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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94 33 * 34 * @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
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68 69/* 70 * Mount null layer 71 */ 72static int 73nullfs_mount(struct mount *mp) 74{ 75 int error = 0; 76 struct vnode *lowerrootvp, *vp; 77 struct vnode *nullm_rootvp; 78 struct null_mount *xmp; 79 struct thread *td = curthread; 80 char *target; 81 int isvnunlocked = 0, len; 82 struct nameidata nd, *ndp = &nd; 83 84 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 85 86 if (!prison_allow(td->td_ucred, PR_ALLOW_MOUNT_NULLFS)) 87 return (EPERM); 88 if (mp->mnt_flag & MNT_ROOTFS) 89 return (EOPNOTSUPP); 90 91 /* 92 * Update is a no-op 93 */ 94 if (mp->mnt_flag & MNT_UPDATE) { 95 /* 96 * Only support update mounts for NFS export. 97 */ 98 if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0)) 99 return (0); 100 else 101 return (EOPNOTSUPP); 102 } 103 104 /* 105 * Get argument 106 */ 107 error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len); 108 if (error || target[len - 1] != '\0') 109 return (EINVAL); 110 111 /* 112 * Unlock lower node to avoid possible deadlock. 113 */ 114 if ((mp->mnt_vnodecovered->v_op == &null_vnodeops) && 115 VOP_ISLOCKED(mp->mnt_vnodecovered) == LK_EXCLUSIVE) { 116 VOP_UNLOCK(mp->mnt_vnodecovered, 0); 117 isvnunlocked = 1; 118 } 119 /* 120 * Find lower node 121 */ 122 NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, UIO_SYSSPACE, target, curthread); 123 error = namei(ndp); 124 125 /* 126 * Re-lock vnode. 127 * XXXKIB This is deadlock-prone as well. 128 */ 129 if (isvnunlocked) 130 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY); 131 132 if (error) 133 return (error); 134 NDFREE(ndp, NDF_ONLY_PNBUF); 135 136 /* 137 * Sanity check on lower vnode 138 */ 139 lowerrootvp = ndp->ni_vp; 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 | M_ZERO); 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 free(xmp, M_NULLFSMNT); 168 return (error); 169 } 170 171 /* 172 * Keep a held reference to the root vnode. 173 * It is vrele'd in nullfs_unmount. 174 */ 175 nullm_rootvp = vp; 176 nullm_rootvp->v_vflag |= VV_ROOT; 177 xmp->nullm_rootvp = nullm_rootvp; 178 179 /* 180 * Unlock the node (either the lower or the alias) 181 */ 182 VOP_UNLOCK(vp, 0); 183 184 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) { 185 MNT_ILOCK(mp); 186 mp->mnt_flag |= MNT_LOCAL; 187 MNT_IUNLOCK(mp); 188 } 189 190 xmp->nullm_flags |= NULLM_CACHE; 191 if (vfs_getopt(mp->mnt_optnew, "nocache", NULL, NULL) == 0) 192 xmp->nullm_flags &= ~NULLM_CACHE; 193 194 MNT_ILOCK(mp); 195 if ((xmp->nullm_flags & NULLM_CACHE) != 0) { 196 mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag & 197 (MNTK_MPSAFE | MNTK_SHARED_WRITES | MNTK_LOOKUP_SHARED | 198 MNTK_EXTENDED_SHARED); 199 } 200 mp->mnt_kern_flag |= MNTK_LOOKUP_EXCL_DOTDOT; 201 MNT_IUNLOCK(mp); 202 mp->mnt_data = xmp; 203 vfs_getnewfsid(mp); 204 if ((xmp->nullm_flags & NULLM_CACHE) != 0) { 205 MNT_ILOCK(xmp->nullm_vfs); 206 TAILQ_INSERT_TAIL(&xmp->nullm_vfs->mnt_uppers, mp, 207 mnt_upper_link); 208 MNT_IUNLOCK(xmp->nullm_vfs); 209 } 210 211 vfs_mountedfrom(mp, target); 212 213 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 214 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 215 return (0); 216} 217 218/* 219 * Free reference to null layer 220 */ 221static int 222nullfs_unmount(mp, mntflags) 223 struct mount *mp; 224 int mntflags; 225{ 226 struct null_mount *mntdata; 227 struct mount *ump; 228 int error, flags; 229 230 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 231 232 if (mntflags & MNT_FORCE) 233 flags = FORCECLOSE; 234 else 235 flags = 0; 236 237 /* There is 1 extra root vnode reference (nullm_rootvp). */ 238 error = vflush(mp, 1, flags, curthread); 239 if (error) 240 return (error); 241 242 /* 243 * Finally, throw away the null_mount structure 244 */ 245 mntdata = mp->mnt_data; 246 ump = mntdata->nullm_vfs; 247 if ((mntdata->nullm_flags & NULLM_CACHE) != 0) { 248 MNT_ILOCK(ump); 249 while ((ump->mnt_kern_flag & MNTK_VGONE_UPPER) != 0) { 250 ump->mnt_kern_flag |= MNTK_VGONE_WAITER; 251 msleep(&ump->mnt_uppers, &ump->mnt_mtx, 0, "vgnupw", 0); 252 } 253 TAILQ_REMOVE(&ump->mnt_uppers, mp, mnt_upper_link); 254 MNT_IUNLOCK(ump); 255 } 256 mp->mnt_data = NULL; 257 free(mntdata, M_NULLFSMNT); 258 return (0); 259} 260 261static int 262nullfs_root(mp, flags, vpp) 263 struct mount *mp; 264 int flags; 265 struct vnode **vpp; 266{ 267 struct vnode *vp; 268 269 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 270 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 271 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 272 273 /* 274 * Return locked reference to root. 275 */ 276 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 277 VREF(vp); 278 279 ASSERT_VOP_UNLOCKED(vp, "root vnode is locked"); 280 vn_lock(vp, flags | LK_RETRY); 281 *vpp = vp; 282 return 0; 283} 284 285static int 286nullfs_quotactl(mp, cmd, uid, arg) 287 struct mount *mp; 288 int cmd; 289 uid_t uid; 290 void *arg; 291{ 292 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg); 293} 294 295static int 296nullfs_statfs(mp, sbp) 297 struct mount *mp; 298 struct statfs *sbp; 299{ 300 int error; 301 struct statfs mstat; 302 303 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 304 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 305 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 306 307 bzero(&mstat, sizeof(mstat)); 308 309 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat); 310 if (error) 311 return (error); 312 313 /* now copy across the "interesting" information and fake the rest */ 314 sbp->f_type = mstat.f_type; 315 sbp->f_flags = mstat.f_flags; 316 sbp->f_bsize = mstat.f_bsize; 317 sbp->f_iosize = mstat.f_iosize; 318 sbp->f_blocks = mstat.f_blocks; 319 sbp->f_bfree = mstat.f_bfree; 320 sbp->f_bavail = mstat.f_bavail; 321 sbp->f_files = mstat.f_files; 322 sbp->f_ffree = mstat.f_ffree; 323 return (0); 324} 325 326static int 327nullfs_sync(mp, waitfor) 328 struct mount *mp; 329 int waitfor; 330{ 331 /* 332 * XXX - Assumes no data cached at null layer. 333 */ 334 return (0); 335} 336 337static int 338nullfs_vget(mp, ino, flags, vpp) 339 struct mount *mp; 340 ino_t ino; 341 int flags; 342 struct vnode **vpp; 343{ 344 int error; 345 346 KASSERT((flags & LK_TYPE_MASK) != 0, 347 ("nullfs_vget: no lock requested")); 348 349 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp); 350 if (error != 0) 351 return (error); 352 return (null_nodeget(mp, *vpp, vpp)); 353} 354 355static int 356nullfs_fhtovp(mp, fidp, flags, vpp) 357 struct mount *mp; 358 struct fid *fidp; 359 int flags; 360 struct vnode **vpp; 361{ 362 int error; 363 364 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, flags, 365 vpp); 366 if (error != 0) 367 return (error); 368 return (null_nodeget(mp, *vpp, vpp)); 369} 370 371static int 372nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname) 373 struct mount *mp; 374 int cmd; 375 struct vnode *filename_vp; 376 int namespace; 377 const char *attrname; 378{ 379 380 return (VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, 381 filename_vp, namespace, attrname)); 382} 383 384static void 385nullfs_reclaim_lowervp(struct mount *mp, struct vnode *lowervp) 386{ 387 struct vnode *vp; 388 389 vp = null_hashget(mp, lowervp); 390 if (vp == NULL) 391 return;
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