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 1.15 2004/12/17 00:18:30 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/nlookup.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 nlookupdata 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 lowerrootvp = NULL; 125 error = nlookup_init(&nd, args.target, UIO_USERSPACE, NLC_FOLLOW); 126 if (error == 0) 127 error = nlookup(&nd); 128 if (error == 0) { 129 error = cache_vget(nd.nl_ncp, nd.nl_cred, LK_EXCLUSIVE, 130 &lowerrootvp); 131 } 132 nlookup_done(&nd); 133 134 /* 135 * Re-lock vnode. 136 */ 137 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) 138 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td); 139 if (error) 140 return (error); 141 142 /* 143 * Sanity check on lower vnode 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 vfs_add_vnodeops(mp, &mp->mnt_vn_norm_ops, null_vnodeop_entries); 162 163 /* 164 * Save reference. Each mount also holds 165 * a reference on the root vnode. 166 */ 167 error = null_node_create(mp, lowerrootvp, &vp); 168 /* 169 * Unlock the node (either the lower or the alias) 170 */ 171 VOP_UNLOCK(vp, 0, td); 172 /* 173 * Make sure the node alias worked 174 */ 175 if (error) { 176 vrele(lowerrootvp); 177 free(xmp, M_NULLFSMNT); /* XXX */ 178 return (error); 179 } 180 181 /* 182 * Keep a held reference to the root vnode. 183 * It is vrele'd in nullfs_unmount. 184 */ 185 nullm_rootvp = vp; 186 nullm_rootvp->v_flag |= VROOT; 187 xmp->nullm_rootvp = nullm_rootvp; 188 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) 189 mp->mnt_flag |= MNT_LOCAL; 190 mp->mnt_data = (qaddr_t) xmp; 191 vfs_getnewfsid(mp); 192 193 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 194 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size); 195 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 196 &size); 197 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 198 (void)nullfs_statfs(mp, &mp->mnt_stat, td); 199 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", 200 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 201 return (0); 202 } 203 204 /* 205 * VFS start. Nothing needed here - the start routine 206 * on the underlying filesystem will have been called 207 * when that filesystem was mounted. 208 */ 209 static int 210 nullfs_start(struct mount *mp, int flags, struct thread *td) 211 { 212 return (0); 213 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */ 214 } 215 216 /* 217 * Free reference to null layer 218 */ 219 static int 220 nullfs_unmount(struct mount *mp, int mntflags, struct thread *td) 221 { 222 void *mntdata; 223 int error; 224 int flags = 0; 225 226 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); 227 228 if (mntflags & MNT_FORCE) 229 flags |= FORCECLOSE; 230 231 /* There is 1 extra root vnode reference (nullm_rootvp). */ 232 error = vflush(mp, 1, flags); 233 if (error) 234 return (error); 235 236 /* 237 * Finally, throw away the null_mount structure 238 */ 239 mntdata = mp->mnt_data; 240 mp->mnt_data = 0; 241 free(mntdata, M_NULLFSMNT); 242 return 0; 243 } 244 245 static int 246 nullfs_root(struct mount *mp, struct vnode **vpp) 247 { 248 struct thread *td = curthread; /* XXX */ 249 struct vnode *vp; 250 251 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, 252 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 253 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 254 255 /* 256 * Return locked reference to root. 257 */ 258 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; 259 vref(vp); 260 261 #ifdef NULLFS_DEBUG 262 if (VOP_ISLOCKED(vp, NULL)) { 263 Debugger("root vnode is locked.\n"); 264 vrele(vp); 265 return (EDEADLK); 266 } 267 #endif 268 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 269 *vpp = vp; 270 return 0; 271 } 272 273 static int 274 nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg, 275 struct thread *td) 276 { 277 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td); 278 } 279 280 static int 281 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td) 282 { 283 int error; 284 struct statfs mstat; 285 286 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, 287 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, 288 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); 289 290 bzero(&mstat, sizeof(mstat)); 291 292 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td); 293 if (error) 294 return (error); 295 296 /* now copy across the "interesting" information and fake the rest */ 297 sbp->f_type = mstat.f_type; 298 sbp->f_flags = mstat.f_flags; 299 sbp->f_bsize = mstat.f_bsize; 300 sbp->f_iosize = mstat.f_iosize; 301 sbp->f_blocks = mstat.f_blocks; 302 sbp->f_bfree = mstat.f_bfree; 303 sbp->f_bavail = mstat.f_bavail; 304 sbp->f_files = mstat.f_files; 305 sbp->f_ffree = mstat.f_ffree; 306 if (sbp != &mp->mnt_stat) { 307 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid)); 308 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN); 309 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN); 310 } 311 return (0); 312 } 313 314 static int 315 nullfs_sync(struct mount *mp, int waitfor, struct thread *td) 316 { 317 /* 318 * XXX - Assumes no data cached at null layer. 319 */ 320 return (0); 321 } 322 323 static int 324 nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp) 325 { 326 327 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp); 328 } 329 330 static int 331 nullfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp) 332 { 333 334 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp); 335 } 336 337 static int 338 nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp, 339 struct ucred **credanonp) 340 { 341 342 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam, 343 extflagsp, credanonp); 344 } 345 346 static int 347 nullfs_vptofh(struct vnode *vp, struct fid *fhp) 348 { 349 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp); 350 } 351 352 static int 353 nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg, 354 struct thread *td) 355 { 356 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname, 357 arg, td); 358 } 359 360 361 static struct vfsops null_vfsops = { 362 nullfs_mount, 363 nullfs_start, 364 nullfs_unmount, 365 nullfs_root, 366 nullfs_quotactl, 367 nullfs_statfs, 368 nullfs_sync, 369 nullfs_vget, 370 nullfs_fhtovp, 371 nullfs_checkexp, 372 nullfs_vptofh, 373 nullfs_init, 374 nullfs_uninit, 375 nullfs_extattrctl, 376 }; 377 378 VFS_SET(null_vfsops, null, VFCF_LOOPBACK); 379