null_vfsops.c revision 67882
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 67882 2000-10-29 13:57:19Z 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/malloc.h> 51#include <sys/vnode.h> 52#include <sys/mount.h> 53#include <sys/namei.h> 54#include <miscfs/nullfs/null.h> 55 56static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure"); 57 58static int nullfs_fhtovp(struct mount *mp, struct fid *fidp, 59 struct vnode **vpp); 60static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam, 61 int *extflagsp, struct ucred **credanonp); 62static int nullfs_mount(struct mount *mp, char *path, caddr_t data, 63 struct nameidata *ndp, struct proc *p); 64static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, 65 caddr_t arg, struct proc *p); 66static int nullfs_root(struct mount *mp, struct vnode **vpp); 67static int nullfs_start(struct mount *mp, int flags, struct proc *p); 68static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 69 struct proc *p); 70static int nullfs_sync(struct mount *mp, int waitfor, 71 struct ucred *cred, struct proc *p); 72static int nullfs_unmount(struct mount *mp, int mntflags, struct proc *p); 73static int nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp); 74static int nullfs_vptofh(struct vnode *vp, struct fid *fhp); 75static int nullfs_extattrctl(struct mount *mp, int cmd, 76 const char *attrname, caddr_t arg, struct proc *p); 77 78/* 79 * Mount null layer 80 */ 81static int 82nullfs_mount(mp, path, data, ndp, p) 83 struct mount *mp; 84 char *path; 85 caddr_t data; 86 struct nameidata *ndp; 87 struct proc *p; 88{ 89 int error = 0; 90 struct null_args args; 91 struct vnode *lowerrootvp, *vp; 92 struct vnode *nullm_rootvp; 93 struct null_mount *xmp; 94 u_int size; 95 int isvnunlocked = 0; 96 97 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 98 99 /* 100 * Update is a no-op 101 */ 102 if (mp->mnt_flag & MNT_UPDATE) { 103 return (EOPNOTSUPP); 104 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/ 105 } 106 107 /* 108 * Get argument 109 */ 110 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 111 if (error) 112 return (error); 113 114 /* 115 * Unlock lower node to avoid deadlock. 116 * (XXX) VOP_ISLOCKED is needed? 117 */ 118 if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) && 119 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 120 VOP_UNLOCK(mp->mnt_vnodecovered, 0, p); 121 isvnunlocked = 1; 122 } 123 /* 124 * Find lower node 125 */ 126 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 127 UIO_USERSPACE, args.target, p); 128 error = namei(ndp); 129 /* 130 * Re-lock vnode. 131 */ 132 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 133 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, p); 134 135 if (error) 136 return (error); 137 NDFREE(ndp, NDF_ONLY_PNBUF); 138 139 /* 140 * Sanity check on lower vnode 141 */ 142 lowerrootvp = ndp->ni_vp; 143 144 vrele(ndp->ni_dvp); 145 ndp->ni_dvp = NULLVP; 146 147 /* 148 * Check multi null mount to avoid `lock against myself' panic. 149 */ 150 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 151 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 152 vput(lowerrootvp); 153 return (EDEADLK); 154 } 155 156 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 157 M_NULLFSMNT, M_WAITOK); /* XXX */ 158 159 /* 160 * Save reference to underlying FS 161 */ 162 xmp->nullm_vfs = lowerrootvp->v_mount; 163 164 /* 165 * Save reference. Each mount also holds 166 * a reference on the root vnode. 167 */ 168 error = null_node_create(mp, lowerrootvp, &vp); 169 /* 170 * Unlock the node (either the lower or the alias) 171 */ 172 VOP_UNLOCK(vp, 0, p); 173 /* 174 * Make sure the node alias worked 175 */ 176 if (error) { 177 vrele(lowerrootvp); 178 free(xmp, M_NULLFSMNT); /* XXX */ 179 return (error); 180 } 181 182 /* 183 * Keep a held reference to the root vnode. 184 * It is vrele'd in nullfs_unmount. 185 */ 186 nullm_rootvp = vp; 187 nullm_rootvp->v_flag |= VROOT; 188 xmp->nullm_rootvp = nullm_rootvp; 189 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 190 mp->mnt_flag |= MNT_LOCAL; 191 mp->mnt_data = (qaddr_t) xmp; 192 vfs_getnewfsid(mp); 193 194 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 195 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); 196 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 197 &size); 198 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 199 (void)nullfs_statfs(mp, &mp->mnt_stat, p); 200 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 201 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 202 return (0); 203} 204 205/* 206 * VFS start. Nothing needed here - the start routine 207 * on the underlying filesystem will have been called 208 * when that filesystem was mounted. 