null_vfsops.c revision 51138
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 51138 1999-09-11 00:46:08Z 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/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 __P((struct mount *mp, struct fid *fidp, 60 struct vnode **vpp)); 61static int nullfs_checkexp __P((struct mount *mp, struct sockaddr *nam, 62 int *extflagsp, struct ucred **credanonp)); 63static int nullfs_mount __P((struct mount *mp, char *path, caddr_t data, 64 struct nameidata *ndp, struct proc *p)); 65static int nullfs_quotactl __P((struct mount *mp, int cmd, uid_t uid, 66 caddr_t arg, struct proc *p)); 67static int nullfs_root __P((struct mount *mp, struct vnode **vpp)); 68static int nullfs_start __P((struct mount *mp, int flags, struct proc *p)); 69static int nullfs_statfs __P((struct mount *mp, struct statfs *sbp, 70 struct proc *p)); 71static int nullfs_sync __P((struct mount *mp, int waitfor, 72 struct ucred *cred, struct proc *p)); 73static int nullfs_unmount __P((struct mount *mp, int mntflags, 74 struct proc *p)); 75static int nullfs_vget __P((struct mount *mp, ino_t ino, 76 struct vnode **vpp)); 77static int nullfs_vptofh __P((struct vnode *vp, struct fid *fhp)); 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#ifdef DEBUG 99 printf("nullfs_mount(mp = %p)\n", (void *)mp); 100#endif 101 102 /* 103 * Update is a no-op 104 */ 105 if (mp->mnt_flag & MNT_UPDATE) { 106 return (EOPNOTSUPP); 107 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/ 108 } 109 110 /* 111 * Get argument 112 */ 113 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 114 if (error) 115 return (error); 116 117 /* 118 * Unlock lower node to avoid deadlock. 119 * (XXX) VOP_ISLOCKED is needed? 120 */ 121 if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) && 122 VOP_ISLOCKED(mp->mnt_vnodecovered)) { 123 VOP_UNLOCK(mp->mnt_vnodecovered, 0, p); 124 isvnunlocked = 1; 125 } 126 /* 127 * Find lower node 128 */ 129 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 130 UIO_USERSPACE, args.target, p); 131 error = namei(ndp); 132 /* 133 * Re-lock vnode. 134 */ 135 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered)) 136 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, p); 137 138 if (error) 139 return (error); 140 141 /* 142 * Sanity check on lower vnode 143 */ 144 lowerrootvp = ndp->ni_vp; 145 146 vrele(ndp->ni_dvp); 147 ndp->ni_dvp = NULLVP; 148 149 /* 150 * Check multi null mount to avoid `lock against myself' panic. 151 */ 152 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 153#ifdef DEBUG 154 printf("nullfs_mount: multi null mount?\n"); 155#endif 156 return (EDEADLK); 157 } 158 159 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 160 M_NULLFSMNT, M_WAITOK); /* XXX */ 161 162 /* 163 * Save reference to underlying FS 164 */ 165 xmp->nullm_vfs = lowerrootvp->v_mount; 166 167 /* 168 * Save reference. Each mount also holds 169 * a reference on the root vnode. 170 */ 171 error = null_node_create(mp, lowerrootvp, &vp); 172 /* 173 * Unlock the node (either the lower or the alias) 174 */ 175 VOP_UNLOCK(vp, 0, p); 176 /* 177 * Make sure the node alias worked 178 */ 179 if (error) { 180 vrele(lowerrootvp); 181 free(xmp, M_NULLFSMNT); /* XXX */ 182 return (error); 183 } 184 185 /* 186 * Keep a held reference to the root vnode. 187 * It is vrele'd in nullfs_unmount. 188 */ 189 nullm_rootvp = vp; 190 nullm_rootvp->v_flag |= VROOT; 191 xmp->nullm_rootvp = nullm_rootvp; 192 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 193 mp->mnt_flag |= MNT_LOCAL; 194 mp->mnt_data = (qaddr_t) xmp; 195 vfs_getnewfsid(mp); 196 197 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 198 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); 199 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 200 &size); 201 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 202 (void)nullfs_statfs(mp, &mp->mnt_stat, p); 203#ifdef DEBUG 204 printf("nullfs_mount: lower %s, alias at %s\n", 205 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 206#endif 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, p) 217 struct mount *mp; 218 int flags; 219 struct proc *p; 220{ 221 return (0); 222 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */ 223} 224 225/* 226 * Free reference to null layer 227 */ 228static int 229nullfs_unmount(mp, mntflags, p) 230 struct mount *mp; 231 int mntflags; 232 struct proc *p; 233{ 234 struct vnode *nullm_rootvp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 235 int error; 236 int flags = 0; 237 238#ifdef DEBUG 239 printf("nullfs_unmount(mp = %p)\n", (void *)mp); 240#endif 241 242 if (mntflags & MNT_FORCE) 243 flags |= FORCECLOSE; 244 245 /* 246 * Clear out buffer cache. I don't think we 247 * ever get anything cached at this level at the 248 * moment, but who knows... 