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 35 * $FreeBSD$ 36 */ 37 38 /* 39 * Null Layer 40 * (See null_vnops.c for a description of what this does.) 41 */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/kdb.h> 46 #include <sys/kernel.h> 47 #include <sys/lock.h> 48 #include <sys/malloc.h> 49 #include <sys/mount.h> 50 #include <sys/namei.h> 51 #include <sys/proc.h> 52 #include <sys/vnode.h> 53 54 #include <fs/nullfs/null.h> 55 56 static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure"); 57 58 static vfs_fhtovp_t nullfs_fhtovp; 59 static vfs_checkexp_t nullfs_checkexp; 60 static vfs_mount_t nullfs_mount; 61 static vfs_quotactl_t nullfs_quotactl; 62 static vfs_root_t nullfs_root; 63 static vfs_sync_t nullfs_sync; 64 static vfs_statfs_t nullfs_statfs; 65 static vfs_unmount_t nullfs_unmount; 66 static vfs_vget_t nullfs_vget; 67 static vfs_vptofh_t nullfs_vptofh; 68 static vfs_extattrctl_t nullfs_extattrctl; 69 70 /* 71 * Mount null layer 72 */ 73 static int 74 nullfs_mount(struct mount *mp, struct thread *td) 75 { 76 int error = 0; 77 struct vnode *lowerrootvp, *vp; 78 struct vnode *nullm_rootvp; 79 struct null_mount *xmp; 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 (mp->mnt_flag & MNT_ROOTFS) 87 return (EOPNOTSUPP); 88 /* 89 * Update is a no-op 90 */ 91 if (mp->mnt_flag & MNT_UPDATE) { 92 return (EOPNOTSUPP); 93 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, td);*/ 94 } 95 96 /* 97 * Get argument 98 */ 99 error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len); 100 if (error || target[len - 1] != '\0') 101 return (EINVAL); 102 103 /* 104 * Unlock lower node to avoid deadlock. 105 * (XXX) VOP_ISLOCKED is needed? 106 */ 107 if ((mp->mnt_vnodecovered->v_op == &null_vnodeops) && 108 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 109 VOP_UNLOCK(mp->mnt_vnodecovered, 0, td); 110 isvnunlocked = 1; 111 } 112 /* 113 * Find lower node 114 */ 115 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF, 116 UIO_SYSSPACE, target, td); 117 error = namei(ndp); 118 /* 119 * Re-lock vnode. 120 */ 121 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 122 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td); 123 124 if (error) 125 return (error); 126 NDFREE(ndp, NDF_ONLY_PNBUF); 127 128 /* 129 * Sanity check on lower vnode 130 */ 131 lowerrootvp = ndp->ni_vp; 132 133 vrele(ndp->ni_dvp); 134 ndp->ni_dvp = NULLVP; 135 136 /* 137 * Check multi null mount to avoid `lock against myself' panic. 138 */ 139 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 140 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 141 vput(lowerrootvp); 142 return (EDEADLK); 143 } 144 145 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 146 M_NULLFSMNT, M_WAITOK); /* XXX */ 147 148 /* 149 * Save reference to underlying FS 150 */ 151 xmp->nullm_vfs = lowerrootvp->v_mount; 152 153 /* 154 * Save reference. Each mount also holds 155 * a reference on the root vnode. 156 */ 157 error = null_nodeget(mp, lowerrootvp, &vp); 158 /* 159 * Make sure the node alias worked 160 */ 161 if (error) { 162 VOP_UNLOCK(vp, 0, td); 163 vrele(lowerrootvp); 164 free(xmp, M_NULLFSMNT); /* XXX */ 165 return (error); 166 } 167 168 /* 169 * Keep a held reference to the root vnode. 170 * It is vrele'd in nullfs_unmount. 171 */ 172 nullm_rootvp = vp; 173 nullm_rootvp->v_vflag |= VV_ROOT; 174 xmp->nullm_rootvp = nullm_rootvp; 175 176 /* 177 * Unlock the node (either the lower or the alias) 178 */ 179 VOP_UNLOCK(vp, 0, td); 180 181 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 182 mp->mnt_flag |= MNT_LOCAL; 183 mp->mnt_data = (qaddr_t) xmp; 184 vfs_getnewfsid(mp); 185 186 vfs_mountedfrom(mp, target); 187 188 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 189 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 190 return (0); 191 } 192 193 /* 194 * Free reference to null layer 195 */ 196 static int 197 nullfs_unmount(mp, mntflags, td) 198 struct mount *mp; 199 int mntflags; 200 struct thread *td; 201 { 202 void *mntdata; 203 int error; 204 int flags = 0; 205 206 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 207 208 if (mntflags & MNT_FORCE) 209 flags |= FORCECLOSE; 210 211 /* There is 1 extra root vnode reference (nullm_rootvp). */ 212 error = vflush(mp, 1, flags, td); 213 if (error) 214 return (error); 215 216 /* 217 * Finally, throw away the null_mount structure 218 */ 219 mntdata = mp->mnt_data; 220 mp->mnt_data = 0; 221 free(mntdata, M_NULLFSMNT); 222 return 0; 223 } 224 225 static int 226 nullfs_root(mp, flags, vpp, td) 227 struct mount *mp; 228 int flags; 229 struct vnode **vpp; 230 struct thread *td; 231 { 232 struct vnode *vp; 233 234 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 235 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 236 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 237 238 /* 239 * Return locked reference to root. 240 */ 241 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 242 VREF(vp); 243 244 #ifdef NULLFS_DEBUG 245 if (VOP_ISLOCKED(vp, NULL)) { 246 kdb_enter("root vnode is locked.\n"); 247 vrele(vp); 248 return (EDEADLK); 249 } 250 #endif 251 vn_lock(vp, flags | LK_RETRY, td); 252 *vpp = vp; 253 return 0; 254 } 255 256 static int 257 nullfs_quotactl(mp, cmd, uid, arg, td) 258 struct mount *mp; 259 int cmd; 260 uid_t uid; 261 caddr_t arg; 262 struct thread *td; 263 { 264 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); 265 } 266 267 static int 268 nullfs_statfs(mp, sbp, td) 269 struct mount *mp; 270 struct statfs *sbp; 271 struct thread *td; 272 { 273 int error; 274 struct statfs mstat; 275 276 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 277 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 278 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 279 280 bzero(&mstat, sizeof(mstat)); 281 282 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); 283 if (error) 284 return (error); 285 286 /* now copy across the "interesting" information and fake the rest */ 287 sbp->f_type = mstat.f_type; 288 sbp->f_flags = mstat.f_flags; 289 sbp->f_bsize = mstat.f_bsize; 290 sbp->f_iosize = mstat.f_iosize; 291 sbp->f_blocks = mstat.f_blocks; 292 sbp->f_bfree = mstat.f_bfree; 293 sbp->f_bavail = mstat.f_bavail; 294 sbp->f_files = mstat.f_files; 295 sbp->f_ffree = mstat.f_ffree; 296 return (0); 297 } 298 299 static int 300 nullfs_sync(mp, waitfor, td) 301 struct mount *mp; 302 int waitfor; 303 struct thread *td; 304 { 305 /* 306 * XXX - Assumes no data cached at null layer. 307 */ 308 return (0); 309 } 310 311 static int 312 nullfs_vget(mp, ino, flags, vpp) 313 struct mount *mp; 314 ino_t ino; 315 int flags; 316 struct vnode **vpp; 317 { 318 int error; 319 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp); 320 if (error) 321 return (error); 322 323 return (null_nodeget(mp, *vpp, vpp)); 324 } 325 326 static int 327 nullfs_fhtovp(mp, fidp, vpp) 328 struct mount *mp; 329 struct fid *fidp; 330 struct vnode **vpp; 331 { 332 int error; 333 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 334 if (error) 335 return (error); 336 337 return (null_nodeget(mp, *vpp, vpp)); 338 } 339 340 static int 341 nullfs_checkexp(mp, nam, extflagsp, credanonp) 342 struct mount *mp; 343 struct sockaddr *nam; 344 int *extflagsp; 345 struct ucred **credanonp; 346 { 347 348 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 349 extflagsp, credanonp); 350 } 351 352 static int 353 nullfs_vptofh(vp, fhp) 354 struct vnode *vp; 355 struct fid *fhp; 356 { 357 struct vnode *lvp; 358 359 lvp = NULLVPTOLOWERVP(vp); 360 return VFS_VPTOFH(lvp, fhp); 361 } 362 363 static int 364 nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname, td) 365 struct mount *mp; 366 int cmd; 367 struct vnode *filename_vp; 368 int namespace; 369 const char *attrname; 370 struct thread *td; 371 { 372 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp, 373 namespace, attrname, td); 374 } 375 376 377 static struct vfsops null_vfsops = { 378 .vfs_checkexp = nullfs_checkexp, 379 .vfs_extattrctl = nullfs_extattrctl, 380 .vfs_fhtovp = nullfs_fhtovp, 381 .vfs_init = nullfs_init, 382 .vfs_mount = nullfs_mount, 383 .vfs_quotactl = nullfs_quotactl, 384 .vfs_root = nullfs_root, 385 .vfs_statfs = nullfs_statfs, 386 .vfs_sync = nullfs_sync, 387 .vfs_uninit = nullfs_uninit, 388 .vfs_unmount = nullfs_unmount, 389 .vfs_vget = nullfs_vget, 390 .vfs_vptofh = nullfs_vptofh, 391 }; 392 393 VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK); 394