null_vfsops.c revision 92462
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 92462 2002-03-17 01:25:47Z mckusick $ 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, char *path, caddr_t data, 66 struct nameidata *ndp, 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, path, data, ndp, td) 89 struct mount *mp; 90 char *path; 91 caddr_t data; 92 struct nameidata *ndp; 93 struct thread *td; 94{ 95 int error = 0; 96 struct null_args args; 97 struct vnode *lowerrootvp, *vp; 98 struct vnode *nullm_rootvp; 99 struct null_mount *xmp; 100 size_t size; 101 int isvnunlocked = 0; 102 103 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 104 105 /* 106 * Update is a no-op 107 */ 108 if (mp->mnt_flag & MNT_UPDATE) { 109 return (EOPNOTSUPP); 110 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, td);*/ 111 } 112 113 /* 114 * Get argument 115 */ 116 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 117 if (error) 118 return (error); 119 120 /* 121 * Unlock lower node to avoid deadlock. 122 * (XXX) VOP_ISLOCKED is needed? 123 */ 124 if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) && 125 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 126 VOP_UNLOCK(mp->mnt_vnodecovered, 0, td); 127 isvnunlocked = 1; 128 } 129 /* 130 * Find lower node 131 */ 132 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 133 UIO_USERSPACE, args.target, td); 134 error = namei(ndp); 135 /* 136 * Re-lock vnode. 137 */ 138 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 139 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td); 140 141 if (error) 142 return (error); 143 NDFREE(ndp, NDF_ONLY_PNBUF); 144 145 /* 146 * Sanity check on lower vnode 147 */ 148 lowerrootvp = ndp->ni_vp; 149 150 vrele(ndp->ni_dvp); 151 ndp->ni_dvp = NULLVP; 152 153 /* 154 * Check multi null mount to avoid `lock against myself' panic. 155 */ 156 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 157 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 158 vput(lowerrootvp); 159 return (EDEADLK); 160 } 161 162 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 163 M_NULLFSMNT, M_WAITOK); /* XXX */ 164 165 /* 166 * Save reference to underlying FS 167 */ 168 xmp->nullm_vfs = lowerrootvp->v_mount; 169 170 /* 171 * Save reference. Each mount also holds 172 * a reference on the root vnode. 173 */ 174 error = null_node_create(mp, lowerrootvp, &vp); 175 /* 176 * Unlock the node (either the lower or the alias) 177 */ 178 VOP_UNLOCK(vp, 0, td); 179 /* 180 * Make sure the node alias worked 181 */ 182 if (error) { 183 vrele(lowerrootvp); 184 free(xmp, M_NULLFSMNT); /* XXX */ 185 return (error); 186 } 187 188 /* 189 * Keep a held reference to the root vnode. 190 * It is vrele'd in nullfs_unmount. 191 */ 192 nullm_rootvp = vp; 193 nullm_rootvp->v_flag |= VROOT; 194 xmp->nullm_rootvp = nullm_rootvp; 195 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 196 mp->mnt_flag |= MNT_LOCAL; 197 mp->mnt_data = (qaddr_t) xmp; 198 vfs_getnewfsid(mp); 199 200 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, 201 MNAMELEN - 1, &size); 202 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 203 (void)nullfs_statfs(mp, &mp->mnt_stat, td); 204 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 205 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 206 return (0); 207} 208 209/* 210 * VFS start. Nothing needed here - the start routine 211 * on the underlying filesystem will have been called 212 * when that filesystem was mounted. 213 */ 214static int 215nullfs_start(mp, flags, td) 216 struct mount *mp; 217 int flags; 218 struct thread *td; 219{ 220 return (0); 221 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */ 222} 223 224/* 225 * Free reference to null layer 226 */ 227static int 228nullfs_unmount(mp, mntflags, td) 229 struct mount *mp; 230 int mntflags; 231 struct thread *td; 232{ 233 void *mntdata; 234 int error; 235 int flags = 0; 236 237 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 238 239 if (mntflags & MNT_FORCE) 240 flags |= FORCECLOSE; 241 242 /* There is 1 extra root vnode reference (nullm_rootvp). */ 243 error = vflush(mp, 1, flags); 244 if (error) 245 return (error); 