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 1.11 2004/08/17 18:57:34 dillon 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 extern struct vnodeopv_entry_desc null_vnodeop_entries[]; 59 60 static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure"); 61 62 static int nullfs_fhtovp(struct mount *mp, struct fid *fidp, 63 struct vnode **vpp); 64 static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam, 65 int *extflagsp, struct ucred **credanonp); 66 static int nullfs_mount(struct mount *mp, char *path, caddr_t data, 67 struct nameidata *ndp, struct thread *td); 68 static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, 69 caddr_t arg, struct thread *td); 70 static int nullfs_root(struct mount *mp, struct vnode **vpp); 71 static int nullfs_start(struct mount *mp, int flags, struct thread *td); 72 static int nullfs_statfs(struct mount *mp, struct statfs *sbp, 73 struct thread *td); 74 static int nullfs_sync(struct mount *mp, int waitfor, struct thread *td); 75 static int nullfs_unmount(struct mount *mp, int mntflags, struct thread *td); 76 static int nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp); 77 static int nullfs_vptofh(struct vnode *vp, struct fid *fhp); 78 static int nullfs_extattrctl(struct mount *mp, int cmd, 79 const char *attrname, caddr_t arg, struct thread *td); 80 81 /* 82 * Mount null layer 83 */ 84 static int 85 nullfs_mount(struct mount *mp, char *path, caddr_t data, struct nameidata *ndp, 86 struct thread *td) 87 { 88 int error = 0; 89 struct null_args args; 90 struct vnode *lowerrootvp, *vp; 91 struct vnode *nullm_rootvp; 92 struct null_mount *xmp; 93 u_int size; 94 int isvnunlocked = 0; 95 96 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); 97 98 /* 99 * Update is a no-op 100 */ 101 if (mp->mnt_flag & MNT_UPDATE) { 102 return (EOPNOTSUPP); 103 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/ 104 } 105 106 /* 107 * Get argument 108 */ 109 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 110 if (error) 111 return (error); 112 113 /* 114 * Unlock lower node to avoid deadlock. 115 * (XXX) VOP_ISLOCKED is needed? 116 */ 117 if ((mp->mnt_vnodecovered->v_tag == VT_NULL) && 118 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 119 VOP_UNLOCK(mp->mnt_vnodecovered, NULL, 0, td); 120 isvnunlocked = 1; 121 } 122 /* 123 * Find lower node 124 */ 125 NDINIT(ndp, NAMEI_LOOKUP, CNP_FOLLOW | CNP_WANTPARENT | CNP_LOCKLEAF, 126 UIO_USERSPACE, args.target, td); 127 error = namei(ndp); 128 /* 129 * Re-lock vnode. 130 */ 131 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 132 vn_lock(mp->mnt_vnodecovered, NULL, LK_EXCLUSIVE | LK_RETRY, td); 133 134 if (error) 135 return (error); 136 NDFREE(ndp, NDF_ONLY_PNBUF); 137 138 /* 139 * Sanity check on lower vnode 140 */ 141 lowerrootvp = ndp->ni_vp; 142 143 vrele(ndp->ni_dvp); 144 ndp->ni_dvp = NULLVP; 145 146 /* 147 * Check multi null mount to avoid `lock against myself' panic. 148 */ 149 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 150 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 151 vput(lowerrootvp); 152 return (EDEADLK); 153 } 154 155 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 156 M_NULLFSMNT, M_WAITOK); /* XXX */ 157 158 /* 159 * Save reference to underlying FS 160 */ 161 xmp->nullm_vfs = lowerrootvp->v_mount; 162 163 vfs_add_vnodeops(&mp->mnt_vn_ops, null_vnodeop_entries); 164 165 /* 166 * Save reference. Each mount also holds 167 * a reference on the root vnode. 168 */ 169 error = null_node_create(mp, lowerrootvp, &vp); 170 /* 171 * Unlock the node (either the lower or the alias) 172 */ 173 VOP_UNLOCK(vp, NULL, 0, td); 174 /* 175 * Make sure the node alias worked 176 */ 177 if (error) { 178 vrele(lowerrootvp); 179 free(xmp, M_NULLFSMNT); /* XXX */ 180 return (error); 181 } 182 183 /* 184 * Keep a held reference to the root vnode. 185 * It is vrele'd in nullfs_unmount. 186 */ 187 nullm_rootvp = vp; 188 nullm_rootvp->v_flag |= VROOT; 189 xmp->nullm_rootvp = nullm_rootvp; 190 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 191 mp->mnt_flag |= MNT_LOCAL; 192 mp->mnt_data = (qaddr_t) xmp; 193 vfs_getnewfsid(mp); 194 195 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 196 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); 197 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 198 &size); 199 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 200 (void)nullfs_statfs(mp, &mp->mnt_stat, td); 201 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 202 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 203 return (0); 204 } 205 206 /* 207 * VFS start. Nothing needed here - the start routine 208 * on the underlying filesystem will have been called 209 * when that filesystem was mounted. 