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: src/sys/miscfs/nullfs/null_vfsops.c,v 1.35.2.3 2001/07/26 20:37:11 iedowse Exp $ 40 * $DragonFly: src/sys/vfs/nullfs/null_vfsops.c,v 1.9 2004/04/24 04:32:04 drhodus Exp $ 41 */ 42 43 /* 44 * Null Layer 45 * (See null_vnops.c for a description of what this does.) 46 */ 47 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/kernel.h> 51 #include <sys/proc.h> 52 #include <sys/malloc.h> 53 #include <sys/vnode.h> 54 #include <sys/mount.h> 55 #include <sys/namei.h> 56 #include "null.h" 57 58 static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure"); 59 60 static int nullfs_fhtovp(struct mount *mp, struct fid *fidp, 61 struct vnode **vpp); 62 static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam, 63 int *extflagsp, struct ucred **credanonp); 64 static int nullfs_mount(struct mount *mp, char *path, caddr_t data, 65 struct nameidata *ndp, struct thread *td); 66 static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, 67 caddr_t arg, struct thread *td); 68 static int nullfs_root(struct mount *mp, struct vnode **vpp); 69 static int nullfs_start(struct mount *mp, int flags, struct thread *td); 70 static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 71 struct thread *td); 72 static int nullfs_sync(struct mount *mp, int waitfor, struct thread *td); 73 static int nullfs_unmount(struct mount *mp, int mntflags, struct thread *td); 74 static int nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp); 75 static int nullfs_vptofh(struct vnode *vp, struct fid *fhp); 76 static int nullfs_extattrctl(struct mount *mp, int cmd, 77 const char *attrname, caddr_t arg, struct thread *td); 78 79 /* 80 * Mount null layer 81 */ 82 static int 83 nullfs_mount(struct mount *mp, char *path, caddr_t data, struct nameidata *ndp, 84 struct thread *td) 85 { 86 int error = 0; 87 struct null_args args; 88 struct vnode *lowerrootvp, *vp; 89 struct vnode *nullm_rootvp; 90 struct null_mount *xmp; 91 u_int size; 92 int isvnunlocked = 0; 93 94 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 95 96 /* 97 * Update is a no-op 98 */ 99 if (mp->mnt_flag & MNT_UPDATE) { 100 return (EOPNOTSUPP); 101 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/ 102 } 103 104 /* 105 * Get argument 106 */ 107 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 108 if (error) 109 return (error); 110 111 /* 112 * Unlock lower node to avoid deadlock. 113 * (XXX) VOP_ISLOCKED is needed? 114 */ 115 if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) && 116 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 117 VOP_UNLOCK(mp->mnt_vnodecovered, NULL, 0, td); 118 isvnunlocked = 1; 119 } 120 /* 121 * Find lower node 122 */ 123 NDINIT(ndp, NAMEI_LOOKUP, CNP_FOLLOW | CNP_WANTPARENT | CNP_LOCKLEAF, 124 UIO_USERSPACE, args.target, td); 125 error = namei(ndp); 126 /* 127 * Re-lock vnode. 128 */ 129 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 130 vn_lock(mp->mnt_vnodecovered, NULL, LK_EXCLUSIVE | LK_RETRY, td); 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 vrele(ndp->ni_dvp); 142 ndp->ni_dvp = NULLVP; 143 144 /* 145 * Check multi null mount to avoid `lock against myself' panic. 146 */ 147 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 148 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 149 vput(lowerrootvp); 150 return (EDEADLK); 151 } 152 153 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 154 M_NULLFSMNT, M_WAITOK); /* XXX */ 155 156 /* 157 * Save reference to underlying FS 158 */ 159 xmp->nullm_vfs = lowerrootvp->v_mount; 160 161 /* 162 * Save reference. Each mount also holds 163 * a reference on the root vnode. 164 */ 165 error = null_node_create(mp, lowerrootvp, &vp); 166 /* 167 * Unlock the node (either the lower or the alias) 168 */ 169 VOP_UNLOCK(vp, NULL, 0, td); 170 /* 171 * Make sure the node alias worked 172 */ 173 if (error) { 174 vrele(lowerrootvp); 175 free(xmp, M_NULLFSMNT); /* XXX */ 176 return (error); 177 } 178 179 /* 180 * Keep a held reference to the root vnode. 181 * It is vrele'd in nullfs_unmount. 182 */ 183 nullm_rootvp = vp; 184 nullm_rootvp->v_flag |= VROOT; 185 xmp->nullm_rootvp = nullm_rootvp; 186 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 187 mp->mnt_flag |= MNT_LOCAL; 188 mp->mnt_data = (qaddr_t) xmp; 189 vfs_getnewfsid(mp); 190 191 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 192 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); 193 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 194 &size); 195 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 196 (void)nullfs_statfs(mp, &mp->mnt_stat, td); 197 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 198 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 199 return (0); 200 } 201 202 /* 203 * VFS start. Nothing needed here - the start routine 204 * on the underlying filesystem will have been called 205 * when that filesystem was mounted. 