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 1.13 2004/10/12 19:21:04 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 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 thread *td) 86 { 87 int error = 0; 88 struct null_args args; 89 struct vnode *lowerrootvp, *vp; 90 struct vnode *nullm_rootvp; 91 struct null_mount *xmp; 92 u_int size; 93 int isvnunlocked = 0; 94 struct nameidata nd; 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 } 104 105 /* 106 * Get argument 107 */ 108 error = copyin(data, (caddr_t)&args, sizeof(struct null_args)); 109 if (error) 110 return (error); 111 112 /* 113 * Unlock lower node to avoid deadlock. 114 * (XXX) VOP_ISLOCKED is needed? 115 */ 116 if ((mp->mnt_vnodecovered->v_tag == VT_NULL) && 117 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) { 118 VOP_UNLOCK(mp->mnt_vnodecovered, 0, td); 119 isvnunlocked = 1; 120 } 121 /* 122 * Find lower node 123 */ 124 NDINIT(&nd, NAMEI_LOOKUP, CNP_FOLLOW | CNP_WANTPARENT | CNP_LOCKLEAF, 125 UIO_USERSPACE, args.target, td); 126 error = namei(&nd); 127 /* 128 * Re-lock vnode. 129 */ 130 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 131 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td); 132 133 if (error) 134 return (error); 135 NDFREE(&nd, NDF_ONLY_PNBUF); 136 137 /* 138 * Sanity check on lower vnode 139 */ 140 lowerrootvp = nd.ni_vp; 141 142 vrele(nd.ni_dvp); 143 nd.ni_dvp = NULLVP; 144 145 /* 146 * Check multi null mount to avoid `lock against myself' panic. 147 */ 148 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { 149 NULLFSDEBUG("nullfs_mount: multi null mount?\n"); 150 vput(lowerrootvp); 151 return (EDEADLK); 152 } 153 154 xmp = (struct null_mount *) malloc(sizeof(struct null_mount), 155 M_NULLFSMNT, M_WAITOK); /* XXX */ 156 157 /* 158 * Save reference to underlying FS 159 */ 160 xmp->nullm_vfs = lowerrootvp->v_mount; 161 162 vfs_add_vnodeops(&mp->mnt_vn_ops, null_vnodeop_entries); 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, td); 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, td); 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 */ 210 static int 211 nullfs_start(struct mount *mp, int flags, struct thread *td) 212 { 213 return (0); 214 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */ 215 } 216 217 /* 218 * Free reference to null layer 219 */ 220 static int 221 nullfs_unmount(struct mount *mp, int mntflags, struct thread *td) 222 { 223 void *mntdata; 224 int error; 225 int flags = 0; 226 227 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 228 229 if (mntflags & MNT_FORCE) 230 flags |= FORCECLOSE; 231 232 /* There is 1 extra root vnode reference (nullm_rootvp). */ 233 error = vflush(mp, 1, flags); 234 if (error) 235 return (error); 236 237 /* 238 * Finally, throw away the null_mount structure 239 */ 240 mntdata = mp->mnt_data; 241 mp->mnt_data = 0; 242 free(mntdata, M_NULLFSMNT); 243 return 0; 244 } 245 246 static int 247 nullfs_root(struct mount *mp, struct vnode **vpp) 248 { 249 struct thread *td = curthread; /* XXX */ 250 struct vnode *vp; 251 252 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 253 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 254 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 255 256 /* 257 * Return locked reference to root. 258 */ 259 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 260 vref(vp); 261 262 #ifdef NULLFS_DEBUG 263 if (VOP_ISLOCKED(vp, NULL)) { 264 Debugger("root vnode is locked.\n"); 265 vrele(vp); 266 return (EDEADLK); 267 } 268 #endif 269 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 270 *vpp = vp; 271 return 0; 272 } 273 274 static int 275 nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg, 276 struct thread *td) 277 { 278 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); 279 } 280 281 static int 282 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td) 283 { 284 int error; 285 struct statfs mstat; 286 287 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 288 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 289 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 290 291 bzero(&mstat, sizeof(mstat)); 292 293 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); 294 if (error) 295 return (error); 296 297 /* now copy across the "interesting" information and fake the rest */ 298 sbp->f_type = mstat.f_type; 299 sbp->f_flags = mstat.f_flags; 300 sbp->f_bsize = mstat.f_bsize; 301 sbp->f_iosize = mstat.f_iosize; 302 sbp->f_blocks = mstat.f_blocks; 303 sbp->f_bfree = mstat.f_bfree; 304 sbp->f_bavail = mstat.f_bavail; 305 sbp->f_files = mstat.f_files; 306 sbp->f_ffree = mstat.f_ffree; 307 if (sbp != &mp->mnt_stat) { 308 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 309 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 310 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 311 } 312 return (0); 313 } 314 315 static int 316 nullfs_sync(struct mount *mp, int waitfor, struct thread *td) 317 { 318 /* 319 * XXX - Assumes no data cached at null layer. 320 */ 321 return (0); 322 } 323 324 static int 325 nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp) 326 { 327 328 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 329 } 330 331 static int 332 nullfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp) 333 { 334 335 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 336 } 337 338 static int 339 nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp, 340 struct ucred **credanonp) 341 { 342 343 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 344 extflagsp, credanonp); 345 } 346 347 static int 348 nullfs_vptofh(struct vnode *vp, struct fid *fhp) 349 { 350 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 351 } 352 353 static int 354 nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg, 355 struct thread *td) 356 { 357 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, 358 arg, td); 359 } 360 361 362 static struct vfsops null_vfsops = { 363 nullfs_mount, 364 nullfs_start, 365 nullfs_unmount, 366 nullfs_root, 367 nullfs_quotactl, 368 nullfs_statfs, 369 nullfs_sync, 370 nullfs_vget, 371 nullfs_fhtovp, 372 nullfs_checkexp, 373 nullfs_vptofh, 374 nullfs_init, 375 nullfs_uninit, 376 nullfs_extattrctl, 377 }; 378 379 VFS_SET(null_vfsops, null, VFCF_LOOPBACK); 380