null_vfsops.c revision 109623
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 109623 2003-01-21 08:56:16Z alfred $ 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 int nullfs_fhtovp(struct mount *mp, struct fid *fidp, 62 struct vnode **vpp); 63static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam, 64 int *extflagsp, struct ucred **credanonp); 65static int nullfs_mount(struct mount *mp, struct nameidata *ndp, 66 struct thread *td); 67static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, 68 caddr_t arg, struct thread *td); 69static int nullfs_root(struct mount *mp, struct vnode **vpp); 70static int nullfs_start(struct mount *mp, int flags, struct thread *td); 71static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 72 struct thread *td); 73static int nullfs_sync(struct mount *mp, int waitfor, 74 struct ucred *cred, struct thread *td); 75static int nullfs_unmount(struct mount *mp, int mntflags, struct thread *td); 76static int nullfs_vget(struct mount *mp, ino_t ino, int flags, 77 struct vnode **vpp); 78static int nullfs_vptofh(struct vnode *vp, struct fid *fhp); 79static int nullfs_extattrctl(struct mount *mp, int cmd, 80 struct vnode *filename_vp, 81 int namespace, const char *attrname, 82 struct thread *td); 83 84/* 85 * Mount null layer 86 */ 87static int 88nullfs_mount(mp, ndp, td) 89 struct mount *mp; 90 struct nameidata *ndp; 91 struct thread *td; 92{ 93 int error = 0; 94 struct vnode *lowerrootvp, *vp; 95 struct vnode *nullm_rootvp; 96 struct null_mount *xmp; 97 char *target; 98 size_t size; 99 int isvnunlocked = 0, len; 100 101 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 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, td);*/ 109 } 110 111 /* 112 * Get argument 113 */ 114 error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len); 115 if (error || target[len - 1] != '\0') 116 return (EINVAL); 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, td); 125 isvnunlocked = 1; 126 } 127 /* 128 * Find lower node 129 */ 130 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 131 UIO_SYSSPACE, target, td); 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, td); 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 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 156 vput(lowerrootvp); 157 return (EDEADLK); 158 } 159 160 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 161 M_NULLFSMNT, 0); /* 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_nodeget(mp, lowerrootvp, &vp); 173 /* 174 * Make sure the node alias worked 175 */ 176 if (error) { 177 VOP_UNLOCK(vp, 0, td); 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_vflag |= VV_ROOT; 189 xmp->nullm_rootvp = nullm_rootvp; 190 191 /* 192 * Unlock the node (either the lower or the alias) 193 */ 194 VOP_UNLOCK(vp, 0, td); 195 196 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 197 mp->mnt_flag |= MNT_LOCAL; 198 mp->mnt_data = (qaddr_t) xmp; 199 vfs_getnewfsid(mp); 200 201 (void) copystr(target, mp->mnt_stat.f_mntfromname, 202 MNAMELEN - 1, &size); 203 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 204 (void)nullfs_statfs(mp, &mp->mnt_stat, td); 205 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 206 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 207 return (0); 208} 209 210/* 211 * VFS start. Nothing needed here - the start routine 212 * on the underlying filesystem will have been called 213 * when that filesystem was mounted. 214 */ 215static int 216nullfs_start(mp, flags, td) 217 struct mount *mp; 218 int flags; 219 struct thread *td; 220{ 221 return (0); 222 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */ 223} 224 225/* 226 * Free reference to null layer 227 */ 228static int 229nullfs_unmount(mp, mntflags, td) 230 struct mount *mp; 231 int mntflags; 232 struct thread *td; 233{ 234 void *mntdata; 235 int error; 236 int flags = 0; 237 238 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 239 240 if (mntflags & MNT_FORCE) 241 flags |= FORCECLOSE; 242 243 /* There is 1 extra root vnode reference (nullm_rootvp). */ 244 error = vflush(mp, 1, flags); 245 if (error) 246 return (error); 247 248 /* 249 * Finally, throw away the null_mount structure 250 */ 251 mntdata = mp->mnt_data; 252 mp->mnt_data = 0; 253 free(mntdata, M_NULLFSMNT); 254 return 0; 255} 256 257static int 258nullfs_root(mp, vpp) 259 struct mount *mp; 260 struct vnode **vpp; 261{ 262 struct thread *td = curthread; /* XXX */ 263 struct vnode *vp; 264 265 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 266 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 267 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 268 269 /* 270 * Return locked reference to root. 271 */ 272 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 273 VREF(vp); 274 275#ifdef NULLFS_DEBUG 276 if (VOP_ISLOCKED(vp, NULL)) { 277 Debugger("root vnode is locked.\n"); 278 vrele(vp); 279 return (EDEADLK); 280 } 281#endif 282 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 283 *vpp = vp; 284 return 0; 285} 286 287static int 288nullfs_quotactl(mp, cmd, uid, arg, td) 289 struct mount *mp; 290 int cmd; 291 uid_t uid; 292 caddr_t arg; 293 struct thread *td; 294{ 295 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); 296} 297 298static int 299nullfs_statfs(mp, sbp, td) 300 struct mount *mp; 301 struct statfs *sbp; 302 struct thread *td; 303{ 304 int error; 305 struct statfs mstat; 306 307 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 308 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 309 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 310 311 bzero(&mstat, sizeof(mstat)); 312 313 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); 314 if (error) 315 return (error); 316 317 /* now copy across the "interesting" information and fake the rest */ 318 sbp->f_type = mstat.f_type; 319 sbp->f_flags = mstat.f_flags; 320 sbp->f_bsize = mstat.f_bsize; 321 sbp->f_iosize = mstat.f_iosize; 322 sbp->f_blocks = mstat.f_blocks; 323 sbp->f_bfree = mstat.f_bfree; 324 sbp->f_bavail = mstat.f_bavail; 325 sbp->f_files = mstat.f_files; 326 sbp->f_ffree = mstat.f_ffree; 327 if (sbp != &mp->mnt_stat) { 328 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 329 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 330 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 331 } 332 return (0); 333} 334 335static int 336nullfs_sync(mp, waitfor, cred, td) 337 struct mount *mp; 338 int waitfor; 339 struct ucred *cred; 340 struct thread *td; 341{ 342 /* 343 * XXX - Assumes no data cached at null layer. 344 */ 345 return (0); 346} 347 348static int 349nullfs_vget(mp, ino, flags, vpp) 350 struct mount *mp; 351 ino_t ino; 352 int flags; 353 struct vnode **vpp; 354{ 355 int error; 356 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp); 357 if (error) 358 return (error); 359 360 return (null_nodeget(mp, *vpp, vpp)); 361} 362 363static int 364nullfs_fhtovp(mp, fidp, vpp) 365 struct mount *mp; 366 struct fid *fidp; 367 struct vnode **vpp; 368{ 369 int error; 370 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 371 if (error) 372 return (error); 373 374 return (null_nodeget(mp, *vpp, vpp)); 375} 376 377static int 378nullfs_checkexp(mp, nam, extflagsp, credanonp) 379 struct mount *mp; 380 struct sockaddr *nam; 381 int *extflagsp; 382 struct ucred **credanonp; 383{ 384 385 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 386 extflagsp, credanonp); 387} 388 389static int 390nullfs_vptofh(vp, fhp) 391 struct vnode *vp; 392 struct fid *fhp; 393{ 394 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 395} 396 397static int 398nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname, td) 399 struct mount *mp; 400 int cmd; 401 struct vnode *filename_vp; 402 int namespace; 403 const char *attrname; 404 struct thread *td; 405{ 406 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp, 407 namespace, attrname, td); 408} 409 410 411static struct vfsops null_vfsops = { 412 NULL, 413 nullfs_start, 414 nullfs_unmount, 415 nullfs_root, 416 nullfs_quotactl, 417 nullfs_statfs, 418 nullfs_sync, 419 nullfs_vget, 420 nullfs_fhtovp, 421 nullfs_checkexp, 422 nullfs_vptofh, 423 nullfs_init, 424 nullfs_uninit, 425 nullfs_extattrctl, 426 nullfs_mount, 427}; 428 429VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK); 430