249 */ 250#if 0 251 mntflushbuf(mp, 0); 252 if (mntinvalbuf(mp, 1)) 253 return (EBUSY); 254#endif 255 if (nullm_rootvp->v_usecount > 1) 256 return (EBUSY); 257 error = vflush(mp, nullm_rootvp, flags); 258 if (error) 259 return (error); 260 261#ifdef DEBUG 262 vprint("alias root of lower", nullm_rootvp); 263#endif 264 /* 265 * Release reference on underlying root vnode 266 */ 267 vrele(nullm_rootvp); 268 /* 269 * And blow it away for future re-use 270 */ 271 vgone(nullm_rootvp); 272 /* 273 * Finally, throw away the null_mount structure 274 */ 275 free(mp->mnt_data, M_NULLFSMNT); /* XXX */ 276 mp->mnt_data = 0; 277 return 0; 278} 279 280static int 281nullfs_root(mp, vpp) 282 struct mount *mp; 283 struct vnode **vpp; 284{ 285 struct proc *p = curproc; /* XXX */ 286 struct vnode *vp; 287 288#ifdef DEBUG 289 printf("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 290 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 291 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 292#endif 293 294 /* 295 * Return locked reference to root. 296 */ 297 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 298 VREF(vp); 299 if (VOP_ISLOCKED(vp)) { 300 /* 301 * XXX 302 * Should we check type of node? 303 */ 304#ifdef DEBUG 305 printf("nullfs_root: multi null mount?\n"); 306#endif 307 vrele(vp); 308 return (EDEADLK); 309 } else 310 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 311 *vpp = vp; 312 return 0; 313} 314 315static int 316nullfs_quotactl(mp, cmd, uid, arg, p) 317 struct mount *mp; 318 int cmd; 319 uid_t uid; 320 caddr_t arg; 321 struct proc *p; 322{ 323 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p); 324} 325 326static int 327nullfs_statfs(mp, sbp, p) 328 struct mount *mp; 329 struct statfs *sbp; 330 struct proc *p; 331{ 332 int error; 333 struct statfs mstat; 334 335#ifdef DEBUG 336 printf("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 337 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 338 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 339#endif 340 341 bzero(&mstat, sizeof(mstat)); 342 343 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p); 344 if (error) 345 return (error); 346 347 /* now copy across the "interesting" information and fake the rest */ 348 sbp->f_type = mstat.f_type; 349 sbp->f_flags = mstat.f_flags; 350 sbp->f_bsize = mstat.f_bsize; 351 sbp->f_iosize = mstat.f_iosize; 352 sbp->f_blocks = mstat.f_blocks; 353 sbp->f_bfree = mstat.f_bfree; 354 sbp->f_bavail = mstat.f_bavail; 355 sbp->f_files = mstat.f_files; 356 sbp->f_ffree = mstat.f_ffree; 357 if (sbp != &mp->mnt_stat) { 358 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 359 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 360 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 361 } 362 return (0); 363} 364 365static int 366nullfs_sync(mp, waitfor, cred, p) 367 struct mount *mp; 368 int waitfor; 369 struct ucred *cred; 370 struct proc *p; 371{ 372 /* 373 * XXX - Assumes no data cached at null layer. 374 */ 375 return (0); 376} 377 378static int 379nullfs_vget(mp, ino, vpp) 380 struct mount *mp; 381 ino_t ino; 382 struct vnode **vpp; 383{ 384 385 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 386} 387 388static int 389nullfs_fhtovp(mp, fidp, vpp) 390 struct mount *mp; 391 struct fid *fidp; 392 struct vnode **vpp; 393{ 394 395 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 396} 397 398static int 399nullfs_checkexp(mp, nam, extflagsp, credanonp) 400 struct mount *mp; 401 struct sockaddr *nam; 402 int *extflagsp; 403 struct ucred **credanonp; 404{ 405 406 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 407 extflagsp, credanonp); 408} 409 410static int 411nullfs_vptofh(vp, fhp) 412 struct vnode *vp; 413 struct fid *fhp; 414{ 415 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 416} 417 418static struct vfsops null_vfsops = { 419 nullfs_mount, 420 nullfs_start, 421 nullfs_unmount, 422 nullfs_root, 423 nullfs_quotactl, 424 nullfs_statfs, 425 nullfs_sync, 426 nullfs_vget, 427 nullfs_fhtovp, 428 nullfs_checkexp, 429 nullfs_vptofh, 430 nullfs_init, 431}; 432 433VFS_SET(null_vfsops, null, VFCF_LOOPBACK); 434