210 */ 211 static int 212 nullfs_start(struct mount *mp, int flags, struct thread *td) 213 { 214 return (0); 215 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */ 216 } 217 218 /* 219 * Free reference to null layer 220 */ 221 static int 222 nullfs_unmount(struct mount *mp, int mntflags, struct thread *td) 223 { 224 void *mntdata; 225 int error; 226 int flags = 0; 227 228 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 229 230 if (mntflags & MNT_FORCE) 231 flags |= FORCECLOSE; 232 233 /* There is 1 extra root vnode reference (nullm_rootvp). */ 234 error = vflush(mp, 1, flags); 235 if (error) 236 return (error); 237 238 /* 239 * Finally, throw away the null_mount structure 240 */ 241 mntdata = mp->mnt_data; 242 mp->mnt_data = 0; 243 free(mntdata, M_NULLFSMNT); 244 return 0; 245 } 246 247 static int 248 nullfs_root(struct mount *mp, struct vnode **vpp) 249 { 250 struct thread *td = curthread; /* XXX */ 251 struct vnode *vp; 252 253 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 254 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 255 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 256 257 /* 258 * Return locked reference to root. 259 */ 260 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 261 vref(vp); 262 263 #ifdef NULLFS_DEBUG 264 if (VOP_ISLOCKED(vp, NULL)) { 265 Debugger("root vnode is locked.\n"); 266 vrele(vp); 267 return (EDEADLK); 268 } 269 #endif 270 vn_lock(vp, NULL, LK_EXCLUSIVE | LK_RETRY, td); 271 *vpp = vp; 272 return 0; 273 } 274 275 static int 276 nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg, 277 struct thread *td) 278 { 279 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); 280 } 281 282 static int 283 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td) 284 { 285 int error; 286 struct statfs mstat; 287 288 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 289 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 290 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 291 292 bzero(&mstat, sizeof(mstat)); 293 294 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); 295 if (error) 296 return (error); 297 298 /* now copy across the "interesting" information and fake the rest */ 299 sbp->f_type = mstat.f_type; 300 sbp->f_flags = mstat.f_flags; 301 sbp->f_bsize = mstat.f_bsize; 302 sbp->f_iosize = mstat.f_iosize; 303 sbp->f_blocks = mstat.f_blocks; 304 sbp->f_bfree = mstat.f_bfree; 305 sbp->f_bavail = mstat.f_bavail; 306 sbp->f_files = mstat.f_files; 307 sbp->f_ffree = mstat.f_ffree; 308 if (sbp != &mp->mnt_stat) { 309 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 310 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 311 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 312 } 313 return (0); 314 } 315 316 static int 317 nullfs_sync(struct mount *mp, int waitfor, struct thread *td) 318 { 319 /* 320 * XXX - Assumes no data cached at null layer. 321 */ 322 return (0); 323 } 324 325 static int 326 nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp) 327 { 328 329 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 330 } 331 332 static int 333 nullfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp) 334 { 335 336 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 337 } 338 339 static int 340 nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp, 341 struct ucred **credanonp) 342 { 343 344 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 345 extflagsp, credanonp); 346 } 347 348 static int 349 nullfs_vptofh(struct vnode *vp, struct fid *fhp) 350 { 351 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 352 } 353 354 static int 355 nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg, 356 struct thread *td) 357 { 358 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, 359 arg, td); 360 } 361 362 363 static struct vfsops null_vfsops = { 364 nullfs_mount, 365 nullfs_start, 366 nullfs_unmount, 367 nullfs_root, 368 nullfs_quotactl, 369 nullfs_statfs, 370 nullfs_sync, 371 nullfs_vget, 372 nullfs_fhtovp, 373 nullfs_checkexp, 374 nullfs_vptofh, 375 nullfs_init, 376 nullfs_uninit, 377 nullfs_extattrctl, 378 }; 379 380 VFS_SET(null_vfsops, null, VFCF_LOOPBACK); 381