206 */ 207 static int 208 nullfs_start(struct mount *mp, int flags, struct thread *td) 209 { 210 return (0); 211 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */ 212 } 213 214 /* 215 * Free reference to null layer 216 */ 217 static int 218 nullfs_unmount(struct mount *mp, int mntflags, struct thread *td) 219 { 220 void *mntdata; 221 int error; 222 int flags = 0; 223 224 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 225 226 if (mntflags & MNT_FORCE) 227 flags |= FORCECLOSE; 228 229 /* There is 1 extra root vnode reference (nullm_rootvp). */ 230 error = vflush(mp, 1, flags); 231 if (error) 232 return (error); 233 234 /* 235 * Finally, throw away the null_mount structure 236 */ 237 mntdata = mp->mnt_data; 238 mp->mnt_data = 0; 239 free(mntdata, M_NULLFSMNT); 240 return 0; 241 } 242 243 static int 244 nullfs_root(struct mount *mp, struct vnode **vpp) 245 { 246 struct thread *td = curthread; /* XXX */ 247 struct vnode *vp; 248 249 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 250 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 251 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 252 253 /* 254 * Return locked reference to root. 255 */ 256 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 257 vref(vp); 258 259 #ifdef NULLFS_DEBUG 260 if (VOP_ISLOCKED(vp, NULL)) { 261 Debugger("root vnode is locked.\n"); 262 vrele(vp); 263 return (EDEADLK); 264 } 265 #endif 266 vn_lock(vp, NULL, LK_EXCLUSIVE | LK_RETRY, td); 267 *vpp = vp; 268 return 0; 269 } 270 271 static int 272 nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg, 273 struct thread *td) 274 { 275 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); 276 } 277 278 static int 279 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td) 280 { 281 int error; 282 struct statfs mstat; 283 284 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 285 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 286 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 287 288 bzero(&mstat, sizeof(mstat)); 289 290 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); 291 if (error) 292 return (error); 293 294 /* now copy across the "interesting" information and fake the rest */ 295 sbp->f_type = mstat.f_type; 296 sbp->f_flags = mstat.f_flags; 297 sbp->f_bsize = mstat.f_bsize; 298 sbp->f_iosize = mstat.f_iosize; 299 sbp->f_blocks = mstat.f_blocks; 300 sbp->f_bfree = mstat.f_bfree; 301 sbp->f_bavail = mstat.f_bavail; 302 sbp->f_files = mstat.f_files; 303 sbp->f_ffree = mstat.f_ffree; 304 if (sbp != &mp->mnt_stat) { 305 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 306 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 307 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 308 } 309 return (0); 310 } 311 312 static int 313 nullfs_sync(struct mount *mp, int waitfor, struct thread *td) 314 { 315 /* 316 * XXX - Assumes no data cached at null layer. 317 */ 318 return (0); 319 } 320 321 static int 322 nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp) 323 { 324 325 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 326 } 327 328 static int 329 nullfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp) 330 { 331 332 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 333 } 334 335 static int 336 nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp, 337 struct ucred **credanonp) 338 { 339 340 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 341 extflagsp, credanonp); 342 } 343 344 static int 345 nullfs_vptofh(struct vnode *vp, struct fid *fhp) 346 { 347 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 348 } 349 350 static int 351 nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg, 352 struct thread *td) 353 { 354 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, 355 arg, td); 356 } 357 358 359 static struct vfsops null_vfsops = { 360 nullfs_mount, 361 nullfs_start, 362 nullfs_unmount, 363 nullfs_root, 364 nullfs_quotactl, 365 nullfs_statfs, 366 nullfs_sync, 367 nullfs_vget, 368 nullfs_fhtovp, 369 nullfs_checkexp, 370 nullfs_vptofh, 371 nullfs_init, 372 nullfs_uninit, 373 nullfs_extattrctl, 374 }; 375 376 VFS_SET(null_vfsops, null, VFCF_LOOPBACK); 377