246 247 /* 248 * Finally, throw away the null_mount structure 249 */ 250 mntdata = mp->mnt_data; 251 mp->mnt_data = 0; 252 free(mntdata, M_NULLFSMNT); 253 return 0; 254} 255 256static int 257nullfs_root(mp, vpp) 258 struct mount *mp; 259 struct vnode **vpp; 260{ 261 struct thread *td = curthread; /* XXX */ 262 struct vnode *vp; 263 264 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 265 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 266 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 267 268 /* 269 * Return locked reference to root. 270 */ 271 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 272 VREF(vp); 273 274#ifdef NULLFS_DEBUG 275 if (VOP_ISLOCKED(vp, NULL)) { 276 Debugger("root vnode is locked.\n"); 277 vrele(vp); 278 return (EDEADLK); 279 } 280#endif 281 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 282 *vpp = vp; 283 return 0; 284} 285 286static int 287nullfs_quotactl(mp, cmd, uid, arg, td) 288 struct mount *mp; 289 int cmd; 290 uid_t uid; 291 caddr_t arg; 292 struct thread *td; 293{ 294 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); 295} 296 297static int 298nullfs_statfs(mp, sbp, td) 299 struct mount *mp; 300 struct statfs *sbp; 301 struct thread *td; 302{ 303 int error; 304 struct statfs mstat; 305 306 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 307 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 308 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 309 310 bzero(&mstat, sizeof(mstat)); 311 312 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); 313 if (error) 314 return (error); 315 316 /* now copy across the "interesting" information and fake the rest */ 317 sbp->f_type = mstat.f_type; 318 sbp->f_flags = mstat.f_flags; 319 sbp->f_bsize = mstat.f_bsize; 320 sbp->f_iosize = mstat.f_iosize; 321 sbp->f_blocks = mstat.f_blocks; 322 sbp->f_bfree = mstat.f_bfree; 323 sbp->f_bavail = mstat.f_bavail; 324 sbp->f_files = mstat.f_files; 325 sbp->f_ffree = mstat.f_ffree; 326 if (sbp != &mp->mnt_stat) { 327 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 328 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 329 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 330 } 331 return (0); 332} 333 334static int 335nullfs_sync(mp, waitfor, cred, td) 336 struct mount *mp; 337 int waitfor; 338 struct ucred *cred; 339 struct thread *td; 340{ 341 /* 342 * XXX - Assumes no data cached at null layer. 343 */ 344 return (0); 345} 346 347static int 348nullfs_vget(mp, ino, flags, vpp) 349 struct mount *mp; 350 ino_t ino; 351 int flags; 352 struct vnode **vpp; 353{ 354 int error; 355 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp); 356 if (error) 357 return (error); 358 359 return (null_node_create(mp, *vpp, vpp)); 360} 361 362static int 363nullfs_fhtovp(mp, fidp, vpp) 364 struct mount *mp; 365 struct fid *fidp; 366 struct vnode **vpp; 367{ 368 int error; 369 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 370 if (error) 371 return (error); 372 373 return (null_node_create(mp, *vpp, vpp)); 374} 375 376static int 377nullfs_checkexp(mp, nam, extflagsp, credanonp) 378 struct mount *mp; 379 struct sockaddr *nam; 380 int *extflagsp; 381 struct ucred **credanonp; 382{ 383 384 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 385 extflagsp, credanonp); 386} 387 388static int 389nullfs_vptofh(vp, fhp) 390 struct vnode *vp; 391 struct fid *fhp; 392{ 393 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 394} 395 396static int 397nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname, td) 398 struct mount *mp; 399 int cmd; 400 struct vnode *filename_vp; 401 int namespace; 402 const char *attrname; 403 struct thread *td; 404{ 405 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp, 406 namespace, attrname, td); 407} 408 409 410static struct vfsops null_vfsops = { 411 nullfs_mount, 412 nullfs_start, 413 nullfs_unmount, 414 nullfs_root, 415 nullfs_quotactl, 416 nullfs_statfs, 417 nullfs_sync, 418 nullfs_vget, 419 nullfs_fhtovp, 420 nullfs_checkexp, 421 nullfs_vptofh, 422 nullfs_init, 423 nullfs_uninit, 424 nullfs_extattrctl, 425}; 426 427VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK); 428