345 int error; 346 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp); 347 if (error) 348 return (error); 349 350 return (null_nodeget(mp, *vpp, vpp)); 351} 352 353static int 354nullfs_fhtovp(mp, fidp, vpp) 355 struct mount *mp; 356 struct fid *fidp; 357 struct vnode **vpp; 358{ 359 int error; 360 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 361 if (error) 362 return (error); 363 364 return (null_nodeget(mp, *vpp, vpp)); 365} 366 367static int 368nullfs_checkexp(mp, nam, extflagsp, credanonp) 369 struct mount *mp; 370 struct sockaddr *nam; 371 int *extflagsp; 372 struct ucred **credanonp; 373{ 374 375 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 376 extflagsp, credanonp); 377} 378 379static int 380nullfs_vptofh(vp, fhp) 381 struct vnode *vp; 382 struct fid *fhp; 383{ 384 struct vnode *lvp; 385 386 lvp = NULLVPTOLOWERVP(vp); 387 return VFS_VPTOFH(lvp, fhp); 388} 389 390static int 391nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname, td) 392 struct mount *mp; 393 int cmd; 394 struct vnode *filename_vp; 395 int namespace; 396 const char *attrname; 397 struct thread *td; 398{ 399 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp, 400 namespace, attrname, td); 401} 402 403 404static struct vfsops null_vfsops = { 405 .vfs_checkexp = nullfs_checkexp, 406 .vfs_extattrctl = nullfs_extattrctl, 407 .vfs_fhtovp = nullfs_fhtovp, 408 .vfs_init = nullfs_init, 409 .vfs_nmount = nullfs_mount, 410 .vfs_quotactl = nullfs_quotactl, 411 .vfs_root = nullfs_root, 412 .vfs_start = nullfs_start, 413 .vfs_statfs = nullfs_statfs, 414 .vfs_sync = nullfs_sync, 415 .vfs_uninit = nullfs_uninit, 416 .vfs_unmount = nullfs_unmount, 417 .vfs_vget = nullfs_vget, 418 .vfs_vptofh = nullfs_vptofh, 419}; 420 421VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK); 422