209 */ 210static int 211nullfs_start(mp, flags, p) 212 struct mount *mp; 213 int flags; 214 struct proc *p; 215{ 216 return (0); 217 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */ 218} 219 220/* 221 * Free reference to null layer 222 */ 223static int 224nullfs_unmount(mp, mntflags, p) 225 struct mount *mp; 226 int mntflags; 227 struct proc *p; 228{ 229 struct vnode *vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 230 void *mntdata; 231 int error; 232 int flags = 0; 233 234 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 235 236 if (mntflags & MNT_FORCE) 237 flags |= FORCECLOSE; 238 239 error = VFS_ROOT(mp, &vp); 240 if (error) 241 return (error); 242 if (vp->v_usecount > 2) { 243 NULLFSDEBUG("nullfs_unmount: rootvp is busy(%d)\n", 244 vp->v_usecount); 245 vput(vp); 246 return (EBUSY); 247 } 248 error = vflush(mp, vp, flags); 249 if (error) 250 return (error); 251 252#ifdef NULLFS_DEBUG 253 vprint("alias root of lower", vp); 254#endif 255 vput(vp); 256 /* 257 * Release reference on underlying root vnode 258 */ 259 vrele(vp); 260 /* 261 * And blow it away for future re-use 262 */ 263 vgone(vp); 264 /* 265 * Finally, throw away the null_mount structure 266 */ 267 mntdata = mp->mnt_data; 268 mp->mnt_data = 0; 269 free(mntdata, M_NULLFSMNT); 270 return 0; 271} 272 273static int 274nullfs_root(mp, vpp) 275 struct mount *mp; 276 struct vnode **vpp; 277{ 278 struct proc *p = curproc; /* XXX */ 279 struct vnode *vp; 280 281 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 282 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 283 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 284 285 /* 286 * Return locked reference to root. 287 */ 288 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 289 VREF(vp); 290 291#ifdef NULLFS_DEBUG 292 if (VOP_ISLOCKED(vp, NULL)) { 293 Debugger("root vnode is locked.\n"); 294 vrele(vp); 295 return (EDEADLK); 296 } 297#endif 298 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 299 *vpp = vp; 300 return 0; 301} 302 303static int 304nullfs_quotactl(mp, cmd, uid, arg, p) 305 struct mount *mp; 306 int cmd; 307 uid_t uid; 308 caddr_t arg; 309 struct proc *p; 310{ 311 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p); 312} 313 314static int 315nullfs_statfs(mp, sbp, p) 316 struct mount *mp; 317 struct statfs *sbp; 318 struct proc *p; 319{ 320 int error; 321 struct statfs mstat; 322 323 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 324 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 325 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 326 327 bzero(&mstat, sizeof(mstat)); 328 329 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p); 330 if (error) 331 return (error); 332 333 /* now copy across the "interesting" information and fake the rest */ 334 sbp->f_type = mstat.f_type; 335 sbp->f_flags = mstat.f_flags; 336 sbp->f_bsize = mstat.f_bsize; 337 sbp->f_iosize = mstat.f_iosize; 338 sbp->f_blocks = mstat.f_blocks; 339 sbp->f_bfree = mstat.f_bfree; 340 sbp->f_bavail = mstat.f_bavail; 341 sbp->f_files = mstat.f_files; 342 sbp->f_ffree = mstat.f_ffree; 343 if (sbp != &mp->mnt_stat) { 344 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 345 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 346 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 347 } 348 return (0); 349} 350 351static int 352nullfs_sync(mp, waitfor, cred, p) 353 struct mount *mp; 354 int waitfor; 355 struct ucred *cred; 356 struct proc *p; 357{ 358 /* 359 * XXX - Assumes no data cached at null layer. 360 */ 361 return (0); 362} 363 364static int 365nullfs_vget(mp, ino, vpp) 366 struct mount *mp; 367 ino_t ino; 368 struct vnode **vpp; 369{ 370 int error; 371 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 372 if (error) 373 return (error); 374 375 return (null_node_create(mp, *vpp, vpp)); 376} 377 378static int 379nullfs_fhtovp(mp, fidp, vpp) 380 struct mount *mp; 381 struct fid *fidp; 382 struct vnode **vpp; 383{ 384 int error; 385 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 386 if (error) 387 return (error); 388 389 return (null_node_create(mp, *vpp, vpp)); 390} 391 392static int 393nullfs_checkexp(mp, nam, extflagsp, credanonp) 394 struct mount *mp; 395 struct sockaddr *nam; 396 int *extflagsp; 397 struct ucred **credanonp; 398{ 399 400 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 401 extflagsp, credanonp); 402} 403 404static int 405nullfs_vptofh(vp, fhp) 406 struct vnode *vp; 407 struct fid *fhp; 408{ 409 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 410} 411 412static int 413nullfs_extattrctl(mp, cmd, attrname, arg, p) 414 struct mount *mp; 415 int cmd; 416 const char *attrname; 417 caddr_t arg; 418 struct proc *p; 419{ 420 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, 421 arg, p); 422} 423 424 425static struct vfsops null_vfsops = { 426 nullfs_mount, 427 nullfs_start, 428 nullfs_unmount, 429 nullfs_root, 430 nullfs_quotactl, 431 nullfs_statfs, 432 nullfs_sync, 433 nullfs_vget, 434 nullfs_fhtovp, 435 nullfs_checkexp, 436 nullfs_vptofh, 437 nullfs_init, 438 nullfs_uninit, 439 nullfs_extattrctl, 440}; 441 442VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK); 443